[libpng16] Imported from libpng-1.6.13beta04.tar

[libpng16] Eliminated use of "$<" when copying $PNGLIBCONF_H_PREBUILT in
makefiles. This does not work on some versions of make; bug introduced in libpng version 1.6.11.
2025-07-10 18:04:09 +02:00 · 2014-08-07 19:54:10 -05:00 · 2014-08-07 19:51:35 -05:00 · 2014-08-03 19:53:45 -05:00 · 2014-08-02 21:32:49 -05:00 · 2014-08-02 21:28:14 -05:00
111 changed files with 4779 additions and 7229 deletions
--- a/737
+++ b/737
@@ -1,5 +1,4 @@
-
-Libpng 1.7.0beta52 - February 21, 2015
+Libpng 1.6.13beta04 - August 8, 2014

 This is not intended to be a public release.  It will be replaced
 within a few weeks by a public version or by another test version.
@@ -9,724 +8,54 @@ Files available for download:
 Source files with LF line endings (for Unix/Linux) and with a
 "configure" script

-   1.7.0beta52.tar.xz (LZMA-compressed, recommended)
-   1.7.0beta52.tar.gz
+   1.6.13beta04.tar.xz (LZMA-compressed, recommended)
+   1.6.13beta04.tar.gz

 Source files with CRLF line endings (for Windows), without the
 "configure" script

-   lp170b52.7z  (LZMA-compressed, recommended)
-   lp170b52.zip
+   lp1613b04.7z  (LZMA-compressed, recommended)
+   lp1613b04.zip

 Other information:

-   1.7.0beta52-README.txt
-   1.7.0beta52-LICENSE.txt
-   libpng-1.7.0beta52-*.asc (armored detached GPG signatures)
+   1.6.13beta04-README.txt
+   1.6.13beta04-LICENSE.txt
+   libpng-1.6.13beta04-*.asc (armored detached GPG signatures)

-Changes since the last public release (1.6.0):
+Changes since the last public release (1.6.13):

-Version 1.7.0alpha01 [December 15, 2012]
-  Started 1.7.0 branch from libpng-1.6.0beta33.
-  Made 8-bit compose and rgb_to_grayscale accuracy improvements.  These
-    changes cause 16-bit arithmetic to be used for 8-bit data in the gamma
-    corrected compose and grayscale operations.  The arithmetic errors have
-    three sources all of which are fixed in this commit:
-    1) 8-bit linear calculations produce massive errors for lower intensity
-       values.
-    2) The old 16-bit "16 to 8" gamma table code erroneously wrote the lowest
-       output value into a table entry which corresponded to multiple output
-       values (so where the value written should have been the closest to the
-       transformed input value.)
-    3) In a number of cases the code to access the 16-bit table did not round;
-       it did a simple shift, which was wrong and made the side effects of (2)
-       even worse.
-  The new gamma code does not have the 16-to-8 problem at the cost of slightly
-    more calculations and the algorithm used to minimize the number of
-    calculations has been extended to all the 16-bit tables; it has advantages
-    for any significant gamma correction.
-  Rearranged png_struct, remove unused members, change png_set_filter handling
-    png_struct members rearranged - partly to reorder to avoid packing, partly
-    to put frequently accessed members at the start and partly to make
-    the grouping more clear. png_set_filter code has been rewritten and the
-    code shared with png_write_start_row moved to a common function.  Comments
-    in png.h have been made more clear. Minor fixes to
-    contrib/libtests/timepng.c and some of the png_*_tRNS logic, including
-    more error detection in png_set_tRNS.
-  Cleaned up USER_LIMITS feature, removing members from png_struct when not
-    required.
-  Rearranged ARM-NEON optimizations to isolate the machine specific code to
-    the hardware subdirectory, and add comments to pngrutil.c so that
-    implementors of other optimizations will know what to do.
-  Fixed cases of unquoted DESTDIR in Makefile.am.
-  Rebuilt Makefile.in, configure, etc., with autoconf-2.69 and automake-1.12.5.
+Version 1.6.13beta01 [July 4, 2014]
+  Quieted -Wsign-compare and -Wclobber compiler warnings in
+    contrib/pngminus/*.c
+  Added "(void) png_ptr;" where needed in contrib/gregbook to quiet
+    compiler complaints about unused pointers.
+  Split a long output string in contrib/gregbook/rpng2-x.c.
+  Added "PNG_SET_OPTION" requirement for sRGB chunk support to pnglibconf.dfa,
+    Needed for write-only support (John Bowler).
+  Changed "if defined(__ARM_NEON__)" to
+    "if (defined(__ARM_NEON__) || defined(__ARM_NEON))" (James Wu).
+  Fixed clang no-warning builds: png_digit was defined but never used.
+    
+Version 1.6.13beta02 [July 21, 2014]
+  Fixed an incorrect separator ("/" should be "\") in scripts/makefile.vcwin32
+    (bug report from Wolfgang S. Kechel).  Bug was introduced in libpng-1.6.11.
+    Also fixed makefile.bc32, makefile.bor, makefile.msc, makefile.intel, and
+    makefile.tc3 similarly.

-Version 1.7.0alpha02 [December 17, 2012]
-  Removed functions that were deprecated in libpng-1.6.0:
-    png_reset_zstream(), png_info_init_3(), and png_data_freer() and its
-    associated flags.
-  Removed some duplicated lines from contrib/tools/scale.c and png.c.
-  Changed some instances of png_warning() to png_app_error().
-  Updated some left over "1.6.0beta32" in code sources.
-  Fixed a "png_structp" prototype (should be png_structrp) in arm_init.c
-  Updated the version-number hack in pngvalid.c
-
-Version 1.7.0alpha03 [December 19, 2012]
-  Cleaned up and enhanced the configure option; libpng now correctly
-    links and tests against zlib with a prefix; tests have been clarified; and
-    irrelevant or obsolete things (as defined by the autotools man page) have
-    been removed.
-  Documented new PNG_ABORT behavior in the manual and commentary in pngerror.c
-  Cleaned up whitespace in the synopsis portion of the manpage "libpng.3"
-  Fixed previous support for Z_PREFIX in configure builds, corrected sCAL APIs;
-    some of these use floating point arithmetic so they need to be disabled if
-    floating point arithmetic is switched off.  This is a quiet API change -
-    previously it appeared that the APIs were supported if fixed point
-    arithmetic was used internally, however they required certain APIs (floor,
-    modf, frexp, atof) that are part of C floating point support. Changed
-    png_fixed and the gamma code specific version of the same to avoid floor(),
-    which may be a library function (not an intrinsic). Removed unused #if 0
-    code.
-  Disassembled the version number in scripts/options.awk (necessary for
-    building on SunOs).
-
-Version 1.7.0alpha04 [December 23, 2012]
-  Added scripts/makefile.msys contributed by Christopher M. Wheeler
-  Made default Zlib compression settings be configurable. This adds #defines to
-    pnglibconf.h to control the defaults.
-  Fixed Windows build issues, enabled ARM compilation. Various warnings issued
-    by earlier versions of GCC fixed for Cygwin and Min/GW (which both use old
-    GCCs.) ARM support is enabled by default in zlib.props (unsupported by
-    Microsoft) and ARM compilation is made possible by deleting the check for
-    x86. The test programs cannot be run because they are not signed.
-
-Version 1.7.0alpha05 [December 24, 2012]
-  Discontinued distributing libpng-1.x.x.tar.bz2.
-  Discontinued distributing libpng-1.7.0-1.6.0-diff.txt and similar.
-
-Version 1.7.0alpha06 [January 1, 2013]
-  Fixed 'make distcheck' on SUN OS - libpng.so was not being removed
-
-Version 1.7.0alpha07 [January 10, 2013]
-  Fixed conceivable but difficult to repro overflow. Also added two test
-    programs to generate and test a PNG which should have the problem.
-
-Version 1.7.0alpha08 [January 17, 2013]
-  Corrected previous attempt at overflow detection in png_set_unknown_chunks()
-  (CVE-2013-7353).  Added overflow detection in png_set_sPLT() and
-  png_set_text_2() (CVE-2013-7354).
-
-Version 1.7.0alpha09 [January 21, 2013]
-  Pulled changes to multi-chunk handling from libpng-1.6.0beta40.
-
-Version 1.7.0alpha10 [February 5, 2013]
-  Make symbol prefixing work with the ARM neon optimizations. Also
-    allow pngpriv.h to be included for preprocessor definitions only, so
-    it can be used in non-C/C++ files.
-  Added png_get_palette_max() function.
-  Changed png_size_t to size_t throughout headers, make sRGB check numbers
-    consistent.
-  Fixed ARM support (Mans Rullgard).
-  Removed stray out-of-order #endif and #ifdef (Mans Rullgard).
-  Ported libpng 1.5 options.awk/dfn file handling to 1.7, fixed one bug.
-  Rebuilt Makefile.in, configure, etc., with autoconf-2.69 and automake-1.13.
-  Minor fixes to assembler changes, verified with a dummy .S file
-  Removed cc -E workround, corrected png_get_palette_max API. Tested on
-    SUN OS cc 5.9, which demonstrates the tokenization problem previously
-    avoided by using /lib/cpp.  Since all .dfn output is now protected
-    in double quotes unless it is to be macro substituted the fix should work
-    everywhere.
-
-Version 1.7.0beta01 [February 15, 2013]
-  Enable parallel tests and rearrange TESTS order to take advantage of
-    the massive speed improvements use a make capable of parallel builds
-    on a multi-CPU machine and pass the right arguments to make (-j10000
-    for GNU make) to get the build to run in parallel.
-  Fixed previous support for Z_PREFIX in configure builds, corrected
-    sCAL APIs; some of these use floating point arithmetic so need to be
-    disabled if floating point arithmetic is switched off.  This is a quiet API
-    change - previously it appeared that the APIs were supported if fixed point
-    arithmetic was used internally, however they required certain APIs (floor,
-    modf, frexp, atof) that are part of C floating point support. Changed
-    png_fixed and the gamma code specific version of the same to avoid floor(),
-    which may be a library function (not an intrinsic). Removed unused #if 0
-    code.
-  Fixed make distcheck to skip over the test result files. They were
-    being included because the whole of the 'tests' directory is included,
-    fixed to just include the actual test files and tests/pngstest.  Also
-    reverted the previous erroneous change to remove the ${srcdir} from the
-    front of contrib, scripts, projects and added an explanation of what is
-    going on to Makefile.am
-  Fixed missing dependency in --prefix builds. The intermediate
-    internal 'prefix.h' file can only be generated correctly after pnglibconf.h,
-    however the dependency was not in Makefile.am.  The symptoms are
-    unpredictable depending on the order make chooses to build pngprefix.h and
-    pnglibconf.h, often the error goes unnoticed because there is a system
-    pnglibconf.h to use instead.
-  Accept "," as a separator in pnglibconf.dfa and allow for
-    continuation lines. This adds to the syntax of "option" and "chunk" lines,
-    allowing the elements to be separated by a "," at the end of an element and
-    interpreting a "," at end of line as a continuation - so the following line
-    is read.  The new syntax is optional and solely provided for readability.
-  Enclosed the new png_get_palette_max in #ifdef PNG_GET_PALETTE_MAX_SUPPORTED
-    block, and revised pnglibconf.h and pnglibconf.h.prebuilt accordingly.
-
-Version 1.7.0beta02 [February 18, 2013]
-  Fixed a race condition in the creation of the build 'scripts' directory
-    while building with a parallel make.
-  Use approved/supported Android method to check for NEON, use Linux/POSIX
-    1003.1 API to check /proc/self/auxv avoiding buffer allocation and other
-    library calls (ported from libpng15).
-  Use parentheses more consistently in "#if defined(MACRO)" tests.
-  Folded long lines.
-
-Version 1.7.0beta03 [February 22, 2013]
-  Reenabled code to allow zero length PLTE chunks for MNG.
-  Fixed ALIGNED_MEMORY support.
-  Allow run-time ARM NEON checking to be disabled. A new configure option:
-    --enable-arm-neon=always will stop the run-time checks. New checks
-    within arm/arm_init.c will cause the code not to be compiled unless
-    __ARM_NEON__ is set. This should make it fail safe (if someone asks
-    for it on then the build will fail if it can't be done.)
-  Updated the INSTALL document.
-
-Version 1.7.0beta04 [February 27, 2013]
-  Revised INSTALL to recommend using CPPFLAGS instead of INCLUDES.
-  Revised scripts/makefile.freebsd to respect ZLIBLIB and ZLIBINC.
-  Revised scripts/dfn.awk to work with the buggy MSYS awk that has trouble
-    with CRLF line endings.
-
-Version 1.7.0beta05 [March 5, 2013]
-  Avoid a possible memory leak in contrib/gregbook/readpng.c
-  Changed user chunk callback API to respect global and per chunk defaults.
-    Previously a return of 0 from a user chunk callback would result in the
-    chunk being saved (if this was safe, even if the chunk was unsafe-to-copy);
-    this change respects the defaults set by the application, so unknown chunks
-    can be discarded by default and known-safe ones preserved.
-  Corrected Android builds and corrected libpng.vers with symbol
-    prefixing. This adds an API to set optimization options externally,
-    providing an alternative and general solution for the non-portable
-    run-time tests used by the ARM Neon code.  It also makes those tests
-    compile and link on Android.  The order of settings vs options in
-    pnglibconf.h is reversed to allow settings to depend on options and
-    options can now set (or override) the defaults for settings.
-
-Version 1.7.0beta06 [March 13, 2013]
-  Corrected simplified API default gamma for color-mapped output, added
-    a flag to change default. In 1.6.0 when the simplified API was used
-    to produce color-mapped output from an input image with no gamma
-    information the gamma assumed for the input could be different from
-    that assumed for non-color-mapped output.  In particular 16-bit depth
-    input files were assumed to be sRGB encoded, whereas in the 'direct'
-    case they were assumed to have linear data.  This was an error.  The
-    fix makes the simplified API treat all input files the same way and
-    adds a new flag to the png_image::flags member to allow the
-    application/user to specify that 16-bit files contain sRGB data
-    rather than the default linear.
-  Fixed bugs in the pngpixel and makepng test programs.
-  Fixed CMakelists.txt to allow building a single variant of the library
-    (Claudio Bley):
-  Introduced a PNG_LIB_TARGETS variable that lists all activated library
-    targets.  It is an error if this variable ends up empty, ie. you have
-    to build at least one library variant.
-  Made the *_COPY targets only depend on library targets actually being build.
-  Use PNG_LIB_TARGETS to unify a code path.
-  Changed the CREATE_SYMLINK macro to expect the full path to a file as the
-    first argument. When symlinking the filename component of that path is
-    determined and used as the link target.
-  Use copy_if_different in the CREATE_SYMLINK macro.
-  Eliminated two warnings from the Intel C compiler. The warnings are
-    technically valid, although a reasonable treatment of division would
-    show it to be incorrect.
-
-Version 1.7.0beta07 [April 14, 2013]
-  Updated documentation of 1.5.x to 1.6.x changes in iCCP chunk handling.
-  Fixed incorrect warning of excess deflate data. End condition - the
-    warning would be produced if the end of the deflate stream wasn't read
-    in the last row.  The warning is harmless.
-  Corrected the test on user transform changes on read. It was in the
-    png_set of the transform function, but that doesn't matter unless the
-    transform function changes the rowbuf size, and that is only valid if
-    transform_info is called.
-  Corrected a misplaced closing bracket in contrib/libtests/pngvalid.c
-    (Flavio Medeiros).
-  Corrected length written to uncompressed iTXt chunks (Samuli Suominen).
-
-Version 1.7.0beta08 [April 18, 2013]
-  Added contrib/tools/fixitxt.c, to repair the erroneous iTXt chunk length
-    written by libpng-1.6.0 and 1.6.1.
-  Disallow storing sRGB information when the sRGB is not supported.
-
-Version 1.7.0beta09 [April 24, 2013]
-  Exposed PNG chunk types in png.h
-  Modified png_uint_32 macros/code to make as few assumptions as possible
-  Revised stack marking in arm/filter_neon.S and configure.ac
-  Ensure that NEON filter stuff is completely disabled when switched 'off'.
-    Previously the ARM NEON specific files were still built if the option
-    was switched 'off' as opposed to being explicitly disabled.
-
-Version 1.7.0beta10 [April 24, 2013]
-  Attempt to fix the PNG_ARM_NEON configuration mess.
-
-Version 1.7.0beta11 [April 26, 2013]
-  Test for 'arm*', not just 'arm' in the host_cpu configure variable.
-
-Version 1.7.0beta12 [April 30, 2013]
-  Added png_app_warning for out-of-range unknown chunk index in
-    png_set_unknown_chunk_location().
-  Expanded manual paragraph about writing private chunks.
-  Avoid dereferencing NULL pointer possibly returned from
-     png_create_write_struct() (Andrew Church).
-
-Version 1.7.0beta13 [May 12, 2013]
-  Revised contrib/pngminim/*/makefile to generate pnglibconf.h with the
-    right zlib header files.
-  Separated CPPFLAGS and CFLAGS in contrib/pngminim/*/makefile
-  Updated contrib/pngminus/pnm2png.c (Paul Stewart):
-    Check for EOF
-    Ignore "#" delimited comments in input file to pnm2png.c.
-    Fixed whitespace handling
-    Added a call to png_set_packing()
-    Initialize dimension values so if sscanf fails at least we have known
-      invalid values.
-  Calculate our own zlib windowBits when decoding rather than trusting the
-    CMF bytes in the PNG datastream.
-  Added an option to force maximum window size for inflating, which was
-    the behavior of libpng15 and earlier.
-  Added png-fix-itxt and png-fix-too-far-back to the built programs and
-    removed warnings from the source code and timepng that are revealed as
-    a result.
-  Detect wrong libpng versions linked to png-fix-too-far-back, which currently
-    only works with libpng versions that can be made to reliably fail when
-    the deflate data contains an out-of-window reference.  This means only
-    1.6 and later.
-  Attempt to detect configuration issues with png-fix-too-far-back, which
-    requires both the correct libpng and the correct zlib to function
-    correctly.
-  Check ZLIB_VERNUM for mismatches, enclose #error in quotes
-  Added information in the documentation about problems with and fixes for
-    the bad CRC and bad iTXt chunk situations.
-
-Version 1.7.0beta14 [June 8, 2013]
-  Removed a redundant test in png_set_IHDR().
-  Added set(CMAKE_CONFIGURATION_TYPES ...) to CMakeLists.txt (Andrew Hundt)
-  Deleted set(CMAKE_BUILD_TYPE) block from CMakeLists.txt
-  Enclose the prototypes for the simplified write API in #ifdef STDIO/#endif
-  Make ARM NEON support work at compile time (not just configure time).
-    This moves the test on __ARM_NEON__ into pngconf.h to avoid issues when
-    using a compiler that compiles for multiple architectures at one time.
-  Removed PNG_FILTER_OPTIMIZATIONS and PNG_ARM_NEON_SUPPORTED from
-    pnglibconf.h, allowing more of the decisions to be made internally
-    (pngpriv.h) during the compile.  Without this, symbol prefixing is broken
-    under certain circumstances on ARM platforms.  Now only the API parts of
-    the optimizations ('check' vs 'api') are exposed in the public header files
-    except that the new setting PNG_ARM_NEON_OPT documents how libpng makes the
-    decision about whether or not to use the optimizations.
-  Protect symbol prefixing against CC/CPPFLAGS/CFLAGS useage.
-    Previous iOS/Xcode fixes for the ARM NEON optimizations moved the test
-    on __ARM_NEON__ from configure time to compile time.  This breaks symbol
-    prefixing because the definition of the special png_init_filter_functions
-    call was hidden at configure time if the relevant compiler arguments are
-    passed in CFLAGS as opposed to CC.  This change attempts to avoid all
-    the confusion that would result by declaring the init function even when
-    it is not used, so that it will always get prefixed.
-
-Version 1.7.0beta15 [June 18, 2013]
-  Revised libpng.3 so that "doclifter" can process it.
-
-Version 1.7.0beta16 [July 5, 2013]
-  Revised example.c to illustrate use of PNG_DEFAULT_sRGB and PNG_GAMMA_MAC_18
-    as parameters for png_set_gamma().  These have been available since
-    libpng-1.5.4.
-  Renamed contrib/tools/png-fix-too-far-back.c to pngfix.c and revised it
-    to check all compressed chunks known to libpng.
-  Updated documentation to show default behavior of benign errors correctly.
-  Added perfect hash code generation for lists of PNG chunks. This is
-    a work in progress; checked in for use in pngfix.c
-  Ported ARM no-read patch from libpng16.
-  Ported pngfix.c patches from libpng16.
-
-Version 1.7.0beta17 [August 21, 2013]
-  Revised manual about changes in iTXt chunk handling made in libpng-1.6.0.
-  Added "/* SAFE */" comments in pngrutil.c and pngrtran.c where warnings
-    may be erroneously issued by code-checking applications.
-  Added information about png_set_options() to the manual.
-  Delay calling png_init_filter_functions() until a row with nonzero filter
-    is found.
-
-Version 1.7.0beta18 [September 16, 2013]
-  Fixed inconsistent conditional compilation of png_chunk_unknown_handling()
-    prototype, definition, and usage.  Made it depend on
-    PNG_HANDLE_AS_UNKNOWN_SUPPORTED everywhere.
-
-Version 1.7.0beta19 [September 30, 2013]
-  Reverted the change to unknown handling #defines; the change breaks 'NOREAD'
-    builds.
-  Fixed default behavior of ARM_NEON_API. If the ARM NEON API option is
-    compiled without the CHECK option it defaulted to on, not off.
-  Catch up with recent libpng16 changes; unknown handling and spelling
-    corrections
-  Avoid up-cast warnings in pngvalid.c. On ARM the alignment requirements of
-    png_modifier are greater than that of png_store and as a consequence
-    compilation of pngvalid.c results in a warning about increased alignment
-    requirements because of the bare cast to (png_modifier*).  The code is
-    safe, because the pointer is known to point to a stack allocated
-    png_modifier, but this change avoids the warning.
-  Fixed some grammatical changes and updated the png chunks list.
-
-Version 1.7.0beta20 [October 13, 2013]
-  Made changes for compatibility with automake 1.14:
-    1) Added the 'compile' program to the list of programs that must be cleaned
-       in autogen.sh
-    2) Added 'subdir-objects' which causes .c files in sub-directories to be
-       compiled such that the corresponding .o files are also in the
-       sub-directory.  This is because automake 1.14 warns that the
-       current behavior of compiling to the top level directory may be removed
-       in the future.
-    3) Updated dependencies on pnglibconf.h to match the new .o locations and
-       added all the files in contrib/libtests and contrib/tools that depend
-       on pnglibconf.h
-    4) Added 'BUILD_SOURCES = pnglibconf.h'; this is the automake recommended
-       way of handling the dependencies of sources that are machine generated;
-       unfortunately it only works if the user does 'make all' or 'make check',
-       so the dependencies (3) are still required.
-  Cleaned up (char*) casts of zlib messages. The latest version of the Intel C
-    compiler complains about casting a string literal as (char*), so copied the
-    treatment of z_const from the library code into pngfix.c
-  Simplified error message code in pngunknown. The simplification has the
-    useful side effect of avoiding a bogus warning generated by the latest
-    version of the Intel C compiler (it objects to
-    condition ? string-literal : string-literal).
-  Make autogen.sh work with automake 1.13 as well as 1.14. Do this by always
-    removing the 1.14 'compile' script but never checking for it.
-
-Version 1.7.0beta21 [November 2, 2013]
-  Added ARMv8 support (James Yu <james.yu at linaro.org>).  Added file
-    arm/filter_neon_intrinsics.c; enable with -mfpu=neon.
-  Revised pngvalid to generate size images with as many filters as it can
-    manage, limited by the number of rows.
-  Cleaned up ARM NEON compilation handling. The tests are now in pngpriv.h
-    and detect the broken GCC compilers.
-  Allow clang derived from older GCC versions to use ARM intrinsics. This
-    causes all clang builds that use -mfpu=neon to use the intrinsics code,
-    not the assembler code.  This has only been tested on iOS 7. It may be
-    necessary to exclude some earlier clang versions but this seems unlikely.
-  Changed NEON implementation selection mechanism. This allows assembler
-    or intrinsics to be turned on at compile time during the build by defining
-    PNG_ARM_NEON_IMPLEMENTATION to the correct value (2 or 1).  This macro
-    is undefined by default and the build type is selected in pngpriv.h.
-
-Version 1.7.0beta22 [November 7, 2013]
-  Fixed #include in filter_neon_intrinsics.c and ctype macros. The ctype char
-    checking macros take an unsigned char argument, not a signed char.
-
-Version 1.7.0beta23 [November 24, 2013]
-  Changed #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED in pngpread.c to
-    #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED to be consistent with
-    what is in pngpriv.h.
-  Moved prototype for png_handle_unknown() in pngpriv.h outside of
-    the #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED/#endif block.
-  Added "-Wall" to CFLAGS in contrib/pngminim/*/makefile
-  Conditionally compile some unused functions reported by -Wall in
-    pngminim.
-  Fixed 'minimal' builds. Various obviously useful minimal configurations
-    don't build because of missing contrib/libtests test programs and
-    overly complex dependencies in scripts/pnglibconf.dfa. This change
-    adds contrib/conftest/*.dfa files that can be used in automatic build
-    scripts to ensure that these configurations continue to build.
-  Enabled WRITE_INVERT and WRITE_PACK in contrib/pngminim/encoder.
-  Fixed pngvalid 'fail' function declaration on the Intel C Compiler.
-    This reverts to the previous 'static' implementation and works round
-    the 'unused static function' warning by using PNG_UNUSED().
-
-Version 1.7.0beta24 [December 15, 2013]
-  Removed or marked PNG_UNUSED some harmless "dead assignments" reported
-    by clang scan-build.
-  Changed tabs to 3 spaces in png_debug macros and changed '"%s"m'
-    to '"%s" m' to improve portability among compilers.
-  Changed png_free_default() to free() in pngtest.c
-  Tidied up pngfix inits and fixed pngtest no-write builds.
-  Bookkeeping: Moved functions around (no changes). Moved transform
-    function definitions before the place where they are called so that
-    they can be made static. Move the intrapixel functions and the
-    grayscale palette builder out of the png?tran.c files. The latter
-    isn't a transform function and is no longer used internally, and the
-    former MNG specific functions are better placed in pngread/pngwrite.c
-  Made transform implementation functions static. This makes the internal
-    functions called by png_do_{read|write}_transformations static. On an
-    x86-64 DLL build (Gentoo Linux) this reduces the size of the text
-    segment of the DLL by 1208 bytes, about 0.6%. It also simplifies
-    maintenance by removing the declarations from pngpriv.h and allowing
-    easier changes to the internal interfaces.
-  Handle zero-length PLTE chunk or NULL palette with png_error()
-    instead of png_chunk_report(), which by default issues a warning
-    rather than an error, leading to later reading from a NULL pointer
-    (png_ptr->palette) in png_do_expand_palette(). This is CVE-2013-6954
-    and VU#650142.  Libpng-1.6.1 through 1.6.7 and libpng-1.7.0beta03
-    through 1.7.0beta23 are vulnerable.  Libpng-1.6.0 and earlier do not
-    have the bug.
-
-Version 1.7.0beta25 [December 26, 2013]
-  Merged files with version 1.6.8 that have not changed since then.
-  Rebuilt configure scripts with automake-1.14.1 and autoconf-2.69
-
-Version 1.7.0beta26 [January 1, 2014]
-  Added libpng 1.5 checks to pngvalid.c
-  Merged with 1.5 and 1.6 changes to create a single pngvalid.c
-  Added dSIG to chunk list in png.h
-  Removed #error macro from contrib/tools/pngfix.c (Thomas Klausner).
-  Merged pngrio.c, pngtrans.c, and pngwio.c with libpng-1.6.9
-  Fixed test programs for interlace options. Made pngvalid.c and
-    pngtest.c work correctly when READ_INTERLACING and/or WRITE_INTERLACING
-    are switched off.
-  Changed pngvalid.c to support libpng 1.5, which does not support
-    the PNG_MAXIMUM_INFLATE_WINDOW option, so #define it out when
-    appropriate in pngvalid.c
-  Allow unversioned links created on install to be disabled in configure.
-    In configure builds 'make install' changes/adds links like png.h
-    and libpng.a to point to the newly installed, versioned, files (e.g.
-    libpng17/png.h and libpng17.a). Three new configure options and some
-    rearrangement of Makefile.am allow creation of these links to be disabled.
-
-Version 1.7.0beta27 [January 10, 2014]
-  Removed potentially misleading warning from png_check_IHDR().
-
-Version 1.7.0beta28 [January 20, 2014]
-  Updated scripts/makefile.* to use CPPFLAGS (Cosmin).
-  Added clang attribute support (Cosmin).
-
-Version 1.7.0beta29 [January 30, 2014]
-  Quiet an uninitialized memory warning from VS2013 in png_get_png().
-
-Version 1.7.0beta30 [February 2, 2014]
-  Fixed a large number of instances where PNGCBAPI was omitted from
-    function definitions.
-  Added pngimage test program for png_read_png and png_write_png. This
-    is a work-in-progress; no tests are run automatically at present and
-    the program by virtue of exhaustively testing all the transforms is
-    very slow.
-
-Version 1.7.0beta31 [February 6, 2014]
-  Make png_read_png() and png_write_png() prototypes in png.h depend
-    upon PNG_READ_SUPPORTED and PNG_WRITE_SUPPORTED.
-  Removed dependence on !PNG_READ_EXPAND_SUPPORTED for calling
-    png_set_packing() in png_read_png().
-  Completed full working pngimage test program and added two test scripts.
-  Fixed combination of ~alpha with shift. On read invert alpha, processing
-    occurred after shift processing, which causes the final values to be
-    outside the range that should be produced by the shift. Reversing the
-    order on read makes the two transforms work together correctly and mirrors
-    the order used on write.
-  Do not read invalid sBIT chunks. Previously libpng only checked sBIT
-    values on write, so a malicious PNG writer could therefore cause
-    the read code to return an invalid sBIT chunk, which might lead to
-    application errors or crashes.  Such chunks are now skipped (with
-    chunk_benign_error).
-  Restored a line, "c = b;", that was inadvertently deleted from the
-    PAETH filtering code from libpng-1.7.0beta24/pngrutil.c. Deleted
-    the other instance of "c = b;" which is the one that triggered a
-    scan-build warning.
-  Support builds with unsupported PNG_TRANSFORM_* values.  All of the
-    PNG_TRANSFORM_* values are always defined in png.h and, because they
-    are used for both read and write in some cases, it is not reliable
-    to #if out ones that are totally unsupported. This change adds error
-    detection in png_read_image() and png_write_image() to do a
-    png_app_error() if the app requests something that cannot be done
-    and it adds corresponding code to pngimage.c to handle such options
-    by not attempting to test them.
-
-Version 1.7.0beta32 [February 26, 2014]
-  Moved redefines of png_error(), png_warning(), png_chunk_error(),
-    and png_chunk_warning() from pngpriv.h to png.h to make them visible
-    to libpng-calling applications.
-  Moved OS dependent code from arm/arm_init.c, to allow the included
-    implementation of the ARM NEON discovery function to be set at
-    build-time and provide sample implementations from the current code in the
-    contrib/arm-neon subdirectory. The __linux__ code has also been changed to
-    compile and link on Android by using /proc/cpuinfo, and the old linux code
-    is in contrib/arm-neon/linux-auxv.c.  The new code avoids POSIX and Linux
-    dependencies apart from opening /proc/cpuinfo and is C90 compliant.
-  Check for info_ptr == NULL early in png_read_end() so we don't need to
-    run all the png_handle_*() and depend on them to return if info_ptr == NULL.
-    This improves the performance of png_read_end(png_ptr, NULL) and makes
-    it more robust against future programming errors.
-  Check for __has_extension before using it in pngconf.h, to
-    support older Clang versions (Jeremy Sequoia).
-  Use a user warning handler in contrib/gregbook/readpng2.c instead of default,
-    so warnings will be put on stderr even if libpng has CONSOLE_IO disabled.
-  Added png_ptr->process_mode = PNG_READ_IDAT_MODE in png_push_read_chunk
-    after recognizing the IDAT chunk, which avoids an infinite loop while
-    reading a datastream whose first IDAT chunk is of zero-length.
-    This fixes CERT VU#684412 and CVE-2014-0333.
-  Don't recognize known sRGB profiles as sRGB if they have been hacked,
-    but don't reject them and don't issue a copyright violation warning.
-  Minor editing of contrib/arm-neon/README and contrib/examples/*.c
-  Moved some documentation from png.h to libpng.3 and libpng-manual.txt
-
-Version 1.7.0beta33 [February 27, 2014]
-  Fixed typos in the manual and in scripts/pnglibconf.dfa (CFLAGS -> CPPFLAGS
-    and PNG_USR_CONFIG -> PNG_USER_CONFIG).
-
-Version 1.7.0beta34 [March 17, 2014]
-  Treat CRC error handling with png_set_crc_action(), instead of with
-    png_set_benign_errors(), which has been the case since libpng-1.6.0beta18.
-  Use "if (value != 0)" instead of "if (value)" consistently.
-  Changed ZlibSrcDir from 1.2.5 to 1.2.8 in projects/vstudio.
-  Moved configuration information from the manual to the INSTALL file.
-
-Version 1.7.0beta35 [August 6, 2014]
-  Removed #if/#else/#endif from inside two pow() calls in pngvalid.c because
-    they were handled improperly by Portland Group's PGI-14.1 - PGI-14.3
-    when using its "__builtin_pow()" function.
-  Silence 'unused parameter' build warnings (Cosmin).
-  $(CP) is now used alongside $(RM_F).  Also, use 'copy' instead
-    of 'cp' where applicable, and applied other minor makefile changes.
-  Don't warn about invalid dimensions exceeding user limits.
-  Allow an easy replacement of the default pre-built configuration
-    header with a custom header, via the make PNGLIBCONF_H_PREBUILT
-    macro.
-  Fixed a typo in pngrutil.c, introduced in libpng-1.5.6, that interferes
-    with "blocky" expansion of sub-8-bit interlaced PNG files (Eric Huss).
+Version 1.6.13beta03 [August 3, 2014]
  Removed scripts/makefile.elf. It has not worked since libpng-1.5.0beta14
    due to elimination of the PNG_FUNCTION_EXPORT and PNG_DATA_EXPORT
    definitions from pngconf.h.
  Ensure that CMakeLists.txt makes the target "lib" directory before making
    symbolic link into it (SourceForge bug report #226 by Rolf Timmermans).
-  Added opinion that the ECCN (Export Control Classification Number) for
-    libpng is EAR99 to the README file.

-Version 1.7.0beta36 [September 27, 2014]
-  Updated scripts/makefiles from libpng-1.6.13beta04.
-  Minor updates to the manual from libpng-1.6.14beta04.
-  Fixed incorrect handling of the iTXt compression flag in pngrutil.c
-    (bug report by Shunsaku Hirata).  Bug was introduced in libpng-1.6.0.
-
-Version 1.7.0beta37 [September 28, 2014]
-  Merged scripts/*, pngvalid.c and pngfix.c with libpng-1.6.14beta04.
-
-Version 1.7.0beta38 [October 17, 2014]
-  Added "option READ_iCCP enables READ_COMPRESSED_TEXT" to pnglibconf.dfa
-  Removed unused "text_len" parameter from private function png_write_zTXt().
-  Conditionally compile some code in png_deflate_claim(), when
-    PNG_WARNINGS_SUPPORTED and PNG_ERROR_TEXT_SUPPORTED are disabled.
-  Replaced repeated code in pngpread.c with PNG_PUSH_SAVE_BUFFER_IF_FULL.
-  Added "chunk iTXt enables TEXT" and "chunk zTXt enables TEXT"
-    to pnglibconf.dfa.
-  Removed "option READ_COMPRESSED_TEXT enables READ_TEXT" from pnglibconf.dfa,
-    to make it possible to configure a libpng that supports iCCP but not TEXT.
-  Removed "option WRITE_COMPRESSED_TEXT enables WRITE_TEXT" from pnglibconf.dfa
-  Only mark text chunks as written after successfully writing them.
-
-Version 1.7.0beta39 [November 1, 2014]
-  Ported cosmetic changes from libpng-1.6.15beta02.
-
-Version 1.7.0beta40 [November 6, 2014]
-  Made a one-line revision to configure.ac to support ARM on aarch64
-    (bug report by Marcin Juszkiewicz, fix by John Bowler).
-  Use png_get_libpng_ver(NULL) instead of PNG_LIBPNG_VER_STRING in
-    example.c, pngtest.c, and applications in the contrib directory.
-  Avoid out-of-bounds memory access in png_user_version_check().
-  Simplified and future-proofed png_user_version_check().
-  Fixed GCC unsigned int->float warnings. Various versions of GCC
-    seem to generate warnings when an unsigned value is implicitly
-    converted to double. This is probably a GCC bug but this change
-    avoids the issue by explicitly converting to (int) where safe.
-  Free all allocated memory in pngimage. The file buffer cache was left
-    allocated at the end of the program, harmless but it causes memory
-    leak reports from clang.
-  Fixed array size calculations to avoid warnings. At various points
-    in the code the number of elements in an array is calculated using
-    sizeof.  This generates a compile time constant of type (size_t) which
-    is then typically assigned to an (unsigned int) or (int). Some versions
-    of GCC on 64-bit systems warn about the apparent narrowing, even though
-    the same compiler does apparently generate the correct, in-range,
-    numeric constant.  This adds appropriate, safe, casts to make the
-    warnings go away.
-
-Version 1.7.0beta41 [November 7, 2014]
-  Added #ifdef PNG_16BIT_SUPPORTED/#endif around png_log16bit() and
-    png_do_swap().
-  Changed all "#endif /* PNG_FEATURE_SUPPORTED */" to "#endif /* FEATURE */"
-
-Version 1.7.0beta42 [November 20, 2014]
-  The macros passed in the command line to Borland make were ignored if
-    similarly-named macros were already defined in makefiles. This behavior
-    is different from POSIX make and other make programs.  Surround the
-    macro definitions with ifndef guards (Cosmin).
-  Added "-D_CRT_SECURE_NO_WARNINGS" to CFLAGS in scripts/makefile.vcwin32.
-  Removed the obsolete $ARCH variable from scripts/makefile.darwin.
-  Merged clang no-warning fix from libpng-1.6.13: png_digit was defined
-    but never used in pngerror.c.
-
-Version 1.7.0beta43 [December 18, 2014]
-  Added ".align 2" to arm/filter_neon.S to support old GAS assemblers that
-    don't do alignment correctly.
-  Revised Makefile.am and scripts/*.dfn to work with MinGW/MSYS;
-    renamed scripts/*.dfn to scripts/*.c (Bob Friesenhahn and John Bowler).
-  Quiet a "comparison always true" warning in pngstest.c (John Bowler).
-
-Version 1.7.0beta44 [December 23, 2014]
-  Restored a test on width that was removed from png.c at libpng-1.6.9
-    (Bug report by Alex Eubanks, CVE-2015-0973).
-  Fixed an overflow in png_combine_row() with very wide interlaced images
-    (Bug report and fix by John Bowler, CVE-2014-9495).
-  Corrected the width limit calculation in png_check_IHDR().
-  Removed extraneous handling of PNG_SAFE_LIMITS_SUPPORTED from pngconf.h
-
-Version 1.7.0beta45 [December 28, 2014]
-  Eliminated the PNG_SAFE_LIMITS macro and restored the 1-million-column
-    and 1-million-row default limits in pnglibconf.dfa, that can be reset
-    by the user at build time or run time.  This provides a more robust
-    defense against DOS and as-yet undiscovered overflows.
-  Removed user limits from pngfix. Also pass NULL pointers to
-    png_read_row to skip the unnecessary row de-interlace stuff.
-  Added testing of png_set_packing() to pngvalid.c
-
-Version 1.7.0beta46 [January 2, 2015]
-  Regenerated configure scripts in the tar distributions with libtool-2.4.4
-  Implement previously untested cases of libpng transforms in pngvalid.c
-  Fixed byte order in 2-byte filler, in png_do_read_filler().
-  Allow user to call png_get_IHDR() with NULL arguments (Reuben Hawkins).
-
-Version 1.7.0beta47 [January 29, 2015]
-  Made the check for out-of-range values in png_set_tRNS() detect
-    values that are exactly 2^bit_depth, and work on 16-bit platforms.
-  Added PNG_SKIP_sRGB_CHECK_PROFILE choice for png_set_option().
-  Report all IHDR errors before exiting png_check_IHDR().
-  Merged some parts of libpng-1.6.17beta01 and libpng-1.7.0beta47.
-  Added #ifndef __COVERITY__ where needed in png.c, pngrutil.c and
-    pngset.c to avoid warnings about dead code.
-
-Version 1.7.0beta48 [February 7, 2015]
-  Work around one more Coverity-scan dead-code warning.
-  Do not build png_product2() when it is unused.
-
-Version 1.7.0beta49 [February 11, 2015]
-  Combined sub_row, up_row, avg_row, and paeth_row buffers into a
-    single try_row buffer.
-  Added PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED macro, on by default.
-  Consolidated redundant code in pngwutil.c
-  Deal with integer overflow of sum in pngwutil.c
-
-Version 1.7.0beta50 [February 15, 2015]
-  Combined sub_row, up_row, avg_row, and paeth_row buffers into a
-    single try_row buffer and in cases where two or more of those are
-    being tested, a second tst_row buffer.  This improves CPU speed
-    over that achieved by libpng-1.7.0beta49.
-
-Version 1.7.0beta51 [February 17, 2015]
-  Combined similar parts of png_write_find_filter() into a png_increase_lmins()
-    function.
-  Display user limits in the output from pngtest.
-  Replaced test for harmless integer overflow (wraparound) in pngwutil.c
-    with a method that prevents overflow and does not increase cpu usage
-    significantly.
-
-Version 1.7.0beta52 [February 21, 2015]
-  Added information about setjmp/simplified API interaction in the
-    manual page and INSTALL file. Added information about using
-    row_pointers with a single height*width*bpp allocated block
-  Rebuilt configure scripts with automake-1.15 and libtool-2.4.6
+Version 1.6.13beta04 [August 8, 2014]
+  Added opinion about the ECCN (Export Control Classification Number) for
+    libpng being EAR99 to README
+  Eliminated use of "$<" in makefiles, when copying $PNGLIBCONF_H_PREBUILT.
+    This does not work on some versions of make; bug introduced in libpng
+    version 1.6.11.

 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
--- a/711
+++ b/711
@@ -1,4 +1,4 @@
-#if 0
+
 CHANGES - changes for libpng

 Version 0.2
@@ -3780,7 +3780,8 @@ Version 1.5.7 [December 15, 2011]

 Version 1.6.0beta01 [December 15, 2011]
  Removed machine-generated configure files from the GIT repository (they will
-    continue to appear in the tarball distributions).
+    continue to appear in the tarball distributions and in the libpng15 and
+    earlier GIT branches).
  Restored the new 'simplified' API, which was started in libpng-1.5.7beta02
    but later deleted from libpng-1.5.7beta05.
  Added example programs for the new 'simplified' API.
@@ -4307,79 +4308,24 @@ Version 1.6.0beta32 [November 25, 2012]
  Fixed error checking in the simplified write API (Olaf van der Spek)
  Made png_user_version_check() ok to use with libpng version 1.10.x and later.

-Version 1.6.0beta33 [December 10, 2012]
+Version 1.6.0beta33 [December 15, 2012]
  Fixed typo in png.c (PNG_SET_CHUNK_MALLOC_MAX should be PNG_CHUNK_MALLOC_MAX)
    that causes the MALLOC_MAX limit not to work (John Bowler)
  Change png_warning() to png_app_error() in pngwrite.c and comment the
    fall-through condition.
  Change png_warning() to png_app_warning() in png_write_tRNS().
+  Rearranged the ARM-NEON optimizations: Isolated the machine specific code
+    to the hardware subdirectory and added comments to pngrutil.c so that
+    implementors of other optimizations know what to do.
+  Fixed cases of unquoted DESTDIR in Makefile.am
+  Rebuilt Makefile.in, etc., with autoconf-2.69 and automake-1.12.5.

-Version 1.7.0alpha01 [December 15, 2012]
-  Started 1.7.0 branch from libpng-1.6.0beta33.
-  Made 8-bit compose and rgb_to_grayscale accuracy improvements.  These
-    changes cause 16-bit arithmetic to be used for 8-bit data in the gamma
-    corrected compose and grayscale operations.  The arithmetic errors have
-    three sources all of which are fixed in this commit:
-    1) 8-bit linear calculations produce massive errors for lower intensity
-       values.
-    2) The old 16-bit "16 to 8" gamma table code erroneously wrote the lowest
-       output value into a table entry which corresponded to multiple output
-       values (so where the value written should have been the closest to the
-       transformed input value.)
-    3) In a number of cases the code to access the 16-bit table did not round;
-       it did a simple shift, which was wrong and made the side effects of (2)
-       even worse.
-  The new gamma code does not have the 16-to-8 problem at the cost of slightly
-    more calculations and the algorithm used to minimize the number of
-    calculations has been extended to all the 16-bit tables; it has advantages
-    for any significant gamma correction.
-  Rearranged png_struct, remove unused members, change png_set_filter handling
-    png_struct members rearranged - partly to reorder to avoid packing, partly
-    to put frequently accessed members at the start and partly to make
-    the grouping more clear. png_set_filter code has been rewritten and the
-    code shared with png_write_start_row moved to a common function.  Comments
-    in png.h have been made more clear. Minor fixes to
-    contrib/libtests/timepng.c and some of the png_*_tRNS logic, including
-    more error detection in png_set_tRNS.
-  Cleaned up USER_LIMITS feature, removing members from png_struct when not
-    required.
-  Rearranged ARM-NEON optimizations to isolate the machine specific code to
-    the hardware subdirectory, and add comments to pngrutil.c so that
-    implementors of other optimizations will know what to do.
-  Fixed cases of unquoted DESTDIR in Makefile.am.
-  Rebuilt Makefile.in, configure, etc., with autoconf-2.69 and automake-1.12.5.
-
-Version 1.7.0alpha02 [December 17, 2012]
-  Removed functions that were deprecated in libpng-1.6.0:
-    png_reset_zstream(), png_info_init_3(), png_data_freer() and its
-    associated flags, png_malloc_default, and png_free_default.
-  Removed some duplicated lines from contrib/tools/scale.c and png.c.
-  Changed some instances of png_warning() to png_app_error().
-  Updated some left over "1.6.0beta32" in code sources.
-  Fixed a "png_structp" prototype (should be png_structrp) in arm_init.c
-  Updated the version-number hack in pngvalid.c
-  
-Version 1.7.0alpha03 [December 19, 2012]
-  Cleaned up and enhanced the configure option; libpng now correctly
-    links and tests against zlib with a prefix; tests have been clarified; and
-    irrelevant or obsolete things (as defined by the autotools man page) have
-    been removed.
-  Documented new PNG_ABORT behavior in the manual and commentary in pngerror.c
+Version 1.6.0beta34 [December 19, 2012]
  Cleaned up whitespace in the synopsis portion of the manpage "libpng.3"
-  Fixed previous support for Z_PREFIX in configure builds, corrected sCAL APIs;
-    some of these use floating point arithmetic so they need to be disabled if
-    floating point arithmetic is switched off.  This is a quiet API change -
-    previously it appeared that the APIs were supported if fixed point
-    arithmetic was used internally, however they required certain APIs (floor,
-    modf, frexp, atof) that are part of C floating point support. Changed
-    png_fixed and the gamma code specific version of the same to avoid floor(),
-    which may be a library function (not an intrinsic). Removed unused #if 0
-    code.
  Disassembled the version number in scripts/options.awk (necessary for
    building on SunOs).

-Version 1.7.0alpha04 [December 23, 2012]
-  Added scripts/makefile.msys contributed by Christopher M. Wheeler
+Version 1.6.0beta35 [December 23, 2012]
  Made default Zlib compression settings be configurable. This adds #defines to
    pnglibconf.h to control the defaults.
  Fixed Windows build issues, enabled ARM compilation. Various warnings issued
@@ -4388,88 +4334,82 @@ Version 1.7.0alpha04 [December 23, 2012]
    Microsoft) and ARM compilation is made possible by deleting the check for
    x86. The test programs cannot be run because they are not signed.

-Version 1.7.0alpha05 [December 24, 2012]
+Version 1.6.0beta36 [January 2, 2013]
  Discontinued distributing libpng-1.x.x.tar.bz2.
  Discontinued distributing libpng-1.7.0-1.6.0-diff.txt and similar.
-
-Version 1.7.0alpha06 [January 1, 2013]
+  Rebuilt configure with autoconf-2.69 (inadvertently not done in beta33)
  Fixed 'make distcheck' on SUN OS - libpng.so was not being removed

-Version 1.7.0alpha07 [January 10, 2013]
+Version 1.6.0beta37 [January 10, 2013]
  Fixed conceivable but difficult to repro overflow. Also added two test
    programs to generate and test a PNG which should have the problem.

-Version 1.7.0alpha08 [January 17, 2013]
-  Corrected previous attempt at overflow detection in png_set_unknown_chunks()
+Version 1.6.0beta39 [January 19, 2013]
+  Again corrected attempt at overflow detection in png_set_unknown_chunks()
  (CVE-2013-7353).  Added overflow detection in png_set_sPLT() and
  png_set_text_2() (CVE-2013-7354).

-Version 1.7.0alpha09 [January 21, 2013]
-  Pulled changes to multi-chunk handling from libpng-1.6.0beta40.
+Version 1.6.0beta40 [January 20, 2013]
+  Use consistent handling of overflows in text, sPLT and unknown png_set_* APIs

-Version 1.7.0alpha10 [February 5, 2013]
-  Make symbol prefixing work with the ARM neon optimizations. Also
-    allow pngpriv.h to be included for preprocessor definitions only, so
-    it can be used in non-C/C++ files.
+Version 1.6.0rc01 [January 26, 2013]
+  No changes.
+
+Version 1.6.0rc02 [February 4, 2013]
  Added png_get_palette_max() function.
-  Changed png_size_t to size_t throughout headers, make sRGB check numbers
-    consistent.
-  Fixed ARM support (Mans Rullgard).
-  Removed stray out-of-order #endif and #ifdef (Mans Rullgard).
-  Ported libpng 1.5 options.awk/dfn file handling to 1.7, fixed one bug.
-  Rebuilt Makefile.in, configure, etc., with autoconf-2.69 and automake-1.13.
-  Minor fixes to assembler changes, verified with a dummy .S file
-  Removed cc -E workround, corrected png_get_palette_max API. Tested on
-    SUN OS cc 5.9, which demonstrates the tokenization problem previously
-    avoided by using /lib/cpp.  Since all .dfn output is now protected
-    in double quotes unless it is to be macro substituted the fix should work
-    everywhere.

-Version 1.7.0beta01 [February 15, 2013]
-  Enable parallel tests and rearrange TESTS order to take advantage of
-    the massive speed improvements use a make capable of parallel builds
-    on a multi-CPU machine and pass the right arguments to make (-j10000
-    for GNU make) to get the build to run in parallel.
-  Fixed previous support for Z_PREFIX in configure builds, corrected
-    sCAL APIs; some of these use floating point arithmetic so need to be
-    disabled if floating point arithmetic is switched off.  This is a quiet API
-    change - previously it appeared that the APIs were supported if fixed point
-    arithmetic was used internally, however they required certain APIs (floor,
-    modf, frexp, atof) that are part of C floating point support. Changed
-    png_fixed and the gamma code specific version of the same to avoid floor(),
-    which may be a library function (not an intrinsic). Removed unused #if 0
-    code.
-  Fixed make distcheck to skip over the test result files. They were
-    being included because the whole of the 'tests' directory is included,
-    fixed to just include the actual test files and tests/pngstest.  Also
-    reverted the previous erroneous change to remove the ${srcdir} from the
-    front of contrib, scripts, projects and added an explanation of what is
-    going on to Makefile.am
-  Fixed missing dependency in --prefix builds. The intermediate
-    internal 'prefix.h' file can only be generated correctly after pnglibconf.h,
-    however the dependency was not in Makefile.am.  The symptoms are
-    unpredictable depending on the order make chooses to build pngprefix.h and
-    pnglibconf.h, often the error goes unnoticed because there is a system
-    pnglibconf.h to use instead.
-  Accept "," as a separator in pnglibconf.dfa and allow for
-    continuation lines. This adds to the syntax of "option" and "chunk" lines,
-    allowing the elements to be separated by a "," at the end of an element and
-    interpreting a "," at end of line as a continuation - so the following line
-    is read.  The new syntax is optional and solely provided for readability.
+Version 1.6.0rc03 [February 5, 2013]
+  Fixed the png_get_palette_max API.
+
+Version 1.6.0rc04 [February 7, 2013]
+  Turn serial tests back on (recently turned off by autotools upgrade).
+
+Version 1.6.0rc05 [February 8, 2013]
+  Update manual about png_get_palette_max().
+
+Version 1.6.0rc06 [February 9, 2013]
+  Fixed missing dependency in --prefix builds The intermediate
+    internal 'prefix.h' file can only be generated correctly after
+    pnglibconf.h, however the dependency was not in Makefile.am.  The
+    symptoms are unpredictable depending on the order make chooses to
+    build pngprefix.h and pnglibconf.h, often the error goes unnoticed
+    because there is a system pnglibconf.h to use instead.
+
+Version 1.6.0rc07 [February 10, 2013]
  Enclosed the new png_get_palette_max in #ifdef PNG_GET_PALETTE_MAX_SUPPORTED
    block, and revised pnglibconf.h and pnglibconf.h.prebuilt accordingly.

-Version 1.7.0beta02 [February 18, 2013]
+Version 1.6.0rc08 [February 10, 2013]
+  Fix typo in png.h #ifdef
+
+Version 1.6.0 [February 14, 2013]
+  No changes.
+
+Version 1.6.1beta01 [February 16, 2013]
+  Made symbol prefixing work with the ARM neon optimizations. Also allow
+    pngpriv.h to be included for preprocessor definitions only, so it can
+    be used in non-C/C++ files. Back ported from libpng 1.7.
+  Made sRGB check numbers consistent.
+  Ported libpng 1.5 options.awk/dfn file handling to 1.6, fixed one bug.
+  Removed cc -E workround, corrected png_get_palette_max API Tested on
+    SUN OS cc 5.9, which demonstrates the tokenization problem previously
+    avoided by using /lib/cpp.  Since all .dfn output is now protected in
+    double quotes unless it is to be macro substituted the fix should
+    work everywhere.
+  Enabled parallel tests - back ported from libpng-1.7.
+  scripts/pnglibconf.dfa formatting improvements back ported from libpng17.
  Fixed a race condition in the creation of the build 'scripts' directory
    while building with a parallel make.
  Use approved/supported Android method to check for NEON, use Linux/POSIX
    1003.1 API to check /proc/self/auxv avoiding buffer allocation and other
    library calls (ported from libpng15).
+
+Version 1.6.1beta02 [February 19, 2013]
  Use parentheses more consistently in "#if defined(MACRO)" tests.
  Folded long lines.
-
-Version 1.7.0beta03 [February 22, 2013]
  Reenabled code to allow zero length PLTE chunks for MNG.
+
+Version 1.6.1beta03 [February 22, 2013]
  Fixed ALIGNED_MEMORY support.
  Allow run-time ARM NEON checking to be disabled. A new configure option:
    --enable-arm-neon=always will stop the run-time checks. New checks
@@ -4478,28 +4418,27 @@ Version 1.7.0beta03 [February 22, 2013]
    for it on then the build will fail if it can't be done.)
  Updated the INSTALL document.

-Version 1.7.0beta04 [February 27, 2013]
+Version 1.6.1beta04 [February 27, 2013]
  Revised INSTALL to recommend using CPPFLAGS instead of INCLUDES.
  Revised scripts/makefile.freebsd to respect ZLIBLIB and ZLIBINC.
  Revised scripts/dfn.awk to work with the buggy MSYS awk that has trouble
    with CRLF line endings.

-Version 1.7.0beta05 [March 5, 2013]
+Version 1.6.1beta05 [March 1, 2013]
  Avoid a possible memory leak in contrib/gregbook/readpng.c
-  Changed user chunk callback API to respect global and per chunk defaults.
-    Previously a return of 0 from a user chunk callback would result in the
-    chunk being saved (if this was safe, even if the chunk was unsafe-to-copy);
-    this change respects the defaults set by the application, so unknown chunks
-    can be discarded by default and known-safe ones preserved.
+
+Version 1.6.1beta06 [March 4, 2013]
+  Better documentation of unknown handling API interactions.
  Corrected Android builds and corrected libpng.vers with symbol
-    prefixing. This adds an API to set optimization options externally,
+    prefixing This adds an API to set optimization options externally,
    providing an alternative and general solution for the non-portable
    run-time tests used by the ARM Neon code.  It also makes those tests
-    compile and link on Android.  The order of settings vs options in
-    pnglibconf.h is reversed to allow settings to depend on options and
-    options can now set (or override) the defaults for settings.
+    compile and link on Android.
+  The order of settings vs options in pnglibconf.h is reversed to allow
+    settings to depend on options and options can now set (or override) the
+    defaults for settings.

-Version 1.7.0beta06 [March 13, 2013]
+Version 1.6.1beta07 [March 7, 2013]
  Corrected simplified API default gamma for color-mapped output, added
    a flag to change default. In 1.6.0 when the simplified API was used
    to produce color-mapped output from an input image with no gamma
@@ -4512,6 +4451,8 @@ Version 1.7.0beta06 [March 13, 2013]
    application/user to specify that 16-bit files contain sRGB data
    rather than the default linear.
  Fixed bugs in the pngpixel and makepng test programs.
+
+Version 1.6.1beta08 [March 7, 2013]
  Fixed CMakelists.txt to allow building a single variant of the library
    (Claudio Bley):
  Introduced a PNG_LIB_TARGETS variable that lists all activated library
@@ -4523,11 +4464,19 @@ Version 1.7.0beta06 [March 13, 2013]
    first argument. When symlinking the filename component of that path is
    determined and used as the link target.
  Use copy_if_different in the CREATE_SYMLINK macro.
+
+Version 1.6.1beta09 [March 13, 2013]
  Eliminated two warnings from the Intel C compiler. The warnings are
    technically valid, although a reasonable treatment of division would
    show it to be incorrect.

-Version 1.7.0beta07 [April 14, 2013]
+Version 1.6.1rc01 [March 21, 2013]
+  No changes.
+
+Version 1.6.1 [March 28, 2013]
+  No changes.
+
+Version 1.6.2beta01 [April 14, 2013]
  Updated documentation of 1.5.x to 1.6.x changes in iCCP chunk handling.
  Fixed incorrect warning of excess deflate data. End condition - the
    warning would be produced if the end of the deflate stream wasn't read
@@ -4539,45 +4488,46 @@ Version 1.7.0beta07 [April 14, 2013]
  Corrected a misplaced closing bracket in contrib/libtests/pngvalid.c
    (Flavio Medeiros).
  Corrected length written to uncompressed iTXt chunks (Samuli Suominen).
+    Bug was introduced in libpng-1.6.0.

-Version 1.7.0beta08 [April 18, 2013]
+Version 1.6.2rc01 [April 18, 2013]
  Added contrib/tools/fixitxt.c, to repair the erroneous iTXt chunk length
    written by libpng-1.6.0 and 1.6.1.
  Disallow storing sRGB information when the sRGB is not supported.

-Version 1.7.0beta09 [April 24, 2013]
-  Exposed PNG chunk types in png.h
-  Modified png_uint_32 macros/code to make as few assumptions as possible
-    about the hardware.
+Version 1.6.2rc02 [April 18, 2013]
+  Merge pngtest.c with libpng-1.7.0
+
+Version 1.6.2rc03 [April 22, 2013]
+  Trivial spelling cleanup.
+
+Version 1.6.2rc04 and 1.6.2rc05 [omitted]
+
+Version 1.6.2rc06 [April 24, 2013]
+  Reverted to version 1.6.2rc03.  Recent changes to arm/neon support
+    have been ported to libpng-1.7.0beta09 and will reappear in version
+    1.6.3beta01.
+
+Version 1.6.2 [April 25, 2013]
+  No changes.
+
+Version 1.6.3beta01 [April 25, 2013]
  Revised stack marking in arm/filter_neon.S and configure.ac.
  Ensure that NEON filter stuff is completely disabled when switched 'off'.
    Previously the ARM NEON specific files were still built if the option
    was switched 'off' as opposed to being explicitly disabled.

-Version 1.7.0beta10 [April 24, 2013]
-  Attempt to fix the PNG_ARM_NEON configuration mess.
+Version 1.6.3beta02 [April 26, 2013]
+  Test for 'arm*' not just 'arm' in the host_cpu configure variable.
+  Rebuilt the configure scripts.

-Version 1.7.0beta11 [April 26, 2013]
-  Test for 'arm*', not just 'arm' in the host_cpu configure variable.
-
-Version 1.7.0beta12 [April 30, 2013]
-  Added png_app_warning for out-of-range unknown chunk index in
-    png_set_unknown_chunk_location().
-  Expanded manual paragraph about writing private chunks.
+Version 1.6.3beta03 [April 30, 2013]
+  Expanded manual paragraph about writing private chunks, particularly
+    the need to call png_set_keep_unknown_chunks() when writing them.
  Avoid dereferencing NULL pointer possibly returned from
     png_create_write_struct() (Andrew Church).

-Version 1.7.0beta13 [May 12, 2013]
-  Revised contrib/pngminim/*/makefile to generate pnglibconf.h with the
-    right zlib header files.
-  Separated CPPFLAGS and CFLAGS in contrib/pngminim/*/makefile
-  Updated contrib/pngminus/pnm2png.c (Paul Stewart):
-    Check for EOF
-    Ignore "#" delimited comments in input file to pnm2png.c.
-    Fixed whitespace handling
-    Added a call to png_set_packing()
-    Initialize dimension values so if sscanf fails at least we have known
-      invalid values.
+Version 1.6.3beta05 [May 9, 2013]
  Calculate our own zlib windowBits when decoding rather than trusting the
    CMF bytes in the PNG datastream.
  Added an option to force maximum window size for inflating, which was
@@ -4589,6 +4539,15 @@ Version 1.7.0beta13 [May 12, 2013]
    only works with libpng versions that can be made to reliably fail when
    the deflate data contains an out-of-window reference.  This means only
    1.6 and later.
+  Fixed gnu issues: g++ needs a static_cast, gcc 4.4.7 has a broken warning
+    message which it is easier to work round than ignore.
+  Updated contrib/pngminus/pnm2png.c (Paul Stewart):
+    Check for EOF
+    Ignore "#" delimited comments in input file to pnm2png.c.
+    Fixed whitespace handling
+    Added a call to png_set_packing()
+    Initialize dimension values so if sscanf fails at least we have known
+      invalid values.
  Attempt to detect configuration issues with png-fix-too-far-back, which
    requires both the correct libpng and the correct zlib to function
    correctly.
@@ -4596,11 +4555,21 @@ Version 1.7.0beta13 [May 12, 2013]
  Added information in the documentation about problems with and fixes for
    the bad CRC and bad iTXt chunk situations.

-Version 1.7.0beta14 [June 8, 2013]
+Version 1.6.3beta06 [May 12, 2013]
+  Allow contrib/pngminus/pnm2png.c to compile without WRITE_INVERT and
+    WRITE_PACK supported (writes error message that it can't read P1 or
+    P4 PBM files).
+  Improved png-fix-too-far-back usage message, added --suffix option.
+  Revised contrib/pngminim/*/makefile to generate pnglibconf.h with the
+    right zlib header files.
+  Separated CPPFLAGS and CFLAGS in contrib/pngminim/*/makefile
+
+Version 1.6.3beta07 [June 8, 2013]
  Removed a redundant test in png_set_IHDR().
  Added set(CMAKE_CONFIGURATION_TYPES ...) to CMakeLists.txt (Andrew Hundt)
  Deleted set(CMAKE_BUILD_TYPE) block from CMakeLists.txt
-  Enclose the prototypes for the simplified write API in #ifdef STDIO/#endif
+  Enclose the prototypes for the simplified write API in
+    #ifdef PNG_STDIO_SUPPORTED/#endif
  Make ARM NEON support work at compile time (not just configure time).
    This moves the test on __ARM_NEON__ into pngconf.h to avoid issues when
    using a compiler that compiles for multiple architectures at one time.
@@ -4620,50 +4589,79 @@ Version 1.7.0beta14 [June 8, 2013]
    the confusion that would result by declaring the init function even when
    it is not used, so that it will always get prefixed.

-Version 1.7.0beta15 [June 18, 2013]
+Version 1.6.3beta08 [June 18, 2013]
  Revised libpng.3 so that "doclifter" can process it.

-Version 1.7.0beta16 [July 5, 2013]
+Version 1.6.3beta09 [June 27, 2013]
  Revised example.c to illustrate use of PNG_DEFAULT_sRGB and PNG_GAMMA_MAC_18
    as parameters for png_set_gamma().  These have been available since
    libpng-1.5.4.
  Renamed contrib/tools/png-fix-too-far-back.c to pngfix.c and revised it
    to check all compressed chunks known to libpng.
-  Updated documentation to show default behavior of benign errors correctly.
-  Added perfect hash code generation for lists of PNG chunks. This is
-    a work in progress; checked in for use in pngfix.c
-  Ported ARM no-read patch from libpng16.
-  Ported pngfix.c patches from libpng16.

-Version 1.7.0beta17 [August 21, 2013]
+Version 1.6.3beta10 [July 5, 2013]
+  Updated documentation to show default behavior of benign errors correctly.
+  Only compile ARM code when PNG_READ_SUPPORTED is defined.
+  Fixed undefined behavior in contrib/tools/pngfix.c and added new strip
+    option. pngfix relied on undefined behavior and even a simple change from
+    gcc to g++ caused it to fail.  The new strip option 'unsafe' has been
+    implemented and is the default if --max is given.  Option names have
+    been clarified, with --strip=transform now stripping the bKGD chunk,
+    which was stripped previously with --strip=unused.
+  Added all documented chunk types to pngpriv.h
+  Unified pngfix.c source with libpng17.
+
+Version 1.6.3rc01 [July 11, 2013]
+  No changes.
+
+Version 1.6.3 [July 18, 2013]
  Revised manual about changes in iTXt chunk handling made in libpng-1.6.0.
  Added "/* SAFE */" comments in pngrutil.c and pngrtran.c where warnings
    may be erroneously issued by code-checking applications.
+
+Version 1.6.4beta01 [August 21, 2013]
  Added information about png_set_options() to the manual.
  Delay calling png_init_filter_functions() until a row with nonzero filter
    is found.

-Version 1.7.0beta18 [September 16, 2013]
+Version 1.6.4beta02 [August 30, 2013]
  Fixed inconsistent conditional compilation of png_chunk_unknown_handling()
    prototype, definition, and usage.  Made it depend on
    PNG_HANDLE_AS_UNKNOWN_SUPPORTED everywhere.

-Version 1.7.0beta19 [September 30, 2013]
-  Reverted the change to unknown handling #defines; the change breaks 'NOREAD'
-    builds.
-  Fixed default behavior of ARM_NEON_API. If the ARM NEON API option is
-    compiled without the CHECK option it defaulted to on, not off.
-  Catch up with recent libpng16 changes; unknown handling and spelling
-    corrections
+Version 1.6.4rc01 [September 5, 2013]
+  No changes.
+
+Version 1.6.4 [September 12, 2013]
+  No changes.
+
+Version 1.6.5 [September 14, 2013]
+  Removed two stray lines of code from arm/arm_init.c.
+
+Version 1.6.6 [September 16, 2013]
+  Removed two stray lines of code from arm/arm_init.c, again.
+
+Version 1.6.7beta01 [September 30, 2013]
+  Revised unknown chunk code to correct several bugs in the NO_SAVE_/NO_WRITE
+    combination
+  Allow HANDLE_AS_UNKNOWN to work when other options are configured off. Also
+    fixed the pngminim makefiles to work when $(MAKEFLAGS) contains stuff
+    which terminates the make options (as by default in recent versions of
+    Gentoo).
  Avoid up-cast warnings in pngvalid.c. On ARM the alignment requirements of
    png_modifier are greater than that of png_store and as a consequence
    compilation of pngvalid.c results in a warning about increased alignment
-    requirements because of the bare cast to (png_modifier*).  The code is
-    safe, because the pointer is known to point to a stack allocated
-    png_modifier, but this change avoids the warning.
-  Fixed some grammatical changes and updated the png chunks list.
+    requirements because of the bare cast to (png_modifier*). The code is safe,
+    because the pointer is known to point to a stack allocated png_modifier,
+    but this change avoids the warning.
+  Fixed default behavior of ARM_NEON_API. If the ARM NEON API option was
+    compiled without the CHECK option it defaulted to on, not off.
+  Check user callback behavior in pngunknown.c. Previous versions compiled
+    if SAVE_UNKNOWN was not available but did nothing since the callback
+    was never implemented.
+  Merged pngunknown.c with 1.7 version and back ported 1.7 improvements/fixes

-Version 1.7.0beta20 [October 13, 2013]
+Version 1.6.7beta02 [October 12, 2013]
  Made changes for compatibility with automake 1.14:
    1) Added the 'compile' program to the list of programs that must be cleaned
       in autogen.sh
@@ -4689,13 +4687,15 @@ Version 1.7.0beta20 [October 13, 2013]
  Make autogen.sh work with automake 1.13 as well as 1.14. Do this by always
    removing the 1.14 'compile' script but never checking for it.

-Version 1.7.0beta21 [November 2, 2013]
+Version 1.6.7beta03 [October 19, 2013]
  Added ARMv8 support (James Yu <james.yu at linaro.org>).  Added file
    arm/filter_neon_intrinsics.c; enable with -mfpu=neon.
  Revised pngvalid to generate size images with as many filters as it can
    manage, limited by the number of rows.
  Cleaned up ARM NEON compilation handling. The tests are now in pngpriv.h
    and detect the broken GCC compilers.
+
+Version 1.6.7beta04 [October 26, 2013]
  Allow clang derived from older GCC versions to use ARM intrinsics. This
    causes all clang builds that use -mfpu=neon to use the intrinsics code,
    not the assembler code.  This has only been tested on iOS 7. It may be
@@ -4705,14 +4705,17 @@ Version 1.7.0beta21 [November 2, 2013]
    PNG_ARM_NEON_IMPLEMENTATION to the correct value (2 or 1).  This macro
    is undefined by default and the build type is selected in pngpriv.h.

-Version 1.7.0beta22 [November 7, 2013]
+Version 1.6.7rc01 [November 2, 2013]
+  No changes.
+
+Version 1.6.7rc02 [November 7, 2013]
  Fixed #include in filter_neon_intrinsics.c and ctype macros. The ctype char
    checking macros take an unsigned char argument, not a signed char.

-Version 1.7.0beta23 [November 24, 2013]
-  Changed #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED in pngpread.c to
-    #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED to be consistent with
-    what is in pngpriv.h.
+Version 1.6.7 [November 14, 2013]
+  No changes.
+
+Version 1.6.8beta01 [November 24, 2013]
  Moved prototype for png_handle_unknown() in pngpriv.h outside of
    the #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED/#endif block.
  Added "-Wall" to CFLAGS in contrib/pngminim/*/makefile
@@ -4728,13 +4731,28 @@ Version 1.7.0beta23 [November 24, 2013]
    This reverts to the previous 'static' implementation and works round
    the 'unused static function' warning by using PNG_UNUSED().

-Version 1.7.0beta24 [December 15, 2013]
+Version 1.6.8beta02 [November 30, 2013]
  Removed or marked PNG_UNUSED some harmless "dead assignments" reported
    by clang scan-build.
  Changed tabs to 3 spaces in png_debug macros and changed '"%s"m'
    to '"%s" m' to improve portability among compilers.
  Changed png_free_default() to free() in pngtest.c
+
+Version 1.6.8rc01 [December 12, 2013]
  Tidied up pngfix inits and fixed pngtest no-write builds.
+
+Version 1.6.8rc02 [December 14, 2013]
+  Handle zero-length PLTE chunk or NULL palette with png_error()
+    instead of png_chunk_report(), which by default issues a warning
+    rather than an error, leading to later reading from a NULL pointer
+    (png_ptr->palette) in png_do_expand_palette(). This is CVE-2013-6954
+    and VU#650142.  Libpng-1.6.1 through 1.6.7 are vulnerable.
+    Libpng-1.6.0 and earlier do not have this bug.
+
+Version 1.6.8 [December 19, 2013]
+  No changes.
+
+Version 1.6.9beta01 [December 26, 2013]
  Bookkeeping: Moved functions around (no changes). Moved transform
    function definitions before the place where they are called so that
    they can be made static. Move the intrapixel functions and the
@@ -4747,60 +4765,50 @@ Version 1.7.0beta24 [December 15, 2013]
    segment of the DLL by 1208 bytes, about 0.6%. It also simplifies
    maintenance by removing the declarations from pngpriv.h and allowing
    easier changes to the internal interfaces.
-  Handle zero-length PLTE chunk or NULL palette with png_error()
-    instead of png_chunk_report(), which by default issues a warning
-    rather than an error, leading to later reading from a NULL pointer
-    (png_ptr->palette) in png_do_expand_palette(). This is CVE-2013-6954
-    and VU#650142.  Libpng-1.6.1 through 1.6.7 and libpng-1.7.0beta03
-    through 1.7.0beta23 are vulnerable.  Libpng-1.6.0 and earlier do not
-    have the bug.
-
-Version 1.7.0beta25 [December 26, 2013]
-  Merged files with version 1.6.8 that have not changed since then.
  Rebuilt configure scripts with automake-1.14.1 and autoconf-2.69
+    in the tar distributions.

-Version 1.7.0beta26 [January 1, 2014]
-  Added libpng 1.5 checks to pngvalid.c
-  Merged with 1.5 and 1.6 changes to create a single pngvalid.c
-  Added dSIG to chunk list in png.h
+Version 1.6.9beta02 [January 1, 2014]
+  Added checks for libpng 1.5 to pngvalid.c.  This supports the use of
+    this version of pngvalid in libpng 1.5
+  Merged with pngvalid.c from libpng-1.7 changes to create a single
+    pngvalid.c
  Removed #error macro from contrib/tools/pngfix.c (Thomas Klausner).
-  Merged pngrio.c, pngtrans.c, and pngwio.c with libpng-1.6.9
-  Fixed test programs for interlace options. Made pngvalid.c and
-    pngtest.c work correctly when READ_INTERLACING and/or WRITE_INTERLACING
-    are switched off.
-  Changed pngvalid.c to support libpng 1.5, which does not support
-    the PNG_MAXIMUM_INFLATE_WINDOW option, so #define it out when
-    appropriate in pngvalid.c
+  Merged pngrio.c, pngtrans.c, pngwio.c, and pngerror.c with libpng-1.7.0
+  Merged libpng-1.7.0 changes to make no-interlace configurations work
+    with test programs.
+  Revised pngvalid.c to support libpng 1.5, which does not support the
+    PNG_MAXIMUM_INFLATE_WINDOW option, so #define it out when appropriate in
+    pngvalid.c
  Allow unversioned links created on install to be disabled in configure.
    In configure builds 'make install' changes/adds links like png.h
    and libpng.a to point to the newly installed, versioned, files (e.g.
    libpng17/png.h and libpng17.a). Three new configure options and some
    rearrangement of Makefile.am allow creation of these links to be disabled.

-Version 1.7.0beta27 [January 10, 2014]
+Version 1.6.9beta03 [January 10, 2014]
  Removed potentially misleading warning from png_check_IHDR().

-Version 1.7.0beta28 [January 20, 2014]
+Version 1.6.9beta04 [January 20, 2014]
  Updated scripts/makefile.* to use CPPFLAGS (Cosmin).
  Added clang attribute support (Cosmin).

-Version 1.7.0beta29 [January 30, 2014]
-  Quiet an uninitialized memory warning from VS2013 in png_get_png().
+Version 1.6.9rc01 [January 28, 2014]
+  No changes.

-Version 1.7.0beta30 [February 2, 2014]
+Version 1.6.9rc02 [January 30, 2014]
+  Quiet an uninitialized memory warning from VC2013 in png_get_png().
+
+Version 1.6.9 [February 6, 2014]
+
+Version 1.6.10beta01 [February 9, 2014]
+  Backported changes from libpng-1.7.0beta30 and beta31:
  Fixed a large number of instances where PNGCBAPI was omitted from
    function definitions.
-  Added pngimage test program for png_read_png and png_write_png. This
-    is a work-in-progress; no tests are run automatically at present and
-    the program by virtue of exhaustively testing all the transforms is
-    very slow.
-
-Version 1.7.0beta31 [February 6, 2014]
-  Make png_read_png() and png_write_png() prototypes in png.h depend
-    upon PNG_READ_SUPPORTED and PNG_WRITE_SUPPORTED.
+  Added pngimage test program for png_read_png() and png_write_png()
+    with two new test scripts.
  Removed dependence on !PNG_READ_EXPAND_SUPPORTED for calling
    png_set_packing() in png_read_png().
-  Completed full working pngimage test program and added two test scripts.
  Fixed combination of ~alpha with shift. On read invert alpha, processing
    occurred after shift processing, which causes the final values to be
    outside the range that should be produced by the shift. Reversing the
@@ -4811,10 +4819,8 @@ Version 1.7.0beta31 [February 6, 2014]
    the read code to return an invalid sBIT chunk, which might lead to
    application errors or crashes.  Such chunks are now skipped (with
    chunk_benign_error).
-  Restored a line, "c = b;", that was inadvertently deleted from the
-    PAETH filtering code from libpng-1.7.0beta24/pngrutil.c. Deleted
-    the other instance of "c = b;" which is the one that triggered a
-    scan-build warning.
+  Make png_read_png() and png_write_png() prototypes in png.h depend
+    upon PNG_READ_SUPPORTED and PNG_WRITE_SUPPORTED.
  Support builds with unsupported PNG_TRANSFORM_* values.  All of the
    PNG_TRANSFORM_* values are always defined in png.h and, because they
    are used for both read and write in some cases, it is not reliable
@@ -4824,7 +4830,7 @@ Version 1.7.0beta31 [February 6, 2014]
    and it adds corresponding code to pngimage.c to handle such options
    by not attempting to test them.

-Version 1.7.0beta32 [February 26, 2014]
+Version 1.6.10beta02 [February 23, 2014]
  Moved redefines of png_error(), png_warning(), png_chunk_error(),
    and png_chunk_warning() from pngpriv.h to png.h to make them visible
    to libpng-calling applications.
@@ -4841,6 +4847,8 @@ Version 1.7.0beta32 [February 26, 2014]
    it more robust against future programming errors.
  Check for __has_extension before using it in pngconf.h, to
    support older Clang versions (Jeremy Sequoia).
+  Treat CRC error handling with png_set_crc_action(), instead of with
+    png_set_benign_errors(), which has been the case since libpng-1.6.0beta18.
  Use a user warning handler in contrib/gregbook/readpng2.c instead of default,
    so warnings will be put on stderr even if libpng has CONSOLE_IO disabled.
  Added png_ptr->process_mode = PNG_READ_IDAT_MODE in png_push_read_chunk
@@ -4849,174 +4857,120 @@ Version 1.7.0beta32 [February 26, 2014]
    This fixes CERT VU#684412 and CVE-2014-0333.
  Don't recognize known sRGB profiles as sRGB if they have been hacked,
    but don't reject them and don't issue a copyright violation warning.
-  Minor editing of contrib/arm-neon/README and contrib/examples/*.c
-  Moved some documentation from png.h to libpng.3 and libpng-manual.txt

-Version 1.7.0beta33 [February 27, 2014]
+Version 1.6.10beta03 [February 25, 2014]
+  Moved some documentation from png.h to libpng.3 and libpng-manual.txt
+  Minor editing of contrib/arm-neon/README and contrib/examples/*.c
+
+Version 1.6.10rc01 [February 27, 2014]
  Fixed typos in the manual and in scripts/pnglibconf.dfa (CFLAGS -> CPPFLAGS
    and PNG_USR_CONFIG -> PNG_USER_CONFIG).

-Version 1.7.0beta34 [March 17, 2014]
-  Treat CRC error handling with png_set_crc_action(), instead of with
-    png_set_benign_errors(), which has been the case since libpng-1.6.0beta18.
+Version 1.6.10rc02 [February 28, 2014]
+  Removed unreachable return statement after png_chunk_error()
+    in pngrutil.c
+
+Version 1.6.10rc03 [March 4, 2014]
+  Un-deprecated png_data_freer().
+
+Version 1.6.10 [March 6, 2014]
+  No changes.
+
+Version 1.6.11beta01 [March 17, 2014]
  Use "if (value != 0)" instead of "if (value)" consistently.
  Changed ZlibSrcDir from 1.2.5 to 1.2.8 in projects/vstudio.
  Moved configuration information from the manual to the INSTALL file.

-Version 1.7.0beta35 [August 6, 2014]
+Version 1.6.11beta02 [April 6, 2014]
  Removed #if/#else/#endif from inside two pow() calls in pngvalid.c because
    they were handled improperly by Portland Group's PGI-14.1 - PGI-14.3
    when using its "__builtin_pow()" function.
-  Silence 'unused parameter' build warnings (Cosmin).
-  $(CP) is now used alongside $(RM_F).  Also, use 'copy' instead
-    of 'cp' where applicable, and applied other minor makefile changes.
-  Don't warn about invalid dimensions exceeding user limits.
+  Silence 'unused parameter' build warnings (Cosmin Truta).
+  $(CP) is now used alongside $(RM_F).  Also, use 'copy' instead of 'cp'
+    where applicable, and applied other minor makefile changes (Cosmin).
+  Don't warn about invalid dimensions exceeding user limits (Cosmin).
  Allow an easy replacement of the default pre-built configuration
    header with a custom header, via the make PNGLIBCONF_H_PREBUILT
-    macro.
+    macro (Cosmin).
+
+Version 1.6.11beta03 [April 6, 2014]
  Fixed a typo in pngrutil.c, introduced in libpng-1.5.6, that interferes
    with "blocky" expansion of sub-8-bit interlaced PNG files (Eric Huss).
+  Optionally use  __builtin_bswap16() in png_do_swap().
+
+Version 1.6.11beta04 [April 19, 2014]
+  Made progressive reading of interlaced images consistent with the
+    behavior of the sequential reader and consistent with the manual, by
+    moving some code out of the PNG_READ_INTERLACING_SUPPORTED blocks. The
+    row_callback now receives the proper pass number and unexpanded rows, when
+    png_combine_row() isn't built or used, and png_set_interlace_handling()
+    is not called.
+  Allow PNG_sRGB_PROFILE_CHECKING = (-1) to mean no sRGB profile checking.
+
+Version 1.6.11beta05 [April 26, 2014]
+  Do not reject ICC V2 profiles that lack padding (Kai-Uwe Behrmann).
+  Relocated closing bracket of the sRGB profile test loop to avoid getting
+    "Not recognizing known sRGB profile that has been edited" warning for
+    ICC V2 profiles that lack the MD5 signature in the profile header.
+
+Version 1.6.11beta06 [May 19, 2014]
+  Added PNG_SKIP_sRGB_CHECK_PROFILE choice for png_set_option().
+
+Version 1.6.11rc01 [May 27, 2014]
+  No changes.
+
+Version 1.6.11rc02 [June 3, 2014]
+  Test ZLIB_VERNUM instead of PNG_ZLIB_VERNUM in contrib/tools/pngfix.c
+
+Version 1.6.11 [June 5, 2014]
+  No changes.
+
+Version 1.6.12rc01 [June 6, 2014]
+  Relocated new code from 1.6.11beta06 in png.c to a point after the
+    declarations (Max Stepin).
+
+Version 1.6.12rc02 [June 7, 2014]
+  Changed file permissions of contrib/tools/intgamma.sh,
+    test-driver, and compile from 0644 to 0755 (Cosmin).
+
+Version 1.6.12rc03 [June 8, 2014]
+  Ensure "__has_attribute()" macro exists before trying to use it with
+    old clang compilers (MacPorts Ticket #43939).
+
+Version 1.6.12 [June 12, 2014]
+  No changes.
+
+Version 1.6.13beta01 [July 4, 2014]
+  Quieted -Wsign-compare and -Wclobber compiler warnings in
+    contrib/pngminus/*.c
+  Added "(void) png_ptr;" where needed in contrib/gregbook to quiet
+    compiler complaints about unused pointers.
+  Split a long output string in contrib/gregbook/rpng2-x.c.
+  Added "PNG_SET_OPTION" requirement for sRGB chunk support to pnglibconf.dfa,
+    Needed for write-only support (John Bowler).
+  Changed "if defined(__ARM_NEON__)" to
+    "if (defined(__ARM_NEON__) || defined(__ARM_NEON))" (James Wu).
+  Fixed clang no-warning builds: png_digit was defined but never used.
+    
+Version 1.6.13beta02 [July 21, 2014]
+  Fixed an incorrect separator ("/" should be "\") in scripts/makefile.vcwin32
+    (bug report from Wolfgang S. Kechel).  Bug was introduced in libpng-1.6.11.
+    Also fixed makefile.bc32, makefile.bor, makefile.msc, makefile.intel, and
+    makefile.tc3 similarly.
+
+Version 1.6.13beta03 [August 3, 2014]
  Removed scripts/makefile.elf. It has not worked since libpng-1.5.0beta14
    due to elimination of the PNG_FUNCTION_EXPORT and PNG_DATA_EXPORT
    definitions from pngconf.h.
  Ensure that CMakeLists.txt makes the target "lib" directory before making
    symbolic link into it (SourceForge bug report #226 by Rolf Timmermans).
-  Added opinion that the ECCN (Export Control Classification Number) for
-    libpng is EAR99 to the README file.

-Version 1.7.0beta36 [September 27, 2014]
-  Updated scripts/makefiles from libpng-1.6.13beta04.
-  Minor updates to the manual from libpng-1.6.14beta04.
-  Fixed incorrect handling of the iTXt compression flag in pngrutil.c
-    (bug report by Shunsaku Hirata).  Bug was introduced in libpng-1.6.0.
-
-Version 1.7.0beta37 [September 28, 2014]
-  Merged scripts/*, pngvalid.c and pngfix.c with libpng-1.6.14beta04.
-
-Version 1.7.0beta38 [October 17, 2014]
-  Added "option READ_iCCP enables READ_COMPRESSED_TEXT" to pnglibconf.dfa
-  Removed unused "text_len" parameter from private function png_write_zTXt().
-  Conditionally compile some code in png_deflate_claim(), when
-    PNG_WARNINGS_SUPPORTED and PNG_ERROR_TEXT_SUPPORTED are disabled.
-  Replaced repeated code in pngpread.c with PNG_PUSH_SAVE_BUFFER_IF_FULL.
-  Added "chunk iTXt enables TEXT" and "chunk zTXt enables TEXT"
-    to pnglibconf.dfa.
-  Removed "option READ_COMPRESSED_TEXT enables READ_TEXT" from pnglibconf.dfa,
-    to make it possible to configure a libpng that supports iCCP but not TEXT.
-  Removed "option WRITE_COMPRESSED_TEXT enables WRITE_TEXT" from pnglibconf.dfa
-  Only mark text chunks as written after successfully writing them.
-
-Version 1.7.0beta39 [November 1, 2014]
-  Ported cosmetic changes from libpng-1.6.15beta02.
-
-Version 1.7.0beta40 [November 6, 2014]
-  Made a one-line revision to configure.ac to support ARM on aarch64
-    (bug report by Marcin Juszkiewicz, fix by John Bowler).
-  Use png_get_libpng_ver(NULL) instead of PNG_LIBPNG_VER_STRING in
-    example.c, pngtest.c, and applications in the contrib directory.
-  Avoid out-of-bounds memory access in png_user_version_check().
-  Simplified and future-proofed png_user_version_check().
-  Fixed GCC unsigned int->float warnings. Various versions of GCC
-    seem to generate warnings when an unsigned value is implicitly
-    converted to double. This is probably a GCC bug but this change
-    avoids the issue by explicitly converting to (int) where safe.
-  Free all allocated memory in pngimage. The file buffer cache was left
-    allocated at the end of the program, harmless but it causes memory
-    leak reports from clang.
-  Fixed array size calculations to avoid warnings. At various points
-    in the code the number of elements in an array is calculated using
-    sizeof.  This generates a compile time constant of type (size_t) which
-    is then typically assigned to an (unsigned int) or (int). Some versions
-    of GCC on 64-bit systems warn about the apparent narrowing, even though
-    the same compiler does apparently generate the correct, in-range,
-    numeric constant.  This adds appropriate, safe, casts to make the
-    warnings go away.
-
-Version 1.7.0beta41 [November 7, 2014]
-  Added #ifdef PNG_16BIT_SUPPORTED/#endif around png_log16bit() and
-    png_do_swap().
-  Changed all "#endif /* PNG_FEATURE_SUPPORTED */" to "#endif /* FEATURE */"
-
-Version 1.7.0beta42 [November 20, 2014]
-  The macros passed in the command line to Borland make were ignored if
-    similarly-named macros were already defined in makefiles. This behavior
-    is different from POSIX make and other make programs.  Surround the
-    macro definitions with ifndef guards (Cosmin).
-  Added "-D_CRT_SECURE_NO_WARNINGS" to CFLAGS in scripts/makefile.vcwin32.
-  Removed the obsolete $ARCH variable from scripts/makefile.darwin.
-  Merged clang no-warning fix from libpng-1.6.13: png_digit was defined
-    but never used in pngerror.c.
-
-Version 1.7.0beta43 [December 18, 2014]
-  Added ".align 2" to arm/filter_neon.S to support old GAS assemblers that
-    don't do alignment correctly.
-  Revised Makefile.am and scripts/*.dfn to work with MinGW/MSYS;
-    renamed scripts/*.dfn to scripts/*.c (Bob Friesenhahn and John Bowler).
-  Quiet a "comparison always true" warning in pngstest.c (John Bowler).
-
-Version 1.7.0beta44 [December 23, 2014]
-  Restored a test on width that was removed from png.c at libpng-1.6.9
-    (Bug report by Alex Eubanks, CVE-2015-0973).
-  Fixed an overflow in png_combine_row() with very wide interlaced images
-    (Bug report and fix by John Bowler, CVE-2014-9475).
-  Corrected the width limit calculation in png_check_IHDR().
-  Removed extraneous handling of PNG_SAFE_LIMITS_SUPPORTED from pngconf.h
-
-Version 1.7.0beta45 [December 28, 2014]
-  Eliminated the PNG_SAFE_LIMITS macro and restored the 1-million-column
-    and 1-million-row default limits in pnglibconf.dfa, that can be reset
-    by the user at build time or run time.  This provides a more robust
-    defense against DOS and as-yet undiscovered overflows.
-  Removed user limits from pngfix. Also pass NULL pointers to
-    png_read_row to skip the unnecessary row de-interlace stuff.
-  Added testing of png_set_packing() to pngvalid.c
-
-Version 1.7.0beta46 [January 2, 2015]
-  Regenerated configure scripts in the tar distributions with libtool-2.4.4
-  Implement previously untested cases of libpng transforms in pngvalid.c
-  Fixed byte order in 2-byte filler, in png_do_read_filler().
-  Allow user to call png_get_IHDR() with NULL arguments (Reuben Hawkins).
-
-Version 1.7.0beta47 [January 29, 2015]
-  Made the check for out-of-range values in png_set_tRNS() detect
-    values that are exactly 2^bit_depth, and work on 16-bit platforms.
-  Added PNG_SKIP_sRGB_CHECK_PROFILE choice for png_set_option().
-  Report all IHDR errors before exiting png_check_IHDR().
-  Merged some parts of libpng-1.6.17beta01 and libpng-1.7.0beta47.
-  Added #ifndef __COVERITY__ where needed in png.c, pngrutil.c and
-    pngset.c to avoid warnings about dead code.
-
-Version 1.7.0beta48 [February 7, 2015]
-  Work around one more Coverity-scan dead-code warning.
-  Do not build png_product2() when it is unused.
-
-Version 1.7.0beta49 [February 11, 2015]
-  Combined sub_row, up_row, avg_row, and paeth_row buffers into a
-    single try_row buffer.
-  Added PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED macro, on by default.
-  Consolidated redundant code in pngwutil.c
-  Deal with integer overflow of sum in pngwutil.c
-
-Version 1.7.0beta50 [February 15, 2015]
-  Combined sub_row, up_row, avg_row, and paeth_row buffers into a
-    single try_row buffer and in cases where two or more of those are
-    being tested, a second tst_row buffer.  This improves CPU speed
-    over that achieved by libpng-1.7.0beta49.
-
-Version 1.7.0beta51 [February 17, 2015]
-  Combined similar parts of png_write_find_filter() into a png_increase_lmins()
-    function.
-  Display user limits in the output from pngtest.
-  Replaced test for harmless integer overflow (wraparound) in pngwutil.c
-    with a method that prevents overflow and does not increase cpu usage
-    significantly.
-
-Version 1.7.0beta52 [February 21, 2015]
-  Added information about setjmp/simplified API interaction in the
-    manual page and INSTALL file. Added information about using
-    row_pointers with a single height*width*bpp allocated block
-    to the manual page.
-  Rebuilt configure scripts with automake-1.15 and libtool-2.4.6
+Version 1.6.13beta04 [August 8, 2014]
+  Added opinion about the ECCN (Export Control Classification Number) for
+    libpng being EAR99 to README
+  Eliminated use of "$<" in makefiles, when copying $PNGLIBCONF_H_PREBUILT.
+    This does not work on some versions of make; bug introduced in libpng
+    version 1.6.11.

 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
@@ -5025,4 +4979,3 @@ to subscribe)
 or to glennrp at users.sourceforge.net

 Glenn R-P
-#endif
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -15,8 +15,8 @@ project(libpng C)
 enable_testing()

 set(PNGLIB_MAJOR 1)
-set(PNGLIB_MINOR 7)
-set(PNGLIB_RELEASE 0)
+set(PNGLIB_MINOR 6)
+set(PNGLIB_RELEASE 13)
 set(PNGLIB_NAME libpng${PNGLIB_MAJOR}${PNGLIB_MINOR})
 set(PNGLIB_VERSION ${PNGLIB_MAJOR}.${PNGLIB_MINOR}.${PNGLIB_RELEASE})

@@ -253,9 +253,9 @@ endif(NOT WIN32 OR CYGWIN OR MINGW)
 # SET UP LINKS
 if(PNG_SHARED)
  set_target_properties(${PNG_LIB_NAME} PROPERTIES
-#   VERSION 17.${PNGLIB_RELEASE}.1.7.0beta52
-    VERSION 17.${PNGLIB_RELEASE}.0
-    SOVERSION 17
+#   VERSION 16.${PNGLIB_RELEASE}.1.6.13beta04
+    VERSION 16.${PNGLIB_RELEASE}.0
+    SOVERSION 16
    CLEAN_DIRECT_OUTPUT 1)
 endif()
 if(PNG_STATIC)
@@ -287,7 +287,7 @@ if(NOT SKIP_INSTALL_LIBRARIES AND NOT SKIP_INSTALL_ALL )
      ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR})

  if(PNG_SHARED)
-    # Create a symlink for libpng.dll.a => libpng17.dll.a on Cygwin
+    # Create a symlink for libpng.dll.a => libpng16.dll.a on Cygwin
    if(CYGWIN OR MINGW)
       get_target_property(BUILD_TARGET_LOCATION ${PNG_LIB_NAME} LOCATION_${CMAKE_BUILD_TYPE})
       CREATE_SYMLINK(${BUILD_TARGET_LOCATION} libpng${CMAKE_IMPORT_LIBRARY_SUFFIX})
--- a/59
+++ b/59
@@ -17,8 +17,8 @@ VIII. Configuring libpng for 16-bit platforms
 XII. Configuring for compiler xxx:
 XIII. Removing unwanted object code
 XIV. Changes to the build and configuration of libpng in libpng-1.5.x
-  XV. Setjmp/longjmp issues
- XVI. Other sources of information about libpng
+  XV. Configuring libpng for multiprocessing
+ XVI. Other sources of information about libpng:

 I. Simple installation

@@ -32,15 +32,6 @@ and ignore the rest of this document.  "/path" is the path to the directory
 where you want to install the libpng "lib", "include", and "bin"
 subdirectories.

-If you downloaded a GIT clone, you will need to run ./autogen.sh before
-running ./configure, to create "configure" and "Makefile.in" which are
-not included in the GIT repository.
-
-Note that "configure" is only included in the "*.tar" distributions and not
-in the "*.zip" or "*.7z" distributions. If you downloaded one of those
-distributions, see "Building with project files" or "Building with makefiles",
-below.
-
 II. Rebuilding the configure scripts

 If configure does not work on your system, or if you have a need to
@@ -120,7 +111,8 @@ Your directory structure should look like this:
      libpng  (this directory)
          INSTALL (this file)
          README
-          *.h, *.c  => libpng source files
+          *.h
+          *.c
          CMakeLists.txt    =>  "cmake" script
          configuration files:
             configure.ac, configure, Makefile.am, Makefile.in,
@@ -128,10 +120,15 @@ Your directory structure should look like this:
             libpng-config.in, aclocal.m4, config.h.in, config.sub,
             depcomp, install-sh, mkinstalldirs, test-pngtest.sh
          contrib
-             arm-neon, conftest, examples, gregbook, libtests, pngminim,
-             pngminus, pngsuite, tools, visupng
+             gregbook
+             libtests
+             pngminim
+             pngminus
+             pngsuite
+             visupng
          projects
-             cbuilder5, owatcom, visualc71, vstudio, xcode
+             visualc71
+             vstudio
          scripts
             makefile.*
             *.def (module definition files)
@@ -139,7 +136,11 @@ Your directory structure should look like this:
          pngtest.png
          etc.
      zlib
-          README, *.h, *.c contrib, etc.
+          README
+          *.h
+          *.c
+          contrib
+          etc.

 If the line endings in the files look funny, you may wish to get the other
 distribution of libpng.  It is available in both tar.gz (UNIX style line
@@ -148,7 +149,7 @@ endings) and zip (DOS style line endings) formats.
 VI. Building with project files

 If you are building libpng with MSVC, you can enter the
-libpng projects\visualc71 or vstudio directory and follow the instructions
+libpng projects\visualc6 or visualc71 directory and follow the instructions
 in README.txt.

 Otherwise enter the zlib directory and follow the instructions in zlib/README,
@@ -332,7 +333,7 @@ built.  pngconf.h no longer includes pngusr.h; therefore, pngusr.h is ignored
 after the build of pnglibconf.h and it is never included in an application
 build.

-The formerly used alternative of adding a list of feature macros to the
+The rarely used alternative of adding a list of feature macros to the
 CPPFLAGS setting in the build also still works; however, the macros will be
 copied to pnglibconf.h and this may produce macro redefinition warnings
 when the individual C files are compiled.
@@ -348,21 +349,14 @@ functioning awk called 'nawk'.

 Configuration options are now documented in scripts/pnglibconf.dfa.  This
 file also includes dependency information that ensures a configuration is
-consistent; that is, if a feature is switched off, dependent features are
-also switched off.  As a recommended alternative to using feature macros in
+consistent; that is, if a feature is switched off dependent features are
+also removed.  As a recommended alternative to using feature macros in
 pngusr.h a system builder may also define equivalent options in pngusr.dfa
 (or, indeed, any file) and add that to the configuration by setting
 DFA_XTRA to the file name.  The makefiles in contrib/pngminim illustrate
-how to do this, and also illustrate a case where pngusr.h is still required.
+how to do this, and illustrate a case where pngusr.h is still required.

-After you have built libpng, the definitions that were recorded in
-pnglibconf.h are available to your application (pnglibconf.h is included
-in png.h and gets installed alongside png.h and pngconf.h in your
-$PREFIX/include directory).  Do not edit pnglibconf.h after you have built
-libpng, because than the settings would not accurately reflect the settings
-that were used to build libpng.
-
-XV. Setjmp/longjmp issues
+XV. Configuring libpng for multiprocessing

 Libpng uses setjmp()/longjmp() for error handling.  Unfortunately setjmp()
 is known to be not thread-safe on some platforms and we don't know of
@@ -375,11 +369,6 @@ configure libpng with PNG_NO_SETJMP in your pngusr.dfa file, with

 in your pnglibconf.h or pngusr.h.

-Starting with libpng-1.6.0, the library included a "simplified API".
-This requires setjmp/longjmp, so you must either build the library
-with PNG_SETJMP_SUPPORTED defined, or with PNG_SIMPLIFIED_READ_SUPPORTED
-and PNG_SIMPLIFIED_WRITE_SUPPORTED undefined.
-
 XVI. Other sources of information about libpng:

 Further information can be found in the README and libpng-manual.txt
@@ -399,7 +388,7 @@ CFLAGS="-Wall -O -funroll-loops \
 --with-pkgconfigdir=/usr/lib/pkgconfig --includedir=/usr/include

 You can alternatively specify --includedir=/usr/include, /usr/local/include,
-/usr/include/libpng17, or whatever.
+/usr/include/libpng%NN%, or whatever.

 If you find that the configure script is out-of-date or is not supporting
 your platform properly, try running autogen.sh to regenerate "configure",
--- a/6
+++ b/6
@@ -10,8 +10,8 @@ this sentence.

 This code is released under the libpng license.

-libpng versions 1.2.6, August 15, 2004, through 1.7.0beta52, February 21, 2015, are
-Copyright (c) 2004, 2006-2015 Glenn Randers-Pehrson, and are
+libpng versions 1.2.6, August 15, 2004, through 1.6.13beta04, August 8, 2014, are
+Copyright (c) 2004, 2006-2014 Glenn Randers-Pehrson, and are
 distributed according to the same disclaimer and license as libpng-1.2.5
 with the following individual added to the list of Contributing Authors

@@ -108,4 +108,4 @@ certification mark of the Open Source Initiative.

 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-February 21, 2015
+August 8, 2014
--- a/Makefile.am
+++ b/Makefile.am
@@ -129,7 +129,7 @@ EXTRA_DIST= \
 	$(TESTS) $(XFAIL_TESTS) tests/pngstest \
 	CMakeLists.txt example.c libpng-manual.txt

-SCRIPT_CLEANFILES=scripts/*.out scripts/*.chk scripts/pnglibconf.c
+SCRIPT_CLEANFILES=scripts/*.out scripts/*.chk scripts/pnglibconf.dfn

 CLEANFILES= *.tf? pngout.png libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.pc \
 	libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config libpng.vers libpng.sym \
@@ -145,14 +145,14 @@ config.sub configure depcomp install-sh ltmain.sh missing
 PNG_COPTS = @PNG_COPTS@
 AM_CFLAGS = ${PNG_COPTS}

-# DFNCPP is normally just "CPP -E" - the C preprocessor - but on Solaris and
-# maybe other operating systems (NeXT?) the C preprocessor selected by configure
+# DFNCPP is normally just CPP - the C preprocessor - but on Solaris and maybe
+# other operating systems (NeXT?) the C preprocessor selected by configure
 # checks input tokens for validity - effectively it performs part of the ANSI-C
 # parsing - and therefore fails with the .df files.  configure.ac has special
 # checks for this and sets DFNCPP appropriately.
 DFNCPP = @DFNCPP@

-SUFFIXES = .chk .out
+SUFFIXES = .chk .dfn .out

 $(PNGLIB_BASENAME).pc: libpng.pc
 	cp libpng.pc $@
@@ -165,8 +165,6 @@ scripts/prefix.out: png.h pngconf.h pnglibconf.out
 scripts/symbols.out: png.h pngconf.h $(srcdir)/scripts/pnglibconf.h.prebuilt
 scripts/intprefix.out: pnglibconf.h

-pnglibconf.out: config.h
-
 libpng.sym: scripts/sym.out
 	rm -f $@
 	cp $? $@
@@ -178,7 +176,7 @@ if DO_PNG_PREFIX
 # Rename functions in scripts/prefix.out with a PNG_PREFIX prefix.
 # Rename macros in scripts/macro.lst from PNG_PREFIXpng_ to PNG_ (the actual
 # implementation of the macro).
-pnglibconf.h: pnglibconf.out scripts/prefix.out scripts/macro.lst config.h
+pnglibconf.h: pnglibconf.out scripts/prefix.out scripts/macro.lst
 	rm -f $@
 	$(AWK) 's==0 && NR>1{print prev}\
 	   s==0{prev=$$0}\
@@ -239,17 +237,18 @@ if DO_PNG_PREFIX
 SYMBOL_CFLAGS += -DPNG_PREFIX='@PNG_PREFIX@'
 endif

-.c.out:
-	rm -f $@ $*.tf[12]
+.dfn.out:
+	rm -f $@ $*.c $*.tf[12]
 	test -d scripts || mkdir scripts || test -d scripts
+	echo '#include "$<"' >$*.c
 	$(DFNCPP) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES)\
-	    $(CPPFLAGS) $(SYMBOL_CFLAGS) $< > $*.tf1
+	    $(CPPFLAGS) $(SYMBOL_CFLAGS) $*.c > $*.tf1
 	$(AWK) -f "${srcdir}/scripts/dfn.awk" out="$*.tf2" $*.tf1 1>&2
-	rm -f $*.tf1
+	rm -f $*.c $*.tf1
 	mv $*.tf2 $@

-# The .c file for pnglibconf.h is machine generated
-pnglibconf.c: scripts/pnglibconf.dfa scripts/options.awk pngconf.h pngusr.dfa $(DFA_XTRA)
+# The .dfn file for pnglibconf.h is machine generated
+pnglibconf.dfn: scripts/pnglibconf.dfa scripts/options.awk pngconf.h pngusr.dfa $(DFA_XTRA)
 	rm -f $@ $*.tf[45]
 	$(AWK) -f ${srcdir}/scripts/options.awk out=$*.tf4 version=search\
 	    ${srcdir}/pngconf.h ${srcdir}/scripts/pnglibconf.dfa\
@@ -269,7 +268,7 @@ scripts/symbols.chk: scripts/checksym.awk scripts/symbols.def scripts/symbols.ou

 # used on demand to regenerate the standard header, CPPFLAGS should
 # be empty - no non-standard defines
-scripts/pnglibconf.c: scripts/pnglibconf.dfa scripts/options.awk pngconf.h
+scripts/pnglibconf.dfn: scripts/pnglibconf.dfa scripts/options.awk pngconf.h
 	rm -f $@ pnglibconf.tf[67]
 	test -z "$(CPPFLAGS)"
 	echo "com @PNGLIB_VERSION@ STANDARD API DEFINITION" |\
--- a/21
+++ b/21
@@ -1,4 +1,4 @@
-README for libpng version 1.7.0beta52 - February 21, 2015 (shared library 17.0)
+README for libpng version 1.6.13beta04 - August 8, 2014 (shared library 16.0)
 See the note about version numbers near the top of png.h

 See INSTALL for instructions on how to install libpng.
@@ -23,25 +23,18 @@ earlier versions if you are using a shared library.  The type of the
 png_uint_32, which will affect shared-library applications that use
 this function.

-To avoid problems with changes to the internals of png info_struct,
+To avoid problems with changes to the internals of png_info_struct,
 new APIs have been made available in 0.95 to avoid direct application
 access to info_ptr.  These functions are the png_set_<chunk> and
 png_get_<chunk> functions.  These functions should be used when
 accessing/storing the info_struct data, rather than manipulating it
 directly, to avoid such problems in the future.

-It is important to note that the APIs did not make current programs
+It is important to note that the APIs do not make current programs
 that access the info struct directly incompatible with the new
-library, through libpng-1.2.x.  In libpng-1.4.x, which was meant to
-be a transitional release, members of the png_struct and the
-info_struct can still be accessed, but the compiler will issue a
-warning about deprecated usage.  Since libpng-1.5.0, direct access
-to these structs is not allowed, and the definitions of the structs
-reside in private pngstruct.h and pnginfo.h header files that are not
-accessible to applications.  It is strongly suggested that new
-programs use the new APIs (as shown in example.c and pngtest.c), and
-older programs be converted to the new format, to facilitate upgrades
-in the future.
+library.  However, it is strongly suggested that new programs use
+the new APIs (as shown in example.c and pngtest.c), and older programs
+be converted to the new format, to facilitate upgrades in the future.
 ****

 Additions since 0.90 include the ability to compile libpng as a
@@ -190,7 +183,7 @@ Files in this distribution:
       pngminus         =>  Simple pnm2png and png2pnm programs
       pngsuite         =>  Test images
       tools            =>  Various tools
-       visupng          =>  Contains a MSVC workspace for VisualPng
+       visupng      =>  Contains a MSVC workspace for VisualPng
      projects      =>  Contains project files and workspaces for
                        building a DLL
       owatcom          =>  Contains a WATCOM project for building libpng
--- a/arm/arm_init.c
+++ b/arm/arm_init.c
@@ -3,7 +3,7 @@
 *
 * Copyright (c) 2014 Glenn Randers-Pehrson
 * Written by Mans Rullgard, 2011.
- * Last changed in libpng 1.6.16 [December 22, 2014]
+ * Last changed in libpng 1.6.10 [(PENDING RELEASE)]
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
@@ -17,7 +17,6 @@
 #include "../pngpriv.h"

 #ifdef PNG_READ_SUPPORTED
-
 #if PNG_ARM_NEON_OPT > 0
 #ifdef PNG_ARM_NEON_CHECK_SUPPORTED /* Do run-time checks */
 /* WARNING: it is strongly recommended that you do not build libpng with
@@ -131,4 +130,4 @@ png_init_filter_functions_neon(png_structp pp, unsigned int bpp)
   }
 }
 #endif /* PNG_ARM_NEON_OPT > 0 */
-#endif /* READ */
+#endif /* PNG_READ_SUPPORTED */
--- a/arm/filter_neon.S
+++ b/arm/filter_neon.S
@@ -1,17 +1,18 @@

 /* filter_neon.S - NEON optimised filter functions
 *
- * Copyright (c) 2014 Glenn Randers-Pehrson
+ * Copyright (c) 2013 Glenn Randers-Pehrson
 * Written by Mans Rullgard, 2011.
- * Last changed in libpng 1.6.16 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.8 [December 19, 2013]
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
 * and license in png.h
 */

-/* This is required to get the symbol renames, which are #defines, and the
- * definitions (or not) of PNG_ARM_NEON_OPT and PNG_ARM_NEON_IMPLEMENTATION.
+/* This is required to get the symbol renames, which are #defines, and also
+ * includes the definition (or not) of PNG_ARM_NEON_OPT and
+ * PNG_ARM_NEON_IMPLEMENTATION.
 */
 #define PNG_VERSION_INFO_ONLY
 #include "../pngpriv.h"
@@ -20,8 +21,6 @@
 .section .note.GNU-stack,"",%progbits /* mark stack as non-executable */
 #endif

-#ifdef PNG_READ_SUPPORTED
-
 /* Assembler NEON support - only works for 32-bit ARM (i.e. it does not work for
 * ARM64).  The code in arm/filter_neon_intrinsics.c supports ARM64, however it
 * only works if -mfpu=neon is specified on the GCC command line.  See pngpriv.h
@@ -29,6 +28,7 @@
 */
 #if PNG_ARM_NEON_IMPLEMENTATION == 2 /* hand-coded assembler */

+#ifdef PNG_READ_SUPPORTED
 #if PNG_ARM_NEON_OPT > 0

 #ifdef __ELF__
@@ -47,13 +47,6 @@ ELF     .size   \name, . - \name
        .purgem endfunc
    .endm
        .text
-
-        /* Explicitly specifying alignment here because some versions of
-         * GAS don't align code correctly.  This is harmless in correctly
-         * written versions of GAS.
-         */
-        .align 2
-
    .if \export
        .global \name
    .endif
@@ -249,5 +242,5 @@ func    png_read_filter_row_paeth3_neon, export=1
        pop             {r4,pc}
 endfunc
 #endif /* PNG_ARM_NEON_OPT > 0 */
+#endif /* PNG_READ_SUPPORTED */
 #endif /* PNG_ARM_NEON_IMPLEMENTATION == 2 (assembler) */
-#endif /* READ */
--- a/arm/filter_neon_intrinsics.c
+++ b/arm/filter_neon_intrinsics.c
@@ -1,11 +1,11 @@

 /* filter_neon_intrinsics.c - NEON optimised filter functions
 *
- * Copyright (c) 2014 Glenn Randers-Pehrson
+ * Copyright (c) 2013 Glenn Randers-Pehrson
 * Written by James Yu <james.yu at linaro.org>, October 2013.
 * Based on filter_neon.S, written by Mans Rullgard, 2011.
 *
- * Last changed in libpng 1.6.16 [December 22, 2014]
+ * Last changed in libpng 1.6.8 [December 19, 2013]
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
@@ -14,8 +14,6 @@

 #include "../pngpriv.h"

-#ifdef PNG_READ_SUPPORTED
-
 /* This code requires -mfpu=neon on the command line: */
 #if PNG_ARM_NEON_IMPLEMENTATION == 1 /* intrinsics code from pngpriv.h */

@@ -37,6 +35,7 @@
 #define png_ldr(type,pointer)\
   (temp_pointer = png_ptr(type,pointer), *temp_pointer)

+#ifdef PNG_READ_SUPPORTED
 #if PNG_ARM_NEON_OPT > 0

 void
@@ -369,5 +368,5 @@ png_read_filter_row_paeth4_neon(png_row_infop row_info, png_bytep row,
 }

 #endif /* PNG_ARM_NEON_OPT > 0 */
+#endif /* PNG_READ_SUPPORTED */
 #endif /* PNG_ARM_NEON_IMPLEMENTATION == 1 (intrinsics) */
-#endif /* READ */
--- a/configure.ac
+++ b/configure.ac
@@ -18,7 +18,7 @@ AC_PREREQ([2.68])

 dnl Version number stuff here:

-AC_INIT([libpng],[1.7.0beta52],[png-mng-implement@lists.sourceforge.net])
+AC_INIT([libpng],[1.6.13beta04],[png-mng-implement@lists.sourceforge.net])
 AC_CONFIG_MACRO_DIR([scripts])

 # libpng does not follow GNU file name conventions (hence 'foreign')
@@ -39,10 +39,10 @@ dnl automake, so the following is not necessary (and is not defined anyway):
 dnl AM_PREREQ([1.11.2])
 dnl stop configure from automagically running automake

-PNGLIB_VERSION=1.7.0beta52
+PNGLIB_VERSION=1.6.13beta04
 PNGLIB_MAJOR=1
-PNGLIB_MINOR=7
-PNGLIB_RELEASE=0
+PNGLIB_MINOR=6
+PNGLIB_RELEASE=13

 dnl End of version number stuff

@@ -60,10 +60,10 @@ AC_PROG_INSTALL
 AC_PROG_LN_S
 AC_PROG_MAKE_SET

-dnl libtool/libtoolize; version 2.4.4 is the tested version, this or any
+dnl libtool/libtoolize; version 2.4.2 is the tested version, this or any
 dnl compatible later version may be used
 LT_INIT([win32-dll])
-LT_PREREQ([2.4.4])
+LT_PREREQ([2.4.2])

 # Some awks crash when confronted with pnglibconf.dfa, do a test run now
 # to make sure this doesn't happen
@@ -79,7 +79,7 @@ fi

 # This is a remnant of the old cc -E validation, where it may have been
 # necessary to use a different preprocessor for .dfn files
-DFNCPP="$CPP -E"
+DFNCPP="$CPP"
 AC_SUBST(DFNCPP)

 # -Werror cannot be passed to GCC in CFLAGS because configure will fail (it
@@ -109,146 +109,30 @@ AC_ARG_ENABLE(werror,

 # Checks for header files.
 AC_HEADER_STDC
-# Headers used in pngpriv.h:
-AC_CHECK_HEADERS([assert.h stdlib.h string.h float.h fp.h math.h m68881.h])
-# Additional headers used in pngconf.h:
-AC_CHECK_HEADERS([limits.h stddef.h stdio.h setjmp.h time.h])
-# Used by pngread.c (for the simplified API):
-AC_CHECK_HEADERS([errno.h])
-# The following are not required for the standard 'make' build of libpng:
-# Additional requirements of contrib/libtests/makepng.c:
-AC_CHECK_HEADERS([ctype.h])
-# Additional requirements of contrib/libtests/pngvalid.c:
-AC_CHECK_HEADERS([fenv.h])

 # Checks for typedefs, structures, and compiler characteristics.
-# Most of these have been removed from 1.7.0 because they checked for non-ANSI-C
-# behaviors and the result were, anyway, not used by earlier versions of libpng.
+AC_C_CONST
+AC_TYPE_SIZE_T
+AC_STRUCT_TM
 AC_C_RESTRICT

-# Checks for library functions; these need to be in order, least demanding to
-# most because the -l directives are added to the head of the list at each
-# check.
-# ANSI-C functions: all are required but they don't have to be implemented in
-# libc, it is perfectly ok to configure with an extra, wrapper, library preset
-# in LIBS.  NOTE: this list may not be complete
-AC_CHECK_FUNCS([memset memcpy strncpy],,
-               AC_MSG_FAILURE([missing ANSI-C functions]))
-
-# floor and ceil are required for FLOATING_POINT, but they can be turned off on
-# the configure command line (and they are independent.)  Default is to 'on'
-AC_ARG_ENABLE([floating-point],
-   AS_HELP_STRING([[[--enabled-floating-point]]],
-      [Enable floating point APIs (default: yes)]),,
-   [enable_floating_point=yes])
-
-AC_ARG_ENABLE([fixed-point],
-   AS_HELP_STRING([[[--enable-fixed-point]]],
-      [Enable fixed point APIs (default: yes)]),,
-   [enable_fixed_point=yes])
-
-AC_ARG_ENABLE([floating-arithmetic],
-   AS_HELP_STRING([[[--enable-floating-arithmetic]]],
-      [Use floating point arithmetic internally (default: yes)]),,
-   [enable_floating_arithmetic=yes])
-
-# Check for a requirement for math library support
-if test "$enable_floating_arithmetic" = yes
-then
-   AC_SEARCH_LIBS([floor],[m],,
-                  [AC_MSG_WARN([not found])
-                   enable_floating_arithmetic=no])
-   AC_SEARCH_LIBS([frexp],[m],,
-                  [AC_MSG_WARN([not found])
-                   enable_floating_arithmetic=no])
-   AC_SEARCH_LIBS([modf],[m],,
-                  [AC_MSG_WARN([not found])
-                   enable_floating_arithmetic=no])
-   AC_SEARCH_LIBS([atof],[m],,
-                  [AC_MSG_WARN([not found])
-                   enable_floating_arithmetic=no])
-   AC_SEARCH_LIBS([pow],[m],,
-                  [AC_MSG_WARN([not found])
-                   enable_floating_arithmetic=no])
-fi
-
-# Set the relevant defines if required (only if required), this will override
-# anything on the command line.
-if test "$enable_floating_point" != yes
-then
-   AC_MSG_NOTICE([Floating point APIs disabled])
-   AC_DEFINE([PNG_NO_FLOATING_POINT],[1],
-             [No support for floating point APIs])
-fi
-if test "$enable_fixed_point" != yes
-then
-   AC_MSG_NOTICE([Fixed point APIs disabled])
-   AC_DEFINE([PNG_NO_FIXED_POINT],[1],
-             [No support for fixed point APIs])
-fi
-if test "$enable_floating_arithmetic" != yes
-then
-   AC_MSG_NOTICE([Fixed point arithmetic will be used])
-   AC_DEFINE([PNG_NO_FLOATING_ARITHMETIC],[1],
-             [No support for floating point arithmetic])
-fi
+# Checks for library functions.
+AC_FUNC_STRTOD
+AC_CHECK_FUNCS([memset], , AC_MSG_ERROR(memset not found in libc))
+AC_CHECK_FUNCS([pow], , AC_CHECK_LIB(m, pow, , AC_MSG_ERROR(cannot find pow)) )
+AC_ARG_WITH(zlib-prefix,
+   AS_HELP_STRING([[[--with-zlib-prefix]]],
+      [prefix that may have been used in installed zlib]),
+      [ZPREFIX=${withval}],
+      [ZPREFIX='z_'])
+AC_CHECK_LIB(z, zlibVersion, ,
+    AC_CHECK_LIB(z, ${ZPREFIX}zlibVersion, , AC_MSG_ERROR(zlib not installed)))

 # The following is for pngvalid, to ensure it catches FP errors even on
 # platforms that don't enable FP exceptions, the function appears in the math
 # library (typically), it's not an error if it is not found.
-AC_SEARCH_LIBS([feenableexcept],[m],AC_DEFINE([HAVE_FEENABLEEXCEPT],[1],
-      [Define to 1 if the feenableexcept function is available]))
-# Required by pngvalid:
-AC_SEARCH_LIBS([ceil],[m])
-
-# zlib checks and arguments;
-#  package zlib: argument is the name of the library
-#  zlib-header: the name of the header file
-#  zlib-prefix: the prefix for library functions, if any
-AC_ARG_WITH([zlib],
-   AS_HELP_STRING([[[--with-zlib=<name>]]],
-                  [base name of the zlib implementation (e.g. 'z')]),,
-   [with_zlib='z'])
-
-z_prefix=
-AC_ARG_WITH([zlib-prefix],
-   AS_HELP_STRING([[[--with-zlib-prefix=<prefix>]]],
-                  [prefix for zlib API functions]),
-   [if test "$withval" = "" -o "$withval" = yes; then
-      with_zlib_prefix='z_'
-      AC_DEFINE([PNG_ZLIB_PREFIX],[z_],[Standard zlib prefix])
-   elif test "${withval}" != "no"; then
-      AC_DEFINE_UNQUOTED([PNG_ZLIB_PREFIX],[${withval}],
-         [User defined zlib prefix])
-   else
-      with_zlib_prefix=
-   fi
-   if test "$with_zlib_prefix" != ""; then
-      AC_DEFINE([Z_PREFIX],[1],[Tell zlib.h to prefix function names])
-      z_prefix="#define Z_PREFIX 1"
-   fi])
-
-AC_ARG_WITH([zlib-header],
-   AS_HELP_STRING([[[--with-zlib-header='<file>' or '"file"']]],
-      [C include argument to locate zlib header file, e.g. <zlib.h>, take
-       care to put single quotes round this on the command line]),
-   [AC_DEFINE_UNQUOTED([PNG_ZLIB_HEADER],[${withval}],[Zlib header file])],
-   with_zlib_header='<zlib.h>')
-
-# AC_CHECK_LIB isn't quite enough for this because we need the special header
-# file too.
-LIBS="-l${with_zlib} $LIBS"
-AC_MSG_CHECKING(
-   [[Library '${with_zlib}' and #include ${with_zlib_header} for symbol '${with_zlib_prefix}zlibVersion']])
-AC_LINK_IFELSE(
-   [AC_LANG_PROGRAM(
-      [[
-${z_prefix}
-#include ${with_zlib_header}
-      ]],
-      [[(void)${with_zlib_prefix}zlibVersion();]])],
-   AC_MSG_RESULT([ok]),
-   AC_MSG_FAILURE([not found]))
+AC_CHECK_LIB([m], [feenableexcept])
+AC_CHECK_FUNCS([feenableexcept])

 AC_MSG_CHECKING([if using Solaris linker])
 SLD=`$LD --version 2>&1 | grep Solaris`
@@ -294,7 +178,7 @@ AM_CONDITIONAL(HAVE_LD_VERSION_SCRIPT, test "$have_ld_version_script" = "yes")
 if test "$have_ld_version_script" = "yes"; then
    AC_MSG_CHECKING([for symbol prefix])
    SYMBOL_PREFIX=`echo "PREFIX=__USER_LABEL_PREFIX__" \
-                  | ${DFNCPP-${CC-gcc -E}} - 2>&1 \
+                  | ${CPP-${CC-gcc} -E} - 2>&1 \
                  | ${EGREP-grep} "^PREFIX=" \
                  | ${SED-sed} -e "s:^PREFIX=::" -e "s:__USER_LABEL_PREFIX__::"`
    AC_SUBST(SYMBOL_PREFIX)
@@ -426,14 +310,15 @@ AC_ARG_ENABLE([arm-neon],
 AM_CONDITIONAL([PNG_ARM_NEON],
   [test "$enable_arm_neon" != 'no' &&
    case "$host_cpu" in
-      arm*|aarch64*) :;;
+      arm*) :;;
      *)    test "$enable_arm_neon" != '';;
    esac])

 AC_MSG_NOTICE([[Extra options for compiler: $PNG_COPTS]])

 # Config files, substituting as above
-AC_CONFIG_FILES([Makefile libpng.pc])
-AC_CONFIG_FILES([libpng-config], [chmod +x libpng-config])
+AC_CONFIG_FILES([Makefile libpng.pc:libpng.pc.in])
+AC_CONFIG_FILES([libpng-config:libpng-config.in],
+   [chmod +x libpng-config])

 AC_OUTPUT
--- a/contrib/arm-neon/linux.c
+++ b/contrib/arm-neon/linux.c
@@ -2,7 +2,7 @@
 *
 * Copyright (c) 2014 Glenn Randers-Pehrson
 * Written by John Bowler, 2014.
- * Last changed in libpng 1.6.16 [December 22, 2014]
+ * Last changed in libpng 1.6.10 [March 6, 2014]
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
@@ -16,8 +16,8 @@
 * png_have_neon implemented for Linux by reading the widely available
 * pseudo-file /proc/cpuinfo.
 *
- * This code is strict ANSI-C and is probably moderately portable; it does
- * however use <stdio.h> and it assumes that /proc/cpuinfo is never localized.
+ * This code is strict ANSI-C and is probably moderately portable, it does
+ * however use <stdio.h> and assumes that /proc/cpuinfo is never localized.
 */
 #include <stdio.h>

@@ -152,10 +152,8 @@ png_have_neon(png_structp png_ptr)
      }
   }

-#ifdef PNG_WARNINGS_SUPPORTED
   else
      png_warning(png_ptr, "/proc/cpuinfo open failed");
-#endif

   return 0;
 }
--- a/contrib/gregbook/Makefile.sgi
+++ b/contrib/gregbook/Makefile.sgi
@@ -23,9 +23,9 @@

 # macros --------------------------------------------------------------------

-PNGINC = -I/usr/local/include/libpng17
-PNGLIB = -L/usr/local/lib -lpng17	  # dynamically linked against libpng
-#PNGLIB = /usr/local/lib/libpng17.a # statically linked against libpng
+PNGINC = -I/usr/local/include/libpng16
+PNGLIB = -L/usr/local/lib -lpng16	  # dynamically linked against libpng
+#PNGLIB = /usr/local/lib/libpng16.a # statically linked against libpng
 # or:
 #PNGINC = -I../..
 #PNGLIB = -L../.. -lpng
--- a/contrib/gregbook/Makefile.unx
+++ b/contrib/gregbook/Makefile.unx
@@ -26,14 +26,14 @@
 # macros --------------------------------------------------------------------

 #PNGDIR = /usr/local/lib
-#PNGINC = -I/usr/local/include/libpng17
-#PNGLIBd = -L$(PNGDIR) -lpng17 # dynamically linked, installed libpng
-#PNGLIBs = $(PNGDIR)/libpng17.a # statically linked, installed libpng
+#PNGINC = -I/usr/local/include/libpng16
+#PNGLIBd = -L$(PNGDIR) -lpng16 # dynamically linked, installed libpng
+#PNGLIBs = $(PNGDIR)/libpng16.a # statically linked, installed libpng
 # or:
 PNGDIR = ../..#	this one is for libpng-x.y.z/contrib/gregbook builds
 #PNGDIR = ../libpng
 PNGINC = -I$(PNGDIR)
-PNGLIBd = -Wl,-rpath,$(PNGDIR) -L$(PNGDIR) -lpng17	# dynamically linked
+PNGLIBd = -Wl,-rpath,$(PNGDIR) -L$(PNGDIR) -lpng16	# dynamically linked
 PNGLIBs = $(PNGDIR)/libpng.a		# statically linked, local libpng

 ZDIR = /usr/local/lib
@@ -59,15 +59,16 @@ INCS = $(PNGINC) $(ZINC) $(XINC)
 RLIBSd = $(PNGLIBd) $(ZLIBd) $(XLIB) -lm
 RLIBSs = $(PNGLIBs) $(ZLIBs) $(XLIB) -lm
 WLIBSd = $(PNGLIBd) $(ZLIBd) -lm
-WLIBSs = $(PNGLIBs) $(ZLIBs)
+WLIBSs = $(PNGLIBs) $(ZLIBs) -lm

 CC = gcc
 LD = gcc
 RM = rm -f
 CPPFLAGS = $(INCS) -DFEATURE_LOOP
 CFLAGS = -O -Wall
+#CFLAGS = -O -W -Wall -Wextra -pedantic -ansi
 # [note that -Wall is a gcc-specific compilation flag ("most warnings on")]
-# [-ansi, -pedantic and -W can also be used]
+# [-ansi, -pedantic, -Wextra, and -W can also be used]
 LDFLAGS =
 O = .o
 E =
--- a/contrib/gregbook/rpng-x.c
+++ b/contrib/gregbook/rpng-x.c
@@ -26,6 +26,8 @@
    - 1.14:  added support for X resources (thanks to Gerhard Niklasch)
    - 2.00:  dual-licensed (added GNU GPL)
    - 2.01:  fixed improper display of usage screen on PNG error(s)
+    - 2.02:  Added "void(argc);" statement to quiet pedantic compiler warnings
+             about unused variable (GR-P)

  ---------------------------------------------------------------------------

@@ -80,7 +82,7 @@

 #define PROGNAME  "rpng-x"
 #define LONGNAME  "Simple PNG Viewer for X"
-#define VERSION   "2.01 of 16 March 2008"
+#define VERSION   "2.02 of 15 June 2014"
 #define RESNAME   "rpng"        /* our X resource application name */
 #define RESCLASS  "Rpng"        /* our X resource class name */

@@ -279,15 +281,17 @@ int main(int argc, char **argv)
          "Usage:  %s [-display xdpy] [-gamma exp] [-bgcolor bg] file.png\n"
          "    xdpy\tname of the target X display (e.g., ``hostname:0'')\n"
          "    exp \ttransfer-function exponent (``gamma'') of the display\n"
-          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n"
+          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n",
+          PROGNAME, default_display_exponent);
+
+        fprintf(stderr, "\n"
          "\t\t  to the product of the lookup-table exponent (varies)\n"
          "\t\t  and the CRT exponent (usually 2.2); must be positive\n"
          "    bg  \tdesired background color in 7-character hex RGB format\n"
          "\t\t  (e.g., ``#ff7700'' for orange:  same as HTML colors);\n"
          "\t\t  used with transparent images\n"
          "\nPress Q, Esc or mouse button 1 (within image window, after image\n"
-          "is displayed) to quit.\n"
-          "\n", PROGNAME, default_display_exponent);
+          "is displayed) to quit.\n");
        exit(1);
    }

@@ -419,6 +423,8 @@ int main(int argc, char **argv)

    rpng_x_cleanup();

+    (void)argc; /* Unused */
+
    return 0;
 }

--- a/contrib/gregbook/rpng2-win.c
+++ b/contrib/gregbook/rpng2-win.c
@@ -33,6 +33,8 @@
    - 2.02:  fixed improper display of usage screen on PNG error(s); fixed
              unexpected-EOF and file-read-error cases
    - 2.03:  removed runtime MMX-enabling/disabling and obsolete -mmx* options
+    - 2.04:  
+             (GR-P)

  ---------------------------------------------------------------------------

--- a/contrib/gregbook/rpng2-x.c
+++ b/contrib/gregbook/rpng2-x.c
@@ -41,7 +41,11 @@
              unexpected-EOF and file-read-error cases; fixed Trace() cut-and-
              paste bugs
    - 2.03:  deleted runtime MMX-enabling/disabling and obsolete -mmx* options
+    - 2.04:  Added "void(foo);" statements to quiet pedantic compiler warnings
+             about unused variables (GR-P)

+  TO DO:
+             use nanosleep() instead of usleep(), which is obsolete/deprecated.
  ---------------------------------------------------------------------------

      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
@@ -95,10 +99,13 @@

 #define PROGNAME  "rpng2-x"
 #define LONGNAME  "Progressive PNG Viewer for X"
-#define VERSION   "2.03 of 25 February 2010"
+#define VERSION   "2.04 of 15 June 2014"
 #define RESNAME   "rpng2"       /* our X resource application name */
 #define RESCLASS  "Rpng"       /* our X resource class name */

+/* This is temporary until the code is rewritten to use nanosleep(). */
+#define usleep(x) sleep(((x)+499999)/1000000)
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <ctype.h>
@@ -456,40 +463,47 @@ int main(int argc, char **argv)
        fprintf(stderr, "\n%s %s:  %s\n\n", PROGNAME, VERSION, appname);
        readpng2_version_info();
        fprintf(stderr, "\n"
-          "Usage:  %s [-display xdpy] [-gamma exp] [-bgcolor bg | -bgpat pat]\n"
+          "Usage:   ");
+        fprintf(stderr,
+          "%s [-display xdpy] [-gamma exp] [-bgcolor bg | -bgpat pat]\n"
+          "        %*s [-usleep dur | -timing] [-pause]\n",
+          PROGNAME, (int)strlen(PROGNAME), " ");
+        fprintf(stderr,
 #ifdef FEATURE_LOOP
-          "        %*s [-usleep dur | -timing] [-pause] [-loop [sec]] file.png\n\n"
-#else
-          "        %*s [-usleep dur | -timing] [-pause] file.png\n\n"
+          "        [-loop [sec]]"
 #endif
+          " file.png\n\n");
+        fprintf(stderr,
          "    xdpy\tname of the target X display (e.g., ``hostname:0'')\n"
          "    exp \ttransfer-function exponent (``gamma'') of the display\n"
          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n"
-          "\t\t  to the product of the lookup-table exponent (varies)\n"
+          "\t\t  to the product of the lookup-table exponent (varies)\n",
+          default_display_exponent);
+        fprintf(stderr,
          "\t\t  and the CRT exponent (usually 2.2); must be positive\n"
          "    bg  \tdesired background color in 7-character hex RGB format\n"
          "\t\t  (e.g., ``#ff7700'' for orange:  same as HTML colors);\n"
          "\t\t  used with transparent images; overrides -bgpat\n"
          "    pat \tdesired background pattern number (0-%d); used with\n"
-          "\t\t  transparent images; overrides -bgcolor\n"
+          "\t\t  transparent images; overrides -bgcolor\n",
+          num_bgpat-1);
 #ifdef FEATURE_LOOP
+        fprintf(stderr, 
          "    -loop\tloops through background images after initial display\n"
          "\t\t  is complete (depends on -bgpat)\n"
-          "    sec \tseconds to display each background image (default = 2)\n"
+          "    sec \tseconds to display each background image (default = 2)\n");
 #endif
+        fprintf(stderr, 
          "    dur \tduration in microseconds to wait after displaying each\n"
          "\t\t  row (for demo purposes)\n"
          "    -timing\tenables delay for every block read, to simulate modem\n"
          "\t\t  download of image (~36 Kbps)\n"
          "    -pause\tpauses after displaying each pass until mouse clicked\n"
          "\nPress Q, Esc or mouse button 1 (within image window, after image\n"
-          "is displayed) to quit.\n"
-          "\n", PROGNAME,
-          (int)strlen(PROGNAME), " ", default_display_exponent, num_bgpat-1);
+          "is displayed) to quit.\n");
        exit(1);
    }

-
    if (!(infile = fopen(filename, "rb"))) {
        fprintf(stderr, PROGNAME ":  can't open PNG file [%s]\n", filename);
        ++error;
@@ -735,6 +749,8 @@ int main(int argc, char **argv)
    Trace((stderr, "about to call rpng2_x_cleanup()\n"))
    rpng2_x_cleanup();

+    (void)argc; /* Unused */
+
    return 0;
 }

@@ -1826,6 +1842,9 @@ static void rpng2_x_redisplay_image(ulg startcol, ulg startrow,
        XFlush(display);
    }

+    (void)startcol;
+    (void)width;
+
 } /* end function rpng2_x_redisplay_image() */


--- a/contrib/libtests/pngimage.c
+++ b/contrib/libtests/pngimage.c
@@ -337,9 +337,6 @@ validate_T(void)
 *    In both cases the file data is held in a linked list of buffers - not all
 *    of these are in use at any time.
 */
-#define NEW(type) ((type *)malloc(sizeof (type)))
-#define DELETE(ptr) (free(ptr))
-
 struct buffer_list
 {
   struct buffer_list *next;         /* next buffer in list */
@@ -364,25 +361,6 @@ buffer_init(struct buffer *buffer)
   buffer->current = NULL;
 }

-static void
-buffer_destroy_list(struct buffer_list *list)
-{
-   if (list != NULL)
-   {
-      struct buffer_list *next = list->next;
-      DELETE(list);
-      buffer_destroy_list(next);
-   }
-}
-
-static void
-buffer_destroy(struct buffer *buffer)
-{
-   struct buffer_list *list = buffer->first.next;
-   buffer_init(buffer);
-   buffer_destroy_list(list);
-}
-
 #ifdef PNG_WRITE_SUPPORTED
 static void
 buffer_start_write(struct buffer *buffer)
@@ -412,6 +390,8 @@ get_buffer(png_structp pp)
   return (struct buffer*)png_get_io_ptr(pp);
 }

+#define NEW(type) ((type *)malloc(sizeof (type)))
+
 static struct buffer_list *
 buffer_extend(struct buffer_list *current)
 {
@@ -618,17 +598,6 @@ display_clean(struct display *dp)
   dp->results = 0; /* reset for next time */
 }

-static void
-display_destroy(struct display *dp)
-{
-    /* Release any memory held in the display. */
-#  ifdef PNG_WRITE_SUPPORTED
-      buffer_destroy(&dp->written_file);
-#  endif
-
-   buffer_destroy(&dp->original_file);
-}
-
 static struct display *
 get_dp(png_structp pp)
   /* The display pointer is always stored in the png_struct error pointer */
@@ -1636,9 +1605,6 @@ main(const int argc, const char * const * const argv)
         display_clean(&d);
      }

-      /* Release allocated memory */
-      display_destroy(&d);
-
      return errors != 0;
   }
 }
--- a/contrib/libtests/pngstest.c
+++ b/contrib/libtests/pngstest.c
@@ -1,9 +1,9 @@
 /*-
 * pngstest.c
 *
- * Copyright (c) 2013-2014 John Cunningham Bowler
+ * Copyright (c) 2013 John Cunningham Bowler
 *
- * Last changed in libpng 1.6.16 [December 22, 2014]
+ * Last changed in libpng 1.6.8 [December 19, 2013]
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
@@ -3173,43 +3173,32 @@ read_one_file(Image *image)
            {
               long int cb = ftell(f);

-               if (cb > 0)
+               if (cb > 0 && (unsigned long int)cb < (size_t)~(size_t)0)
               {
-                  if ((unsigned long int)cb <= (size_t)~(size_t)0)
+                  png_bytep b = voidcast(png_bytep, malloc((size_t)cb));
+
+                  if (b != NULL)
                  {
-                     png_bytep b = voidcast(png_bytep, malloc((size_t)cb));
+                     rewind(f);

-                     if (b != NULL)
+                     if (fread(b, (size_t)cb, 1, f) == 1)
                     {
-                        rewind(f);
-
-                        if (fread(b, (size_t)cb, 1, f) == 1)
-                        {
-                           fclose(f);
-                           image->input_memory_size = cb;
-                           image->input_memory = b;
-                        }
-
-                        else
-                        {
-                           free(b);
-                           return logclose(image, f, image->file_name,
-                              ": read failed: ");
-                        }
+                        fclose(f);
+                        image->input_memory_size = cb;
+                        image->input_memory = b;
                     }

                     else
+                     {
+                        free(b);
                        return logclose(image, f, image->file_name,
-                           ": out of memory: ");
+                           ": read failed: ");
+                     }
                  }

                  else
                     return logclose(image, f, image->file_name,
-                        ": file too big for this architecture: ");
-                     /* cb is the length of the file as a (long) and
-                      * this is greater than the maximum amount of
-                      * memory that can be requested from malloc.
-                      */
+                        ": out of memory: ");
               }

               else if (cb == 0)
--- a/contrib/libtests/pngvalid.c
+++ b/contrib/libtests/pngvalid.c
--- a/contrib/pngminim/decoder/makefile
+++ b/contrib/pngminim/decoder/makefile
@@ -82,7 +82,7 @@ OBJS    = $(PROGOBJS) $(PNGOBJS) $(ZOBJS)

 # note: dependencies do not work on implicit rule lines
 .c$(O):
-	$(CC) $(CPPFLAGS) -c $(CFLAGS) $<
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<

 # dependencies

--- a/contrib/pngminim/encoder/makefile
+++ b/contrib/pngminim/encoder/makefile
@@ -81,7 +81,7 @@ OBJS    = $(PROGOBJS) $(PNGOBJS) $(ZOBJS)
 # implicit make rules -------------------------------------------------------

 .c$(O):
-	$(CC) $(CPPFLAGS) -c $(CFLAGS) $<
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<

 # dependencies

--- a/contrib/pngminim/preader/makefile
+++ b/contrib/pngminim/preader/makefile
@@ -97,7 +97,7 @@ OBJS    = $(PROGOBJS) $(PNGOBJS) $(ZOBJS)
 # implicit make rules -------------------------------------------------------

 .c$(O):
-	$(CC) $(CPPFLAGS) -c $(CFLAGS) $<
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<

 # dependencies

--- a/contrib/pngminus/makefile.std
+++ b/contrib/pngminus/makefile.std
@@ -8,9 +8,9 @@ LD=$(CC)
 RM=rm -f

 #PNGPATH = /usr/local
-#PNGINC = -I$(PNGPATH)/include/libpng17
-#PNGLIB = -L$(PNGPATH)/lib -lpng17
-#PNGLIBS = $(PNGPATH)/lib/libpng17.a
+#PNGINC = -I$(PNGPATH)/include/libpng16
+#PNGLIB = -L$(PNGPATH)/lib -lpng16
+#PNGLIBS = $(PNGPATH)/lib/libpng16.a
 PNGINC = -I../..
 PNGLIB = -L../.. -lpng
 PNGLIBS = ../../libpng.a
@@ -23,7 +23,8 @@ ZINC = -I../../../zlib
 ZLIB = -L../../../zlib -lz
 ZLIBS = ../../../zlib/libz.a

-CFLAGS=$(PNGINC) $(ZINC)
+CPPFLAGS=$(PNGINC) $(ZINC)
+CFLAGS=
 LDLIBS=$(PNGLIB) $(ZLIB)
 LDLIBSS=$(PNGLIBS) $(ZLIBS)
 C=.c
@@ -37,7 +38,7 @@ E=
 all: png2pnm$(E) pnm2png$(E) png2pnm-static$(E) pnm2png-static$(E)

 png2pnm$(O): png2pnm$(C)
-	$(CC) -c $(CFLAGS) png2pnm$(C)
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) png2pnm$(C)

 png2pnm$(E): png2pnm$(O)
 	$(LD) $(LDFLAGS) -o png2pnm$(E) png2pnm$(O) $(LDLIBS) -lm
@@ -46,7 +47,7 @@ png2pnm-static$(E): png2pnm$(O)
 	$(LD) $(LDFLAGS) -o png2pnm-static$(E) png2pnm$(O) $(LDLIBSS) -lm

 pnm2png$(O): pnm2png$(C)
-	$(CC) -c $(CFLAGS) pnm2png$(C)
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) pnm2png$(C)

 pnm2png$(E): pnm2png$(O)
 	$(LD) $(LDFLAGS) -o pnm2png$(E) pnm2png$(O) $(LDLIBS) -lm
--- a/contrib/pngminus/makefile.tc3
+++ b/contrib/pngminus/makefile.tc3
@@ -7,7 +7,8 @@ LB=tlib
 RM=del
 CP=copy
 MODEL=l
-CCFLAGS=-O -m$(MODEL) -I..\libpng -I..\zlib
+CPPFLAGS=-I..\libpng -I..\zlib
+CFLAGS=-O -m$(MODEL)
 LDFLAGS=-m$(MODEL) -L..\libpng -L..\zlib
 C=.c
 O=.obj
@@ -19,13 +20,13 @@ E=.exe
 all: png2pnm$(E) pnm2png$(E)

 png2pnm$(O): png2pnm$(C)
-        $(CC) -c $(CCFLAGS) png2pnm$(C)
+        $(CC) -c $(CPPFLAGS) $(CFLAGS) png2pnm$(C)

 png2pnm$(E): png2pnm$(O)
        $(LD) $(LDFLAGS) png2pnm$(O) libpng$(L) zlib$(L)

 pnm2png$(O): pnm2png$(C)
-        $(CC) -c $(CCFLAGS) pnm2png$(C)
+        $(CC) -c $(CPPFLAGS) $(CFLAGS) pnm2png$(C)

 pnm2png$(E): pnm2png$(O)
        $(LD) $(LDFLAGS) pnm2png$(O) libpng$(L) zlib$(L)
@@ -35,4 +36,3 @@ clean:
        $(RM) *$(E)

 # End of makefile for png2pnm / pnm2png
-
--- a/contrib/pngminus/png2pnm.c
+++ b/contrib/pngminus/png2pnm.c
@@ -52,7 +52,8 @@

 int  main (int argc, char *argv[]);
 void usage ();
-BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL alpha);
+BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw,
+   BOOL alpha);

 /*
 *  main
@@ -85,7 +86,8 @@ int main(int argc, char *argv[])
          if ((fp_al = fopen (argv[argi], "wb")) == NULL)
          {
            fprintf (stderr, "PNM2PNG\n");
-            fprintf (stderr, "Error:  can not create alpha-channel file %s\n", argv[argi]);
+            fprintf (stderr, "Error:  can not create alpha-channel file %s\n",
+               argv[argi]);
            exit (1);
          }
          break;
@@ -176,9 +178,11 @@ void usage()
  fprintf (stderr, "Usage:  png2pnm [options] <file>.png [<file>.pnm]\n");
  fprintf (stderr, "   or:  ... | png2pnm [options]\n");
  fprintf (stderr, "Options:\n");
-  fprintf (stderr, "   -r[aw]   write pnm-file in binary format (P4/P5/P6) (default)\n");
+  fprintf (stderr,
+     "   -r[aw]   write pnm-file in binary format (P4/P5/P6) (default)\n");
  fprintf (stderr, "   -n[oraw] write pnm-file in ascii format (P1/P2/P3)\n");
-  fprintf (stderr, "   -a[lpha] <file>.pgm write PNG alpha channel as pgm-file\n");
+  fprintf (stderr,
+     "   -a[lpha] <file>.pgm write PNG alpha channel as pgm-file\n");
  fprintf (stderr, "   -h | -?  print this help-information\n");
 }

@@ -186,7 +190,8 @@ void usage()
 *  png2pnm
 */

-BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL alpha)
+BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file,
+    volatile BOOL raw, BOOL alpha)
 {
  png_struct    *png_ptr = NULL;
  png_info        *info_ptr = NULL;
@@ -315,12 +320,14 @@ BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL a
  /* row_bytes is the width x number of channels x (bit-depth / 8) */
  row_bytes = png_get_rowbytes (png_ptr, info_ptr);

-  if ((png_pixels = (png_byte *) malloc (row_bytes * height * sizeof (png_byte))) == NULL) {
+  if ((png_pixels = (png_byte *)
+     malloc (row_bytes * height * sizeof (png_byte))) == NULL) {
    png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
    return FALSE;
  }

-  if ((row_pointers = (png_byte **) malloc (height * sizeof (png_bytep))) == NULL)
+  if ((row_pointers = (png_byte **)
+     malloc (height * sizeof (png_bytep))) == NULL)
  {
    png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
    free (png_pixels);
@@ -329,7 +336,7 @@ BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL a
  }

  /* set the individual row_pointers to point at the correct offsets */
-  for (i = 0; i < (height); i++)
+  for (i = 0; i < ((int) height); i++)
    row_pointers[i] = png_pixels + i * row_bytes;

  /* now we can go ahead and just read the whole image */
@@ -372,9 +379,9 @@ BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL a
  /* write data to PNM file */
  pix_ptr = png_pixels;

-  for (row = 0; row < height; row++)
+  for (row = 0; row < (int) height; row++)
  {
-    for (col = 0; col < width; col++)
+    for (col = 0; col < (int) width; col++)
    {
      for (i = 0; i < (channels - alpha_present); i++)
      {
--- a/contrib/pngminus/pnm2png.c
+++ b/contrib/pngminus/pnm2png.c
@@ -50,7 +50,8 @@

 int  main (int argc, char *argv[]);
 void usage ();
-BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace, BOOL alpha);
+BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,
+    BOOL alpha);
 void get_token(FILE *pnm_file, char *token);
 png_uint_32 get_data (FILE *pnm_file, int depth);
 png_uint_32 get_value (FILE *pnm_file, int depth);
@@ -176,7 +177,8 @@ void usage()
  fprintf (stderr, "   or:  ... | pnm2png [options]\n");
  fprintf (stderr, "Options:\n");
  fprintf (stderr, "   -i[nterlace]   write png-file with interlacing on\n");
-  fprintf (stderr, "   -a[lpha] <file>.pgm read PNG alpha channel as pgm-file\n");
+  fprintf (stderr,
+      "   -a[lpha] <file>.pgm read PNG alpha channel as pgm-file\n");
  fprintf (stderr, "   -h | -?  print this help-information\n");
 }

@@ -184,27 +186,28 @@ void usage()
 *  pnm2png
 */

-BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace, BOOL alpha)
+BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,
+     BOOL alpha)
 {
  png_struct    *png_ptr = NULL;
  png_info      *info_ptr = NULL;
  png_byte      *png_pixels = NULL;
  png_byte      **row_pointers = NULL;
  png_byte      *pix_ptr = NULL;
-  png_uint_32   row_bytes;
+  volatile png_uint_32   row_bytes;

  char          type_token[16];
  char          width_token[16];
  char          height_token[16];
  char          maxval_token[16];
-  int           color_type;
+  volatile int           color_type;
  unsigned long   ul_width=0, ul_alpha_width=0;
  unsigned long   ul_height=0, ul_alpha_height=0;
  unsigned long   ul_maxval=0;
-  png_uint_32   width, alpha_width;
-  png_uint_32   height, alpha_height;
+  volatile png_uint_32   width, height;
+  volatile png_uint_32   alpha_width, alpha_height;
  png_uint_32   maxval;
-  int           bit_depth = 0;
+  volatile int           bit_depth = 0;
  int           channels;
  int           alpha_depth = 0;
  int           alpha_present;
@@ -367,23 +370,24 @@ BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,
    /* row_bytes is the width x number of channels x (bit-depth / 8) */
    row_bytes = width * channels * ((bit_depth <= 8) ? 1 : 2);

-  if ((png_pixels = (png_byte *) malloc (row_bytes * height * sizeof (png_byte))) == NULL)
+  if ((png_pixels = (png_byte *)
+     malloc (row_bytes * height * sizeof (png_byte))) == NULL)
    return FALSE;

  /* read data from PNM file */
  pix_ptr = png_pixels;

-  for (row = 0; row < height; row++)
+  for (row = 0; row < (int) height; row++)
  {
 #if defined(PNG_WRITE_INVERT_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
    if (packed_bitmap) {
-      for (i = 0; i < row_bytes; i++)
+      for (i = 0; i < (int) row_bytes; i++)
        /* png supports this format natively so no conversion is needed */
        *pix_ptr++ = get_data (pnm_file, 8);
    } else
 #endif
    {
-      for (col = 0; col < width; col++)
+      for (col = 0; col < (int) width; col++)
      {
        for (i = 0; i < (channels - alpha_present); i++)
        {
@@ -462,7 +466,8 @@ BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,
  /* if needed we will allocate memory for an new array of row-pointers */
  if (row_pointers == (unsigned char**) NULL)
  {
-    if ((row_pointers = (png_byte **) malloc (height * sizeof (png_bytep))) == NULL)
+    if ((row_pointers = (png_byte **)
+        malloc (height * sizeof (png_bytep))) == NULL)
    {
      png_destroy_write_struct (&png_ptr, (png_infopp) NULL);
      return FALSE;
@@ -470,13 +475,13 @@ BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,
  }

  /* set the individual row_pointers to point at the correct offsets */
-  for (i = 0; i < (height); i++)
+  for (i = 0; i < (int) height; i++)
    row_pointers[i] = png_pixels + i * row_bytes;

  /* write out the entire image data in one call */
  png_write_image (png_ptr, row_pointers);

-  /* write the additional chuncks to the PNG file (not really needed) */
+  /* write the additional chunks to the PNG file (not really needed) */
  png_write_end (png_ptr, info_ptr);

  /* clean up after the write, and free any memory allocated */
--- a/contrib/tools/chunkhash.c
+++ b/contrib/tools/chunkhash.c
@@ -1,437 +0,0 @@
-/* chunkhash.c -- build a perfect hash code for the chunk names on stdin.
- *
- * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- *
- * COPYRIGHT: Written by John Cunningham Bowler, 2014.
- * To the extent possible under law, the author has waived all copyright and
- * related or neighboring rights to this work.  This work is published from:
- * United States.
- *
- * Feed this program all the known chunks that libpng must recognize.  It will
- * generate an appropriate hash key for the macro in pngpriv.h  To generate the
- * list of chunks currently defined in png.h do this:
- *
- *    sed -n -e 's/^#define png_\(....\) PNG_U32.*$/\1/p' png.h
- *
- * An alternative to using this program is to pipe the output of the above
- * through gperf, however the code generated by perf is somewhat more verbose
- * and it doesn't generate as good a result (however it's a heck of a lot faster
- * than this program!)
- */
-#include <stdio.h>
-#include <string.h>
-#include <stdlib.h>
-#include <png.h> /* for the libpng types for this platform */
-
-/* The machine generated file is checked in, so this works and it obtains the
- * definition of the PNG_CHUNK_HASH macro.  To change this definition only ever
- * alter the strings below!
- */
-#include "chunkhash.h"
-
-/* The best_ variables are local variables defined in the functions below.  When
- * used in libpng code, however, they are just constants.
- */
-#define PNG_CHUNK_HASH_MASK best_mask
-#define PNG_CHUNK_HASH_C0 best_c[0]
-#define PNG_CHUNK_HASH_C1 best_c[1]
-#define PNG_CHUNK_HASH_C2 best_c[2]
-#define PNG_CHUNK_HASH_C3 best_c[3]
-
-/* These strings contain the C text to copy into the new version of
- * contrib/tools/chunkhash.c
- */
-static const char *strings[] = {
-"/* chunkhash.h -- a perfect hash code for the chunk names in png.h",
-" *",
-" * Last changed in libpng 1.7.0 [(PENDING RELEASE)]",
-" *",
-" * THIS IS A MACHINE GENERATED FILE.  See contrib/tools/chunkhash.c for",
-" * copyright and other information.",
-" *",
-" * USAGE:  To include the PNG_CHUNK_HASH macro and associated definitions:",
-" *",
-" * #define PNG_CHUNKHASH_DEFS",
-" * #include \"contrib/tools/chunkhash.h\"",
-" *",
-" * To define the png_chunk_hash array used by the macro:",
-" *",
-" * #define PNG_CHUNKHASH_CODE",
-" * #include \"contrib/tools/chunkhash.h\"",
-" *",
-" * One or both of the defines must be given except when building chunkhash",
-" * itself.",
-" */",
-"#ifdef PNG_CHUNKHASH_DEFS",
-"#ifndef PNG_CHUNKHASH_H",
-"#define PNG_CHUNKHASH_H",
-"/* A perfect hash code - returns a value 0..(PNG_KNOWN_CHUNK_COUNT-1) and is",
-" * generated by the ridiculously simple program in contrib/tools/chunkhash.c",
-" *",
-" * The hash code used here multiplies each byte by a different constant to",
-" * return a single number:",
-" *",
-" *    b0 * c[0] + b1 * [c1] + b2 * c[2] + b3 * c[3]",
-" *",
-" * The values of the constants are found by search using the a table of",
-" * primes, including 0, and may be (in fact are at present) 0 for some of the",
-" * bytes, the compiler is expected to optimize multiply by zero, or one!",
-" *",
-" * The lookup table reduces the sparse result of the hash calculation to the",
-" * correct index values.  The chunks are indexed in the string order of the",
-" * png_uint_32 chunk names.",
-" */",
-0, /* HEADER definitions go here */
-"",
-"extern const png_byte png_chunk_hash[PNG_CHUNK_HASH_MASK+1];",
-"#endif /* !PNG_CHUNKHASH_H */",
-"#endif /* PNG_CHUNKHASH_DEFS */",
-"",
-"#ifndef PNG_CHUNK_HASH",
-"#define PNG_CHUNK_HASH(chunk) (png_chunk_hash[PNG_CHUNK_HASH_MASK & (\\",
-"      ((chunk) >> 24) * PNG_CHUNK_HASH_C0 +\\",
-"      ((chunk) >> 16) * PNG_CHUNK_HASH_C1 +\\",
-"      ((chunk) >>  8) * PNG_CHUNK_HASH_C2 +\\",
-"      ((chunk)      ) * PNG_CHUNK_HASH_C3)])",
-"#endif",
-"",
-"#ifdef PNG_CHUNKHASH_CODE",
-"#ifndef PNG_CHUNKHASH_C",
-"#define PNG_CHUNKHASH_C",
-"const png_byte png_chunk_hash[PNG_CHUNK_HASH_MASK+1] = {",
-0, /* png.c definitions go here */
-"};",
-"#endif /* !PNG_CHUNKHASH_C */",
-"#endif /* PNG_CHUNKHASH_CODE */",
-0 /* end of file */
-};
-
-#define CHUNK_COUNT_MAX 32
-   /* If necessary this is easy to increase; just don't use a png_uint_32
-    * bitmask below, however it doesn't seem likely that the limit will be hit
-    * any time soon.
-    */
-
-static const png_byte
-chunk_hash[256] =
-{
-   0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21,
-   22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
-   41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59,
-   60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78,
-   79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97,
-   98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113,
-   114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128,
-   129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143,
-   144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158,
-   159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173,
-   174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188,
-   189, 190, 191, 192, 193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203,
-   204, 205, 206, 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218,
-   219, 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 230, 231, 232, 233,
-   234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, 246, 247, 248,
-   249, 250, 251, 252, 253, 254, 255
-};
-
-static void
-error(const char *string)
-{
-   fprintf(stderr, "chunkhash: %s\n", string);
-   exit(1);
-}
-
-/* Return a hash code for the given chunk; this is the same as the pngpriv.h
- * macro, but parameterized.  The names of the parameters have to be chosen to
- * match the above #defines.
- */
-static png_uint_32
-test_hash(png_uint_32 chunk, const unsigned int *best_c, png_uint_32 best_mask)
-{
-#  define png_chunk_hash chunk_hash /* prevents lookup */
-      return PNG_CHUNK_HASH(chunk);
-#  undef png_chunk_hash
-}
-
-static void
-print_chunks(const png_uint_32 *chunks, unsigned int nchunks, png_uint_32 first,
-   png_uint_32 last, const unsigned int *best_c, png_uint_32 best_mask,
-   const png_byte *lut)
-{
-   /* 'last' is the last code to print plus 1, this is used to detect duplicates
-    * (which should not happen - if there are any it's an internal error!)
-    */
-   if (nchunks > 0)
-   {
-      /* Recursive algorithm; find the hash code of the next chunk, then print
-       * all remaining chunks with codes in the range first..code (including
-       * duplicates) and after print all remaining chunks with codes in the
-       * range (code+1)..last
-       */
-      const png_uint_32 chunk = *chunks++;
-#     define png_chunk_hash lut
-         const png_uint_32 code = PNG_CHUNK_HASH(chunk);
-#     undef png_chunk_hash
-
-      --nchunks;
-
-      /* The code might be out of the print range */
-      if (code >= first && code <= last)
-      {
-         if (code >= first) /* not time yet */
-            print_chunks(chunks, nchunks, first, code, best_c, best_mask, lut);
-
-         printf("#define PNG_CHUNK_%c%c%c%c_TAG %lu%s\n", (char)(chunk>>24),
-            (char)(chunk>>16), (char)(chunk>>8), (char)chunk,
-            (unsigned long)code, code == last ? " /* DUPLICATE */" : "");
-
-         if (code < last) /* still some to go */
-            print_chunks(chunks, nchunks, code+1, last, best_c, best_mask, lut);
-      }
-
-      else
-         print_chunks(chunks, nchunks, first, last, best_c, best_mask, lut);
-   }
-}
-
-static unsigned int primes[] =
-{
-   0, 1, 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67,
-   71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149,
-   151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229,
-   233, 239, 241, 251
-};
-
-#define NPRIMES ((sizeof primes)/(sizeof primes[0]))
-
-int
-main(void)
-{
-   /* Stdin should just contain chunk names, one per line */
-   png_uint_32 best_mask;
-   unsigned int best_c[4];
-   png_uint_32 chunks[CHUNK_COUNT_MAX];
-   png_byte known_chunk_count;
-
-   /* Not required; stop GCC whining: */
-   memset(best_c, 0xab, sizeof best_c);
-   best_mask = 0x12345678;
-
-   {
-      png_uint_32 this_chunk = 0;
-      png_byte n_chunks = 0;
-
-      for (;;)
-      {
-         int ch = getchar();
-
-         if ((ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z'))
-         {
-            if (this_chunk > 0xffffffU)
-               error("chunk name too long");
-
-            this_chunk = (this_chunk << 8) + (unsigned)ch;
-         }
-
-         else
-         {
-            if (this_chunk > 0)
-            {
-               if (this_chunk <= 0xffffffU)
-                  error("chunk name too short");
-
-               if (n_chunks >= CHUNK_COUNT_MAX)
-                  error("too many chunks (check CHUNK_COUNT_MAX)");
-
-               chunks[n_chunks++] = this_chunk;
-               this_chunk = 0;
-            }
-         }
-
-         if (ch < 0)
-            break;
-      }
-
-      /* 22 is the number of chunks currently defined (excluding fRAc), at any
-       * time it should also be in PNG_KNOWN_CHUNK_COUNT, but this run of
-       * chunkhash may be trying to add a chunk so allow bigger numbers.
-       */
-#     ifdef PNG_KNOWN_CHUNK_COUNT
-#        define CHUNK_COUNT_MIN PNG_KNOWN_CHUNK_COUNT
-#     else
-#        define CHUNK_COUNT_MIN 26
-#     endif
-      if (n_chunks < CHUNK_COUNT_MIN)
-         error("too few chunks (expecting at least 26)");
-
-      known_chunk_count = n_chunks;
-   }
-
-   /* Exhaustive search of the hash parameters - in fact this isn't very slow at
-    * all.
-    */
-   {
-      unsigned int i1, c_zero = 0, c_one = 0;
-
-      for (i1=0; i1<NPRIMES; ++i1)
-      {
-         unsigned int i2;
-         unsigned int c[4];
-
-         fprintf(stderr, "TEST: %u\n", primes[i1]);
-         c[0] = primes[i1];
-
-         for (i2=0; i2<NPRIMES; ++i2)
-         {
-            unsigned int i3;
-
-            c[1] = primes[i2];
-
-            for (i3=0; i3<NPRIMES; ++i3)
-            {
-               unsigned int i4;
-
-               c[2] = primes[i3];
-
-               for (i4=0; i4<NPRIMES; ++i4)
-               {
-                  unsigned int i;
-                  png_uint_32 hash_mask = 0xffU;
-                  png_uint_32 hashes[CHUNK_COUNT_MAX];
-
-                  c[3] = primes[i4];
-
-                  while (hash_mask > 0xfU)
-                  {
-                     for (i=0; i<known_chunk_count; ++i)
-                     {
-                        unsigned int j;
-                        png_uint_32 hash = test_hash(chunks[i], c, hash_mask);
-
-                        for (j=0; j<i; ++j) if (hashes[j] == hash) goto next_i4;
-
-                        hashes[i] = hash;
-                     }
-
-                     hash_mask >>= 1;
-                  }
-
-               next_i4:
-                  if (hash_mask < 0xffU)
-                  {
-                     /* This worked */
-                     unsigned int best, c0 = 0, c1 = 0;
-
-                     hash_mask <<= 1;
-                     hash_mask += 1;
-
-                     for (i=0; i<4; ++i)
-                     {
-                        if (c[i] == 0)
-                           ++c0;
-
-                        else if (c[i] == 1)
-                           ++c1;
-                     }
-
-                     if (hash_mask == best_mask)
-                        best = (c0 > c_zero) || (c0 == c_zero && c1 > c_one);
-
-                     else
-                        best = (hash_mask < best_mask);
-
-                     if (best)
-                     {
-                        fprintf(stderr, "{%u,%u,%u,%u} & 0x%lx\n",
-                           c[0], c[1], c[2], c[3],
-                           (unsigned long)hash_mask);
-
-                        c_zero = c0;
-                        c_one = c1;
-                        best_mask = hash_mask;
-                        memcpy(best_c, c, sizeof best_c);
-                     }
-                  }
-               } /* i4 */
-            } /* i3 */
-         } /* i2 */
-      } /* i1 */
-   }
-
-   /* Calculate the LUT (png_chunk_hash) */
-   {
-      png_byte b;
-      png_byte lut[256];
-
-      /* A failure returns PNG_KNOWN_CHUNK_COUNT: */
-      memset(lut, known_chunk_count, sizeof lut);
-
-      for (b=0; b<known_chunk_count; ++b)
-         lut[test_hash(chunks[b], best_c, best_mask)] = b;
-
-      /* Validate the pngpriv.h hash function. */
-#     define png_chunk_hash lut
-         {
-            unsigned int i;
-
-            for (i=0; i<known_chunk_count; ++i)
-            {
-               png_uint_32 chunk = chunks[i];
-
-               if (PNG_CHUNK_HASH(chunk) != i)
-                  error("internal error: hash didn't work!");
-            }
-         }
-#     undef lut
-
-      /* Print all the results, first the stuff for pngpriv.h */
-      {
-         unsigned int i = 0;
-
-         while (strings[i] != 0)
-            puts(strings[i++]);
-
-         printf("#define PNG_CHUNK_HASH_MASK 0x%lxU\n",
-            (unsigned long)best_mask);
-         printf("#define PNG_CHUNK_HASH_C0 %u\n", best_c[0]);
-         printf("#define PNG_CHUNK_HASH_C1 %u\n", best_c[1]);
-         printf("#define PNG_CHUNK_HASH_C2 %u\n", best_c[2]);
-         printf("#define PNG_CHUNK_HASH_C3 %u\n", best_c[3]);
-
-         /* Print the hash codes of all the chunks */
-         putchar('\n');
-         print_chunks(chunks, known_chunk_count, 0, 0xffffffff, best_c,
-            best_mask, lut);
-         putchar('\n');
-         printf("#define PNG_KNOWN_CHUNK_COUNT %u\n", known_chunk_count);
-
-         while (strings[++i] != 0)
-            puts(strings[i]);
-
-         /* Now print the LUT */
-         fputs("   ", stdout);
-         {
-            unsigned int j;
-
-            for (j=0; j<=best_mask; ++j)
-            {
-               printf("%d", lut[j]);
-
-               if ((j % 16) == 15 && j < best_mask)
-                  printf(",\n   ");
-
-               else if (j < best_mask)
-                  printf(", ");
-
-               else
-                  printf("\n");
-            }
-         }
-
-         /* And the trailing text */
-         while (strings[++i] != 0)
-            puts(strings[i]);
-      }
-   }
-
-   exit(0);
-}
--- a/contrib/tools/chunkhash.h
+++ b/contrib/tools/chunkhash.h
@@ -1,97 +0,0 @@
-/* chunkhash.h -- a perfect hash code for the chunk names in png.h
- *
- * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- *
- * THIS IS A MACHINE GENERATED FILE.  See contrib/tools/chunkhash.c for
- * copyright and other information.
- *
- * USAGE:  To include the PNG_CHUNK_HASH macro and associated definitions:
- *
- * #define PNG_CHUNKHASH_DEFS
- * #include "contrib/tools/chunkhash.h"
- *
- * To define the png_chunk_hash array used by the macro:
- *
- * #define PNG_CHUNKHASH_CODE
- * #include "contrib/tools/chunkhash.h"
- *
- * One or both of the defines must be given except when building chunkhash
- * itself.
- */
-#ifdef PNG_CHUNKHASH_DEFS
-#ifndef PNG_CHUNKHASH_H
-#define PNG_CHUNKHASH_H
-/* A perfect hash code - returns a value 0..(PNG_KNOWN_CHUNK_COUNT-1) and is
- * generated by the ridiculously simple program in contrib/tools/chunkhash.c
- *
- * The hash code used here multiplies each byte by a different constant to
- * return a single number:
- *
- *    b0 * c[0] + b1 * [c1] + b2 * c[2] + b3 * c[3]
- *
- * The values of the constants are found by search using the a table of
- * primes, including 0, and may be (in fact are at present) 0 for some of the
- * bytes, the compiler is expected to optimize multiply by zero, or one!
- *
- * The lookup table reduces the sparse result of the hash calculation to the
- * correct index values.  The chunks are indexed in the string order of the
- * png_uint_32 chunk names.
- */
-#define PNG_CHUNK_HASH_MASK 0x3fU
-#define PNG_CHUNK_HASH_C0 103
-#define PNG_CHUNK_HASH_C1 1
-#define PNG_CHUNK_HASH_C2 0
-#define PNG_CHUNK_HASH_C3 1
-
-#define PNG_CHUNK_IDAT_TAG 0
-#define PNG_CHUNK_IEND_TAG 1
-#define PNG_CHUNK_IHDR_TAG 2
-#define PNG_CHUNK_PLTE_TAG 3
-#define PNG_CHUNK_bKGD_TAG 4
-#define PNG_CHUNK_cHRM_TAG 5
-#define PNG_CHUNK_fRAc_TAG 6
-#define PNG_CHUNK_gAMA_TAG 7
-#define PNG_CHUNK_gIFg_TAG 8
-#define PNG_CHUNK_gIFt_TAG 9
-#define PNG_CHUNK_gIFx_TAG 10
-#define PNG_CHUNK_hIST_TAG 11
-#define PNG_CHUNK_iCCP_TAG 12
-#define PNG_CHUNK_iTXt_TAG 13
-#define PNG_CHUNK_oFFs_TAG 14
-#define PNG_CHUNK_pCAL_TAG 15
-#define PNG_CHUNK_pHYs_TAG 16
-#define PNG_CHUNK_sBIT_TAG 17
-#define PNG_CHUNK_sCAL_TAG 18
-#define PNG_CHUNK_sPLT_TAG 19
-#define PNG_CHUNK_sRGB_TAG 20
-#define PNG_CHUNK_sTER_TAG 21
-#define PNG_CHUNK_tEXt_TAG 22
-#define PNG_CHUNK_tIME_TAG 23
-#define PNG_CHUNK_tRNS_TAG 24
-#define PNG_CHUNK_zTXt_TAG 25
-
-#define PNG_KNOWN_CHUNK_COUNT 26
-
-extern const png_byte png_chunk_hash[PNG_CHUNK_HASH_MASK+1];
-#endif /* !PNG_CHUNKHASH_H */
-#endif /* PNG_CHUNKHASH_DEFS */
-
-#ifndef PNG_CHUNK_HASH
-#define PNG_CHUNK_HASH(chunk) (png_chunk_hash[PNG_CHUNK_HASH_MASK & (\
-      ((chunk) >> 24) * PNG_CHUNK_HASH_C0 +\
-      ((chunk) >> 16) * PNG_CHUNK_HASH_C1 +\
-      ((chunk) >>  8) * PNG_CHUNK_HASH_C2 +\
-      ((chunk)      ) * PNG_CHUNK_HASH_C3)])
-#endif
-
-#ifdef PNG_CHUNKHASH_CODE
-#ifndef PNG_CHUNKHASH_C
-#define PNG_CHUNKHASH_C
-const png_byte png_chunk_hash[PNG_CHUNK_HASH_MASK+1] = {
-   26, 3, 26, 26, 26, 26, 26, 13, 26, 26, 26, 16, 26, 26, 26, 26,
-   26, 24, 12, 26, 18, 26, 26, 26, 26, 20, 26, 17, 26, 26, 25, 15,
-   26, 8, 14, 26, 26, 22, 26, 26, 1, 19, 5, 21, 26, 26, 9, 26,
-   26, 26, 10, 7, 26, 11, 26, 0, 26, 2, 23, 26, 26, 4, 26, 6
-};
-#endif /* !PNG_CHUNKHASH_C */
-#endif /* PNG_CHUNKHASH_CODE */
--- a/contrib/tools/intgamma.sh
+++ b/contrib/tools/intgamma.sh
--- a/contrib/tools/pngfix.c
+++ b/contrib/tools/pngfix.c
@@ -1,15 +1,15 @@
 /* pngfix.c
 *
- * Copyright (c) 2015 John Cunningham Bowler
+ * Copyright (c) 2014 John Cunningham Bowler
 *
- * Last changed in libpng 1.6.17 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.10 [March 6, 2014]
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
 * and license in png.h
 *
- * Tool to check and fix the zlib inflate 'too far back' problem.
- * See the usage message for more information.
+ * Tool to check and fix the zlib inflate 'too far back' problem, see the usage
+ * message for more information.
 */
 #include <stdlib.h>
 #include <stdio.h>
@@ -49,9 +49,6 @@
 #  error "pngfix will not work with libpng prior to 1.6.3"
 #endif

-#ifdef PNG_SETJMP_SUPPORTED
-#include <setjmp.h>
-
 #if defined(PNG_READ_SUPPORTED) && defined(PNG_EASY_ACCESS_SUPPORTED)
 /* zlib.h defines the structure z_stream, an instance of which is included
 * in this structure and is required for decompressing the LZ compressed
@@ -3577,6 +3574,7 @@ read_png(struct control *control)
 {
   png_structp png_ptr;
   png_infop info_ptr = NULL;
+   volatile png_bytep row = NULL, display = NULL;
   volatile int rc;

   png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, control,
@@ -3593,16 +3591,6 @@ read_png(struct control *control)
   rc = setjmp(control->file.jmpbuf);
   if (rc == 0)
   {
-#     ifdef PNG_SET_USER_LIMITS_SUPPORTED
-         /* Remove any limits on the size of PNG files that can be read,
-          * without this we may reject files based on built-in safety
-          * limits.
-          */
-         png_set_user_limits(png_ptr, 0x7fffffff, 0x7fffffff);
-         png_set_chunk_cache_max(png_ptr, 0);
-         png_set_chunk_malloc_max(png_ptr, 0);
-#     endif
-
      png_set_read_fn(png_ptr, control, read_callback);

      info_ptr = png_create_info_struct(png_ptr);
@@ -3615,22 +3603,32 @@ read_png(struct control *control)
      png_read_info(png_ptr, info_ptr);

      {
-        png_uint_32 height = png_get_image_height(png_ptr, info_ptr);
-        int passes = png_set_interlace_handling(png_ptr);
-        int pass;
+         png_size_t rowbytes = png_get_rowbytes(png_ptr, info_ptr);

-        png_start_read_image(png_ptr);
+         row = png_voidcast(png_byte*, malloc(rowbytes));
+         display = png_voidcast(png_byte*, malloc(rowbytes));

-        for (pass = 0; pass < passes; ++pass)
-        {
-           png_uint_32 y = height;
+         if (row == NULL || display == NULL)
+            png_error(png_ptr, "OOM allocating row buffers");

-           /* NOTE: this skips asking libpng to return either version of
-            * the image row, but libpng still reads the rows.
-            */
-           while (y-- > 0)
-              png_read_row(png_ptr, NULL, NULL);
-        }
+         {
+            png_uint_32 height = png_get_image_height(png_ptr, info_ptr);
+            int passes = png_set_interlace_handling(png_ptr);
+            int pass;
+
+            png_start_read_image(png_ptr);
+
+            for (pass = 0; pass < passes; ++pass)
+            {
+               png_uint_32 y = height;
+
+               /* NOTE: this trashes the row each time; interlace handling won't
+                * work, but this avoids memory thrashing for speed testing.
+                */
+               while (y-- > 0)
+                  png_read_row(png_ptr, row, display);
+            }
+         }
      }

      if (control->file.global->verbose)
@@ -3641,6 +3639,8 @@ read_png(struct control *control)
   }

   png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+   if (row != NULL) free(row);
+   if (display != NULL) free(display);
   return rc;
 }

@@ -4034,12 +4034,3 @@ main(void)
   return 77;
 }
 #endif /* PNG_READ_SUPPORTED && PNG_EASY_ACCESS_SUPPORTED */
-#else /* No setjmp support */
-int
-main(void)
-{
-   fprintf(stderr, "pngfix does not work without setjmp support\n");
-   return 77;
-}
-#endif /* PNG_SETJMP_SUPPORTED */
-
--- a/contrib/tools/scale.c
+++ b/contrib/tools/scale.c
@@ -1,238 +0,0 @@
-/* Given a target range and a source range work out an expression to scale from
- * the source to the target of the form:
- *
- *    (number * mult + add)>>16
- *
- * The command arguments are:
- *
- *    scale target source
- *
- * and the program works out a pair of numbers, mult and add, that evaluate:
- *
- *          number * target
- *   round( --------------- )
- *              source
- *
- * exactly for number in the range 0..source
- */
-#define _ISOC99_SOURCE 1
-
-#include <stdlib.h>
-#include <string.h>
-#include <stdio.h>
-#include <math.h>
-
-static double minerr;
-static unsigned long minmult, minadd, minshift;
-static long mindelta;
-
-static int
-test(unsigned long target, unsigned long source, unsigned long mult,
-   long add, unsigned long shift, long delta)
-{
-   unsigned long i;
-   double maxerr = 0;
-   double rs = (double)target/source;
-
-   for (i=0; i<=source; ++i)
-   {
-      unsigned long t = i*mult+add;
-      double err = fabs((t >> shift) - i*rs);
-
-      if (err > minerr)
-         return 0;
-
-      if (err > maxerr)
-         maxerr = err;
-   }
-
-   if (maxerr < minerr)
-   {
-      minerr = maxerr;
-      minmult = mult;
-      minadd = add;
-      minshift = shift;
-      mindelta = delta;
-   }
-
-   return maxerr < .5;
-}
-
-static int
-dotest(unsigned long target, unsigned long source, unsigned long mult,
-   long add, unsigned long shift, long delta, int print)
-{
-   if (test(target, source, mult, add, shift, delta))
-   {
-      if (print & 4)
-         printf("      {%11lu,%6ld /* >>%lu */ }, /* %lu/%lu */\n",
-            mult, add, shift, target, source);
-
-      else if (print & 2)
-         printf("      {%11lu,%6ld,%3lu }, /* %lu/%lu */\n",
-            mult, add, shift, target, source);
-
-      else if (print)
-         printf("number * %lu/%lu = (number * %lu + %ld) >> %lu [delta %ld]\n",
-            target, source, mult, add, shift, delta);
-
-      return 1;
-   }
-
-   return 0;
-}
-
-static int
-find(unsigned long target, unsigned long source, int print, int fixshift)
-{
-   unsigned long shift = 0;
-   unsigned long shiftlim = 0;
-
-   /* In the final math the sum is at most (source*mult+add) >> shift, so:
-    *
-    *    source*mult+add < 1<<32
-    *    mult < (1<<32)/source
-    *
-    * but:
-    *
-    *    mult = (target<<shift)/source
-    *
-    * so:
-    *
-    *    (target<<shift) < (1<<32)
-    */
-   if (fixshift < 0)
-      while ((target<<shiftlim) < 0x80000000U) ++shiftlim;
-
-   else
-      shift = shiftlim = (unsigned long)fixshift;
-
-   minerr = 1E8;
-
-   for (; shift<=shiftlim; ++shift)
-   {
-      unsigned long mult = ((target<<shift) + (source>>1)) / source;
-      long delta;
-      long limit = 1; /* seems to be sufficient */
-      long add, start, end;
-
-      end = 1<<shift;
-      start = -end;
-
-      for (add=start; add<=end; ++add)
-         if (dotest(target,source,mult,add,shift,0,print))
-            return 1;
-
-      for (delta=1; delta<=limit; ++delta)
-      {
-#        if 0
-            fprintf(stderr, "%lu/%lu: shift %lu, delta %lu\n", target, source,
-               shift, delta);
-#        endif
-
-         for (add=start; add<=end; ++add)
-         {
-            if (dotest(target, source, mult-delta, add, shift, -delta, print))
-               return 1;
-
-            if (dotest(target, source, mult+delta, add, shift, delta, print))
-               return 1;
-         }
-      }
-   }
-
-   if (print & 4)
-      printf("      {%11lu,%6ld /* >>%lu */ }, /* %lu/%lu ERROR: .5+%g*/\n",
-         minmult, minadd, minshift, target, source, minerr-.5);
-
-   else if (print & 2)
-      printf("      {%11lu,%6ld,%3lu }, /* %lu/%lu ERROR: .5+%g*/\n",
-         minmult, minadd, minshift, target, source, minerr-.5);
-
-   else if (print)
-      printf(
-         "number * %lu/%lu ~= (number * %lu + %ld) >> %lu +/-.5+%g [delta %ld]\n",
-         target, source, minmult, minadd, minshift, minerr-.5, mindelta);
-
-   return 0;
-}
-
-static void
-usage(const char *prog)
-{
-   fprintf(stderr,
-      "usage: %s {--denominator|--maxshift|--code} target {source}\n"
-      " For each 'source' prints 'mult' and 'add' such that:\n\n"
-      "   (number * mult + add) >> 16 = round(number*target/source)\n\n"
-      " for all integer values of number in the range 0..source.\n\n"
-      " --denominator: swap target and source (specify a single source first\n"
-      "                and follow with multiple targets.)\n"
-      "    --maxshift: find the lowest shift value that works for all the\n"
-      "                repeated 'source' values\n"
-      "        --code: output C code for array/structure initialization\n",
-      prog);
-   exit(1);
-}
-
-int
-main(int argc, const char **argv)
-{
-   int i, err = 0, maxshift = 0, firstsrc = 1, code = 0, denominator = 0;
-   unsigned long target, shift = 0;
-
-   while (argc > 1)
-   {
-      if (strcmp(argv[firstsrc], "--maxshift") == 0)
-      {
-         maxshift = 1;
-         ++firstsrc;
-      }
-
-      else if (strcmp(argv[firstsrc], "--code") == 0)
-      {
-         code = 1;
-         ++firstsrc;
-      }
-
-      else if (strcmp(argv[firstsrc], "--denominator") == 0)
-      {
-         denominator = 1;
-         ++firstsrc;
-      }
-
-      else
-         break;
-   }
-
-
-   if (argc < 2+firstsrc)
-      usage(argv[0]);
-
-   target = strtoul(argv[firstsrc++], 0, 0);
-   if (target == 0) usage(argv[0]);
-
-   for (i=firstsrc; i<argc; ++i)
-   {
-      unsigned long source = strtoul(argv[i], 0, 0);
-
-      if (source == 0) usage(argv[0]);
-
-      if (!find(denominator ? source : target, denominator ? target : source,
-         maxshift ? 0 : 1+code, -1))
-         err = 1;
-
-      if (minshift > shift) shift = minshift;
-   }
-
-   if (maxshift) for (i=firstsrc; i<argc; ++i)
-   {
-      unsigned long source = strtoul(argv[i], 0, 0);
-
-      if (!find(denominator ? source : target, denominator ? target : source,
-         code ? 4 : 1, shift))
-         err = 1;
-   }
-
-   /* Just an exit code - the printout above lists the problem */
-   return err;
-}
--- a/example.c
+++ b/example.c
@@ -2,8 +2,8 @@
 #if 0 /* in case someone actually tries to compile this */

 /* example.c - an example of using libpng
- * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- * Maintained 1998-2015 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.11 [June 5, 2014]
+ * Maintained 1998-2014 Glenn Randers-Pehrson
 * Maintained 1996, 1997 Andreas Dilger)
 * Written 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 * To the extent possible under law, the authors have waived
@@ -39,7 +39,7 @@
 #include <string.h>
 #include <stdio.h>
 #include <png.h>
-#include PNG_ZLIB_HEADER /* this is the header libpng was built with */
+#include <zlib.h>

 int main(int argc, const char **argv)
 {
@@ -52,7 +52,7 @@ int main(int argc, const char **argv)
      image.version = PNG_IMAGE_VERSION;

      /* The first argument is the file to read: */
-      if (png_image_begin_read_from_file(&image, argv[1]) != 0)
+      if (png_image_begin_read_from_file(&image, argv[1]))
      {
         png_bytep buffer;

@@ -97,7 +97,7 @@ int main(int argc, const char **argv)
          */
         if (buffer != NULL &&
            png_image_finish_read(&image, NULL/*background*/, buffer,
-               0/*row_stride*/, NULL/*colormap*/) != 0)
+               0/*row_stride*/, NULL/*colormap*/))
         {
            /* Now write the image out to the second argument.  In the write
             * call 'convert_to_8bit' allows 16-bit data to be squashed down to
@@ -105,7 +105,7 @@ int main(int argc, const char **argv)
             * to the 8-bit format.
             */
            if (png_image_write_to_file(&image, argv[2], 0/*convert_to_8bit*/,
-               buffer, 0/*row_stride*/, NULL/*colormap*/) != 0)
+               buffer, 0/*row_stride*/, NULL/*colormap*/))
            {
               /* The image has been written successfully. */
               exit(0);
@@ -188,13 +188,13 @@ int main(int argc, const char **argv)
 *
 * Don't repeatedly convert between the 8-bit and 16-bit forms.  There is
 * significant data loss when 16-bit data is converted to the 8-bit encoding and
- * the current libpng implementation of conversion to 16-bit is also
+ * the current libpng implementation of convertion to 16-bit is also
 * significantly lossy.  The latter will be fixed in the future, but the former
 * is unavoidable - the 8-bit format just doesn't have enough resolution.
 */

 /* If your program needs more information from the PNG data it reads, or if you
- * need to do more complex transformations, or minimize transformations, on the
+ * need to do more complex transformations, or minimise transformations, on the
 * data you read, then you must use one of the several lower level libpng
 * interfaces.
 *
@@ -405,7 +405,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
   /* Expand paletted or RGB images with transparency to full alpha channels
    * so the data will be available as RGBA quartets.
    */
-   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS) != 0)
+   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
      png_set_tRNS_to_alpha(png_ptr);

   /* Set the background color to draw transparent and alpha images over.
@@ -417,7 +417,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */

   png_color_16 my_background, *image_background;

-   if (png_get_bKGD(png_ptr, info_ptr, &image_background) != 0)
+   if (png_get_bKGD(png_ptr, info_ptr, &image_background))
      png_set_background(png_ptr, image_background,
                         PNG_BACKGROUND_GAMMA_FILE, 1, 1.0);
   else
@@ -454,12 +454,12 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */

   int intent;

-   if (png_get_sRGB(png_ptr, info_ptr, &intent) != 0)
+   if (png_get_sRGB(png_ptr, info_ptr, &intent))
      png_set_gamma(png_ptr, screen_gamma, PNG_DEFAULT_sRGB);
   else
   {
      double image_gamma;
-      if (png_get_gAMA(png_ptr, info_ptr, &image_gamma) != 0)
+      if (png_get_gAMA(png_ptr, info_ptr, &image_gamma))
         png_set_gamma(png_ptr, screen_gamma, image_gamma);
      else
         png_set_gamma(png_ptr, screen_gamma, 0.45455);
@@ -469,7 +469,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
   /* Quantize RGB files down to 8 bit palette or reduce palettes
    * to the number of colors available on your screen.
    */
-   if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
+   if (color_type & PNG_COLOR_MASK_COLOR)
   {
      int num_palette;
      png_colorp palette;
@@ -484,7 +484,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
            MAX_SCREEN_COLORS, NULL, 0);
      }
      /* This reduces the image to the palette supplied in the file */
-      else if (png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette) != 0)
+      else if (png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette))
      {
         png_uint_16p histogram = NULL;

@@ -494,7 +494,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
                        max_screen_colors, histogram, 0);
      }
   }
-#endif /* READ_QUANTIZE */
+#endif /* PNG_READ_QUANTIZE_SUPPORTED */

   /* Invert monochrome files to have 0 as white and 1 as black */
   png_set_invert_mono(png_ptr);
@@ -503,7 +503,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
    * [0,65535] to the original [0,7] or [0,31], or whatever range the
    * colors were originally in:
    */
-   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT) != 0)
+   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT))
   {
      png_color_8p sig_bit_p;

@@ -512,7 +512,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
   }

   /* Flip the RGB pixels to BGR (or RGBA to BGRA) */
-   if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
+   if (color_type & PNG_COLOR_MASK_COLOR)
      png_set_bgr(png_ptr);

   /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */
@@ -532,7 +532,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
   number_passes = png_set_interlace_handling(png_ptr);
 #else
   number_passes = 1;
-#endif /* READ_INTERLACING */
+#endif /* PNG_READ_INTERLACING_SUPPORTED */


   /* Optional call to gamma correct and add the background to the palette
@@ -744,7 +744,7 @@ row_callback(png_structp png_ptr, png_bytep new_row,
    * to pass the current row as new_row, and the function will combine
    * the old row and the new row.
    */
-#endif /* READ_INTERLACING */
+#endif /* PNG_READ_INTERLACING_SUPPORTED */
 }

 end_callback(png_structp png_ptr, png_infop info)
@@ -932,7 +932,7 @@ void write_png(char *file_name /* , ... other image information ... */)
    */

   /* Once we write out the header, the compression type on the text
-    * chunk gets changed to PNG_TEXT_COMPRESSION_NONE_WR or
+    * chunks gets changed to PNG_TEXT_COMPRESSION_NONE_WR or
    * PNG_TEXT_COMPRESSION_zTXt_WR, so it doesn't get written out again
    * at the end.
    */
--- a/libpng-manual.txt
+++ b/libpng-manual.txt
@@ -1,9 +1,9 @@
 libpng-manual.txt - A description on how to use and modify libpng

- libpng version 1.7.0beta52 - February 21, 2015
+ libpng version 1.6.13beta04 - August 8, 2014
 Updated and distributed by Glenn Randers-Pehrson
 <glennrp at users.sourceforge.net>
- Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ Copyright (c) 1998-2014 Glenn Randers-Pehrson

 This document is released under the libpng license.
 For conditions of distribution and use, see the disclaimer
@@ -11,15 +11,15 @@ libpng-manual.txt - A description on how to use and modify libpng

 Based on:

- libpng versions 0.97, January 1998, through 1.7.0beta52 - February 21, 2015
+ libpng versions 0.97, January 1998, through 1.6.13beta04 - August 8, 2014
 Updated and distributed by Glenn Randers-Pehrson
- Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ Copyright (c) 1998-2014 Glenn Randers-Pehrson

- libpng 1.0 beta 6  version 0.96 May 28, 1997
+ libpng 1.0 beta 6 - version 0.96 - May 28, 1997
 Updated and distributed by Andreas Dilger
 Copyright (c) 1996, 1997 Andreas Dilger

- libpng 1.0 beta 2 - version 0.88  January 26, 1996
+ libpng 1.0 beta 2 - version 0.88 - January 26, 1996
 For conditions of distribution and use, see copyright
 notice in png.h. Copyright (c) 1995, 1996 Guy Eric
 Schalnat, Group 42, Inc.
@@ -42,11 +42,10 @@ libpng-manual.txt - A description on how to use and modify libpng
    X. Changes to Libpng from version 1.0.x/1.2.x to 1.4.x
   XI. Changes to Libpng from version 1.4.x to 1.5.x
  XII. Changes to Libpng from version 1.5.x to 1.6.x
- XIII. Changes to Libpng from version 1.6.x to 1.7.x
-  XIV. Detecting libpng
-   XV. Source code repository
-  XVI. Coding style
- XVII. Y2K Compliance in libpng
+ XIII. Detecting libpng
+  XIV. Source code repository
+   XV. Coding style
+  XVI. Y2K Compliance in libpng

 I. Introduction

@@ -428,16 +427,12 @@ an end_info structure.

 If you would rather avoid the complexity of setjmp/longjmp issues,
 you can compile libpng with PNG_NO_SETJMP, in which case
-errors will result in a call to PNG_ABORT which defaults to abort().
+errors will result in a call to PNG_ABORT() which defaults to abort().

-You can #define PNG_ABORT to a function or other C code that does something
+You can #define PNG_ABORT() to a function that does something
 more useful than abort(), as long as your function does not
 return.

-If you do this, you cannot #define PNG_SIMPLIFIED_READ_SUPPORTED or
-PNG_SIMPLIFIED_WRITE_SUPPORTED, because the simplified API requires
-setjmp() support.
-
 Now you need to set up the input code.  The default for libpng is to
 use the C function fread().  If you use this, you will need to pass a
 valid FILE * in the function png_init_io().  Be sure that the file is
@@ -529,15 +524,15 @@ you can retrieve with

    png_get_user_chunk_ptr(png_ptr);

-If you call the png_set_read_user_chunk_fn() function, then all unknown chunks
-will be passed to your callback when read.  You can cause known chunks to be
-passed in as well by using png_set_keep_unknown_chunks (see below) - this will
-prevent the normal libpng handling of those known chunks.
-
-If your callback returns 0 the default unknown handling will be used (see
-below).  This is new behavior in libpng 1.7, prior to 1.7 it was not possible to
-discard a chunk; PNG_HANDLE_CHUNK_IF_SAFE was forced.  Libpng 1.6.0 issues a
-warning when this was done.
+If you call the png_set_read_user_chunk_fn() function, then all unknown
+chunks which the callback does not handle will be saved when read.  You can
+cause them to be discarded by returning '1' ("handled") instead of '0'.  This
+behavior will change in libpng 1.7 and the default handling set by the
+png_set_keep_unknown_chunks() function, described below, will be used when the
+callback returns 0.  If you want the existing behavior you should set the global
+default to PNG_HANDLE_CHUNK_IF_SAFE now; this is compatible with all current
+versions of libpng and with 1.7.  Libpng 1.6 issues a warning if you keep the
+default, or PNG_HANDLE_CHUNK_NEVER, and the callback returns 0.

 At this point, you can set up a callback function that will be
 called after each row has been read, which you can use to control
@@ -636,8 +631,10 @@ callback function:
    ...

    #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
-      /* ignore all unknown chunks: */
-      png_set_keep_unknown_chunks(read_ptr, 1, NULL, 0);
+      /* ignore all unknown chunks
+       * (use global setting "2" for libpng16 and earlier):
+       */
+      png_set_keep_unknown_chunks(read_ptr, 2, NULL, 0);

      /* except for vpAg: */
      png_set_keep_unknown_chunks(read_ptr, 2, vpAg, 1);
@@ -652,7 +649,7 @@ User limits
 The PNG specification allows the width and height of an image to be as
 large as 2^31-1 (0x7fffffff), or about 2.147 billion rows and columns.
 Since very few applications really need to process such large images,
-we have imposed an arbitrary 1,000,000 limit on rows and columns.
+we have imposed an arbitrary 1-million limit on rows and columns.
 Larger images will be rejected immediately with a png_error() call. If
 you wish to change this limit, you can use

@@ -1185,10 +1182,7 @@ row_pointers prior to calling png_read_png() with
   png_set_rows(png_ptr, info_ptr, &row_pointers);

 Alternatively you could allocate your image in one big block and define
-row_pointers[i] to point into the proper places in your block.  If
-you do this, be sure to call png_read_update_info() described below,
-to update the "rowbytes" value to account for any transformations that
-change the number of bytes per row before you use it to allocate your block.
+row_pointers[i] to point into the proper places in your block.

 If you use png_set_rows(), the application is responsible for freeing
 row_pointers (and row_pointers[i], if they were separately allocated).
@@ -1273,17 +1267,16 @@ in until png_read_end() has read the chunk data following the image.
                     the PNG datastream is embedded in
                     a MNG-1.0 datastream)

-    Any of width, height, color_type, bit_depth,
-    interlace_type, compression_type, or filter_method can
-    be NULL if you are not interested in their values.
+    Any or all of interlace_type, compression_type, or
+    filter_method can be NULL if you are
+    not interested in their values.

-    Note that png_get_IHDR() returns png_uint_32 data into
+    Note that png_get_IHDR() returns 32-bit data into
    the application's width and height variables.
-    This is an unsafe situation if these are not png_uint_32
-    variables, or if they are 32-bit variables on a 64-bit
-    platform.  In such situations, the png_get_image_width()
-    and png_get_image_height() functions described below are
-    safer.
+    This is an unsafe situation if these are 16-bit
+    variables.  In such situations, the
+    png_get_image_width() and png_get_image_height()
+    functions described below are safer.

    width            = png_get_image_width(png_ptr,
                         info_ptr);
@@ -2746,10 +2739,11 @@ section below for more information on the libpng error handling.

 If you would rather avoid the complexity of setjmp/longjmp issues,
 you can compile libpng with PNG_NO_SETJMP, in which case
-errors will result in a call to PNG_ABORT which defaults to abort().
+errors will result in a call to PNG_ABORT() which defaults to abort().

-You can #define PNG_ABORT to a function or other C code that does something
-more useful than abort(), as long as your function does not return.
+You can #define PNG_ABORT() to a function that does something
+more useful than abort(), as long as your function does not
+return.

 Checking for invalid palette index on write was added at libpng
 1.5.10.  If a pixel contains an invalid (out-of-range) index libpng issues
@@ -4167,7 +4161,7 @@ Error handling in libpng is done through png_error() and png_warning().
 Errors handled through png_error() are fatal, meaning that png_error()
 should never return to its caller.  Currently, this is handled via
 setjmp() and longjmp() (unless you have compiled libpng with
-PNG_NO_SETJMP, in which case it is handled via PNG_ABORT),
+PNG_NO_SETJMP, in which case it is handled via PNG_ABORT()),
 but you could change this to do things like exit() if you should wish,
 as long as your function does not return.

@@ -5043,8 +5037,8 @@ where "rp" indicates a "restricted pointer".
 Error detection in some chunks has improved; in particular the iCCP chunk
 reader now does pretty complete validation of the basic format.  Some bad
 profiles that were previously accepted are now accepted with a warning or
-rejected, depending upon the png_set_benign_errors() setting, in particular
-the very old broken Microsoft/HP 3144-byte sRGB profile.  Starting with
+rejected, depending upon the png_set_benign_errors() setting, in particular the
+very old broken Microsoft/HP 3144-byte sRGB profile.  Starting with
 libpng-1.6.11, recognizing and checking sRGB profiles can be avoided by
 means of

@@ -5055,7 +5049,7 @@ means of
    #endif

 It's not a good idea to do this if you are using the "simplified API",
-which needs to be able to recognize sRGB profiles conveyed via the iCCP
+which needs to be able to recognize an sRGB profile conveyed via the iCCP
 chunk.

 The PNG spec requirement that only grayscale profiles may appear in images
@@ -5065,7 +5059,6 @@ enforced.  The sRGB chunk is allowed to appear in images with any color type
 and is interpreted by libpng to convey a one-tracer-curve gray profile or a
 three-tracer-curve RGB profile as appropriate.

-
 Prior to libpng-1.6.0 a warning would be issued if the iTXt chunk contained
 an empty language field or an empty translated keyword.  Both of these
 are allowed by the PNG specification, so these warnings are no longer issued.
@@ -5114,55 +5107,7 @@ length, which resulted in PNG files that cannot be read beyond the bad iTXt
 chunk.  This error was fixed in libpng-1.6.3, and a tool (called
 contrib/tools/png-fix-itxt) has been added to the libpng distribution.

-Starting with libpng-1.6.17, the PNG_SAFE_LIMITS macro was eliminated
-and safe limits are used by default (users who need larger limits
-can still override them at compile time or run time, as described above).
-
-The new limits are
-                                default   spec limit
-   png_user_width_max         1,000,000  2,147,483,647
-   png_user_height_max        1,000,000  2,147,483,647
-   png_user_chunk_cache_max         128  unlimited
-   png_user_chunk_malloc_max  8,000,000  unlimited
-
-XIII.  Changes to Libpng from version 1.6.x to 1.7.x
-
-Some functions that were deprecated in libpng-1.6.0 were removed:
-    png_reset_zstream(),
-    png_info_init_3(),
-    png_data_freer() and its associated flags,
-    png_malloc_default(),
-    and png_free_default().
-
-The PNG_ABORT() macro was changed to PNG_ABORT, and the default is now
-"abort()" for all platforms (previously it was "ExitProcess(0)" on
-Windows platforms).  Starting with libpng-1.7.0 you have to define
-PNG_ABORT instead of PNG_ABORT(), and you must include a terminating
-semicolon in your definition, e.g.,
-
-    #if PNGCRUSH_LIBPNG_VER >= 10700
-    #  ifdef _WINDOWS_
-    #    define PNG_ABORT ExitProcess(0);
-    #  else
-    #    define PNG_ABORT abort();
-    #  endif
-    #else
-    #  ifdef _WINDOWS_
-    #    define PNG_ABORT() ExitProcess(0)
-    #  else
-    #    define PNG_ABORT() abort()
-    #  endif
-    #endif
-
-The png_get_IHDR() function now allows users to supply NULL for any
-argument in which they aren't interested.  Previously, the width, height,
-bit_depth, and color_type arguments were not allowed to be NULL.
-
-The 8-bit compose and rgb_to_grayscale operations were made more accurate.
-While these did not introduce API incompatibility, there may be differences
-in unit test results.
-
-XIV.  Detecting libpng
+XIII.  Detecting libpng

 The png_get_io_ptr() function has been present since libpng-0.88, has never
 changed, and is unaffected by conditional compilation macros.  It is the
@@ -5195,7 +5140,7 @@ simple verbal discriptions of bug fixes, reported either to the
 SourceForge bug tracker, to the png-mng-implement at lists.sf.net
 mailing list, or directly to glennrp.

-XVI. Coding style
+XV. Coding style

 Our coding style is similar to the "Allman" style
 (See http://en.wikipedia.org/wiki/Indent_style#Allman_style), with curly
@@ -5278,15 +5223,12 @@ We mark all non-exported functions with "/* PRIVATE */"":
 }

 The prototypes for non-exported functions (except for those in
-pngtest) appear in pngpriv.h above the comment that says
+pngtest) appear in
+pngpriv.h
+above the comment that says

  /* Maintainer: Put new private prototypes here ^ */

-To avoid polluting the global namespace, the names of all exported
-functions and variables begin with "png_", and all publicly visible C
-preprocessor macros begin with "PNG".  We request that applications that
-use libpng *not* begin any of their own symbols with either of these strings.
-
 We put a space after the "sizeof" operator and we omit the
 optional parentheses around its argument when the argument
 is an expression, not a type name, and we always enclose the
@@ -5298,8 +5240,10 @@ sizeof operator, with its argument, in parentheses:
 Prior to libpng-1.6.0 we used a "png_sizeof()" macro, formatted as
 though it were a function.

-Control keywords if, for, while, and switch are always followed by a space
-to distinguish them from function calls, which have no trailing space. 
+To avoid polluting the global namespace, the names of all exported
+functions and variables begin with "png_", and all publicly visible C
+preprocessor macros begin with "PNG".  We request that applications that
+use libpng *not* begin any of their own symbols with either of these strings.

 We put a space after each comma and after each semicolon
 in "for" statements, and we put spaces before and after each
@@ -5330,15 +5274,15 @@ Lines do not exceed 80 characters.

 Other rules can be inferred by inspecting the libpng source.

-XVII. Y2K Compliance in libpng
+XVI. Y2K Compliance in libpng

-February 21, 2015
+August 8, 2014

 Since the PNG Development group is an ad-hoc body, we can't make
 an official declaration.

 This is your unofficial assurance that libpng from version 0.71 and
-upward through 1.7.0beta52 are Y2K compliant.  It is my belief that earlier
+upward through 1.6.13beta04 are Y2K compliant.  It is my belief that earlier
 versions were also Y2K compliant.

 Libpng only has two year fields.  One is a 2-byte unsigned integer
--- a/libpng.3
+++ b/libpng.3
@@ -1,6 +1,6 @@
-.TH LIBPNG 3 "February 21, 2015"
+.TH LIBPNG 3 "August 8, 2014"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.7.0beta52
+libpng \- Portable Network Graphics (PNG) Reference Library 1.6.13beta04
 .SH SYNOPSIS
 \fB
 #include <png.h>\fP
@@ -23,7 +23,7 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.7.0beta52

 \fBvoid png_convert_from_time_t (png_timep \fP\fIptime\fP\fB, time_t \fIttime\fP\fB);\fP

-\fBpng_charp png_convert_to_rfc1123_buffer (png_structp \fP\fIpng_ptr\fP\fB, char \fP\fIout[29]\fP\fB, png_timep \fIptime\fP\fB);\fP
+\fBpng_charp png_convert_to_rfc1123 (png_structp \fP\fIpng_ptr\fP\fB, png_timep \fIptime\fP\fB);\fP

 \fBpng_infop png_create_info_struct (png_structp \fIpng_ptr\fP\fB);\fP

@@ -35,6 +35,8 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.7.0beta52

 \fBpng_structp png_create_write_struct_2 (png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fP\fIwarn_fn\fP\fB, png_voidp \fP\fImem_ptr\fP\fB, png_malloc_ptr \fP\fImalloc_fn\fP\fB, png_free_ptr \fIfree_fn\fP\fB);\fP

+\fBvoid png_data_freer (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIfreer\fP\fB, png_uint_32 \fImask)\fP\fB);\fP
+
 \fBvoid png_destroy_info_struct (png_structp \fP\fIpng_ptr\fP\fB, png_infopp \fIinfo_ptr_ptr\fP\fB);\fP

 \fBvoid png_destroy_read_struct (png_structpp \fP\fIpng_ptr_ptr\fP\fB, png_infopp \fP\fIinfo_ptr_ptr\fP\fB, png_infopp \fIend_info_ptr_ptr\fP\fB);\fP
@@ -49,6 +51,8 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.7.0beta52

 \fBvoid png_free_chunk_list (png_structp \fIpng_ptr\fP\fB);\fP

+\fBvoid png_free_default (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fIptr\fP\fB);\fP
+
 \fBvoid png_free_data (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fInum\fP\fB);\fP

 \fBpng_byte png_get_bit_depth (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
@@ -225,12 +229,16 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.7.0beta52

 \fBint png_image_write_to_stdio (png_imagep \fP\fIimage\fP\fB, FILE \fP\fI*file\fP\fB, int \fP\fIconvert_to_8_bit\fP\fB, const void \fP\fI*buffer\fP\fB, png_int_32 \fP\fIrow_stride\fP\fB, void \fI*colormap)\fP\fB);\fP

+\fBvoid png_info_init_3 (png_infopp \fP\fIinfo_ptr\fP\fB, png_size_t \fIpng_info_struct_size\fP\fB);\fP
+
 \fBvoid png_init_io (png_structp \fP\fIpng_ptr\fP\fB, FILE \fI*fp\fP\fB);\fP

 \fBvoid png_longjmp (png_structp \fP\fIpng_ptr\fP\fB, int \fIval\fP\fB);\fP

 \fBpng_voidp png_malloc (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP

+\fBpng_voidp png_malloc_default (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP
+
 \fBpng_voidp png_malloc_warn (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP

 \fBpng_uint_32 png_permit_mng_features (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fImng_features_permitted\fP\fB);\fP
@@ -257,6 +265,8 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.7.0beta52

 \fBvoid png_read_update_info (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP

+\fBint png_reset_zstream (png_structp \fIpng_ptr\fP\fB);\fP
+
 \fBvoid png_save_int_32 (png_bytep \fP\fIbuf\fP\fB, png_int_32 \fIi\fP\fB);\fP

 \fBvoid png_save_uint_16 (png_bytep \fP\fIbuf\fP\fB, unsigned int \fIi\fP\fB);\fP
@@ -494,10 +504,10 @@ Following is a copy of the libpng-manual.txt file that accompanies libpng.
 .SH LIBPNG.TXT
 libpng-manual.txt - A description on how to use and modify libpng

- libpng version 1.7.0beta52 - February 21, 2015
+ libpng version 1.6.13beta04 - August 8, 2014
 Updated and distributed by Glenn Randers-Pehrson
 <glennrp at users.sourceforge.net>
- Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ Copyright (c) 1998-2014 Glenn Randers-Pehrson

 This document is released under the libpng license.
 For conditions of distribution and use, see the disclaimer
@@ -505,15 +515,15 @@ libpng-manual.txt - A description on how to use and modify libpng

 Based on:

- libpng versions 0.97, January 1998, through 1.7.0beta52 - February 21, 2015
+ libpng versions 0.97, January 1998, through 1.6.13beta04 - August 8, 2014
 Updated and distributed by Glenn Randers-Pehrson
- Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ Copyright (c) 1998-2014 Glenn Randers-Pehrson

- libpng 1.0 beta 6  version 0.96 May 28, 1997
+ libpng 1.0 beta 6 - version 0.96 - May 28, 1997
 Updated and distributed by Andreas Dilger
 Copyright (c) 1996, 1997 Andreas Dilger

- libpng 1.0 beta 2 - version 0.88  January 26, 1996
+ libpng 1.0 beta 2 - version 0.88 - January 26, 1996
 For conditions of distribution and use, see copyright
 notice in png.h. Copyright (c) 1995, 1996 Guy Eric
 Schalnat, Group 42, Inc.
@@ -536,11 +546,10 @@ libpng-manual.txt - A description on how to use and modify libpng
    X. Changes to Libpng from version 1.0.x/1.2.x to 1.4.x
   XI. Changes to Libpng from version 1.4.x to 1.5.x
  XII. Changes to Libpng from version 1.5.x to 1.6.x
- XIII. Changes to Libpng from version 1.6.x to 1.7.x
-  XIV. Detecting libpng
-   XV. Source code repository
-  XVI. Coding style
- XVII. Y2K Compliance in libpng
+ XIII. Detecting libpng
+  XIV. Source code repository
+   XV. Coding style
+  XVI. Y2K Compliance in libpng

 .SH I. Introduction

@@ -922,16 +931,12 @@ an end_info structure.

 If you would rather avoid the complexity of setjmp/longjmp issues,
 you can compile libpng with PNG_NO_SETJMP, in which case
-errors will result in a call to PNG_ABORT which defaults to abort().
+errors will result in a call to PNG_ABORT() which defaults to abort().

-You can #define PNG_ABORT to a function or other C code that does something
+You can #define PNG_ABORT() to a function that does something
 more useful than abort(), as long as your function does not
 return.

-If you do this, you cannot #define PNG_SIMPLIFIED_READ_SUPPORTED or
-PNG_SIMPLIFIED_WRITE_SUPPORTED, because the simplified API requires
-setjmp() support.
-
 Now you need to set up the input code.  The default for libpng is to
 use the C function fread().  If you use this, you will need to pass a
 valid FILE * in the function png_init_io().  Be sure that the file is
@@ -1023,15 +1028,15 @@ you can retrieve with

    png_get_user_chunk_ptr(png_ptr);

-If you call the png_set_read_user_chunk_fn() function, then all unknown chunks
-will be passed to your callback when read.  You can cause known chunks to be
-passed in as well by using png_set_keep_unknown_chunks (see below) - this will
-prevent the normal libpng handling of those known chunks.
-
-If your callback returns 0 the default unknown handling will be used (see
-below).  This is new behavior in libpng 1.7, prior to 1.7 it was not possible to
-discard a chunk; PNG_HANDLE_CHUNK_IF_SAFE was forced.  Libpng 1.6.0 issues a
-warning when this was done.
+If you call the png_set_read_user_chunk_fn() function, then all unknown
+chunks which the callback does not handle will be saved when read.  You can
+cause them to be discarded by returning '1' ("handled") instead of '0'.  This
+behavior will change in libpng 1.7 and the default handling set by the
+png_set_keep_unknown_chunks() function, described below, will be used when the
+callback returns 0.  If you want the existing behavior you should set the global
+default to PNG_HANDLE_CHUNK_IF_SAFE now; this is compatible with all current
+versions of libpng and with 1.7.  Libpng 1.6 issues a warning if you keep the
+default, or PNG_HANDLE_CHUNK_NEVER, and the callback returns 0.

 At this point, you can set up a callback function that will be
 called after each row has been read, which you can use to control
@@ -1130,8 +1135,10 @@ callback function:
    ...

    #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
-      /* ignore all unknown chunks: */
-      png_set_keep_unknown_chunks(read_ptr, 1, NULL, 0);
+      /* ignore all unknown chunks
+       * (use global setting "2" for libpng16 and earlier):
+       */
+      png_set_keep_unknown_chunks(read_ptr, 2, NULL, 0);

      /* except for vpAg: */
      png_set_keep_unknown_chunks(read_ptr, 2, vpAg, 1);
@@ -1146,7 +1153,7 @@ callback function:
 The PNG specification allows the width and height of an image to be as
 large as 2^(31\-1 (0x7fffffff), or about 2.147 billion rows and columns.
 Since very few applications really need to process such large images,
-we have imposed an arbitrary 1,000,000 limit on rows and columns.
+we have imposed an arbitrary 1-million limit on rows and columns.
 Larger images will be rejected immediately with a png_error() call. If
 you wish to change this limit, you can use

@@ -1679,10 +1686,7 @@ row_pointers prior to calling png_read_png() with
   png_set_rows(png_ptr, info_ptr, &row_pointers);

 Alternatively you could allocate your image in one big block and define
-row_pointers[i] to point into the proper places in your block.  If
-you do this, be sure to call png_read_update_info() described below,
-to update the "rowbytes" value to account for any transformations that
-change the number of bytes per row before you use it to allocate your block.
+row_pointers[i] to point into the proper places in your block.

 If you use png_set_rows(), the application is responsible for freeing
 row_pointers (and row_pointers[i], if they were separately allocated).
@@ -1767,17 +1771,16 @@ in until png_read_end() has read the chunk data following the image.
                     the PNG datastream is embedded in
                     a MNG-1.0 datastream)

-    Any of width, height, color_type, bit_depth,
-    interlace_type, compression_type, or filter_method can
-    be NULL if you are not interested in their values.
+    Any or all of interlace_type, compression_type, or
+    filter_method can be NULL if you are
+    not interested in their values.

-    Note that png_get_IHDR() returns png_uint_32 data into
+    Note that png_get_IHDR() returns 32-bit data into
    the application's width and height variables.
-    This is an unsafe situation if these are not png_uint_32
-    variables, or if they are 32-bit variables on a 64-bit
-    platform.  In such situations, the png_get_image_width()
-    and png_get_image_height() functions described below are
-    safer.
+    This is an unsafe situation if these are 16-bit
+    variables.  In such situations, the
+    png_get_image_width() and png_get_image_height()
+    functions described below are safer.

    width            = png_get_image_width(png_ptr,
                         info_ptr);
@@ -3240,10 +3243,11 @@ section below for more information on the libpng error handling.

 If you would rather avoid the complexity of setjmp/longjmp issues,
 you can compile libpng with PNG_NO_SETJMP, in which case
-errors will result in a call to PNG_ABORT which defaults to abort().
+errors will result in a call to PNG_ABORT() which defaults to abort().

-You can #define PNG_ABORT to a function or other C code that does something
-more useful than abort(), as long as your function does not return.
+You can #define PNG_ABORT() to a function that does something
+more useful than abort(), as long as your function does not
+return.

 Checking for invalid palette index on write was added at libpng
 1.5.10.  If a pixel contains an invalid (out-of-range) index libpng issues
@@ -4661,7 +4665,7 @@ Error handling in libpng is done through png_error() and png_warning().
 Errors handled through png_error() are fatal, meaning that png_error()
 should never return to its caller.  Currently, this is handled via
 setjmp() and longjmp() (unless you have compiled libpng with
-PNG_NO_SETJMP, in which case it is handled via PNG_ABORT),
+PNG_NO_SETJMP, in which case it is handled via PNG_ABORT()),
 but you could change this to do things like exit() if you should wish,
 as long as your function does not return.

@@ -5537,8 +5541,8 @@ where "rp" indicates a "restricted pointer".
 Error detection in some chunks has improved; in particular the iCCP chunk
 reader now does pretty complete validation of the basic format.  Some bad
 profiles that were previously accepted are now accepted with a warning or
-rejected, depending upon the png_set_benign_errors() setting, in particular
-the very old broken Microsoft/HP 3144-byte sRGB profile.  Starting with
+rejected, depending upon the png_set_benign_errors() setting, in particular the
+very old broken Microsoft/HP 3144-byte sRGB profile.  Starting with
 libpng-1.6.11, recognizing and checking sRGB profiles can be avoided by
 means of

@@ -5549,7 +5553,7 @@ means of
    #endif

 It's not a good idea to do this if you are using the "simplified API",
-which needs to be able to recognize sRGB profiles conveyed via the iCCP
+which needs to be able to recognize an sRGB profile conveyed via the iCCP
 chunk.

 The PNG spec requirement that only grayscale profiles may appear in images
@@ -5559,7 +5563,6 @@ enforced.  The sRGB chunk is allowed to appear in images with any color type
 and is interpreted by libpng to convey a one-tracer-curve gray profile or a
 three-tracer-curve RGB profile as appropriate.

-
 Prior to libpng-1.6.0 a warning would be issued if the iTXt chunk contained
 an empty language field or an empty translated keyword.  Both of these
 are allowed by the PNG specification, so these warnings are no longer issued.
@@ -5608,55 +5611,7 @@ length, which resulted in PNG files that cannot be read beyond the bad iTXt
 chunk.  This error was fixed in libpng-1.6.3, and a tool (called
 contrib/tools/png-fix-itxt) has been added to the libpng distribution.

-Starting with libpng-1.6.17, the PNG_SAFE_LIMITS macro was eliminated
-and safe limits are used by default (users who need larger limits
-can still override them at compile time or run time, as described above).
-
-The new limits are
-                                default   spec limit
-   png_user_width_max         1,000,000  2,147,483,647
-   png_user_height_max        1,000,000  2,147,483,647
-   png_user_chunk_cache_max         128  unlimited
-   png_user_chunk_malloc_max  8,000,000  unlimited
-
-.SH XIII.  Changes to Libpng from version 1.6.x to 1.7.x
-
-Some functions that were deprecated in libpng-1.6.0 were removed:
-    png_reset_zstream(),
-    png_info_init_3(),
-    png_data_freer() and its associated flags,
-    png_malloc_default(),
-    and png_free_default().
-
-The PNG_ABORT() macro was changed to PNG_ABORT, and the default is now
-"abort()" for all platforms (previously it was "ExitProcess(0)" on
-Windows platforms).  Starting with libpng-1.7.0 you have to define
-PNG_ABORT instead of PNG_ABORT(), and you must include a terminating
-semicolon in your definition, e.g.,
-
-    #if PNGCRUSH_LIBPNG_VER >= 10700
-    #  ifdef _WINDOWS_
-    #    define PNG_ABORT ExitProcess(0);
-    #  else
-    #    define PNG_ABORT abort();
-    #  endif
-    #else
-    #  ifdef _WINDOWS_
-    #    define PNG_ABORT() ExitProcess(0)
-    #  else
-    #    define PNG_ABORT() abort()
-    #  endif
-    #endif
-
-The png_get_IHDR() function now allows users to supply NULL for any
-argument in which they aren't interested.  Previously, the width, height,
-bit_depth, and color_type arguments were not allowed to be NULL.
-
-The 8-bit compose and rgb_to_grayscale operations were made more accurate.
-While these did not introduce API incompatibility, there may be differences
-in unit test results.
-
-.SH XIV.  Detecting libpng
+.SH XIII.  Detecting libpng

 The png_get_io_ptr() function has been present since libpng-0.88, has never
 changed, and is unaffected by conditional compilation macros.  It is the
@@ -5689,7 +5644,7 @@ simple verbal discriptions of bug fixes, reported either to the
 SourceForge bug tracker, to the png-mng-implement at lists.sf.net
 mailing list, or directly to glennrp.

-.SH XVI. Coding style
+.SH XV. Coding style

 Our coding style is similar to the "Allman" style
 (See http://en.wikipedia.org/wiki/Indent_style#Allman_style), with curly
@@ -5772,15 +5727,12 @@ We mark all non-exported functions with "/* PRIVATE */"":
 }

 The prototypes for non-exported functions (except for those in
-pngtest) appear in pngpriv.h above the comment that says
+pngtest) appear in
+pngpriv.h
+above the comment that says

  /* Maintainer: Put new private prototypes here ^ */

-To avoid polluting the global namespace, the names of all exported
-functions and variables begin with "png_", and all publicly visible C
-preprocessor macros begin with "PNG".  We request that applications that
-use libpng *not* begin any of their own symbols with either of these strings.
-
 We put a space after the "sizeof" operator and we omit the
 optional parentheses around its argument when the argument
 is an expression, not a type name, and we always enclose the
@@ -5792,8 +5744,10 @@ sizeof operator, with its argument, in parentheses:
 Prior to libpng-1.6.0 we used a "png_sizeof()" macro, formatted as
 though it were a function.

-Control keywords if, for, while, and switch are always followed by a space
-to distinguish them from function calls, which have no trailing space. 
+To avoid polluting the global namespace, the names of all exported
+functions and variables begin with "png_", and all publicly visible C
+preprocessor macros begin with "PNG".  We request that applications that
+use libpng *not* begin any of their own symbols with either of these strings.

 We put a space after each comma and after each semicolon
 in "for" statements, and we put spaces before and after each
@@ -5824,15 +5778,15 @@ Lines do not exceed 80 characters.

 Other rules can be inferred by inspecting the libpng source.

-.SH XVII. Y2K Compliance in libpng
+.SH XVI. Y2K Compliance in libpng

-February 21, 2015
+August 8, 2014

 Since the PNG Development group is an ad-hoc body, we can't make
 an official declaration.

 This is your unofficial assurance that libpng from version 0.71 and
-upward through 1.7.0beta52 are Y2K compliant.  It is my belief that earlier
+upward through 1.6.13beta04 are Y2K compliant.  It is my belief that earlier
 versions were also Y2K compliant.

 Libpng only has two year fields.  One is a 2-byte unsigned integer
@@ -6037,9 +5991,41 @@ the first widely used release:
 1.5.7beta01-05      15    10507  15.so.15.7[.0]
 1.5.7rc01-03        15    10507  15.so.15.7[.0]
 1.5.7               15    10507  15.so.15.7[.0]
- 1.6.0beta01-37      16    10600  16.so.16.0[.0]
- 1.7.0alpha01-10     17    10700  17.so.17.0[.0]
- 1.7.0beta01-52      17    10700  17.so.17.0[.0]
+ 1.6.0beta01-40      16    10600  16.so.16.0[.0]
+ 1.6.0rc01-08        16    10600  16.so.16.0[.0]
+ 1.6.0               16    10600  16.so.16.0[.0]
+ 1.6.1beta01-09      16    10601  16.so.16.1[.0]
+ 1.6.1rc01           16    10601  16.so.16.1[.0]
+ 1.6.1               16    10601  16.so.16.1[.0]
+ 1.6.2beta01         16    10602  16.so.16.2[.0]
+ 1.6.2rc01-06        16    10602  16.so.16.2[.0]
+ 1.6.2               16    10602  16.so.16.2[.0]
+ 1.6.3beta01-11      16    10603  16.so.16.3[.0]
+ 1.6.3rc01           16    10603  16.so.16.3[.0]
+ 1.6.3               16    10603  16.so.16.3[.0]
+ 1.6.4beta01-02      16    10604  16.so.16.4[.0]
+ 1.6.4rc01           16    10604  16.so.16.4[.0]
+ 1.6.4               16    10604  16.so.16.4[.0]
+ 1.6.5               16    10605  16.so.16.5[.0]
+ 1.6.6               16    10606  16.so.16.6[.0]
+ 1.6.7beta01-04      16    10607  16.so.16.7[.0]
+ 1.6.7rc01-02        16    10607  16.so.16.7[.0]
+ 1.6.7               16    10607  16.so.16.7[.0]
+ 1.6.8beta01-02      16    10608  16.so.16.8[.0]
+ 1.6.8rc01-02        16    10608  16.so.16.8[.0]
+ 1.6.8               16    10608  16.so.16.8[.0]
+ 1.6.9beta01-04      16    10609  16.so.16.9[.0]
+ 1.6.9rc01-02        16    10609  16.so.16.9[.0]
+ 1.6.9               16    10609  16.so.16.9[.0]
+ 1.6.10beta01-03     16    10610  16.so.16.10[.0]
+ 1.6.10rc01-03       16    10610  16.so.16.10[.0]
+ 1.6.10              16    10610  16.so.16.10[.0]
+ 1.6.11beta01-06     16    10611  16.so.16.11[.0]
+ 1.6.11rc01-02       16    10611  16.so.16.11[.0]
+ 1.6.11              16    10611  16.so.16.11[.0]
+ 1.6.12rc01          16    10612  16.so.16.12[.0]
+ 1.6.12              16    10612  16.so.16.12[.0]
+ 1.6.13beta01-04     16    10613  16.so.16.13[.0]

 Henceforth the source version will match the shared-library minor
 and patch numbers; the shared-library major version number will be
@@ -6096,7 +6082,7 @@ possible without all of you.

 Thanks to Frank J. T. Wojcik for helping with the documentation.

-Libpng version 1.7.0beta52 - February 21, 2015:
+Libpng version 1.6.13beta04 - August 8, 2014:
 Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc.
 Currently maintained by Glenn Randers-Pehrson (glennrp at users.sourceforge.net).

@@ -6119,8 +6105,8 @@ this sentence.

 This code is released under the libpng license.

-libpng versions 1.2.6, August 15, 2004, through 1.7.0beta52, February 21, 2015, are
-Copyright (c) 2004,2006-2007 Glenn Randers-Pehrson, and are
+libpng versions 1.2.6, August 15, 2004, through 1.6.13beta04, August 8, 2014, are
+Copyright (c) 2004,2006-2014 Glenn Randers-Pehrson, and are
 distributed according to the same disclaimer and license as libpng-1.2.5
 with the following individual added to the list of Contributing Authors

@@ -6218,7 +6204,7 @@ certification mark of the Open Source Initiative.

 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-February 21, 2015
+August 8, 2014

 .\" end of man page

--- a/libpngpf.3
+++ b/libpngpf.3
@@ -1,6 +1,6 @@
-.TH LIBPNGPF 3 "February 21, 2015"
+.TH LIBPNGPF 3 "August 8, 2014"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.7.0beta52
+libpng \- Portable Network Graphics (PNG) Reference Library 1.6.13beta04
 (private functions)
 .SH SYNOPSIS
 \fB#include \fI"pngpriv.h"
--- a/png.5
+++ b/png.5
@@ -1,4 +1,4 @@
-.TH PNG 5 "February 21, 2015"
+.TH PNG 5 "August 8, 2014"
 .SH NAME
 png \- Portable Network Graphics (PNG) format
 .SH DESCRIPTION
@@ -24,7 +24,6 @@ PNG specification (second edition), November 2003:
 .IP
 .br
  <http://www.w3.org/TR/2003/REC-PNG-20031110/
-.LP
 PNG 1.2 specification, July 1999:
 .IP
 .br
@@ -59,7 +58,7 @@ Thomas Boutell and others (png-list).

 .SH COPYRIGHT NOTICE
 .LP
-This man page is Copyright (c) 1998-2012 Glenn Randers-Pehrson.  See png.h
+This man page is Copyright (c) 1998-2006 Glenn Randers-Pehrson.  See png.h
 for conditions of use and distribution.
 .LP
 The PNG Specification (Second Edition) is
--- a/png.c
+++ b/png.c
--- a/png.h
+++ b/png.h
@@ -1,8 +1,8 @@

 /* png.h - header file for PNG reference library
 *
- * libpng version 1.7.0beta52 - February 21, 2015
- * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * libpng version 1.6.13beta04 - August 8, 2014
+ * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
@@ -11,7 +11,7 @@
 * Authors and maintainers:
 *   libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
 *   libpng versions 0.89c, June 1996, through 0.96, May 1997: Andreas Dilger
- *   libpng versions 0.97, January 1998, through 1.7.0beta52 - February 21, 2015: Glenn
+ *   libpng versions 0.97, January 1998, through 1.6.13beta04 - August 8, 2014: Glenn
 *   See also "Contributing Authors", below.
 *
 * Note about libpng version numbers:
@@ -166,9 +166,41 @@
 *    1.5.7beta01-05          15    10507  15.so.15.7[.0]
 *    1.5.7rc01-03            15    10507  15.so.15.7[.0]
 *    1.5.7                   15    10507  15.so.15.7[.0]
- *    1.6.0beta01-37          16    10600  16.so.16.0[.0]
- *    1.7.0alpha01-10         17    10700  17.so.17.0[.0]
- *    1.7.0beta01-52          17    10700  17.so.17.0[.0]
+ *    1.6.0beta01-40          16    10600  16.so.16.0[.0]
+ *    1.6.0rc01-08            16    10600  16.so.16.0[.0]
+ *    1.6.0                   16    10600  16.so.16.0[.0]
+ *    1.6.1beta01-09          16    10601  16.so.16.1[.0]
+ *    1.6.1rc01               16    10601  16.so.16.1[.0]
+ *    1.6.1                   16    10601  16.so.16.1[.0]
+ *    1.6.2beta01             16    10602  16.so.16.2[.0]
+ *    1.6.2rc01-06            16    10602  16.so.16.2[.0]
+ *    1.6.2                   16    10602  16.so.16.2[.0]
+ *    1.6.3beta01-11          16    10603  16.so.16.3[.0]
+ *    1.6.3rc01               16    10603  16.so.16.3[.0]
+ *    1.6.3                   16    10603  16.so.16.3[.0]
+ *    1.6.4beta01-02          16    10604  16.so.16.4[.0]
+ *    1.6.4rc01               16    10604  16.so.16.4[.0]
+ *    1.6.4                   16    10604  16.so.16.4[.0]
+ *    1.6.5                   16    10605  16.so.16.5[.0]
+ *    1.6.6                   16    10606  16.so.16.6[.0]
+ *    1.6.7beta01-04          16    10607  16.so.16.7[.0]
+ *    1.6.7rc01-03            16    10607  16.so.16.7[.0]
+ *    1.6.7                   16    10607  16.so.16.7[.0]
+ *    1.6.8beta01-02          16    10608  16.so.16.8[.0]
+ *    1.6.8rc01-02            16    10608  16.so.16.8[.0]
+ *    1.6.8                   16    10608  16.so.16.8[.0]
+ *    1.6.9beta01-04          16    10609  16.so.16.9[.0]
+ *    1.6.9rc01-02            16    10609  16.so.16.9[.0]
+ *    1.6.9                   16    10609  16.so.16.9[.0]
+ *    1.6.10beta01-03         16    10610  16.so.16.10[.0]
+ *    1.6.10rc01-03           16    10610  16.so.16.10[.0]
+ *    1.6.10                  16    10610  16.so.16.10[.0]
+ *    1.6.11beta01-06         16    10611  16.so.16.11[.0]
+ *    1.6.11rc01-02           16    10611  16.so.16.11[.0]
+ *    1.6.11                  16    10611  16.so.16.11[.0]
+ *    1.6.12rc01-03           16    10612  16.so.16.12[.0]
+ *    1.6.12                  16    10612  16.so.16.12[.0]
+ *    1.6.13beta01-04         16    10613  16.so.16.13[.0]
 *
 *   Henceforth the source version will match the shared-library major
 *   and minor numbers; the shared-library major version number will be
@@ -200,8 +232,8 @@
 *
 * This code is released under the libpng license.
 *
- * libpng versions 1.2.6, August 15, 2004, through 1.7.0beta52, February 21, 2015, are
- * Copyright (c) 2004, 2006-2015 Glenn Randers-Pehrson, and are
+ * libpng versions 1.2.6, August 15, 2004, through 1.6.13beta04, August 8, 2014, are
+ * Copyright (c) 2004, 2006-2014 Glenn Randers-Pehrson, and are
 * distributed according to the same disclaimer and license as libpng-1.2.5
 * with the following individual added to the list of Contributing Authors:
 *
@@ -312,13 +344,13 @@
 * Y2K compliance in libpng:
 * =========================
 *
- *    February 21, 2015
+ *    August 8, 2014
 *
 *    Since the PNG Development group is an ad-hoc body, we can't make
 *    an official declaration.
 *
 *    This is your unofficial assurance that libpng from version 0.71 and
- *    upward through 1.7.0beta52 are Y2K compliant.  It is my belief that
+ *    upward through 1.6.13beta04 are Y2K compliant.  It is my belief that
 *    earlier versions were also Y2K compliant.
 *
 *    Libpng only has two year fields.  One is a 2-byte unsigned integer
@@ -380,23 +412,23 @@
 */

 /* Version information for png.h - this should match the version in png.c */
-#define PNG_LIBPNG_VER_STRING "1.7.0beta52"
+#define PNG_LIBPNG_VER_STRING "1.6.13beta04"
 #define PNG_HEADER_VERSION_STRING \
-     " libpng version 1.7.0beta52 - February 21, 2015\n"
+     " libpng version 1.6.13beta04 - August 8, 2014\n"

-#define PNG_LIBPNG_VER_SONUM   17
-#define PNG_LIBPNG_VER_DLLNUM  17
+#define PNG_LIBPNG_VER_SONUM   16
+#define PNG_LIBPNG_VER_DLLNUM  16

 /* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
 #define PNG_LIBPNG_VER_MAJOR   1
-#define PNG_LIBPNG_VER_MINOR   7
-#define PNG_LIBPNG_VER_RELEASE 0
+#define PNG_LIBPNG_VER_MINOR   6
+#define PNG_LIBPNG_VER_RELEASE 13

 /* This should match the numeric part of the final component of
 * PNG_LIBPNG_VER_STRING, omitting any leading zero:
 */

-#define PNG_LIBPNG_VER_BUILD  52
+#define PNG_LIBPNG_VER_BUILD  04

 /* Release Status */
 #define PNG_LIBPNG_BUILD_ALPHA    1
@@ -421,7 +453,7 @@
 * version 1.0.0 was mis-numbered 100 instead of 10000).  From
 * version 1.0.1 it's    xxyyzz, where x=major, y=minor, z=release
 */
-#define PNG_LIBPNG_VER 10700 /* 1.7.0 */
+#define PNG_LIBPNG_VER 10613 /* 1.6.13 */

 /* Library configuration: these options cannot be changed after
 * the library has been built.
@@ -466,6 +498,11 @@

 #ifndef PNG_VERSION_INFO_ONLY

+/* Inhibit C++ name-mangling for libpng functions but not for system calls. */
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
 /* Version information for C files, stored in png.c.  This had better match
 * the version above.
 */
@@ -473,138 +510,17 @@

 /* This file is arranged in several sections:
 *
- * 1. ISO-PNG constants and definitions; values defined by PNG and not specific
- *    to the libpng API.
- * 2. Any configuration options that can be specified by for the application
+ * 1. Any configuration options that can be specified by for the application
 *    code when it is built.  (Build time configuration is in pnglibconf.h)
- * 3. Type definitions (base types are defined in pngconf.h), structure
+ * 2. Type definitions (base types are defined in pngconf.h), structure
 *    definitions.
- * 4. Exported library functions.
- * 5. Simplified API.
+ * 3. Exported library functions.
+ * 4. Simplified API.
 *
 * The library source code has additional files (principally pngpriv.h) that
 * allow configuration of the library.
 */
-
-/* Section 1: ISO PNG constants and macros. */
-
-/* ISO-PNG defines byte encodings for 16 and 32-bit unsigned values and 32-bit
- * signed values.  The macros PNG_U16, PNG_U32 and PNG_S32 return values of type
- * (png_uint_16), (png_uint_32) and (png_int_32) which are target machine
- * specific representations of these values, using the types defined in
- * pngconf.h.  The macros take two or four byte values in the order in which
- * they would occur in a PNG stream.
- *
- * These macros must return compile time constants if passed constant values -
- * machine specific implementations are not permitted.  These macros are used by
- * default in the API functions/macros png_get_uint_16, png_get_uint_32,
- * png_get_uint_31 and png_get_int_32 declared below: these functions or macros
- * are the correct places for machine specific implementations (such as hardware
- * specific instructions.)
- *
- * The macros defined here are generic and intended to give maximum flexibility
- * in implementation to the compiler; only PNG_S32 contains a sequence point,
- * there are no side effects and the expressions used permit the maximum
- * parallelization (relevant because the four bytes may be loaded in parallel.)
- */
-#define PNG_u2(b1, b2) (((unsigned int)(b1) << 8) + (b2))
-
-#define PNG_U16(b1, b2) ((png_uint_16)PNG_u2(b1, b2))
-#define PNG_U32(b1, b2, b3, b4)\
-   (((png_uint_32)PNG_u2(b1, b2) << 16) + PNG_u2(b3, b4))
-
-/* ISO-PNG states that signed 32-bit values are stored in two's complement
- * format.  There is no guarantee that (png_int_32) is exactly 32 bits, so the
- * following macro tests for a negative number and generates the machine format
- * directly by portable arithmetic operations.  The cost is that the argument
- * 'b1' is evaluated twice.
- */
-#define PNG_S32(b1, b2, b3, b4) ((b1) & 0x80\
-      ? -(png_int_32)((PNG_U32(b1, b2, b3, b4) ^ 0xffffffff) + 1)\
-      : (png_int_32)PNG_U32(b1, b2, b3, b4))
-
-/* Constants for known chunk types.
- *
- * MAINTAINERS: If you need to add a chunk, define the name here.
- * For historical reasons these constants have the form png_<name>; i.e.
- * the prefix is lower case.  Please use decimal values as the parameters to
- * match the ISO PNG specification and to avoid relying on the C locale
- * interpretation of character values.  Please keep the list sorted.
- *
- * Notice that PNG_U32 is used to define a 32-bit value for the 4 byte chunk
- * type.  In fact the specification does not express chunk types this way,
- * however using a 32-bit value means that the chunk type can be read from the
- * stream using exactly the same code as used for a 32-bit unsigned value and
- * can be examined far more efficiently (using one arithmetic compare).
- *
- * Prior to 1.5.6 the chunk type constants were expressed as C strings.  The
- * libpng API still uses strings for 'unknown' chunks and a macro,
- * PNG_STRING_FROM_CHUNK, allows a string to be generated if required.  Notice
- * that for portable code numeric values must still be used; the string "IHDR"
- * is not portable and neither is PNG_U32('I', 'H', 'D', 'R').
- *
- * In 1.7.0 the definitions were made public in png.h to avoid having to
- * duplicate the same definitions in application code.
- *
- * SOURCE: http://www.libpng.org/pub/png/spec/register/
- *    "Register of PNG Public Chunks and Keywords, version 1.4.6"
- *    "Extensions to the PNG Specification, version 1.4.0"
- */
-#define png_IDAT PNG_U32( 73,  68,  65,  84)
-#define png_IEND PNG_U32( 73,  69,  78,  68)
-#define png_IHDR PNG_U32( 73,  72,  68,  82)
-#define png_PLTE PNG_U32( 80,  76,  84,  69)
-#define png_bKGD PNG_U32( 98,  75,  71,  68)
-#define png_cHRM PNG_U32( 99,  72,  82,  77)
-#define png_dSIG PNG_U32(100,  83,  73,  71) /* separate spec */
-#define png_fRAc PNG_U32(102,  82,  65,  99) /* registered, not defined */
-#define png_gAMA PNG_U32(103,  65,  77,  65)
-#define png_gIFg PNG_U32(103,  73,  70, 103)
-#define png_gIFt PNG_U32(103,  73,  70, 116) /* deprecated */
-#define png_gIFx PNG_U32(103,  73,  70, 120)
-#define png_hIST PNG_U32(104,  73,  83,  84)
-#define png_iCCP PNG_U32(105,  67,  67,  80)
-#define png_iTXt PNG_U32(105,  84,  88, 116)
-#define png_oFFs PNG_U32(111,  70,  70, 115)
-#define png_pCAL PNG_U32(112,  67,  65,  76)
-#define png_pHYs PNG_U32(112,  72,  89, 115)
-#define png_sBIT PNG_U32(115,  66,  73,  84)
-#define png_sCAL PNG_U32(115,  67,  65,  76)
-#define png_sPLT PNG_U32(115,  80,  76,  84)
-#define png_sRGB PNG_U32(115,  82,  71,  66)
-#define png_sTER PNG_U32(115,  84,  69,  82)
-#define png_tEXt PNG_U32(116,  69,  88, 116)
-#define png_tIME PNG_U32(116,  73,  77,  69)
-#define png_tRNS PNG_U32(116,  82,  78,  83)
-#define png_zTXt PNG_U32(122,  84,  88, 116)
-
-/* The following will work on (signed char*) strings, whereas the PNG_U32 macro
- * used directory would fail on top-bit-set values because of the sign
- * extension.
- */
-#define PNG_CHUNK_FROM_STRING(s)\
-   PNG_U32(0xff&(s)[0], 0xff&(s)[1], 0xff&(s)[2], 0xff&(s)[3])
-
-/* This uses (char), not (png_byte) to avoid warnings on systems where (char) is
- * signed and the argument is a (char[])  This macro will fail miserably on
- * systems where (char) is more than 8 bits.
- */
-#define PNG_STRING_FROM_CHUNK(s,c)\
-   (void)(((char*)(s))[0]=(char)((c)>>24), ((char*)(s))[1]=(char)((c)>>16),\
-   ((char*)(s))[2]=(char)((c)>>8), ((char*)(s))[3]=(char)((c)))
-
-/* Do the same but terminate with a null character. */
-#define PNG_CSTRING_FROM_CHUNK(s,c)\
-   (void)(PNG_STRING_FROM_CHUNK(s,c), ((char*)(s))[4] = 0)
-
-/* Test on flag values as defined in the spec (section 5.4): */
-#define PNG_CHUNK_ANCILLARY(c)    (1 & ((c) >> 29))
-#define PNG_CHUNK_CRITICAL(c)     (!PNG_CHUNK_ANCILLARY(c))
-#define PNG_CHUNK_PRIVATE(c)      (1 & ((c) >> 21))
-#define PNG_CHUNK_RESERVED(c)     (1 & ((c) >> 13))
-#define PNG_CHUNK_SAFE_TO_COPY(c) (1 & ((c) >>  5))
-
-/* Section 2: run time configuration
+/* Section 1: run time configuration
 * See pnglibconf.h for build time configuration
 *
 * Run time configuration allows the application to choose between
@@ -634,12 +550,7 @@
 * Otherwise the calls are mapped to png_error.
 */

-/* Inhibit C++ name-mangling for libpng functions but not for system calls. */
-#ifdef __cplusplus
-extern "C" {
-#endif /* __cplusplus */
-
-/* Section 3: type definitions, including structures and compile time
+/* Section 2: type definitions, including structures and compile time
 * constants.
 * See pngconf.h for base types that vary by machine/system
 */
@@ -647,7 +558,7 @@ extern "C" {
 /* This triggers a compiler error in png.c, if png.c and png.h
 * do not agree upon the version number.
 */
-typedef char* png_libpng_version_1_7_0beta52;
+typedef char* png_libpng_version_1_6_13beta04;

 /* Basic control structions.  Read libpng-manual.txt or libpng.3 for more info.
 *
@@ -788,8 +699,8 @@ typedef struct png_text_struct
   png_charp key;          /* keyword, 1-79 character description of "text" */
   png_charp text;         /* comment, may be an empty string (ie "")
                              or a NULL pointer */
-   size_t text_length; /* length of the text string */
-   size_t itxt_length; /* length of the itxt string */
+   png_size_t text_length; /* length of the text string */
+   png_size_t itxt_length; /* length of the itxt string */
   png_charp lang;         /* language code, 0-79 characters
                              or a NULL pointer */
   png_charp lang_key;     /* keyword translated UTF-8 string, 0 or more
@@ -842,7 +753,7 @@ typedef struct png_unknown_chunk_t
 {
    png_byte name[5]; /* Textual chunk name with '\0' terminator */
    png_byte *data;   /* Data, should not be modified on read! */
-    size_t size;
+    png_size_t size;

    /* On write 'location' must be set using the flag values listed below.
     * Notice that on read it is set by libpng however the values stored have
@@ -867,7 +778,7 @@ typedef png_unknown_chunk * * png_unknown_chunkpp;
 /* Maximum positive integer used in PNG is (2^31)-1 */
 #define PNG_UINT_31_MAX ((png_uint_32)0x7fffffffL)
 #define PNG_UINT_32_MAX ((png_uint_32)(-1))
-#define PNG_SIZE_MAX ((size_t)(-1))
+#define PNG_SIZE_MAX ((png_size_t)(-1))

 /* These are constants for fixed point values encoded in the
 * PNG specification manner (x100000)
@@ -972,7 +883,7 @@ typedef png_unknown_chunk * * png_unknown_chunkpp;
 typedef struct png_row_info_struct
 {
   png_uint_32 width;    /* width of row */
-   size_t rowbytes;  /* number of bytes in row */
+   png_size_t rowbytes;  /* number of bytes in row */
   png_byte color_type;  /* color type of row */
   png_byte bit_depth;   /* bit depth of row */
   png_byte channels;    /* number of channels (1, 2, 3, or 4) */
@@ -991,7 +902,7 @@ typedef png_row_info * * png_row_infopp;
 * expected to return the read data in the buffer.
 */
 typedef PNG_CALLBACK(void, *png_error_ptr, (png_structp, png_const_charp));
-typedef PNG_CALLBACK(void, *png_rw_ptr, (png_structp, png_bytep, size_t));
+typedef PNG_CALLBACK(void, *png_rw_ptr, (png_structp, png_bytep, png_size_t));
 typedef PNG_CALLBACK(void, *png_flush_ptr, (png_structp));
 typedef PNG_CALLBACK(void, *png_read_status_ptr, (png_structp, png_uint_32,
    int));
@@ -1084,7 +995,7 @@ typedef PNG_CALLBACK(png_voidp, *png_malloc_ptr, (png_structp,
    png_alloc_size_t));
 typedef PNG_CALLBACK(void, *png_free_ptr, (png_structp, png_voidp));

-/* Section 4: exported functions
+/* Section 3: exported functions
 * Here are the function definitions most commonly used.  This is not
 * the place to find out how to use libpng.  See libpng-manual.txt for the
 * full explanation, see example.c for the summary.  This just provides
@@ -1126,8 +1037,8 @@ PNG_EXPORT(2, void, png_set_sig_bytes, (png_structrp png_ptr, int num_bytes));
 * signature, and non-zero otherwise.  Having num_to_check == 0 or
 * start > 7 will always fail (ie return non-zero).
 */
-PNG_EXPORT(3, int, png_sig_cmp, (png_const_bytep sig, size_t start,
-    size_t num_to_check));
+PNG_EXPORT(3, int, png_sig_cmp, (png_const_bytep sig, png_size_t start,
+    png_size_t num_to_check));

 /* Simple signature checking function.  This is the same as calling
 * png_check_sig(sig, n) := !png_sig_cmp(sig, 0, n).
@@ -1146,11 +1057,11 @@ PNG_EXPORTA(5, png_structp, png_create_write_struct,
    png_error_ptr warn_fn),
    PNG_ALLOCATED);

-PNG_EXPORT(6, size_t, png_get_compression_buffer_size,
+PNG_EXPORT(6, png_size_t, png_get_compression_buffer_size,
    (png_const_structrp png_ptr));

 PNG_EXPORT(7, void, png_set_compression_buffer_size, (png_structrp png_ptr,
-    size_t size));
+    png_size_t size));

 /* Moved from pngconf.h in 1.4.0 and modified to ensure setjmp/longjmp
 * match up.
@@ -1180,8 +1091,8 @@ PNG_EXPORTA(9, void, png_longjmp, (png_const_structrp png_ptr, int val),
    PNG_NORETURN);

 #ifdef PNG_READ_SUPPORTED
-/* Reset the compression stream -- Removed from libpng-1.7.0 */
-PNG_REMOVED(10, int, png_reset_zstream, (png_structrp png_ptr), PNG_DEPRECATED)
+/* Reset the compression stream */
+PNG_EXPORTA(10, int, png_reset_zstream, (png_structrp png_ptr), PNG_DEPRECATED);
 #endif

 /* New functions added in libpng-1.0.2 (not enabled by default until 1.2.0) */
@@ -1203,7 +1114,7 @@ PNG_EXPORT(13, void, png_write_sig, (png_structrp png_ptr));

 /* Write a PNG chunk - size, type, (optional) data, CRC. */
 PNG_EXPORT(14, void, png_write_chunk, (png_structrp png_ptr, png_const_bytep
-    chunk_name, png_const_bytep data, size_t length));
+    chunk_name, png_const_bytep data, png_size_t length));

 /* Write the start of a PNG chunk - length and chunk name. */
 PNG_EXPORT(15, void, png_write_chunk_start, (png_structrp png_ptr,
@@ -1211,7 +1122,7 @@ PNG_EXPORT(15, void, png_write_chunk_start, (png_structrp png_ptr,

 /* Write the data of a PNG chunk started with png_write_chunk_start(). */
 PNG_EXPORT(16, void, png_write_chunk_data, (png_structrp png_ptr,
-    png_const_bytep data, size_t length));
+    png_const_bytep data, png_size_t length));

 /* Finish a chunk started with png_write_chunk_start() (includes CRC). */
 PNG_EXPORT(17, void, png_write_chunk_end, (png_structrp png_ptr));
@@ -1220,9 +1131,12 @@ PNG_EXPORT(17, void, png_write_chunk_end, (png_structrp png_ptr));
 PNG_EXPORTA(18, png_infop, png_create_info_struct, (png_const_structrp png_ptr),
    PNG_ALLOCATED);

-/* Removed from libpng-1.7.0 */
-PNG_REMOVED(19, void, png_info_init_3, (png_infopp info_ptr,
-    size_t png_info_struct_size), PNG_DEPRECATED)
+/* DEPRECATED: this function allowed init structures to be created using the
+ * default allocation method (typically malloc).  Use is deprecated in 1.6.0 and
+ * the API will be removed in the future.
+ */
+PNG_EXPORTA(19, void, png_info_init_3, (png_infopp info_ptr,
+    png_size_t png_info_struct_size), PNG_DEPRECATED);

 /* Writes all the PNG information before the image. */
 PNG_EXPORT(20, void, png_write_info_before_PLTE,
@@ -1239,10 +1153,13 @@ PNG_EXPORT(22, void, png_read_info,
 #ifdef PNG_TIME_RFC1123_SUPPORTED
   /* Convert to a US string format: there is no localization support in this
    * routine.  The original implementation used a 29 character buffer in
-    * png_struct, this has been removed (in libpng 1.7.0).
+    * png_struct, this will be removed in future versions.
    */
-PNG_REMOVED(23, png_const_charp, png_convert_to_rfc1123, (png_structrp png_ptr,
-    png_const_timep ptime),PNG_DEPRECATED)
+#if PNG_LIBPNG_VER < 10700
+/* To do: remove this from libpng17 (and from libpng17/png.c and pngstruct.h) */
+PNG_EXPORTA(23, png_const_charp, png_convert_to_rfc1123, (png_structrp png_ptr,
+    png_const_timep ptime),PNG_DEPRECATED);
+#endif
 PNG_EXPORT(241, int, png_convert_to_rfc1123_buffer, (char out[29],
    png_const_timep ptime));
 #endif
@@ -1254,7 +1171,7 @@ PNG_EXPORT(24, void, png_convert_from_struct_tm, (png_timep ptime,

 /* Convert from time_t to png_time.  Uses gmtime() */
 PNG_EXPORT(25, void, png_convert_from_time_t, (png_timep ptime, time_t ttime));
-#endif /* CONVERT_tIME */
+#endif /* PNG_CONVERT_tIME_SUPPORTED */

 #ifdef PNG_READ_EXPAND_SUPPORTED
 /* Expand data to 24-bit RGB, or 8-bit grayscale, with alpha if available. */
@@ -1460,7 +1377,7 @@ PNG_EXPORT(39, void, png_set_filler, (png_structrp png_ptr, png_uint_32 filler,
 /* Add an alpha byte to 8-bit Gray or 24-bit RGB images. */
 PNG_EXPORT(40, void, png_set_add_alpha, (png_structrp png_ptr,
    png_uint_32 filler, int flags));
-#endif /* READ_FILLER || WRITE_FILLER */
+#endif /* PNG_READ_FILLER_SUPPORTED || PNG_WRITE_FILLER_SUPPORTED */

 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
 /* Swap bytes in 16-bit depth files. */
@@ -1664,8 +1581,22 @@ PNG_EXPORT(66, void, png_set_crc_action, (png_structrp png_ptr, int crit_action,
 PNG_EXPORT(67, void, png_set_filter, (png_structrp png_ptr, int method,
    int filters));

+/* Flags for png_set_filter() to say which filters to use.  The flags
+ * are chosen so that they don't conflict with real filter types
+ * below, in case they are supplied instead of the #defined constants.
+ * These values should NOT be changed.
+ */
+#define PNG_NO_FILTERS     0x00
+#define PNG_FILTER_NONE    0x08
+#define PNG_FILTER_SUB     0x10
+#define PNG_FILTER_UP      0x20
+#define PNG_FILTER_AVG     0x40
+#define PNG_FILTER_PAETH   0x80
+#define PNG_ALL_FILTERS (PNG_FILTER_NONE | PNG_FILTER_SUB | PNG_FILTER_UP | \
+                         PNG_FILTER_AVG | PNG_FILTER_PAETH)
+
 /* Filter values (not flags) - used in pngwrite.c, pngwutil.c for now.
- * These defines match the values in the PNG specification.
+ * These defines should NOT be changed.
 */
 #define PNG_FILTER_VALUE_NONE  0
 #define PNG_FILTER_VALUE_SUB   1
@@ -1674,26 +1605,6 @@ PNG_EXPORT(67, void, png_set_filter, (png_structrp png_ptr, int method,
 #define PNG_FILTER_VALUE_PAETH 4
 #define PNG_FILTER_VALUE_LAST  5

-/* The above values are valid arguments to png_set_filter() if only a single
- * filter is to be used.  If multiple filters are to be allowed (the default is
- * to allow any of them) then a combination of the following masks must be used
- * and the low three bits of the argument to png_set_filter must be 0.
- *
- * The resultant argument fits in a single byte.
- */
-#define PNG_FILTER_NONE    (0x08 << PNG_FILTER_VALUE_NONE)
-#define PNG_FILTER_SUB     (0x08 << PNG_FILTER_VALUE_SUB)
-#define PNG_FILTER_UP      (0x08 << PNG_FILTER_VALUE_UP)
-#define PNG_FILTER_AVG     (0x08 << PNG_FILTER_VALUE_AVG)
-#define PNG_FILTER_PAETH   (0x08 << PNG_FILTER_VALUE_PAETH)
-
-/* Then two convenience values.  PNG_NO_FILTERS is the same as
- * PNG_FILTER_VALUE_NONE, but this is harmless because they mean the same thing.
- */
-#define PNG_NO_FILTERS     0x00
-#define PNG_ALL_FILTERS    (PNG_FILTER_NONE | PNG_FILTER_SUB | PNG_FILTER_UP | \
-   PNG_FILTER_AVG | PNG_FILTER_PAETH)
-
 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* EXPERIMENTAL */
 /* The "heuristic_method" is given by one of the PNG_FILTER_HEURISTIC_
 * defines, either the default (minimum-sum-of-absolute-differences), or
@@ -1730,7 +1641,7 @@ PNG_FIXED_EXPORT(209, void, png_set_filter_heuristics_fixed,
    (png_structrp png_ptr, int heuristic_method, int num_weights,
    png_const_fixed_point_p filter_weights,
    png_const_fixed_point_p filter_costs))
-#endif /*  WRITE_WEIGHTED_FILTER */
+#endif /*  PNG_WRITE_WEIGHTED_FILTER_SUPPORTED */

 /* Heuristic used for row filter selection.  These defines should NOT be
 * changed.
@@ -1748,7 +1659,6 @@ PNG_FIXED_EXPORT(209, void, png_set_filter_heuristics_fixed,
 * for PNG images, and do considerably fewer caclulations.  In the future,
 * these values may not correspond directly to the zlib compression levels.
 */
-#ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
 PNG_EXPORT(69, void, png_set_compression_level, (png_structrp png_ptr,
    int level));

@@ -1766,7 +1676,7 @@ PNG_EXPORT(72, void, png_set_compression_window_bits, (png_structrp png_ptr,

 PNG_EXPORT(73, void, png_set_compression_method, (png_structrp png_ptr,
    int method));
-#endif /* WRITE_CUSTOMIZE_COMPRESSION */
+#endif

 #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
 /* Also set zlib parameters for compressing non-IDAT chunks */
@@ -1787,8 +1697,7 @@ PNG_EXPORT(225, void, png_set_text_compression_window_bits,

 PNG_EXPORT(226, void, png_set_text_compression_method, (png_structrp png_ptr,
    int method));
-#endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
-#endif /* WRITE */
+#endif /* PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED */

 /* These next functions are called for input/output, memory, and error
 * handling.  They are in the file pngrio.c, pngwio.c, and pngerror.c,
@@ -1900,14 +1809,12 @@ PNG_EXPORT(218, png_byte, png_get_current_pass_number, (png_const_structrp));
 * The integer return from the callback function is interpreted thus:
 *
 * negative: An error occured, png_chunk_error will be called.
- *     zero: The chunk was not handled, the default unknown handling is used
- *           (even if this was a chunk that would otherwise be known.)
- *           NOTE: prior to libpng 1.7 handling values of
- *           PNG_HANDLE_CHUNK_AS_DEFAULT and PNG_HANDLE_CHUNK_NEVER were
- *           converted to PNG_HANDLE_CHUNK_IF_SAFE (libpng 1.6.0 warns if this
- *           happens) so it was not possible to discard unknown chunk data if a
- *           user callback was installed.
+ *     zero: The chunk was not handled, the chunk will be saved. A critical
+ *           chunk will cause an error at this point unless it is to be saved.
 * positive: The chunk was handled, libpng will ignore/discard it.
+ *
+ * See "INTERACTION WTIH USER CHUNK CALLBACKS" below for important notes about
+ * how this behavior will change in libpng 1.7
 */
 PNG_EXPORT(88, void, png_set_read_user_chunk_fn, (png_structrp png_ptr,
    png_voidp user_chunk_ptr, png_user_chunk_ptr read_user_chunk_fn));
@@ -1931,7 +1838,7 @@ PNG_EXPORT(91, png_voidp, png_get_progressive_ptr,

 /* Function to be called when data becomes available */
 PNG_EXPORT(92, void, png_process_data, (png_structrp png_ptr,
-    png_inforp info_ptr, png_bytep buffer, size_t buffer_size));
+    png_inforp info_ptr, png_bytep buffer, png_size_t buffer_size));

 /* A function which may be called *only* within png_process_data to stop the
 * processing of any more data.  The function returns the number of bytes
@@ -1940,7 +1847,7 @@ PNG_EXPORT(92, void, png_process_data, (png_structrp png_ptr,
 * 'save' is set to true the routine will first save all the pending data and
 * will always return 0.
 */
-PNG_EXPORT(219, size_t, png_process_data_pause, (png_structrp, int save));
+PNG_EXPORT(219, png_size_t, png_process_data_pause, (png_structrp, int save));

 /* A function which may be called *only* outside (after) a call to
 * png_process_data.  It returns the number of bytes of data to skip in the
@@ -1950,7 +1857,6 @@ PNG_EXPORT(219, size_t, png_process_data_pause, (png_structrp, int save));
 */
 PNG_EXPORT(220, png_uint_32, png_process_data_skip, (png_structrp));

-#ifdef PNG_READ_INTERLACING_SUPPORTED
 /* Function that combines rows.  'new_row' is a flag that should come from
 * the callback and be non-NULL if anything needs to be done; the library
 * stores its own version of the new data internally and ignores the passed
@@ -1958,8 +1864,7 @@ PNG_EXPORT(220, png_uint_32, png_process_data_skip, (png_structrp));
 */
 PNG_EXPORT(93, void, png_progressive_combine_row, (png_const_structrp png_ptr,
    png_bytep old_row, png_const_bytep new_row));
-#endif /* READ_INTERLACING */
-#endif /* PROGRESSIVE_READ */
+#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */

 PNG_EXPORTA(94, png_voidp, png_malloc, (png_const_structrp png_ptr,
    png_alloc_size_t size), PNG_ALLOCATED);
@@ -1983,13 +1888,16 @@ PNG_EXPORT(98, void, png_free_data, (png_const_structrp png_ptr,
 * in, it does not change the state for other png_info structures.
 *
 * It is unlikely that this function works correctly as of 1.6.0 and using it
- * may result either in memory leaks or double free of allocated data. It was
- * removed in libpng 1.7.0.
+ * may result either in memory leaks or double free of allocated data.
 */
-PNG_REMOVED(99, void, png_data_freer, (png_const_structrp png_ptr,
-    png_inforp info_ptr, int freer, png_uint_32 mask), PNG_DEPRECATED)
+PNG_EXPORT(99, void, png_data_freer, (png_const_structrp png_ptr,
+    png_inforp info_ptr, int freer, png_uint_32 mask));

-/* Flags for png_free_data */
+/* Assignments for png_data_freer */
+#define PNG_DESTROY_WILL_FREE_DATA 1
+#define PNG_SET_WILL_FREE_DATA 1
+#define PNG_USER_WILL_FREE_DATA 2
+/* Flags for png_ptr->free_me and info_ptr->free_me */
 #define PNG_FREE_HIST 0x0008
 #define PNG_FREE_ICCP 0x0010
 #define PNG_FREE_SPLT 0x0020
@@ -2007,14 +1915,10 @@ PNG_REMOVED(99, void, png_data_freer, (png_const_structrp png_ptr,
 #define PNG_FREE_MUL  0x4220 /* PNG_FREE_SPLT|PNG_FREE_TEXT|PNG_FREE_UNKN */

 #ifdef PNG_USER_MEM_SUPPORTED
-   /* These were deprecated in libpng 1.6.0 and have been removed from libpng
-    * 1.7.0; the functionality should be accessed by calling malloc or free
-    * directly or, if png_error handling is required, calling png_malloc.
-    */
-PNG_REMOVED(100, png_voidp, png_malloc_default, (png_const_structrp png_ptr,
-    png_alloc_size_t size), PNG_ALLOCATED PNG_DEPRECATED)
-PNG_REMOVED(101, void, png_free_default, (png_const_structrp png_ptr,
-    png_voidp ptr), PNG_DEPRECATED)
+PNG_EXPORTA(100, png_voidp, png_malloc_default, (png_const_structrp png_ptr,
+    png_alloc_size_t size), PNG_ALLOCATED PNG_DEPRECATED);
+PNG_EXPORTA(101, void, png_free_default, (png_const_structrp png_ptr,
+    png_voidp ptr), PNG_DEPRECATED);
 #endif

 #ifdef PNG_ERROR_TEXT_SUPPORTED
@@ -2087,7 +1991,7 @@ PNG_EXPORT(110, png_uint_32, png_get_valid, (png_const_structrp png_ptr,
    png_const_inforp info_ptr, png_uint_32 flag));

 /* Returns number of bytes needed to hold a transformed row. */
-PNG_EXPORT(111, size_t, png_get_rowbytes, (png_const_structrp png_ptr,
+PNG_EXPORT(111, png_size_t, png_get_rowbytes, (png_const_structrp png_ptr,
    png_const_inforp info_ptr));

 #ifdef PNG_INFO_IMAGE_SUPPORTED
@@ -2161,7 +2065,7 @@ PNG_EXPORT(128, png_int_32, png_get_x_offset_microns,
 PNG_EXPORT(129, png_int_32, png_get_y_offset_microns,
    (png_const_structrp png_ptr, png_const_inforp info_ptr));

-#endif /* EASY_ACCESS */
+#endif /* PNG_EASY_ACCESS_SUPPORTED */

 #ifdef PNG_READ_SUPPORTED
 /* Returns pointer to signature string read from PNG header */
@@ -2343,7 +2247,7 @@ PNG_EXPORT(160, int, png_get_sPLT, (png_const_structrp png_ptr,
 #endif

 #ifdef PNG_sPLT_SUPPORTED
-PNG_EXPORT(161, void, png_set_sPLT, (png_structrp png_ptr,
+PNG_EXPORT(161, void, png_set_sPLT, (png_const_structrp png_ptr,
    png_inforp info_ptr, png_const_sPLT_tp entries, int nentries));
 #endif

@@ -2361,7 +2265,7 @@ PNG_EXPORT(162, int, png_get_text, (png_const_structrp png_ptr,
 */

 #ifdef PNG_TEXT_SUPPORTED
-PNG_EXPORT(163, void, png_set_text, (png_structrp png_ptr,
+PNG_EXPORT(163, void, png_set_text, (png_const_structrp png_ptr,
    png_inforp info_ptr, png_const_textp text_ptr, int num_text));
 #endif

@@ -2388,14 +2292,15 @@ PNG_EXPORT(167, void, png_set_tRNS, (png_structrp png_ptr,
 #endif

 #ifdef PNG_sCAL_SUPPORTED
-#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
-/* NOTE: these API are currently implemented using floating point arithmetic,
- * consequently they can only be used on systems with floating point support.
+PNG_FP_EXPORT(168, png_uint_32, png_get_sCAL, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr, int *unit, double *width, double *height))
+#if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || \
+   defined(PNG_FLOATING_POINT_SUPPORTED)
+/* NOTE: this API is currently implemented using floating point arithmetic,
+ * consequently it can only be used on systems with floating point support.
 * In any case the range of values supported by png_fixed_point is small and it
 * is highly recommended that png_get_sCAL_s be used instead.
 */
-PNG_FP_EXPORT(168, png_uint_32, png_get_sCAL, (png_const_structrp png_ptr,
-    png_const_inforp info_ptr, int *unit, double *width, double *height))
 PNG_FIXED_EXPORT(214, png_uint_32, png_get_sCAL_fixed,
    (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit,
    png_fixed_point *width, png_fixed_point *height))
@@ -2404,20 +2309,15 @@ PNG_EXPORT(169, png_uint_32, png_get_sCAL_s,
    (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit,
    png_charpp swidth, png_charpp sheight));

-#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
-/* This also requires internal floating point arithmetic support - i.e. it
- * requires a full math library, not just floating point handling.
- */
 PNG_FP_EXPORT(170, void, png_set_sCAL, (png_const_structrp png_ptr,
    png_inforp info_ptr, int unit, double width, double height))
-#endif
 PNG_FIXED_EXPORT(213, void, png_set_sCAL_fixed, (png_const_structrp png_ptr,
   png_inforp info_ptr, int unit, png_fixed_point width,
   png_fixed_point height))
 PNG_EXPORT(171, void, png_set_sCAL_s, (png_const_structrp png_ptr,
    png_inforp info_ptr, int unit,
    png_const_charp swidth, png_const_charp sheight));
-#endif /* sCAL */
+#endif /* PNG_sCAL_SUPPORTED */

 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
 /* Provide the default handling for all unknown chunks or, optionally, for
@@ -2426,14 +2326,9 @@ PNG_EXPORT(171, void, png_set_sCAL_s, (png_const_structrp png_ptr,
 * NOTE: prior to 1.6.0 the handling specified for particular chunks on read was
 * ignored and the default was used, the per-chunk setting only had an effect on
 * write.  If you wish to have chunk-specific handling on read in code that must
- * work on earlier versions you must use a user chunk callback to implement the
+ * work on earlier versions you must use a user chunk callback to specify the
 * desired handling (keep or discard.)
 *
- * NOTE: prior to 1.7.0 when a user callback returned '0', indicating that the
- * chunk had not been handled, libpng would preserve it regardless of the
- * default or per-chunk settings.  For compatibility with earlier versions
- * simply return '1' (handled) from the callback to discard the chunk.
- *
 * The 'keep' parameter is a PNG_HANDLE_CHUNK_ value as listed below.  The
 * parameter is interpreted as follows:
 *
@@ -2456,12 +2351,21 @@ PNG_EXPORT(171, void, png_set_sCAL_s, (png_const_structrp png_ptr,
 * to specifying "NEVER", however when "AS_DEFAULT" is used for specific chunks
 * it simply resets the behavior to the libpng default.
 *
+ * INTERACTION WTIH USER CHUNK CALLBACKS:
 * The per-chunk handling is always used when there is a png_user_chunk_ptr
 * callback and the callback returns 0; the chunk is then always stored *unless*
 * it is critical and the per-chunk setting is other than ALWAYS.  Notice that
 * the global default is *not* used in this case.  (In effect the per-chunk
 * value is incremented to at least IF_SAFE.)
 *
+ * IMPORTANT NOTE: this behavior will change in libpng 1.7 - the global and
+ * per-chunk defaults will be honored.  If you want to preserve the current
+ * behavior when your callback returns 0 you must set PNG_HANDLE_CHUNK_IF_SAFE
+ * as the default - if you don't do this libpng 1.6 will issue a warning.
+ *
+ * If you want unhandled unknown chunks to be discarded in libpng 1.6 and
+ * earlier simply return '1' (handled).
+ *
 * PNG_HANDLE_AS_UNKNOWN_SUPPORTED:
 *    If this is *not* set known chunks will always be handled by libpng and
 *    will never be stored in the unknown chunk list.  Known chunks listed to
@@ -2526,7 +2430,7 @@ PNG_EXPORT(173, int, png_handle_as_unknown, (png_const_structrp png_ptr,
 #endif

 #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
-PNG_EXPORT(174, void, png_set_unknown_chunks, (png_structrp png_ptr,
+PNG_EXPORT(174, void, png_set_unknown_chunks, (png_const_structrp png_ptr,
    png_inforp info_ptr, png_const_unknown_chunkp unknowns,
    int num_unknowns));
   /* NOTE: prior to 1.6.0 this routine set the 'location' field of the added
@@ -2641,8 +2545,8 @@ PNG_FIXED_EXPORT(212, png_fixed_point, png_get_y_offset_inches_fixed,
 PNG_EXPORT(198, png_uint_32, png_get_pHYs_dpi, (png_const_structrp png_ptr,
    png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y,
    int *unit_type));
-#  endif /* pHYs */
-#endif  /* INCH_CONVERSIONS */
+#  endif /* PNG_pHYs_SUPPORTED */
+#endif  /* PNG_INCH_CONVERSIONS_SUPPORTED */

 /* Added in libpng-1.4.0 */
 #ifdef PNG_IO_STATE_SUPPORTED
@@ -2665,7 +2569,7 @@ PNG_EXPORT(216, png_uint_32, png_get_io_chunk_type,
 #  define PNG_IO_CHUNK_CRC   0x0080   /* currently at the chunk crc */
 #  define PNG_IO_MASK_OP     0x000f   /* current operation: reading/writing */
 #  define PNG_IO_MASK_LOC    0x00f0   /* current location: sig/hdr/data/crc */
-#endif /* IO_STATE */
+#endif /* ?PNG_IO_STATE_SUPPORTED */

 /* Interlace support.  The following macros are always defined so that if
 * libpng interlace handling is turned off the macros may be used to handle
@@ -2769,7 +2673,7 @@ PNG_EXPORT(216, png_uint_32, png_get_io_chunk_type,
     (composite) = (png_uint_16)(((png_uint_32)(fg) * (png_uint_32)(alpha) + \
     (png_uint_32)(bg)*(png_uint_32)(65535 - (png_uint_32)(alpha)) +         \
     32767) / 65535)
-#endif /* READ_COMPOSITE_NODIV */
+#endif /* PNG_READ_COMPOSITE_NODIV_SUPPORTED */

 #ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
 PNG_EXPORT(201, png_uint_32, png_get_uint_32, (png_const_bytep buf));
@@ -2800,18 +2704,27 @@ PNG_EXPORT(207, void, png_save_uint_16, (png_bytep buf, unsigned int i));

 #ifdef PNG_USE_READ_MACROS
 /* Inline macros to do direct reads of bytes from the input buffer.
+ * The png_get_int_32() routine assumes we are using two's complement
+ * format for negative values, which is almost certainly true.
 */
-#  define PNG_B(ptr, offset) (((png_const_bytep)(ptr))[offset])
 #  define PNG_get_uint_32(buf) \
-      PNG_U32(PNG_B(buf,0), PNG_B(buf,1), PNG_B(buf,2), PNG_B(buf,3))
+     (((png_uint_32)(*(buf)) << 24) + \
+      ((png_uint_32)(*((buf) + 1)) << 16) + \
+      ((png_uint_32)(*((buf) + 2)) << 8) + \
+      ((png_uint_32)(*((buf) + 3))))

   /* From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
    * function) incorrectly returned a value of type png_uint_32.
    */
-#  define PNG_get_uint_16(buf) PNG_U16(PNG_B(buf,0), PNG_B(buf,1))
+#  define PNG_get_uint_16(buf) \
+     ((png_uint_16) \
+      (((unsigned int)(*(buf)) << 8) + \
+       ((unsigned int)(*((buf) + 1)))))

 #  define PNG_get_int_32(buf) \
-      PNG_S32(PNG_B(buf,0), PNG_B(buf,1), PNG_B(buf,2), PNG_B(buf,3))
+     ((png_int_32)((*(buf) & 0x80) \
+      ? -((png_int_32)((png_get_uint_32(buf) ^ 0xffffffffL) + 1)) \
+      : (png_int_32)png_get_uint_32(buf)))

   /* If PNG_PREFIX is defined the same thing as below happens in pnglibconf.h,
    * but defining a macro name prefixed with PNG_PREFIX.
@@ -2830,64 +2743,8 @@ PNG_EXPORT(207, void, png_save_uint_16, (png_bytep buf, unsigned int i));
 #  endif
 #endif

-#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
-PNG_EXPORT(242, void, png_set_check_for_invalid_index,
-    (png_structrp png_ptr, int allowed));
-#  ifdef PNG_GET_PALETTE_MAX_SUPPORTED
-PNG_EXPORT(243, int, png_get_palette_max, (png_const_structrp png_ptr,
-    png_const_inforp info_ptr));
-#  endif
-#endif /* CHECK_FOR_INVALID_INDEX */
-
 /*******************************************************************************
- *  IMPLEMENTATION OPTIONS
- *******************************************************************************
- *
- * Support for arbitrary implementation-specific optimizations.  The API allows
- * particular options to be turned on or off.  'Option' is the number of the
- * option and 'onoff' is 0 (off) or non-0 (on).  The value returned is given
- * by the PNG_OPTION_ defines below.
- *
- * HARDWARE: normally hardware capabilites, such as the Intel SSE instructions,
- *           are detected at run time, however sometimes it may be impossible
- *           to do this in user mode, in which case it is necessary to discover
- *           the capabilities in an OS specific way.  Such capabilities are
- *           listed here when libpng has support for them and must be turned
- *           ON by the application if present.
- *
- * SOFTWARE: sometimes software optimizations actually result in performance
- *           decrease on some architectures or systems, or with some sets of
- *           PNG images.  'Software' options allow such optimizations to be
- *           selected at run time.
- */
-#ifdef PNG_SET_OPTION_SUPPORTED
-#ifdef PNG_ARM_NEON_API_SUPPORTED
-#  define PNG_ARM_NEON   0 /* HARDWARE: ARM Neon SIMD instructions supported */
-#endif
-#define PNG_MAXIMUM_INFLATE_WINDOW 2 /* SOFTWARE: force maximum window */
-#define PNG_SKIP_sRGB_CHECK_PROFILE 4 /* SOFTWARE: Check ICC profile for sRGB */
-#define PNG_OPTION_NEXT  6 /* Next option - numbers must be even */
-
-/* Return values: NOTE: there are four values and 'off' is *not* zero */
-#define PNG_OPTION_UNSET   0 /* Unset - defaults to off */
-#define PNG_OPTION_INVALID 1 /* Option number out of range */
-#define PNG_OPTION_OFF     2
-#define PNG_OPTION_ON      3
-
-PNG_EXPORT(244, int, png_set_option, (png_structrp png_ptr, int option,
-   int onoff));
-#endif
-
-/*******************************************************************************
- *  END OF HARDWARE OPTIONS
- ******************************************************************************/
-
-/* Maintainer: Put new public prototypes here ^, in libpng.3, and project
- * defs
- */
-
-/*******************************************************************************
- *  Section 5: SIMPLIFIED API
+ *  SIMPLIFIED API
 *******************************************************************************
 *
 * Please read the documentation in libpng-manual.txt (TODO: write said
@@ -3242,10 +3099,10 @@ PNG_EXPORT(234, int, png_image_begin_read_from_file, (png_imagep image,
 PNG_EXPORT(235, int, png_image_begin_read_from_stdio, (png_imagep image,
   FILE* file));
   /* The PNG header is read from the stdio FILE object. */
-#endif /* STDIO */
+#endif /* PNG_STDIO_SUPPORTED */

 PNG_EXPORT(236, int, png_image_begin_read_from_memory, (png_imagep image,
-   png_const_voidp memory, size_t size));
+   png_const_voidp memory, png_size_t size));
   /* The PNG header is read from the given memory buffer. */

 PNG_EXPORT(237, int, png_image_finish_read, (png_imagep image,
@@ -3287,7 +3144,7 @@ PNG_EXPORT(238, void, png_image_free, (png_imagep image));
   /* Free any data allocated by libpng in image->opaque, setting the pointer to
    * NULL.  May be called at any time after the structure is initialized.
    */
-#endif /* SIMPLIFIED_READ */
+#endif /* PNG_SIMPLIFIED_READ_SUPPORTED */

 #ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
 #ifdef PNG_STDIO_SUPPORTED
@@ -3333,12 +3190,68 @@ PNG_EXPORT(240, int, png_image_write_to_stdio, (png_imagep image, FILE *file,
 *
 * Note that the write API does not support interlacing or sub-8-bit pixels.
 */
-#endif /* STDIO */
-#endif /* SIMPLIFIED_WRITE */
+#endif /* PNG_STDIO_SUPPORTED */
+#endif /* PNG_SIMPLIFIED_WRITE_SUPPORTED */
 /*******************************************************************************
 *  END OF SIMPLIFIED API
 ******************************************************************************/

+#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
+PNG_EXPORT(242, void, png_set_check_for_invalid_index,
+    (png_structrp png_ptr, int allowed));
+#  ifdef PNG_GET_PALETTE_MAX_SUPPORTED
+PNG_EXPORT(243, int, png_get_palette_max, (png_const_structp png_ptr,
+    png_const_infop info_ptr));
+#  endif
+#endif /* CHECK_FOR_INVALID_INDEX */
+
+/*******************************************************************************
+ *  IMPLEMENTATION OPTIONS
+ *******************************************************************************
+ *
+ * Support for arbitrary implementation-specific optimizations.  The API allows
+ * particular options to be turned on or off.  'Option' is the number of the
+ * option and 'onoff' is 0 (off) or non-0 (on).  The value returned is given
+ * by the PNG_OPTION_ defines below.
+ *
+ * HARDWARE: normally hardware capabilites, such as the Intel SSE instructions,
+ *           are detected at run time, however sometimes it may be impossible
+ *           to do this in user mode, in which case it is necessary to discover
+ *           the capabilities in an OS specific way.  Such capabilities are
+ *           listed here when libpng has support for them and must be turned
+ *           ON by the application if present.
+ *
+ * SOFTWARE: sometimes software optimizations actually result in performance
+ *           decrease on some architectures or systems, or with some sets of
+ *           PNG images.  'Software' options allow such optimizations to be
+ *           selected at run time.
+ */
+#ifdef PNG_SET_OPTION_SUPPORTED
+#ifdef PNG_ARM_NEON_API_SUPPORTED
+#  define PNG_ARM_NEON   0 /* HARDWARE: ARM Neon SIMD instructions supported */
+#endif
+#define PNG_MAXIMUM_INFLATE_WINDOW 2 /* SOFTWARE: force maximum window */
+#define PNG_SKIP_sRGB_CHECK_PROFILE 4 /* SOFTWARE: Check ICC profile for sRGB */
+#define PNG_OPTION_NEXT  6 /* Next option - numbers must be even */
+
+/* Return values: NOTE: there are four values and 'off' is *not* zero */
+#define PNG_OPTION_UNSET   0 /* Unset - defaults to off */
+#define PNG_OPTION_INVALID 1 /* Option number out of range */
+#define PNG_OPTION_OFF     2
+#define PNG_OPTION_ON      3
+
+PNG_EXPORT(244, int, png_set_option, (png_structrp png_ptr, int option,
+   int onoff));
+#endif
+
+/*******************************************************************************
+ *  END OF HARDWARE AND SOFTWARE OPTIONS
+ ******************************************************************************/
+
+/* Maintainer: Put new public prototypes here ^, in libpng.3, and project
+ * defs, scripts/pnglibconf.h, and scripts/pnglibconf.h.prebuilt
+ */
+
 /* The last ordinal number (this is the *last* one already used; the next
 * one to use is one more than this.)  Maintainer, remember to add an entry to
 * scripts/symbols.def as well.
--- a/pngconf.h
+++ b/pngconf.h
@@ -1,9 +1,9 @@

 /* pngconf.h - machine configurable file for libpng
 *
- * libpng version 1.7.0beta52 - February 21, 2015
+ * libpng version 1.6.13beta04 - August 8, 2014
 *
- * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
@@ -22,6 +22,26 @@
 #ifndef PNGCONF_H
 #define PNGCONF_H

+/* To do: Do all of this in scripts/pnglibconf.dfa */
+#ifdef PNG_SAFE_LIMITS_SUPPORTED
+#  ifdef PNG_USER_WIDTH_MAX
+#    undef PNG_USER_WIDTH_MAX
+#    define PNG_USER_WIDTH_MAX 1000000L
+#  endif
+#  ifdef PNG_USER_HEIGHT_MAX
+#    undef PNG_USER_HEIGHT_MAX
+#    define PNG_USER_HEIGHT_MAX 1000000L
+#  endif
+#  ifdef PNG_USER_CHUNK_MALLOC_MAX
+#    undef PNG_USER_CHUNK_MALLOC_MAX
+#    define PNG_USER_CHUNK_MALLOC_MAX 4000000L
+#  endif
+#  ifdef PNG_USER_CHUNK_CACHE_MAX
+#    undef PNG_USER_CHUNK_CACHE_MAX
+#    define PNG_USER_CHUNK_CACHE_MAX 128
+#  endif
+#endif
+
 #ifndef PNG_BUILDING_SYMBOL_TABLE /* else includes may cause problems */

 /* From libpng 1.6.0 libpng requires an ANSI X3.159-1989 ("ISOC90") compliant C
@@ -218,6 +238,7 @@
 #      define PNGAPI _stdcall
 #    endif
 #  endif /* compiler/api */
+
  /* NOTE: PNGCBAPI always defaults to PNGCAPI. */

 #  if defined(PNGAPI) && !defined(PNG_USER_PRIVATEBUILD)
@@ -365,6 +386,7 @@
 #    ifndef PNG_RESTRICT
 #      define PNG_RESTRICT __restrict
 #    endif
+
 #  elif defined(__GNUC__)
 #    ifndef PNG_USE_RESULT
 #      define PNG_USE_RESULT __attribute__((__warn_unused_result__))
@@ -445,14 +467,6 @@
 #  define PNG_RESTRICT    /* The C99 "restrict" feature */
 #endif

-#ifndef PNG_FP_EXPORT     /* A floating point API. */
-#  ifdef PNG_FLOATING_POINT_SUPPORTED
-#     define PNG_FP_EXPORT(ordinal, type, name, args)\
-         PNG_EXPORT(ordinal, type, name, args);
-#  else                   /* No floating point APIs */
-#     define PNG_FP_EXPORT(ordinal, type, name, args)
-#  endif
-#endif
 #ifndef PNG_FP_EXPORT     /* A floating point API. */
 #  ifdef PNG_FLOATING_POINT_SUPPORTED
 #     define PNG_FP_EXPORT(ordinal, type, name, args)\
@@ -525,8 +539,6 @@

 /* Prior to 1.6.0 it was possible to disable the use of size_t, 1.6.0, however,
 * requires an ISOC90 compiler and relies on consistent behavior of sizeof.
- *
- * DEPRECATED: don't use these types, instead use size_t and ptrdiff_t.
 */
 typedef size_t png_size_t;
 typedef ptrdiff_t png_ptrdiff_t;
@@ -547,13 +559,13 @@ typedef ptrdiff_t png_ptrdiff_t;
 #  endif
 #endif

-/* png_alloc_size_t is guaranteed to be no smaller than size_t, and no
- * smaller than png_uint_32.  Casts from size_t or png_uint_32 to
+/* png_alloc_size_t is guaranteed to be no smaller than png_size_t, and no
+ * smaller than png_uint_32.  Casts from png_size_t or png_uint_32 to
 * png_alloc_size_t are not necessary; in fact, it is recommended not to use
 * them at all so that the compiler can complain when something turns out to be
 * problematic.
 *
- * Casts in the other direction (from png_alloc_size_t to size_t or
+ * Casts in the other direction (from png_alloc_size_t to png_size_t or
 * png_uint_32) should be explicitly applied; however, we do not expect to
 * encounter practical situations that require such conversions.
 *
@@ -563,7 +575,7 @@ typedef ptrdiff_t png_ptrdiff_t;
 #ifdef PNG_SMALL_SIZE_T
   typedef png_uint_32 png_alloc_size_t;
 #else
-   typedef size_t png_alloc_size_t;
+   typedef png_size_t png_alloc_size_t;
 #endif

 /* Prior to 1.6.0 libpng offered limited support for Microsoft C compiler
@@ -599,8 +611,8 @@ typedef char                  * png_charp;
 typedef const char            * png_const_charp;
 typedef png_fixed_point       * png_fixed_point_p;
 typedef const png_fixed_point * png_const_fixed_point_p;
-typedef size_t                * png_size_tp;
-typedef const size_t          * png_const_size_tp;
+typedef png_size_t            * png_size_tp;
+typedef const png_size_t      * png_const_size_tp;

 #ifdef PNG_STDIO_SUPPORTED
 typedef FILE            * png_FILE_p;
--- a/pngdebug.h
+++ b/pngdebug.h
@@ -1,11 +1,12 @@

 /* pngdebug.h - Debugging macros for libpng, also used in pngtest.c
 *
- * Last changed in libpng 1.6.8 [December 19, 2013]
 * Copyright (c) 1998-2013 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
+ * Last changed in libpng 1.6.8 [December 19, 2013]
+ *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
 * and license in png.h
--- a/pngerror.c
+++ b/pngerror.c
@@ -1,8 +1,8 @@

 /* pngerror.c - stub functions for i/o and memory allocation
 *
- * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.13 [(PENDING RELEASE)]
+ * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
@@ -27,7 +27,7 @@ static PNG_FUNCTION(void, png_default_error,PNGARG((png_const_structrp png_ptr,
 static void /* PRIVATE */
 png_default_warning PNGARG((png_const_structrp png_ptr,
   png_const_charp warning_message));
-#endif /* WARNINGS */
+#endif /* PNG_WARNINGS_SUPPORTED */

 /* This function is called whenever there is a fatal error.  This function
 * should not be changed.  If there is a need to handle errors differently,
@@ -43,8 +43,8 @@ png_error,(png_const_structrp png_ptr, png_const_charp error_message),
   char msg[16];
   if (png_ptr != NULL)
   {
-      if ((png_ptr->flags &
-         (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT)) != 0
+      if (png_ptr->flags&
+         (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))
      {
         if (*error_message == PNG_LITERAL_SHARP)
         {
@@ -54,7 +54,7 @@ png_error,(png_const_structrp png_ptr, png_const_charp error_message),
               if (error_message[offset] == ' ')
                  break;

-            if ((png_ptr->flags & PNG_FLAG_STRIP_ERROR_TEXT) != 0)
+            if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT)
            {
               int i;
               for (i = 0; i < offset - 1; i++)
@@ -69,7 +69,7 @@ png_error,(png_const_structrp png_ptr, png_const_charp error_message),

      else
      {
-         if ((png_ptr->flags & PNG_FLAG_STRIP_ERROR_TEXT) != 0)
+         if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT)
         {
            msg[0] = '0';
            msg[1] = '\0';
@@ -103,7 +103,7 @@ png_err,(png_const_structrp png_ptr),PNG_NORETURN)
      use the default handler, which will not return. */
   png_default_error(png_ptr, "");
 }
-#endif /* ERROR_TEXT */
+#endif /* PNG_ERROR_TEXT_SUPPORTED */

 /* Utility to safely appends strings to a buffer.  This never errors out so
 * error checking is not required in the caller.
@@ -152,7 +152,7 @@ png_format_number(png_const_charp start, png_charp end, int format,
         case PNG_NUMBER_FORMAT_fixed:
            /* Needs five digits (the fraction) */
            mincount = 5;
-            if (output != 0 || number % 10 != 0)
+            if (output || number % 10 != 0)
            {
               *--end = digits[number % 10];
               output = 1;
@@ -189,7 +189,7 @@ png_format_number(png_const_charp start, png_charp end, int format,
      ++count;

      /* Float a fixed number here: */
-      if ((format == PNG_NUMBER_FORMAT_fixed) && (count == 5) && (end > start))
+      if (format == PNG_NUMBER_FORMAT_fixed) if (count == 5) if (end > start)
      {
         /* End of the fraction, but maybe nothing was output?  In that case
          * drop the decimal point.  If the number is a true zero handle that
@@ -219,8 +219,8 @@ png_warning(png_const_structrp png_ptr, png_const_charp warning_message)
   if (png_ptr != NULL)
   {
 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
-   if ((png_ptr->flags &
-       (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT)) != 0)
+   if (png_ptr->flags&
+       (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))
 #endif
      {
         if (*warning_message == PNG_LITERAL_SHARP)
@@ -355,13 +355,13 @@ png_formatted_warning(png_const_structrp png_ptr, png_warning_parameters p,
    */
   png_warning(png_ptr, msg);
 }
-#endif /* WARNINGS */
+#endif /* PNG_WARNINGS_SUPPORTED */

 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
 void PNGAPI
 png_benign_error(png_const_structrp png_ptr, png_const_charp error_message)
 {
-   if ((png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN) != 0)
+   if (png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN)
   {
 #     ifdef PNG_READ_SUPPORTED
         if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 &&
@@ -391,7 +391,7 @@ png_benign_error(png_const_structrp png_ptr, png_const_charp error_message)
 void /* PRIVATE */
 png_app_warning(png_const_structrp png_ptr, png_const_charp error_message)
 {
-  if ((png_ptr->flags & PNG_FLAG_APP_WARNINGS_WARN) != 0)
+  if (png_ptr->flags & PNG_FLAG_APP_WARNINGS_WARN)
     png_warning(png_ptr, error_message);
  else
     png_error(png_ptr, error_message);
@@ -404,7 +404,7 @@ png_app_warning(png_const_structrp png_ptr, png_const_charp error_message)
 void /* PRIVATE */
 png_app_error(png_const_structrp png_ptr, png_const_charp error_message)
 {
-  if ((png_ptr->flags & PNG_FLAG_APP_ERRORS_WARN) != 0)
+  if (png_ptr->flags & PNG_FLAG_APP_ERRORS_WARN)
     png_warning(png_ptr, error_message);
  else
     png_error(png_ptr, error_message);
@@ -415,13 +415,13 @@ png_app_error(png_const_structrp png_ptr, png_const_charp error_message)
 }
 #endif /* BENIGN_ERRORS */

-#define PNG_MAX_ERROR_TEXT 196 /* Currently limited by profile_error in png.c */
+#define PNG_MAX_ERROR_TEXT 196 /* Currently limited be profile_error in png.c */
 #if defined(PNG_WARNINGS_SUPPORTED) || \
   (defined(PNG_READ_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED))
 /* These utilities are used internally to build an error message that relates
 * to the current chunk.  The chunk name comes from png_ptr->chunk_name,
- * which is used to prefix the message.  The message is limited in length
- * to 63 bytes. The name characters are output as hex digits wrapped in []
+ * this is used to prefix the message.  The message is limited in length
+ * to 63 bytes, the name characters are output as hex digits wrapped in []
 * if the character is invalid.
 */
 #define isnonalpha(c) ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
@@ -442,7 +442,7 @@ png_format_buffer(png_const_structrp png_ptr, png_charp buffer, png_const_charp
      int c = (int)(chunk_name >> ishift) & 0xff;

      ishift -= 8;
-      if (isnonalpha(c) != 0)
+      if (isnonalpha(c))
      {
         buffer[iout++] = PNG_LITERAL_LEFT_SQUARE_BRACKET;
         buffer[iout++] = png_digit[(c & 0xf0) >> 4];
@@ -473,7 +473,7 @@ png_format_buffer(png_const_structrp png_ptr, png_charp buffer, png_const_charp
      buffer[iout] = '\0';
   }
 }
-#endif /* WARNINGS || ERROR_TEXT */
+#endif /* PNG_WARNINGS_SUPPORTED || PNG_ERROR_TEXT_SUPPORTED */

 #if defined(PNG_READ_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED)
 PNG_FUNCTION(void,PNGAPI
@@ -490,7 +490,7 @@ png_chunk_error,(png_const_structrp png_ptr, png_const_charp error_message),
      png_error(png_ptr, msg);
   }
 }
-#endif /* READ && ERROR_TEXT */
+#endif /* PNG_READ_SUPPORTED && PNG_ERROR_TEXT_SUPPORTED */

 #ifdef PNG_WARNINGS_SUPPORTED
 void PNGAPI
@@ -506,7 +506,7 @@ png_chunk_warning(png_const_structrp png_ptr, png_const_charp warning_message)
      png_warning(png_ptr, msg);
   }
 }
-#endif /* WARNINGS */
+#endif /* PNG_WARNINGS_SUPPORTED */

 #ifdef PNG_READ_SUPPORTED
 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
@@ -514,7 +514,7 @@ void PNGAPI
 png_chunk_benign_error(png_const_structrp png_ptr, png_const_charp
    error_message)
 {
-   if ((png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN) != 0)
+   if (png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN)
      png_chunk_warning(png_ptr, error_message);

   else
@@ -525,7 +525,7 @@ png_chunk_benign_error(png_const_structrp png_ptr, png_const_charp
 #  endif
 }
 #endif
-#endif /* READ */
+#endif /* PNG_READ_SUPPORTED */

 void /* PRIVATE */
 png_chunk_report(png_const_structrp png_ptr, png_const_charp message, int error)
@@ -538,7 +538,7 @@ png_chunk_report(png_const_structrp png_ptr, png_const_charp message, int error)
    * unconditionally does the right thing.
    */
 #  if defined(PNG_READ_SUPPORTED) && defined(PNG_WRITE_SUPPORTED)
-      if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
+      if (png_ptr->mode & PNG_IS_READ_STRUCT)
 #  endif

 #  ifdef PNG_READ_SUPPORTED
@@ -552,7 +552,7 @@ png_chunk_report(png_const_structrp png_ptr, png_const_charp message, int error)
 #  endif

 #  if defined(PNG_READ_SUPPORTED) && defined(PNG_WRITE_SUPPORTED)
-      else if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
+      else if (!(png_ptr->mode & PNG_IS_READ_STRUCT))
 #  endif

 #  ifdef PNG_WRITE_SUPPORTED
@@ -567,13 +567,7 @@ png_chunk_report(png_const_structrp png_ptr, png_const_charp message, int error)
 }

 #ifdef PNG_ERROR_TEXT_SUPPORTED
-
-#if defined(PNG_FLOATING_POINT_SUPPORTED) && \
-   (defined(PNG_gAMA_SUPPORTED) || defined(PNG_cHRM_SUPPORTED) || \
-   defined(PNG_sCAL_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) || \
-   defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)) || \
-   (defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) &&\
-   defined(PNG_sCAL_SUPPORTED))
+#ifdef PNG_FLOATING_POINT_SUPPORTED
 PNG_FUNCTION(void,
 png_fixed_error,(png_const_structrp png_ptr, png_const_charp name),PNG_NORETURN)
 {
@@ -583,12 +577,11 @@ png_fixed_error,(png_const_structrp png_ptr, png_const_charp name),PNG_NORETURN)
   char msg[fixed_message_ln+PNG_MAX_ERROR_TEXT];
   memcpy(msg, fixed_message, fixed_message_ln);
   iin = 0;
-   if (name != NULL)
-      while (iin < (PNG_MAX_ERROR_TEXT-1) && name[iin] != 0)
-      {
-         msg[fixed_message_ln + iin] = name[iin];
-         ++iin;
-      }
+   if (name != NULL) while (iin < (PNG_MAX_ERROR_TEXT-1) && name[iin] != 0)
+   {
+      msg[fixed_message_ln + iin] = name[iin];
+      ++iin;
+   }
   msg[fixed_message_ln + iin] = 0;
   png_error(png_ptr, msg);
 }
@@ -764,8 +757,7 @@ PNG_FUNCTION(void,PNGAPI
 png_longjmp,(png_const_structrp png_ptr, int val),PNG_NORETURN)
 {
 #ifdef PNG_SETJMP_SUPPORTED
-   if (png_ptr != NULL && png_ptr->longjmp_fn != NULL &&
-       png_ptr->jmp_buf_ptr != NULL)
+   if (png_ptr && png_ptr->longjmp_fn && png_ptr->jmp_buf_ptr)
      png_ptr->longjmp_fn(*png_ptr->jmp_buf_ptr, val);
 #else
   PNG_UNUSED(png_ptr)
@@ -776,13 +768,9 @@ png_longjmp,(png_const_structrp png_ptr, int val),PNG_NORETURN)
    * choice is to terminate the whole process (or maybe the thread); to do
    * this the ANSI-C abort() function is used unless a different method is 
    * implemented by overriding the default configuration setting for
-    * PNG_ABORT (see scripts/pnglibconf.dfa).
-    *
-    * API change: prior to 1.7.0 PNG_ABORT was invoked as a function type macro
-    * with no arguments 'PNG_ABORT();', in 1.7.0 this is changed to a simple
-    * macro that is defined in the configuration.
+    * PNG_ABORT().
    */
-   PNG_ABORT
+   PNG_ABORT();
 }

 #ifdef PNG_WARNINGS_SUPPORTED
@@ -834,7 +822,7 @@ png_default_warning(png_const_structrp png_ptr, png_const_charp warning_message)
 #endif
   PNG_UNUSED(png_ptr) /* Make compiler happy */
 }
-#endif /* WARNINGS */
+#endif /* PNG_WARNINGS_SUPPORTED */

 /* This function is called when the application wants to use another method
 * of handling errors and warnings.  Note that the error function MUST NOT
@@ -969,5 +957,5 @@ png_safe_execute(png_imagep image_in, int (*function)(png_voidp), png_voidp arg)

   return result;
 }
-#endif /* SIMPLIFIED READ || SIMPLIFIED_WRITE */
-#endif /* READ || WRITE */
+#endif /* SIMPLIFIED READ/WRITE */
+#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
--- a/pngget.c
+++ b/pngget.c
@@ -1,8 +1,8 @@

 /* pngget.c - retrieval of values from info struct
 *
- * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.11 [June 5, 2014]
+ * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
@@ -116,8 +116,7 @@ png_get_x_pixels_per_meter(png_const_structrp png_ptr, png_const_inforp
   info_ptr)
 {
 #ifdef PNG_pHYs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_pHYs) != 0)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
      {
         png_debug1(1, "in %s retrieval function",
             "png_get_x_pixels_per_meter");
@@ -138,8 +137,7 @@ png_get_y_pixels_per_meter(png_const_structrp png_ptr, png_const_inforp
    info_ptr)
 {
 #ifdef PNG_pHYs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_pHYs) != 0)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
   {
      png_debug1(1, "in %s retrieval function",
          "png_get_y_pixels_per_meter");
@@ -159,8 +157,7 @@ png_uint_32 PNGAPI
 png_get_pixels_per_meter(png_const_structrp png_ptr, png_const_inforp info_ptr)
 {
 #ifdef PNG_pHYs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_pHYs) != 0)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
   {
      png_debug1(1, "in %s retrieval function", "png_get_pixels_per_meter");

@@ -182,8 +179,7 @@ png_get_pixel_aspect_ratio(png_const_structrp png_ptr, png_const_inforp
   info_ptr)
 {
 #ifdef PNG_READ_pHYs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_pHYs) != 0)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
   {
      png_debug1(1, "in %s retrieval function", "png_get_aspect_ratio");

@@ -206,11 +202,10 @@ png_get_pixel_aspect_ratio_fixed(png_const_structrp png_ptr,
    png_const_inforp info_ptr)
 {
 #ifdef PNG_READ_pHYs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_pHYs) != 0 &&
-       info_ptr->x_pixels_per_unit > 0 && info_ptr->y_pixels_per_unit > 0 &&
-       info_ptr->x_pixels_per_unit <= PNG_UINT_31_MAX &&
-       info_ptr->y_pixels_per_unit <= PNG_UINT_31_MAX)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs)
+       && info_ptr->x_pixels_per_unit > 0 && info_ptr->y_pixels_per_unit > 0
+       && info_ptr->x_pixels_per_unit <= PNG_UINT_31_MAX
+       && info_ptr->y_pixels_per_unit <= PNG_UINT_31_MAX)
   {
      png_fixed_point res;

@@ -220,7 +215,7 @@ png_get_pixel_aspect_ratio_fixed(png_const_structrp png_ptr,
       * range of 0..2^31-1; otherwise the cast might overflow.
       */
      if (png_muldiv(&res, (png_int_32)info_ptr->y_pixels_per_unit, PNG_FP_1,
-          (png_int_32)info_ptr->x_pixels_per_unit) != 0)
+          (png_int_32)info_ptr->x_pixels_per_unit))
         return res;
   }
 #else
@@ -236,8 +231,7 @@ png_int_32 PNGAPI
 png_get_x_offset_microns(png_const_structrp png_ptr, png_const_inforp info_ptr)
 {
 #ifdef PNG_oFFs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_oFFs) != 0)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs))
   {
      png_debug1(1, "in %s retrieval function", "png_get_x_offset_microns");

@@ -256,8 +250,7 @@ png_int_32 PNGAPI
 png_get_y_offset_microns(png_const_structrp png_ptr, png_const_inforp info_ptr)
 {
 #ifdef PNG_oFFs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_oFFs) != 0)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs))
   {
      png_debug1(1, "in %s retrieval function", "png_get_y_offset_microns");

@@ -276,8 +269,7 @@ png_int_32 PNGAPI
 png_get_x_offset_pixels(png_const_structrp png_ptr, png_const_inforp info_ptr)
 {
 #ifdef PNG_oFFs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_oFFs) != 0)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs))
   {
      png_debug1(1, "in %s retrieval function", "png_get_x_offset_pixels");

@@ -296,8 +288,7 @@ png_int_32 PNGAPI
 png_get_y_offset_pixels(png_const_structrp png_ptr, png_const_inforp info_ptr)
 {
 #ifdef PNG_oFFs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_oFFs) != 0)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs))
   {
      png_debug1(1, "in %s retrieval function", "png_get_y_offset_pixels");

@@ -337,7 +328,7 @@ ppi_from_ppm(png_uint_32 ppm)
    */
   png_fixed_point result;
   if (ppm <= PNG_UINT_31_MAX && png_muldiv(&result, (png_int_32)ppm, 127,
-       5000) != 0)
+       5000))
      return result;

   /* Overflow. */
@@ -423,8 +414,7 @@ png_get_pHYs_dpi(png_const_structrp png_ptr, png_const_inforp info_ptr,
 {
   png_uint_32 retval = 0;

-   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_pHYs) != 0)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
   {
      png_debug1(1, "in %s retrieval function", "pHYs");

@@ -455,12 +445,12 @@ png_get_pHYs_dpi(png_const_structrp png_ptr, png_const_inforp info_ptr,

   return (retval);
 }
-#endif /* pHYs */
-#endif  /* INCH_CONVERSIONS */
+#endif /* PNG_pHYs_SUPPORTED */
+#endif  /* PNG_INCH_CONVERSIONS_SUPPORTED */

 /* png_get_channels really belongs in here, too, but it's been around longer */

-#endif  /* EASY_ACCESS */
+#endif  /* PNG_EASY_ACCESS_SUPPORTED */


 png_byte PNGAPI
@@ -488,9 +478,8 @@ png_uint_32 PNGAPI
 png_get_bKGD(png_const_structrp png_ptr, png_inforp info_ptr,
   png_color_16p *background)
 {
-   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_bKGD) != 0 &&
-       background != NULL)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD)
+       && background != NULL)
   {
      png_debug1(1, "in %s retrieval function", "bKGD");

@@ -520,7 +509,7 @@ png_get_cHRM(png_const_structrp png_ptr, png_const_inforp info_ptr,
    * consistent.
    */
   if (png_ptr != NULL && info_ptr != NULL &&
-      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS))
   {
      png_debug1(1, "in %s retrieval function", "cHRM");

@@ -561,7 +550,7 @@ png_get_cHRM_XYZ(png_const_structrp png_ptr, png_const_inforp info_ptr,
   double *blue_Z)
 {
   if (png_ptr != NULL && info_ptr != NULL &&
-      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS))
   {
      png_debug1(1, "in %s retrieval function", "cHRM_XYZ(float)");

@@ -609,7 +598,7 @@ png_get_cHRM_XYZ_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
    png_fixed_point *int_blue_Z)
 {
   if (png_ptr != NULL && info_ptr != NULL &&
-      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS))
   {
      png_debug1(1, "in %s retrieval function", "cHRM_XYZ");

@@ -646,7 +635,7 @@ png_get_cHRM_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
   png_debug1(1, "in %s retrieval function", "cHRM");

   if (png_ptr != NULL && info_ptr != NULL &&
-      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS))
   {
      if (white_x != NULL)
         *white_x = info_ptr->colorspace.end_points_xy.whitex;
@@ -681,7 +670,7 @@ png_get_gAMA_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
   png_debug1(1, "in %s retrieval function", "gAMA");

   if (png_ptr != NULL && info_ptr != NULL &&
-      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) != 0 &&
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) &&
      file_gamma != NULL)
   {
      *file_gamma = info_ptr->colorspace.gamma;
@@ -700,7 +689,7 @@ png_get_gAMA(png_const_structrp png_ptr, png_const_inforp info_ptr,
   png_debug1(1, "in %s retrieval function", "gAMA(float)");

   if (png_ptr != NULL && info_ptr != NULL &&
-      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) != 0 &&
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) &&
      file_gamma != NULL)
   {
      *file_gamma = png_float(png_ptr, info_ptr->colorspace.gamma,
@@ -720,8 +709,8 @@ png_get_sRGB(png_const_structrp png_ptr, png_const_inforp info_ptr,
 {
   png_debug1(1, "in %s retrieval function", "sRGB");

-   if (png_ptr != NULL && info_ptr != NULL &&
-      (info_ptr->valid & PNG_INFO_sRGB) != 0 && file_srgb_intent != NULL)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_sRGB)
+       && file_srgb_intent != NULL)
   {
      *file_srgb_intent = info_ptr->colorspace.rendering_intent;
      return (PNG_INFO_sRGB);
@@ -739,10 +728,9 @@ png_get_iCCP(png_const_structrp png_ptr, png_inforp info_ptr,
 {
   png_debug1(1, "in %s retrieval function", "iCCP");

-   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_iCCP) != 0 &&
-       name != NULL && compression_type != NULL && profile != NULL &&
-           proflen != NULL)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_iCCP)
+       && name != NULL && compression_type != NULL && profile != NULL &&
+		 proflen != NULL)
   {
      *name = info_ptr->iccp_name;
      *profile = info_ptr->iccp_profile;
@@ -780,8 +768,8 @@ png_get_hIST(png_const_structrp png_ptr, png_inforp info_ptr,
 {
   png_debug1(1, "in %s retrieval function", "hIST");

-   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_hIST) != 0 && hist != NULL)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST)
+       && hist != NULL)
   {
      *hist = info_ptr->hist;
      return (PNG_INFO_hIST);
@@ -799,20 +787,14 @@ png_get_IHDR(png_const_structrp png_ptr, png_const_inforp info_ptr,
 {
   png_debug1(1, "in %s retrieval function", "IHDR");

-   if (png_ptr == NULL || info_ptr == NULL)
+   if (png_ptr == NULL || info_ptr == NULL || width == NULL ||
+       height == NULL || bit_depth == NULL || color_type == NULL)
      return (0);

-   if (width != NULL)
-       *width = info_ptr->width;
-
-   if (height != NULL)
-       *height = info_ptr->height;
-
-   if (bit_depth != NULL)
-       *bit_depth = info_ptr->bit_depth;
-
-   if (color_type != NULL)
-       *color_type = info_ptr->color_type;
+   *width = info_ptr->width;
+   *height = info_ptr->height;
+   *bit_depth = info_ptr->bit_depth;
+   *color_type = info_ptr->color_type;

   if (compression_type != NULL)
      *compression_type = info_ptr->compression_type;
@@ -842,9 +824,8 @@ png_get_oFFs(png_const_structrp png_ptr, png_const_inforp info_ptr,
 {
   png_debug1(1, "in %s retrieval function", "oFFs");

-   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_oFFs) != 0 &&
-       offset_x != NULL && offset_y != NULL && unit_type != NULL)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs)
+       && offset_x != NULL && offset_y != NULL && unit_type != NULL)
   {
      *offset_x = info_ptr->x_offset;
      *offset_y = info_ptr->y_offset;
@@ -864,9 +845,8 @@ png_get_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,
 {
   png_debug1(1, "in %s retrieval function", "pCAL");

-   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_pCAL) != 0 &&
-       purpose != NULL && X0 != NULL && X1 != NULL && type != NULL &&
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL)
+       && purpose != NULL && X0 != NULL && X1 != NULL && type != NULL &&
       nparams != NULL && units != NULL && params != NULL)
   {
      *purpose = info_ptr->pcal_purpose;
@@ -884,14 +864,15 @@ png_get_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,
 #endif

 #ifdef PNG_sCAL_SUPPORTED
-#  ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
-#     ifdef PNG_FIXED_POINT_SUPPORTED
+#  ifdef PNG_FIXED_POINT_SUPPORTED
+#    if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || \
+         defined(PNG_FLOATING_POINT_SUPPORTED)
 png_uint_32 PNGAPI
 png_get_sCAL_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
    int *unit, png_fixed_point *width, png_fixed_point *height)
 {
   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_sCAL) != 0)
+       (info_ptr->valid & PNG_INFO_sCAL))
   {
      *unit = info_ptr->scal_unit;
      /*TODO: make this work without FP support; the API is currently eliminated
@@ -906,15 +887,15 @@ png_get_sCAL_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,

   return(0);
 }
-#     endif /* FIXED_POINT */
-
-#     ifdef PNG_FLOATING_POINT_SUPPORTED
+#    endif /* FLOATING_ARITHMETIC */
+#  endif /* FIXED_POINT */
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
 png_uint_32 PNGAPI
 png_get_sCAL(png_const_structrp png_ptr, png_const_inforp info_ptr,
    int *unit, double *width, double *height)
 {
   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_sCAL) != 0)
+       (info_ptr->valid & PNG_INFO_sCAL))
   {
      *unit = info_ptr->scal_unit;
      *width = atof(info_ptr->scal_s_width);
@@ -924,15 +905,13 @@ png_get_sCAL(png_const_structrp png_ptr, png_const_inforp info_ptr,

   return(0);
 }
-#     endif /* FLOATING POINT */
-#  endif /* FLOATING_ARITHMETIC */
-
+#  endif /* FLOATING POINT */
 png_uint_32 PNGAPI
 png_get_sCAL_s(png_const_structrp png_ptr, png_const_inforp info_ptr,
    int *unit, png_charpp width, png_charpp height)
 {
   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_sCAL) != 0)
+       (info_ptr->valid & PNG_INFO_sCAL))
   {
      *unit = info_ptr->scal_unit;
      *width = info_ptr->scal_s_width;
@@ -954,7 +933,7 @@ png_get_pHYs(png_const_structrp png_ptr, png_const_inforp info_ptr,
   png_debug1(1, "in %s retrieval function", "pHYs");

   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_pHYs) != 0)
+       (info_ptr->valid & PNG_INFO_pHYs))
   {
      if (res_x != NULL)
      {
@@ -985,8 +964,8 @@ png_get_PLTE(png_const_structrp png_ptr, png_inforp info_ptr,
 {
   png_debug1(1, "in %s retrieval function", "PLTE");

-   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_PLTE) != 0 && palette != NULL)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_PLTE)
+       && palette != NULL)
   {
      *palette = info_ptr->palette;
      *num_palette = info_ptr->num_palette;
@@ -1004,8 +983,8 @@ png_get_sBIT(png_const_structrp png_ptr, png_inforp info_ptr,
 {
   png_debug1(1, "in %s retrieval function", "sBIT");

-   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_sBIT) != 0 && sig_bit != NULL)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT)
+       && sig_bit != NULL)
   {
      *sig_bit = &(info_ptr->sig_bit);
      return (PNG_INFO_sBIT);
@@ -1048,8 +1027,8 @@ png_get_tIME(png_const_structrp png_ptr, png_inforp info_ptr,
 {
   png_debug1(1, "in %s retrieval function", "tIME");

-   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_tIME) != 0 && mod_time != NULL)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME)
+       && mod_time != NULL)
   {
      *mod_time = &(info_ptr->mod_time);
      return (PNG_INFO_tIME);
@@ -1065,8 +1044,7 @@ png_get_tRNS(png_const_structrp png_ptr, png_inforp info_ptr,
    png_bytep *trans_alpha, int *num_trans, png_color_16p *trans_color)
 {
   png_uint_32 retval = 0;
-   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_tRNS) != 0)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS))
   {
      png_debug1(1, "in %s retrieval function", "tRNS");

@@ -1142,21 +1120,21 @@ png_get_compression_buffer_size(png_const_structrp png_ptr)
   if (png_ptr == NULL)
      return 0;

-#ifdef PNG_WRITE_SUPPORTED
-      if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
-#endif
+#  ifdef PNG_WRITE_SUPPORTED
+      if (png_ptr->mode & PNG_IS_READ_STRUCT)
+#  endif
   {
-#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+#     ifdef PNG_SEQUENTIAL_READ_SUPPORTED
         return png_ptr->IDAT_read_size;
-#else
+#     else
         return PNG_IDAT_READ_SIZE;
-#endif
+#     endif
   }

-#ifdef PNG_WRITE_SUPPORTED
+#  ifdef PNG_WRITE_SUPPORTED
      else
         return png_ptr->zbuffer_size;
-#endif
+#  endif
 }

 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
@@ -1187,7 +1165,7 @@ png_get_chunk_malloc_max (png_const_structrp png_ptr)
 {
   return (png_ptr ? png_ptr->user_chunk_malloc_max : 0);
 }
-#endif /* SET_USER_LIMITS */
+#endif /* ?PNG_SET_USER_LIMITS_SUPPORTED */

 /* These functions were added to libpng 1.4.0 */
 #ifdef PNG_IO_STATE_SUPPORTED
@@ -1202,12 +1180,12 @@ png_get_io_chunk_type (png_const_structrp png_ptr)
 {
   return png_ptr->chunk_name;
 }
-#endif /* IO_STATE */
+#endif /* ?PNG_IO_STATE_SUPPORTED */

 #ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
 #  ifdef PNG_GET_PALETTE_MAX_SUPPORTED
 int PNGAPI
-png_get_palette_max(png_const_structrp png_ptr, png_const_inforp info_ptr)
+png_get_palette_max(png_const_structp png_ptr, png_const_infop info_ptr)
 {
   if (png_ptr != NULL && info_ptr != NULL)
      return png_ptr->num_palette_max;
@@ -1217,4 +1195,4 @@ png_get_palette_max(png_const_structrp png_ptr, png_const_inforp info_ptr)
 #  endif
 #endif

-#endif /* READ || WRITE */
+#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
--- a/pnginfo.h
+++ b/pnginfo.h
@@ -1,11 +1,12 @@

 /* pnginfo.h - header file for PNG reference library
 *
- * Last changed in libpng 1.6.1 [March 28, 2013]
 * Copyright (c) 1998-2013 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
+ * Last changed in libpng 1.6.1 [March 28, 2013]
+ *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
 * and license in png.h
@@ -120,7 +121,7 @@ struct png_info_def
   int num_text; /* number of comments read or comments to write */
   int max_text; /* current size of text array */
   png_textp text; /* array of comments read or comments to write */
-#endif /* TEXT */
+#endif /* PNG_TEXT_SUPPORTED */

 #ifdef PNG_tIME_SUPPORTED
   /* The tIME chunk holds the last time the displayed image data was
--- a/pngmem.c
+++ b/pngmem.c
@@ -1,8 +1,8 @@

 /* pngmem.c - stub functions for memory allocation
 *
- * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.8 [December 19, 2013]
+ * Copyright (c) 1998-2013 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
@@ -126,7 +126,7 @@ png_malloc_array,(png_const_structrp png_ptr, int nelements,
 }

 PNG_FUNCTION(png_voidp /* PRIVATE */,
-png_realloc_array,(png_structrp png_ptr, png_const_voidp old_array,
+png_realloc_array,(png_const_structrp png_ptr, png_const_voidp old_array,
   int old_elements, int add_elements, size_t element_size),PNG_ALLOCATED)
 {
   /* These are internal errors: */
@@ -157,15 +157,6 @@ png_realloc_array,(png_structrp png_ptr, png_const_voidp old_array,
      }
   }

-#ifdef PNG_READ_SUPPORTED
-# ifdef PNG_USER_LIMITS_SUPPORTED
-   /* The potential overflow case.  Set the cache counter so libpng will
-    * not make any more attempts
-    */
-   png_ptr->user_chunk_cache_max = 2;
-# endif
-#endif
-
   return NULL; /* error */
 }
 #endif /* TEXT || sPLT || STORE_UNKNOWN_CHUNKS */
@@ -185,11 +176,31 @@ png_malloc,(png_const_structrp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
   ret = png_malloc_base(png_ptr, size);

   if (ret == NULL)
-       png_error(png_ptr, "Out of memory");
+       png_error(png_ptr, "Out of memory"); /* 'm' means png_malloc */

   return ret;
 }

+#ifdef PNG_USER_MEM_SUPPORTED
+PNG_FUNCTION(png_voidp,PNGAPI
+png_malloc_default,(png_const_structrp png_ptr, png_alloc_size_t size),
+   PNG_ALLOCATED PNG_DEPRECATED)
+{
+   png_voidp ret;
+
+   if (png_ptr == NULL)
+      return NULL;
+
+   /* Passing 'NULL' here bypasses the application provided memory handler. */
+   ret = png_malloc_base(NULL/*use malloc*/, size);
+
+   if (ret == NULL)
+      png_error(png_ptr, "Out of Memory"); /* 'M' means png_malloc_default */
+
+   return ret;
+}
+#endif /* PNG_USER_MEM_SUPPORTED */
+
 /* This function was added at libpng version 1.2.3.  The png_malloc_warn()
 * function will issue a png_warning and return NULL instead of issuing a
 * png_error, if it fails to allocate the requested memory.
@@ -225,8 +236,17 @@ png_free(png_const_structrp png_ptr, png_voidp ptr)
      png_ptr->free_fn(png_constcast(png_structrp,png_ptr), ptr);

   else
-#endif /* USER_MEM */
-      free(ptr);
+      png_free_default(png_ptr, ptr);
+}
+
+PNG_FUNCTION(void,PNGAPI
+png_free_default,(png_const_structrp png_ptr, png_voidp ptr),PNG_DEPRECATED)
+{
+   if (png_ptr == NULL || ptr == NULL)
+      return;
+#endif /* PNG_USER_MEM_SUPPORTED */
+
+   free(ptr);
 }

 #ifdef PNG_USER_MEM_SUPPORTED
@@ -257,5 +277,5 @@ png_get_mem_ptr(png_const_structrp png_ptr)

   return png_ptr->mem_ptr;
 }
-#endif /* USER_MEM */
-#endif /* READ || WRITE */
+#endif /* PNG_USER_MEM_SUPPORTED */
+#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
--- a/pngpread.c
+++ b/pngpread.c
@@ -1,8 +1,8 @@

 /* pngpread.c - read a png file in push mode
 *
- * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.11 [June 5, 2014]
+ * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
@@ -26,13 +26,6 @@
 #define PNG_READ_iTXt_MODE  7
 #define PNG_ERROR_MODE      8

-#define PNG_PUSH_SAVE_BUFFER_IF_FULL \
-if (png_ptr->push_length + 4 > png_ptr->buffer_size) \
-   { png_push_save_buffer(png_ptr); return; }
-#define PNG_PUSH_SAVE_BUFFER_IF_LT(N) \
-if (png_ptr->buffer_size < N) \
-   { png_push_save_buffer(png_ptr); return; }
-
 void PNGAPI
 png_process_data(png_structrp png_ptr, png_inforp info_ptr,
    png_bytep buffer, png_size_t buffer_size)
@@ -53,7 +46,7 @@ png_process_data_pause(png_structrp png_ptr, int save)
 {
   if (png_ptr != NULL)
   {
-      /* It's easiest for the caller if we do the save; then the caller doesn't
+      /* It's easiest for the caller if we do the save, then the caller doesn't
       * have to supply the same data again:
       */
      if (save != 0)
@@ -192,22 +185,27 @@ void /* PRIVATE */
 png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 {
   png_uint_32 chunk_name;
-#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
   int keep; /* unknown handling method */
 #endif

-   /* First we make sure we have enough data for the 4-byte chunk name
-    * and the 4-byte chunk length before proceeding with decoding the
+   /* First we make sure we have enough data for the 4 byte chunk name
+    * and the 4 byte chunk length before proceeding with decoding the
    * chunk data.  To fully decode each of these chunks, we also make
-    * sure we have enough data in the buffer for the 4-byte CRC at the
+    * sure we have enough data in the buffer for the 4 byte CRC at the
    * end of every chunk (except IDAT, which is handled separately).
    */
-   if ((png_ptr->mode & PNG_HAVE_CHUNK_HEADER) == 0)
+   if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
   {
      png_byte chunk_length[4];
      png_byte chunk_tag[4];

-      PNG_PUSH_SAVE_BUFFER_IF_LT(8)
+      if (png_ptr->buffer_size < 8)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
      png_push_fill_buffer(png_ptr, chunk_length, 4);
      png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
      png_reset_crc(png_ptr);
@@ -221,29 +219,29 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)

   if (chunk_name == png_IDAT)
   {
-      if ((png_ptr->mode & PNG_AFTER_IDAT) != 0)
+      if (png_ptr->mode & PNG_AFTER_IDAT)
         png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;

      /* If we reach an IDAT chunk, this means we have read all of the
       * header chunks, and we can start reading the image (or if this
       * is called after the image has been read - we have an error).
       */
-      if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      if (!(png_ptr->mode & PNG_HAVE_IHDR))
         png_error(png_ptr, "Missing IHDR before IDAT");

      else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
-          (png_ptr->mode & PNG_HAVE_PLTE) == 0)
+          !(png_ptr->mode & PNG_HAVE_PLTE))
         png_error(png_ptr, "Missing PLTE before IDAT");

      png_ptr->mode |= PNG_HAVE_IDAT;
      png_ptr->process_mode = PNG_READ_IDAT_MODE;

-      if ((png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) == 0)
+      if (!(png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
         if (png_ptr->push_length == 0)
            return;

-      if ((png_ptr->mode & PNG_AFTER_IDAT) != 0)
-         png_benign_error(png_ptr, "Too many IDATs found[p]");
+      if (png_ptr->mode & PNG_AFTER_IDAT)
+         png_benign_error(png_ptr, "Too many IDATs found");
   }

   if (chunk_name == png_IHDR)
@@ -251,23 +249,38 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
      if (png_ptr->push_length != 13)
         png_error(png_ptr, "Invalid IHDR length");

-      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
      png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
   }

   else if (chunk_name == png_IEND)
   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
      png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);

      png_ptr->process_mode = PNG_READ_DONE_MODE;
      png_push_have_end(png_ptr, info_ptr);
   }

-#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
   else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0)
   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
      png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length, keep);

      if (chunk_name == png_PLTE)
@@ -277,7 +290,11 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)

   else if (chunk_name == png_PLTE)
   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
      png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -296,7 +313,12 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_gAMA_SUPPORTED
   else if (png_ptr->chunk_name == png_gAMA)
   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
      png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -304,7 +326,12 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_sBIT_SUPPORTED
   else if (png_ptr->chunk_name == png_sBIT)
   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
      png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -312,7 +339,12 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_cHRM_SUPPORTED
   else if (png_ptr->chunk_name == png_cHRM)
   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
      png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -320,7 +352,12 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_sRGB_SUPPORTED
   else if (chunk_name == png_sRGB)
   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
      png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -328,7 +365,12 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_iCCP_SUPPORTED
   else if (png_ptr->chunk_name == png_iCCP)
   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
      png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -336,7 +378,12 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_sPLT_SUPPORTED
   else if (chunk_name == png_sPLT)
   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
      png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -344,7 +391,12 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_tRNS_SUPPORTED
   else if (chunk_name == png_tRNS)
   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
      png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -352,7 +404,12 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_bKGD_SUPPORTED
   else if (chunk_name == png_bKGD)
   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
      png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -360,7 +417,12 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_hIST_SUPPORTED
   else if (chunk_name == png_hIST)
   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
      png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -368,7 +430,12 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_pHYs_SUPPORTED
   else if (chunk_name == png_pHYs)
   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
      png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -376,7 +443,12 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_oFFs_SUPPORTED
   else if (chunk_name == png_oFFs)
   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
      png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length);
   }
 #endif
@@ -384,7 +456,12 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_pCAL_SUPPORTED
   else if (chunk_name == png_pCAL)
   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
      png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -392,7 +469,12 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_sCAL_SUPPORTED
   else if (chunk_name == png_sCAL)
   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
      png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -400,7 +482,12 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_tIME_SUPPORTED
   else if (chunk_name == png_tIME)
   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
      png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -408,7 +495,12 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_tEXt_SUPPORTED
   else if (chunk_name == png_tEXt)
   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
      png_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -416,7 +508,12 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_zTXt_SUPPORTED
   else if (chunk_name == png_zTXt)
   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
      png_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -424,14 +521,23 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_iTXt_SUPPORTED
   else if (chunk_name == png_iTXt)
   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
      png_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
   }
 #endif

   else
   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
      png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length,
         PNG_HANDLE_CHUNK_AS_DEFAULT);
   }
@@ -449,7 +555,7 @@ png_push_crc_skip(png_structrp png_ptr, png_uint_32 skip)
 void /* PRIVATE */
 png_push_crc_finish(png_structrp png_ptr)
 {
-   if (png_ptr->skip_length != 0 && png_ptr->save_buffer_size != 0)
+   if (png_ptr->skip_length && png_ptr->save_buffer_size)
   {
      png_size_t save_size = png_ptr->save_buffer_size;
      png_uint_32 skip_length = png_ptr->skip_length;
@@ -473,7 +579,7 @@ png_push_crc_finish(png_structrp png_ptr)
      png_ptr->save_buffer_size -= save_size;
      png_ptr->save_buffer_ptr += save_size;
   }
-   if (png_ptr->skip_length != 0 && png_ptr->current_buffer_size != 0)
+   if (png_ptr->skip_length && png_ptr->current_buffer_size)
   {
      png_size_t save_size = png_ptr->current_buffer_size;
      png_uint_32 skip_length = png_ptr->skip_length;
@@ -494,9 +600,14 @@ png_push_crc_finish(png_structrp png_ptr)
      png_ptr->current_buffer_size -= save_size;
      png_ptr->current_buffer_ptr += save_size;
   }
-   if (png_ptr->skip_length == 0)
+   if (!png_ptr->skip_length)
   {
-      PNG_PUSH_SAVE_BUFFER_IF_LT(4)
+      if (png_ptr->buffer_size < 4)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
      png_crc_finish(png_ptr, 0);
      png_ptr->process_mode = PNG_READ_CHUNK_MODE;
   }
@@ -511,7 +622,7 @@ png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
      return;

   ptr = buffer;
-   if (png_ptr->save_buffer_size != 0)
+   if (png_ptr->save_buffer_size)
   {
      png_size_t save_size;

@@ -528,7 +639,7 @@ png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
      png_ptr->save_buffer_size -= save_size;
      png_ptr->save_buffer_ptr += save_size;
   }
-   if (length != 0 && png_ptr->current_buffer_size != 0)
+   if (length && png_ptr->current_buffer_size)
   {
      png_size_t save_size;

@@ -548,7 +659,7 @@ png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
 void /* PRIVATE */
 png_push_save_buffer(png_structrp png_ptr)
 {
-   if (png_ptr->save_buffer_size != 0)
+   if (png_ptr->save_buffer_size)
   {
      if (png_ptr->save_buffer_ptr != png_ptr->save_buffer)
      {
@@ -584,13 +695,11 @@ png_push_save_buffer(png_structrp png_ptr)
      if (png_ptr->save_buffer == NULL)
      {
         png_free(png_ptr, old_buffer);
-         old_buffer = NULL;
         png_error(png_ptr, "Insufficient memory for save_buffer");
      }

      memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size);
      png_free(png_ptr, old_buffer);
-      old_buffer = NULL;
      png_ptr->save_buffer_max = new_max;
   }
   if (png_ptr->current_buffer_size)
@@ -617,13 +726,18 @@ png_push_restore_buffer(png_structrp png_ptr, png_bytep buffer,
 void /* PRIVATE */
 png_push_read_IDAT(png_structrp png_ptr)
 {
-   if ((png_ptr->mode & PNG_HAVE_CHUNK_HEADER) == 0)
+   if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
   {
      png_byte chunk_length[4];
      png_byte chunk_tag[4];

      /* TODO: this code can be commoned up with the same code in push_read */
-      PNG_PUSH_SAVE_BUFFER_IF_LT(8)
+      if (png_ptr->buffer_size < 8)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
      png_push_fill_buffer(png_ptr, chunk_length, 4);
      png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
      png_reset_crc(png_ptr);
@@ -635,7 +749,7 @@ png_push_read_IDAT(png_structrp png_ptr)
      {
         png_ptr->process_mode = PNG_READ_CHUNK_MODE;

-         if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
+         if (!(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED))
            png_error(png_ptr, "Not enough compressed data");

         return;
@@ -644,7 +758,7 @@ png_push_read_IDAT(png_structrp png_ptr)
      png_ptr->idat_size = png_ptr->push_length;
   }

-   if (png_ptr->idat_size != 0 && png_ptr->save_buffer_size != 0)
+   if (png_ptr->idat_size && png_ptr->save_buffer_size)
   {
      png_size_t save_size = png_ptr->save_buffer_size;
      png_uint_32 idat_size = png_ptr->idat_size;
@@ -671,7 +785,7 @@ png_push_read_IDAT(png_structrp png_ptr)
      png_ptr->save_buffer_ptr += save_size;
   }

-   if (png_ptr->idat_size != 0 && png_ptr->current_buffer_size != 0)
+   if (png_ptr->idat_size && png_ptr->current_buffer_size)
   {
      png_size_t save_size = png_ptr->current_buffer_size;
      png_uint_32 idat_size = png_ptr->idat_size;
@@ -696,9 +810,14 @@ png_push_read_IDAT(png_structrp png_ptr)
      png_ptr->current_buffer_size -= save_size;
      png_ptr->current_buffer_ptr += save_size;
   }
-   if (png_ptr->idat_size == 0)
+   if (!png_ptr->idat_size)
   {
-      PNG_PUSH_SAVE_BUFFER_IF_LT(4)
+      if (png_ptr->buffer_size < 4)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
      png_crc_finish(png_ptr, 0);
      png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
      png_ptr->mode |= PNG_AFTER_IDAT;
@@ -726,7 +845,7 @@ png_process_IDAT_data(png_structrp png_ptr, png_bytep buffer,
    * or the stream marked as finished.
    */
   while (png_ptr->zstream.avail_in > 0 &&
-      (png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
+      !(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED))
   {
      int ret;

@@ -843,7 +962,7 @@ png_push_process_row(png_structrp png_ptr)
   memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1);

 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
-   if (png_ptr->transformations != 0)
+   if (png_ptr->transformations)
      png_do_read_transformations(png_ptr, &row_info);
 #endif

@@ -861,8 +980,7 @@ png_push_process_row(png_structrp png_ptr)

 #ifdef PNG_READ_INTERLACING_SUPPORTED
   /* Expand interlaced rows to full size */
-   if (png_ptr->interlaced != 0 &&
-       (png_ptr->transformations & PNG_INTERLACE) != 0)
+   if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
   {
      if (png_ptr->pass < 6)
         png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
@@ -1036,7 +1154,6 @@ png_push_process_row(png_structrp png_ptr)
      }
   }
   else
-#endif
   {
      png_push_have_row(png_ptr, png_ptr->row_buf + 1);
      png_read_push_finish_row(png_ptr);
@@ -1046,7 +1163,6 @@ png_push_process_row(png_structrp png_ptr)
 void /* PRIVATE */
 png_read_push_finish_row(png_structrp png_ptr)
 {
-#ifdef PNG_READ_INTERLACING_SUPPORTED
   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */

   /* Start of interlace block */
@@ -1071,8 +1187,7 @@ png_read_push_finish_row(png_structrp png_ptr)
   if (png_ptr->row_number < png_ptr->num_rows)
      return;

-#ifdef PNG_READ_INTERLACING_SUPPORTED
-   if (png_ptr->interlaced != 0)
+   if (png_ptr->interlaced)
   {
      png_ptr->row_number = 0;
      memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
@@ -1096,7 +1211,7 @@ png_read_push_finish_row(png_structrp png_ptr)
             png_pass_start[png_ptr->pass]) /
             png_pass_inc[png_ptr->pass];

-         if ((png_ptr->transformations & PNG_INTERLACE) != 0)
+         if (png_ptr->transformations & PNG_INTERLACE)
            break;

         png_ptr->num_rows = (png_ptr->height +
@@ -1106,7 +1221,6 @@ png_read_push_finish_row(png_structrp png_ptr)

      } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0);
   }
-#endif /* READ_INTERLACING */
 }

 void /* PRIVATE */
@@ -1131,7 +1245,6 @@ png_push_have_row(png_structrp png_ptr, png_bytep row)
         (int)png_ptr->pass);
 }

-#ifdef PNG_READ_INTERLACING_SUPPORTED
 void PNGAPI
 png_progressive_combine_row(png_const_structrp png_ptr, png_bytep old_row,
    png_const_bytep new_row)
@@ -1146,7 +1259,6 @@ png_progressive_combine_row(png_const_structrp png_ptr, png_bytep old_row,
   if (new_row != NULL)
      png_combine_row(png_ptr, old_row, 1/*blocky display*/);
 }
-#endif /* READ_INTERLACING */

 void PNGAPI
 png_set_progressive_read_fn(png_structrp png_ptr, png_voidp progressive_ptr,
@@ -1171,4 +1283,4 @@ png_get_progressive_ptr(png_const_structrp png_ptr)

   return png_ptr->io_ptr;
 }
-#endif /* PROGRESSIVE_READ */
+#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
--- a/pngpriv.h
+++ b/pngpriv.h
@@ -1,11 +1,13 @@

 /* pngpriv.h - private declarations for use inside libpng
 *
- * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
+ * Last changed in libpng 1.6.10 [March 6, 1014]]
+ *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
 * and license in png.h
@@ -38,17 +40,10 @@
 #define _POSIX_SOURCE 1 /* Just the POSIX 1003.1 and C89 APIs */

 #ifndef PNG_VERSION_INFO_ONLY
-/* Keep standard libraries at the top of this file */
-
 /* Standard library headers not required by png.h: */
 #  include <stdlib.h>
 #  include <string.h>
-
-/* For headers only required with some build configurations see the lines after
- * pnglibconf.h is included!
- */
-
-#endif /* VERSION_INFO_ONLY */
+#endif

 #define PNGLIB_BUILD /*libpng is being built, not used*/

@@ -93,36 +88,6 @@
 #  endif
 #endif

-#ifndef PNG_VERSION_INFO_ONLY
-/* Additional standard libaries required in certain cases, put only standard
- * ANSI-C89 headers here.  If not available, or non-functional, the problem
- * should be fixed by writing a wrapper for the header and the file on your
- * include path.
- */
-#if defined(PNG_sCAL_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED)
-   /* png.c requires the following ANSI-C constants if the conversion of
-    * floating point to ASCII is implemented therein:
-    *
-    *  DBL_MIN_10_EXP Minimum negative integer such that 10^integer is a
-    *                 normalized (double) value.
-    *  DBL_DIG  Maximum number of decimal digits (can be set to any constant)
-    *  DBL_MIN  Smallest normalized fp number (can be set to an arbitrary value)
-    *  DBL_MAX  Maximum floating point number (can be set to an arbitrary value)
-    */
-#  include <float.h>
-#endif /* sCAL && FLOATING_POINT */
-
-#if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) ||\
-   defined(PNG_FLOATING_POINT_SUPPORTED)
-   /* ANSI-C90 math functions are required.  Full compliance with the standard
-    * is probably not a requirement, but the functions must exist and be
-    * declared in <math.h>
-    */
-#  include <math.h>
-#endif /* FLOATING_ARITHMETIC || FLOATING_POINT */
-
-#endif /* VERSION_INFO_ONLY */
-
 /* Compile time options.
 * =====================
 * In a multi-arch build the compiler may compile the code several times for the
@@ -154,8 +119,12 @@
    * PNG_ARM_NEON_OPT is set in CPPFLAGS (to >0) then arm/arm_init.c will fail
    * to compile with an appropriate #error if ALIGNED_MEMORY has been turned
    * off.
+    *
+    * Note that gcc-4.9 defines __ARM_NEON instead of __ARM_NEON__, so we
+    * check both variants.
    */
-#  if defined(__ARM_NEON__) && defined(PNG_ALIGNED_MEMORY_SUPPORTED)
+#  if (defined(__ARM_NEON__) || defined(__ARM_NEON)) && \
+   defined(PNG_ALIGNED_MEMORY_SUPPORTED)
 #     define PNG_ARM_NEON_OPT 2
 #  else
 #     define PNG_ARM_NEON_OPT 0
@@ -183,7 +152,7 @@
    * libpng implementation list for incorporation in the next minor release.
    */
 #  ifndef PNG_ARM_NEON_IMPLEMENTATION
-#     ifdef __ARM_NEON__
+#     if defined(__ARM_NEON__) || defined(__ARM_NEON)
 #        if defined(__clang__)
            /* At present it is unknown by the libpng developers which versions
             * of clang support the intrinsics, however some or perhaps all
@@ -322,9 +291,6 @@
 #  endif
 #endif

-/* Include png.h here to get the version info and other macros, pngstruct.h and
- * pnginfo.h are included later under the protection of !PNG_VERSION_INFO_ONLY
- */
 #include "png.h"

 /* pngconf.h does not set PNG_DLL_EXPORT unless it is required, so: */
@@ -332,22 +298,48 @@
 #  define PNG_DLL_EXPORT
 #endif

-/* asserts are turned off in release code, but are in even in release candidates
- * because often system builders only check future libpng releases when a
- * release candidate is available.
- */
-#if PNG_LIBPNG_BUILD_BASE_TYPE == PNG_LIBPNG_BUILD_STABLE
-#  define NDEBUG
-#endif
-#ifndef PNG_VERSION_INFO_ONLY
-#  include <assert.h>
-#endif
-
 /* SECURITY and SAFETY:
 *
- * libpng is built with support for internal limits on image dimensions and
- * memory usage.  These are documented in scripts/pnglibconf.dfa of the
- * source and recorded in the machine generated header file pnglibconf.h.
+ * By default libpng is built without any internal limits on image size,
+ * individual heap (png_malloc) allocations or the total amount of memory used.
+ * If PNG_SAFE_LIMITS_SUPPORTED is defined, however, the limits below are used
+ * (unless individually overridden).  These limits are believed to be fairly
+ * safe, but builders of secure systems should verify the values against the
+ * real system capabilities.
+ */
+#ifdef PNG_SAFE_LIMITS_SUPPORTED
+   /* 'safe' limits */
+#  ifndef PNG_USER_WIDTH_MAX
+#     define PNG_USER_WIDTH_MAX 1000000
+#  endif
+#  ifndef PNG_USER_HEIGHT_MAX
+#     define PNG_USER_HEIGHT_MAX 1000000
+#  endif
+#  ifndef PNG_USER_CHUNK_CACHE_MAX
+#     define PNG_USER_CHUNK_CACHE_MAX 128
+#  endif
+#  ifndef PNG_USER_CHUNK_MALLOC_MAX
+#     define PNG_USER_CHUNK_MALLOC_MAX 8000000
+#  endif
+#else
+   /* values for no limits */
+#  ifndef PNG_USER_WIDTH_MAX
+#     define PNG_USER_WIDTH_MAX 0x7fffffff
+#  endif
+#  ifndef PNG_USER_HEIGHT_MAX
+#     define PNG_USER_HEIGHT_MAX 0x7fffffff
+#  endif
+#  ifndef PNG_USER_CHUNK_CACHE_MAX
+#     define PNG_USER_CHUNK_CACHE_MAX 0
+#  endif
+#  ifndef PNG_USER_CHUNK_MALLOC_MAX
+#     define PNG_USER_CHUNK_MALLOC_MAX 0
+#  endif
+#endif
+
+/* Moved to pngpriv.h at libpng-1.5.0 */
+/* NOTE: some of these may have been used in external applications as
+ * these definitions were exposed in pngconf.h prior to 1.5.
 */

 /* If you are running on a machine where you cannot allocate more
@@ -429,6 +421,67 @@
 #  define PNGFAPI /* PRIVATE */
 #endif

+#ifndef PNG_VERSION_INFO_ONLY
+/* Other defines specific to compilers can go here.  Try to keep
+ * them inside an appropriate ifdef/endif pair for portability.
+ */
+#if defined(PNG_FLOATING_POINT_SUPPORTED) ||\
+    defined(PNG_FLOATING_ARITHMETIC_SUPPORTED)
+   /* png.c requires the following ANSI-C constants if the conversion of
+    * floating point to ASCII is implemented therein:
+    *
+    *  DBL_DIG  Maximum number of decimal digits (can be set to any constant)
+    *  DBL_MIN  Smallest normalized fp number (can be set to an arbitrary value)
+    *  DBL_MAX  Maximum floating point number (can be set to an arbitrary value)
+    */
+#  include <float.h>
+
+#  if (defined(__MWERKS__) && defined(macintosh)) || defined(applec) || \
+    defined(THINK_C) || defined(__SC__) || defined(TARGET_OS_MAC)
+     /* We need to check that <math.h> hasn't already been included earlier
+      * as it seems it doesn't agree with <fp.h>, yet we should really use
+      * <fp.h> if possible.
+      */
+#    if !defined(__MATH_H__) && !defined(__MATH_H) && !defined(__cmath__)
+#      include <fp.h>
+#    endif
+#  else
+#    include <math.h>
+#  endif
+#  if defined(_AMIGA) && defined(__SASC) && defined(_M68881)
+     /* Amiga SAS/C: We must include builtin FPU functions when compiling using
+      * MATH=68881
+      */
+#    include <m68881.h>
+#  endif
+#endif
+
+/* This provides the non-ANSI (far) memory allocation routines. */
+#if defined(__TURBOC__) && defined(__MSDOS__)
+#  include <mem.h>
+#  include <alloc.h>
+#endif
+
+#if defined(WIN32) || defined(_Windows) || defined(_WINDOWS) || \
+    defined(_WIN32) || defined(__WIN32__)
+#  include <windows.h>  /* defines _WINDOWS_ macro */
+#endif
+#endif /* PNG_VERSION_INFO_ONLY */
+
+/* Moved here around 1.5.0beta36 from pngconf.h */
+/* Users may want to use these so they are not private.  Any library
+ * functions that are passed far data must be model-independent.
+ */
+
+/* Memory model/platform independent fns */
+#ifndef PNG_ABORT
+#  ifdef _WINDOWS_
+#    define PNG_ABORT() ExitProcess(0)
+#  else
+#    define PNG_ABORT() abort()
+#  endif
+#endif
+
 /* These macros may need to be architecture dependent. */
 #define PNG_ALIGN_NONE   0 /* do not use data alignment */
 #define PNG_ALIGN_ALWAYS 1 /* assume unaligned accesses are OK */
@@ -497,7 +550,7 @@
 #define PNG_HAVE_CHUNK_HEADER      0x100
 #define PNG_WROTE_tIME             0x200
 #define PNG_WROTE_INFO_BEFORE_PLTE 0x400
-                   /*              0x800 (unused) */
+#define PNG_BACKGROUND_IS_GRAY     0x800
 #define PNG_HAVE_PNG_SIGNATURE    0x1000
 #define PNG_HAVE_CHUNK_AFTER_IDAT 0x2000 /* Have another chunk after IDAT */
                   /*             0x4000 (unused) */
@@ -511,10 +564,10 @@
 #define PNG_SWAP_BYTES          0x0010
 #define PNG_INVERT_MONO         0x0020
 #define PNG_QUANTIZE            0x0040
-#define PNG_COMPOSE             0x0080 /* Was PNG_BACKGROUND */
-                       /*       0x0100 unused */
-#define PNG_EXPAND_16           0x0200 /* Added to libpng 1.5.2 */
-#define PNG_16_TO_8             0x0400 /* Becomes 'chop' in 1.5.4 */
+#define PNG_COMPOSE             0x0080     /* Was PNG_BACKGROUND */
+#define PNG_BACKGROUND_EXPAND   0x0100
+#define PNG_EXPAND_16           0x0200     /* Added to libpng 1.5.2 */
+#define PNG_16_TO_8             0x0400     /* Becomes 'chop' in 1.5.4 */
 #define PNG_RGBA                0x0800
 #define PNG_EXPAND              0x1000
 #define PNG_GAMMA               0x2000
@@ -529,13 +582,13 @@
 #define PNG_RGB_TO_GRAY_WARN  0x400000
 #define PNG_RGB_TO_GRAY       0x600000 /* two bits, RGB_TO_GRAY_ERR|WARN */
 #define PNG_ENCODE_ALPHA      0x800000 /* Added to libpng-1.5.4 */
-#define PNG_ADD_ALPHA        0x1000000 /* Added to libpng-1.2.7 */
-#define PNG_EXPAND_tRNS      0x2000000 /* Added to libpng-1.2.9 */
-#define PNG_SCALE_16_TO_8    0x4000000 /* Added to libpng-1.5.4 */
-                       /*    0x8000000 unused */
-                       /*   0x10000000 unused */
-                       /*   0x20000000 unused */
-                       /*   0x40000000 unused */
+#define PNG_ADD_ALPHA         0x1000000 /* Added to libpng-1.2.7 */
+#define PNG_EXPAND_tRNS       0x2000000 /* Added to libpng-1.2.9 */
+#define PNG_SCALE_16_TO_8     0x4000000 /* Added to libpng-1.5.4 */
+                       /*   0x8000000 unused */
+                       /*  0x10000000 unused */
+                       /*  0x20000000 unused */
+                       /*  0x40000000 unused */
 /* Flags for png_create_struct */
 #define PNG_STRUCT_PNG   0x0001
 #define PNG_STRUCT_INFO  0x0002
@@ -568,8 +621,8 @@
 #define PNG_FLAG_BENIGN_ERRORS_WARN     0x100000 /* Added to libpng-1.4.0 */
 #define PNG_FLAG_APP_WARNINGS_WARN      0x200000 /* Added to libpng-1.6.0 */
 #define PNG_FLAG_APP_ERRORS_WARN        0x400000 /* Added to libpng-1.6.0 */
-#define PNG_FLAG_BACKGROUND_IS_GRAY     0x800000
-#define PNG_FLAG_BACKGROUND_EXPAND     0x1000000
+                                  /*    0x800000    unused */
+                                  /*   0x1000000    unused */
                                  /*   0x2000000    unused */
                                  /*   0x4000000    unused */
                                  /*   0x8000000    unused */
@@ -592,16 +645,6 @@
   abs((int)((c1).green) - (int)((c2).green)) + \
   abs((int)((c1).blue) - (int)((c2).blue)))

-#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
-   defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
-/* See below for the definitions of the tables used in these macros */
-#define PNG_sRGB_FROM_LINEAR(linear) ((png_byte)((png_sRGB_base[(linear)>>15] +\
-   ((((linear)&0x7fff)*png_sRGB_delta[(linear)>>15])>>12)) >> 8))
-   /* Given a value 'linear' in the range 0..255*65535 calculate the 8-bit sRGB
-    * encoded value with maximum error 0.646365.  Note that the input is not a
-    * 16-bit value; it has been multiplied by 255! */
-#endif /* PNG_SIMPLIFIED_READ/WRITE */
-
 /* Added to libpng-1.6.0: scale a 16-bit value in the range 0..65535 to 0..255
 * by dividing by 257 *with rounding*.  This macro is exact for the given range.
 * See the discourse in pngrtran.c png_do_scale_16_to_8.  The values in the
@@ -666,6 +709,98 @@
 */
 #endif

+/* Constants for known chunk types.  If you need to add a chunk, define the name
+ * here.  For historical reasons these constants have the form png_<name>; i.e.
+ * the prefix is lower case.  Please use decimal values as the parameters to
+ * match the ISO PNG specification and to avoid relying on the C locale
+ * interpretation of character values.
+ *
+ * Prior to 1.5.6 these constants were strings, as of 1.5.6 png_uint_32 values
+ * are computed and a new macro (PNG_STRING_FROM_CHUNK) added to allow a string
+ * to be generated if required.
+ *
+ * PNG_32b correctly produces a value shifted by up to 24 bits, even on
+ * architectures where (int) is only 16 bits.
+ */
+#define PNG_32b(b,s) ((png_uint_32)(b) << (s))
+#define PNG_U32(b1,b2,b3,b4) \
+   (PNG_32b(b1,24) | PNG_32b(b2,16) | PNG_32b(b3,8) | PNG_32b(b4,0))
+
+/* Constants for known chunk types.
+ *
+ * MAINTAINERS: If you need to add a chunk, define the name here.
+ * For historical reasons these constants have the form png_<name>; i.e.
+ * the prefix is lower case.  Please use decimal values as the parameters to
+ * match the ISO PNG specification and to avoid relying on the C locale
+ * interpretation of character values.  Please keep the list sorted.
+ *
+ * Notice that PNG_U32 is used to define a 32-bit value for the 4 byte chunk
+ * type.  In fact the specification does not express chunk types this way,
+ * however using a 32-bit value means that the chunk type can be read from the
+ * stream using exactly the same code as used for a 32-bit unsigned value and
+ * can be examined far more efficiently (using one arithmetic compare).
+ *
+ * Prior to 1.5.6 the chunk type constants were expressed as C strings.  The
+ * libpng API still uses strings for 'unknown' chunks and a macro,
+ * PNG_STRING_FROM_CHUNK, allows a string to be generated if required.  Notice
+ * that for portable code numeric values must still be used; the string "IHDR"
+ * is not portable and neither is PNG_U32('I', 'H', 'D', 'R').
+ *
+ * In 1.7.0 the definitions will be made public in png.h to avoid having to
+ * duplicate the same definitions in application code.
+ */
+#define png_IDAT PNG_U32( 73,  68,  65,  84)
+#define png_IEND PNG_U32( 73,  69,  78,  68)
+#define png_IHDR PNG_U32( 73,  72,  68,  82)
+#define png_PLTE PNG_U32( 80,  76,  84,  69)
+#define png_bKGD PNG_U32( 98,  75,  71,  68)
+#define png_cHRM PNG_U32( 99,  72,  82,  77)
+#define png_fRAc PNG_U32(102,  82,  65,  99) /* registered, not defined */
+#define png_gAMA PNG_U32(103,  65,  77,  65)
+#define png_gIFg PNG_U32(103,  73,  70, 103)
+#define png_gIFt PNG_U32(103,  73,  70, 116) /* deprecated */
+#define png_gIFx PNG_U32(103,  73,  70, 120)
+#define png_hIST PNG_U32(104,  73,  83,  84)
+#define png_iCCP PNG_U32(105,  67,  67,  80)
+#define png_iTXt PNG_U32(105,  84,  88, 116)
+#define png_oFFs PNG_U32(111,  70,  70, 115)
+#define png_pCAL PNG_U32(112,  67,  65,  76)
+#define png_pHYs PNG_U32(112,  72,  89, 115)
+#define png_sBIT PNG_U32(115,  66,  73,  84)
+#define png_sCAL PNG_U32(115,  67,  65,  76)
+#define png_sPLT PNG_U32(115,  80,  76,  84)
+#define png_sRGB PNG_U32(115,  82,  71,  66)
+#define png_sTER PNG_U32(115,  84,  69,  82)
+#define png_tEXt PNG_U32(116,  69,  88, 116)
+#define png_tIME PNG_U32(116,  73,  77,  69)
+#define png_tRNS PNG_U32(116,  82,  78,  83)
+#define png_zTXt PNG_U32(122,  84,  88, 116)
+
+/* The following will work on (signed char*) strings, whereas the get_uint_32
+ * macro will fail on top-bit-set values because of the sign extension.
+ */
+#define PNG_CHUNK_FROM_STRING(s)\
+   PNG_U32(0xff&(s)[0], 0xff&(s)[1], 0xff&(s)[2], 0xff&(s)[3])
+
+/* This uses (char), not (png_byte) to avoid warnings on systems where (char) is
+ * signed and the argument is a (char[])  This macro will fail miserably on
+ * systems where (char) is more than 8 bits.
+ */
+#define PNG_STRING_FROM_CHUNK(s,c)\
+   (void)(((char*)(s))[0]=(char)((c)>>24), ((char*)(s))[1]=(char)((c)>>16),\
+   ((char*)(s))[2]=(char)((c)>>8), ((char*)(s))[3]=(char)((c)))
+
+/* Do the same but terminate with a null character. */
+#define PNG_CSTRING_FROM_CHUNK(s,c)\
+   (void)(PNG_STRING_FROM_CHUNK(s,c), ((char*)(s))[4] = 0)
+
+/* Test on flag values as defined in the spec (section 5.4): */
+#define PNG_CHUNK_ANCILLARY(c)   (1 & ((c) >> 29))
+#define PNG_CHUNK_CRITICAL(c)     (!PNG_CHUNK_ANCILLARY(c))
+#define PNG_CHUNK_PRIVATE(c)      (1 & ((c) >> 21))
+#define PNG_CHUNK_RESERVED(c)     (1 & ((c) >> 13))
+#define PNG_CHUNK_SAFE_TO_COPY(c) (1 & ((c) >>  5))
+
 /* Gamma values (new at libpng-1.5.4): */
 #define PNG_GAMMA_MAC_OLD 151724  /* Assume '1.8' is really 2.2/1.45! */
 #define PNG_GAMMA_MAC_INVERSE 65909
@@ -714,6 +849,12 @@ PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_table, [256]);

 PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_base, [512]);
 PNG_INTERNAL_DATA(const png_byte, png_sRGB_delta, [512]);
+
+#define PNG_sRGB_FROM_LINEAR(linear) ((png_byte)((png_sRGB_base[(linear)>>15] +\
+   ((((linear)&0x7fff)*png_sRGB_delta[(linear)>>15])>>12)) >> 8))
+   /* Given a value 'linear' in the range 0..255*65535 calculate the 8-bit sRGB
+    * encoded value with maximum error 0.646365.  Note that the input is not a
+    * 16-bit value; it has been multiplied by 255! */
 #endif /* PNG_SIMPLIFIED_READ/WRITE */


@@ -742,16 +883,6 @@ PNG_INTERNAL_FUNCTION(void,png_free_buffer_list,(png_structrp png_ptr,
   /* Free the buffer list used by the compressed write code. */
 #endif

-#ifdef PNG_WRITE_FILTER_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_write_alloc_filter_row_buffers,
-   (png_structrp png_ptr, int filters),PNG_EMPTY);
-   /* Allocate pixel row buffers to cache filtered rows while testing candidate
-    * filters.
-    * TODO: avoid this, only one spare row buffer (at most) is required, this
-    * wastes a lot of memory for large images.
-    */
-#endif
-
 #if defined(PNG_FLOATING_POINT_SUPPORTED) && \
   !defined(PNG_FIXED_POINT_MACRO_SUPPORTED) && \
   (defined(PNG_gAMA_SUPPORTED) || defined(PNG_cHRM_SUPPORTED) || \
@@ -779,7 +910,7 @@ PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_base,(png_const_structrp png_ptr,
 #if defined(PNG_TEXT_SUPPORTED) || defined(PNG_sPLT_SUPPORTED) ||\
   defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED)
 /* Internal array allocator, outputs no error or warning messages on failure,
- * just returns NULL.
+ * just returns NULL.  
 */
 PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_array,(png_const_structrp png_ptr,
   int nelements, size_t element_size),PNG_ALLOCATED);
@@ -788,7 +919,7 @@ PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_array,(png_const_structrp png_ptr,
 * also memsets the new elements to 0 and copies the old elements.  The old
 * array is not freed or altered.
 */
-PNG_INTERNAL_FUNCTION(png_voidp,png_realloc_array,(png_structrp png_ptr,
+PNG_INTERNAL_FUNCTION(png_voidp,png_realloc_array,(png_const_structrp png_ptr,
   png_const_voidp array, int old_elements, int add_elements,
   size_t element_size),PNG_ALLOCATED);
 #endif /* text, sPLT or unknown chunks */
@@ -959,7 +1090,7 @@ PNG_INTERNAL_FUNCTION(void,png_write_tEXt,(png_structrp png_ptr,

 #ifdef PNG_WRITE_zTXt_SUPPORTED
 PNG_INTERNAL_FUNCTION(void,png_write_zTXt,(png_structrp png_ptr, png_const_charp
-    key, png_const_charp text, int compression),PNG_EMPTY);
+    key, png_const_charp text, png_size_t text_len, int compression),PNG_EMPTY);
 #endif

 #ifdef PNG_WRITE_iTXt_SUPPORTED
@@ -969,7 +1100,7 @@ PNG_INTERNAL_FUNCTION(void,png_write_iTXt,(png_structrp png_ptr,
 #endif

 #ifdef PNG_TEXT_SUPPORTED  /* Added at version 1.0.14 and 1.2.4 */
-PNG_INTERNAL_FUNCTION(int,png_set_text_2,(png_structrp png_ptr,
+PNG_INTERNAL_FUNCTION(int,png_set_text_2,(png_const_structrp png_ptr,
    png_inforp info_ptr, png_const_textp text_ptr, int num_text),PNG_EMPTY);
 #endif

@@ -1098,7 +1229,7 @@ PNG_INTERNAL_FUNCTION(void,png_read_finish_IDAT,(png_structrp png_ptr),
 PNG_INTERNAL_FUNCTION(void,png_read_finish_row,(png_structrp png_ptr),
   PNG_EMPTY);
   /* Finish a row while reading, dealing with interlacing passes, etc. */
-#endif /* SEQUENTIAL_READ */
+#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */

 /* Initialize the row buffers, etc. */
 PNG_INTERNAL_FUNCTION(void,png_read_start_row,(png_structrp png_ptr),PNG_EMPTY);
@@ -1174,7 +1305,7 @@ PNG_INTERNAL_FUNCTION(void,png_handle_hIST,(png_structrp png_ptr,
 #ifdef PNG_READ_iCCP_SUPPORTED
 PNG_INTERNAL_FUNCTION(void,png_handle_iCCP,(png_structrp png_ptr,
    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
-#endif /* READ_iCCP */
+#endif /* PNG_READ_iCCP_SUPPORTED */

 #ifdef PNG_READ_iTXt_SUPPORTED
 PNG_INTERNAL_FUNCTION(void,png_handle_iTXt,(png_structrp png_ptr,
@@ -1209,7 +1340,7 @@ PNG_INTERNAL_FUNCTION(void,png_handle_sCAL,(png_structrp png_ptr,
 #ifdef PNG_READ_sPLT_SUPPORTED
 PNG_INTERNAL_FUNCTION(void,png_handle_sPLT,(png_structrp png_ptr,
    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
-#endif /* READ_sPLT */
+#endif /* PNG_READ_sPLT_SUPPORTED */

 #ifdef PNG_READ_sRGB_SUPPORTED
 PNG_INTERNAL_FUNCTION(void,png_handle_sRGB,(png_structrp png_ptr,
@@ -1323,7 +1454,7 @@ PNG_INTERNAL_FUNCTION(void,png_push_read_iTXt,(png_structrp png_ptr,
    png_inforp info_ptr),PNG_EMPTY);
 #  endif

-#endif /* PROGRESSIVE_READ */
+#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */

 /* Added at libpng version 1.6.0 */
 #ifdef PNG_GAMMA_SUPPORTED
@@ -1723,7 +1854,7 @@ PNG_INTERNAL_FUNCTION(png_byte,png_gamma_8bit_correct,(unsigned int value,
   png_fixed_point gamma_value),PNG_EMPTY);
 PNG_INTERNAL_FUNCTION(void,png_destroy_gamma_table,(png_structrp png_ptr),
   PNG_EMPTY);
-PNG_INTERNAL_FUNCTION(void,png_build_gamma_tables,(png_structrp png_ptr,
+PNG_INTERNAL_FUNCTION(void,png_build_gamma_table,(png_structrp png_ptr,
   int bit_depth),PNG_EMPTY);
 #endif

@@ -1789,7 +1920,7 @@ PNG_INTERNAL_FUNCTION(void, png_image_free, (png_imagep image), PNG_EMPTY);
 * the generic code is used.
 */
 #ifdef PNG_FILTER_OPTIMIZATIONS
-PNG_INTERNAL_FUNCTION(void, PNG_FILTER_OPTIMIZATIONS, (png_structrp png_ptr,
+PNG_INTERNAL_FUNCTION(void, PNG_FILTER_OPTIMIZATIONS, (png_structp png_ptr,
   unsigned int bpp), PNG_EMPTY);
   /* Just declare the optimization that will be used */
 #else
--- a/pngread.c
+++ b/pngread.c
@@ -1,8 +1,8 @@

 /* pngread.c - read a PNG file
 *
- * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.11 [June 5, 2014]
+ * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
@@ -44,7 +44,7 @@ png_create_read_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
 {
   png_structp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
      error_fn, warn_fn, mem_ptr, malloc_fn, free_fn);
-#endif /* USER_MEM */
+#endif /* PNG_USER_MEM_SUPPORTED */

   if (png_ptr != NULL)
   {
@@ -113,20 +113,20 @@ png_read_info(png_structrp png_ptr, png_inforp info_ptr)
       */
      if (chunk_name == png_IDAT)
      {
-         if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+         if (!(png_ptr->mode & PNG_HAVE_IHDR))
            png_chunk_error(png_ptr, "Missing IHDR before IDAT");

         else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
-             (png_ptr->mode & PNG_HAVE_PLTE) == 0)
+             !(png_ptr->mode & PNG_HAVE_PLTE))
            png_chunk_error(png_ptr, "Missing PLTE before IDAT");

-         else if ((png_ptr->mode & PNG_AFTER_IDAT) != 0)
-            png_chunk_benign_error(png_ptr, "Too many IDATs found[s]");
+         else if (png_ptr->mode & PNG_AFTER_IDAT)
+            png_chunk_benign_error(png_ptr, "Too many IDATs found");

         png_ptr->mode |= PNG_HAVE_IDAT;
      }

-      else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+      else if (png_ptr->mode & PNG_HAVE_IDAT)
         png_ptr->mode |= PNG_AFTER_IDAT;

      /* This should be a binary subdivision search or a hash for
@@ -252,7 +252,7 @@ png_read_info(png_structrp png_ptr, png_inforp info_ptr)
            PNG_HANDLE_CHUNK_AS_DEFAULT);
   }
 }
-#endif /* SEQUENTIAL_READ */
+#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */

 /* Optional call to update the users info_ptr structure */
 void PNGAPI
@@ -302,7 +302,7 @@ png_start_read_image(png_structrp png_ptr)
            "png_start_read_image/png_read_update_info: duplicate call");
   }
 }
-#endif /* SEQUENTIAL_READ */
+#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */

 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
 #ifdef PNG_MNG_FEATURES_SUPPORTED
@@ -315,7 +315,7 @@ png_do_read_intrapixel(png_row_infop row_info, png_bytep row)
   png_debug(1, "in png_do_read_intrapixel");

   if (
-       (row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
+       (row_info->color_type & PNG_COLOR_MASK_COLOR))
   {
      int bytes_per_pixel;
      png_uint_32 row_width = row_info->width;
@@ -369,7 +369,7 @@ png_do_read_intrapixel(png_row_infop row_info, png_bytep row)
      }
   }
 }
-#endif /* MNG_FEATURES */
+#endif /* PNG_MNG_FEATURES_SUPPORTED */

 void PNGAPI
 png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row)
@@ -385,7 +385,7 @@ png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row)
   /* png_read_start_row sets the information (in particular iwidth) for this
    * interlace pass.
    */
-   if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
+   if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
      png_read_start_row(png_ptr);

   /* 1.5.6: row_info moved out of png_struct to a local here. */
@@ -396,47 +396,45 @@ png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row)
   row_info.pixel_depth = png_ptr->pixel_depth;
   row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);

-#ifdef PNG_WARNINGS_SUPPORTED
   if (png_ptr->row_number == 0 && png_ptr->pass == 0)
   {
   /* Check for transforms that have been set but were defined out */
 #if defined(PNG_WRITE_INVERT_SUPPORTED) && !defined(PNG_READ_INVERT_SUPPORTED)
-   if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
+   if (png_ptr->transformations & PNG_INVERT_MONO)
      png_warning(png_ptr, "PNG_READ_INVERT_SUPPORTED is not defined");
 #endif

 #if defined(PNG_WRITE_FILLER_SUPPORTED) && !defined(PNG_READ_FILLER_SUPPORTED)
-   if ((png_ptr->transformations & PNG_FILLER) != 0)
+   if (png_ptr->transformations & PNG_FILLER)
      png_warning(png_ptr, "PNG_READ_FILLER_SUPPORTED is not defined");
 #endif

 #if defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
    !defined(PNG_READ_PACKSWAP_SUPPORTED)
-   if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
+   if (png_ptr->transformations & PNG_PACKSWAP)
      png_warning(png_ptr, "PNG_READ_PACKSWAP_SUPPORTED is not defined");
 #endif

 #if defined(PNG_WRITE_PACK_SUPPORTED) && !defined(PNG_READ_PACK_SUPPORTED)
-   if ((png_ptr->transformations & PNG_PACK) != 0)
+   if (png_ptr->transformations & PNG_PACK)
      png_warning(png_ptr, "PNG_READ_PACK_SUPPORTED is not defined");
 #endif

 #if defined(PNG_WRITE_SHIFT_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED)
-   if ((png_ptr->transformations & PNG_SHIFT) != 0)
+   if (png_ptr->transformations & PNG_SHIFT)
      png_warning(png_ptr, "PNG_READ_SHIFT_SUPPORTED is not defined");
 #endif

 #if defined(PNG_WRITE_BGR_SUPPORTED) && !defined(PNG_READ_BGR_SUPPORTED)
-   if ((png_ptr->transformations & PNG_BGR) != 0)
+   if (png_ptr->transformations & PNG_BGR)
      png_warning(png_ptr, "PNG_READ_BGR_SUPPORTED is not defined");
 #endif

 #if defined(PNG_WRITE_SWAP_SUPPORTED) && !defined(PNG_READ_SWAP_SUPPORTED)
-   if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
+   if (png_ptr->transformations & PNG_SWAP_BYTES)
      png_warning(png_ptr, "PNG_READ_SWAP_SUPPORTED is not defined");
 #endif
   }
-#endif /* WARNINGS */

 #ifdef PNG_READ_INTERLACING_SUPPORTED
   /* If interlaced and we do not need a new row, combine row and return.
@@ -445,8 +443,7 @@ png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row)
    * untransformed) and, because of the libpng API for interlaced images, this
    * means we must transform before de-interlacing.
    */
-   if (png_ptr->interlaced != 0 &&
-       (png_ptr->transformations & PNG_INTERLACE) != 0)
+   if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
   {
      switch (png_ptr->pass)
      {
@@ -517,7 +514,7 @@ png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row)

         default:
         case 6:
-            if ((png_ptr->row_number & 1) == 0)
+            if (!(png_ptr->row_number & 1))
            {
               png_read_finish_row(png_ptr);
               return;
@@ -527,7 +524,7 @@ png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row)
   }
 #endif

-   if ((png_ptr->mode & PNG_HAVE_IDAT) == 0)
+   if (!(png_ptr->mode & PNG_HAVE_IDAT))
      png_error(png_ptr, "Invalid attempt to read row data");

   /* Fill the row with IDAT data: */
@@ -550,7 +547,7 @@ png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row)
   memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1);

 #ifdef PNG_MNG_FEATURES_SUPPORTED
-   if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
+   if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
       (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
   {
      /* Intrapixel differencing */
@@ -576,8 +573,8 @@ png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row)

 #ifdef PNG_READ_INTERLACING_SUPPORTED
   /* Expand interlaced rows to full size */
-   if (png_ptr->interlaced != 0 &&
-      (png_ptr->transformations & PNG_INTERLACE) != 0)
+   if (png_ptr->interlaced &&
+      (png_ptr->transformations & PNG_INTERLACE))
   {
      if (png_ptr->pass < 6)
         png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
@@ -605,7 +602,7 @@ png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row)
      (*(png_ptr->read_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);

 }
-#endif /* SEQUENTIAL_READ */
+#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */

 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
 /* Read one or more rows of image data.  If the image is interlaced,
@@ -672,7 +669,7 @@ png_read_rows(png_structrp png_ptr, png_bytepp row,
         dp++;
      }
 }
-#endif /* SEQUENTIAL_READ */
+#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */

 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
 /* Read the entire image.  If the image has an alpha channel or a tRNS
@@ -700,7 +697,7 @@ png_read_image(png_structrp png_ptr, png_bytepp image)
      return;

 #ifdef PNG_READ_INTERLACING_SUPPORTED
-   if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
+   if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
   {
      pass = png_set_interlace_handling(png_ptr);
      /* And make sure transforms are initialized. */
@@ -708,8 +705,7 @@ png_read_image(png_structrp png_ptr, png_bytepp image)
   }
   else
   {
-      if (png_ptr->interlaced != 0 &&
-          (png_ptr->transformations & PNG_INTERLACE) == 0)
+      if (png_ptr->interlaced && !(png_ptr->transformations & PNG_INTERLACE))
      {
         /* Caller called png_start_read_image or png_read_update_info without
          * first turning on the PNG_INTERLACE transform.  We can fix this here,
@@ -746,7 +742,7 @@ png_read_image(png_structrp png_ptr, png_bytepp image)
      }
   }
 }
-#endif /* SEQUENTIAL_READ */
+#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */

 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
 /* Read the end of the PNG file.  Will not read past the end of the
@@ -769,7 +765,7 @@ png_read_end(png_structrp png_ptr, png_inforp info_ptr)
    * still be pending IDAT data and an owned zstream.  Deal with this here.
    */
 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
-   if (png_chunk_unknown_handling(png_ptr, png_IDAT) == 0)
+   if (!png_chunk_unknown_handling(png_ptr, png_IDAT))
 #endif
      png_read_finish_IDAT(png_ptr);

@@ -799,9 +795,8 @@ png_read_end(png_structrp png_ptr, png_inforp info_ptr)
      {
         if (chunk_name == png_IDAT)
         {
-            if ((length > 0) ||
-                (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) != 0)
-               png_benign_error(png_ptr, "Too many IDATs found(a1)");
+            if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
+               png_benign_error(png_ptr, "Too many IDATs found");
         }
         png_handle_unknown(png_ptr, info_ptr, length, keep);
         if (chunk_name == png_PLTE)
@@ -814,8 +809,8 @@ png_read_end(png_structrp png_ptr, png_inforp info_ptr)
         /* Zero length IDATs are legal after the last IDAT has been
          * read, but not after other chunks have been read.
          */
-         if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) != 0)
-            png_benign_error(png_ptr, "Too many IDATs found(a2)");
+         if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
+            png_benign_error(png_ptr, "Too many IDATs found");

         png_crc_finish(png_ptr, length);
      }
@@ -910,9 +905,9 @@ png_read_end(png_structrp png_ptr, png_inforp info_ptr)
      else
         png_handle_unknown(png_ptr, info_ptr, length,
            PNG_HANDLE_CHUNK_AS_DEFAULT);
-   } while ((png_ptr->mode & PNG_HAVE_IEND) == 0);
+   } while (!(png_ptr->mode & PNG_HAVE_IEND));
 }
-#endif /* SEQUENTIAL_READ */
+#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */

 /* Free all memory used in the read struct */
 static void
@@ -925,33 +920,22 @@ png_read_destroy(png_structrp png_ptr)
 #endif

   png_free(png_ptr, png_ptr->big_row_buf);
-   png_ptr->big_row_buf = NULL;
   png_free(png_ptr, png_ptr->big_prev_row);
-   png_ptr->big_prev_row = NULL;
   png_free(png_ptr, png_ptr->read_buffer);
-   png_ptr->read_buffer = NULL;

 #ifdef PNG_READ_QUANTIZE_SUPPORTED
   png_free(png_ptr, png_ptr->palette_lookup);
-   png_ptr->palette_lookup = NULL;
   png_free(png_ptr, png_ptr->quantize_index);
-   png_ptr->quantize_index = NULL;
 #endif

-   if ((png_ptr->free_me & PNG_FREE_PLTE) != 0)
-   {
+   if (png_ptr->free_me & PNG_FREE_PLTE)
      png_zfree(png_ptr, png_ptr->palette);
-      png_ptr->palette = NULL;
-   }
   png_ptr->free_me &= ~PNG_FREE_PLTE;

 #if defined(PNG_tRNS_SUPPORTED) || \
    defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
-   if ((png_ptr->free_me & PNG_FREE_TRNS) != 0)
-   {
+   if (png_ptr->free_me & PNG_FREE_TRNS)
      png_free(png_ptr, png_ptr->trans_alpha);
-      png_ptr->trans_alpha = NULL;
-   }
   png_ptr->free_me &= ~PNG_FREE_TRNS;
 #endif

@@ -959,18 +943,15 @@ png_read_destroy(png_structrp png_ptr)

 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
   png_free(png_ptr, png_ptr->save_buffer);
-   png_ptr->save_buffer = NULL;
 #endif

 #if defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) && \
   defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
   png_free(png_ptr, png_ptr->unknown_chunk.data);
-   png_ptr->unknown_chunk.data = NULL;
 #endif

 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
   png_free(png_ptr, png_ptr->chunk_list);
-   png_ptr->chunk_list = NULL;
 #endif

   /* NOTE: the 'setjmp' buffer may still be allocated and the memory and error
@@ -1042,7 +1023,7 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,

   /* Tell libpng to strip 16-bit/color files down to 8 bits per color.
    */
-   if ((transforms & PNG_TRANSFORM_SCALE_16) != 0)
+   if (transforms & PNG_TRANSFORM_SCALE_16)
     /* Added at libpng-1.5.4. "strip_16" produces the same result that it
      * did in earlier versions, while "scale_16" is now more accurate.
      */
@@ -1056,7 +1037,7 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,
    * latter by doing SCALE first.  This is ok and allows apps not to check for
    * which is supported to get the right answer.
    */
-   if ((transforms & PNG_TRANSFORM_STRIP_16) != 0)
+   if (transforms & PNG_TRANSFORM_STRIP_16)
 #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
      png_set_strip_16(png_ptr);
 #else
@@ -1066,7 +1047,7 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,
   /* Strip alpha bytes from the input data without combining with
    * the background (not recommended).
    */
-   if ((transforms & PNG_TRANSFORM_STRIP_ALPHA) != 0)
+   if (transforms & PNG_TRANSFORM_STRIP_ALPHA)
 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
      png_set_strip_alpha(png_ptr);
 #else
@@ -1076,7 +1057,7 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,
   /* Extract multiple pixels with bit depths of 1, 2, or 4 from a single
    * byte into separate bytes (useful for paletted and grayscale images).
    */
-   if ((transforms & PNG_TRANSFORM_PACKING) != 0)
+   if (transforms & PNG_TRANSFORM_PACKING)
 #ifdef PNG_READ_PACK_SUPPORTED
      png_set_packing(png_ptr);
 #else
@@ -1086,7 +1067,7 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,
   /* Change the order of packed pixels to least significant bit first
    * (not useful if you are using png_set_packing).
    */
-   if ((transforms & PNG_TRANSFORM_PACKSWAP) != 0)
+   if (transforms & PNG_TRANSFORM_PACKSWAP)
 #ifdef PNG_READ_PACKSWAP_SUPPORTED
      png_set_packswap(png_ptr);
 #else
@@ -1098,7 +1079,7 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,
    * Expand paletted or RGB images with transparency to full alpha
    * channels so the data will be available as RGBA quartets.
    */
-   if ((transforms & PNG_TRANSFORM_EXPAND) != 0)
+   if (transforms & PNG_TRANSFORM_EXPAND)
 #ifdef PNG_READ_EXPAND_SUPPORTED
      png_set_expand(png_ptr);
 #else
@@ -1110,7 +1091,7 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,

   /* Invert monochrome files to have 0 as white and 1 as black
    */
-   if ((transforms & PNG_TRANSFORM_INVERT_MONO) != 0)
+   if (transforms & PNG_TRANSFORM_INVERT_MONO)
 #ifdef PNG_READ_INVERT_SUPPORTED
      png_set_invert_mono(png_ptr);
 #else
@@ -1121,16 +1102,16 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,
    * [0,65535] to the original [0,7] or [0,31], or whatever range the
    * colors were originally in:
    */
-   if ((transforms & PNG_TRANSFORM_SHIFT) != 0)
+   if (transforms & PNG_TRANSFORM_SHIFT)
 #ifdef PNG_READ_SHIFT_SUPPORTED
-      if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
+      if (info_ptr->valid & PNG_INFO_sBIT)
         png_set_shift(png_ptr, &info_ptr->sig_bit);
 #else
      png_app_error(png_ptr, "PNG_TRANSFORM_SHIFT not supported");
 #endif

   /* Flip the RGB pixels to BGR (or RGBA to BGRA) */
-   if ((transforms & PNG_TRANSFORM_BGR) != 0)
+   if (transforms & PNG_TRANSFORM_BGR)
 #ifdef PNG_READ_BGR_SUPPORTED
      png_set_bgr(png_ptr);
 #else
@@ -1138,7 +1119,7 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,
 #endif

   /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */
-   if ((transforms & PNG_TRANSFORM_SWAP_ALPHA) != 0)
+   if (transforms & PNG_TRANSFORM_SWAP_ALPHA)
 #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
      png_set_swap_alpha(png_ptr);
 #else
@@ -1146,7 +1127,7 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,
 #endif

   /* Swap bytes of 16-bit files to least significant byte first */
-   if ((transforms & PNG_TRANSFORM_SWAP_ENDIAN) != 0)
+   if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
 #ifdef PNG_READ_SWAP_SUPPORTED
      png_set_swap(png_ptr);
 #else
@@ -1155,7 +1136,7 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,

 /* Added at libpng-1.2.41 */
   /* Invert the alpha channel from opacity to transparency */
-   if ((transforms & PNG_TRANSFORM_INVERT_ALPHA) != 0)
+   if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
 #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
      png_set_invert_alpha(png_ptr);
 #else
@@ -1164,7 +1145,7 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,

 /* Added at libpng-1.2.41 */
   /* Expand grayscale image to RGB */
-   if ((transforms & PNG_TRANSFORM_GRAY_TO_RGB) != 0)
+   if (transforms & PNG_TRANSFORM_GRAY_TO_RGB)
 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
      png_set_gray_to_rgb(png_ptr);
 #else
@@ -1172,7 +1153,7 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,
 #endif

 /* Added at libpng-1.5.4 */
-   if ((transforms & PNG_TRANSFORM_EXPAND_16) != 0)
+   if (transforms & PNG_TRANSFORM_EXPAND_16)
 #ifdef PNG_READ_EXPAND_16_SUPPORTED
      png_set_expand_16(png_ptr);
 #else
@@ -1220,8 +1201,8 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,

   PNG_UNUSED(params)
 }
-#endif /* INFO_IMAGE */
-#endif /* SEQUENTIAL_READ */
+#endif /* PNG_INFO_IMAGE_SUPPORTED */
+#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */

 #ifdef PNG_SIMPLIFIED_READ_SUPPORTED
 /* SIMPLIFIED READ
@@ -1330,10 +1311,10 @@ png_image_format(png_structrp png_ptr)
 {
   png_uint_32 format = 0;

-   if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
+   if (png_ptr->color_type & PNG_COLOR_MASK_COLOR)
      format |= PNG_FORMAT_FLAG_COLOR;

-   if ((png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)
+   if (png_ptr->color_type & PNG_COLOR_MASK_ALPHA)
      format |= PNG_FORMAT_FLAG_ALPHA;

   /* Use png_ptr here, not info_ptr, because by examination png_handle_tRNS
@@ -1347,7 +1328,7 @@ png_image_format(png_structrp png_ptr)
   if (png_ptr->bit_depth == 16)
      format |= PNG_FORMAT_FLAG_LINEAR;

-   if ((png_ptr->color_type & PNG_COLOR_MASK_PALETTE) != 0)
+   if (png_ptr->color_type & PNG_COLOR_MASK_PALETTE)
      format |= PNG_FORMAT_FLAG_COLORMAP;

   return format;
@@ -1447,7 +1428,7 @@ png_image_begin_read_from_stdio(png_imagep image, FILE* file)
   {
      if (file != NULL)
      {
-         if (png_image_read_init(image) != 0)
+         if (png_image_read_init(image))
         {
            /* This is slightly evil, but png_init_io doesn't do anything other
             * than this and we haven't changed the standard IO functions so
@@ -1481,7 +1462,7 @@ png_image_begin_read_from_file(png_imagep image, const char *file_name)

         if (fp != NULL)
         {
-            if (png_image_read_init(image) != 0)
+            if (png_image_read_init(image))
            {
               image->opaque->png_ptr->io_ptr = fp;
               image->opaque->owned_file = 1;
@@ -1507,7 +1488,7 @@ png_image_begin_read_from_file(png_imagep image, const char *file_name)

   return 0;
 }
-#endif /* STDIO */
+#endif /* PNG_STDIO_SUPPORTED */

 static void PNGCBAPI
 png_image_memory_read(png_structp png_ptr, png_bytep out, png_size_t need)
@@ -1546,7 +1527,7 @@ int PNGAPI png_image_begin_read_from_memory(png_imagep image,
   {
      if (memory != NULL && size > 0)
      {
-         if (png_image_read_init(image) != 0)
+         if (png_image_read_init(image))
         {
            /* Now set the IO functions to read from the memory buffer and
             * store it into io_ptr.  Again do this in-place to avoid calling a
@@ -1618,14 +1599,14 @@ png_image_skip_unused_chunks(png_structrp png_ptr)

       /* But do not ignore image data handling chunks */
       png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_AS_DEFAULT,
-         chunks_to_process, (int)/*SAFE*/(sizeof chunks_to_process)/5);
+         chunks_to_process, (sizeof chunks_to_process)/5);
    }
 }

 #  define PNG_SKIP_CHUNKS(p) png_image_skip_unused_chunks(p)
 #else
 #  define PNG_SKIP_CHUNKS(p) ((void)0)
-#endif /* HANDLE_AS_UNKNOWN */
+#endif /* PNG_HANDLE_AS_UNKNOWN_SUPPORTED */

 /* The following macro gives the exact rounded answer for all values in the
 * range 0..255 (it actually divides by 51.2, but the rounding still generates
@@ -1638,9 +1619,9 @@ static void
 set_file_encoding(png_image_read_control *display)
 {
   png_fixed_point g = display->image->opaque->png_ptr->colorspace.gamma;
-   if (png_gamma_significant(g) != 0)
+   if (png_gamma_significant(g))
   {
-      if (png_gamma_not_sRGB(g) != 0)
+      if (png_gamma_not_sRGB(g))
      {
         display->file_encoding = P_FILE;
         display->gamma_to_linear = png_reciprocal(g);
@@ -1735,7 +1716,7 @@ png_create_colormap_entry(png_image_read_control *display,
   png_uint_32 alpha, int encoding)
 {
   png_imagep image = display->image;
-   const int output_encoding = (image->format & PNG_FORMAT_FLAG_LINEAR) != 0 ?
+   const int output_encoding = (image->format & PNG_FORMAT_FLAG_LINEAR) ?
      P_LINEAR : P_sRGB;
   const int convert_to_Y = (image->format & PNG_FORMAT_FLAG_COLOR) == 0 &&
      (red != green || green != blue);
@@ -1765,7 +1746,7 @@ png_create_colormap_entry(png_image_read_control *display,
      green = png_gamma_16bit_correct(green*257, g);
      blue = png_gamma_16bit_correct(blue*257, g);

-      if (convert_to_Y != 0 || output_encoding == P_LINEAR)
+      if (convert_to_Y || output_encoding == P_LINEAR)
      {
         alpha *= 257;
         encoding = P_LINEAR;
@@ -1792,8 +1773,7 @@ png_create_colormap_entry(png_image_read_control *display,
      encoding = P_LINEAR;
   }

-   else if (encoding == P_sRGB &&
-       (convert_to_Y  != 0 || output_encoding == P_LINEAR))
+   else if (encoding == P_sRGB && (convert_to_Y || output_encoding == P_LINEAR))
   {
      /* The values are 8-bit sRGB values, but must be converted to 16-bit
       * linear.
@@ -1851,7 +1831,7 @@ png_create_colormap_entry(png_image_read_control *display,
 #        define afirst 0
 #     endif
 #     ifdef PNG_FORMAT_BGR_SUPPORTED
-         const int bgr = (image->format & PNG_FORMAT_FLAG_BGR) != 0 ? 2 : 0;
+         const int bgr = (image->format & PNG_FORMAT_FLAG_BGR) ? 2 : 0;
 #     else
 #        define bgr 0
 #     endif
@@ -2063,7 +2043,7 @@ png_image_read_colormap(png_voidp argument)

   const png_structrp png_ptr = image->opaque->png_ptr;
   const png_uint_32 output_format = image->format;
-   const int output_encoding = (output_format & PNG_FORMAT_FLAG_LINEAR) != 0 ?
+   const int output_encoding = (output_format & PNG_FORMAT_FLAG_LINEAR) ?
      P_LINEAR : P_sRGB;

   unsigned int cmap_entries;
@@ -2102,7 +2082,7 @@ png_image_read_colormap(png_voidp argument)
      else
      {
         back_g = display->background->green;
-         if ((output_format & PNG_FORMAT_FLAG_COLOR) != 0)
+         if (output_format & PNG_FORMAT_FLAG_COLOR)
         {
            back_r = display->background->red;
            back_b = display->background->blue;
@@ -2244,7 +2224,7 @@ png_image_read_colormap(png_voidp argument)
            {
               unsigned int back_alpha;

-               if ((output_format & PNG_FORMAT_FLAG_ALPHA) != 0)
+               if (output_format & PNG_FORMAT_FLAG_ALPHA)
                  back_alpha = 0;

               else
@@ -2285,14 +2265,8 @@ png_image_read_colormap(png_voidp argument)
                     output_processing = PNG_CMAP_NONE;
                     break;
                  }
-#ifdef __COVERITY__
-                 /* Coverity claims that output_encoding cannot be 2 (P_LINEAR)
-                  * here.
-                  */
-                  back_alpha = 255;
-#else
+
                  back_alpha = output_encoding == P_LINEAR ? 65535 : 255;
-#endif
               }

               /* output_processing means that the libpng-processed row will be
@@ -2331,7 +2305,7 @@ png_image_read_colormap(png_voidp argument)
          */
         data_encoding = P_sRGB;

-         if ((output_format & PNG_FORMAT_FLAG_ALPHA) != 0)
+         if (output_format & PNG_FORMAT_FLAG_ALPHA)
         {
            if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries)
               png_error(png_ptr, "gray+alpha color-map: too few entries");
@@ -2417,14 +2391,7 @@ png_image_read_colormap(png_voidp argument)
                */
               background_index = i;
               png_create_colormap_entry(display, i++, back_r, back_g, back_b,
-#ifdef __COVERITY__
-                 /* Coverity claims that output_encoding cannot be 2 (P_LINEAR)
-                  * here.
-                  */ 255U,
-#else
-                  output_encoding == P_LINEAR ? 65535U : 255U,
-#endif
-                  output_encoding);
+                  output_encoding == P_LINEAR ? 65535U : 255U, output_encoding);

               /* For non-opaque input composite on the sRGB background - this
                * requires inverting the encoding for each component.  The input
@@ -2533,7 +2500,7 @@ png_image_read_colormap(png_voidp argument)
                */
               if ((png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
                  png_ptr->num_trans > 0) &&
-                  png_gamma_not_sRGB(png_ptr->colorspace.gamma) != 0)
+                  png_gamma_not_sRGB(png_ptr->colorspace.gamma))
               {
                  cmap_entries = make_gray_file_colormap(display);
                  data_encoding = P_FILE;
@@ -2621,7 +2588,7 @@ png_image_read_colormap(png_voidp argument)
               /* Is there alpha in the output too?  If so all four channels are
                * processed into a special RGB cube with alpha support.
                */
-               if ((output_format & PNG_FORMAT_FLAG_ALPHA) != 0)
+               if (output_format & PNG_FORMAT_FLAG_ALPHA)
               {
                  png_uint_32 r;

@@ -2795,7 +2762,7 @@ png_image_read_colormap(png_voidp argument)

            for (i=0; i < cmap_entries; ++i)
            {
-               if (do_background != 0 && i < num_trans && trans[i] < 255)
+               if (do_background && i < num_trans && trans[i] < 255)
               {
                  if (trans[i] == 0)
                     png_create_colormap_entry(display, i, back_r, back_g,
@@ -2840,8 +2807,8 @@ png_image_read_colormap(png_voidp argument)
   }

   /* Now deal with the output processing */
-   if (expand_tRNS != 0 && png_ptr->num_trans > 0 &&
-       (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) == 0)
+   if (expand_tRNS && png_ptr->num_trans > 0 &&
+      (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) == 0)
      png_set_tRNS_to_alpha(png_ptr);

   switch (data_encoding)
@@ -3257,8 +3224,7 @@ png_image_read_composite(png_voidp argument)
      png_uint_32  height = image->height;
      png_uint_32  width = image->width;
      ptrdiff_t    step_row = display->row_bytes;
-      unsigned int channels =
-          (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ? 3 : 1;
+      unsigned int channels = (image->format & PNG_FORMAT_FLAG_COLOR) ? 3 : 1;
      int pass;

      for (pass = 0; pass < passes; ++pass)
@@ -3556,8 +3522,7 @@ png_image_read_background(png_voidp argument)
            int swap_alpha = 0;

 #           ifdef PNG_SIMPLIFIED_READ_AFIRST_SUPPORTED
-               if (preserve_alpha != 0 &&
-                   (image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
+               if (preserve_alpha && (image->format & PNG_FORMAT_FLAG_AFIRST))
                  swap_alpha = 1;
 #           endif

@@ -3666,10 +3631,10 @@ png_image_read_direct(png_voidp argument)
      int mode; /* alpha mode */

      /* Do this first so that we have a record if rgb to gray is happening. */
-      if ((change & PNG_FORMAT_FLAG_COLOR) != 0)
+      if (change & PNG_FORMAT_FLAG_COLOR)
      {
         /* gray<->color transformation required. */
-         if ((format & PNG_FORMAT_FLAG_COLOR) != 0)
+         if (format & PNG_FORMAT_FLAG_COLOR)
            png_set_gray_to_rgb(png_ptr);

         else
@@ -3687,7 +3652,7 @@ png_image_read_direct(png_voidp argument)
             * enormous change) 'do_local_background' is used to indicate that
             * the problem exists.
             */
-            if ((base_format & PNG_FORMAT_FLAG_ALPHA) != 0)
+            if (base_format & PNG_FORMAT_FLAG_ALPHA)
               do_local_background = 1/*maybe*/;

            png_set_rgb_to_gray_fixed(png_ptr, PNG_ERROR_ACTION_NONE,
@@ -3702,8 +3667,8 @@ png_image_read_direct(png_voidp argument)
      {
         png_fixed_point input_gamma_default;

-         if ((base_format & PNG_FORMAT_FLAG_LINEAR) != 0 &&
-             (image->flags & PNG_IMAGE_FLAG_16BIT_sRGB) == 0)
+         if ((base_format & PNG_FORMAT_FLAG_LINEAR) &&
+            (image->flags & PNG_IMAGE_FLAG_16BIT_sRGB) == 0)
            input_gamma_default = PNG_GAMMA_LINEAR;
         else
            input_gamma_default = PNG_DEFAULT_sRGB;
@@ -3719,7 +3684,7 @@ png_image_read_direct(png_voidp argument)
         /* If there *is* an alpha channel in the input it must be multiplied
          * out; use PNG_ALPHA_STANDARD, otherwise just use PNG_ALPHA_PNG.
          */
-         if ((base_format & PNG_FORMAT_FLAG_ALPHA) != 0)
+         if (base_format & PNG_FORMAT_FLAG_ALPHA)
            mode = PNG_ALPHA_STANDARD; /* associated alpha */

         else
@@ -3750,7 +3715,7 @@ png_image_read_direct(png_voidp argument)
          * final value.
          */
         if (png_muldiv(&gtest, output_gamma, png_ptr->colorspace.gamma,
-               PNG_FP_1) != 0 && png_gamma_significant(gtest) == 0)
+               PNG_FP_1) && !png_gamma_significant(gtest))
            do_local_background = 0;

         else if (mode == PNG_ALPHA_STANDARD)
@@ -3763,9 +3728,9 @@ png_image_read_direct(png_voidp argument)
      }

      /* If the bit-depth changes then handle that here. */
-      if ((change & PNG_FORMAT_FLAG_LINEAR) != 0)
+      if (change & PNG_FORMAT_FLAG_LINEAR)
      {
-         if (linear != 0 /*16-bit output*/)
+         if (linear /*16-bit output*/)
            png_set_expand_16(png_ptr);

         else /* 8-bit output */
@@ -3775,13 +3740,13 @@ png_image_read_direct(png_voidp argument)
      }

      /* Now the background/alpha channel changes. */
-      if ((change & PNG_FORMAT_FLAG_ALPHA) != 0)
+      if (change & PNG_FORMAT_FLAG_ALPHA)
      {
         /* Removing an alpha channel requires composition for the 8-bit
          * formats; for the 16-bit it is already done, above, by the
          * pre-multiplication and the channel just needs to be stripped.
          */
-         if ((base_format & PNG_FORMAT_FLAG_ALPHA) != 0)
+         if (base_format & PNG_FORMAT_FLAG_ALPHA)
         {
            /* If RGB->gray is happening the alpha channel must be left and the
             * operation completed locally.
@@ -3846,7 +3811,7 @@ png_image_read_direct(png_voidp argument)
               filler = 255;

 #           ifdef PNG_FORMAT_AFIRST_SUPPORTED
-               if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
+               if (format & PNG_FORMAT_FLAG_AFIRST)
               {
                  where = PNG_FILLER_BEFORE;
                  change &= ~PNG_FORMAT_FLAG_AFIRST;
@@ -3870,12 +3835,12 @@ png_image_read_direct(png_voidp argument)
      png_set_alpha_mode_fixed(png_ptr, mode, output_gamma);

 #     ifdef PNG_FORMAT_BGR_SUPPORTED
-         if ((change & PNG_FORMAT_FLAG_BGR) != 0)
+         if (change & PNG_FORMAT_FLAG_BGR)
         {
            /* Check only the output format; PNG is never BGR; don't do this if
             * the output is gray, but fix up the 'format' value in that case.
             */
-            if ((format & PNG_FORMAT_FLAG_COLOR) != 0)
+            if (format & PNG_FORMAT_FLAG_COLOR)
               png_set_bgr(png_ptr);

            else
@@ -3886,14 +3851,14 @@ png_image_read_direct(png_voidp argument)
 #     endif

 #     ifdef PNG_FORMAT_AFIRST_SUPPORTED
-         if ((change & PNG_FORMAT_FLAG_AFIRST) != 0)
+         if (change & PNG_FORMAT_FLAG_AFIRST)
         {
            /* Only relevant if there is an alpha channel - it's particularly
             * important to handle this correctly because do_local_compose may
             * be set above and then libpng will keep the alpha channel for this
             * code to remove.
             */
-            if ((format & PNG_FORMAT_FLAG_ALPHA) != 0)
+            if (format & PNG_FORMAT_FLAG_ALPHA)
            {
               /* Disable this if doing a local background,
                * TODO: remove this when local background is no longer required.
@@ -3916,7 +3881,7 @@ png_image_read_direct(png_voidp argument)
      {
         PNG_CONST png_uint_16 le = 0x0001;

-         if ((*(png_const_bytep) & le) != 0)
+         if (*(png_const_bytep)&le)
            png_set_swap(png_ptr);
      }

@@ -3941,10 +3906,10 @@ png_image_read_direct(png_voidp argument)
   {
      png_uint_32 info_format = 0;

-      if ((info_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
+      if (info_ptr->color_type & PNG_COLOR_MASK_COLOR)
         info_format |= PNG_FORMAT_FLAG_COLOR;

-      if ((info_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)
+      if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
      {
         /* do_local_compose removes this channel below. */
         if (do_local_compose == 0)
@@ -3963,14 +3928,14 @@ png_image_read_direct(png_voidp argument)
         info_format |= PNG_FORMAT_FLAG_LINEAR;

 #     ifdef PNG_FORMAT_BGR_SUPPORTED
-         if ((png_ptr->transformations & PNG_BGR) != 0)
+         if (png_ptr->transformations & PNG_BGR)
            info_format |= PNG_FORMAT_FLAG_BGR;
 #     endif

 #     ifdef PNG_FORMAT_AFIRST_SUPPORTED
         if (do_local_background == 2)
         {
-            if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
+            if (format & PNG_FORMAT_FLAG_AFIRST)
               info_format |= PNG_FORMAT_FLAG_AFIRST;
         }

@@ -4099,7 +4064,7 @@ png_image_finish_read(png_imagep image, png_const_colorp background,
            /* Choose the correct 'end' routine; for the color-map case all the
             * setup has already been done.
             */
-            if ((image->format & PNG_FORMAT_FLAG_COLORMAP) != 0)
+            if (image->format & PNG_FORMAT_FLAG_COLORMAP)
               result =
                  png_safe_execute(image, png_image_read_colormap, &display) &&
                  png_safe_execute(image, png_image_read_colormapped, &display);
@@ -4129,5 +4094,5 @@ png_image_finish_read(png_imagep image, png_const_colorp background,
   return 0;
 }

-#endif /* SIMPLIFIED_READ */
-#endif /* READ */
+#endif /* PNG_SIMPLIFIED_READ_SUPPORTED */
+#endif /* PNG_READ_SUPPORTED */
--- a/pngrio.c
+++ b/pngrio.c
@@ -1,8 +1,8 @@

 /* pngrio.c - functions for data input
 *
- * Last changed in libpng 1.6.17 [(PENDING RELEASE)]
- * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.9 [February 6, 2014]
+ * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
@@ -117,4 +117,4 @@ png_set_read_fn(png_structrp png_ptr, png_voidp io_ptr,
   png_ptr->output_flush_fn = NULL;
 #endif
 }
-#endif /* READ */
+#endif /* PNG_READ_SUPPORTED */
--- a/pngrtran.c
+++ b/pngrtran.c
--- a/pngrutil.c
+++ b/pngrutil.c
@@ -1,8 +1,8 @@

 /* pngrutil.c - utilities to read a PNG file
 *
- * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.11 [June 5, 2014]
+ * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
@@ -18,6 +18,17 @@

 #ifdef PNG_READ_SUPPORTED

+png_uint_32 PNGAPI
+png_get_uint_31(png_const_structrp png_ptr, png_const_bytep buf)
+{
+   png_uint_32 uval = png_get_uint_32(buf);
+
+   if (uval > PNG_UINT_31_MAX)
+      png_error(png_ptr, "PNG unsigned integer out of range");
+
+   return (uval);
+}
+
 #if defined(PNG_READ_gAMA_SUPPORTED) || defined(PNG_READ_cHRM_SUPPORTED)
 /* The following is a variation on the above for use with the fixed
 * point values used for gAMA and cHRM.  Instead of png_error it
@@ -40,7 +51,7 @@ png_get_fixed_point(png_structrp png_ptr, png_const_bytep buf)

   return PNG_FIXED_ERROR;
 }
-#endif /* READ_gAMA or READ_cHRM */
+#endif

 #ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
 /* NOTE: the read macros will obscure these definitions, so that if
@@ -56,7 +67,13 @@ png_get_fixed_point(png_structrp png_ptr, png_const_bytep buf)
 png_uint_32 (PNGAPI
 png_get_uint_32)(png_const_bytep buf)
 {
-   return PNG_U32(buf[0], buf[1], buf[2], buf[3]);
+   png_uint_32 uval =
+       ((png_uint_32)(*(buf    )) << 24) +
+       ((png_uint_32)(*(buf + 1)) << 16) +
+       ((png_uint_32)(*(buf + 2)) <<  8) +
+       ((png_uint_32)(*(buf + 3))      ) ;
+
+   return uval;
 }

 /* Grab a signed 32-bit integer from a buffer in big-endian format.  The
@@ -67,31 +84,31 @@ png_get_uint_32)(png_const_bytep buf)
 png_int_32 (PNGAPI
 png_get_int_32)(png_const_bytep buf)
 {
-   return PNG_S32(buf[0], buf[1], buf[2], buf[3]);
+   png_uint_32 uval = png_get_uint_32(buf);
+   if ((uval & 0x80000000) == 0) /* non-negative */
+      return uval;
+
+   uval = (uval ^ 0xffffffff) + 1;  /* 2's complement: -x = ~x+1 */
+   return -(png_int_32)uval;
 }

 /* Grab an unsigned 16-bit integer from a buffer in big-endian format. */
 png_uint_16 (PNGAPI
 png_get_uint_16)(png_const_bytep buf)
 {
-   return PNG_U16(buf[0], buf[1]);
+   /* ANSI-C requires an int value to accomodate at least 16 bits so this
+    * works and allows the compiler not to worry about possible narrowing
+    * on 32 bit systems.  (Pre-ANSI systems did not make integers smaller
+    * than 16 bits either.)
+    */
+   unsigned int val =
+       ((unsigned int)(*buf) << 8) +
+       ((unsigned int)(*(buf + 1)));
+
+   return (png_uint_16)val;
 }
-#endif /* READ_INT_FUNCTIONS */

-/* This is an exported function however its error handling is too harsh for most
- * internal use.  For example if it were used for reading the chunk parameters
- * it would error out even on ancillary chunks that can be ignored.
- */
-png_uint_32 PNGAPI
-png_get_uint_31(png_const_structrp png_ptr, png_const_bytep buf)
-{
-   png_uint_32 uval = png_get_uint_32(buf);
-
-   if (uval > PNG_UINT_31_MAX)
-      png_error(png_ptr, "PNG unsigned integer out of range");
-
-   return uval;
-}
+#endif /* PNG_READ_INT_FUNCTIONS_SUPPORTED */

 /* Read and check the PNG file signature */
 void /* PRIVATE */
@@ -203,8 +220,8 @@ png_crc_finish(png_structrp png_ptr, png_uint_32 skip)
   if (png_crc_error(png_ptr))
   {
      if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) ?
-          (png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) == 0:
-          (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_USE) != 0)
+          !(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) :
+          (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_USE))
      {
         png_chunk_warning(png_ptr, "CRC error");
      }
@@ -304,7 +321,7 @@ png_read_buffer(png_structrp png_ptr, png_alloc_size_t new_size, int warn)

   return buffer;
 }
-#endif /* READ_iCCP|iTXt|pCAL|sCAL|sPLT|tEXt|zTXt|SEQUENTIAL_READ */
+#endif /* PNG_READ_iCCP|iTXt|pCAL|sCAL|sPLT|tEXt|zTXt|SEQUENTIAL_READ */

 /* png_inflate_claim: claim the zstream for some nefarious purpose that involves
 * decompression.  Returns Z_OK on success, else a zlib error code.  It checks
@@ -501,7 +518,7 @@ png_inflate(png_structrp png_ptr, png_uint_32 owner, int finish,
          * end of the output buffer.
          */
         ret = inflate(&png_ptr->zstream, avail_out > 0 ? Z_NO_FLUSH :
-             (finish ? Z_FINISH : Z_SYNC_FLUSH));
+            (finish ? Z_FINISH : Z_SYNC_FLUSH));
      } while (ret == Z_OK);

      /* For safety kill the local buffer pointer now */
@@ -559,7 +576,7 @@ png_decompress_chunk(png_structrp png_ptr,
    */
   png_alloc_size_t limit = PNG_SIZE_MAX;

-#  ifdef PNG_SET_USER_LIMITS_SUPPORTED
+#  ifdef PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED
      if (png_ptr->user_chunk_malloc_max > 0 &&
         png_ptr->user_chunk_malloc_max < limit)
         limit = png_ptr->user_chunk_malloc_max;
@@ -701,7 +718,7 @@ png_decompress_chunk(png_structrp png_ptr,
      return Z_MEM_ERROR;
   }
 }
-#endif /* READ_COMPRESSED_TEXT */
+#endif /* PNG_READ_COMPRESSED_TEXT_SUPPORTED */

 #ifdef PNG_READ_iCCP_SUPPORTED
 /* Perform a partial read and decompress, producing 'avail_out' bytes and
@@ -969,9 +986,7 @@ png_handle_PLTE(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)

      /* Otherwise, we (optionally) emit a warning and use the chunk. */
      else if (!(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN))
-      {
         png_chunk_warning(png_ptr, "CRC error");
-      }
   }
 #endif

@@ -996,7 +1011,7 @@ png_handle_PLTE(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
    */
 #ifdef PNG_READ_tRNS_SUPPORTED
   if (png_ptr->num_trans > 0 ||
-       (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0))
+      (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0))
   {
      /* Cancel this because otherwise it would be used if the transforms
       * require it.  Don't cancel the 'valid' flag because this would prevent
@@ -1278,7 +1293,7 @@ png_handle_sRGB(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
   (void)png_colorspace_set_sRGB(png_ptr, &png_ptr->colorspace, intent);
   png_colorspace_sync(png_ptr, info_ptr);
 }
-#endif /* READ_sRGB */
+#endif /* PNG_READ_sRGB_SUPPORTED */

 #ifdef PNG_READ_iCCP_SUPPORTED
 void /* PRIVATE */
@@ -1316,7 +1331,7 @@ png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
   }

   /* If a colorspace error has already been output skip this chunk */
-   if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
+   if (png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID)
   {
      png_crc_finish(png_ptr, length);
      return;
@@ -1499,10 +1514,8 @@ png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
                                 else if (size > 0)
                                    errmsg = "truncated";

-#ifndef __COVERITY__
                                 else
                                    errmsg = png_ptr->zstream.msg;
-#endif
                              }

                              /* else png_icc_check_tag_table output an error */
@@ -1553,7 +1566,7 @@ png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
   if (errmsg != NULL) /* else already output */
      png_chunk_benign_error(png_ptr, errmsg);
 }
-#endif /* READ_iCCP */
+#endif /* PNG_READ_iCCP_SUPPORTED */

 #ifdef PNG_READ_sPLT_SUPPORTED
 void /* PRIVATE */
@@ -1582,8 +1595,7 @@ png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)

      if (--png_ptr->user_chunk_cache_max == 1)
      {
-         /* Warn the first time */
-         png_chunk_benign_error(png_ptr, "no space in chunk cache");
+         png_warning(png_ptr, "No space in chunk cache for sPLT");
         png_crc_finish(png_ptr, length);
         return;
      }
@@ -1660,8 +1672,8 @@ png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)

   if (dl > max_dl)
   {
-      png_warning(png_ptr, "sPLT chunk too long");
-      return;
+       png_warning(png_ptr, "sPLT chunk too long");
+       return;
   }

   new_palette.nentries = (png_int_32)(data_length / entry_size);
@@ -1671,8 +1683,8 @@ png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)

   if (new_palette.entries == NULL)
   {
-      png_warning(png_ptr, "sPLT chunk requires too much memory");
-      return;
+       png_warning(png_ptr, "sPLT chunk requires too much memory");
+       return;
   }

 #ifdef PNG_POINTER_INDEXING_SUPPORTED
@@ -1731,7 +1743,7 @@ png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)

   png_free(png_ptr, new_palette.entries);
 }
-#endif /* READ_sPLT */
+#endif /* PNG_READ_sPLT_SUPPORTED */

 #ifdef PNG_READ_tRNS_SUPPORTED
 void /* PRIVATE */
@@ -1833,9 +1845,6 @@ png_handle_tRNS(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
    */
   png_set_tRNS(png_ptr, info_ptr, readbuf, png_ptr->num_trans,
       &(png_ptr->trans_color));
-
-   if (info_ptr != NULL)
-      png_ptr->trans_alpha = info_ptr->trans_alpha;
 }
 #endif

@@ -2663,7 +2672,7 @@ png_handle_iTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)

         buffer[uncompressed_length+prefix_length] = 0;

-         if (compressed == 0)
+         if (compressed != 0)
            text.compression = PNG_ITXT_COMPRESSION_NONE;

         else
@@ -2702,7 +2711,7 @@ png_cache_unknown_chunk(png_structrp png_ptr, png_uint_32 length)
      png_ptr->unknown_chunk.data = NULL;
   }

-#  ifdef PNG_SET_USER_LIMITS_SUPPORTED
+#  ifdef PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED
      if (png_ptr->user_chunk_malloc_max > 0 &&
         png_ptr->user_chunk_malloc_max < limit)
         limit = png_ptr->user_chunk_malloc_max;
@@ -2747,7 +2756,7 @@ png_cache_unknown_chunk(png_structrp png_ptr, png_uint_32 length)
      return 1;
   }
 }
-#endif /* READ_UNKNOWN_CHUNKS */
+#endif /* PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */

 /* Handle an unknown, or known but disabled, chunk */
 void /* PRIVATE */
@@ -2806,16 +2815,31 @@ png_handle_unknown(png_structrp png_ptr, png_inforp info_ptr,

            else if (ret == 0)
            {
-               /* Use the default handling, note that if there is per-chunk
-                * handling specified it has already been set into 'keep'.
+               /* If the keep value is 'default' or 'never' override it, but
+                * still error out on critical chunks unless the keep value is
+                * 'always'  While this is weird it is the behavior in 1.4.12.
+                * A possible improvement would be to obey the value set for the
+                * chunk, but this would be an API change that would probably
+                * damage some applications.
                *
-                * NOTE: this is an API change in 1.7.0. Prior to 1.7.0 libpng
-                * would force keep to PNG_HANDLE_CHUNK_IF_SAFE at this point,
-                * and 1.6.0 would issue a warning if this caused a default of
-                * discarding the chunk to be changed.
+                * The png_app_warning below catches the case that matters, where
+                * the application has not set specific save or ignore for this
+                * chunk or global save or ignore.
                */
-               if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT)
-                  keep = png_ptr->unknown_default;
+               if (keep < PNG_HANDLE_CHUNK_IF_SAFE)
+               {
+#                 ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+                     if (png_ptr->unknown_default < PNG_HANDLE_CHUNK_IF_SAFE)
+                     {
+                        png_chunk_warning(png_ptr, "Saving unknown chunk:");
+                        png_app_warning(png_ptr,
+                           "forcing save of an unhandled chunk;"
+                           " please call png_set_keep_unknown_chunks");
+                           /* with keep = PNG_HANDLE_CHUNK_IF_SAFE */
+                     }
+#                 endif
+                  keep = PNG_HANDLE_CHUNK_IF_SAFE;
+               }
            }

            else /* chunk was handled */
@@ -2832,7 +2856,7 @@ png_handle_unknown(png_structrp png_ptr, png_inforp info_ptr,

      else
         /* Use the SAVE_UNKNOWN_CHUNKS code or skip the chunk */
-#  endif /* READ_USER_CHUNKS */
+#  endif /* PNG_READ_USER_CHUNKS_SUPPORTED */

 #  ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
      {
@@ -2899,7 +2923,7 @@ png_handle_unknown(png_structrp png_ptr, png_inforp info_ptr,
               --(png_ptr->user_chunk_cache_max);
               /* FALL THROUGH */
            case 0: /* no limit */
-#     endif /* USER_LIMITS */
+#     endif /* PNG_USER_LIMITS_SUPPORTED */
               /* Here when the limit isn't reached or when limits are compiled
                * out; store the chunk.
                */
@@ -2923,12 +2947,12 @@ png_handle_unknown(png_structrp png_ptr, png_inforp info_ptr,
      png_free(png_ptr, png_ptr->unknown_chunk.data);
   png_ptr->unknown_chunk.data = NULL;

-#else /* !READ_UNKNOWN_CHUNKS */
+#else /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */
   /* There is no support to read an unknown chunk, so just skip it. */
   png_crc_finish(png_ptr, length);
   PNG_UNUSED(info_ptr)
   PNG_UNUSED(keep)
-#endif /* !READ_UNKNOWN_CHUNKS */
+#endif /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */

   /* Check for unhandled critical chunks */
   if (!handled && PNG_CHUNK_CRITICAL(png_ptr->chunk_name))
@@ -2977,7 +3001,7 @@ png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display)
 {
   unsigned int pixel_depth = png_ptr->transformed_pixel_depth;
   png_const_bytep sp = png_ptr->row_buf + 1;
-   png_alloc_size_t row_width = png_ptr->width;
+   png_uint_32 row_width = png_ptr->width;
   unsigned int pass = png_ptr->pass;
   png_bytep end_ptr = 0;
   png_byte end_byte = 0;
@@ -3159,13 +3183,13 @@ png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display)
            ((display)?display_mask[png][DEPTH_INDEX(depth)][pass>>1]:\
               row_mask[png][DEPTH_INDEX(depth)][pass])

-#else /* !USE_COMPILE_TIME_MASKS */
+#else /* !PNG_USE_COMPILE_TIME_MASKS */
         /* This is the runtime alternative: it seems unlikely that this will
          * ever be either smaller or faster than the compile time approach.
          */
 #        define MASK(pass,depth,display,png)\
            ((display)?B_MASK(pass,depth,png):S_MASK(pass,depth,png))
-#endif /* !USE_COMPILE_TIME_MASKS */
+#endif /* !PNG_USE_COMPILE_TIME_MASKS */

         /* Use the appropriate mask to copy the required bits.  In some cases
          * the byte mask will be 0 or 0xff; optimize these cases.  row_width is
@@ -3250,7 +3274,7 @@ png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display)

            /* But don't allow this number to exceed the actual row width. */
            if (bytes_to_copy > row_width)
-               bytes_to_copy = (unsigned int)/*SAFE*/row_width;
+               bytes_to_copy = row_width;
         }

         else /* normal row; Adam7 only ever gives us one pixel to copy. */
@@ -3307,7 +3331,7 @@ png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display)
               /* This can only be the RGB case, so each copy is exactly one
                * pixel and it is not necessary to check for a partial copy.
                */
-               for (;;)
+               for(;;)
               {
                  dp[0] = sp[0], dp[1] = sp[1], dp[2] = sp[2];

@@ -3416,7 +3440,7 @@ png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display)
                     return;
                  }
               }
-#endif /* ALIGN_ code */
+#endif /* PNG_ALIGN_ code */

               /* The true default - use a memcpy: */
               for (;;)
@@ -3430,7 +3454,7 @@ png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display)
                  dp += bytes_to_jump;
                  row_width -= bytes_to_jump;
                  if (bytes_to_copy > row_width)
-                     bytes_to_copy = (unsigned int)/*SAFE*/row_width;
+                     bytes_to_copy = row_width;
               }
         }

@@ -3440,7 +3464,7 @@ png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display)
      /* Here if pixel_depth < 8 to check 'end_ptr' below. */
   }
   else
-#endif
+#endif /* PNG_READ_INTERLACING_SUPPORTED */

   /* If here then the switch above wasn't used so just memcpy the whole row
    * from the temporary row buffer (notice that this overwrites the end of the
@@ -3696,7 +3720,7 @@ png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
   PNG_UNUSED(transformations)  /* Silence compiler warning */
 #endif
 }
-#endif /* READ_INTERLACING */
+#endif /* PNG_READ_INTERLACING_SUPPORTED */

 static void
 png_read_filter_row_sub(png_row_infop row_info, png_bytep row,
@@ -4090,7 +4114,6 @@ png_read_finish_IDAT(png_structrp png_ptr)
 void /* PRIVATE */
 png_read_finish_row(png_structrp png_ptr)
 {
-#ifdef PNG_READ_INTERLACING_SUPPORTED
   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */

   /* Start of interlace block */
@@ -4104,14 +4127,12 @@ png_read_finish_row(png_structrp png_ptr)

   /* Offset to next interlace block in the y direction */
   static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
-#endif /* READ_INTERLACING */

   png_debug(1, "in png_read_finish_row");
   png_ptr->row_number++;
   if (png_ptr->row_number < png_ptr->num_rows)
      return;

-#ifdef PNG_READ_INTERLACING_SUPPORTED
   if (png_ptr->interlaced)
   {
      png_ptr->row_number = 0;
@@ -4149,17 +4170,15 @@ png_read_finish_row(png_structrp png_ptr)
      if (png_ptr->pass < 7)
         return;
   }
-#endif /* READ_INTERLACING */

   /* Here after at the end of the last row of the last pass. */
   png_read_finish_IDAT(png_ptr);
 }
-#endif /* SEQUENTIAL_READ */
+#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */

 void /* PRIVATE */
 png_read_start_row(png_structrp png_ptr)
 {
-#ifdef PNG_READ_INTERLACING_SUPPORTED
   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */

   /* Start of interlace block */
@@ -4173,7 +4192,6 @@ png_read_start_row(png_structrp png_ptr)

   /* Offset to next interlace block in the y direction */
   static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
-#endif

   int max_pixel_depth;
   png_size_t row_bytes;
@@ -4183,7 +4201,6 @@ png_read_start_row(png_structrp png_ptr)
 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
   png_init_read_transformations(png_ptr);
 #endif
-#ifdef PNG_READ_INTERLACING_SUPPORTED
   if (png_ptr->interlaced)
   {
      if (!(png_ptr->transformations & PNG_INTERLACE))
@@ -4200,7 +4217,6 @@ png_read_start_row(png_structrp png_ptr)
   }

   else
-#endif /* READ_INTERLACING */
   {
      png_ptr->num_rows = png_ptr->height;
      png_ptr->iwidth = png_ptr->width;
@@ -4208,7 +4224,7 @@ png_read_start_row(png_structrp png_ptr)

   max_pixel_depth = png_ptr->pixel_depth;

-   /* WARNING: * png_read_transform_info (pngrtran.c) performs a simpler set of
+   /* WARNING: * png_read_transform_info (pngrtran.c) performs a simpliar set of
    * calculations to calculate the final pixel depth, then
    * png_do_read_transforms actually does the transforms.  This means that the
    * code which effectively calculates this value is actually repeated in three
@@ -4369,7 +4385,7 @@ defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
      png_error(png_ptr, "This image requires a row greater than 64KB");
 #endif

-   if (row_bytes + 48 > png_ptr->big_row_buf_size)
+   if (row_bytes + 48 > png_ptr->old_big_row_buf_size)
   {
     png_free(png_ptr, png_ptr->big_row_buf);
     png_free(png_ptr, png_ptr->big_prev_row);
@@ -4406,7 +4422,7 @@ defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
     png_ptr->row_buf = png_ptr->big_row_buf + 31;
     png_ptr->prev_row = png_ptr->big_prev_row + 31;
 #endif
-     png_ptr->big_row_buf_size = row_bytes + 48;
+     png_ptr->old_big_row_buf_size = row_bytes + 48;
   }

 #ifdef PNG_MAX_MALLOC_64K
@@ -4450,4 +4466,4 @@ defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)

   png_ptr->flags |= PNG_FLAG_ROW_INIT;
 }
-#endif /* READ */
+#endif /* PNG_READ_SUPPORTED */
--- a/pngset.c
+++ b/pngset.c
@@ -1,8 +1,8 @@

 /* pngset.c - storage of image information into info struct
 *
- * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.11 [June 5, 2014]
+ * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
@@ -59,7 +59,7 @@ png_set_cHRM_fixed(png_const_structrp png_ptr, png_inforp info_ptr,
   xy.whitey = white_y;

   if (png_colorspace_set_chromaticities(png_ptr, &info_ptr->colorspace, &xy,
-       2/* override with app values*/) != 0)
+      2/* override with app values*/))
      info_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;

   png_colorspace_sync_info(png_ptr, info_ptr);
@@ -90,8 +90,7 @@ png_set_cHRM_XYZ_fixed(png_const_structrp png_ptr, png_inforp info_ptr,
   XYZ.blue_Y = int_blue_Y;
   XYZ.blue_Z = int_blue_Z;

-   if (png_colorspace_set_endpoints(png_ptr, &info_ptr->colorspace,
-       &XYZ, 2) != 0)
+   if (png_colorspace_set_endpoints(png_ptr, &info_ptr->colorspace, &XYZ, 2))
      info_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;

   png_colorspace_sync_info(png_ptr, info_ptr);
@@ -130,9 +129,9 @@ png_set_cHRM_XYZ(png_const_structrp png_ptr, png_inforp info_ptr, double red_X,
      png_fixed(png_ptr, blue_Y, "cHRM Red Y"),
      png_fixed(png_ptr, blue_Z, "cHRM Red Z"));
 }
-#  endif /* FLOATING_POINT */
+#  endif /* PNG_FLOATING_POINT_SUPPORTED */

-#endif /* cHRM */
+#endif /* PNG_cHRM_SUPPORTED */

 #ifdef PNG_gAMA_SUPPORTED
 void PNGFAPI
@@ -190,7 +189,6 @@ png_set_hIST(png_const_structrp png_ptr, png_inforp info_ptr,
   if (info_ptr->hist == NULL)
   {
      png_warning(png_ptr, "Insufficient memory for hIST chunk data");
-
      return;
   }

@@ -229,13 +227,13 @@ png_set_IHDR(png_const_structrp png_ptr, png_inforp info_ptr,
   if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
      info_ptr->channels = 1;

-   else if ((info_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
+   else if (info_ptr->color_type & PNG_COLOR_MASK_COLOR)
      info_ptr->channels = 3;

   else
      info_ptr->channels = 1;

-   if ((info_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)
+   if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
      info_ptr->channels++;

   info_ptr->pixel_depth = (png_byte)(info_ptr->channels * info_ptr->bit_depth);
@@ -272,7 +270,7 @@ png_set_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,
   png_debug1(1, "in %s storage function", "pCAL");

   if (png_ptr == NULL || info_ptr == NULL || purpose == NULL || units == NULL
-       || (nparams > 0 && params == NULL))
+      || (nparams > 0 && params == NULL))
      return;

   length = strlen(purpose) + 1;
@@ -290,19 +288,16 @@ png_set_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,

   /* Validate params[nparams] */
   for (i=0; i<nparams; ++i)
-   {
      if (params[i] == NULL ||
-          !png_check_fp_string(params[i], strlen(params[i])))
+         !png_check_fp_string(params[i], strlen(params[i])))
         png_error(png_ptr, "Invalid format for pCAL parameter");
-   }

   info_ptr->pcal_purpose = png_voidcast(png_charp,
-       png_malloc_warn(png_ptr, length));
+      png_malloc_warn(png_ptr, length));

   if (info_ptr->pcal_purpose == NULL)
   {
      png_warning(png_ptr, "Insufficient memory for pCAL purpose");
-
      return;
   }

@@ -324,7 +319,6 @@ png_set_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,
   if (info_ptr->pcal_units == NULL)
   {
      png_warning(png_ptr, "Insufficient memory for pCAL units");
-
      return;
   }

@@ -336,7 +330,6 @@ png_set_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,
   if (info_ptr->pcal_params == NULL)
   {
      png_warning(png_ptr, "Insufficient memory for pCAL params");
-
      return;
   }

@@ -353,7 +346,6 @@ png_set_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,
      if (info_ptr->pcal_params[i] == NULL)
      {
         png_warning(png_ptr, "Insufficient memory for pCAL parameter");
-
         return;
      }

@@ -403,7 +395,6 @@ png_set_sCAL_s(png_const_structrp png_ptr, png_inforp info_ptr,
   if (info_ptr->scal_s_width == NULL)
   {
      png_warning(png_ptr, "Memory allocation failed while processing sCAL");
-
      return;
   }

@@ -422,7 +413,6 @@ png_set_sCAL_s(png_const_structrp png_ptr, png_inforp info_ptr,
      info_ptr->scal_s_width = NULL;

      png_warning(png_ptr, "Memory allocation failed while processing sCAL");
-
      return;
   }

@@ -432,8 +422,7 @@ png_set_sCAL_s(png_const_structrp png_ptr, png_inforp info_ptr,
   info_ptr->free_me |= PNG_FREE_SCAL;
 }

-#  if defined(PNG_FLOATING_POINT_SUPPORTED) &&\
-      defined(PNG_FLOATING_ARITHMETIC_SUPPORTED)
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
 void PNGAPI
 png_set_sCAL(png_const_structrp png_ptr, png_inforp info_ptr, int unit,
    double width, double height)
@@ -527,7 +516,6 @@ png_set_PLTE(png_structrp png_ptr, png_inforp info_ptr,
      else
      {
         png_warning(png_ptr, "Invalid palette length");
-
         return;
      }
   }
@@ -540,6 +528,7 @@ png_set_PLTE(png_structrp png_ptr, png_inforp info_ptr,
      ))
   {
      png_error(png_ptr, "Invalid palette");
+      return;
   }

   /* It may not actually be necessary to set png_ptr->palette here;
@@ -605,8 +594,7 @@ png_set_sRGB_gAMA_and_cHRM(png_const_structrp png_ptr, png_inforp info_ptr,
   if (png_ptr == NULL || info_ptr == NULL)
      return;

-   if (png_colorspace_set_sRGB(png_ptr, &info_ptr->colorspace,
-       srgb_intent) != 0)
+   if (png_colorspace_set_sRGB(png_ptr, &info_ptr->colorspace, srgb_intent))
   {
      /* This causes the gAMA and cHRM to be written too */
      info_ptr->colorspace.flags |=
@@ -663,7 +651,6 @@ png_set_iCCP(png_const_structrp png_ptr, png_inforp info_ptr,
   if (new_iccp_name == NULL)
   {
      png_benign_error(png_ptr, "Insufficient memory to process iCCP chunk");
-
      return;
   }

@@ -674,10 +661,8 @@ png_set_iCCP(png_const_structrp png_ptr, png_inforp info_ptr,
   if (new_iccp_profile == NULL)
   {
      png_free(png_ptr, new_iccp_name);
-      new_iccp_name = NULL;
      png_benign_error(png_ptr,
          "Insufficient memory to process iCCP profile");
-
      return;
   }

@@ -695,7 +680,7 @@ png_set_iCCP(png_const_structrp png_ptr, png_inforp info_ptr,

 #ifdef PNG_TEXT_SUPPORTED
 void PNGAPI
-png_set_text(png_structrp png_ptr, png_inforp info_ptr,
+png_set_text(png_const_structrp png_ptr, png_inforp info_ptr,
    png_const_textp text_ptr, int num_text)
 {
   int ret;
@@ -706,7 +691,7 @@ png_set_text(png_structrp png_ptr, png_inforp info_ptr,
 }

 int /* PRIVATE */
-png_set_text_2(png_structrp png_ptr, png_inforp info_ptr,
+png_set_text_2(png_const_structrp png_ptr, png_inforp info_ptr,
    png_const_textp text_ptr, int num_text)
 {
   int i;
@@ -741,7 +726,7 @@ png_set_text_2(png_structrp png_ptr, png_inforp info_ptr,
         else
            max_text = INT_MAX;

-         /* Now allocate a new array and copy the old members in; this does all
+         /* Now allocate a new array and copy the old members in, this does all
          * the overflow checks.
          */
         new_text = png_voidcast(png_textp,png_realloc_array(png_ptr,
@@ -753,7 +738,6 @@ png_set_text_2(png_structrp png_ptr, png_inforp info_ptr,
      {
         png_chunk_report(png_ptr, "too many text chunks",
            PNG_CHUNK_WRITE_ERROR);
-
         return 1;
      }

@@ -809,7 +793,7 @@ png_set_text_2(png_structrp png_ptr, png_inforp info_ptr,
         else
            lang_key_len = 0;
      }
-#  else /* iTXt */
+#  else /* PNG_iTXt_SUPPORTED */
      {
         png_chunk_report(png_ptr, "iTXt chunk not supported",
            PNG_CHUNK_WRITE_ERROR);
@@ -842,7 +826,6 @@ png_set_text_2(png_structrp png_ptr, png_inforp info_ptr,
      {
         png_chunk_report(png_ptr, "text chunk: out of memory",
               PNG_CHUNK_WRITE_ERROR);
-
         return 1;
      }

@@ -907,7 +890,7 @@ png_set_tIME(png_const_structrp png_ptr, png_inforp info_ptr,
   png_debug1(1, "in %s storage function", "tIME");

   if (png_ptr == NULL || info_ptr == NULL || mod_time == NULL ||
-       (png_ptr->mode & PNG_WROTE_tIME) != 0)
+       (png_ptr->mode & PNG_WROTE_tIME))
      return;

   if (mod_time->month == 0   || mod_time->month > 12  ||
@@ -916,7 +899,6 @@ png_set_tIME(png_const_structrp png_ptr, png_inforp info_ptr,
       mod_time->second > 60)
   {
      png_warning(png_ptr, "Ignoring invalid time value");
-
      return;
   }

@@ -935,97 +917,59 @@ png_set_tRNS(png_structrp png_ptr, png_inforp info_ptr,
   if (png_ptr == NULL || info_ptr == NULL)
      return;

-   if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
-      png_chunk_report(png_ptr,
-         "png_set_tRNS: invalid on PNG with alpha channel", PNG_CHUNK_ERROR);
-
-   else if (info_ptr->color_type & PNG_COLOR_MASK_PALETTE)
+   if (trans_alpha != NULL)
   {
-      int max_num;
+       /* It may not actually be necessary to set png_ptr->trans_alpha here;
+        * we do it for backward compatibility with the way the png_handle_tRNS
+        * function used to do the allocation.
+        *
+        * 1.6.0: The above statement is incorrect; png_handle_tRNS effectively
+        * relies on png_set_tRNS storing the information in png_struct
+        * (otherwise it won't be there for the code in pngrtran.c).
+        */

-      /* Free the old data; num_trans 0 can be used to kill the tRNS */
-      png_free_data(png_ptr, info_ptr, PNG_FREE_TRNS, 0);
+       png_free_data(png_ptr, info_ptr, PNG_FREE_TRNS, 0);

-      /* Do this just in case the old data was not owned by libpng: */
-      info_ptr->valid &= ~PNG_INFO_tRNS;
-      info_ptr->trans_alpha = NULL;
-      info_ptr->num_trans = 0;
+       /* Changed from num_trans to PNG_MAX_PALETTE_LENGTH in version 1.2.1 */
+       png_ptr->trans_alpha = info_ptr->trans_alpha = png_voidcast(png_bytep,
+         png_malloc(png_ptr, PNG_MAX_PALETTE_LENGTH));

-      /* Expect png_set_PLTE to happen before png_set_tRNS, so num_palette will
-       * be set, but this is not a requirement of the API.
-       */
-      if (png_ptr->num_palette)
-         max_num = png_ptr->num_palette;
-
-      else
-         max_num = 1 << png_ptr->bit_depth;
-
-      if (num_trans > max_num)
-      {
-         png_chunk_report(png_ptr, "png_set_tRNS: num_trans too large",
-            PNG_CHUNK_ERROR);
-         /* If control returns simply limit it; the behavior prior to 1.7 was to
-          * issue a warning and skip the palette in png_write_tRNS.
-          */
-         num_trans = max_num;
-      }
-
-      /* But only attempt a malloc if there is something to do; so the app can
-       * set a tRNS array then later delete it.
-       */
-      if (num_trans > 0 && trans_alpha != NULL)
-      {
-         /* Changed from num_trans to PNG_MAX_PALETTE_LENGTH in version 1.2.1,
-          * this avoids issues where a palette image contains out of range
-          * indices.
-          */
-         info_ptr->trans_alpha = png_voidcast(png_bytep, png_malloc(png_ptr,
-            PNG_MAX_PALETTE_LENGTH));
-         info_ptr->free_me |= PNG_FREE_TRNS;
-
-         memcpy(info_ptr->trans_alpha, trans_alpha,
-            (unsigned)/*SAFE*/num_trans);
-         info_ptr->valid |= PNG_INFO_tRNS;
-         info_ptr->num_trans = (png_uint_16)num_trans; /* SAFE */
-      }
+       if (num_trans > 0 && num_trans <= PNG_MAX_PALETTE_LENGTH)
+          memcpy(info_ptr->trans_alpha, trans_alpha, (png_size_t)num_trans);
   }

-   else /* not a PALETTE image */
+   if (trans_color != NULL)
   {
-      /* Invalidate any prior transparent color and set num_trans. It is not
-       * used internally in this case but png_get_tRNS still returns it.
-       */
-      info_ptr->valid &= ~PNG_INFO_tRNS;
-      info_ptr->num_trans = 0; /* for png_get_tRNS */
+      int sample_max = (1 << info_ptr->bit_depth);

-      if (trans_color != NULL && info_ptr->bit_depth < 16)
-      {
-         unsigned int sample_max = (1U << info_ptr->bit_depth) - 1U;
+      if ((info_ptr->color_type == PNG_COLOR_TYPE_GRAY &&
+          trans_color->gray > sample_max) ||
+          (info_ptr->color_type == PNG_COLOR_TYPE_RGB &&
+          (trans_color->red > sample_max ||
+          trans_color->green > sample_max ||
+          trans_color->blue > sample_max)))
+         png_warning(png_ptr,
+            "tRNS chunk has out-of-range samples for bit_depth");

-         if ((info_ptr->color_type == PNG_COLOR_TYPE_GRAY &&
-             trans_color->gray <= sample_max) ||
-             (info_ptr->color_type == PNG_COLOR_TYPE_RGB &&
-             trans_color->red <= sample_max &&
-             trans_color->green <= sample_max &&
-             trans_color->blue <= sample_max))
-         {
-            info_ptr->trans_color = *trans_color;
-            info_ptr->valid |= PNG_INFO_tRNS;
-            info_ptr->num_trans = 1; /* for png_get_tRNS */
-         }
+      info_ptr->trans_color = *trans_color;

-         else
-            png_chunk_report(png_ptr,
-               "tRNS chunk has out-of-range samples for bit_depth",
-               PNG_CHUNK_ERROR);
-      }
+      if (num_trans == 0)
+         num_trans = 1;
+   }
+
+   info_ptr->num_trans = (png_uint_16)num_trans;
+
+   if (num_trans != 0)
+   {
+      info_ptr->valid |= PNG_INFO_tRNS;
+      info_ptr->free_me |= PNG_FREE_TRNS;
   }
 }
 #endif

 #ifdef PNG_sPLT_SUPPORTED
 void PNGAPI
-png_set_sPLT(png_structrp png_ptr,
+png_set_sPLT(png_const_structrp png_ptr,
    png_inforp info_ptr, png_const_sPLT_tp entries, int nentries)
 /*
 *  entries        - array of png_sPLT_t structures
@@ -1052,7 +996,6 @@ png_set_sPLT(png_structrp png_ptr,
   {
      /* Out of memory or too many chunks */
      png_chunk_report(png_ptr, "too many sPLT chunks", PNG_CHUNK_WRITE_ERROR);
-
      return;
   }

@@ -1077,8 +1020,8 @@ png_set_sPLT(png_structrp png_ptr,

      np->depth = entries->depth;

-      /* In the event of out-of-memory just return - there's no point keeping
-       * on trying to add sPLT chunks.
+      /* In the even of out-of-memory just return - there's no point keeping on
+       * trying to add sPLT chunks.
       */
      length = strlen(entries->name) + 1;
      np->name = png_voidcast(png_charp, png_malloc_base(png_ptr, length));
@@ -1089,8 +1032,8 @@ png_set_sPLT(png_structrp png_ptr,
      memcpy(np->name, entries->name, length);

      /* IMPORTANT: we have memory now that won't get freed if something else
-       * goes wrong; this code must free it.  png_malloc_array produces no
-       * warnings; use a png_chunk_report (below) if there is an error.
+       * goes wrong, this code must free it.  png_malloc_array produces no
+       * warnings, use a png_chunk_report (below) if there is an error.
       */
      np->entries = png_voidcast(png_sPLT_entryp, png_malloc_array(png_ptr,
          entries->nentries, sizeof (png_sPLT_entry)));
@@ -1098,7 +1041,6 @@ png_set_sPLT(png_structrp png_ptr,
      if (np->entries == NULL)
      {
         png_free(png_ptr, np->name);
-         np->name = NULL;
         break;
      }

@@ -1121,7 +1063,7 @@ png_set_sPLT(png_structrp png_ptr,
   if (nentries > 0)
      png_chunk_report(png_ptr, "sPLT out of memory", PNG_CHUNK_WRITE_ERROR);
 }
-#endif /* sPLT */
+#endif /* PNG_sPLT_SUPPORTED */

 #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
 static png_byte
@@ -1130,10 +1072,10 @@ check_location(png_const_structrp png_ptr, int location)
   location &= (PNG_HAVE_IHDR|PNG_HAVE_PLTE|PNG_AFTER_IDAT);

   /* New in 1.6.0; copy the location and check it.  This is an API
-    * change; previously the app had to use the
+    * change, previously the app had to use the
    * png_set_unknown_chunk_location API below for each chunk.
    */
-   if (location == 0 && (png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
+   if (location == 0 && !(png_ptr->mode & PNG_IS_READ_STRUCT))
   {
      /* Write struct, so unknown chunks come from the app */
      png_app_warning(png_ptr,
@@ -1162,13 +1104,13 @@ check_location(png_const_structrp png_ptr, int location)
 }

 void PNGAPI
-png_set_unknown_chunks(png_structrp png_ptr,
+png_set_unknown_chunks(png_const_structrp png_ptr,
   png_inforp info_ptr, png_const_unknown_chunkp unknowns, int num_unknowns)
 {
   png_unknown_chunkp np;

   if (png_ptr == NULL || info_ptr == NULL || num_unknowns <= 0 ||
-       unknowns == NULL)
+      unknowns == NULL)
      return;

   /* Check for the failure cases where support has been disabled at compile
@@ -1179,19 +1121,17 @@ png_set_unknown_chunks(png_structrp png_ptr,
    */
 #  if !defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) && \
      defined(PNG_READ_SUPPORTED)
-      if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
+      if (png_ptr->mode & PNG_IS_READ_STRUCT)
      {
         png_app_error(png_ptr, "no unknown chunk support on read");
-
         return;
      }
 #  endif
 #  if !defined(PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED) && \
      defined(PNG_WRITE_SUPPORTED)
-      if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
+      if (!(png_ptr->mode & PNG_IS_READ_STRUCT))
      {
         png_app_error(png_ptr, "no unknown chunk support on write");
-
         return;
      }
 #  endif
@@ -1209,7 +1149,6 @@ png_set_unknown_chunks(png_structrp png_ptr,
   {
      png_chunk_report(png_ptr, "too many unknown chunks",
         PNG_CHUNK_WRITE_ERROR);
-
      return;
   }

@@ -1266,6 +1205,8 @@ png_set_unknown_chunk_location(png_const_structrp png_ptr, png_inforp info_ptr,
 {
   /* This API is pretty pointless in 1.6.0 because the location can be set
    * before the call to png_set_unknown_chunks.
+    *
+    * TODO: add a png_app_warning in 1.7
    */
   if (png_ptr != NULL && info_ptr != NULL && chunk >= 0 &&
      chunk < info_ptr->unknown_chunks_num)
@@ -1274,7 +1215,7 @@ png_set_unknown_chunk_location(png_const_structrp png_ptr, png_inforp info_ptr,
      {
         png_app_error(png_ptr, "invalid unknown chunk location");
         /* Fake out the pre 1.6.0 behavior: */
-         if ((location & PNG_HAVE_IDAT) != 0) /* undocumented! */
+         if ((location & PNG_HAVE_IDAT)) /* undocumented! */
            location = PNG_AFTER_IDAT;

         else
@@ -1284,10 +1225,6 @@ png_set_unknown_chunk_location(png_const_structrp png_ptr, png_inforp info_ptr,
      info_ptr->unknown_chunks[chunk].location =
         check_location(png_ptr, location);
   }
-
-   /* TODO: make this an error in 1.8 (or maybe it will become one in 1.7!) */
-   else if (png_ptr != NULL)
-      png_app_warning(png_ptr, "unknown chunk index out of range");
 }
 #endif

@@ -1316,14 +1253,10 @@ add_one_chunk(png_bytep list, unsigned int count, png_const_bytep add, int keep)
   /* Utility function: update the 'keep' state of a chunk if it is already in
    * the list, otherwise add it to the list.
    */
-   for (i=0; i<count; ++i, list += 5)
+   for (i=0; i<count; ++i, list += 5) if (memcmp(list, add, 4) == 0)
   {
-      if (memcmp(list, add, 4) == 0)
-      {
-         list[4] = (png_byte)keep;
-
-         return count;
-      }
+      list[4] = (png_byte)keep;
+      return count;
   }

   if (keep != PNG_HANDLE_CHUNK_AS_DEFAULT)
@@ -1349,7 +1282,6 @@ png_set_keep_unknown_chunks(png_structrp png_ptr, int keep,
   if (keep < 0 || keep >= PNG_HANDLE_CHUNK_LAST)
   {
      png_app_error(png_ptr, "png_set_keep_unknown_chunks: invalid keep");
-
      return;
   }

@@ -1388,7 +1320,7 @@ png_set_keep_unknown_chunks(png_structrp png_ptr, int keep,
      };

      chunk_list = chunks_to_ignore;
-      num_chunks = (unsigned int)/*SAFE*/(sizeof chunks_to_ignore)/5U;
+      num_chunks = (sizeof chunks_to_ignore)/5;
   }

   else /* num_chunks_in > 0 */
@@ -1399,7 +1331,6 @@ png_set_keep_unknown_chunks(png_structrp png_ptr, int keep,
          * which can be switched off.
          */
         png_app_error(png_ptr, "png_set_keep_unknown_chunks: no chunk list");
-
         return;
      }

@@ -1415,7 +1346,6 @@ png_set_keep_unknown_chunks(png_structrp png_ptr, int keep,
   if (num_chunks + old_num_chunks > UINT_MAX/5)
   {
      png_app_error(png_ptr, "png_set_keep_unknown_chunks: too many chunks");
-
      return;
   }

@@ -1450,15 +1380,12 @@ png_set_keep_unknown_chunks(png_structrp png_ptr, int keep,
      unsigned int i;

      for (i=0; i<num_chunks; ++i)
-      {
         old_num_chunks = add_one_chunk(new_list, old_num_chunks,
            chunk_list+5*i, keep);
-      }

      /* Now remove any spurious 'default' entries. */
      num_chunks = 0;
      for (i=0, inlist=outlist=new_list; i<old_num_chunks; ++i, inlist += 5)
-      {
         if (inlist[4])
         {
            if (outlist != inlist)
@@ -1466,7 +1393,6 @@ png_set_keep_unknown_chunks(png_structrp png_ptr, int keep,
            outlist += 5;
            ++num_chunks;
         }
-      }

      /* This means the application has removed all the specialized handling. */
      if (num_chunks == 0)
@@ -1518,8 +1444,7 @@ png_set_rows(png_const_structrp png_ptr, png_inforp info_ptr,
   if (png_ptr == NULL || info_ptr == NULL)
      return;

-   if (info_ptr->row_pointers != NULL &&
-       (info_ptr->row_pointers != row_pointers))
+   if (info_ptr->row_pointers && (info_ptr->row_pointers != row_pointers))
      png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);

   info_ptr->row_pointers = row_pointers;
@@ -1539,7 +1464,7 @@ png_set_compression_buffer_size(png_structrp png_ptr, png_size_t size)
       png_error(png_ptr, "invalid compression buffer size");

 #  ifdef PNG_SEQUENTIAL_READ_SUPPORTED
-      if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
+      if (png_ptr->mode & PNG_IS_READ_STRUCT)
      {
         png_ptr->IDAT_read_size = (png_uint_32)size; /* checked above */
         return;
@@ -1547,33 +1472,29 @@ png_set_compression_buffer_size(png_structrp png_ptr, png_size_t size)
 #  endif

 #  ifdef PNG_WRITE_SUPPORTED
-      if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
+      if (!(png_ptr->mode & PNG_IS_READ_STRUCT))
      {
         if (png_ptr->zowner != 0)
         {
            png_warning(png_ptr,
              "Compression buffer size cannot be changed because it is in use");
-
            return;
         }

-#ifndef __COVERITY__
         if (size > ZLIB_IO_MAX)
         {
            png_warning(png_ptr,
               "Compression buffer size limited to system maximum");
            size = ZLIB_IO_MAX; /* must fit */
         }
-#endif

-         if (size < 6)
+         else if (size < 6)
         {
            /* Deflate will potentially go into an infinite loop on a SYNC_FLUSH
             * if this is permitted.
             */
            png_warning(png_ptr,
               "Compression buffer size cannot be reduced below 6");
-
            return;
         }

@@ -1589,7 +1510,7 @@ png_set_compression_buffer_size(png_structrp png_ptr, png_size_t size)
 void PNGAPI
 png_set_invalid(png_const_structrp png_ptr, png_inforp info_ptr, int mask)
 {
-   if (png_ptr != NULL && info_ptr != NULL)
+   if (png_ptr && info_ptr)
      info_ptr->valid &= ~mask;
 }

@@ -1615,8 +1536,8 @@ png_set_user_limits (png_structrp png_ptr, png_uint_32 user_width_max,
 void PNGAPI
 png_set_chunk_cache_max (png_structrp png_ptr, png_uint_32 user_chunk_cache_max)
 {
-   if (png_ptr != NULL)
-      png_ptr->user_chunk_cache_max = user_chunk_cache_max;
+    if (png_ptr != NULL)
+       png_ptr->user_chunk_cache_max = user_chunk_cache_max;
 }

 /* This function was added to libpng 1.4.1 */
@@ -1627,7 +1548,7 @@ png_set_chunk_malloc_max (png_structrp png_ptr,
   if (png_ptr != NULL)
      png_ptr->user_chunk_malloc_max = user_chunk_malloc_max;
 }
-#endif /* ?SET_USER_LIMITS */
+#endif /* ?PNG_SET_USER_LIMITS_SUPPORTED */


 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
@@ -1650,14 +1571,14 @@ png_set_benign_errors(png_structrp png_ptr, int allowed)
      png_ptr->flags &= ~(PNG_FLAG_BENIGN_ERRORS_WARN |
         PNG_FLAG_APP_WARNINGS_WARN | PNG_FLAG_APP_ERRORS_WARN);
 }
-#endif /* BENIGN_ERRORS */
+#endif /* PNG_BENIGN_ERRORS_SUPPORTED */

 #ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
   /* Whether to report invalid palette index; added at libng-1.5.10.
    * It is possible for an indexed (color-type==3) PNG file to contain
    * pixels with invalid (out-of-range) indexes if the PLTE chunk has
    * fewer entries than the image's bit-depth would allow. We recover
-    * from this gracefully by filling any incomplete palette with zeros
+    * from this gracefully by filling any incomplete palette with zeroes
    * (opaque black).  By default, when this occurs libpng will issue
    * a benign error.  This API can be used to override that behavior.
    */
@@ -1673,4 +1594,4 @@ png_set_check_for_invalid_index(png_structrp png_ptr, int allowed)
      png_ptr->num_palette_max = -1;
 }
 #endif
-#endif /* READ || WRITE */
+#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
--- a/pngstruct.h
+++ b/pngstruct.h
@@ -1,11 +1,12 @@

 /* pngstruct.h - header file for PNG reference library
 *
- * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2013 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
+ * Last changed in libpng 1.6.1 [March 28, 2013]
+ *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
 * and license in png.h
@@ -27,9 +28,7 @@
   /* We must ensure that zlib uses 'const' in declarations. */
 #  define ZLIB_CONST
 #endif
-
-#include PNG_ZLIB_HEADER
-
+#include "zlib.h"
 #ifdef const
   /* zlib.h sometimes #defines const to nothing, undo this. */
 #  undef const
@@ -49,10 +48,10 @@
 /* zlib.h declares a magic type 'uInt' that limits the amount of data that zlib
 * can handle at once.  This type need be no larger than 16 bits (so maximum of
 * 65535), this define allows us to discover how big it is, but limited by the
- * maximum for size_t. The value can be overridden in a library build (pngusr.h,
- * or set it in CPPFLAGS) and it works to set it to a considerably lower value
- * (e.g. 255 works).  A lower value may help memory usage (slightly) and may
- * even improve performance on some systems (and degrade it on others.)
+ * maximuum for png_size_t.  The value can be overriden in a library build
+ * (pngusr.h, or set it in CPPFLAGS) and it works to set it to a considerably
+ * lower value (e.g. 255 works).  A lower value may help memory usage (slightly)
+ * and may even improve performance on some systems (and degrade it on others.)
 */
 #ifndef ZLIB_IO_MAX
 #  define ZLIB_IO_MAX ((uInt)-1)
@@ -102,7 +101,7 @@ typedef struct png_XYZ
 #endif /* COLORSPACE */

 #if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED)
-/* A colorspace is all the above plus, potentially, profile information;
+/* A colorspace is all the above plus, potentially, profile information,
 * however at present libpng does not use the profile internally so it is only
 * stored in the png_info struct (if iCCP is supported.)  The rendering intent
 * is retained here and is checked.
@@ -138,365 +137,224 @@ typedef const png_colorspace * PNG_RESTRICT png_const_colorspacerp;
 #define PNG_COLORSPACE_FROM_sRGB            0x0020
 #define PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB 0x0040
 #define PNG_COLORSPACE_MATCHES_sRGB         0x0080 /* exact match on profile */
-#define PNG_COLORSPACE_RGB_TO_GRAY_SET      0x0100 /* user specified coeffs */
 #define PNG_COLORSPACE_INVALID              0x8000
 #define PNG_COLORSPACE_CANCEL(flags)        (0xffff ^ (flags))
 #endif /* COLORSPACE || GAMMA */

 struct png_struct_def
 {
-   /* Rearranged in libpng 1.7 to attempt to lessen padding; in general
-    * (char), (short), (int) and pointer types are kept separate; however
-    * associated members under the control of the same #define are still
-    * together.
-    */
 #ifdef PNG_SETJMP_SUPPORTED
-   /* jmp_buf can have very high alignment requirements on some systems, so put
-    * it first (the other setjmp members are later as they are infrequently
-    * accessed.)
-    */
-   jmp_buf jmp_buf_local;
+   jmp_buf jmp_buf_local;     /* New name in 1.6.0 for jmp_buf in png_struct */
+   png_longjmp_ptr longjmp_fn;/* setjmp non-local goto function. */
+   jmp_buf *jmp_buf_ptr;      /* passed to longjmp_fn */
+   size_t jmp_buf_size;       /* size of the above, if allocated */
+#endif
+   png_error_ptr error_fn;    /* function for printing errors and aborting */
+#ifdef PNG_WARNINGS_SUPPORTED
+   png_error_ptr warning_fn;  /* function for printing warnings */
+#endif
+   png_voidp error_ptr;       /* user supplied struct for error functions */
+   png_rw_ptr write_data_fn;  /* function for writing output data */
+   png_rw_ptr read_data_fn;   /* function for reading input data */
+   png_voidp io_ptr;          /* ptr to application struct for I/O functions */
+
+#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
+   png_user_transform_ptr read_user_transform_fn; /* user read transform */
 #endif

-   /* Next the frequently accessed fields.  Many processors perform arithmetic
-    * in the address pipeline, but frequently the amount of addition or
-    * subtraction is limited.  By putting these fields at the head of png_struct
-    * the hope is that such processors will generate code that is both smaller
-    * and faster.
-    */
-   png_colorp  palette;        /* palette from the input file */
-   size_t      rowbytes;       /* size of row in bytes */
-   size_t      info_rowbytes;  /* cache of updated row bytes */
-   png_uint_32 width;          /* width of image in pixels */
-   png_uint_32 height;         /* height of image in pixels */
-   png_uint_32 num_rows;       /* number of rows in current pass */
-   png_uint_32 usr_width;      /* width of row at start of write */
-   png_uint_32 iwidth;         /* width of current interlaced row in pixels */
-   png_uint_32 row_number;     /* current row in interlace pass */
-   png_uint_32 chunk_name;     /* PNG_CHUNK() id of current chunk */
-   png_uint_32 crc;            /* current chunk CRC value */
-   png_uint_32 mode;           /* tells us where we are in the PNG file */
-   png_uint_32 flags;          /* flags indicating various things to libpng */
-   png_uint_32 transformations;/* which transformations to perform */
-   png_uint_32 zowner;         /* ID (chunk type) of zstream owner, 0 if none */
-   png_uint_32 free_me;        /* items libpng is responsible for freeing */
-
-   int         maximum_pixel_depth; /* pixel depth used for the row buffers */
-#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
-   int         num_palette_max;     /* maximum palette index found in IDAT */
+#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
+   png_user_transform_ptr write_user_transform_fn; /* user write transform */
 #endif

+/* These were added in libpng-1.0.2 */
+#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
+    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
+   png_voidp user_transform_ptr; /* user supplied struct for user transform */
+   png_byte user_transform_depth;    /* bit depth of user transformed pixels */
+   png_byte user_transform_channels; /* channels in user transformed pixels */
+#endif
+#endif
+
+   png_uint_32 mode;          /* tells us where we are in the PNG file */
+   png_uint_32 flags;         /* flags indicating various things to libpng */
+   png_uint_32 transformations; /* which transformations to perform */
+
+   png_uint_32 zowner;        /* ID (chunk type) of zstream owner, 0 if none */
+   z_stream    zstream;       /* decompression structure */
+
+#ifdef PNG_WRITE_SUPPORTED
+   png_compression_bufferp zbuffer_list; /* Created on demand during write */
+   uInt                    zbuffer_size; /* size of the actual buffer */
+
+   int zlib_level;            /* holds zlib compression level */
+   int zlib_method;           /* holds zlib compression method */
+   int zlib_window_bits;      /* holds zlib compression window bits */
+   int zlib_mem_level;        /* holds zlib compression memory level */
+   int zlib_strategy;         /* holds zlib compression strategy */
+#endif
+/* Added at libpng 1.5.4 */
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+   int zlib_text_level;            /* holds zlib compression level */
+   int zlib_text_method;           /* holds zlib compression method */
+   int zlib_text_window_bits;      /* holds zlib compression window bits */
+   int zlib_text_mem_level;        /* holds zlib compression memory level */
+   int zlib_text_strategy;         /* holds zlib compression strategy */
+#endif
+/* End of material added at libpng 1.5.4 */
+/* Added at libpng 1.6.0 */
+#ifdef PNG_WRITE_SUPPORTED
+   int zlib_set_level;        /* Actual values set into the zstream on write */
+   int zlib_set_method;
+   int zlib_set_window_bits;
+   int zlib_set_mem_level;
+   int zlib_set_strategy;
+#endif
+
+   png_uint_32 width;         /* width of image in pixels */
+   png_uint_32 height;        /* height of image in pixels */
+   png_uint_32 num_rows;      /* number of rows in current pass */
+   png_uint_32 usr_width;     /* width of row at start of write */
+   png_size_t rowbytes;       /* size of row in bytes */
+   png_uint_32 iwidth;        /* width of current interlaced row in pixels */
+   png_uint_32 row_number;    /* current row in interlace pass */
+   png_uint_32 chunk_name;    /* PNG_CHUNK() id of current chunk */
+   png_bytep prev_row;        /* buffer to save previous (unfiltered) row.
+                               * This is a pointer into big_prev_row
+                               */
+   png_bytep row_buf;         /* buffer to save current (unfiltered) row.
+                               * This is a pointer into big_row_buf
+                               */
+#ifdef PNG_WRITE_SUPPORTED
+   png_bytep sub_row;         /* buffer to save "sub" row when filtering */
+   png_bytep up_row;          /* buffer to save "up" row when filtering */
+   png_bytep avg_row;         /* buffer to save "avg" row when filtering */
+   png_bytep paeth_row;       /* buffer to save "Paeth" row when filtering */
+#endif
+   png_size_t info_rowbytes;  /* Added in 1.5.4: cache of updated row bytes */
+
+   png_uint_32 idat_size;     /* current IDAT size for read */
+   png_uint_32 crc;           /* current chunk CRC value */
+   png_colorp palette;        /* palette from the input file */
   png_uint_16 num_palette;   /* number of color entries in palette */
-   png_uint_16 num_trans;     /* number of transparency values */

-   /* Single byte values, typically used either to save space or to hold 1-byte
-    * values from the PNG chunk specifications.
-    */
-   png_byte compression_type; /* file compression type (always 0) */
+/* Added at libpng-1.5.10 */
+#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
+   int num_palette_max;       /* maximum palette index found in IDAT */
+#endif
+
+   png_uint_16 num_trans;     /* number of transparency values */
+   png_byte compression;      /* file compression type (always 0) */
   png_byte filter;           /* file filter type (always 0) */
   png_byte interlaced;       /* PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */
   png_byte pass;             /* current interlace pass (0 - 6) */
   png_byte do_filter;        /* row filter flags (see PNG_FILTER_ below ) */
   png_byte color_type;       /* color type of file */
   png_byte bit_depth;        /* bit depth of file */
+   png_byte usr_bit_depth;    /* bit depth of users row: write only */
   png_byte pixel_depth;      /* number of bits per pixel */
   png_byte channels;         /* number of channels in file */
+#ifdef PNG_WRITE_SUPPORTED
+   png_byte usr_channels;     /* channels at start of write: write only */
+#endif
   png_byte sig_bytes;        /* magic bytes read/written from start of file */
+   png_byte maximum_pixel_depth;
+                              /* pixel depth used for the row buffers */
   png_byte transformed_pixel_depth;
                              /* pixel depth after read/write transforms */
-
-   /* ERROR HANDLING */
-#ifdef PNG_SETJMP_SUPPORTED
-   jmp_buf        *jmp_buf_ptr;   /* passed to longjmp_fn */
-   png_longjmp_ptr longjmp_fn;    /* setjmp non-local goto function. */
-   size_t          jmp_buf_size;  /* size of *jmp_buf_ptr, if allocated */
+#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
+   png_uint_16 filler;           /* filler bytes for pixel expansion */
 #endif

-   /* Error/warning callbacks */
-   png_error_ptr error_fn;        /* print an error message and abort */
-#ifdef PNG_WARNINGS_SUPPORTED
-   png_error_ptr warning_fn;      /* print a warning and continue */
-#endif
-   png_voidp     error_ptr;       /* user supplied data for the above */
-
-   /* MEMORY ALLOCATION */
-#ifdef PNG_USER_MEM_SUPPORTED
-   png_malloc_ptr malloc_fn; /* allocate memory */
-   png_free_ptr   free_fn;   /* free memory */
-   png_voidp      mem_ptr;   /* user supplied data for the above */
-#endif
-
-   /* IO and BASIC READ/WRITE SUPPORT */
-   png_voidp            io_ptr;       /* user supplied data for IO callbacks */
-
-#ifdef PNG_READ_SUPPORTED
-   png_rw_ptr          read_data_fn;  /* read some bytes (must succeed) */
-   png_read_status_ptr read_row_fn;   /* called after each row is decoded */
-   png_bytep           read_buffer;   /* buffer for reading chunk data */
-
-   /* During read the following array is set up to point to the appropriate
-    * un-filter function, this allows per-image and per-processor optimization.
-    */
-   void (*read_filter[PNG_FILTER_VALUE_LAST-1])(png_row_infop row_info,
-      png_bytep row, png_const_bytep prev_row);
-
-#if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED)
-   /* The png_struct colorspace structure is only required on read - on write it
-    * is in (just) the info_struct.
-    */
-   png_colorspace   colorspace;
-#endif
-#endif /* READ */
-
-#ifdef PNG_SET_USER_LIMITS_SUPPORTED
-   png_uint_32 user_width_max;        /* Maximum width on read */
-   png_uint_32 user_height_max;       /* Maximum height on read */
-   /* Total memory that a single zTXt, sPLT, iTXt, iCCP, or unknown chunk
-    * can occupy when decompressed.  0 means unlimited.  This field is a counter
-    * - it is decremented as memory is allocated.
-    */
-   png_alloc_size_t user_chunk_malloc_max;
-#endif
-#ifdef PNG_USER_LIMITS_SUPPORTED
-   /* limit on total *number* of sPLT, text and unknown chunks that can be
-    * stored.  0 means unlimited.  This field is a counter - it is decremented
-    * as chunks are encountered.
-    */
-   png_uint_32 user_chunk_cache_max;
-#endif
-
-   /* The progressive reader gets passed data and calls application handling
-    * functions when appropriate.
-    */
-#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
-   png_progressive_info_ptr info_fn; /* called after header data fully read */
-   png_progressive_row_ptr  row_fn;  /* called after a row is decoded */
-   png_progressive_end_ptr  end_fn;  /* called after image is complete */
-
-   /* Progressive read control data */
-   png_bytep   save_buffer_ptr;      /* current location in save_buffer */
-   png_bytep   save_buffer;          /* buffer for previously read data */
-   png_bytep   current_buffer_ptr;   /* current location in current_buffer */
-   png_bytep   current_buffer;       /* buffer for recently used data */
-
-   size_t      save_buffer_size;     /* amount of data now in save_buffer */
-   size_t      save_buffer_max;      /* total size of save_buffer */
-   size_t      buffer_size;          /* total amount of available input data */
-   size_t      current_buffer_size;  /* amount of data now in current_buffer */
-
-   png_uint_32 push_length;          /* size of current input chunk */
-   png_uint_32 skip_length;          /* bytes to skip in input data */
-
-   int         process_mode;         /* what push library is currently doing */
-   int         cur_palette;          /* current push library palette index */
-#endif
-
-#ifdef PNG_WRITE_SUPPORTED
-   png_rw_ptr              write_data_fn;/* write some bytes (must succeed) */
-   png_write_status_ptr    write_row_fn; /* called after each row is encoded */
+#if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
+   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+   png_byte background_gamma_type;
+   png_fixed_point background_gamma;
+   png_color_16 background;   /* background color in screen gamma space */
+#ifdef PNG_READ_GAMMA_SUPPORTED
+   png_color_16 background_1; /* background normalized to gamma 1.0 */
 #endif
+#endif /* PNG_bKGD_SUPPORTED */

 #ifdef PNG_WRITE_FLUSH_SUPPORTED
   png_flush_ptr output_flush_fn; /* Function for flushing output */
-   png_uint_32   flush_dist; /* how many rows apart to flush, 0 - no flush */
-   png_uint_32   flush_rows; /* number of rows written since last flush */
+   png_uint_32 flush_dist;    /* how many rows apart to flush, 0 - no flush */
+   png_uint_32 flush_rows;    /* number of rows written since last flush */
 #endif

-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-   png_bytep    prev_filters;        /* filter type(s) of previous row(s) */
-   png_uint_16p filter_weights;      /* weight(s) for previous line(s) */
-   png_uint_16p inv_filter_weights;  /* 1/weight(s) for previous line(s) */
-   png_uint_16p filter_costs;        /* relative filter calculation cost */
-   png_uint_16p inv_filter_costs;    /* 1/relative filter calculation cost */
-   png_byte     heuristic_method;    /* heuristic for row filter selection */
-   png_byte     num_prev_filters;    /* number of weights for previous rows */
-#endif
-
-#ifdef PNG_WRITE_SUPPORTED
-   png_byte     usr_bit_depth;       /* bit depth of users row */
-   png_byte     usr_channels;        /* channels at start of write */
-#endif
-
-#ifdef PNG_IO_STATE_SUPPORTED
-   png_uint_32          io_state;     /* tells the app read/write progress */
-#endif
-
-   /* ROW BUFFERS
-    *
-    * Members that hold pointers to the decompressed image rows.
-    */
-   png_bytep row_buf;  /* buffer for the current (unfiltered) row */
-#if defined(PNG_WRITE_FILTER_SUPPORTED) || defined(PNG_READ_SUPPORTED)
-   png_bytep prev_row; /* buffer to save the previous (unfiltered) row */
-#endif
-
-#ifdef PNG_READ_SUPPORTED
-   /* The row_buf and prev_row pointers are misaligned so that the start of the
-    * row - after the filter byte - is aligned, the 'big_' pointers record the
-    * original allocated pointer.
-    */
-   png_bytep big_row_buf;
-   png_bytep big_prev_row;
-   size_t    big_row_buf_size; /* Actual size of both */
-#endif
-
-#ifdef PNG_WRITE_FILTER_SUPPORTED
-   png_bytep try_row;    /* buffer to save trial row when filtering */
-   png_bytep tst_row;    /* buffer to save best trial row when filtering */
-#endif
-
-   /* UNKNOWN CHUNK HANDLING */
-   /* TODO: this is excessively complicated, there are multiple ways of doing
-    * the same thing.  It should be cleaned up, possibly by finding out which
-    * APIs applications really use.
-    */
-#ifdef PNG_USER_CHUNKS_SUPPORTED
-   /* General purpose pointer for all user/unknown chunk handling; points to
-    * application supplied data for use in the read_user_chunk_fn callback
-    * (currently there is no write side support - the write side must use the
-    * set_unknown_chunks interface.)
-    */
-   png_voidp user_chunk_ptr;
-#endif
-
-#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
-   /* This is called back from the unknown chunk handling */
-   png_user_chunk_ptr     read_user_chunk_fn; /* user read chunk handler */
-#endif
-#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
-   /* Temporary storage for unknown chunk that the library doesn't recognize,
-    * used while reading the chunk.
-    */
-   png_unknown_chunk unknown_chunk;
-#endif
-
-#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
-   png_bytep    chunk_list;      /* List of png_byte[5]; the textual chunk name
-                                  * followed by a PNG_HANDLE_* byte */
-   int          unknown_default; /* As PNG_HANDLE_* */
-   unsigned int num_chunk_list;  /* Number of entries in the list */
-#endif
-
-   /* USER TRANSFORM SUPPORT */
-#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
-   png_user_transform_ptr read_user_transform_fn; /* user read transform */
-#endif
-#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
-   png_user_transform_ptr write_user_transform_fn; /* user write transform */
-#endif
-#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
-   png_voidp user_transform_ptr;      /* user supplied data for the above */
-   png_byte  user_transform_depth;    /* bit depth of user transformed pixels */
-   png_byte  user_transform_channels; /* channels in user transformed pixels */
-#endif
-
-   /* READ TRANSFORM SUPPORT
-    *
-    * Quite a lot of things can be done to the original image data on read, and
-    * most of these are configurable.  The data required by the configurable
-    * read transforms should be stored here.  The png_color_16 and png_color_8
-    * structures have low alignment requirements and odd sizes, so may cause
-    * misalignment when present.  Member alignment is as follows:
-    *
-    *    png_color_16   png_uint_16
-    *    png_color_8    png_byte
-    */
-   /* GAMMA/BACKGROUND/ALPHA-MODE/RGB-TO-GRAY/tRNS/sBIT
-    *
-    * These things are all interrelated because they need some or all of the
-    * gamma tables.  Some attempt has been made below to order these members by
-    * size, so that as little padding as possible is required.
-    */
-#ifdef PNG_READ_GAMMA_SUPPORTED
-   png_bytep gamma_table;        /* gamma table for 8-bit depth files */
-   png_uint_16p gamma_16_table;  /* gamma table for 16-bit depth files */
-
-#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
-   defined(PNG_READ_ALPHA_MODE_SUPPORTED) ||\
-   defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
-   png_bytep gamma_from_1;       /* converts from 1.0 to screen */
-   png_uint_16p gamma_to_1;      /* converts from file to 1.0 */
-   png_uint_16p gamma_16_from_1; /* converts from 1.0 to screen */
-   png_uint_16p gamma_16_to_1;   /* converts from file to 1.0 */
-#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
-#endif /* READ_GAMMA */
-
-#if defined(PNG_READ_tRNS_SUPPORTED) || \
-   defined(PNG_READ_BACKGROUND_SUPPORTED) || \
-   defined(PNG_READ_EXPAND_SUPPORTED)
-   png_bytep trans_alpha;           /* alpha values for paletted files */
-#endif
-
-   /* Integer values */
-#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
-   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
-   png_fixed_point background_gamma;
-#endif
 #ifdef PNG_READ_GAMMA_SUPPORTED
+   int gamma_shift;      /* number of "insignificant" bits in 16-bit gamma */
   png_fixed_point screen_gamma; /* screen gamma value (display_exponent) */
-   int gamma_shift; /* number of "insignificant" bits in 16-bit gamma */
+
+   png_bytep gamma_table;     /* gamma table for 8-bit depth files */
+   png_uint_16pp gamma_16_table; /* gamma table for 16-bit depth files */
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+   defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
+   defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+   png_bytep gamma_from_1;    /* converts from 1.0 to screen */
+   png_bytep gamma_to_1;      /* converts from file to 1.0 */
+   png_uint_16pp gamma_16_from_1; /* converts from 1.0 to screen */
+   png_uint_16pp gamma_16_to_1; /* converts from file to 1.0 */
+#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
 #endif

-   /* png_color_16 */
-#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
-   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
-   png_color_16 background;   /* background color in screen gamma space */
-   png_color_16 background_1; /* background normalized to gamma 1.0 */
-#endif
-#if defined(PNG_READ_tRNS_SUPPORTED) || \
-   defined(PNG_READ_BACKGROUND_SUPPORTED) || \
-   defined(PNG_READ_EXPAND_SUPPORTED)
-   png_color_16 trans_color;  /* transparent color for non-paletted files */
-#endif
-
-   /* png_uint_16 */
-#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
-   png_uint_16 rgb_to_gray_red_coeff;
-   png_uint_16 rgb_to_gray_green_coeff;
-   /* The blue coefficient is calculated from the above */
-#endif
-
-   /* png_color_8 */
-#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_sBIT_SUPPORTED)
+#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_sBIT_SUPPORTED)
   png_color_8 sig_bit;       /* significant bits in each available channel */
 #endif

-   /* png_byte */
-#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
-   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
-   png_byte background_gamma_type;
-#endif
-#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
-   png_byte rgb_to_gray_status;
-#endif
-
-   /* SHIFT - both READ_SHIFT and WRITE_SHIFT */
 #if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
   png_color_8 shift;         /* shift for significant bit tranformation */
 #endif

-   /* FILLER SUPPORT (pixel expansion or read, contraction on write) */
-#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
-   png_uint_16 filler;              /* filler bytes for pixel expansion */
+#if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) \
+ || defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
+   png_bytep trans_alpha;           /* alpha values for paletted files */
+   png_color_16 trans_color;  /* transparent color for non-paletted files */
+#endif
+
+   png_read_status_ptr read_row_fn;   /* called after each row is decoded */
+   png_write_status_ptr write_row_fn; /* called after each row is encoded */
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+   png_progressive_info_ptr info_fn; /* called after header data fully read */
+   png_progressive_row_ptr row_fn;   /* called after a prog. row is decoded */
+   png_progressive_end_ptr end_fn;   /* called after image is complete */
+   png_bytep save_buffer_ptr;        /* current location in save_buffer */
+   png_bytep save_buffer;            /* buffer for previously read data */
+   png_bytep current_buffer_ptr;     /* current location in current_buffer */
+   png_bytep current_buffer;         /* buffer for recently used data */
+   png_uint_32 push_length;          /* size of current input chunk */
+   png_uint_32 skip_length;          /* bytes to skip in input data */
+   png_size_t save_buffer_size;      /* amount of data now in save_buffer */
+   png_size_t save_buffer_max;       /* total size of save_buffer */
+   png_size_t buffer_size;           /* total amount of available input data */
+   png_size_t current_buffer_size;   /* amount of data now in current_buffer */
+   int process_mode;                 /* what push library is currently doing */
+   int cur_palette;                  /* current push library palette index */
+
+#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
+
+#if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
+/* For the Borland special 64K segment handler */
+   png_bytepp offset_table_ptr;
+   png_bytep offset_table;
+   png_uint_16 offset_table_number;
+   png_uint_16 offset_table_count;
+   png_uint_16 offset_table_count_free;
 #endif

-   /* QUANTIZE (convert to color-mapped) */
 #ifdef PNG_READ_QUANTIZE_SUPPORTED
-   png_bytep palette_lookup;   /* lookup table for quantizing */
-   png_bytep quantize_index;   /* index translation for palette files */
-   png_bytep quantize_sort;    /* working sort array */
-   png_bytep index_to_palette; /* where the original index currently is in the
-                                * palette
-                                */
-   png_bytep palette_to_index; /* which original index points to this palette
-                                * color
-                                */
+   png_bytep palette_lookup; /* lookup table for quantizing */
+   png_bytep quantize_index; /* index translation for palette files */
 #endif

-   /* MNG SUPPORT */
-#ifdef PNG_MNG_FEATURES_SUPPORTED
-   png_uint_32 mng_features_permitted;
-   png_byte filter_type;
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+   png_byte heuristic_method;        /* heuristic for row filter selection */
+   png_byte num_prev_filters;        /* number of weights for previous rows */
+   png_bytep prev_filters;           /* filter type(s) of previous row(s) */
+   png_uint_16p filter_weights;      /* weight(s) for previous line(s) */
+   png_uint_16p inv_filter_weights;  /* 1/weight(s) for previous line(s) */
+   png_uint_16p filter_costs;        /* relative filter calculation cost */
+   png_uint_16p inv_filter_costs;    /* 1/relative filter calculation cost */
 #endif

   /* Options */
@@ -504,48 +362,128 @@ struct png_struct_def
   png_byte options;           /* On/off state (up to 4 options) */
 #endif

-   /* COMPRESSION AND DECOMPRESSION SUPPORT.
-    *
-    * zlib expects a 'zstream' as the fundamental control structure, it allows
-    * all the parameters to be passed as one pointer.
+#if PNG_LIBPNG_VER < 10700
+/* To do: remove this from libpng-1.7 */
+#ifdef PNG_TIME_RFC1123_SUPPORTED
+   char time_buffer[29]; /* String to hold RFC 1123 time text */
+#endif
+#endif
+
+/* New members added in libpng-1.0.6 */
+
+   png_uint_32 free_me;    /* flags items libpng is responsible for freeing */
+
+#ifdef PNG_USER_CHUNKS_SUPPORTED
+   png_voidp user_chunk_ptr;
+#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+   png_user_chunk_ptr read_user_chunk_fn; /* user read chunk handler */
+#endif
+#endif
+
+#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+   int          unknown_default; /* As PNG_HANDLE_* */
+   unsigned int num_chunk_list;  /* Number of entries in the list */
+   png_bytep    chunk_list;      /* List of png_byte[5]; the textual chunk name
+                                  * followed by a PNG_HANDLE_* byte */
+#endif
+
+/* New members added in libpng-1.0.3 */
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+   png_byte rgb_to_gray_status;
+   /* Added in libpng 1.5.5 to record setting of coefficients: */
+   png_byte rgb_to_gray_coefficients_set;
+   /* These were changed from png_byte in libpng-1.0.6 */
+   png_uint_16 rgb_to_gray_red_coeff;
+   png_uint_16 rgb_to_gray_green_coeff;
+   /* deleted in 1.5.5: rgb_to_gray_blue_coeff; */
+#endif
+
+/* New member added in libpng-1.0.4 (renamed in 1.0.9) */
+#if defined(PNG_MNG_FEATURES_SUPPORTED)
+/* Changed from png_byte to png_uint_32 at version 1.2.0 */
+   png_uint_32 mng_features_permitted;
+#endif
+
+/* New member added in libpng-1.0.9, ifdef'ed out in 1.0.12, enabled in 1.2.0 */
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+   png_byte filter_type;
+#endif
+
+/* New members added in libpng-1.2.0 */
+
+/* New members added in libpng-1.0.2 but first enabled by default in 1.2.0 */
+#ifdef PNG_USER_MEM_SUPPORTED
+   png_voidp mem_ptr;             /* user supplied struct for mem functions */
+   png_malloc_ptr malloc_fn;      /* function for allocating memory */
+   png_free_ptr free_fn;          /* function for freeing memory */
+#endif
+
+/* New member added in libpng-1.0.13 and 1.2.0 */
+   png_bytep big_row_buf;         /* buffer to save current (unfiltered) row */
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+/* The following three members were added at version 1.0.14 and 1.2.4 */
+   png_bytep quantize_sort;          /* working sort array */
+   png_bytep index_to_palette;       /* where the original index currently is
+                                        in the palette */
+   png_bytep palette_to_index;       /* which original index points to this
+                                         palette color */
+#endif
+
+/* New members added in libpng-1.0.16 and 1.2.6 */
+   png_byte compression_type;
+
+#ifdef PNG_USER_LIMITS_SUPPORTED
+   png_uint_32 user_width_max;
+   png_uint_32 user_height_max;
+
+   /* Added in libpng-1.4.0: Total number of sPLT, text, and unknown
+    * chunks that can be stored (0 means unlimited).
    */
-   z_stream    zstream;       /* decompression structure */
+   png_uint_32 user_chunk_cache_max;
+
+   /* Total memory that a zTXt, sPLT, iTXt, iCCP, or unknown chunk
+    * can occupy when decompressed.  0 means unlimited.
+    */
+   png_alloc_size_t user_chunk_malloc_max;
+#endif
+
+/* New member added in libpng-1.0.25 and 1.2.17 */
+#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
+   /* Temporary storage for unknown chunk that the library doesn't recognize,
+    * used while reading the chunk.
+    */
+   png_unknown_chunk unknown_chunk;
+#endif
+
+/* New member added in libpng-1.2.26 */
+  png_size_t old_big_row_buf_size;

 #ifdef PNG_READ_SUPPORTED
-   /* These, and IDAT_read_size below, control how much input and output (at
-    * most) is available to zlib.
-    */
-   png_uint_32      idat_size;        /* current IDAT size for read */
-   png_alloc_size_t read_buffer_size; /* current size of the buffer */
+/* New member added in libpng-1.2.30 */
+  png_bytep        read_buffer;      /* buffer for reading chunk data */
+  png_alloc_size_t read_buffer_size; /* current size of the buffer */
 #endif
-
-#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
-   int zlib_text_level;       /* holds zlib compression level */
-   int zlib_text_method;      /* holds zlib compression method */
-   int zlib_text_window_bits; /* holds zlib compression window bits */
-   int zlib_text_mem_level;   /* holds zlib compression memory level */
-   int zlib_text_strategy;    /* holds zlib compression strategy */
-#endif
-
-#ifdef PNG_WRITE_SUPPORTED
-   int zlib_level;            /* holds zlib compression level */
-   int zlib_method;           /* holds zlib compression method */
-   int zlib_window_bits;      /* holds zlib compression window bits */
-   int zlib_mem_level;        /* holds zlib compression memory level */
-   int zlib_strategy;         /* holds zlib compression strategy */
-
-   int zlib_set_level;        /* Actual values set into the zstream on write */
-   int zlib_set_method;
-   int zlib_set_window_bits;
-   int zlib_set_mem_level;
-   int zlib_set_strategy;
-
-   png_compression_bufferp zbuffer_list; /* Created on demand during write */
-   uInt                    zbuffer_size; /* size of the actual zlib buffer */
-#endif
-
 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
-   uInt IDAT_read_size;       /* limit on read buffer size for IDAT */
+  uInt             IDAT_read_size;   /* limit on read buffer size for IDAT */
+#endif
+
+#ifdef PNG_IO_STATE_SUPPORTED
+/* New member added in libpng-1.4.0 */
+   png_uint_32 io_state;
+#endif
+
+/* New member added in libpng-1.5.6 */
+   png_bytep big_prev_row;
+
+/* New member added in libpng-1.5.7 */
+   void (*read_filter[PNG_FILTER_VALUE_LAST-1])(png_row_infop row_info,
+      png_bytep row, png_const_bytep prev_row);
+
+#ifdef PNG_READ_SUPPORTED
+#if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED)
+   png_colorspace   colorspace;
+#endif
 #endif
 };
 #endif /* PNGSTRUCT_H */
--- a/pngtest.c
+++ b/pngtest.c
@@ -1,8 +1,8 @@

 /* pngtest.c - a simple test program to test libpng
 *
- * Last changed in libpng 1.6.17 [(PENDING RELEASE)]
- * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.11 [June 5, 2014]
+ * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
@@ -283,8 +283,7 @@ count_zero_samples(png_structp png_ptr, png_row_infop row_info, png_bytep data)
       png_uint_32 n, nstop;
       int channel;
       int color_channels = row_info->channels;
-       if (row_info->color_type > 3)
-          color_channels--;
+       if (row_info->color_type > 3)color_channels--;

       for (n = 0, nstop=row_info->width; n<nstop; n++)
       {
@@ -311,7 +310,7 @@ count_zero_samples(png_structp png_ptr, png_row_infop row_info, png_bytep data)
       }
    }
 }
-#endif /* WRITE_USER_TRANSFORM */
+#endif /* PNG_WRITE_USER_TRANSFORM_SUPPORTED */

 #ifndef PNG_STDIO_SUPPORTED
 /* START of code to validate stdio-free compilation */
@@ -420,7 +419,7 @@ pngtest_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
   pngtest_check_io_state(png_ptr, length, PNG_IO_WRITING);
 #endif
 }
-#endif /* !STDIO */
+#endif /* !PNG_STDIO_SUPPORTED */

 /* This function is called when there is a warning, but the library thinks
 * it can continue anyway.  Replacement functions don't have to do anything
@@ -589,7 +588,7 @@ png_debug_free(png_structp png_ptr, png_voidp ptr)

         if (pinfo->next == NULL)
         {
-            fprintf(STDERR, "Pointer %p not found\n", ptr);
+            fprintf(STDERR, "Pointer %x not found\n", (unsigned int)ptr);
            break;
         }

@@ -605,7 +604,7 @@ png_debug_free(png_structp png_ptr, png_voidp ptr)
      free(ptr);
   ptr = NULL;
 }
-#endif /* USER_MEM && DEBUG */
+#endif /* PNG_USER_MEM_SUPPORTED && PNG_DEBUG */
 /* END of code to test memory allocation/deallocation */


@@ -644,16 +643,16 @@ set_location(png_structp png_ptr, struct user_chunk_data *data, int what)
 {
   int location;

-   if ((data->location[0] & what) != 0 || (data->location[1] & what) != 0)
+   if ((data->location[0] & what) || (data->location[1] & what))
      return 0; /* already have one of these */

-   /* Find where we are (the code below zeroes info_ptr to indicate that the
+   /* Find where we are (the code below zeros info_ptr to indicate that the
    * chunks before the first IDAT have been read.)
    */
   if (data->info_ptr == NULL) /* after IDAT */
      location = what | after_IDAT;

-   else if (png_get_valid(png_ptr, data->info_ptr, PNG_INFO_PLTE) != 0)
+   else if (png_get_valid(png_ptr, data->info_ptr, PNG_INFO_PLTE))
      location = what | before_IDAT;

   else
@@ -700,7 +699,7 @@ read_user_chunk_callback(png_struct *png_ptr, png_unknown_chunkp chunk)
         if (chunk->data[0] != 0 && chunk->data[0] != 1)
            return (-1);  /* Invalid mode */

-         if (set_location(png_ptr, my_user_chunk_data, have_sTER) != 0)
+         if (set_location(png_ptr, my_user_chunk_data, have_sTER))
         {
            my_user_chunk_data->sTER_mode=chunk->data[0];
            return (1);
@@ -719,7 +718,7 @@ read_user_chunk_callback(png_struct *png_ptr, png_unknown_chunkp chunk)
   if (chunk->size != 9)
      return (-1); /* Error return */

-   if (set_location(png_ptr, my_user_chunk_data, have_vpAg) == 0)
+   if (!set_location(png_ptr, my_user_chunk_data, have_vpAg))
      return (0);  /* duplicate vpAg */

   my_user_chunk_data->vpAg_width = png_get_uint_31(png_ptr, chunk->data);
@@ -780,8 +779,8 @@ write_chunks(png_structp write_ptr, int location)
         write_vpAg_chunk(write_ptr);
   }
 }
-#endif /* WRITE */
-#else /* !READ_USER_CHUNKS */
+#endif /* PNG_WRITE_SUPPORTED */
+#else /* !PNG_READ_USER_CHUNKS_SUPPORTED */
 #  define write_chunks(pp,loc) ((void)0)
 #endif
 /* END of code to demonstrate user chunk support */
@@ -1050,7 +1049,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      int interlace_type, compression_type, filter_type;

      if (png_get_IHDR(read_ptr, read_info_ptr, &width, &height, &bit_depth,
-          &color_type, &interlace_type, &compression_type, &filter_type) != 0)
+          &color_type, &interlace_type, &compression_type, &filter_type))
      {
         png_set_IHDR(write_ptr, write_info_ptr, width, height, bit_depth,
            color_type, interlace_type, compression_type, filter_type);
@@ -1083,7 +1082,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
         blue_y;

      if (png_get_cHRM_fixed(read_ptr, read_info_ptr, &white_x, &white_y,
-         &red_x, &red_y, &green_x, &green_y, &blue_x, &blue_y) != 0)
+         &red_x, &red_y, &green_x, &green_y, &blue_x, &blue_y))
      {
         png_set_cHRM_fixed(write_ptr, write_info_ptr, white_x, white_y, red_x,
            red_y, green_x, green_y, blue_x, blue_y);
@@ -1094,7 +1093,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
   {
      png_fixed_point gamma;

-      if (png_get_gAMA_fixed(read_ptr, read_info_ptr, &gamma) != 0)
+      if (png_get_gAMA_fixed(read_ptr, read_info_ptr, &gamma))
         png_set_gAMA_fixed(write_ptr, write_info_ptr, gamma);
   }
 #endif
@@ -1106,7 +1105,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
         blue_y;

      if (png_get_cHRM(read_ptr, read_info_ptr, &white_x, &white_y, &red_x,
-         &red_y, &green_x, &green_y, &blue_x, &blue_y) != 0)
+         &red_y, &green_x, &green_y, &blue_x, &blue_y))
      {
         png_set_cHRM(write_ptr, write_info_ptr, white_x, white_y, red_x,
            red_y, green_x, green_y, blue_x, blue_y);
@@ -1117,7 +1116,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
   {
      double gamma;

-      if (png_get_gAMA(read_ptr, read_info_ptr, &gamma) != 0)
+      if (png_get_gAMA(read_ptr, read_info_ptr, &gamma))
         png_set_gAMA(write_ptr, write_info_ptr, gamma);
   }
 #endif
@@ -1131,7 +1130,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      int compression_type;

      if (png_get_iCCP(read_ptr, read_info_ptr, &name, &compression_type,
-                      &profile, &proflen) != 0)
+                      &profile, &proflen))
      {
         png_set_iCCP(write_ptr, write_info_ptr, name, compression_type,
                      profile, proflen);
@@ -1142,7 +1141,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
   {
      int intent;

-      if (png_get_sRGB(read_ptr, read_info_ptr, &intent) != 0)
+      if (png_get_sRGB(read_ptr, read_info_ptr, &intent))
         png_set_sRGB(write_ptr, write_info_ptr, intent);
   }
 #endif
@@ -1150,14 +1149,14 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      png_colorp palette;
      int num_palette;

-      if (png_get_PLTE(read_ptr, read_info_ptr, &palette, &num_palette) != 0)
+      if (png_get_PLTE(read_ptr, read_info_ptr, &palette, &num_palette))
         png_set_PLTE(write_ptr, write_info_ptr, palette, num_palette);
   }
 #ifdef PNG_bKGD_SUPPORTED
   {
      png_color_16p background;

-      if (png_get_bKGD(read_ptr, read_info_ptr, &background) != 0)
+      if (png_get_bKGD(read_ptr, read_info_ptr, &background))
      {
         png_set_bKGD(write_ptr, write_info_ptr, background);
      }
@@ -1167,7 +1166,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
   {
      png_uint_16p hist;

-      if (png_get_hIST(read_ptr, read_info_ptr, &hist) != 0)
+      if (png_get_hIST(read_ptr, read_info_ptr, &hist))
         png_set_hIST(write_ptr, write_info_ptr, hist);
   }
 #endif
@@ -1177,7 +1176,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      int unit_type;

      if (png_get_oFFs(read_ptr, read_info_ptr, &offset_x, &offset_y,
-          &unit_type) != 0)
+          &unit_type))
      {
         png_set_oFFs(write_ptr, write_info_ptr, offset_x, offset_y, unit_type);
      }
@@ -1191,7 +1190,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      int type, nparams;

      if (png_get_pCAL(read_ptr, read_info_ptr, &purpose, &X0, &X1, &type,
-         &nparams, &units, &params) != 0)
+         &nparams, &units, &params))
      {
         png_set_pCAL(write_ptr, write_info_ptr, purpose, X0, X1, type,
            nparams, units, params);
@@ -1203,8 +1202,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      png_uint_32 res_x, res_y;
      int unit_type;

-      if (png_get_pHYs(read_ptr, read_info_ptr, &res_x, &res_y,
-          &unit_type) != 0)
+      if (png_get_pHYs(read_ptr, read_info_ptr, &res_x, &res_y, &unit_type))
         png_set_pHYs(write_ptr, write_info_ptr, res_x, res_y, unit_type);
   }
 #endif
@@ -1212,7 +1210,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
   {
      png_color_8p sig_bit;

-      if (png_get_sBIT(read_ptr, read_info_ptr, &sig_bit) != 0)
+      if (png_get_sBIT(read_ptr, read_info_ptr, &sig_bit))
         png_set_sBIT(write_ptr, write_info_ptr, sig_bit);
   }
 #endif
@@ -1224,7 +1222,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      double scal_width, scal_height;

      if (png_get_sCAL(read_ptr, read_info_ptr, &unit, &scal_width,
-         &scal_height) != 0)
+         &scal_height))
      {
         png_set_sCAL(write_ptr, write_info_ptr, unit, scal_width, scal_height);
      }
@@ -1236,7 +1234,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      png_charp scal_width, scal_height;

      if (png_get_sCAL_s(read_ptr, read_info_ptr, &unit, &scal_width,
-          &scal_height) != 0)
+          &scal_height))
      {
         png_set_sCAL_s(write_ptr, write_info_ptr, unit, scal_width,
             scal_height);
@@ -1276,11 +1274,11 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
   {
      png_timep mod_time;

-      if (png_get_tIME(read_ptr, read_info_ptr, &mod_time) != 0)
+      if (png_get_tIME(read_ptr, read_info_ptr, &mod_time))
      {
         png_set_tIME(write_ptr, write_info_ptr, mod_time);
 #ifdef PNG_TIME_RFC1123_SUPPORTED
-         if (png_convert_to_rfc1123_buffer(tIME_string, mod_time) != 0)
+         if (png_convert_to_rfc1123_buffer(tIME_string, mod_time))
            tIME_string[(sizeof tIME_string) - 1] = '\0';

         else
@@ -1290,7 +1288,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
         }

         tIME_chunk_present++;
-#endif /* TIME_RFC1123 */
+#endif /* PNG_TIME_RFC1123_SUPPORTED */
      }
   }
 #endif
@@ -1301,7 +1299,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      png_color_16p trans_color;

      if (png_get_tRNS(read_ptr, read_info_ptr, &trans_alpha, &num_trans,
-         &trans_color) != 0)
+         &trans_color))
      {
         int sample_max = (1 << bit_depth);
         /* libpng doesn't reject a tRNS chunk with out-of-range samples */
@@ -1384,12 +1382,11 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      {
 #ifndef SINGLE_ROWBUF_ALLOC
         pngtest_debug2("Allocating row buffer (pass %d, y = %u)...", pass, y);
-
         row_buf = (png_bytep)png_malloc(read_ptr,
            png_get_rowbytes(read_ptr, read_info_ptr));

-         pngtest_debug2("\t0x%08lx (%lu bytes)", (unsigned long)row_buf,
-            (unsigned long)png_get_rowbytes(read_ptr, read_info_ptr));
+         pngtest_debug2("\t0x%08lx (%u bytes)", (unsigned long)row_buf,
+            png_get_rowbytes(read_ptr, read_info_ptr));

 #endif /* !SINGLE_ROWBUF_ALLOC */
         png_read_rows(read_ptr, (png_bytepp)&row_buf, NULL, 1);
@@ -1406,7 +1403,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
         t_encode += (t_stop - t_start);
         t_start = t_stop;
 #endif
-#endif /* WRITE */
+#endif /* PNG_WRITE_SUPPORTED */

 #ifndef SINGLE_ROWBUF_ALLOC
         pngtest_debug2("Freeing row buffer (pass %d, y = %u)", pass, y);
@@ -1459,11 +1456,11 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
   {
      png_timep mod_time;

-      if (png_get_tIME(read_ptr, end_info_ptr, &mod_time) != 0)
+      if (png_get_tIME(read_ptr, end_info_ptr, &mod_time))
      {
         png_set_tIME(write_ptr, write_end_info_ptr, mod_time);
 #ifdef PNG_TIME_RFC1123_SUPPORTED
-         if (png_convert_to_rfc1123_buffer(tIME_string, mod_time) != 0)
+         if (png_convert_to_rfc1123_buffer(tIME_string, mod_time))
            tIME_string[(sizeof tIME_string) - 1] = '\0';

         else
@@ -1473,7 +1470,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
         }

         tIME_chunk_present++;
-#endif /* TIME_RFC1123 */
+#endif /* PNG_TIME_RFC1123_SUPPORTED */
      }
   }
 #endif
@@ -1678,7 +1675,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
         }
      }
   }
-#endif /* WRITE */
+#endif /* PNG_WRITE_SUPPORTED */

   FCLOSE(fpin);
   FCLOSE(fpout);
@@ -1701,8 +1698,6 @@ main(int argc, char *argv[])
   int multiple = 0;
   int ierror = 0;

-   png_structp dummy_ptr;
-
   fprintf(STDERR, "\n Testing libpng version %s\n", PNG_LIBPNG_VER_STRING);
   fprintf(STDERR, "   with zlib   version %s\n", ZLIB_VERSION);
   fprintf(STDERR, "%s", png_get_copyright(NULL));
@@ -1785,11 +1780,10 @@ main(int argc, char *argv[])
      }
   }

-   if (multiple == 0 && argc == 3 + verbose)
+   if (!multiple && argc == 3 + verbose)
     outname = argv[2 + verbose];

-   if ((multiple == 0 && argc > 3 + verbose) ||
-       (multiple != 0 && argc < 2))
+   if ((!multiple && argc > 3 + verbose) || (multiple && argc < 2))
   {
     fprintf(STDERR,
       "usage: %s [infile.png] [outfile.png]\n\t%s -m {infile.png}\n",
@@ -1811,9 +1805,6 @@ main(int argc, char *argv[])
      {
         int kerror;
         fprintf(STDERR, "\n Testing %s:", argv[i]);
-#if PNG_DEBUG > 0
-         fprintf(STDERR, "\n");
-#endif
         kerror = test_one_file(argv[i], outname);
         if (kerror == 0)
         {
@@ -1828,7 +1819,7 @@ main(int argc, char *argv[])
 #endif
 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
            for (k = 0; k<256; k++)
-               if (filters_used[k] != 0)
+               if (filters_used[k])
                  fprintf(STDERR, " Filter %d was used %lu times\n",
                     k, (unsigned long)filters_used[k]);
 #endif
@@ -1837,7 +1828,7 @@ main(int argc, char *argv[])
            fprintf(STDERR, " tIME = %s\n", tIME_string);

         tIME_chunk_present = 0;
-#endif /* TIME_RFC1123 */
+#endif /* PNG_TIME_RFC1123_SUPPORTED */
         }

         else
@@ -1859,9 +1850,9 @@ main(int argc, char *argv[])

            while (pinfo != NULL)
            {
-               fprintf(STDERR, " %lu bytes at %p\n",
+               fprintf(STDERR, " %lu bytes at %x\n",
                 (unsigned long)pinfo->size,
-                 pinfo->pointer);
+                 (unsigned int)pinfo->pointer);
               pinfo = pinfo->next;
            }
         }
@@ -1895,12 +1886,7 @@ main(int argc, char *argv[])
            status_dots_requested = 0;

         if (i == 0 || verbose == 1 || ierror != 0)
-         {
            fprintf(STDERR, "\n Testing %s:", inname);
-#if PNG_DEBUG > 0
-            fprintf(STDERR, "\n");
-#endif
-         }

         kerror = test_one_file(inname, outname);

@@ -1919,26 +1905,21 @@ main(int argc, char *argv[])
 #endif
 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
                for (k = 0; k<256; k++)
-                   if (filters_used[k] != 0)
+                   if (filters_used[k])
                      fprintf(STDERR, " Filter %d was used %lu times\n",
                         k, (unsigned long)filters_used[k]);
 #endif
 #ifdef PNG_TIME_RFC1123_SUPPORTED
             if (tIME_chunk_present != 0)
                fprintf(STDERR, " tIME = %s\n", tIME_string);
-#endif /* TIME_RFC1123 */
+#endif /* PNG_TIME_RFC1123_SUPPORTED */
            }
         }

         else
         {
            if (verbose == 0 && i != 2)
-            {
               fprintf(STDERR, "\n Testing %s:", inname);
-#if PNG_DEBUG > 0
-               fprintf(STDERR, "\n");
-#endif
-            }

            fprintf(STDERR, " FAIL\n");
            ierror += kerror;
@@ -1957,8 +1938,8 @@ main(int argc, char *argv[])

             while (pinfo != NULL)
             {
-                fprintf(STDERR, " %lu bytes at %p\n",
-                   (unsigned long)pinfo->size, pinfo->pointer);
+                fprintf(STDERR, " %lu bytes at %x\n",
+                   (unsigned long)pinfo->size, (unsigned int)pinfo->pointer);
                pinfo = pinfo->next;
             }
          }
@@ -1996,24 +1977,6 @@ main(int argc, char *argv[])
   else
      fprintf(STDERR, " libpng FAILS test\n");

-   dummy_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
-   fprintf(STDERR, " Default limits:\n");
-   fprintf(STDERR, "  width_max  = %lu\n",
-      (unsigned long) png_get_user_width_max(dummy_ptr));
-   fprintf(STDERR, "  height_max = %lu\n",
-      (unsigned long) png_get_user_height_max(dummy_ptr));
-   if (png_get_chunk_cache_max(dummy_ptr) == 0)
-      fprintf(STDERR, "  cache_max  = unlimited\n");
-   else
-      fprintf(STDERR, "  cache_max  = %lu\n",
-         (unsigned long) png_get_chunk_cache_max(dummy_ptr));
-   if (png_get_chunk_malloc_max(dummy_ptr) == 0)
-      fprintf(STDERR, "  malloc_max = unlimited\n");
-   else
-      fprintf(STDERR, "  malloc_max = %lu\n",
-         (unsigned long) png_get_chunk_malloc_max(dummy_ptr));
-   png_destroy_read_struct(&dummy_ptr, NULL, NULL);
-
   return (int)(ierror != 0);
 }
 #else
@@ -2028,4 +1991,4 @@ main(void)
 #endif

 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef png_libpng_version_1_7_0beta52 Your_png_h_is_not_version_1_7_0beta52;
+typedef png_libpng_version_1_6_13beta04 Your_png_h_is_not_version_1_6_13beta04;
--- a/pngtrans.c
+++ b/pngtrans.c
@@ -1,7 +1,7 @@

 /* pngtrans.c - transforms the data in a row (used by both readers and writers)
 *
- * Last changed in libpng 1.6.15 [November 20, 2014]
+ * Last changed in libpng 1.6.11 [June 5, 2014]
 * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -100,7 +100,7 @@ png_set_interlace_handling(png_structrp png_ptr)
 {
   png_debug(1, "in png_set_interlace handling");

-   if (png_ptr != 0 && png_ptr->interlaced != 0)
+   if (png_ptr && png_ptr->interlaced)
   {
      png_ptr->transformations |= PNG_INTERLACE;
      return (7);
@@ -127,7 +127,7 @@ png_set_filler(png_structrp png_ptr, png_uint_32 filler, int filler_loc)
   /* In libpng 1.6 it is possible to determine whether this is a read or write
    * operation and therefore to do more checking here for a valid call.
    */
-   if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
+   if (png_ptr->mode & PNG_IS_READ_STRUCT)
   {
 #     ifdef PNG_READ_FILLER_SUPPORTED
         /* On read png_set_filler is always valid, regardless of the base PNG
@@ -210,7 +210,7 @@ png_set_add_alpha(png_structrp png_ptr, png_uint_32 filler, int filler_loc)

   png_set_filler(png_ptr, filler, filler_loc);
   /* The above may fail to do anything. */
-   if ((png_ptr->transformations & PNG_FILLER) != 0)
+   if (png_ptr->transformations & PNG_FILLER)
      png_ptr->transformations |= PNG_ADD_ALPHA;
 }

@@ -478,7 +478,7 @@ png_do_packswap(png_row_infop row_info, png_bytep row)
         *rp = table[*rp];
   }
 }
-#endif /* PACKSWAP || WRITE_PACKSWAP */
+#endif /* PNG_READ_PACKSWAP_SUPPORTED or PNG_WRITE_PACKSWAP_SUPPORTED */

 #if defined(PNG_WRITE_FILLER_SUPPORTED) || \
    defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
@@ -605,7 +605,7 @@ png_do_bgr(png_row_infop row_info, png_bytep row)
 {
   png_debug(1, "in png_do_bgr");

-   if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
+   if ((row_info->color_type & PNG_COLOR_MASK_COLOR))
   {
      png_uint_32 row_width = row_info->width;
      if (row_info->bit_depth == 8)
@@ -675,7 +675,7 @@ png_do_bgr(png_row_infop row_info, png_bytep row)
 #endif
   }
 }
-#endif /* READ_BGR || WRITE_BGR */
+#endif /* PNG_READ_BGR_SUPPORTED or PNG_WRITE_BGR_SUPPORTED */

 #if defined(PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED) || \
    defined(PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED)
@@ -778,7 +778,7 @@ png_do_check_palette_indexes(png_structrp png_ptr, png_row_infop row_info)
      }
   }
 }
-#endif /* CHECK_FOR_INVALID_INDEX */
+#endif /* PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED */

 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
@@ -828,7 +828,7 @@ png_get_user_transform_ptr(png_const_structrp png_ptr)
 png_uint_32 PNGAPI
 png_get_current_row_number(png_const_structrp png_ptr)
 {
-   /* See the comments in png.h - this is the sub-image row when reading an
+   /* See the comments in png.h - this is the sub-image row when reading and
    * interlaced image.
    */
   if (png_ptr != NULL)
@@ -844,6 +844,7 @@ png_get_current_pass_number(png_const_structrp png_ptr)
      return png_ptr->pass;
   return 8; /* invalid */
 }
-#endif /* USER_TRANSFORM_INFO */
-#endif /* READ_USER_TRANSFORM || WRITE_USER_TRANSFORM */
-#endif /* READ || WRITE */
+#endif /* PNG_USER_TRANSFORM_INFO_SUPPORTED */
+#endif /* PNG_READ_USER_TRANSFORM_SUPPORTED ||
+          PNG_WRITE_USER_TRANSFORM_SUPPORTED */
+#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
--- a/pngusr.dfa
+++ b/pngusr.dfa
@@ -4,12 +4,11 @@
 #
 # Enter build configuration options in this file
 #
-# Security settings: these limits have default values that are set in
-# scripts/pnglibconf.dfa; you can change them here by entering the
-# appropriate values as #defines preceded by '@' (to cause them
-# to be passed through to the build of pnglibconf.h), for example:
+# Security settings: by default these limits are unset, you can change them
+# here by entering the appropriate values as #defines preceded by '@' (to cause,
+# them to be passed through to the build of pnglibconf.h), for example:
 #
-# @# define PNG_USER_WIDTH_MAX 65535
-# @# define PNG_USER_HEIGHT_MAX 65535
-# @# define PNG_USER_CHUNK_CACHE_MAX 256
-# @# define PNG_USER_CHUNK_MALLOC_MAX 640000
+# @# define PNG_USER_WIDTH_MAX 1000000
+# @# define PNG_USER_HEIGHT_MAX 1000000
+# @# define PNG_USER_CHUNK_CACHE_MAX 128
+# @# define PNG_USER_CHUNK_MALLOC_MAX 8000000
--- a/pngwio.c
+++ b/pngwio.c
@@ -1,7 +1,7 @@

 /* pngwio.c - functions for data output
 *
- * Last changed in libpng 1.6.15 [November 20, 2014]
+ * Last changed in libpng 1.6.9 [February 6, 2014]
 * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -151,7 +151,7 @@ png_set_write_fn(png_structrp png_ptr, png_voidp io_ptr,
 #  endif
 #else
   PNG_UNUSED(output_flush_fn)
-#endif /* WRITE_FLUSH */
+#endif /* PNG_WRITE_FLUSH_SUPPORTED */

 #ifdef PNG_READ_SUPPORTED
   /* It is an error to read while writing a png file */
@@ -165,4 +165,4 @@ png_set_write_fn(png_structrp png_ptr, png_voidp io_ptr,
   }
 #endif
 }
-#endif /* WRITE */
+#endif /* PNG_WRITE_SUPPORTED */
--- a/pngwrite.c
+++ b/pngwrite.c
@@ -1,8 +1,8 @@

 /* pngwrite.c - general routines to write a PNG file
 *
- * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.11 [June 5, 2014]
+ * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
@@ -24,7 +24,7 @@ static void
 write_unknown_chunks(png_structrp png_ptr, png_const_inforp info_ptr,
   unsigned int where)
 {
-   if (info_ptr->unknown_chunks_num != 0)
+   if (info_ptr->unknown_chunks_num)
   {
      png_const_unknown_chunkp up;

@@ -33,7 +33,7 @@ write_unknown_chunks(png_structrp png_ptr, png_const_inforp info_ptr,
      for (up = info_ptr->unknown_chunks;
           up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;
           ++up)
-         if ((up->location & where) != 0)
+         if (up->location & where)
      {
         /* If per-chunk unknown chunk handling is enabled use it, otherwise
          * just write the chunks the application has set.
@@ -69,7 +69,7 @@ write_unknown_chunks(png_structrp png_ptr, png_const_inforp info_ptr,
      }
   }
 }
-#endif /* WRITE_UNKNOWN_CHUNKS */
+#endif /* PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED */

 /* Writes all the PNG information.  This is the suggested way to use the
 * library.  If you have a new chunk to add, make a function to write it,
@@ -88,14 +88,14 @@ png_write_info_before_PLTE(png_structrp png_ptr, png_const_inforp info_ptr)
   if (png_ptr == NULL || info_ptr == NULL)
      return;

-   if ((png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE) == 0)
+   if (!(png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE))
   {
   /* Write PNG signature */
   png_write_sig(png_ptr);

 #ifdef PNG_MNG_FEATURES_SUPPORTED
-   if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) != 0 && \
-       png_ptr->mng_features_permitted != 0)
+   if ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) && \
+       (png_ptr->mng_features_permitted))
   {
      png_warning(png_ptr, "MNG features are not allowed in a PNG datastream");
      png_ptr->mng_features_permitted = 0;
@@ -129,9 +129,9 @@ png_write_info_before_PLTE(png_structrp png_ptr, png_const_inforp info_ptr)
    */
 #ifdef PNG_GAMMA_SUPPORTED
 #  ifdef PNG_WRITE_gAMA_SUPPORTED
-      if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
-          (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_gAMA) != 0 &&
-          (info_ptr->valid & PNG_INFO_gAMA) != 0)
+      if (!(info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) &&
+         (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_gAMA) &&
+         (info_ptr->valid & PNG_INFO_gAMA))
         png_write_gAMA_fixed(png_ptr, info_ptr->colorspace.gamma);
 #  endif
 #endif
@@ -141,11 +141,11 @@ png_write_info_before_PLTE(png_structrp png_ptr, png_const_inforp info_ptr)
    * and it matches one of the known sRGB ones issue a warning.
    */
 #  ifdef PNG_WRITE_iCCP_SUPPORTED
-      if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
-          (info_ptr->valid & PNG_INFO_iCCP) != 0)
+      if (!(info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) &&
+         (info_ptr->valid & PNG_INFO_iCCP))
      {
 #        ifdef PNG_WRITE_sRGB_SUPPORTED
-            if ((info_ptr->valid & PNG_INFO_sRGB) != 0)
+            if (info_ptr->valid & PNG_INFO_sRGB)
               png_app_warning(png_ptr,
                  "profile matches sRGB but writing iCCP instead");
 #        endif
@@ -159,22 +159,22 @@ png_write_info_before_PLTE(png_structrp png_ptr, png_const_inforp info_ptr)
 #  endif

 #  ifdef PNG_WRITE_sRGB_SUPPORTED
-      if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
-          (info_ptr->valid & PNG_INFO_sRGB) != 0)
+      if (!(info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) &&
+         (info_ptr->valid & PNG_INFO_sRGB))
         png_write_sRGB(png_ptr, info_ptr->colorspace.rendering_intent);
 #  endif /* WRITE_sRGB */
 #endif /* COLORSPACE */

 #ifdef PNG_WRITE_sBIT_SUPPORTED
-   if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
+   if (info_ptr->valid & PNG_INFO_sBIT)
      png_write_sBIT(png_ptr, &(info_ptr->sig_bit), info_ptr->color_type);
 #endif

 #ifdef PNG_COLORSPACE_SUPPORTED
 #  ifdef PNG_WRITE_cHRM_SUPPORTED
-      if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
-         (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) != 0 &&
-         (info_ptr->valid & PNG_INFO_cHRM) != 0)
+      if (!(info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) &&
+         (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) &&
+         (info_ptr->valid & PNG_INFO_cHRM))
         png_write_cHRM_fixed(png_ptr, &info_ptr->colorspace.end_points_xy);
 #  endif
 #endif
@@ -201,28 +201,23 @@ png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)

   png_write_info_before_PLTE(png_ptr, info_ptr);

-   if ((info_ptr->valid & PNG_INFO_PLTE) != 0)
+   if (info_ptr->valid & PNG_INFO_PLTE)
      png_write_PLTE(png_ptr, info_ptr->palette,
          (png_uint_32)info_ptr->num_palette);

-   else if ((info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) !=0)
+   else if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
      png_error(png_ptr, "Valid palette required for paletted images");

 #ifdef PNG_WRITE_tRNS_SUPPORTED
-   if ((info_ptr->valid & PNG_INFO_tRNS) !=0)
+   if (info_ptr->valid & PNG_INFO_tRNS)
   {
 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
      /* Invert the alpha channel (in tRNS) */
-      if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0 &&
+      if ((png_ptr->transformations & PNG_INVERT_ALPHA) &&
          info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
      {
-         int j, jend;
-
-         jend = info_ptr->num_trans;
-         if (jend > PNG_MAX_PALETTE_LENGTH)
-            jend = PNG_MAX_PALETTE_LENGTH;
-
-         for (j = 0; j<jend; ++j)
+         int j;
+         for (j = 0; j<(int)info_ptr->num_trans; j++)
            info_ptr->trans_alpha[j] =
               (png_byte)(255 - info_ptr->trans_alpha[j]);
      }
@@ -232,42 +227,42 @@ png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)
   }
 #endif
 #ifdef PNG_WRITE_bKGD_SUPPORTED
-   if ((info_ptr->valid & PNG_INFO_bKGD) != 0)
+   if (info_ptr->valid & PNG_INFO_bKGD)
      png_write_bKGD(png_ptr, &(info_ptr->background), info_ptr->color_type);
 #endif

 #ifdef PNG_WRITE_hIST_SUPPORTED
-   if ((info_ptr->valid & PNG_INFO_hIST) != 0)
+   if (info_ptr->valid & PNG_INFO_hIST)
      png_write_hIST(png_ptr, info_ptr->hist, info_ptr->num_palette);
 #endif

 #ifdef PNG_WRITE_oFFs_SUPPORTED
-   if ((info_ptr->valid & PNG_INFO_oFFs) != 0)
+   if (info_ptr->valid & PNG_INFO_oFFs)
      png_write_oFFs(png_ptr, info_ptr->x_offset, info_ptr->y_offset,
          info_ptr->offset_unit_type);
 #endif

 #ifdef PNG_WRITE_pCAL_SUPPORTED
-   if ((info_ptr->valid & PNG_INFO_pCAL) != 0)
+   if (info_ptr->valid & PNG_INFO_pCAL)
      png_write_pCAL(png_ptr, info_ptr->pcal_purpose, info_ptr->pcal_X0,
          info_ptr->pcal_X1, info_ptr->pcal_type, info_ptr->pcal_nparams,
          info_ptr->pcal_units, info_ptr->pcal_params);
 #endif

 #ifdef PNG_WRITE_sCAL_SUPPORTED
-   if ((info_ptr->valid & PNG_INFO_sCAL) != 0)
+   if (info_ptr->valid & PNG_INFO_sCAL)
      png_write_sCAL_s(png_ptr, (int)info_ptr->scal_unit,
          info_ptr->scal_s_width, info_ptr->scal_s_height);
 #endif /* sCAL */

 #ifdef PNG_WRITE_pHYs_SUPPORTED
-   if ((info_ptr->valid & PNG_INFO_pHYs) != 0)
+   if (info_ptr->valid & PNG_INFO_pHYs)
      png_write_pHYs(png_ptr, info_ptr->x_pixels_per_unit,
          info_ptr->y_pixels_per_unit, info_ptr->phys_unit_type);
 #endif /* pHYs */

 #ifdef PNG_WRITE_tIME_SUPPORTED
-   if ((info_ptr->valid & PNG_INFO_tIME) != 0)
+   if (info_ptr->valid & PNG_INFO_tIME)
   {
      png_write_tIME(png_ptr, &(info_ptr->mod_time));
      png_ptr->mode |= PNG_WROTE_tIME;
@@ -275,7 +270,7 @@ png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)
 #endif /* tIME */

 #ifdef PNG_WRITE_sPLT_SUPPORTED
-   if ((info_ptr->valid & PNG_INFO_sPLT) != 0)
+   if (info_ptr->valid & PNG_INFO_sPLT)
      for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
         png_write_sPLT(png_ptr, info_ptr->splt_palettes + i);
 #endif /* sPLT */
@@ -297,14 +292,11 @@ png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)
             info_ptr->text[i].lang,
             info_ptr->text[i].lang_key,
             info_ptr->text[i].text);
-         /* Mark this chunk as written */
-         if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
-            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
-         else
-            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
 #else
-         png_warning(png_ptr, "Unable to write international text");
+          png_warning(png_ptr, "Unable to write international text");
 #endif
+          /* Mark this chunk as written */
+          info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
      }

      /* If we want a compressed text chunk */
@@ -313,12 +305,13 @@ png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)
 #ifdef PNG_WRITE_zTXt_SUPPORTED
         /* Write compressed chunk */
         png_write_zTXt(png_ptr, info_ptr->text[i].key,
-             info_ptr->text[i].text, info_ptr->text[i].compression);
-         /* Mark this chunk as written */
-         info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
+             info_ptr->text[i].text, 0,
+             info_ptr->text[i].compression);
 #else
         png_warning(png_ptr, "Unable to write compressed text");
 #endif
+         /* Mark this chunk as written */
+         info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
      }

      else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
@@ -356,7 +349,7 @@ png_write_end(png_structrp png_ptr, png_inforp info_ptr)
   if (png_ptr == NULL)
      return;

-   if ((png_ptr->mode & PNG_HAVE_IDAT) == 0)
+   if (!(png_ptr->mode & PNG_HAVE_IDAT))
      png_error(png_ptr, "No IDATs written into file");

 #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
@@ -372,8 +365,8 @@ png_write_end(png_structrp png_ptr, png_inforp info_ptr)
 #endif
 #ifdef PNG_WRITE_tIME_SUPPORTED
      /* Check to see if user has supplied a time chunk */
-      if ((info_ptr->valid & PNG_INFO_tIME) != 0 &&
-          (png_ptr->mode & PNG_WROTE_tIME) == 0)
+      if ((info_ptr->valid & PNG_INFO_tIME) &&
+          !(png_ptr->mode & PNG_WROTE_tIME))
         png_write_tIME(png_ptr, &(info_ptr->mod_time));

 #endif
@@ -394,14 +387,11 @@ png_write_end(png_structrp png_ptr, png_inforp info_ptr)
                info_ptr->text[i].lang,
                info_ptr->text[i].lang_key,
                info_ptr->text[i].text);
-            /* Mark this chunk as written */
-            if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
-               info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
-            else
-               info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
 #else
            png_warning(png_ptr, "Unable to write international text");
 #endif
+            /* Mark this chunk as written */
+            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
         }

         else if (info_ptr->text[i].compression >= PNG_TEXT_COMPRESSION_zTXt)
@@ -409,12 +399,13 @@ png_write_end(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_WRITE_zTXt_SUPPORTED
            /* Write compressed chunk */
            png_write_zTXt(png_ptr, info_ptr->text[i].key,
-                info_ptr->text[i].text, info_ptr->text[i].compression);
-            /* Mark this chunk as written */
-            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
+                info_ptr->text[i].text, 0,
+                info_ptr->text[i].compression);
 #else
            png_warning(png_ptr, "Unable to write compressed text");
 #endif
+            /* Mark this chunk as written */
+            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
         }

         else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
@@ -423,11 +414,12 @@ png_write_end(png_structrp png_ptr, png_inforp info_ptr)
            /* Write uncompressed chunk */
            png_write_tEXt(png_ptr, info_ptr->text[i].key,
                info_ptr->text[i].text, 0);
-            /* Mark this chunk as written */
-            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
 #else
            png_warning(png_ptr, "Unable to write uncompressed text");
 #endif
+
+            /* Mark this chunk as written */
+            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
         }
      }
 #endif
@@ -440,6 +432,7 @@ png_write_end(png_structrp png_ptr, png_inforp info_ptr)

   /* Write end of PNG file */
   png_write_IEND(png_ptr);
+
   /* This flush, added in libpng-1.0.8, removed from libpng-1.0.9beta03,
    * and restored again in libpng-1.2.30, may cause some applications that
    * do not set png_ptr->output_flush_fn to crash.  If your application
@@ -487,7 +480,7 @@ png_create_write_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
 {
 #ifndef PNG_USER_MEM_SUPPORTED
   png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
-      error_fn, warn_fn, NULL, NULL, NULL);
+       error_fn, warn_fn, NULL, NULL, NULL);
 #else
   return png_create_write_struct_2(user_png_ver, error_ptr, error_fn,
       warn_fn, NULL, NULL, NULL);
@@ -500,9 +493,8 @@ png_create_write_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
    png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
 {
   png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
-      error_fn, warn_fn, mem_ptr, malloc_fn, free_fn);
-#endif /* USER_MEM */
-
+       error_fn, warn_fn, mem_ptr, malloc_fn, free_fn);
+#endif /* PNG_USER_MEM_SUPPORTED */
   if (png_ptr != NULL)
   {
      /* Set the zlib control values to defaults; they can be overridden by the
@@ -526,7 +518,7 @@ png_create_write_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
      png_ptr->zlib_text_mem_level = 8;
      png_ptr->zlib_text_window_bits = 15;
      png_ptr->zlib_text_method = 8;
-#endif /* WRITE_COMPRESSED_TEXT */
+#endif /* PNG_WRITE_COMPRESSED_TEXT_SUPPORTED */

      /* This is a highly dubious configuration option; by default it is off,
       * but it may be appropriate for private builds that are testing
@@ -534,17 +526,17 @@ png_create_write_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
       * applications that must not fail to write at all costs!
       */
 #ifdef PNG_BENIGN_WRITE_ERRORS_SUPPORTED
-      png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN;
      /* In stable builds only warn if an application error can be completely
       * handled.
       */
+      png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN;
 #endif

      /* App warnings are warnings in release (or release candidate) builds but
       * are errors during development.
       */
 #if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
-         png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN;
+      png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN;
 #endif

      /* TODO: delay this, it can be done in png_init_io() (if the app doesn't
@@ -623,7 +615,7 @@ png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
 {
   png_debug(1, "in png_do_write_intrapixel");

-   if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
+   if ((row_info->color_type & PNG_COLOR_MASK_COLOR))
   {
      int bytes_per_pixel;
      png_uint_32 row_width = row_info->width;
@@ -676,10 +668,10 @@ png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
            *(rp + 5) = (png_byte)(blue & 0xff);
         }
      }
-#endif /* WRITE_16BIT */
+#endif /* PNG_WRITE_16BIT_SUPPORTED */
   }
 }
-#endif /* MNG_FEATURES */
+#endif /* PNG_MNG_FEATURES_SUPPORTED */

 /* Called by user to write a row of image data */
 void PNGAPI
@@ -698,44 +690,44 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)
   if (png_ptr->row_number == 0 && png_ptr->pass == 0)
   {
      /* Make sure we wrote the header info */
-      if ((png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE) == 0)
+      if (!(png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE))
         png_error(png_ptr,
             "png_write_info was never called before png_write_row");

      /* Check for transforms that have been set but were defined out */
 #if !defined(PNG_WRITE_INVERT_SUPPORTED) && defined(PNG_READ_INVERT_SUPPORTED)
-      if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
+      if (png_ptr->transformations & PNG_INVERT_MONO)
         png_warning(png_ptr, "PNG_WRITE_INVERT_SUPPORTED is not defined");
 #endif

 #if !defined(PNG_WRITE_FILLER_SUPPORTED) && defined(PNG_READ_FILLER_SUPPORTED)
-      if ((png_ptr->transformations & PNG_FILLER) != 0)
+      if (png_ptr->transformations & PNG_FILLER)
         png_warning(png_ptr, "PNG_WRITE_FILLER_SUPPORTED is not defined");
 #endif
 #if !defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
    defined(PNG_READ_PACKSWAP_SUPPORTED)
-      if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
+      if (png_ptr->transformations & PNG_PACKSWAP)
         png_warning(png_ptr,
             "PNG_WRITE_PACKSWAP_SUPPORTED is not defined");
 #endif

 #if !defined(PNG_WRITE_PACK_SUPPORTED) && defined(PNG_READ_PACK_SUPPORTED)
-      if ((png_ptr->transformations & PNG_PACK) != 0)
+      if (png_ptr->transformations & PNG_PACK)
         png_warning(png_ptr, "PNG_WRITE_PACK_SUPPORTED is not defined");
 #endif

 #if !defined(PNG_WRITE_SHIFT_SUPPORTED) && defined(PNG_READ_SHIFT_SUPPORTED)
-      if ((png_ptr->transformations & PNG_SHIFT) != 0)
+      if (png_ptr->transformations & PNG_SHIFT)
         png_warning(png_ptr, "PNG_WRITE_SHIFT_SUPPORTED is not defined");
 #endif

 #if !defined(PNG_WRITE_BGR_SUPPORTED) && defined(PNG_READ_BGR_SUPPORTED)
-      if ((png_ptr->transformations & PNG_BGR) != 0)
+      if (png_ptr->transformations & PNG_BGR)
         png_warning(png_ptr, "PNG_WRITE_BGR_SUPPORTED is not defined");
 #endif

 #if !defined(PNG_WRITE_SWAP_SUPPORTED) && defined(PNG_READ_SWAP_SUPPORTED)
-      if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
+      if (png_ptr->transformations & PNG_SWAP_BYTES)
         png_warning(png_ptr, "PNG_WRITE_SWAP_SUPPORTED is not defined");
 #endif

@@ -744,13 +736,12 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)

 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
   /* If interlaced and not interested in row, return */
-   if (png_ptr->interlaced != 0 &&
-       (png_ptr->transformations & PNG_INTERLACE) != 0)
+   if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
   {
      switch (png_ptr->pass)
      {
         case 0:
-            if ((png_ptr->row_number & 0x07) != 0)
+            if (png_ptr->row_number & 0x07)
            {
               png_write_finish_row(png_ptr);
               return;
@@ -758,7 +749,7 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)
            break;

         case 1:
-            if ((png_ptr->row_number & 0x07) != 0 || png_ptr->width < 5)
+            if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
            {
               png_write_finish_row(png_ptr);
               return;
@@ -774,7 +765,7 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)
            break;

         case 3:
-            if ((png_ptr->row_number & 0x03) != 0 || png_ptr->width < 3)
+            if ((png_ptr->row_number & 0x03) || png_ptr->width < 3)
            {
               png_write_finish_row(png_ptr);
               return;
@@ -790,7 +781,7 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)
            break;

         case 5:
-            if ((png_ptr->row_number & 0x01) != 0 || png_ptr->width < 2)
+            if ((png_ptr->row_number & 0x01) || png_ptr->width < 2)
            {
               png_write_finish_row(png_ptr);
               return;
@@ -798,7 +789,7 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)
            break;

         case 6:
-            if ((png_ptr->row_number & 0x01) == 0)
+            if (!(png_ptr->row_number & 0x01))
            {
               png_write_finish_row(png_ptr);
               return;
@@ -832,7 +823,7 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)
 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
   /* Handle interlacing */
   if (png_ptr->interlaced && png_ptr->pass < 6 &&
-       (png_ptr->transformations & PNG_INTERLACE) != 0)
+       (png_ptr->transformations & PNG_INTERLACE))
   {
      png_do_write_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass);
      /* This should always get caught above, but still ... */
@@ -846,7 +837,7 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)

 #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
   /* Handle other transformations */
-   if (png_ptr->transformations != 0)
+   if (png_ptr->transformations)
      png_do_write_transformations(png_ptr, &row_info);
 #endif

@@ -867,7 +858,7 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)
    * 4. The filter_method is 64 and
    * 5. The color_type is RGB or RGBA
    */
-   if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
+   if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
       (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
   {
      /* Intrapixel differencing */
@@ -920,7 +911,7 @@ png_write_flush(png_structrp png_ptr)
   png_ptr->flush_rows = 0;
   png_flush(png_ptr);
 }
-#endif /* WRITE_FLUSH */
+#endif /* PNG_WRITE_FLUSH_SUPPORTED */

 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
 static void png_reset_filter_heuristics(png_structrp png_ptr);/* forward decl */
@@ -933,20 +924,18 @@ png_write_destroy(png_structrp png_ptr)
   png_debug(1, "in png_write_destroy");

   /* Free any memory zlib uses */
-   if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
+   if (png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED)
      deflateEnd(&png_ptr->zstream);

   /* Free our memory.  png_free checks NULL for us. */
   png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list);
   png_free(png_ptr, png_ptr->row_buf);
-   png_ptr->row_buf = NULL;
 #ifdef PNG_WRITE_FILTER_SUPPORTED
   png_free(png_ptr, png_ptr->prev_row);
-   png_free(png_ptr, png_ptr->try_row);
-   png_free(png_ptr, png_ptr->tst_row);
-   png_ptr->prev_row = NULL;
-   png_ptr->try_row = NULL;
-   png_ptr->tst_row = NULL;
+   png_free(png_ptr, png_ptr->sub_row);
+   png_free(png_ptr, png_ptr->up_row);
+   png_free(png_ptr, png_ptr->avg_row);
+   png_free(png_ptr, png_ptr->paeth_row);
 #endif

 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
@@ -954,13 +943,10 @@ png_write_destroy(png_structrp png_ptr)
   png_reset_filter_heuristics(png_ptr);
   png_free(png_ptr, png_ptr->filter_costs);
   png_free(png_ptr, png_ptr->inv_filter_costs);
-   png_ptr->filter_costs = NULL;
-   png_ptr->inv_filter_costs = NULL;
 #endif

 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
   png_free(png_ptr, png_ptr->chunk_list);
-   png_ptr->chunk_list = NULL;
 #endif

   /* The error handling and memory handling information is left intact at this
@@ -1006,102 +992,122 @@ png_set_filter(png_structrp png_ptr, int method, int filters)
      return;

 #ifdef PNG_MNG_FEATURES_SUPPORTED
-   if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
+   if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
       (method == PNG_INTRAPIXEL_DIFFERENCING))
      method = PNG_FILTER_TYPE_BASE;
+
 #endif
-
-   /* The only supported method, except for the check above, is
-    * PNG_FILTER_TYPE_BASE.  The code below does not use 'method' other than
-    * for the check, so just keep going if png_app_error returns.
-    */
-   if (method != PNG_FILTER_TYPE_BASE)
-      png_app_error(png_ptr, "Unknown custom filter method");
-
-   /* If filter writing is not supported the 'filters' value must be zero,
-    * otherwise the value must be a single, valid, filter value or a set of the
-    * mask values.  The defines in png.h are such that the filter masks used in
-    * this API and internally are 1<<(3+value), value is in the range 0..4, so
-    * this fits in a byte.
-    */
-#  ifdef PNG_WRITE_FILTER_SUPPORTED
-      /* Notice that PNG_NO_FILTERS is 0 and passes this test; this is OK
-       * because filters then gets set to PNG_FILTER_NONE, as is required.
-       */
-      if (filters < PNG_FILTER_VALUE_LAST)
-         filters = 0x08 << filters;
-
-      else if ((filters & ~PNG_ALL_FILTERS) != 0)
+   if (method == PNG_FILTER_TYPE_BASE)
+   {
+      switch (filters & (PNG_ALL_FILTERS | 0x07))
      {
-         png_app_error(png_ptr, "png_set_filter: invalid filters mask/value");
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+         case 5:
+         case 6:
+         case 7: png_app_error(png_ptr, "Unknown row filter for method 0");
+            /* FALL THROUGH */
+#endif /* PNG_WRITE_FILTER_SUPPORTED */
+         case PNG_FILTER_VALUE_NONE:
+            png_ptr->do_filter = PNG_FILTER_NONE; break;

-         /* For compatibility with the previous behavior assume a mask value was
-          * passed and ignore the non-mask bits.
-          */
-         filters &= PNG_ALL_FILTERS;
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+         case PNG_FILTER_VALUE_SUB:
+            png_ptr->do_filter = PNG_FILTER_SUB; break;

-         /* For a possibly foolish consistency (it shouldn't matter) set
-          * PNG_FILTER_NONE rather than 0.
-          */
-         if (filters == 0)
-            filters = PNG_FILTER_NONE;
+         case PNG_FILTER_VALUE_UP:
+            png_ptr->do_filter = PNG_FILTER_UP; break;
+
+         case PNG_FILTER_VALUE_AVG:
+            png_ptr->do_filter = PNG_FILTER_AVG; break;
+
+         case PNG_FILTER_VALUE_PAETH:
+            png_ptr->do_filter = PNG_FILTER_PAETH; break;
+
+         default:
+            png_ptr->do_filter = (png_byte)filters; break;
+#else
+         default:
+            png_app_error(png_ptr, "Unknown row filter for method 0");
+#endif /* PNG_WRITE_FILTER_SUPPORTED */
      }
-#  else
-      /* PNG_FILTER_VALUE_NONE and PNG_NO_FILTERS are both 0. */
-      if (filters != 0 && filters != PNG_FILTER_NONE)
-         png_app_error(png_ptr, "png_set_filter: no filters supported");

-      filters = PNG_FILTER_NONE;
-#  endif
-
-#  ifdef PNG_WRITE_FILTER_SUPPORTED
      /* If we have allocated the row_buf, this means we have already started
       * with the image and we should have allocated all of the filter buffers
       * that have been selected.  If prev_row isn't already allocated, then
       * it is too late to start using the filters that need it, since we
       * will be missing the data in the previous row.  If an application
       * wants to start and stop using particular filters during compression,
-       * it should start out with all of the filters, and then remove them
-       * or add them back after the start of compression.
-       *
-       * NOTE: this is a nasty constraint on the code, because it means that the
-       * prev_row buffer must be maintained even if there are currently no
-       * 'prev_row' requiring filters active.
+       * it should start out with all of the filters, and then add and
+       * remove them after the start of compression.
       */
      if (png_ptr->row_buf != NULL)
      {
-         /* Repeat the checks in png_write_start_row; 1 pixel high or wide
-          * images cannot benefit from certain filters.  If this isn't done here
-          * the check below will fire on 1 pixel high images.
-          */
-         if (png_ptr->height == 1)
-            filters &= ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
-
-         if (png_ptr->width == 1)
-            filters &= ~(PNG_FILTER_SUB|PNG_FILTER_AVG|PNG_FILTER_PAETH);
-
-         if ((filters & (PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH)) != 0
-            && png_ptr->prev_row == NULL)
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+         if ((png_ptr->do_filter & PNG_FILTER_SUB) && png_ptr->sub_row == NULL)
         {
-            /* This is the error case, however it is benign - the previous row
-             * is not available so the filter can't be used.  Just warn here.
-             */
-            png_app_warning(png_ptr,
-               "png_set_filter: UP/AVG/PAETH cannot be added after start");
-            filters &= ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
+            png_ptr->sub_row = (png_bytep)png_malloc(png_ptr,
+                (png_ptr->rowbytes + 1));
+            png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;
         }

-         /* Allocate any required buffers that have not already been allocated.
-          */
-         png_write_alloc_filter_row_buffers(png_ptr, filters);
-      }
-#  endif /* WRITE_FILTER */
+         if ((png_ptr->do_filter & PNG_FILTER_UP) && png_ptr->up_row == NULL)
+         {
+            if (png_ptr->prev_row == NULL)
+            {
+               png_warning(png_ptr, "Can't add Up filter after starting");
+               png_ptr->do_filter = (png_byte)(png_ptr->do_filter &
+                   ~PNG_FILTER_UP);
+            }

-   /* Finally store the value.
-    * TODO: this field could probably be removed if neither READ nor
-    * WRITE_FILTER are supported.
-    */
-   png_ptr->do_filter = (png_byte)filters; /* SAFE: checked above */
+            else
+            {
+               png_ptr->up_row = (png_bytep)png_malloc(png_ptr,
+                   (png_ptr->rowbytes + 1));
+               png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;
+            }
+         }
+
+         if ((png_ptr->do_filter & PNG_FILTER_AVG) && png_ptr->avg_row == NULL)
+         {
+            if (png_ptr->prev_row == NULL)
+            {
+               png_warning(png_ptr, "Can't add Average filter after starting");
+               png_ptr->do_filter = (png_byte)(png_ptr->do_filter &
+                   ~PNG_FILTER_AVG);
+            }
+
+            else
+            {
+               png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,
+                   (png_ptr->rowbytes + 1));
+               png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;
+            }
+         }
+
+         if ((png_ptr->do_filter & PNG_FILTER_PAETH) &&
+             png_ptr->paeth_row == NULL)
+         {
+            if (png_ptr->prev_row == NULL)
+            {
+               png_warning(png_ptr, "Can't add Paeth filter after starting");
+               png_ptr->do_filter &= (png_byte)(~PNG_FILTER_PAETH);
+            }
+
+            else
+            {
+               png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,
+                   (png_ptr->rowbytes + 1));
+               png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
+            }
+         }
+
+         if (png_ptr->do_filter == PNG_NO_FILTERS)
+#endif /* PNG_WRITE_FILTER_SUPPORTED */
+            png_ptr->do_filter = PNG_FILTER_NONE;
+      }
+   }
+   else
+      png_error(png_ptr, "Unknown custom filter method");
 }

 /* This allows us to influence the way in which libpng chooses the "best"
@@ -1239,7 +1245,7 @@ png_set_filter_heuristics(png_structrp png_ptr, int heuristic_method,
   /* The internal API allocates all the arrays and ensures that the elements of
    * those arrays are set to the default value.
    */
-   if (png_init_filter_heuristics(png_ptr, heuristic_method, num_weights) == 0)
+   if (!png_init_filter_heuristics(png_ptr, heuristic_method, num_weights))
      return;

   /* If using the weighted method copy in the weights. */
@@ -1294,7 +1300,7 @@ png_set_filter_heuristics_fixed(png_structrp png_ptr, int heuristic_method,
   /* The internal API allocates all the arrays and ensures that the elements of
    * those arrays are set to the default value.
    */
-   if (png_init_filter_heuristics(png_ptr, heuristic_method, num_weights) == 0)
+   if (!png_init_filter_heuristics(png_ptr, heuristic_method, num_weights))
      return;

   /* If using the weighted method copy in the weights. */
@@ -1348,9 +1354,8 @@ png_set_filter_heuristics_fixed(png_structrp png_ptr, int heuristic_method,
   }
 }
 #endif /* FIXED_POINT */
-#endif /* WRITE_WEIGHTED_FILTER */
+#endif /* PNG_WRITE_WEIGHTED_FILTER_SUPPORTED */

-#ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
 void PNGAPI
 png_set_compression_level(png_structrp png_ptr, int level)
 {
@@ -1433,7 +1438,6 @@ png_set_compression_method(png_structrp png_ptr, int method)

   png_ptr->zlib_method = method;
 }
-#endif /* WRITE_CUSTOMIZE_COMPRESSION */

 /* The following were added to libpng-1.5.4 */
 #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
@@ -1507,7 +1511,7 @@ png_set_text_compression_method(png_structrp png_ptr, int method)

   png_ptr->zlib_text_method = method;
 }
-#endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
+#endif /* PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED */
 /* end of API added to libpng-1.5.4 */

 void PNGAPI
@@ -1555,7 +1559,7 @@ png_write_png(png_structrp png_ptr, png_inforp info_ptr,
   /* ------ these transformations don't touch the info structure ------- */

   /* Invert monochrome pixels */
-   if ((transforms & PNG_TRANSFORM_INVERT_MONO) != 0)
+   if (transforms & PNG_TRANSFORM_INVERT_MONO)
 #ifdef PNG_WRITE_INVERT_SUPPORTED
      png_set_invert_mono(png_ptr);
 #else
@@ -1565,16 +1569,16 @@ png_write_png(png_structrp png_ptr, png_inforp info_ptr,
   /* Shift the pixels up to a legal bit depth and fill in
    * as appropriate to correctly scale the image.
    */
-   if ((transforms & PNG_TRANSFORM_SHIFT) != 0)
+   if (transforms & PNG_TRANSFORM_SHIFT)
 #ifdef PNG_WRITE_SHIFT_SUPPORTED
-      if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
+      if (info_ptr->valid & PNG_INFO_sBIT)
         png_set_shift(png_ptr, &info_ptr->sig_bit);
 #else
      png_app_error(png_ptr, "PNG_TRANSFORM_SHIFT not supported");
 #endif

   /* Pack pixels into bytes */
-   if ((transforms & PNG_TRANSFORM_PACKING) != 0)
+   if (transforms & PNG_TRANSFORM_PACKING)
 #ifdef PNG_WRITE_PACK_SUPPORTED
      png_set_packing(png_ptr);
 #else
@@ -1582,7 +1586,7 @@ png_write_png(png_structrp png_ptr, png_inforp info_ptr,
 #endif

   /* Swap location of alpha bytes from ARGB to RGBA */
-   if ((transforms & PNG_TRANSFORM_SWAP_ALPHA) != 0)
+   if (transforms & PNG_TRANSFORM_SWAP_ALPHA)
 #ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
      png_set_swap_alpha(png_ptr);
 #else
@@ -1593,13 +1597,13 @@ png_write_png(png_structrp png_ptr, png_inforp info_ptr,
    * RGB, note that the code expects the input color type to be G or RGB; no
    * alpha channel.
    */
-   if ((transforms & (PNG_TRANSFORM_STRIP_FILLER_AFTER|
-      PNG_TRANSFORM_STRIP_FILLER_BEFORE)) != 0)
+   if (transforms &
+      (PNG_TRANSFORM_STRIP_FILLER_AFTER|PNG_TRANSFORM_STRIP_FILLER_BEFORE))
   {
 #ifdef PNG_WRITE_FILLER_SUPPORTED
-      if ((transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER) != 0)
+      if (transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER)
      {
-         if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
+         if (transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE)
            png_app_error(png_ptr,
               "PNG_TRANSFORM_STRIP_FILLER: BEFORE+AFTER not supported");

@@ -1607,7 +1611,7 @@ png_write_png(png_structrp png_ptr, png_inforp info_ptr,
         png_set_filler(png_ptr, 0, PNG_FILLER_AFTER);
      }

-      else if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
+      else if (transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE)
         png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
 #else
      png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_FILLER not supported");
@@ -1615,7 +1619,7 @@ png_write_png(png_structrp png_ptr, png_inforp info_ptr,
   }

   /* Flip BGR pixels to RGB */
-   if ((transforms & PNG_TRANSFORM_BGR) != 0)
+   if (transforms & PNG_TRANSFORM_BGR)
 #ifdef PNG_WRITE_BGR_SUPPORTED
      png_set_bgr(png_ptr);
 #else
@@ -1623,7 +1627,7 @@ png_write_png(png_structrp png_ptr, png_inforp info_ptr,
 #endif

   /* Swap bytes of 16-bit files to most significant byte first */
-   if ((transforms & PNG_TRANSFORM_SWAP_ENDIAN) != 0)
+   if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
 #ifdef PNG_WRITE_SWAP_SUPPORTED
      png_set_swap(png_ptr);
 #else
@@ -1631,7 +1635,7 @@ png_write_png(png_structrp png_ptr, png_inforp info_ptr,
 #endif

   /* Swap bits of 1, 2, 4 bit packed pixel formats */
-   if ((transforms & PNG_TRANSFORM_PACKSWAP) != 0)
+   if (transforms & PNG_TRANSFORM_PACKSWAP)
 #ifdef PNG_WRITE_PACKSWAP_SUPPORTED
      png_set_packswap(png_ptr);
 #else
@@ -1639,7 +1643,7 @@ png_write_png(png_structrp png_ptr, png_inforp info_ptr,
 #endif

   /* Invert the alpha channel from opacity to transparency */
-   if ((transforms & PNG_TRANSFORM_INVERT_ALPHA) != 0)
+   if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
      png_set_invert_alpha(png_ptr);
 #else
@@ -1734,10 +1738,10 @@ png_write_image_16bit(png_voidp argument)
   int aindex = 0;
   png_uint_32 y = image->height;

-   if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
+   if (image->format & PNG_FORMAT_FLAG_ALPHA)
   {
 #     ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
-         if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
+         if (image->format & PNG_FORMAT_FLAG_AFIRST)
         {
            aindex = -1;
            ++input_row; /* To point to the first component */
@@ -1889,13 +1893,13 @@ png_write_image_8bit(png_voidp argument)
   png_uint_32 y = image->height;
   const int channels = (image->format & PNG_FORMAT_FLAG_COLOR) ? 3 : 1;

-   if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
+   if (image->format & PNG_FORMAT_FLAG_ALPHA)
   {
      png_bytep row_end;
      int aindex;

 #     ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
-         if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
+         if (image->format & PNG_FORMAT_FLAG_AFIRST)
         {
            aindex = -1;
            ++input_row; /* To point to the first component */
@@ -2009,13 +2013,13 @@ png_image_set_PLTE(png_image_write_control *display)
      /* This gets automatically converted to sRGB with reversal of the
       * pre-multiplication if the color-map has an alpha channel.
       */
-      if ((format & PNG_FORMAT_FLAG_LINEAR) != 0)
+      if (format & PNG_FORMAT_FLAG_LINEAR)
      {
         png_const_uint_16p entry = png_voidcast(png_const_uint_16p, cmap);

         entry += i * channels;

-         if ((channels & 1) != 0) /* no alpha */
+         if (channels & 1) /* no alpha */
         {
            if (channels >= 3) /* RGB */
            {
@@ -2142,7 +2146,7 @@ png_image_write_main(png_voidp argument)
      display->row_stride = PNG_IMAGE_ROW_STRIDE(*image);

   /* Set the required transforms then write the rows in the correct order. */
-   if ((format & PNG_FORMAT_FLAG_COLORMAP) != 0)
+   if (format & PNG_FORMAT_FLAG_COLORMAP)
   {
      if (display->colormap != NULL && image->colormap_entries > 0)
      {
@@ -2179,7 +2183,7 @@ png_image_write_main(png_voidp argument)
      /* The gamma here is 1.0 (linear) and the cHRM chunk matches sRGB. */
      png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_LINEAR);

-      if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0)
+      if (!(image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB))
         png_set_cHRM_fixed(png_ptr, info_ptr,
            /* color      x       y */
            /* white */ 31270, 32900,
@@ -2189,7 +2193,7 @@ png_image_write_main(png_voidp argument)
         );
   }

-   else if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0)
+   else if (!(image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB))
      png_set_sRGB(png_ptr, info_ptr, PNG_sRGB_INTENT_PERCEPTUAL);

   /* Else writing an 8-bit file and the *colors* aren't sRGB, but the 8-bit
@@ -2210,12 +2214,12 @@ png_image_write_main(png_voidp argument)
   {
      PNG_CONST png_uint_16 le = 0x0001;

-      if ((*(png_const_bytep) & le) != 0)
+      if (*(png_const_bytep)&le)
         png_set_swap(png_ptr);
   }

 #  ifdef PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED
-      if ((format & PNG_FORMAT_FLAG_BGR) != 0)
+      if (format & PNG_FORMAT_FLAG_BGR)
      {
         if (!colormap && (format & PNG_FORMAT_FLAG_COLOR) != 0)
            png_set_bgr(png_ptr);
@@ -2224,7 +2228,7 @@ png_image_write_main(png_voidp argument)
 #  endif

 #  ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
-      if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
+      if (format & PNG_FORMAT_FLAG_AFIRST)
      {
         if (!colormap && (format & PNG_FORMAT_FLAG_ALPHA) != 0)
            png_set_swap_alpha(png_ptr);
@@ -2235,7 +2239,7 @@ png_image_write_main(png_voidp argument)
   /* If there are 16 or fewer color-map entries we wrote a lower bit depth
    * above, but the application data is still byte packed.
    */
-   if (colormap != 0 && image->colormap_entries <= 16)
+   if (colormap && image->colormap_entries <= 16)
      png_set_packing(png_ptr);

   /* That should have handled all (both) the transforms. */
@@ -2322,7 +2326,7 @@ png_image_write_to_stdio(png_imagep image, FILE *file, int convert_to_8bit,
   {
      if (file != NULL)
      {
-         if (png_image_write_init(image) != 0)
+         if (png_image_write_init(image))
         {
            png_image_write_control display;
            int result;
@@ -2377,7 +2381,7 @@ png_image_write_to_file(png_imagep image, const char *file_name,
         if (fp != NULL)
         {
            if (png_image_write_to_stdio(image, fp, convert_to_8bit, buffer,
-               row_stride, colormap) != 0)
+               row_stride, colormap))
            {
               int error; /* from fflush/fclose */

@@ -2428,6 +2432,6 @@ png_image_write_to_file(png_imagep image, const char *file_name,
   else
      return 0;
 }
-#endif /* STDIO */
+#endif /* PNG_STDIO_SUPPORTED */
 #endif /* SIMPLIFIED_WRITE */
-#endif /* WRITE */
+#endif /* PNG_WRITE_SUPPORTED */
--- a/pngwtran.c
+++ b/pngwtran.c
@@ -1,7 +1,7 @@

 /* pngwtran.c - transforms the data in a row for PNG writers
 *
- * Last changed in libpng 1.6.15 [November 20, 2014]
+ * Last changed in libpng 1.6.9 [February 6, 2014]
 * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -177,7 +177,7 @@ png_do_shift(png_row_infop row_info, png_bytep row,
      int shift_start[4], shift_dec[4];
      int channels = 0;

-      if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
+      if (row_info->color_type & PNG_COLOR_MASK_COLOR)
      {
         shift_start[channels] = row_info->bit_depth - bit_depth->red;
         shift_dec[channels] = bit_depth->red;
@@ -199,7 +199,7 @@ png_do_shift(png_row_infop row_info, png_bytep row,
         channels++;
      }

-      if ((row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0)
+      if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
      {
         shift_start[channels] = row_info->bit_depth - bit_depth->alpha;
         shift_dec[channels] = bit_depth->alpha;
@@ -353,7 +353,7 @@ png_do_write_swap_alpha(png_row_infop row_info, png_bytep row)
               *(dp++) = save[1];
            }
         }
-#endif /* WRITE_16BIT */
+#endif /* PNG_WRITE_16BIT_SUPPORTED */
      }

      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
@@ -392,7 +392,7 @@ png_do_write_swap_alpha(png_row_infop row_info, png_bytep row)
               *(dp++) = save[1];
            }
         }
-#endif /* WRITE_16BIT */
+#endif /* PNG_WRITE_16BIT_SUPPORTED */
      }
   }
 }
@@ -449,7 +449,7 @@ png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
               *(dp++) = (png_byte)(255 - *(sp++));
            }
         }
-#endif /* WRITE_16BIT */
+#endif /* PNG_WRITE_16BIT_SUPPORTED */
      }

      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
@@ -487,7 +487,7 @@ png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
               *(dp++) = (png_byte)(255 - *(sp++));
            }
         }
-#endif /* WRITE_16BIT */
+#endif /* PNG_WRITE_16BIT_SUPPORTED */
      }
   }
 }
@@ -505,7 +505,7 @@ png_do_write_transformations(png_structrp png_ptr, png_row_infop row_info)
      return;

 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
-   if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
+   if (png_ptr->transformations & PNG_USER_TRANSFORM)
      if (png_ptr->write_user_transform_fn != NULL)
         (*(png_ptr->write_user_transform_fn)) /* User write transform
                                                 function */
@@ -521,54 +521,52 @@ png_do_write_transformations(png_structrp png_ptr, png_row_infop row_info)
 #endif

 #ifdef PNG_WRITE_FILLER_SUPPORTED
-   if ((png_ptr->transformations & PNG_FILLER) != 0)
+   if (png_ptr->transformations & PNG_FILLER)
      png_do_strip_channel(row_info, png_ptr->row_buf + 1,
         !(png_ptr->flags & PNG_FLAG_FILLER_AFTER));
 #endif

 #ifdef PNG_WRITE_PACKSWAP_SUPPORTED
-   if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
+   if (png_ptr->transformations & PNG_PACKSWAP)
      png_do_packswap(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_WRITE_PACK_SUPPORTED
-   if ((png_ptr->transformations & PNG_PACK) != 0)
+   if (png_ptr->transformations & PNG_PACK)
      png_do_pack(row_info, png_ptr->row_buf + 1,
          (png_uint_32)png_ptr->bit_depth);
 #endif

 #ifdef PNG_WRITE_SWAP_SUPPORTED
-#  ifdef PNG_16BIT_SUPPORTED
-   if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
+   if (png_ptr->transformations & PNG_SWAP_BYTES)
      png_do_swap(row_info, png_ptr->row_buf + 1);
-#  endif
 #endif

 #ifdef PNG_WRITE_SHIFT_SUPPORTED
-   if ((png_ptr->transformations & PNG_SHIFT) != 0)
+   if (png_ptr->transformations & PNG_SHIFT)
      png_do_shift(row_info, png_ptr->row_buf + 1,
          &(png_ptr->shift));
 #endif

 #ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
-   if ((png_ptr->transformations & PNG_SWAP_ALPHA) != 0)
+   if (png_ptr->transformations & PNG_SWAP_ALPHA)
      png_do_write_swap_alpha(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
-   if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0)
+   if (png_ptr->transformations & PNG_INVERT_ALPHA)
      png_do_write_invert_alpha(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_WRITE_BGR_SUPPORTED
-   if ((png_ptr->transformations & PNG_BGR) != 0)
+   if (png_ptr->transformations & PNG_BGR)
      png_do_bgr(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_WRITE_INVERT_SUPPORTED
-   if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
+   if (png_ptr->transformations & PNG_INVERT_MONO)
      png_do_invert(row_info, png_ptr->row_buf + 1);
 #endif
 }
-#endif /* WRITE_TRANSFORMS */
-#endif /* WRITE */
+#endif /* PNG_WRITE_TRANSFORMS_SUPPORTED */
+#endif /* PNG_WRITE_SUPPORTED */
--- a/pngwutil.c
+++ b/pngwutil.c
--- a/projects/visualc71/libpng.vcproj
+++ b/projects/visualc71/libpng.vcproj
@@ -30,7 +30,7 @@
 				Name="VCCustomBuildTool"/>
 			<Tool
 				Name="VCLinkerTool"
-				OutputFile="$(OutDir)/libpng17.dll"
+				OutputFile="$(OutDir)/libpng16.dll"
 				LinkIncremental="1"/>
 			<Tool
 				Name="VCMIDLTool"/>
@@ -78,7 +78,7 @@
 				Name="VCCustomBuildTool"/>
 			<Tool
 				Name="VCLinkerTool"
-				OutputFile="$(OutDir)/libpng17d.dll"
+				OutputFile="$(OutDir)/libpng16d.dll"
 				GenerateDebugInformation="TRUE"/>
 			<Tool
 				Name="VCMIDLTool"/>
@@ -126,7 +126,7 @@
 				Name="VCCustomBuildTool"/>
 			<Tool
 				Name="VCLinkerTool"
-				OutputFile="$(OutDir)/libpng17vb.dll"
+				OutputFile="$(OutDir)/libpng16vb.dll"
 				LinkIncremental="1"/>
 			<Tool
 				Name="VCMIDLTool"/>
--- a/projects/visualc71/pngtest.vcproj
+++ b/projects/visualc71/pngtest.vcproj
@@ -130,7 +130,7 @@ $(TargetPath) ..\..\pngtest.png $(IntDir)\pngout.png"
 				Name="VCLinkerTool"
 				OutputFile="$(OutDir)/pngtest.exe"
 				LinkIncremental="1"
-				IgnoreDefaultLibraryNames="$(IntDir)\libpng17b.lib"
+				IgnoreDefaultLibraryNames="$(IntDir)\libpng16b.lib"
 				SubSystem="1"
 				TargetMachine="1"/>
 			<Tool
--- a/projects/vstudio/libpng/libpng.vcxproj
+++ b/projects/vstudio/libpng/libpng.vcxproj
@@ -63,23 +63,23 @@
    <LinkIncremental>false</LinkIncremental>
    <CustomBuildBeforeTargets>
    </CustomBuildBeforeTargets>
-    <TargetName>$(ProjectName)17</TargetName>
+    <TargetName>$(ProjectName)16</TargetName>
  </PropertyGroup>
  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
    <LinkIncremental>false</LinkIncremental>
    <CustomBuildBeforeTargets />
-    <TargetName>$(ProjectName)17</TargetName>
+    <TargetName>$(ProjectName)16</TargetName>
  </PropertyGroup>
  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
    <LinkIncremental>false</LinkIncremental>
    <CustomBuildBeforeTargets>
    </CustomBuildBeforeTargets>
-    <TargetName>$(ProjectName)17</TargetName>
+    <TargetName>$(ProjectName)16</TargetName>
  </PropertyGroup>
  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
    <LinkIncremental>false</LinkIncremental>
    <CustomBuildBeforeTargets />
-    <TargetName>$(ProjectName)17</TargetName>
+    <TargetName>$(ProjectName)16</TargetName>
  </PropertyGroup>
  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
    <ClCompile>
@@ -107,7 +107,7 @@
      <SubSystem>Windows</SubSystem>
      <GenerateDebugInformation>true</GenerateDebugInformation>
      <AdditionalDependencies>zlib.lib</AdditionalDependencies>
-      <Version>17</Version>
+      <Version>16</Version>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
    </Link>
  </ItemDefinitionGroup>
@@ -164,7 +164,7 @@
      <EnableCOMDATFolding>true</EnableCOMDATFolding>
      <OptimizeReferences>true</OptimizeReferences>
      <AdditionalDependencies>zlib.lib</AdditionalDependencies>
-      <Version>17</Version>
+      <Version>16</Version>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
    </Link>
  </ItemDefinitionGroup>
--- a/projects/vstudio/pngstest/pngstest.vcxproj
+++ b/projects/vstudio/pngstest/pngstest.vcxproj
@@ -96,7 +96,7 @@
    <Link>
      <SubSystem>Console</SubSystem>
      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng17.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib</AdditionalDependencies>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
    </Link>
    <CustomBuildStep>
@@ -129,7 +129,7 @@
    <Link>
      <SubSystem>Console</SubSystem>
      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng17.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib;zlib.lib</AdditionalDependencies>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
    </Link>
    <CustomBuildStep>
@@ -163,7 +163,7 @@
      <GenerateDebugInformation>true</GenerateDebugInformation>
      <EnableCOMDATFolding>true</EnableCOMDATFolding>
      <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng17.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib</AdditionalDependencies>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
      <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
    </Link>
@@ -199,7 +199,7 @@
      <GenerateDebugInformation>true</GenerateDebugInformation>
      <EnableCOMDATFolding>true</EnableCOMDATFolding>
      <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng17.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib;zlib.lib</AdditionalDependencies>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
      <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
    </Link>
--- a/projects/vstudio/pngtest/pngtest.vcxproj
+++ b/projects/vstudio/pngtest/pngtest.vcxproj
@@ -96,7 +96,7 @@
    <Link>
      <SubSystem>Console</SubSystem>
      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng17.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib</AdditionalDependencies>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
    </Link>
    <CustomBuildStep>
@@ -129,7 +129,7 @@
    <Link>
      <SubSystem>Console</SubSystem>
      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng17.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib;zlib.lib</AdditionalDependencies>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
    </Link>
    <CustomBuildStep>
@@ -164,7 +164,7 @@
      <EnableCOMDATFolding>true</EnableCOMDATFolding>
      <OptimizeReferences>true</OptimizeReferences>
      <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
-      <AdditionalDependencies>libpng17.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib</AdditionalDependencies>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
    </Link>
    <CustomBuildStep>
@@ -199,7 +199,7 @@
      <GenerateDebugInformation>true</GenerateDebugInformation>
      <EnableCOMDATFolding>true</EnableCOMDATFolding>
      <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng17.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib;zlib.lib</AdditionalDependencies>
      <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
    </Link>
--- a/projects/vstudio/pngunknown/pngunknown.vcxproj
+++ b/projects/vstudio/pngunknown/pngunknown.vcxproj
@@ -96,7 +96,7 @@
    <Link>
      <SubSystem>Console</SubSystem>
      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng17.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib</AdditionalDependencies>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
    </Link>
    <CustomBuildStep>
@@ -129,7 +129,7 @@
    <Link>
      <SubSystem>Console</SubSystem>
      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng17.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib;zlib.lib</AdditionalDependencies>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
    </Link>
    <CustomBuildStep>
@@ -163,7 +163,7 @@
      <GenerateDebugInformation>true</GenerateDebugInformation>
      <EnableCOMDATFolding>true</EnableCOMDATFolding>
      <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng17.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib</AdditionalDependencies>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
      <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
    </Link>
@@ -199,7 +199,7 @@
      <GenerateDebugInformation>true</GenerateDebugInformation>
      <EnableCOMDATFolding>true</EnableCOMDATFolding>
      <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng17.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib;zlib.lib</AdditionalDependencies>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
      <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
    </Link>
--- a/projects/vstudio/pngvalid/pngvalid.vcxproj
+++ b/projects/vstudio/pngvalid/pngvalid.vcxproj
@@ -96,7 +96,7 @@
    <Link>
      <SubSystem>Console</SubSystem>
      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng17.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib;zlib.lib</AdditionalDependencies>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
    </Link>
    <CustomBuildStep>
@@ -129,7 +129,7 @@
    <Link>
      <SubSystem>Console</SubSystem>
      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng17.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib;zlib.lib</AdditionalDependencies>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
    </Link>
    <CustomBuildStep>
@@ -163,7 +163,7 @@
      <GenerateDebugInformation>true</GenerateDebugInformation>
      <EnableCOMDATFolding>true</EnableCOMDATFolding>
      <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng17.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib;zlib.lib</AdditionalDependencies>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
      <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
    </Link>
@@ -199,7 +199,7 @@
      <GenerateDebugInformation>true</GenerateDebugInformation>
      <EnableCOMDATFolding>true</EnableCOMDATFolding>
      <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng17.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib;zlib.lib</AdditionalDependencies>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
      <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
    </Link>
--- a/projects/vstudio/readme.txt
+++ b/projects/vstudio/readme.txt
@@ -1,7 +1,7 @@

 VisualStudio instructions

-libpng version 1.7.0beta52 - February 21, 2015
+libpng version 1.6.13beta04 - August 8, 2014

 Copyright (c) 1998-2010 Glenn Randers-Pehrson

@@ -40,7 +40,7 @@ problems.

 If you don't use the Visual Studio defaults your application must still be built
 with the default runtime option (/MD).  If, for some reason, it is not then your
-application will crash inside libpng17.dll as soon as libpng tries to read
+application will crash inside libpng16.dll as soon as libpng tries to read
 from a file handle you pass in.

 If you do not want to use the DLL, for example for a very small application,
--- a/projects/vstudio/zlib.props
+++ b/projects/vstudio/zlib.props
@@ -2,7 +2,7 @@
 <!--
 * zlib.props - location of zlib source
 *
- * libpng version 1.7.0beta52 - February 21, 2015
+ * libpng version 1.6.13beta04 - August 8, 2014
 *
 * Copyright (c) 1998-2011 Glenn Randers-Pehrson
 *
--- a/scripts/README.txt
+++ b/scripts/README.txt
@@ -1,9 +1,9 @@

-Makefiles for  libpng version 1.7.0beta52 - February 21, 2015
+Makefiles for  libpng version 1.6.13beta04 - August 8, 2014

 pnglibconf.h.prebuilt       =>  Stores configuration settings
 makefile.linux    =>  Linux/ELF makefile
-                       (gcc, creates libpng17.so.17.1.7.0beta52)
+                       (gcc, creates libpng16.so.16.1.6.13beta04)
 makefile.gcc      =>  Generic makefile (gcc, creates static libpng.a)
 makefile.knr      =>  Archaic UNIX Makefile that converts files with
                       ansi2knr (Requires ansi2knr.c from
@@ -33,12 +33,12 @@ pnglibconf.h.prebuilt       =>  Stores configuration settings
 makefile.os2      =>  OS/2 Makefile (gcc and emx, requires libpng.def)
 makefile.sco      =>  For SCO OSr5  ELF and Unixware 7 with Native cc
 makefile.sggcc    =>  Silicon Graphics (gcc,
-                       creates libpng17.so.17.1.7.0beta52)
+                       creates libpng16.so.16.1.6.13beta04)
 makefile.sgi      =>  Silicon Graphics IRIX makefile (cc, creates static lib)
 makefile.solaris  =>  Solaris 2.X makefile (gcc,
-                       creates libpng17.so.17.1.7.0beta52)
+                       creates libpng16.so.16.1.6.13beta04)
 makefile.so9      =>  Solaris 9 makefile (gcc,
-                       creates libpng17.so.17.1.7.0beta52)
+                       creates libpng16.so.16.1.6.13beta04)
 makefile.std      =>  Generic UNIX makefile (cc, creates static libpng.a)
 makefile.sunos    =>  Sun makefile
 makefile.32sunu   =>  Sun Ultra 32-bit makefile
--- a/scripts/def.dfn
+++ b/scripts/def.dfn
@@ -1,7 +1,7 @@
-/* def.c - define format of libpng.def
+/* def.dfn - define format of libpng.def
 *
- * Last changed in libpng 1.6.16 [December 22, 2014]
- * Copyright (c) 2011-2014 Glenn Randers-Pehrson
+ * Last changed in libpng version 1.5.7 [December 15, 2011]
+ * Copyright (c) 2010-2011 Glenn Randers-Pehrson
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
@@ -21,7 +21,7 @@ PNG_DFN "OS2 DESCRIPTION "PNG image compression library""
 PNG_DFN "OS2 CODE PRELOAD MOVEABLE DISCARDABLE"
 PNG_DFN ""
 PNG_DFN "EXPORTS"
-PNG_DFN ";Version 1.7.0beta52"
+PNG_DFN ";Version 1.6.13beta04"

 #define PNG_EXPORTA(ordinal, type, name, args, attributes)\
        PNG_DFN "@" SYMBOL_PREFIX "@@" name "@"
--- a/scripts/descrip.mms
+++ b/scripts/descrip.mms
@@ -33,20 +33,20 @@ clean :


 # Other dependencies.
-png.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h, pnginfo.h, pngdebug.h
-pngpread.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h, pnginfo.h, pngdebug.h
-pngset.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h, pnginfo.h, pngdebug.h
-pngget.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h, pnginfo.h, pngdebug.h
-pngread.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h, pnginfo.h, pngdebug.h
-pngrtran.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h, pnginfo.h, pngdebug.h
-pngrutil.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h, pnginfo.h, pngdebug.h
-pngerror.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h, pnginfo.h, pngdebug.h
-pngmem.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h, pnginfo.h, pngdebug.h
-pngrio.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h, pnginfo.h, pngdebug.h
-pngwio.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h, pnginfo.h, pngdebug.h
-pngtrans.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h, pnginfo.h, pngdebug.h
-pngwrite.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h, pnginfo.h, pngdebug.h
-pngwtran.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h, pnginfo.h, pngdebug.h
-pngwutil.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h, pnginfo.h, pngdebug.h
+png.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngpread.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngset.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngget.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngread.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngrtran.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngrutil.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngerror.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngmem.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngrio.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngwio.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngtrans.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngwrite.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngwtran.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngwutil.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h

 pngtest.obj : png.h, pngconf.h, pnglibconf.h
--- a/scripts/dfn.awk
+++ b/scripts/dfn.awk
@@ -1,7 +1,7 @@
 #!/bin/awk -f
 # scripts/dfn.awk - process a .dfn file
 #
-# last changed in libpng version 1.5.19 - August 21, 2014
+# last changed in libpng version 1.5.19 - (PENDING RELEASE)
 #
 # Copyright (c) 2013-2014 Glenn Randers-Pehrson
 #
--- a/scripts/intprefix.dfn
+++ b/scripts/intprefix.dfn
@@ -1,8 +1,8 @@

-/* intprefix.c - generate an unprefixed internal symbol list
+/* intprefix.dfn - generate an unprefixed internal symbol list
 *
- * Last changed in libpng 1.6.16 [December 22, 2014]
- * Copyright (c) 2013-2014 Glenn Randers-Pehrson
+ * Last changed in libpng version 1.6.0 [January 30, 2012]
+ * Copyright (c) 2012 Glenn Randers-Pehrson
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
--- a/scripts/libpng-config-body.in
+++ b/scripts/libpng-config-body.in
--- a/scripts/libpng-config-head.in
+++ b/scripts/libpng-config-head.in
@@ -11,7 +11,7 @@

 # Modeled after libxml-config.

-version=1.7.0beta52
+version=1.6.13beta04
 prefix=""
 libdir=""
 libs=""
--- a/scripts/libpng.pc.in
+++ b/scripts/libpng.pc.in
@@ -1,10 +1,10 @@
 prefix=@prefix@
 exec_prefix=@exec_prefix@
 libdir=@libdir@
-includedir=@includedir@/libpng17
+includedir=@includedir@/libpng16

 Name: libpng
 Description: Loads and saves PNG files
-Version: 1.7.0beta52
-Libs: -L${libdir} -lpng17
+Version: 1.6.13beta04
+Libs: -L${libdir} -lpng16
 Cflags: -I${includedir}
--- a/scripts/makefile.32sunu
+++ b/scripts/makefile.32sunu
@@ -9,8 +9,8 @@
 # and license in png.h

 # Library name:
-LIBNAME=libpng17
-PNGMAJ = 17
+LIBNAME=libpng16
+PNGMAJ = 16

 # Shared library names:
 LIBSO=$(LIBNAME).so
@@ -29,7 +29,7 @@ RM_F=/bin/rm -f
 SUN_CC_FLAGS=-fast -xtarget=ultra
 SUN_LD_FLAGS=-fast -xtarget=ultra

-# where make install puts libpng.a, libpng17.so and libpng17/png.h
+# where make install puts libpng.a, libpng16.so and libpng16/png.h
 prefix=/a
 exec_prefix=$(prefix)

@@ -98,7 +98,7 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz\ -lm! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
@@ -107,9 +107,9 @@ libpng-config:
 	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
 	echo L_opts=\"-L$(LIBPATH)\"; \
 	echo R_opts=\"-R$(LIBPATH)\"; \
-	echo ccopts=\"-fast -xtarget=ultra\"; \
-	echo ldopts=\"-fast -xtarget=ultra\"; \
-	echo libs=\"-lpng17 -lz -lm\"; \
+	echo ccopts=\"-xtarget=ultra\"; \
+	echo ldopts=\"-xtarget=ultra\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config

--- a/scripts/makefile.64sunu
+++ b/scripts/makefile.64sunu
@@ -9,8 +9,8 @@
 # and license in png.h

 # Library name:
-LIBNAME=libpng17
-PNGMAJ = 17
+LIBNAME=libpng16
+PNGMAJ = 16

 # Shared library names:
 LIBSO=$(LIBNAME).so
@@ -29,7 +29,7 @@ RM_F=/bin/rm -f
 SUN_CC_FLAGS=-fast -xtarget=ultra -xarch=v9
 SUN_LD_FLAGS=-fast -xtarget=ultra -xarch=v9

-# where make install puts libpng.a, libpng17.so and libpng17/png.h
+# where make install puts libpng.a, libpng16.so and libpng16/png.h
 prefix=/a
 exec_prefix=$(prefix)

@@ -47,7 +47,7 @@ WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
 	-Wstrict-prototypes -Wmissing-prototypes #-Wconversion
 CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
 CFLAGS= $(SUN_CC_FLAGS) # $(WARNMORE) -g
-LDFLAGS=-L. -R. $(SUN_LD_FLAGS) -L$(ZLIBLIB) -R$(ZLIBLIB) -lpng17 -lz -lm
+LDFLAGS=-L. -R. $(SUN_LD_FLAGS) -L$(ZLIBLIB) -R$(ZLIBLIB) -lpng16 -lz -lm

 INCPATH=$(prefix)/include
 LIBPATH=$(exec_prefix)/lib
@@ -98,7 +98,7 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz\ -lm! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
@@ -107,9 +107,9 @@ libpng-config:
 	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
 	echo L_opts=\"-L$(LIBPATH)\"; \
 	echo R_opts=\"-R$(LIBPATH)\"; \
-	echo ccopts=\"-fast -xtarget=ultra -xarch=v9\"; \
-	echo ldopts=\"-fast -xtarget=ultra -xarch=v9\"; \
-	echo libs=\"-lpng17 -lz -lm\"; \
+	echo ccopts=\"-xtarget=ultra -xarch=v9\"; \
+	echo ldopts=\"-xtarget=ultra -xarch=v9\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config

--- a/scripts/makefile.aix
+++ b/scripts/makefile.aix
@@ -21,8 +21,8 @@ RANLIB = ranlib
 RM_F = rm -f
 LN_SF = ln -f -s

-LIBNAME = libpng17
-PNGMAJ = 17
+LIBNAME = libpng16
+PNGMAJ = 16

 prefix=/usr/local
 INCPATH=$(prefix)/include
@@ -44,7 +44,7 @@ DL=$(DESTDIR)$(LIBPATH)
 WARNMORE =
 CPPFLAGS = -I$(ZLIBINC) # -DPNG_DEBUG=5
 CFLAGS = -W -Wall -O2 # $(WARNMORE) -g
-LDFLAGS = -L. -L$(ZLIBLIB) -lpng17 -lz -lm
+LDFLAGS = -L. -L$(ZLIBLIB) -lpng16 -lz -lm

 # Variables
 OBJS =  png.o pngerror.o pngget.o pngmem.o pngpread.o \
--- a/scripts/makefile.bc32
+++ b/scripts/makefile.bc32
@@ -52,9 +52,7 @@ LDFLAGS=-L$(ZLIB_DIR) -M $(LDEBUG)

 # Pre-built configuration
 # See scripts\pnglibconf.mak for more options
-!ifndef PNGLIBCONF_H_PREBUILT
 PNGLIBCONF_H_PREBUILT = scripts\pnglibconf.h.prebuilt
-!endif

 ## Variables
 OBJS = \
--- a/scripts/makefile.beos
+++ b/scripts/makefile.beos
@@ -9,8 +9,8 @@
 # and license in png.h

 # Library name:
-LIBNAME=libpng17
-PNGMAJ = 17
+LIBNAME=libpng16
+PNGMAJ = 16

 # Shared library names:
 LIBSO=$(LIBNAME).so
@@ -46,7 +46,7 @@ CFLAGS=-W -Wall -O1 -funroll-loops $(ALIGN) # $(WARNMORE) -g
 # LDFLAGS=-L. -Wl,-rpath,. -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) -lpng -lz
 LDFLAGS=-L. -Wl,-soname=$(LIBSOMAJ) -L$(ZLIBLIB) -lz

-# where make install puts libpng.a, libpng17.so*, and png.h
+# where make install puts libpng.a, libpng16.so*, and png.h
 prefix=/usr/local
 exec_prefix=$(prefix)
 INCPATH=$(prefix)/include
@@ -98,13 +98,13 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz\ -lm! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
 	echo prefix=\"$(prefix)\"; \
 	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
-	echo libs=\"-lpng17 -lz \"; \
+	echo libs=\"-lpng16 -lz \"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config

@@ -117,7 +117,7 @@ $(LIBSOMAJ): $(OBJSDLL)
 	$(LIBSOMAJ) $(OBJSDLL) $(LDFLAGS)

 pngtest: pngtest.o $(LIBSO)
-	$(CC) -L$(ZLIBLIB) -L. -lz -lpng17 -o pngtest pngtest.o
+	$(CC) -L$(ZLIBLIB) -L. -lz -lpng16 -o pngtest pngtest.o

 test: pngtest
 	./pngtest
--- a/scripts/makefile.bor
+++ b/scripts/makefile.bor
@@ -60,9 +60,7 @@ LDFLAGS=-M -L$(ZLIB_DIR) $(MODEL_ARG) $(LDEBUG)

 # Pre-built configuration
 # See scripts\pnglibconf.mak for more options
-!ifndef PNGLIBCONF_H_PREBUILT
 PNGLIBCONF_H_PREBUILT = scripts\pnglibconf.h.prebuilt
-!endif

 ## Variables

--- a/scripts/makefile.cegcc
+++ b/scripts/makefile.cegcc
@@ -22,16 +22,16 @@
 # make clean

 VERMAJ = 1
-VERMIN = 7
-VERMIC = 0
+VERMIN = 6
+VERMIC = 13
 VER = $(VERMAJ).$(VERMIN).$(VERMIC)
 NAME = libpng
 PACKAGE = $(NAME)-$(VER)

-BIN = libpng17-0.dll
-LIB = libpng17.a libpng17.dll.a libpng.a libpng.dll.a
+BIN = libpng16-0.dll
+LIB = libpng16.a libpng16.dll.a libpng.a libpng.dll.a
 INCLUDE = png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-PC = libpng17.pc libpng.pc
+PC = libpng16.pc libpng.pc

 MANIFESTVERBIN = "Libpng-$(VER): Binary files"
 MANIFESTVERDEV = "Libpng-$(VER): Developer files"
--- a/scripts/makefile.darwin
+++ b/scripts/makefile.darwin
@@ -9,7 +9,7 @@
 # For conditions of distribution and use, see the disclaimer
 # and license in png.h

-# where "make install" puts libpng.a, libpng17.dylib, png.h, pngconf.h,
+# where "make install" puts libpng.a, libpng16.dylib, png.h, pngconf.h,
 # and pnglibconf.h
 prefix=/usr/local
 exec_prefix=$(prefix)
@@ -19,8 +19,8 @@ ZLIBLIB=/usr/lib
 ZLIBINC=/usr/include

 # Library name:
-LIBNAME = libpng17
-PNGMAJ = 17
+LIBNAME = libpng16
+PNGMAJ = 16

 # Shared library names:
 LIBSO=$(LIBNAME).dylib
@@ -36,11 +36,12 @@ LN_SF=ln -sf
 RANLIB=ranlib
 CP=cp
 RM_F=/bin/rm -f
+ARCH=-arch ppc -arch i386 -arch x86_64

 CPPFLAGS=-I$(ZLIBINC)
 # CFLAGS=-W -Wall -O3 -funroll-loops
-CFLAGS=-W -Wall -O -funroll-loops
-LDFLAGS=-L. -L$(ZLIBLIB) -lpng17 -lz
+CFLAGS=-W -Wall -O -funroll-loops $(ARCH)
+LDFLAGS=-L. -L$(ZLIBLIB) -lpng16 -lz $(ARCH)

 INCPATH=$(prefix)/include
 LIBPATH=$(exec_prefix)/lib
@@ -94,14 +95,14 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
 	echo prefix=\"$(prefix)\"; \
 	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
 	echo L_opts=\"-L$(LIBPATH)\"; \
-	echo libs=\"-lpng17 -lz\"; \
+	echo libs=\"-lpng16 -lz\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config

@@ -111,8 +112,8 @@ $(LIBSO): $(LIBSOMAJ)
 $(LIBSOMAJ): $(OBJSDLL)
 	$(CC) -dynamiclib \
 	 -install_name $(LIBPATH)/$(LIBSOMAJ) \
-	 -current_version 17 -compatibility_version 17 \
-	 -o $(LIBSOMAJ) \
+	 -current_version 16 -compatibility_version 16 \
+	 $(ARCH) -o $(LIBSOMAJ) \
 	 $(OBJSDLL) -L$(ZLIBLIB) -lz

 pngtest: pngtest.o $(LIBSO)
--- a/scripts/makefile.dec
+++ b/scripts/makefile.dec
@@ -7,8 +7,8 @@
 # and license in png.h

 # Library name:
-PNGMAJ = 17
-LIBNAME = libpng17
+PNGMAJ = 16
+LIBNAME = libpng16

 # Shared library names:
 LIBSO=$(LIBNAME).so
@@ -83,7 +83,7 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz\ -lm! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
@@ -91,7 +91,7 @@ libpng-config:
 	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
 	echo ccopts=\"-std\"; \
 	echo L_opts=\"-L$(LIBPATH)\"; \
-	echo libs=\"-lpng17 -lz -lm\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config

--- a/scripts/makefile.freebsd
+++ b/scripts/makefile.freebsd
@@ -7,7 +7,7 @@
 # and license in png.h

 PREFIX?=        /usr/local
-SHLIB_VER?=     17
+SHLIB_VER?=     16

 LIB=		png
 SHLIB_MAJOR=	${SHLIB_VER}
--- a/scripts/makefile.hp64
+++ b/scripts/makefile.hp64
@@ -19,8 +19,8 @@ ZLIBINC=/opt/zlib/include
 #   SHAREDLIB=libz.sl

 # Library name:
-LIBNAME = libpng17
-PNGMAJ = 17
+LIBNAME = libpng16
+PNGMAJ = 16

 # Shared library names:
 LIBSO=$(LIBNAME).sl
@@ -45,7 +45,7 @@ CCFLAGS=-O -Ae -Wl,+vnocompatwarnings +DD64 +Z

 LDFLAGS=-L. -L$(ZLIBLIB) -lpng -lz -lm

-# where make install puts libpng.a, libpng17.sl, and png.h
+# where make install puts libpng.a, libpng16.sl, and png.h
 prefix=/opt/libpng
 exec_prefix=$(prefix)
 INCPATH=$(prefix)/include
@@ -100,15 +100,15 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz\ -lm! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
 	echo prefix=\"$(prefix)\"; \
 	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
-	echo ccopts=\"-O -Ae -Wl,+vnocompatwarnings +DD64 +Z\"; \
+	echo ccopts=\"-Ae +DA1.1 +DS2.0\"; \
 	echo L_opts=\"-L$(LIBPATH)\"; \
-	echo libs=\"-lpng17 -lz -lm\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config

--- a/scripts/makefile.hpgcc
+++ b/scripts/makefile.hpgcc
@@ -9,8 +9,8 @@
 # and license in png.h

 # Library name:
-LIBNAME = libpng17
-PNGMAJ = 17
+LIBNAME = libpng16
+PNGMAJ = 16

 # Shared library names:
 LIBSO=$(LIBNAME).sl
@@ -56,8 +56,8 @@ WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \

 CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
 CFLAGS=-W -Wall -O3 -funroll-loops $(ALIGN) # $(WARNMORE) -g
-#LDFLAGS=-L. -Wl,-rpath,. -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) -lpng17 -lz -lm
-LDFLAGS=-L. -L$(ZLIBLIB) -lpng17 -lz -lm
+#LDFLAGS=-L. -Wl,-rpath,. -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) -lpng16 -lz -lm
+LDFLAGS=-L. -L$(ZLIBLIB) -lpng16 -lz -lm

 INCPATH=$(prefix)/include
 LIBPATH=$(exec_prefix)/lib
@@ -104,13 +104,13 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz\ -lm! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
 	echo prefix=\"$(prefix)\"; \
 	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
-	echo libs=\"-lpng17 -lz -lm\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config

--- a/scripts/makefile.hpux
+++ b/scripts/makefile.hpux
@@ -20,8 +20,8 @@ ZLIBINC=/opt/zlib/include
 #   SHAREDLIB=libz.sl

 # Library name:
-LIBNAME = libpng17
-PNGMAJ = 17
+LIBNAME = libpng16
+PNGMAJ = 16

 # Shared library names:
 LIBSO=$(LIBNAME).sl
@@ -37,7 +37,7 @@ LN_SF=ln -sf
 RANLIB=ranlib
 RM_F=/bin/rm -f

-# where make install puts libpng.a, libpng17.sl, and png.h
+# where make install puts libpng.a, libpng16.sl, and png.h
 prefix=/opt/libpng
 exec_prefix=$(prefix)
 INCPATH=$(prefix)/include
@@ -98,15 +98,15 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz\ -lm! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
 	echo prefix=\"$(prefix)\"; \
 	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
-	echo ccopts=\"-O -Ae +DA1.1 +DS2.0\"; \
+	echo ccopts=\"-Ae +DA1.1 +DS2.0\"; \
 	echo L_opts=\"-L$(LIBPATH)\"; \
-	echo libs=\"-lpng17 -lz -lm\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config

--- a/scripts/makefile.linux
+++ b/scripts/makefile.linux
@@ -1,4 +1,4 @@
-# makefile for libpng.a and libpng17.so on Linux ELF with gcc
+# makefile for libpng.a and libpng16.so on Linux ELF with gcc
 # Copyright (C) 1998, 1999, 2002, 2006, 2008, 2010-2014 Greg Roelofs and
 # Glenn Randers-Pehrson
 # Copyright (C) 1996, 1997 Andreas Dilger
@@ -8,9 +8,9 @@
 # and license in png.h

 # Library name:
-LIBNAME = libpng17
-PNGMAJ = 17
-RELEASE = 0
+LIBNAME = libpng16
+PNGMAJ = 16
+RELEASE = 13

 # Shared library names:
 LIBSO=$(LIBNAME).so
@@ -27,8 +27,8 @@ RANLIB=ranlib
 CP=cp
 RM_F=/bin/rm -f

-# where "make install" puts libpng17.a, libpng17.so*,
-# libpng17/png.h, libpng17/pngconf.h, and libpng17/pnglibconf.h
+# where "make install" puts libpng16.a, libpng16.so*,
+# libpng16/png.h, libpng16/pngconf.h, and libpng16/pnglibconf.h
 # Prefix must be a full pathname.
 prefix=/usr/local
 exec_prefix=$(prefix)
@@ -53,7 +53,7 @@ CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
 CFLAGS= -W -Wall -O3 -funroll-loops \
 	$(ALIGN) # $(WARNMORE) -g -DPNG_DEBUG=5

-LDFLAGS=-L. -Wl,-rpath,. -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) -lpng17 -lz -lm
+LDFLAGS=-L. -Wl,-rpath,. -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) -lpng16 -lz -lm
 LDFLAGS_A=-L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) libpng.a -lz -lm

 INCPATH=$(prefix)/include
@@ -108,7 +108,7 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz\ -lm! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
@@ -116,7 +116,7 @@ libpng-config:
 	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
 	echo L_opts=\"-L$(LIBPATH)\"; \
 	echo R_opts=\"-Wl,-rpath,$(LIBPATH)\"; \
-	echo libs=\"-lpng17 -lz -lm\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config

--- a/scripts/makefile.msys
+++ b/scripts/makefile.msys
@@ -16,9 +16,9 @@ prefix=/usr/local
 exec_prefix=$(prefix)

 # Library name:
-LIBNAME = libpng17
-PNGMAJ = 17
-RELEASE = 0
+LIBNAME = libpng16
+PNGMAJ = 16
+RELEASE = 13

 # Shared library names:
 LIBSO=$(LIBNAME).dll
@@ -126,7 +126,7 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz\ -lm! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
@@ -134,7 +134,7 @@ libpng-config:
 	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
 	echo L_opts=\"-L$(LIBPATH)\"; \
 	echo R_opts=\"-Wl,-rpath,$(LIBPATH)\"; \
-	echo libs=\"-lpng17 -lz -lm\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config

 install-shared: install-headers $(LIBSOMAJ) libpng.pc
--- a/scripts/makefile.ne12bsd
+++ b/scripts/makefile.ne12bsd
@@ -13,11 +13,11 @@
 LOCALBASE?=/usr/local
 LIBDIR=	${LOCALBASE}/lib
 MANDIR= ${LOCALBASE}/man
-INCSDIR=${LOCALBASE}/include/libpng17
+INCSDIR=${LOCALBASE}/include/libpng16

-LIB=	png17
+LIB=	png16
 SHLIB_MAJOR=	0
-SHLIB_MINOR=	1.7.0beta52
+SHLIB_MINOR=	1.6.13beta04
 SRCS=	png.c pngset.c pngget.c pngrutil.c pngtrans.c pngwutil.c \
 	pngread.c pngrio.c pngwio.c pngwrite.c pngrtran.c \
 	pngwtran.c pngmem.c pngerror.c pngpread.c
--- a/scripts/makefile.netbsd
+++ b/scripts/makefile.netbsd
@@ -8,7 +8,7 @@
 # For conditions of distribution and use, see the disclaimer
 # and license in png.h

-# You should also run makefile.ne17bsd
+# You should also run makefile.ne16bsd

 LOCALBASE?=/usr/local
 LIBDIR=	${LOCALBASE}/lib
@@ -16,8 +16,8 @@ MANDIR= ${LOCALBASE}/man
 INCSDIR=${LOCALBASE}/include

 LIB=	png
-SHLIB_MAJOR=	17
-SHLIB_MINOR=	1.7.0beta52
+SHLIB_MAJOR=	16
+SHLIB_MINOR=	1.6.13beta04
 SRCS=	png.c pngset.c pngget.c pngrutil.c pngtrans.c pngwutil.c \
 	pngread.c pngrio.c pngwio.c pngwrite.c pngrtran.c \
 	pngwtran.c pngmem.c pngerror.c pngpread.c
--- a/scripts/makefile.openbsd
+++ b/scripts/makefile.openbsd
@@ -10,8 +10,8 @@ PREFIX?= /usr/local
 LIBDIR=	${PREFIX}/lib
 MANDIR= ${PREFIX}/man/cat

-SHLIB_MAJOR=	17
-SHLIB_MINOR=	1.7.0beta52
+SHLIB_MAJOR=	16
+SHLIB_MINOR=	1.6.13beta04

 LIB=	png
 SRCS=	png.c pngerror.c pngget.c pngmem.c pngpread.c \
--- a/scripts/makefile.sco
+++ b/scripts/makefile.sco
@@ -10,8 +10,8 @@
 # and license in png.h

 # Library name:
-LIBNAME = libpng17
-PNGMAJ = 17
+LIBNAME = libpng16
+PNGMAJ = 16

 # Shared library names:
 LIBSO=$(LIBNAME).so
@@ -40,7 +40,7 @@ ZLIBINC=../zlib

 CPPFLAGS=-I$(ZLIBINC)
 CFLAGS= -dy -belf -O3
-LDFLAGS=-L. -L$(ZLIBLIB) -lpng17 -lz -lm
+LDFLAGS=-L. -L$(ZLIBLIB) -lpng16 -lz -lm

 INCPATH=$(prefix)/include
 LIBPATH=$(exec_prefix)/lib
@@ -94,7 +94,7 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz\ -lm! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
@@ -102,7 +102,7 @@ libpng-config:
 	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
 	echo ccopts=\"-belf\"; \
 	echo L_opts=\"-L$(LIBPATH)\"; \
-	echo libs=\"-lpng17 -lz -lm\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config

--- a/scripts/makefile.sggcc
+++ b/scripts/makefile.sggcc
@@ -1,4 +1,4 @@
-# makefile for libpng.a and libpng17.so, SGI IRIX with 'cc'
+# makefile for libpng.a and libpng16.so, SGI IRIX with 'cc'
 # Copyright (C) 2001-2002, 2006, 2010-2014 Glenn Randers-Pehrson
 # Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
 #
@@ -7,8 +7,8 @@
 # and license in png.h

 # Library name:
-LIBNAME=libpng17
-PNGMAJ = 17
+LIBNAME=libpng16
+PNGMAJ = 16

 # Shared library names:
 LIBSO=$(LIBNAME).so
@@ -25,7 +25,7 @@ RANLIB=echo
 CP=cp
 RM_F=/bin/rm -f

-# Where make install puts libpng.a, libpng17.so, and libpng17/png.h
+# Where make install puts libpng.a, libpng16.so, and libpng16/png.h
 # Prefix must be a full pathname.

 prefix=/usr/local
@@ -99,7 +99,7 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz\ -lm! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
@@ -110,7 +110,7 @@ libpng-config:
 	echo ldopts=\"$(ABI)\"; \
 	echo L_opts=\"-L$(LIBPATH)\"; \
 	echo libdir=\"$(LIBPATH)\"; \
-	echo libs=\"-lpng17 -lz -lm\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config

--- a/scripts/makefile.sgi
+++ b/scripts/makefile.sgi
@@ -1,4 +1,4 @@
-# makefile for libpng.a and libpng17.so, SGI IRIX with 'cc'
+# makefile for libpng.a and libpng16.so, SGI IRIX with 'cc'
 # Copyright (C) 2001-2002, 2006, 2007, 2010-2014 Glenn Randers-Pehrson
 # Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
 #
@@ -7,8 +7,8 @@
 # and license in png.h

 # Library name:
-LIBNAME=libpng17
-PNGMAJ = 17
+LIBNAME=libpng16
+PNGMAJ = 16

 # Shared library names:
 LIBSO=$(LIBNAME).so
@@ -25,7 +25,7 @@ RANLIB=echo
 CP=cp
 RM_F=/bin/rm -f

-# Where make install puts libpng.a, libpng17.so, and libpng17/png.h
+# Where make install puts libpng.a, libpng16.so, and libpng16/png.h
 # Prefix must be a full pathname.

 prefix=/usr/local
@@ -48,7 +48,7 @@ WARNMORE=-fullwarn
 CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
 #CFLAGS= $(ABI) -O $(WARNMORE) -KPIC # -g
 CFLAGS=$(ABI) -O $(WARNMORE)
-LDFLAGS_A=$(ABI) -L. -L$(ZLIBLIB) -lpng17 -lz -lm
+LDFLAGS_A=$(ABI) -L. -L$(ZLIBLIB) -lpng16 -lz -lm
 LDFLAGS=$(ABI) -L. -L$(ZLIBLIB) -lpng -lz -lm
 LDSHARED=cc $(ABI) -shared -soname $(LIBSOMAJ) \
 	-set_version sgi$(PNGMAJ).0
@@ -100,7 +100,7 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz\ -lm! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
@@ -110,7 +110,7 @@ libpng-config:
 	echo ldopts=\"$(ABI)\"; \
 	echo L_opts=\"-L$(LIBPATH)\"; \
 	echo libdir=\"$(LIBPATH)\"; \
-	echo libs=\"-lpng17 -lz -lm\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config

--- a/scripts/makefile.so9
+++ b/scripts/makefile.so9
@@ -10,8 +10,8 @@
 # and license in png.h

 # Library name:
-PNGMAJ = 17
-LIBNAME = libpng17
+PNGMAJ = 16
+LIBNAME = libpng16

 # Shared library names:
 LIBSO=$(LIBNAME).so
@@ -50,7 +50,7 @@ ZLIBINC=/usr/include
 CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
 #CFLAGS=-W -Wall -O3 $(WARNMORE) -g
 CFLAGS=-O3
-LDFLAGS=-L. -R. -L$(ZLIBLIB) -R$(ZLIBLIB) -lpng17 -lz -lm
+LDFLAGS=-L. -R. -L$(ZLIBLIB) -R$(ZLIBLIB) -lpng16 -lz -lm

 INCPATH=$(prefix)/include
 LIBPATH=$(exec_prefix)/lib
@@ -104,7 +104,7 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz\ -lm! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
@@ -112,7 +112,7 @@ libpng-config:
 	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
 	echo L_opts=\"-L$(LIBPATH)\"; \
 	echo R_opts=\"-R$(LIBPATH)\"; \
-	echo libs=\"-lpng17 -lz -lm\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config

--- a/scripts/makefile.solaris
+++ b/scripts/makefile.solaris
@@ -9,8 +9,8 @@
 # and license in png.h

 # Library name:
-LIBNAME = libpng17
-PNGMAJ = 17
+LIBNAME = libpng16
+PNGMAJ = 16

 # Shared library names:
 LIBSO=$(LIBNAME).so
@@ -27,7 +27,7 @@ RANLIB=echo
 CP=cp
 RM_F=/bin/rm -f

-# Where make install puts libpng.a, libpng17.so*, and png.h
+# Where make install puts libpng.a, libpng16.so*, and png.h
 prefix=/usr/local
 exec_prefix=$(prefix)

@@ -46,7 +46,7 @@ WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
 CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
 CFLAGS= -W -Wall -O \
 	# $(WARNMORE) -g -DPNG_DEBUG=5
-LDFLAGS=-L. -R. -L$(ZLIBLIB) -R$(ZLIBLIB) -lpng17 -lz -lm
+LDFLAGS=-L. -R. -L$(ZLIBLIB) -R$(ZLIBLIB) -lpng16 -lz -lm

 INCPATH=$(prefix)/include
 LIBPATH=$(exec_prefix)/lib
@@ -100,7 +100,7 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz\ -lm! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
@@ -109,7 +109,7 @@ libpng-config:
 	echo cppflags=\"\"; \
 	echo L_opts=\"-L$(LIBPATH)\"; \
 	echo R_opts=\"-R$(LIBPATH)\"; \
-	echo libs=\"-lpng17 -lz -lm\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config

--- a/Show More
+++ b/Show More