[master] Imported from libpng-1.6.16.tar

[master] Imported from libpng-1.6.15.tar
[master] Imported from libpng-1.6.14.tar
2025-07-10 18:04:09 +02:00 · 2015-01-15 12:47:40 -05:00 · 2014-11-20 10:23:30 -06:00 · 2014-10-22 19:33:27 -05:00 · 2014-08-21 05:59:56 -05:00 · 2014-06-11 20:42:07 -05:00
73 changed files with 1731 additions and 1354 deletions
--- a/66
+++ b/66
@@ -1,66 +1,36 @@
-Libpng 1.6.14beta06 - October 5, 2014
+Libpng 1.6.16 - December 22, 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.
+This is a public release of libpng, intended for use in production codes.

 Files available for download:

 Source files with LF line endings (for Unix/Linux) and with a
 "configure" script

-   1.6.14beta06.tar.xz (LZMA-compressed, recommended)
-   1.6.14beta06.tar.gz
+   libpng-1.6.16.tar.xz (LZMA-compressed, recommended)
+   libpng-1.6.16.tar.gz

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

-   lp1614b06.7z  (LZMA-compressed, recommended)
-   lp1614b06.zip
+   lpng1616.7z  (LZMA-compressed, recommended)
+   lpng1616.zip

 Other information:

-   1.6.14beta06-README.txt
-   1.6.14beta06-LICENSE.txt
-   libpng-1.6.14beta06-*.asc (armored detached GPG signatures)
+   libpng-1.6.16-README.txt
+   libpng-1.6.16-LICENSE.txt
+   libpng-1.6.16-*.asc (armored detached GPG signatures)

-Changes since the last public release (1.6.13):
-
-Version 1.6.14beta01 [September 14, 2014]
-  Guard usage of png_ptr->options with #ifdef PNG_SET_OPTION_SUPPORTED.
-  Do not build contrib/tools/pngfix.c when PNG_SETJMP_NOT_SUPPORTED,
-    to allow "make" to complete without setjmp support (bug report by
-    Claudio Fontana)
-  Add "#include <setjmp.h>" to contrib/tools/pngfix.c (John Bowler)
-
-Version 1.6.14beta02 [September 18, 2014]
-  Use nanosleep() instead of usleep() in contrib/gregbook/rpng2-x.c
-    because usleep() is deprecated.
-  Define usleep() in contrib/gregbook/rpng2-x.c if not already defined
-    in unistd.h and nanosleep() is not available; fixes error introduced
-    in libpng-1.6.13.
-  Disable floating point exception handling in pngvalid.c when
-    PNG_FLOATING_ARITHMETIC is not supported (bug report by "zootus
-    at users.sourceforge.net").
-
-Version 1.6.14beta03 [September 19, 2014]
-  Define FE_DIVBYZERO, FE_INVALID, and FE_OVERFLOW in pngvalid.c if not
-    already defined.  Revert floating point exception handling in pngvalid.c
-    to version 1.6.14beta01 behavior.
-
-Version 1.6.14beta04 [September 27, 2014]
-  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 1.6.14beta05 [October 1, 2014]
-  Added "option READ_iCCP enables READ_COMPRESSED_TEXT" to pnglibconf.dfa
-
-Version 1.6.14beta06 [October 5, 2014]
-  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.
+Changes since the last public release (1.6.15):
+  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).
+  Restored a test on width that was removed from png.c at libpng-1.6.9
+    (Bug report by Alex Eubanks).
+  Fixed an overflow in png_combine_row with very wide interlaced images.

 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
--- a/110
+++ b/110
@@ -5014,6 +5014,116 @@ Version 1.6.14beta06 [October 5, 2014]
  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.
+
+Version 1.6.14beta07 [October 7, 2014]
+  Removed "option WRITE_COMPRESSED_TEXT enables WRITE_TEXT" from pnglibconf.dfa
+  Only mark text chunks as written after successfully writing them.
+
+Version 1.6.14rc01 [October 15, 2014]
+  Fixed some typos in comments.
+
+Version 1.6.14rc02 [October 17, 2014]
+  Changed png_convert_to_rfc_1123() to png_convert_to_rfc_1123_buffer()
+    in the manual, to reflect the change made in libpng-1.6.0.
+  Updated README file to explain that direct access to the png_struct
+    and info_struct members has not been permitted since libpng-1.5.0.
+
+Version 1.6.14 [October 23, 2014]
+  No changes.
+
+Version 1.6.15beta01 [October 29, 2014]
+  Changed "if (!x)" to "if (x == 0)" and "if (x)" to "if (x != 0)"
+  Simplified png_free_data().
+  Added missing "ptr = NULL" after some instances of png_free().
+
+Version 1.6.15beta02 [November 1, 2014]
+  Changed remaining "if (!x)" to "if (x == 0)" and "if (x)" to "if (x != 0)"
+
+Version 1.6.15beta03 [November 3, 2014]
+  Added PNG_USE_ARM_NEON configuration flag (Marcin Juszkiewicz).
+
+Version 1.6.15beta04 [November 4, 2014]
+  Removed new PNG_USE_ARM_NEON configuration flag and made a one-line
+    revision to configure.ac to support ARM on aarch64 instead (John Bowler).
+
+Version 1.6.15beta05 [November 5, 2014]
+  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 1.6.15beta06 [November 6, 2014]
+  Reverted use png_get_libpng_ver(NULL) instead of PNG_LIBPNG_VER_STRING
+    in the manual, example.c, pngtest.c, and applications in the contrib
+    directory.  It was incorrect advice.
+
+Version 1.6.15beta07 [November 7, 2014]
+  Removed #ifdef PNG_16BIT_SUPPORTED/#endif around png_product2(); it is
+    needed by png_reciprocal2().
+  Added #ifdef PNG_16BIT_SUPPORTED/#endif around png_log16bit() and
+    png_do_swap().
+  Changed all "#endif /* PNG_FEATURE_SUPPORTED */" to "#endif /* FEATURE */"
+
+Version 1.6.15beta08 [November 8, 2014]
+  More housecleaning in *.h
+
+Version 1.6.15rc01 [November 13, 2014]
+
+Version 1.6.15rc02 [November 14, 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).
+
+Version 1.6.15rc03 [November 16, 2014]
+  Added "-D_CRT_SECURE_NO_WARNINGS" to CFLAGS in scripts/makefile.vcwin32.
+  Removed the obsolete $ARCH variable from scripts/makefile.darwin.
+
+Version 1.6.15 [November 20, 2014]
+  No changes.
+
+Version 1.6.16beta01 [December 14, 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/symbols.dfn to work with MinGW/MSYS
+    (Bob Friesenhahn).
+
+Version 1.6.16beta02 [December 15, 2014]
+  Revised Makefile.am and scripts/*.dfn again to work with MinGW/MSYS;
+    renamed scripts/*.dfn to scripts/*.c (John Bowler).
+
+Version 1.6.16beta03 [December 21, 2014]
+  Quiet a "comparison always true" warning in pngstest.c (John Bowler).
+
+Version 1.6.16rc01 [December 21, 2014]
+  Restored a test on width that was removed from png.c at libpng-1.6.9
+    (Bug report by Alex Eubanks).
+
+Version 1.6.16rc02 [December 21, 2014]
+  Undid the update to pngrutil.c in 1.6.16rc01.
+
+Version 1.6.16rc03 [December 21, 2014]
+  Fixed an overflow in png_combine_row with very wide interlaced images.
+
+Version 1.6.16 [December 22, 2014]
+  No changes.

 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -16,7 +16,7 @@ enable_testing()

 set(PNGLIB_MAJOR 1)
 set(PNGLIB_MINOR 6)
-set(PNGLIB_RELEASE 14)
+set(PNGLIB_RELEASE 16)
 set(PNGLIB_NAME libpng${PNGLIB_MAJOR}${PNGLIB_MINOR})
 set(PNGLIB_VERSION ${PNGLIB_MAJOR}.${PNGLIB_MINOR}.${PNGLIB_RELEASE})

@@ -253,7 +253,7 @@ endif(NOT WIN32 OR CYGWIN OR MINGW)
 # SET UP LINKS
 if(PNG_SHARED)
  set_target_properties(${PNG_LIB_NAME} PROPERTIES
-#   VERSION 16.${PNGLIB_RELEASE}.1.6.14beta06
+#   VERSION 16.${PNGLIB_RELEASE}.1.6.16
    VERSION 16.${PNGLIB_RELEASE}.0
    SOVERSION 16
    CLEAN_DIRECT_OUTPUT 1)
--- a/35
+++ b/35
@@ -18,7 +18,7 @@ VIII. Configuring libpng for 16-bit platforms
 XIII. Removing unwanted object code
 XIV. Changes to the build and configuration of libpng in libpng-1.5.x
  XV. Configuring libpng for multiprocessing
- XVI. Other sources of information about libpng:
+ XVI. Other sources of information about libpng

 I. Simple installation

@@ -32,6 +32,15 @@ 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
@@ -111,8 +120,7 @@ Your directory structure should look like this:
      libpng  (this directory)
          INSTALL (this file)
          README
-          *.h
-          *.c
+          *.h, *.c  => libpng source files
          CMakeLists.txt    =>  "cmake" script
          configuration files:
             configure.ac, configure, Makefile.am, Makefile.in,
@@ -120,15 +128,10 @@ 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
-             gregbook
-             libtests
-             pngminim
-             pngminus
-             pngsuite
-             visupng
+             arm-neon, conftest, examples, gregbook, libtests, pngminim,
+             pngminus, pngsuite, tools, visupng
          projects
-             visualc71
-             vstudio
+             cbuilder5, owatcom, visualc71, vstudio, xcode
          scripts
             makefile.*
             *.def (module definition files)
@@ -136,11 +139,7 @@ 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
@@ -149,7 +148,7 @@ 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\visualc6 or visualc71 directory and follow the instructions
+libpng projects\visualc71 or vstudio directory and follow the instructions
 in README.txt.

 Otherwise enter the zlib directory and follow the instructions in zlib/README,
@@ -395,7 +394,7 @@ 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/libpng%NN%, or whatever.
+/usr/include/libpng16, 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/4
+++ b/4
@@ -10,7 +10,7 @@ this sentence.

 This code is released under the libpng license.

-libpng versions 1.2.6, August 15, 2004, through 1.6.14beta06, October 5, 2014, are
+libpng versions 1.2.6, August 15, 2004, through 1.6.16, December 22, 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
-October 5, 2014
+December 22, 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.dfn
+SCRIPT_CLEANFILES=scripts/*.out scripts/*.chk scripts/pnglibconf.c

 CLEANFILES= *.tf? pngout.png libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.pc \
 	libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config libpng.vers libpng.sym \
@@ -152,7 +152,7 @@ AM_CFLAGS = ${PNG_COPTS}
 # checks for this and sets DFNCPP appropriately.
 DFNCPP = @DFNCPP@

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

 $(PNGLIB_BASENAME).pc: libpng.pc
 	cp libpng.pc $@
@@ -237,18 +237,17 @@ if DO_PNG_PREFIX
 SYMBOL_CFLAGS += -DPNG_PREFIX='@PNG_PREFIX@'
 endif

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

-# The .dfn file for pnglibconf.h is machine generated
-pnglibconf.dfn: scripts/pnglibconf.dfa scripts/options.awk pngconf.h pngusr.dfa $(DFA_XTRA)
+# The .c file for pnglibconf.h is machine generated
+pnglibconf.c: 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\
@@ -268,7 +267,7 @@ 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.dfn: scripts/pnglibconf.dfa scripts/options.awk pngconf.h
+scripts/pnglibconf.c: 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 1.6.14beta06 - October 5, 2014 (shared library 16.0)
+README for libpng version 1.6.16 - December 22, 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.
@@ -23,18 +23,25 @@ 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 do not make current programs
+It is important to note that the APIs did not make current programs
 that access the info struct directly incompatible with the new
-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.
+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.
 ****

 Additions since 0.90 include the ability to compile libpng as a
@@ -183,7 +190,7 @@ 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 1.6.10 [March 6, 2014]
+ * Last changed in libpng 1.6.16 [December 22, 2014]
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
@@ -17,6 +17,7 @@
 #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
@@ -130,4 +131,4 @@ png_init_filter_functions_neon(png_structp pp, unsigned int bpp)
   }
 }
 #endif /* PNG_ARM_NEON_OPT > 0 */
-#endif /* PNG_READ_SUPPORTED */
+#endif /* READ */
--- a/arm/filter_neon.S
+++ b/arm/filter_neon.S
@@ -1,18 +1,17 @@

 /* filter_neon.S - NEON optimised filter functions
 *
- * Copyright (c) 2013 Glenn Randers-Pehrson
+ * Copyright (c) 2014 Glenn Randers-Pehrson
 * Written by Mans Rullgard, 2011.
- * Last changed in libpng 1.6.8 [December 19, 2013]
+ * Last changed in libpng 1.6.16 [December 22, 2014]
 *
 * 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 also
- * includes the definition (or not) of PNG_ARM_NEON_OPT and
- * PNG_ARM_NEON_IMPLEMENTATION.
+/* 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.
 */
 #define PNG_VERSION_INFO_ONLY
 #include "../pngpriv.h"
@@ -21,6 +20,8 @@
 .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
@@ -28,7 +29,6 @@
 */
 #if PNG_ARM_NEON_IMPLEMENTATION == 2 /* hand-coded assembler */

-#ifdef PNG_READ_SUPPORTED
 #if PNG_ARM_NEON_OPT > 0

 #ifdef __ELF__
@@ -47,6 +47,13 @@ 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
@@ -242,5 +249,5 @@ 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) 2013 Glenn Randers-Pehrson
+ * Copyright (c) 2014 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 1.6.8 [December 19, 2013]
+ * Last changed in libpng 1.6.16 [December 22, 2014]
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
@@ -14,6 +14,8 @@

 #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 */

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

-#ifdef PNG_READ_SUPPORTED
 #if PNG_ARM_NEON_OPT > 0

 void
@@ -368,5 +369,5 @@ 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],[1.6.14beta06],[png-mng-implement@lists.sourceforge.net])
+AC_INIT([libpng],[1.6.16],[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=1.6.14beta06
+PNGLIB_VERSION=1.6.16
 PNGLIB_MAJOR=1
 PNGLIB_MINOR=6
-PNGLIB_RELEASE=14
+PNGLIB_RELEASE=16

 dnl End of version number stuff

@@ -310,7 +310,7 @@ AC_ARG_ENABLE([arm-neon],
 AM_CONDITIONAL([PNG_ARM_NEON],
   [test "$enable_arm_neon" != 'no' &&
    case "$host_cpu" in
-      arm*) :;;
+      arm*|aarch64*) :;;
      *)    test "$enable_arm_neon" != '';;
    esac])

--- 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 1.6.10 [March 6, 2014]
+ * Last changed in libpng 1.6.16 [December 22, 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 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 it assumes that /proc/cpuinfo is never localized.
 */
 #include <stdio.h>

@@ -152,8 +152,10 @@ 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/readpng.c
+++ b/contrib/gregbook/readpng.c
@@ -100,7 +100,8 @@ int readpng_init(FILE *infile, ulg *pWidth, ulg *pHeight)

    /* could pass pointers to user-defined error handlers instead of NULLs: */

-    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+    png_ptr = png_create_read_struct(png_get_libpng_ver(NULL), NULL, NULL,
+        NULL);
    if (!png_ptr)
        return 4;   /* out of memory */

--- a/contrib/gregbook/readpng2.c
+++ b/contrib/gregbook/readpng2.c
@@ -104,7 +104,7 @@ int readpng2_init(mainprog_info *mainprog_ptr)

    /* could also replace libpng warning-handler (final NULL), but no need: */

-    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, mainprog_ptr,
+    png_ptr = png_create_read_struct(png_get_libpng_ver(NULL), mainprog_ptr,
      readpng2_error_handler, readpng2_warning_handler);
    if (!png_ptr)
        return 4;   /* out of memory */
--- a/contrib/gregbook/writepng.c
+++ b/contrib/gregbook/writepng.c
@@ -90,7 +90,7 @@ int writepng_init(mainprog_info *mainprog_ptr)

    /* could also replace libpng warning-handler (final NULL), but no need: */

-    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, mainprog_ptr,
+    png_ptr = png_create_write_struct(png_get_libpng_ver(NULL), mainprog_ptr,
      writepng_error_handler, NULL);
    if (!png_ptr)
        return 4;   /* out of memory */
--- a/contrib/libtests/pngimage.c
+++ b/contrib/libtests/pngimage.c
@@ -337,6 +337,9 @@ 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 */
@@ -361,6 +364,25 @@ 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)
@@ -390,8 +412,6 @@ 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)
 {
@@ -598,6 +618,17 @@ 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 */
@@ -1605,6 +1636,9 @@ 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 John Cunningham Bowler
+ * Copyright (c) 2013-2014 John Cunningham Bowler
 *
- * Last changed in libpng 1.6.8 [December 19, 2013]
+ * Last changed in libpng 1.6.16 [December 22, 2014]
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
@@ -3173,32 +3173,43 @@ read_one_file(Image *image)
            {
               long int cb = ftell(f);

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

-                     if (fread(b, (size_t)cb, 1, f) == 1)
+                     if (b != NULL)
                     {
-                        fclose(f);
-                        image->input_memory_size = cb;
-                        image->input_memory = b;
+                        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: ");
+                        }
                     }

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

                  else
                     return logclose(image, f, image->file_name,
-                        ": out of memory: ");
+                        ": 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.
+                      */
               }

               else if (cb == 0)
--- a/contrib/libtests/pngvalid.c
+++ b/contrib/libtests/pngvalid.c
@@ -1,7 +1,7 @@

 /* pngvalid.c - validate libpng by constructing then reading png files.
 *
- * Last changed in libpng 1.6.14 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.14 [October 23, 2014]
 * Copyright (c) 2014 Glenn Randers-Pehrson
 * Written by John Cunningham Bowler
 *
@@ -157,6 +157,13 @@ define_exception_type(struct png_store*);
   &(ps)->exception_context
 #define context(ps,fault) anon_context(ps); png_store *fault

+/* This macro returns the number of elements in an array as an (unsigned int),
+ * it is necessary to avoid the inability of certain versions of GCC to use
+ * the value of a compile-time constant when performing range checks.  It must
+ * be passed an array name.
+ */
+#define ARRAY_SIZE(a) ((unsigned int)((sizeof (a))/(sizeof (a)[0])))
+
 /******************************* UTILITIES ************************************/
 /* Error handling is particularly problematic in production code - error
 * handlers often themselves have bugs which lead to programs that detect
@@ -1558,7 +1565,7 @@ set_store_for_write(png_store *ps, png_infopp ppi,

         else
 #     endif
-         ps->pwrite = png_create_write_struct(PNG_LIBPNG_VER_STRING,
+         ps->pwrite = png_create_write_struct(png_get_libpng_ver(NULL),
            ps, store_error, store_warning);

      png_set_write_fn(ps->pwrite, ps, store_write, store_flush);
@@ -4106,7 +4113,7 @@ make_errors(png_modifier* PNG_CONST pm, png_byte PNG_CONST colour_type,
         standard_name(name, sizeof name, 0, colour_type, 1<<bdlo, 0,
            interlace_type, 0, 0, 0);

-         for (test=0; test<(sizeof error_test)/(sizeof error_test[0]); ++test)
+         for (test=0; test<ARRAY_SIZE(error_test); ++test)
         {
            make_error(&pm->this, colour_type, DEPTH(bdlo), interlace_type,
               test, name);
@@ -10098,12 +10105,12 @@ int main(int argc, char **argv)

   /* Store the test gammas */
   pm.gammas = gammas;
-   pm.ngammas = (sizeof gammas) / (sizeof gammas[0]);
+   pm.ngammas = ARRAY_SIZE(gammas);
   pm.ngamma_tests = 0; /* default to off */

   /* And the test encodings */
   pm.encodings = test_encodings;
-   pm.nencodings = (sizeof test_encodings) / (sizeof test_encodings[0]);
+   pm.nencodings = ARRAY_SIZE(test_encodings);

   pm.sbitlow = 8U; /* because libpng doesn't do sBIT below 8! */

--- a/contrib/pngminus/png2pnm.c
+++ b/contrib/pngminus/png2pnm.c
@@ -223,7 +223,7 @@ BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file,

  /* create png and info structures */

-  png_ptr = png_create_read_struct (PNG_LIBPNG_VER_STRING,
+  png_ptr = png_create_read_struct (png_get_libpng_ver(NULL),
    NULL, NULL, NULL);
  if (!png_ptr)
    return FALSE;   /* out of memory */
--- a/contrib/pngminus/pnm2png.c
+++ b/contrib/pngminus/pnm2png.c
@@ -425,7 +425,8 @@ BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,
  } /* end for row */

  /* prepare the standard PNG structures */
-  png_ptr = png_create_write_struct (PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+  png_ptr = png_create_write_struct (png_get_libpng_ver(NULL), NULL, NULL,
+      NULL);
  if (!png_ptr)
  {
    return FALSE;
--- a/contrib/tools/pngfix.c
+++ b/contrib/tools/pngfix.c
@@ -2,14 +2,14 @@
 *
 * Copyright (c) 2014 John Cunningham Bowler
 *
- * Last changed in libpng 1.6.14 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.14 [October 23, 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>
@@ -3580,7 +3580,7 @@ read_png(struct control *control)
   volatile png_bytep row = NULL, display = NULL;
   volatile int rc;

-   png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, control,
+   png_ptr = png_create_read_struct(png_get_libpng_ver(NULL), control,
      error_handler, warning_handler);

   if (png_ptr == NULL)
--- a/contrib/visupng/PngFile.c
+++ b/contrib/visupng/PngFile.c
@@ -136,7 +136,7 @@ BOOL PngLoadImage (PTSTR pstrFileName, png_byte **ppbImageData,

    /* create the two png(-info) structures */

-    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL,
+    png_ptr = png_create_read_struct(png_get_libpng_ver(NULL), NULL,
      (png_error_ptr)png_cexcept_error, (png_error_ptr)NULL);
    if (!png_ptr)
    {
@@ -313,7 +313,7 @@ BOOL PngSaveImage (PTSTR pstrFileName, png_byte *pDiData,

    /* prepare the standard PNG structures */

-    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL,
+    png_ptr = png_create_write_struct(png_get_libpng_ver(NULL), NULL,
      (png_error_ptr)png_cexcept_error, (png_error_ptr)NULL);
    if (!png_ptr)
    {
--- a/example.c
+++ b/example.c
@@ -2,7 +2,7 @@
 #if 0 /* in case someone actually tries to compile this */

 /* example.c - an example of using libpng
- * Last changed in libpng 1.6.11 [June 5, 2014]
+ * Last changed in libpng 1.6.15 [November 20, 2014]
 * Maintained 1998-2014 Glenn Randers-Pehrson
 * Maintained 1996, 1997 Andreas Dilger)
 * Written 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -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]))
+      if (png_image_begin_read_from_file(&image, argv[1]) != 0)
      {
         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/*row_stride*/, NULL/*colormap*/) != 0)
         {
            /* 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*/))
+               buffer, 0/*row_stride*/, NULL/*colormap*/) != 0)
            {
               /* 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 convertion to 16-bit is also
+ * the current libpng implementation of conversion 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 minimise transformations, on the
+ * need to do more complex transformations, or minimize 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))
+   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS) != 0)
      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))
+   if (png_get_bKGD(png_ptr, info_ptr, &image_background) != 0)
      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))
+   if (png_get_sRGB(png_ptr, info_ptr, &intent) != 0)
      png_set_gamma(png_ptr, screen_gamma, PNG_DEFAULT_sRGB);
   else
   {
      double image_gamma;
-      if (png_get_gAMA(png_ptr, info_ptr, &image_gamma))
+      if (png_get_gAMA(png_ptr, info_ptr, &image_gamma) != 0)
         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)
+   if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
   {
      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))
+      else if (png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette) != 0)
      {
         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 /* PNG_READ_QUANTIZE_SUPPORTED */
+#endif /* READ_QUANTIZE */

   /* 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))
+   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT) != 0)
   {
      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)
+   if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
      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 /* PNG_READ_INTERLACING_SUPPORTED */
+#endif /* READ_INTERLACING */


   /* 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 /* PNG_READ_INTERLACING_SUPPORTED */
+#endif /* READ_INTERLACING */
 }

 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
-    * chunks gets changed to PNG_TEXT_COMPRESSION_NONE_WR or
+    * chunk 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
@@ -1,6 +1,6 @@
 libpng-manual.txt - A description on how to use and modify libpng

- libpng version 1.6.14beta06 - October 5, 2014
+ libpng version 1.6.16 - December 22, 2014
 Updated and distributed by Glenn Randers-Pehrson
 <glennrp at users.sourceforge.net>
 Copyright (c) 1998-2014 Glenn Randers-Pehrson
@@ -11,7 +11,7 @@ libpng-manual.txt - A description on how to use and modify libpng

 Based on:

- libpng versions 0.97, January 1998, through 1.6.14beta06 - October 5, 2014
+ libpng versions 0.97, January 1998, through 1.6.16 - December 22, 2014
 Updated and distributed by Glenn Randers-Pehrson
 Copyright (c) 1998-2014 Glenn Randers-Pehrson

@@ -648,15 +648,12 @@ 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-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
+you wish to reduce these limits, you can use

   png_set_user_limits(png_ptr, width_max, height_max);

-to set your own limits, or use width_max = height_max = 0x7fffffffL
-to allow all valid dimensions (libpng may reject some very large images
+to set your own limits (libpng may reject some very wide images
 anyway because of potential buffer overflow conditions).

 You should put this statement after you create the PNG structure and
@@ -3261,7 +3258,7 @@ tEXt chunk use RFC 1123 format dates (e.g. "22 May 1997 18:07:10 GMT"),
 although this isn't a requirement.  Unlike the tIME chunk, the
 "Creation Time" tEXt chunk is not expected to be automatically changed
 by the software.  To facilitate the use of RFC 1123 dates, a function
-png_convert_to_rfc1123_buffer(png_ptr, buffer, png_timep) is provided to
+png_convert_to_rfc1123_buffer(buffer, png_timep) is provided to
 convert from PNG time to an RFC 1123 format string.  The caller must provide
 a writeable buffer of at least 29 bytes.

@@ -5037,8 +5034,8 @@ 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

@@ -5048,8 +5045,8 @@ means of
           PNG_OPTION_ON);
    #endif

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

 The PNG spec requirement that only grayscale profiles may appear in images
@@ -5277,13 +5274,13 @@ Other rules can be inferred by inspecting the libpng source.

 XVI. Y2K Compliance in libpng

-October 5, 2014
+December 22, 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 1.6.14beta06 are Y2K compliant.  It is my belief that earlier
+upward through 1.6.16 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
@@ -5299,8 +5296,9 @@ in libpng-1.6.x and will be removed from libpng-1.7.0.

 There are seven time-related functions:

-    png_convert_to_rfc_1123() in png.c
-      (formerly png_convert_to_rfc_1152() in error)
+    png_convert_to_rfc_1123_buffer() in png.c
+      (formerly png_convert_to_rfc_1152() in error, and
+      also formerly png_convert_to_rfc_1123())
    png_convert_from_struct_tm() in pngwrite.c, called
      in pngwrite.c
    png_convert_from_time_t() in pngwrite.c
--- a/libpng.3
+++ b/libpng.3
@@ -1,6 +1,6 @@
-.TH LIBPNG 3 "October 5, 2014"
+.TH LIBPNG 3 "December 22, 2014"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.6.14beta06
+libpng \- Portable Network Graphics (PNG) Reference Library 1.6.16
 .SH SYNOPSIS
 \fB
 #include <png.h>\fP
@@ -504,7 +504,7 @@ 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 1.6.14beta06 - October 5, 2014
+ libpng version 1.6.16 - December 22, 2014
 Updated and distributed by Glenn Randers-Pehrson
 <glennrp at users.sourceforge.net>
 Copyright (c) 1998-2014 Glenn Randers-Pehrson
@@ -515,7 +515,7 @@ libpng-manual.txt - A description on how to use and modify libpng

 Based on:

- libpng versions 0.97, January 1998, through 1.6.14beta06 - October 5, 2014
+ libpng versions 0.97, January 1998, through 1.6.16 - December 22, 2014
 Updated and distributed by Glenn Randers-Pehrson
 Copyright (c) 1998-2014 Glenn Randers-Pehrson

@@ -1152,15 +1152,12 @@ 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-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
+you wish to reduce these limits, you can use

   png_set_user_limits(png_ptr, width_max, height_max);

-to set your own limits, or use width_max = height_max = 0x7fffffffL
-to allow all valid dimensions (libpng may reject some very large images
+to set your own limits (libpng may reject some very wide images
 anyway because of potential buffer overflow conditions).

 You should put this statement after you create the PNG structure and
@@ -3765,7 +3762,7 @@ tEXt chunk use RFC 1123 format dates (e.g. "22 May 1997 18:07:10 GMT"),
 although this isn't a requirement.  Unlike the tIME chunk, the
 "Creation Time" tEXt chunk is not expected to be automatically changed
 by the software.  To facilitate the use of RFC 1123 dates, a function
-png_convert_to_rfc1123_buffer(png_ptr, buffer, png_timep) is provided to
+png_convert_to_rfc1123_buffer(buffer, png_timep) is provided to
 convert from PNG time to an RFC 1123 format string.  The caller must provide
 a writeable buffer of at least 29 bytes.

@@ -5541,8 +5538,8 @@ 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

@@ -5552,8 +5549,8 @@ means of
           PNG_OPTION_ON);
    #endif

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

 The PNG spec requirement that only grayscale profiles may appear in images
@@ -5781,13 +5778,13 @@ Other rules can be inferred by inspecting the libpng source.

 .SH XVI. Y2K Compliance in libpng

-October 5, 2014
+December 22, 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 1.6.14beta06 are Y2K compliant.  It is my belief that earlier
+upward through 1.6.16 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
@@ -5803,8 +5800,9 @@ in libpng-1.6.x and will be removed from libpng-1.7.0.

 There are seven time-related functions:

-    png_convert_to_rfc_1123() in png.c
-      (formerly png_convert_to_rfc_1152() in error)
+    png_convert_to_rfc_1123_buffer() in png.c
+      (formerly png_convert_to_rfc_1152() in error, and
+      also formerly png_convert_to_rfc_1123())
    png_convert_from_struct_tm() in pngwrite.c, called
      in pngwrite.c
    png_convert_from_time_t() in pngwrite.c
@@ -6029,7 +6027,15 @@ the first widely used release:
 1.6.13beta01-04     16    10613  16.so.16.13[.0]
 1.6.13rc01-02       16    10613  16.so.16.13[.0]
 1.6.13              16    10613  16.so.16.13[.0]
- 1.6.14beta01-06     16    10614  16.so.16.14[.0]
+ 1.6.14beta01-07     16    10614  16.so.16.14[.0]
+ 1.6.14rc01-02       16    10614  16.so.16.14[.0]
+ 1.6.14              16    10614  16.so.16.14[.0]
+ 1.6.15beta01-08     16    10615  16.so.16.15[.0]
+ 1.6.15rc01-03       16    10615  16.so.16.15[.0]
+ 1.6.15              16    10615  16.so.16.15[.0]
+ 1.6.16beta01-03     16    10616  16.so.16.16[.0]
+ 1.6.16rc01-02       16    10616  16.so.16.16[.0]
+ 1.6.16              16    10616  16.so.16.16[.0]

 Henceforth the source version will match the shared-library minor
 and patch numbers; the shared-library major version number will be
@@ -6086,7 +6092,7 @@ possible without all of you.

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

-Libpng version 1.6.14beta06 - October 5, 2014:
+Libpng version 1.6.16 - December 22, 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).

@@ -6109,7 +6115,7 @@ this sentence.

 This code is released under the libpng license.

-libpng versions 1.2.6, August 15, 2004, through 1.6.14beta06, October 5, 2014, are
+libpng versions 1.2.6, August 15, 2004, through 1.6.16, December 22, 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
@@ -6208,7 +6214,7 @@ certification mark of the Open Source Initiative.

 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-October 5, 2014
+December 22, 2014

 .\" end of man page

--- a/libpngpf.3
+++ b/libpngpf.3
@@ -1,6 +1,6 @@
-.TH LIBPNGPF 3 "October 5, 2014"
+.TH LIBPNGPF 3 "December 22, 2014"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.6.14beta06
+libpng \- Portable Network Graphics (PNG) Reference Library 1.6.16
 (private functions)
 .SH SYNOPSIS
 \fB#include \fI"pngpriv.h"
--- a/png.5
+++ b/png.5
@@ -1,4 +1,4 @@
-.TH PNG 5 "October 5, 2014"
+.TH PNG 5 "December 22, 2014"
 .SH NAME
 png \- Portable Network Graphics (PNG) format
 .SH DESCRIPTION
--- a/png.c
+++ b/png.c
--- a/png.h
+++ b/png.h
@@ -1,7 +1,7 @@

 /* png.h - header file for PNG reference library
 *
- * libpng version 1.6.14beta06 - October 5, 2014
+ * libpng version 1.6.16, December 22, 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 1.6.14beta06 - October 5, 2014: Glenn
+ *   libpng versions 0.97, January 1998, through 1.6.16, December 22, 2014: Glenn
 *   See also "Contributing Authors", below.
 *
 * Note about libpng version numbers:
@@ -203,7 +203,15 @@
 *    1.6.13beta01-04         16    10613  16.so.16.13[.0]
 *    1.6.13rc01-02           16    10613  16.so.16.13[.0]
 *    1.6.13                  16    10613  16.so.16.13[.0]
- *    1.6.14beta01-06         16    10614  16.so.16.14[.0]
+ *    1.6.14beta01-07         16    10614  16.so.16.14[.0]
+ *    1.6.14rc01-02           16    10614  16.so.16.14[.0]
+ *    1.6.14                  16    10614  16.so.16.14[.0]
+ *    1.6.15beta01-08         16    10615  16.so.16.15[.0]
+ *    1.6.15rc01-03           16    10615  16.so.16.15[.0]
+ *    1.6.15                  16    10615  16.so.16.15[.0]
+ *    1.6.16beta01-03         16    10616  16.so.16.16[.0]
+ *    1.6.16rc01-02           16    10616  16.so.16.16[.0]
+ *    1.6.16                  16    10616  16.so.16.16[.0]
 *
 *   Henceforth the source version will match the shared-library major
 *   and minor numbers; the shared-library major version number will be
@@ -235,7 +243,7 @@
 *
 * This code is released under the libpng license.
 *
- * libpng versions 1.2.6, August 15, 2004, through 1.6.14beta06, October 5, 2014, are
+ * libpng versions 1.2.6, August 15, 2004, through 1.6.16, December 22, 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:
@@ -347,13 +355,13 @@
 * Y2K compliance in libpng:
 * =========================
 *
- *    October 5, 2014
+ *    December 22, 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 1.6.14beta06 are Y2K compliant.  It is my belief that
+ *    upward through 1.6.16 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
@@ -415,9 +423,9 @@
 */

 /* Version information for png.h - this should match the version in png.c */
-#define PNG_LIBPNG_VER_STRING "1.6.14beta06"
+#define PNG_LIBPNG_VER_STRING "1.6.16"
 #define PNG_HEADER_VERSION_STRING \
-     " libpng version 1.6.14beta06 - October 5, 2014\n"
+     " libpng version 1.6.16 - December 22, 2014\n"

 #define PNG_LIBPNG_VER_SONUM   16
 #define PNG_LIBPNG_VER_DLLNUM  16
@@ -425,13 +433,13 @@
 /* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
 #define PNG_LIBPNG_VER_MAJOR   1
 #define PNG_LIBPNG_VER_MINOR   6
-#define PNG_LIBPNG_VER_RELEASE 14
+#define PNG_LIBPNG_VER_RELEASE 16

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

-#define PNG_LIBPNG_VER_BUILD  06
+#define PNG_LIBPNG_VER_BUILD  0

 /* Release Status */
 #define PNG_LIBPNG_BUILD_ALPHA    1
@@ -448,7 +456,7 @@
 #define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
                                       PNG_LIBPNG_BUILD_PRIVATE */

-#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_BETA
+#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_STABLE

 /* Careful here.  At one time, Guy wanted to use 082, but that would be octal.
 * We must not include leading zeros.
@@ -456,7 +464,7 @@
 * 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 10614 /* 1.6.14 */
+#define PNG_LIBPNG_VER 10616 /* 1.6.16 */

 /* Library configuration: these options cannot be changed after
 * the library has been built.
@@ -561,7 +569,7 @@ 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_6_14beta06;
+typedef char* png_libpng_version_1_6_16;

 /* Basic control structions.  Read libpng-manual.txt or libpng.3 for more info.
 *
@@ -1174,7 +1182,7 @@ 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 /* PNG_CONVERT_tIME_SUPPORTED */
+#endif /* CONVERT_tIME */

 #ifdef PNG_READ_EXPAND_SUPPORTED
 /* Expand data to 24-bit RGB, or 8-bit grayscale, with alpha if available. */
@@ -1380,7 +1388,7 @@ 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 /* PNG_READ_FILLER_SUPPORTED || PNG_WRITE_FILLER_SUPPORTED */
+#endif /* READ_FILLER || WRITE_FILLER */

 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
 /* Swap bytes in 16-bit depth files. */
@@ -1644,7 +1652,7 @@ 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 /*  PNG_WRITE_WEIGHTED_FILTER_SUPPORTED */
+#endif /* WRITE_WEIGHTED_FILTER */

 /* Heuristic used for row filter selection.  These defines should NOT be
 * changed.
@@ -1700,7 +1708,7 @@ 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 /* PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED */
+#endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */

 /* These next functions are called for input/output, memory, and error
 * handling.  They are in the file pngrio.c, pngwio.c, and pngerror.c,
@@ -1867,7 +1875,7 @@ 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 /* PNG_PROGRESSIVE_READ_SUPPORTED */
+#endif /* PROGRESSIVE_READ */

 PNG_EXPORTA(94, png_voidp, png_malloc, (png_const_structrp png_ptr,
    png_alloc_size_t size), PNG_ALLOCATED);
@@ -2068,7 +2076,7 @@ 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 /* PNG_EASY_ACCESS_SUPPORTED */
+#endif /* EASY_ACCESS */

 #ifdef PNG_READ_SUPPORTED
 /* Returns pointer to signature string read from PNG header */
@@ -2320,7 +2328,7 @@ PNG_FIXED_EXPORT(213, void, png_set_sCAL_fixed, (png_const_structrp png_ptr,
 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 /* PNG_sCAL_SUPPORTED */
+#endif /* sCAL */

 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
 /* Provide the default handling for all unknown chunks or, optionally, for
@@ -2548,8 +2556,8 @@ 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 /* PNG_pHYs_SUPPORTED */
-#endif  /* PNG_INCH_CONVERSIONS_SUPPORTED */
+#  endif /* pHYs */
+#endif  /* INCH_CONVERSIONS */

 /* Added in libpng-1.4.0 */
 #ifdef PNG_IO_STATE_SUPPORTED
@@ -2572,7 +2580,7 @@ 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 /* ?PNG_IO_STATE_SUPPORTED */
+#endif /* IO_STATE */

 /* Interlace support.  The following macros are always defined so that if
 * libpng interlace handling is turned off the macros may be used to handle
@@ -2676,7 +2684,7 @@ 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 /* PNG_READ_COMPOSITE_NODIV_SUPPORTED */
+#endif /* READ_COMPOSITE_NODIV */

 #ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
 PNG_EXPORT(201, png_uint_32, png_get_uint_32, (png_const_bytep buf));
@@ -3104,7 +3112,7 @@ 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 /* PNG_STDIO_SUPPORTED */
+#endif /* STDIO */

 PNG_EXPORT(236, int, png_image_begin_read_from_memory, (png_imagep image,
   png_const_voidp memory, png_size_t size));
@@ -3149,7 +3157,7 @@ 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 /* PNG_SIMPLIFIED_READ_SUPPORTED */
+#endif /* SIMPLIFIED_READ */

 #ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
 #ifdef PNG_STDIO_SUPPORTED
@@ -3195,12 +3203,12 @@ 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 /* PNG_STDIO_SUPPORTED */
-#endif /* PNG_SIMPLIFIED_WRITE_SUPPORTED */
+#endif /* STDIO */
+#endif /* SIMPLIFIED_WRITE */
 /*******************************************************************************
 *  END OF SIMPLIFIED API
 ******************************************************************************/
-#endif /* PNG_SIMPLIFIED_{READ|WRITE}_SUPPORTED */
+#endif /* SIMPLIFIED_{READ|WRITE} */

 #ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
 PNG_EXPORT(242, void, png_set_check_for_invalid_index,
@@ -3248,7 +3256,7 @@ PNG_EXPORT(243, int, png_get_palette_max, (png_const_structp png_ptr,

 PNG_EXPORT(244, int, png_set_option, (png_structrp png_ptr, int option,
   int onoff));
-#endif /* PNG_SET_OPTION_SUPPORTED */
+#endif /* SET_OPTION */

 /*******************************************************************************
 *  END OF HARDWARE AND SOFTWARE OPTIONS
--- a/pngconf.h
+++ b/pngconf.h
@@ -1,7 +1,7 @@

 /* pngconf.h - machine configurable file for libpng
 *
- * libpng version 1.6.14beta06 - October 5, 2014
+ * libpng version 1.6.16,December 22, 2014
 *
 * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
--- a/pngerror.c
+++ b/pngerror.c
@@ -1,7 +1,7 @@

 /* pngerror.c - stub functions for i/o and memory allocation
 *
- * Last changed in libpng 1.6.13 [August 21, 2014]
+ * Last changed in libpng 1.6.15 [November 20, 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.)
@@ -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 /* PNG_WARNINGS_SUPPORTED */
+#endif /* WARNINGS */

 /* 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))
+      if ((png_ptr->flags &
+         (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT)) != 0
      {
         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)
+            if ((png_ptr->flags & PNG_FLAG_STRIP_ERROR_TEXT) != 0)
            {
               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)
+         if ((png_ptr->flags & PNG_FLAG_STRIP_ERROR_TEXT) != 0)
         {
            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 /* PNG_ERROR_TEXT_SUPPORTED */
+#endif /* ERROR_TEXT */

 /* 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 || number % 10 != 0)
+            if (output != 0 || 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) if (count == 5) if (end > start)
+      if ((format == PNG_NUMBER_FORMAT_fixed) && (count == 5) && (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))
+   if ((png_ptr->flags &
+       (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT)) != 0)
 #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 /* PNG_WARNINGS_SUPPORTED */
+#endif /* WARNINGS */

 #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)
+   if ((png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN) != 0)
   {
 #     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)
+  if ((png_ptr->flags & PNG_FLAG_APP_WARNINGS_WARN) != 0)
     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)
+  if ((png_ptr->flags & PNG_FLAG_APP_ERRORS_WARN) != 0)
     png_warning(png_ptr, error_message);
  else
     png_error(png_ptr, error_message);
@@ -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))
+      if (isnonalpha(c) != 0)
      {
         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 /* PNG_WARNINGS_SUPPORTED || PNG_ERROR_TEXT_SUPPORTED */
+#endif /* WARNINGS || ERROR_TEXT */

 #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 /* PNG_READ_SUPPORTED && PNG_ERROR_TEXT_SUPPORTED */
+#endif /* READ && ERROR_TEXT */

 #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 /* PNG_WARNINGS_SUPPORTED */
+#endif /* WARNINGS */

 #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)
+   if ((png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN) != 0)
      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 /* PNG_READ_SUPPORTED */
+#endif /* READ */

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

 #  ifdef PNG_WRITE_SUPPORTED
@@ -577,11 +577,12 @@ 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);
 }
@@ -757,7 +758,8 @@ PNG_FUNCTION(void,PNGAPI
 png_longjmp,(png_const_structrp png_ptr, int val),PNG_NORETURN)
 {
 #ifdef PNG_SETJMP_SUPPORTED
-   if (png_ptr && png_ptr->longjmp_fn && png_ptr->jmp_buf_ptr)
+   if (png_ptr != NULL && png_ptr->longjmp_fn != NULL &&
+       png_ptr->jmp_buf_ptr != NULL)
      png_ptr->longjmp_fn(*png_ptr->jmp_buf_ptr, val);
 #else
   PNG_UNUSED(png_ptr)
@@ -822,7 +824,7 @@ png_default_warning(png_const_structrp png_ptr, png_const_charp warning_message)
 #endif
   PNG_UNUSED(png_ptr) /* Make compiler happy */
 }
-#endif /* PNG_WARNINGS_SUPPORTED */
+#endif /* WARNINGS */

 /* This function is called when the application wants to use another method
 * of handling errors and warnings.  Note that the error function MUST NOT
@@ -957,5 +959,5 @@ png_safe_execute(png_imagep image_in, int (*function)(png_voidp), png_voidp arg)

   return result;
 }
-#endif /* SIMPLIFIED READ/WRITE */
-#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
+#endif /* SIMPLIFIED READ || SIMPLIFIED_WRITE */
+#endif /* READ || WRITE */
--- a/pngget.c
+++ b/pngget.c
@@ -1,7 +1,7 @@

 /* pngget.c - retrieval of values from info struct
 *
- * Last changed in libpng 1.6.11 [June 5, 2014]
+ * Last changed in libpng 1.6.15 [November 20, 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.)
@@ -116,7 +116,8 @@ 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))
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pHYs) != 0)
      {
         png_debug1(1, "in %s retrieval function",
             "png_get_x_pixels_per_meter");
@@ -137,7 +138,8 @@ 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))
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pHYs) != 0)
   {
      png_debug1(1, "in %s retrieval function",
          "png_get_y_pixels_per_meter");
@@ -157,7 +159,8 @@ 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))
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pHYs) != 0)
   {
      png_debug1(1, "in %s retrieval function", "png_get_pixels_per_meter");

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

@@ -202,10 +206,11 @@ 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)
-       && 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) != 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)
   {
      png_fixed_point res;

@@ -215,7 +220,7 @@ 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))
+          (png_int_32)info_ptr->x_pixels_per_unit) != 0)
         return res;
   }
 #else
@@ -231,7 +236,8 @@ 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))
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_oFFs) != 0)
   {
      png_debug1(1, "in %s retrieval function", "png_get_x_offset_microns");

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

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

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

@@ -328,7 +337,7 @@ 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))
+       5000) != 0)
      return result;

   /* Overflow. */
@@ -414,7 +423,8 @@ 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))
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pHYs) != 0)
   {
      png_debug1(1, "in %s retrieval function", "pHYs");

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

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

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

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


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

@@ -509,7 +520,7 @@ 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))
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
   {
      png_debug1(1, "in %s retrieval function", "cHRM");

@@ -550,7 +561,7 @@ 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))
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
   {
      png_debug1(1, "in %s retrieval function", "cHRM_XYZ(float)");

@@ -598,7 +609,7 @@ 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))
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
   {
      png_debug1(1, "in %s retrieval function", "cHRM_XYZ");

@@ -635,7 +646,7 @@ 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))
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
   {
      if (white_x != NULL)
         *white_x = info_ptr->colorspace.end_points_xy.whitex;
@@ -670,7 +681,7 @@ 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) &&
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) != 0 &&
      file_gamma != NULL)
   {
      *file_gamma = info_ptr->colorspace.gamma;
@@ -689,7 +700,7 @@ 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) &&
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) != 0 &&
      file_gamma != NULL)
   {
      *file_gamma = png_float(png_ptr, info_ptr->colorspace.gamma,
@@ -709,8 +720,8 @@ 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)
-       && file_srgb_intent != NULL)
+   if (png_ptr != NULL && info_ptr != NULL &&
+      (info_ptr->valid & PNG_INFO_sRGB) != 0 && file_srgb_intent != NULL)
   {
      *file_srgb_intent = info_ptr->colorspace.rendering_intent;
      return (PNG_INFO_sRGB);
@@ -728,9 +739,10 @@ 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)
-       && name != NULL && compression_type != NULL && profile != NULL &&
-		 proflen != NULL)
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_iCCP) != 0 &&
+       name != NULL && compression_type != NULL && profile != NULL &&
+           proflen != NULL)
   {
      *name = info_ptr->iccp_name;
      *profile = info_ptr->iccp_profile;
@@ -768,8 +780,8 @@ 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)
-       && hist != NULL)
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_hIST) != 0 && hist != NULL)
   {
      *hist = info_ptr->hist;
      return (PNG_INFO_hIST);
@@ -824,8 +836,9 @@ 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)
-       && offset_x != NULL && offset_y != NULL && unit_type != NULL)
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_oFFs) != 0 &&
+       offset_x != NULL && offset_y != NULL && unit_type != NULL)
   {
      *offset_x = info_ptr->x_offset;
      *offset_y = info_ptr->y_offset;
@@ -845,8 +858,9 @@ 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)
-       && purpose != NULL && X0 != NULL && X1 != NULL && type != NULL &&
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pCAL) != 0 &&
+       purpose != NULL && X0 != NULL && X1 != NULL && type != NULL &&
       nparams != NULL && units != NULL && params != NULL)
   {
      *purpose = info_ptr->pcal_purpose;
@@ -872,7 +886,7 @@ 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))
+       (info_ptr->valid & PNG_INFO_sCAL) != 0)
   {
      *unit = info_ptr->scal_unit;
      /*TODO: make this work without FP support; the API is currently eliminated
@@ -895,7 +909,7 @@ 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))
+       (info_ptr->valid & PNG_INFO_sCAL) != 0)
   {
      *unit = info_ptr->scal_unit;
      *width = atof(info_ptr->scal_s_width);
@@ -911,7 +925,7 @@ 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))
+       (info_ptr->valid & PNG_INFO_sCAL) != 0)
   {
      *unit = info_ptr->scal_unit;
      *width = info_ptr->scal_s_width;
@@ -933,7 +947,7 @@ 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))
+       (info_ptr->valid & PNG_INFO_pHYs) != 0)
   {
      if (res_x != NULL)
      {
@@ -964,8 +978,8 @@ 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)
-       && palette != NULL)
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_PLTE) != 0 && palette != NULL)
   {
      *palette = info_ptr->palette;
      *num_palette = info_ptr->num_palette;
@@ -983,8 +997,8 @@ 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)
-       && sig_bit != NULL)
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_sBIT) != 0 && sig_bit != NULL)
   {
      *sig_bit = &(info_ptr->sig_bit);
      return (PNG_INFO_sBIT);
@@ -1027,8 +1041,8 @@ 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)
-       && mod_time != NULL)
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_tIME) != 0 && mod_time != NULL)
   {
      *mod_time = &(info_ptr->mod_time);
      return (PNG_INFO_tIME);
@@ -1044,7 +1058,8 @@ 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))
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_tRNS) != 0)
   {
      png_debug1(1, "in %s retrieval function", "tRNS");

@@ -1121,7 +1136,7 @@ png_get_compression_buffer_size(png_const_structrp png_ptr)
      return 0;

 #  ifdef PNG_WRITE_SUPPORTED
-      if (png_ptr->mode & PNG_IS_READ_STRUCT)
+      if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
 #  endif
   {
 #     ifdef PNG_SEQUENTIAL_READ_SUPPORTED
@@ -1165,7 +1180,7 @@ png_get_chunk_malloc_max (png_const_structrp png_ptr)
 {
   return (png_ptr ? png_ptr->user_chunk_malloc_max : 0);
 }
-#endif /* ?PNG_SET_USER_LIMITS_SUPPORTED */
+#endif /* SET_USER_LIMITS */

 /* These functions were added to libpng 1.4.0 */
 #ifdef PNG_IO_STATE_SUPPORTED
@@ -1180,7 +1195,7 @@ png_get_io_chunk_type (png_const_structrp png_ptr)
 {
   return png_ptr->chunk_name;
 }
-#endif /* ?PNG_IO_STATE_SUPPORTED */
+#endif /* IO_STATE */

 #ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
 #  ifdef PNG_GET_PALETTE_MAX_SUPPORTED
@@ -1195,4 +1210,4 @@ png_get_palette_max(png_const_structp png_ptr, png_const_infop info_ptr)
 #  endif
 #endif

-#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
+#endif /* READ || WRITE */
--- a/pnginfo.h
+++ b/pnginfo.h
@@ -121,7 +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 /* PNG_TEXT_SUPPORTED */
+#endif /* TEXT */

 #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 1.6.8 [December 19, 2013]
- * Copyright (c) 1998-2013 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.15 [November 20, 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.)
 *
@@ -199,7 +199,7 @@ png_malloc_default,(png_const_structrp png_ptr, png_alloc_size_t size),

   return ret;
 }
-#endif /* PNG_USER_MEM_SUPPORTED */
+#endif /* USER_MEM */

 /* 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
@@ -244,7 +244,7 @@ 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 */
+#endif /* USER_MEM */

   free(ptr);
 }
@@ -277,5 +277,5 @@ png_get_mem_ptr(png_const_structrp png_ptr)

   return png_ptr->mem_ptr;
 }
-#endif /* PNG_USER_MEM_SUPPORTED */
-#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
+#endif /* USER_MEM */
+#endif /* READ || WRITE */
--- a/pngpread.c
+++ b/pngpread.c
@@ -1,7 +1,7 @@

 /* pngpread.c - read a png file in push mode
 *
- * Last changed in libpng 1.6.14 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.15 [November 20, 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.)
@@ -29,7 +29,7 @@
 #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(N) \
+#define PNG_PUSH_SAVE_BUFFER_IF_LT(N) \
 if (png_ptr->buffer_size < N) \
   { png_push_save_buffer(png_ptr); return; }

@@ -202,12 +202,12 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
    * 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))
+   if ((png_ptr->mode & PNG_HAVE_CHUNK_HEADER) == 0)
   {
      png_byte chunk_length[4];
      png_byte chunk_tag[4];

-      PNG_PUSH_SAVE_BUFFER_IF_LT_N(8)
+      PNG_PUSH_SAVE_BUFFER_IF_LT(8)
      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);
@@ -221,28 +221,28 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)

   if (chunk_name == png_IDAT)
   {
-      if (png_ptr->mode & PNG_AFTER_IDAT)
+      if ((png_ptr->mode & PNG_AFTER_IDAT) != 0)
         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))
+      if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
         png_error(png_ptr, "Missing IHDR before IDAT");

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

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

@@ -449,7 +449,7 @@ 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 && png_ptr->save_buffer_size)
+   if (png_ptr->skip_length != 0 && png_ptr->save_buffer_size != 0)
   {
      png_size_t save_size = png_ptr->save_buffer_size;
      png_uint_32 skip_length = png_ptr->skip_length;
@@ -473,7 +473,7 @@ 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 && png_ptr->current_buffer_size)
+   if (png_ptr->skip_length != 0 && png_ptr->current_buffer_size != 0)
   {
      png_size_t save_size = png_ptr->current_buffer_size;
      png_uint_32 skip_length = png_ptr->skip_length;
@@ -494,9 +494,9 @@ 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)
+   if (png_ptr->skip_length == 0)
   {
-      PNG_PUSH_SAVE_BUFFER_IF_LT_N(4)
+      PNG_PUSH_SAVE_BUFFER_IF_LT(4)
      png_crc_finish(png_ptr, 0);
      png_ptr->process_mode = PNG_READ_CHUNK_MODE;
   }
@@ -511,7 +511,7 @@ png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
      return;

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

@@ -528,7 +528,7 @@ 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 && png_ptr->current_buffer_size)
+   if (length != 0 && png_ptr->current_buffer_size != 0)
   {
      png_size_t save_size;

@@ -548,7 +548,7 @@ 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)
+   if (png_ptr->save_buffer_size != 0)
   {
      if (png_ptr->save_buffer_ptr != png_ptr->save_buffer)
      {
@@ -584,11 +584,13 @@ 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)
@@ -615,13 +617,13 @@ 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))
+   if ((png_ptr->mode & PNG_HAVE_CHUNK_HEADER) == 0)
   {
      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_N(8)
+      PNG_PUSH_SAVE_BUFFER_IF_LT(8)
      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);
@@ -633,7 +635,7 @@ png_push_read_IDAT(png_structrp png_ptr)
      {
         png_ptr->process_mode = PNG_READ_CHUNK_MODE;

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

         return;
@@ -642,7 +644,7 @@ png_push_read_IDAT(png_structrp png_ptr)
      png_ptr->idat_size = png_ptr->push_length;
   }

-   if (png_ptr->idat_size && png_ptr->save_buffer_size)
+   if (png_ptr->idat_size != 0 && png_ptr->save_buffer_size != 0)
   {
      png_size_t save_size = png_ptr->save_buffer_size;
      png_uint_32 idat_size = png_ptr->idat_size;
@@ -669,7 +671,7 @@ png_push_read_IDAT(png_structrp png_ptr)
      png_ptr->save_buffer_ptr += save_size;
   }

-   if (png_ptr->idat_size && png_ptr->current_buffer_size)
+   if (png_ptr->idat_size != 0 && png_ptr->current_buffer_size != 0)
   {
      png_size_t save_size = png_ptr->current_buffer_size;
      png_uint_32 idat_size = png_ptr->idat_size;
@@ -694,9 +696,9 @@ 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)
+   if (png_ptr->idat_size == 0)
   {
-      PNG_PUSH_SAVE_BUFFER_IF_LT_N(4)
+      PNG_PUSH_SAVE_BUFFER_IF_LT(4)
      png_crc_finish(png_ptr, 0);
      png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
      png_ptr->mode |= PNG_AFTER_IDAT;
@@ -841,7 +843,7 @@ 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)
+   if (png_ptr->transformations != 0)
      png_do_read_transformations(png_ptr, &row_info);
 #endif

@@ -859,7 +861,8 @@ png_push_process_row(png_structrp png_ptr)

 #ifdef PNG_READ_INTERLACING_SUPPORTED
   /* Expand interlaced rows to full size */
-   if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
+   if (png_ptr->interlaced != 0 &&
+       (png_ptr->transformations & PNG_INTERLACE) != 0)
   {
      if (png_ptr->pass < 6)
         png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
@@ -1066,7 +1069,7 @@ png_read_push_finish_row(png_structrp png_ptr)
   if (png_ptr->row_number < png_ptr->num_rows)
      return;

-   if (png_ptr->interlaced)
+   if (png_ptr->interlaced != 0)
   {
      png_ptr->row_number = 0;
      memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
@@ -1090,7 +1093,7 @@ 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)
+         if ((png_ptr->transformations & PNG_INTERLACE) != 0)
            break;

         png_ptr->num_rows = (png_ptr->height +
@@ -1162,4 +1165,4 @@ png_get_progressive_ptr(png_const_structrp png_ptr)

   return png_ptr->io_ptr;
 }
-#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
+#endif /* PROGRESSIVE_READ */
--- a/pngpriv.h
+++ b/pngpriv.h
@@ -172,7 +172,7 @@
          */
 #        define PNG_ARM_NEON_IMPLEMENTATION 2
 #     endif /* __ARM_NEON__ */
-#  endif /* !defined PNG_ARM_NEON_IMPLEMENTATION */
+#  endif /* !PNG_ARM_NEON_IMPLEMENTATION */

 #  ifndef PNG_ARM_NEON_IMPLEMENTATION
      /* Use the intrinsics code by default. */
@@ -855,7 +855,7 @@ PNG_INTERNAL_DATA(const png_byte, png_sRGB_delta, [512]);
   /* 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 */
+#endif /* SIMPLIFIED_READ/WRITE */


 /* Inhibit C++ name-mangling for libpng functions but not for system calls. */
@@ -1229,7 +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 /* PNG_SEQUENTIAL_READ_SUPPORTED */
+#endif /* SEQUENTIAL_READ */

 /* Initialize the row buffers, etc. */
 PNG_INTERNAL_FUNCTION(void,png_read_start_row,(png_structrp png_ptr),PNG_EMPTY);
@@ -1305,7 +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 /* PNG_READ_iCCP_SUPPORTED */
+#endif /* READ_iCCP */

 #ifdef PNG_READ_iTXt_SUPPORTED
 PNG_INTERNAL_FUNCTION(void,png_handle_iTXt,(png_structrp png_ptr,
@@ -1340,7 +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 /* PNG_READ_sPLT_SUPPORTED */
+#endif /* READ_sPLT */

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

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

 /* Added at libpng version 1.6.0 */
 #ifdef PNG_GAMMA_SUPPORTED
--- a/pngread.c
+++ b/pngread.c
@@ -1,7 +1,7 @@

 /* pngread.c - read a PNG file
 *
- * Last changed in libpng 1.6.11 [June 5, 2014]
+ * Last changed in libpng 1.6.15 [November 20, 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 /* PNG_USER_MEM_SUPPORTED */
+#endif /* USER_MEM */

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

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

         png_ptr->mode |= PNG_HAVE_IDAT;
      }

-      else if (png_ptr->mode & PNG_HAVE_IDAT)
+      else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
         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 /* PNG_SEQUENTIAL_READ_SUPPORTED */
+#endif /* SEQUENTIAL_READ */

 /* 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 /* PNG_SEQUENTIAL_READ_SUPPORTED */
+#endif /* SEQUENTIAL_READ */

 #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))
+       (row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
   {
      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 /* PNG_MNG_FEATURES_SUPPORTED */
+#endif /* MNG_FEATURES */

 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))
+   if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
      png_read_start_row(png_ptr);

   /* 1.5.6: row_info moved out of png_struct to a local here. */
@@ -396,45 +396,47 @@ 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)
+   if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
      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)
+   if ((png_ptr->transformations & PNG_FILLER) != 0)
      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)
+   if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
      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)
+   if ((png_ptr->transformations & PNG_PACK) != 0)
      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)
+   if ((png_ptr->transformations & PNG_SHIFT) != 0)
      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)
+   if ((png_ptr->transformations & PNG_BGR) != 0)
      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)
+   if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
      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.
@@ -443,7 +445,8 @@ 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 && (png_ptr->transformations & PNG_INTERLACE))
+   if (png_ptr->interlaced != 0 &&
+       (png_ptr->transformations & PNG_INTERLACE) != 0)
   {
      switch (png_ptr->pass)
      {
@@ -514,7 +517,7 @@ png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row)

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

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

   /* Fill the row with IDAT data: */
@@ -547,7 +550,7 @@ 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) &&
+   if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
       (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
   {
      /* Intrapixel differencing */
@@ -573,8 +576,8 @@ 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 &&
-      (png_ptr->transformations & PNG_INTERLACE))
+   if (png_ptr->interlaced != 0 &&
+      (png_ptr->transformations & PNG_INTERLACE) != 0)
   {
      if (png_ptr->pass < 6)
         png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
@@ -602,7 +605,7 @@ 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 /* PNG_SEQUENTIAL_READ_SUPPORTED */
+#endif /* SEQUENTIAL_READ */

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

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

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

 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
 /* Read the end of the PNG file.  Will not read past the end of the
@@ -765,7 +769,7 @@ 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))
+   if (png_chunk_unknown_handling(png_ptr, png_IDAT) == 0)
 #endif
      png_read_finish_IDAT(png_ptr);

@@ -795,7 +799,8 @@ 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))
+            if ((length > 0) ||
+                (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) != 0)
               png_benign_error(png_ptr, "Too many IDATs found");
         }
         png_handle_unknown(png_ptr, info_ptr, length, keep);
@@ -809,7 +814,8 @@ 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))
+         if ((length > 0) ||
+             (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) != 0)
            png_benign_error(png_ptr, "Too many IDATs found");

         png_crc_finish(png_ptr, length);
@@ -905,9 +911,9 @@ 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));
+   } while ((png_ptr->mode & PNG_HAVE_IEND) == 0);
 }
-#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
+#endif /* SEQUENTIAL_READ */

 /* Free all memory used in the read struct */
 static void
@@ -920,22 +926,33 @@ 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)
+   if ((png_ptr->free_me & PNG_FREE_PLTE) != 0)
+   {
      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)
+   if ((png_ptr->free_me & PNG_FREE_TRNS) != 0)
+   {
      png_free(png_ptr, png_ptr->trans_alpha);
+      png_ptr->trans_alpha = NULL;
+   }
   png_ptr->free_me &= ~PNG_FREE_TRNS;
 #endif

@@ -943,15 +960,18 @@ 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
@@ -1023,7 +1043,7 @@ 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)
+   if ((transforms & PNG_TRANSFORM_SCALE_16) != 0)
     /* 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.
      */
@@ -1037,7 +1057,7 @@ 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)
+   if ((transforms & PNG_TRANSFORM_STRIP_16) != 0)
 #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
      png_set_strip_16(png_ptr);
 #else
@@ -1047,7 +1067,7 @@ 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)
+   if ((transforms & PNG_TRANSFORM_STRIP_ALPHA) != 0)
 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
      png_set_strip_alpha(png_ptr);
 #else
@@ -1057,7 +1077,7 @@ 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)
+   if ((transforms & PNG_TRANSFORM_PACKING) != 0)
 #ifdef PNG_READ_PACK_SUPPORTED
      png_set_packing(png_ptr);
 #else
@@ -1067,7 +1087,7 @@ 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)
+   if ((transforms & PNG_TRANSFORM_PACKSWAP) != 0)
 #ifdef PNG_READ_PACKSWAP_SUPPORTED
      png_set_packswap(png_ptr);
 #else
@@ -1079,7 +1099,7 @@ 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)
+   if ((transforms & PNG_TRANSFORM_EXPAND) != 0)
 #ifdef PNG_READ_EXPAND_SUPPORTED
      png_set_expand(png_ptr);
 #else
@@ -1091,7 +1111,7 @@ 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)
+   if ((transforms & PNG_TRANSFORM_INVERT_MONO) != 0)
 #ifdef PNG_READ_INVERT_SUPPORTED
      png_set_invert_mono(png_ptr);
 #else
@@ -1102,16 +1122,16 @@ 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)
+   if ((transforms & PNG_TRANSFORM_SHIFT) != 0)
 #ifdef PNG_READ_SHIFT_SUPPORTED
-      if (info_ptr->valid & PNG_INFO_sBIT)
+      if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
         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)
+   if ((transforms & PNG_TRANSFORM_BGR) != 0)
 #ifdef PNG_READ_BGR_SUPPORTED
      png_set_bgr(png_ptr);
 #else
@@ -1119,7 +1139,7 @@ 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)
+   if ((transforms & PNG_TRANSFORM_SWAP_ALPHA) != 0)
 #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
      png_set_swap_alpha(png_ptr);
 #else
@@ -1127,7 +1147,7 @@ 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)
+   if ((transforms & PNG_TRANSFORM_SWAP_ENDIAN) != 0)
 #ifdef PNG_READ_SWAP_SUPPORTED
      png_set_swap(png_ptr);
 #else
@@ -1136,7 +1156,7 @@ 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)
+   if ((transforms & PNG_TRANSFORM_INVERT_ALPHA) != 0)
 #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
      png_set_invert_alpha(png_ptr);
 #else
@@ -1145,7 +1165,7 @@ 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)
+   if ((transforms & PNG_TRANSFORM_GRAY_TO_RGB) != 0)
 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
      png_set_gray_to_rgb(png_ptr);
 #else
@@ -1153,7 +1173,7 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,
 #endif

 /* Added at libpng-1.5.4 */
-   if (transforms & PNG_TRANSFORM_EXPAND_16)
+   if ((transforms & PNG_TRANSFORM_EXPAND_16) != 0)
 #ifdef PNG_READ_EXPAND_16_SUPPORTED
      png_set_expand_16(png_ptr);
 #else
@@ -1201,8 +1221,8 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,

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

 #ifdef PNG_SIMPLIFIED_READ_SUPPORTED
 /* SIMPLIFIED READ
@@ -1311,10 +1331,10 @@ png_image_format(png_structrp png_ptr)
 {
   png_uint_32 format = 0;

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

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

   /* Use png_ptr here, not info_ptr, because by examination png_handle_tRNS
@@ -1328,7 +1348,7 @@ 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)
+   if ((png_ptr->color_type & PNG_COLOR_MASK_PALETTE) != 0)
      format |= PNG_FORMAT_FLAG_COLORMAP;

   return format;
@@ -1428,7 +1448,7 @@ png_image_begin_read_from_stdio(png_imagep image, FILE* file)
   {
      if (file != NULL)
      {
-         if (png_image_read_init(image))
+         if (png_image_read_init(image) != 0)
         {
            /* 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
@@ -1462,7 +1482,7 @@ png_image_begin_read_from_file(png_imagep image, const char *file_name)

         if (fp != NULL)
         {
-            if (png_image_read_init(image))
+            if (png_image_read_init(image) != 0)
            {
               image->opaque->png_ptr->io_ptr = fp;
               image->opaque->owned_file = 1;
@@ -1488,7 +1508,7 @@ png_image_begin_read_from_file(png_imagep image, const char *file_name)

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

 static void PNGCBAPI
 png_image_memory_read(png_structp png_ptr, png_bytep out, png_size_t need)
@@ -1527,7 +1547,7 @@ int PNGAPI png_image_begin_read_from_memory(png_imagep image,
   {
      if (memory != NULL && size > 0)
      {
-         if (png_image_read_init(image))
+         if (png_image_read_init(image) != 0)
         {
            /* 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
@@ -1599,14 +1619,14 @@ 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, (sizeof chunks_to_process)/5);
+         chunks_to_process, (int)/*SAFE*/(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 /* PNG_HANDLE_AS_UNKNOWN_SUPPORTED */
+#endif /* HANDLE_AS_UNKNOWN */

 /* 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
@@ -1619,9 +1639,9 @@ 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))
+   if (png_gamma_significant(g) != 0)
   {
-      if (png_gamma_not_sRGB(g))
+      if (png_gamma_not_sRGB(g) != 0)
      {
         display->file_encoding = P_FILE;
         display->gamma_to_linear = png_reciprocal(g);
@@ -1716,7 +1736,7 @@ 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) ?
+   const int output_encoding = (image->format & PNG_FORMAT_FLAG_LINEAR) != 0 ?
      P_LINEAR : P_sRGB;
   const int convert_to_Y = (image->format & PNG_FORMAT_FLAG_COLOR) == 0 &&
      (red != green || green != blue);
@@ -1746,7 +1766,7 @@ 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 || output_encoding == P_LINEAR)
+      if (convert_to_Y != 0 || output_encoding == P_LINEAR)
      {
         alpha *= 257;
         encoding = P_LINEAR;
@@ -1773,7 +1793,8 @@ png_create_colormap_entry(png_image_read_control *display,
      encoding = P_LINEAR;
   }

-   else if (encoding == P_sRGB && (convert_to_Y || output_encoding == P_LINEAR))
+   else if (encoding == P_sRGB &&
+       (convert_to_Y  != 0 || output_encoding == P_LINEAR))
   {
      /* The values are 8-bit sRGB values, but must be converted to 16-bit
       * linear.
@@ -1831,7 +1852,7 @@ 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) ? 2 : 0;
+         const int bgr = (image->format & PNG_FORMAT_FLAG_BGR) != 0 ? 2 : 0;
 #     else
 #        define bgr 0
 #     endif
@@ -2043,7 +2064,7 @@ 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) ?
+   const int output_encoding = (output_format & PNG_FORMAT_FLAG_LINEAR) != 0 ?
      P_LINEAR : P_sRGB;

   unsigned int cmap_entries;
@@ -2082,7 +2103,7 @@ png_image_read_colormap(png_voidp argument)
      else
      {
         back_g = display->background->green;
-         if (output_format & PNG_FORMAT_FLAG_COLOR)
+         if ((output_format & PNG_FORMAT_FLAG_COLOR) != 0)
         {
            back_r = display->background->red;
            back_b = display->background->blue;
@@ -2224,7 +2245,7 @@ png_image_read_colormap(png_voidp argument)
            {
               unsigned int back_alpha;

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

               else
@@ -2305,7 +2326,7 @@ png_image_read_colormap(png_voidp argument)
          */
         data_encoding = P_sRGB;

-         if (output_format & PNG_FORMAT_FLAG_ALPHA)
+         if ((output_format & PNG_FORMAT_FLAG_ALPHA) != 0)
         {
            if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries)
               png_error(png_ptr, "gray+alpha color-map: too few entries");
@@ -2500,7 +2521,7 @@ 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))
+                  png_gamma_not_sRGB(png_ptr->colorspace.gamma) != 0)
               {
                  cmap_entries = make_gray_file_colormap(display);
                  data_encoding = P_FILE;
@@ -2588,7 +2609,7 @@ 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)
+               if ((output_format & PNG_FORMAT_FLAG_ALPHA) != 0)
               {
                  png_uint_32 r;

@@ -2762,7 +2783,7 @@ png_image_read_colormap(png_voidp argument)

            for (i=0; i < cmap_entries; ++i)
            {
-               if (do_background && i < num_trans && trans[i] < 255)
+               if (do_background != 0 && i < num_trans && trans[i] < 255)
               {
                  if (trans[i] == 0)
                     png_create_colormap_entry(display, i, back_r, back_g,
@@ -2807,8 +2828,8 @@ png_image_read_colormap(png_voidp argument)
   }

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

   switch (data_encoding)
@@ -3224,7 +3245,8 @@ 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) ? 3 : 1;
+      unsigned int channels =
+         (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ? 3 : 1;
      int pass;

      for (pass = 0; pass < passes; ++pass)
@@ -3522,7 +3544,8 @@ png_image_read_background(png_voidp argument)
            int swap_alpha = 0;

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

@@ -3631,10 +3654,10 @@ 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)
+      if ((change & PNG_FORMAT_FLAG_COLOR) != 0)
      {
         /* gray<->color transformation required. */
-         if (format & PNG_FORMAT_FLAG_COLOR)
+         if ((format & PNG_FORMAT_FLAG_COLOR) != 0)
            png_set_gray_to_rgb(png_ptr);

         else
@@ -3652,7 +3675,7 @@ 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)
+            if ((base_format & PNG_FORMAT_FLAG_ALPHA) != 0)
               do_local_background = 1/*maybe*/;

            png_set_rgb_to_gray_fixed(png_ptr, PNG_ERROR_ACTION_NONE,
@@ -3667,8 +3690,8 @@ png_image_read_direct(png_voidp argument)
      {
         png_fixed_point input_gamma_default;

-         if ((base_format & PNG_FORMAT_FLAG_LINEAR) &&
-            (image->flags & PNG_IMAGE_FLAG_16BIT_sRGB) == 0)
+         if ((base_format & PNG_FORMAT_FLAG_LINEAR) != 0 &&
+             (image->flags & PNG_IMAGE_FLAG_16BIT_sRGB) == 0)
            input_gamma_default = PNG_GAMMA_LINEAR;
         else
            input_gamma_default = PNG_DEFAULT_sRGB;
@@ -3684,7 +3707,7 @@ 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)
+         if ((base_format & PNG_FORMAT_FLAG_ALPHA) != 0)
            mode = PNG_ALPHA_STANDARD; /* associated alpha */

         else
@@ -3715,7 +3738,7 @@ png_image_read_direct(png_voidp argument)
          * final value.
          */
         if (png_muldiv(&gtest, output_gamma, png_ptr->colorspace.gamma,
-               PNG_FP_1) && !png_gamma_significant(gtest))
+               PNG_FP_1) != 0 && png_gamma_significant(gtest) == 0)
            do_local_background = 0;

         else if (mode == PNG_ALPHA_STANDARD)
@@ -3728,9 +3751,9 @@ png_image_read_direct(png_voidp argument)
      }

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

         else /* 8-bit output */
@@ -3740,13 +3763,13 @@ png_image_read_direct(png_voidp argument)
      }

      /* Now the background/alpha channel changes. */
-      if (change & PNG_FORMAT_FLAG_ALPHA)
+      if ((change & PNG_FORMAT_FLAG_ALPHA) != 0)
      {
         /* 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)
+         if ((base_format & PNG_FORMAT_FLAG_ALPHA) != 0)
         {
            /* If RGB->gray is happening the alpha channel must be left and the
             * operation completed locally.
@@ -3811,7 +3834,7 @@ png_image_read_direct(png_voidp argument)
               filler = 255;

 #           ifdef PNG_FORMAT_AFIRST_SUPPORTED
-               if (format & PNG_FORMAT_FLAG_AFIRST)
+               if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
               {
                  where = PNG_FILLER_BEFORE;
                  change &= ~PNG_FORMAT_FLAG_AFIRST;
@@ -3835,12 +3858,12 @@ 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)
+         if ((change & PNG_FORMAT_FLAG_BGR) != 0)
         {
            /* 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)
+            if ((format & PNG_FORMAT_FLAG_COLOR) != 0)
               png_set_bgr(png_ptr);

            else
@@ -3851,14 +3874,14 @@ png_image_read_direct(png_voidp argument)
 #     endif

 #     ifdef PNG_FORMAT_AFIRST_SUPPORTED
-         if (change & PNG_FORMAT_FLAG_AFIRST)
+         if ((change & PNG_FORMAT_FLAG_AFIRST) != 0)
         {
            /* 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)
+            if ((format & PNG_FORMAT_FLAG_ALPHA) != 0)
            {
               /* Disable this if doing a local background,
                * TODO: remove this when local background is no longer required.
@@ -3881,7 +3904,7 @@ png_image_read_direct(png_voidp argument)
      {
         PNG_CONST png_uint_16 le = 0x0001;

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

@@ -3906,10 +3929,10 @@ png_image_read_direct(png_voidp argument)
   {
      png_uint_32 info_format = 0;

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

-      if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
+      if ((info_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)
      {
         /* do_local_compose removes this channel below. */
         if (do_local_compose == 0)
@@ -3928,14 +3951,14 @@ png_image_read_direct(png_voidp argument)
         info_format |= PNG_FORMAT_FLAG_LINEAR;

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

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

@@ -4064,7 +4087,7 @@ 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)
+            if ((image->format & PNG_FORMAT_FLAG_COLORMAP) != 0)
               result =
                  png_safe_execute(image, png_image_read_colormap, &display) &&
                  png_safe_execute(image, png_image_read_colormapped, &display);
@@ -4094,5 +4117,5 @@ png_image_finish_read(png_imagep image, png_const_colorp background,
   return 0;
 }

-#endif /* PNG_SIMPLIFIED_READ_SUPPORTED */
-#endif /* PNG_READ_SUPPORTED */
+#endif /* SIMPLIFIED_READ */
+#endif /* READ */
--- a/pngrio.c
+++ b/pngrio.c
@@ -1,7 +1,7 @@

 /* pngrio.c - functions for data input
 *
- * Last changed in libpng 1.6.9 [February 6, 2014]
+ * Last changed in libpng 1.6.15 [November 20, 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 /* PNG_READ_SUPPORTED */
+#endif /* READ */
--- a/pngrtran.c
+++ b/pngrtran.c
@@ -1,7 +1,7 @@

 /* pngrtran.c - transforms the data in a row for PNG readers
 *
- * Last changed in libpng 1.6.11 [June 5, 2014]
+ * Last changed in libpng 1.6.15 [November 20, 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.)
@@ -91,14 +91,15 @@ png_set_crc_action(png_structrp png_ptr, int crit_action, int ancil_action)
 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
 /* Is it OK to set a transformation now?  Only if png_start_read_image or
 * png_read_update_info have not been called.  It is not necessary for the IHDR
- * to have been read in all cases, the parameter allows for this check too.
+ * to have been read in all cases; the need_IHDR parameter allows for this
+ * check too.
 */
 static int
 png_rtran_ok(png_structrp png_ptr, int need_IHDR)
 {
   if (png_ptr != NULL)
   {
-      if (png_ptr->flags & PNG_FLAG_ROW_INIT)
+      if ((png_ptr->flags & PNG_FLAG_ROW_INIT) != 0)
         png_app_error(png_ptr,
            "invalid after png_start_read_image or png_read_update_info");

@@ -127,7 +128,7 @@ png_set_background_fixed(png_structrp png_ptr,
 {
   png_debug(1, "in png_set_background_fixed");

-   if (!png_rtran_ok(png_ptr, 0) || background_color == NULL)
+   if (png_rtran_ok(png_ptr, 0) == 0 || background_color == NULL)
      return;

   if (background_gamma_code == PNG_BACKGROUND_GAMMA_UNKNOWN)
@@ -171,7 +172,7 @@ png_set_scale_16(png_structrp png_ptr)
 {
   png_debug(1, "in png_set_scale_16");

-   if (!png_rtran_ok(png_ptr, 0))
+   if (png_rtran_ok(png_ptr, 0) == 0)
      return;

   png_ptr->transformations |= PNG_SCALE_16_TO_8;
@@ -185,7 +186,7 @@ png_set_strip_16(png_structrp png_ptr)
 {
   png_debug(1, "in png_set_strip_16");

-   if (!png_rtran_ok(png_ptr, 0))
+   if (png_rtran_ok(png_ptr, 0) == 0)
      return;

   png_ptr->transformations |= PNG_16_TO_8;
@@ -198,7 +199,7 @@ png_set_strip_alpha(png_structrp png_ptr)
 {
   png_debug(1, "in png_set_strip_alpha");

-   if (!png_rtran_ok(png_ptr, 0))
+   if (png_rtran_ok(png_ptr, 0) == 0)
      return;

   png_ptr->transformations |= PNG_STRIP_ALPHA;
@@ -279,7 +280,7 @@ png_set_alpha_mode_fixed(png_structrp png_ptr, int mode,

   png_debug(1, "in png_set_alpha_mode");

-   if (!png_rtran_ok(png_ptr, 0))
+   if (png_rtran_ok(png_ptr, 0) == 0)
      return;

   output_gamma = translate_gamma_flags(png_ptr, output_gamma, 1/*screen*/);
@@ -371,7 +372,7 @@ png_set_alpha_mode_fixed(png_structrp png_ptr, int mode,
      png_ptr->background_gamma_type = PNG_BACKGROUND_GAMMA_FILE;
      png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND;

-      if (png_ptr->transformations & PNG_COMPOSE)
+      if ((png_ptr->transformations & PNG_COMPOSE) != 0)
         png_error(png_ptr,
            "conflicting calls to set alpha mode and background");

@@ -415,7 +416,7 @@ png_set_quantize(png_structrp png_ptr, png_colorp palette,
 {
   png_debug(1, "in png_set_quantize");

-   if (!png_rtran_ok(png_ptr, 0))
+   if (png_rtran_ok(png_ptr, 0) == 0)
      return;

   png_ptr->transformations |= PNG_QUANTIZE;
@@ -793,7 +794,7 @@ png_set_quantize(png_structrp png_ptr, png_colorp palette,
      png_free(png_ptr, distance);
   }
 }
-#endif /* PNG_READ_QUANTIZE_SUPPORTED */
+#endif /* READ_QUANTIZE */

 #ifdef PNG_READ_GAMMA_SUPPORTED
 void PNGFAPI
@@ -802,7 +803,7 @@ png_set_gamma_fixed(png_structrp png_ptr, png_fixed_point scrn_gamma,
 {
   png_debug(1, "in png_set_gamma_fixed");

-   if (!png_rtran_ok(png_ptr, 0))
+   if (png_rtran_ok(png_ptr, 0) == 0)
      return;

   /* New in libpng-1.5.4 - reserve particular negative values as flags. */
@@ -842,7 +843,7 @@ png_set_gamma(png_structrp png_ptr, double scrn_gamma, double file_gamma)
   png_set_gamma_fixed(png_ptr, convert_gamma_value(png_ptr, scrn_gamma),
      convert_gamma_value(png_ptr, file_gamma));
 }
-#  endif /* FLOATING_POINT_SUPPORTED */
+#  endif /* FLOATING_POINT */
 #endif /* READ_GAMMA */

 #ifdef PNG_READ_EXPAND_SUPPORTED
@@ -855,7 +856,7 @@ png_set_expand(png_structrp png_ptr)
 {
   png_debug(1, "in png_set_expand");

-   if (!png_rtran_ok(png_ptr, 0))
+   if (png_rtran_ok(png_ptr, 0) == 0)
      return;

   png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
@@ -885,7 +886,7 @@ png_set_palette_to_rgb(png_structrp png_ptr)
 {
   png_debug(1, "in png_set_palette_to_rgb");

-   if (!png_rtran_ok(png_ptr, 0))
+   if (png_rtran_ok(png_ptr, 0) == 0)
      return;

   png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
@@ -897,7 +898,7 @@ png_set_expand_gray_1_2_4_to_8(png_structrp png_ptr)
 {
   png_debug(1, "in png_set_expand_gray_1_2_4_to_8");

-   if (!png_rtran_ok(png_ptr, 0))
+   if (png_rtran_ok(png_ptr, 0) == 0)
      return;

   png_ptr->transformations |= PNG_EXPAND;
@@ -909,12 +910,12 @@ png_set_tRNS_to_alpha(png_structrp png_ptr)
 {
   png_debug(1, "in png_set_tRNS_to_alpha");

-   if (!png_rtran_ok(png_ptr, 0))
+   if (png_rtran_ok(png_ptr, 0) == 0)
      return;

   png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
 }
-#endif /* defined(PNG_READ_EXPAND_SUPPORTED) */
+#endif /* READ_EXPAND */

 #ifdef PNG_READ_EXPAND_16_SUPPORTED
 /* Expand to 16-bit channels, expand the tRNS chunk too (because otherwise
@@ -925,7 +926,7 @@ png_set_expand_16(png_structrp png_ptr)
 {
   png_debug(1, "in png_set_expand_16");

-   if (!png_rtran_ok(png_ptr, 0))
+   if (png_rtran_ok(png_ptr, 0) == 0)
      return;

   png_ptr->transformations |= (PNG_EXPAND_16 | PNG_EXPAND | PNG_EXPAND_tRNS);
@@ -938,7 +939,7 @@ png_set_gray_to_rgb(png_structrp png_ptr)
 {
   png_debug(1, "in png_set_gray_to_rgb");

-   if (!png_rtran_ok(png_ptr, 0))
+   if (png_rtran_ok(png_ptr, 0) == 0)
      return;

   /* Because rgb must be 8 bits or more: */
@@ -956,7 +957,7 @@ png_set_rgb_to_gray_fixed(png_structrp png_ptr, int error_action,

   /* Need the IHDR here because of the check on color_type below. */
   /* TODO: fix this */
-   if (!png_rtran_ok(png_ptr, 1))
+   if (png_rtran_ok(png_ptr, 1) == 0)
      return;

   switch (error_action)
@@ -998,7 +999,7 @@ png_set_rgb_to_gray_fixed(png_structrp png_ptr, int error_action,
         png_uint_16 red_int, green_int;

         /* NOTE: this calculation does not round, but this behavior is retained
-          * for consistency, the inaccuracy is very small.  The code here always
+          * for consistency; the inaccuracy is very small.  The code here always
          * overwrites the coefficients, regardless of whether they have been
          * defaulted or set already.
          */
@@ -1091,7 +1092,7 @@ png_gamma_threshold(png_fixed_point screen_gamma, png_fixed_point file_gamma)
 * the palette.
 */

-/*For the moment 'png_init_palette_transformations' and
+/* For the moment 'png_init_palette_transformations' and
 * 'png_init_rgb_transformations' only do some flag canceling optimizations.
 * The intent is that these two routines should have palette or rgb operations
 * extracted from 'png_init_read_transformations'.
@@ -1153,8 +1154,8 @@ png_init_palette_transformations(png_structrp png_ptr)
   /* The following code cannot be entered in the alpha pre-multiplication case
    * because PNG_BACKGROUND_EXPAND is cancelled below.
    */
-   if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
-       (png_ptr->transformations & PNG_EXPAND))
+   if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) != 0 &&
+       (png_ptr->transformations & PNG_EXPAND) != 0)
   {
      {
         png_ptr->background.red   =
@@ -1165,9 +1166,9 @@ png_init_palette_transformations(png_structrp png_ptr)
             png_ptr->palette[png_ptr->background.index].blue;

 #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
-        if (png_ptr->transformations & PNG_INVERT_ALPHA)
+        if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0)
        {
-           if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
+           if ((png_ptr->transformations & PNG_EXPAND_tRNS) == 0)
           {
              /* Invert the alpha channel (in tRNS) unless the pixels are
               * going to be expanded, in which case leave it for later
@@ -1179,10 +1180,10 @@ png_init_palette_transformations(png_structrp png_ptr)
                    png_ptr->trans_alpha[i]);
           }
        }
-#endif /* PNG_READ_INVERT_ALPHA_SUPPORTED */
+#endif /* READ_INVERT_ALPHA */
      }
   } /* background expand and (therefore) no alpha association. */
-#endif /* PNG_READ_EXPAND_SUPPORTED && PNG_READ_BACKGROUND_SUPPORTED */
+#endif /* READ_EXPAND && READ_BACKGROUND */
 }

 static void /* PRIVATE */
@@ -1220,9 +1221,9 @@ png_init_rgb_transformations(png_structrp png_ptr)
   /* The following code cannot be entered in the alpha pre-multiplication case
    * because PNG_BACKGROUND_EXPAND is cancelled below.
    */
-   if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
-       (png_ptr->transformations & PNG_EXPAND) &&
-       !(png_ptr->color_type & PNG_COLOR_MASK_COLOR))
+   if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) != 0 &&
+       (png_ptr->transformations & PNG_EXPAND) != 0 &&
+       (png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
       /* i.e., GRAY or GRAY_ALPHA */
   {
      {
@@ -1260,14 +1261,14 @@ png_init_rgb_transformations(png_structrp png_ptr)
         png_ptr->background.red = png_ptr->background.green =
            png_ptr->background.blue = (png_uint_16)gray;

-         if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
+         if ((png_ptr->transformations & PNG_EXPAND_tRNS) == 0)
         {
            png_ptr->trans_color.red = png_ptr->trans_color.green =
               png_ptr->trans_color.blue = (png_uint_16)trans_gray;
         }
      }
   } /* background expand and (therefore) no alpha association. */
-#endif /* PNG_READ_EXPAND_SUPPORTED && PNG_READ_BACKGROUND_SUPPORTED */
+#endif /* READ_EXPAND && READ_BACKGROUND */
 }

 void /* PRIVATE */
@@ -1345,7 +1346,7 @@ png_init_read_transformations(png_structrp png_ptr)
 #endif

   /* Certain transformations have the effect of preventing other
-    * transformations that happen afterward in png_do_read_transformations,
+    * transformations that happen afterward in png_do_read_transformations;
    * resolve the interdependencies here.  From the code of
    * png_do_read_transformations the order is:
    *
@@ -1374,8 +1375,8 @@ png_init_read_transformations(png_structrp png_ptr)
    * 23) PNG_USER_TRANSFORM [must be last]
    */
 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
-   if ((png_ptr->transformations & PNG_STRIP_ALPHA) &&
-      !(png_ptr->transformations & PNG_COMPOSE))
+   if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0 &&
+       (png_ptr->transformations & PNG_COMPOSE) == 0)
   {
      /* Stripping the alpha channel happens immediately after the 'expand'
       * transformations, before all other transformation, so it cancels out
@@ -1401,7 +1402,7 @@ png_init_read_transformations(png_structrp png_ptr)
   /* If the screen gamma is about 1.0 then the OPTIMIZE_ALPHA and ENCODE_ALPHA
    * settings will have no effect.
    */
-   if (!png_gamma_significant(png_ptr->screen_gamma))
+   if (png_gamma_significant(png_ptr->screen_gamma) == 0)
   {
      png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
      png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
@@ -1412,7 +1413,7 @@ png_init_read_transformations(png_structrp png_ptr)
   /* Make sure the coefficients for the rgb to gray conversion are set
    * appropriately.
    */
-   if (png_ptr->transformations & PNG_RGB_TO_GRAY)
+   if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
      png_colorspace_set_rgb_coefficients(png_ptr);
 #endif

@@ -1433,23 +1434,23 @@ png_init_read_transformations(png_structrp png_ptr)
    * png_set_background, along with the bit depth, then the code has a record
    * of exactly what color space the background is currently in.
    */
-   if (png_ptr->transformations & PNG_BACKGROUND_EXPAND)
+   if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) != 0)
   {
      /* PNG_BACKGROUND_EXPAND: the background is in the file color space, so if
       * the file was grayscale the background value is gray.
       */
-      if (!(png_ptr->color_type & PNG_COLOR_MASK_COLOR))
+      if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
         png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
   }

-   else if (png_ptr->transformations & PNG_COMPOSE)
+   else if ((png_ptr->transformations & PNG_COMPOSE) != 0)
   {
      /* PNG_COMPOSE: png_set_background was called with need_expand false,
       * so the color is in the color space of the output or png_set_alpha_mode
       * was called and the color is black.  Ignore RGB_TO_GRAY because that
       * happens before GRAY_TO_RGB.
       */
-      if (png_ptr->transformations & PNG_GRAY_TO_RGB)
+      if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0)
      {
         if (png_ptr->background.red == png_ptr->background.green &&
             png_ptr->background.red == png_ptr->background.blue)
@@ -1459,8 +1460,8 @@ png_init_read_transformations(png_structrp png_ptr)
         }
      }
   }
-#endif /* PNG_READ_EXPAND_SUPPORTED && PNG_READ_BACKGROUND_SUPPORTED */
-#endif /* PNG_READ_GRAY_TO_RGB_SUPPORTED */
+#endif /* READ_EXPAND && READ_BACKGROUND */
+#endif /* READ_GRAY_TO_RGB */

   /* For indexed PNG data (PNG_COLOR_TYPE_PALETTE) many of the transformations
    * can be performed directly on the palette, and some (such as rgb to gray)
@@ -1481,10 +1482,10 @@ png_init_read_transformations(png_structrp png_ptr)

 #if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
   defined(PNG_READ_EXPAND_16_SUPPORTED)
-   if ((png_ptr->transformations & PNG_EXPAND_16) &&
-      (png_ptr->transformations & PNG_COMPOSE) &&
-      !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
-      png_ptr->bit_depth != 16)
+   if ((png_ptr->transformations & PNG_EXPAND_16) != 0 &&
+       (png_ptr->transformations & PNG_COMPOSE) != 0 &&
+       (png_ptr->transformations & PNG_BACKGROUND_EXPAND) == 0 &&
+       png_ptr->bit_depth != 16)
   {
      /* TODO: fix this.  Because the expand_16 operation is after the compose
       * handling the background color must be 8, not 16, bits deep, but the
@@ -1503,15 +1504,15 @@ png_init_read_transformations(png_structrp png_ptr)
      CHOP(png_ptr->background.gray);
 #     undef CHOP
   }
-#endif /* PNG_READ_BACKGROUND_SUPPORTED && PNG_READ_EXPAND_16_SUPPORTED */
+#endif /* READ_BACKGROUND && READ_EXPAND_16 */

 #if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
   (defined(PNG_READ_SCALE_16_TO_8_SUPPORTED) || \
   defined(PNG_READ_STRIP_16_TO_8_SUPPORTED))
-   if ((png_ptr->transformations & (PNG_16_TO_8|PNG_SCALE_16_TO_8)) &&
-      (png_ptr->transformations & PNG_COMPOSE) &&
-      !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
-      png_ptr->bit_depth == 16)
+   if ((png_ptr->transformations & (PNG_16_TO_8|PNG_SCALE_16_TO_8)) != 0 &&
+       (png_ptr->transformations & PNG_COMPOSE) != 0 &&
+       (png_ptr->transformations & PNG_BACKGROUND_EXPAND) == 0 &&
+       png_ptr->bit_depth == 16)
   {
      /* On the other hand, if a 16-bit file is to be reduced to 8-bits per
       * component this will also happen after PNG_COMPOSE and so the background
@@ -1554,25 +1555,24 @@ png_init_read_transformations(png_structrp png_ptr)
    * file gamma - if it is not 1.0 both RGB_TO_GRAY and COMPOSE need the
    * tables.
    */
-   if ((png_ptr->transformations & PNG_GAMMA)
-      || ((png_ptr->transformations & PNG_RGB_TO_GRAY)
-         && (png_gamma_significant(png_ptr->colorspace.gamma) ||
-            png_gamma_significant(png_ptr->screen_gamma)))
-      || ((png_ptr->transformations & PNG_COMPOSE)
-         && (png_gamma_significant(png_ptr->colorspace.gamma)
-            || png_gamma_significant(png_ptr->screen_gamma)
+   if ((png_ptr->transformations & PNG_GAMMA) != 0 ||
+       ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0 &&
+        (png_gamma_significant(png_ptr->colorspace.gamma) != 0 ||
+         png_gamma_significant(png_ptr->screen_gamma) != 0)) ||
+        ((png_ptr->transformations & PNG_COMPOSE) != 0 &&
+         (png_gamma_significant(png_ptr->colorspace.gamma) != 0 ||
+          png_gamma_significant(png_ptr->screen_gamma) != 0
 #  ifdef PNG_READ_BACKGROUND_SUPPORTED
-            || (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_UNIQUE
-               && png_gamma_significant(png_ptr->background_gamma))
+         || (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_UNIQUE &&
+           png_gamma_significant(png_ptr->background_gamma) != 0)
 #  endif
-      )) || ((png_ptr->transformations & PNG_ENCODE_ALPHA)
-         && png_gamma_significant(png_ptr->screen_gamma))
-      )
+        )) || ((png_ptr->transformations & PNG_ENCODE_ALPHA) != 0 &&
+       png_gamma_significant(png_ptr->screen_gamma) != 0))
   {
      png_build_gamma_table(png_ptr, png_ptr->bit_depth);

 #ifdef PNG_READ_BACKGROUND_SUPPORTED
-      if (png_ptr->transformations & PNG_COMPOSE)
+      if ((png_ptr->transformations & PNG_COMPOSE) != 0)
      {
         /* Issue a warning about this combination: because RGB_TO_GRAY is
          * optimized to do the gamma transform if present yet do_background has
@@ -1580,11 +1580,11 @@ png_init_read_transformations(png_structrp png_ptr)
          * double-gamma-correction happens.  This is true in all versions of
          * libpng to date.
          */
-         if (png_ptr->transformations & PNG_RGB_TO_GRAY)
+         if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
            png_warning(png_ptr,
               "libpng does not support gamma+background+rgb_to_gray");

-         if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+         if ((png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) != 0)
         {
            /* We don't get to here unless there is a tRNS chunk with non-opaque
             * entries - see the checking code at the start of this function.
@@ -1632,7 +1632,7 @@ png_init_read_transformations(png_structrp png_ptr)
                     break;
               }

-               if (png_gamma_significant(gs))
+               if (png_gamma_significant(gs) != 0)
               {
                  back.red = png_gamma_8bit_correct(png_ptr->background.red,
                      gs);
@@ -1649,7 +1649,7 @@ png_init_read_transformations(png_structrp png_ptr)
                  back.blue  = (png_byte)png_ptr->background.blue;
               }

-               if (png_gamma_significant(g))
+               if (png_gamma_significant(g) != 0)
               {
                  back_1.red = png_gamma_8bit_correct(png_ptr->background.red,
                     g);
@@ -1798,7 +1798,7 @@ png_init_read_transformations(png_structrp png_ptr)

      else
      /* Transformation does not include PNG_BACKGROUND */
-#endif /* PNG_READ_BACKGROUND_SUPPORTED */
+#endif /* READ_BACKGROUND */
      if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE
 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
         /* RGB_TO_GRAY needs to have non-gamma-corrected values! */
@@ -1828,11 +1828,11 @@ png_init_read_transformations(png_structrp png_ptr)
 #ifdef PNG_READ_BACKGROUND_SUPPORTED
   else
 #endif
-#endif /* PNG_READ_GAMMA_SUPPORTED */
+#endif /* READ_GAMMA */

 #ifdef PNG_READ_BACKGROUND_SUPPORTED
   /* No GAMMA transformation (see the hanging else 4 lines above) */
-   if ((png_ptr->transformations & PNG_COMPOSE) &&
+   if ((png_ptr->transformations & PNG_COMPOSE) != 0 &&
       (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
   {
      int i;
@@ -1867,11 +1867,11 @@ png_init_read_transformations(png_structrp png_ptr)

      png_ptr->transformations &= ~PNG_COMPOSE;
   }
-#endif /* PNG_READ_BACKGROUND_SUPPORTED */
+#endif /* READ_BACKGROUND */

 #ifdef PNG_READ_SHIFT_SUPPORTED
-   if ((png_ptr->transformations & PNG_SHIFT) &&
-      !(png_ptr->transformations & PNG_EXPAND) &&
+   if ((png_ptr->transformations & PNG_SHIFT) != 0 &&
+       (png_ptr->transformations & PNG_EXPAND) == 0 &&
       (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
   {
      int i;
@@ -1913,7 +1913,7 @@ png_init_read_transformations(png_structrp png_ptr)
            png_ptr->palette[i].blue = (png_byte)component;
         }
   }
-#endif  /* PNG_READ_SHIFT_SUPPORTED */
+#endif  /* READ_SHIFT */
 }

 /* Modify the info structure to reflect the transformations.  The
@@ -1926,7 +1926,7 @@ png_read_transform_info(png_structrp png_ptr, png_inforp info_ptr)
   png_debug(1, "in png_read_transform_info");

 #ifdef PNG_READ_EXPAND_SUPPORTED
-   if (png_ptr->transformations & PNG_EXPAND)
+   if ((png_ptr->transformations & PNG_EXPAND) != 0)
   {
      if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
      {
@@ -1948,9 +1948,9 @@ png_read_transform_info(png_structrp png_ptr, png_inforp info_ptr)
      }
      else
      {
-         if (png_ptr->num_trans)
+         if (png_ptr->num_trans != 0)
         {
-            if (png_ptr->transformations & PNG_EXPAND_tRNS)
+            if ((png_ptr->transformations & PNG_EXPAND_tRNS) != 0)
               info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
         }
         if (info_ptr->bit_depth < 8)
@@ -1966,7 +1966,7 @@ png_read_transform_info(png_structrp png_ptr, png_inforp info_ptr)
   /* The following is almost certainly wrong unless the background value is in
    * the screen space!
    */
-   if (png_ptr->transformations & PNG_COMPOSE)
+   if ((png_ptr->transformations & PNG_COMPOSE) != 0)
      info_ptr->background = png_ptr->background;
 #endif

@@ -1987,12 +1987,12 @@ png_read_transform_info(png_structrp png_ptr, png_inforp info_ptr)
   {
 #  ifdef PNG_READ_16BIT_SUPPORTED
 #     ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
-         if (png_ptr->transformations & PNG_SCALE_16_TO_8)
+         if ((png_ptr->transformations & PNG_SCALE_16_TO_8) != 0)
            info_ptr->bit_depth = 8;
 #     endif

 #     ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
-         if (png_ptr->transformations & PNG_16_TO_8)
+         if ((png_ptr->transformations & PNG_16_TO_8) != 0)
            info_ptr->bit_depth = 8;
 #     endif

@@ -2018,27 +2018,27 @@ png_read_transform_info(png_structrp png_ptr, png_inforp info_ptr)
            CONFIGURATION ERROR: you must enable at least one 16 to 8 method
 #        endif
 #    endif
-#endif /* !READ_16BIT_SUPPORTED */
+#endif /* !READ_16BIT */
   }

 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
-   if (png_ptr->transformations & PNG_GRAY_TO_RGB)
+   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0)
      info_ptr->color_type = (png_byte)(info_ptr->color_type |
         PNG_COLOR_MASK_COLOR);
 #endif

 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
-   if (png_ptr->transformations & PNG_RGB_TO_GRAY)
+   if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
      info_ptr->color_type = (png_byte)(info_ptr->color_type &
         ~PNG_COLOR_MASK_COLOR);
 #endif

 #ifdef PNG_READ_QUANTIZE_SUPPORTED
-   if (png_ptr->transformations & PNG_QUANTIZE)
+   if ((png_ptr->transformations & PNG_QUANTIZE) != 0)
   {
      if (((info_ptr->color_type == PNG_COLOR_TYPE_RGB) ||
          (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)) &&
-          png_ptr->palette_lookup && info_ptr->bit_depth == 8)
+          png_ptr->palette_lookup != 0 && info_ptr->bit_depth == 8)
      {
         info_ptr->color_type = PNG_COLOR_TYPE_PALETTE;
      }
@@ -2046,29 +2046,31 @@ png_read_transform_info(png_structrp png_ptr, png_inforp info_ptr)
 #endif

 #ifdef PNG_READ_EXPAND_16_SUPPORTED
-   if (png_ptr->transformations & PNG_EXPAND_16 && info_ptr->bit_depth == 8 &&
-      info_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
+   if ((png_ptr->transformations & PNG_EXPAND_16) != 0 &&
+       info_ptr->bit_depth == 8 &&
+       info_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
   {
      info_ptr->bit_depth = 16;
   }
 #endif

 #ifdef PNG_READ_PACK_SUPPORTED
-   if ((png_ptr->transformations & PNG_PACK) && (info_ptr->bit_depth < 8))
+   if ((png_ptr->transformations & PNG_PACK) != 0 &&
+       (info_ptr->bit_depth < 8))
      info_ptr->bit_depth = 8;
 #endif

   if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
      info_ptr->channels = 1;

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

   else
      info_ptr->channels = 1;

 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
-   if (png_ptr->transformations & PNG_STRIP_ALPHA)
+   if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0)
   {
      info_ptr->color_type = (png_byte)(info_ptr->color_type &
         ~PNG_COLOR_MASK_ALPHA);
@@ -2076,25 +2078,25 @@ png_read_transform_info(png_structrp png_ptr, png_inforp info_ptr)
   }
 #endif

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

 #ifdef PNG_READ_FILLER_SUPPORTED
   /* STRIP_ALPHA and FILLER allowed:  MASK_ALPHA bit stripped above */
-   if ((png_ptr->transformations & PNG_FILLER) &&
-       ((info_ptr->color_type == PNG_COLOR_TYPE_RGB) ||
-       (info_ptr->color_type == PNG_COLOR_TYPE_GRAY)))
+   if ((png_ptr->transformations & PNG_FILLER) != 0 &&
+       (info_ptr->color_type == PNG_COLOR_TYPE_RGB ||
+       info_ptr->color_type == PNG_COLOR_TYPE_GRAY))
   {
      info_ptr->channels++;
      /* If adding a true alpha channel not just filler */
-      if (png_ptr->transformations & PNG_ADD_ALPHA)
+      if ((png_ptr->transformations & PNG_ADD_ALPHA) != 0)
         info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
   }
 #endif

 #if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) && \
 defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
-   if (png_ptr->transformations & PNG_USER_TRANSFORM)
+   if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
   {
      if (info_ptr->bit_depth < png_ptr->user_transform_depth)
         info_ptr->bit_depth = png_ptr->user_transform_depth;
@@ -2245,7 +2247,7 @@ png_do_unshift(png_row_infop row_info, png_bytep row,
      int channels = 0;
      int bit_depth = row_info->bit_depth;

-      if (color_type & PNG_COLOR_MASK_COLOR)
+      if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
      {
         shift[channels++] = bit_depth - sig_bits->red;
         shift[channels++] = bit_depth - sig_bits->green;
@@ -2257,7 +2259,7 @@ png_do_unshift(png_row_infop row_info, png_bytep row,
         shift[channels++] = bit_depth - sig_bits->gray;
      }

-      if (color_type & PNG_COLOR_MASK_ALPHA)
+      if ((color_type & PNG_COLOR_MASK_ALPHA) != 0)
      {
         shift[channels++] = bit_depth - sig_bits->alpha;
      }
@@ -2671,7 +2673,7 @@ png_do_read_filler(png_row_infop row_info, png_bytep row,
   {
      if (row_info->bit_depth == 8)
      {
-         if (flags & PNG_FLAG_FILLER_AFTER)
+         if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
         {
            /* This changes the data from G to GX */
            png_bytep sp = row + (png_size_t)row_width;
@@ -2706,7 +2708,7 @@ png_do_read_filler(png_row_infop row_info, png_bytep row,
 #ifdef PNG_READ_16BIT_SUPPORTED
      else if (row_info->bit_depth == 16)
      {
-         if (flags & PNG_FLAG_FILLER_AFTER)
+         if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
         {
            /* This changes the data from GG to GGXX */
            png_bytep sp = row + (png_size_t)row_width * 2;
@@ -2748,7 +2750,7 @@ png_do_read_filler(png_row_infop row_info, png_bytep row,
   {
      if (row_info->bit_depth == 8)
      {
-         if (flags & PNG_FLAG_FILLER_AFTER)
+         if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
         {
            /* This changes the data from RGB to RGBX */
            png_bytep sp = row + (png_size_t)row_width * 3;
@@ -2787,7 +2789,7 @@ png_do_read_filler(png_row_infop row_info, png_bytep row,
 #ifdef PNG_READ_16BIT_SUPPORTED
      else if (row_info->bit_depth == 16)
      {
-         if (flags & PNG_FLAG_FILLER_AFTER)
+         if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
         {
            /* This changes the data from RRGGBB to RRGGBBXX */
            png_bytep sp = row + (png_size_t)row_width * 6;
@@ -2848,7 +2850,7 @@ png_do_gray_to_rgb(png_row_infop row_info, png_bytep row)
   png_debug(1, "in png_do_gray_to_rgb");

   if (row_info->bit_depth >= 8 &&
-       !(row_info->color_type & PNG_COLOR_MASK_COLOR))
+       (row_info->color_type & PNG_COLOR_MASK_COLOR) == 0)
   {
      if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
      {
@@ -2986,8 +2988,8 @@ png_do_rgb_to_gray(png_structrp png_ptr, png_row_infop row_info, png_bytep row)

   png_debug(1, "in png_do_rgb_to_gray");

-   if (!(row_info->color_type & PNG_COLOR_MASK_PALETTE) &&
-       (row_info->color_type & PNG_COLOR_MASK_COLOR))
+   if ((row_info->color_type & PNG_COLOR_MASK_PALETTE) == 0 &&
+       (row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
   {
      PNG_CONST png_uint_32 rc = png_ptr->rgb_to_gray_red_coeff;
      PNG_CONST png_uint_32 gc = png_ptr->rgb_to_gray_green_coeff;
@@ -3086,15 +3088,15 @@ png_do_rgb_to_gray(png_structrp png_ptr, png_row_infop row_info, png_bytep row)
            {
               png_uint_16 red, green, blue, w;

-               red   = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
-               green = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
-               blue  = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
+               red   = (png_uint_16)(((*(sp)) << 8) | *(sp + 1)); sp += 2;
+               green = (png_uint_16)(((*(sp)) << 8) | *(sp + 1)); sp += 2;
+               blue  = (png_uint_16)(((*(sp)) << 8) | *(sp + 1)); sp += 2;

               if (red == green && red == blue)
               {
                  if (png_ptr->gamma_16_table != NULL)
-                     w = png_ptr->gamma_16_table[(red&0xff)
-                         >> png_ptr->gamma_shift][red>>8];
+                     w = png_ptr->gamma_16_table[(red & 0xff)
+                         >> png_ptr->gamma_shift][red >> 8];

                  else
                     w = red;
@@ -3137,9 +3139,9 @@ png_do_rgb_to_gray(png_structrp png_ptr, png_row_infop row_info, png_bytep row)
            {
               png_uint_16 red, green, blue, gray16;

-               red   = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
-               green = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
-               blue  = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
+               red   = (png_uint_16)(((*(sp)) << 8) | *(sp + 1)); sp += 2;
+               green = (png_uint_16)(((*(sp)) << 8) | *(sp + 1)); sp += 2;
+               blue  = (png_uint_16)(((*(sp)) << 8) | *(sp + 1)); sp += 2;

               if (red != green || red != blue)
                  rgb_error |= 1;
@@ -3150,7 +3152,7 @@ png_do_rgb_to_gray(png_structrp png_ptr, png_row_infop row_info, png_bytep row)
                */
               gray16  = (png_uint_16)((rc*red + gc*green + bc*blue + 16384) >>
                  15);
-               *(dp++) = (png_byte)((gray16>>8) & 0xff);
+               *(dp++) = (png_byte)((gray16 >> 8) & 0xff);
               *(dp++) = (png_byte)(gray16 & 0xff);

               if (have_alpha != 0)
@@ -3910,7 +3912,7 @@ png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
      }
   }
 }
-#endif /* PNG_READ_BACKGROUND_SUPPORTED || PNG_READ_ALPHA_MODE_SUPPORTED */
+#endif /* READ_BACKGROUND || READ_ALPHA_MODE */

 #ifdef PNG_READ_GAMMA_SUPPORTED
 /* Gamma correct the image, avoiding the alpha channel.  Make sure
@@ -4127,7 +4129,7 @@ png_do_encode_alpha(png_row_infop row_info, png_bytep row, png_structrp png_ptr)

   png_debug(1, "in png_do_encode_alpha");

-   if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
+   if ((row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0)
   {
      if (row_info->bit_depth == 8)
      {
@@ -4353,7 +4355,7 @@ png_do_expand(png_row_infop row_info, png_bytep row,
   {
      if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
      {
-         unsigned int gray = trans_color ? trans_color->gray : 0;
+         unsigned int gray = trans_color != NULL ? trans_color->gray : 0;

         if (row_info->bit_depth < 8)
         {
@@ -4497,7 +4499,8 @@ png_do_expand(png_row_infop row_info, png_bytep row,
               row_width);
         }
      }
-      else if (row_info->color_type == PNG_COLOR_TYPE_RGB && trans_color)
+      else if (row_info->color_type == PNG_COLOR_TYPE_RGB &&
+          trans_color != NULL)
      {
         if (row_info->bit_depth == 8)
         {
@@ -4688,7 +4691,7 @@ png_do_quantize(png_row_infop row_info, png_bytep row,
      }
   }
 }
-#endif /* PNG_READ_QUANTIZE_SUPPORTED */
+#endif /* READ_QUANTIZE */

 /* Transform the row.  The order of transformations is significant,
 * and is very touchy.  If you add a transformation, take care to
@@ -4715,7 +4718,7 @@ png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
    * demand, if necessary.
    */
   if ((png_ptr->flags & PNG_FLAG_DETECT_UNINITIALIZED) != 0 &&
-      !(png_ptr->flags & PNG_FLAG_ROW_INIT))
+       (png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
   {
      /* Application has failed to call either png_read_start_image() or
       * png_read_update_info() after setting transforms that expand pixels.
@@ -4725,7 +4728,7 @@ png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
   }

 #ifdef PNG_READ_EXPAND_SUPPORTED
-   if (png_ptr->transformations & PNG_EXPAND)
+   if ((png_ptr->transformations & PNG_EXPAND) != 0)
   {
      if (row_info->color_type == PNG_COLOR_TYPE_PALETTE)
      {
@@ -4735,8 +4738,8 @@ png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)

      else
      {
-         if (png_ptr->num_trans &&
-             (png_ptr->transformations & PNG_EXPAND_tRNS))
+         if (png_ptr->num_trans != 0 &&
+             (png_ptr->transformations & PNG_EXPAND_tRNS) != 0)
            png_do_expand(row_info, png_ptr->row_buf + 1,
                &(png_ptr->trans_color));

@@ -4748,16 +4751,16 @@ png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
 #endif

 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
-   if ((png_ptr->transformations & PNG_STRIP_ALPHA) &&
-      !(png_ptr->transformations & PNG_COMPOSE) &&
-      (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
-      row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
+   if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0 &&
+       (png_ptr->transformations & PNG_COMPOSE) == 0 &&
+       (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
+       row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
      png_do_strip_channel(row_info, png_ptr->row_buf + 1,
         0 /* at_start == false, because SWAP_ALPHA happens later */);
 #endif

 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
-   if (png_ptr->transformations & PNG_RGB_TO_GRAY)
+   if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
   {
      int rgb_error =
          png_do_rgb_to_gray(png_ptr, row_info,
@@ -4812,22 +4815,22 @@ png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
   /* If gray -> RGB, do so now only if background is non-gray; else do later
    * for performance reasons
    */
-   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
-       !(png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
+   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0 &&
+       (png_ptr->mode & PNG_BACKGROUND_IS_GRAY) == 0)
      png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
 #endif

 #if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
-   if (png_ptr->transformations & PNG_COMPOSE)
+   if ((png_ptr->transformations & PNG_COMPOSE) != 0)
      png_do_compose(row_info, png_ptr->row_buf + 1, png_ptr);
 #endif

 #ifdef PNG_READ_GAMMA_SUPPORTED
-   if ((png_ptr->transformations & PNG_GAMMA) &&
+   if ((png_ptr->transformations & PNG_GAMMA) != 0 &&
 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
      /* Because RGB_TO_GRAY does the gamma transform. */
-      !(png_ptr->transformations & PNG_RGB_TO_GRAY) &&
+      (png_ptr->transformations & PNG_RGB_TO_GRAY) == 0 &&
 #endif
 #if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
@@ -4836,7 +4839,7 @@ png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
       */
       !((png_ptr->transformations & PNG_COMPOSE) &&
       ((png_ptr->num_trans != 0) ||
-       (png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) &&
+       (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)) &&
 #endif
      /* Because png_init_read_transformations transforms the palette, unless
       * RGB_TO_GRAY will do the transform.
@@ -4846,22 +4849,22 @@ png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
 #endif

 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
-   if ((png_ptr->transformations & PNG_STRIP_ALPHA) &&
-      (png_ptr->transformations & PNG_COMPOSE) &&
-      (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
-      row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
+   if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0 &&
+       (png_ptr->transformations & PNG_COMPOSE) != 0 &&
+       (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
+       row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
      png_do_strip_channel(row_info, png_ptr->row_buf + 1,
-         0 /* at_start == false, because SWAP_ALPHA happens later */);
+          0 /* at_start == false, because SWAP_ALPHA happens later */);
 #endif

 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
-   if ((png_ptr->transformations & PNG_ENCODE_ALPHA) &&
-      (row_info->color_type & PNG_COLOR_MASK_ALPHA))
+   if ((png_ptr->transformations & PNG_ENCODE_ALPHA) != 0 &&
+       (row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0)
      png_do_encode_alpha(row_info, png_ptr->row_buf + 1, png_ptr);
 #endif

 #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
-   if (png_ptr->transformations & PNG_SCALE_16_TO_8)
+   if ((png_ptr->transformations & PNG_SCALE_16_TO_8) != 0)
      png_do_scale_16_to_8(row_info, png_ptr->row_buf + 1);
 #endif

@@ -4870,12 +4873,12 @@ png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
    * by putting the 'scale' option first if the app asks for scale (either by
    * calling the API or in a TRANSFORM flag) this is what happens.
    */
-   if (png_ptr->transformations & PNG_16_TO_8)
+   if ((png_ptr->transformations & PNG_16_TO_8) != 0)
      png_do_chop(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_READ_QUANTIZE_SUPPORTED
-   if (png_ptr->transformations & PNG_QUANTIZE)
+   if ((png_ptr->transformations & PNG_QUANTIZE) != 0)
   {
      png_do_quantize(row_info, png_ptr->row_buf + 1,
          png_ptr->palette_lookup, png_ptr->quantize_index);
@@ -4883,7 +4886,7 @@ png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
      if (row_info->rowbytes == 0)
         png_error(png_ptr, "png_do_quantize returned rowbytes=0");
   }
-#endif /* PNG_READ_QUANTIZE_SUPPORTED */
+#endif /* READ_QUANTIZE */

 #ifdef PNG_READ_EXPAND_16_SUPPORTED
   /* Do the expansion now, after all the arithmetic has been done.  Notice
@@ -4891,35 +4894,35 @@ png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
    * is efficient (particularly true in the case of gamma correction, where
    * better accuracy results faster!)
    */
-   if (png_ptr->transformations & PNG_EXPAND_16)
+   if ((png_ptr->transformations & PNG_EXPAND_16) != 0)
      png_do_expand_16(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
   /* NOTE: moved here in 1.5.4 (from much later in this list.) */
-   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
-       (png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
+   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0 &&
+       (png_ptr->mode & PNG_BACKGROUND_IS_GRAY) != 0)
      png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_READ_INVERT_SUPPORTED
-   if (png_ptr->transformations & PNG_INVERT_MONO)
+   if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
      png_do_invert(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
-   if (png_ptr->transformations & PNG_INVERT_ALPHA)
+   if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0)
      png_do_read_invert_alpha(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_READ_SHIFT_SUPPORTED
-   if (png_ptr->transformations & PNG_SHIFT)
+   if ((png_ptr->transformations & PNG_SHIFT) != 0)
      png_do_unshift(row_info, png_ptr->row_buf + 1,
          &(png_ptr->shift));
 #endif

 #ifdef PNG_READ_PACK_SUPPORTED
-   if (png_ptr->transformations & PNG_PACK)
+   if ((png_ptr->transformations & PNG_PACK) != 0)
      png_do_unpack(row_info, png_ptr->row_buf + 1);
 #endif

@@ -4931,36 +4934,36 @@ png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
 #endif

 #ifdef PNG_READ_BGR_SUPPORTED
-   if (png_ptr->transformations & PNG_BGR)
+   if ((png_ptr->transformations & PNG_BGR) != 0)
      png_do_bgr(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_READ_PACKSWAP_SUPPORTED
-   if (png_ptr->transformations & PNG_PACKSWAP)
+   if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
      png_do_packswap(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_READ_FILLER_SUPPORTED
-   if (png_ptr->transformations & PNG_FILLER)
+   if ((png_ptr->transformations & PNG_FILLER) != 0)
      png_do_read_filler(row_info, png_ptr->row_buf + 1,
          (png_uint_32)png_ptr->filler, png_ptr->flags);
 #endif

 #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
-   if (png_ptr->transformations & PNG_SWAP_ALPHA)
+   if ((png_ptr->transformations & PNG_SWAP_ALPHA) != 0)
      png_do_read_swap_alpha(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_READ_16BIT_SUPPORTED
 #ifdef PNG_READ_SWAP_SUPPORTED
-   if (png_ptr->transformations & PNG_SWAP_BYTES)
+   if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
      png_do_swap(row_info, png_ptr->row_buf + 1);
 #endif
 #endif

 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
-   if (png_ptr->transformations & PNG_USER_TRANSFORM)
-    {
+   if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
+   {
      if (png_ptr->read_user_transform_fn != NULL)
         (*(png_ptr->read_user_transform_fn)) /* User read transform function */
             (png_ptr,     /* png_ptr */
@@ -4973,10 +4976,10 @@ png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
                /*  png_byte pixel_depth;    bits per pixel (depth*channels) */
             png_ptr->row_buf + 1);    /* start of pixel data for row */
 #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
-      if (png_ptr->user_transform_depth)
+      if (png_ptr->user_transform_depth != 0)
         row_info->bit_depth = png_ptr->user_transform_depth;

-      if (png_ptr->user_transform_channels)
+      if (png_ptr->user_transform_channels != 0)
         row_info->channels = png_ptr->user_transform_channels;
 #endif
      row_info->pixel_depth = (png_byte)(row_info->bit_depth *
@@ -4987,5 +4990,5 @@ png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
 #endif
 }

-#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
-#endif /* PNG_READ_SUPPORTED */
+#endif /* READ_TRANSFORMS */
+#endif /* READ */
--- a/pngrutil.c
+++ b/pngrutil.c
--- a/pngset.c
+++ b/pngset.c
@@ -1,7 +1,7 @@

 /* pngset.c - storage of image information into info struct
 *
- * Last changed in libpng 1.6.11 [June 5, 2014]
+ * Last changed in libpng 1.6.15 [November 20, 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*/))
+       2/* override with app values*/) != 0)
      info_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;

   png_colorspace_sync_info(png_ptr, info_ptr);
@@ -90,7 +90,8 @@ 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))
+   if (png_colorspace_set_endpoints(png_ptr, &info_ptr->colorspace,
+       &XYZ, 2) != 0)
      info_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;

   png_colorspace_sync_info(png_ptr, info_ptr);
@@ -129,9 +130,9 @@ 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 /* PNG_FLOATING_POINT_SUPPORTED */
+#  endif /* FLOATING_POINT */

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

 #ifdef PNG_gAMA_SUPPORTED
 void PNGFAPI
@@ -227,13 +228,13 @@ 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)
+   else if ((info_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
      info_ptr->channels = 3;

   else
      info_ptr->channels = 1;

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

   info_ptr->pixel_depth = (png_byte)(info_ptr->channels * info_ptr->bit_depth);
@@ -288,12 +289,14 @@ 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)
   {
@@ -594,7 +597,8 @@ 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))
+   if (png_colorspace_set_sRGB(png_ptr, &info_ptr->colorspace,
+       srgb_intent) != 0)
   {
      /* This causes the gAMA and cHRM to be written too */
      info_ptr->colorspace.flags |=
@@ -661,6 +665,7 @@ 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;
@@ -890,7 +895,7 @@ 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))
+       (png_ptr->mode & PNG_WROTE_tIME) != 0)
      return;

   if (mod_time->month == 0   || mod_time->month > 12  ||
@@ -1041,6 +1046,7 @@ png_set_sPLT(png_const_structrp png_ptr,
      if (np->entries == NULL)
      {
         png_free(png_ptr, np->name);
+         np->name = NULL;
         break;
      }

@@ -1063,7 +1069,7 @@ png_set_sPLT(png_const_structrp png_ptr,
   if (nentries > 0)
      png_chunk_report(png_ptr, "sPLT out of memory", PNG_CHUNK_WRITE_ERROR);
 }
-#endif /* PNG_sPLT_SUPPORTED */
+#endif /* sPLT */

 #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
 static png_byte
@@ -1075,7 +1081,7 @@ check_location(png_const_structrp png_ptr, int location)
    * 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))
+   if (location == 0 && (png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
   {
      /* Write struct, so unknown chunks come from the app */
      png_app_warning(png_ptr,
@@ -1121,7 +1127,7 @@ png_set_unknown_chunks(png_const_structrp png_ptr,
    */
 #  if !defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) && \
      defined(PNG_READ_SUPPORTED)
-      if (png_ptr->mode & PNG_IS_READ_STRUCT)
+      if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
      {
         png_app_error(png_ptr, "no unknown chunk support on read");
         return;
@@ -1129,7 +1135,7 @@ png_set_unknown_chunks(png_const_structrp png_ptr,
 #  endif
 #  if !defined(PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED) && \
      defined(PNG_WRITE_SUPPORTED)
-      if (!(png_ptr->mode & PNG_IS_READ_STRUCT))
+      if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
      {
         png_app_error(png_ptr, "no unknown chunk support on write");
         return;
@@ -1215,7 +1221,7 @@ 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)) /* undocumented! */
+         if ((location & PNG_HAVE_IDAT) != 0) /* undocumented! */
            location = PNG_AFTER_IDAT;

         else
@@ -1253,10 +1259,13 @@ 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) if (memcmp(list, add, 4) == 0)
+   for (i=0; i<count; ++i, list += 5)
   {
-      list[4] = (png_byte)keep;
-      return count;
+      if (memcmp(list, add, 4) == 0)
+      {
+         list[4] = (png_byte)keep;
+         return count;
+      }
   }

   if (keep != PNG_HANDLE_CHUNK_AS_DEFAULT)
@@ -1320,7 +1329,7 @@ png_set_keep_unknown_chunks(png_structrp png_ptr, int keep,
      };

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

   else /* num_chunks_in > 0 */
@@ -1380,12 +1389,15 @@ 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)
@@ -1393,6 +1405,7 @@ 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)
@@ -1444,7 +1457,8 @@ 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 && (info_ptr->row_pointers != row_pointers))
+   if (info_ptr->row_pointers != NULL &&
+       (info_ptr->row_pointers != row_pointers))
      png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);

   info_ptr->row_pointers = row_pointers;
@@ -1464,7 +1478,7 @@ 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)
+      if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
      {
         png_ptr->IDAT_read_size = (png_uint_32)size; /* checked above */
         return;
@@ -1472,7 +1486,7 @@ 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))
+      if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
      {
         if (png_ptr->zowner != 0)
         {
@@ -1510,7 +1524,7 @@ 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 && info_ptr)
+   if (png_ptr != NULL && info_ptr != NULL)
      info_ptr->valid &= ~mask;
 }

@@ -1548,7 +1562,7 @@ png_set_chunk_malloc_max (png_structrp png_ptr,
   if (png_ptr != NULL)
      png_ptr->user_chunk_malloc_max = user_chunk_malloc_max;
 }
-#endif /* ?PNG_SET_USER_LIMITS_SUPPORTED */
+#endif /* ?SET_USER_LIMITS */


 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
@@ -1571,14 +1585,14 @@ 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 /* PNG_BENIGN_ERRORS_SUPPORTED */
+#endif /* BENIGN_ERRORS */

 #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 zeroes
+    * from this gracefully by filling any incomplete palette with zeros
    * (opaque black).  By default, when this occurs libpng will issue
    * a benign error.  This API can be used to override that behavior.
    */
@@ -1594,4 +1608,4 @@ png_set_check_for_invalid_index(png_structrp png_ptr, int allowed)
      png_ptr->num_palette_max = -1;
 }
 #endif
-#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
+#endif /* READ || WRITE */
--- a/pngstruct.h
+++ b/pngstruct.h
@@ -274,7 +274,7 @@ struct png_struct_def
 #ifdef PNG_READ_GAMMA_SUPPORTED
   png_color_16 background_1; /* background normalized to gamma 1.0 */
 #endif
-#endif /* PNG_bKGD_SUPPORTED */
+#endif /* bKGD */

 #ifdef PNG_WRITE_FLUSH_SUPPORTED
   png_flush_ptr output_flush_fn; /* Function for flushing output */
@@ -331,7 +331,7 @@ struct png_struct_def
   int process_mode;                 /* what push library is currently doing */
   int cur_palette;                  /* current push library palette index */

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

 #if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
 /* For the Borland special 64K segment handler */
--- a/pngtest.c
+++ b/pngtest.c
@@ -1,7 +1,7 @@

 /* pngtest.c - a simple test program to test libpng
 *
- * Last changed in libpng 1.6.11 [June 5, 2014]
+ * Last changed in libpng 1.6.15 [November 20, 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.)
@@ -283,7 +283,8 @@ 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++)
       {
@@ -310,7 +311,7 @@ count_zero_samples(png_structp png_ptr, png_row_infop row_info, png_bytep data)
       }
    }
 }
-#endif /* PNG_WRITE_USER_TRANSFORM_SUPPORTED */
+#endif /* WRITE_USER_TRANSFORM */

 #ifndef PNG_STDIO_SUPPORTED
 /* START of code to validate stdio-free compilation */
@@ -419,7 +420,7 @@ 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 /* !PNG_STDIO_SUPPORTED */
+#endif /* !STDIO */

 /* 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
@@ -588,7 +589,7 @@ png_debug_free(png_structp png_ptr, png_voidp ptr)

         if (pinfo->next == NULL)
         {
-            fprintf(STDERR, "Pointer %x not found\n", (unsigned int)ptr);
+            fprintf(STDERR, "Pointer %p not found\n", ptr);
            break;
         }

@@ -604,7 +605,7 @@ png_debug_free(png_structp png_ptr, png_voidp ptr)
      free(ptr);
   ptr = NULL;
 }
-#endif /* PNG_USER_MEM_SUPPORTED && PNG_DEBUG */
+#endif /* USER_MEM && DEBUG */
 /* END of code to test memory allocation/deallocation */


@@ -643,16 +644,16 @@ set_location(png_structp png_ptr, struct user_chunk_data *data, int what)
 {
   int location;

-   if ((data->location[0] & what) || (data->location[1] & what))
+   if ((data->location[0] & what) != 0 || (data->location[1] & what) != 0)
      return 0; /* already have one of these */

-   /* Find where we are (the code below zeros info_ptr to indicate that the
+   /* Find where we are (the code below zeroes 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))
+   else if (png_get_valid(png_ptr, data->info_ptr, PNG_INFO_PLTE) != 0)
      location = what | before_IDAT;

   else
@@ -699,7 +700,7 @@ 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))
+         if (set_location(png_ptr, my_user_chunk_data, have_sTER) != 0)
         {
            my_user_chunk_data->sTER_mode=chunk->data[0];
            return (1);
@@ -718,7 +719,7 @@ 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))
+   if (set_location(png_ptr, my_user_chunk_data, have_vpAg) == 0)
      return (0);  /* duplicate vpAg */

   my_user_chunk_data->vpAg_width = png_get_uint_31(png_ptr, chunk->data);
@@ -779,8 +780,8 @@ write_chunks(png_structp write_ptr, int location)
         write_vpAg_chunk(write_ptr);
   }
 }
-#endif /* PNG_WRITE_SUPPORTED */
-#else /* !PNG_READ_USER_CHUNKS_SUPPORTED */
+#endif /* WRITE */
+#else /* !READ_USER_CHUNKS */
 #  define write_chunks(pp,loc) ((void)0)
 #endif
 /* END of code to demonstrate user chunk support */
@@ -1049,7 +1050,7 @@ 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))
+          &color_type, &interlace_type, &compression_type, &filter_type) != 0)
      {
         png_set_IHDR(write_ptr, write_info_ptr, width, height, bit_depth,
            color_type, interlace_type, compression_type, filter_type);
@@ -1082,7 +1083,7 @@ 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))
+         &red_x, &red_y, &green_x, &green_y, &blue_x, &blue_y) != 0)
      {
         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);
@@ -1093,7 +1094,7 @@ 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))
+      if (png_get_gAMA_fixed(read_ptr, read_info_ptr, &gamma) != 0)
         png_set_gAMA_fixed(write_ptr, write_info_ptr, gamma);
   }
 #endif
@@ -1105,7 +1106,7 @@ 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))
+         &red_y, &green_x, &green_y, &blue_x, &blue_y) != 0)
      {
         png_set_cHRM(write_ptr, write_info_ptr, white_x, white_y, red_x,
            red_y, green_x, green_y, blue_x, blue_y);
@@ -1116,7 +1117,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
   {
      double gamma;

-      if (png_get_gAMA(read_ptr, read_info_ptr, &gamma))
+      if (png_get_gAMA(read_ptr, read_info_ptr, &gamma) != 0)
         png_set_gAMA(write_ptr, write_info_ptr, gamma);
   }
 #endif
@@ -1130,7 +1131,7 @@ 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))
+                      &profile, &proflen) != 0)
      {
         png_set_iCCP(write_ptr, write_info_ptr, name, compression_type,
                      profile, proflen);
@@ -1141,7 +1142,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
   {
      int intent;

-      if (png_get_sRGB(read_ptr, read_info_ptr, &intent))
+      if (png_get_sRGB(read_ptr, read_info_ptr, &intent) != 0)
         png_set_sRGB(write_ptr, write_info_ptr, intent);
   }
 #endif
@@ -1149,14 +1150,14 @@ 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))
+      if (png_get_PLTE(read_ptr, read_info_ptr, &palette, &num_palette) != 0)
         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))
+      if (png_get_bKGD(read_ptr, read_info_ptr, &background) != 0)
      {
         png_set_bKGD(write_ptr, write_info_ptr, background);
      }
@@ -1166,7 +1167,7 @@ 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))
+      if (png_get_hIST(read_ptr, read_info_ptr, &hist) != 0)
         png_set_hIST(write_ptr, write_info_ptr, hist);
   }
 #endif
@@ -1176,7 +1177,7 @@ 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))
+          &unit_type) != 0)
      {
         png_set_oFFs(write_ptr, write_info_ptr, offset_x, offset_y, unit_type);
      }
@@ -1190,7 +1191,7 @@ 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))
+         &nparams, &units, &params) != 0)
      {
         png_set_pCAL(write_ptr, write_info_ptr, purpose, X0, X1, type,
            nparams, units, params);
@@ -1202,7 +1203,8 @@ 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))
+      if (png_get_pHYs(read_ptr, read_info_ptr, &res_x, &res_y,
+          &unit_type) != 0)
         png_set_pHYs(write_ptr, write_info_ptr, res_x, res_y, unit_type);
   }
 #endif
@@ -1210,7 +1212,7 @@ 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))
+      if (png_get_sBIT(read_ptr, read_info_ptr, &sig_bit) != 0)
         png_set_sBIT(write_ptr, write_info_ptr, sig_bit);
   }
 #endif
@@ -1222,7 +1224,7 @@ 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))
+         &scal_height) != 0)
      {
         png_set_sCAL(write_ptr, write_info_ptr, unit, scal_width, scal_height);
      }
@@ -1234,7 +1236,7 @@ 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))
+          &scal_height) != 0)
      {
         png_set_sCAL_s(write_ptr, write_info_ptr, unit, scal_width,
             scal_height);
@@ -1274,11 +1276,11 @@ 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))
+      if (png_get_tIME(read_ptr, read_info_ptr, &mod_time) != 0)
      {
         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))
+         if (png_convert_to_rfc1123_buffer(tIME_string, mod_time) != 0)
            tIME_string[(sizeof tIME_string) - 1] = '\0';

         else
@@ -1288,7 +1290,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
         }

         tIME_chunk_present++;
-#endif /* PNG_TIME_RFC1123_SUPPORTED */
+#endif /* TIME_RFC1123 */
      }
   }
 #endif
@@ -1299,7 +1301,7 @@ 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))
+         &trans_color) != 0)
      {
         int sample_max = (1 << bit_depth);
         /* libpng doesn't reject a tRNS chunk with out-of-range samples */
@@ -1382,11 +1384,12 @@ 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 (%u bytes)", (unsigned long)row_buf,
-            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));

 #endif /* !SINGLE_ROWBUF_ALLOC */
         png_read_rows(read_ptr, (png_bytepp)&row_buf, NULL, 1);
@@ -1403,7 +1406,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
         t_encode += (t_stop - t_start);
         t_start = t_stop;
 #endif
-#endif /* PNG_WRITE_SUPPORTED */
+#endif /* WRITE */

 #ifndef SINGLE_ROWBUF_ALLOC
         pngtest_debug2("Freeing row buffer (pass %d, y = %u)", pass, y);
@@ -1456,11 +1459,11 @@ 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))
+      if (png_get_tIME(read_ptr, end_info_ptr, &mod_time) != 0)
      {
         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))
+         if (png_convert_to_rfc1123_buffer(tIME_string, mod_time) != 0)
            tIME_string[(sizeof tIME_string) - 1] = '\0';

         else
@@ -1470,7 +1473,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
         }

         tIME_chunk_present++;
-#endif /* PNG_TIME_RFC1123_SUPPORTED */
+#endif /* TIME_RFC1123 */
      }
   }
 #endif
@@ -1675,7 +1678,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
         }
      }
   }
-#endif /* PNG_WRITE_SUPPORTED */
+#endif /* WRITE */

   FCLOSE(fpin);
   FCLOSE(fpout);
@@ -1780,10 +1783,11 @@ main(int argc, char *argv[])
      }
   }

-   if (!multiple && argc == 3 + verbose)
+   if (multiple == 0 && argc == 3 + verbose)
     outname = argv[2 + verbose];

-   if ((!multiple && argc > 3 + verbose) || (multiple && argc < 2))
+   if ((multiple == 0 && argc > 3 + verbose) ||
+       (multiple != 0 && argc < 2))
   {
     fprintf(STDERR,
       "usage: %s [infile.png] [outfile.png]\n\t%s -m {infile.png}\n",
@@ -1805,6 +1809,9 @@ 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)
         {
@@ -1819,7 +1826,7 @@ main(int argc, char *argv[])
 #endif
 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
            for (k = 0; k<256; k++)
-               if (filters_used[k])
+               if (filters_used[k] != 0)
                  fprintf(STDERR, " Filter %d was used %lu times\n",
                     k, (unsigned long)filters_used[k]);
 #endif
@@ -1828,7 +1835,7 @@ main(int argc, char *argv[])
            fprintf(STDERR, " tIME = %s\n", tIME_string);

         tIME_chunk_present = 0;
-#endif /* PNG_TIME_RFC1123_SUPPORTED */
+#endif /* TIME_RFC1123 */
         }

         else
@@ -1850,9 +1857,9 @@ main(int argc, char *argv[])

            while (pinfo != NULL)
            {
-               fprintf(STDERR, " %lu bytes at %x\n",
+               fprintf(STDERR, " %lu bytes at %p\n",
                 (unsigned long)pinfo->size,
-                 (unsigned int)pinfo->pointer);
+                 pinfo->pointer);
               pinfo = pinfo->next;
            }
         }
@@ -1886,7 +1893,12 @@ 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);

@@ -1905,21 +1917,26 @@ main(int argc, char *argv[])
 #endif
 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
                for (k = 0; k<256; k++)
-                   if (filters_used[k])
+                   if (filters_used[k] != 0)
                      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 /* PNG_TIME_RFC1123_SUPPORTED */
+#endif /* TIME_RFC1123 */
            }
         }

         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;
@@ -1938,8 +1955,8 @@ main(int argc, char *argv[])

             while (pinfo != NULL)
             {
-                fprintf(STDERR, " %lu bytes at %x\n",
-                   (unsigned long)pinfo->size, (unsigned int)pinfo->pointer);
+                fprintf(STDERR, " %lu bytes at %p\n",
+                   (unsigned long)pinfo->size, pinfo->pointer);
                pinfo = pinfo->next;
             }
          }
@@ -1991,4 +2008,4 @@ main(void)
 #endif

 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef png_libpng_version_1_6_14beta06 Your_png_h_is_not_version_1_6_14beta06;
+typedef png_libpng_version_1_6_16 Your_png_h_is_not_version_1_6_16;
--- 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 1.6.11 [June 5, 2014]
+ * Last changed in libpng 1.6.15 [November 20, 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 && png_ptr->interlaced)
+   if (png_ptr != 0 && png_ptr->interlaced != 0)
   {
      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)
+   if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
   {
 #     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)
+   if ((png_ptr->transformations & PNG_FILLER) != 0)
      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 /* PNG_READ_PACKSWAP_SUPPORTED or PNG_WRITE_PACKSWAP_SUPPORTED */
+#endif /* PACKSWAP || WRITE_PACKSWAP */

 #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))
+   if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
   {
      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 /* PNG_READ_BGR_SUPPORTED or PNG_WRITE_BGR_SUPPORTED */
+#endif /* READ_BGR || WRITE_BGR */

 #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 /* PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED */
+#endif /* CHECK_FOR_INVALID_INDEX */

 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
@@ -844,7 +844,6 @@ png_get_current_pass_number(png_const_structrp png_ptr)
      return png_ptr->pass;
   return 8; /* invalid */
 }
-#endif /* PNG_USER_TRANSFORM_INFO_SUPPORTED */
-#endif /* PNG_READ_USER_TRANSFORM_SUPPORTED ||
-          PNG_WRITE_USER_TRANSFORM_SUPPORTED */
-#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
+#endif /* USER_TRANSFORM_INFO */
+#endif /* READ_USER_TRANSFORM || WRITE_USER_TRANSFORM */
+#endif /* READ || WRITE */
--- a/pngwio.c
+++ b/pngwio.c
@@ -1,7 +1,7 @@

 /* pngwio.c - functions for data output
 *
- * Last changed in libpng 1.6.9 [February 6, 2014]
+ * Last changed in libpng 1.6.15 [November 20, 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 /* PNG_WRITE_FLUSH_SUPPORTED */
+#endif /* WRITE_FLUSH */

 #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 /* PNG_WRITE_SUPPORTED */
+#endif /* WRITE */
--- a/pngwrite.c
+++ b/pngwrite.c
@@ -1,7 +1,7 @@

 /* pngwrite.c - general routines to write a PNG file
 *
- * Last changed in libpng 1.6.14 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.15 [November 20, 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)
+   if (info_ptr->unknown_chunks_num != 0)
   {
      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)
+         if ((up->location & where) != 0)
      {
         /* 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 /* PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED */
+#endif /* WRITE_UNKNOWN_CHUNKS */

 /* 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))
+   if ((png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE) == 0)
   {
   /* Write PNG signature */
   png_write_sig(png_ptr);

 #ifdef PNG_MNG_FEATURES_SUPPORTED
-   if ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) && \
-       (png_ptr->mng_features_permitted))
+   if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) != 0 && \
+       png_ptr->mng_features_permitted != 0)
   {
      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) &&
-         (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_gAMA) &&
-         (info_ptr->valid & PNG_INFO_gAMA))
+      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)
         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) &&
-         (info_ptr->valid & PNG_INFO_iCCP))
+      if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
+          (info_ptr->valid & PNG_INFO_iCCP) != 0)
      {
 #        ifdef PNG_WRITE_sRGB_SUPPORTED
-            if (info_ptr->valid & PNG_INFO_sRGB)
+            if ((info_ptr->valid & PNG_INFO_sRGB) != 0)
               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) &&
-         (info_ptr->valid & PNG_INFO_sRGB))
+      if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
+          (info_ptr->valid & PNG_INFO_sRGB) != 0)
         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)
+   if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
      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) &&
-         (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) &&
-         (info_ptr->valid & PNG_INFO_cHRM))
+      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)
         png_write_cHRM_fixed(png_ptr, &info_ptr->colorspace.end_points_xy);
 #  endif
 #endif
@@ -201,19 +201,19 @@ 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)
+   if ((info_ptr->valid & PNG_INFO_PLTE) != 0)
      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)
+   else if ((info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) !=0)
      png_error(png_ptr, "Valid palette required for paletted images");

 #ifdef PNG_WRITE_tRNS_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_tRNS)
+   if ((info_ptr->valid & PNG_INFO_tRNS) !=0)
   {
 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
      /* Invert the alpha channel (in tRNS) */
-      if ((png_ptr->transformations & PNG_INVERT_ALPHA) &&
+      if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0 &&
          info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
      {
         int j;
@@ -227,42 +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)
+   if ((info_ptr->valid & PNG_INFO_bKGD) != 0)
      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)
+   if ((info_ptr->valid & PNG_INFO_hIST) != 0)
      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)
+   if ((info_ptr->valid & PNG_INFO_oFFs) != 0)
      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)
+   if ((info_ptr->valid & PNG_INFO_pCAL) != 0)
      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)
+   if ((info_ptr->valid & PNG_INFO_sCAL) != 0)
      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)
+   if ((info_ptr->valid & PNG_INFO_pHYs) != 0)
      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)
+   if ((info_ptr->valid & PNG_INFO_tIME) != 0)
   {
      png_write_tIME(png_ptr, &(info_ptr->mod_time));
      png_ptr->mode |= PNG_WROTE_tIME;
@@ -270,7 +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)
+   if ((info_ptr->valid & PNG_INFO_sPLT) != 0)
      for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
         png_write_sPLT(png_ptr, info_ptr->splt_palettes + i);
 #endif /* sPLT */
@@ -292,11 +292,14 @@ 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 */
@@ -306,11 +309,11 @@ png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)
         /* 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;
 #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)
@@ -348,7 +351,7 @@ png_write_end(png_structrp png_ptr, png_inforp info_ptr)
   if (png_ptr == NULL)
      return;

-   if (!(png_ptr->mode & PNG_HAVE_IDAT))
+   if ((png_ptr->mode & PNG_HAVE_IDAT) == 0)
      png_error(png_ptr, "No IDATs written into file");

 #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
@@ -364,8 +367,8 @@ 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) &&
-          !(png_ptr->mode & PNG_WROTE_tIME))
+      if ((info_ptr->valid & PNG_INFO_tIME) != 0 &&
+          (png_ptr->mode & PNG_WROTE_tIME) == 0)
         png_write_tIME(png_ptr, &(info_ptr->mod_time));

 #endif
@@ -386,11 +389,14 @@ 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)
@@ -399,11 +405,11 @@ png_write_end(png_structrp png_ptr, png_inforp info_ptr)
            /* 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;
 #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)
@@ -412,12 +418,11 @@ 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
@@ -492,7 +497,7 @@ png_create_write_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
 {
   png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
       error_fn, warn_fn, mem_ptr, malloc_fn, free_fn);
-#endif /* PNG_USER_MEM_SUPPORTED */
+#endif /* USER_MEM */
   if (png_ptr != NULL)
   {
      /* Set the zlib control values to defaults; they can be overridden by the
@@ -516,7 +521,7 @@ 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 /* PNG_WRITE_COMPRESSED_TEXT_SUPPORTED */
+#endif /* WRITE_COMPRESSED_TEXT */

      /* This is a highly dubious configuration option; by default it is off,
       * but it may be appropriate for private builds that are testing
@@ -613,7 +618,7 @@ 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))
+   if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
   {
      int bytes_per_pixel;
      png_uint_32 row_width = row_info->width;
@@ -666,10 +671,10 @@ png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
            *(rp + 5) = (png_byte)(blue & 0xff);
         }
      }
-#endif /* PNG_WRITE_16BIT_SUPPORTED */
+#endif /* WRITE_16BIT */
   }
 }
-#endif /* PNG_MNG_FEATURES_SUPPORTED */
+#endif /* MNG_FEATURES */

 /* Called by user to write a row of image data */
 void PNGAPI
@@ -688,44 +693,44 @@ 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))
+      if ((png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE) == 0)
         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)
+      if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
         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)
+      if ((png_ptr->transformations & PNG_FILLER) != 0)
         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)
+      if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
         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)
+      if ((png_ptr->transformations & PNG_PACK) != 0)
         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)
+      if ((png_ptr->transformations & PNG_SHIFT) != 0)
         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)
+      if ((png_ptr->transformations & PNG_BGR) != 0)
         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)
+      if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
         png_warning(png_ptr, "PNG_WRITE_SWAP_SUPPORTED is not defined");
 #endif

@@ -734,12 +739,13 @@ 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 && (png_ptr->transformations & PNG_INTERLACE))
+   if (png_ptr->interlaced != 0 &&
+       (png_ptr->transformations & PNG_INTERLACE) != 0)
   {
      switch (png_ptr->pass)
      {
         case 0:
-            if (png_ptr->row_number & 0x07)
+            if ((png_ptr->row_number & 0x07) != 0)
            {
               png_write_finish_row(png_ptr);
               return;
@@ -747,7 +753,7 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)
            break;

         case 1:
-            if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
+            if ((png_ptr->row_number & 0x07) != 0 || png_ptr->width < 5)
            {
               png_write_finish_row(png_ptr);
               return;
@@ -763,7 +769,7 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)
            break;

         case 3:
-            if ((png_ptr->row_number & 0x03) || png_ptr->width < 3)
+            if ((png_ptr->row_number & 0x03) != 0 || png_ptr->width < 3)
            {
               png_write_finish_row(png_ptr);
               return;
@@ -779,7 +785,7 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)
            break;

         case 5:
-            if ((png_ptr->row_number & 0x01) || png_ptr->width < 2)
+            if ((png_ptr->row_number & 0x01) != 0 || png_ptr->width < 2)
            {
               png_write_finish_row(png_ptr);
               return;
@@ -787,7 +793,7 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)
            break;

         case 6:
-            if (!(png_ptr->row_number & 0x01))
+            if ((png_ptr->row_number & 0x01) == 0)
            {
               png_write_finish_row(png_ptr);
               return;
@@ -821,7 +827,7 @@ 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))
+       (png_ptr->transformations & PNG_INTERLACE) != 0)
   {
      png_do_write_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass);
      /* This should always get caught above, but still ... */
@@ -835,7 +841,7 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)

 #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
   /* Handle other transformations */
-   if (png_ptr->transformations)
+   if (png_ptr->transformations != 0)
      png_do_write_transformations(png_ptr, &row_info);
 #endif

@@ -856,7 +862,7 @@ 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) &&
+   if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
       (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
   {
      /* Intrapixel differencing */
@@ -909,7 +915,7 @@ png_write_flush(png_structrp png_ptr)
   png_ptr->flush_rows = 0;
   png_flush(png_ptr);
 }
-#endif /* PNG_WRITE_FLUSH_SUPPORTED */
+#endif /* WRITE_FLUSH */

 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
 static void png_reset_filter_heuristics(png_structrp png_ptr);/* forward decl */
@@ -922,18 +928,24 @@ 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)
+   if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
      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->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);
+   png_ptr->prev_row = NULL;
+   png_ptr->sub_row = NULL;
+   png_ptr->up_row = NULL;
+   png_ptr->avg_row = NULL;
+   png_ptr->paeth_row = NULL;
 #endif

 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
@@ -941,10 +953,13 @@ 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
@@ -990,7 +1005,7 @@ 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) &&
+   if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
       (method == PNG_INTRAPIXEL_DIFFERENCING))
      method = PNG_FILTER_TYPE_BASE;

@@ -1004,7 +1019,7 @@ png_set_filter(png_structrp png_ptr, int method, int filters)
         case 6:
         case 7: png_app_error(png_ptr, "Unknown row filter for method 0");
            /* FALL THROUGH */
-#endif /* PNG_WRITE_FILTER_SUPPORTED */
+#endif /* WRITE_FILTER */
         case PNG_FILTER_VALUE_NONE:
            png_ptr->do_filter = PNG_FILTER_NONE; break;

@@ -1026,7 +1041,7 @@ png_set_filter(png_structrp png_ptr, int method, int filters)
 #else
         default:
            png_app_error(png_ptr, "Unknown row filter for method 0");
-#endif /* PNG_WRITE_FILTER_SUPPORTED */
+#endif /* WRITE_FILTER */
      }

      /* If we have allocated the row_buf, this means we have already started
@@ -1041,14 +1056,16 @@ png_set_filter(png_structrp png_ptr, int method, int filters)
      if (png_ptr->row_buf != NULL)
      {
 #ifdef PNG_WRITE_FILTER_SUPPORTED
-         if ((png_ptr->do_filter & PNG_FILTER_SUB) && png_ptr->sub_row == NULL)
+         if ((png_ptr->do_filter & PNG_FILTER_SUB) != 0 &&
+             png_ptr->sub_row == NULL)
         {
            png_ptr->sub_row = (png_bytep)png_malloc(png_ptr,
                (png_ptr->rowbytes + 1));
            png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;
         }

-         if ((png_ptr->do_filter & PNG_FILTER_UP) && png_ptr->up_row == NULL)
+         if ((png_ptr->do_filter & PNG_FILTER_UP) != 0 &&
+              png_ptr->up_row == NULL)
         {
            if (png_ptr->prev_row == NULL)
            {
@@ -1065,7 +1082,8 @@ png_set_filter(png_structrp png_ptr, int method, int filters)
            }
         }

-         if ((png_ptr->do_filter & PNG_FILTER_AVG) && png_ptr->avg_row == NULL)
+         if ((png_ptr->do_filter & PNG_FILTER_AVG) != 0 &&
+              png_ptr->avg_row == NULL)
         {
            if (png_ptr->prev_row == NULL)
            {
@@ -1082,7 +1100,7 @@ png_set_filter(png_structrp png_ptr, int method, int filters)
            }
         }

-         if ((png_ptr->do_filter & PNG_FILTER_PAETH) &&
+         if ((png_ptr->do_filter & PNG_FILTER_PAETH) != 0 &&
             png_ptr->paeth_row == NULL)
         {
            if (png_ptr->prev_row == NULL)
@@ -1100,7 +1118,7 @@ png_set_filter(png_structrp png_ptr, int method, int filters)
         }

         if (png_ptr->do_filter == PNG_NO_FILTERS)
-#endif /* PNG_WRITE_FILTER_SUPPORTED */
+#endif /* WRITE_FILTER */
            png_ptr->do_filter = PNG_FILTER_NONE;
      }
   }
@@ -1243,7 +1261,7 @@ 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))
+   if (png_init_filter_heuristics(png_ptr, heuristic_method, num_weights) == 0)
      return;

   /* If using the weighted method copy in the weights. */
@@ -1298,7 +1316,7 @@ 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))
+   if (png_init_filter_heuristics(png_ptr, heuristic_method, num_weights) == 0)
      return;

   /* If using the weighted method copy in the weights. */
@@ -1352,7 +1370,7 @@ png_set_filter_heuristics_fixed(png_structrp png_ptr, int heuristic_method,
   }
 }
 #endif /* FIXED_POINT */
-#endif /* PNG_WRITE_WEIGHTED_FILTER_SUPPORTED */
+#endif /* WRITE_WEIGHTED_FILTER */

 void PNGAPI
 png_set_compression_level(png_structrp png_ptr, int level)
@@ -1509,7 +1527,7 @@ png_set_text_compression_method(png_structrp png_ptr, int method)

   png_ptr->zlib_text_method = method;
 }
-#endif /* PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED */
+#endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
 /* end of API added to libpng-1.5.4 */

 void PNGAPI
@@ -1557,7 +1575,7 @@ 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)
+   if ((transforms & PNG_TRANSFORM_INVERT_MONO) != 0)
 #ifdef PNG_WRITE_INVERT_SUPPORTED
      png_set_invert_mono(png_ptr);
 #else
@@ -1567,16 +1585,16 @@ 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)
+   if ((transforms & PNG_TRANSFORM_SHIFT) != 0)
 #ifdef PNG_WRITE_SHIFT_SUPPORTED
-      if (info_ptr->valid & PNG_INFO_sBIT)
+      if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
         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)
+   if ((transforms & PNG_TRANSFORM_PACKING) != 0)
 #ifdef PNG_WRITE_PACK_SUPPORTED
      png_set_packing(png_ptr);
 #else
@@ -1584,7 +1602,7 @@ 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)
+   if ((transforms & PNG_TRANSFORM_SWAP_ALPHA) != 0)
 #ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
      png_set_swap_alpha(png_ptr);
 #else
@@ -1595,13 +1613,13 @@ 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))
+   if ((transforms & (PNG_TRANSFORM_STRIP_FILLER_AFTER|
+      PNG_TRANSFORM_STRIP_FILLER_BEFORE)) != 0)
   {
 #ifdef PNG_WRITE_FILLER_SUPPORTED
-      if (transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER)
+      if ((transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER) != 0)
      {
-         if (transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE)
+         if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
            png_app_error(png_ptr,
               "PNG_TRANSFORM_STRIP_FILLER: BEFORE+AFTER not supported");

@@ -1609,7 +1627,7 @@ 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)
+      else if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
         png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
 #else
      png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_FILLER not supported");
@@ -1617,7 +1635,7 @@ png_write_png(png_structrp png_ptr, png_inforp info_ptr,
   }

   /* Flip BGR pixels to RGB */
-   if (transforms & PNG_TRANSFORM_BGR)
+   if ((transforms & PNG_TRANSFORM_BGR) != 0)
 #ifdef PNG_WRITE_BGR_SUPPORTED
      png_set_bgr(png_ptr);
 #else
@@ -1625,7 +1643,7 @@ 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)
+   if ((transforms & PNG_TRANSFORM_SWAP_ENDIAN) != 0)
 #ifdef PNG_WRITE_SWAP_SUPPORTED
      png_set_swap(png_ptr);
 #else
@@ -1633,7 +1651,7 @@ 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)
+   if ((transforms & PNG_TRANSFORM_PACKSWAP) != 0)
 #ifdef PNG_WRITE_PACKSWAP_SUPPORTED
      png_set_packswap(png_ptr);
 #else
@@ -1641,7 +1659,7 @@ 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)
+   if ((transforms & PNG_TRANSFORM_INVERT_ALPHA) != 0)
 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
      png_set_invert_alpha(png_ptr);
 #else
@@ -1732,14 +1750,14 @@ png_write_image_16bit(png_voidp argument)
      display->first_row);
   png_uint_16p output_row = png_voidcast(png_uint_16p, display->local_row);
   png_uint_16p row_end;
-   const int channels = (image->format & PNG_FORMAT_FLAG_COLOR) ? 3 : 1;
+   const int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ? 3 : 1;
   int aindex = 0;
   png_uint_32 y = image->height;

-   if (image->format & PNG_FORMAT_FLAG_ALPHA)
+   if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
   {
 #     ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
-         if (image->format & PNG_FORMAT_FLAG_AFIRST)
+         if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
         {
            aindex = -1;
            ++input_row; /* To point to the first component */
@@ -1889,15 +1907,15 @@ png_write_image_8bit(png_voidp argument)
      display->first_row);
   png_bytep output_row = png_voidcast(png_bytep, display->local_row);
   png_uint_32 y = image->height;
-   const int channels = (image->format & PNG_FORMAT_FLAG_COLOR) ? 3 : 1;
+   const int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ? 3 : 1;

-   if (image->format & PNG_FORMAT_FLAG_ALPHA)
+   if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
   {
      png_bytep row_end;
      int aindex;

 #     ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
-         if (image->format & PNG_FORMAT_FLAG_AFIRST)
+         if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
         {
            aindex = -1;
            ++input_row; /* To point to the first component */
@@ -1994,7 +2012,7 @@ png_image_set_PLTE(png_image_write_control *display)
 #  endif

 #  ifdef PNG_FORMAT_BGR_SUPPORTED
-      const int bgr = (format & PNG_FORMAT_FLAG_BGR) ? 2 : 0;
+      const int bgr = (format & PNG_FORMAT_FLAG_BGR) != 0 ? 2 : 0;
 #  else
 #     define bgr 0
 #  endif
@@ -2011,13 +2029,13 @@ 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)
+      if ((format & PNG_FORMAT_FLAG_LINEAR) != 0)
      {
         png_const_uint_16p entry = png_voidcast(png_const_uint_16p, cmap);

         entry += i * channels;

-         if (channels & 1) /* no alpha */
+         if ((channels & 1) != 0) /* no alpha */
         {
            if (channels >= 3) /* RGB */
            {
@@ -2129,10 +2147,11 @@ png_image_write_main(png_voidp argument)
   png_inforp info_ptr = image->opaque->info_ptr;
   png_uint_32 format = image->format;

-   int colormap = (format & PNG_FORMAT_FLAG_COLORMAP) != 0;
-   int linear = !colormap && (format & PNG_FORMAT_FLAG_LINEAR) != 0; /* input */
-   int alpha = !colormap && (format & PNG_FORMAT_FLAG_ALPHA) != 0;
-   int write_16bit = linear && !colormap && !display->convert_to_8bit;
+   /* The following four ints are actually booleans */
+   int colormap = (format & PNG_FORMAT_FLAG_COLORMAP);
+   int linear = !colormap && (format & PNG_FORMAT_FLAG_LINEAR); /* input */
+   int alpha = !colormap && (format & PNG_FORMAT_FLAG_ALPHA);
+   int write_16bit = linear && !colormap && (display->convert_to_8bit == 0);

 #  ifdef PNG_BENIGN_ERRORS_SUPPORTED
      /* Make sure we error out on any bad situation */
@@ -2144,7 +2163,7 @@ 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)
+   if ((format & PNG_FORMAT_FLAG_COLORMAP) != 0)
   {
      if (display->colormap != NULL && image->colormap_entries > 0)
      {
@@ -2181,7 +2200,7 @@ 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))
+      if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0)
         png_set_cHRM_fixed(png_ptr, info_ptr,
            /* color      x       y */
            /* white */ 31270, 32900,
@@ -2191,7 +2210,7 @@ png_image_write_main(png_voidp argument)
         );
   }

-   else if (!(image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB))
+   else if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0)
      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
@@ -2212,23 +2231,23 @@ png_image_write_main(png_voidp argument)
   {
      PNG_CONST png_uint_16 le = 0x0001;

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

 #  ifdef PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED
-      if (format & PNG_FORMAT_FLAG_BGR)
+      if ((format & PNG_FORMAT_FLAG_BGR) != 0)
      {
-         if (!colormap && (format & PNG_FORMAT_FLAG_COLOR) != 0)
+         if (colormap == 0 && (format & PNG_FORMAT_FLAG_COLOR) != 0)
            png_set_bgr(png_ptr);
         format &= ~PNG_FORMAT_FLAG_BGR;
      }
 #  endif

 #  ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
-      if (format & PNG_FORMAT_FLAG_AFIRST)
+      if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
      {
-         if (!colormap && (format & PNG_FORMAT_FLAG_ALPHA) != 0)
+         if (colormap == 0 && (format & PNG_FORMAT_FLAG_ALPHA) != 0)
            png_set_swap_alpha(png_ptr);
         format &= ~PNG_FORMAT_FLAG_AFIRST;
      }
@@ -2237,7 +2256,7 @@ 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 && image->colormap_entries <= 16)
+   if (colormap != 0 && image->colormap_entries <= 16)
      png_set_packing(png_ptr);

   /* That should have handled all (both) the transforms. */
@@ -2275,7 +2294,8 @@ png_image_write_main(png_voidp argument)
    * before it is written.  This only applies when the input is 16-bit and
    * either there is an alpha channel or it is converted to 8-bit.
    */
-   if ((linear && alpha) || (!colormap && display->convert_to_8bit))
+   if ((linear != 0 && alpha != 0 ) ||
+       (colormap == 0 && display->convert_to_8bit != 0))
   {
      png_bytep row = png_voidcast(png_bytep, png_malloc(png_ptr,
         png_get_rowbytes(png_ptr, info_ptr)));
@@ -2324,7 +2344,7 @@ png_image_write_to_stdio(png_imagep image, FILE *file, int convert_to_8bit,
   {
      if (file != NULL)
      {
-         if (png_image_write_init(image))
+         if (png_image_write_init(image) != 0)
         {
            png_image_write_control display;
            int result;
@@ -2379,7 +2399,7 @@ 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))
+               row_stride, colormap) != 0)
            {
               int error; /* from fflush/fclose */

@@ -2430,6 +2450,6 @@ png_image_write_to_file(png_imagep image, const char *file_name,
   else
      return 0;
 }
-#endif /* PNG_STDIO_SUPPORTED */
+#endif /* STDIO */
 #endif /* SIMPLIFIED_WRITE */
-#endif /* PNG_WRITE_SUPPORTED */
+#endif /* WRITE */
--- 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 1.6.9 [February 6, 2014]
+ * Last changed in libpng 1.6.15 [November 20, 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)
+      if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
      {
         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)
+      if ((row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0)
      {
         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 /* PNG_WRITE_16BIT_SUPPORTED */
+#endif /* WRITE_16BIT */
      }

      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 /* PNG_WRITE_16BIT_SUPPORTED */
+#endif /* WRITE_16BIT */
      }
   }
 }
@@ -449,7 +449,7 @@ png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
               *(dp++) = (png_byte)(255 - *(sp++));
            }
         }
-#endif /* PNG_WRITE_16BIT_SUPPORTED */
+#endif /* WRITE_16BIT */
      }

      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 /* PNG_WRITE_16BIT_SUPPORTED */
+#endif /* WRITE_16BIT */
      }
   }
 }
@@ -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)
+   if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
      if (png_ptr->write_user_transform_fn != NULL)
         (*(png_ptr->write_user_transform_fn)) /* User write transform
                                                 function */
@@ -521,52 +521,54 @@ 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)
+   if ((png_ptr->transformations & PNG_FILLER) != 0)
      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)
+   if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
      png_do_packswap(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_WRITE_PACK_SUPPORTED
-   if (png_ptr->transformations & PNG_PACK)
+   if ((png_ptr->transformations & PNG_PACK) != 0)
      png_do_pack(row_info, png_ptr->row_buf + 1,
          (png_uint_32)png_ptr->bit_depth);
 #endif

 #ifdef PNG_WRITE_SWAP_SUPPORTED
-   if (png_ptr->transformations & PNG_SWAP_BYTES)
+#  ifdef PNG_16BIT_SUPPORTED
+   if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
      png_do_swap(row_info, png_ptr->row_buf + 1);
+#  endif
 #endif

 #ifdef PNG_WRITE_SHIFT_SUPPORTED
-   if (png_ptr->transformations & PNG_SHIFT)
+   if ((png_ptr->transformations & PNG_SHIFT) != 0)
      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)
+   if ((png_ptr->transformations & PNG_SWAP_ALPHA) != 0)
      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)
+   if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0)
      png_do_write_invert_alpha(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_WRITE_BGR_SUPPORTED
-   if (png_ptr->transformations & PNG_BGR)
+   if ((png_ptr->transformations & PNG_BGR) != 0)
      png_do_bgr(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_WRITE_INVERT_SUPPORTED
-   if (png_ptr->transformations & PNG_INVERT_MONO)
+   if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
      png_do_invert(row_info, png_ptr->row_buf + 1);
 #endif
 }
-#endif /* PNG_WRITE_TRANSFORMS_SUPPORTED */
-#endif /* PNG_WRITE_SUPPORTED */
+#endif /* WRITE_TRANSFORMS */
+#endif /* WRITE */
--- a/pngwutil.c
+++ b/pngwutil.c
@@ -1,7 +1,7 @@

 /* pngwutil.c - utilities to write a PNG file
 *
- * Last changed in libpng 1.6.14 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.15 [November 20, 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.)
@@ -211,7 +211,7 @@ png_image_size(png_structrp png_ptr)

   if (png_ptr->rowbytes < 32768 && h < 32768)
   {
-      if (png_ptr->interlaced)
+      if (png_ptr->interlaced != 0)
      {
         /* Interlacing makes the image larger because of the replication of
          * both the filter byte and the padding to a byte boundary.
@@ -286,9 +286,7 @@ optimize_cmf(png_bytep data, png_alloc_size_t data_size)
      }
   }
 }
-#else
-#  define optimize_cmf(dp,dl) ((void)0)
-#endif /* PNG_WRITE_OPTIMIZE_CMF_SUPPORTED */
+#endif /* WRITE_OPTIMIZE_CMF */

 /* Initialize the compressor for the appropriate type of compression. */
 static int
@@ -297,7 +295,7 @@ png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,
 {
   if (png_ptr->zowner != 0)
   {
-#     if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_ERROR_TEXT_SUPPORTED)
+#if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_ERROR_TEXT_SUPPORTED)
      char msg[64];

      PNG_STRING_FROM_CHUNK(msg, owner);
@@ -309,8 +307,8 @@ png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,
       * are minimal.
       */
      (void)png_safecat(msg, (sizeof msg), 10, " using zstream");
-#     endif
-#     if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
+#endif
+#if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
         png_warning(png_ptr, msg);

         /* Attempt sane error recovery */
@@ -321,9 +319,9 @@ png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,
         }

         png_ptr->zowner = 0;
-#     else
+#else
         png_error(png_ptr, msg);
-#     endif
+#endif
   }

   {
@@ -336,7 +334,7 @@ png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,

      if (owner == png_IDAT)
      {
-         if (png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY)
+         if ((png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY) != 0)
            strategy = png_ptr->zlib_strategy;

         else if (png_ptr->do_filter != PNG_FILTER_NONE)
@@ -348,20 +346,20 @@ png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,

      else
      {
-#        ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
            level = png_ptr->zlib_text_level;
            method = png_ptr->zlib_text_method;
            windowBits = png_ptr->zlib_text_window_bits;
            memLevel = png_ptr->zlib_text_mem_level;
            strategy = png_ptr->zlib_text_strategy;
-#        else
+#else
            /* If customization is not supported the values all come from the
             * IDAT values except for the strategy, which is fixed to the
             * default.  (This is the pre-1.6.0 behavior too, although it was
             * implemented in a very different way.)
             */
            strategy = Z_DEFAULT_STRATEGY;
-#        endif
+#endif
      }

      /* Adjust 'windowBits' down if larger than 'data_size'; to stop this
@@ -388,7 +386,7 @@ png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,
      }

      /* Check against the previous initialized values, if any. */
-      if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) &&
+      if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0 &&
         (png_ptr->zlib_set_level != level ||
         png_ptr->zlib_set_method != method ||
         png_ptr->zlib_set_window_bits != windowBits ||
@@ -412,7 +410,7 @@ png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,
      /* Now initialize if required, setting the new parameters, otherwise just
       * to a simple reset to the previous parameters.
       */
-      if (png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED)
+      if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
         ret = deflateReset(&png_ptr->zstream);

      else
@@ -619,9 +617,10 @@ png_text_compress(png_structrp png_ptr, png_uint_32 chunk_name,
       */
      if (ret == Z_STREAM_END && input_len == 0)
      {
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
         /* Fix up the deflate header, if required */
         optimize_cmf(comp->output, comp->input_len);
-
+#endif
         /* But Z_OK is returned, not Z_STREAM_END; this allows the claim
          * function above to return Z_STREAM_END on an error (though it never
          * does in the current versions of zlib.)
@@ -664,7 +663,7 @@ png_write_compressed_data_out(png_structrp png_ptr, compression_state *comp)
   if (output_len > 0)
      png_error(png_ptr, "error writing ancillary chunked compressed data");
 }
-#endif /* PNG_WRITE_COMPRESSED_TEXT_SUPPORTED */
+#endif /* WRITE_COMPRESSED_TEXT */

 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \
    defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
@@ -717,7 +716,7 @@ png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key)
         bad_character = ch; /* just skip it, record the first error */
   }

-   if (key_len > 0 && space) /* trailing space */
+   if (key_len > 0 && space != 0) /* trailing space */
   {
      --key_len, --new_key;
      if (bad_character == 0)
@@ -732,7 +731,7 @@ png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key)

 #ifdef PNG_WARNINGS_SUPPORTED
   /* Try to only output one warning per keyword: */
-   if (*key) /* keyword too long */
+   if (*key != 0) /* keyword too long */
      png_warning(png_ptr, "keyword truncated");

   else if (bad_character != 0)
@@ -744,11 +743,11 @@ png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key)

      png_formatted_warning(png_ptr, p, "keyword \"@1\": bad character '0x@2'");
   }
-#endif /* PNG_WARNINGS_SUPPORTED */
+#endif /* WARNINGS */

   return key_len;
 }
-#endif
+#endif /* WRITE_TEXT || WRITE_pCAL || WRITE_iCCP || WRITE_sPLT */

 /* Write the IHDR chunk, and update the png_struct with the necessary
 * information.  Note that the rest of this code depends upon this
@@ -849,8 +848,8 @@ png_write_IHDR(png_structrp png_ptr, png_uint_32 width, png_uint_32 height,
    */
   if (
 #ifdef PNG_MNG_FEATURES_SUPPORTED
-       !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
-       ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) == 0) &&
+       !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
+       ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) == 0) &&
       (color_type == PNG_COLOR_TYPE_RGB ||
        color_type == PNG_COLOR_TYPE_RGB_ALPHA) &&
       (filter_type == PNG_INTRAPIXEL_DIFFERENCING)) &&
@@ -931,7 +930,7 @@ png_write_PLTE(png_structrp png_ptr, png_const_colorp palette,

   if ((
 #ifdef PNG_MNG_FEATURES_SUPPORTED
-       !(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) &&
+       (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0 &&
 #endif
       num_pal == 0) || num_pal > 256)
   {
@@ -947,7 +946,7 @@ png_write_PLTE(png_structrp png_ptr, png_const_colorp palette,
      }
   }

-   if (!(png_ptr->color_type&PNG_COLOR_MASK_COLOR))
+   if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
   {
      png_warning(png_ptr,
          "Ignoring request to write a PLTE chunk in grayscale PNG");
@@ -1074,11 +1073,11 @@ png_compress_IDAT(png_structrp png_ptr, png_const_bytep input,
         /* Write an IDAT containing the data then reset the buffer.  The
          * first IDAT may need deflate header optimization.
          */
-#        ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
-            if (!(png_ptr->mode & PNG_HAVE_IDAT) &&
-               png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
+            if ((png_ptr->mode & PNG_HAVE_IDAT) == 0 &&
+                png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
               optimize_cmf(data, png_image_size(png_ptr));
-#        endif
+#endif

         png_write_complete_chunk(png_ptr, png_IDAT, data, size);
         png_ptr->mode |= PNG_HAVE_IDAT;
@@ -1120,11 +1119,11 @@ png_compress_IDAT(png_structrp png_ptr, png_const_bytep input,
         png_bytep data = png_ptr->zbuffer_list->output;
         uInt size = png_ptr->zbuffer_size - png_ptr->zstream.avail_out;

-#        ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
-            if (!(png_ptr->mode & PNG_HAVE_IDAT) &&
-               png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
-               optimize_cmf(data, png_image_size(png_ptr));
-#        endif
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
+         if ((png_ptr->mode & PNG_HAVE_IDAT) == 0 &&
+             png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
+            optimize_cmf(data, png_image_size(png_ptr));
+#endif

         png_write_complete_chunk(png_ptr, png_IDAT, data, size);
         png_ptr->zstream.avail_out = 0;
@@ -1345,7 +1344,7 @@ png_write_sBIT(png_structrp png_ptr, png_const_color_8p sbit, int color_type)
   png_debug(1, "in png_write_sBIT");

   /* Make sure we don't depend upon the order of PNG_COLOR_8 */
-   if (color_type & PNG_COLOR_MASK_COLOR)
+   if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
   {
      png_byte maxbits;

@@ -1378,7 +1377,7 @@ png_write_sBIT(png_structrp png_ptr, png_const_color_8p sbit, int color_type)
      size = 1;
   }

-   if (color_type & PNG_COLOR_MASK_ALPHA)
+   if ((color_type & PNG_COLOR_MASK_ALPHA) != 0)
   {
      if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth)
      {
@@ -1465,9 +1464,9 @@ png_write_tRNS(png_structrp png_ptr, png_const_bytep trans_alpha,
      png_save_uint_16(buf + 2, tran->green);
      png_save_uint_16(buf + 4, tran->blue);
 #ifdef PNG_WRITE_16BIT_SUPPORTED
-      if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))
+      if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]) != 0)
 #else
-      if (buf[0] | buf[2] | buf[4])
+      if ((buf[0] | buf[2] | buf[4]) != 0)
 #endif
      {
         png_app_warning(png_ptr,
@@ -1498,8 +1497,8 @@ png_write_bKGD(png_structrp png_ptr, png_const_color_16p back, int color_type)
   {
      if (
 #ifdef PNG_MNG_FEATURES_SUPPORTED
-          (png_ptr->num_palette ||
-          (!(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE))) &&
+          (png_ptr->num_palette != 0 ||
+          (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0) &&
 #endif
         back->index >= png_ptr->num_palette)
      {
@@ -1511,15 +1510,15 @@ png_write_bKGD(png_structrp png_ptr, png_const_color_16p back, int color_type)
      png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)1);
   }

-   else if (color_type & PNG_COLOR_MASK_COLOR)
+   else if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
   {
      png_save_uint_16(buf, back->red);
      png_save_uint_16(buf + 2, back->green);
      png_save_uint_16(buf + 4, back->blue);
 #ifdef PNG_WRITE_16BIT_SUPPORTED
-      if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))
+      if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]) != 0)
 #else
-      if (buf[0] | buf[2] | buf[4])
+      if ((buf[0] | buf[2] | buf[4]) != 0)
 #endif
      {
         png_warning(png_ptr,
@@ -1986,12 +1985,13 @@ png_write_start_row(png_structrp png_ptr)
   }

   /* We only need to keep the previous row if we are using one of these. */
-   if (png_ptr->do_filter & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH))
+   if ((png_ptr->do_filter &
+      (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH)) != 0)
   {
      /* Set up previous row buffer */
      png_ptr->prev_row = (png_bytep)png_calloc(png_ptr, buf_size);

-      if (png_ptr->do_filter & PNG_FILTER_UP)
+      if ((png_ptr->do_filter & PNG_FILTER_UP) != 0)
      {
         png_ptr->up_row = (png_bytep)png_malloc(png_ptr,
            png_ptr->rowbytes + 1);
@@ -1999,7 +1999,7 @@ png_write_start_row(png_structrp png_ptr)
         png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;
      }

-      if (png_ptr->do_filter & PNG_FILTER_AVG)
+      if ((png_ptr->do_filter & PNG_FILTER_AVG) != 0)
      {
         png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,
             png_ptr->rowbytes + 1);
@@ -2007,7 +2007,7 @@ png_write_start_row(png_structrp png_ptr)
         png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;
      }

-      if (png_ptr->do_filter & PNG_FILTER_PAETH)
+      if ((png_ptr->do_filter & PNG_FILTER_PAETH) != 0)
      {
         png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,
             png_ptr->rowbytes + 1);
@@ -2015,13 +2015,13 @@ png_write_start_row(png_structrp png_ptr)
         png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
      }
   }
-#endif /* PNG_WRITE_FILTER_SUPPORTED */
+#endif /* WRITE_FILTER */

 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
   /* If interlaced, we need to set up width and height of pass */
-   if (png_ptr->interlaced)
+   if (png_ptr->interlaced != 0)
   {
-      if (!(png_ptr->transformations & PNG_INTERLACE))
+      if ((png_ptr->transformations & PNG_INTERLACE) == 0)
      {
         png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
             png_pass_ystart[0]) / png_pass_yinc[0];
@@ -2076,10 +2076,10 @@ png_write_finish_row(png_structrp png_ptr)

 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
   /* If interlaced, go to next pass */
-   if (png_ptr->interlaced)
+   if (png_ptr->interlaced != 0)
   {
      png_ptr->row_number = 0;
-      if (png_ptr->transformations & PNG_INTERLACE)
+      if ((png_ptr->transformations & PNG_INTERLACE) != 0)
      {
         png_ptr->pass++;
      }
@@ -2104,7 +2104,7 @@ png_write_finish_row(png_structrp png_ptr)
                png_pass_ystart[png_ptr->pass]) /
                png_pass_yinc[png_ptr->pass];

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

         } while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0);
@@ -2383,7 +2383,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
   /* We don't need to test the 'no filter' case if this is the only filter
    * that has been chosen, as it doesn't actually do anything to the data.
    */
-   if ((filter_to_do & PNG_FILTER_NONE) && filter_to_do != PNG_FILTER_NONE)
+   if ((filter_to_do & PNG_FILTER_NONE) != 0 && filter_to_do != PNG_FILTER_NONE)
   {
      png_bytep rp;
      png_uint_32 sum = 0;
@@ -2459,7 +2459,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
      best_row = png_ptr->sub_row;
   }

-   else if (filter_to_do & PNG_FILTER_SUB)
+   else if ((filter_to_do & PNG_FILTER_SUB) != 0)
   {
      png_bytep rp, dp, lp;
      png_uint_32 sum = 0, lmins = mins;
@@ -2580,7 +2580,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
      best_row = png_ptr->up_row;
   }

-   else if (filter_to_do & PNG_FILTER_UP)
+   else if ((filter_to_do & PNG_FILTER_UP) != 0)
   {
      png_bytep rp, dp, pp;
      png_uint_32 sum = 0, lmins = mins;
@@ -2694,7 +2694,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
      best_row = png_ptr->avg_row;
   }

-   else if (filter_to_do & PNG_FILTER_AVG)
+   else if ((filter_to_do & PNG_FILTER_AVG) != 0)
   {
      png_bytep rp, dp, pp, lp;
      png_uint_32 sum = 0, lmins = mins;
@@ -2796,7 +2796,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
   }

   /* Paeth filter */
-   if (filter_to_do == PNG_FILTER_PAETH)
+   if ((filter_to_do == PNG_FILTER_PAETH) != 0)
   {
      png_bytep rp, dp, pp, cp, lp;
      png_size_t i;
@@ -2835,7 +2835,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
      best_row = png_ptr->paeth_row;
   }

-   else if (filter_to_do & PNG_FILTER_PAETH)
+   else if ((filter_to_do & PNG_FILTER_PAETH) != 0)
   {
      png_bytep rp, dp, pp, cp, lp;
      png_uint_32 sum = 0, lmins = mins;
@@ -2905,7 +2905,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
         pc = (p + pc) < 0 ? -(p + pc) : p + pc;
 #endif
         p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
-#else /* PNG_SLOW_PAETH */
+#else /* SLOW_PAETH */
         p = a + b - c;
         pa = abs(p - a);
         pb = abs(p - b);
@@ -2919,7 +2919,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)

         else
            p = c;
-#endif /* PNG_SLOW_PAETH */
+#endif /* SLOW_PAETH */

         v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);

@@ -2968,7 +2968,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
         best_row = png_ptr->paeth_row;
      }
   }
-#endif /* PNG_WRITE_FILTER_SUPPORTED */
+#endif /* WRITE_FILTER */

   /* Do the actual writing of the filtered row data from the chosen filter. */
   png_write_filtered_row(png_ptr, best_row, row_info->rowbytes+1);
@@ -2988,7 +2988,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
      png_ptr->prev_filters[j] = best_row[0];
   }
 #endif
-#endif /* PNG_WRITE_FILTER_SUPPORTED */
+#endif /* WRITE_FILTER */
 }


@@ -3024,6 +3024,6 @@ png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row,
   {
      png_write_flush(png_ptr);
   }
-#endif
+#endif /* WRITE_FLUSH */
 }
-#endif /* PNG_WRITE_SUPPORTED */
+#endif /* WRITE */
--- a/projects/vstudio/readme.txt
+++ b/projects/vstudio/readme.txt
@@ -1,7 +1,7 @@

 VisualStudio instructions

-libpng version 1.6.14beta06 - October 5, 2014
+libpng version 1.6.16 - December 22, 2014

 Copyright (c) 1998-2010 Glenn Randers-Pehrson

--- a/projects/vstudio/zlib.props
+++ b/projects/vstudio/zlib.props
@@ -2,7 +2,7 @@
 <!--
 * zlib.props - location of zlib source
 *
- * libpng version 1.6.14beta06 - October 5, 2014
+ * libpng version 1.6.16 - December 22, 2014
 *
 * Copyright (c) 1998-2011 Glenn Randers-Pehrson
 *
--- a/scripts/README.txt
+++ b/scripts/README.txt
@@ -1,9 +1,9 @@

-Makefiles for  libpng version 1.6.14beta06 - October 5, 2014
+Makefiles for  libpng version 1.6.16 - December 22, 2014

 pnglibconf.h.prebuilt       =>  Stores configuration settings
 makefile.linux    =>  Linux/ELF makefile
-                       (gcc, creates libpng16.so.16.1.6.14beta06)
+                       (gcc, creates libpng16.so.16.1.6.16)
 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 libpng16.so.16.1.6.14beta06)
+                       creates libpng16.so.16.1.6.16)
 makefile.sgi      =>  Silicon Graphics IRIX makefile (cc, creates static lib)
 makefile.solaris  =>  Solaris 2.X makefile (gcc,
-                       creates libpng16.so.16.1.6.14beta06)
+                       creates libpng16.so.16.1.6.16)
 makefile.so9      =>  Solaris 9 makefile (gcc,
-                       creates libpng16.so.16.1.6.14beta06)
+                       creates libpng16.so.16.1.6.16)
 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.dfn - define format of libpng.def
+/* def.c - define format of libpng.def
 *
- * Last changed in libpng version 1.5.7 [December 15, 2011]
- * Copyright (c) 2010-2011 Glenn Randers-Pehrson
+ * Last changed in libpng version 1.6.16 [December 22, 2014]
+ * Copyright (c) 2011-2014 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 1.6.14beta06"
+PNG_DFN ";Version 1.6.16"

 #define PNG_EXPORTA(ordinal, type, name, args, attributes)\
        PNG_DFN "@" SYMBOL_PREFIX "@@" name "@"
--- a/scripts/intprefix.dfn
+++ b/scripts/intprefix.dfn
@@ -1,8 +1,8 @@

-/* intprefix.dfn - generate an unprefixed internal symbol list
+/* intprefix.c - generate an unprefixed internal symbol list
 *
- * Last changed in libpng version 1.6.0 [January 30, 2012]
- * Copyright (c) 2012 Glenn Randers-Pehrson
+ * Last changed in libpng version 1.6.16 [December 22, 2014]
+ * Copyright (c) 2013-2014 Glenn Randers-Pehrson
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
--- a/scripts/libpng-config-head.in
+++ b/scripts/libpng-config-head.in
@@ -11,7 +11,7 @@

 # Modeled after libxml-config.

-version=1.6.14beta06
+version=1.6.16
 prefix=""
 libdir=""
 libs=""
--- a/scripts/libpng.pc.in
+++ b/scripts/libpng.pc.in
@@ -5,6 +5,6 @@ includedir=@includedir@/libpng16

 Name: libpng
 Description: Loads and saves PNG files
-Version: 1.6.14beta06
+Version: 1.6.16
 Libs: -L${libdir} -lpng16
 Cflags: -I${includedir}
--- a/scripts/makefile.bc32
+++ b/scripts/makefile.bc32
@@ -52,7 +52,9 @@ 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.bor
+++ b/scripts/makefile.bor
@@ -60,7 +60,9 @@ 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
@@ -23,7 +23,7 @@

 VERMAJ = 1
 VERMIN = 6
-VERMIC = 14
+VERMIC = 16
 VER = $(VERMAJ).$(VERMIN).$(VERMIC)
 NAME = libpng
 PACKAGE = $(NAME)-$(VER)
--- a/scripts/makefile.darwin
+++ b/scripts/makefile.darwin
@@ -36,12 +36,11 @@ 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 $(ARCH)
-LDFLAGS=-L. -L$(ZLIBLIB) -lpng16 -lz $(ARCH)
+CFLAGS=-W -Wall -O -funroll-loops
+LDFLAGS=-L. -L$(ZLIBLIB) -lpng16 -lz

 INCPATH=$(prefix)/include
 LIBPATH=$(exec_prefix)/lib
@@ -113,7 +112,7 @@ $(LIBSOMAJ): $(OBJSDLL)
 	$(CC) -dynamiclib \
 	 -install_name $(LIBPATH)/$(LIBSOMAJ) \
 	 -current_version 16 -compatibility_version 16 \
-	 $(ARCH) -o $(LIBSOMAJ) \
+	 -o $(LIBSOMAJ) \
 	 $(OBJSDLL) -L$(ZLIBLIB) -lz

 pngtest: pngtest.o $(LIBSO)
--- a/scripts/makefile.linux
+++ b/scripts/makefile.linux
@@ -10,7 +10,7 @@
 # Library name:
 LIBNAME = libpng16
 PNGMAJ = 16
-RELEASE = 14
+RELEASE = 16

 # Shared library names:
 LIBSO=$(LIBNAME).so
--- a/scripts/makefile.msys
+++ b/scripts/makefile.msys
@@ -18,7 +18,7 @@ exec_prefix=$(prefix)
 # Library name:
 LIBNAME = libpng16
 PNGMAJ = 16
-RELEASE = 14
+RELEASE = 16

 # Shared library names:
 LIBSO=$(LIBNAME).dll
--- a/scripts/makefile.ne12bsd
+++ b/scripts/makefile.ne12bsd
@@ -17,7 +17,7 @@ INCSDIR=${LOCALBASE}/include/libpng16

 LIB=	png16
 SHLIB_MAJOR=	0
-SHLIB_MINOR=	1.6.14beta06
+SHLIB_MINOR=	1.6.16
 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
@@ -17,7 +17,7 @@ INCSDIR=${LOCALBASE}/include

 LIB=	png
 SHLIB_MAJOR=	16
-SHLIB_MINOR=	1.6.14beta06
+SHLIB_MINOR=	1.6.16
 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
@@ -11,7 +11,7 @@ LIBDIR=	${PREFIX}/lib
 MANDIR= ${PREFIX}/man/cat

 SHLIB_MAJOR=	16
-SHLIB_MINOR=	1.6.14beta06
+SHLIB_MINOR=	1.6.16

 LIB=	png
 SRCS=	png.c pngerror.c pngget.c pngmem.c pngpread.c \
--- a/scripts/makefile.tc3
+++ b/scripts/makefile.tc3
@@ -16,7 +16,9 @@ CP=copy

 # Pre-built configuration
 # See scripts\pnglibconf.mak for more options
+!ifndef PNGLIBCONF_H_PREBUILT
 PNGLIBCONF_H_PREBUILT = scripts\pnglibconf.h.prebuilt
+!endif

 O=.obj
 E=.exe
--- a/scripts/makefile.vcwin32
+++ b/scripts/makefile.vcwin32
@@ -16,7 +16,7 @@ CC = cl
 LD = link
 AR = lib
 CPPFLAGS = -I..\zlib
-CFLAGS  = -nologo -D_CRT_SECURE_NO_DEPRECATE -MD -O2 -W3
+CFLAGS  = -nologo -D_CRT_SECURE_NO_DEPRECATE -D_CRT_SECURE_NO_WARNINGS -MD -O2 -W3
 LDFLAGS = -nologo
 ARFLAGS = -nologo
 CP = copy
--- a/scripts/pnglibconf.dfa
+++ b/scripts/pnglibconf.dfa
@@ -221,7 +221,7 @@ option SET_OPTION disabled
 # ARM_NEON_API:   (PNG_ARM_NEON == 1) allow the optimization to be switched on
 #                 with png_set_option
 # ARM_NEON_CHECK: (PNG_ARM_NEON == 1) compile a run-time check to see if Neon
-#                 extensions are supported, this is poorly supported and
+#                 extensions are supported. This is poorly supported and
 #                 deprectated - use the png_set_option API.
 setting ARM_NEON_OPT
 option ARM_NEON_API disabled requires ALIGNED_MEMORY enables SET_OPTION,
@@ -303,7 +303,7 @@ option BENIGN_READ_ERRORS requires BENIGN_ERRORS
 option MNG_FEATURES

 # Arithmetic options, the first is the big switch that chooses between internal
-# floating and fixed point arithmetic implementations - it does not affect an
+# floating and fixed point arithmetic implementations - it does not affect any
 # APIs.  The second two (the _POINT settings) switch off individual APIs.
 #
 # Prior to libpng 1.6.8 one of the API (_POINT) variants had to be selected.  At
@@ -839,7 +839,6 @@ option WRITE_COMPRESSED_TEXT disabled
 option WRITE_iCCP enables WRITE_COMPRESSED_TEXT
 option WRITE_iTXt enables WRITE_COMPRESSED_TEXT
 option WRITE_zTXt enables WRITE_COMPRESSED_TEXT
-option WRITE_COMPRESSED_TEXT enables WRITE_TEXT

 # Turn this off to disable png_read_png() and png_write_png() and
 # leave the row_pointers member out of the info structure.
--- a/scripts/pnglibconf.h.prebuilt
+++ b/scripts/pnglibconf.h.prebuilt
@@ -1,8 +1,8 @@
-/* libpng 1.6.14beta06 STANDARD API DEFINITION */
+/* libpng 1.6.16 STANDARD API DEFINITION */

 /* pnglibconf.h - library build configuration */

-/* Libpng version 1.6.14beta06 - October 5, 2014 */
+/* Libpng version 1.6.16 - December 22, 2014 */

 /* Copyright (c) 1998-2014 Glenn Randers-Pehrson */

--- a/scripts/prefix.dfn
+++ b/scripts/prefix.dfn
@@ -1,8 +1,8 @@

-/* prefix.dfn - generate an unprefixed symbol list
+/* prefix.c - generate an unprefixed symbol list
 *
- * Last changed in libpng version 1.6.0 [January 30, 2012]
- * Copyright (c) 2012 Glenn Randers-Pehrson
+ * Last changed in libpng version 1.6.16 [December 22, 2014]
+ * Copyright (c) 2013-2014 Glenn Randers-Pehrson
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
--- a/scripts/sym.dfn
+++ b/scripts/sym.dfn
@@ -1,8 +1,8 @@

-/* sym.dfn - define format of libpng.sym
+/* sym.c - define format of libpng.sym
 *
- * Last changed in libpng version 1.5.0 [January 6, 2011]
- * Copyright (c) 1998-2011 Glenn Randers-Pehrson
+ * Last changed in libpng version 1.6.16 [December 22, 2014]
+ * Copyright (c) 2011-2014 Glenn Randers-Pehrson
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
--- a/scripts/symbols.dfn
+++ b/scripts/symbols.dfn
@@ -1,8 +1,8 @@

-/* symbols.dfn - find all exported symbols
+/* symbols.c - find all exported symbols
 *
- * Last changed in libpng version 1.5.0 [January 6, 2011]
- * Copyright (c) 1998-2011 Glenn Randers-Pehrson
+ * Last changed in libpng version 1.6.16 [December 22, 2014]
+ * Copyright (c) 2011-2014 Glenn Randers-Pehrson
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
--- a/scripts/symbols.def
+++ b/scripts/symbols.def
@@ -1,4 +1,4 @@
-;Version 1.6.14beta06
+;Version 1.6.16
 ;--------------------------------------------------------------
 ; LIBPNG symbol list as a Win32 DEF file
 ; Contains all the symbols that can be exported from libpng
--- a/scripts/vers.dfn
+++ b/scripts/vers.dfn
@@ -1,8 +1,8 @@

-/* vers.dfn - define format of libpng.vers
+/* vers.c - define format of libpng.vers
 *
- * Last changed in libpng version 1.5.0 [January 6, 2011]
- * Copyright (c) 1998-2011 Glenn Randers-Pehrson
+ * Last changed in libpng version 1.6.16 [December 22, 2014]
+ * Copyright (c) 2011-2014 Glenn Randers-Pehrson
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer