[master] Imported from libpng-1.6.29.tar

[master] Imported from libpng-1.6.28.tar
[master] Imported from libpng-1.6.27.tar
2025-07-10 18:04:09 +02:00 · 2017-03-16 07:27:43 -05:00 · 2017-01-05 11:50:11 -05:00 · 2016-12-29 08:10:06 -06:00 · 2016-10-19 19:11:48 -05:00 · 2016-08-31 22:30:55 -05:00
140 changed files with 540 additions and 2521 deletions
--- a/64
+++ b/64
@@ -1,4 +1,4 @@
-Libpng 1.6.33 - September 28, 2017
+Libpng 1.6.29 - March 16, 2017

 This is a public release of libpng, intended for use in production codes.

@@ -7,53 +7,37 @@ Files available for download:
 Source files with LF line endings (for Unix/Linux) and with a
 "configure" script

-   libpng-1.6.33.tar.xz (LZMA-compressed, recommended)
-   libpng-1.6.33.tar.gz
+   libpng-1.6.29.tar.xz (LZMA-compressed, recommended)
+   libpng-1.6.29.tar.gz

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

-   lpng1633.7z  (LZMA-compressed, recommended)
-   lpng1633.zip
+   lpng1629.7z  (LZMA-compressed, recommended)
+   lpng1629.zip

 Other information:

-   libpng-1.6.33-README.txt
-   libpng-1.6.33-LICENSE.txt
-   libpng-1.6.33-*.asc (armored detached GPG signatures)
+   libpng-1.6.29-README.txt
+   libpng-1.6.29-LICENSE.txt
+   libpng-1.6.29-*.asc (armored detached GPG signatures)

-Changes since the last public release (1.6.32):
-  Added PNGMINUS_UNUSED macro to contrib/pngminus/p*.c and added missing
-    parenthesis in contrib/pngminus/pnm2png.c (bug report by Christian Hesse).
-  Fixed off-by-one error in png_do_check_palette_indexes() (Bug report
-    by Mick P., Source Forge Issue #269).
-  Initialize png_handler.row_ptr in contrib/oss-fuzz/libpng_read_fuzzer.cc
-    to fix shortlived oss-fuzz issue 3234.
-  Compute a larger limit on IDAT because some applications write a deflate
-    buffer for each row (Bug report by Andrew Church).
-  Use current date (DATE) instead of release-date (RDATE) in last
-    changed date of contrib/oss-fuzz files.
-  Enabled ARM support in CMakeLists.txt (Bernd Kuhls).
-  Fixed incorrect typecast of some arguments to png_malloc() and
-    png_calloc() that were png_uint_32 instead of png_alloc_size_t
-    (Bug report by "irwir" in Github libpng issue #175).
-  Use pnglibconf.h.prebuilt when building for ANDROID with cmake (Github
-    issue 162, by rcdailey).
-  Initialize memory allocated by png_inflate to zero, using memset, to
-    stop an oss-fuzz "use of uninitialized value" detection in png_set_text_2()
-    due to truncated iTXt or zTXt chunk.
-  Initialize memory allocated by png_read_buffer to zero, using memset, to
-    stop an oss-fuzz "use of uninitialized value" detection in
-    png_icc_check_tag_table() due to truncated iCCP chunk.
-  Removed a redundant test (suggested by "irwir" in Github issue #180).
-  Added an interlaced version of each file in contrib/pngsuite.
-  Relocate new memset() call in pngrutil.c.
-  Removed more redundant tests (suggested by "irwir" in Github issue #180).
-  Add support for loading images with associated alpha in the Simplified
-    API (Samuel Williams).
-  Revert contrib/oss-fuzz/libpng_read_fuzzer.cc to libpng-1.6.32 state.
-  Initialize png_handler.row_ptr in contrib/oss-fuzz/libpng_read_fuzzer.cc
-  Add end_info structure and png_read_end() to the libpng fuzzer.
+Changes since the last public release (1.6.28):
+
+  Readded "include(GNUInstallDirs)" to CMakeLists.txt (Gianfranco Costamagna).
+  Moved SSE2 optimization code into the main libpng source directory.
+    Configure libpng with "configure --enable-intel-sse" or compile
+    libpng with "-DPNG_INTEL_SSE" in CPPFLAGS to enable it.
+  Simplified conditional compilation in pngvalid.c, for AIX (Michael Felt).
+  Avoid conditional directives that break statements in pngrutil.c (Romero
+    Malaquias)
+  The contrib/examples/pngtopng.c recovery code was in the wrong "if"
+    branches; the comments were correct.
+  Added code for PowerPC VSX optimisation (Vadim Barkov).
+  Avoid potential overflow of shift operations in png_do_expand() (Aaron Boxer).
+  Change test ZLIB_VERNUM >= 0x1281 to ZLIB_VERNUM >= 0x1290 in pngrutil.c
+    because Solaris 11 distributes zlib-1.2.8.f that is older than 1.2.8.1.
+  Suppress clang warnings about implicit sign changes in png.c

 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
--- a/226
+++ b/226
@@ -833,7 +833,7 @@ Version 1.0.7beta11 [May 7, 2000]
  Removed the new PNG_CREATED_READ_STRUCT and PNG_CREATED_WRITE_STRUCT modes
    which are no longer used.
  Eliminated the three new members of png_text when PNG_LEGACY_SUPPORTED is
-    defined or when neither PNG_READ_iTXt_SUPPORTED nor PNG_WRITE_iTXt_SUPPORTED
+    defined or when neither PNG_READ_iTXt_SUPPORTED nor PNG_WRITE_iTXT_SUPPORTED
    is defined.
  Made PNG_NO_READ|WRITE_iTXt the default setting, to avoid memory
    overrun when old applications fill the info_ptr->text structure directly.
@@ -5761,9 +5761,7 @@ Version 1.6.27beta01 [November 2, 2016]
    if built with zlib-1.2.8.1.

 Version 1.6.27rc01 [December 27, 2016]
-  Control ADLER32 checking with new PNG_IGNORE_ADLER32 option. Fixes
-    an endless loop when handling erroneous ADLER32 checksums; bug
-    introduced in libpng-1.6.26.
+  Control ADLER32 checking with new PNG_IGNORE_ADLER32 option.
  Removed the use of a macro containing the pre-processor 'defined'
    operator.  It is unclear whether this is valid; a macro that
    "generates" 'defined' is not permitted, but the use of the word
@@ -5813,230 +5811,12 @@ Version 1.6.29beta02 [February 22, 2017]
 Version 1.6.29beta03 [March 1, 2017]
  Avoid potential overflow of shift operations in png_do_expand() (Aaron Boxer).
  Change test ZLIB_VERNUM >= 0x1281 to ZLIB_VERNUM >= 0x1290 in pngrutil.c
-    because Solaris 11 distributes zlib-1.2.8.f that is older than 1.2.8.1,
-    as suggested in zlib FAQ, item 24.
+    because Solaris 11 distributes zlib-1.2.8.f that is older than 1.2.8.1.
  Suppress clang warnings about implicit sign changes in png.c

 Version 1.6.29 [March 16, 2017]
  No changes.

-Version 1.6.30beta01 [April 1, 2017]
-  Added missing "$(CPPFLAGS)" to the compile line for c.pic.o in
-    makefile.linux and makefile.solaris-x86 (Cosmin).
-  Revised documentation of png_get_error_ptr() in the libpng manual.
-  Silence clang -Wcomma and const drop warnings (Viktor Szakats).
-  Update Sourceforge URLs in documentation (https instead of http).
-
-Version 1.6.30beta02 [April 22, 2017]
-  Document need to check for integer overflow when allocating a pixel
-    buffer for multiple rows in contrib/gregbook, contrib/pngminus,
-    example.c, and in the manual (suggested by Jaeseung Choi). This
-    is similar to the bug reported against pngquant in CVE-2016-5735.
-  Removed reference to the obsolete PNG_SAFE_LIMITS macro in the documentation.
-
-Version 1.6.30beta03 [May 22, 2017]
-  Check for integer overflow in contrib/visupng and contrib/tools/genpng.
-  Do not double evaluate CMAKE_SYSTEM_PROCESSOR in CMakeLists.txt.
-  Test CMAKE_HOST_WIN32 instead of WIN32 in CMakeLists.txt.
-  Fix some URL in documentation.
-
-Version 1.6.30beta04 [June 7, 2017]
-  Avoid writing an empty IDAT when the last IDAT exactly fills the
-    compression buffer (bug report by Brian Baird). This bug was
-    introduced in libpng-1.6.0.
-
-Version 1.6.30rc01 [June 14, 2017]
-  No changes.
-
-Version 1.6.30rc02 [June 25, 2017]
-  Update copyright year in pnglibconf.h, make ltmain.sh executable.
-  Add a reference to the libpng.download site in README.
-
-Version 1.6.30 [June 28, 2017]
-  No changes.
-
-Version 1.6.31beta01 [July 5, 2017]
-  Guard the definition of _POSIX_SOURCE in pngpriv.h (AIX already defines it;
-    bug report by Michael Felt).
-  Revised pngpriv.h to work around failure to compile arm/filter_neon.S
-    ("typedef" directive is unrecognized by the assembler). The problem
-    was introduced in libpng-1.6.30beta01.
-  Added "Requires: zlib" to libpng.pc.in (Pieter Neerincx).
-  Added special case for FreeBSD in arm/filter_neon.S (Maya Rashish).
-
-Version 1.6.31beta02 [July 8, 2017]
-  Added instructions for disabling hardware optimizations in INSTALL.
-  Added "--enable-hardware-optimizations" configuration flag to enable
-    or disable all hardware optimizations with one flag.
-
-Version 1.6.31beta03 [July 9, 2017]
-  Updated CMakeLists.txt to add INTEL_SSE and MIPS_MSA platforms.
-  Changed "int" to "png_size_t" in intel/filter_sse2.c to prevent
-    possible integer overflow (Bug report by John Bowler).
-  Quieted "declaration after statement" warnings in intel/filter_sse2.c.
-  Added scripts/makefile-linux-opt, which has hardware optimizations enabled.
-
-Version 1.6.31beta04 [July 11, 2017]
-  Removed one of the GCC-7.1.0 'strict-overflow' warnings that result when
-    integers appear on both sides of a compare.  Worked around the others by
-    forcing the strict-overflow setting in the relevant functions to a level
-    where they are not reported (John Bowler).
-  Changed "FALL THROUGH" comments to "FALLTHROUGH" because GCC doesn't like
-    the space.
-  Worked around some C-style casts from (void*) because g++ 5.4.0 objects
-    to them.
-  Increased the buffer size for 'sprint' to pass the gcc 7.1.0 'sprint
-    overflow' check that is on by default with -Wall -Wextra.
-
-Version 1.6.31beta05 [July 13, 2017]
-  Added eXIf chunk support.
-
-Version 1.6.31beta06 [July 17, 2017]
-  Added a minimal eXIf chunk (with Orientation and FocalLengthIn35mmFilm
-    tags) to pngtest.png.
-
-Version 1.6.31beta07 [July 18, 2017]
-  Revised the eXIf chunk in pngtest.png to fix "Bad IFD1 Directory" warning.
-
-Version 1.6.31rc01 [July 19, 2017]
-  No changes.
-
-Version 1.6.31rc02 [July 25, 2017]
-  Fixed typo in example.c (png_free_image should be png_image_free) (Bug
-    report by John Smith)
-
-Version 1.6.31 [July 27, 2017]
-  No changes.
-
-Version 1.6.32beta01 [July 31, 2017]
-  Avoid possible NULL dereference in png_handle_eXIf when benign_errors
-    are allowed. Avoid leaking the input buffer "eXIf_buf".
-  Eliminated png_ptr->num_exif member from pngstruct.h and added num_exif
-    to arguments for png_get_eXIf() and png_set_eXIf().
-  Added calls to png_handle_eXIf(() in pngread.c and png_write_eXIf() in
-    pngwrite.c, and made various other fixes to png_write_eXIf().
-  Changed name of png_get_eXIF and png_set_eXIf() to png_get_eXIf_1() and
-    png_set_eXIf_1(), respectively, to avoid breaking API compatibility
-    with libpng-1.6.31.
-
-Version 1.6.32beta02 [August 1, 2017]
-  Updated contrib/libtests/pngunknown.c with eXIf chunk.
-
-Version 1.6.32beta03 [August 2, 2017]
-  Initialized btoa[] in pngstest.c
-  Stop memory leak when returning from png_handle_eXIf() with an error
-    (Bug report from the OSS-fuzz project).
-
-Version 1.6.32beta04 [August 2, 2017]
-  Replaced local eXIf_buf with info_ptr-eXIf_buf in png_handle_eXIf().
-  Update libpng.3 and libpng-manual.txt about eXIf functions.
-
-Version 1.6.32beta05 [August 2, 2017]
-  Restored png_get_eXIf() and png_set_eXIf() to maintain API compatability.
-
-Version 1.6.32beta06 [August 2, 2017]
-  Removed png_get_eXIf_1() and png_set_eXIf_1().
-
-Version 1.6.32beta07 [August 3, 2017]
-  Check length of all chunks except IDAT against user limit to fix an
-    OSS-fuzz issue (Fixes CVE-2017-12652).
-
-Version 1.6.32beta08 [August 3, 2017]
-  Check length of IDAT against maximum possible IDAT size, accounting
-    for height, rowbytes, interlacing and zlib/deflate overhead.
-  Restored png_get_eXIf_1() and png_set_eXIf_1(), because strlen(eXIf_buf)
-    does not work (the eXIf chunk data can contain zeroes).
-
-Version 1.6.32beta09 [August 3, 2017]
-  Require cmake-2.8.8 in CMakeLists.txt. Revised symlink creation,
-    no longer using deprecated cmake LOCATION feature (Clifford Yapp).
-  Fixed five-byte error in the calculation of IDAT maximum possible size.
-  
-Version 1.6.32beta10 [August 5, 2017]
-  Moved chunk-length check into a png_check_chunk_length() private
-    function (Suggested by Max Stepin).
-  Moved bad pngs from tests to contrib/libtests/crashers
-  Moved testing of bad pngs into a separate tests/pngtest-badpngs script
-  Added the --xfail (expected FAIL) option to pngtest.c. It writes XFAIL
-    in the output but PASS for the libpng test.
-  Require cmake-3.0.2 in CMakeLists.txt (Clifford Yapp).
-  Fix "const" declaration info_ptr argument to png_get_eXIf_1() and the
-    num_exif argument to png_get_eXIf_1() (Github Issue 171).
-
-Version 1.6.32beta11 [August 7, 2017]
-  Added "eXIf" to "chunks_to_ignore[]" in png_set_keep_unknown_chunks().
-  Added huge_IDAT.png and empty_ancillary_chunks.png to testpngs/crashers.
-  Make pngtest --strict, --relax, --xfail options imply -m (multiple).
-  Removed unused chunk_name parameter from png_check_chunk_length().
-  Relocated setting free_me for eXIf data, to stop an OSS-fuzz leak.
-  Initialize profile_header[] in png_handle_iCCP() to fix OSS-fuzz issue.
-  Initialize png_ptr->row_buf[0] to 255 in png_read_row() to fix OSS-fuzz UMR.
-  Attempt to fix a UMR in png_set_text_2() to fix OSS-fuzz issue.
-  Increase minimum zlib stream from 9 to 14 in png_handle_iCCP(), to account
-    for the minimum 'deflate' stream, and relocate the test to a point
-    after the keyword has been read.
-  Check that the eXIf chunk has at least 2 bytes and begins with "II" or "MM".
-
-Version 1.6.32rc01 [August 18, 2017]
-  Added a set of "huge_xxxx_chunk.png" files to contrib/testpngs/crashers,
-    one for each known chunk type, with length = 2GB-1.
-  Check for 0 return from png_get_rowbytes() and added some (size_t) typecasts
-    in contrib/pngminus/*.c to stop some Coverity issues (162705, 162706,
-    and 162707).
-  Renamed chunks in contrib/testpngs/crashers to avoid having files whose
-    names differ only in case; this causes problems with some platforms
-    (github issue #172).
-
-Version 1.6.32rc02 [August 22, 2017]
-  Added contrib/oss-fuzz directory which contains files used by the oss-fuzz
-    project (https://github.com/google/oss-fuzz/tree/master/projects/libpng).
-
-Version 1.6.32 [August 24, 2017]
-  No changes.
-
-Version 1.6.33beta01 [August 28, 2017]
-  Added PNGMINUS_UNUSED macro to contrib/pngminus/p*.c and added missing
-    parenthesis in contrib/pngminus/pnm2png.c (bug report by Christian Hesse).
-  Fixed off-by-one error in png_do_check_palette_indexes() (Bug report
-    by Mick P., Source Forge Issue #269).
-
-Version 1.6.33beta02 [September 3, 2017]
-  Initialize png_handler.row_ptr in contrib/oss-fuzz/libpng_read_fuzzer.cc
-    to fix shortlived oss-fuzz issue 3234.
-  Compute a larger limit on IDAT because some applications write a deflate
-    buffer for each row (Bug report by Andrew Church).
-  Use current date (DATE) instead of release-date (RDATE) in last
-    changed date of contrib/oss-fuzz files.
-  Enabled ARM support in CMakeLists.txt (Bernd Kuhls).
-
-Version 1.6.33beta03 [September 14, 2017]
-  Fixed incorrect typecast of some arguments to png_malloc() and
-    png_calloc() that were png_uint_32 instead of png_alloc_size_t
-    (Bug report by "irwir" in Github libpng issue #175).
-  Use pnglibconf.h.prebuilt when building for ANDROID with cmake (Github
-    issue 162, by rcdailey).
-
-Version 1.6.33rc01 [September 20, 2017]
-  Initialize memory allocated by png_inflate to zero, using memset, to
-    stop an oss-fuzz "use of uninitialized value" detection in png_set_text_2()
-    due to truncated iTXt or zTXt chunk.
-  Initialize memory allocated by png_read_buffer to zero, using memset, to
-    stop an oss-fuzz "use of uninitialized value" detection in
-    png_icc_check_tag_table() due to truncated iCCP chunk.
-  Removed a redundant test (suggested by "irwir" in Github issue #180).
-
-Version 1.6.33rc02 [September 23, 2017]
-  Added an interlaced version of each file in contrib/pngsuite.
-  Relocate new memset() call in pngrutil.c.
-  Removed more redundant tests (suggested by "irwir" in Github issue #180).
-  Add support for loading images with associated alpha in the Simplified
-    API (Samuel Williams).
-
-Version 1.6.33 [September 28, 2017]
-  Revert contrib/oss-fuzz/libpng_read_fuzzer.cc to libpng-1.6.32 state.
-  Initialize png_handler.row_ptr in contrib/oss-fuzz/libpng_read_fuzzer.cc
-  Add end_info structure and png_read_end() to the libpng fuzzer.
-
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
 https://lists.sourceforge.net/lists/listinfo/png-mng-implement
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,6 +1,6 @@
 # CMakeLists.txt

-# Copyright (C) 2007,2009-2017 Glenn Randers-Pehrson
+# Copyright (C) 2007,2009-2016 Glenn Randers-Pehrson
 # Written by Christian Ehrlicher, 2007
 # Revised by Roger Lowman, 2009-2010
 # Revised by Clifford Yapp, 2011-2012
@@ -11,8 +11,8 @@
 # For conditions of distribution and use, see the disclaimer
 # and license in png.h

-cmake_minimum_required(VERSION 3.0.2)
-cmake_policy(VERSION 3.0.2)
+cmake_minimum_required(VERSION 2.8.3)
+cmake_policy(VERSION 2.8.3)

 # Set MacOSX @rpath usage globally.
 if (POLICY CMP0020)
@@ -31,12 +31,12 @@ endif(POLICY CMP0054)

 set(CMAKE_CONFIGURATION_TYPES "Release;Debug;MinSizeRel;RelWithDebInfo")

-project(libpng ASM C)
+project(libpng C)
 enable_testing()

 set(PNGLIB_MAJOR 1)
 set(PNGLIB_MINOR 6)
-set(PNGLIB_RELEASE 33)
+set(PNGLIB_RELEASE 29)
 set(PNGLIB_NAME libpng${PNGLIB_MAJOR}${PNGLIB_MINOR})
 set(PNGLIB_VERSION ${PNGLIB_MAJOR}.${PNGLIB_MINOR}.${PNGLIB_RELEASE})

@@ -76,16 +76,12 @@ option(PNG_FRAMEWORK "Build OS X framework" OFF)
 option(PNG_DEBUG     "Build with debug output" OFF)
 option(PNGARG        "Disable ANSI-C prototypes" OFF)

-option(PNG_HARDWARE_OPTIMIZATIONS "Enable Hardware Optimizations" ON)
-
-
 set(PNG_PREFIX "" CACHE STRING "Prefix to add to the API function names")
 set(DFA_XTRA "" CACHE FILEPATH "File containing extra configuration settings")

-if(PNG_HARDWARE_OPTIMIZATIONS)
 # set definitions and sources for arm
-if(CMAKE_SYSTEM_PROCESSOR MATCHES "^arm" OR
-  CMAKE_SYSTEM_PROCESSOR MATCHES "^aarch64")
+if(${CMAKE_SYSTEM_PROCESSOR} MATCHES "^arm" OR
+  ${CMAKE_SYSTEM_PROCESSOR} MATCHES "^aarch64")
  set(PNG_ARM_NEON_POSSIBLE_VALUES check on off)
  set(PNG_ARM_NEON "check" CACHE STRING "Enable ARM NEON optimizations:
     check: (default) use internal checking code;
@@ -114,11 +110,13 @@ if(CMAKE_SYSTEM_PROCESSOR MATCHES "^arm" OR
 endif()

 # set definitions and sources for powerpc
-if(CMAKE_SYSTEM_PROCESSOR MATCHES "^powerpc*" OR
-	CMAKE_SYSTEM_PROCESSOR MATCHES "^ppc64*" )
-  set(PNG_POWERPC_VSX_POSSIBLE_VALUES on off)
-  set(PNG_POWERPC_VSX "on" CACHE STRING "Enable POWERPC VSX optimizations:
-     off: disable the optimizations.")
+if(${CMAKE_SYSTEM_PROCESSOR} MATCHES "^powerpc*" OR
+	${CMAKE_SYSTEM_PROCESSOR} MATCHES "^ppc64*" )
+  set(PNG_POWERPC_VSX_POSSIBLE_VALUES check on off)
+  set(PNG_POWERPC_VSX "check" CACHE STRING "Enable POWERPC VSX optimizations:
+     check: (default) use internal checking code;
+     off: disable the optimizations;
+     on: turn on unconditionally.")
  set_property(CACHE PNG_POWERPC_VSX PROPERTY STRINGS
     ${PNG_POWERPC_VSX_POSSIBLE_VALUES})
  list(FIND PNG_POWERPC_VSX_POSSIBLE_VALUES ${PNG_POWERPC_VSX} index)
@@ -129,62 +127,19 @@ if(CMAKE_SYSTEM_PROCESSOR MATCHES "^powerpc*" OR
    set(libpng_powerpc_sources
      powerpc/powerpc_init.c
      powerpc/filter_vsx_intrinsics.c)
+
    if(${PNG_POWERPC_VSX} STREQUAL "on")
      add_definitions(-DPNG_POWERPC_VSX_OPT=2)
+    elseif(${PNG_POWERPC_VSX} STREQUAL "check")
+      add_definitions(-DPNG_POWERPC_VSX_CHECK_SUPPORTED)
+      message(WARNING
+      "[PNG_POWERPC_VSX==check] Please check contrib/powerpc/README file for the list of supported OSes.")
    endif()
  else()
    add_definitions(-DPNG_POWERPC_VSX_OPT=0)
  endif()
 endif()

-# set definitions and sources for intel
-if(CMAKE_SYSTEM_PROCESSOR MATCHES "^i?86" OR
-	CMAKE_SYSTEM_PROCESSOR MATCHES "^x86_64*" )
-  set(PNG_INTEL_SSE_POSSIBLE_VALUES on off)
-  set(PNG_INTEL_SSE "on" CACHE STRING "Enable INTEL_SSE optimizations:
-     off: disable the optimizations")
-  set_property(CACHE PNG_INTEL_SSE PROPERTY STRINGS
-     ${PNG_INTEL_SSE_POSSIBLE_VALUES})
-  list(FIND PNG_INTEL_SSE_POSSIBLE_VALUES ${PNG_INTEL_SSE} index)
-  if(index EQUAL -1)
-    message(FATAL_ERROR
-      " PNG_INTEL_SSE must be one of [${PNG_INTEL_SSE_POSSIBLE_VALUES}]")
-  elseif(NOT ${PNG_INTEL_SSE} STREQUAL "no")
-    set(libpng_intel_sources
-      intel/intel_init.c
-      intel/filter_sse2_intrinsics.c)
-    if(${PNG_INTEL_SSE} STREQUAL "on")
-      add_definitions(-DPNG_INTEL_SSE_OPT=1)
-    endif()
-  else()
-    add_definitions(-DPNG_INTEL_SSE_OPT=0)
-  endif()
-endif()
-
-# set definitions and sources for MIPS
-if(CMAKE_SYSTEM_PROCESSOR MATCHES "mipsel*" OR
-	CMAKE_SYSTEM_PROCESSOR MATCHES "mips64el*" )
-  set(PNG_MIPS_MSA_POSSIBLE_VALUES on off)
-  set(PNG_MIPS_MSA "on" CACHE STRING "Enable MIPS_MSA optimizations:
-     off: disable the optimizations")
-  set_property(CACHE PNG_MIPS_MSA PROPERTY STRINGS
-     ${PNG_MIPS_MSA_POSSIBLE_VALUES})
-  list(FIND PNG_MIPS_MSA_POSSIBLE_VALUES ${PNG_MIPS_MSA} index)
-  if(index EQUAL -1)
-    message(FATAL_ERROR
-      " PNG_MIPS_MSA must be one of [${PNG_MIPS_MSA_POSSIBLE_VALUES}]")
-  elseif(NOT ${PNG_MIPS_MSA} STREQUAL "no")
-    set(libpng_mips_sources
-      mips/mips_init.c
-      mips/filter_msa_intrinsics.c)
-    if(${PNG_MIPS_MSA} STREQUAL "on")
-      add_definitions(-DPNG_MIPS_MSA_OPT=2)
-    endif()
-  else()
-    add_definitions(-DPNG_MIPS_MSA_OPT=0)
-  endif()
-endif()
-endif(PNG_HARDWARE_OPTIMIZATIONS)

 # SET LIBNAME
 set(PNG_LIB_NAME png${PNGLIB_MAJOR}${PNGLIB_MINOR})
@@ -262,7 +217,7 @@ find_program(AWK NAMES gawk awk)

 include_directories(${CMAKE_CURRENT_BINARY_DIR})

-if(NOT AWK OR ANDROID)
+if(NOT AWK)
  # No awk available to generate sources; use pre-built pnglibconf.h
  configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/pnglibconf.h.prebuilt
                 ${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h)
@@ -441,7 +396,7 @@ else()
    "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.chk"
    "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.out"
    "${CMAKE_CURRENT_BINARY_DIR}/scripts/vers.out")
-endif(NOT AWK OR ANDROID)
+endif(NOT AWK)

 # OUR SOURCES
 set(libpng_public_hdrs
@@ -455,7 +410,7 @@ set(libpng_private_hdrs
  pnginfo.h
  pngstruct.h
 )
-if(AWK AND NOT ANDROID)
+if(AWK)
  list(APPEND libpng_private_hdrs "${CMAKE_CURRENT_BINARY_DIR}/pngprefix.h")
 endif()
 set(libpng_sources
@@ -477,8 +432,6 @@ set(libpng_sources
  pngwtran.c
  pngwutil.c
  ${libpng_arm_sources}
-  ${libpng_intel_sources}
-  ${libpng_mips_sources}
  ${libpng_powerpc_sources}
 )
 set(pngtest_sources
@@ -755,58 +708,31 @@ if(PNG_SHARED)
  list(APPEND PNG_BIN_TARGETS png-fix-itxt)
 endif()

+# Ensure the CMAKE_LIBRARY_OUTPUT_DIRECTORY is set
+IF(NOT CMAKE_LIBRARY_OUTPUT_DIRECTORY)
+  SET(CMAKE_LIBRARY_OUTPUT_DIRECTORY "lib")
+ENDIF(NOT CMAKE_LIBRARY_OUTPUT_DIRECTORY)
+
 # Set a variable with CMake code which:
 # Creates a symlink from src to dest (if possible) or alternatively
 # copies if different.
-include(CMakeParseArguments)
-
-function(CREATE_SYMLINK DEST_FILE)
-
-  cmake_parse_arguments(S "" "FILE;TARGET" "" ${ARGN})
-
-  if(NOT S_TARGET AND NOT S_FILE)
-    message(FATAL_ERROR "Specify either a TARGET or a FILE for CREATE_SYMLINK to link to.")
-  endif(NOT S_TARGET AND NOT S_FILE)
-
-  if(S_TARGET AND S_FILE)
-    message(FATAL_ERROR "CREATE_SYMLINK called with both source file ${S_FILE} and build target ${S_TARGET} arguments - can only handle 1 type per call.")
-  endif(S_TARGET AND S_FILE)
-
-  if(S_FILE)
-    # If we don't need to symlink something that's coming from a build target,
-    # we can go ahead and symlink/copy at configure time.
-
-    if(CMAKE_HOST_WIN32 AND NOT CYGWIN AND NOT MSYS)
-      execute_process(
-	COMMAND "${CMAKE_COMMAND}" -E copy_if_different ${S_FILE} ${DEST_FILE}
-	WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}"
-	)
-    else(CMAKE_HOST_WIN32 AND NOT CYGWIN AND NOT MSYS)
-      execute_process(
-	COMMAND ${CMAKE_COMMAND} -E create_symlink ${S_FILE} ${DEST_FILE}
-	WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}"
-	)
-    endif(CMAKE_HOST_WIN32 AND NOT CYGWIN AND NOT MSYS)
-  endif(S_FILE)
-
-  if(S_TARGET)
-    # We need to use generator expressions, which can be a bit tricky, so for
-    # simplicity make the symlink a POST_BUILD step and use the TARGET
-    # signature of add_custom_command.
-
-    if(CMAKE_HOST_WIN32 AND NOT CYGWIN AND NOT MSYS)
-      add_custom_command(TARGET ${S_TARGET} POST_BUILD
-	COMMAND "${CMAKE_COMMAND}" -E copy_if_different $<TARGET_LINKER_FILE_NAME:${S_TARGET}> $<TARGET_LINKER_FILE_DIR:${S_TARGET}>/${DEST_FILE}
-	)
-    else(CMAKE_HOST_WIN32 AND NOT CYGWIN AND NOT MSYS)
-      add_custom_command(TARGET ${S_TARGET} POST_BUILD
-	COMMAND "${CMAKE_COMMAND}" -E create_symlink $<TARGET_LINKER_FILE_NAME:${S_TARGET}> $<TARGET_LINKER_FILE_DIR:${S_TARGET}>/${DEST_FILE}
-	)
-    endif(CMAKE_HOST_WIN32 AND NOT CYGWIN AND NOT MSYS)
-
-  endif(S_TARGET)
-
-endfunction()
+macro(CREATE_SYMLINK SRC_FILE DEST_FILE)
+  FILE(REMOVE ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE})
+  if(WIN32 AND NOT CYGWIN AND NOT MSYS)
+    ADD_CUSTOM_COMMAND(
+        OUTPUT ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE}   ${CMAKE_CURRENT_BINARY_DIR}/${DEST_FILE}
+        COMMAND ${CMAKE_COMMAND} -E copy_if_different  "${SRC_FILE}" ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE}
+        COMMAND ${CMAKE_COMMAND} -E copy_if_different  "${SRC_FILE}" ${CMAKE_CURRENT_BINARY_DIR}/${DEST_FILE}
+        DEPENDS ${PNG_LIB_TARGETS}
+        )
+    ADD_CUSTOM_TARGET(${DEST_FILE}_COPY ALL DEPENDS ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE})
+  else(WIN32 AND NOT CYGWIN AND NOT MSYS)
+    get_filename_component(LINK_TARGET "${SRC_FILE}" NAME)
+    execute_process(COMMAND ${CMAKE_COMMAND} -E make_directory ${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_LIBRARY_OUTPUT_DIRECTORY})
+    execute_process(COMMAND ${CMAKE_COMMAND} -E create_symlink "${LINK_TARGET}" ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE} WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})
+    execute_process(COMMAND ${CMAKE_COMMAND} -E create_symlink "${LINK_TARGET}" ${DEST_FILE} WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})
+  endif(WIN32 AND NOT CYGWIN AND NOT MSYS)
+endmacro()

 # Create source generation scripts.
 configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/genchk.cmake.in
@@ -834,17 +760,17 @@ if(NOT WIN32 OR CYGWIN OR MINGW)
  set(LIBS        "-lz -lm")
  configure_file(${CMAKE_CURRENT_SOURCE_DIR}/libpng.pc.in
    ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}.pc @ONLY)
-  CREATE_SYMLINK(libpng.pc FILE ${PNGLIB_NAME}.pc)
+  CREATE_SYMLINK(${PNGLIB_NAME}.pc libpng.pc)

  configure_file(${CMAKE_CURRENT_SOURCE_DIR}/libpng-config.in
    ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}-config @ONLY)
-  CREATE_SYMLINK(libpng-config FILE ${PNGLIB_NAME}-config)
+  CREATE_SYMLINK(${PNGLIB_NAME}-config libpng-config)
 endif(NOT WIN32 OR CYGWIN OR MINGW)

 # SET UP LINKS
 if(PNG_SHARED)
  set_target_properties(png PROPERTIES
-#   VERSION 16.${PNGLIB_RELEASE}.1.6.33
+#   VERSION 16.${PNGLIB_RELEASE}.1.6.29
    VERSION 16.${PNGLIB_RELEASE}.0
    SOVERSION 16
    CLEAN_DIRECT_OUTPUT 1)
@@ -871,20 +797,26 @@ if(NOT SKIP_INSTALL_LIBRARIES AND NOT SKIP_INSTALL_ALL )
  if(PNG_SHARED)
    # Create a symlink for libpng.dll.a => libpng16.dll.a on Cygwin
    if(CYGWIN OR MINGW)
-      CREATE_SYMLINK(libpng${CMAKE_IMPORT_LIBRARY_SUFFIX} TARGET png)
-      install(FILES $<TARGET_LINKER_FILE_DIR:png>/libpng${CMAKE_IMPORT_LIBRARY_SUFFIX} DESTINATION ${CMAKE_INSTALL_LIBDIR})
+       get_target_property(BUILD_TARGET_LOCATION png LOCATION_${CMAKE_BUILD_TYPE})
+       CREATE_SYMLINK(${BUILD_TARGET_LOCATION} libpng${CMAKE_IMPORT_LIBRARY_SUFFIX})
+       install(FILES ${CMAKE_CURRENT_BINARY_DIR}/libpng${CMAKE_IMPORT_LIBRARY_SUFFIX}
+         DESTINATION ${CMAKE_INSTALL_LIBDIR})
    endif(CYGWIN OR MINGW)

    if(NOT WIN32)
-      CREATE_SYMLINK(libpng${CMAKE_SHARED_LIBRARY_SUFFIX} TARGET png)
-      install(FILES $<TARGET_LINKER_FILE_DIR:png>/libpng${CMAKE_SHARED_LIBRARY_SUFFIX} DESTINATION ${CMAKE_INSTALL_LIBDIR})
+      get_target_property(BUILD_TARGET_LOCATION png LOCATION_${CMAKE_BUILD_TYPE})
+      CREATE_SYMLINK(${BUILD_TARGET_LOCATION} libpng${CMAKE_SHARED_LIBRARY_SUFFIX})
+      install(FILES ${CMAKE_CURRENT_BINARY_DIR}/libpng${CMAKE_SHARED_LIBRARY_SUFFIX}
+         DESTINATION ${CMAKE_INSTALL_LIBDIR})
    endif(NOT WIN32)
  endif(PNG_SHARED)

  if(PNG_STATIC)
    if(NOT WIN32 OR CYGWIN OR MINGW)
-      CREATE_SYMLINK( libpng${CMAKE_STATIC_LIBRARY_SUFFIX} TARGET png_static)
-      install(FILES $<TARGET_LINKER_FILE_DIR:png_static>/libpng${CMAKE_STATIC_LIBRARY_SUFFIX} DESTINATION ${CMAKE_INSTALL_LIBDIR})
+      get_target_property(BUILD_TARGET_LOCATION png_static LOCATION_${CMAKE_BUILD_TYPE})
+      CREATE_SYMLINK(${BUILD_TARGET_LOCATION} libpng${CMAKE_STATIC_LIBRARY_SUFFIX})
+      install(FILES ${CMAKE_CURRENT_BINARY_DIR}/libpng${CMAKE_STATIC_LIBRARY_SUFFIX}
+         DESTINATION ${CMAKE_INSTALL_LIBDIR})
    endif(NOT WIN32 OR CYGWIN OR MINGW)
 endif()
 endif()
@@ -914,7 +846,7 @@ if(NOT SKIP_INSTALL_FILES AND NOT SKIP_INSTALL_ALL )
  install(FILES libpng.3 libpngpf.3      DESTINATION ${PNG_MAN_DIR}/man3)
  install(FILES png.5                    DESTINATION ${PNG_MAN_DIR}/man5)
  # Install pkg-config files
-  if(NOT CMAKE_HOST_WIN32 OR CYGWIN OR MINGW)
+  if(NOT WIN32 OR CYGWIN OR MINGW)
    install(FILES ${CMAKE_CURRENT_BINARY_DIR}/libpng.pc
            DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig)
    install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/libpng-config
@@ -923,7 +855,7 @@ if(NOT SKIP_INSTALL_FILES AND NOT SKIP_INSTALL_ALL )
            DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig)
    install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}-config
            DESTINATION bin)
-  endif(NOT CMAKE_HOST_WIN32 OR CYGWIN OR MINGW)
+  endif(NOT WIN32 OR CYGWIN OR MINGW)
 endif()

 # On versions of CMake that support it, create an export file CMake
--- a/71
+++ b/71
@@ -16,11 +16,10 @@ Contents
      XI. Prepending a prefix to exported symbols
     XII. Configuring for compiler xxx:
    XIII. Removing unwanted object code
-     XIV. Enabling or disabling hardware optimizations
-      XV. Changes to the build and configuration of libpng in libpng-1.5.x
-     XVI. Setjmp/longjmp issues
-    XVII. Common linking failures
-   XVIII. Other sources of information about libpng
+     XIV. Changes to the build and configuration of libpng in libpng-1.5.x
+      XV. Setjmp/longjmp issues
+     XVI. Common linking failures
+    XVII. Other sources of information about libpng

 I. Simple installation

@@ -79,8 +78,8 @@ Or you can use one of the "projects" in the "projects" directory.

 Before installing libpng, you must first install zlib, if it
 is not already on your system.  zlib can usually be found
-wherever you got libpng; otherwise go to https://zlib.net/.  You can
-place zlib in the same directory as libpng or in another directory.
+wherever you got libpng; otherwise go to http://zlib.net.  You can place
+zlib in the same directory as libpng or in another directory.

 If your system already has a preinstalled zlib you will still need
 to have access to the zlib.h and zconf.h include files that
@@ -282,57 +281,7 @@ library to fail if they call functions not available in your library.
 The size of the library itself should not be an issue, because only
 those sections that are actually used will be loaded into memory.

-XIV. Enabling or disabling hardware optimizations
-
-Certain hardware capabilites, such as the Intel SSE instructions,
-are normally detected at run time. Enable them with configure options
-such as one of
-
-   --enable-arm-neon=yes
-   --enable-mips-msa=yes
-   --enable-intel-sse=yes
-   --enable-powerpc-vsx=yes
-
-or enable them all at once with
-
-   --enable-hardware-optimizations=yes
-
-or, if you are not using "configure", you can use one
-or more of
-
-   CPPFLAGS += "-DPNG_ARM_NEON"
-   CPPFLAGS += "-DPNG_MIPS_MSA"
-   CPPFLAGS += "-DPNG_INTEL_SSE"
-   CPPFLAGS += "-DPNG_POWERPC_VSX"
-
-See for example scripts/makefile.linux-opt
-
-If you wish to avoid using them,
-you can disable them via the configure option
-
-   --disable-hardware-optimizations
-
-to disable them all, or
-
-   --enable-intel-sse=no
-
-to disable a particular one,
-or via compiler-command options such as
-
-   CPPFLAGS += "-DPNG_ARM_NEON_OPT=0, -DPNG_MIPS_MSA_OPT=0,
-   -DPNG_INTEL_SSE_OPT=0, -DPNG_POWERPC_VSX_OPT=0"
-
-If you are using cmake, hardware optimizations are "on"
-by default. To disable them, use
-
-    cmake . -DPNG_ARM_NEON=no -DPNG_INTEL_SSE=no \
-            -DPNG_MIPS_MSA=no -DPNG_POWERPC_VSX=no
-
-or disable them all at once with
-
-    cmake . -DPNG_HARDWARE_OPTIMIZATIONS=no
-
-XV. Changes to the build and configuration of libpng in libpng-1.5.x
+XIV. Changes to the build and configuration of libpng in libpng-1.5.x

 Details of internal changes to the library code can be found in the CHANGES
 file and in the GIT repository logs.  These will be of no concern to the vast
@@ -423,7 +372,7 @@ $PREFIX/include directory).  Do not edit pnglibconf.h after you have built
 libpng, because than the settings would not accurately reflect the settings
 that were used to build libpng.

-XVI. Setjmp/longjmp issues
+XV. Setjmp/longjmp issues

 Libpng uses setjmp()/longjmp() for error handling.  Unfortunately setjmp()
 is known to be not thread-safe on some platforms and we don't know of
@@ -441,7 +390,7 @@ This requires setjmp/longjmp, so you must either build the library
 with PNG_SETJMP_SUPPORTED defined, or with PNG_SIMPLIFIED_READ_SUPPORTED
 and PNG_SIMPLIFIED_WRITE_SUPPORTED undefined.

-XVII. Common linking failures
+XVI. Common linking failures

 If your application fails to find libpng or zlib entries while linking:

@@ -453,7 +402,7 @@ If your application fails to find libpng or zlib entries while linking:
  If you are using the vstudio project, observe the WARNING in
  project/vstudio/README.txt.

-XVIII. Other sources of information about libpng:
+XVII. Other sources of information about libpng:

 Further information can be found in the README and libpng-manual.txt
 files, in the individual makefiles, in png.h, and the manual pages
--- a/4
+++ b/4
@@ -10,7 +10,7 @@ this sentence.

 This code is released under the libpng license.

-libpng versions 1.0.7, July 1, 2000 through 1.6.33, September 28, 2017 are
+libpng versions 1.0.7, July 1, 2000 through 1.6.29, March 16, 2017 are
 Copyright (c) 2000-2002, 2004, 2006-2017 Glenn Randers-Pehrson, are
 derived from libpng-1.0.6, and are distributed according to the same
 disclaimer and license as libpng-1.0.6 with the following individuals
@@ -130,4 +130,4 @@ any encryption software.  See the EAR, paragraphs 734.3(b)(3) and

 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-September 28, 2017
+March 16, 2017
--- a/Makefile.am
+++ b/Makefile.am
@@ -60,7 +60,6 @@ pngcp_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
 # set of parameters:
 TESTS =\
   tests/pngtest\
-   tests/pngtest-badpngs\
   tests/pngvalid-gamma-16-to-8 tests/pngvalid-gamma-alpha-mode\
   tests/pngvalid-gamma-background tests/pngvalid-gamma-expand16-alpha-mode\
   tests/pngvalid-gamma-expand16-background\
--- a/12
+++ b/12
@@ -1,4 +1,4 @@
-README for libpng version 1.6.33 - September 28, 2017 (shared library 16.0)
+README for libpng version 1.6.29 - March 16, 2017 (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.
@@ -23,7 +23,7 @@ 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 the 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
@@ -88,11 +88,11 @@ zlib should be available at the same place that libpng is, or at zlib.net.

 You may also want a copy of the PNG specification.  It is available
 as an RFC, a W3C Recommendation, and an ISO/IEC Standard.  You can find
-these at http://www.libpng.org/pub/png/pngdocs.html .
+these at http://www.libpng.org/pub/png/documents/

-This code is currently being archived at libpng.sourceforge.io in the
-[DOWNLOAD] area, and at http://libpng.download/src .  If you
-can't find it in any of those places, e-mail me, and I'll help you find it.
+This code is currently being archived at libpng.sf.net in the
+[DOWNLOAD] area, and at ftp://ftp.simplesystems.org.  If you can't find it
+in any of those places, e-mail me, and I'll help you find it.

 I am not a lawyer, but I believe that the Export Control Classification
 Number (ECCN) for libpng is EAR99, which means not subject to export
--- a/arm/filter_neon.S
+++ b/arm/filter_neon.S
@@ -1,9 +1,9 @@

 /* filter_neon.S - NEON optimised filter functions
 *
- * Copyright (c) 2014,2017 Glenn Randers-Pehrson
+ * Copyright (c) 2014 Glenn Randers-Pehrson
 * Written by Mans Rullgard, 2011.
- * Last changed in libpng 1.6.31 [July 27, 2017]
+ * 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
@@ -16,7 +16,7 @@
 #define PNG_VERSION_INFO_ONLY
 #include "../pngpriv.h"

-#if (defined(__linux__) || defined(__FreeBSD__)) && defined(__ELF__)
+#if defined(__linux__) && defined(__ELF__)
 .section .note.GNU-stack,"",%progbits /* mark stack as non-executable */
 #endif

--- a/configure.ac
+++ b/configure.ac
@@ -25,7 +25,7 @@ AC_PREREQ([2.68])

 dnl Version number stuff here:

-AC_INIT([libpng],[1.6.33],[png-mng-implement@lists.sourceforge.net])
+AC_INIT([libpng],[1.6.29],[png-mng-implement@lists.sourceforge.net])
 AC_CONFIG_MACRO_DIR([scripts])

 # libpng does not follow GNU file name conventions (hence 'foreign')
@@ -46,10 +46,10 @@ 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=1.6.33
+PNGLIB_VERSION=1.6.29
 PNGLIB_MAJOR=1
 PNGLIB_MINOR=6
-PNGLIB_RELEASE=33
+PNGLIB_RELEASE=28

 dnl End of version number stuff

@@ -300,55 +300,6 @@ AM_CONDITIONAL([DO_INSTALL_LIBPNG_CONFIG],
 # HOST SPECIFIC OPTIONS
 # =====================
 #
-# DEFAULT
-# =======
-#
-AC_ARG_ENABLE([hardware-optimizations],
-   AS_HELP_STRING([[[--enable-hardware-optimizations]]],
-      [Enable hardware optimizations: =no/off, yes/on:]),
-   [case "$enableval" in
-      no|off)
-         # disable hardware optimization on all systems:
-         enable_arm_neon=no
-         AC_DEFINE([PNG_ARM_NEON_OPT], [0],
-           [Disable ARM_NEON optimizations])
-         enable_mips_msa=no
-         AC_DEFINE([PNG_MIPS_MSA_OPT], [0],
-           [Disable MIPS_MSA optimizations])
-         enable_powerpc_vsx=no
-         AC_DEFINE([PNG_POWERPC_VSX_OPT], [0],
-           [Disable POWERPC VSX optimizations])
-         enable_intel_sse=no
-         AC_DEFINE([PNG_INTEL_SSE_OPT], [0],
-           [Disable INTEL_SSE optimizations])
-         ;;
-      *)
-         # allow enabling hardware optimization on any system:
-         case "$host_cpu" in
-            arm*|aarch64*)
-              enable_arm_neon=yes
-              AC_DEFINE([PNG_ARM_NEON_OPT], [0],
-                [Enable ARM_NEON optimizations])
-              ;;
-            mipsel*|mips64el*)
-              enable_mips_msa=yes
-              AC_DEFINE([PNG_MIPS_MSA_OPT], [0],
-                [Enable MIPS_MSA optimizations])
-              ;;
-            i?86|x86_64)
-              enable_intel_sse=yes
-              AC_DEFINE([PNG_INTEL_SSE_OPT], [1],
-                [Enable Intel SSE optimizations])
-              ;;
-            powerpc*|ppc64*)
-              enable_powerpc_vsx=yes
-              AC_DEFINE([PNG_POWERPC_VSX_OPT], [2],
-                [Enable POWERPC VSX optimizations])
-              ;;
-         esac
-         ;;
-   esac])
-
 # ARM
 # ===
 #
--- a/contrib/arm-neon/android-ndk.c
+++ b/contrib/arm-neon/android-ndk.c
@@ -17,7 +17,7 @@
 *
 * Documentation:
 *    http://www.kandroid.org/ndk/docs/CPU-ARM-NEON.html
- *    https://code.google.com/p/android/issues/detail?id=49065
+ *    http://code.google.com/p/android/issues/detail?id=49065
 *
 * NOTE: this requires that libpng is built against the Android NDK and linked
 * with an implementation of the Android ARM 'cpu-features' library.  The code
--- a/contrib/arm-neon/linux.c
+++ b/contrib/arm-neon/linux.c
@@ -1,8 +1,8 @@
 /* contrib/arm-neon/linux.c
 *
- * Last changed in libpng 1.6.31 [July 27, 2017]
- * Copyright (c) 2014, 2017 Glenn Randers-Pehrson
- * Written by John Bowler, 2014, 2017.
+ * Copyright (c) 2014 Glenn Randers-Pehrson
+ * Written by John Bowler, 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
@@ -62,7 +62,7 @@ png_have_neon(png_structp png_ptr)

               counter=0;
               state = Feature;
-               /* FALLTHROUGH */
+               /* FALL THROUGH */

            case Feature:
               /* Match 'FEATURE', ASCII case insensitive. */
@@ -75,7 +75,7 @@ png_have_neon(png_structp png_ptr)

               /* did not match 'feature' */
               state = SkipLine;
-               /* FALLTHROUGH */
+               /* FALL THROUGH */

            case SkipLine:
            skipLine:
@@ -110,7 +110,7 @@ png_have_neon(png_structp png_ptr)

               state = Neon;
               counter = 0;
-               /* FALLTHROUGH */
+               /* FALL THROUGH */

            case Neon:
               /* Look for 'neon' tag */
@@ -122,7 +122,7 @@ png_have_neon(png_structp png_ptr)
               }

               state = SkipTag;
-               /* FALLTHROUGH */
+               /* FALL THROUGH */

            case SkipTag:
               /* Skip non-space characters */
--- a/contrib/examples/pngtopng.c
+++ b/contrib/examples/pngtopng.c
@@ -5,7 +5,7 @@
 * related or neighboring rights to this work.  This work is published from:
 * United States.
 *
- * Last changed in libpng 1.6.29 [March 16, 2017]
+ * Last changed in libpng 1.6.29 [%RDATE%]
 *
 * Read a PNG and write it out in a fixed format, using the 'simplified API'
 * that was introduced in libpng-1.6.0.
--- a/contrib/gregbook/README
+++ b/contrib/gregbook/README
@@ -55,7 +55,7 @@ mation and links to the latest version of the source code, and Chapters
 13-15 of the book for detailed discussion of the three programs.

 Greg Roelofs
-https://pobox.com/~newt/greg_contact.html
+http://pobox.com/~newt/greg_contact.html
 16 March 2008


@@ -63,7 +63,7 @@ BUILD INSTRUCTIONS

 - Prerequisites (in order of compilation):

-      - zlib            https://zlib.net/
+      - zlib            http://zlib.net/
      - libpng          http://www.libpng.org/pub/png/libpng.html
      - pngbook         http://www.libpng.org/pub/png/book/sources.html

--- a/contrib/gregbook/readpng.c
+++ b/contrib/gregbook/readpng.c
@@ -4,7 +4,7 @@

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

-      Copyright (c) 1998-2007,2017 Greg Roelofs.  All rights reserved.
+      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.

      This software is provided "as is," without warranty of any kind,
      express or implied.  In no event shall the author or contributors
@@ -264,12 +264,6 @@ uch *readpng_get_image(double display_exponent, int *pChannels, ulg *pRowbytes)
    *pRowbytes = rowbytes = png_get_rowbytes(png_ptr, info_ptr);
    *pChannels = (int)png_get_channels(png_ptr, info_ptr);

-    /* Guard against integer overflow */
-    if (height > ((size_t)(-1))/rowbytes) {
-        fprintf(stderr, "readpng:  image_data buffer would be too large\n",
-        return NULL;
-    }
-
    if ((image_data = (uch *)malloc(rowbytes*height)) == NULL) {
        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
        return NULL;
--- a/contrib/gregbook/readpng2.c
+++ b/contrib/gregbook/readpng2.c
@@ -55,7 +55,6 @@

   Changelog:
     2015-11-12 - Check return value of png_get_bKGD() (Glenn R-P)
-     2017-04-22 - Guard against integer overflow (Glenn R-P)

  ---------------------------------------------------------------------------*/

--- a/contrib/gregbook/readppm.c
+++ b/contrib/gregbook/readppm.c
@@ -9,7 +9,7 @@

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

-      Copyright (c) 1998-2007,2017 Greg Roelofs.  All rights reserved.
+      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.

      This software is provided "as is," without warranty of any kind,
      express or implied.  In no event shall the author or contributors
@@ -154,18 +154,13 @@ uch *readpng_get_image(double display_exponent, int *pChannels, ulg *pRowbytes)
    *pRowbytes = rowbytes = channels*width;
    *pChannels = channels;

-    Trace((stderr, "readpng_get_image:  rowbytes = %ld, height = %ld\n", rowbytes, height));
-
-    /* Guard against integer overflow */
-    if (height > ((size_t)(-1))/rowbytes) {
-        fprintf(stderr, PROGNAME ":  image_data buffer would be too large\n",
-        return NULL;
-    }
-
    if ((image_data = (uch *)malloc(rowbytes*height)) == NULL) {
        return NULL;
    }

+    Trace((stderr, "readpng_get_image:  rowbytes = %ld, height = %ld\n", rowbytes, height));
+
+
    /* now we can go ahead and just read the whole image */

    if (fread(image_data, 1L, rowbytes*height, saved_infile) <
--- a/contrib/gregbook/rpng-win.c
+++ b/contrib/gregbook/rpng-win.c
@@ -24,11 +24,10 @@
    - 1.10:  enabled "message window"/console (thanks to David Geldreich)
    - 2.00:  dual-licensed (added GNU GPL)
    - 2.01:  fixed improper display of usage screen on PNG error(s)
-    - 2.02:  check for integer overflow (Glenn R-P)

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

-      Copyright (c) 1998-2008, 2017 Greg Roelofs.  All rights reserved.
+      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.

      This software is provided "as is," without warranty of any kind,
      express or implied.  In no event shall the author or contributors
@@ -497,12 +496,6 @@ static int rpng_win_create_window(HINSTANCE hInst, int showmode)

    wimage_rowbytes = ((3*image_width + 3L) >> 2) << 2;

-    /* Guard against integer overflow */
-    if (image_height > ((size_t)(-1))/wimage_rowbytes) {
-        fprintf(stderr, PROGNAME ":  image_data buffer would be too large\n");
-        return 4;   /* fail */
-    }
-
    if (!(dib = (uch *)malloc(sizeof(BITMAPINFOHEADER) +
                              wimage_rowbytes*image_height)))
    {
--- a/contrib/gregbook/rpng-x.c
+++ b/contrib/gregbook/rpng-x.c
@@ -28,11 +28,10 @@
    - 2.01:  fixed improper display of usage screen on PNG error(s)
    - 2.02:  Added "void(argc);" statement to quiet pedantic compiler warnings
             about unused variable (GR-P)
-    - 2.03:  check for integer overflow (Glenn R-P)

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

-      Copyright (c) 1998-2008, 2017 Greg Roelofs.  All rights reserved.
+      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.

      This software is provided "as is," without warranty of any kind,
      express or implied.  In no event shall the author or contributors
--- a/contrib/gregbook/rpng2-win.c
+++ b/contrib/gregbook/rpng2-win.c
@@ -33,11 +33,12 @@
    - 2.02:  fixed improper display of usage screen on PNG error(s); fixed
              unexpected-EOF and file-read-error cases
    - 2.03:  removed runtime MMX-enabling/disabling and obsolete -mmx* options
-    - 2.04:  check for integer overflow (Glenn R-P)
+    - 2.04:
+             (GR-P)

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

-      Copyright (c) 1998-2008, 2017 Greg Roelofs.  All rights reserved.
+      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.

      This software is provided "as is," without warranty of any kind,
      express or implied.  In no event shall the author or contributors
@@ -649,13 +650,6 @@ static void rpng2_win_init()
    Trace((stderr, "  width  = %ld\n", rpng2_info.width))
    Trace((stderr, "  height = %ld\n", rpng2_info.height))

-    /* Guard against integer overflow */
-    if (rpng2_info.height > ((size_t)(-1))/rowbytes) {
-        fprintf(stderr, PROGNAME ":  image_data buffer would be too large\n",
-        readpng2_cleanup(&rpng2_info);
-        return;
-    }
-
    rpng2_info.image_data = (uch *)malloc(rowbytes * rpng2_info.height);
    if (!rpng2_info.image_data) {
        readpng2_cleanup(&rpng2_info);
--- a/contrib/gregbook/rpng2-x.c
+++ b/contrib/gregbook/rpng2-x.c
@@ -44,11 +44,9 @@
    - 2.04:  Added "void(foo);" statements to quiet pedantic compiler warnings
             about unused variables (GR-P)
    - 2.05:  Use nanosleep() instead of usleep(), which is deprecated (GR-P).
-    - 2.06:  check for integer overflow (Glenn R-P)
  ---------------------------------------------------------------------------

-      Copyright (c) 1998-2010, 2014-2015, 2017 Greg Roelofs.  All rights
-      reserved.
+      Copyright (c) 1998-2010, 2014-2015 Greg Roelofs.  All rights reserved.

      This software is provided "as is," without warranty of any kind,
      express or implied.  In no event shall the author or contributors
@@ -782,13 +780,6 @@ static void rpng2_x_init(void)
    Trace((stderr, "  width  = %ld\n", rpng2_info.width))
    Trace((stderr, "  height = %ld\n", rpng2_info.height))

-    /* Guard against integer overflow */
-    if (rpng2_info.height > ((size_t)(-1))/rpng2_info.rowbytes) {
-        fprintf(stderr, PROGNAME ":  image_data buffer would be too large\n");
-        readpng2_cleanup(&rpng2_info);
-        return;
-    }
-
    rpng2_info.image_data = (uch *)malloc(rowbytes * rpng2_info.height);
    if (!rpng2_info.image_data) {
        readpng2_cleanup(&rpng2_info);
--- a/contrib/gregbook/wpng.c
+++ b/contrib/gregbook/wpng.c
@@ -29,7 +29,6 @@
    - 1.04:  fixed DOS/OS2/Win32 detection, including partial Cygwin fix
              (see http://home.att.net/~perlspinr/diffs/GregBook_cygwin.diff)
    - 2.00:  dual-licensed (added GNU GPL)
-    - 2.01:  check for integer overflow (Glenn R-P)

        [REPORTED BUG (win32 only):  "contrib/gregbook/wpng.c - cmd line
         dose not work!  In order to do something useful I needed to redirect
@@ -39,7 +38,7 @@

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

-      Copyright (c) 1998-2007, 2017 Greg Roelofs.  All rights reserved.
+      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.

      This software is provided "as is," without warranty of any kind,
      express or implied.  In no event shall the author or contributors
@@ -703,18 +702,7 @@ int main(int argc, char **argv)
    if (wpng_info.interlaced) {
        long i;
        ulg bytes;
-        ulg image_bytes;
-
-        /* Guard against integer overflow */
-        if (wpng_info_height > ((size_t)(-1)/rowbytes ||
-            wpng_info_height > ((ulg)(-1)/rowbytes) {
-            fprintf(stderr, PROGNAME ":  image_data buffer too large\n");
-            writepng_cleanup(&wpng_info);
-            wpng_cleanup();
-            exit(5);
-        }
-
-        image_bytes = rowbytes * wpng_info.height;
+        ulg image_bytes = rowbytes * wpng_info.height;   /* overflow? */

        wpng_info.image_data = (uch *)malloc(image_bytes);
        wpng_info.row_pointers = (uch **)malloc(wpng_info.height*sizeof(uch *));
--- a/contrib/gregbook/writepng.c
+++ b/contrib/gregbook/writepng.c
@@ -4,7 +4,7 @@

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

-      Copyright (c) 1998-2007, 2017 Greg Roelofs.  All rights reserved.
+      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.

      This software is provided "as is," without warranty of any kind,
      express or implied.  In no event shall the author or contributors
--- a/contrib/libtests/pngstest.c
+++ b/contrib/libtests/pngstest.c
@@ -1,8 +1,9 @@
 /*-
 * pngstest.c
 *
- * Last changed in libpng 1.6.31 [July 27, 2017]
- * Copyright (c) 2013-2017 John Cunningham Bowler
+ * Copyright (c) 2013-2016 John Cunningham Bowler
+ *
+ * Last changed in libpng 1.6.24 [August 4, 2016]
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
@@ -2610,9 +2611,9 @@ compare_two_images(Image *a, Image *b, int via_linear,
   const unsigned int b_sample = PNG_IMAGE_SAMPLE_SIZE(formatb);
   int alpha_added, alpha_removed;
   int bchannels;
+   int btoa[4];
   png_uint_32 y;
   Transform tr;
-   int btoa[4]={0,0,0,0};

   /* This should never happen: */
   if (width != b->image.width || height != b->image.height)
@@ -2745,27 +2746,22 @@ compare_two_images(Image *a, Image *b, int via_linear,
       */
      else if ((a->opts & ACCUMULATE) == 0)
      {
-#        ifdef __GNUC__
-#           define BYTE_CHARS 20 /* 2^32: GCC sprintf warning */
-#        else
-#           define BYTE_CHARS 3 /* 2^8: real maximum value */
-#        endif
         /* Check the original image first,
          * TODO: deal with input images with bad pixel values?
          */
         if (amax >= a->image.colormap_entries)
         {
-            char pindex[3+2*BYTE_CHARS];
-            sprintf(pindex, "%d[%u]", amax,
-               (png_byte)/*SAFE*/a->image.colormap_entries);
+            char pindex[9];
+            sprintf(pindex, "%d[%lu]", amax,
+               (unsigned long)a->image.colormap_entries);
            return logerror(a, a->file_name, ": bad pixel index: ", pindex);
         }

         else if (bmax >= b->image.colormap_entries)
         {
-            char pindex[3+2*BYTE_CHARS];
-            sprintf(pindex, "%d[%u]", bmax,
-               (png_byte)/*SAFE*/b->image.colormap_entries);
+            char pindex[9];
+            sprintf(pindex, "%d[%lu]", bmax,
+               (unsigned long)b->image.colormap_entries);
            return logerror(b, b->file_name, ": bad pixel index: ", pindex);
         }
      }
@@ -2885,13 +2881,10 @@ compare_two_images(Image *a, Image *b, int via_linear,
               {
                  case 4:
                     if (pua[btoa[3]] != pub[3]) break;
-                     /* FALLTHROUGH */
                  case 3:
                     if (pua[btoa[2]] != pub[2]) break;
-                     /* FALLTHROUGH */
                  case 2:
                     if (pua[btoa[1]] != pub[1]) break;
-                     /* FALLTHROUGH */
                  case 1:
                     if (pua[btoa[0]] != pub[0]) break;
                     if (alpha_added != 4 && pub[alpha_added] != 65535) break;
@@ -2907,13 +2900,10 @@ compare_two_images(Image *a, Image *b, int via_linear,
               {
                  case 4:
                     if (psa[btoa[3]] != psb[3]) break;
-                     /* FALLTHROUGH */
                  case 3:
                     if (psa[btoa[2]] != psb[2]) break;
-                     /* FALLTHROUGH */
                  case 2:
                     if (psa[btoa[1]] != psb[1]) break;
-                     /* FALLTHROUGH */
                  case 1:
                     if (psa[btoa[0]] != psb[0]) break;
                     if (alpha_added != 4 && psb[alpha_added] != 255) break;
--- a/contrib/libtests/pngunknown.c
+++ b/contrib/libtests/pngunknown.c
@@ -1,8 +1,8 @@

 /* pngunknown.c - test the read side unknown chunk handling
 *
- * Last changed in libpng 1.6.32 [August 24, 2017]
- * Copyright (c) 2015,2017 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.26 [October 20, 2016]
+ * Copyright (c) 2015,2016 Glenn Randers-Pehrson
 * Written by John Cunningham Bowler
 *
 * This code is released under the libpng license.
@@ -114,7 +114,6 @@ typedef png_byte *png_const_bytep;
 #define png_PLTE PNG_U32( 80,  76,  84,  69)
 #define png_bKGD PNG_U32( 98,  75,  71,  68)
 #define png_cHRM PNG_U32( 99,  72,  82,  77)
-#define png_eXIf PNG_U32(101,  88,  73, 102) /* registered July 2017 */
 #define png_fRAc PNG_U32(102,  82,  65,  99) /* registered, not defined */
 #define png_gAMA PNG_U32(103,  65,  77,  65)
 #define png_gIFg PNG_U32(103,  73,  70, 103)
@@ -211,13 +210,6 @@ static struct
         1,
 #     endif
      1,  START, 0 },
-   { "eXIf", PNG_INFO_eXIf, png_eXIf,
-#     ifdef PNG_READ_eXIf_SUPPORTED
-         0,
-#     else
-         1,
-#     endif
-      1,  END, 0 },
   { "gAMA", PNG_INFO_gAMA, png_gAMA,
 #     ifdef PNG_READ_gAMA_SUPPORTED
         0,
@@ -622,7 +614,7 @@ get_unknown(display *d, png_infop info_ptr, int after_IDAT)
                  ++(d->error_count);
                  break;
               }
-               /* FALLTHROUGH */ /* (safe) */
+               /* FALL THROUGH (safe) */
            case PNG_HANDLE_CHUNK_ALWAYS:
               break;
         }
@@ -1098,7 +1090,7 @@ static const char *standard_tests[] =
 "sTER", "sTER=if-safe", 0,
 "IDAT", "default=discard", "IDAT=save", 0,
 "sAPI", "bKGD=save", "cHRM=save", "gAMA=save", "all=discard", "iCCP=save",
-   "sBIT=save", "sRGB=save", "eXIf=save", 0,
+   "sBIT=save", "sRGB=save", 0,
 0/*end*/
 };

--- 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 1.6.31 [July 27, 2017]
+ * Last changed in libpng 1.6.29 [March 16, 2017]
 * Copyright (c) 2014-2017 John Cunningham Bowler
 *
 * This code is released under the libpng license.
@@ -6584,16 +6584,16 @@ transform_info_imp(transform_display *dp, png_structp pp, png_infop pi)
   {
   case PNG_COLOR_TYPE_PALETTE:
      if (dp->output_bit_depth > 8) goto error;
-      /* FALLTHROUGH */
+      /*FALL THROUGH*/
   case PNG_COLOR_TYPE_GRAY:
      if (dp->output_bit_depth == 1 || dp->output_bit_depth == 2 ||
         dp->output_bit_depth == 4)
         break;
-      /* FALLTHROUGH */
+      /*FALL THROUGH*/
   default:
      if (dp->output_bit_depth == 8 || dp->output_bit_depth == 16)
         break;
-      /* FALLTHROUGH */
+      /*FALL THROUGH*/
   error:
      {
         char message[128];
@@ -9994,9 +9994,9 @@ gamma_component_validate(const char *name, const validate_info *vi,
               case PNG_BACKGROUND_GAMMA_FILE:
               case PNG_BACKGROUND_GAMMA_UNIQUE:
                  use_background = (alpha >= 0 && alpha < 1);
+                  /*FALL THROUGH*/
 #           endif
 #           ifdef PNG_READ_ALPHA_MODE_SUPPORTED
-               /* FALLTHROUGH */
               case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
               case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
               case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
--- a/contrib/oss-fuzz/Dockerfile
+++ b/contrib/oss-fuzz/Dockerfile
@@ -1,24 +0,0 @@
-# Copyright 2016 Google Inc.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#      http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-#
-################################################################################
-
-FROM gcr.io/oss-fuzz-base/base-builder
-MAINTAINER glennrp@gmail.com
-RUN apt-get update && apt-get install -y make autoconf automake libtool zlib1g-dev
-
-RUN git clone --depth 1 https://github.com/glennrp/libpng.git
-RUN (cd libpng; git log | head -1)
-WORKDIR libpng
-COPY build.sh $SRC/
--- a/contrib/oss-fuzz/README.txt
+++ b/contrib/oss-fuzz/README.txt
@@ -1,37 +0,0 @@
-Last changed in libpng 1.6.33 [September 28, 2017]
-Copyright (c) 2017 Glenn Randers-Pehrson
-
-This code is released under the libpng license.
-For conditions of distribution and use, see the disclaimer
-and license in png.h
-
-Files in this directory are used by the oss-fuzz project
-(https://github.com/google/oss-fuzz/tree/master/projects/libpng).
-for "fuzzing" libpng.
-
-They were licensed by Google Inc, using the BSD-like Chromium license,
-which may be found at https://cs.chromium.org/chromium/src/LICENSE, or, if
-noted in the source, under the Apache-2.0 license, which may
-be found at http://www.apache.org/licenses/LICENSE-2.0 .
-If they have been modified, the derivatives are copyright Glenn Randers-Pehrson
-and are released under the same licenses as the originals.  Several of
-the original files (libpng_read_fuzzer.options, png.dict, project.yaml)
-had no licensing information; we assumed that these were under the Chromium
-license. Any new files are released under the libpng license (see png.h).
-
-The files are
-                            Original
- Filename                   or derived   Copyright          License
- =========================  ==========   ================   ==========
- Dockerfile*                derived      2017, Glenn R-P    Apache 2.0
- build.sh*                  derived      2017, Glenn R-P    Apache 2.0
- libpng_read_fuzzer.cc      derived      2017, Glenn R-P    Chromium
- libpng_read_fuzzer.options original     2015, Chrome Devs  Chromium
- png.dict                   original     2015, Chrome Devs  Chromium
- README.txt (this file)     original     2017, Glenn R-P    libpng
-
- * Dockerfile and build.sh are copies of the files used by oss-fuzz.
-   png.dict and libpng_read_fuzzer.* are the actual files used by oss-fuzz,
-   which retrieves them from the libpng repository at Github.
-
-To do: exercise the progressive reader and the png encoder.
--- a/contrib/oss-fuzz/build.sh
+++ b/contrib/oss-fuzz/build.sh
@@ -1,50 +0,0 @@
-#!/bin/bash -eu
-# Copyright 2017 Glenn Randers-Pehrson
-# Copyright 2016 Google Inc.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#      http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-#
-# Last changed in libpng 1.6.33 [September 28, 2017]
-#
-# Revisions by Glenn Randers-Pehson, 2017:
-# 1. Build only the library, not the tools (changed "make -j$(nproc) all" to
-#     "make -j$(nproc) libpng16.la").
-# 2. Disabled WARNING and WRITE options in pnglibconf.dfa.
-################################################################################
-
-# Disable logging via library build configuration control.
-cat scripts/pnglibconf.dfa | \
-  sed -e "s/option STDIO/option STDIO disabled/" \
-      -e "s/option WARNING /option WARNING disabled/" \
-      -e "s/option WRITE enables WRITE_INT_FUNCTIONS/option WRITE disabled/" \
-> scripts/pnglibconf.dfa.temp
-mv scripts/pnglibconf.dfa.temp scripts/pnglibconf.dfa
-
-# build the library.
-autoreconf -f -i
-./configure
-make -j$(nproc) clean
-make -j$(nproc) libpng16.la
-
-# build libpng_read_fuzzer.
-$CXX $CXXFLAGS -std=c++11 -I. \
-     $SRC/libpng/contrib/oss-fuzz/libpng_read_fuzzer.cc \
-     -o $OUT/libpng_read_fuzzer \
-     -lFuzzingEngine .libs/libpng16.a -lz
-
-# add seed corpus.
-find $SRC/libpng -name "*.png" | grep -v crashers | \
-     xargs zip $OUT/libpng_read_fuzzer_seed_corpus.zip
-
-cp $SRC/libpng/contrib/oss-fuzz/*.dict \
-     $SRC/libpng/contrib/oss-fuzz/*.options $OUT/
--- a/contrib/oss-fuzz/libpng_read_fuzzer.cc
+++ b/contrib/oss-fuzz/libpng_read_fuzzer.cc
@@ -1,180 +0,0 @@
-
-// libpng_read_fuzzer.cc
-// Copyright 2017 Glenn Randers-Pehrson
-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that may
-// be found in the LICENSE file https://cs.chromium.org/chromium/src/LICENSE
-
-// Last changed in libpng 1.6.32 [August 24, 2017]
-
-// The modifications in 2017 by Glenn Randers-Pehrson include
-// 1. addition of a PNG_CLEANUP macro,
-// 2. setting the option to ignore ADLER32 checksums,
-// 3. adding "#include <string.h>" which is needed on some platforms
-//    to provide memcpy().
-// 4. adding read_end_info() and creating an end_info structure.
-
-#include <stddef.h>
-#include <stdint.h>
-#include <string.h>
-
-#include <vector>
-
-#define PNG_INTERNAL
-#include "png.h"
-
-#define PNG_CLEANUP \
-  if(png_handler.png_ptr) \
-  { \
-    if (png_handler.row_ptr) \
-      png_free(png_handler.png_ptr, png_handler.row_ptr); \
-    if (png_handler.end_info_ptr) \
-      png_destroy_read_struct(&png_handler.png_ptr, &png_handler.info_ptr,\
-        &png_handler.end_info_ptr); \
-    else if (png_handler.info_ptr) \
-      png_destroy_read_struct(&png_handler.png_ptr, &png_handler.info_ptr,\
-        nullptr); \
-    else \
-      png_destroy_read_struct(&png_handler.png_ptr, nullptr, nullptr); \
-    png_handler.png_ptr = nullptr; \
-    png_handler.row_ptr = nullptr; \
-    png_handler.info_ptr = nullptr; \
-    png_handler.end_info_ptr = nullptr; \
-  }
-
-struct BufState {
-  const uint8_t* data;
-  size_t bytes_left;
-};
-
-struct PngObjectHandler {
-  png_infop info_ptr = nullptr;
-  png_structp png_ptr = nullptr;
-  png_infop end_info_ptr = nullptr;
-  png_voidp row_ptr = nullptr;
-  BufState* buf_state = nullptr;
-
-  ~PngObjectHandler() {
-    if (row_ptr)
-      png_free(png_ptr, row_ptr);
-    if (end_info_ptr)
-      png_destroy_read_struct(&png_ptr, &info_ptr, &end_info_ptr);
-    else if (info_ptr) 
-      png_destroy_read_struct(&png_ptr, &info_ptr, nullptr);
-    else
-      png_destroy_read_struct(&png_ptr, nullptr, nullptr);
-    delete buf_state;
-  }
-};
-
-void user_read_data(png_structp png_ptr, png_bytep data, png_size_t length) {
-  BufState* buf_state = static_cast<BufState*>(png_get_io_ptr(png_ptr));
-  if (length > buf_state->bytes_left) {
-    png_error(png_ptr, "read error");
-  }
-  memcpy(data, buf_state->data, length);
-  buf_state->bytes_left -= length;
-  buf_state->data += length;
-}
-
-static const int kPngHeaderSize = 8;
-
-// Entry point for LibFuzzer.
-// Roughly follows the libpng book example:
-// http://www.libpng.org/pub/png/book/chapter13.html
-extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
-  if (size < kPngHeaderSize) {
-    return 0;
-  }
-
-  std::vector<unsigned char> v(data, data + size);
-  if (png_sig_cmp(v.data(), 0, kPngHeaderSize)) {
-    // not a PNG.
-    return 0;
-  }
-
-  PngObjectHandler png_handler;
-  png_handler.png_ptr = nullptr;
-  png_handler.row_ptr = nullptr;
-  png_handler.info_ptr = nullptr;
-  png_handler.end_info_ptr = nullptr;
-
-  png_handler.png_ptr = png_create_read_struct
-    (PNG_LIBPNG_VER_STRING, nullptr, nullptr, nullptr);
-  if (!png_handler.png_ptr) {
-    return 0;
-  }
-
-  png_handler.info_ptr = png_create_info_struct(png_handler.png_ptr);
-  if (!png_handler.info_ptr) {
-    PNG_CLEANUP
-    return 0;
-  }
-
-  png_handler.end_info_ptr = png_create_info_struct(png_handler.png_ptr);
-  if (!png_handler.end_info_ptr) {
-    PNG_CLEANUP
-    return 0;
-  }
-
-  png_set_crc_action(png_handler.png_ptr, PNG_CRC_QUIET_USE, PNG_CRC_QUIET_USE);
-#ifdef PNG_IGNORE_ADLER32
-  png_set_option(png_handler.png_ptr, PNG_IGNORE_ADLER32, PNG_OPTION_ON);
-#endif
-
-  // Setting up reading from buffer.
-  png_handler.buf_state = new BufState();
-  png_handler.buf_state->data = data + kPngHeaderSize;
-  png_handler.buf_state->bytes_left = size - kPngHeaderSize;
-  png_set_read_fn(png_handler.png_ptr, png_handler.buf_state, user_read_data);
-  png_set_sig_bytes(png_handler.png_ptr, kPngHeaderSize);
-
-  if (setjmp(png_jmpbuf(png_handler.png_ptr))) {
-    PNG_CLEANUP
-    return 0;
-  }
-
-  // Reading.
-  png_read_info(png_handler.png_ptr, png_handler.info_ptr);
-  png_handler.row_ptr = png_malloc(
-      png_handler.png_ptr, png_get_rowbytes(png_handler.png_ptr,
-                                               png_handler.info_ptr));
-
-  // reset error handler to put png_deleter into scope.
-  if (setjmp(png_jmpbuf(png_handler.png_ptr))) {
-    PNG_CLEANUP
-    return 0;
-  }
-
-  png_uint_32 width, height;
-  int bit_depth, color_type, interlace_type, compression_type;
-  int filter_type;
-
-  if (!png_get_IHDR(png_handler.png_ptr, png_handler.info_ptr, &width,
-                    &height, &bit_depth, &color_type, &interlace_type,
-                    &compression_type, &filter_type)) {
-    PNG_CLEANUP
-    return 0;
-  }
-
-  // This is going to be too slow.
-  if (width && height > 100000000 / width) {
-    PNG_CLEANUP
-    return 0;
-  }
-
-  int passes = png_set_interlace_handling(png_handler.png_ptr);
-  png_start_read_image(png_handler.png_ptr);
-
-  for (int pass = 0; pass < passes; ++pass) {
-    for (png_uint_32 y = 0; y < height; ++y) {
-      png_read_row(png_handler.png_ptr,
-                   static_cast<png_bytep>(png_handler.row_ptr), nullptr);
-    }
-  }
-
-  png_read_end(png_handler.png_ptr, png_handler.end_info_ptr);
-
-  PNG_CLEANUP
-  return 0;
-}
--- a/contrib/oss-fuzz/libpng_read_fuzzer.options
+++ b/contrib/oss-fuzz/libpng_read_fuzzer.options
@@ -1,2 +0,0 @@
-[libfuzzer]
-dict = png.dict
--- a/contrib/oss-fuzz/newcc
+++ b/contrib/oss-fuzz/newcc
@@ -1,190 +0,0 @@
-
-// libpng_read_fuzzer.cc
-// Copyright 2017 Glenn Randers-Pehrson
-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that may
-// be found in the LICENSE file https://cs.chromium.org/chromium/src/LICENSE
-
-// Last changed in libpng 1.6.33beta03 [September 27, 2017]
-
-// The modifications in 2017 by Glenn Randers-Pehrson include
-// 1. addition of a PNG_CLEANUP macro,
-// 2. setting the option to ignore ADLER32 checksums,
-// 3. adding "#include <string.h>" which is needed on some platforms
-//    to provide memcpy().
-// 4. adding read_end_info() and creating an end_info structure.
-
-#include <stddef.h>
-#include <stdint.h>
-#include <string.h>
-
-#include <vector>
-
-#define PNG_INTERNAL
-#include "png.h"
-
-struct BufState {
-  const uint8_t* data;
-  size_t bytes_left;
-};
-
-struct PngObjectHandler {
-  png_infop info_ptr = nullptr;
-  png_structp png_ptr = nullptr;
-  png_infop end_info_ptr = nullptr;
-  png_voidp row_ptr = nullptr;
-  BufState* buf_state = nullptr;
-
-  ~PngObjectHandler() {
-    if (row_ptr)
-      png_free(png_ptr, row_ptr);
-    if (end_info_ptr)
-      png_destroy_read_struct(&png_ptr, &info_ptr, &end_info_ptr);
-    else if (info_ptr) 
-      png_destroy_read_struct(&png_ptr, &info_ptr, nullptr);
-    else
-      png_destroy_read_struct(&png_ptr, nullptr, nullptr);
-    delete buf_state;
-  }
-};
-
-void user_read_data(png_structp png_ptr, png_bytep data, png_size_t length) {
-  BufState* buf_state = static_cast<BufState*>(png_get_io_ptr(png_ptr));
-  if (length > buf_state->bytes_left) {
-    png_error(png_ptr, "read error");
-  }
-  memcpy(data, buf_state->data, length);
-  buf_state->bytes_left -= length;
-  buf_state->data += length;
-}
-
-static const int kPngHeaderSize = 8;
-
-// Entry point for LibFuzzer.
-// Roughly follows the libpng book example:
-// http://www.libpng.org/pub/png/book/chapter13.html
-
-extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
-  if (size < kPngHeaderSize) {
-    return 0;
-  }
-
-  std::vector<unsigned char> v(data, data + size);
-  if (png_sig_cmp(v.data(), 0, kPngHeaderSize)) {
-    // not a PNG.
-    return 0;
-  }
-
-  PngObjectHandler png_handler;
-  png_handler.png_ptr = nullptr;
-  png_handler.row_ptr = nullptr;
-  png_handler.info_ptr = nullptr;
-  png_handler.end_info_ptr = nullptr;
-
-  png_handler.png_ptr = png_create_read_struct
-    (PNG_LIBPNG_VER_STRING, nullptr, nullptr, nullptr);
-  if (!png_handler.png_ptr) {
-    return 0;
-  }
-
-#define PNG_CLEANUP \
-  if(png_handler.png_ptr) \
-  { \
-    if (png_handler.row_ptr) \
-      png_free(png_handler.png_ptr, png_handler.row_ptr); \
-    if (png_handler.end_info_ptr) \
-      png_destroy_read_struct(&png_handler.png_ptr, &png_handler.info_ptr,\
-        &png_handler.end_info_ptr); \
-    else if (png_handler.info_ptr) \
-      png_destroy_read_struct(&png_handler.png_ptr, &png_handler.info_ptr,\
-        nullptr); \
-    else \
-      png_destroy_read_struct(&png_handler.png_ptr, nullptr, nullptr); \
-    png_handler.png_ptr = nullptr; \
-    png_handler.row_ptr = nullptr; \
-    png_handler.info_ptr = nullptr; \
-    png_handler.end_info_ptr = nullptr; \
-  }
-
-  png_handler.info_ptr = png_create_info_struct(png_handler.png_ptr);
-  if (!png_handler.info_ptr) {
-    PNG_CLEANUP
-    return 0;
-  }
-
-  png_handler.end_info_ptr = png_create_info_struct(png_handler.png_ptr);
-  if (!png_handler.end_info_ptr) {
-    PNG_CLEANUP
-    return 0;
-  }
-
-  /* Treat benign errors as warnings */
-  png_set_benign_errors(png_handler.png_ptr, 1);
-
-  png_set_crc_action(png_handler.png_ptr, PNG_CRC_QUIET_USE, PNG_CRC_QUIET_USE);
-
-#ifdef PNG_IGNORE_ADLER32
-  png_set_option(png_handler.png_ptr, PNG_IGNORE_ADLER32, PNG_OPTION_ON);
-#endif
-
-  // Setting up reading from buffer.
-  png_handler.buf_state = new BufState();
-  png_handler.buf_state->data = data + kPngHeaderSize;
-  png_handler.buf_state->bytes_left = size - kPngHeaderSize;
-  png_set_read_fn(png_handler.png_ptr, png_handler.buf_state, user_read_data);
-  png_set_sig_bytes(png_handler.png_ptr, kPngHeaderSize);
-
-  if (setjmp(png_jmpbuf(png_handler.png_ptr))) {
-    PNG_CLEANUP
-    return 0;
-  }
-
-  // Reading.
-  png_read_info(png_handler.png_ptr, png_handler.info_ptr);
-  png_read_update_info(png_handler.png_ptr, png_handler.info_ptr);
-  png_handler.row_ptr = png_malloc(
-      png_handler.png_ptr, png_get_rowbytes(png_handler.png_ptr,
-                                               png_handler.info_ptr));
-
-  // reset error handler to put png_deleter into scope.
-  if (setjmp(png_jmpbuf(png_handler.png_ptr))) {
-    PNG_CLEANUP
-    return 0;
-  }
-
-  png_uint_32 width, height;
-  int bit_depth, color_type, interlace_type, compression_type;
-  int filter_type;
-
-  if (!png_get_IHDR(png_handler.png_ptr, png_handler.info_ptr, &width,
-                    &height, &bit_depth, &color_type, &interlace_type,
-                    &compression_type, &filter_type)) {
-    PNG_CLEANUP
-    return 0;
-  }
-
-  // This is going to be too slow.
-  if (width && height > 100000000 / width) {
-    PNG_CLEANUP
-    return 0;
-  }
-
-  int passes = png_set_interlace_handling(png_handler.png_ptr);
-  png_start_read_image(png_handler.png_ptr);
-
-  /* To do: prevent the optimizer from removing this code entirely */
-  for (int pass = 0; pass < passes; ++pass) {
-    for (png_uint_32 y = 0; y < height; ++y) {
-      png_read_row(png_handler.png_ptr,
-                   static_cast<png_bytep>(png_handler.row_ptr), nullptr);
-    }
-  }
-
-  png_read_end(png_handler.png_ptr, png_handler.end_info_ptr);
-
-  PNG_CLEANUP
-
-  /* TO do: exercise the progressive reader here */
-
-  return 0;
-}
--- a/contrib/oss-fuzz/png.dict
+++ b/contrib/oss-fuzz/png.dict
@@ -1,39 +0,0 @@
-#
-# AFL dictionary for PNG images
-# -----------------------------
-#
-# Just the basic, standard-originating sections; does not include vendor
-# extensions.
-#
-# Created by Michal Zalewski <lcamtuf@google.com>
-#
-
-header_png="\x89PNG\x0d\x0a\x1a\x0a"
-
-section_IDAT="IDAT"
-section_IEND="IEND"
-section_IHDR="IHDR"
-section_PLTE="PLTE"
-section_bKGD="bKGD"
-section_cHRM="cHRM"
-section_eXIf="eXIf"
-section_fRAc="fRAc"
-section_gAMA="gAMA"
-section_gIFg="gIFg"
-section_gIFt="gIFt"
-section_gIFx="gIFx"
-section_hIST="hIST"
-section_iCCP="iCCP"
-section_iTXt="iTXt"
-section_oFFs="oFFs"
-section_pCAL="pCAL"
-section_pHYs="pHYs"
-section_sBIT="sBIT"
-section_sCAL="sCAL"
-section_sPLT="sPLT"
-section_sRGB="sRGB"
-section_sTER="sTER"
-section_tEXt="tEXt"
-section_tIME="tIME"
-section_tRNS="tRNS"
-section_zTXt="zTXt"
--- a/contrib/pngminus/png2pnm.c
+++ b/contrib/pngminus/png2pnm.c
@@ -1,12 +1,8 @@
 /*
 *  png2pnm.c --- conversion from PNG-file to PGM/PPM-file
- *  copyright (C) 1999,2017 by Willem van Schaik <willem at schaik.com>
+ *  copyright (C) 1999 by Willem van Schaik <willem at schaik.com>
 *
 *  version 1.0 - 1999.10.15 - First version.
- *          1.1 - 2017.04.22 - Add buffer-size check (Glenn Randers-Pehrson)
- *          1.2 - 2017.08.24 - Fix potential overflow in buffer-size check
- *                             (Glenn Randers-Pehrson)
- *          1.3 - 2017.08.28 - Add PNGMINUS_UNUSED (Christian Hesse)
 *
 *  Permission to use, copy, modify, and distribute this software and
 *  its documentation for any purpose and without fee is hereby granted,
@@ -45,7 +41,6 @@
 #define PNG_DEBUG 0
 #endif

-
 #include "png.h"

 /* Define png_jmpbuf() in case we are using a pre-1.0.6 version of libpng */
@@ -53,14 +48,6 @@
 #  define png_jmpbuf(png_ptr) ((png_ptr)->jmpbuf)
 #endif

-#ifndef PNGMINUS_UNUSED
-/* Unused formal parameter warnings are silenced using the following macro
- * which is expected to have no bad effects on performance (optimizing
- * compilers will probably remove it entirely).
- */
-#  define PNGMINUS_UNUSED(param) (void)param
-#endif
-
 /* function prototypes */

 int  main (int argc, char *argv[]);
@@ -333,21 +320,14 @@ BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file,
  /* row_bytes is the width x number of channels x (bit-depth / 8) */
  row_bytes = png_get_rowbytes (png_ptr, info_ptr);

-  if ((row_bytes == 0 || (size_t)height > ((size_t)(-1))/(size_t)row_bytes))
-  {
-    /* too big */ 
-    png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
-    return FALSE;
-  }
  if ((png_pixels = (png_byte *)
-     malloc ((size_t)row_bytes * (size_t)height * sizeof (png_byte))) == NULL)
-  {
+     malloc (row_bytes * height * sizeof (png_byte))) == NULL) {
    png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
    return FALSE;
  }

  if ((row_pointers = (png_byte **)
-     malloc ((size_t)height * sizeof (png_bytep))) == NULL)
+     malloc (height * sizeof (png_bytep))) == NULL)
  {
    png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
    free (png_pixels);
@@ -428,8 +408,7 @@ BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file,
          if (raw)
            fputc ((int) *pix_ptr++ , alpha_file);
          else
-            if (bit_depth == 16)
-            {
+            if (bit_depth == 16){
              dep_16 = (long) *pix_ptr++;
              fprintf (alpha_file, "%ld ", (dep_16 << 8) + (long) *pix_ptr++);
            }
@@ -453,7 +432,6 @@ BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file,
  if (png_pixels != (unsigned char*) NULL)
    free (png_pixels);

-  PNGMINUS_UNUSED(raw); /* to quiet a Coverity defect */
  return TRUE;

 } /* end of source */
--- a/contrib/pngminus/pnm2png.c
+++ b/contrib/pngminus/pnm2png.c
@@ -1,13 +1,9 @@
 /*
 *  pnm2png.c --- conversion from PBM/PGM/PPM-file to PNG-file
- *  copyright (C) 1999,2015,2017 by Willem van Schaik <willem at schaik.com>
+ *  copyright (C) 1999 by Willem van Schaik <willem at schaik.com>
 *
 *  version 1.0 - 1999.10.15 - First version.
 *  version 1.1 - 2015.07.29 - Fixed leaks (Glenn Randers-Pehrson)
- *  version 1.2 - 2017.04.22 - Add buffer-size check
- *          1.3 - 2017.08.24 - Fix potential overflow in buffer-size check
- *                             (Glenn Randers-Pehrson)
- *          1.4 - 2017.08.28 - Add PNGMINUS_UNUSED (Christian Hesse)
 *
 *  Permission to use, copy, modify, and distribute this software and
 *  its documentation for any purpose and without fee is hereby granted,
@@ -51,15 +47,6 @@
 #  define png_jmpbuf(png_ptr) ((png_ptr)->jmpbuf)
 #endif

-#ifndef PNGMINUS_UNUSED
-/* Unused formal parameter warnings are silenced using the following macro
- * which is expected to have no bad effects on performance (optimizing
- * compilers will probably remove it entirely).
- */
-#  define PNGMINUS_UNUSED(param) (void)param
-#endif
-
-
 /* function prototypes */

 int  main (int argc, char *argv[]);
@@ -383,16 +370,11 @@ BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,
    row_bytes = (width * channels * bit_depth + 7) / 8;
  else
 #endif
-  /* row_bytes is the width x number of channels x (bit-depth / 8) */
+    /* row_bytes is the width x number of channels x (bit-depth / 8) */
    row_bytes = width * channels * ((bit_depth <= 8) ? 1 : 2);

-  if ((row_bytes == 0 || (size_t)height > ((size_t)(-1))/(size_t)row_bytes))
-  {
-    /* too big */ 
-    return FALSE;
-  }
  if ((png_pixels = (png_byte *)
-     malloc ((size_t)row_bytes * (size_t)height * sizeof (png_byte))) == NULL)
+     malloc (row_bytes * height * sizeof (png_byte))) == NULL)
    return FALSE;

  /* read data from PNM file */
@@ -401,8 +383,7 @@ BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,
  for (row = 0; row < (int) height; row++)
  {
 #if defined(PNG_WRITE_INVERT_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
-    if (packed_bitmap)
-    {
+    if (packed_bitmap) {
      for (i = 0; i < (int) row_bytes; i++)
        /* png supports this format natively so no conversion is needed */
        *pix_ptr++ = get_data (pnm_file, 8);
@@ -523,8 +504,6 @@ BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,
  if (png_pixels != (unsigned char*) NULL)
    free (png_pixels);

-  PNGMINUS_UNUSED(raw); /* Quiet a Coverity defect */
-
  return TRUE;
 } /* end of pnm2png */

@@ -541,8 +520,7 @@ void get_token(FILE *pnm_file, char *token)
  do
  {
    ret = fgetc(pnm_file);
-    if (ret == '#')
-    {
+    if (ret == '#') {
      /* the rest of this line is a comment */
      do
      {
--- a/contrib/pngsuite/README
+++ b/contrib/pngsuite/README
@@ -16,8 +16,6 @@ chunks, etc.
 The "ft*.png" images are "free/libre" replacements for the transparent
 corresponding t*.png images in the PngSuite.

-The "i*.png" images are the same complete set, but interlaced.
-
 The images in this directory represent the basic PNG color-types:
 grayscale (1-16 bit deep), full color (8 or 16 bit), paletted
 (1-8 bit) and grayscale or color images with alpha channel. You
--- a/contrib/pngsuite/ibasn0g01.png
+++ b/contrib/pngsuite/ibasn0g01.png
--- a/contrib/pngsuite/ibasn0g02.png
+++ b/contrib/pngsuite/ibasn0g02.png
--- a/contrib/pngsuite/ibasn0g04.png
+++ b/contrib/pngsuite/ibasn0g04.png
--- a/contrib/pngsuite/ibasn0g08.png
+++ b/contrib/pngsuite/ibasn0g08.png
--- a/contrib/pngsuite/ibasn0g16.png
+++ b/contrib/pngsuite/ibasn0g16.png
--- a/contrib/pngsuite/ibasn2c08.png
+++ b/contrib/pngsuite/ibasn2c08.png
--- a/contrib/pngsuite/ibasn2c16.png
+++ b/contrib/pngsuite/ibasn2c16.png
--- a/contrib/pngsuite/ibasn3p01.png
+++ b/contrib/pngsuite/ibasn3p01.png
--- a/contrib/pngsuite/ibasn3p02.png
+++ b/contrib/pngsuite/ibasn3p02.png
--- a/contrib/pngsuite/ibasn3p04.png
+++ b/contrib/pngsuite/ibasn3p04.png
--- a/contrib/pngsuite/ibasn3p08.png
+++ b/contrib/pngsuite/ibasn3p08.png
--- a/contrib/pngsuite/ibasn4a08.png
+++ b/contrib/pngsuite/ibasn4a08.png
--- a/contrib/pngsuite/ibasn4a16.png
+++ b/contrib/pngsuite/ibasn4a16.png
--- a/contrib/pngsuite/ibasn6a08.png
+++ b/contrib/pngsuite/ibasn6a08.png
--- a/contrib/pngsuite/ibasn6a16.png
+++ b/contrib/pngsuite/ibasn6a16.png
--- a/contrib/pngsuite/iftbbn0g01.png
+++ b/contrib/pngsuite/iftbbn0g01.png
--- a/contrib/pngsuite/iftbbn0g02.png
+++ b/contrib/pngsuite/iftbbn0g02.png
--- a/contrib/pngsuite/iftbbn0g04.png
+++ b/contrib/pngsuite/iftbbn0g04.png
--- a/contrib/pngsuite/iftbbn2c16.png
+++ b/contrib/pngsuite/iftbbn2c16.png
--- a/contrib/pngsuite/iftbbn3p08.png
+++ b/contrib/pngsuite/iftbbn3p08.png
--- a/contrib/pngsuite/iftbgn2c16.png
+++ b/contrib/pngsuite/iftbgn2c16.png
--- a/contrib/pngsuite/iftbgn3p08.png
+++ b/contrib/pngsuite/iftbgn3p08.png
--- a/contrib/pngsuite/iftbrn2c08.png
+++ b/contrib/pngsuite/iftbrn2c08.png
--- a/contrib/pngsuite/iftbwn0g16.png
+++ b/contrib/pngsuite/iftbwn0g16.png
--- a/contrib/pngsuite/iftbwn3p08.png
+++ b/contrib/pngsuite/iftbwn3p08.png
--- a/contrib/pngsuite/iftbyn3p08.png
+++ b/contrib/pngsuite/iftbyn3p08.png
--- a/contrib/pngsuite/iftp0n0g08.png
+++ b/contrib/pngsuite/iftp0n0g08.png
--- a/contrib/pngsuite/iftp0n2c08.png
+++ b/contrib/pngsuite/iftp0n2c08.png
--- a/contrib/pngsuite/iftp0n3p08.png
+++ b/contrib/pngsuite/iftp0n3p08.png
--- a/contrib/pngsuite/iftp1n3p08.png
+++ b/contrib/pngsuite/iftp1n3p08.png
--- a/contrib/testpngs/crashers/bad_iCCP.png
+++ b/contrib/testpngs/crashers/bad_iCCP.png
--- a/contrib/testpngs/crashers/empty_ancillary_chunks.png
+++ b/contrib/testpngs/crashers/empty_ancillary_chunks.png
--- a/contrib/testpngs/crashers/huge_IDAT.png
+++ b/contrib/testpngs/crashers/huge_IDAT.png
--- a/contrib/testpngs/crashers/huge_bKGD_chunk.png
+++ b/contrib/testpngs/crashers/huge_bKGD_chunk.png
--- a/contrib/testpngs/crashers/huge_cHRM_chunk.png
+++ b/contrib/testpngs/crashers/huge_cHRM_chunk.png
--- a/contrib/testpngs/crashers/huge_eXIf_chunk.png
+++ b/contrib/testpngs/crashers/huge_eXIf_chunk.png
--- a/contrib/testpngs/crashers/huge_gAMA_chunk.png
+++ b/contrib/testpngs/crashers/huge_gAMA_chunk.png
--- a/contrib/testpngs/crashers/huge_hIST_chunk.png
+++ b/contrib/testpngs/crashers/huge_hIST_chunk.png
--- a/contrib/testpngs/crashers/huge_iCCP_chunk.png
+++ b/contrib/testpngs/crashers/huge_iCCP_chunk.png
--- a/contrib/testpngs/crashers/huge_iTXt_chunk.png
+++ b/contrib/testpngs/crashers/huge_iTXt_chunk.png
--- a/contrib/testpngs/crashers/huge_juNK_unsafe_to_copy.png
+++ b/contrib/testpngs/crashers/huge_juNK_unsafe_to_copy.png
--- a/contrib/testpngs/crashers/huge_juNk_safe_to_copy.png
+++ b/contrib/testpngs/crashers/huge_juNk_safe_to_copy.png
--- a/contrib/testpngs/crashers/huge_pCAL_chunk.png
+++ b/contrib/testpngs/crashers/huge_pCAL_chunk.png
--- a/contrib/testpngs/crashers/huge_pHYs_chunk.png
+++ b/contrib/testpngs/crashers/huge_pHYs_chunk.png
--- a/contrib/testpngs/crashers/huge_sCAL_chunk.png
+++ b/contrib/testpngs/crashers/huge_sCAL_chunk.png
--- a/contrib/testpngs/crashers/huge_sPLT_chunk.png
+++ b/contrib/testpngs/crashers/huge_sPLT_chunk.png
--- a/contrib/testpngs/crashers/huge_sRGB_chunk.png
+++ b/contrib/testpngs/crashers/huge_sRGB_chunk.png
--- a/contrib/testpngs/crashers/huge_sTER_chunk.png
+++ b/contrib/testpngs/crashers/huge_sTER_chunk.png
--- a/contrib/testpngs/crashers/huge_tEXt_chunk.png
+++ b/contrib/testpngs/crashers/huge_tEXt_chunk.png
--- a/contrib/testpngs/crashers/huge_tIME_chunk.png
+++ b/contrib/testpngs/crashers/huge_tIME_chunk.png
--- a/contrib/testpngs/crashers/huge_zTXt_chunk.png
+++ b/contrib/testpngs/crashers/huge_zTXt_chunk.png
--- a/contrib/testpngs/makepngs.sh
+++ b/contrib/testpngs/makepngs.sh
@@ -5,7 +5,7 @@

 # Copyright (c) 2015 John Cunningham Bowler

-# Last changed in libpng 1.6.20 [December 3, 2015]
+# Last changed in libpng 1.7.0 [(PENDING RELEASE)]

 # This code is released under the libpng license.
 # For conditions of distribution and use, see the disclaimer
--- a/contrib/tools/genpng.c
+++ b/contrib/tools/genpng.c
@@ -1,8 +1,7 @@
 /*- genpng
 *
 * COPYRIGHT: Written by John Cunningham Bowler, 2015.
- * Revised by Glenn Randers-Pehrson, 2017, to add buffer-size check.
- * To the extent possible under law, the authors have waived all copyright and
+ * To the extent possible under law, the author has waived all copyright and
 * related or neighboring rights to this work.  This work is published from:
 * United States.
 *
@@ -784,19 +783,6 @@ main(int argc, const char **argv)
         return 1;
      }

-#if 1
-     /* TO do: determine whether this guard against overflow is necessary.
-      * This comment in png.h indicates that it should be safe: "libpng will
-      * refuse to process an image where such an overflow would occur", but
-      * I don't see where the image gets rejected when the buffer is too
-      * large before the malloc is attempted.
-      */
-      if (image.height > ((size_t)(-1))/(8*image.width)) {
-         fprintf(stderr, "genpng: image buffer would be too big");
-         return 1;
-      }
-#endif
-
      /* Create the buffer: */
      buffer = malloc(PNG_IMAGE_SIZE(image));

--- a/contrib/tools/pngfix.c
+++ b/contrib/tools/pngfix.c
@@ -1,7 +1,8 @@
 /* pngfix.c
 *
- * Last changed in libpng 1.6.31 [July 27, 2017]
- * Copyright (c) 2014-2017 John Cunningham Bowler
+ * Copyright (c) 2014-2016 John Cunningham Bowler
+ *
+ * Last changed in libpng 1.6.26 [October 20, 2016]
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
@@ -2415,7 +2416,7 @@ zlib_advance(struct zlib *zlib, png_uint_32 nbytes)
                  endrc = ZLIB_TOO_FAR_BACK;
                  break;
               }
-               /* FALLTHROUGH */
+               /* FALL THROUGH */

            default:
               zlib_message(zlib, 0/*stream error*/);
@@ -2569,7 +2570,7 @@ zlib_run(struct zlib *zlib)
                  list->lengths[i] -= zlib->extra_bytes;
                  list->count = i+1;
                  zlib->idat->idat_list_tail = list;
-                  /* FALLTHROUGH */
+                  /* FALL THROUGH */

               default:
                  return rc;
@@ -2672,7 +2673,7 @@ zlib_check(struct file *file, png_uint_32 offset)
            /* Truncated stream; unrecoverable, gets converted to ZLIB_FATAL */
            zlib.z.msg = PNGZ_MSG_CAST("[truncated]");
            zlib_message(&zlib, 0/*expected*/);
-            /* FALLTHROUGH */
+            /* FALL THROUGH */

         default:
            /* Unrecoverable error; skip the chunk; a zlib_message has already
@@ -3340,7 +3341,7 @@ read_callback(png_structp png_ptr, png_bytep buffer, size_t count)
               if (file->state != STATE_IDAT && length > 0)
                  setpos(chunk);
            }
-            /* FALLTHROUGH */
+            /* FALL THROUGH */

         default:
            assert(chunk != NULL);
--- a/contrib/tools/sRGB.h
+++ b/contrib/tools/sRGB.h
@@ -14,7 +14,7 @@
 * All routines take and return a floating point value in the range
 * 0 to 1.0, doing a calculation according to the sRGB specification
 * (in fact the source of the numbers is the wikipedia article at
- * https://en.wikipedia.org/wiki/SRGB).
+ * http://en.wikipedia.org/wiki/SRGB).
 */
 static double
 sRGB_from_linear(double l)
--- a/contrib/visupng/PngFile.c
+++ b/contrib/visupng/PngFile.c
@@ -2,7 +2,7 @@
 *  PNGFILE.C -- Image File Functions
 *-------------------------------------
 *
- * Copyright 2000,2017 Willem van Schaik.
+ * Copyright 2000, Willem van Schaik.
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
@@ -236,10 +236,6 @@ BOOL PngLoadImage (PTSTR pstrFileName, png_byte **ppbImageData,
            free (pbImageData);
            pbImageData = NULL;
        }
-        if ((*piHeight) > ((size_t)(-1))/ulRowBytes) {
-        {
-            png_error(png_ptr, "Visual PNG: image is too big");
-        }
        if ((pbImageData = (png_byte *) malloc(ulRowBytes * (*piHeight)
                            * sizeof(png_byte))) == NULL)
        {
--- a/contrib/visupng/VisualPng.c
+++ b/contrib/visupng/VisualPng.c
@@ -2,7 +2,7 @@
 *  VisualPng.C -- Shows a PNG image
 *------------------------------------
 *
- * Copyright 2000,2017 Willem van Schaik.
+ * Copyright 2000, Willem van Schaik.
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
@@ -726,10 +726,6 @@ BOOL DisplayImage (HWND hwnd, BYTE **ppDib,
        pDib = NULL;
    }

-    if (cyWinSize > ((size_t)(-1))/wDIRowBytes) {
-    {
-        MessageBox (hwnd, TEXT ("Visual PNG: image is too big");
-    }
    if (!(pDib = (BYTE *) malloc (sizeof(BITMAPINFOHEADER) +
        wDIRowBytes * cyWinSize)))
    {
@@ -851,10 +847,6 @@ BOOL FillBitmap (
            cxImgPos = (cxWinSize - cxNewSize) / 2;
        }

-        if (cyNewSize > ((size_t)(-1))/(cImgChannels * cxNewSize)) {
-        {
-            MessageBox (hwnd, TEXT ("Visual PNG: stretched image is too big");
-        }
        pStretchedImage = malloc (cImgChannels * cxNewSize * cyNewSize);
        pImg = pStretchedImage;

--- a/example.c
+++ b/example.c
@@ -114,13 +114,13 @@ int main(int argc, const char **argv)

         else
         {
-            /* Calling png_image_free is optional unless the simplified API was
+            /* Calling png_free_image is optional unless the simplified API was
             * not run to completion.  In this case if there wasn't enough
             * memory for 'buffer' we didn't complete the read, so we must free
             * the image:
             */
            if (buffer == NULL)
-               png_image_free(&image);
+               png_free_image(&image);

            else
               free(buffer);
@@ -983,11 +983,6 @@ void write_png(char *file_name /* , ... other image information ... */)
   png_uint_32 k, height, width;

   /* In this example, "image" is a one-dimensional array of bytes */
-
-   /* Guard against integer overflow */
-   if (height > PNG_SIZE_MAX/(width*bytes_per_pixel)) {
-      png_error(png_ptr, "Image_data buffer would be too large");
-   }
   png_byte image[height*width*bytes_per_pixel];

   png_bytep row_pointers[height];
--- a/intel/filter_sse2_intrinsics.c
+++ b/intel/filter_sse2_intrinsics.c
@@ -5,7 +5,7 @@
 * Written by Mike Klein and Matt Sarett
 * Derived from arm/filter_neon_intrinsics.c
 *
- * Last changed in libpng 1.6.31 [July 27, 2017]
+ * Last changed in libpng 1.6.29 [March 16, 2017]
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
@@ -40,7 +40,7 @@ static __m128i load3(const void* p) {
   /* We'll load 2 bytes, then 1 byte,
    * then mask them together, and finally load into SSE.
    */
-   const png_uint_16* p01 = (png_const_uint_16p)p;
+   const png_uint_16* p01 = p;
   const png_byte*    p2  = (const png_byte*)(p01+1);

   png_uint_32 v012 = (png_uint_32)(*p01)
@@ -53,15 +53,12 @@ static void store3(void* p, __m128i v) {
    * its bottom two bytes, then its third byte.
    */
   png_uint_32 v012;
-   png_uint_16* p01;
-   png_byte*    p2;
-
   store4(&v012, v);

-   p01 = (png_uint_16p)p;
-   p2  = (png_byte*)(p01+1);
-   *p01 = (png_uint_16)v012;
-   *p2  = (png_byte)(v012 >> 16);
+   png_uint_16* p01 = p;
+   png_byte*    p2  = (png_byte*)(p01+1);
+   *p01 = v012;
+   *p2  = v012 >> 16;
 }

 void png_read_filter_row_sub3_sse2(png_row_infop row_info, png_bytep row,
@@ -71,13 +68,10 @@ void png_read_filter_row_sub3_sse2(png_row_infop row_info, png_bytep row,
    * There is no pixel to the left of the first pixel.  It's encoded directly.
    * That works with our main loop if we just say that left pixel was zero.
    */
-   png_size_t rb;
-
+   png_debug(1, "in png_read_filter_row_sub3_sse2");
   __m128i a, d = _mm_setzero_si128();

-   png_debug(1, "in png_read_filter_row_sub3_sse2");
-
-   rb = row_info->rowbytes;
+   int rb = row_info->rowbytes;
   while (rb >= 4) {
      a = d; d = load4(row);
      d = _mm_add_epi8(d, a);
@@ -94,7 +88,6 @@ void png_read_filter_row_sub3_sse2(png_row_infop row_info, png_bytep row,
      row += 3;
      rb  -= 3;
   }
-   PNG_UNUSED(prev)
 }

 void png_read_filter_row_sub4_sse2(png_row_infop row_info, png_bytep row,
@@ -104,14 +97,11 @@ void png_read_filter_row_sub4_sse2(png_row_infop row_info, png_bytep row,
    * There is no pixel to the left of the first pixel.  It's encoded directly.
    * That works with our main loop if we just say that left pixel was zero.
    */
-   png_size_t rb;
-
+   png_debug(1, "in png_read_filter_row_sub4_sse2");
   __m128i a, d = _mm_setzero_si128();

-   png_debug(1, "in png_read_filter_row_sub4_sse2");
-
-   rb = row_info->rowbytes+4;
-   while (rb > 4) {
+   int rb = row_info->rowbytes;
+   while (rb > 0) {
      a = d; d = load4(row);
      d = _mm_add_epi8(d, a);
      store4(row, d);
@@ -119,7 +109,6 @@ void png_read_filter_row_sub4_sse2(png_row_infop row_info, png_bytep row,
      row += 4;
      rb  -= 4;
   }
-   PNG_UNUSED(prev)
 }

 void png_read_filter_row_avg3_sse2(png_row_infop row_info, png_bytep row,
@@ -130,23 +119,18 @@ void png_read_filter_row_avg3_sse2(png_row_infop row_info, png_bytep row,
    * predicted to be half of the pixel above it.  So again, this works
    * perfectly with our loop if we make sure a starts at zero.
    */
-
-   png_size_t rb;
-
+   png_debug(1, "in png_read_filter_row_avg3_sse2");
   const __m128i zero = _mm_setzero_si128();
-
   __m128i    b;
   __m128i a, d = zero;

-   png_debug(1, "in png_read_filter_row_avg3_sse2");
-   rb = row_info->rowbytes;
+   int rb = row_info->rowbytes;
   while (rb >= 4) {
-      __m128i avg;
             b = load4(prev);
      a = d; d = load4(row );

      /* PNG requires a truncating average, so we can't just use _mm_avg_epu8 */
-      avg = _mm_avg_epu8(a,b);
+      __m128i avg = _mm_avg_epu8(a,b);
      /* ...but we can fix it up by subtracting off 1 if it rounded up. */
      avg = _mm_sub_epi8(avg, _mm_and_si128(_mm_xor_si128(a,b),
                                            _mm_set1_epi8(1)));
@@ -158,12 +142,11 @@ void png_read_filter_row_avg3_sse2(png_row_infop row_info, png_bytep row,
      rb   -= 3;
   }
   if (rb > 0) {
-      __m128i avg;
             b = load3(prev);
      a = d; d = load3(row );

      /* PNG requires a truncating average, so we can't just use _mm_avg_epu8 */
-      avg = _mm_avg_epu8(a,b);
+      __m128i avg = _mm_avg_epu8(a,b);
      /* ...but we can fix it up by subtracting off 1 if it rounded up. */
      avg = _mm_sub_epi8(avg, _mm_and_si128(_mm_xor_si128(a,b),
                                            _mm_set1_epi8(1)));
@@ -185,21 +168,18 @@ void png_read_filter_row_avg4_sse2(png_row_infop row_info, png_bytep row,
    * predicted to be half of the pixel above it.  So again, this works
    * perfectly with our loop if we make sure a starts at zero.
    */
-   png_size_t rb;
+   png_debug(1, "in png_read_filter_row_avg4_sse2");
   const __m128i zero = _mm_setzero_si128();
   __m128i    b;
   __m128i a, d = zero;

-   png_debug(1, "in png_read_filter_row_avg4_sse2");
-
-   rb = row_info->rowbytes+4;
-   while (rb > 4) {
-      __m128i avg;
+   int rb = row_info->rowbytes;
+   while (rb > 0) {
             b = load4(prev);
      a = d; d = load4(row );

      /* PNG requires a truncating average, so we can't just use _mm_avg_epu8 */
-      avg = _mm_avg_epu8(a,b);
+      __m128i avg = _mm_avg_epu8(a,b);
      /* ...but we can fix it up by subtracting off 1 if it rounded up. */
      avg = _mm_sub_epi8(avg, _mm_and_si128(_mm_xor_si128(a,b),
                                            _mm_set1_epi8(1)));
@@ -257,42 +237,38 @@ void png_read_filter_row_paeth3_sse2(png_row_infop row_info, png_bytep row,
    * Here we zero b and d, which become c and a respectively at the start of
    * the loop.
    */
-   png_size_t rb;
+   png_debug(1, "in png_read_filter_row_paeth3_sse2");
   const __m128i zero = _mm_setzero_si128();
   __m128i c, b = zero,
           a, d = zero;

-   png_debug(1, "in png_read_filter_row_paeth3_sse2");
-
-   rb = row_info->rowbytes;
+   int rb = row_info->rowbytes;
   while (rb >= 4) {
      /* It's easiest to do this math (particularly, deal with pc) with 16-bit
       * intermediates.
       */
-      __m128i pa,pb,pc,smallest,nearest;
      c = b; b = _mm_unpacklo_epi8(load4(prev), zero);
      a = d; d = _mm_unpacklo_epi8(load4(row ), zero);

      /* (p-a) == (a+b-c - a) == (b-c) */
-   
-      pa = _mm_sub_epi16(b,c);
+      __m128i pa = _mm_sub_epi16(b,c);

      /* (p-b) == (a+b-c - b) == (a-c) */
-      pb = _mm_sub_epi16(a,c);
+      __m128i pb = _mm_sub_epi16(a,c);

      /* (p-c) == (a+b-c - c) == (a+b-c-c) == (b-c)+(a-c) */
-      pc = _mm_add_epi16(pa,pb);
+      __m128i pc = _mm_add_epi16(pa,pb);

      pa = abs_i16(pa);  /* |p-a| */
      pb = abs_i16(pb);  /* |p-b| */
      pc = abs_i16(pc);  /* |p-c| */

-      smallest = _mm_min_epi16(pc, _mm_min_epi16(pa, pb));
+      __m128i smallest = _mm_min_epi16(pc, _mm_min_epi16(pa, pb));

      /* Paeth breaks ties favoring a over b over c. */
-      nearest  = if_then_else(_mm_cmpeq_epi16(smallest, pa), a,
-                 if_then_else(_mm_cmpeq_epi16(smallest, pb), b,
-                                                             c));
+      __m128i nearest  = if_then_else(_mm_cmpeq_epi16(smallest, pa), a,
+                         if_then_else(_mm_cmpeq_epi16(smallest, pb), b,
+                                                                     c));

      /* Note `_epi8`: we need addition to wrap modulo 255. */
      d = _mm_add_epi8(d, nearest);
@@ -306,27 +282,26 @@ void png_read_filter_row_paeth3_sse2(png_row_infop row_info, png_bytep row,
      /* It's easiest to do this math (particularly, deal with pc) with 16-bit
       * intermediates.
       */
-      __m128i pa,pb,pc,smallest,nearest;
      c = b; b = _mm_unpacklo_epi8(load3(prev), zero);
      a = d; d = _mm_unpacklo_epi8(load3(row ), zero);

      /* (p-a) == (a+b-c - a) == (b-c) */
-      pa = _mm_sub_epi16(b,c);
+      __m128i pa = _mm_sub_epi16(b,c);

      /* (p-b) == (a+b-c - b) == (a-c) */
-      pb = _mm_sub_epi16(a,c);
+      __m128i pb = _mm_sub_epi16(a,c);

      /* (p-c) == (a+b-c - c) == (a+b-c-c) == (b-c)+(a-c) */
-      pc = _mm_add_epi16(pa,pb);
+      __m128i pc = _mm_add_epi16(pa,pb);

      pa = abs_i16(pa);  /* |p-a| */
      pb = abs_i16(pb);  /* |p-b| */
      pc = abs_i16(pc);  /* |p-c| */

-      smallest = _mm_min_epi16(pc, _mm_min_epi16(pa, pb));
+      __m128i smallest = _mm_min_epi16(pc, _mm_min_epi16(pa, pb));

      /* Paeth breaks ties favoring a over b over c. */
-      nearest  = if_then_else(_mm_cmpeq_epi16(smallest, pa), a,
+      __m128i nearest  = if_then_else(_mm_cmpeq_epi16(smallest, pa), a,
                         if_then_else(_mm_cmpeq_epi16(smallest, pb), b,
                                                                     c));

@@ -356,16 +331,13 @@ void png_read_filter_row_paeth4_sse2(png_row_infop row_info, png_bytep row,
    * Here we zero b and d, which become c and a respectively at the start of
    * the loop.
    */
-   png_size_t rb;
+   png_debug(1, "in png_read_filter_row_paeth4_sse2");
   const __m128i zero = _mm_setzero_si128();
-   __m128i pa,pb,pc,smallest,nearest;
   __m128i c, b = zero,
           a, d = zero;

-   png_debug(1, "in png_read_filter_row_paeth4_sse2");
-
-   rb = row_info->rowbytes+4;
-   while (rb > 4) {
+   int rb = row_info->rowbytes;
+   while (rb > 0) {
      /* It's easiest to do this math (particularly, deal with pc) with 16-bit
       * intermediates.
       */
@@ -373,22 +345,22 @@ void png_read_filter_row_paeth4_sse2(png_row_infop row_info, png_bytep row,
      a = d; d = _mm_unpacklo_epi8(load4(row ), zero);

      /* (p-a) == (a+b-c - a) == (b-c) */
-      pa = _mm_sub_epi16(b,c);
+      __m128i pa = _mm_sub_epi16(b,c);

      /* (p-b) == (a+b-c - b) == (a-c) */
-      pb = _mm_sub_epi16(a,c);
+      __m128i pb = _mm_sub_epi16(a,c);

      /* (p-c) == (a+b-c - c) == (a+b-c-c) == (b-c)+(a-c) */
-      pc = _mm_add_epi16(pa,pb);
+      __m128i pc = _mm_add_epi16(pa,pb);

      pa = abs_i16(pa);  /* |p-a| */
      pb = abs_i16(pb);  /* |p-b| */
      pc = abs_i16(pc);  /* |p-c| */

-      smallest = _mm_min_epi16(pc, _mm_min_epi16(pa, pb));
+      __m128i smallest = _mm_min_epi16(pc, _mm_min_epi16(pa, pb));

      /* Paeth breaks ties favoring a over b over c. */
-      nearest  = if_then_else(_mm_cmpeq_epi16(smallest, pa), a,
+      __m128i nearest  = if_then_else(_mm_cmpeq_epi16(smallest, pa), a,
                         if_then_else(_mm_cmpeq_epi16(smallest, pb), b,
                                                                     c));

--- a/libpng-manual.txt
+++ b/libpng-manual.txt
@@ -1,9 +1,9 @@
 libpng-manual.txt - A description on how to use and modify libpng

- libpng version 1.6.33 - September 28, 2017
+ libpng version 1.6.29 - March 16, 2017
 Updated and distributed by Glenn Randers-Pehrson
 <glennrp at users.sourceforge.net>
- Copyright (c) 1998-2017 Glenn Randers-Pehrson
+ Copyright (c) 1998-2016 Glenn Randers-Pehrson

 This document is released under the libpng license.
 For conditions of distribution and use, see the disclaimer
@@ -11,9 +11,9 @@ libpng-manual.txt - A description on how to use and modify libpng

 Based on:

- libpng versions 0.97, January 1998, through 1.6.33 - September 28, 2017
+ libpng versions 0.97, January 1998, through 1.6.29 - March 16, 2017
 Updated and distributed by Glenn Randers-Pehrson
- Copyright (c) 1998-2017 Glenn Randers-Pehrson
+ Copyright (c) 1998-2016 Glenn Randers-Pehrson

 libpng 1.0 beta 6 - version 0.96 - May 28, 1997
 Updated and distributed by Andreas Dilger
@@ -66,17 +66,17 @@ file format in application programs.

 The PNG specification (second edition), November 2003, is available as
 a W3C Recommendation and as an ISO Standard (ISO/IEC 15948:2004 (E)) at
-<https://www.w3.org/TR/2003/REC-PNG-20031110/
+<http://www.w3.org/TR/2003/REC-PNG-20031110/
 The W3C and ISO documents have identical technical content.

 The PNG-1.2 specification is available at
-<https://png-mng.sourceforge.io/pub/png/spec/1.2/>.
+<http://png-mng.sourceforge.net/pub/png/spec/1.2/>.
 It is technically equivalent
 to the PNG specification (second edition) but has some additional material.

-The PNG-1.0 specification is available as RFC 2083
-<https://png-mng.sourceforge.io/pub/png/spec/1.0/> and as a
-W3C Recommendation <https://www.w3.org/TR/REC-png-961001>.
+The PNG-1.0 specification is available as RFC 2083 
+<http://png-mng.sourceforge.net/pub/png/spec/1.0/> and as a
+W3C Recommendation <http://www.w3.org/TR/REC-png-961001>.

 Some additional chunks are described in the special-purpose public chunks
 documents at <http://www.libpng.org/pub/png/spec/register/>
@@ -101,7 +101,7 @@ majority of the needs of its users.

 Libpng uses zlib for its compression and decompression of PNG files.
 Further information about zlib, and the latest version of zlib, can
-be found at the zlib home page, <https://zlib.net/>.
+be found at the zlib home page, <http://zlib.net/>.
 The zlib compression utility is a general purpose utility that is
 useful for more than PNG files, and can be used without libpng.
 See the documentation delivered with zlib for more details.
@@ -688,9 +688,8 @@ where 0x7fffffffL means unlimited.  You can retrieve this limit with
   chunk_cache_max = png_get_chunk_cache_max(png_ptr);

 Libpng imposes a limit of 8 Megabytes (8,000,000 bytes) on the amount of
-memory that any chunk other than IDAT can occupy, originally or when
-decompressed (prior to libpng-1.6.32 the limit was only applied to compressed
-chunks after decompression). You can change this limit with
+memory that a compressed chunk other than IDAT can occupy, when decompressed.
+You can change this limit with

   png_set_chunk_malloc_max(png_ptr, user_chunk_malloc_max);

@@ -986,17 +985,8 @@ premultiplication.

    png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);

-Choices for the alpha_mode are
-
-    PNG_ALPHA_PNG           0 /* according to the PNG standard */
-    PNG_ALPHA_STANDARD      1 /* according to Porter/Duff */
-    PNG_ALPHA_ASSOCIATED    1 /* as above; this is the normal practice */
-    PNG_ALPHA_PREMULTIPLIED 1 /* as above */
-    PNG_ALPHA_OPTIMIZED     2 /* 'PNG' for opaque pixels, else 'STANDARD' */
-    PNG_ALPHA_BROKEN        3 /* the alpha channel is gamma encoded */
-
-PNG_ALPHA_PNG is the default libpng handling of the alpha channel. It is not
-pre-multiplied into the color components. In addition the call states
+This is the default libpng handling of the alpha channel - it is not
+pre-multiplied into the color components.  In addition the call states
 that the output is for a sRGB system and causes all PNG files without gAMA
 chunks to be assumed to be encoded using sRGB.

@@ -1011,7 +1001,7 @@ early Mac systems behaved.
 This is the classic Jim Blinn approach and will work in academic
 environments where everything is done by the book.  It has the shortcoming
 of assuming that input PNG data with no gamma information is linear - this
-is unlikely to be correct unless the PNG files were generated locally.
+is unlikely to be correct unless the PNG files where generated locally.
 Most of the time the output precision will be so low as to show
 significant banding in dark areas of the image.

@@ -1200,20 +1190,7 @@ row_pointers prior to calling png_read_png() with
   png_set_rows(png_ptr, info_ptr, &row_pointers);

 Alternatively you could allocate your image in one big block and define
-row_pointers[i] to point into the proper places in your block, but first
-be sure that your platform is able to allocate such a large buffer:
-
-   /* Guard against integer overflow */
-   if (height > PNG_SIZE_MAX/(width*pixel_size)) {
-        png_error(png_ptr,"image_data buffer would be too large");
-   }
-
-   png_bytep buffer=png_malloc(png_ptr,height*width*pixel_size);
-
-   for (int i=0; i<height, i++)
-      row_pointers[i]=buffer+i*width*pixel_size;
-
-   png_set_rows(png_ptr, info_ptr, &row_pointers);
+row_pointers[i] to point into the proper places in your block.

 If you use png_set_rows(), the application is responsible for freeing
 row_pointers (and row_pointers[i], if they were separately allocated).
@@ -1340,11 +1317,6 @@ in until png_read_end() has read the chunk data following the image.
    rowbytes = png_get_rowbytes(png_ptr, info_ptr);

    rowbytes       - number of bytes needed to hold a row
-                     This value, the bit_depth, color_type,
-                     and the number of channels can change
-                     if you use transforms such as
-                     png_set_expand(). See
-                     png_read_update_info(), below.

    signature = png_get_signature(png_ptr, info_ptr);

@@ -1463,11 +1435,6 @@ png_set_rgb_to_gray()).
                     the single transparent color for
                     non-paletted images (PNG_INFO_tRNS)

-    png_get_eXIf_1(png_ptr, info_ptr, &num_exif, &exif);
-                     (PNG_INFO_eXIf)
-
-    exif           - Exif profile (array of png_byte)
-
    png_get_hIST(png_ptr, info_ptr, &hist);
                     (PNG_INFO_hIST)

@@ -2179,16 +2146,6 @@ are allocating one large chunk, you will need to build an
 array of pointers to each row, as it will be needed for some
 of the functions below.

-Be sure that your platform can allocate the buffer that you'll need.
-libpng internally checks for oversize width, but you'll need to
-do your own check for number_of_rows*width*pixel_size if you are using
-a multiple-row buffer:
-
-   /* Guard against integer overflow */
-   if (number_of_rows > PNG_SIZE_MAX/(width*pixel_size)) {
-        png_error(png_ptr,"image_data buffer would be too large");
-   }
-
 Remember: Before you call png_read_update_info(), the png_get_*()
 functions return the values corresponding to the original PNG image.
 After you call png_read_update_info the values refer to the image
@@ -2513,7 +2470,6 @@ your application instead of by libpng, you can use
             PNG_INFO_gAMA, PNG_INFO_sBIT,
             PNG_INFO_cHRM, PNG_INFO_PLTE,
             PNG_INFO_tRNS, PNG_INFO_bKGD,
-             PNG_INFO_eXIf,
             PNG_INFO_hIST, PNG_INFO_pHYs,
             PNG_INFO_oFFs, PNG_INFO_tIME,
             PNG_INFO_pCAL, PNG_INFO_sRGB,
@@ -3113,11 +3069,6 @@ width, height, bit_depth, and color_type must be the same in each call.
                     single transparent color for
                     non-paletted images (PNG_INFO_tRNS)

-    png_set_eXIf_1(png_ptr, info_ptr, num_exif, exif);
-
-    exif           - Exif profile (array of
-                     png_byte) (PNG_INFO_eXIf)
-
    png_set_hIST(png_ptr, info_ptr, hist);

    hist           - histogram of palette (array of
@@ -3873,7 +3824,7 @@ PNG_FORMAT_FLAG_LINEAR flag below.

 When the simplified API needs to convert between sRGB and linear colorspaces,
 the actual sRGB transfer curve defined in the sRGB specification (see the
-article at https://en.wikipedia.org/wiki/SRGB) is used, not the gamma=1/2.2
+article at http://en.wikipedia.org/wiki/SRGB) is used, not the gamma=1/2.2
 approximation used elsewhere in libpng.

 When an alpha channel is present it is expected to denote pixel coverage
@@ -4137,7 +4088,7 @@ READ APIs

 When the simplified API needs to convert between sRGB and linear colorspaces,
 the actual sRGB transfer curve defined in the sRGB specification (see the
-article at https://en.wikipedia.org/wiki/SRGB) is used, not the gamma=1/2.2
+article at http://en.wikipedia.org/wiki/SRGB) is used, not the gamma=1/2.2
 approximation used elsewhere in libpng.

 WRITE APIS
@@ -4295,6 +4246,8 @@ functions after png_create_*_struct() has been called by calling:
        png_voidp error_ptr, png_error_ptr error_fn,
        png_error_ptr warning_fn);

+    png_voidp error_ptr = png_get_error_ptr(png_ptr);
+
 If NULL is supplied for either error_fn or warning_fn, then the libpng
 default function will be used, calling fprintf() and/or longjmp() if a
 problem is encountered.  The replacement error functions should have
@@ -4306,11 +4259,6 @@ parameters as follows:
    void user_warning_fn(png_structp png_ptr,
        png_const_charp warning_msg);

-Then, within your user_error_fn or user_warning_fn, you can retrieve
-the error_ptr if you need it, by calling
-
-    png_voidp error_ptr = png_get_error_ptr(png_ptr);
-
 The motivation behind using setjmp() and longjmp() is the C++ throw and
 catch exception handling methods.  This makes the code much easier to write,
 as there is no need to check every return code of every function call.
@@ -4318,7 +4266,7 @@ However, there are some uncertainties about the status of local variables
 after a longjmp, so the user may want to be careful about doing anything
 after setjmp returns non-zero besides returning itself.  Consult your
 compiler documentation for more details.  For an alternative approach, you
-may wish to use the "cexcept" facility (see https://cexcept.sourceforge.io/),
+may wish to use the "cexcept" facility (see http://cexcept.sourceforge.net),
 which is illustrated in pngvalid.c and in contrib/visupng.

 Beginning in libpng-1.4.0, the png_set_benign_errors() API became available.
@@ -4546,7 +4494,7 @@ in a MNG datastream.  As a minimum, it must have the MNG 8-byte signature
 and the MHDR and MEND chunks.  Libpng does not provide support for these
 or any other MNG chunks; your application must provide its own support for
 them.  You may wish to consider using libmng (available at
-https://www.libmng.com/) instead.
+http://www.libmng.com) instead.

 VIII.  Changes to Libpng from version 0.88

@@ -4969,14 +4917,18 @@ PNG_USER_WIDTH_MAX and PNG_USER_HEIGHT_MAX, although this document said
 that it could be used to override them.  Now this function will reduce or
 increase the limits.

-Starting in libpng-1.5.22, default user limits were established. These
-can be overridden by application calls to png_set_user_limits(),
-png_set_user_chunk_cache_max(), and/or png_set_user_malloc_max().
-The limits are now
-                             max possible  default
+Starting in libpng-1.5.10, the user limits can be set en masse with the
+configuration option PNG_SAFE_LIMITS_SUPPORTED.  If this option is enabled,
+a set of "safe" limits is applied in pngpriv.h.  These can be overridden by
+application calls to png_set_user_limits(), png_set_user_chunk_cache_max(),
+and/or png_set_user_malloc_max() that increase or decrease the limits.  Also,
+in libpng-1.5.10 the default width and height limits were increased
+from 1,000,000 to 0x7fffffff (i.e., made unlimited).  Therefore, the
+limits are now
+                               default      safe
   png_user_width_max        0x7fffffff    1,000,000
   png_user_height_max       0x7fffffff    1,000,000
-   png_user_chunk_cache_max  0 (unlimited) 1000
+   png_user_chunk_cache_max  0 (unlimited)   128
   png_user_chunk_malloc_max 0 (unlimited) 8,000,000

 The png_set_option() function (and the "options" member of the png struct) was
@@ -5226,11 +5178,6 @@ is an error. Previously this requirement of the PNG specification was not
 enforced, and the palette was always limited to 256 entries. An over-length
 PLTE chunk found in an input PNG is silently truncated.

-Starting with libpng-1.6.31, the eXIf chunk is supported. Libpng does not
-attempt to decode the Exif profile; it simply returns a byte array
-containing the profile to the calling application which must do its own
-decoding.
-
 XIII.  Detecting libpng

 The png_get_io_ptr() function has been present since libpng-0.88, has never
@@ -5247,33 +5194,27 @@ control.  The git repository was built from old libpng-x.y.z.tar.gz files
 going back to version 0.70.  You can access the git repository (read only)
 at

-    https://github.com/glennrp/libpng or
-    https://git.code.sf.net/p/libpng/code.git
+    git://git.code.sf.net/p/libpng/code

-or you can browse it with a web browser at
+or you can browse it with a web browser by selecting the "code" button at

-    https://github.com/glennrp/libpng or
-    https://sourceforge.net/p/libpng/code/ci/libpng16/tree/
+    https://sourceforge.net/projects/libpng

 Patches can be sent to glennrp at users.sourceforge.net or to
 png-mng-implement at lists.sourceforge.net or you can upload them to
 the libpng bug tracker at

-    https://libpng.sourceforge.io/
-
-or as a "pull request" to
-
-    https://github.com/glennrp/libpng/pulls
+    http://libpng.sourceforge.net

 We also accept patches built from the tar or zip distributions, and
 simple verbal discriptions of bug fixes, reported either to the
 SourceForge bug tracker, to the png-mng-implement at lists.sf.net
-mailing list, as github issues, or directly to glennrp.
+mailing list, or directly to glennrp.

 XV. Coding style

 Our coding style is similar to the "Allman" style
-(See https://en.wikipedia.org/wiki/Indent_style#Allman_style), with curly
+(See http://en.wikipedia.org/wiki/Indent_style#Allman_style), with curly
 braces on separate lines:

    if (condition)
@@ -5374,7 +5315,7 @@ Prior to libpng-1.6.0 we used a "png_sizeof()" macro, formatted as
 though it were a function.

 Control keywords if, for, while, and switch are always followed by a space
-to distinguish them from function calls, which have no trailing space.
+to distinguish them from function calls, which have no trailing space. 

 We put a space after each comma and after each semicolon
 in "for" statements, and we put spaces before and after each
@@ -5400,7 +5341,7 @@ for a few type names that we inherit from zlib.h.

 We prefer "if (something != 0)" and "if (something == 0)" over
 "if (something)" and if "(!something)", respectively, and for pointers
-we prefer "if (some_pointer != NULL)" or "if (some_pointer == NULL)".
+we prefer "if (some_pointer != NULL)" or "if (some_pointer == NULL)". 

 We do not use the TAB character for indentation in the C sources.

@@ -5414,7 +5355,7 @@ 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 1.6.33 are Y2K compliant.  It is my belief that earlier
+upward through 1.6.29 are Y2K compliant.  It is my belief that earlier
 versions were also Y2K compliant.

 Libpng only has two year fields.  One is a 2-byte unsigned integer
--- a/libpng.3
+++ b/libpng.3
@@ -1,6 +1,6 @@
-.TH LIBPNG 3 "September 28, 2017"
+.TH LIBPNG 3 "March 16, 2017"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.6.33
+libpng \- Portable Network Graphics (PNG) Reference Library 1.6.29
 .SH SYNOPSIS
 \fB
 #include <png.h>\fP
@@ -97,10 +97,6 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.6.33

 \fBpng_byte png_get_header_version (png_const_structp \fIpng_ptr\fP\fB);\fP

-\fBpng_uint_32 png_get_eXIf (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fI*exif\fP\fB);\fP
-
-\fBpng_uint_32 png_get_eXIf_1 (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_unit_32 \fP\fI*num_exif\fP\fB, png_bytep \fI*exif\fP\fB);\fP
-
 \fBpng_uint_32 png_get_hIST (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_16p \fI*hist\fP\fB);\fP

 \fBpng_uint_32 png_get_iCCP (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_charpp \fP\fIname\fP\fB, int \fP\fI*compression_type\fP\fB, png_bytepp \fP\fIprofile\fP\fB, png_uint_32 \fI*proflen\fP\fB);\fP
@@ -351,10 +347,6 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.6.33

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

-\fBvoid png_set_eXIf (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fIexif\fP\fB);\fP
-
-\fBvoid png_set_eXIf_1 (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, const png_uint_32 \fP\fInum_exif\fP\fB, png_bytep \fIexif\fP\fB);\fP
-
 \fBvoid png_set_hIST (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_16p \fIhist\fP\fB);\fP

 \fBvoid png_set_iCCP (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_const_charp \fP\fIname\fP\fB, int \fP\fIcompression_type\fP\fB, png_const_bytep \fP\fIprofile\fP\fB, png_uint_32 \fIproflen\fP\fB);\fP
@@ -518,10 +510,10 @@ Following is a copy of the libpng-manual.txt file that accompanies libpng.
 .SH LIBPNG.TXT
 libpng-manual.txt - A description on how to use and modify libpng

- libpng version 1.6.33 - September 28, 2017
+ libpng version 1.6.29 - March 16, 2017
 Updated and distributed by Glenn Randers-Pehrson
 <glennrp at users.sourceforge.net>
- Copyright (c) 1998-2017 Glenn Randers-Pehrson
+ Copyright (c) 1998-2016 Glenn Randers-Pehrson

 This document is released under the libpng license.
 For conditions of distribution and use, see the disclaimer
@@ -529,9 +521,9 @@ libpng-manual.txt - A description on how to use and modify libpng

 Based on:

- libpng versions 0.97, January 1998, through 1.6.33 - September 28, 2017
+ libpng versions 0.97, January 1998, through 1.6.29 - March 16, 2017
 Updated and distributed by Glenn Randers-Pehrson
- Copyright (c) 1998-2017 Glenn Randers-Pehrson
+ Copyright (c) 1998-2016 Glenn Randers-Pehrson

 libpng 1.0 beta 6 - version 0.96 - May 28, 1997
 Updated and distributed by Andreas Dilger
@@ -584,17 +576,17 @@ file format in application programs.

 The PNG specification (second edition), November 2003, is available as
 a W3C Recommendation and as an ISO Standard (ISO/IEC 15948:2004 (E)) at
-<https://www.w3.org/TR/2003/REC-PNG-20031110/
+<http://www.w3.org/TR/2003/REC-PNG-20031110/
 The W3C and ISO documents have identical technical content.

 The PNG-1.2 specification is available at
-<https://png-mng.sourceforge.io/pub/png/spec/1.2/>.
+<http://png-mng.sourceforge.net/pub/png/spec/1.2/>.
 It is technically equivalent
 to the PNG specification (second edition) but has some additional material.

-The PNG-1.0 specification is available as RFC 2083
-<https://png-mng.sourceforge.io/pub/png/spec/1.0/> and as a
-W3C Recommendation <https://www.w3.org/TR/REC-png-961001>.
+The PNG-1.0 specification is available as RFC 2083 
+<http://png-mng.sourceforge.net/pub/png/spec/1.0/> and as a
+W3C Recommendation <http://www.w3.org/TR/REC-png-961001>.

 Some additional chunks are described in the special-purpose public chunks
 documents at <http://www.libpng.org/pub/png/spec/register/>
@@ -619,7 +611,7 @@ majority of the needs of its users.

 Libpng uses zlib for its compression and decompression of PNG files.
 Further information about zlib, and the latest version of zlib, can
-be found at the zlib home page, <https://zlib.net/>.
+be found at the zlib home page, <http://zlib.net/>.
 The zlib compression utility is a general purpose utility that is
 useful for more than PNG files, and can be used without libpng.
 See the documentation delivered with zlib for more details.
@@ -1206,9 +1198,8 @@ where 0x7fffffffL means unlimited.  You can retrieve this limit with
   chunk_cache_max = png_get_chunk_cache_max(png_ptr);

 Libpng imposes a limit of 8 Megabytes (8,000,000 bytes) on the amount of
-memory that any chunk other than IDAT can occupy, originally or when
-decompressed (prior to libpng-1.6.32 the limit was only applied to compressed
-chunks after decompression). You can change this limit with
+memory that a compressed chunk other than IDAT can occupy, when decompressed.
+You can change this limit with

   png_set_chunk_malloc_max(png_ptr, user_chunk_malloc_max);

@@ -1504,17 +1495,8 @@ premultiplication.

    png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);

-Choices for the alpha_mode are
-
-    PNG_ALPHA_PNG           0 /* according to the PNG standard */
-    PNG_ALPHA_STANDARD      1 /* according to Porter/Duff */
-    PNG_ALPHA_ASSOCIATED    1 /* as above; this is the normal practice */
-    PNG_ALPHA_PREMULTIPLIED 1 /* as above */
-    PNG_ALPHA_OPTIMIZED     2 /* 'PNG' for opaque pixels, else 'STANDARD' */
-    PNG_ALPHA_BROKEN        3 /* the alpha channel is gamma encoded */
-
-PNG_ALPHA_PNG is the default libpng handling of the alpha channel. It is not
-pre-multiplied into the color components. In addition the call states
+This is the default libpng handling of the alpha channel - it is not
+pre-multiplied into the color components.  In addition the call states
 that the output is for a sRGB system and causes all PNG files without gAMA
 chunks to be assumed to be encoded using sRGB.

@@ -1529,7 +1511,7 @@ early Mac systems behaved.
 This is the classic Jim Blinn approach and will work in academic
 environments where everything is done by the book.  It has the shortcoming
 of assuming that input PNG data with no gamma information is linear - this
-is unlikely to be correct unless the PNG files were generated locally.
+is unlikely to be correct unless the PNG files where generated locally.
 Most of the time the output precision will be so low as to show
 significant banding in dark areas of the image.

@@ -1718,20 +1700,7 @@ row_pointers prior to calling png_read_png() with
   png_set_rows(png_ptr, info_ptr, &row_pointers);

 Alternatively you could allocate your image in one big block and define
-row_pointers[i] to point into the proper places in your block, but first
-be sure that your platform is able to allocate such a large buffer:
-
-   /* Guard against integer overflow */
-   if (height > PNG_SIZE_MAX/(width*pixel_size)) {
-        png_error(png_ptr,"image_data buffer would be too large");
-   }
-
-   png_bytep buffer=png_malloc(png_ptr,height*width*pixel_size);
-
-   for (int i=0; i<height, i++)
-      row_pointers[i]=buffer+i*width*pixel_size;
-
-   png_set_rows(png_ptr, info_ptr, &row_pointers);
+row_pointers[i] to point into the proper places in your block.

 If you use png_set_rows(), the application is responsible for freeing
 row_pointers (and row_pointers[i], if they were separately allocated).
@@ -1858,11 +1827,6 @@ in until png_read_end() has read the chunk data following the image.
    rowbytes = png_get_rowbytes(png_ptr, info_ptr);

    rowbytes       - number of bytes needed to hold a row
-                     This value, the bit_depth, color_type,
-                     and the number of channels can change
-                     if you use transforms such as
-                     png_set_expand(). See
-                     png_read_update_info(), below.

    signature = png_get_signature(png_ptr, info_ptr);

@@ -1981,11 +1945,6 @@ png_set_rgb_to_gray()).
                     the single transparent color for
                     non-paletted images (PNG_INFO_tRNS)

-    png_get_eXIf_1(png_ptr, info_ptr, &num_exif, &exif);
-                     (PNG_INFO_eXIf)
-
-    exif           - Exif profile (array of png_byte)
-
    png_get_hIST(png_ptr, info_ptr, &hist);
                     (PNG_INFO_hIST)

@@ -2697,16 +2656,6 @@ are allocating one large chunk, you will need to build an
 array of pointers to each row, as it will be needed for some
 of the functions below.

-Be sure that your platform can allocate the buffer that you'll need.
-libpng internally checks for oversize width, but you'll need to
-do your own check for number_of_rows*width*pixel_size if you are using
-a multiple-row buffer:
-
-   /* Guard against integer overflow */
-   if (number_of_rows > PNG_SIZE_MAX/(width*pixel_size)) {
-        png_error(png_ptr,"image_data buffer would be too large");
-   }
-
 Remember: Before you call png_read_update_info(), the png_get_*()
 functions return the values corresponding to the original PNG image.
 After you call png_read_update_info the values refer to the image
@@ -3031,7 +2980,6 @@ your application instead of by libpng, you can use
             PNG_INFO_gAMA, PNG_INFO_sBIT,
             PNG_INFO_cHRM, PNG_INFO_PLTE,
             PNG_INFO_tRNS, PNG_INFO_bKGD,
-             PNG_INFO_eXIf,
             PNG_INFO_hIST, PNG_INFO_pHYs,
             PNG_INFO_oFFs, PNG_INFO_tIME,
             PNG_INFO_pCAL, PNG_INFO_sRGB,
@@ -3631,11 +3579,6 @@ width, height, bit_depth, and color_type must be the same in each call.
                     single transparent color for
                     non-paletted images (PNG_INFO_tRNS)

-    png_set_eXIf_1(png_ptr, info_ptr, num_exif, exif);
-
-    exif           - Exif profile (array of
-                     png_byte) (PNG_INFO_eXIf)
-
    png_set_hIST(png_ptr, info_ptr, hist);

    hist           - histogram of palette (array of
@@ -4391,7 +4334,7 @@ PNG_FORMAT_FLAG_LINEAR flag below.

 When the simplified API needs to convert between sRGB and linear colorspaces,
 the actual sRGB transfer curve defined in the sRGB specification (see the
-article at https://en.wikipedia.org/wiki/SRGB) is used, not the gamma=1/2.2
+article at http://en.wikipedia.org/wiki/SRGB) is used, not the gamma=1/2.2
 approximation used elsewhere in libpng.

 When an alpha channel is present it is expected to denote pixel coverage
@@ -4655,7 +4598,7 @@ READ APIs

 When the simplified API needs to convert between sRGB and linear colorspaces,
 the actual sRGB transfer curve defined in the sRGB specification (see the
-article at https://en.wikipedia.org/wiki/SRGB) is used, not the gamma=1/2.2
+article at http://en.wikipedia.org/wiki/SRGB) is used, not the gamma=1/2.2
 approximation used elsewhere in libpng.

 WRITE APIS
@@ -4813,6 +4756,8 @@ functions after png_create_*_struct() has been called by calling:
        png_voidp error_ptr, png_error_ptr error_fn,
        png_error_ptr warning_fn);

+    png_voidp error_ptr = png_get_error_ptr(png_ptr);
+
 If NULL is supplied for either error_fn or warning_fn, then the libpng
 default function will be used, calling fprintf() and/or longjmp() if a
 problem is encountered.  The replacement error functions should have
@@ -4824,11 +4769,6 @@ parameters as follows:
    void user_warning_fn(png_structp png_ptr,
        png_const_charp warning_msg);

-Then, within your user_error_fn or user_warning_fn, you can retrieve
-the error_ptr if you need it, by calling
-
-    png_voidp error_ptr = png_get_error_ptr(png_ptr);
-
 The motivation behind using setjmp() and longjmp() is the C++ throw and
 catch exception handling methods.  This makes the code much easier to write,
 as there is no need to check every return code of every function call.
@@ -4836,7 +4776,7 @@ However, there are some uncertainties about the status of local variables
 after a longjmp, so the user may want to be careful about doing anything
 after setjmp returns non-zero besides returning itself.  Consult your
 compiler documentation for more details.  For an alternative approach, you
-may wish to use the "cexcept" facility (see https://cexcept.sourceforge.io/),
+may wish to use the "cexcept" facility (see http://cexcept.sourceforge.net),
 which is illustrated in pngvalid.c and in contrib/visupng.

 Beginning in libpng-1.4.0, the png_set_benign_errors() API became available.
@@ -5064,7 +5004,7 @@ in a MNG datastream.  As a minimum, it must have the MNG 8-byte signature
 and the MHDR and MEND chunks.  Libpng does not provide support for these
 or any other MNG chunks; your application must provide its own support for
 them.  You may wish to consider using libmng (available at
-https://www.libmng.com/) instead.
+http://www.libmng.com) instead.

 .SH VIII.  Changes to Libpng from version 0.88

@@ -5487,14 +5427,18 @@ PNG_USER_WIDTH_MAX and PNG_USER_HEIGHT_MAX, although this document said
 that it could be used to override them.  Now this function will reduce or
 increase the limits.

-Starting in libpng-1.5.22, default user limits were established. These
-can be overridden by application calls to png_set_user_limits(),
-png_set_user_chunk_cache_max(), and/or png_set_user_malloc_max().
-The limits are now
-                             max possible  default
+Starting in libpng-1.5.10, the user limits can be set en masse with the
+configuration option PNG_SAFE_LIMITS_SUPPORTED.  If this option is enabled,
+a set of "safe" limits is applied in pngpriv.h.  These can be overridden by
+application calls to png_set_user_limits(), png_set_user_chunk_cache_max(),
+and/or png_set_user_malloc_max() that increase or decrease the limits.  Also,
+in libpng-1.5.10 the default width and height limits were increased
+from 1,000,000 to 0x7fffffff (i.e., made unlimited).  Therefore, the
+limits are now
+                               default      safe
   png_user_width_max        0x7fffffff    1,000,000
   png_user_height_max       0x7fffffff    1,000,000
-   png_user_chunk_cache_max  0 (unlimited) 1000
+   png_user_chunk_cache_max  0 (unlimited)   128
   png_user_chunk_malloc_max 0 (unlimited) 8,000,000

 The png_set_option() function (and the "options" member of the png struct) was
@@ -5744,11 +5688,6 @@ is an error. Previously this requirement of the PNG specification was not
 enforced, and the palette was always limited to 256 entries. An over-length
 PLTE chunk found in an input PNG is silently truncated.

-Starting with libpng-1.6.31, the eXIf chunk is supported. Libpng does not
-attempt to decode the Exif profile; it simply returns a byte array
-containing the profile to the calling application which must do its own
-decoding.
-
 .SH XIII.  Detecting libpng

 The png_get_io_ptr() function has been present since libpng-0.88, has never
@@ -5765,33 +5704,27 @@ control.  The git repository was built from old libpng-x.y.z.tar.gz files
 going back to version 0.70.  You can access the git repository (read only)
 at

-    https://github.com/glennrp/libpng or
-    https://git.code.sf.net/p/libpng/code.git
+    git://git.code.sf.net/p/libpng/code

-or you can browse it with a web browser at
+or you can browse it with a web browser by selecting the "code" button at

-    https://github.com/glennrp/libpng or
-    https://sourceforge.net/p/libpng/code/ci/libpng16/tree/
+    https://sourceforge.net/projects/libpng

 Patches can be sent to glennrp at users.sourceforge.net or to
 png-mng-implement at lists.sourceforge.net or you can upload them to
 the libpng bug tracker at

-    https://libpng.sourceforge.io/
-
-or as a "pull request" to
-
-    https://github.com/glennrp/libpng/pulls
+    http://libpng.sourceforge.net

 We also accept patches built from the tar or zip distributions, and
 simple verbal discriptions of bug fixes, reported either to the
 SourceForge bug tracker, to the png-mng-implement at lists.sf.net
-mailing list, as github issues, or directly to glennrp.
+mailing list, or directly to glennrp.

 .SH XV. Coding style

 Our coding style is similar to the "Allman" style
-(See https://en.wikipedia.org/wiki/Indent_style#Allman_style), with curly
+(See http://en.wikipedia.org/wiki/Indent_style#Allman_style), with curly
 braces on separate lines:

    if (condition)
@@ -5892,7 +5825,7 @@ Prior to libpng-1.6.0 we used a "png_sizeof()" macro, formatted as
 though it were a function.

 Control keywords if, for, while, and switch are always followed by a space
-to distinguish them from function calls, which have no trailing space.
+to distinguish them from function calls, which have no trailing space. 

 We put a space after each comma and after each semicolon
 in "for" statements, and we put spaces before and after each
@@ -5918,7 +5851,7 @@ for a few type names that we inherit from zlib.h.

 We prefer "if (something != 0)" and "if (something == 0)" over
 "if (something)" and if "(!something)", respectively, and for pointers
-we prefer "if (some_pointer != NULL)" or "if (some_pointer == NULL)".
+we prefer "if (some_pointer != NULL)" or "if (some_pointer == NULL)". 

 We do not use the TAB character for indentation in the C sources.

@@ -5932,7 +5865,7 @@ 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 1.6.33 are Y2K compliant.  It is my belief that earlier
+upward through 1.6.29 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
@@ -6034,7 +5967,7 @@ the first widely used release:
 ...
 1.5.28                  15    10528  15.so.15.28[.0]
 ...
- 1.6.33                  16    10633  16.so.16.33[.0]
+ 1.6.29                  16    10629  16.so.16.29[.0]

 Henceforth the source version will match the shared-library minor
 and patch numbers; the shared-library major version number will be
@@ -6051,7 +5984,7 @@ release number plus "betaNN" or "rcNN".
 .LP
 .IR libpng :
 .IP
-https://libpng.sourceforge.io/ (follow the [DOWNLOAD] link)
+http://libpng.sourceforge.net (follow the [DOWNLOAD] link)
 http://www.libpng.org/pub/png

 .LP
@@ -6061,7 +5994,7 @@ http://www.libpng.org/pub/png
 .I libpng
 or at
 .br
-https://zlib.net/
+ftp://ftp.info-zip.org/pub/infozip/zlib

 .LP
 .IR PNG specification: RFC 2083
@@ -6070,11 +6003,11 @@ https://zlib.net/
 .I libpng
 or at
 .br
-https://www.ietf.org/rfc/rfc2083.txt
+ftp://ftp.rfc-editor.org:/in-notes/rfc2083.txt
 .br
 or (as a W3C Recommendation) at
 .br
-https://www.w3.org/TR/REC-png.html
+http://www.w3.org/TR/REC-png.html

 .LP
 In the case of any inconsistency between the PNG specification
@@ -6090,7 +6023,7 @@ possible without all of you.

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

-Libpng version 1.6.33 - September 28, 2017:
+Libpng version 1.6.29 - March 16, 2017:
 Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc.
 Currently maintained by Glenn Randers-Pehrson (glennrp at users.sourceforge.net).

@@ -6115,7 +6048,7 @@ this sentence.

 This code is released under the libpng license.

-libpng versions 1.0.7, July 1, 2000 through 1.6.33, September 28, 2017 are
+libpng versions 1.0.7, July 1, 2000 through 1.6.29, March 16, 2017 are
 Copyright (c) 2000-2002, 2004, 2006-2017 Glenn Randers-Pehrson, are
 derived from libpng-1.0.6, and are distributed according to the same
 disclaimer and license as libpng-1.0.6 with the following individuals
@@ -6243,7 +6176,7 @@ files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).

 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-September 28, 2017
+March 16, 2017

 .\" end of man page

--- a/libpng.pc.in
+++ b/libpng.pc.in
@@ -6,7 +6,6 @@ includedir=@includedir@/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@
 Name: libpng
 Description: Loads and saves PNG files
 Version: @PNGLIB_VERSION@
-Requires: zlib
 Libs: -L${libdir} -lpng@PNGLIB_MAJOR@@PNGLIB_MINOR@
 Libs.private: @LIBS@
 Cflags: -I${includedir}
--- a/libpngpf.3
+++ b/libpngpf.3
@@ -1,11 +1,11 @@
-.TH LIBPNGPF 3 "April 1, 2017"
+.TH LIBPNGPF 3 "March 16, 2017"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.6.33
+libpng \- Portable Network Graphics (PNG) Reference Library 1.6.29
 (private functions)
 .SH SYNOPSIS
-\fB\fB#include \fI\fI"pngpriv.h"
+\fB#include \fI"pngpriv.h"

-\fB\fBAs of libpng version \fP\fI\fP\fI1.5.1\fP\fB\fP\fB, this section is no longer \fP\fI\fP\fImaintained\fP\fB\fP\fB, now that the private function prototypes are hidden in pngpriv.h and not accessible to applications. Look in pngpriv.h for the prototypes and a short description of each \fI\fIfunction.
+\fBAs of libpng version \fP\fI1.5.1\fP\fB, this section is no longer \fP\fImaintained\fP\fB, now that the private function prototypes are hidden in pngpriv.h and not accessible to applications. Look in pngpriv.h for the prototypes and a short description of each \fIfunction.

 .SH DESCRIPTION
 The functions previously listed here are used privately by libpng and are not
--- a/png.5
+++ b/png.5
@@ -1,4 +1,4 @@
-.TH PNG 5 "April 1, 2017"
+.TH PNG 5 "March 16, 2017"
 .SH NAME
 png \- Portable Network Graphics (PNG) format
 .SH DESCRIPTION
@@ -23,11 +23,11 @@ platforms.
 PNG specification (second edition), November 2003:
 .IP
 .br
-  <https://www.w3.org/TR/2003/REC-PNG-20031110/
+  <http://www.w3.org/TR/2003/REC-PNG-20031110/
 PNG 1.2 specification, July 1999:
 .IP
 .br
-https://png-mng.sourceforge.io/pub/png/spec/1.2/
+http://png-mng.sourceforge.net/pub/png/spec/1.2/
 .LP
 PNG 1.0 specification, October 1996:
 .IP
@@ -35,11 +35,11 @@ PNG 1.0 specification, October 1996:
 RFC 2083
 .IP
 .br
-https://www.ietf.org/rfc/rfc2083.txt
+http://www.ietf.org/rfc/rfc2083.txt
 .br
 or (as a W3C Recommendation) at
 .br
-https://www.w3.org/TR/REC-png-961001
+http://www.w3.org/TR/REC-png-961001
 .SH AUTHORS
 This man page: Glenn Randers-Pehrson
 .LP
--- a/png.c
+++ b/png.c
@@ -1,7 +1,7 @@

 /* png.c - location for general purpose libpng functions
 *
- * Last changed in libpng 1.6.33 [September 28, 2017]
+ * Last changed in libpng 1.6.29 [March 16, 2017]
 * Copyright (c) 1998-2002,2004,2006-2017 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.)
@@ -14,27 +14,7 @@
 #include "pngpriv.h"

 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef png_libpng_version_1_6_33 Your_png_h_is_not_version_1_6_33;
-
-#ifdef __GNUC__
-/* The version tests may need to be added to, but the problem warning has
- * consistently been fixed in GCC versions which obtain wide-spread release.
- * The problem is that many versions of GCC rearrange comparison expressions in
- * the optimizer in such a way that the results of the comparison will change
- * if signed integer overflow occurs.  Such comparisons are not permitted in
- * ANSI C90, however GCC isn't clever enough to work out that that do not occur
- * below in png_ascii_from_fp and png_muldiv, so it produces a warning with
- * -Wextra.  Unfortunately this is highly dependent on the optimizer and the
- * machine architecture so the warning comes and goes unpredictably and is
- * impossible to "fix", even were that a good idea.
- */
-#if __GNUC__ == 7 && __GNUC_MINOR__ == 1
-#define GCC_STRICT_OVERFLOW 1
-#endif /* GNU 7.1.x */
-#endif /* GNU */
-#ifndef GCC_STRICT_OVERFLOW
-#define GCC_STRICT_OVERFLOW 0
-#endif
+typedef png_libpng_version_1_6_29 Your_png_h_is_not_version_1_6_29;

 /* Tells libpng that we have already handled the first "num_bytes" bytes
 * of the PNG file signature.  If the PNG data is embedded into another
@@ -615,26 +595,6 @@ png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask,
   }
 #endif

-#ifdef PNG_eXIf_SUPPORTED
-   /* Free any eXIf entry */
-   if (((mask & PNG_FREE_EXIF) & info_ptr->free_me) != 0)
-   {
-# ifdef PNG_READ_eXIf_SUPPORTED
-      if (info_ptr->eXIf_buf)
-      {
-         png_free(png_ptr, info_ptr->eXIf_buf);
-         info_ptr->eXIf_buf = NULL;
-      }
-# endif
-      if (info_ptr->exif)
-      {
-         png_free(png_ptr, info_ptr->exif);
-         info_ptr->exif = NULL;
-      }
-      info_ptr->valid &= ~PNG_INFO_eXIf;
-   }
-#endif
-
 #ifdef PNG_hIST_SUPPORTED
   /* Free any hIST entry */
   if (((mask & PNG_FREE_HIST) & info_ptr->free_me) != 0)
@@ -816,14 +776,14 @@ png_get_copyright(png_const_structrp png_ptr)
 #else
 #  ifdef __STDC__
   return PNG_STRING_NEWLINE \
-      "libpng version 1.6.33 - September 28, 2017" PNG_STRING_NEWLINE \
+      "libpng version 1.6.29 - March 16, 2017" PNG_STRING_NEWLINE \
      "Copyright (c) 1998-2002,2004,2006-2017 Glenn Randers-Pehrson" \
      PNG_STRING_NEWLINE \
      "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \
      "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \
      PNG_STRING_NEWLINE;
 #  else
-   return "libpng version 1.6.33 - September 28, 2017\
+   return "libpng version 1.6.29 - March 16, 2017\
      Copyright (c) 1998-2002,2004,2006-2017 Glenn Randers-Pehrson\
      Copyright (c) 1996-1997 Andreas Dilger\
      Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.";
@@ -1913,12 +1873,12 @@ png_colorspace_set_sRGB(png_const_structrp png_ptr, png_colorspacerp colorspace,
    */
   if (intent < 0 || intent >= PNG_sRGB_INTENT_LAST)
      return png_icc_profile_error(png_ptr, colorspace, "sRGB",
-          (png_alloc_size_t)intent, "invalid sRGB rendering intent");
+          (unsigned)intent, "invalid sRGB rendering intent");

   if ((colorspace->flags & PNG_COLORSPACE_HAVE_INTENT) != 0 &&
       colorspace->rendering_intent != intent)
      return png_icc_profile_error(png_ptr, colorspace, "sRGB",
-         (png_alloc_size_t)intent, "inconsistent rendering intents");
+         (unsigned)intent, "inconsistent rendering intents");

   if ((colorspace->flags & PNG_COLORSPACE_FROM_sRGB) != 0)
   {
@@ -1979,6 +1939,7 @@ icc_check_length(png_const_structrp png_ptr, png_colorspacerp colorspace,
   if (profile_length < 132)
      return png_icc_profile_error(png_ptr, colorspace, name, profile_length,
          "too short");
+
   return 1;
 }

@@ -2223,6 +2184,15 @@ png_icc_check_tag_table(png_const_structrp png_ptr, png_colorspacerp colorspace,
       * being in range.  All defined tag types have an 8 byte header - a 4 byte
       * type signature then 0.
       */
+      if ((tag_start & 3) != 0)
+      {
+         /* CNHP730S.icc shipped with Microsoft Windows 64 violates this, it is
+          * only a warning here because libpng does not care about the
+          * alignment.
+          */
+         (void)png_icc_profile_error(png_ptr, NULL, name, tag_id,
+             "ICC profile tag start not a multiple of 4");
+      }

      /* This is a hard error; potentially it can cause read outside the
       * profile.
@@ -2230,16 +2200,6 @@ png_icc_check_tag_table(png_const_structrp png_ptr, png_colorspacerp colorspace,
      if (tag_start > profile_length || tag_length > profile_length - tag_start)
         return png_icc_profile_error(png_ptr, colorspace, name, tag_id,
             "ICC profile tag outside profile");
-
-      if ((tag_start & 3) != 0)
-      {
-         /* CNHP730S.icc shipped with Microsoft Windows 64 violates this; it is
-          * only a warning here because libpng does not care about the
-          * alignment.
-          */
-         (void)png_icc_profile_error(png_ptr, NULL, name, tag_id,
-             "ICC profile tag start not a multiple of 4");
-      }
   }

   return 1; /* success, maybe with warnings */
@@ -2872,7 +2832,7 @@ png_pow10(int power)
   if (power < 0)
   {
      if (power < DBL_MIN_10_EXP) return 0;
-      recip = 1; power = -power;
+      recip = 1, power = -power;
   }

   if (power > 0)
@@ -2897,14 +2857,6 @@ png_pow10(int power)
 /* Function to format a floating point value in ASCII with a given
 * precision.
 */
-#if GCC_STRICT_OVERFLOW
-#pragma GCC diagnostic push
-/* The problem arises below with exp_b10, which can never overflow because it
- * comes, originally, from frexp and is therefore limited to a range which is
- * typically +/-710 (log2(DBL_MAX)/log2(DBL_MIN)).
- */
-#pragma GCC diagnostic warning "-Wstrict-overflow=2"
-#endif /* GCC_STRICT_OVERFLOW */
 void /* PRIVATE */
 png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,
    double fp, unsigned int precision)
@@ -2958,9 +2910,7 @@ png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,
            double test = png_pow10(exp_b10+1);

            if (test <= DBL_MAX)
-            {
-               ++exp_b10; base = test;
-            }
+               ++exp_b10, base = test;

            else
               break;
@@ -2974,10 +2924,7 @@ png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,
          * test on DBL_MAX above.
          */
         fp /= base;
-         while (fp >= 1)
-         {
-            fp /= 10; ++exp_b10;
-         }
+         while (fp >= 1) fp /= 10, ++exp_b10;

         /* Because of the code above fp may, at this point, be
          * less than .1, this is ok because the code below can
@@ -2994,7 +2941,7 @@ png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,
             */
            if (exp_b10 < 0 && exp_b10 > -3) /* PLUS 3 TOTAL 4 */
            {
-               czero = 0U-exp_b10; /* PLUS 2 digits: TOTAL 3 */
+               czero = (unsigned int)(-exp_b10); /* PLUS 2 digits: TOTAL 3 */
               exp_b10 = 0;      /* Dot added below before first output. */
            }
            else
@@ -3028,7 +2975,7 @@ png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,
                     /* Rounding up to 10, handle that here. */
                     if (czero > 0)
                     {
-                        --czero; d = 1;
+                        --czero, d = 1;
                        if (cdigits == 0) --clead;
                     }
                     else
@@ -3042,7 +2989,7 @@ png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,

                           else if (ch == 46)
                           {
-                              ch = *--ascii; ++size;
+                              ch = *--ascii, ++size;
                              /* Advance exp_b10 to '1', so that the
                               * decimal point happens after the
                               * previous digit.
@@ -3069,9 +3016,7 @@ png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,
                              int ch = *--ascii;

                              if (ch == 46)
-                              {
-                                 ++size; exp_b10 = 1;
-                              }
+                                 ++size, exp_b10 = 1;

                              /* Else lost a leading zero, so 'exp_b10' is
                               * still ok at (-1)
@@ -3107,26 +3052,21 @@ png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,
                      */
                     if (exp_b10 != (-1))
                     {
-                        if (exp_b10 == 0)
-                        {
-                           *ascii++ = 46; --size;
-                        }
+                        if (exp_b10 == 0) *ascii++ = 46, --size;
                        /* PLUS 1: TOTAL 4 */
                        --exp_b10;
                     }
-                     *ascii++ = 48; --czero;
+                     *ascii++ = 48, --czero;
                  }

                  if (exp_b10 != (-1))
                  {
                     if (exp_b10 == 0)
-                     {
-                        *ascii++ = 46; --size; /* counted above */
-                     }
+                        *ascii++ = 46, --size; /* counted above */

                     --exp_b10;
                  }
-                  *ascii++ = (char)(48 + (int)d); ++cdigits;
+                  *ascii++ = (char)(48 + (int)d), ++cdigits;
               }
            }
            while (cdigits+czero < precision+clead && fp > DBL_MIN);
@@ -3135,7 +3075,7 @@ png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,

            /* Check for an exponent, if we don't need one we are
             * done and just need to terminate the string.  At
-             * this point exp_b10==(-1) is effectively a flag - it got
+             * this point exp_b10==(-1) is effectively if flag - it got
             * to '-1' because of the decrement after outputting
             * the decimal point above (the exponent required is
             * *not* -1!)
@@ -3149,7 +3089,7 @@ png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,
                * zeros were *not* output, so this doesn't increase
                * the output count.
                */
-               while (exp_b10-- > 0) *ascii++ = 48;
+               while (--exp_b10 >= 0) *ascii++ = 48;

               *ascii = 0;

@@ -3167,7 +3107,7 @@ png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,
             */
            size -= cdigits;

-            *ascii++ = 69; --size;    /* 'E': PLUS 1 TOTAL 2+precision */
+            *ascii++ = 69, --size;    /* 'E': PLUS 1 TOTAL 2+precision */

            /* The following use of an unsigned temporary avoids ambiguities in
             * the signed arithmetic on exp_b10 and permits GCC at least to do
@@ -3178,12 +3118,12 @@ png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,

               if (exp_b10 < 0)
               {
-                  *ascii++ = 45; --size; /* '-': PLUS 1 TOTAL 3+precision */
-                  uexp_b10 = 0U-exp_b10;
+                  *ascii++ = 45, --size; /* '-': PLUS 1 TOTAL 3+precision */
+                  uexp_b10 = (unsigned int)(-exp_b10);
               }

               else
-                  uexp_b10 = 0U+exp_b10;
+                  uexp_b10 = (unsigned int)exp_b10;

               cdigits = 0;

@@ -3226,9 +3166,6 @@ png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,
   /* Here on buffer too small. */
   png_error(png_ptr, "ASCII conversion buffer too small");
 }
-#if GCC_STRICT_OVERFLOW
-#pragma GCC diagnostic pop
-#endif /* GCC_STRICT_OVERFLOW */

 #  endif /* FLOATING_POINT */

@@ -3248,9 +3185,7 @@ png_ascii_from_fixed(png_const_structrp png_ptr, png_charp ascii,

      /* Avoid overflow here on the minimum integer. */
      if (fp < 0)
-      {
-         *ascii++ = 45; num = (png_uint_32)(-fp);
-      }
+         *ascii++ = 45, num = (png_uint_32)(-fp);
      else
         num = (png_uint_32)fp;

@@ -3288,10 +3223,7 @@ png_ascii_from_fixed(png_const_structrp png_ptr, png_charp ascii,
                * then ndigits digits to first:
                */
               i = 5;
-               while (ndigits < i)
-               {
-                  *ascii++ = 48; --i;
-               }
+               while (ndigits < i) *ascii++ = 48, --i;
               while (ndigits >= first) *ascii++ = digits[--ndigits];
               /* Don't output the trailing zeros! */
            }
@@ -3342,15 +3274,6 @@ png_fixed(png_const_structrp png_ptr, double fp, png_const_charp text)
 * the nearest .00001).  Overflow and divide by zero are signalled in
 * the result, a boolean - true on success, false on overflow.
 */
-#if GCC_STRICT_OVERFLOW /* from above */
-/* It is not obvious which comparison below gets optimized in such a way that
- * signed overflow would change the result; looking through the code does not
- * reveal any tests which have the form GCC complains about, so presumably the
- * optimizer is moving an add or subtract into the 'if' somewhere.
- */
-#pragma GCC diagnostic push
-#pragma GCC diagnostic warning "-Wstrict-overflow=2"
-#endif /* GCC_STRICT_OVERFLOW */
 int
 png_muldiv(png_fixed_point_p res, png_fixed_point a, png_int_32 times,
    png_int_32 divisor)
@@ -3465,9 +3388,6 @@ png_muldiv(png_fixed_point_p res, png_fixed_point a, png_int_32 times,

   return 0;
 }
-#if GCC_STRICT_OVERFLOW
-#pragma GCC diagnostic pop
-#endif /* GCC_STRICT_OVERFLOW */
 #endif /* READ_GAMMA || INCH_CONVERSIONS */

 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_INCH_CONVERSIONS_SUPPORTED)
@@ -3761,7 +3681,7 @@ png_log16bit(png_uint_32 x)
 * of getting this accuracy in practice.
 *
 * To deal with this the following exp() function works out the exponent of the
- * fractional part of the logarithm by using an accurate 32-bit value from the
+ * frational part of the logarithm by using an accurate 32-bit value from the
 * top four fractional bits then multiplying in the remaining bits.
 */
 static const png_uint_32
@@ -4358,7 +4278,7 @@ png_set_option(png_structrp png_ptr, int option, int onoff)
   defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
 /* sRGB conversion tables; these are machine generated with the code in
 * contrib/tools/makesRGB.c.  The actual sRGB transfer curve defined in the
- * specification (see the article at https://en.wikipedia.org/wiki/SRGB)
+ * specification (see the article at http://en.wikipedia.org/wiki/SRGB)
 * is used, not the gamma=1/2.2 approximation use elsewhere in libpng.
 * The sRGB to linear table is exact (to the nearest 16-bit linear fraction).
 * The inverse (linear to sRGB) table has accuracies as follows:
--- a/Show More
+++ b/Show More