[libpng16] Imported from libpng-1.6.25rc05.tar

2025-07-10 18:04:09 +02:00 · 2016-08-30 11:08:12 -05:00
77 changed files with 951 additions and 2214 deletions
--- a/47
+++ b/47
@@ -1,4 +1,4 @@
-Libpng 1.6.30beta01 - April 1, 2017
+Libpng 1.6.25rc05 - August 30, 2016

 This is not intended to be a public release.  It will be replaced
 within a few weeks by a public version or by another test version.
@@ -8,29 +8,46 @@ Files available for download:
 Source files with LF line endings (for Unix/Linux) and with a
 "configure" script

-   1.6.30beta01.tar.xz (LZMA-compressed, recommended)
-   1.6.30beta01.tar.gz
+   1.6.25rc05.tar.xz (LZMA-compressed, recommended)
+   1.6.25rc05.tar.gz

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

-   lp1630b01.7z  (LZMA-compressed, recommended)
-   lp1630b01.zip
+   lp1625r05.7z  (LZMA-compressed, recommended)
+   lp1625r05.zip

 Other information:

-   1.6.30beta01-README.txt
-   1.6.30beta01-LICENSE.txt
-   libpng-1.6.30beta01-*.asc (armored detached GPG signatures)
+   1.6.25rc05-README.txt
+   1.6.25rc05-LICENSE.txt
+   libpng-1.6.25rc05-*.asc (armored detached GPG signatures)

-Changes since the last public release (1.6.29):
+Changes since the last public release (1.6.24):

-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 1.6.25beta01 [August 12, 2016]
+  Reject oversized iCCP profile immediately.
+  Cleaned up PNG_DEBUG compile of pngtest.c.
+  Conditionally compile png_inflate().
+
+Version 1.6.25beta02 [August 18, 2016]
+  Don't install pngcp; it conflicts with pngcp in the pngtools package.
+  Minor editing of INSTALL, (whitespace, added copyright line)
+
+Version 1.6.25rc01 [August 24, 2016]
+  No changes.
+
+Version 1.6.25rc02 [August 29, 2016]
+  Added MIPS support (Mandar Sahastrabuddhe <Mandar.Sahastrabuddhe@imgtec.com>).
+  Only the UP filter is currently implemented.
+
+Version 1.6.25rc03 [August 29, 2016]
+  Rebased contrib/intel/intel_sse.patch after the MIPS implementation.
+
+Version 1.6.25rc04 [August 30, 2016]
+  Added MIPS support for SUB, AVG, and PAETH filters (Mandar Sahastrabuddhe).
+
+Version 1.6.25rc05 [August 30, 2016]

 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
--- a/128
+++ b/128
@@ -593,7 +593,7 @@ Version 1.0.5e [November 30, 1999]
    with trailing compressed parts easier in the future, and added new functions
    png_free_iCCP, png_free_pCAL, png_free_sPLT, png_free_text, png_get_iCCP,
    png_get_spalettes, png_set_iCCP, png_set_spalettes (Eric S. Raymond).
-    NOTE: Applications that write text chunks MUST define png_text->lang
+  NOTE: Applications that write text chunks MUST define png_text->lang
    before calling png_set_text(). It must be set to NULL if you want to
    write tEXt or zTXt chunks.  If you want your application to be able to
    run with older versions of libpng, use
@@ -5698,132 +5698,6 @@ Version 1.6.25rc04 [August 30, 2016]
  Added MIPS support for SUB, AVG, and PAETH filters (Mandar Sahastrabuddhe).

 Version 1.6.25rc05 [August 30, 2016]
-  Rebased contrib/intel/intel_sse.patch after the MIPS implementation update..
-
-Version 1.6.25 [September 1, 2016]
-  No changes.
-
-Version 1.6.26beta01 [September 26, 2016]
-  Fixed handling zero length IDAT in pngfix (bug report by Agostino Sarubbo,
-    bugfix by John Bowler).
-  Do not issue a png_error() on read in png_set_pCAL() because png_handle_pCAL
-    has allocated memory that libpng needs to free.
-  Conditionally compile png_set_benign_errors() in pngread.c and pngtest.c
-  Issue a png_benign_error instead of a png_error on ADLER32 mismatch
-    while decoding compressed data chunks.
-  Changed PNG_ZLIB_VERNUM to ZLIB_VERNUM in pngpriv.h, pngstruct.h, and
-    pngrutil.c.
-  If CRC handling of critical chunks has been set to PNG_CRC_QUIET_USE,
-    ignore the ADLER32 checksum in the IDAT chunk as well as the chunk CRCs.
-  Issue png_benign_error() on ADLER32 checksum mismatch instead of png_error().
-  Add tests/badcrc.png and tests/badadler.png to tests/pngtest.
-  Merged pngtest.c with libpng-1.7.0beta84/pngtest.c
-
-Version 1.6.26beta02 [October 1, 2016]
-  Updated the documentation about CRC and ADLER32 handling.
-  Quieted 117 warnings from clang-3.8 in pngtrans.c, pngread.c,
-     pngwrite.c, pngunknown.c, and pngvalid.c.
-  Quieted 58 (out of 144) -Wconversion compiler warnings by changing
-    flag definitions in pngpriv.h from 0xnnnn to 0xnnnnU and trivial changes
-    in png.c, pngread.c, and pngwutil.c.
-
-Version 1.6.26beta03 [October 2, 2016]
-  Removed contrib/libtests/*.orig and *.rej that slipped into the tarballs.
-  Quieted the 86 remaining -Wconversion compiler warnings by
-    revising the png_isaligned() macro and trivial changes in png.c,
-    pngerror.c, pngget.c, pngmem.c, pngset.c, pngrtran.c, pngrutil.c,
-    pngwtran.c, pngwrite.c, and pngwutil.c.
-
-Version 1.6.26beta04 [October 3, 2016]
-  Quieted (bogus?) clang warnings about "absolute value has no effect"
-    when PNG_USE_ABS is defined.
-  Fixed offsets in contrib/intel/intel_sse.patch
-
-Version 1.6.26beta05 [October 6, 2016]
-  Changed integer constant 4294967294 to unsigned 4294967294U in pngconf.h
-    to avoid a signed/unsigned compare in the preprocessor.
-
-Version 1.6.26beta06 [October 7, 2016]
-  Use zlib-1.2.8.1 inflateValidate() instead of inflateReset2() to
-    optionally avoid ADLER32 evaluation.
-
-Version 1.6.26rc01 [October 12, 2016]
-  No changes.
-
-Version 1.6.26 [October 20, 2016]
-  Cosmetic change, "ptr != 0" to "ptr != NULL" in png.c and pngrutil.c
-  Despammed email addresses (replaced "@" with " at ").
-
-Version 1.6.27beta01 [November 2, 2016]
-  Restrict the new ADLER32-skipping to IDAT chunks.  It broke iCCP chunk
-    handling: an erroneous iCCP chunk would throw a png_error and reject the
-    entire PNG image instead of rejecting just the iCCP chunk with a warning,
-    if built with zlib-1.2.8.1.
-
-Version 1.6.27rc01 [December 27, 2016]
-  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
-    "generates" within the C90 standard seems to imply more than simple
-    substitution of an expression itself containing a well-formed defined
-    operation.
-  Added ARM support to CMakeLists.txt (Andreas Franek).
-
-Version 1.6.27 [December 29, 2016]
-  Fixed a potential null pointer dereference in png_set_text_2() (bug report
-    and patch by Patrick Keshishian, CVE-2016-10087).
-
-Version 1.6.28rc01 [January 3, 2017]
-  Fixed arm/aarch64 detection in CMakeLists.txt (Gianfranco Costamagna).
-  Added option to Cmake build allowing a custom location of zlib to be
-    specified in a scenario where libpng is being built as a subproject
-    alongside zlib by another project (Sam Serrels).
-  Changed png_ptr->options from a png_byte to png_uint_32, to accomodate
-    up to 16 options.
-
-Version 1.6.28rc02 [January 4, 2017]
-  Added "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.
-
-Version 1.6.28rc03 [January 4, 2017]
-  Backed out the SSE optimization and last CMakeLists.txt to allow time for QA.
-
-Version 1.6.28 [January 5, 2017]
-  No changes.
-
-Version 1.6.29beta01 [January 12, 2017]
-  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).
-
-Version 1.6.29beta02 [February 22, 2017]
-  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).
-
-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.
-  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).

 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -5,7 +5,6 @@
 # Revised by Roger Lowman, 2009-2010
 # Revised by Clifford Yapp, 2011-2012
 # Revised by Roger Leigh, 2016
-# Revised by Andreas Franek, 2016

 # This code is released under the libpng license.
 # For conditions of distribution and use, see the disclaimer
@@ -36,22 +35,13 @@ enable_testing()

 set(PNGLIB_MAJOR 1)
 set(PNGLIB_MINOR 6)
-set(PNGLIB_RELEASE 30)
+set(PNGLIB_RELEASE 25)
 set(PNGLIB_NAME libpng${PNGLIB_MAJOR}${PNGLIB_MINOR})
 set(PNGLIB_VERSION ${PNGLIB_MAJOR}.${PNGLIB_MINOR}.${PNGLIB_RELEASE})

-include(GNUInstallDirs)
-
 # needed packages
-
-#Allow users to specify location of Zlib,
-# Useful if zlib is being built alongside this as a sub-project
-option(PNG_BUILD_ZLIB "Custom zlib Location, else find_package is used" OFF)
-
-IF(NOT PNG_BUILD_ZLIB)
-  find_package(ZLIB REQUIRED)
-  include_directories(${ZLIB_INCLUDE_DIR})
-ENDIF(NOT PNG_BUILD_ZLIB)
+find_package(ZLIB REQUIRED)
+include_directories(${ZLIB_INCLUDE_DIR})

 if(NOT WIN32)
  find_library(M_LIBRARY
@@ -79,68 +69,6 @@ option(PNGARG        "Disable ANSI-C prototypes" OFF)
 set(PNG_PREFIX "" CACHE STRING "Prefix to add to the API function names")
 set(DFA_XTRA "" CACHE FILEPATH "File containing extra configuration settings")

-# set definitions and sources for arm
-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;
-     off: disable the optimizations;
-     on: turn on unconditionally.")
-  set_property(CACHE PNG_ARM_NEON PROPERTY STRINGS
-     ${PNG_ARM_NEON_POSSIBLE_VALUES})
-  list(FIND PNG_ARM_NEON_POSSIBLE_VALUES ${PNG_ARM_NEON} index)
-  if(index EQUAL -1)
-    message(FATAL_ERROR
-      " PNG_ARM_NEON must be one of [${PNG_ARM_NEON_POSSIBLE_VALUES}]")
-  elseif(NOT ${PNG_ARM_NEON} STREQUAL "no")
-    set(libpng_arm_sources
-      arm/arm_init.c
-      arm/filter_neon.S
-      arm/filter_neon_intrinsics.c)
-
-    if(${PNG_ARM_NEON} STREQUAL "on")
-      add_definitions(-DPNG_ARM_NEON_OPT=2)
-    elseif(${PNG_ARM_NEON} STREQUAL "check")
-      add_definitions(-DPNG_ARM_NEON_CHECK_SUPPORTED)
-    endif()
-  else()
-    add_definitions(-DPNG_ARM_NEON_OPT=0)
-  endif()
-endif()
-
-# set definitions and sources for powerpc
-if(${CMAKE_SYSTEM_PROCESSOR} MATCHES "^powerpc*" OR
-	${CMAKE_SYSTEM_PROCESSOR} MATCHES "^ppc64*" )
-  set(PNG_POWERPC_VSX_POSSIBLE_VALUES 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 ${PNG_POWERPC_VSX} index)
-  if(index EQUAL -1)
-    message(FATAL_ERROR
-      " PNG_POWERPC_VSX must be one of [${PNG_POWERPC_VSX_POSSIBLE_VALUES}]")
-  elseif(NOT ${PNG_POWERPC_VSX} STREQUAL "no")
-    set(libpng_powerpc_sources
-      powerpc/powerpc_init.c
-      powerpc/filter_vsx_intrinsics.c)
-
-    if(${PNG_POWERPC_VSX} STREQUAL "on")
-      add_definitions(-DPNG_POWERPC_VSX_OPT=2)
-    elseif(${PNG_POWERPC_VSX} STREQUAL "check")
-      add_definitions(-DPNG_POWERPC_VSX_CHECK_SUPPORTED)
-      message(WARNING
-      "[PNG_POWERPC_VSX==check] Please check contrib/powerpc/README file for the list of supported OSes.")
-    endif()
-  else()
-    add_definitions(-DPNG_POWERPC_VSX_OPT=0)
-  endif()
-endif()
-
-
 # SET LIBNAME
 set(PNG_LIB_NAME png${PNGLIB_MAJOR}${PNGLIB_MINOR})

@@ -431,8 +359,6 @@ set(libpng_sources
  pngwrite.c
  pngwtran.c
  pngwutil.c
-  ${libpng_arm_sources}
-  ${libpng_powerpc_sources}
 )
 set(pngtest_sources
  pngtest.c
@@ -770,7 +696,7 @@ endif(NOT WIN32 OR CYGWIN OR MINGW)
 # SET UP LINKS
 if(PNG_SHARED)
  set_target_properties(png PROPERTIES
-#   VERSION 16.${PNGLIB_RELEASE}.1.6.30beta01
+#   VERSION 16.${PNGLIB_RELEASE}.1.6.25rc05
    VERSION 16.${PNGLIB_RELEASE}.0
    SOVERSION 16
    CLEAN_DIRECT_OUTPUT 1)
@@ -875,3 +801,4 @@ endif()
 # to create msvc import lib for mingw compiled shared lib
 # pexports libpng.dll > libpng.def
 # lib /def:libpng.def /machine:x86
+
--- a/9
+++ b/9
@@ -10,8 +10,8 @@ this sentence.

 This code is released under the libpng license.

-libpng versions 1.0.7, July 1, 2000 through 1.6.30beta01, April 1, 2017 are
-Copyright (c) 2000-2002, 2004, 2006-2017 Glenn Randers-Pehrson, are
+libpng versions 1.0.7, July 1, 2000 through 1.6.25rc05, August 30, 2016 are
+Copyright (c) 2000-2002, 2004, 2006-2016 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
 added to the list of Contributing Authors:
@@ -22,9 +22,6 @@ added to the list of Contributing Authors:
   Cosmin Truta
   Gilles Vollant
   James Yu
-   Mandar Sahastrabuddhe
-   Google Inc.
-   Vadim Barkov

 and with the following additions to the disclaimer:

@@ -130,4 +127,4 @@ any encryption software.  See the EAR, paragraphs 734.3(b)(3) and

 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-April 1, 2017
+August 30, 2016
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,7 +1,7 @@
 # Makefile.am, the source file for Makefile.in (and hence Makefile), is
 #
 # Copyright (c) 2004-2016 Glenn Randers-Pehrson
-# Last changed in libpng 1.6.25 [September 1, 2016]
+# Last changed in libpng 1.6.25 [(PENDING RELEASE)]
 #
 # This code is released under the libpng license.
 # For conditions of distribution and use, see the disclaimer
@@ -102,16 +102,6 @@ libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES += mips/mips_init.c\
 	mips/filter_msa_intrinsics.c
 endif

-if PNG_INTEL_SSE
-libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES += intel/intel_init.c\
-	intel/filter_sse2_intrinsics.c
-endif
-
-if PNG_POWERPC_VSX
-libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES += powerpc/powerpc_init.c\
-        powerpc/filter_vsx_intrinsics.c
-endif
-
 nodist_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES = pnglibconf.h

 libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LDFLAGS = -no-undefined -export-dynamic \
--- a/10
+++ b/10
@@ -1,4 +1,4 @@
-README for libpng version 1.6.30beta01 - April 1, 2017 (shared library 16.0)
+README for libpng version 1.6.25rc05 - August 30, 2016 (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.
@@ -90,7 +90,7 @@ 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/documents/

-This code is currently being archived at libpng.sourceforge.io in the
+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.

@@ -179,16 +179,14 @@ Files in this distribution:
      pngwtran.c    =>  Write data transformations
      pngwutil.c    =>  Write utility functions
      arm           =>  Contains optimized code for the ARM platform
-      powerpc       =>  Contains optimized code for the PowerPC platform
      contrib       =>  Contributions
       arm-neon         =>  Optimized code for ARM-NEON platform
-       powerpc-vsx      =>  Optimized code for POWERPC-VSX platform
       examples         =>  Example programs
       gregbook         =>  source code for PNG reading and writing, from
                            Greg Roelofs' "PNG: The Definitive Guide",
                            O'Reilly, 1999
+       intel            =>  Optimized code for INTEL-SSE2 platform
       libtests         =>  Test programs
-       mips-msa         =>  Optimized code for MIPS-MSA platform
       pngminim         =>  Minimal decoder, encoder, and progressive decoder
                            programs demonstrating use of pngusr.dfa
       pngminus         =>  Simple pnm2png and png2pnm programs
@@ -196,8 +194,6 @@ Files in this distribution:
       testpngs
       tools            =>  Various tools
       visupng          =>  Contains a MSVC workspace for VisualPng
-      intel             =>  Optimized code for INTEL-SSE2 platform
-      mips              =>  Optimized code for MIPS platform
      projects      =>  Contains project files and workspaces for
                        building a DLL
       owatcom          =>  Contains a WATCOM project for building libpng
--- a/4
+++ b/4
@@ -7,7 +7,7 @@ Fix problem with C++ and EXTERN "C".
 cHRM transformation.
 Remove setjmp/longjmp usage in favor of returning error codes. As a start on
  this, minimize the use of png_error(), replacing them with
-  png_warning(); return(0); or similar.
+  png_warning(); return(0; or similar.
 Palette creation.
 Add "grayscale->palette" transformation and "palette->grayscale" detection.
 Improved dithering.
@@ -24,7 +24,7 @@ Use greater precision when changing to linear gamma for compositing against
  background and doing rgb-to-gray transformation.
 Investigate pre-incremented loop counters and other loop constructions.
 Add interpolated method of handling interlacing.
+Switch to the simpler zlib (zlib/libpng) license if legally possible.
 Extend pngvalid.c to validate more of the libpng transformations.
-Refactor preprocessor conditionals to compile entire statements

 */
--- a/configure.ac
+++ b/configure.ac
@@ -1,7 +1,7 @@
 # configure.ac

 # Copyright (c) 2004-2016 Glenn Randers-Pehrson
-# Last changed in libpng 1.6.25 [September 1, 2016]
+# Last changed in libpng 1.6.25 [(PENDING RELEASE)]

 # This code is released under the libpng license.
 # For conditions of distribution and use, see the disclaimer
@@ -25,7 +25,7 @@ AC_PREREQ([2.68])

 dnl Version number stuff here:

-AC_INIT([libpng],[1.6.30beta01],[png-mng-implement@lists.sourceforge.net])
+AC_INIT([libpng],[1.6.25rc05],[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=1.6.30beta01
+PNGLIB_VERSION=1.6.25rc05
 PNGLIB_MAJOR=1
 PNGLIB_MINOR=6
-PNGLIB_RELEASE=28
+PNGLIB_RELEASE=25

 dnl End of version number stuff

@@ -391,89 +391,6 @@ AM_CONDITIONAL([PNG_MIPS_MSA],
      mipsel*|mips64el*) :;;
    esac])

-# INTEL
-# =====
-#
-# INTEL SSE (SIMD) support.
-
-AC_ARG_ENABLE([intel-sse],
-   AS_HELP_STRING([[[--enable-intel-sse]]],
-      [Enable Intel SSE optimizations: =no/off, yes/on:]
-      [no/off: disable the optimizations;]
-      [yes/on: enable the optimizations.]
-      [If not specified: determined by the compiler.]),
-   [case "$enableval" in
-      no|off)
-         # disable the default enabling:
-         AC_DEFINE([PNG_INTEL_SSE_OPT], [0],
-                   [Disable Intel SSE optimizations])
-         # Prevent inclusion of the assembler files below:
-         enable_intel_sse=no;;
-      yes|on)
-         AC_DEFINE([PNG_INTEL_SSE_OPT], [1],
-                   [Enable Intel SSE optimizations]);;
-      *)
-         AC_MSG_ERROR([--enable-intel-sse=${enable_intel_sse}: invalid value])
-   esac])
-
-# Add Intel specific files to all builds where the host_cpu is Intel ('x86*')
-# or where Intel optimizations were explicitly requested (this allows a
-# fallback if a future host CPU does not match 'x86*')
-AM_CONDITIONAL([PNG_INTEL_SSE],
-   [test "$enable_intel_sse" != 'no' &&
-    case "$host_cpu" in
-      i?86|x86_64) :;;
-      *)    test "$enable_intel_sse" != '';;
-    esac])
-
-# PowerPC
-# ===
-#
-# PowerPC VSX (SIMD) support.
-
-AC_ARG_ENABLE([powerpc-vsx],
-AS_HELP_STRING([[[--enable-powerpc-vsx]]],
-      [Enable POWERPC VSX optimizations: =no/off, check, api, yes/on:]
-      [no/off: disable the optimizations; check: use internal checking code]
-      [api: disable by default, enable by a call to png_set_option]
-      [yes/on: turn on unconditionally.]
-      [If not specified: determined by the compiler.]),
-   [case "$enableval" in
-      no|off)
-         # disable the default enabling on __ppc64__ systems:
-         AC_DEFINE([PNG_POWERPC_VSX_OPT], [0],
-                   [Disable POWERPC VSX optimizations])
-         # Prevent inclusion of the platform specific files below:
-         enable_powerpc_vsx=no;;
-      check)
-         AC_DEFINE([PNG_POWERPC_VSX_CHECK_SUPPORTED], [],
-                   [Check for POWERPC VSX support at run-time])
-         AC_MSG_WARN([--enable-powerpc-vsx Please check contrib/powerpc/README file]
-            [for the list of supported OSes.]);;
-      api)
-         AC_DEFINE([PNG_POWERPC_VSX_API_SUPPORTED], [],
-                   [Turn on POWERPC VSX optimizations at run-time]);;
-      yes|on)
-         AC_DEFINE([PNG_POWERPC_VSX_OPT], [2],
-                   [Enable POWERPC VSX optimizations])
-         AC_MSG_WARN([--enable-powerpc-vsx: please specify 'check' or 'api', if]
-            [you want the optimizations unconditionally pass '-maltivec -mvsx']
-            [or '-mcpu=power8'to the compiler.]);;
-      *)
-         AC_MSG_ERROR([--enable-powerpc-vsx=${enable_powerpc_vsx}: invalid value])
-   esac])
-
-# Add PowerPC specific files to all builds where the host_cpu is powerpc('powerpc*') or
-# where POWERPC optimizations were explicitly requested (this allows a fallback if a
-# future host CPU does not match 'powerpc*')
-
-AM_CONDITIONAL([PNG_POWERPC_VSX],
-   [test "$enable_powerpc_vsx" != 'no' &&
-    case "$host_cpu" in
-      powerpc*|ppc64*) :;;
-    esac])
-
-
 AC_MSG_NOTICE([[Extra options for compiler: $PNG_COPTS]])

 # Config files, substituting as above
--- 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/examples/README.txt
+++ b/contrib/examples/README.txt
@@ -21,4 +21,4 @@ ORIGINAL AUTHORS
    of the people below claim any rights with regard to the contents of this
    directory.

-    John Bowler <jbowler at acm.org>
+    John Bowler <jbowler@acm.org>
--- a/contrib/examples/pngtopng.c
+++ b/contrib/examples/pngtopng.c
@@ -1,12 +1,10 @@
 /*- pngtopng
 *
- * COPYRIGHT: Written by John Cunningham Bowler, 2011, 2017.
+ * COPYRIGHT: Written by John Cunningham Bowler, 2011.
 * 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.
 *
- * Last changed in libpng 1.6.29 [March 16, 2017]
- *
 * Read a PNG and write it out in a fixed format, using the 'simplified API'
 * that was introduced in libpng-1.6.0.
 *
@@ -61,27 +59,26 @@ int main(int argc, const char **argv)
               else
                  fprintf(stderr, "pngtopng: write %s: %s\n", argv[2],
                      image.message);
+
+               free(buffer);
            }

            else
+            {
               fprintf(stderr, "pngtopng: read %s: %s\n", argv[1],
                   image.message);

-            free(buffer);
+               /* This is the only place where a 'free' is required; libpng does
+                * the cleanup on error and success, but in this case we couldn't
+                * complete the read because of running out of memory.
+                */
+               png_image_free(&image);
+            }
         }

         else
-         {
            fprintf(stderr, "pngtopng: out of memory: %lu bytes\n",
               (unsigned long)PNG_IMAGE_SIZE(image));
-
-            /* This is the only place where a 'free' is required; libpng does
-             * the cleanup on error and success, but in this case we couldn't
-             * complete the read because of running out of memory and so libpng
-             * has not got to the point where it can do cleanup.
-             */
-            png_image_free(&image);
-         }
      }

      else
--- a/contrib/gregbook/README
+++ b/contrib/gregbook/README
@@ -15,7 +15,7 @@ of PBMPLUS/NetPBM) and converts them to PNG.

 The source code for all three demo programs currently compiles under
 Unix, OpenVMS, and 32-bit Windows.  (Special thanks to Martin Zinser,
-zinser at decus.de, for making the necessary changes for OpenVMS and for
+zinser@decus.de, for making the necessary changes for OpenVMS and for
 providing an appropriate build script.)  Build instructions can be found
 below.

@@ -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


--- a/contrib/gregbook/rpng-win.c
+++ b/contrib/gregbook/rpng-win.c
@@ -182,7 +182,7 @@ int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, PSTR cmd, int showmode)
 #ifndef __CYGWIN__
    /* First reenable console output, which normally goes to the bit bucket
     * for windowed apps.  Closing the console window will terminate the
-     * app.  Thanks to David.Geldreich at realviz.com for supplying the magical
+     * app.  Thanks to David.Geldreich@realviz.com for supplying the magical
     * incantation. */

    AllocConsole();
--- a/contrib/gregbook/rpng2-win.c
+++ b/contrib/gregbook/rpng2-win.c
@@ -301,7 +301,7 @@ int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, PSTR cmd, int showmode)
 #ifndef __CYGWIN__
    /* Next reenable console output, which normally goes to the bit bucket
     * for windowed apps.  Closing the console window will terminate the
-     * app.  Thanks to David.Geldreich at realviz.com for supplying the magical
+     * app.  Thanks to David.Geldreich@realviz.com for supplying the magical
     * incantation. */

    AllocConsole();
--- a/contrib/intel/INSTALL
+++ b/contrib/intel/INSTALL
@@ -0,0 +1,158 @@
+Enabling SSE support
+
+Copyright (c) 2016 Google, Inc.
+Written by Mike Klein, Matt Sarett
+
+This INSTALL file written by Glenn Randers-Pehrson, 2016.
+
+If you have moved intel_init.c and filter_sse2_intrinsics.c to a different
+directory, be sure to update the '#include "../../pngpriv.h"' line in both
+files if necessary to point to the correct relative location of pngpriv.h
+with respect to the new location of those files.
+
+To enable SSE support in libpng, follow the instructions in I, II, or III,
+below:
+
+I. Using patched "configure" scripts:
+
+First, apply intel_sse.patch in your build directory.
+
+   patch -i contrib/intel/intel_sse.patch -p1
+
+Then, if you are not building in a new GIT clone, e.g., in a tar
+distribution, remove any existing pre-built configure scripts:
+
+   ./configure --enable-maintainer-mode
+   make maintainer-clean
+   ./autogen.sh --maintainer --clean
+
+Finally, configure libpng with -DPNG_INTEL_SSE in CPPFLAGS:
+
+   ./autogen.sh --maintainer
+   CPPFLAGS="-DPNG_INTEL_SSE" ./configure [options]
+   make CPPFLAGS="-DPNG_INTEL_SSE" [options]
+   make
+
+II. Using a custom makefile:
+
+If you are using a custom makefile makefile, you will have to update it
+manually to include contrib/intel/*.o in the dependencies, and to define
+PNG_INTEL_SSE.
+
+III. Using manually updated "configure" scripts:
+
+If you prefer, manually edit pngpriv.h, configure.ac, and Makefile.am,
+following the instructions below, then follow the instructions in
+section II of INSTALL in the main libpng directory, then configure libpng
+with -DPNG_INTEL_SSE in CPPFLAGS.
+
+1. Add the following code to configure.ac under HOST SPECIFIC OPTIONS
+directly beneath the section for ARM:
+
+-----------------cut----------------
+# INTEL
+# =====
+#
+# INTEL SSE (SIMD) support.
+
+AC_ARG_ENABLE([intel-sse],
+   AS_HELP_STRING([[[--enable-intel-sse]]],
+      [Enable Intel SSE optimizations: =no/off, yes/on:]
+      [no/off: disable the optimizations;]
+      [yes/on: enable the optimizations.]
+      [If not specified: determined by the compiler.]),
+   [case "$enableval" in
+      no|off)
+         # disable the default enabling:
+         AC_DEFINE([PNG_INTEL_SSE_OPT], [0],
+                   [Disable Intel SSE optimizations])
+         # Prevent inclusion of the assembler files below:
+         enable_intel_sse=no;;
+      yes|on)
+         AC_DEFINE([PNG_INTEL_SSE_OPT], [1],
+                   [Enable Intel SSE optimizations]);;
+      *)
+         AC_MSG_ERROR([--enable-intel-sse=${enable_intel_sse}: invalid value])
+   esac])
+
+# Add Intel specific files to all builds where the host_cpu is Intel ('x86*')
+# or where Intel optimizations were explicitly requested (this allows a
+# fallback if a future host CPU does not match 'x86*')
+AM_CONDITIONAL([PNG_INTEL_SSE],
+   [test "$enable_intel_sse" != 'no' &&
+    case "$host_cpu" in
+      i?86|x86_64) :;;
+      *)    test "$enable_intel_sse" != '';;
+    esac])
+-----------------cut----------------
+
+2. Add the following code to Makefile.am under HOST SPECIFIC OPTIONS
+directly beneath the "if PNG_ARM_NEON ... endif" statement:
+
+-----------------cut----------------
+if PNG_INTEL_SSE
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES += contrib/intel/intel_init.c\
+    contrib/intel/filter_sse2_intrinsics.c
+endif
+-----------------cut----------------
+
+3. Add the following lines to pngpriv.h, following the PNG_ARM_NEON_OPT
+code:
+
+-----------------cut----------------
+#ifndef PNG_INTEL_SSE_OPT
+#   ifdef PNG_INTEL_SSE
+      /* Only check for SSE if the build configuration has been modified to
+       * enable SSE optimizations.  This means that these optimizations will
+       * be off by default.  See contrib/intel for more details.
+       */
+#     if defined(__SSE4_1__) || defined(__AVX__) || defined(__SSSE3__) || \
+       defined(__SSE2__) || defined(_M_X64) || defined(_M_AMD64) || \
+       (defined(_M_IX86_FP) && _M_IX86_FP >= 2)
+#         define PNG_INTEL_SSE_OPT 1
+#      endif
+#   endif
+#endif
+
+#if PNG_INTEL_SSE_OPT > 0
+#   ifndef PNG_INTEL_SSE_IMPLEMENTATION
+#      if defined(__SSE4_1__) || defined(__AVX__)
+          /* We are not actually using AVX, but checking for AVX is the best
+             way we can detect SSE4.1 and SSSE3 on MSVC.
+          */
+#         define PNG_INTEL_SSE_IMPLEMENTATION 3
+#      elif defined(__SSSE3__)
+#         define PNG_INTEL_SSE_IMPLEMENTATION 2
+#      elif defined(__SSE2__) || defined(_M_X64) || defined(_M_AMD64) || \
+       (defined(_M_IX86_FP) && _M_IX86_FP >= 2)
+#         define PNG_INTEL_SSE_IMPLEMENTATION 1
+#      else
+#         define PNG_INTEL_SSE_IMPLEMENTATION 0
+#      endif
+#   endif
+
+#   if PNG_INTEL_SSE_IMPLEMENTATION > 0
+#      define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_sse2
+#   endif
+#endif
+
+-----------------cut----------------
+
+4. Add the following lines to pngpriv.h, following the prototype for
+png_read_filter_row_paeth4_neon:
+
+-----------------cut----------------
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_sse2,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_sse2,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_sse2,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_sse2,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_sse2,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_sse2,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+
+-----------------cut----------------
--- a/contrib/intel/filter_sse2_intrinsics.c
+++ b/contrib/intel/filter_sse2_intrinsics.c
@@ -1,18 +1,19 @@

 /* filter_sse2_intrinsics.c - SSE2 optimized filter functions
 *
- * Copyright (c) 2016-2017 Glenn Randers-Pehrson
+ * Copyright (c) 2016 Google, Inc.
 * Written by Mike Klein and Matt Sarett
- * Derived from arm/filter_neon_intrinsics.c
+ * Derived from arm/filter_neon_intrinsics.c, which was
+ * Copyright (c) 2014,2016 Glenn Randers-Pehrson
 *
- * Last changed in libpng 1.6.29 [(PENDING RELEASE)]
+ * 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
 * and license in png.h
 */

-#include "../pngpriv.h"
+#include "../../pngpriv.h"

 #ifdef PNG_READ_SUPPORTED

--- a/contrib/intel/intel_init.c
+++ b/contrib/intel/intel_init.c
@@ -1,18 +1,19 @@

 /* intel_init.c - SSE2 optimized filter functions
 *
- * Copyright (c) 2016-2017 Glenn Randers-Pehrson
- * Written by Mike Klein and Matt Sarett, Google, Inc.
- * Derived from arm/arm_init.c
+ * Copyright (c) 2016 Google, Inc.
+ * Written by Mike Klein and Matt Sarett
+ * Derived from arm/arm_init.c, which was
+ * Copyright (c) 2014,2016 Glenn Randers-Pehrson
 *
- * Last changed in libpng 1.6.29 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.22 [May 26, 2016]
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
 * and license in png.h
 */

-#include "../pngpriv.h"
+#include "../../pngpriv.h"

 #ifdef PNG_READ_SUPPORTED
 #if PNG_INTEL_SSE_IMPLEMENTATION > 0
--- a/contrib/intel/intel_sse.patch
+++ b/contrib/intel/intel_sse.patch
@@ -0,0 +1,190 @@
+diff --git a/configure.ac b/configure.ac
+--- a/configure.ac	2016-08-29 11:46:27.000000000 -0400
+++ b/configure.ac	2016-08-29 16:57:03.866355018 -0400
+@@ -386,16 +386,51 @@ AC_ARG_ENABLE([mips-msa],
+ # future host CPU does not match 'mips*')
+ 
+ AM_CONDITIONAL([PNG_MIPS_MSA],
+    [test "$enable_mips_msa" != 'no' &&
+     case "$host_cpu" in
+       mipsel*|mips64el*) :;;
+     esac])
+ 
+# INTEL
+# =====
+#
+# INTEL SSE (SIMD) support.
+
+AC_ARG_ENABLE([intel-sse],
+   AS_HELP_STRING([[[--enable-intel-sse]]],
+      [Enable Intel SSE optimizations: =no/off, yes/on:]
+      [no/off: disable the optimizations;]
+      [yes/on: enable the optimizations.]
+      [If not specified: determined by the compiler.]),
+   [case "$enableval" in
+      no|off)
+         # disable the default enabling:
+         AC_DEFINE([PNG_INTEL_SSE_OPT], [0],
+                   [Disable Intel SSE optimizations])
+         # Prevent inclusion of the assembler files below:
+         enable_intel_sse=no;;
+      yes|on)
+         AC_DEFINE([PNG_INTEL_SSE_OPT], [1],
+                   [Enable Intel SSE optimizations]);;
+      *)
+         AC_MSG_ERROR([--enable-intel-sse=${enable_intel_sse}: invalid value])
+   esac])
+
+# Add Intel specific files to all builds where the host_cpu is Intel ('x86*')
+# or where Intel optimizations were explicitly requested (this allows a
+# fallback if a future host CPU does not match 'x86*')
+AM_CONDITIONAL([PNG_INTEL_SSE],
+   [test "$enable_intel_sse" != 'no' &&
+    case "$host_cpu" in
+      i?86|x86_64) :;;
+      *)    test "$enable_intel_sse" != '';;
+    esac])
+
+ AC_MSG_NOTICE([[Extra options for compiler: $PNG_COPTS]])
+ 
+ # Config files, substituting as above
+ AC_CONFIG_FILES([Makefile libpng.pc:libpng.pc.in])
+ AC_CONFIG_FILES([libpng-config:libpng-config.in],
+    [chmod +x libpng-config])
+ 
+ AC_OUTPUT
+diff --git a/Makefile.am b/Makefile.am
+--- a/Makefile.am	2016-08-29 11:46:27.000000000 -0400
+++ b/Makefile.am	2016-08-29 16:57:45.955528215 -0400
+@@ -97,16 +97,21 @@ libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SO
+ 	arm/filter_neon.S arm/filter_neon_intrinsics.c
+ endif
+ 
+ if PNG_MIPS_MSA
+ libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES += mips/mips_init.c\
+ 	mips/filter_msa_intrinsics.c
+ endif
+ 
+if PNG_INTEL_SSE
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES += contrib/intel/intel_init.c\
+    contrib/intel/filter_sse2_intrinsics.c
+endif
+
+ nodist_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES = pnglibconf.h
+ 
+ libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LDFLAGS = -no-undefined -export-dynamic \
+ 	-version-number @PNGLIB_MAJOR@@PNGLIB_MINOR@:@PNGLIB_RELEASE@:0
+ 
+ if HAVE_LD_VERSION_SCRIPT
+ #   Versioned symbols and restricted exports
+ if HAVE_SOLARIS_LD
+diff --git a/pngpriv.h b/pngpriv.h
+--- debug16/pngpriv.h	2016-08-30 10:46:36.000000000 -0400
+++ libpng16/pngpriv.h	2016-08-30 11:57:25.672280202 -0400
+@@ -185,16 +185,52 @@
+ #ifndef PNG_MIPS_MSA_OPT
+ #  if defined(__mips_msa) && (__mips_isa_rev >= 5) && defined(PNG_ALIGNED_MEMORY_SUPPORTED)
+ #     define PNG_MIPS_MSA_OPT 2
+ #  else
+ #     define PNG_MIPS_MSA_OPT 0
+ #  endif
+ #endif
+ 
+#ifndef PNG_INTEL_SSE_OPT
+#   ifdef PNG_INTEL_SSE
+      /* Only check for SSE if the build configuration has been modified to
+       * enable SSE optimizations.  This means that these optimizations will
+       * be off by default.  See contrib/intel for more details.
+       */
+#     if defined(__SSE4_1__) || defined(__AVX__) || defined(__SSSE3__) || \
+       defined(__SSE2__) || defined(_M_X64) || defined(_M_AMD64) || \
+       (defined(_M_IX86_FP) && _M_IX86_FP >= 2)
+#         define PNG_INTEL_SSE_OPT 1
+#      endif
+#   endif
+#endif
+
+#if PNG_INTEL_SSE_OPT > 0
+#   ifndef PNG_INTEL_SSE_IMPLEMENTATION
+#      if defined(__SSE4_1__) || defined(__AVX__)
+          /* We are not actually using AVX, but checking for AVX is the best
+             way we can detect SSE4.1 and SSSE3 on MSVC.
+          */
+#         define PNG_INTEL_SSE_IMPLEMENTATION 3
+#      elif defined(__SSSE3__)
+#         define PNG_INTEL_SSE_IMPLEMENTATION 2
+#      elif defined(__SSE2__) || defined(_M_X64) || defined(_M_AMD64) || \
+       (defined(_M_IX86_FP) && _M_IX86_FP >= 2)
+#         define PNG_INTEL_SSE_IMPLEMENTATION 1
+#      else
+#         define PNG_INTEL_SSE_IMPLEMENTATION 0
+#      endif
+#   endif
+
+#   if PNG_INTEL_SSE_IMPLEMENTATION > 0
+#      define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_sse2
+#   endif
+#endif
+
+ #if PNG_MIPS_MSA_OPT > 0
+ #  define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_msa
+ #  ifndef PNG_MIPS_MSA_IMPLEMENTATION
+ #     if defined(__mips_msa)
+ #        if defined(__clang__)
+ #        elif defined(__GNUC__)
+ #           if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 7)
+ #              define PNG_MIPS_MSA_IMPLEMENTATION 2
+@@ -1232,16 +1268,31 @@ PNG_INTERNAL_FUNCTION(void,png_read_filt
+ PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_msa,(png_row_infop
+     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+ PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_msa,(png_row_infop
+     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+ PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_msa,(png_row_infop
+     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+ #endif
+ 
+#if PNG_INTEL_SSE_IMPLEMENTATION > 0
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_sse2,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_sse2,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_sse2,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_sse2,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_sse2,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_sse2,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+#endif
+
+ /* Choose the best filter to use and filter the row data */
+ PNG_INTERNAL_FUNCTION(void,png_write_find_filter,(png_structrp png_ptr,
+     png_row_infop row_info),PNG_EMPTY);
+ 
+ #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+ PNG_INTERNAL_FUNCTION(void,png_read_IDAT_data,(png_structrp png_ptr,
+    png_bytep output, png_alloc_size_t avail_out),PNG_EMPTY);
+    /* Read 'avail_out' bytes of data from the IDAT stream.  If the output buffer
+@@ -1967,16 +2018,21 @@ PNG_INTERNAL_FUNCTION(void, PNG_FILTER_O
+ PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_neon,
+    (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
+ #endif
+ 
+ #if PNG_MIPS_MSA_OPT > 0
+ PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_msa,
+    (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
+ #endif
+
+#  if PNG_INTEL_SSE_IMPLEMENTATION > 0
+PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_sse2,
+   (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
+#  endif
+ #endif
+ 
+ PNG_INTERNAL_FUNCTION(png_uint_32, png_check_keyword, (png_structrp png_ptr,
+    png_const_charp key, png_bytep new_key), PNG_EMPTY);
+ 
+ /* Maintainer: Put new private prototypes here ^ */
+ 
+ #include "pngdebug.h"
--- a/contrib/libtests/pngunknown.c
+++ b/contrib/libtests/pngunknown.c
@@ -1,7 +1,7 @@

 /* pngunknown.c - test the read side unknown chunk handling
 *
- * Last changed in libpng 1.6.26 [October 20, 2016]
+ * Last changed in libpng 1.6.22 [May 26, 2016]
 * Copyright (c) 2015,2016 Glenn Randers-Pehrson
 * Written by John Cunningham Bowler
 *
@@ -478,7 +478,7 @@ get_valid(display *d, png_infop info_ptr)
      png_textp text;
      png_uint_32 ntext = png_get_text(d->png_ptr, info_ptr, &text, NULL);

-      while (ntext > 0) switch (text[--ntext].compression)
+      while (ntext-- > 0) switch (text[ntext].compression)
      {
         case -1:
            flags |= PNG_INFO_tEXt;
--- a/contrib/libtests/pngvalid.c
+++ b/contrib/libtests/pngvalid.c
@@ -1,8 +1,9 @@

 /* pngvalid.c - validate libpng by constructing then reading png files.
 *
- * Last changed in libpng 1.6.29 [March 16, 2017]
- * Copyright (c) 2014-2017 John Cunningham Bowler
+ * Last changed in libpng 1.6.24 [August 4, 2016]
+ * Copyright (c) 2014-2016 Glenn Randers-Pehrson
+ * Written by John Cunningham Bowler
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
@@ -1241,7 +1242,7 @@ store_image_check(const png_store* ps, png_const_structp pp, int iImage)

      image += 2; /* skip image first row markers */

-      for (; rows > 0; --rows)
+      while (rows-- > 0)
      {
         if (image[-2] != 190 || image[-1] != 239)
            png_error(pp, "row start overwritten");
@@ -4010,11 +4011,8 @@ check_interlace_type(int const interlace_type)
 #  define do_own_interlace 1
 #endif /* WRITE_INTERLACING tests */

-#if PNG_LIBPNG_VER >= 10700 || defined PNG_WRITE_INTERLACING_SUPPORTED
-#   define CAN_WRITE_INTERLACE 1
-#else
-#   define CAN_WRITE_INTERLACE 0
-#endif
+#define CAN_WRITE_INTERLACE\
+   PNG_LIBPNG_VER >= 10700 || defined PNG_WRITE_INTERLACING_SUPPORTED

 /* Do the same thing for read interlacing; this controls whether read tests do
 * their own de-interlace or use libpng.
@@ -7742,11 +7740,13 @@ image_transform_png_set_rgb_to_gray_ini(const image_transform *this,
          * NOTE: this number only affects the internal limit check in pngvalid,
          * it has no effect on the limits applied to the libpng values.
          */
-#if DIGITIZE
-          that->pm->limit += pow( 2.0/255, data.gamma);
-#else
-          that->pm->limit += pow( 1.0/255, data.gamma);
-#endif
+         that->pm->limit += pow(
+#        if DIGITIZE
+            2.0
+#        else
+            1.0
+#        endif
+            /255, data.gamma);
      }
   }

@@ -11427,36 +11427,23 @@ perform_interlace_macro_validation(void)
       */
      for (v=0;;)
      {
-         /* The first two tests overflow if the pass row or column is outside
-          * the possible range for a 32-bit result.  In fact the values should
-          * never be outside the range for a 31-bit result, but checking for 32
-          * bits here ensures that if an app uses a bogus pass row or column
-          * (just so long as it fits in a 32 bit integer) it won't get a
-          * possibly dangerous overflow.
-          */
         /* First the base 0 stuff: */
-         if (v < png_pass_rows(0xFFFFFFFFU, pass))
+         m = PNG_ROW_FROM_PASS_ROW(v, pass);
+         f = png_row_from_pass_row(v, pass);
+         if (m != f)
         {
-            m = PNG_ROW_FROM_PASS_ROW(v, pass);
-            f = png_row_from_pass_row(v, pass);
-            if (m != f)
-            {
-               fprintf(stderr, "PNG_ROW_FROM_PASS_ROW(%u, %d) = %u != %x\n",
-                  v, pass, m, f);
-               exit(99);
-            }
+            fprintf(stderr, "PNG_ROW_FROM_PASS_ROW(%u, %d) = %u != %x\n",
+               v, pass, m, f);
+            exit(99);
         }

-         if (v < png_pass_cols(0xFFFFFFFFU, pass))
+         m = PNG_COL_FROM_PASS_COL(v, pass);
+         f = png_col_from_pass_col(v, pass);
+         if (m != f)
         {
-            m = PNG_COL_FROM_PASS_COL(v, pass);
-            f = png_col_from_pass_col(v, pass);
-            if (m != f)
-            {
-               fprintf(stderr, "PNG_COL_FROM_PASS_COL(%u, %d) = %u != %x\n",
-                  v, pass, m, f);
-               exit(99);
-            }
+            fprintf(stderr, "PNG_COL_FROM_PASS_COL(%u, %d) = %u != %x\n",
+               v, pass, m, f);
+            exit(99);
         }

         m = PNG_ROW_IN_INTERLACE_PASS(v, pass);
--- a/contrib/pngminus/README
+++ b/contrib/pngminus/README
@@ -146,7 +146,7 @@ The Turbo bug
 The end
 -------
 Willem van Schaik
-mailto:willem at schaik.com
+mailto:willem@schaik.com
 http://www.schaik.com/png/
 -------
 Oct 1999
--- a/contrib/pngminus/png2pnm.c
+++ b/contrib/pngminus/png2pnm.c
@@ -1,6 +1,6 @@
 /*
 *  png2pnm.c --- conversion from PNG-file to PGM/PPM-file
- *  copyright (C) 1999 by Willem van Schaik <willem at schaik.com>
+ *  copyright (C) 1999 by Willem van Schaik <willem@schaik.com>
 *
 *  version 1.0 - 1999.10.15 - First version.
 *
--- a/contrib/pngminus/pnm2png.c
+++ b/contrib/pngminus/pnm2png.c
@@ -1,6 +1,6 @@
 /*
 *  pnm2png.c --- conversion from PBM/PGM/PPM-file to PNG-file
- *  copyright (C) 1999 by Willem van Schaik <willem at schaik.com>
+ *  copyright (C) 1999 by Willem van Schaik <willem@schaik.com>
 *
 *  version 1.0 - 1999.10.15 - First version.
 *  version 1.1 - 2015.07.29 - Fixed leaks (Glenn Randers-Pehrson)
--- a/contrib/pngsuite/README
+++ b/contrib/pngsuite/README
@@ -101,5 +101,5 @@ Testing basn6a16.png: PASS (1072 zero samples)
 libpng passes test

 Willem van Schaik
-<willem at schaik.com>
+<willem@schaik.com>
 October 1999
--- a/contrib/powerpc-vsx/README
+++ b/contrib/powerpc-vsx/README
@@ -1,81 +0,0 @@
-OPERATING SYSTEM SPECIFIC POWERPC DETECTION
--------------------------------------------
-
-Detection of the ability to execute POWERPC on processor requires
-operating system support.  (The information is not available in user mode.)
-
-Currently only this feature is supported only for linux platform.
-
-HOW TO USE THIS
---------------
-
-This directory contains C code fragments that can be included in powerpc/powerpc_init.c
-by setting the macro PNG_POWERPC_VSX_FILE to the file name in "" or <> at build
-time.  This setting is not recorded in pnglibconf.h and can be changed simply by
-rebuilding arm/arm_init.o with the required macro definition.
-
-For any of this code to be used the POWERPC code must be enabled and run time
-checks must be supported.  I.e.:
-
-#if PNG_POWERPC_VSX_OPT > 0
-#ifdef PNG_POWERPC_VSX_CHECK_SUPPORTED
-
-This is done in a 'configure' build by passing configure the argument:
-
-   --enable-powerpc-vsx=check
-
-FILE FORMAT
-----------
-
-Each file documents its testing status as of the last time it was tested (which
-may have been a long time ago):
-
-STATUS: one of:
-   SUPPORTED: This indicates that the file is included in the regularly
-         performed test builds and bugs are fixed when discovered.
-   COMPILED: This indicates that the code did compile at least once.  See the
-         more detailed description for the extent to which the result was
-         successful.
-   TESTED: This means the code was fully compiled into the libpng test programs
-         and these were run at least once.
-
-BUG REPORTS: an email address to which to send reports of problems
-
-The file is a fragment of C code. It should not define any 'extern' symbols;
-everything should be static.  It must define the function:
-
-static int png_have_vsx(png_structp png_ptr);
-
-That function must return 1 if ARM NEON instructions are supported, 0 if not.
-It must not execute png_error unless it detects a bug.  A png_error will prevent
-the reading of the PNG and in the future, writing too.
-
-BUG REPORTS
-----------
-
-If you mail a bug report for any file that is not SUPPORTED there may only be
-limited response.  Consider fixing it and sending a patch to fix the problem -
-this is more likely to result in action.
-
-CONTRIBUTIONS
-------------
-
-You may send contributions of new implementations to
-png-mng-implement@sourceforge.net.  Please write code in strict C90 C where
-possible.  Obviously OS dependencies are to be expected.  If you submit code you
-must have the authors permission and it must have a license that is acceptable
-to the current maintainer; in particular that license must permit modification
-and redistribution.
-
-Please try to make the contribution a single file and give the file a clear and
-unambiguous name that identifies the target OS.  If multiple files really are
-required put them all in a sub-directory.
-
-You must also be prepared to handle bug reports from users of the code, either
-by joining the png-mng-implement mailing list or by providing an email for the
-"BUG REPORTS" entry or both.  Please make sure that the header of the file
-contains the STATUS and BUG REPORTS fields as above.
-
-Please list the OS requirements as precisely as possible.  Ideally you should
-also list the environment in which the code has been tested and certainly list
-any environments where you suspect it might not work.
--- a/contrib/powerpc-vsx/linux.c
+++ b/contrib/powerpc-vsx/linux.c
@@ -1,57 +0,0 @@
-/* contrib/powerpc-vsx/linux.c
- *
- * Copyright (c) 2017 Glenn Randers-Pehrson
- * Written by Vadim Barkov, 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
- * and license in png.h
- *
- * STATUS: TESTED
- * BUG REPORTS: png-mng-implement@sourceforge.net
- *
- * png_have_vsx implemented for Linux by reading the widely available
- * pseudo-file /proc/cpuinfo. 
- *
- * This code is strict ANSI-C and is probably moderately portable; it does
- * however use <stdio.h> and it assumes that /proc/cpuinfo is never localized.
- */
-
-#include <stdio.h>
-#include <string.h>
-#include <stdlib.h>
-#include "png.h"
-
-#ifndef MAXLINE
-#  define MAXLINE 1024
-#endif
-
-static int
-png_have_vsx(png_structp png_ptr)
-{
-   FILE *f;
-
-   const char *string = "altivec supported";
-   char input[MAXLINE];
-   char *token = NULL;
-
-   PNG_UNUSED(png_ptr)
-
-   f = fopen("/proc/cpuinfo", "r");
-   if (f != NULL)
-   {
-      memset(input,0,MAXLINE);
-      while(fgets(input,MAXLINE,f) != NULL)
-      {
-         token = strstr(input,string);
-         if(token != NULL)
-            return 1;
-      }
-   }
-#ifdef PNG_WARNINGS_SUPPORTED
-   else
-      png_warning(png_ptr, "/proc/cpuinfo open failed");
-#endif
-   return 0;
-}
--- a/contrib/powerpc-vsx/linux_aux.c
+++ b/contrib/powerpc-vsx/linux_aux.c
@@ -1,36 +0,0 @@
-/* contrib/powerpc-vsx/linux_aux.c
- *
- * Copyright (c) 2017 Glenn Randers-Pehrson
- * Written by Vadim Barkov, 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
- * and license in png.h
- *
- * STATUS: TESTED
- * BUG REPORTS: png-mng-implement@sourceforge.net
- *
- * png_have_vsx implemented for Linux by using the auxiliary vector mechanism.
- *
- * This code is strict ANSI-C and is probably moderately portable; it does
- * however use <stdio.h> and it assumes that /proc/cpuinfo is never localized.
- */
-
-#include "sys/auxv.h"
-#include "png.h"
-
-static int
-png_have_vsx(png_structp png_ptr)
-{
-
-   const unsigned long auxv = getauxval( AT_HWCAP );
-
-   PNG_UNUSED(png_ptr)
-
-   if(auxv & (PPC_FEATURE_HAS_ALTIVEC|PPC_FEATURE_HAS_VSX ))
-      return 1;
-   else
-      return 0;
-}
-
--- a/contrib/tools/README.txt
+++ b/contrib/tools/README.txt
@@ -23,5 +23,4 @@ ORIGINAL AUTHORS
    of the people below claim any rights with regard to the contents of this
    directory.

-    John Bowler <jbowler at acm.org>
-    Glenn Randers-Pehrson <glennrp at users.sourceforge.net>
+    John Bowler <jbowler@acm.org>
--- a/contrib/tools/pngfix.c
+++ b/contrib/tools/pngfix.c
@@ -2,7 +2,7 @@
 *
 * Copyright (c) 2014-2016 John Cunningham Bowler
 *
- * Last changed in libpng 1.6.26 [October 20, 2016]
+ * Last changed in libpng 1.6.21 [January 15, 2016]
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
@@ -1824,7 +1824,7 @@ IDAT_init(struct IDAT * const idat, struct file * const file)
 }

 static png_uint_32
-rechunk_length(struct IDAT *idat, int start)
+rechunk_length(struct IDAT *idat)
   /* Return the length for the next IDAT chunk, taking into account
    * rechunking.
    */
@@ -1836,7 +1836,7 @@ rechunk_length(struct IDAT *idat, int start)
      const struct IDAT_list *cur;
      unsigned int count;

-      if (start)
+      if (idat->idat_index == 0) /* at the new chunk (first time) */
         return idat->idat_length; /* use the cache */

      /* Otherwise rechunk_length is called at the end of a chunk for the length
@@ -1995,7 +1995,7 @@ process_IDAT(struct file *file)
      idat->idat_index = 0; /* Index into chunk data */

      /* Update the chunk length to the correct value for the IDAT chunk: */
-      file->chunk->chunk_length = rechunk_length(idat, 1/*start*/);
+      file->chunk->chunk_length = rechunk_length(idat);

      /* Change the state to writing IDAT chunks */
      file->state = STATE_IDAT;
@@ -3473,8 +3473,7 @@ read_callback(png_structp png_ptr, png_bytep buffer, size_t count)
                     /* Write another IDAT chunk.  Call rechunk_length to
                      * calculate the length required.
                      */
-                     length = chunk->chunk_length =
-                         rechunk_length(file->idat, 0/*end*/);
+                     length = chunk->chunk_length = rechunk_length(file->idat);
                     assert(type == png_IDAT);
                     file->write_count = 0; /* for the new chunk */
                     --(file->write_count); /* fake out the increment below */
--- 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/libpng-manual.txt
+++ b/libpng-manual.txt
@@ -1,6 +1,6 @@
 libpng-manual.txt - A description on how to use and modify libpng

- libpng version 1.6.30beta01 - April 1, 2017
+ libpng version 1.6.25rc05 - August 30, 2016
 Updated and distributed by Glenn Randers-Pehrson
 <glennrp at users.sourceforge.net>
 Copyright (c) 1998-2016 Glenn Randers-Pehrson
@@ -11,7 +11,7 @@ libpng-manual.txt - A description on how to use and modify libpng

 Based on:

- libpng versions 0.97, January 1998, through 1.6.30beta01 - April 1, 2017
+ libpng versions 0.97, January 1998, through 1.6.25rc05 - August 30, 2016
 Updated and distributed by Glenn Randers-Pehrson
 Copyright (c) 1998-2016 Glenn Randers-Pehrson

@@ -467,9 +467,8 @@ the default, use

 The values for png_set_crc_action() say how libpng is to handle CRC errors in
 ancillary and critical chunks, and whether to use the data contained
-therein. Starting with libpng-1.6.26, this also governs how an ADLER32 error
-is handled while reading the IDAT chunk. Note that it is impossible to
-"discard" data in a critical chunk.
+therein.  Note that it is impossible to "discard" data in a critical
+chunk.

 Choices for (int) crit_action are
   PNG_CRC_DEFAULT      0  error/quit
@@ -486,9 +485,6 @@ Choices for (int) ancil_action are
   PNG_CRC_QUIET_USE    4  quiet/use data
   PNG_CRC_NO_CHANGE    5  use the current value

-When the setting for crit_action is PNG_CRC_QUIET_USE, the CRC and ADLER32
-checksums are not only ignored, but they are not evaluated.
-
 Setting up callback code

 You can set up a callback function to handle any unknown chunks in the
@@ -4246,6 +4242,8 @@ 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
@@ -4257,11 +4255,6 @@ 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.
@@ -5342,9 +5335,8 @@ with an even number of lower-case hex digits, and to make them unsigned
 We prefer to use underscores rather than camelCase in names, except
 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 (something != 0)" and "if (something == 0)"
+over "if (something)" and if "(!something)", respectively.

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

@@ -5358,7 +5350,7 @@ 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 1.6.30beta01 are Y2K compliant.  It is my belief that earlier
+upward through 1.6.25rc05 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 "April 1, 2017"
+.TH LIBPNG 3 "August 30, 2016"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.6.30beta01
+libpng \- Portable Network Graphics (PNG) Reference Library 1.6.25rc05
 .SH SYNOPSIS
 \fB
 #include <png.h>\fP
@@ -510,7 +510,7 @@ Following is a copy of the libpng-manual.txt file that accompanies libpng.
 .SH LIBPNG.TXT
 libpng-manual.txt - A description on how to use and modify libpng

- libpng version 1.6.30beta01 - April 1, 2017
+ libpng version 1.6.25rc05 - August 30, 2016
 Updated and distributed by Glenn Randers-Pehrson
 <glennrp at users.sourceforge.net>
 Copyright (c) 1998-2016 Glenn Randers-Pehrson
@@ -521,7 +521,7 @@ libpng-manual.txt - A description on how to use and modify libpng

 Based on:

- libpng versions 0.97, January 1998, through 1.6.30beta01 - April 1, 2017
+ libpng versions 0.97, January 1998, through 1.6.25rc05 - August 30, 2016
 Updated and distributed by Glenn Randers-Pehrson
 Copyright (c) 1998-2016 Glenn Randers-Pehrson

@@ -977,9 +977,8 @@ the default, use

 The values for png_set_crc_action() say how libpng is to handle CRC errors in
 ancillary and critical chunks, and whether to use the data contained
-therein. Starting with libpng-1.6.26, this also governs how an ADLER32 error
-is handled while reading the IDAT chunk. Note that it is impossible to
-"discard" data in a critical chunk.
+therein.  Note that it is impossible to "discard" data in a critical
+chunk.

 Choices for (int) crit_action are
   PNG_CRC_DEFAULT      0  error/quit
@@ -996,9 +995,6 @@ Choices for (int) ancil_action are
   PNG_CRC_QUIET_USE    4  quiet/use data
   PNG_CRC_NO_CHANGE    5  use the current value

-When the setting for crit_action is PNG_CRC_QUIET_USE, the CRC and ADLER32
-checksums are not only ignored, but they are not evaluated.
-
 .SS Setting up callback code

 You can set up a callback function to handle any unknown chunks in the
@@ -4756,6 +4752,8 @@ 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
@@ -4767,11 +4765,6 @@ 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.
@@ -5852,9 +5845,8 @@ with an even number of lower-case hex digits, and to make them unsigned
 We prefer to use underscores rather than camelCase in names, except
 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 (something != 0)" and "if (something == 0)"
+over "if (something)" and if "(!something)", respectively.

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

@@ -5868,7 +5860,7 @@ 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 1.6.30beta01 are Y2K compliant.  It is my belief that earlier
+upward through 1.6.25rc05 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
@@ -5966,11 +5958,11 @@ the first widely used release:
 ...
 1.0.19                  10    10019  10.so.0.19[.0]
 ...
- 1.2.57                  13    10257  12.so.0.56[.0]
+ 1.2.56                  13    10256  12.so.0.56[.0]
 ...
- 1.5.28                  15    10528  15.so.15.28[.0]
+ 1.5.27                  15    10527  15.so.15.27[.0]
 ...
- 1.6.30                  16    10630  16.so.16.30[.0]
+ 1.6.25                  16    10625  16.so.16.25[.0]

 Henceforth the source version will match the shared-library minor
 and patch numbers; the shared-library major version number will be
@@ -6026,7 +6018,7 @@ possible without all of you.

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

-Libpng version 1.6.30beta01 - April 1, 2017:
+Libpng version 1.6.25rc05 - August 30, 2016:
 Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc.
 Currently maintained by Glenn Randers-Pehrson (glennrp at users.sourceforge.net).

@@ -6051,8 +6043,8 @@ this sentence.

 This code is released under the libpng license.

-libpng versions 1.0.7, July 1, 2000 through 1.6.30beta01, April 1, 2017 are
-Copyright (c) 2000-2002, 2004, 2006-2017 Glenn Randers-Pehrson, are
+libpng versions 1.0.7, July 1, 2000 through 1.6.25rc05, August 30, 2016 are
+Copyright (c) 2000-2002, 2004, 2006-2016 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
 added to the list of Contributing Authors:
@@ -6063,9 +6055,6 @@ added to the list of Contributing Authors:
   Cosmin Truta
   Gilles Vollant
   James Yu
-   Mandar Sahastrabuddhe
-   Google Inc.
-   Vadim Barkov

 and with the following additions to the disclaimer:

@@ -6179,7 +6168,7 @@ files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).

 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-April 1, 2017
+August 30, 2016

 .\" end of man page

--- a/libpngpf.3
+++ b/libpngpf.3
@@ -1,6 +1,6 @@
-.TH LIBPNGPF 3 "April 1, 2017"
+.TH LIBPNGPF 3 "August 30, 2016"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.6.30beta01
+libpng \- Portable Network Graphics (PNG) Reference Library 1.6.25rc05
 (private functions)
 .SH SYNOPSIS
 \fB#include \fI"pngpriv.h"
--- a/mips/filter_msa_intrinsics.c
+++ b/mips/filter_msa_intrinsics.c
@@ -3,7 +3,7 @@
 *
 * Copyright (c) 2016 Glenn Randers-Pehrson
 * Written by Mandar Sahastrabuddhe, August 2016.
- * Last changed in libpng 1.6.25 [September 1, 2016]
+ * Last changed in libpng 1.6.25 [(PENDING RELEASE)]
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
--- a/mips/mips_init.c
+++ b/mips/mips_init.c
@@ -3,7 +3,7 @@
 *
 * Copyright (c) 2016 Glenn Randers-Pehrson
 * Written by Mandar Sahastrabuddhe, 2016.
- * Last changed in libpng 1.6.25 [September 1, 2016]
+ * Last changed in libpng 1.6.25 [(PENDING RELEASE)]
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
--- a/png.5
+++ b/png.5
@@ -1,4 +1,4 @@
-.TH PNG 5 "April 1, 2017"
+.TH PNG 5 "August 30, 2016"
 .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
@@ -1,8 +1,8 @@

 /* png.c - location for general purpose libpng functions
 *
- * Last changed in libpng 1.6.30 [(PENDING RELEASE)]
- * Copyright (c) 1998-2002,2004,2006-2017 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.25 [(PENDING RELEASE)]
+ * Copyright (c) 1998-2002,2004,2006-2016 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.)
 *
@@ -14,7 +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_30beta01 Your_png_h_is_not_version_1_6_30beta01;
+typedef png_libpng_version_1_6_25rc05 Your_png_h_is_not_version_1_6_25rc05;

 /* 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
@@ -458,7 +458,7 @@ png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask,

 #ifdef PNG_TEXT_SUPPORTED
   /* Free text item num or (if num == -1) all text items */
-   if (info_ptr->text != NULL &&
+   if (info_ptr->text != 0 &&
       ((mask & PNG_FREE_TEXT) & info_ptr->free_me) != 0)
   {
      if (num != -1)
@@ -477,7 +477,6 @@ png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask,
         png_free(png_ptr, info_ptr->text);
         info_ptr->text = NULL;
         info_ptr->num_text = 0;
-         info_ptr->max_text = 0;
      }
   }
 #endif
@@ -542,7 +541,7 @@ png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask,

 #ifdef PNG_sPLT_SUPPORTED
   /* Free a given sPLT entry, or (if num == -1) all sPLT entries */
-   if (info_ptr->splt_palettes != NULL &&
+   if (info_ptr->splt_palettes != 0 &&
       ((mask & PNG_FREE_SPLT) & info_ptr->free_me) != 0)
   {
      if (num != -1)
@@ -572,7 +571,7 @@ png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask,
 #endif

 #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
-   if (info_ptr->unknown_chunks != NULL &&
+   if (info_ptr->unknown_chunks != 0 &&
       ((mask & PNG_FREE_UNKN) & info_ptr->free_me) != 0)
   {
      if (num != -1)
@@ -618,7 +617,7 @@ png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask,
   /* Free any image bits attached to the info structure */
   if (((mask & PNG_FREE_ROWS) & info_ptr->free_me) != 0)
   {
-      if (info_ptr->row_pointers != NULL)
+      if (info_ptr->row_pointers != 0)
      {
         png_uint_32 row;
         for (row = 0; row < info_ptr->height; row++)
@@ -685,7 +684,7 @@ png_init_io(png_structrp png_ptr, png_FILE_p fp)
 void PNGAPI
 png_save_int_32(png_bytep buf, png_int_32 i)
 {
-   png_save_uint_32(buf, (png_uint_32)i);
+   png_save_uint_32(buf, i);
 }
 #  endif

@@ -776,15 +775,15 @@ png_get_copyright(png_const_structrp png_ptr)
 #else
 #  ifdef __STDC__
   return PNG_STRING_NEWLINE \
-      "libpng version 1.6.30beta01 - April 1, 2017" PNG_STRING_NEWLINE \
-      "Copyright (c) 1998-2002,2004,2006-2017 Glenn Randers-Pehrson" \
+      "libpng version 1.6.25rc05 - August 30, 2016" PNG_STRING_NEWLINE \
+      "Copyright (c) 1998-2002,2004,2006-2016 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 1.6.30beta01 - April 1, 2017\
-      Copyright (c) 1998-2002,2004,2006-2017 Glenn Randers-Pehrson\
+   return "libpng version 1.6.25rc05 - August 30, 2016\
+      Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson\
      Copyright (c) 1996-1997 Andreas Dilger\
      Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.";
 #  endif
@@ -2530,7 +2529,7 @@ png_check_IHDR(png_const_structrp png_ptr,
      error = 1;
   }

-   if (png_gt(((width + 7) & (~7U)),
+   if (png_gt(((width + 7) & (~7)),
       ((PNG_SIZE_MAX
           - 48        /* big_row_buf hack */
           - 1)        /* filter byte */
@@ -2832,7 +2831,7 @@ 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)
@@ -2910,9 +2909,7 @@ 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;
@@ -2926,10 +2923,7 @@ 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
@@ -2946,7 +2940,7 @@ 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 = (unsigned int)(-exp_b10); /* PLUS 2 digits: TOTAL 3 */
+               czero = -exp_b10; /* PLUS 2 digits: TOTAL 3 */
               exp_b10 = 0;      /* Dot added below before first output. */
            }
            else
@@ -2980,7 +2974,7 @@ 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
@@ -2994,7 +2988,7 @@ 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.
@@ -3021,9 +3015,7 @@ 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)
@@ -3059,26 +3051,21 @@ 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);
@@ -3119,7 +3106,7 @@ 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
@@ -3130,12 +3117,12 @@ 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 = (unsigned int)(-exp_b10);
+                  *ascii++ = 45, --size; /* '-': PLUS 1 TOTAL 3+precision */
+                  uexp_b10 = -exp_b10;
               }

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

               cdigits = 0;

@@ -3197,11 +3184,9 @@ 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 = -fp;
      else
-         num = (png_uint_32)fp;
+         num = fp;

      if (num <= 0x80000000) /* else overflowed */
      {
@@ -3237,10 +3222,7 @@ 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! */
            }
@@ -4277,13 +4259,13 @@ png_set_option(png_structrp png_ptr, int option, int onoff)
   if (png_ptr != NULL && option >= 0 && option < PNG_OPTION_NEXT &&
      (option & 1) == 0)
   {
-      png_uint_32 mask = 3U << option;
-      png_uint_32 setting = (2U + (onoff != 0)) << option;
-      png_uint_32 current = png_ptr->options;
+      int mask = 3 << option;
+      int setting = (2 + (onoff != 0)) << option;
+      int current = png_ptr->options;

-      png_ptr->options = (png_uint_32)(((current & ~mask) | setting) & 0xff);
+      png_ptr->options = (png_byte)(((current & ~mask) | setting) & 0xff);

-      return (int)(current & mask) >> option;
+      return (current & mask) >> option;
   }

   return PNG_OPTION_INVALID;
@@ -4295,7 +4277,7 @@ 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/png.h
+++ b/png.h
@@ -1,9 +1,9 @@

 /* png.h - header file for PNG reference library
 *
- * libpng version 1.6.30beta01, April 1, 2017
+ * libpng version 1.6.25rc05, August 30, 2016
 *
- * Copyright (c) 1998-2002,2004,2006-2017 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2002,2004,2006-2016 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.)
 *
@@ -12,7 +12,7 @@
 * Authors and maintainers:
 *   libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
 *   libpng versions 0.89, June 1996, through 0.96, May 1997: Andreas Dilger
- *   libpng versions 0.97, January 1998, through 1.6.30beta01, April 1, 2017:
+ *   libpng versions 0.97, January 1998, through 1.6.25rc05, August 30, 2016:
 *     Glenn Randers-Pehrson.
 *   See also "Contributing Authors", below.
 */
@@ -25,8 +25,12 @@
 *
 * This code is released under the libpng license.
 *
- * libpng versions 1.0.7, July 1, 2000 through 1.6.30beta01, April 1, 2017 are
- * Copyright (c) 2000-2002, 2004, 2006-2017 Glenn Randers-Pehrson, are
+ * Some files in the "contrib" directory and some configure-generated
+ * files that are distributed with libpng have other copyright owners and
+ * are released under other open source licenses.
+ *
+ * libpng versions 1.0.7, July 1, 2000 through 1.6.25rc05, August 30, 2016 are
+ * Copyright (c) 2000-2002, 2004, 2006-2016 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
 * added to the list of Contributing Authors:
@@ -38,8 +42,6 @@
 *    Gilles Vollant
 *    James Yu
 *    Mandar Sahastrabuddhe
- *    Google Inc.
- *    Vadim Barkov
 *
 * and with the following additions to the disclaimer:
 *
@@ -50,10 +52,10 @@
 *    risk of satisfactory quality, performance, accuracy, and effort is with
 *    the user.
 *
- * Some files in the "contrib" directory and some configure-generated
- * files that are distributed with libpng have other copyright owners and
+ * Some files in the "contrib" directory have other copyright owners and
 * are released under other open source licenses.
 *
+ *
 * libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
 * Copyright (c) 1998-2000 Glenn Randers-Pehrson, are derived from
 * libpng-0.96, and are distributed according to the same disclaimer and
@@ -64,6 +66,9 @@
 *    Glenn Randers-Pehrson
 *    Willem van Schaik
 *
+ * Some files in the "scripts" directory have different copyright owners
+ * but are also released under this license.
+ *
 * libpng versions 0.89, June 1996, through 0.96, May 1997, are
 * Copyright (c) 1996-1997 Andreas Dilger, are derived from libpng-0.88,
 * and are distributed according to the same disclaimer and license as
@@ -209,11 +214,11 @@
 *    ...
 *    1.0.19                  10    10019  10.so.0.19[.0]
 *    ...
- *    1.2.57                  13    10257  12.so.0.57[.0]
+ *    1.2.56                  13    10256  12.so.0.56[.0]
 *    ...
- *    1.5.28                  15    10527  15.so.15.28[.0]
+ *    1.5.27                  15    10527  15.so.15.27[.0]
 *    ...
- *    1.6.30                  16    10630  16.so.16.30[.0]
+ *    1.6.25                  16    10625  16.so.16.25[.0]
 *
 *    Henceforth the source version will match the shared-library major
 *    and minor numbers; the shared-library major version number will be
@@ -234,20 +239,20 @@
 *
 * See libpng.txt or libpng.3 for more information.  The PNG specification
 * is available as a W3C Recommendation and as an ISO Specification,
- * <https://www.w3.org/TR/2003/REC-PNG-20031110/
+ * <http://www.w3.org/TR/2003/REC-PNG-20031110/
 */

 /*
 * Y2K compliance in libpng:
 * =========================
 *
- *    April 1, 2017
+ *    August 30, 2016
 *
 *    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 1.6.30beta01 are Y2K compliant.  It is my belief that
+ *    upward through 1.6.25rc05 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
@@ -309,8 +314,8 @@
 */

 /* Version information for png.h - this should match the version in png.c */
-#define PNG_LIBPNG_VER_STRING "1.6.30beta01"
-#define PNG_HEADER_VERSION_STRING " libpng version 1.6.30beta01 - April 1, 2017\n"
+#define PNG_LIBPNG_VER_STRING "1.6.25rc05"
+#define PNG_HEADER_VERSION_STRING " libpng version 1.6.25rc05 - August 30, 2016\n"

 #define PNG_LIBPNG_VER_SONUM   16
 #define PNG_LIBPNG_VER_DLLNUM  16
@@ -318,13 +323,13 @@
 /* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
 #define PNG_LIBPNG_VER_MAJOR   1
 #define PNG_LIBPNG_VER_MINOR   6
-#define PNG_LIBPNG_VER_RELEASE 30
+#define PNG_LIBPNG_VER_RELEASE 25

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

-#define PNG_LIBPNG_VER_BUILD  01
+#define PNG_LIBPNG_VER_BUILD  05

 /* Release Status */
 #define PNG_LIBPNG_BUILD_ALPHA    1
@@ -341,7 +346,7 @@
 #define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
                                       PNG_LIBPNG_BUILD_PRIVATE */

-#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_BETA
+#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_RC

 /* Careful here.  At one time, Guy wanted to use 082, but that would be octal.
 * We must not include leading zeros.
@@ -349,7 +354,7 @@
 * version 1.0.0 was mis-numbered 100 instead of 10000).  From
 * version 1.0.1 it's    xxyyzz, where x=major, y=minor, z=release
 */
-#define PNG_LIBPNG_VER 10630 /* 1.6.30 */
+#define PNG_LIBPNG_VER 10625 /* 1.6.25 */

 /* Library configuration: these options cannot be changed after
 * the library has been built.
@@ -459,7 +464,7 @@ extern "C" {
 /* This triggers a compiler error in png.c, if png.c and png.h
 * do not agree upon the version number.
 */
-typedef char* png_libpng_version_1_6_30beta01;
+typedef char* png_libpng_version_1_6_25rc05;

 /* Basic control structions.  Read libpng-manual.txt or libpng.3 for more info.
 *
@@ -2753,7 +2758,7 @@ typedef struct
 *
 * 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
@@ -3225,11 +3230,7 @@ PNG_EXPORT(245, int, png_image_write_to_memory, (png_imagep image, void *memory,
 #ifdef PNG_MIPS_MSA_API_SUPPORTED
 #  define PNG_MIPS_MSA   6 /* HARDWARE: MIPS Msa SIMD instructions supported */
 #endif
-#define PNG_IGNORE_ADLER32 8
-#ifdef PNG_POWERPC_VSX_API_SUPPORTED
-#  define PNG_POWERPC_VSX   10 /* HARDWARE: PowerPC VSX SIMD instructions supported */
-#endif
-#define PNG_OPTION_NEXT  12 /* Next option - numbers must be even */
+#define PNG_OPTION_NEXT  8 /* Next option - numbers must be even */

 /* Return values: NOTE: there are four values and 'off' is *not* zero */
 #define PNG_OPTION_UNSET   0 /* Unset - defaults to off */
--- a/pngconf.h
+++ b/pngconf.h
@@ -1,7 +1,7 @@

 /* pngconf.h - machine configurable file for libpng
 *
- * libpng version 1.6.30beta01, April 1, 2017
+ * libpng version 1.6.25rc05, August 30, 2016
 *
 * Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -507,9 +507,9 @@
 #  error "libpng requires a signed 32-bit (or more) type"
 #endif

-#if UINT_MAX > 4294967294U
+#if UINT_MAX > 4294967294
   typedef unsigned int png_uint_32;
-#elif ULONG_MAX > 4294967294U
+#elif ULONG_MAX > 4294967294
   typedef unsigned long int png_uint_32;
 #else
 #  error "libpng requires an unsigned 32-bit (or more) type"
--- a/pngerror.c
+++ b/pngerror.c
@@ -1,7 +1,7 @@

 /* pngerror.c - stub functions for i/o and memory allocation
 *
- * Last changed in libpng 1.6.26 [October 20, 2016]
+ * Last changed in libpng 1.6.24 [August 4, 2016]
 * Copyright (c) 1998-2002,2004,2006-2016 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.)
@@ -573,7 +573,7 @@ png_fixed_error,(png_const_structrp png_ptr, png_const_charp name),PNG_NORETURN)
 {
 #  define fixed_message "fixed point overflow in "
 #  define fixed_message_ln ((sizeof fixed_message)-1)
-   unsigned int  iin;
+   int  iin;
   char msg[fixed_message_ln+PNG_MAX_ERROR_TEXT];
   memcpy(msg, fixed_message, fixed_message_ln);
   iin = 0;
--- a/pngget.c
+++ b/pngget.c
@@ -1,7 +1,7 @@

 /* pngget.c - retrieval of values from info struct
 *
- * Last changed in libpng 1.6.26 [October 20, 2016]
+ * Last changed in libpng 1.6.24 [August 4, 2016]
 * Copyright (c) 1998-2002,2004,2006-2016 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.)
@@ -338,7 +338,7 @@ ppi_from_ppm(png_uint_32 ppm)
   png_fixed_point result;
   if (ppm <= PNG_UINT_31_MAX && png_muldiv(&result, (png_int_32)ppm, 127,
       5000) != 0)
-      return (png_uint_32)result;
+      return result;

   /* Overflow. */
   return 0;
--- a/pngmem.c
+++ b/pngmem.c
@@ -1,7 +1,7 @@

 /* pngmem.c - stub functions for memory allocation
 *
- * Last changed in libpng 1.6.26 [October 20, 2016]
+ * Last changed in libpng 1.6.24 [August 4, 2016%]
 * Copyright (c) 1998-2002,2004,2006-2014,2016 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.)
@@ -109,7 +109,7 @@ static png_voidp
 png_malloc_array_checked(png_const_structrp png_ptr, int nelements,
    size_t element_size)
 {
-   png_alloc_size_t req = (png_alloc_size_t)nelements; /* known to be > 0 */
+   png_alloc_size_t req = nelements; /* known to be > 0 */

   if (req <= PNG_SIZE_MAX/element_size)
      return png_malloc_base(png_ptr, req * element_size);
--- a/pngpread.c
+++ b/pngpread.c
@@ -684,12 +684,7 @@ png_process_IDAT_data(png_structrp png_ptr, png_bytep buffer,
            png_warning(png_ptr, "Truncated compressed data in IDAT");

         else
-         {
-            if (ret == Z_DATA_ERROR)
-               png_benign_error(png_ptr, "IDAT: ADLER32 checksum mismatch");
-            else
-               png_error(png_ptr, "Decompression error in IDAT");
-         }
+            png_error(png_ptr, "Decompression error in IDAT");

         /* Skip the check on unprocessed input */
         return;
--- a/pngpriv.h
+++ b/pngpriv.h
@@ -1,8 +1,8 @@

 /* pngpriv.h - private declarations for use inside libpng
 *
- * Last changed in libpng 1.6.30 [(PENDING RELEASE)]
- * Copyright (c) 1998-2002,2004,2006-2017 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.25 [(PENDING RELEASE)]
+ * Copyright (c) 1998-2002,2004,2006-2016 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.)
 *
@@ -190,50 +190,6 @@
 #  endif
 #endif

-#ifndef PNG_POWERPC_VSX_OPT
-#  if defined(__PPC64__) && defined(__ALTIVEC__) && defined(__VSX__)
-#     define PNG_POWERPC_VSX_OPT 2
-#  else
-#     define PNG_POWERPC_VSX_OPT 0
-#  endif
-#endif
-
-#ifndef PNG_INTEL_SSE_OPT
-#   ifdef PNG_INTEL_SSE
-      /* Only check for SSE if the build configuration has been modified to
-       * enable SSE optimizations.  This means that these optimizations will
-       * be off by default.  See contrib/intel for more details.
-       */
-#     if defined(__SSE4_1__) || defined(__AVX__) || defined(__SSSE3__) || \
-       defined(__SSE2__) || defined(_M_X64) || defined(_M_AMD64) || \
-       (defined(_M_IX86_FP) && _M_IX86_FP >= 2)
-#         define PNG_INTEL_SSE_OPT 1
-#      endif
-#   endif
-#endif
-
-#if PNG_INTEL_SSE_OPT > 0
-#   ifndef PNG_INTEL_SSE_IMPLEMENTATION
-#      if defined(__SSE4_1__) || defined(__AVX__)
-          /* We are not actually using AVX, but checking for AVX is the best
-             way we can detect SSE4.1 and SSSE3 on MSVC.
-          */
-#         define PNG_INTEL_SSE_IMPLEMENTATION 3
-#      elif defined(__SSSE3__)
-#         define PNG_INTEL_SSE_IMPLEMENTATION 2
-#      elif defined(__SSE2__) || defined(_M_X64) || defined(_M_AMD64) || \
-       (defined(_M_IX86_FP) && _M_IX86_FP >= 2)
-#         define PNG_INTEL_SSE_IMPLEMENTATION 1
-#      else
-#         define PNG_INTEL_SSE_IMPLEMENTATION 0
-#      endif
-#   endif
-
-#   if PNG_INTEL_SSE_IMPLEMENTATION > 0
-#      define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_sse2
-#   endif
-#endif
-
 #if PNG_MIPS_MSA_OPT > 0
 #  define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_msa
 #  ifndef PNG_MIPS_MSA_IMPLEMENTATION
@@ -254,11 +210,6 @@
 #  endif
 #endif /* PNG_MIPS_MSA_OPT > 0 */

-#if PNG_POWERPC_VSX_OPT > 0
-#  define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_vsx
-#  define PNG_POWERPC_VSX_IMPLEMENTATION 1
-#endif
-

 /* Is this a build of a DLL where compilation of the object modules requires
 * different preprocessor settings to those required for a simple library?  If
@@ -466,16 +417,7 @@
   static_cast<type>(static_cast<const void*>(value))
 #else
 #  define png_voidcast(type, value) (value)
-#  ifdef _WIN64
-#     ifdef __GNUC__
-         typedef unsigned long long png_ptruint;
-#     else
-         typedef unsigned __int64 png_ptruint;
-#     endif
-#  else
-      typedef unsigned long png_ptruint;
-#  endif
-#  define png_constcast(type, value) ((type)(png_ptruint)(const void*)(value))
+#  define png_constcast(type, value) ((type)(value))
 #  define png_aligncast(type, value) ((void*)(value))
 #  define png_aligncastconst(type, value) ((const void*)(value))
 #endif /* __cplusplus */
@@ -591,8 +533,7 @@
 /* This implicitly assumes alignment is always to a power of 2. */
 #ifdef png_alignof
 #  define png_isaligned(ptr, type)\
-   (((type)((const char*)ptr-(const char*)0) & \
-   (type)(png_alignof(type)-1)) == 0)
+   ((((const char*)ptr-(const char*)0) & (png_alignof(type)-1)) == 0)
 #else
 #  define png_isaligned(ptr, type) 0
 #endif
@@ -609,92 +550,92 @@
 * are defined in png.h because they need to be visible to applications
 * that call png_set_unknown_chunk().
 */
-/* #define PNG_HAVE_IHDR            0x01U (defined in png.h) */
-/* #define PNG_HAVE_PLTE            0x02U (defined in png.h) */
-#define PNG_HAVE_IDAT               0x04U
-/* #define PNG_AFTER_IDAT           0x08U (defined in png.h) */
-#define PNG_HAVE_IEND               0x10U
-                   /*               0x20U (unused) */
-                   /*               0x40U (unused) */
-                   /*               0x80U (unused) */
-#define PNG_HAVE_CHUNK_HEADER      0x100U
-#define PNG_WROTE_tIME             0x200U
-#define PNG_WROTE_INFO_BEFORE_PLTE 0x400U
-#define PNG_BACKGROUND_IS_GRAY     0x800U
-#define PNG_HAVE_PNG_SIGNATURE    0x1000U
-#define PNG_HAVE_CHUNK_AFTER_IDAT 0x2000U /* Have another chunk after IDAT */
-                   /*             0x4000U (unused) */
-#define PNG_IS_READ_STRUCT        0x8000U /* Else is a write struct */
+/* #define PNG_HAVE_IHDR            0x01 (defined in png.h) */
+/* #define PNG_HAVE_PLTE            0x02 (defined in png.h) */
+#define PNG_HAVE_IDAT               0x04
+/* #define PNG_AFTER_IDAT           0x08 (defined in png.h) */
+#define PNG_HAVE_IEND               0x10
+                   /*               0x20 (unused) */
+                   /*               0x40 (unused) */
+                   /*               0x80 (unused) */
+#define PNG_HAVE_CHUNK_HEADER      0x100
+#define PNG_WROTE_tIME             0x200
+#define PNG_WROTE_INFO_BEFORE_PLTE 0x400
+#define PNG_BACKGROUND_IS_GRAY     0x800
+#define PNG_HAVE_PNG_SIGNATURE    0x1000
+#define PNG_HAVE_CHUNK_AFTER_IDAT 0x2000 /* Have another chunk after IDAT */
+                   /*             0x4000 (unused) */
+#define PNG_IS_READ_STRUCT        0x8000 /* Else is a write struct */

 /* Flags for the transformations the PNG library does on the image data */
-#define PNG_BGR                 0x0001U
-#define PNG_INTERLACE           0x0002U
-#define PNG_PACK                0x0004U
-#define PNG_SHIFT               0x0008U
-#define PNG_SWAP_BYTES          0x0010U
-#define PNG_INVERT_MONO         0x0020U
-#define PNG_QUANTIZE            0x0040U
-#define PNG_COMPOSE             0x0080U    /* Was PNG_BACKGROUND */
-#define PNG_BACKGROUND_EXPAND   0x0100U
-#define PNG_EXPAND_16           0x0200U    /* Added to libpng 1.5.2 */
-#define PNG_16_TO_8             0x0400U    /* Becomes 'chop' in 1.5.4 */
-#define PNG_RGBA                0x0800U
-#define PNG_EXPAND              0x1000U
-#define PNG_GAMMA               0x2000U
-#define PNG_GRAY_TO_RGB         0x4000U
-#define PNG_FILLER              0x8000U
-#define PNG_PACKSWAP           0x10000U
-#define PNG_SWAP_ALPHA         0x20000U
-#define PNG_STRIP_ALPHA        0x40000U
-#define PNG_INVERT_ALPHA       0x80000U
-#define PNG_USER_TRANSFORM    0x100000U
-#define PNG_RGB_TO_GRAY_ERR   0x200000U
-#define PNG_RGB_TO_GRAY_WARN  0x400000U
-#define PNG_RGB_TO_GRAY       0x600000U /* two bits, RGB_TO_GRAY_ERR|WARN */
-#define PNG_ENCODE_ALPHA      0x800000U /* Added to libpng-1.5.4 */
-#define PNG_ADD_ALPHA        0x1000000U /* Added to libpng-1.2.7 */
-#define PNG_EXPAND_tRNS      0x2000000U /* Added to libpng-1.2.9 */
-#define PNG_SCALE_16_TO_8    0x4000000U /* Added to libpng-1.5.4 */
-                       /*    0x8000000U unused */
-                       /*   0x10000000U unused */
-                       /*   0x20000000U unused */
-                       /*   0x40000000U unused */
+#define PNG_BGR                 0x0001
+#define PNG_INTERLACE           0x0002
+#define PNG_PACK                0x0004
+#define PNG_SHIFT               0x0008
+#define PNG_SWAP_BYTES          0x0010
+#define PNG_INVERT_MONO         0x0020
+#define PNG_QUANTIZE            0x0040
+#define PNG_COMPOSE             0x0080     /* Was PNG_BACKGROUND */
+#define PNG_BACKGROUND_EXPAND   0x0100
+#define PNG_EXPAND_16           0x0200     /* Added to libpng 1.5.2 */
+#define PNG_16_TO_8             0x0400     /* Becomes 'chop' in 1.5.4 */
+#define PNG_RGBA                0x0800
+#define PNG_EXPAND              0x1000
+#define PNG_GAMMA               0x2000
+#define PNG_GRAY_TO_RGB         0x4000
+#define PNG_FILLER              0x8000
+#define PNG_PACKSWAP           0x10000
+#define PNG_SWAP_ALPHA         0x20000
+#define PNG_STRIP_ALPHA        0x40000
+#define PNG_INVERT_ALPHA       0x80000
+#define PNG_USER_TRANSFORM    0x100000
+#define PNG_RGB_TO_GRAY_ERR   0x200000
+#define PNG_RGB_TO_GRAY_WARN  0x400000
+#define PNG_RGB_TO_GRAY       0x600000 /* two bits, RGB_TO_GRAY_ERR|WARN */
+#define PNG_ENCODE_ALPHA      0x800000 /* Added to libpng-1.5.4 */
+#define PNG_ADD_ALPHA        0x1000000 /* Added to libpng-1.2.7 */
+#define PNG_EXPAND_tRNS      0x2000000 /* Added to libpng-1.2.9 */
+#define PNG_SCALE_16_TO_8    0x4000000 /* Added to libpng-1.5.4 */
+                       /*    0x8000000 unused */
+                       /*   0x10000000 unused */
+                       /*   0x20000000 unused */
+                       /*   0x40000000 unused */
 /* Flags for png_create_struct */
-#define PNG_STRUCT_PNG   0x0001U
-#define PNG_STRUCT_INFO  0x0002U
+#define PNG_STRUCT_PNG   0x0001
+#define PNG_STRUCT_INFO  0x0002

 /* Flags for the png_ptr->flags rather than declaring a byte for each one */
-#define PNG_FLAG_ZLIB_CUSTOM_STRATEGY     0x0001U
-#define PNG_FLAG_ZSTREAM_INITIALIZED      0x0002U /* Added to libpng-1.6.0 */
-                                  /*      0x0004U    unused */
-#define PNG_FLAG_ZSTREAM_ENDED            0x0008U /* Added to libpng-1.6.0 */
-                                  /*      0x0010U    unused */
-                                  /*      0x0020U    unused */
-#define PNG_FLAG_ROW_INIT                 0x0040U
-#define PNG_FLAG_FILLER_AFTER             0x0080U
-#define PNG_FLAG_CRC_ANCILLARY_USE        0x0100U
-#define PNG_FLAG_CRC_ANCILLARY_NOWARN     0x0200U
-#define PNG_FLAG_CRC_CRITICAL_USE         0x0400U
-#define PNG_FLAG_CRC_CRITICAL_IGNORE      0x0800U
-#define PNG_FLAG_ASSUME_sRGB              0x1000U /* Added to libpng-1.5.4 */
-#define PNG_FLAG_OPTIMIZE_ALPHA           0x2000U /* Added to libpng-1.5.4 */
-#define PNG_FLAG_DETECT_UNINITIALIZED     0x4000U /* Added to libpng-1.5.4 */
-/* #define PNG_FLAG_KEEP_UNKNOWN_CHUNKS      0x8000U */
-/* #define PNG_FLAG_KEEP_UNSAFE_CHUNKS      0x10000U */
-#define PNG_FLAG_LIBRARY_MISMATCH        0x20000U
-#define PNG_FLAG_STRIP_ERROR_NUMBERS     0x40000U
-#define PNG_FLAG_STRIP_ERROR_TEXT        0x80000U
-#define PNG_FLAG_BENIGN_ERRORS_WARN     0x100000U /* Added to libpng-1.4.0 */
-#define PNG_FLAG_APP_WARNINGS_WARN      0x200000U /* Added to libpng-1.6.0 */
-#define PNG_FLAG_APP_ERRORS_WARN        0x400000U /* Added to libpng-1.6.0 */
-                                  /*    0x800000U    unused */
-                                  /*   0x1000000U    unused */
-                                  /*   0x2000000U    unused */
-                                  /*   0x4000000U    unused */
-                                  /*   0x8000000U    unused */
-                                  /*  0x10000000U    unused */
-                                  /*  0x20000000U    unused */
-                                  /*  0x40000000U    unused */
+#define PNG_FLAG_ZLIB_CUSTOM_STRATEGY     0x0001
+#define PNG_FLAG_ZSTREAM_INITIALIZED      0x0002 /* Added to libpng-1.6.0 */
+                                  /*      0x0004    unused */
+#define PNG_FLAG_ZSTREAM_ENDED            0x0008 /* Added to libpng-1.6.0 */
+                                  /*      0x0010    unused */
+                                  /*      0x0020    unused */
+#define PNG_FLAG_ROW_INIT                 0x0040
+#define PNG_FLAG_FILLER_AFTER             0x0080
+#define PNG_FLAG_CRC_ANCILLARY_USE        0x0100
+#define PNG_FLAG_CRC_ANCILLARY_NOWARN     0x0200
+#define PNG_FLAG_CRC_CRITICAL_USE         0x0400
+#define PNG_FLAG_CRC_CRITICAL_IGNORE      0x0800
+#define PNG_FLAG_ASSUME_sRGB              0x1000 /* Added to libpng-1.5.4 */
+#define PNG_FLAG_OPTIMIZE_ALPHA           0x2000 /* Added to libpng-1.5.4 */
+#define PNG_FLAG_DETECT_UNINITIALIZED     0x4000 /* Added to libpng-1.5.4 */
+/* #define PNG_FLAG_KEEP_UNKNOWN_CHUNKS      0x8000 */
+/* #define PNG_FLAG_KEEP_UNSAFE_CHUNKS      0x10000 */
+#define PNG_FLAG_LIBRARY_MISMATCH        0x20000
+#define PNG_FLAG_STRIP_ERROR_NUMBERS     0x40000
+#define PNG_FLAG_STRIP_ERROR_TEXT        0x80000
+#define PNG_FLAG_BENIGN_ERRORS_WARN     0x100000 /* Added to libpng-1.4.0 */
+#define PNG_FLAG_APP_WARNINGS_WARN      0x200000 /* Added to libpng-1.6.0 */
+#define PNG_FLAG_APP_ERRORS_WARN        0x400000 /* Added to libpng-1.6.0 */
+                                  /*    0x800000    unused */
+                                  /*   0x1000000    unused */
+                                  /*   0x2000000    unused */
+                                  /*   0x4000000    unused */
+                                  /*   0x8000000    unused */
+                                  /*  0x10000000    unused */
+                                  /*  0x20000000    unused */
+                                  /*  0x40000000    unused */

 #define PNG_FLAG_CRC_ANCILLARY_MASK (PNG_FLAG_CRC_ANCILLARY_USE | \
                                     PNG_FLAG_CRC_ANCILLARY_NOWARN)
@@ -728,24 +669,6 @@
    ((png_size_t)(width) * (((png_size_t)(pixel_bits)) >> 3)) : \
    (( ((png_size_t)(width) * ((png_size_t)(pixel_bits))) + 7) >> 3) )

-/* This returns the number of trailing bits in the last byte of a row, 0 if the
- * last byte is completely full of pixels.  It is, in principle, (pixel_bits x
- * width) % 8, but that would overflow for large 'width'.  The second macro is
- * the same except that it returns the number of unused bits in the last byte;
- * (8-TRAILBITS), but 0 when TRAILBITS is 0.
- *
- * NOTE: these macros are intended to be self-evidently correct and never
- * overflow on the assumption that pixel_bits is in the range 0..255.  The
- * arguments are evaluated only once and they can be signed (e.g. as a result of
- * the integral promotions).  The result of the expression always has type
- * (png_uint_32), however the compiler always knows it is in the range 0..7.
- */
-#define PNG_TRAILBITS(pixel_bits, width) \
-    (((pixel_bits) * ((width) % (png_uint_32)8)) % 8)
-
-#define PNG_PADBITS(pixel_bits, width) \
-    ((8 - PNG_TRAILBITS(pixel_bits, width)) % 8)
-
 /* PNG_OUT_OF_RANGE returns true if value is outside the range
 * ideal-delta..ideal+delta.  Each argument is evaluated twice.
 * "ideal" and "delta" should be constants, normally simple
@@ -1314,38 +1237,6 @@ PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_msa,(png_row_infop
    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
 #endif

-#if PNG_POWERPC_VSX_OPT > 0
-PNG_INTERNAL_FUNCTION(void,png_read_filter_row_up_vsx,(png_row_infop row_info,
-    png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
-PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_vsx,(png_row_infop
-    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
-PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_vsx,(png_row_infop
-    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
-PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_vsx,(png_row_infop
-    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
-PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_vsx,(png_row_infop
-    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
-PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_vsx,(png_row_infop
-    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
-PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_vsx,(png_row_infop
-    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
-#endif
-
-#if PNG_INTEL_SSE_IMPLEMENTATION > 0
-PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_sse2,(png_row_infop
-    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
-PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_sse2,(png_row_infop
-    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
-PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_sse2,(png_row_infop
-    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
-PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_sse2,(png_row_infop
-    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
-PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_sse2,(png_row_infop
-    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
-PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_sse2,(png_row_infop
-    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
-#endif
-
 /* Choose the best filter to use and filter the row data */
 PNG_INTERNAL_FUNCTION(void,png_write_find_filter,(png_structrp png_ptr,
    png_row_infop row_info),PNG_EMPTY);
@@ -1372,7 +1263,7 @@ PNG_INTERNAL_FUNCTION(void,png_read_finish_row,(png_structrp png_ptr),
 /* Initialize the row buffers, etc. */
 PNG_INTERNAL_FUNCTION(void,png_read_start_row,(png_structrp png_ptr),PNG_EMPTY);

-#if ZLIB_VERNUM >= 0x1240
+#if PNG_ZLIB_VERNUM >= 0x1240
 PNG_INTERNAL_FUNCTION(int,png_zlib_inflate,(png_structrp png_ptr, int flush),
      PNG_EMPTY);
 #  define PNG_INFLATE(pp, flush) png_zlib_inflate(pp, flush)
@@ -2081,11 +1972,6 @@ PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_neon,
 PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_msa,
   (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
 #endif
-
-#  if PNG_INTEL_SSE_IMPLEMENTATION > 0
-PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_sse2,
-   (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
-#  endif
 #endif

 PNG_INTERNAL_FUNCTION(png_uint_32, png_check_keyword, (png_structrp png_ptr,
--- a/pngread.c
+++ b/pngread.c
@@ -1,7 +1,7 @@

 /* pngread.c - read a PNG file
 *
- * Last changed in libpng 1.6.26 [October 20, 2016]
+ * Last changed in libpng 1.6.24 [August 4, 2016]
 * Copyright (c) 1998-2002,2004,2006-2016 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.)
@@ -359,9 +359,9 @@ png_do_read_intrapixel(png_row_infop row_info, png_bytep row)

         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
         {
-            png_uint_32 s0   = (png_uint_32)(*(rp    ) << 8) | *(rp + 1);
-            png_uint_32 s1   = (png_uint_32)(*(rp + 2) << 8) | *(rp + 3);
-            png_uint_32 s2   = (png_uint_32)(*(rp + 4) << 8) | *(rp + 5);
+            png_uint_32 s0   = (*(rp    ) << 8) | *(rp + 1);
+            png_uint_32 s1   = (*(rp + 2) << 8) | *(rp + 3);
+            png_uint_32 s2   = (*(rp + 4) << 8) | *(rp + 5);
            png_uint_32 red  = (s0 + s1 + 65536) & 0xffff;
            png_uint_32 blue = (s2 + s1 + 65536) & 0xffff;
            *(rp    ) = (png_byte)((red >> 8) & 0xff);
@@ -1393,9 +1393,7 @@ png_image_read_header(png_voidp argument)
   png_structrp png_ptr = image->opaque->png_ptr;
   png_inforp info_ptr = image->opaque->info_ptr;

-#ifdef PNG_BENIGN_ERRORS_SUPPORTED
   png_set_benign_errors(png_ptr, 1/*warn*/);
-#endif
   png_read_info(png_ptr, info_ptr);

   /* Do this the fast way; just read directly out of png_struct. */
@@ -1433,7 +1431,7 @@ png_image_read_header(png_voidp argument)
            break;

         case PNG_COLOR_TYPE_PALETTE:
-            cmap_entries = (png_uint_32)png_ptr->num_palette;
+            cmap_entries = png_ptr->num_palette;
            break;

         default:
@@ -1968,7 +1966,7 @@ make_gray_file_colormap(png_image_read_control *display)
   for (i=0; i<256; ++i)
      png_create_colormap_entry(display, i, i, i, i, 255, P_FILE);

-   return (int)i;
+   return i;
 }

 static int
@@ -1979,7 +1977,7 @@ make_gray_colormap(png_image_read_control *display)
   for (i=0; i<256; ++i)
      png_create_colormap_entry(display, i, i, i, i, 255, P_sRGB);

-   return (int)i;
+   return i;
 }
 #define PNG_GRAY_COLORMAP_ENTRIES 256

@@ -2033,7 +2031,7 @@ make_ga_colormap(png_image_read_control *display)
             P_sRGB);
   }

-   return (int)i;
+   return i;
 }

 #define PNG_GA_COLORMAP_ENTRIES 256
@@ -2058,7 +2056,7 @@ make_rgb_colormap(png_image_read_control *display)
      }
   }

-   return (int)i;
+   return i;
 }

 #define PNG_RGB_COLORMAP_ENTRIES 216
@@ -2251,7 +2249,7 @@ png_image_read_colormap(png_voidp argument)
            if (PNG_GRAY_COLORMAP_ENTRIES > image->colormap_entries)
               png_error(png_ptr, "gray[16] color-map: too few entries");

-            cmap_entries = (unsigned int)make_gray_colormap(display);
+            cmap_entries = make_gray_colormap(display);

            if (png_ptr->num_trans > 0)
            {
@@ -2349,7 +2347,7 @@ png_image_read_colormap(png_voidp argument)
            if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries)
               png_error(png_ptr, "gray+alpha color-map: too few entries");

-            cmap_entries = (unsigned int)make_ga_colormap(display);
+            cmap_entries = make_ga_colormap(display);

            background_index = PNG_CMAP_GA_BACKGROUND;
            output_processing = PNG_CMAP_GA;
@@ -2383,7 +2381,7 @@ png_image_read_colormap(png_voidp argument)
               if (PNG_GRAY_COLORMAP_ENTRIES > image->colormap_entries)
                  png_error(png_ptr, "gray-alpha color-map: too few entries");

-               cmap_entries = (unsigned int)make_gray_colormap(display);
+               cmap_entries = make_gray_colormap(display);

               if (output_encoding == P_LINEAR)
               {
@@ -2522,7 +2520,7 @@ png_image_read_colormap(png_voidp argument)
               if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries)
                  png_error(png_ptr, "rgb[ga] color-map: too few entries");

-               cmap_entries = (unsigned int)make_ga_colormap(display);
+               cmap_entries = make_ga_colormap(display);
               background_index = PNG_CMAP_GA_BACKGROUND;
               output_processing = PNG_CMAP_GA;
            }
@@ -2548,12 +2546,12 @@ png_image_read_colormap(png_voidp argument)
                  png_ptr->num_trans > 0) &&
                  png_gamma_not_sRGB(png_ptr->colorspace.gamma) != 0)
               {
-                  cmap_entries = (unsigned int)make_gray_file_colormap(display);
+                  cmap_entries = make_gray_file_colormap(display);
                  data_encoding = P_FILE;
               }

               else
-                  cmap_entries = (unsigned int)make_gray_colormap(display);
+                  cmap_entries = make_gray_colormap(display);

               /* But if the input has alpha or transparency it must be removed
                */
@@ -2641,7 +2639,7 @@ png_image_read_colormap(png_voidp argument)
                  if (PNG_RGB_COLORMAP_ENTRIES+1+27 > image->colormap_entries)
                     png_error(png_ptr, "rgb+alpha color-map: too few entries");

-                  cmap_entries = (unsigned int)make_rgb_colormap(display);
+                  cmap_entries = make_rgb_colormap(display);

                  /* Add a transparent entry. */
                  png_create_colormap_entry(display, cmap_entries, 255, 255,
@@ -2690,7 +2688,7 @@ png_image_read_colormap(png_voidp argument)
                  if (PNG_RGB_COLORMAP_ENTRIES+1+27 > image->colormap_entries)
                     png_error(png_ptr, "rgb-alpha color-map: too few entries");

-                  cmap_entries = (unsigned int)make_rgb_colormap(display);
+                  cmap_entries = make_rgb_colormap(display);

                  png_create_colormap_entry(display, cmap_entries, back_r,
                      back_g, back_b, 0/*unused*/, output_encoding);
@@ -2775,7 +2773,7 @@ png_image_read_colormap(png_voidp argument)
               if (PNG_RGB_COLORMAP_ENTRIES > image->colormap_entries)
                  png_error(png_ptr, "rgb color-map: too few entries");

-               cmap_entries = (unsigned int)make_rgb_colormap(display);
+               cmap_entries = make_rgb_colormap(display);
               output_processing = PNG_CMAP_RGB;
            }
         }
@@ -2799,11 +2797,11 @@ png_image_read_colormap(png_voidp argument)

            output_processing = PNG_CMAP_NONE;
            data_encoding = P_FILE; /* Don't change from color-map indices */
-            cmap_entries = (unsigned int)png_ptr->num_palette;
+            cmap_entries = png_ptr->num_palette;
            if (cmap_entries > 256)
               cmap_entries = 256;

-            if (cmap_entries > (unsigned int)image->colormap_entries)
+            if (cmap_entries > image->colormap_entries)
               png_error(png_ptr, "palette color-map: too few entries");

            for (i=0; i < cmap_entries; ++i)
@@ -2915,7 +2913,7 @@ png_image_read_colormap(png_voidp argument)
         png_error(png_ptr, "bad background index (internal error)");
   }

-   display->colormap_processing = (int)output_processing;
+   display->colormap_processing = output_processing;

   return 1/*ok*/;
 }
@@ -3224,14 +3222,14 @@ png_image_read_colormapped(png_voidp argument)

   else
   {
-      png_alloc_size_t row_bytes = (png_alloc_size_t)display->row_bytes;
+      png_alloc_size_t row_bytes = display->row_bytes;

      while (--passes >= 0)
      {
         png_uint_32      y = image->height;
         png_bytep        row = png_voidcast(png_bytep, display->first_row);

-         for (; y > 0; --y)
+         while (y-- > 0)
         {
            png_read_row(png_ptr, row, NULL);
            row += row_bytes;
@@ -3559,9 +3557,8 @@ png_image_read_background(png_voidp argument)
             * stride which was multiplied by 2 (below) to get row_bytes.
             */
            ptrdiff_t    step_row = display->row_bytes / 2;
-            unsigned int preserve_alpha = (image->format &
-                PNG_FORMAT_FLAG_ALPHA) != 0;
-            unsigned int outchannels = 1U+preserve_alpha;
+            int preserve_alpha = (image->format & PNG_FORMAT_FLAG_ALPHA) != 0;
+            unsigned int outchannels = 1+preserve_alpha;
            int swap_alpha = 0;

 #           ifdef PNG_SIMPLIFIED_READ_AFIRST_SUPPORTED
@@ -4058,14 +4055,14 @@ png_image_read_direct(png_voidp argument)

   else
   {
-      png_alloc_size_t row_bytes = (png_alloc_size_t)display->row_bytes;
+      png_alloc_size_t row_bytes = display->row_bytes;

      while (--passes >= 0)
      {
         png_uint_32      y = image->height;
         png_bytep        row = png_voidcast(png_bytep, display->first_row);

-         for (; y > 0; --y)
+         while (y-- > 0)
         {
            png_read_row(png_ptr, row, NULL);
            row += row_bytes;
@@ -4094,7 +4091,7 @@ png_image_finish_read(png_imagep image, png_const_colorp background,
       * bits; this is just to verify that the 'row_stride' argument can be
       * represented.
       */
-      if (image->width <= 0x7fffffffU/channels) /* no overflow */
+      if (image->width <= 0x7FFFFFFFU/channels) /* no overflow */
      {
         png_uint_32 check;
         const png_uint_32 png_row_stride = image->width * channels;
@@ -4103,10 +4100,10 @@ png_image_finish_read(png_imagep image, png_const_colorp background,
            row_stride = (png_int_32)/*SAFE*/png_row_stride;

         if (row_stride < 0)
-            check = (png_uint_32)(-row_stride);
+            check = -row_stride;

         else
-            check = (png_uint_32)row_stride;
+            check = row_stride;

         /* This verifies 'check', the absolute value of the actual stride
          * passed in and detects overflow in the application calculation (i.e.
@@ -4131,7 +4128,7 @@ png_image_finish_read(png_imagep image, png_const_colorp background,
             * accomodated on 64-bit systems.
             */
            if (image->height <=
-                0xffffffffU/PNG_IMAGE_PIXEL_COMPONENT_SIZE(image->format)/check)
+                0xFFFFFFFFU/PNG_IMAGE_PIXEL_COMPONENT_SIZE(image->format)/check)
            {
               if ((image->format & PNG_FORMAT_FLAG_COLORMAP) == 0 ||
                  (image->colormap_entries > 0 && colormap != NULL))
--- a/pngrtran.c
+++ b/pngrtran.c
@@ -1,8 +1,8 @@

 /* pngrtran.c - transforms the data in a row for PNG readers
 *
- * Last changed in libpng 1.6.30 [(PENDING RELEASE)]
- * Copyright (c) 1998-2002,2004,2006-2017 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.24 [August 4, 2016]
+ * Copyright (c) 1998-2002,2004,2006-2016 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.)
 *
@@ -429,7 +429,7 @@ png_set_quantize(png_structrp png_ptr, png_colorp palette,
      int i;

      png_ptr->quantize_index = (png_bytep)png_malloc(png_ptr,
-          (png_uint_32)((png_uint_32)num_palette * (sizeof (png_byte))));
+          (png_uint_32)(num_palette * (sizeof (png_byte))));
      for (i = 0; i < num_palette; i++)
         png_ptr->quantize_index[i] = (png_byte)i;
   }
@@ -446,7 +446,7 @@ png_set_quantize(png_structrp png_ptr, png_colorp palette,

         /* Initialize an array to sort colors */
         png_ptr->quantize_sort = (png_bytep)png_malloc(png_ptr,
-             (png_uint_32)((png_uint_32)num_palette * (sizeof (png_byte))));
+             (png_uint_32)(num_palette * (sizeof (png_byte))));

         /* Initialize the quantize_sort array */
         for (i = 0; i < num_palette; i++)
@@ -580,9 +580,9 @@ png_set_quantize(png_structrp png_ptr, png_colorp palette,

         /* Initialize palette index arrays */
         png_ptr->index_to_palette = (png_bytep)png_malloc(png_ptr,
-             (png_uint_32)((png_uint_32)num_palette * (sizeof (png_byte))));
+             (png_uint_32)(num_palette * (sizeof (png_byte))));
         png_ptr->palette_to_index = (png_bytep)png_malloc(png_ptr,
-             (png_uint_32)((png_uint_32)num_palette * (sizeof (png_byte))));
+             (png_uint_32)(num_palette * (sizeof (png_byte))));

         /* Initialize the sort array */
         for (i = 0; i < num_palette; i++)
@@ -2150,7 +2150,7 @@ png_do_unpack(png_row_infop row_info, png_bytep row)
         {
            png_bytep sp = row + (png_size_t)((row_width - 1) >> 3);
            png_bytep dp = row + (png_size_t)row_width - 1;
-            png_uint_32 shift = 7U - ((row_width + 7U) & 0x07);
+            png_uint_32 shift = 7 - (int)((row_width + 7) & 0x07);
            for (i = 0; i < row_width; i++)
            {
               *dp = (png_byte)((*sp >> shift) & 0x01);
@@ -2174,7 +2174,7 @@ png_do_unpack(png_row_infop row_info, png_bytep row)

            png_bytep sp = row + (png_size_t)((row_width - 1) >> 2);
            png_bytep dp = row + (png_size_t)row_width - 1;
-            png_uint_32 shift = ((3U - ((row_width + 3U) & 0x03)) << 1);
+            png_uint_32 shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
            for (i = 0; i < row_width; i++)
            {
               *dp = (png_byte)((*sp >> shift) & 0x03);
@@ -2197,7 +2197,7 @@ png_do_unpack(png_row_infop row_info, png_bytep row)
         {
            png_bytep sp = row + (png_size_t)((row_width - 1) >> 1);
            png_bytep dp = row + (png_size_t)row_width - 1;
-            png_uint_32 shift = ((1U - ((row_width + 1U) & 0x01)) << 2);
+            png_uint_32 shift = (int)((1 - ((row_width + 1) & 0x01)) << 2);
            for (i = 0; i < row_width; i++)
            {
               *dp = (png_byte)((*sp >> shift) & 0x0f);
@@ -2934,7 +2934,7 @@ png_do_gray_to_rgb(png_row_infop row_info, png_bytep row)
 * using the equation given in Poynton's ColorFAQ of 1998-01-04 at
 * <http://www.inforamp.net/~poynton/>  (THIS LINK IS DEAD June 2008 but
 * versions dated 1998 through November 2002 have been archived at
- * https://web.archive.org/web/20000816232553/www.inforamp.net/
+ * http://web.archive.org/web/20000816232553/http://www.inforamp.net/
 * ~poynton/notes/colour_and_gamma/ColorFAQ.txt )
 * Charles Poynton poynton at poynton.com
 *
@@ -3223,8 +3223,7 @@ png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
                        == png_ptr->trans_color.gray)
                     {
                        unsigned int tmp = *sp & (0x7f7f >> (7 - shift));
-                        tmp |=
-                            (unsigned int)(png_ptr->background.gray << shift);
+                        tmp |= png_ptr->background.gray << shift;
                        *sp = (png_byte)(tmp & 0xff);
                     }

@@ -3253,8 +3252,7 @@ png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
                            == png_ptr->trans_color.gray)
                        {
                           unsigned int tmp = *sp & (0x3f3f >> (6 - shift));
-                           tmp |=
-                              (unsigned int)png_ptr->background.gray << shift;
+                           tmp |= png_ptr->background.gray << shift;
                           *sp = (png_byte)(tmp & 0xff);
                        }

@@ -3264,7 +3262,7 @@ png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
                           unsigned int g = (gamma_table [p | (p << 2) |
                               (p << 4) | (p << 6)] >> 6) & 0x03;
                           unsigned int tmp = *sp & (0x3f3f >> (6 - shift));
-                           tmp |= (unsigned int)(g << shift);
+                           tmp |= g << shift;
                           *sp = (png_byte)(tmp & 0xff);
                        }

@@ -3290,8 +3288,7 @@ png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
                            == png_ptr->trans_color.gray)
                        {
                           unsigned int tmp = *sp & (0x3f3f >> (6 - shift));
-                           tmp |=
-                               (unsigned int)png_ptr->background.gray << shift;
+                           tmp |= png_ptr->background.gray << shift;
                           *sp = (png_byte)(tmp & 0xff);
                        }

@@ -3321,8 +3318,7 @@ png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
                            == png_ptr->trans_color.gray)
                        {
                           unsigned int tmp = *sp & (0x0f0f >> (4 - shift));
-                           tmp |= 
-                              (unsigned int)(png_ptr->background.gray << shift);
+                           tmp |= png_ptr->background.gray << shift;
                           *sp = (png_byte)(tmp & 0xff);
                        }

@@ -3332,7 +3328,7 @@ png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
                           unsigned int g = (gamma_table[p | (p << 4)] >> 4) &
                              0x0f;
                           unsigned int tmp = *sp & (0x0f0f >> (4 - shift));
-                           tmp |= (unsigned int)(g << shift);
+                           tmp |= g << shift;
                           *sp = (png_byte)(tmp & 0xff);
                        }

@@ -3358,8 +3354,7 @@ png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
                            == png_ptr->trans_color.gray)
                        {
                           unsigned int tmp = *sp & (0x0f0f >> (4 - shift));
-                           tmp |=
-                              (unsigned int)(png_ptr->background.gray << shift);
+                           tmp |= png_ptr->background.gray << shift;
                           *sp = (png_byte)(tmp & 0xff);
                        }

@@ -4302,7 +4297,7 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row,
            if (num_trans > 0)
            {
               sp = row + (png_size_t)row_width - 1;
-               dp = row + ((png_size_t)row_width << 2) - 1;
+               dp = row + (png_size_t)(row_width << 2) - 1;

               for (i = 0; i < row_width; i++)
               {
@@ -4463,7 +4458,7 @@ png_do_expand(png_row_infop row_info, png_bytep row,
            {
               gray = gray & 0xff;
               sp = row + (png_size_t)row_width - 1;
-               dp = row + ((png_size_t)row_width << 1) - 1;
+               dp = row + (png_size_t)(row_width << 1) - 1;

               for (i = 0; i < row_width; i++)
               {
@@ -4519,7 +4514,7 @@ png_do_expand(png_row_infop row_info, png_bytep row,
            png_byte green = (png_byte)(trans_color->green & 0xff);
            png_byte blue = (png_byte)(trans_color->blue & 0xff);
            sp = row + (png_size_t)row_info->rowbytes - 1;
-            dp = row + ((png_size_t)row_width << 2) - 1;
+            dp = row + (png_size_t)(row_width << 2) - 1;
            for (i = 0; i < row_width; i++)
            {
               if (*(sp - 2) == red && *(sp - 1) == green && *(sp) == blue)
@@ -4542,7 +4537,7 @@ png_do_expand(png_row_infop row_info, png_bytep row,
            png_byte green_low = (png_byte)(trans_color->green & 0xff);
            png_byte blue_low = (png_byte)(trans_color->blue & 0xff);
            sp = row + row_info->rowbytes - 1;
-            dp = row + ((png_size_t)row_width << 3) - 1;
+            dp = row + (png_size_t)(row_width << 3) - 1;
            for (i = 0; i < row_width; i++)
            {
               if (*(sp - 5) == red_high &&
@@ -4601,9 +4596,7 @@ png_do_expand_16(png_row_infop row_info, png_bytep row)
      png_byte *sp = row + row_info->rowbytes; /* source, last byte + 1 */
      png_byte *dp = sp + row_info->rowbytes;  /* destination, end + 1 */
      while (dp > sp)
-      {
-         dp[-2] = dp[-1] = *--sp; dp -= 2;
-      }
+         dp[-2] = dp[-1] = *--sp, dp -= 2;

      row_info->rowbytes *= 2;
      row_info->bit_depth = 16;
--- a/pngrutil.c
+++ b/pngrutil.c
@@ -1,8 +1,8 @@

 /* pngrutil.c - utilities to read a PNG file
 *
- * Last changed in libpng 1.6.30 [(PENDING RELEASE)]
- * Copyright (c) 1998-2002,2004,2006-2017 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.25 [(PENDING RELEASE)]
+ * Copyright (c) 1998-2002,2004,2006-2016 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.)
 *
@@ -86,7 +86,7 @@ png_get_int_32)(png_const_bytep buf)
 {
   png_uint_32 uval = png_get_uint_32(buf);
   if ((uval & 0x80000000) == 0) /* non-negative */
-      return (png_int_32)uval;
+      return uval;

   uval = (uval ^ 0xffffffff) + 1;  /* 2's complement: -x = ~x+1 */
   if ((uval & 0x80000000) == 0) /* no overflow */
@@ -370,10 +370,11 @@ png_inflate_claim(png_structrp png_ptr, png_uint_32 owner)
    */
   {
      int ret; /* zlib return code */
-#if ZLIB_VERNUM >= 0x1240
-      int window_bits = 0;
+#if PNG_ZLIB_VERNUM >= 0x1240

 # if defined(PNG_SET_OPTION_SUPPORTED) && defined(PNG_MAXIMUM_INFLATE_WINDOW)
+      int window_bits;
+
      if (((png_ptr->options >> PNG_MAXIMUM_INFLATE_WINDOW) & 3) ==
          PNG_OPTION_ON)
      {
@@ -383,11 +384,13 @@ png_inflate_claim(png_structrp png_ptr, png_uint_32 owner)

      else
      {
+         window_bits = 0;
         png_ptr->zstream_start = 1;
      }
+# else
+#   define window_bits 0
 # endif
-
-#endif /* ZLIB_VERNUM >= 0x1240 */
+#endif

      /* Set this for safety, just in case the previous owner left pointers to
       * memory allocations.
@@ -399,32 +402,25 @@ png_inflate_claim(png_structrp png_ptr, png_uint_32 owner)

      if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
      {
-#if ZLIB_VERNUM >= 0x1240
-         ret = inflateReset2(&png_ptr->zstream, window_bits);
-#else
+#if PNG_ZLIB_VERNUM < 0x1240
         ret = inflateReset(&png_ptr->zstream);
+#else
+         ret = inflateReset2(&png_ptr->zstream, window_bits);
 #endif
      }

      else
      {
-#if ZLIB_VERNUM >= 0x1240
-         ret = inflateInit2(&png_ptr->zstream, window_bits);
-#else
+#if PNG_ZLIB_VERNUM < 0x1240
         ret = inflateInit(&png_ptr->zstream);
+#else
+         ret = inflateInit2(&png_ptr->zstream, window_bits);
 #endif

         if (ret == Z_OK)
            png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED;
      }

-#if ZLIB_VERNUM >= 0x1290 && \
-   defined(PNG_SET_OPTION_SUPPORTED) && defined(PNG_IGNORE_ADLER32)
-      if (((png_ptr->options >> PNG_IGNORE_ADLER32) & 3) == PNG_OPTION_ON)
-         /* Turn off validation of the ADLER32 checksum in IDAT chunks */
-         ret = inflateValidate(&png_ptr->zstream, 0);
-#endif
-
      if (ret == Z_OK)
         png_ptr->zowner = owner;

@@ -439,7 +435,7 @@ png_inflate_claim(png_structrp png_ptr, png_uint_32 owner)
 #endif
 }

-#if ZLIB_VERNUM >= 0x1240
+#if PNG_ZLIB_VERNUM >= 0x1240
 /* Handle the start of the inflate stream if we called inflateInit2(strm,0);
 * in this case some zlib versions skip validation of the CINFO field and, in
 * certain circumstances, libpng may end up displaying an invalid image, in
@@ -717,7 +713,7 @@ png_decompress_chunk(png_structrp png_ptr,
                   * the extra space may otherwise be used as a Trojan Horse.
                   */
                  if (ret == Z_STREAM_END &&
-                      chunklength - prefix_size != lzsize)
+                     chunklength - prefix_size != lzsize)
                     png_chunk_benign_error(png_ptr, "extra compressed data");
               }

@@ -827,7 +823,7 @@ png_inflate_read(png_structrp png_ptr, png_bytep read_buffer, uInt read_size,
      return Z_STREAM_ERROR;
   }
 }
-#endif /* READ_iCCP */
+#endif

 /* Read and check the IDHR chunk */

@@ -1015,7 +1011,7 @@ png_handle_PLTE(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
 #endif
   {
-      png_crc_finish(png_ptr, (png_uint_32) (length - (unsigned int)num * 3));
+      png_crc_finish(png_ptr, (int) length - num * 3);
   }

 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
@@ -1721,13 +1717,13 @@ png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
   data_length = length - (png_uint_32)(entry_start - buffer);

   /* Integrity-check the data length */
-   if ((data_length % (unsigned int)entry_size) != 0)
+   if ((data_length % entry_size) != 0)
   {
      png_warning(png_ptr, "sPLT chunk has bad length");
      return;
   }

-   dl = (png_uint_32)(data_length / (unsigned int)entry_size);
+   dl = (png_int_32)(data_length / entry_size);
   max_dl = PNG_SIZE_MAX / (sizeof (png_sPLT_entry));

   if (dl > max_dl)
@@ -1736,10 +1732,10 @@ png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
      return;
   }

-   new_palette.nentries = (png_int_32)(data_length / (unsigned int)entry_size);
+   new_palette.nentries = (png_int_32)(data_length / entry_size);

-   new_palette.entries = (png_sPLT_entryp)png_malloc_warn(png_ptr,
-       (png_alloc_size_t) new_palette.nentries * (sizeof (png_sPLT_entry)));
+   new_palette.entries = (png_sPLT_entryp)png_malloc_warn(
+       png_ptr, new_palette.nentries * (sizeof (png_sPLT_entry)));

   if (new_palette.entries == NULL)
   {
@@ -3103,7 +3099,7 @@ png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display)
 #     ifdef PNG_READ_PACKSWAP_SUPPORTED
      if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
         /* little-endian byte */
-         end_mask = (unsigned int)(0xff << end_mask);
+         end_mask = 0xff << end_mask;

      else /* big-endian byte */
 #     endif
@@ -3377,7 +3373,7 @@ png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display)
                */
               do
               {
-                  dp[0] = sp[0]; dp[1] = sp[1];
+                  dp[0] = sp[0], dp[1] = sp[1];

                  if (row_width <= bytes_to_jump)
                     return;
@@ -3398,7 +3394,7 @@ png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display)
                */
               for (;;)
               {
-                  dp[0] = sp[0]; dp[1] = sp[1]; dp[2] = sp[2];
+                  dp[0] = sp[0], dp[1] = sp[1], dp[2] = sp[2];

                  if (row_width <= bytes_to_jump)
                     return;
@@ -3549,7 +3545,7 @@ png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
 {
   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
   /* Offset to next interlace block */
-   static PNG_CONST unsigned int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+   static PNG_CONST int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};

   png_debug(1, "in png_do_read_interlace");
   if (row != NULL && row_info != NULL)
@@ -3564,10 +3560,9 @@ png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
         {
            png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 3);
            png_bytep dp = row + (png_size_t)((final_width - 1) >> 3);
-            unsigned int sshift, dshift;
-            unsigned int s_start, s_end;
-            int s_inc;
-            int jstop = (int)png_pass_inc[pass];
+            int sshift, dshift;
+            int s_start, s_end, s_inc;
+            int jstop = png_pass_inc[pass];
            png_byte v;
            png_uint_32 i;
            int j;
@@ -3575,8 +3570,8 @@ png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
 #ifdef PNG_READ_PACKSWAP_SUPPORTED
            if ((transformations & PNG_PACKSWAP) != 0)
            {
-                sshift = ((row_info->width + 7) & 0x07);
-                dshift = ((final_width + 7) & 0x07);
+                sshift = (int)((row_info->width + 7) & 0x07);
+                dshift = (int)((final_width + 7) & 0x07);
                s_start = 7;
                s_end = 0;
                s_inc = -1;
@@ -3585,8 +3580,8 @@ png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
            else
 #endif
            {
-                sshift = 7 - ((row_info->width + 7) & 0x07);
-                dshift = 7 - ((final_width + 7) & 0x07);
+                sshift = 7 - (int)((row_info->width + 7) & 0x07);
+                dshift = 7 - (int)((final_width + 7) & 0x07);
                s_start = 0;
                s_end = 7;
                s_inc = 1;
@@ -3598,7 +3593,7 @@ png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
               for (j = 0; j < jstop; j++)
               {
                  unsigned int tmp = *dp & (0x7f7f >> (7 - dshift));
-                  tmp |= (unsigned int)(v << dshift);
+                  tmp |= v << dshift;
                  *dp = (png_byte)(tmp & 0xff);

                  if (dshift == s_end)
@@ -3608,7 +3603,7 @@ png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
                  }

                  else
-                     dshift = (unsigned int)((int)dshift + s_inc);
+                     dshift += s_inc;
               }

               if (sshift == s_end)
@@ -3618,7 +3613,7 @@ png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
               }

               else
-                  sshift = (unsigned int)((int)sshift + s_inc);
+                  sshift += s_inc;
            }
            break;
         }
@@ -3627,17 +3622,16 @@ png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
         {
            png_bytep sp = row + (png_uint_32)((row_info->width - 1) >> 2);
            png_bytep dp = row + (png_uint_32)((final_width - 1) >> 2);
-            unsigned int sshift, dshift;
-            unsigned int s_start, s_end;
-            int s_inc;
-            int jstop = (int)png_pass_inc[pass];
+            int sshift, dshift;
+            int s_start, s_end, s_inc;
+            int jstop = png_pass_inc[pass];
            png_uint_32 i;

 #ifdef PNG_READ_PACKSWAP_SUPPORTED
            if ((transformations & PNG_PACKSWAP) != 0)
            {
-               sshift = (((row_info->width + 3) & 0x03) << 1);
-               dshift = (((final_width + 3) & 0x03) << 1);
+               sshift = (int)(((row_info->width + 3) & 0x03) << 1);
+               dshift = (int)(((final_width + 3) & 0x03) << 1);
               s_start = 6;
               s_end = 0;
               s_inc = -2;
@@ -3646,8 +3640,8 @@ png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
            else
 #endif
            {
-               sshift = ((3 - ((row_info->width + 3) & 0x03)) << 1);
-               dshift = ((3 - ((final_width + 3) & 0x03)) << 1);
+               sshift = (int)((3 - ((row_info->width + 3) & 0x03)) << 1);
+               dshift = (int)((3 - ((final_width + 3) & 0x03)) << 1);
               s_start = 0;
               s_end = 6;
               s_inc = 2;
@@ -3662,7 +3656,7 @@ png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
               for (j = 0; j < jstop; j++)
               {
                  unsigned int tmp = *dp & (0x3f3f >> (6 - dshift));
-                  tmp |= (unsigned int)(v << dshift);
+                  tmp |= v << dshift;
                  *dp = (png_byte)(tmp & 0xff);

                  if (dshift == s_end)
@@ -3672,7 +3666,7 @@ png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
                  }

                  else
-                     dshift = (unsigned int)((int)dshift + s_inc);
+                     dshift += s_inc;
               }

               if (sshift == s_end)
@@ -3682,7 +3676,7 @@ png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
               }

               else
-                  sshift = (unsigned int)((int)sshift + s_inc);
+                  sshift += s_inc;
            }
            break;
         }
@@ -3691,17 +3685,16 @@ png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
         {
            png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 1);
            png_bytep dp = row + (png_size_t)((final_width - 1) >> 1);
-            unsigned int sshift, dshift;
-            unsigned int s_start, s_end;
-            int s_inc;
+            int sshift, dshift;
+            int s_start, s_end, s_inc;
            png_uint_32 i;
-            int jstop = (int)png_pass_inc[pass];
+            int jstop = png_pass_inc[pass];

 #ifdef PNG_READ_PACKSWAP_SUPPORTED
            if ((transformations & PNG_PACKSWAP) != 0)
            {
-               sshift = (((row_info->width + 1) & 0x01) << 2);
-               dshift = (((final_width + 1) & 0x01) << 2);
+               sshift = (int)(((row_info->width + 1) & 0x01) << 2);
+               dshift = (int)(((final_width + 1) & 0x01) << 2);
               s_start = 4;
               s_end = 0;
               s_inc = -4;
@@ -3710,8 +3703,8 @@ png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
            else
 #endif
            {
-               sshift = ((1 - ((row_info->width + 1) & 0x01)) << 2);
-               dshift = ((1 - ((final_width + 1) & 0x01)) << 2);
+               sshift = (int)((1 - ((row_info->width + 1) & 0x01)) << 2);
+               dshift = (int)((1 - ((final_width + 1) & 0x01)) << 2);
               s_start = 0;
               s_end = 4;
               s_inc = 4;
@@ -3725,7 +3718,7 @@ png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
               for (j = 0; j < jstop; j++)
               {
                  unsigned int tmp = *dp & (0xf0f >> (4 - dshift));
-                  tmp |= (unsigned int)(v << dshift);
+                  tmp |= v << dshift;
                  *dp = (png_byte)(tmp & 0xff);

                  if (dshift == s_end)
@@ -3735,7 +3728,7 @@ png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
                  }

                  else
-                     dshift = (unsigned int)((int)dshift + s_inc);
+                     dshift += s_inc;
               }

               if (sshift == s_end)
@@ -3745,7 +3738,7 @@ png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
               }

               else
-                  sshift = (unsigned int)((int)sshift + s_inc);
+                  sshift += s_inc;
            }
            break;
         }
@@ -3759,7 +3752,7 @@ png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,

            png_bytep dp = row + (png_size_t)(final_width - 1) * pixel_bytes;

-            int jstop = (int)png_pass_inc[pass];
+            int jstop = png_pass_inc[pass];
            png_uint_32 i;

            for (i = 0; i < row_info->width; i++)
@@ -3887,10 +3880,7 @@ png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info, png_bytep row,
      /* Find the best predictor, the least of pa, pb, pc favoring the earlier
       * ones in the case of a tie.
       */
-      if (pb < pa)
-      {
-         pa = pb; a = b;
-      }
+      if (pb < pa) pa = pb, a = b;
      if (pc < pa) a = c;

      /* Calculate the current pixel in a, and move the previous row pixel to c
@@ -3906,7 +3896,7 @@ static void
 png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row,
    png_const_bytep prev_row)
 {
-   unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
+   int bpp = (row_info->pixel_depth + 7) >> 3;
   png_bytep rp_end = row + bpp;

   /* Process the first pixel in the row completely (this is the same as 'up'
@@ -3919,7 +3909,7 @@ png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row,
   }

   /* Remainder */
-   rp_end = rp_end + (row_info->rowbytes - bpp);
+   rp_end += row_info->rowbytes - bpp;

   while (row < rp_end)
   {
@@ -3942,10 +3932,7 @@ png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row,
      pc = (p + pc) < 0 ? -(p + pc) : p + pc;
 #endif

-      if (pb < pa)
-      {
-         pa = pb; a = b;
-      }
+      if (pb < pa) pa = pb, a = b;
      if (pc < pa) a = c;

      a += *row;
@@ -4267,7 +4254,7 @@ png_read_start_row(png_structrp png_ptr)
   /* Offset to next interlace block in the y direction */
   static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};

-   unsigned int max_pixel_depth;
+   int max_pixel_depth;
   png_size_t row_bytes;

   png_debug(1, "in png_read_start_row");
@@ -4296,7 +4283,7 @@ png_read_start_row(png_structrp png_ptr)
      png_ptr->iwidth = png_ptr->width;
   }

-   max_pixel_depth = (unsigned int)png_ptr->pixel_depth;
+   max_pixel_depth = png_ptr->pixel_depth;

   /* WARNING: * png_read_transform_info (pngrtran.c) performs a simpler set of
    * calculations to calculate the final pixel depth, then
@@ -4431,7 +4418,7 @@ png_read_start_row(png_structrp png_ptr)
 defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
   if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
   {
-      unsigned int user_pixel_depth = png_ptr->user_transform_depth *
+      int user_pixel_depth = png_ptr->user_transform_depth *
         png_ptr->user_transform_channels;

      if (user_pixel_depth > max_pixel_depth)
@@ -4453,7 +4440,7 @@ defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
    * for safety's sake
    */
   row_bytes = PNG_ROWBYTES(max_pixel_depth, row_bytes) +
-       1 + ((max_pixel_depth + 7) >> 3U);
+       1 + ((max_pixel_depth + 7) >> 3);

 #ifdef PNG_MAX_MALLOC_64K
   if (row_bytes > (png_uint_32)65536L)
@@ -4522,7 +4509,7 @@ defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
    * does not, so free the read buffer now regardless; the sequential reader
    * reallocates it on demand.
    */
-   if (png_ptr->read_buffer != NULL)
+   if (png_ptr->read_buffer != 0)
   {
      png_bytep buffer = png_ptr->read_buffer;

--- a/pngset.c
+++ b/pngset.c
@@ -1,8 +1,8 @@

 /* pngset.c - storage of image information into info struct
 *
- * Last changed in libpng 1.6.30 [(PENDING RELEASE)]
- * Copyright (c) 1998-2017 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.24 [August 4, 2016]
+ * Copyright (c) 1998-2016 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
@@ -283,29 +283,17 @@ png_set_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,

   /* Check that the type matches the specification. */
   if (type < 0 || type > 3)
-   {
-      png_chunk_report(png_ptr, "Invalid pCAL equation type",
-            PNG_CHUNK_WRITE_ERROR);
-      return;
-   }
+      png_error(png_ptr, "Invalid pCAL equation type");

   if (nparams < 0 || nparams > 255)
-   {
-      png_chunk_report(png_ptr, "Invalid pCAL parameter count",
-            PNG_CHUNK_WRITE_ERROR);
-      return;
-   }
+      png_error(png_ptr, "Invalid pCAL parameter count");

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

   info_ptr->pcal_purpose = png_voidcast(png_charp,
@@ -313,8 +301,8 @@ png_set_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,

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

@@ -343,7 +331,7 @@ png_set_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,
   memcpy(info_ptr->pcal_units, units, length);

   info_ptr->pcal_params = png_voidcast(png_charpp, png_malloc_warn(png_ptr,
-       (png_size_t)(((unsigned int)nparams + 1) * (sizeof (png_charp)))));
+       (png_size_t)((nparams + 1) * (sizeof (png_charp)))));

   if (info_ptr->pcal_params == NULL)
   {
@@ -352,8 +340,7 @@ png_set_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,
      return;
   }

-   memset(info_ptr->pcal_params, 0, ((unsigned int)nparams + 1) *
-       (sizeof (png_charp)));
+   memset(info_ptr->pcal_params, 0, (nparams + 1) * (sizeof (png_charp)));

   for (i = 0; i < nparams; i++)
   {
@@ -576,8 +563,7 @@ png_set_PLTE(png_structrp png_ptr, png_inforp info_ptr,
       PNG_MAX_PALETTE_LENGTH * (sizeof (png_color))));

   if (num_palette > 0)
-      memcpy(png_ptr->palette, palette, (unsigned int)num_palette *
-          (sizeof (png_color)));
+      memcpy(png_ptr->palette, palette, num_palette * (sizeof (png_color)));
   info_ptr->palette = png_ptr->palette;
   info_ptr->num_palette = png_ptr->num_palette = (png_uint_16)num_palette;

@@ -1094,7 +1080,7 @@ png_set_sPLT(png_const_structrp png_ptr,
       * checked it when doing the allocation.
       */
      memcpy(np->entries, entries->entries,
-          (unsigned int)entries->nentries * sizeof (png_sPLT_entry));
+          entries->nentries * sizeof (png_sPLT_entry));

      /* Note that 'continue' skips the advance of the out pointer and out
       * count, so an invalid entry is not added.
@@ -1102,9 +1088,8 @@ png_set_sPLT(png_const_structrp png_ptr,
      info_ptr->valid |= PNG_INFO_sPLT;
      ++(info_ptr->splt_palettes_num);
      ++np;
-      ++entries;
   }
-   while (--nentries);
+   while (++entries, --nentries);

   if (nentries > 0)
      png_chunk_report(png_ptr, "sPLT out of memory", PNG_CHUNK_WRITE_ERROR);
@@ -1264,7 +1249,7 @@ png_set_unknown_chunk_location(png_const_structrp png_ptr, png_inforp info_ptr,
      {
         png_app_error(png_ptr, "invalid unknown chunk location");
         /* Fake out the pre 1.6.0 behavior: */
-         if (((unsigned int)location & PNG_HAVE_IDAT) != 0) /* undocumented! */
+         if ((location & PNG_HAVE_IDAT) != 0) /* undocumented! */
            location = PNG_AFTER_IDAT;

         else
@@ -1388,7 +1373,7 @@ png_set_keep_unknown_chunks(png_structrp png_ptr, int keep,
         return;
      }

-      num_chunks = (unsigned int)num_chunks_in;
+      num_chunks = num_chunks_in;
   }

   old_num_chunks = png_ptr->num_chunk_list;
@@ -1578,7 +1563,7 @@ void PNGAPI
 png_set_invalid(png_const_structrp png_ptr, png_inforp info_ptr, int mask)
 {
   if (png_ptr != NULL && info_ptr != NULL)
-      info_ptr->valid &= (unsigned int)(~mask);
+      info_ptr->valid &= ~mask;
 }


@@ -1697,16 +1682,14 @@ png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key)
      png_byte ch = (png_byte)*key++;

      if ((ch > 32 && ch <= 126) || (ch >= 161 /*&& ch <= 255*/))
-      {
-         *new_key++ = ch; ++key_len; space = 0;
-      }
+         *new_key++ = ch, ++key_len, space = 0;

      else if (space == 0)
      {
         /* A space or an invalid character when one wasn't seen immediately
          * before; output just a space.
          */
-         *new_key++ = 32; ++key_len; space = 1;
+         *new_key++ = 32, ++key_len, space = 1;

         /* If the character was not a space then it is invalid. */
         if (ch != 32)
@@ -1719,7 +1702,7 @@ png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key)

   if (key_len > 0 && space != 0) /* trailing space */
   {
-      --key_len; --new_key;
+      --key_len, --new_key;
      if (bad_character == 0)
         bad_character = 32;
   }
--- a/pngstruct.h
+++ b/pngstruct.h
@@ -1,8 +1,8 @@

 /* pngstruct.h - header file for PNG reference library
 *
- * Last changed in libpng 1.6.28 [January 5, 2017]
- * Copyright (c) 1998-2002,2004,2006-2017 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.24 [August 4, 2016]
+ * Copyright (c) 1998-2002,2004,2006-2016 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.)
 *
@@ -263,7 +263,7 @@ struct png_struct_def
                              /* pixel depth used for the row buffers */
   png_byte transformed_pixel_depth;
                              /* pixel depth after read/write transforms */
-#if ZLIB_VERNUM >= 0x1240
+#if PNG_ZLIB_VERNUM >= 0x1240
   png_byte zstream_start;    /* at start of an input zlib stream */
 #endif /* Zlib >= 1.2.4 */
 #if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
@@ -353,7 +353,7 @@ struct png_struct_def

 /* Options */
 #ifdef PNG_SET_OPTION_SUPPORTED
-   png_uint_32 options;           /* On/off state (up to 16 options) */
+   png_byte options;           /* On/off state (up to 4 options) */
 #endif

 #if PNG_LIBPNG_VER < 10700
--- a/pngtest.c
+++ b/pngtest.c
@@ -1,7 +1,7 @@

 /* pngtest.c - a simple test program to test libpng
 *
- * Last changed in libpng 1.6.26 [October 20, 2016]
+ * Last changed in libpng 1.6.25 [(PENDING RELEASE)]
 * Copyright (c) 1998-2002,2004,2006-2016 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.)
@@ -43,6 +43,15 @@

 #include "png.h"

+/* 1.6.1 added support for the configure test harness, which uses 77 to indicate
+ * a skipped test, in earlier versions we need to succeed on a skipped test, so:
+ */
+#if PNG_LIBPNG_VER >= 10601 && defined(HAVE_CONFIG_H)
+#  define SKIP 77
+#else
+#  define SKIP 0
+#endif
+
 /* Known chunks that exist in pngtest.png must be supported or pngtest will fail
 * simply as a result of re-ordering them.  This may be fixed in 1.7
 *
@@ -505,10 +514,10 @@ typedef struct memory_information
 typedef memory_information *memory_infop;

 static memory_infop pinformation = NULL;
-static int current_allocation = 0;
-static int maximum_allocation = 0;
-static int total_allocation = 0;
-static int num_allocations = 0;
+static png_alloc_size_t current_allocation = 0;
+static png_alloc_size_t maximum_allocation = 0;
+static png_alloc_size_t total_allocation = 0;
+static png_alloc_size_t num_allocations = 0;

 png_voidp PNGCBAPI png_debug_malloc PNGARG((png_structp png_ptr,
    png_alloc_size_t size));
@@ -595,9 +604,10 @@ png_debug_free(png_structp png_ptr, png_voidp ptr)
         if (pinfo->pointer == ptr)
         {
            *ppinfo = pinfo->next;
-            current_allocation -= pinfo->size;
-            if (current_allocation < 0)
+            if (current_allocation < pinfo->size)
               fprintf(STDERR, "Duplicate free of memory\n");
+            else
+               current_allocation -= pinfo->size;
            /* We must free the list element too, but first kill
               the memory that is to be freed. */
            memset(ptr, 0x55, pinfo->size);
@@ -929,6 +939,12 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
       read_user_chunk_callback);
 #endif

+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+#  ifdef CHUNK_LIMIT /* from the build, for testing */
+      png_set_chunk_malloc_max(read_ptr, CHUNK_LIMIT);
+#  endif /* CHUNK_LIMIT */
+#endif
+
 #ifdef PNG_SETJMP_SUPPORTED
   pngtest_debug("Setting jmpbuf for read struct");
   if (setjmp(png_jmpbuf(read_ptr)))
@@ -964,16 +980,15 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
 #endif
 #endif

-#ifdef PNG_BENIGN_ERRORS_SUPPORTED
   if (strict != 0)
   {
      /* Treat png_benign_error() as errors on read */
      png_set_benign_errors(read_ptr, 0);

-# ifdef PNG_WRITE_SUPPORTED
+#ifdef PNG_WRITE_SUPPORTED
      /* Treat them as errors on write */
      png_set_benign_errors(write_ptr, 0);
-# endif
+#endif

      /* if strict is not set, then app warnings and errors are treated as
       * warnings in release builds, but not in unstable builds; this can be
@@ -986,20 +1001,10 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      /* Allow application (pngtest) errors and warnings to pass */
      png_set_benign_errors(read_ptr, 1);

-      /* Turn off CRC checking while reading */
-      png_set_crc_action(read_ptr, PNG_CRC_QUIET_USE, PNG_CRC_QUIET_USE);
-
-#ifdef PNG_IGNORE_ADLER32
-      /* Turn off ADLER32 checking while reading */
-      png_set_option(read_ptr, PNG_IGNORE_ADLER32, PNG_OPTION_ON);
-#endif
-
-# ifdef PNG_WRITE_SUPPORTED
+#ifdef PNG_WRITE_SUPPORTED
      png_set_benign_errors(write_ptr, 1);
-# endif
-
+#endif
   }
-#endif /* BENIGN_ERRORS */

   pngtest_debug("Initializing input and output streams");
 #ifdef PNG_STDIO_SUPPORTED
@@ -1397,11 +1402,6 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
   png_write_info(write_ptr, write_info_ptr);

   write_chunks(write_ptr, before_IDAT); /* after PLTE */
-
-#ifdef PNG_COMPRESSION_COMPAT
-   /* Test the 'compatibility' setting here, if it is available. */
-   png_set_compression(write_ptr, PNG_COMPRESSION_COMPAT);
-#endif
 #endif

 #ifdef SINGLE_ROWBUF_ALLOC
@@ -1883,7 +1883,7 @@ main(int argc, char *argv[])
   {
      int i;
 #if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
-      int allocation_now = current_allocation;
+      png_alloc_size_t allocation_now = current_allocation;
 #endif
      for (i=2; i<argc; ++i)
      {
@@ -1916,15 +1916,15 @@ main(int argc, char *argv[])
         }
 #if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
         if (allocation_now != current_allocation)
-            fprintf(STDERR, "MEMORY ERROR: %d bytes lost\n",
-                current_allocation - allocation_now);
+            fprintf(STDERR, "MEMORY ERROR: %lu bytes lost\n",
+                (unsigned long)(current_allocation - allocation_now));

         if (current_allocation != 0)
         {
            memory_infop pinfo = pinformation;

-            fprintf(STDERR, "MEMORY ERROR: %d bytes still allocated\n",
-                current_allocation);
+            fprintf(STDERR, "MEMORY ERROR: %lu bytes still allocated\n",
+                (unsigned long)current_allocation);

            while (pinfo != NULL)
            {
@@ -1937,14 +1937,14 @@ main(int argc, char *argv[])
 #endif
      }
 #if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
-         fprintf(STDERR, " Current memory allocation: %10d bytes\n",
-             current_allocation);
-         fprintf(STDERR, " Maximum memory allocation: %10d bytes\n",
-             maximum_allocation);
-         fprintf(STDERR, " Total   memory allocation: %10d bytes\n",
-             total_allocation);
-         fprintf(STDERR, "     Number of allocations: %10d\n",
-             num_allocations);
+         fprintf(STDERR, " Current memory allocation: %20lu bytes\n",
+             (unsigned long)current_allocation);
+         fprintf(STDERR, " Maximum memory allocation: %20lu bytes\n",
+             (unsigned long) maximum_allocation);
+         fprintf(STDERR, " Total   memory allocation: %20lu bytes\n",
+             (unsigned long)total_allocation);
+         fprintf(STDERR, "     Number of allocations: %20lu\n",
+             (unsigned long)num_allocations);
 #endif
   }

@@ -1955,7 +1955,7 @@ main(int argc, char *argv[])
      {
         int kerror;
 #if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
-         int allocation_now = current_allocation;
+         png_alloc_size_t allocation_now = current_allocation;
 #endif
         if (i == 1)
            status_dots_requested = 1;
@@ -2005,15 +2005,15 @@ main(int argc, char *argv[])
         }
 #if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
         if (allocation_now != current_allocation)
-             fprintf(STDERR, "MEMORY ERROR: %d bytes lost\n",
-                 current_allocation - allocation_now);
+             fprintf(STDERR, "MEMORY ERROR: %lu bytes lost\n",
+                 (unsigned long)(current_allocation - allocation_now));

         if (current_allocation != 0)
         {
             memory_infop pinfo = pinformation;

-             fprintf(STDERR, "MEMORY ERROR: %d bytes still allocated\n",
-                 current_allocation);
+             fprintf(STDERR, "MEMORY ERROR: %lu bytes still allocated\n",
+                 (unsigned long)current_allocation);

             while (pinfo != NULL)
             {
@@ -2025,14 +2025,14 @@ main(int argc, char *argv[])
 #endif
       }
 #if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
-       fprintf(STDERR, " Current memory allocation: %10d bytes\n",
-           current_allocation);
-       fprintf(STDERR, " Maximum memory allocation: %10d bytes\n",
-           maximum_allocation);
-       fprintf(STDERR, " Total   memory allocation: %10d bytes\n",
-           total_allocation);
-       fprintf(STDERR, "     Number of allocations: %10d\n",
-           num_allocations);
+       fprintf(STDERR, " Current memory allocation: %20lu bytes\n",
+           (unsigned long)current_allocation);
+       fprintf(STDERR, " Maximum memory allocation: %20lu bytes\n",
+           (unsigned long)maximum_allocation);
+       fprintf(STDERR, " Total   memory allocation: %20lu bytes\n",
+           (unsigned long)total_allocation);
+       fprintf(STDERR, "     Number of allocations: %20lu\n",
+           (unsigned long)num_allocations);
 #endif
   }

@@ -2083,9 +2083,9 @@ main(void)
   fprintf(STDERR,
       " test ignored because libpng was not built with read support\n");
   /* And skip this test */
-   return PNG_LIBPNG_VER < 10600 ? 0 : 77;
+   return SKIP;
 }
 #endif

 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef png_libpng_version_1_6_30beta01 Your_png_h_is_not_version_1_6_30beta01;
+typedef png_libpng_version_1_6_25rc05 Your_png_h_is_not_version_1_6_25rc05;
--- a/pngtrans.c
+++ b/pngtrans.c
@@ -1,8 +1,8 @@

 /* pngtrans.c - transforms the data in a row (used by both readers and writers)
 *
- * Last changed in libpng 1.6.30 [(PENDING RELEASE)]
- * Copyright (c) 1998-2002,2004,2006-2017 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.24 [August 4, 2016]
+ * Copyright (c) 1998-2002,2004,2006-2016 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.)
 *
@@ -514,15 +514,11 @@ png_do_strip_channel(png_row_infop row_info, png_bytep row, int at_start)
         if (at_start != 0) /* Skip initial filler */
            ++sp;
         else          /* Skip initial channel and, for sp, the filler */
-         {
-            sp += 2; ++dp;
-         }
+            sp += 2, ++dp;

         /* For a 1 pixel wide image there is nothing to do */
         while (sp < ep)
-         {
-            *dp++ = *sp; sp += 2;
-         }
+            *dp++ = *sp, sp += 2;

         row_info->pixel_depth = 8;
      }
@@ -532,14 +528,10 @@ png_do_strip_channel(png_row_infop row_info, png_bytep row, int at_start)
         if (at_start != 0) /* Skip initial filler */
            sp += 2;
         else          /* Skip initial channel and, for sp, the filler */
-         {
-            sp += 4; dp += 2;
-         }
+            sp += 4, dp += 2;

         while (sp < ep)
-         {
-            *dp++ = *sp++; *dp++ = *sp; sp += 3;
-         }
+            *dp++ = *sp++, *dp++ = *sp, sp += 3;

         row_info->pixel_depth = 16;
      }
@@ -562,15 +554,11 @@ png_do_strip_channel(png_row_infop row_info, png_bytep row, int at_start)
         if (at_start != 0) /* Skip initial filler */
            ++sp;
         else          /* Skip initial channels and, for sp, the filler */
-         {
-            sp += 4; dp += 3;
-         }
+            sp += 4, dp += 3;

         /* Note that the loop adds 3 to dp and 4 to sp each time. */
         while (sp < ep)
-         {
-            *dp++ = *sp++; *dp++ = *sp++; *dp++ = *sp; sp += 2;
-         }
+            *dp++ = *sp++, *dp++ = *sp++, *dp++ = *sp, sp += 2;

         row_info->pixel_depth = 24;
      }
@@ -580,16 +568,14 @@ png_do_strip_channel(png_row_infop row_info, png_bytep row, int at_start)
         if (at_start != 0) /* Skip initial filler */
            sp += 2;
         else          /* Skip initial channels and, for sp, the filler */
-         {
-            sp += 8; dp += 6;
-         }
+            sp += 8, dp += 6;

         while (sp < ep)
         {
            /* Copy 6 bytes, skip 2 */
-            *dp++ = *sp++; *dp++ = *sp++;
-            *dp++ = *sp++; *dp++ = *sp++;
-            *dp++ = *sp++; *dp++ = *sp; sp += 3;
+            *dp++ = *sp++, *dp++ = *sp++;
+            *dp++ = *sp++, *dp++ = *sp++;
+            *dp++ = *sp++, *dp++ = *sp, sp += 3;
         }

         row_info->pixel_depth = 48;
@@ -609,7 +595,7 @@ png_do_strip_channel(png_row_infop row_info, png_bytep row, int at_start)
      return; /* The filler channel has gone already */

   /* Fix the rowbytes value. */
-   row_info->rowbytes = (unsigned int)(dp-row);
+   row_info->rowbytes = dp-row;
 }
 #endif

@@ -707,7 +693,7 @@ png_do_check_palette_indexes(png_structrp png_ptr, png_row_infop row_info)
       * and this calculation is used because it avoids warnings that other
       * forms produced on either GCC or MSVC.
       */
-      int padding = PNG_PADBITS(row_info->pixel_depth, row_info->width);
+      int padding = (-row_info->pixel_depth * row_info->width) & 7;
      png_bytep rp = png_ptr->row_buf + row_info->rowbytes;

      switch (row_info->bit_depth)
--- a/pngwrite.c
+++ b/pngwrite.c
@@ -1,7 +1,7 @@

 /* pngwrite.c - general routines to write a PNG file
 *
- * Last changed in libpng 1.6.26 [October 20, 2016]
+ * Last changed in libpng 1.6.24 [August 4, 2016]
 * Copyright (c) 1998-2002,2004,2006-2016 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.)
@@ -666,9 +666,9 @@ png_do_write_intrapixel(png_row_infop row_info, png_bytep row)

         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
         {
-            png_uint_32 s0   = (png_uint_32)(*(rp    ) << 8) | *(rp + 1);
-            png_uint_32 s1   = (png_uint_32)(*(rp + 2) << 8) | *(rp + 3);
-            png_uint_32 s2   = (png_uint_32)(*(rp + 4) << 8) | *(rp + 5);
+            png_uint_32 s0   = (*(rp    ) << 8) | *(rp + 1);
+            png_uint_32 s1   = (*(rp + 2) << 8) | *(rp + 3);
+            png_uint_32 s2   = (*(rp + 4) << 8) | *(rp + 5);
            png_uint_32 red  = (png_uint_32)((s0 - s1) & 0xffffL);
            png_uint_32 blue = (png_uint_32)((s2 - s1) & 0xffffL);
            *(rp    ) = (png_byte)(red >> 8);
@@ -901,7 +901,7 @@ png_set_flush(png_structrp png_ptr, int nrows)
   if (png_ptr == NULL)
      return;

-   png_ptr->flush_dist = (nrows < 0 ? 0 : (png_uint_32)nrows);
+   png_ptr->flush_dist = (nrows < 0 ? 0 : nrows);
 }

 /* Flush the current output buffers now */
@@ -1525,8 +1525,7 @@ png_write_image_16bit(png_voidp argument)
       display->first_row);
   png_uint_16p output_row = png_voidcast(png_uint_16p, display->local_row);
   png_uint_16p row_end;
-   const unsigned int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ?
-       3 : 1;
+   const int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ? 3 : 1;
   int aindex = 0;
   png_uint_32 y = image->height;

@@ -1540,9 +1539,9 @@ png_write_image_16bit(png_voidp argument)
         ++output_row;
      }
         else
-            aindex = (int)channels;
+            aindex = channels;
 #     else
-         aindex = (int)channels;
+         aindex = channels;
 #     endif
   }

@@ -1555,7 +1554,7 @@ png_write_image_16bit(png_voidp argument)
    */
   row_end = output_row + image->width * (channels+1);

-   for (; y > 0; --y)
+   while (y-- > 0)
   {
      png_const_uint_16p in_ptr = input_row;
      png_uint_16p out_ptr = output_row;
@@ -1576,7 +1575,7 @@ png_write_image_16bit(png_voidp argument)
         if (alpha > 0 && alpha < 65535)
            reciprocal = ((0xffff<<15)+(alpha>>1))/alpha;

-         c = (int)channels;
+         c = channels;
         do /* always at least one channel */
         {
            png_uint_16 component = *in_ptr++;
@@ -1611,7 +1610,7 @@ png_write_image_16bit(png_voidp argument)
      }

      png_write_row(png_ptr, png_voidcast(png_const_bytep, display->local_row));
-      input_row += (png_uint_16)display->row_bytes/(sizeof (png_uint_16));
+      input_row += display->row_bytes/(sizeof (png_uint_16));
   }

   return 1;
@@ -1684,8 +1683,7 @@ png_write_image_8bit(png_voidp argument)
       display->first_row);
   png_bytep output_row = png_voidcast(png_bytep, display->local_row);
   png_uint_32 y = image->height;
-   const unsigned int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ?
-       3 : 1;
+   const int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ? 3 : 1;

   if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
   {
@@ -1702,12 +1700,12 @@ png_write_image_8bit(png_voidp argument)

      else
 #   endif
-      aindex = (int)channels;
+      aindex = channels;

      /* Use row_end in place of a loop counter: */
      row_end = output_row + image->width * (channels+1);

-      for (; y > 0; --y)
+      while (y-- > 0)
      {
         png_const_uint_16p in_ptr = input_row;
         png_bytep out_ptr = output_row;
@@ -1725,7 +1723,7 @@ png_write_image_8bit(png_voidp argument)
            if (alphabyte > 0 && alphabyte < 255)
               reciprocal = UNP_RECIPROCAL(alpha);

-            c = (int)channels;
+            c = channels;
            do /* always at least one channel */
               *out_ptr++ = png_unpremultiply(*in_ptr++, alpha, reciprocal);
            while (--c > 0);
@@ -1737,7 +1735,7 @@ png_write_image_8bit(png_voidp argument)

         png_write_row(png_ptr, png_voidcast(png_const_bytep,
             display->local_row));
-         input_row += (png_uint_16)display->row_bytes/(sizeof (png_uint_16));
+         input_row += display->row_bytes/(sizeof (png_uint_16));
      } /* while y */
   }

@@ -1748,7 +1746,7 @@ png_write_image_8bit(png_voidp argument)
       */
      png_bytep row_end = output_row + image->width * channels;

-      for (; y > 0; --y)
+      while (y-- > 0)
      {
         png_const_uint_16p in_ptr = input_row;
         png_bytep out_ptr = output_row;
@@ -1762,7 +1760,7 @@ png_write_image_8bit(png_voidp argument)
         }

         png_write_row(png_ptr, output_row);
-         input_row += (png_uint_16)display->row_bytes/(sizeof (png_uint_16));
+         input_row += display->row_bytes/(sizeof (png_uint_16));
      }
   }

@@ -1779,7 +1777,7 @@ png_image_set_PLTE(png_image_write_control *display)

   /* NOTE: the caller must check for cmap != NULL and entries != 0 */
   const png_uint_32 format = image->format;
-   const unsigned int channels = PNG_IMAGE_SAMPLE_CHANNELS(format);
+   const int channels = PNG_IMAGE_SAMPLE_CHANNELS(format);

 #   if defined(PNG_FORMAT_BGR_SUPPORTED) &&\
      defined(PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED)
@@ -1811,7 +1809,7 @@ png_image_set_PLTE(png_image_write_control *display)
      {
         png_const_uint_16p entry = png_voidcast(png_const_uint_16p, cmap);

-         entry += (unsigned int)i * channels;
+         entry += i * channels;

         if ((channels & 1) != 0) /* no alpha */
         {
@@ -1867,7 +1865,7 @@ png_image_set_PLTE(png_image_write_control *display)
      {
         png_const_bytep entry = png_voidcast(png_const_bytep, cmap);

-         entry += (unsigned int)i * channels;
+         entry += i * channels;

         switch (channels)
         {
@@ -1912,7 +1910,7 @@ png_image_set_PLTE(png_image_write_control *display)
      png_set_tRNS(image->opaque->png_ptr, image->opaque->info_ptr, tRNS,
          num_trans, NULL);

-   image->colormap_entries = (png_uint_32)entries;
+   image->colormap_entries = entries;
 }

 static int
@@ -1942,7 +1940,7 @@ png_image_write_main(png_voidp argument)
   {
      const unsigned int channels = PNG_IMAGE_PIXEL_CHANNELS(image->format);

-      if (image->width <= 0x7fffffffU/channels) /* no overflow */
+      if (image->width <= 0x7FFFFFFFU/channels) /* no overflow */
      {
         png_uint_32 check;
         const png_uint_32 png_row_stride = image->width * channels;
@@ -1951,10 +1949,10 @@ png_image_write_main(png_voidp argument)
            display->row_stride = (png_int_32)/*SAFE*/png_row_stride;

         if (display->row_stride < 0)
-            check = (png_uint_32)(-display->row_stride);
+            check = -display->row_stride;

         else
-            check = (png_uint_32)display->row_stride;
+            check = display->row_stride;

         if (check >= png_row_stride)
         {
@@ -1962,7 +1960,7 @@ png_image_write_main(png_voidp argument)
             * limits the whole image size to 32 bits for API compatibility with
             * the current, 32-bit, PNG_IMAGE_BUFFER_SIZE macro.
             */
-            if (image->height > 0xffffffffU/png_row_stride)
+            if (image->height > 0xFFFFFFFF/png_row_stride)
               png_error(image->opaque->png_ptr, "memory image too large");
         }

@@ -2138,7 +2136,7 @@ png_image_write_main(png_voidp argument)
      ptrdiff_t row_bytes = display->row_bytes;
      png_uint_32 y = image->height;

-      for (; y > 0; --y)
+      while (y-- > 0)
      {
         png_write_row(png_ptr, row);
         row += row_bytes;
--- a/pngwtran.c
+++ b/pngwtran.c
@@ -1,7 +1,7 @@

 /* pngwtran.c - transforms the data in a row for PNG writers
 *
- * Last changed in libpng 1.6.26 [October 20, 2016]
+ * Last changed in libpng 1.6.24 [August 4, 2016]
 * Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -177,7 +177,7 @@ png_do_shift(png_row_infop row_info, png_bytep row,
   if (row_info->color_type != PNG_COLOR_TYPE_PALETTE)
   {
      int shift_start[4], shift_dec[4];
-      unsigned int channels = 0;
+      int channels = 0;

      if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
      {
--- a/pngwutil.c
+++ b/pngwutil.c
@@ -1,7 +1,7 @@

 /* pngwutil.c - utilities to write a PNG file
 *
- * Last changed in libpng 1.6.26 [October 20, 2016]
+ * Last changed in libpng 1.6.24 [August 4, 2016]
 * Copyright (c) 1998-2002,2004,2006-2016 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.)
@@ -408,7 +408,7 @@ png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,
      png_ptr->zstream.avail_out = 0;

      /* Now initialize if required, setting the new parameters, otherwise just
-       * do a simple reset to the previous parameters.
+       * to a simple reset to the previous parameters.
       */
      if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
         ret = deflateReset(&png_ptr->zstream);
@@ -675,7 +675,6 @@ png_write_IHDR(png_structrp png_ptr, png_uint_32 width, png_uint_32 height,
    int interlace_type)
 {
   png_byte buf[13]; /* Buffer to store the IHDR info */
-   int is_invalid_depth;

   png_debug(1, "in png_write_IHDR");

@@ -701,11 +700,11 @@ png_write_IHDR(png_structrp png_ptr, png_uint_32 width, png_uint_32 height,
         break;

      case PNG_COLOR_TYPE_RGB:
-         is_invalid_depth = (bit_depth != 8);
 #ifdef PNG_WRITE_16BIT_SUPPORTED
-         is_invalid_depth = (is_invalid_depth && bit_depth != 16);
+         if (bit_depth != 8 && bit_depth != 16)
+#else
+         if (bit_depth != 8)
 #endif
-         if (is_invalid_depth)
            png_error(png_ptr, "Invalid bit depth for RGB image");

         png_ptr->channels = 3;
@@ -727,22 +726,18 @@ png_write_IHDR(png_structrp png_ptr, png_uint_32 width, png_uint_32 height,
         break;

      case PNG_COLOR_TYPE_GRAY_ALPHA:
-         is_invalid_depth = (bit_depth != 8);
-#ifdef PNG_WRITE_16BIT_SUPPORTED
-         is_invalid_depth = (is_invalid_depth && bit_depth != 16);
-#endif
-         if (is_invalid_depth)
+         if (bit_depth != 8 && bit_depth != 16)
            png_error(png_ptr, "Invalid bit depth for grayscale+alpha image");

         png_ptr->channels = 2;
         break;

      case PNG_COLOR_TYPE_RGB_ALPHA:
-         is_invalid_depth = (bit_depth != 8);
 #ifdef PNG_WRITE_16BIT_SUPPORTED
-         is_invalid_depth = (is_invalid_depth && bit_depth != 16);
+         if (bit_depth != 8 && bit_depth != 16)
+#else
+         if (bit_depth != 8)
 #endif
-         if (is_invalid_depth)
            png_error(png_ptr, "Invalid bit depth for RGBA image");

         png_ptr->channels = 4;
@@ -1181,7 +1176,7 @@ png_write_sPLT(png_structrp png_ptr, png_const_sPLT_tp spalette)
   png_byte new_name[80];
   png_byte entrybuf[10];
   png_size_t entry_size = (spalette->depth == 8 ? 6 : 10);
-   png_size_t palette_size = entry_size * (png_size_t)spalette->nentries;
+   png_size_t palette_size = entry_size * spalette->nentries;
   png_sPLT_entryp ep;
 #ifndef PNG_POINTER_INDEXING_SUPPORTED
   int i;
@@ -1748,7 +1743,7 @@ png_write_pCAL(png_structrp png_ptr, png_charp purpose, png_int_32 X0,
   total_len = purpose_len + units_len + 10;

   params_len = (png_size_tp)png_malloc(png_ptr,
-       (png_alloc_size_t)((png_alloc_size_t)nparams * (sizeof (png_size_t))));
+       (png_alloc_size_t)(nparams * (sizeof (png_size_t))));

   /* Find the length of each parameter, making sure we don't count the
    * null terminator for the last parameter.
@@ -2260,7 +2255,7 @@ png_setup_sub_row(png_structrp png_ptr, const png_uint_32 bpp,
   png_bytep rp, dp, lp;
   png_size_t i;
   png_size_t sum = 0;
-   unsigned int v;
+   int v;

   png_ptr->try_row[0] = PNG_FILTER_VALUE_SUB;

@@ -2269,7 +2264,7 @@ png_setup_sub_row(png_structrp png_ptr, const png_uint_32 bpp,
   {
      v = *dp = *rp;
 #ifdef PNG_USE_ABS
-      sum += 128 - abs((int)v - 128);
+      sum += 128 - abs(v - 128);
 #else
      sum += (v < 128) ? v : 256 - v;
 #endif
@@ -2280,7 +2275,7 @@ png_setup_sub_row(png_structrp png_ptr, const png_uint_32 bpp,
   {
      v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
 #ifdef PNG_USE_ABS
-      sum += 128 - abs((int)v - 128);
+      sum += 128 - abs(v - 128);
 #else
      sum += (v < 128) ? v : 256 - v;
 #endif
@@ -2321,7 +2316,7 @@ png_setup_up_row(png_structrp png_ptr, const png_size_t row_bytes,
   png_bytep rp, dp, pp;
   png_size_t i;
   png_size_t sum = 0;
-   unsigned int v;
+   int v;

   png_ptr->try_row[0] = PNG_FILTER_VALUE_UP;

@@ -2331,7 +2326,7 @@ png_setup_up_row(png_structrp png_ptr, const png_size_t row_bytes,
   {
      v = *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
 #ifdef PNG_USE_ABS
-      sum += 128 - abs((int)v - 128);
+      sum += 128 - abs(v - 128);
 #else
      sum += (v < 128) ? v : 256 - v;
 #endif
@@ -2365,7 +2360,7 @@ png_setup_avg_row(png_structrp png_ptr, const png_uint_32 bpp,
   png_bytep rp, dp, pp, lp;
   png_uint_32 i;
   png_size_t sum = 0;
-   unsigned int v;
+   int v;

   png_ptr->try_row[0] = PNG_FILTER_VALUE_AVG;

@@ -2375,7 +2370,7 @@ png_setup_avg_row(png_structrp png_ptr, const png_uint_32 bpp,
      v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);

 #ifdef PNG_USE_ABS
-      sum += 128 - abs((int)v - 128);
+      sum += 128 - abs(v - 128);
 #else
      sum += (v < 128) ? v : 256 - v;
 #endif
@@ -2387,7 +2382,7 @@ png_setup_avg_row(png_structrp png_ptr, const png_uint_32 bpp,
          & 0xff);

 #ifdef PNG_USE_ABS
-      sum += 128 - abs((int)v - 128);
+      sum += 128 - abs(v - 128);
 #else
      sum += (v < 128) ? v : 256 - v;
 #endif
@@ -2427,7 +2422,7 @@ png_setup_paeth_row(png_structrp png_ptr, const png_uint_32 bpp,
   png_bytep rp, dp, pp, cp, lp;
   png_size_t i;
   png_size_t sum = 0;
-   unsigned int v;
+   int v;

   png_ptr->try_row[0] = PNG_FILTER_VALUE_PAETH;

@@ -2437,7 +2432,7 @@ png_setup_paeth_row(png_structrp png_ptr, const png_uint_32 bpp,
      v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);

 #ifdef PNG_USE_ABS
-      sum += 128 - abs((int)v - 128);
+      sum += 128 - abs(v - 128);
 #else
      sum += (v < 128) ? v : 256 - v;
 #endif
@@ -2470,7 +2465,7 @@ png_setup_paeth_row(png_structrp png_ptr, const png_uint_32 bpp,
      v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);

 #ifdef PNG_USE_ABS
-      sum += 128 - abs((int)v - 128);
+      sum += 128 - abs(v - 128);
 #else
      sum += (v < 128) ? v : 256 - v;
 #endif
@@ -2593,14 +2588,14 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
      png_bytep rp;
      png_size_t sum = 0;
      png_size_t i;
-      unsigned int v;
+      int v;

      {
         for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)
         {
            v = *rp;
 #ifdef PNG_USE_ABS
-            sum += 128 - abs((int)v - 128);
+            sum += 128 - abs(v - 128);
 #else
            sum += (v < 128) ? v : 256 - v;
 #endif
--- a/powerpc/filter_vsx_intrinsics.c
+++ b/powerpc/filter_vsx_intrinsics.c
@@ -1,767 +0,0 @@
-/* filter_vsx_intrinsics.c - PowerPC optimised filter functions
- *
- * Copyright (c) 2017 Glenn Randers-Pehrson
- * Written by Vadim Barkov, 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
- * and license in png.h
- */
-#include <stdio.h>
-#include <stdint.h>
-#include "../pngpriv.h"
-
-#ifdef PNG_READ_SUPPORTED
-
-/* This code requires -maltivec and -mvsx on the command line: */
-#if PNG_POWERPC_VSX_IMPLEMENTATION == 1 /* intrinsics code from pngpriv.h */
-
-#include <altivec.h>
-
-#if PNG_POWERPC_VSX_OPT > 0
-
-#ifndef __VSX__
-#  error "This code requires VSX support (POWER7 and later). Please provide -mvsx compiler flag."
-#endif
-
-#define vec_ld_unaligned(vec,data) vec = vec_vsx_ld(0,data)
-#define vec_st_unaligned(vec,data) vec_vsx_st(vec,0,data)
-
-
-/* Functions in this file look at most 3 pixels (a,b,c) to predict the 4th (d).
- * They're positioned like this:
- *    prev:  c b
- *    row:   a d
- * The Sub filter predicts d=a, Avg d=(a+b)/2, and Paeth predicts d to be
- * whichever of a, b, or c is closest to p=a+b-c.
- * ( this is taken from ../intel/filter_sse2_intrinsics.c )
- */
-
-#define vsx_declare_common_vars(row_info,row,prev_row,offset) \
-   png_byte i;\
-   png_bytep rp = row + offset;\
-   png_const_bytep pp = prev_row;\
-   png_size_t unaligned_top = 16 - (((png_size_t)rp % 16));\
-   png_size_t istop;\
-   if(unaligned_top == 16)\
-      unaligned_top = 0;\
-   istop = row_info->rowbytes;\
-   if((unaligned_top < istop))\
-      istop -= unaligned_top;\
-   else{\
-      unaligned_top = istop;\
-      istop = 0;\
-   }
-
-void png_read_filter_row_up_vsx(png_row_infop row_info, png_bytep row,
-                                png_const_bytep prev_row)
-{
-   vector unsigned char rp_vec;
-   vector unsigned char pp_vec;
-   vsx_declare_common_vars(row_info,row,prev_row,0)
-
-   /* Altivec operations require 16-byte aligned data
-    * but input can be unaligned. So we calculate
-    * unaligned part as usual.
-    */
-   for (i = 0; i < unaligned_top; i++)
-   {
-      *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
-      rp++;
-   }
-
-   /* Using SIMD while we can */
-   while( istop >= 16 )
-   {
-      rp_vec = vec_ld(0,rp);
-      vec_ld_unaligned(pp_vec,pp);
-
-      rp_vec = vec_add(rp_vec,pp_vec);
-
-      vec_st(rp_vec,0,rp);
-
-      pp += 16;
-      rp += 16;
-      istop -= 16;
-   }
-
-   if(istop > 0)
-   {
-      /* If byte count of row is not divisible by 16
-       * we will process remaining part as usual
-       */
-      for (i = 0; i < istop; i++)
-      {
-         *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
-         rp++;
-      }
-}
-
-}
-
-static const vector unsigned char VSX_LEFTSHIFTED1_4 = {16,16,16,16, 0, 1, 2, 3,16,16,16,16,16,16,16,16};
-static const vector unsigned char VSX_LEFTSHIFTED2_4 = {16,16,16,16,16,16,16,16, 4, 5, 6, 7,16,16,16,16};
-static const vector unsigned char VSX_LEFTSHIFTED3_4 = {16,16,16,16,16,16,16,16,16,16,16,16, 8, 9,10,11};
-
-static const vector unsigned char VSX_LEFTSHIFTED1_3 = {16,16,16, 0, 1, 2,16,16,16,16,16,16,16,16,16,16};
-static const vector unsigned char VSX_LEFTSHIFTED2_3 = {16,16,16,16,16,16, 3, 4, 5,16,16,16,16,16,16,16};
-static const vector unsigned char VSX_LEFTSHIFTED3_3 = {16,16,16,16,16,16,16,16,16, 6, 7, 8,16,16,16,16};
-static const vector unsigned char VSX_LEFTSHIFTED4_3 = {16,16,16,16,16,16,16,16,16,16,16,16, 9,10,11,16};
-
-static const vector unsigned char VSX_NOT_SHIFTED1_4 = {16,16,16,16, 4, 5, 6, 7,16,16,16,16,16,16,16,16};
-static const vector unsigned char VSX_NOT_SHIFTED2_4 = {16,16,16,16,16,16,16,16, 8, 9,10,11,16,16,16,16};
-static const vector unsigned char VSX_NOT_SHIFTED3_4 = {16,16,16,16,16,16,16,16,16,16,16,16,12,13,14,15};
-
-static const vector unsigned char VSX_NOT_SHIFTED1_3 = {16,16,16, 3, 4, 5,16,16,16,16,16,16,16,16,16,16};
-static const vector unsigned char VSX_NOT_SHIFTED2_3 = {16,16,16,16,16,16, 6, 7, 8,16,16,16,16,16,16,16};
-static const vector unsigned char VSX_NOT_SHIFTED3_3 = {16,16,16,16,16,16,16,16,16, 9,10,11,16,16,16,16};
-static const vector unsigned char VSX_NOT_SHIFTED4_3 = {16,16,16,16,16,16,16,16,16,16,16,16,12,13,14,16};
-
-static const vector unsigned char VSX_CHAR_ZERO = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
-#ifdef __LITTLE_ENDIAN__
-
-static const vector unsigned char VSX_CHAR_TO_SHORT1_4 = { 4,16, 5,16, 6,16, 7,16,16,16,16,16,16,16,16,16};
-static const vector unsigned char VSX_CHAR_TO_SHORT2_4 = { 8,16, 9,16,10,16,11,16,16,16,16,16,16,16,16,16};
-static const vector unsigned char VSX_CHAR_TO_SHORT3_4 = {12,16,13,16,14,16,15,16,16,16,16,16,16,16,16,16};
-
-static const vector unsigned char VSX_SHORT_TO_CHAR1_4 = {16,16,16,16, 0, 2, 4, 6,16,16,16,16,16,16,16,16};
-static const vector unsigned char VSX_SHORT_TO_CHAR2_4 = {16,16,16,16,16,16,16,16, 0, 2, 4, 6,16,16,16,16};
-static const vector unsigned char VSX_SHORT_TO_CHAR3_4 = {16,16,16,16,16,16,16,16,16,16,16,16, 0, 2, 4, 6};
-
-static const vector unsigned char VSX_CHAR_TO_SHORT1_3 = { 3,16, 4,16, 5,16,16,16,16,16,16,16,16,16,16,16};
-static const vector unsigned char VSX_CHAR_TO_SHORT2_3 = { 6,16, 7,16, 8,16,16,16,16,16,16,16,16,16,16,16};
-static const vector unsigned char VSX_CHAR_TO_SHORT3_3 = { 9,16,10,16,11,16,16,16,16,16,16,16,16,16,16,16};
-static const vector unsigned char VSX_CHAR_TO_SHORT4_3 = {12,16,13,16,14,16,16,16,16,16,16,16,16,16,16,16};
-
-static const vector unsigned char VSX_SHORT_TO_CHAR1_3 = {16,16,16, 0, 2, 4,16,16,16,16,16,16,16,16,16,16};
-static const vector unsigned char VSX_SHORT_TO_CHAR2_3 = {16,16,16,16,16,16, 0, 2, 4,16,16,16,16,16,16,16};
-static const vector unsigned char VSX_SHORT_TO_CHAR3_3 = {16,16,16,16,16,16,16,16,16, 0, 2, 4,16,16,16,16};
-static const vector unsigned char VSX_SHORT_TO_CHAR4_3 = {16,16,16,16,16,16,16,16,16,16,16,16, 0, 2, 4,16};
-
-#elif defined(__BIG_ENDIAN__)
-
-static const vector unsigned char VSX_CHAR_TO_SHORT1_4 = {16, 4,16, 5,16, 6,16, 7,16,16,16,16,16,16,16,16};
-static const vector unsigned char VSX_CHAR_TO_SHORT2_4 = {16, 8,16, 9,16,10,16,11,16,16,16,16,16,16,16,16};
-static const vector unsigned char VSX_CHAR_TO_SHORT3_4 = {16,12,16,13,16,14,16,15,16,16,16,16,16,16,16,16};
-
-static const vector unsigned char VSX_SHORT_TO_CHAR1_4 = {16,16,16,16, 1, 3, 5, 7,16,16,16,16,16,16,16,16};
-static const vector unsigned char VSX_SHORT_TO_CHAR2_4 = {16,16,16,16,16,16,16,16, 1, 3, 5, 7,16,16,16,16};
-static const vector unsigned char VSX_SHORT_TO_CHAR3_4 = {16,16,16,16,16,16,16,16,16,16,16,16, 1, 3, 5, 7};
-
-static const vector unsigned char VSX_CHAR_TO_SHORT1_3 = {16, 3,16, 4,16, 5,16,16,16,16,16,16,16,16,16,16};
-static const vector unsigned char VSX_CHAR_TO_SHORT2_3 = {16, 6,16, 7,16, 8,16,16,16,16,16,16,16,16,16,16};
-static const vector unsigned char VSX_CHAR_TO_SHORT3_3 = {16, 9,16,10,16,11,16,16,16,16,16,16,16,16,16,16};
-static const vector unsigned char VSX_CHAR_TO_SHORT4_3 = {16,12,16,13,16,14,16,16,16,16,16,16,16,16,16,16};
-
-static const vector unsigned char VSX_SHORT_TO_CHAR1_3 = {16,16,16, 1, 3, 5,16,16,16,16,16,16,16,16,16,16};
-static const vector unsigned char VSX_SHORT_TO_CHAR2_3 = {16,16,16,16,16,16, 1, 3, 5,16,16,16,16,16,16,16};
-static const vector unsigned char VSX_SHORT_TO_CHAR3_3 = {16,16,16,16,16,16,16,16,16, 1, 3, 5,16,16,16,16};
-static const vector unsigned char VSX_SHORT_TO_CHAR4_3 = {16,16,16,16,16,16,16,16,16,16,16,16, 1, 3, 5,16};
-
-#endif
-
-#define vsx_char_to_short(vec,offset,bpp) (vector unsigned short)vec_perm((vec),VSX_CHAR_ZERO,VSX_CHAR_TO_SHORT##offset##_##bpp)
-#define vsx_short_to_char(vec,offset,bpp) vec_perm(((vector unsigned char)(vec)),VSX_CHAR_ZERO,VSX_SHORT_TO_CHAR##offset##_##bpp)
-
-#ifdef PNG_USE_ABS
-#  define vsx_abs(number) abs(number)
-#else
-#  define vsx_abs(number) (number > 0) ? (number) : -(number)
-#endif
-
-void png_read_filter_row_sub4_vsx(png_row_infop row_info, png_bytep row,
-                                  png_const_bytep prev_row)
-{
-   const png_byte bpp = 4;
-
-   vector unsigned char rp_vec;
-   vector unsigned char part_vec;
-
-   vsx_declare_common_vars(row_info,row,prev_row,bpp)
-
-   PNG_UNUSED(pp)
-
-   /* Altivec operations require 16-byte aligned data
-    * but input can be unaligned. So we calculate
-    * unaligned part as usual.
-    */
-   for (i = 0; i < unaligned_top; i++)
-   {
-      *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
-      rp++;
-   }
-
-   /* Using SIMD while we can */
-   while( istop >= 16 )
-   {
-      for(i=0;i < bpp ; i++)
-      {
-         *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
-         rp++;
-      }
-      rp -= bpp;
-
-      rp_vec = vec_ld(0,rp);
-      part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED1_4);
-      rp_vec = vec_add(rp_vec,part_vec);
-
-      part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED2_4);
-      rp_vec = vec_add(rp_vec,part_vec);
-
-      part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED3_4);
-      rp_vec = vec_add(rp_vec,part_vec);
-
-      vec_st(rp_vec,0,rp);
-
-      rp += 16;
-      istop -= 16;
-   }
-
-   if(istop > 0)
-      for (i = 0; i < istop % 16; i++)
-      {
-         *rp = (png_byte)(((int)(*rp) + (int)(*(rp - bpp))) & 0xff);
-         rp++;
-      }
-
-}
-
-void png_read_filter_row_sub3_vsx(png_row_infop row_info, png_bytep row,
-                                  png_const_bytep prev_row)
-{
-   const png_byte bpp = 3;
-
-   vector unsigned char rp_vec;
-   vector unsigned char part_vec;
-
-   vsx_declare_common_vars(row_info,row,prev_row,bpp)
-
-   PNG_UNUSED(pp)
-
-   /* Altivec operations require 16-byte aligned data
-    * but input can be unaligned. So we calculate
-    * unaligned part as usual.
-    */
-   for (i = 0; i < unaligned_top; i++)
-   {
-      *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
-      rp++;
-   }
-
-   /* Using SIMD while we can */
-   while( istop >= 16 )
-   {
-      for(i=0;i < bpp ; i++)
-      {
-         *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
-         rp++;
-      }
-      rp -= bpp;
-
-      rp_vec = vec_ld(0,rp);
-      part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED1_3);
-      rp_vec = vec_add(rp_vec,part_vec);
-
-      part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED2_3);
-      rp_vec = vec_add(rp_vec,part_vec);
-
-      part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED3_3);
-      rp_vec = vec_add(rp_vec,part_vec);
-
-      part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED4_3);
-      rp_vec = vec_add(rp_vec,part_vec);
-
-      vec_st(rp_vec,0,rp);
-      rp += 15;
-      istop -= 16;
-
-      /* Since 16 % bpp = 16 % 3 = 1, last element of array must
-       * be proceeded manually
-       */
-      *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
-      rp++;
-   }
-
-   if(istop > 0)
-      for (i = 0; i < istop % 16; i++)
-      {
-         *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
-         rp++;
-      }
-}
-
-void png_read_filter_row_avg4_vsx(png_row_infop row_info, png_bytep row,
-                                  png_const_bytep prev_row)
-{
-   const png_byte bpp = 4;
-
-   vector unsigned char rp_vec;
-   vector unsigned char pp_vec;
-   vector unsigned char pp_part_vec;
-   vector unsigned char rp_part_vec;
-   vector unsigned char avg_vec;
-
-   vsx_declare_common_vars(row_info,row,prev_row,bpp)
-   rp -= bpp;
-   if(istop >= bpp)
-      istop -= bpp;
-
-   for (i = 0; i < bpp; i++)
-   {
-      *rp = (png_byte)(((int)(*rp) +
-         ((int)(*pp++) / 2 )) & 0xff);
-
-      rp++;
-   }
-
-   /* Altivec operations require 16-byte aligned data
-    * but input can be unaligned. So we calculate
-    * unaligned part as usual.
-    */
-   for (i = 0; i < unaligned_top; i++)
-   {
-      *rp = (png_byte)(((int)(*rp) +
-         (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
-
-      rp++;
-   }
-
-   /* Using SIMD while we can */
-   while( istop >= 16 )
-   {
-      for(i=0;i < bpp ; i++)
-      {
-         *rp = (png_byte)(((int)(*rp) +
-            (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
-
-         rp++;
-      }
-      rp -= bpp;
-      pp -= bpp;
-
-      vec_ld_unaligned(pp_vec,pp);
-      rp_vec = vec_ld(0,rp);
-
-      rp_part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED1_4);
-      pp_part_vec = vec_perm(pp_vec,VSX_CHAR_ZERO,VSX_NOT_SHIFTED1_4);
-      avg_vec = vec_avg(rp_part_vec,pp_part_vec);
-      avg_vec = vec_sub(avg_vec, vec_and(vec_xor(rp_part_vec,pp_part_vec),vec_splat_u8(1)));
-      rp_vec = vec_add(rp_vec,avg_vec);
-
-      rp_part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED2_4);
-      pp_part_vec = vec_perm(pp_vec,VSX_CHAR_ZERO,VSX_NOT_SHIFTED2_4);
-      avg_vec = vec_avg(rp_part_vec,pp_part_vec);
-      avg_vec = vec_sub(avg_vec, vec_and(vec_xor(rp_part_vec,pp_part_vec),vec_splat_u8(1)));
-      rp_vec = vec_add(rp_vec,avg_vec);
-
-      rp_part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED3_4);
-      pp_part_vec = vec_perm(pp_vec,VSX_CHAR_ZERO,VSX_NOT_SHIFTED3_4);
-      avg_vec = vec_avg(rp_part_vec,pp_part_vec);
-      avg_vec = vec_sub(avg_vec, vec_and(vec_xor(rp_part_vec,pp_part_vec),vec_splat_u8(1)));
-      rp_vec = vec_add(rp_vec,avg_vec);
-
-      vec_st(rp_vec,0,rp);
-
-      rp += 16;
-      pp += 16;
-      istop -= 16;
-   }
-
-   if(istop  > 0)
-      for (i = 0; i < istop % 16; i++)
-      {
-         *rp = (png_byte)(((int)(*rp) +
-            (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
-
-         rp++;
-      }
-}
-
-void png_read_filter_row_avg3_vsx(png_row_infop row_info, png_bytep row,
-                                  png_const_bytep prev_row)
-{
-  const png_byte bpp = 3;
-
-  vector unsigned char rp_vec;
-  vector unsigned char pp_vec;
-  vector unsigned char pp_part_vec;
-  vector unsigned char rp_part_vec;
-  vector unsigned char avg_vec;
-
-  vsx_declare_common_vars(row_info,row,prev_row,bpp)
-  rp -= bpp;
-  if(istop >= bpp)
-     istop -= bpp;
-
-  for (i = 0; i < bpp; i++)
-  {
-     *rp = (png_byte)(((int)(*rp) +
-        ((int)(*pp++) / 2 )) & 0xff);
-
-     rp++;
-  }
-
-  /* Altivec operations require 16-byte aligned data
-   * but input can be unaligned. So we calculate
-   * unaligned part as usual.
-   */
-  for (i = 0; i < unaligned_top; i++)
-  {
-     *rp = (png_byte)(((int)(*rp) +
-        (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
-
-     rp++;
-  }
-
-  /* Using SIMD while we can */
-  while( istop >= 16 )
-  {
-     for(i=0;i < bpp ; i++)
-     {
-        *rp = (png_byte)(((int)(*rp) +
-           (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
-
-        rp++;
-     }
-     rp -= bpp;
-     pp -= bpp;
-
-     vec_ld_unaligned(pp_vec,pp);
-     rp_vec = vec_ld(0,rp);
-
-     rp_part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED1_3);
-     pp_part_vec = vec_perm(pp_vec,VSX_CHAR_ZERO,VSX_NOT_SHIFTED1_3);
-     avg_vec = vec_avg(rp_part_vec,pp_part_vec);
-     avg_vec = vec_sub(avg_vec, vec_and(vec_xor(rp_part_vec,pp_part_vec),vec_splat_u8(1)));
-     rp_vec = vec_add(rp_vec,avg_vec);
-
-     rp_part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED2_3);
-     pp_part_vec = vec_perm(pp_vec,VSX_CHAR_ZERO,VSX_NOT_SHIFTED2_3);
-     avg_vec = vec_avg(rp_part_vec,pp_part_vec);
-     avg_vec = vec_sub(avg_vec, vec_and(vec_xor(rp_part_vec,pp_part_vec),vec_splat_u8(1)));
-     rp_vec = vec_add(rp_vec,avg_vec);
-
-     rp_part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED3_3);
-     pp_part_vec = vec_perm(pp_vec,VSX_CHAR_ZERO,VSX_NOT_SHIFTED3_3);
-     avg_vec = vec_avg(rp_part_vec,pp_part_vec);
-     avg_vec = vec_sub(avg_vec, vec_and(vec_xor(rp_part_vec,pp_part_vec),vec_splat_u8(1)));
-     rp_vec = vec_add(rp_vec,avg_vec);
-
-     rp_part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED4_3);
-     pp_part_vec = vec_perm(pp_vec,VSX_CHAR_ZERO,VSX_NOT_SHIFTED4_3);
-     avg_vec = vec_avg(rp_part_vec,pp_part_vec);
-     avg_vec = vec_sub(avg_vec, vec_and(vec_xor(rp_part_vec,pp_part_vec),vec_splat_u8(1)));
-     rp_vec = vec_add(rp_vec,avg_vec);
-
-     vec_st(rp_vec,0,rp);
-
-     rp += 15;
-     pp += 15;
-     istop -= 16;
-
-     /* Since 16 % bpp = 16 % 3 = 1, last element of array must
-      * be proceeded manually
-      */
-     *rp = (png_byte)(((int)(*rp) +
-        (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
-     rp++;
-  }
-
-  if(istop  > 0)
-     for (i = 0; i < istop % 16; i++)
-     {
-        *rp = (png_byte)(((int)(*rp) +
-           (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
-
-        rp++;
-     }
-}
-
-/* Bytewise c ? t : e. */
-#define if_then_else(c,t,e) vec_sel(e,t,c)
-
-#define vsx_paeth_process(rp,pp,a,b,c,pa,pb,pc,bpp) {\
-      c = *(pp - bpp);\
-      a = *(rp - bpp);\
-      b = *pp++;\
-      p = b - c;\
-      pc = a - c;\
-      pa = vsx_abs(p);\
-      pb = vsx_abs(pc);\
-      pc = vsx_abs(p + pc);\
-      if (pb < pa) pa = pb, a = b;\
-      if (pc < pa) a = c;\
-      a += *rp;\
-      *rp++ = (png_byte)a;\
-      }
-
-void png_read_filter_row_paeth4_vsx(png_row_infop row_info, png_bytep row,
-   png_const_bytep prev_row)
-{
-   const png_byte bpp = 4;
-
-   int a, b, c, pa, pb, pc, p;
-   vector unsigned char rp_vec;
-   vector unsigned char pp_vec;
-   vector unsigned short a_vec,b_vec,c_vec,nearest_vec;
-   vector signed short pa_vec,pb_vec,pc_vec,smallest_vec;
-
-   vsx_declare_common_vars(row_info,row,prev_row,bpp)
-   rp -= bpp;
-   if(istop >= bpp)
-      istop -= bpp;
-
-   /* Process the first pixel in the row completely (this is the same as 'up'
-    * because there is only one candidate predictor for the first row).
-    */
-   for(i = 0; i < bpp ; i++)
-   {
-      *rp = (png_byte)( *rp + *pp);
-      rp++;
-      pp++;
-   }
-
-   for(i = 0; i < unaligned_top ; i++)
-   {
-      vsx_paeth_process(rp,pp,a,b,c,pa,pb,pc,bpp)
-   }
-
-   while( istop >= 16)
-   {
-      for(i = 0; i < bpp ; i++)
-      {
-         vsx_paeth_process(rp,pp,a,b,c,pa,pb,pc,bpp)
-      }
-
-      rp -= bpp;
-      pp -= bpp;
-      rp_vec = vec_ld(0,rp);
-      vec_ld_unaligned(pp_vec,pp);
-
-      a_vec = vsx_char_to_short(vec_perm(rp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED1_4),1,4);
-      b_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_NOT_SHIFTED1_4),1,4);
-      c_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED1_4),1,4);
-      pa_vec = (vector signed short) vec_sub(b_vec,c_vec);
-      pb_vec = (vector signed short) vec_sub(a_vec , c_vec);
-      pc_vec = vec_add(pa_vec,pb_vec);
-      pa_vec = vec_abs(pa_vec);
-      pb_vec = vec_abs(pb_vec);
-      pc_vec = vec_abs(pc_vec);
-      smallest_vec = vec_min(pc_vec, vec_min(pa_vec,pb_vec));
-      nearest_vec =  if_then_else(
-            vec_cmpeq(pa_vec,smallest_vec),
-            a_vec,
-            if_then_else(
-              vec_cmpeq(pb_vec,smallest_vec),
-              b_vec,
-              c_vec
-              )
-            );
-      rp_vec = vec_add(rp_vec,(vsx_short_to_char(nearest_vec,1,4)));
-
-      a_vec = vsx_char_to_short(vec_perm(rp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED2_4),2,4);
-      b_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_NOT_SHIFTED2_4),2,4);
-      c_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED2_4),2,4);
-      pa_vec = (vector signed short) vec_sub(b_vec,c_vec);
-      pb_vec = (vector signed short) vec_sub(a_vec , c_vec);
-      pc_vec = vec_add(pa_vec,pb_vec);
-      pa_vec = vec_abs(pa_vec);
-      pb_vec = vec_abs(pb_vec);
-      pc_vec = vec_abs(pc_vec);
-      smallest_vec = vec_min(pc_vec, vec_min(pa_vec,pb_vec));
-      nearest_vec =  if_then_else(
-            vec_cmpeq(pa_vec,smallest_vec),
-            a_vec,
-            if_then_else(
-              vec_cmpeq(pb_vec,smallest_vec),
-              b_vec,
-              c_vec
-              )
-            );
-      rp_vec = vec_add(rp_vec,(vsx_short_to_char(nearest_vec,2,4)));
-
-      a_vec = vsx_char_to_short(vec_perm(rp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED3_4),3,4);
-      b_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_NOT_SHIFTED3_4),3,4);
-      c_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED3_4),3,4);
-      pa_vec = (vector signed short) vec_sub(b_vec,c_vec);
-      pb_vec = (vector signed short) vec_sub(a_vec , c_vec);
-      pc_vec = vec_add(pa_vec,pb_vec);
-      pa_vec = vec_abs(pa_vec);
-      pb_vec = vec_abs(pb_vec);
-      pc_vec = vec_abs(pc_vec);
-      smallest_vec = vec_min(pc_vec, vec_min(pa_vec,pb_vec));
-      nearest_vec =  if_then_else(
-            vec_cmpeq(pa_vec,smallest_vec),
-            a_vec,
-            if_then_else(
-              vec_cmpeq(pb_vec,smallest_vec),
-              b_vec,
-              c_vec
-              )
-            );
-      rp_vec = vec_add(rp_vec,(vsx_short_to_char(nearest_vec,3,4)));
-
-      vec_st(rp_vec,0,rp);
-
-      rp += 16;
-      pp += 16;
-      istop -= 16;
-   }
-
-   if(istop > 0)
-      for (i = 0; i < istop % 16; i++)
-      {
-         vsx_paeth_process(rp,pp,a,b,c,pa,pb,pc,bpp)
-      }
-}
-
-void png_read_filter_row_paeth3_vsx(png_row_infop row_info, png_bytep row,
-   png_const_bytep prev_row)
-{
-  const png_byte bpp = 3;
-
-  int a, b, c, pa, pb, pc, p;
-  vector unsigned char rp_vec;
-  vector unsigned char pp_vec;
-  vector unsigned short a_vec,b_vec,c_vec,nearest_vec;
-  vector signed short pa_vec,pb_vec,pc_vec,smallest_vec;
-
-  vsx_declare_common_vars(row_info,row,prev_row,bpp)
-  rp -= bpp;
-  if(istop >= bpp)
-     istop -= bpp;
-
-  /* Process the first pixel in the row completely (this is the same as 'up'
-   * because there is only one candidate predictor for the first row).
-   */
-  for(i = 0; i < bpp ; i++)
-  {
-     *rp = (png_byte)( *rp + *pp);
-     rp++;
-     pp++;
-  }
-
-  for(i = 0; i < unaligned_top ; i++)
-  {
-     vsx_paeth_process(rp,pp,a,b,c,pa,pb,pc,bpp)
-  }
-
-  while( istop >= 16)
-  {
-     for(i = 0; i < bpp ; i++)
-     {
-        vsx_paeth_process(rp,pp,a,b,c,pa,pb,pc,bpp)
-     }
-
-     rp -= bpp;
-     pp -= bpp;
-     rp_vec = vec_ld(0,rp);
-     vec_ld_unaligned(pp_vec,pp);
-
-     a_vec = vsx_char_to_short(vec_perm(rp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED1_3),1,3);
-     b_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_NOT_SHIFTED1_3),1,3);
-     c_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED1_3),1,3);
-     pa_vec = (vector signed short) vec_sub(b_vec,c_vec);
-     pb_vec = (vector signed short) vec_sub(a_vec , c_vec);
-     pc_vec = vec_add(pa_vec,pb_vec);
-     pa_vec = vec_abs(pa_vec);
-     pb_vec = vec_abs(pb_vec);
-     pc_vec = vec_abs(pc_vec);
-     smallest_vec = vec_min(pc_vec, vec_min(pa_vec,pb_vec));
-     nearest_vec =  if_then_else(
-           vec_cmpeq(pa_vec,smallest_vec),
-           a_vec,
-           if_then_else(
-             vec_cmpeq(pb_vec,smallest_vec),
-             b_vec,
-             c_vec
-             )
-           );
-     rp_vec = vec_add(rp_vec,(vsx_short_to_char(nearest_vec,1,3)));
-
-     a_vec = vsx_char_to_short(vec_perm(rp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED2_3),2,3);
-     b_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_NOT_SHIFTED2_3),2,3);
-     c_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED2_3),2,3);
-     pa_vec = (vector signed short) vec_sub(b_vec,c_vec);
-     pb_vec = (vector signed short) vec_sub(a_vec , c_vec);
-     pc_vec = vec_add(pa_vec,pb_vec);
-     pa_vec = vec_abs(pa_vec);
-     pb_vec = vec_abs(pb_vec);
-     pc_vec = vec_abs(pc_vec);
-     smallest_vec = vec_min(pc_vec, vec_min(pa_vec,pb_vec));
-     nearest_vec =  if_then_else(
-           vec_cmpeq(pa_vec,smallest_vec),
-           a_vec,
-           if_then_else(
-             vec_cmpeq(pb_vec,smallest_vec),
-             b_vec,
-             c_vec
-             )
-           );
-     rp_vec = vec_add(rp_vec,(vsx_short_to_char(nearest_vec,2,3)));
-
-     a_vec = vsx_char_to_short(vec_perm(rp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED3_3),3,3);
-     b_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_NOT_SHIFTED3_3),3,3);
-     c_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED3_3),3,3);
-     pa_vec = (vector signed short) vec_sub(b_vec,c_vec);
-     pb_vec = (vector signed short) vec_sub(a_vec , c_vec);
-     pc_vec = vec_add(pa_vec,pb_vec);
-     pa_vec = vec_abs(pa_vec);
-     pb_vec = vec_abs(pb_vec);
-     pc_vec = vec_abs(pc_vec);
-     smallest_vec = vec_min(pc_vec, vec_min(pa_vec,pb_vec));
-     nearest_vec =  if_then_else(
-           vec_cmpeq(pa_vec,smallest_vec),
-           a_vec,
-           if_then_else(
-             vec_cmpeq(pb_vec,smallest_vec),
-             b_vec,
-             c_vec
-             )
-           );
-     rp_vec = vec_add(rp_vec,(vsx_short_to_char(nearest_vec,3,3)));
-
-     a_vec = vsx_char_to_short(vec_perm(rp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED4_3),4,3);
-     b_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_NOT_SHIFTED4_3),4,3);
-     c_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED4_3),4,3);
-     pa_vec = (vector signed short) vec_sub(b_vec,c_vec);
-     pb_vec = (vector signed short) vec_sub(a_vec , c_vec);
-     pc_vec = vec_add(pa_vec,pb_vec);
-     pa_vec = vec_abs(pa_vec);
-     pb_vec = vec_abs(pb_vec);
-     pc_vec = vec_abs(pc_vec);
-     smallest_vec = vec_min(pc_vec, vec_min(pa_vec,pb_vec));
-     nearest_vec =  if_then_else(
-           vec_cmpeq(pa_vec,smallest_vec),
-           a_vec,
-           if_then_else(
-             vec_cmpeq(pb_vec,smallest_vec),
-             b_vec,
-             c_vec
-             )
-           );
-     rp_vec = vec_add(rp_vec,(vsx_short_to_char(nearest_vec,4,3)));
-
-     vec_st(rp_vec,0,rp);
-
-     rp += 15;
-     pp += 15;
-     istop -= 16;
-
-     /* Since 16 % bpp = 16 % 3 = 1, last element of array must
-      * be proceeded manually
-      */
-     vsx_paeth_process(rp,pp,a,b,c,pa,pb,pc,bpp)
-  }
-
-  if(istop > 0)
-     for (i = 0; i < istop % 16; i++)
-     {
-        vsx_paeth_process(rp,pp,a,b,c,pa,pb,pc,bpp)
-     }
-}
-
-#endif /* PNG_POWERPC_VSX_OPT > 0 */
-#endif /* PNG_POWERPC_VSX_IMPLEMENTATION == 1 (intrinsics) */
-#endif /* READ */
--- a/powerpc/powerpc_init.c
+++ b/powerpc/powerpc_init.c
@@ -1,125 +0,0 @@
-
-/* powerpc_init.c - POWERPC optimised filter functions
- *
- * Copyright (c) 2017 Glenn Randers-Pehrson
- * Written by Vadim Barkov, 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
- * and license in png.h
- */
-/* Below, after checking __linux__, various non-C90 POSIX 1003.1 functions are
- * called.
- */
-#define _POSIX_SOURCE 1
-
-#include <stdio.h>
-#include "../pngpriv.h"
-
-#ifdef PNG_READ_SUPPORTED
-
-#if PNG_POWERPC_VSX_OPT > 0
-#ifdef PNG_POWERPC_VSX_CHECK_SUPPORTED /* Do run-time checks */
-/* WARNING: it is strongly recommended that you do not build libpng with
- * run-time checks for CPU features if at all possible.  In the case of the PowerPC
- * VSX instructions there is no processor-specific way of detecting the
- * presence of the required support, therefore run-time detection is extremely
- * OS specific.
- *
- * You may set the macro PNG_POWERPC_VSX_FILE to the file name of file containing
- * a fragment of C source code which defines the png_have_vsx function.  There
- * are a number of implementations in contrib/powerpc-vsx, but the only one that
- * has partial support is contrib/powerpc-vsx/linux.c - a generic Linux
- * implementation which reads /proc/cpufino.
- */
-#ifndef PNG_POWERPC_VSX_FILE
-#  ifdef __linux__
-#     define  PNG_POWERPC_VSX_FILE "contrib/powerpc-vsx/linux_aux.c"
-#  endif
-#endif
-
-#ifdef PNG_POWERPC_VSX_FILE
-
-#include <signal.h> /* for sig_atomic_t */
-static int png_have_vsx(png_structp png_ptr);
-#include PNG_POWERPC_VSX_FILE
-
-#else  /* PNG_POWERPC_VSX_FILE */
-#  error "PNG_POWERPC_VSX_FILE undefined: no support for run-time POWERPC VSX checks"
-#endif /* PNG_POWERPC_VSX_FILE */
-#endif /* PNG_POWERPC_VSX_CHECK_SUPPORTED */
-
-void
-png_init_filter_functions_vsx(png_structp pp, unsigned int bpp)
-{
-   /* The switch statement is compiled in for POWERPC_VSX_API, the call to
-    * png_have_vsx is compiled in for POWERPC_VSX_CHECK. If both are defined
-    * the check is only performed if the API has not set the PowerPC option on
-    * or off explicitly. In this case the check controls what happens.
-    */
-
-#ifdef PNG_POWERPC_VSX_API_SUPPORTED
-   switch ((pp->options >> PNG_POWERPC_VSX) & 3)
-   {
-      case PNG_OPTION_UNSET:
-         /* Allow the run-time check to execute if it has been enabled -
-          * thus both API and CHECK can be turned on.  If it isn't supported
-          * this case will fall through to the 'default' below, which just
-          * returns.
-          */
-#endif /* PNG_POWERPC_VSX_API_SUPPORTED */
-#ifdef PNG_POWERPC_VSX_CHECK_SUPPORTED
-         {
-            static volatile sig_atomic_t no_vsx = -1; /* not checked */
-
-            if (no_vsx < 0)
-               no_vsx = !png_have_vsx(pp);
-
-            if (no_vsx)
-               return;
-         }
-#ifdef PNG_POWERPC_VSX_API_SUPPORTED
-         break;
-#endif
-#endif /* PNG_POWERPC_VSX_CHECK_SUPPORTED */
-
-#ifdef PNG_POWERPC_VSX_API_SUPPORTED
-      default: /* OFF or INVALID */
-         return;
-
-      case PNG_OPTION_ON:
-         /* Option turned on */
-         break;
-   }
-#endif
-
-   /* IMPORTANT: any new internal functions used here must be declared using
-    * PNG_INTERNAL_FUNCTION in ../pngpriv.h.  This is required so that the
-    * 'prefix' option to configure works:
-    *
-    *    ./configure --with-libpng-prefix=foobar_
-    *
-    * Verify you have got this right by running the above command, doing a build
-    * and examining pngprefix.h; it must contain a #define for every external
-    * function you add.  (Notice that this happens automatically for the
-    * initialization function.)
-    */
-   pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_vsx;
-
-   if (bpp == 3)
-   {
-      pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_vsx;
-      pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_vsx;
-      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth3_vsx;
-   }
-
-   else if (bpp == 4)
-   {
-      pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_vsx;
-      pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_vsx;
-      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth4_vsx;
-   }
-}
-#endif /* PNG_POWERPC_VSX_OPT > 0 */
-#endif /* READ */
--- a/projects/owatcom/pngconfig.mak
+++ b/projects/owatcom/pngconfig.mak
@@ -126,7 +126,7 @@ $# to work, download Brian Kernighan's awk (Brian Kernighan is the author of
 $# awk.)  You can find source code and a built executable (called awk95.exe)
 $# here:
 $#
-$#     https://www.cs.princeton.edu/~bwk/btl.mirror/
+$#     http://www.cs.princeton.edu/~bwk/btl.mirror/
 $#
 $# The executable works just fine.
 $#
--- a/projects/vstudio/README.txt
+++ b/projects/vstudio/README.txt
@@ -1,7 +1,7 @@

 VisualStudio instructions

-libpng version 1.6.30beta01 - April 1, 2017
+libpng version 1.6.25rc05 - August 30, 2016

 Copyright (c) 2010,2013,2015 Glenn Randers-Pehrson

--- a/projects/vstudio/zlib.props
+++ b/projects/vstudio/zlib.props
@@ -2,7 +2,7 @@
 <!--
 * zlib.props - location of zlib source
 *
- * libpng version 1.6.30beta01 - April 1, 2017
+ * libpng version 1.6.25rc05 - August 30, 2016
 *
 * Copyright (c) 1998-2011 Glenn Randers-Pehrson
 *
--- a/scripts/README.txt
+++ b/scripts/README.txt
@@ -1,9 +1,9 @@

-Makefiles for  libpng version 1.6.30beta01 - April 1, 2017
+Makefiles for  libpng version 1.6.25rc05 - August 30, 2016

 pnglibconf.h.prebuilt       =>  Stores configuration settings
 makefile.linux    =>  Linux/ELF makefile
-                       (gcc, creates libpng16.so.16.1.6.30beta01)
+                       (gcc, creates libpng16.so.16.1.6.25rc05)
 makefile.gcc      =>  Generic makefile (gcc, creates static libpng.a)
 makefile.knr      =>  Archaic UNIX Makefile that converts files with
                       ansi2knr (Requires ansi2knr.c from
@@ -33,12 +33,12 @@ pnglibconf.h.prebuilt       =>  Stores configuration settings
 makefile.os2      =>  OS/2 Makefile (gcc and emx, requires libpng.def)
 makefile.sco      =>  For SCO OSr5  ELF and Unixware 7 with Native cc
 makefile.sggcc    =>  Silicon Graphics (gcc,
-                       creates libpng16.so.16.1.6.30beta01)
+                       creates libpng16.so.16.1.6.25rc05)
 makefile.sgi      =>  Silicon Graphics IRIX makefile (cc, creates static lib)
 makefile.solaris  =>  Solaris 2.X makefile (gcc,
-                       creates libpng16.so.16.1.6.30beta01)
+                       creates libpng16.so.16.1.6.25rc05)
 makefile.so9      =>  Solaris 9 makefile (gcc,
-                       creates libpng16.so.16.1.6.30beta01)
+                       creates libpng16.so.16.1.6.25rc05)
 makefile.std      =>  Generic UNIX makefile (cc, creates static libpng.a)
 makefile.sunos    =>  Sun makefile
 makefile.32sunu   =>  Sun Ultra 32-bit makefile
--- a/scripts/def.c
+++ b/scripts/def.c
@@ -21,7 +21,7 @@ PNG_DFN "OS2 DESCRIPTION "PNG image compression library""
 PNG_DFN "OS2 CODE PRELOAD MOVEABLE DISCARDABLE"
 PNG_DFN ""
 PNG_DFN "EXPORTS"
-PNG_DFN ";Version 1.6.30beta01"
+PNG_DFN ";Version 1.6.25rc05"

 #define PNG_EXPORTA(ordinal, type, name, args, attributes)\
        PNG_DFN "@" SYMBOL_PREFIX "@@" name "@"
--- a/scripts/libpng-config-head.in
+++ b/scripts/libpng-config-head.in
@@ -11,7 +11,7 @@

 # Modeled after libxml-config.

-version=1.6.30beta01
+version=1.6.25rc05
 prefix=""
 libdir=""
 libs=""
--- a/scripts/libpng.pc.in
+++ b/scripts/libpng.pc.in
@@ -5,6 +5,6 @@ includedir=@includedir@/libpng16

 Name: libpng
 Description: Loads and saves PNG files
-Version: 1.6.30beta01
+Version: 1.6.25rc05
 Libs: -L${libdir} -lpng16
 Cflags: -I${includedir}
--- a/scripts/makefile.cegcc
+++ b/scripts/makefile.cegcc
@@ -23,7 +23,7 @@

 VERMAJ = 1
 VERMIN = 6
-VERMIC = 30
+VERMIC = 25
 VER = $(VERMAJ).$(VERMIN).$(VERMIC)
 NAME = libpng
 PACKAGE = $(NAME)-$(VER)
--- a/scripts/makefile.linux
+++ b/scripts/makefile.linux
@@ -10,7 +10,7 @@
 # Library name:
 LIBNAME = libpng16
 PNGMAJ = 16
-RELEASE = 30
+RELEASE = 25

 # Shared library names:
 LIBSO=$(LIBNAME).so
@@ -92,7 +92,7 @@ OBJSDLL = $(OBJS:.o=.pic.o)
 	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<

 .c.pic.o:
-	$(CC) -c $(CPPFLAGS) $(CFLAGS) -fPIC -o $@ $*.c
+	$(CC) -c $(CFLAGS) -fPIC -o $@ $*.c

 all: libpng.a $(LIBSO) pngtest pngtest-static libpng.pc libpng-config

--- a/scripts/makefile.msys
+++ b/scripts/makefile.msys
@@ -18,7 +18,7 @@ exec_prefix=$(prefix)
 # Library name:
 LIBNAME = libpng16
 PNGMAJ = 16
-RELEASE = 30
+RELEASE = 25

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

 LIB=	png16
 SHLIB_MAJOR=	0
-SHLIB_MINOR=	1.6.30beta01
+SHLIB_MINOR=	1.6.25rc05
 SRCS=	png.c pngset.c pngget.c pngrutil.c pngtrans.c pngwutil.c \
 	pngread.c pngrio.c pngwio.c pngwrite.c pngrtran.c \
 	pngwtran.c pngmem.c pngerror.c pngpread.c
--- a/scripts/makefile.netbsd
+++ b/scripts/makefile.netbsd
@@ -17,7 +17,7 @@ INCSDIR=${LOCALBASE}/include

 LIB=	png
 SHLIB_MAJOR=	16
-SHLIB_MINOR=	1.6.30beta01
+SHLIB_MINOR=	1.6.25rc05
 SRCS=	png.c pngset.c pngget.c pngrutil.c pngtrans.c pngwutil.c \
 	pngread.c pngrio.c pngwio.c pngwrite.c pngrtran.c \
 	pngwtran.c pngmem.c pngerror.c pngpread.c
--- a/scripts/makefile.openbsd
+++ b/scripts/makefile.openbsd
@@ -11,7 +11,7 @@ LIBDIR=	${PREFIX}/lib
 MANDIR= ${PREFIX}/man/cat

 SHLIB_MAJOR=	16
-SHLIB_MINOR=	1.6.30beta01
+SHLIB_MINOR=	1.6.25rc05

 LIB=	png
 SRCS=	png.c pngerror.c pngget.c pngmem.c pngpread.c \
--- a/scripts/makefile.sco
+++ b/scripts/makefile.sco
@@ -1,5 +1,5 @@
 # makefile for SCO OSr5  ELF and Unixware 7 with Native cc
-# Contributed by Mike Hopkirk (hops at sco.com) modified from Makefile.lnx
+# Contributed by Mike Hopkirk (hops@sco.com) modified from Makefile.lnx
 #   force ELF build dynamic linking, SONAME setting in lib and RPATH in app
 # Copyright (C) 2002, 2006, 2010-2014 Glenn Randers-Pehrson
 # Copyright (C) 1998 Greg Roelofs
--- a/scripts/makefile.solaris-x86
+++ b/scripts/makefile.solaris-x86
@@ -83,7 +83,7 @@ OBJSDLL = $(OBJS:.o=.pic.o)
 	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<

 .c.pic.o:
-	$(CC) -c $(CPPFLAGS) $(CFLAGS) -fPIC -o $@ $*.c
+	$(CC) -c $(CFLAGS) -fPIC -o $@ $*.c

 all: libpng.a $(LIBSO) pngtest libpng.pc libpng-config

--- a/scripts/pnglibconf.dfa
+++ b/scripts/pnglibconf.dfa
@@ -229,33 +229,6 @@ option ARM_NEON_API disabled requires ALIGNED_MEMORY enables SET_OPTION,
 option ARM_NEON_CHECK disabled requires ALIGNED_MEMORY,
   sets ARM_NEON_OPT 1

-# These options are specific to the PowerPC VSX hardware optimizations.
-#
-# POWERPC_VSX_OPT: unset: check at compile time (__PPC64__,__ALTIVEC__,__VSX__
-#                      must be defined by the compiler, typically as a result
-#                      of specifying
-#                      "-mvsx -maltivec" compiler flags)
-#                   0: disable (even if the CPU supports VSX.)
-#                   1: check at run time (via POWERPC_VSX_{API,CHECK})
-#                   2: switch on unconditionally (inadvisable - instead pass
-#                      -mvsx -maltivec to compiler options)
-#           When building libpng avoid using any setting other than '0'; '1' is
-#           set automatically when either 'API' or 'CHECK' are configured in,
-#           '2' should not be necessary as "-mvsx -maltivec" will achieve the same
-#           effect as well as applying VSX optimizations to the rest of the
-#           libpng code.
-# POWERPC_VSX_API:   (PNG_POWERPC_VSX == 1) allow the optimization to be switched on
-#                 with png_set_option
-# POWERPC_VSX_CHECK: (PNG_POWERPC_VSX == 1) compile a run-time check to see if VSX
-#                 extensions are supported. This is supported not for all OSes
-#                 (see contrib/powerpc/README)
-setting POWERPC_VSX_OPT
-option POWERPC_VSX_API disabled enables SET_OPTION,
-  sets POWERPC_VSX_OPT 1
-option POWERPC_VSX_CHECK disabled,
-  sets POWERPC_VSX_OPT 1
-
-
 # These settings configure the default compression level (0-9) and 'strategy';
 # strategy is as defined by the implementors of zlib. It describes the input
 # data and modifies the zlib parameters in an attempt to optimize the balance
--- a/scripts/pnglibconf.h.prebuilt
+++ b/scripts/pnglibconf.h.prebuilt
@@ -1,8 +1,8 @@
-/* libpng 1.6.30beta01 STANDARD API DEFINITION */
+/* libpng 1.6.25rc05 STANDARD API DEFINITION */

 /* pnglibconf.h - library build configuration */

-/* Libpng version 1.6.30beta01 - April 1, 2017 */
+/* Libpng version 1.6.25rc05 - August 30, 2016 */

 /* Copyright (c) 1998-2015 Glenn Randers-Pehrson */

@@ -20,8 +20,6 @@
 #define PNG_ALIGNED_MEMORY_SUPPORTED
 /*#undef PNG_ARM_NEON_API_SUPPORTED*/
 /*#undef PNG_ARM_NEON_CHECK_SUPPORTED*/
-/*#undef PNG_POWERPC_VSX_API_SUPPORTED*/
-/*#undef PNG_POWERPC_VSX_CHECK_SUPPORTED*/
 #define PNG_BENIGN_ERRORS_SUPPORTED
 #define PNG_BENIGN_READ_ERRORS_SUPPORTED
 /*#undef PNG_BENIGN_WRITE_ERRORS_SUPPORTED*/
--- a/scripts/symbols.def
+++ b/scripts/symbols.def
@@ -1,4 +1,4 @@
-;Version 1.6.30beta01
+;Version 1.6.25rc05
 ;--------------------------------------------------------------
 ; LIBPNG symbol list as a Win32 DEF file
 ; Contains all the symbols that can be exported from libpng
--- a/tests/badadler.png
+++ b/tests/badadler.png
--- a/tests/badcrc.png
+++ b/tests/badcrc.png
--- a/tests/pngtest
+++ b/tests/pngtest
@@ -1,4 +1,2 @@
 #!/bin/sh
-./pngtest --relaxed ${srcdir}/tests/badcrc.png
-./pngtest --relaxed ${srcdir}/tests/badadler.png
 exec ./pngtest --strict ${srcdir}/pngtest.png