Release libpng version 1.6.41

Many build scripts, ports and other third-party add-ons that are
circulating around appear to be distributed under the MIT License.
Examples include the Vcpkg build system (including the libpng port)
and the Meson build definitions (including the libpng definition).

I am, therefore, relicensing our CI scripts once more, as the sole
author (so far), just in case that any of the CI code might travel
from/to such projects. Hopefully, this one last license will stick.

Signed-off-by: Cosmin Truta <ctruta@gmail.com>

.appveyor.yml

@@ -0,0 +1,78 @@
+version: 1.6.x-{build}
+
+branches:
+  except:
+    - /libpng[0-1][0-7]/
+
+image:
+  - Visual Studio 2022
+
+shallow_clone: true
+
+environment:
+  matrix:
+    - TOOLCHAIN: vstudio
+      AUTOMATION: cmake
+      ARCH: x86
+    - TOOLCHAIN: vstudio
+      AUTOMATION: cmake
+      ARCH: x64
+    - TOOLCHAIN: vstudio
+      AUTOMATION: cmake
+      ARCH: arm64
+    - TOOLCHAIN: llvm
+      AUTOMATION: cmake
+      ARCH: x64
+    - TOOLCHAIN: msys2
+      AUTOMATION: cmake
+      ARCH: i686
+    - TOOLCHAIN: msys2
+      AUTOMATION: cmake
+      ARCH: x86_64
+    - TOOLCHAIN: msys2
+      AUTOMATION: configure
+      ARCH: i686
+    - TOOLCHAIN: msys2
+      AUTOMATION: configure
+      ARCH: x86_64
+    - TOOLCHAIN: msys2
+      AUTOMATION: makefiles
+      ARCH: i686
+    - TOOLCHAIN: msys2
+      AUTOMATION: makefiles
+      ARCH: x86_64
+
+install:
+  - 'if "%TOOLCHAIN%"=="vstudio" C:\tools\vcpkg\vcpkg.exe install zlib:%ARCH%-windows'
+  - 'if "%TOOLCHAIN%"=="vstudio" C:\tools\vcpkg\vcpkg.exe integrate install'
+  - 'if "%TOOLCHAIN%"=="llvm" C:\tools\vcpkg\vcpkg.exe install zlib:%ARCH%-windows'
+  - 'if "%TOOLCHAIN%"=="llvm" C:\tools\vcpkg\vcpkg.exe integrate install'
+
+before_build:
+  - 'if "%TOOLCHAIN%"=="vstudio" set CI_CMAKE_GENERATOR=Visual Studio 17 2022'
+  - 'if "%TOOLCHAIN%"=="vstudio" set CI_CMAKE_TOOLCHAIN_FILE=C:\tools\vcpkg\scripts\buildsystems\vcpkg.cmake'
+  - 'if "%TOOLCHAIN%"=="vstudio" if "%ARCH%"=="x86" set CI_CMAKE_GENERATOR_PLATFORM=Win32'
+  - 'if "%TOOLCHAIN%"=="vstudio" if "%ARCH%"=="x64" set CI_CMAKE_GENERATOR_PLATFORM=x64'
+  - 'if "%TOOLCHAIN%"=="vstudio" if "%ARCH%"=="arm64" set CI_CMAKE_GENERATOR_PLATFORM=ARM64'
+  - 'if "%TOOLCHAIN%"=="vstudio" if "%ARCH%"=="arm64" set CI_CMAKE_VARS=-DPNG_TESTS=0'
+  - 'if "%TOOLCHAIN%"=="llvm" set CI_CMAKE_GENERATOR=Ninja'
+  - 'if "%TOOLCHAIN%"=="llvm" set CI_CMAKE_TOOLCHAIN_FILE=C:\tools\vcpkg\scripts\buildsystems\vcpkg.cmake'
+  - 'if "%TOOLCHAIN%"=="llvm" set CI_CC=clang.exe'
+  - 'if "%TOOLCHAIN%"=="msys2" if "%AUTOMATION%"=="cmake" set CI_CMAKE_GENERATOR=Unix Makefiles'
+  - 'if "%TOOLCHAIN%"=="msys2" if "%ARCH%"=="i686" set PATH=C:\msys64\mingw32\bin;%PATH%'
+  - 'if "%TOOLCHAIN%"=="msys2" if "%ARCH%"=="x86_64" set PATH=C:\msys64\mingw64\bin;%PATH%'
+  - 'if "%TOOLCHAIN%"=="msys2" set CI_CC=%ARCH%-w64-mingw32-gcc.exe'
+  - 'set CI_CMAKE_BUILD_FLAGS=-j2'
+  - 'set CI_CTEST_FLAGS=-j2'
+  - 'set CI_MAKE_FLAGS=-j2'
+  - 'set CI_MAKEFILES=scripts/makefile.gcc scripts/makefile.msys scripts/makefile.std'
+
+build_script:
+  - 'if "%TOOLCHAIN%"=="vstudio" C:\msys64\usr\bin\bash.exe -l "%APPVEYOR_BUILD_FOLDER%\ci\ci_verify_cmake.sh"'
+  - 'if "%TOOLCHAIN%"=="llvm" C:\msys64\usr\bin\bash.exe -l "%APPVEYOR_BUILD_FOLDER%\ci\ci_verify_cmake.sh"'
+  - 'if "%TOOLCHAIN%"=="msys2" if "%AUTOMATION%"=="cmake" C:\msys64\usr\bin\bash.exe -l "%APPVEYOR_BUILD_FOLDER%\ci\ci_verify_cmake.sh"'
+  - 'if "%TOOLCHAIN%"=="msys2" if "%AUTOMATION%"=="configure" C:\msys64\usr\bin\bash.exe -l "%APPVEYOR_BUILD_FOLDER%\ci\ci_verify_configure.sh"'
+  - 'if "%TOOLCHAIN%"=="msys2" if "%AUTOMATION%"=="makefiles" C:\msys64\usr\bin\bash.exe -l "%APPVEYOR_BUILD_FOLDER%\ci\ci_verify_makefiles.sh"'
+
+cache:
+  - C:\tools\vcpkg\installed

.gitignore

@@ -0,0 +1,79 @@
+# Prerequisites
+*.d
+
+# Precompiled headers
+*.gch
+*.pch
+
+# Object files
+*.slo
+*.lo
+*.o
+*.obj
+
+# Linker output files
+*.exp
+*.ilk
+*.map
+
+# Compiled dynamic libraries
+*.dll
+*.dylib
+*.so
+*.so.*
+
+# Compiled static libraries
+*.a
+*.la
+*.lai
+*.lib
+
+# Compiled executables
+*.app/
+*.exe
+
+# Debug files
+*.dSYM/
+*.idb
+*.pdb
+*.su
+
+# Libpng configuration and build artifacts
+*.out
+.deps/
+.dirstamp
+/Makefile
+/autom4te.cache/
+/config.guess~
+/config.h.in~
+/config.log
+/config.status
+/config.sub~
+/configure~
+/install-sh~
+/libpng-config
+/libpng.pc
+/libpng.vers
+/libpng16-config
+/libpng16.pc
+/libtool
+/stamp-h1
+pnglibconf.[ch]
+pnglibconf.dfn
+pnglibconf.pre
+pngprefix.h
+
+# Libpng test artifacts
+png-fix-itxt
+pngcp
+pngfix
+pngimage
+pngstest
+pngtest
+pngunknown
+pngvalid
+timepng
+pngout.png
+
+# Libpng CI artifacts
+out/

.travis.yml

@@ -0,0 +1,33 @@
+branches:
+  except:
+    - /libpng[0-1][0-7]/
+
+language: c
+
+os:
+  - freebsd
+  - linux
+  - osx
+
+env:
+  - AUTOMATION=cmake CI_CMAKE_VARS="-DPNG_HARDWARE_OPTIMIZATIONS=ON"
+  - AUTOMATION=cmake CI_CMAKE_VARS="-DPNG_HARDWARE_OPTIMIZATIONS=OFF"
+  - AUTOMATION=configure CI_CONFIGURE_FLAGS="--enable-hardware-optimizations"
+  - AUTOMATION=configure CI_CONFIGURE_FLAGS="--disable-hardware-optimizations"
+  - AUTOMATION=makefiles
+
+matrix:
+  include:
+    - os: osx
+      env: AUTOMATION=cmake CI_CMAKE_GENERATOR=Xcode
+
+before_script:
+  - 'if test "$TRAVIS_OS_NAME" = "linux"; then export CI_CC="gcc"; else export CI_CC="clang"; fi'
+  - 'if test "$TRAVIS_OS_NAME" != "osx"; then export CI_SANITIZERS="address,undefined"; fi'
+  - 'export CI_MAKEFILES="scripts/makefile.$CI_CC scripts/makefile.std"'
+  - 'export CI_MAKE_FLAGS=-j2'
+  - 'export CI_CMAKE_BUILD_FLAGS=-j2'
+  - 'export CI_CTEST_FLAGS=-j2'
+
+script:
+  - './ci/ci_verify_$AUTOMATION.sh'

.yamllint.yml

@@ -0,0 +1,5 @@
+extends: default
+rules:
+  document-start: disable
+  document-end: disable
+  line-length: disable

ANNOUNCE

@@ -1,64 +1,66 @@
-Libpng 1.6.26 - October 20, 2016
+libpng 1.6.41 - January 24, 2024
+================================
 
-This is a public release of libpng, intended for use in production codes.
+This is a public release of libpng, intended for use in production code.
 
-Files available for download:
 
-Source files with LF line endings (for Unix/Linux) and with a
+Files available for download
-"configure" script
+----------------------------
 
-   libpng-1.6.26.tar.xz (LZMA-compressed, recommended)
+Source files with LF line endings (for Unix/Linux):
-   libpng-1.6.26.tar.gz
 
-Source files with CRLF line endings (for Windows), without the
+ * libpng-1.6.41.tar.xz (LZMA-compressed, recommended)
-"configure" script
+ * libpng-1.6.41.tar.gz (deflate-compressed)
 
-   lpng1626.7z  (LZMA-compressed, recommended)
+Source files with CRLF line endings (for Windows):
-   lpng1626.zip
+
+ * lpng1641.7z (LZMA-compressed, recommended)
+ * lpng1641.zip (deflate-compressed)
 
 Other information:
 
-   libpng-1.6.26-README.txt
+ * README.md
-   libpng-1.6.26-LICENSE.txt
+ * LICENSE.md
-   libpng-1.6.26-*.asc (armored detached GPG signatures)
+ * AUTHORS.md
+ * TRADEMARK.md
 
-Changes since the last public release (1.6.25):
 
-  Fixed handling zero length IDAT in pngfix (bug report by Agostino Sarubbo,
+Changes from version 1.6.40 to version 1.6.41
-    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
-  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 the 144 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.
-  Quieted (bogus?) clang warnings about "absolute value has no effect"
-    when PNG_USE_ABS is defined.
-  Fixed offsets in contrib/intel/intel_sse.patch
-  Changed integer constant 4294967294 to unsigned 4294967294U in pngconf.h
-    to avoid a signed/unsigned compare in the preprocessor.
-  Use zlib-1.2.8.1 inflateValidate() instead of inflateReset2() to
-    optionally avoid ADLER32 evaluation.
-  Cosmetic change, "ptr != 0" to "ptr != NULL" in png.c and pngrutil.c
-  Despammed email addresses (replaced "@" with " at ").
 
-Send comments/corrections/commendations to png-mng-implement at lists.sf.net
+ * Added SIMD-optimized code for the Loongarch LSX hardware.
-(subscription required; visit
+   (Contributed by GuXiWei, JinBo and ZhangLixia)
+ * Fixed the run-time discovery of MIPS MSA hardware.
+   (Contributed by Sui Jingfeng)
+ * Fixed an off-by-one error in the function `png_do_check_palette_indexes`,
+   which failed to recognize errors that might have existed in the first
+   column of a broken palette-encoded image. This was a benign regression
+   accidentally introduced in libpng-1.6.33. No pixel was harmed.
+   (Contributed by Adam Richter; reviewed by John Bowler)
+ * Fixed, improved and modernized the contrib/pngminus programs, i.e.,
+   png2pnm.c and pnm2png.c
+ * Removed old and peculiar portability hacks that were meant to silence
+   warnings issued by gcc version 7.1 alone.
+   (Contributed by John Bowler)
+ * Fixed and modernized the CMake file, and raised the minimum required
+   CMake version from 3.1 to 3.6.
+   (Contributed by Clinton Ingram, Timothy Lyanguzov, Tyler Kropp, et al.)
+ * Allowed the configure script to disable the building of auxiliary tools
+   and tests, thus catching up with the CMake file.
+   (Contributed by Carlo Bramini)
+ * Fixed a build issue on Mac.
+   (Contributed by Zixu Wang)
+ * Moved the Autoconf macro files to scripts/autoconf.
+ * Moved the CMake files (except for the main CMakeLists.txt) to
+   scripts/cmake and moved the list of their contributing authors to
+   scripts/cmake/AUTHORS.md
+ * Updated the CI configurations and scripts.
+ * Relicensed the CI scripts to the MIT License.
+ * Improved the test coverage.
+   (Contributed by John Bowler)
+
+
+Send comments/corrections/commendations to png-mng-implement at lists.sf.net.
+Subscription is required; visit
 https://lists.sourceforge.net/lists/listinfo/png-mng-implement
-to subscribe)
+to subscribe.
-or to glennrp at users.sourceforge.net
-
-Glenn R-P

AUTHORS

@@ -0,0 +1,60 @@
+PNG REFERENCE LIBRARY AUTHORS
+=============================
+
+This is the list of PNG Reference Library ("libpng") Contributing
+Authors, for copyright and licensing purposes.
+
+ * Adam Richter
+ * Andreas Dilger
+ * Cosmin Truta
+ * Dave Martindale
+ * Eric S. Raymond
+ * Gilles Vollant
+ * Glenn Randers-Pehrson
+ * Greg Roelofs
+ * Guy Eric Schalnat
+ * James Yu
+ * John Bowler
+ * Kevin Bracey
+ * Magnus Holmgren
+ * Mandar Sahastrabuddhe
+ * Mans Rullgard
+ * Matt Sarett
+ * Mike Klein
+ * Pascal Massimino
+ * Paul Schmidt
+ * Philippe Antoine
+ * Qiang Zhou
+ * Sam Bushell
+ * Samuel Williams
+ * Simon-Pierre Cadieux
+ * Tim Wegner
+ * Tom Lane
+ * Tom Tanner
+ * Vadim Barkov
+ * Willem van Schaik
+ * Zhijie Liang
+ * Apple Inc.
+    - Zixu Wang (王子旭)
+ * Arm Holdings
+    - Richard Townsend
+ * Google Inc.
+    - Dan Field
+    - Leon Scroggins III
+    - Matt Sarett
+    - Mike Klein
+    - Sami Boukortt
+    - Wan-Teh Chang
+ * Loongson Technology Corporation Ltd.
+    - GuXiWei (顾希伟)
+    - JinBo (金波)
+    - ZhangLixia (张利霞)
+
+The build projects, the build scripts, the test scripts, and other
+files in the "projects", "scripts" and "tests" directories, have
+other copyright owners, but are released under the libpng license.
+
+Some files in the "ci" and "contrib" directories, as well as some
+of the tools-generated files that are distributed with libpng, have
+other copyright owners, and are released under other open source
+licenses.

CHANGES

@@ -1,4 +1,3 @@
-#if 0
 CHANGES - changes for libpng
 
 version 0.1 [March 29, 1995]
@@ -205,7 +204,7 @@ Version 0.97 [January, 1998]
   Added simple sRGB support (Glenn R-P)
   Easier conditional compiling, e.g.,
     define PNG_READ/WRITE_NOT_FULLY_SUPPORTED;
-    all configurable options can be selected from command-line instead
+    all configurable options can be selected from command line instead
     of having to edit pngconf.h (Glenn R-P)
   Fixed memory leak in pngwrite.c (free info_ptr->text) (Glenn R-P)
   Added more conditions for png_do_background, to avoid changing
@@ -833,7 +832,7 @@ Version 1.0.7beta11 [May 7, 2000]
   Removed the new PNG_CREATED_READ_STRUCT and PNG_CREATED_WRITE_STRUCT modes
     which are no longer used.
   Eliminated the three new members of png_text when PNG_LEGACY_SUPPORTED is
-    defined or when neither PNG_READ_iTXt_SUPPORTED nor PNG_WRITE_iTXT_SUPPORTED
+    defined or when neither PNG_READ_iTXt_SUPPORTED nor PNG_WRITE_iTXt_SUPPORTED
     is defined.
   Made PNG_NO_READ|WRITE_iTXt the default setting, to avoid memory
     overrun when old applications fill the info_ptr->text structure directly.
@@ -943,7 +942,7 @@ Version 1.0.8 [July 24, 2000]
 Version 1.0.9beta1 [November 10, 2000]
   Fixed typo in scripts/makefile.hpux
   Updated makevms.com in scripts and contrib/* and contrib/* (Martin Zinser)
-  Fixed seqence-point bug in contrib/pngminus/png2pnm (Martin Zinser)
+  Fixed sequence-point bug in contrib/pngminus/png2pnm (Martin Zinser)
   Changed "cdrom.com" in documentation to "libpng.org"
   Revised pnggccrd.c to get it all working, and updated makefile.gcmmx (Greg).
   Changed type of "params" from voidp to png_voidp in png_read|write_png().
@@ -1454,7 +1453,7 @@ Version 1.2.6beta4 [July 28, 2004]
     sequential read support.
   Added some "#if PNG_WRITE_SUPPORTED" blocks.
   Added #ifdef to remove some redundancy in png_malloc_default().
-  Use png_malloc instead of png_zalloc to allocate the pallete.
+  Use png_malloc instead of png_zalloc to allocate the palette.
 
 Version 1.0.16rc1 and 1.2.6rc1 [August 4, 2004]
   Fixed buffer overflow vulnerability (CVE-2004-0597) in png_handle_tRNS().
@@ -2296,7 +2295,7 @@ Version 1.4.0beta58 [May 14, 2009]
   Clarified usage of sig_bit versus sig_bit_p in example.c (Vincent Torri)
 
 Version 1.4.0beta59 [May 15, 2009]
-  Reformated sources in libpng style (3-space intentation, comment format)
+  Reformatted sources in libpng style (3-space indentation, comment format)
   Fixed typo in libpng docs (PNG_FILTER_AVE should be PNG_FILTER_AVG)
   Added sections about the git repository and our coding style to the
     documentation
@@ -2662,7 +2661,7 @@ Version 1.4.1beta06 [January 28, 2010]
 
 Version 1.4.1beta07 [February 6, 2010]
   Folded some long lines in the source files.
-  Added defineable PNG_USER_CHUNK_CACHE_MAX, PNG_USER_CHUNK_MALLOC_MAX,
+  Added definable PNG_USER_CHUNK_CACHE_MAX, PNG_USER_CHUNK_MALLOC_MAX,
     and a PNG_USER_LIMITS_SUPPORTED flag.
   Eliminated use of png_ptr->irowbytes and reused the slot in png_ptr as
     png_ptr->png_user_chunk_malloc_max.
@@ -3259,7 +3258,7 @@ Version 1.5.2beta01 [February 13, 2011]
   Revised PNG_EXPORTA macro to not use an empty parameter, to accommodate the
     old VisualC++ preprocessor.
   Turned on interlace handling in png_read_png().
-  Fixed gcc pendantic warnings.
+  Fixed gcc pedantic warnings.
   Handle longjmp in Cygwin.
   Fixed png_get_current_row_number() in the interlaced case.
   Cleaned up ALPHA flags and transformations.
@@ -3359,7 +3358,7 @@ Version 1.5.3beta05 [May 6, 2011]
   Pass "" instead of '\0' to png_default_error() in png_err().  This mistake
     was introduced in libpng-1.2.20beta01.  This fixes CVE-2011-2691.
   Added PNG_WRITE_OPTIMIZE_CMF_SUPPORTED macro to make the zlib "CMF" byte
-    optimization configureable.
+    optimization configurable.
   IDAT compression failed if preceded by a compressed text chunk (bug
     introduced in libpng-1.5.3beta01-02).  This was because the attempt to
     reset the zlib stream in png_write_IDAT happened after the first IDAT
@@ -3643,7 +3642,7 @@ Version 1.5.6beta05 [October 12, 2011]
   Fixed bug in png_write_chunk_header() debug print, introduced in 1.5.6beta01.
 
 Version 1.5.6beta06 [October 17, 2011]
-  Removed two redundant tests for unitialized row.
+  Removed two redundant tests for uninitialized row.
   Fixed a relatively harmless memory overwrite in compressed text writing
     with a 1 byte zlib buffer.
   Add ability to call png_read_update_info multiple times to pngvalid.c.
@@ -3689,7 +3688,7 @@ Version 1.5.7beta01 [November 4, 2011]
     crash.  The pngmem.c implementation of png_malloc() included a cast
     to png_size_t which would fail on large allocations on 16-bit systems.
   Fix for the preprocessor of the Intel C compiler. The preprocessor
-    splits adjacent @ signs with a space; this changes the concatentation
+    splits adjacent @ signs with a space; this changes the concatenation
     token from @-@-@ to PNG_JOIN; that should work with all compiler
     preprocessors.
   Paeth filter speed improvements from work by Siarhei Siamashka. This
@@ -3735,7 +3734,7 @@ Version 1.5.7beta03 [November 17, 2011]
     gray (on palette) itself.
   Fixes for C++ compilation using g++ When libpng source is compiled
     using g++. The compiler imposes C++ rules on the C source; thus it
-    is desireable to make the source work with either C or C++ rules
+    is desirable to make the source work with either C or C++ rules
     without throwing away useful error information.  This change adds
     png_voidcast to allow C semantic (void*) cases or the corresponding
     C++ static_cast operation, as appropriate.
@@ -3887,7 +3886,7 @@ Version 1.6.0beta06 [January 24, 2012]
 Version 1.6.0beta07 [January 28, 2012]
   Eliminated Intel icc/icl compiler warnings. The Intel (GCC derived)
     compiler issues slightly different warnings from those issued by the
-    current vesions of GCC. This eliminates those warnings by
+    current versions of GCC. This eliminates those warnings by
     adding/removing casts and small code rewrites.
   Updated configure.ac from autoupdate: added --enable-werror option.
     Also some layout regularization and removal of introduced tab characters
@@ -3920,7 +3919,7 @@ Version 1.6.0beta08 [February 1, 2012]
     version checking to configure.ac
   Improved pngstest speed by not doing redundant tests and add const to
     the background parameter of png_image_finish_read. The --background
-    option is now done automagically only when required, so that commandline
+    option is now done automagically only when required, so that command-line
     option no longer exists.
   Cleaned up pngpriv.h to consistently declare all functions and data.
     Also eliminated PNG_CONST_DATA, which is apparently not needed but we
@@ -4061,7 +4060,7 @@ Version 1.6.0beta17 [March 10, 2012]
     possible to call png_inflate() incrementally.  A warning is no longer
     issued if the language tag or translated keyword in the iTXt chunk
     has zero length.
-  If benign errors are disabled use maximum window on ancilliary inflate.
+  If benign errors are disabled use maximum window on ancillary inflate.
     This works round a bug introduced in 1.5.4 where compressed ancillary
     chunks could end up with a too-small windowBits value in the deflate
     header.
@@ -4176,7 +4175,7 @@ Version 1.6.0beta27 [August 11, 2012]
     declared even though the functions are never actually defined.  This
     change provides a dummy definition so that the declarations work, yet any
     implementation will fail to compile because of an incomplete type.
-  Re-eliminated the use of strcpy() in pngtest.c.  An unncessary use of
+  Re-eliminated the use of strcpy() in pngtest.c.  An unnecessary use of
     strcpy() was accidentally re-introduced in libpng16; this change replaces
     it with strncpy().
   Eliminated use of png_sizeof(); use sizeof() instead.
@@ -4309,7 +4308,7 @@ Version 1.6.0beta31 [November 1, 2012]
     resulting in VS2010 having to update the files.
   Removed non-working ICC profile support code that was mostly added to
     libpng-1.6.0beta29 and beta30. There was too much code for too little
-    gain; implementing full ICC color correction may be desireable but is left
+    gain; implementing full ICC color correction may be desirable but is left
     up to applications.
 
 Version 1.6.0beta32 [November 25, 2012]
@@ -4592,7 +4591,7 @@ Version 1.6.3beta07 [June 8, 2013]
     the optimizations ('check' vs 'api') are exposed in the public header files
     except that the new setting PNG_ARM_NEON_OPT documents how libpng makes the
     decision about whether or not to use the optimizations.
-  Protect symbol prefixing against CC/CPPFLAGS/CFLAGS useage.
+  Protect symbol prefixing against CC/CPPFLAGS/CFLAGS usage.
     Previous iOS/Xcode fixes for the ARM NEON optimizations moved the test
     on __ARM_NEON__ from configure time to compile time.  This breaks symbol
     prefixing because the definition of the special png_init_filter_functions
@@ -5635,7 +5634,7 @@ Version 1.6.24beta02 [June 23, 2016]
     to All and adds a list of the warnings that need to be turned off.  This is
     semi-documentary; the intent is to tell libpng users which warnings have
     been examined and judged non-fixable at present.  The warning about
-    structure padding is fixable, but it would be a signficant change (moving
+    structure padding is fixable, but it would be a significant change (moving
     structure members around).
 
 Version 1.6.24beta03 [July 4, 2016]
@@ -5754,11 +5753,415 @@ 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 ").
 
-Send comments/corrections/commendations to png-mng-implement at lists.sf.net
+Version 1.6.27beta01 [November 2, 2016]
-(subscription required; visit
+  Restrict the new ADLER32-skipping to IDAT chunks.  It broke iCCP chunk
-https://lists.sourceforge.net/lists/listinfo/png-mng-implement
+    handling: an erroneous iCCP chunk would throw a png_error and reject the
-to subscribe)
+    entire PNG image instead of rejecting just the iCCP chunk with a warning,
-or to glennrp at users.sourceforge.net
+    if built with zlib-1.2.8.1.
 
-Glenn R-P
+Version 1.6.27rc01 [December 27, 2016]
-#endif
+  Control ADLER32 checking with new PNG_IGNORE_ADLER32 option. Fixes
+    an endless loop when handling erroneous ADLER32 checksums; bug
+    introduced in libpng-1.6.26.
+  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 accommodate
+    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).
+
+Version 1.6.30beta02 [April 22, 2017]
+  Document need to check for integer overflow when allocating a pixel
+    buffer for multiple rows in contrib/gregbook, contrib/pngminus,
+    example.c, and in the manual (suggested by Jaeseung Choi). This
+    is similar to the bug reported against pngquant in CVE-2016-5735.
+  Removed reference to the obsolete PNG_SAFE_LIMITS macro in the documentation.
+
+Version 1.6.30beta03 [May 22, 2017]
+  Check for integer overflow in contrib/visupng and contrib/tools/genpng.
+  Do not double evaluate CMAKE_SYSTEM_PROCESSOR in CMakeLists.txt.
+  Test CMAKE_HOST_WIN32 instead of WIN32 in CMakeLists.txt.
+  Fix some URL in documentation.
+
+Version 1.6.30beta04 [June 7, 2017]
+  Avoid writing an empty IDAT when the last IDAT exactly fills the
+    compression buffer (bug report by Brian Baird). This bug was
+    introduced in libpng-1.6.0.
+
+Version 1.6.30rc01 [June 14, 2017]
+  No changes.
+
+Version 1.6.30rc02 [June 25, 2017]
+  Update copyright year in pnglibconf.h, make ltmain.sh executable.
+  Add a reference to the libpng.download site in README.
+
+Version 1.6.30 [June 28, 2017]
+  No changes.
+
+Version 1.6.31beta01 [July 5, 2017]
+  Guard the definition of _POSIX_SOURCE in pngpriv.h (AIX already defines it;
+    bug report by Michael Felt).
+  Revised pngpriv.h to work around failure to compile arm/filter_neon.S
+    ("typedef" directive is unrecognized by the assembler). The problem
+    was introduced in libpng-1.6.30beta01.
+  Added "Requires: zlib" to libpng.pc.in (Pieter Neerincx).
+  Added special case for FreeBSD in arm/filter_neon.S (Maya Rashish).
+
+Version 1.6.31beta02 [July 8, 2017]
+  Added instructions for disabling hardware optimizations in INSTALL.
+  Added "--enable-hardware-optimizations" configuration flag to enable
+    or disable all hardware optimizations with one flag.
+
+Version 1.6.31beta03 [July 9, 2017]
+  Updated CMakeLists.txt to add INTEL_SSE and MIPS_MSA platforms.
+  Changed "int" to "png_size_t" in intel/filter_sse2.c to prevent
+    possible integer overflow (Bug report by John Bowler).
+  Quieted "declaration after statement" warnings in intel/filter_sse2.c.
+  Added scripts/makefile-linux-opt, which has hardware optimizations enabled.
+
+Version 1.6.31beta04 [July 11, 2017]
+  Removed one of the GCC-7.1.0 'strict-overflow' warnings that result when
+    integers appear on both sides of a compare.  Worked around the others by
+    forcing the strict-overflow setting in the relevant functions to a level
+    where they are not reported (John Bowler).
+  Changed "FALL THROUGH" comments to "FALLTHROUGH" because GCC doesn't like
+    the space.
+  Worked around some C-style casts from (void*) because g++ 5.4.0 objects
+    to them.
+  Increased the buffer size for 'sprint' to pass the gcc 7.1.0 'sprint
+    overflow' check that is on by default with -Wall -Wextra.
+
+Version 1.6.31beta05 [July 13, 2017]
+  Added eXIf chunk support.
+
+Version 1.6.31beta06 [July 17, 2017]
+  Added a minimal eXIf chunk (with Orientation and FocalLengthIn35mmFilm
+    tags) to pngtest.png.
+
+Version 1.6.31beta07 [July 18, 2017]
+  Revised the eXIf chunk in pngtest.png to fix "Bad IFD1 Directory" warning.
+
+Version 1.6.31rc01 [July 19, 2017]
+  No changes.
+
+Version 1.6.31rc02 [July 25, 2017]
+  Fixed typo in example.c (png_free_image should be png_image_free) (Bug
+    report by John Smith)
+
+Version 1.6.31 [July 27, 2017]
+  No changes.
+
+Version 1.6.32beta01 [July 31, 2017]
+  Avoid possible NULL dereference in png_handle_eXIf when benign_errors
+    are allowed. Avoid leaking the input buffer "eXIf_buf".
+  Eliminated png_ptr->num_exif member from pngstruct.h and added num_exif
+    to arguments for png_get_eXIf() and png_set_eXIf().
+  Added calls to png_handle_eXIf(() in pngread.c and png_write_eXIf() in
+    pngwrite.c, and made various other fixes to png_write_eXIf().
+  Changed name of png_get_eXIF and png_set_eXIf() to png_get_eXIf_1() and
+    png_set_eXIf_1(), respectively, to avoid breaking API compatibility
+    with libpng-1.6.31.
+
+Version 1.6.32beta02 [August 1, 2017]
+  Updated contrib/libtests/pngunknown.c with eXIf chunk.
+
+Version 1.6.32beta03 [August 2, 2017]
+  Initialized btoa[] in pngstest.c
+  Stop memory leak when returning from png_handle_eXIf() with an error
+    (Bug report from the OSS-fuzz project).
+
+Version 1.6.32beta04 [August 2, 2017]
+  Replaced local eXIf_buf with info_ptr->eXIf_buf in png_handle_eXIf().
+  Update libpng.3 and libpng-manual.txt about eXIf functions.
+
+Version 1.6.32beta05 [August 2, 2017]
+  Restored png_get_eXIf() and png_set_eXIf() to maintain API compatibility.
+
+Version 1.6.32beta06 [August 2, 2017]
+  Removed png_get_eXIf_1() and png_set_eXIf_1().
+
+Version 1.6.32beta07 [August 3, 2017]
+  Check length of all chunks except IDAT against user limit to fix an
+    OSS-fuzz issue (Fixes CVE-2017-12652).
+
+Version 1.6.32beta08 [August 3, 2017]
+  Check length of IDAT against maximum possible IDAT size, accounting
+    for height, rowbytes, interlacing and zlib/deflate overhead.
+  Restored png_get_eXIf_1() and png_set_eXIf_1(), because strlen(eXIf_buf)
+    does not work (the eXIf chunk data can contain zeroes).
+
+Version 1.6.32beta09 [August 3, 2017]
+  Require cmake-2.8.8 in CMakeLists.txt. Revised symlink creation,
+    no longer using deprecated cmake LOCATION feature (Clifford Yapp).
+  Fixed five-byte error in the calculation of IDAT maximum possible size.
+
+Version 1.6.32beta10 [August 5, 2017]
+  Moved chunk-length check into a png_check_chunk_length() private
+    function (Suggested by Max Stepin).
+  Moved bad pngs from tests to contrib/libtests/crashers
+  Moved testing of bad pngs into a separate tests/pngtest-badpngs script
+  Added the --xfail (expected FAIL) option to pngtest.c. It writes XFAIL
+    in the output but PASS for the libpng test.
+  Require cmake-3.0.2 in CMakeLists.txt (Clifford Yapp).
+  Fix "const" declaration info_ptr argument to png_get_eXIf_1() and the
+    num_exif argument to png_get_eXIf_1() (Github Issue 171).
+
+Version 1.6.32beta11 [August 7, 2017]
+  Added "eXIf" to "chunks_to_ignore[]" in png_set_keep_unknown_chunks().
+  Added huge_IDAT.png and empty_ancillary_chunks.png to testpngs/crashers.
+  Make pngtest --strict, --relax, --xfail options imply -m (multiple).
+  Removed unused chunk_name parameter from png_check_chunk_length().
+  Relocated setting free_me for eXIf data, to stop an OSS-fuzz leak.
+  Initialize profile_header[] in png_handle_iCCP() to fix OSS-fuzz issue.
+  Initialize png_ptr->row_buf[0] to 255 in png_read_row() to fix OSS-fuzz UMR.
+  Attempt to fix a UMR in png_set_text_2() to fix OSS-fuzz issue.
+  Increase minimum zlib stream from 9 to 14 in png_handle_iCCP(), to account
+    for the minimum 'deflate' stream, and relocate the test to a point
+    after the keyword has been read.
+  Check that the eXIf chunk has at least 2 bytes and begins with "II" or "MM".
+
+Version 1.6.32rc01 [August 18, 2017]
+  Added a set of "huge_xxxx_chunk.png" files to contrib/testpngs/crashers,
+    one for each known chunk type, with length = 2GB-1.
+  Check for 0 return from png_get_rowbytes() and added some (size_t) typecasts
+    in contrib/pngminus/*.c to stop some Coverity issues (162705, 162706,
+    and 162707).
+  Renamed chunks in contrib/testpngs/crashers to avoid having files whose
+    names differ only in case; this causes problems with some platforms
+    (github issue #172).
+
+Version 1.6.32rc02 [August 22, 2017]
+  Added contrib/oss-fuzz directory which contains files used by the oss-fuzz
+    project (https://github.com/google/oss-fuzz/tree/master/projects/libpng).
+
+Version 1.6.32 [August 24, 2017]
+  No changes.
+
+Version 1.6.33beta01 [August 28, 2017]
+  Added PNGMINUS_UNUSED macro to contrib/pngminus/p*.c and added missing
+    parenthesis in contrib/pngminus/pnm2png.c (bug report by Christian Hesse).
+  Fixed off-by-one error in png_do_check_palette_indexes() (Bug report
+    by Mick P., Source Forge Issue #269).
+
+Version 1.6.33beta02 [September 3, 2017]
+  Initialize png_handler.row_ptr in contrib/oss-fuzz/libpng_read_fuzzer.cc
+    to fix shortlived oss-fuzz issue 3234.
+  Compute a larger limit on IDAT because some applications write a deflate
+    buffer for each row (Bug report by Andrew Church).
+  Use current date (DATE) instead of release-date (RDATE) in last
+    changed date of contrib/oss-fuzz files.
+  Enabled ARM support in CMakeLists.txt (Bernd Kuhls).
+
+Version 1.6.33beta03 [September 14, 2017]
+  Fixed incorrect typecast of some arguments to png_malloc() and
+    png_calloc() that were png_uint_32 instead of png_alloc_size_t
+    (Bug report by "irwir" in Github libpng issue #175).
+  Use pnglibconf.h.prebuilt when building for ANDROID with cmake (Github
+    issue 162, by rcdailey).
+
+Version 1.6.33rc01 [September 20, 2017]
+  Initialize memory allocated by png_inflate to zero, using memset, to
+    stop an oss-fuzz "use of uninitialized value" detection in png_set_text_2()
+    due to truncated iTXt or zTXt chunk.
+  Initialize memory allocated by png_read_buffer to zero, using memset, to
+    stop an oss-fuzz "use of uninitialized value" detection in
+    png_icc_check_tag_table() due to truncated iCCP chunk.
+  Removed a redundant test (suggested by "irwir" in Github issue #180).
+
+Version 1.6.33rc02 [September 23, 2017]
+  Added an interlaced version of each file in contrib/pngsuite.
+  Relocate new memset() call in pngrutil.c.
+  Removed more redundant tests (suggested by "irwir" in Github issue #180).
+  Add support for loading images with associated alpha in the Simplified
+    API (Samuel Williams).
+
+Version 1.6.33 [September 28, 2017]
+  Revert contrib/oss-fuzz/libpng_read_fuzzer.cc to libpng-1.6.32 state.
+  Initialize png_handler.row_ptr in contrib/oss-fuzz/libpng_read_fuzzer.cc
+  Add end_info structure and png_read_end() to the libpng fuzzer.
+
+Version 1.6.34 [September 29, 2017]
+  Removed contrib/pngsuite/i*.png; some of them caused test failures.
+
+Version 1.6.35beta01 [March 6, 2018]
+  Restored 21 of the contrib/pngsuite/i*.png, which do not cause test
+    failures. Placed the remainder in contrib/pngsuite/interlaced/i*.png.
+  Added calls to png_set_*() transforms commonly used by browsers to
+    the fuzzer.
+  Removed some unnecessary brackets in pngrtran.c
+  Fixed miscellaneous typos (Patch by github user "luzpaz").
+  Change "ASM C" to "C ASM" in CMakeLists.txt
+  Fixed incorrect handling of bKGD chunk in sub-8-bit files (Cosmin)
+  Added hardware optimization directories to zip and 7z distributions.
+  Fixed incorrect bitmask for options.
+  Fixed many spelling typos.
+
+Version 1.6.35beta02 [March 28, 2018]
+  Make png_get_iCCP consistent with man page (allow compression-type argument
+  to be NULL, bug report by Lenard Szolnoki).
+
+Version 1.6.35 [July 15, 2018]
+  Replaced the remaining uses of png_size_t with size_t (Cosmin)
+  Fixed the calculation of row_factor in png_check_chunk_length
+    (reported by Thuan Pham in SourceForge issue #278)
+  Added missing parentheses to a macro definition
+    (suggested by "irwir" in GitHub issue #216)
+
+Version 1.6.36 [December 1, 2018]
+  Optimized png_do_expand_palette for ARM processors.
+  Improved performance by around 10-22% on a recent ARM Chromebook.
+    (Contributed by Richard Townsend, ARM Holdings)
+  Fixed manipulation of machine-specific optimization options.
+    (Contributed by Vicki Pfau)
+  Used memcpy instead of manual pointer arithmetic on Intel SSE2.
+    (Contributed by Samuel Williams)
+  Fixed build errors with MSVC on ARM64.
+    (Contributed by Zhijie Liang)
+  Fixed detection of libm in CMakeLists.
+    (Contributed by Cameron Cawley)
+  Fixed incorrect creation of pkg-config file in CMakeLists.
+    (Contributed by Kyle Bentley)
+  Fixed the CMake build on Windows MSYS by avoiding symlinks.
+  Fixed a build warning on OpenBSD.
+    (Contributed by Theo Buehler)
+  Fixed various typos in comments.
+    (Contributed by "luz.paz")
+  Raised the minimum required CMake version from 3.0.2 to 3.1.
+  Removed yet more of the vestigial support for pre-ANSI C compilers.
+  Removed ancient makefiles for ancient systems that have been broken
+    across all previous libpng-1.6.x versions.
+  Removed the Y2K compliance statement and the export control
+    information.
+  Applied various code style and documentation fixes.
+
+Version 1.6.37 [April 14, 2019]
+  Fixed a use-after-free vulnerability (CVE-2019-7317) in png_image_free.
+  Fixed a memory leak in the ARM NEON implementation of png_do_expand_palette.
+  Fixed a memory leak in pngtest.c.
+  Fixed two vulnerabilities (CVE-2018-14048, CVE-2018-14550) in
+    contrib/pngminus; refactor.
+  Changed the license of contrib/pngminus to MIT; refresh makefile and docs.
+    (Contributed by Willem van Schaik)
+  Fixed a typo in the libpng license v2.
+    (Contributed by Miguel Ojeda)
+  Added makefiles for AddressSanitizer-enabled builds.
+  Cleaned up various makefiles.
+
+Version 1.6.38 [September 14, 2022]
+  Added configurations and scripts for continuous integration.
+  Fixed various errors in the handling of tRNS, hIST and eXIf.
+  Implemented many stability improvements across all platforms.
+  Updated the internal documentation.
+
+Version 1.6.39 [November 20, 2022]
+  Changed the error handler of oversized chunks (i.e. larger than
+    PNG_USER_CHUNK_MALLOC_MAX) from png_chunk_error to png_benign_error.
+  Fixed a buffer overflow error in contrib/tools/pngfix.
+  Fixed a memory leak (CVE-2019-6129) in contrib/tools/pngcp.
+  Disabled the ARM Neon optimizations by default in the CMake file,
+    following the default behavior of the configure script.
+  Allowed configure.ac to work with the trunk version of autoconf.
+  Removed the support for "install" targets from the legacy makefiles;
+    removed the obsolete makefile.cegcc.
+  Cleaned up the code and updated the internal documentation.
+
+Version 1.6.40 [June 21, 2023]
+  Fixed the eXIf chunk multiplicity checks.
+  Fixed a memory leak in pCAL processing.
+  Corrected the validity report about tRNS inside png_get_valid().
+  Fixed various build issues on *BSD, Mac and Windows.
+  Updated the configurations and the scripts for continuous integration.
+  Cleaned up the code, the build scripts, and the documentation.
+
+Version 1.6.41 [January 24, 2024]
+  Added SIMD-optimized code for the Loongarch LSX hardware.
+    (Contributed by GuXiWei, JinBo and ZhangLixia)
+  Fixed the run-time discovery of MIPS MSA hardware.
+    (Contributed by Sui Jingfeng)
+  Fixed an off-by-one error in the function `png_do_check_palette_indexes`,
+    which failed to recognize errors that might have existed in the first
+    column of a broken palette-encoded image. This was a benign regression
+    accidentally introduced in libpng-1.6.33. No pixel was harmed.
+    (Contributed by Adam Richter; reviewed by John Bowler)
+  Fixed, improved and modernized the contrib/pngminus programs, i.e.,
+    png2pnm.c and pnm2png.c
+  Removed old and peculiar portability hacks that were meant to silence
+    warnings issued by gcc version 7.1 alone.
+    (Contributed by John Bowler)
+  Fixed and modernized the CMake file, and raised the minimum required
+    CMake version from 3.1 to 3.6.
+    (Contributed by Clinton Ingram, Timothy Lyanguzov, Tyler Kropp, et al.)
+  Allowed the configure script to disable the building of auxiliary tools
+    and tests, thus catching up with the CMake file.
+    (Contributed by Carlo Bramini)
+  Fixed a build issue on Mac.
+    (Contributed by Zixu Wang)
+  Moved the Autoconf macro files to scripts/autoconf.
+  Moved the CMake files (except for the main CMakeLists.txt) to
+    scripts/cmake and moved the list of their contributing authors to
+    scripts/cmake/AUTHORS.md
+  Updated the CI configurations and scripts.
+  Relicensed the CI scripts to the MIT License.
+  Improved the test coverage.
+    (Contributed by John Bowler)
+
+Send comments/corrections/commendations to png-mng-implement at lists.sf.net.
+Subscription is required; visit
+https://lists.sourceforge.net/lists/listinfo/png-mng-implement
+to subscribe.

INSTALL

@@ -16,10 +16,11 @@ Contents
       XI. Prepending a prefix to exported symbols
      XII. Configuring for compiler xxx:
     XIII. Removing unwanted object code
-     XIV. Changes to the build and configuration of libpng in libpng-1.5.x
+     XIV. Enabling or disabling hardware optimizations
-      XV. Setjmp/longjmp issues
+      XV. Changes to the build and configuration of libpng in libpng-1.5.x
-     XVI. Common linking failures
+     XVI. Setjmp/longjmp issues
-    XVII. Other sources of information about libpng
+    XVII. Common linking failures
+   XVIII. Other sources of information about libpng
 
 I. Simple installation
 
@@ -78,8 +79,8 @@ Or you can use one of the "projects" in the "projects" directory.
 
 Before installing libpng, you must first install zlib, if it
 is not already on your system.  zlib can usually be found
-wherever you got libpng; otherwise go to http://zlib.net.  You can place
+wherever you got libpng; otherwise go to https://zlib.net/.  You can
-zlib in the same directory as libpng or in another directory.
+place zlib in the same directory as libpng or in another directory.
 
 If your system already has a preinstalled zlib you will still need
 to have access to the zlib.h and zconf.h include files that
@@ -127,16 +128,18 @@ Your directory structure should look like this:
           README
           *.h, *.c  => libpng source files
           CMakeLists.txt    =>  "cmake" script
+          ci
+             ci_*.sh
           configuration files:
              configure.ac, configure, Makefile.am, Makefile.in,
              autogen.sh, config.guess, ltmain.sh, missing, libpng.pc.in,
              libpng-config.in, aclocal.m4, config.h.in, config.sub,
-             depcomp, install-sh, mkinstalldirs, test-pngtest.sh
+             depcomp, install-sh, mkinstalldirs, test-pngtest.sh, etc.
           contrib
              arm-neon, conftest, examples, gregbook, libtests, pngminim,
              pngminus, pngsuite, tools, visupng
           projects
-             cbuilder5, owatcom, visualc71, vstudio, xcode
+             owatcom, visualc71, vstudio
           scripts
              makefile.*
              *.def (module definition files)
@@ -144,7 +147,7 @@ Your directory structure should look like this:
           pngtest.png
           etc.
       zlib
-          README, *.h, *.c contrib, etc.
+          README, *.h, *.c, contrib, etc.
 
 If the line endings in the files look funny, you may wish to get the other
 distribution of libpng.  It is available in both tar.gz (UNIX style line
@@ -152,28 +155,27 @@ endings) and zip (DOS style line endings) formats.
 
 VI. Building with project files
 
-If you are building libpng with MSVC, you can enter the
+If you are building libpng with Microsoft Visual Studio, you can enter
-libpng projects\visualc71 or vstudio directory and follow the instructions
+the directory projects\visualc71 or projects\vstudio and follow the
-in README.txt.
+instructions in README.txt.
 
-Otherwise enter the zlib directory and follow the instructions in zlib/README,
+Otherwise, enter the zlib directory and follow the instructions in
-then come back here and run "configure" or choose the appropriate
+zlib/README, then come back here and run "configure" or choose the
-makefile.sys in the scripts directory.
+appropriate makefile in the scripts directory.
 
 VII. Building with makefiles
 
 Copy the file (or files) that you need from the
 scripts directory into this directory, for example
 
-MSDOS example:
-
-    copy scripts\makefile.msc makefile
-    copy scripts\pnglibconf.h.prebuilt pnglibconf.h
-
 UNIX example:
 
-    cp scripts/makefile.std makefile
+    cp scripts/makefile.std Makefile
-    cp scripts/pnglibconf.h.prebuilt pnglibconf.h
+    make
+
+Windows example:
+
+    nmake -f scripts\makefile.vcwin32
 
 Read the makefile to see if you need to change any source or
 target directories to match your preferences.
@@ -190,36 +192,33 @@ test.  For more confidence, you can run another test by typing
 Also, you can run "pngtest -m contrib/pngsuite/*.png" and compare
 your output with the result shown in contrib/pngsuite/README.
 
-Most of the makefiles will allow you to run "make install" to
+Most of the makefiles used to allow you to run "make install" to put
-put the library in its final resting place (if you want to
+the library in its final resting place, but that feature is no longer
-do that, run "make install" in the zlib directory first if necessary).
+supported.  The only tested and supported manners to install libpng are
-Some also allow you to run "make test-installed" after you have
+the conventional build and install procedures driven by the configure
-run "make install".
+script or by the CMake file.
 
-VIII. Configuring libpng for 16-bit platforms
+VIII. Configuring for DOS and other 16-bit platforms
 
-You will want to look into zconf.h to tell zlib (and thus libpng) that
+Officially, the support for 16-bit platforms has been removed.
-it cannot allocate more than 64K at a time.  Even if you can, the memory
-won't be accessible.  So limit zlib and libpng to 64K by defining MAXSEG_64K.
-
-IX. Configuring for DOS
 
 For DOS users who only have access to the lower 640K, you will
 have to limit zlib's memory usage via a png_set_compression_mem_level()
 call.  See zlib.h or zconf.h in the zlib library for more information.
 
-X. Configuring for Medium Model
+You may be or may not be in luck if you target the "large" memory model,
+but all the smaller models ("small", "compact" and "medium") are known
+to be unworkable.  For DOS users who have access beyond the lower 640K,
+a "flat" 32-bit DOS model (such as DJGPP) is strongly recommended.
 
-Libpng's support for medium model has been tested on most of the popular
+For DOS users who only have access to the lower 640K, you will have to
-compilers.  Make sure MAXSEG_64K gets defined, USE_FAR_KEYWORD gets
+limit zlib's memory usage via a png_set_compression_mem_level() call.
-defined, and FAR gets defined to far in pngconf.h, and you should be
+You will also have to look into zconf.h to tell zlib (and thus libpng)
-all set.  Everything in the library (except for zlib's structure) is
+that it cannot allocate more than 64K at a time.  Even if you can, the
-expecting far data.  You must use the typedefs with the p or pp on
+memory won't be accessible.  Therefore, you should limit zlib and libpng
-the end for pointers (or at least look at them and be careful).  Make
+to 64K by defining MAXSEG_64K.
-note that the rows of data are defined as png_bytepp, which is
-an "unsigned char far * far *".
 
-XI. Prepending a prefix to exported symbols
+IX. Prepending a prefix to exported symbols
 
 Starting with libpng-1.6.0, you can configure libpng (when using the
 "configure" script) to prefix all exported symbols by means of the
@@ -230,7 +229,7 @@ identifier).  This creates a set of macros in pnglibconf.h, so this is
 transparent to applications; their function calls get transformed by
 the macros to use the modified names.
 
-XII. Configuring for compiler xxx:
+X. Configuring for compiler xxx:
 
 All includes for libpng are in pngconf.h.  If you need to add, change
 or delete an include, this is the place to do it.
@@ -242,7 +241,7 @@ As of libpng-1.5.0, pngpriv.h also includes three other private header
 files, pngstruct.h, pnginfo.h, and pngdebug.h, which contain material
 that previously appeared in the public headers.
 
-XIII. Removing unwanted object code
+XI. Removing unwanted object code
 
 There are a bunch of #define's in pngconf.h that control what parts of
 libpng are compiled.  All the defines end in _SUPPORTED.  If you are
@@ -281,7 +280,57 @@ library to fail if they call functions not available in your library.
 The size of the library itself should not be an issue, because only
 those sections that are actually used will be loaded into memory.
 
-XIV. Changes to the build and configuration of libpng in libpng-1.5.x
+XII. Enabling or disabling hardware optimizations
+
+Certain hardware capabilities, such as the Intel SSE instructions,
+are normally detected at run time. Enable them with configure options
+such as one of
+
+   --enable-arm-neon=yes
+   --enable-mips-msa=yes
+   --enable-intel-sse=yes
+   --enable-powerpc-vsx=yes
+
+or enable them all at once with
+
+   --enable-hardware-optimizations=yes
+
+or, if you are not using "configure", you can use one
+or more of
+
+   CPPFLAGS += "-DPNG_ARM_NEON"
+   CPPFLAGS += "-DPNG_MIPS_MSA"
+   CPPFLAGS += "-DPNG_INTEL_SSE"
+   CPPFLAGS += "-DPNG_POWERPC_VSX"
+
+See for example scripts/makefile.linux-opt
+
+If you wish to avoid using them,
+you can disable them via the configure option
+
+   --disable-hardware-optimizations
+
+to disable them all, or
+
+   --enable-intel-sse=no
+
+to disable a particular one,
+or via compiler-command options such as
+
+   CPPFLAGS += "-DPNG_ARM_NEON_OPT=0, -DPNG_MIPS_MSA_OPT=0,
+   -DPNG_INTEL_SSE_OPT=0, -DPNG_POWERPC_VSX_OPT=0"
+
+If you are using cmake, hardware optimizations are "on"
+by default. To disable them, use
+
+    cmake . -DPNG_ARM_NEON=no -DPNG_INTEL_SSE=no \
+            -DPNG_MIPS_MSA=no -DPNG_POWERPC_VSX=no
+
+or disable them all at once with
+
+    cmake . -DPNG_HARDWARE_OPTIMIZATIONS=no
+
+XIII. Changes to the build and configuration of libpng in libpng-1.5.x
 
 Details of internal changes to the library code can be found in the CHANGES
 file and in the GIT repository logs.  These will be of no concern to the vast
@@ -372,7 +421,7 @@ $PREFIX/include directory).  Do not edit pnglibconf.h after you have built
 libpng, because than the settings would not accurately reflect the settings
 that were used to build libpng.
 
-XV. Setjmp/longjmp issues
+XIV. Setjmp/longjmp issues
 
 Libpng uses setjmp()/longjmp() for error handling.  Unfortunately setjmp()
 is known to be not thread-safe on some platforms and we don't know of
@@ -390,7 +439,7 @@ This requires setjmp/longjmp, so you must either build the library
 with PNG_SETJMP_SUPPORTED defined, or with PNG_SIMPLIFIED_READ_SUPPORTED
 and PNG_SIMPLIFIED_WRITE_SUPPORTED undefined.
 
-XVI. Common linking failures
+XV. Common linking failures
 
 If your application fails to find libpng or zlib entries while linking:
 
@@ -402,12 +451,13 @@ If your application fails to find libpng or zlib entries while linking:
   If you are using the vstudio project, observe the WARNING in
   project/vstudio/README.txt.
 
-XVII. Other sources of information about libpng:
+XVI. Other sources of information about libpng:
 
 Further information can be found in the README and libpng-manual.txt
 files, in the individual makefiles, in png.h, and the manual pages
 libpng.3 and png.5.
 
+Copyright (c) 2022 Cosmin Truta
 Copyright (c) 1998-2002,2006-2016 Glenn Randers-Pehrson
 This document is released under the libpng license.
 For conditions of distribution and use, see the disclaimer

LICENSE

@@ -1,17 +1,46 @@
+COPYRIGHT NOTICE, DISCLAIMER, and LICENSE
+=========================================
 
-This copy of the libpng notices is provided for your convenience.  In case of
+PNG Reference Library License version 2
-any discrepancy between this copy and the notices in the file png.h that is
+---------------------------------------
-included in the libpng distribution, the latter shall prevail.
 
-COPYRIGHT NOTICE, DISCLAIMER, and LICENSE:
+ * Copyright (c) 1995-2024 The PNG Reference Library Authors.
+ * Copyright (c) 2018-2024 Cosmin Truta.
+ * Copyright (c) 2000-2002, 2004, 2006-2018 Glenn Randers-Pehrson.
+ * Copyright (c) 1996-1997 Andreas Dilger.
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
 
-If you modify libpng you may insert additional notices immediately following
+The software is supplied "as is", without warranty of any kind,
-this sentence.
+express or implied, including, without limitation, the warranties
+of merchantability, fitness for a particular purpose, title, and
+non-infringement.  In no event shall the Copyright owners, or
+anyone distributing the software, be liable for any damages or
+other liability, whether in contract, tort or otherwise, arising
+from, out of, or in connection with the software, or the use or
+other dealings in the software, even if advised of the possibility
+of such damage.
 
-This code is released under the libpng license.
+Permission is hereby granted to use, copy, modify, and distribute
+this software, or portions hereof, for any purpose, without fee,
+subject to the following restrictions:
 
-libpng versions 1.0.7, July 1, 2000 through 1.6.26, October 20, 2016 are
+ 1. The origin of this software must not be misrepresented; you
-Copyright (c) 2000-2002, 2004, 2006-2016 Glenn Randers-Pehrson, are
+    must not claim that you wrote the original software.  If you
+    use this software in a product, an acknowledgment in the product
+    documentation would be appreciated, but is not required.
+
+ 2. Altered source versions must be plainly marked as such, and must
+    not be misrepresented as being the original software.
+
+ 3. This Copyright notice may not be removed or altered from any
+    source or altered source distribution.
+
+
+PNG Reference Library License version 1 (for libpng 0.5 through 1.6.35)
+-----------------------------------------------------------------------
+
+libpng versions 1.0.7, July 1, 2000, through 1.6.35, July 15, 2018 are
+Copyright (c) 2000-2002, 2004, 2006-2018 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:
@@ -22,25 +51,28 @@ 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:
 
-   There is no warranty against interference with your enjoyment of the
+    There is no warranty against interference with your enjoyment of
-   library or against infringement.  There is no warranty that our
+    the library or against infringement.  There is no warranty that our
     efforts or the library will fulfill any of your particular purposes
     or needs.  This library is provided with all faults, and the entire
-   risk of satisfactory quality, performance, accuracy, and effort is with
+    risk of satisfactory quality, performance, accuracy, and effort is
-   the user.
+    with the user.
 
 Some files in the "contrib" directory and some configure-generated
-files that are distributed with libpng have other copyright owners and
+files that are distributed with libpng 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
-license as libpng-0.96, with the following individuals added to the list
+license as libpng-0.96, with the following individuals added to the
-of Contributing Authors:
+list of Contributing Authors:
 
     Tom Lane
     Glenn Randers-Pehrson
@@ -59,7 +91,7 @@ Contributing Authors:
     Greg Roelofs
     Tom Tanner
 
-Some files in the "scripts" directory have other copyright owners
+Some files in the "scripts" directory have other copyright owners,
 but are released under this license.
 
 libpng versions 0.5, May 1995, through 0.88, January 1996, are
@@ -74,13 +106,14 @@ is defined as the following set of individuals:
     Paul Schmidt
     Tim Wegner
 
-The PNG Reference Library is supplied "AS IS".  The Contributing Authors
+The PNG Reference Library is supplied "AS IS".  The Contributing
-and Group 42, Inc. disclaim all warranties, expressed or implied,
+Authors and Group 42, Inc. disclaim all warranties, expressed or
-including, without limitation, the warranties of merchantability and of
+implied, including, without limitation, the warranties of
-fitness for any purpose.  The Contributing Authors and Group 42, Inc.
+merchantability and of fitness for any purpose.  The Contributing
-assume no liability for direct, indirect, incidental, special, exemplary,
+Authors and Group 42, Inc. assume no liability for direct, indirect,
-or consequential damages, which may result from the use of the PNG
+incidental, special, exemplary, or consequential damages, which may
-Reference Library, even if advised of the possibility of such damage.
+result from the use of the PNG Reference Library, even if advised of
+the possibility of such damage.
 
 Permission is hereby granted to use, copy, modify, and distribute this
 source code, or portions hereof, for any purpose, without fee, subject
@@ -94,37 +127,8 @@ to the following restrictions:
  3. This Copyright notice may not be removed or altered from any
     source or altered source distribution.
 
-The Contributing Authors and Group 42, Inc. specifically permit, without
+The Contributing Authors and Group 42, Inc. specifically permit,
-fee, and encourage the use of this source code as a component to
+without fee, and encourage the use of this source code as a component
-supporting the PNG file format in commercial products.  If you use this
+to supporting the PNG file format in commercial products.  If you use
-source code in a product, acknowledgment is not required but would be
+this source code in a product, acknowledgment is not required but would
-appreciated.
+be appreciated.
-
-END OF COPYRIGHT NOTICE, DISCLAIMER, and LICENSE.
-
-TRADEMARK:
-
-The name "libpng" has not been registered by the Copyright owner
-as a trademark in any jurisdiction.  However, because libpng has
-been distributed and maintained world-wide, continually since 1995,
-the Copyright owner claims "common-law trademark protection" in any
-jurisdiction where common-law trademark is recognized.
-
-OSI CERTIFICATION:
-
-Libpng is OSI Certified Open Source Software.  OSI Certified Open Source is
-a certification mark of the Open Source Initiative. OSI has not addressed
-the additional disclaimers inserted at version 1.0.7.
-
-EXPORT CONTROL:
-
-The Copyright owner believes that the Export Control Classification
-Number (ECCN) for libpng is EAR99, which means not subject to export
-controls or International Traffic in Arms Regulations (ITAR) because
-it is open source, publicly available software, that does not contain
-any encryption software.  See the EAR, paragraphs 734.3(b)(3) and
-734.7(b).
-
-Glenn Randers-Pehrson
-glennrp at users.sourceforge.net
-October 20, 2016

Makefile.am

@@ -1,7 +1,7 @@
 # Makefile.am, the source file for Makefile.in (and hence Makefile), is
 #
+# Copyright (c) 2018-2024 Cosmin Truta
 # Copyright (c) 2004-2016 Glenn Randers-Pehrson
-# Last changed in libpng 1.6.25 [October 20, 2016]
 #
 # This code is released under the libpng license.
 # For conditions of distribution and use, see the disclaimer
@@ -9,16 +9,24 @@
 
 PNGLIB_BASENAME= libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@
 
-ACLOCAL_AMFLAGS = -I scripts
+ACLOCAL_AMFLAGS = -I scripts/autoconf
 
 # test programs - run on make check, make distcheck
+if ENABLE_TESTS
 check_PROGRAMS= pngtest pngunknown pngstest pngvalid pngimage pngcp
 if HAVE_CLOCK_GETTIME
 check_PROGRAMS += timepng
 endif
+else
+check_PROGRAMS=
+endif
 
 # Utilities - installed
+if ENABLE_TOOLS
 bin_PROGRAMS= pngfix png-fix-itxt
+else
+bin_PROGRAMS=
+endif
 
 # This ensures that pnglibconf.h gets built at the start of 'make all' or
 # 'make check', but it does not add dependencies to the individual programs,
@@ -30,6 +38,7 @@ bin_PROGRAMS= pngfix png-fix-itxt
 # always wrong and always very confusing.
 BUILT_SOURCES = pnglibconf.h
 
+if ENABLE_TESTS
 pngtest_SOURCES = pngtest.c
 pngtest_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
 
@@ -48,18 +57,22 @@ pngimage_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
 timepng_SOURCES = contrib/libtests/timepng.c
 timepng_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
 
+pngcp_SOURCES = contrib/tools/pngcp.c
+pngcp_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+endif
+
+if ENABLE_TOOLS
 pngfix_SOURCES = contrib/tools/pngfix.c
 pngfix_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
 
 png_fix_itxt_SOURCES = contrib/tools/png-fix-itxt.c
-
+endif
-pngcp_SOURCES = contrib/tools/pngcp.c
-pngcp_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
 
 # Generally these are single line shell scripts to run a test with a particular
 # set of parameters:
+if ENABLE_TESTS
 TESTS =\
-   tests/pngtest\
+   tests/pngtest-all\
    tests/pngvalid-gamma-16-to-8 tests/pngvalid-gamma-alpha-mode\
    tests/pngvalid-gamma-background tests/pngvalid-gamma-expand16-alpha-mode\
    tests/pngvalid-gamma-expand16-background\
@@ -75,6 +88,7 @@ TESTS =\
    tests/pngunknown-discard tests/pngunknown-if-safe tests/pngunknown-sAPI\
    tests/pngunknown-sTER tests/pngunknown-save tests/pngunknown-vpAg\
    tests/pngimage-quick tests/pngimage-full
+endif
 
 # man pages
 dist_man_MANS= libpng.3 libpngpf.3 png.5
@@ -94,7 +108,8 @@ libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES = png.c pngerror.c\
 
 if PNG_ARM_NEON
 libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES += arm/arm_init.c\
-	arm/filter_neon.S arm/filter_neon_intrinsics.c
+	arm/filter_neon.S arm/filter_neon_intrinsics.c \
+	arm/palette_neon_intrinsics.c
 endif
 
 if PNG_MIPS_MSA
@@ -102,6 +117,32 @@ libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES += mips/mips_init.c\
 	mips/filter_msa_intrinsics.c
 endif
 
+if PNG_MIPS_MMI
+if !PNG_MIPS_MSA
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES += mips/mips_init.c
+endif
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES += mips/filter_mmi_inline_assembly.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
+
+if PNG_LOONGARCH_LSX
+noinst_LTLIBRARIES= libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx.la
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la_SOURCES = loongarch/loongarch_lsx_init.c\
+	loongarch/filter_lsx_intrinsics.c
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la_CFLAGS = -mlsx
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LIBADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx.la
+# libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx.la
+endif
+
 nodist_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES = pnglibconf.h
 
 libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LDFLAGS = -no-undefined -export-dynamic \
@@ -122,6 +163,10 @@ else
   libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES = libpng.sym
 endif
 
+if PNG_LOONGARCH_LSX
+  libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES += libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx.la
+endif
+
 #distribute headers in /usr/include/libpng/*
 pkgincludedir= $(includedir)/$(PNGLIB_BASENAME)
 pkginclude_HEADERS= png.h pngconf.h
@@ -136,9 +181,9 @@ pkgconfig_DATA = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.pc
 # from those directories being included.  This only works if the configure is
 # not done in the source directory!
 EXTRA_DIST= \
-	ANNOUNCE CHANGES INSTALL LICENSE README TODO \
+	ANNOUNCE AUTHORS CHANGES INSTALL LICENSE README TODO TRADEMARK \
 	pngtest.png pngbar.png pngnow.png pngbar.jpg autogen.sh \
-	${srcdir}/contrib ${srcdir}/projects ${srcdir}/scripts \
+	${srcdir}/ci ${srcdir}/contrib ${srcdir}/projects ${srcdir}/scripts \
 	$(TESTS) $(XFAIL_TESTS) tests/pngstest \
 	CMakeLists.txt example.c libpng-manual.txt
 

README

@@ -1,56 +1,88 @@
-README for libpng version 1.6.26 - October 20, 2016 (shared library 16.0)
+README for libpng version 1.6.41
-See the note about version numbers near the top of png.h
+================================
 
-See INSTALL for instructions on how to install libpng.
+See the note about version numbers near the top of `png.h`.
+See `INSTALL` for instructions on how to install libpng.
 
-Libpng comes in several distribution formats.  Get libpng-*.tar.gz or
+Libpng comes in several distribution formats.  Get `libpng-*.tar.gz`
-libpng-*.tar.xz or if you want UNIX-style line endings in the text files,
+or `libpng-*.tar.xz` if you want UNIX-style line endings in the text
-or lpng*.7z or lpng*.zip if you want DOS-style line endings.
+files, or `lpng*.7z` or `lpng*.zip` if you want DOS-style line endings.
 
-Version 0.89 was the first official release of libpng.  Don't let the
+For a detailed description on using libpng, read `libpng-manual.txt`.
-fact that it's the first release fool you.  The libpng library has been in
+For examples of libpng in a program, see `example.c` and `pngtest.c`.
-extensive use and testing since mid-1995.  By late 1997 it had
+For usage information and restrictions (what little they are) on libpng,
-finally gotten to the stage where there hadn't been significant
+see `png.h`.  For a description on using zlib (the compression library
-changes to the API in some time, and people have a bad feeling about
+used by libpng) and zlib's restrictions, see `zlib.h`.
-libraries with versions < 1.0.  Version 1.0.0 was released in
-March 1998.
 
-****
+You should use zlib 1.0.4 or later to run this, but it _may_ work with
-Note that some of the changes to the png_info structure render this
+versions as old as zlib 0.95.  Even so, there are bugs in older zlib
+versions which can cause the output of invalid compression streams for
+some images.
+
+You should also note that zlib is a compression library that is useful
+for more things than just PNG files.  You can use zlib as a drop-in
+replacement for `fread()` and `fwrite()`, if you are so inclined.
+
+zlib should be available at the same place that libpng is, or at
+https://zlib.net .
+
+You may also want a copy of the PNG specification.  It is available
+as an RFC, a W3C Recommendation, and an ISO/IEC Standard.  You can find
+these at http://www.libpng.org/pub/png/pngdocs.html .
+
+This code is currently being archived at https://libpng.sourceforge.io
+in the download area, and at http://libpng.download/src .
+
+This release, based in a large way on Glenn's, Guy's and Andreas'
+earlier work, was created and will be supported by myself and the PNG
+development group.
+
+Send comments, corrections and commendations to `png-mng-implement`
+at `lists.sourceforge.net`.  (Subscription is required; visit
+https://lists.sourceforge.net/lists/listinfo/png-mng-implement
+to subscribe.)
+
+Send general questions about the PNG specification to `png-mng-misc`
+at `lists.sourceforge.net`.  (Subscription is required; visit
+https://lists.sourceforge.net/lists/listinfo/png-mng-misc
+to subscribe.)
+
+Historical notes
+----------------
+
+The libpng library has been in extensive use and testing since mid-1995.
+Version 0.89, published a year later, was the first official release.
+By late 1997, it had finally gotten to the stage where there hadn't
+been significant changes to the API in some time, and people have a bad
+feeling about libraries with versions below 1.0.  Version 1.0.0 was
+released in March 1998.
+
+Note that some of the changes to the `png_info` structure render this
 version of the library binary incompatible with libpng-0.89 or
 earlier versions if you are using a shared library.  The type of the
-"filler" parameter for png_set_filler() has changed from png_byte to
+`filler` parameter for `png_set_filler()` has changed from `png_byte`
-png_uint_32, which will affect shared-library applications that use
+to `png_uint_32`, which will affect shared-library applications that
-this function.
+use this function.
 
-To avoid problems with changes to the internals of png info_struct,
+To avoid problems with changes to the internals of the `info_struct`,
 new APIs have been made available in 0.95 to avoid direct application
-access to info_ptr.  These functions are the png_set_<chunk> and
+access to `info_ptr`.  These functions are the `png_set_<chunk>` and
-png_get_<chunk> functions.  These functions should be used when
+`png_get_<chunk>` functions.  These functions should be used when
-accessing/storing the info_struct data, rather than manipulating it
+accessing/storing the `info_struct` data, rather than manipulating it
 directly, to avoid such problems in the future.
 
 It is important to note that the APIs did not make current programs
 that access the info struct directly incompatible with the new
 library, through libpng-1.2.x.  In libpng-1.4.x, which was meant to
-be a transitional release, members of the png_struct and the
+be a transitional release, members of the `png_struct` and the
-info_struct can still be accessed, but the compiler will issue a
+`info_struct` can still be accessed, but the compiler will issue a
 warning about deprecated usage.  Since libpng-1.5.0, direct access
 to these structs is not allowed, and the definitions of the structs
-reside in private pngstruct.h and pnginfo.h header files that are not
+reside in private `pngstruct.h` and `pnginfo.h` header files that are
-accessible to applications.  It is strongly suggested that new
+not accessible to applications.  It is strongly suggested that new
-programs use the new APIs (as shown in example.c and pngtest.c), and
+programs use the new APIs (as shown in `example.c` and `pngtest.c`),
-older programs be converted to the new format, to facilitate upgrades
+and older programs be converted to the new format, to facilitate
-in the future.
+upgrades in the future.
-****
-
-Additions since 0.90 include the ability to compile libpng as a
-Windows DLL, and new APIs for accessing data in the info struct.
-Experimental functions include the ability to set weighting and cost
-factors for row filter selection, direct reads of integers from buffers
-on big-endian processors that support misaligned data access, faster
-methods of doing alpha composition, and more accurate 16->8 bit color
-conversion.
 
 The additions since 0.89 include the ability to read from a PNG stream
 which has had some (or all) of the signature bytes read by the calling
@@ -60,99 +92,31 @@ the library action on the detection of chunk CRC errors.  It is possible
 to set different actions based on whether the CRC error occurred in a
 critical or an ancillary chunk.
 
-The changes made to the library, and bugs fixed are based on discussions
+The additions since 0.90 include the ability to compile libpng as a
-on the PNG-implement mailing list and not on material submitted
+Windows DLL, and new APIs for accessing data in the `info_struct`.
-privately to Guy, Andreas, or Glenn.  They will forward any good
+Experimental functions included the ability to set weighting and cost
-suggestions to the list.
+factors for row filter selection, direct reads of integers from buffers
+on big-endian processors that support misaligned data access, faster
+methods of doing alpha composition, and more accurate 16-to-8 bit color
+conversion.  Some of these experimental functions, such as the weighted
+filter heuristics, have since been removed.
 
-For a detailed description on using libpng, read libpng-manual.txt.  For
+Files included in this distribution
-examples of libpng in a program, see example.c and pngtest.c.  For usage
+-----------------------------------
-information and restrictions (what little they are) on libpng, see
-png.h.  For a description on using zlib (the compression library used by
-libpng) and zlib's restrictions, see zlib.h
-
-I have included a general makefile, as well as several machine and
-compiler specific ones, but you may have to modify one for your own needs.
-
-You should use zlib 1.0.4 or later to run this, but it MAY work with
-versions as old as zlib 0.95.  Even so, there are bugs in older zlib
-versions which can cause the output of invalid compression streams for
-some images.  You will definitely need zlib 1.0.4 or later if you are
-taking advantage of the MS-DOS "far" structure allocation for the small
-and medium memory models.  You should also note that zlib is a
-compression library that is useful for more things than just PNG files.
-You can use zlib as a drop-in replacement for fread() and fwrite() if
-you are so inclined.
-
-zlib should be available at the same place that libpng is, or at zlib.net.
-
-You may also want a copy of the PNG specification.  It is available
-as an RFC, a W3C Recommendation, and an ISO/IEC Standard.  You can find
-these at http://www.libpng.org/pub/png/documents/
-
-This code is currently being archived at libpng.sf.net in the
-[DOWNLOAD] area, and at ftp://ftp.simplesystems.org.  If you can't find it
-in any of those places, e-mail me, and I'll help you find it.
-
-I am not a lawyer, but I believe that the Export Control Classification
-Number (ECCN) for libpng is EAR99, which means not subject to export
-controls or International Traffic in Arms Regulations (ITAR) because it
-is open source, publicly available software, that does not contain any
-encryption software.  See the EAR, paragraphs 734.3(b)(3) and 734.7(b).
-
-If you have any code changes, requests, problems, etc., please e-mail
-them to me.  Also, I'd appreciate any make files or project files,
-and any modifications you needed to make to get libpng to compile,
-along with a #define variable to tell what compiler/system you are on.
-If you needed to add transformations to libpng, or wish libpng would
-provide the image in a different way, drop me a note (and code, if
-possible), so I can consider supporting the transformation.
-Finally, if you get any warning messages when compiling libpng
-(note: not zlib), and they are easy to fix, I'd appreciate the
-fix.  Please mention "libpng" somewhere in the subject line.  Thanks.
-
-This release was created and will be supported by myself (of course
-based in a large way on Guy's and Andreas' earlier work), and the PNG
-development group.
-
-Send comments/corrections/commendations to png-mng-implement at
-lists.sourceforge.net (subscription required; visit
-https://lists.sourceforge.net/lists/listinfo/png-mng-implement
-to subscribe) or to glennrp at users.sourceforge.net
-
-You can't reach Guy, the original libpng author, at the addresses
-given in previous versions of this document.  He and Andreas will
-read mail addressed to the png-implement list, however.
-
-Please do not send general questions about PNG.  Send them to
-png-mng-misc at lists.sf.net (subscription required; visit
-https://lists.sourceforge.net/lists/listinfo/png-mng-misc to
-subscribe).  If you have a question about something
-in the PNG specification that is related to using libpng, send it
-to me.  Send me any questions that start with "I was using libpng,
-and ...".  If in doubt, send questions to me.  I'll bounce them
-to others, if necessary.
-
-Please do not send suggestions on how to change PNG.  We have
-been discussing PNG for twenty years now, and it is official and
-finished.  If you have suggestions for libpng, however, I'll
-gladly listen.  Even if your suggestion is not used immediately,
-it may be used later.
-
-Files in this distribution:
 
     ANNOUNCE      =>  Announcement of this version, with recent changes
+    AUTHORS       =>  List of contributing authors
     CHANGES       =>  Description of changes between libpng versions
-      KNOWNBUG      =>  List of known bugs and deficiencies
+    INSTALL       =>  Instructions to install libpng
     LICENSE       =>  License to use and redistribute libpng
     README        =>  This file
     TODO          =>  Things not implemented in the current library
-      Y2KINFO       =>  Statement of Y2K compliance
+    TRADEMARK     =>  Trademark information
     example.c     =>  Example code for using libpng functions
-      libpng.3      =>  manual page for libpng (includes libpng-manual.txt)
+    libpng.3      =>  Manual page for libpng (includes libpng-manual.txt)
     libpng-manual.txt  =>  Description of libpng and its functions
-      libpngpf.3    =>  manual page for libpng's private functions
+    libpngpf.3    =>  Manual page for libpng's private functions (deprecated)
-      png.5         =>  manual page for the PNG format
+    png.5         =>  Manual page for the PNG format
     png.c         =>  Basic interface functions common to library
     png.h         =>  Library function and interface declarations (public)
     pngpriv.h     =>  Library function and interface declarations (private)
@@ -178,41 +142,41 @@ Files in this distribution:
     pngwrite.c    =>  High-level write functions
     pngwtran.c    =>  Write data transformations
     pngwutil.c    =>  Write utility functions
-      arm           =>  Contains optimized code for the ARM platform
+    arm/          =>  Optimized code for the ARM platform
-      contrib       =>  Contributions
+    intel/        =>  Optimized code for the INTEL-SSE2 platform
-       arm-neon         =>  Optimized code for ARM-NEON platform
+    mips/         =>  Optimized code for the MIPS platform
-       examples         =>  Example programs
+    powerpc/      =>  Optimized code for the PowerPC platform
-       gregbook         =>  source code for PNG reading and writing, from
+    ci/           =>  Scripts for continuous integration
-                            Greg Roelofs' "PNG: The Definitive Guide",
+    contrib/      =>  External contributions
+        arm-neon/     =>  Optimized code for the ARM-NEON platform
+        mips-msa/     =>  Optimized code for the MIPS-MSA platform
+        powerpc-vsx/  =>  Optimized code for the POWERPC-VSX platform
+        examples/     =>  Examples of libpng usage
+        gregbook/     =>  Source code for PNG reading and writing, from
+                          "PNG: The Definitive Guide" by Greg Roelofs,
                           O'Reilly, 1999
-       intel            =>  Optimized code for INTEL-SSE2 platform
+        libtests/     =>  Test programs
-       libtests         =>  Test programs
+        oss-fuzz/     =>  Files used by the OSS-Fuzz project for fuzz-testing
-       pngminim         =>  Minimal decoder, encoder, and progressive decoder
+                          libpng
-                            programs demonstrating use of pngusr.dfa
+        pngminim/     =>  Minimal decoder, encoder, and progressive decoder
-       pngminus         =>  Simple pnm2png and png2pnm programs
+                          programs demonstrating the use of pngusr.dfa
-       pngsuite         =>  Test images
+        pngminus/     =>  Simple pnm2png and png2pnm programs
-       testpngs
+        pngsuite/     =>  Test images
-       tools            =>  Various tools
+        testpngs/     =>  Test images
-       visupng          =>  Contains a MSVC workspace for VisualPng
+        tools/        =>  Various tools
-      projects      =>  Contains project files and workspaces for
+        visupng/      =>  VisualPng, a Windows viewer for PNG images
-                        building a DLL
+    projects/     =>  Project files and workspaces for various IDEs
-       owatcom          =>  Contains a WATCOM project for building libpng
+        owatcom/      =>  OpenWatcom project
-       visualc71        =>  Contains a Microsoft Visual C++ (MSVC)
+        visualc71/    =>  Microsoft Visual C++ 7.1 workspace
-                            workspace for building libpng and zlib
+        vstudio/      =>  Microsoft Visual Studio workspace
-       vstudio          =>  Contains a Microsoft Visual C++ (MSVC)
+    scripts/      =>  Scripts and makefiles for building libpng
-                            workspace for building libpng and zlib
+                      (see scripts/README.txt for the complete list)
-      scripts       =>  Directory containing scripts for building libpng:
+    tests/        =>  Test scripts
-                            (see scripts/README.txt for the list of scripts)
 
-Good luck, and happy coding.
+Good luck, and happy coding!
 
--Glenn Randers-Pehrson (current maintainer, since 1998)
+ * Cosmin Truta (current maintainer, since 2018)
- Internet: glennrp at users.sourceforge.net
+ * Glenn Randers-Pehrson (former maintainer, 1998-2018)
-
+ * Andreas Eric Dilger (former maintainer, 1996-1997)
--Andreas Eric Dilger (former maintainer, 1996-1997)
+ * Guy Eric Schalnat (original author and former maintainer, 1995-1996)
- Internet: adilger at enel.ucalgary.ca
+   (formerly of Group 42, Inc.)
- Web: http://www-mddsp.enel.ucalgary.ca/People/adilger/
-
--Guy Eric Schalnat (original author and former maintainer, 1995-1996)
- (formerly of Group 42, Inc)
- Internet: gschal at infinet.com

TODO

@@ -1,30 +1,23 @@
-/*
 TODO - list of things to do for libpng:
 
-Final bug fixes.
+* Fix all defects (duh!)
-Better C++ wrapper/full C++ implementation?
+* Better C++ wrapper / full C++ implementation (?)
-Fix problem with C++ and EXTERN "C".
+* Fix the problems with C++ and 'extern "C"'.
-cHRM transformation.
+* cHRM transformation.
-Remove setjmp/longjmp usage in favor of returning error codes. As a start on
+* Palette creation.
-  this, minimize the use of png_error(), replacing them with
+* "grayscale->palette" transformation and "palette->grayscale" detection.
-  png_warning(); return(0; or similar.
+* Improved dithering.
-Palette creation.
+* Multi-lingual error and warning message support.
-Add "grayscale->palette" transformation and "palette->grayscale" detection.
+* Complete sRGB transformation.  (Currently it simply uses gamma=0.45455.)
-Improved dithering.
+* Man pages for function calls.
-Multi-lingual error and warning message support.
+* Better documentation.
-Complete sRGB transformation (presently it simply uses gamma=0.45455).
+* Better filter selection
-Man pages for function calls.
+  (e.g., counting huffman bits/precompression; filter inertia; filter costs).
-Better documentation.
+* Histogram creation.
-Better filter selection
+* Text conversion between different code pages (e.g., Latin-1 -> Mac).
-   (counting huffman bits/precompression?  filter inertia?  filter costs?).
+* Avoid building gamma tables whenever possible.
-Histogram creation.
+* Greater precision in changing to linear gamma for compositing against
-Text conversion between different code pages (Latin-1 -> Mac and DOS).
+  background, and in doing rgb-to-gray transformations.
-Avoid building gamma tables whenever possible.
+* Investigate pre-incremented loop counters and other loop constructions.
-Use greater precision when changing to linear gamma for compositing against
+* Interpolated method of handling interlacing.
-  background and doing rgb-to-gray transformation.
+* More validations for libpng transformations.
-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.
-
-*/

TRADEMARK

@@ -0,0 +1,8 @@
+TRADEMARK
+=========
+
+The name "libpng" has not been registered by the Copyright owners
+as a trademark in any jurisdiction.  However, because libpng has
+been distributed and maintained world-wide, continually since 1995,
+the Copyright owners claim "common-law trademark protection" in any
+jurisdiction where common-law trademark is recognized.

arm/arm_init.c

@@ -1,17 +1,16 @@
 
 /* arm_init.c - NEON optimised filter functions
  *
+ * Copyright (c) 2018-2022 Cosmin Truta
  * Copyright (c) 2014,2016 Glenn Randers-Pehrson
  * Written by Mans Rullgard, 2011.
- * 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
  */
-/* Below, after checking __linux__, various non-C90 POSIX 1003.1 functions are
+
- * called.
+/* This module requires POSIX 1003.1 functions. */
- */
 #define _POSIX_SOURCE 1
 
 #include "../pngpriv.h"
@@ -32,21 +31,26 @@
  * has partial support is contrib/arm-neon/linux.c - a generic Linux
  * implementation which reads /proc/cpufino.
  */
+#include <signal.h> /* for sig_atomic_t */
+
 #ifndef PNG_ARM_NEON_FILE
-#  ifdef __linux__
+#  if defined(__aarch64__) || defined(_M_ARM64)
+     /* ARM Neon is expected to be unconditionally available on ARM64. */
+#    error "PNG_ARM_NEON_CHECK_SUPPORTED must not be defined on ARM64"
+#  elif defined(__ARM_NEON__) || defined(__ARM_NEON)
+     /* ARM Neon is expected to be available on the target CPU architecture. */
+#    error "PNG_ARM_NEON_CHECK_SUPPORTED must not be defined on this CPU arch"
+#  elif defined(__linux__)
 #    define PNG_ARM_NEON_FILE "contrib/arm-neon/linux.c"
+#  else
+#    error "No support for run-time ARM Neon checking; use compile-time options"
 #  endif
 #endif
 
-#ifdef PNG_ARM_NEON_FILE
-
-#include <signal.h> /* for sig_atomic_t */
 static int png_have_neon(png_structp png_ptr);
-#include PNG_ARM_NEON_FILE
+#ifdef PNG_ARM_NEON_FILE
-
+#  include PNG_ARM_NEON_FILE
-#else  /* PNG_ARM_NEON_FILE */
+#endif
-#  error "PNG_ARM_NEON_FILE undefined: no support for run-time ARM NEON checks"
-#endif /* PNG_ARM_NEON_FILE */
 #endif /* PNG_ARM_NEON_CHECK_SUPPORTED */
 
 #ifndef PNG_ALIGNED_MEMORY_SUPPORTED

arm/filter_neon.S

@@ -1,9 +1,9 @@
 
 /* filter_neon.S - NEON optimised filter functions
  *
- * Copyright (c) 2014 Glenn Randers-Pehrson
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 2014,2017 Glenn Randers-Pehrson
  * Written by Mans Rullgard, 2011.
- * Last changed in libpng 1.6.16 [December 22, 2014]
  *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
@@ -16,7 +16,7 @@
 #define PNG_VERSION_INFO_ONLY
 #include "../pngpriv.h"
 
-#if defined(__linux__) && defined(__ELF__)
+#if (defined(__linux__) || defined(__FreeBSD__)) && defined(__ELF__)
 .section .note.GNU-stack,"",%progbits /* mark stack as non-executable */
 #endif
 

arm/filter_neon_intrinsics.c

@@ -1,12 +1,11 @@
 
 /* filter_neon_intrinsics.c - NEON optimised filter functions
  *
+ * Copyright (c) 2018 Cosmin Truta
  * Copyright (c) 2014,2016 Glenn Randers-Pehrson
  * Written by James Yu <james.yu at linaro.org>, October 2013.
  * Based on filter_neon.S, written by Mans Rullgard, 2011.
  *
- * Last changed in libpng 1.6.22 [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
@@ -19,7 +18,11 @@
 /* This code requires -mfpu=neon on the command line: */
 #if PNG_ARM_NEON_IMPLEMENTATION == 1 /* intrinsics code from pngpriv.h */
 
-#include <arm_neon.h>
+#if defined(_MSC_VER) && !defined(__clang__) && defined(_M_ARM64)
+#  include <arm64_neon.h>
+#else
+#  include <arm_neon.h>
+#endif
 
 /* libpng row pointers are not necessarily aligned to any particular boundary,
  * however this code will only work with appropriate alignment.  arm/arm_init.c
@@ -33,6 +36,11 @@
  * 'type'.  This is written this way just to hide the GCC strict aliasing
  * warning; note that the code is safe because there never is an alias between
  * the input and output pointers.
+ *
+ * When compiling with MSVC ARM64, the png_ldr macro can't be passed directly
+ * to vst4_lane_u32, because of an internal compiler error inside MSVC.
+ * To avoid this compiler bug, we use a temporary variable (vdest_val) to store
+ * the result of png_ldr.
  */
 #define png_ldr(type,pointer)\
    (temp_pointer = png_ptr(type,pointer), *temp_pointer)
@@ -125,12 +133,15 @@ png_read_filter_row_sub4_neon(png_row_infop row_info, png_bytep row,
       uint8x8x4_t *vrpt = png_ptr(uint8x8x4_t,&vtmp);
       uint8x8x4_t vrp = *vrpt;
       uint32x2x4_t *temp_pointer;
+      uint32x2x4_t vdest_val;
 
       vdest.val[0] = vadd_u8(vdest.val[3], vrp.val[0]);
       vdest.val[1] = vadd_u8(vdest.val[0], vrp.val[1]);
       vdest.val[2] = vadd_u8(vdest.val[1], vrp.val[2]);
       vdest.val[3] = vadd_u8(vdest.val[2], vrp.val[3]);
-      vst4_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2x4_t,&vdest), 0);
+
+      vdest_val = png_ldr(uint32x2x4_t, &vdest);
+      vst4_lane_u32(png_ptr(uint32_t,rp), vdest_val, 0);
    }
 
    PNG_UNUSED(prev_row)
@@ -223,6 +234,7 @@ png_read_filter_row_avg4_neon(png_row_infop row_info, png_bytep row,
       uint8x8x4_t *vrpt, *vppt;
       uint8x8x4_t vrp, vpp;
       uint32x2x4_t *temp_pointer;
+      uint32x2x4_t vdest_val;
 
       vtmp = vld4_u32(png_ptr(uint32_t,rp));
       vrpt = png_ptr(uint8x8x4_t,&vtmp);
@@ -240,7 +252,8 @@ png_read_filter_row_avg4_neon(png_row_infop row_info, png_bytep row,
       vdest.val[3] = vhadd_u8(vdest.val[2], vpp.val[3]);
       vdest.val[3] = vadd_u8(vdest.val[3], vrp.val[3]);
 
-      vst4_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2x4_t,&vdest), 0);
+      vdest_val = png_ldr(uint32x2x4_t, &vdest);
+      vst4_lane_u32(png_ptr(uint32_t,rp), vdest_val, 0);
    }
 }
 
@@ -359,6 +372,7 @@ png_read_filter_row_paeth4_neon(png_row_infop row_info, png_bytep row,
       uint8x8x4_t *vrpt, *vppt;
       uint8x8x4_t vrp, vpp;
       uint32x2x4_t *temp_pointer;
+      uint32x2x4_t vdest_val;
 
       vtmp = vld4_u32(png_ptr(uint32_t,rp));
       vrpt = png_ptr(uint8x8x4_t,&vtmp);
@@ -378,7 +392,8 @@ png_read_filter_row_paeth4_neon(png_row_infop row_info, png_bytep row,
 
       vlast = vpp.val[3];
 
-      vst4_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2x4_t,&vdest), 0);
+      vdest_val = png_ldr(uint32x2x4_t, &vdest);
+      vst4_lane_u32(png_ptr(uint32_t,rp), vdest_val, 0);
    }
 }
 

arm/palette_neon_intrinsics.c

@@ -0,0 +1,151 @@
+
+/* palette_neon_intrinsics.c - NEON optimised palette expansion functions
+ *
+ * Copyright (c) 2018-2019 Cosmin Truta
+ * Copyright (c) 2017-2018 Arm Holdings. All rights reserved.
+ * Written by Richard Townsend <Richard.Townsend@arm.com>, February 2017.
+ *
+ * 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"
+
+#if PNG_ARM_NEON_IMPLEMENTATION == 1
+
+#if defined(_MSC_VER) && !defined(__clang__) && defined(_M_ARM64)
+#  include <arm64_neon.h>
+#else
+#  include <arm_neon.h>
+#endif
+
+/* Build an RGBA8 palette from the separate RGB and alpha palettes. */
+void
+png_riffle_palette_neon(png_structrp png_ptr)
+{
+   png_const_colorp palette = png_ptr->palette;
+   png_bytep riffled_palette = png_ptr->riffled_palette;
+   png_const_bytep trans_alpha = png_ptr->trans_alpha;
+   int num_trans = png_ptr->num_trans;
+   int i;
+
+   /* Initially black, opaque. */
+   uint8x16x4_t w = {{
+      vdupq_n_u8(0x00),
+      vdupq_n_u8(0x00),
+      vdupq_n_u8(0x00),
+      vdupq_n_u8(0xff),
+   }};
+
+   png_debug(1, "in png_riffle_palette_neon");
+
+   /* First, riffle the RGB colours into an RGBA8 palette.
+    * The alpha component is set to opaque for now.
+    */
+   for (i = 0; i < 256; i += 16)
+   {
+      uint8x16x3_t v = vld3q_u8((png_const_bytep)(palette + i));
+      w.val[0] = v.val[0];
+      w.val[1] = v.val[1];
+      w.val[2] = v.val[2];
+      vst4q_u8(riffled_palette + (i << 2), w);
+   }
+
+   /* Fix up the missing transparency values. */
+   for (i = 0; i < num_trans; i++)
+      riffled_palette[(i << 2) + 3] = trans_alpha[i];
+}
+
+/* Expands a palettized row into RGBA8. */
+int
+png_do_expand_palette_rgba8_neon(png_structrp png_ptr, png_row_infop row_info,
+    png_const_bytep row, png_bytepp ssp, png_bytepp ddp)
+{
+   png_uint_32 row_width = row_info->width;
+   const png_uint_32 *riffled_palette =
+      (const png_uint_32 *)png_ptr->riffled_palette;
+   const png_uint_32 pixels_per_chunk = 4;
+   png_uint_32 i;
+
+   png_debug(1, "in png_do_expand_palette_rgba8_neon");
+
+   PNG_UNUSED(row)
+   if (row_width < pixels_per_chunk)
+      return 0;
+
+   /* This function originally gets the last byte of the output row.
+    * The NEON part writes forward from a given position, so we have
+    * to seek this back by 4 pixels x 4 bytes.
+    */
+   *ddp = *ddp - ((pixels_per_chunk * sizeof(png_uint_32)) - 1);
+
+   for (i = 0; i < row_width; i += pixels_per_chunk)
+   {
+      uint32x4_t cur;
+      png_bytep sp = *ssp - i, dp = *ddp - (i << 2);
+      cur = vld1q_dup_u32 (riffled_palette + *(sp - 3));
+      cur = vld1q_lane_u32(riffled_palette + *(sp - 2), cur, 1);
+      cur = vld1q_lane_u32(riffled_palette + *(sp - 1), cur, 2);
+      cur = vld1q_lane_u32(riffled_palette + *(sp - 0), cur, 3);
+      vst1q_u32((void *)dp, cur);
+   }
+   if (i != row_width)
+   {
+      /* Remove the amount that wasn't processed. */
+      i -= pixels_per_chunk;
+   }
+
+   /* Decrement output pointers. */
+   *ssp = *ssp - i;
+   *ddp = *ddp - (i << 2);
+   return i;
+}
+
+/* Expands a palettized row into RGB8. */
+int
+png_do_expand_palette_rgb8_neon(png_structrp png_ptr, png_row_infop row_info,
+    png_const_bytep row, png_bytepp ssp, png_bytepp ddp)
+{
+   png_uint_32 row_width = row_info->width;
+   png_const_bytep palette = (png_const_bytep)png_ptr->palette;
+   const png_uint_32 pixels_per_chunk = 8;
+   png_uint_32 i;
+
+   png_debug(1, "in png_do_expand_palette_rgb8_neon");
+
+   PNG_UNUSED(row)
+   if (row_width <= pixels_per_chunk)
+      return 0;
+
+   /* Seeking this back by 8 pixels x 3 bytes. */
+   *ddp = *ddp - ((pixels_per_chunk * sizeof(png_color)) - 1);
+
+   for (i = 0; i < row_width; i += pixels_per_chunk)
+   {
+      uint8x8x3_t cur;
+      png_bytep sp = *ssp - i, dp = *ddp - ((i << 1) + i);
+      cur = vld3_dup_u8(palette + sizeof(png_color) * (*(sp - 7)));
+      cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 6)), cur, 1);
+      cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 5)), cur, 2);
+      cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 4)), cur, 3);
+      cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 3)), cur, 4);
+      cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 2)), cur, 5);
+      cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 1)), cur, 6);
+      cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 0)), cur, 7);
+      vst3_u8((void *)dp, cur);
+   }
+
+   if (i != row_width)
+   {
+      /* Remove the amount that wasn't processed. */
+      i -= pixels_per_chunk;
+   }
+
+   /* Decrement output pointers. */
+   *ssp = *ssp - i;
+   *ddp = *ddp - ((i << 1) + i);
+   return i;
+}
+
+#endif /* PNG_ARM_NEON_IMPLEMENTATION */

autogen.sh

@@ -77,13 +77,14 @@ libpng_autotools_files="Makefile.in aclocal.m4 config.guess config.h.in
    config.sub configure depcomp install-sh ltmain.sh missing\
    test-driver"
 #
-# Files generated by versions of configue >2.68 or automake >1.13 (i.e. later
+# Files generated by versions of autoconf >2.68 or automake >1.13 (i.e. later
 # versions than those required by configure.ac):
 libpng_autotools_extra="compile config.h.in~"
 #
 # These are separate because 'maintainer-clean' does not remove them.
-libpng_libtool_files="scripts/libtool.m4 scripts/ltoptions.m4\
+libpng_libtool_files="scripts/autoconf/libtool.m4 scripts/autoconf/ltoptions.m4\
-   scripts/ltsugar.m4 scripts/ltversion.m4 scripts/lt~obsolete.m4"
+   scripts/autoconf/ltsugar.m4 scripts/autoconf/ltversion.m4\
+   scripts/autoconf/lt~obsolete.m4"
 
 libpng_autotools_dirs="autom4te.cache" # not required
 #
@@ -194,7 +195,7 @@ case "$mode" in
       if test -d .git
       then
          exec >&2
-         echo "ERROR: running autoreconf on an initialized sytem"
+         echo "ERROR: running autoreconf on an initialized system"
          echo "  This is not necessary; it is only necessary to remake the"
          echo "  autotools generated files if Makefile.am or configure.ac"
          echo "  change and make does the right thing with:"

ci/.shellcheckrc

@@ -0,0 +1,11 @@
+# Disable the "variable appears unused" warning caused by the use of getopts
+# with an obligatory (but unused) variable name in the main function.
+disable=SC2034
+
+# Disable all the "quote to prevent globbing or word splitting" advice.
+# We need word splitting for well-known variables like MAKEFLAGS and CFLAGS.
+disable=SC2086,SC2206
+
+# Disable the "possible misspelling" warnings that might be flagged, e.g.,
+# inside function ci_trace_build.
+disable=SC2153

ci/LICENSE_MIT.txt

@@ -0,0 +1,19 @@
+MIT License
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

ci/ci_lint_ci.sh

@@ -0,0 +1,88 @@
+#!/usr/bin/env bash
+set -e
+
+# Copyright (c) 2019-2024 Cosmin Truta.
+#
+# Use, modification and distribution are subject to the MIT License.
+# Please see the accompanying file LICENSE_MIT.txt
+#
+# SPDX-License-Identifier: MIT
+
+# shellcheck source="ci/lib/ci.lib.sh"
+source "$(dirname "$0")/lib/ci.lib.sh"
+cd "$CI_TOPLEVEL_DIR"
+
+CI_SHELLCHECK="$(command -v shellcheck || true)"
+CI_YAMLLINT="$(command -v yamllint || true)"
+CI_LINT_COUNTER=0
+
+function ci_lint_ci_config_files {
+    ci_info "linting: CI config files"
+    local MY_FILE
+    if [[ -x $CI_YAMLLINT ]]
+    then
+        ci_spawn "$CI_YAMLLINT" --version
+        for MY_FILE in "$CI_TOPLEVEL_DIR"/.*.yml
+        do
+            ci_spawn "$CI_YAMLLINT" --strict "$MY_FILE" ||
+                CI_LINT_COUNTER=$((CI_LINT_COUNTER + 1))
+        done
+    else
+        ci_warn "program not found: 'yamllint'; skipping checks"
+    fi
+}
+
+function ci_lint_ci_scripts {
+    ci_info "linting: CI scripts"
+    local MY_FILE
+    if [[ -x $CI_SHELLCHECK ]]
+    then
+        ci_spawn "$CI_SHELLCHECK" --version
+        for MY_FILE in "$CI_SCRIPT_DIR"/*.sh
+        do
+            ci_spawn "$CI_SHELLCHECK" -x "$MY_FILE" ||
+                CI_LINT_COUNTER=$((CI_LINT_COUNTER + 1))
+        done
+    else
+        ci_warn "program not found: 'shellcheck'; skipping checks"
+    fi
+}
+
+function ci_lint_ci_scripts_license {
+    ci_info "linting: CI scripts license"
+    ci_spawn grep -F "MIT License" ci/LICENSE_MIT.txt || {
+        ci_warn "bad or missing CI license file: '$CI_SCRIPT_DIR/LICENSE_MIT.txt'"
+        CI_LINT_COUNTER=$((CI_LINT_COUNTER + 1))
+    }
+}
+
+function usage {
+    echo "usage: $CI_SCRIPT_NAME"
+    exit 0
+}
+
+function main {
+    local opt
+    while getopts ":" opt
+    do
+        # This ain't a while-loop. It only pretends to be.
+        [[ $1 == -[?h]* || $1 == --help ]] && usage
+        ci_err "unknown option: '$1'"
+    done
+    shift $((OPTIND - 1))
+    # And... go!
+    [[ $# -eq 0 ]] || ci_err "unexpected argument: '$1'"
+    ci_lint_ci_config_files
+    ci_lint_ci_scripts
+    ci_lint_ci_scripts_license
+    if [[ $CI_LINT_COUNTER -eq 0 ]]
+    then
+        ci_info "success!"
+        exit 0
+    else
+        ci_info "failed on $CI_LINT_COUNTER file(s)"
+        exit 1
+    fi
+}
+
+main "$@"

ci/ci_verify_cmake.sh

@@ -0,0 +1,194 @@
+#!/usr/bin/env bash
+set -e
+
+# Copyright (c) 2019-2024 Cosmin Truta.
+#
+# Use, modification and distribution are subject to the MIT License.
+# Please see the accompanying file LICENSE_MIT.txt
+#
+# SPDX-License-Identifier: MIT
+
+# shellcheck source="ci/lib/ci.lib.sh"
+source "$(dirname "$0")/lib/ci.lib.sh"
+cd "$CI_TOPLEVEL_DIR"
+
+CI_SRC_DIR="$CI_TOPLEVEL_DIR"
+CI_OUT_DIR="$CI_TOPLEVEL_DIR/out"
+CI_BUILD_DIR="$CI_OUT_DIR/ci_verify_cmake.$CI_TARGET_SYSTEM.$CI_TARGET_ARCH.build"
+CI_INSTALL_DIR="$CI_OUT_DIR/ci_verify_cmake.$CI_TARGET_SYSTEM.$CI_TARGET_ARCH.install"
+
+# Keep the following relative paths in sync with the absolute paths.
+# We use them for the benefit of native Windows tools that might be
+# otherwise confused by the path encoding used by Bash-on-Windows.
+CI_BUILD_TO_SRC_RELDIR="../.."
+CI_BUILD_TO_INSTALL_RELDIR="../ci_verify_cmake.$CI_TARGET_SYSTEM.$CI_TARGET_ARCH.install"
+
+function ci_init_build {
+    # Ensure that the mandatory variables are initialized.
+    CI_CMAKE="${CI_CMAKE:-cmake}"
+    CI_CTEST="${CI_CTEST:-ctest}"
+    CI_CMAKE_BUILD_TYPE="${CI_CMAKE_BUILD_TYPE:-Release}"
+    [[ -x $(command -v ninja) ]] &&
+        CI_CMAKE_GENERATOR="${CI_CMAKE_GENERATOR:-Ninja}"
+    if [[ $CI_CMAKE_GENERATOR == "Visual Studio"* ]]
+    then
+        # Clean up incidental mixtures of Windows and Bash-on-Windows
+        # environment variables, to avoid confusing MSBuild.
+        [[ $TEMP && ( $Temp || $temp ) ]] && unset TEMP
+        [[ $TMP && ( $Tmp || $tmp ) ]] && unset TMP
+        # Ensure that CI_CMAKE_GENERATOR_PLATFORM is initialized for this generator.
+        [[ $CI_CMAKE_GENERATOR_PLATFORM ]] ||
+            ci_err_internal "missing \$CI_CMAKE_GENERATOR_PLATFORM"
+    fi
+}
+
+function ci_trace_build {
+    ci_info "## START OF CONFIGURATION ##"
+    ci_info "build arch: $CI_BUILD_ARCH"
+    ci_info "build system: $CI_BUILD_SYSTEM"
+    [[ "$CI_TARGET_SYSTEM.$CI_TARGET_ARCH" != "$CI_BUILD_SYSTEM.$CI_BUILD_ARCH" ]] && {
+        ci_info "target arch: $CI_TARGET_ARCH"
+        ci_info "target system: $CI_TARGET_SYSTEM"
+    }
+    ci_info "source directory: $CI_SRC_DIR"
+    ci_info "build directory: $CI_BUILD_DIR"
+    ci_info "install directory: $CI_INSTALL_DIR"
+    ci_info "environment option: \$CI_CMAKE: '$CI_CMAKE'"
+    ci_info "environment option: \$CI_CMAKE_GENERATOR: '$CI_CMAKE_GENERATOR'"
+    ci_info "environment option: \$CI_CMAKE_GENERATOR_PLATFORM: '$CI_CMAKE_GENERATOR_PLATFORM'"
+    ci_info "environment option: \$CI_CMAKE_BUILD_TYPE: '$CI_CMAKE_BUILD_TYPE'"
+    ci_info "environment option: \$CI_CMAKE_BUILD_FLAGS: '$CI_CMAKE_BUILD_FLAGS'"
+    ci_info "environment option: \$CI_CMAKE_TOOLCHAIN_FILE: '$CI_CMAKE_TOOLCHAIN_FILE'"
+    ci_info "environment option: \$CI_CMAKE_VARS: '$CI_CMAKE_VARS'"
+    ci_info "environment option: \$CI_CTEST: '$CI_CTEST'"
+    ci_info "environment option: \$CI_CTEST_FLAGS: '$CI_CTEST_FLAGS'"
+    ci_info "environment option: \$CI_CC: '$CI_CC'"
+    ci_info "environment option: \$CI_CC_FLAGS: '$CI_CC_FLAGS'"
+    ci_info "environment option: \$CI_AR: '$CI_AR'"
+    ci_info "environment option: \$CI_RANLIB: '$CI_RANLIB'"
+    ci_info "environment option: \$CI_SANITIZERS: '$CI_SANITIZERS'"
+    ci_info "environment option: \$CI_NO_TEST: '$CI_NO_TEST'"
+    ci_info "environment option: \$CI_NO_INSTALL: '$CI_NO_INSTALL'"
+    ci_info "environment option: \$CI_NO_CLEAN: '$CI_NO_CLEAN'"
+    ci_info "executable: \$CI_CMAKE: $(command -V "$CI_CMAKE")"
+    ci_info "executable: \$CI_CTEST: $(command -V "$CI_CTEST")"
+    [[ $CI_CC ]] &&
+        ci_info "executable: \$CI_CC: $(command -V "$CI_CC")"
+    [[ $CI_AR ]] &&
+        ci_info "executable: \$CI_AR: $(command -V "$CI_AR")"
+    [[ $CI_RANLIB ]] &&
+        ci_info "executable: \$CI_RANLIB: $(command -V "$CI_RANLIB")"
+    ci_info "## END OF CONFIGURATION ##"
+}
+
+function ci_cleanup_old_build {
+    if [[ -e $CI_BUILD_DIR || -e $CI_INSTALL_DIR ]]
+    then
+        ci_info "## START OF PRE-BUILD CLEANUP ##"
+        ci_spawn rm -fr "$CI_BUILD_DIR"
+        ci_spawn rm -fr "$CI_INSTALL_DIR"
+        ci_info "## END OF PRE-BUILD CLEANUP ##"
+    fi
+}
+
+function ci_build {
+    ci_info "## START OF BUILD ##"
+    ci_spawn "$(command -v "$CI_CMAKE")" --version
+    ci_spawn "$(command -v "$CI_CTEST")" --version
+    [[ $CI_CMAKE_GENERATOR == *"Ninja"* ]] &&
+        ci_spawn "$(command -v ninja)" --version
+    # Initialize ALL_CC_FLAGS as a string.
+    local ALL_CC_FLAGS="$CI_CC_FLAGS"
+    [[ $CI_SANITIZERS ]] &&
+        ALL_CC_FLAGS="-fsanitize=$CI_SANITIZERS $ALL_CC_FLAGS"
+    # Initialize ALL_CMAKE_VARS, ALL_CMAKE_BUILD_FLAGS and ALL_CTEST_FLAGS as arrays.
+    local ALL_CMAKE_VARS=()
+    [[ $CI_CMAKE_TOOLCHAIN_FILE ]] &&
+        ALL_CMAKE_VARS+=(-DCMAKE_TOOLCHAIN_FILE="$CI_CMAKE_TOOLCHAIN_FILE")
+    [[ $CI_CC ]] &&
+        ALL_CMAKE_VARS+=(-DCMAKE_C_COMPILER="$CI_CC")
+    [[ $ALL_CC_FLAGS ]] &&
+        ALL_CMAKE_VARS+=(-DCMAKE_C_FLAGS="$ALL_CC_FLAGS")
+    [[ $CI_AR ]] && {
+        # Use the full path of CI_AR to work around a CMake error.
+        ALL_CMAKE_VARS+=(-DCMAKE_AR="$(command -v "$CI_AR")")
+    }
+    [[ $CI_RANLIB ]] && {
+        # Use the full path of CI_RANLIB to work around a CMake error.
+        ALL_CMAKE_VARS+=(-DCMAKE_RANLIB="$(command -v "$CI_RANLIB")")
+    }
+    ALL_CMAKE_VARS+=(-DCMAKE_BUILD_TYPE="$CI_CMAKE_BUILD_TYPE")
+    ALL_CMAKE_VARS+=(-DCMAKE_VERBOSE_MAKEFILE=ON)
+    ALL_CMAKE_VARS+=($CI_CMAKE_VARS)
+    local ALL_CMAKE_BUILD_FLAGS=($CI_CMAKE_BUILD_FLAGS)
+    local ALL_CTEST_FLAGS=($CI_CTEST_FLAGS)
+    # Export the CMake environment variables.
+    [[ $CI_CMAKE_GENERATOR ]] &&
+        ci_spawn export CMAKE_GENERATOR="$CI_CMAKE_GENERATOR"
+    [[ $CI_CMAKE_GENERATOR_PLATFORM ]] &&
+        ci_spawn export CMAKE_GENERATOR_PLATFORM="$CI_CMAKE_GENERATOR_PLATFORM"
+    # Build!
+    # Use $CI_BUILD_TO_SRC_RELDIR and $CI_BUILD_TO_INSTALL_RELDIR
+    # instead of $CI_SRC_DIR and $CI_INSTALL_DIR from this point onwards.
+    ci_spawn mkdir -p "$CI_BUILD_DIR"
+    ci_spawn cd "$CI_BUILD_DIR"
+    [[ $CI_BUILD_TO_SRC_RELDIR -ef $CI_SRC_DIR ]] ||
+        ci_err_internal "bad or missing \$CI_BUILD_TO_SRC_RELDIR"
+    ci_spawn mkdir -p "$CI_INSTALL_DIR"
+    [[ $CI_BUILD_TO_INSTALL_RELDIR -ef $CI_INSTALL_DIR ]] ||
+        ci_err_internal "bad or missing \$CI_BUILD_TO_INSTALL_RELDIR"
+    # Spawn "cmake ...".
+    ci_spawn "$CI_CMAKE" -DCMAKE_INSTALL_PREFIX="$CI_BUILD_TO_INSTALL_RELDIR" \
+                         "${ALL_CMAKE_VARS[@]}" \
+                         "$CI_BUILD_TO_SRC_RELDIR"
+    # Spawn "cmake --build ...".
+    ci_spawn "$CI_CMAKE" --build . \
+                         --config "$CI_CMAKE_BUILD_TYPE" \
+                         "${ALL_CMAKE_BUILD_FLAGS[@]}"
+    ci_expr $((CI_NO_TEST)) || {
+        # Spawn "ctest" if testing is not disabled.
+        ci_spawn "$CI_CTEST" --build-config "$CI_CMAKE_BUILD_TYPE" \
+                             "${ALL_CTEST_FLAGS[@]}"
+    }
+    ci_expr $((CI_NO_INSTALL)) || {
+        # Spawn "cmake --build ... --target install" if installation is not disabled.
+        ci_spawn "$CI_CMAKE" --build . \
+                             --config "$CI_CMAKE_BUILD_TYPE" \
+                             --target install \
+                             "${ALL_CMAKE_BUILD_FLAGS[@]}"
+    }
+    ci_expr $((CI_NO_CLEAN)) || {
+        # Spawn "make --build ... --target clean" if cleaning is not disabled.
+        ci_spawn "$CI_CMAKE" --build . \
+                             --config "$CI_CMAKE_BUILD_TYPE" \
+                             --target clean \
+                             "${ALL_CMAKE_BUILD_FLAGS[@]}"
+    }
+    ci_info "## END OF BUILD ##"
+}
+
+function usage {
+    echo "usage: $CI_SCRIPT_NAME"
+    exit 0
+}
+
+function main {
+    local opt
+    while getopts ":" opt
+    do
+        # This ain't a while-loop. It only pretends to be.
+        [[ $1 == -[?h]* || $1 == --help ]] && usage
+        ci_err "unknown option: '$1'"
+    done
+    shift $((OPTIND - 1))
+    ci_init_build
+    ci_trace_build
+    [[ $# -eq 0 ]] || {
+        ci_info "note: this program accepts environment options only"
+        ci_err "unexpected argument: '$1'"
+    }
+    ci_cleanup_old_build
+    ci_build
+}
+
+main "$@"

ci/ci_verify_configure.sh

@@ -0,0 +1,148 @@
+#!/usr/bin/env bash
+set -e
+
+# Copyright (c) 2019-2024 Cosmin Truta.
+#
+# Use, modification and distribution are subject to the MIT License.
+# Please see the accompanying file LICENSE_MIT.txt
+#
+# SPDX-License-Identifier: MIT
+
+# shellcheck source="ci/lib/ci.lib.sh"
+source "$(dirname "$0")/lib/ci.lib.sh"
+cd "$CI_TOPLEVEL_DIR"
+
+CI_SRC_DIR="$CI_TOPLEVEL_DIR"
+CI_OUT_DIR="$CI_TOPLEVEL_DIR/out"
+CI_BUILD_DIR="$CI_OUT_DIR/ci_verify_configure.$CI_TARGET_SYSTEM.$CI_TARGET_ARCH.build"
+CI_INSTALL_DIR="$CI_OUT_DIR/ci_verify_configure.$CI_TARGET_SYSTEM.$CI_TARGET_ARCH.install"
+
+function ci_init_build {
+    # Ensure that the mandatory variables are initialized.
+    CI_MAKE="${CI_MAKE:-make}"
+    [[ "$CI_TARGET_SYSTEM.$CI_TARGET_ARCH" != "$CI_BUILD_SYSTEM.$CI_BUILD_ARCH" ]] || {
+        # For native builds, set CI_CC to "cc" by default if the cc command is available.
+        # The configure script defaults CC to "gcc", which is not always a good idea.
+        [[ -x $(command -v cc) ]] && CI_CC="${CI_CC:-cc}"
+    }
+    # Ensure that the CI_ variables that cannot be customized reliably are not initialized.
+    [[ ! $CI_CONFIGURE_VARS ]] ||
+        ci_err "unsupported: \$CI_CONFIGURE_VARS='$CI_CONFIGURE_VARS'"
+    [[ ! $CI_MAKE_VARS ]] ||
+        ci_err "unsupported: \$CI_MAKE_VARS='$CI_MAKE_VARS'"
+}
+
+function ci_trace_build {
+    ci_info "## START OF CONFIGURATION ##"
+    ci_info "build arch: $CI_BUILD_ARCH"
+    ci_info "build system: $CI_BUILD_SYSTEM"
+    [[ "$CI_TARGET_SYSTEM.$CI_TARGET_ARCH" != "$CI_BUILD_SYSTEM.$CI_BUILD_ARCH" ]] && {
+        ci_info "target arch: $CI_TARGET_ARCH"
+        ci_info "target system: $CI_TARGET_SYSTEM"
+    }
+    ci_info "source directory: $CI_SRC_DIR"
+    ci_info "build directory: $CI_BUILD_DIR"
+    ci_info "install directory: $CI_INSTALL_DIR"
+    ci_info "environment option: \$CI_CONFIGURE_FLAGS: '$CI_CONFIGURE_FLAGS'"
+    ci_info "environment option: \$CI_MAKE: '$CI_MAKE'"
+    ci_info "environment option: \$CI_MAKE_FLAGS: '$CI_MAKE_FLAGS'"
+    ci_info "environment option: \$CI_CC: '$CI_CC'"
+    ci_info "environment option: \$CI_CC_FLAGS: '$CI_CC_FLAGS'"
+    ci_info "environment option: \$CI_CPP: '$CI_CPP'"
+    ci_info "environment option: \$CI_CPP_FLAGS: '$CI_CPP_FLAGS'"
+    ci_info "environment option: \$CI_AR: '$CI_AR'"
+    ci_info "environment option: \$CI_RANLIB: '$CI_RANLIB'"
+    ci_info "environment option: \$CI_LD: '$CI_LD'"
+    ci_info "environment option: \$CI_LD_FLAGS: '$CI_LD_FLAGS'"
+    ci_info "environment option: \$CI_SANITIZERS: '$CI_SANITIZERS'"
+    ci_info "environment option: \$CI_NO_TEST: '$CI_NO_TEST'"
+    ci_info "environment option: \$CI_NO_INSTALL: '$CI_NO_INSTALL'"
+    ci_info "environment option: \$CI_NO_CLEAN: '$CI_NO_CLEAN'"
+    ci_info "executable: \$CI_MAKE: $(command -V "$CI_MAKE")"
+    [[ $CI_CC ]] &&
+        ci_info "executable: \$CI_CC: $(command -V "$CI_CC")"
+    [[ $CI_CPP ]] &&
+        ci_info "executable: \$CI_CPP: $(command -V "$CI_CPP")"
+    [[ $CI_AR ]] &&
+        ci_info "executable: \$CI_AR: $(command -V "$CI_AR")"
+    [[ $CI_RANLIB ]] &&
+        ci_info "executable: \$CI_RANLIB: $(command -V "$CI_RANLIB")"
+    [[ $CI_LD ]] &&
+        ci_info "executable: \$CI_LD: $(command -V "$CI_LD")"
+    ci_info "## END OF CONFIGURATION ##"
+}
+
+function ci_cleanup_old_build {
+    if [[ -e $CI_BUILD_DIR || -e $CI_INSTALL_DIR ]]
+    then
+        ci_info "## START OF PRE-BUILD CLEANUP ##"
+        ci_spawn rm -fr "$CI_BUILD_DIR"
+        ci_spawn rm -fr "$CI_INSTALL_DIR"
+        ci_info "## END OF PRE-BUILD CLEANUP ##"
+    fi
+}
+
+function ci_build {
+    ci_info "## START OF BUILD ##"
+    # Export the configure build environment.
+    [[ $CI_CC ]] && ci_spawn export CC="$CI_CC"
+    [[ $CI_CC_FLAGS ]] && ci_spawn export CFLAGS="$CI_CC_FLAGS"
+    [[ $CI_CPP ]] && ci_spawn export CPP="$CI_CPP"
+    [[ $CI_CPP_FLAGS ]] && ci_spawn export CPPFLAGS="$CI_CPP_FLAGS"
+    [[ $CI_AR ]] && ci_spawn export AR="$CI_AR"
+    [[ $CI_RANLIB ]] && ci_spawn export RANLIB="$CI_RANLIB"
+    [[ $CI_LD ]] && ci_spawn export LD="$CI_LD"
+    [[ $CI_LD_FLAGS ]] && ci_spawn export LDFLAGS="$CI_LD_FLAGS"
+    [[ $CI_SANITIZERS ]] && {
+        ci_spawn export CFLAGS="-fsanitize=$CI_SANITIZERS ${CFLAGS:-"-O2"}"
+        ci_spawn export LDFLAGS="-fsanitize=$CI_SANITIZERS $LDFLAGS"
+    }
+    # Build!
+    ci_spawn mkdir -p "$CI_BUILD_DIR"
+    ci_spawn cd "$CI_BUILD_DIR"
+    # Spawn "configure".
+    ci_spawn "$CI_SRC_DIR/configure" --prefix="$CI_INSTALL_DIR" $CI_CONFIGURE_FLAGS
+    # Spawn "make".
+    ci_spawn "$CI_MAKE" $CI_MAKE_FLAGS
+    ci_expr $((CI_NO_TEST)) || {
+        # Spawn "make test" if testing is not disabled.
+        ci_spawn "$CI_MAKE" $CI_MAKE_FLAGS test
+    }
+    ci_expr $((CI_NO_INSTALL)) || {
+        # Spawn "make install" if installation is not disabled.
+        ci_spawn "$CI_MAKE" $CI_MAKE_FLAGS install
+    }
+    ci_expr $((CI_NO_CLEAN)) || {
+        # Spawn "make clean" and "make distclean" if cleaning is not disabled.
+        ci_spawn "$CI_MAKE" $CI_MAKE_FLAGS clean
+        ci_spawn "$CI_MAKE" $CI_MAKE_FLAGS distclean
+    }
+    ci_info "## END OF BUILD ##"
+}
+
+function usage {
+    echo "usage: $CI_SCRIPT_NAME"
+    exit 0
+}
+
+function main {
+    local opt
+    while getopts ":" opt
+    do
+        # This ain't a while-loop. It only pretends to be.
+        [[ $1 == -[?h]* || $1 == --help ]] && usage
+        ci_err "unknown option: '$1'"
+    done
+    shift $((OPTIND - 1))
+    # And... go!
+    ci_init_build
+    ci_trace_build
+    [[ $# -eq 0 ]] || {
+        ci_info "note: this program accepts environment options only"
+        ci_err "unexpected argument: '$1'"
+    }
+    ci_cleanup_old_build
+    ci_build
+}
+
+main "$@"

ci/ci_verify_makefiles.sh

@@ -0,0 +1,163 @@
+#!/usr/bin/env bash
+set -e
+
+# Copyright (c) 2019-2024 Cosmin Truta.
+#
+# Use, modification and distribution are subject to the MIT License.
+# Please see the accompanying file LICENSE_MIT.txt
+#
+# SPDX-License-Identifier: MIT
+
+# shellcheck source="ci/lib/ci.lib.sh"
+source "$(dirname "$0")/lib/ci.lib.sh"
+cd "$CI_TOPLEVEL_DIR"
+
+CI_SRC_DIR="$CI_TOPLEVEL_DIR"
+
+function ci_init_build {
+    # Ensure that the mandatory variables are initialized.
+    CI_MAKE="${CI_MAKE:-make}"
+    case "$CI_CC" in
+    ( *clang* )
+        CI_MAKEFILES="${CI_MAKEFILES:-"scripts/makefile.clang"}" ;;
+    ( *gcc* )
+        CI_MAKEFILES="${CI_MAKEFILES:-"scripts/makefile.gcc"}" ;;
+    ( * )
+        CI_MAKEFILES="${CI_MAKEFILES:-"scripts/makefile.std"}" ;;
+    esac
+}
+
+function ci_trace_build {
+    ci_info "## START OF CONFIGURATION ##"
+    ci_info "build arch: $CI_BUILD_ARCH"
+    ci_info "build system: $CI_BUILD_SYSTEM"
+    [[ "$CI_TARGET_SYSTEM.$CI_TARGET_ARCH" != "$CI_BUILD_SYSTEM.$CI_BUILD_ARCH" ]] && {
+        ci_info "target arch: $CI_TARGET_ARCH"
+        ci_info "target system: $CI_TARGET_SYSTEM"
+    }
+    ci_info "source directory: $CI_SRC_DIR"
+    ci_info "environment option: \$CI_MAKEFILES: '$CI_MAKEFILES'"
+    ci_info "environment option: \$CI_MAKE: '$CI_MAKE'"
+    ci_info "environment option: \$CI_MAKE_FLAGS: '$CI_MAKE_FLAGS'"
+    ci_info "environment option: \$CI_MAKE_VARS: '$CI_MAKE_VARS'"
+    ci_info "environment option: \$CI_CC: '$CI_CC'"
+    ci_info "environment option: \$CI_CC_FLAGS: '$CI_CC_FLAGS'"
+    ci_info "environment option: \$CI_CPP: '$CI_CPP'"
+    ci_info "environment option: \$CI_CPP_FLAGS: '$CI_CPP_FLAGS'"
+    ci_info "environment option: \$CI_AR: '$CI_AR'"
+    ci_info "environment option: \$CI_RANLIB: '$CI_RANLIB'"
+    ci_info "environment option: \$CI_LD: '$CI_LD'"
+    ci_info "environment option: \$CI_LD_FLAGS: '$CI_LD_FLAGS'"
+    ci_info "environment option: \$CI_LIBS: '$CI_LIBS'"
+    ci_info "environment option: \$CI_SANITIZERS: '$CI_SANITIZERS'"
+    ci_info "environment option: \$CI_NO_TEST: '$CI_NO_TEST'"
+    ci_info "environment option: \$CI_NO_CLEAN: '$CI_NO_CLEAN'"
+    ci_info "executable: \$CI_MAKE: $(command -V "$CI_MAKE")"
+    [[ $CI_CC ]] &&
+        ci_info "executable: \$CI_CC: $(command -V "$CI_CC")"
+    [[ $CI_CPP ]] &&
+        ci_info "executable: \$CI_CPP: $(command -V "$CI_CPP")"
+    [[ $CI_AR ]] &&
+        ci_info "executable: \$CI_AR: $(command -V "$CI_AR")"
+    [[ $CI_RANLIB ]] &&
+        ci_info "executable: \$CI_RANLIB: $(command -V "$CI_RANLIB")"
+    [[ $CI_LD ]] &&
+        ci_info "executable: \$CI_LD: $(command -V "$CI_LD")"
+    ci_info "## END OF CONFIGURATION ##"
+}
+
+function ci_cleanup_old_build {
+    # Any old makefile-based build will most likely leave a mess
+    # of object files behind if interrupted, e.g., via Ctrl+C.
+    # There may be other files behind, depending on what makefile
+    # had been used. We cannot easily enumerate all of those.
+    # Fortunately, for a clean makefiles-based build, it should be
+    # sufficient to remove the old object files only.
+    ci_info "## START OF PRE-BUILD CLEANUP ##"
+    local MY_FILE
+    find "$CI_SRC_DIR" -maxdepth 1 \( -iname "*.o" -o -iname "*.obj" \) |
+        while IFS="" read -r MY_FILE
+        do
+            ci_spawn rm -fr "$MY_FILE"
+        done
+    ci_info "## END OF PRE-BUILD CLEANUP ##"
+}
+
+function ci_build {
+    ci_info "## START OF BUILD ##"
+    # Initialize ALL_CC_FLAGS and ALL_LD_FLAGS as strings.
+    local ALL_CC_FLAGS="$CI_CC_FLAGS"
+    local ALL_LD_FLAGS="$CI_LD_FLAGS"
+    [[ $CI_SANITIZERS ]] && {
+        ALL_CC_FLAGS="-fsanitize=$CI_SANITIZERS ${ALL_CC_FLAGS:-"-O2"}"
+        ALL_LD_FLAGS="-fsanitize=$CI_SANITIZERS $ALL_LD_FLAGS"
+    }
+    # Initialize ALL_MAKE_FLAGS and ALL_MAKE_VARS as arrays.
+    local ALL_MAKE_FLAGS=($CI_MAKE_FLAGS)
+    local ALL_MAKE_VARS=()
+    [[ $CI_CC ]] && ALL_MAKE_VARS+=(CC="$CI_CC")
+    [[ $ALL_CC_FLAGS ]] && ALL_MAKE_VARS+=(CFLAGS="$ALL_CC_FLAGS")
+    [[ $CI_CPP ]] && ALL_MAKE_VARS+=(CPP="$CI_CPP")
+    [[ $CI_CPP_FLAGS ]] && ALL_MAKE_VARS+=(CPPFLAGS="$CI_CPP_FLAGS")
+    [[ $CI_AR ]] && ALL_MAKE_VARS+=(
+        AR="${CI_AR:-ar}"
+        AR_RC="${CI_AR:-ar} rc"
+    )
+    [[ $CI_RANLIB ]] && ALL_MAKE_VARS+=(RANLIB="$CI_RANLIB")
+    [[ $CI_LD ]] && ALL_MAKE_VARS+=(LD="$CI_LD")
+    [[ $ALL_LD_FLAGS ]] && ALL_MAKE_VARS+=(LDFLAGS="$ALL_LD_FLAGS")
+    [[ $CI_LIBS ]] && ALL_MAKE_VARS+=(LIBS="$CI_LIBS")
+    ALL_MAKE_VARS+=($CI_MAKE_VARS)
+    # Build!
+    local MY_MAKEFILE
+    for MY_MAKEFILE in $CI_MAKEFILES
+    do
+        ci_info "using makefile: $MY_MAKEFILE"
+        # Spawn "make".
+        ci_spawn "$CI_MAKE" -f "$MY_MAKEFILE" \
+                            "${ALL_MAKE_FLAGS[@]}" \
+                            "${ALL_MAKE_VARS[@]}"
+        ci_expr $((CI_NO_TEST)) || {
+            # Spawn "make test" if testing is not disabled.
+            ci_spawn "$CI_MAKE" -f "$MY_MAKEFILE" \
+                                "${ALL_MAKE_FLAGS[@]}" \
+                                "${ALL_MAKE_VARS[@]}" \
+                                test
+        }
+        ci_expr $((CI_NO_CLEAN)) || {
+            # Spawn "make clean" if cleaning is not disabled.
+            ci_spawn "$CI_MAKE" -f "$MY_MAKEFILE" \
+                                "${ALL_MAKE_FLAGS[@]}" \
+                                "${ALL_MAKE_VARS[@]}" \
+                                clean
+        }
+    done
+    ci_info "## END OF BUILD ##"
+}
+
+function usage {
+    echo "usage: $CI_SCRIPT_NAME"
+    exit 0
+}
+
+function main {
+    local opt
+    while getopts ":" opt
+    do
+        # This ain't a while-loop. It only pretends to be.
+        [[ $1 == -[?h]* || $1 == --help ]] && usage
+        ci_err "unknown option: '$1'"
+    done
+    shift $((OPTIND - 1))
+    # And... go!
+    ci_init_build
+    ci_trace_build
+    [[ $# -eq 0 ]] || {
+        ci_info "note: this program accepts environment options only"
+        ci_err "unexpected argument: '$1'"
+    }
+    ci_cleanup_old_build
+    ci_build
+}
+
+main "$@"

ci/lib/ci.lib.sh

@@ -0,0 +1,90 @@
+# Copyright (c) 2019-2024 Cosmin Truta.
+#
+# Use, modification and distribution are subject to the MIT License.
+# Please see the accompanying file LICENSE_MIT.txt
+#
+# SPDX-License-Identifier: MIT
+
+test -f "$BASH_SOURCE" ||
+    echo >&2 "warning: this module requires Bash version 3 or newer"
+test "${#BASH_SOURCE[@]}" -gt 1 ||
+    echo >&2 "warning: this module should be sourced from a Bash script"
+
+# Reset the locale to avoid surprises from locale-dependent commands.
+export LC_ALL=C
+export LANG=C
+export LANGUAGE=C
+
+# Reset CDPATH to avoid surprises from the "cd" command.
+export CDPATH=""
+
+# Initialize the global constants CI_SCRIPT_{NAME,DIR} and CI_TOPLEVEL_DIR.
+CI_SCRIPT_NAME="$(basename -- "$0")"
+CI_SCRIPT_DIR="$(cd "$(dirname -- "$0")" && pwd)"
+CI_TOPLEVEL_DIR="$(cd "$(dirname -- "${BASH_SOURCE[0]}")/../.." && pwd)"
+
+# Initialize the global constants CI_BUILD_{...} for the host build platform.
+CI_BUILD_ARCH="${CI_BUILD_ARCH:-"$(uname -m | tr 'A-Z/\.-' 'a-z____')"}"
+CI_BUILD_SYSTEM="${CI_BUILD_SYSTEM:-"$(uname -s | tr 'A-Z/\.-' 'a-z____')"}"
+
+# Initialize the global constants CI_TARGET_{...} for the target platform.
+CI_TARGET_ARCH="${CI_TARGET_ARCH:-"$CI_BUILD_ARCH"}"
+CI_TARGET_SYSTEM="${CI_TARGET_SYSTEM:-"$CI_BUILD_SYSTEM"}"
+
+function ci_info {
+    printf >&2 "%s: %s\\n" "$CI_SCRIPT_NAME" "$*"
+}
+
+function ci_warn {
+    printf >&2 "%s: warning: %s\\n" "$CI_SCRIPT_NAME" "$*"
+}
+
+function ci_err {
+    printf >&2 "%s: error: %s\\n" "$CI_SCRIPT_NAME" "$*"
+    exit 2
+}
+
+function ci_err_internal {
+    printf >&2 "%s: internal error: %s\\n" "$CI_SCRIPT_NAME" "$*"
+    printf >&2 "ABORTED\\n"
+    # Exit with the conventional SIGABRT code.
+    exit 134
+}
+
+function ci_expr {
+    if [[ ${*:-0} == [0-9] ]]
+    then
+        # This is the same as in the else-branch below, albeit much faster
+        # for our intended use cases.
+        return $((!$1))
+    else
+        # The funny-looking compound command "... && return $? || return $?"
+        # allows the execution to continue uninterrupted under "set -e".
+        expr >/dev/null "$@" && return $? || return $?
+    fi
+}
+
+function ci_spawn {
+    printf >&2 "%s: executing:" "$CI_SCRIPT_NAME"
+    printf >&2 " %q" "$@"
+    printf >&2 "\\n"
+    "$@"
+}
+
+# Ensure that the internal initialization is correct.
+[[ $CI_TOPLEVEL_DIR/ci/lib/ci.lib.sh -ef ${BASH_SOURCE[0]} ]] ||
+    ci_err_internal "bad or missing \$CI_TOPLEVEL_DIR"
+[[ $CI_SCRIPT_DIR/$CI_SCRIPT_NAME -ef $0 ]] ||
+    ci_err_internal "bad or missing \$CI_SCRIPT_DIR/\$CI_SCRIPT_NAME"
+[[ $CI_BUILD_ARCH && $CI_BUILD_SYSTEM ]] ||
+    ci_err_internal "missing \$CI_BUILD_ARCH or \$CI_BUILD_SYSTEM"
+[[ $CI_TARGET_ARCH && $CI_TARGET_SYSTEM ]] ||
+    ci_err_internal "missing \$CI_TARGET_ARCH or \$CI_TARGET_SYSTEM"
+
+# Ensure that the user initialization is correct.
+[[ ${CI_NO_TEST:-0} == [01] ]] ||
+    ci_err "bad boolean option: \$CI_NO_TEST: '$CI_NO_TEST'"
+[[ ${CI_NO_INSTALL:-0} == [01] ]] ||
+    ci_err "bad boolean option: \$CI_NO_INSTALL: '$CI_NO_INSTALL'"
+[[ ${CI_NO_CLEAN:-0} == [01] ]] ||
+    ci_err "bad boolean option: \$CI_NO_CLEAN: '$CI_NO_CLEAN'"

compile

@@ -0,0 +1,348 @@
+#! /bin/sh
+# Wrapper for compilers which do not understand '-c -o'.
+
+scriptversion=2018-03-07.03; # UTC
+
+# Copyright (C) 1999-2021 Free Software Foundation, Inc.
+# Written by Tom Tromey <tromey@cygnus.com>.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2, or (at your option)
+# any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+# As a special exception to the GNU General Public License, if you
+# distribute this file as part of a program that contains a
+# configuration script generated by Autoconf, you may include it under
+# the same distribution terms that you use for the rest of that program.
+
+# This file is maintained in Automake, please report
+# bugs to <bug-automake@gnu.org> or send patches to
+# <automake-patches@gnu.org>.
+
+nl='
+'
+
+# We need space, tab and new line, in precisely that order.  Quoting is
+# there to prevent tools from complaining about whitespace usage.
+IFS=" ""	$nl"
+
+file_conv=
+
+# func_file_conv build_file lazy
+# Convert a $build file to $host form and store it in $file
+# Currently only supports Windows hosts. If the determined conversion
+# type is listed in (the comma separated) LAZY, no conversion will
+# take place.
+func_file_conv ()
+{
+  file=$1
+  case $file in
+    / | /[!/]*) # absolute file, and not a UNC file
+      if test -z "$file_conv"; then
+	# lazily determine how to convert abs files
+	case `uname -s` in
+	  MINGW*)
+	    file_conv=mingw
+	    ;;
+	  CYGWIN* | MSYS*)
+	    file_conv=cygwin
+	    ;;
+	  *)
+	    file_conv=wine
+	    ;;
+	esac
+      fi
+      case $file_conv/,$2, in
+	*,$file_conv,*)
+	  ;;
+	mingw/*)
+	  file=`cmd //C echo "$file " | sed -e 's/"\(.*\) " *$/\1/'`
+	  ;;
+	cygwin/* | msys/*)
+	  file=`cygpath -m "$file" || echo "$file"`
+	  ;;
+	wine/*)
+	  file=`winepath -w "$file" || echo "$file"`
+	  ;;
+      esac
+      ;;
+  esac
+}
+
+# func_cl_dashL linkdir
+# Make cl look for libraries in LINKDIR
+func_cl_dashL ()
+{
+  func_file_conv "$1"
+  if test -z "$lib_path"; then
+    lib_path=$file
+  else
+    lib_path="$lib_path;$file"
+  fi
+  linker_opts="$linker_opts -LIBPATH:$file"
+}
+
+# func_cl_dashl library
+# Do a library search-path lookup for cl
+func_cl_dashl ()
+{
+  lib=$1
+  found=no
+  save_IFS=$IFS
+  IFS=';'
+  for dir in $lib_path $LIB
+  do
+    IFS=$save_IFS
+    if $shared && test -f "$dir/$lib.dll.lib"; then
+      found=yes
+      lib=$dir/$lib.dll.lib
+      break
+    fi
+    if test -f "$dir/$lib.lib"; then
+      found=yes
+      lib=$dir/$lib.lib
+      break
+    fi
+    if test -f "$dir/lib$lib.a"; then
+      found=yes
+      lib=$dir/lib$lib.a
+      break
+    fi
+  done
+  IFS=$save_IFS
+
+  if test "$found" != yes; then
+    lib=$lib.lib
+  fi
+}
+
+# func_cl_wrapper cl arg...
+# Adjust compile command to suit cl
+func_cl_wrapper ()
+{
+  # Assume a capable shell
+  lib_path=
+  shared=:
+  linker_opts=
+  for arg
+  do
+    if test -n "$eat"; then
+      eat=
+    else
+      case $1 in
+	-o)
+	  # configure might choose to run compile as 'compile cc -o foo foo.c'.
+	  eat=1
+	  case $2 in
+	    *.o | *.[oO][bB][jJ])
+	      func_file_conv "$2"
+	      set x "$@" -Fo"$file"
+	      shift
+	      ;;
+	    *)
+	      func_file_conv "$2"
+	      set x "$@" -Fe"$file"
+	      shift
+	      ;;
+	  esac
+	  ;;
+	-I)
+	  eat=1
+	  func_file_conv "$2" mingw
+	  set x "$@" -I"$file"
+	  shift
+	  ;;
+	-I*)
+	  func_file_conv "${1#-I}" mingw
+	  set x "$@" -I"$file"
+	  shift
+	  ;;
+	-l)
+	  eat=1
+	  func_cl_dashl "$2"
+	  set x "$@" "$lib"
+	  shift
+	  ;;
+	-l*)
+	  func_cl_dashl "${1#-l}"
+	  set x "$@" "$lib"
+	  shift
+	  ;;
+	-L)
+	  eat=1
+	  func_cl_dashL "$2"
+	  ;;
+	-L*)
+	  func_cl_dashL "${1#-L}"
+	  ;;
+	-static)
+	  shared=false
+	  ;;
+	-Wl,*)
+	  arg=${1#-Wl,}
+	  save_ifs="$IFS"; IFS=','
+	  for flag in $arg; do
+	    IFS="$save_ifs"
+	    linker_opts="$linker_opts $flag"
+	  done
+	  IFS="$save_ifs"
+	  ;;
+	-Xlinker)
+	  eat=1
+	  linker_opts="$linker_opts $2"
+	  ;;
+	-*)
+	  set x "$@" "$1"
+	  shift
+	  ;;
+	*.cc | *.CC | *.cxx | *.CXX | *.[cC]++)
+	  func_file_conv "$1"
+	  set x "$@" -Tp"$file"
+	  shift
+	  ;;
+	*.c | *.cpp | *.CPP | *.lib | *.LIB | *.Lib | *.OBJ | *.obj | *.[oO])
+	  func_file_conv "$1" mingw
+	  set x "$@" "$file"
+	  shift
+	  ;;
+	*)
+	  set x "$@" "$1"
+	  shift
+	  ;;
+      esac
+    fi
+    shift
+  done
+  if test -n "$linker_opts"; then
+    linker_opts="-link$linker_opts"
+  fi
+  exec "$@" $linker_opts
+  exit 1
+}
+
+eat=
+
+case $1 in
+  '')
+     echo "$0: No command.  Try '$0 --help' for more information." 1>&2
+     exit 1;
+     ;;
+  -h | --h*)
+    cat <<\EOF
+Usage: compile [--help] [--version] PROGRAM [ARGS]
+
+Wrapper for compilers which do not understand '-c -o'.
+Remove '-o dest.o' from ARGS, run PROGRAM with the remaining
+arguments, and rename the output as expected.
+
+If you are trying to build a whole package this is not the
+right script to run: please start by reading the file 'INSTALL'.
+
+Report bugs to <bug-automake@gnu.org>.
+EOF
+    exit $?
+    ;;
+  -v | --v*)
+    echo "compile $scriptversion"
+    exit $?
+    ;;
+  cl | *[/\\]cl | cl.exe | *[/\\]cl.exe | \
+  icl | *[/\\]icl | icl.exe | *[/\\]icl.exe )
+    func_cl_wrapper "$@"      # Doesn't return...
+    ;;
+esac
+
+ofile=
+cfile=
+
+for arg
+do
+  if test -n "$eat"; then
+    eat=
+  else
+    case $1 in
+      -o)
+	# configure might choose to run compile as 'compile cc -o foo foo.c'.
+	# So we strip '-o arg' only if arg is an object.
+	eat=1
+	case $2 in
+	  *.o | *.obj)
+	    ofile=$2
+	    ;;
+	  *)
+	    set x "$@" -o "$2"
+	    shift
+	    ;;
+	esac
+	;;
+      *.c)
+	cfile=$1
+	set x "$@" "$1"
+	shift
+	;;
+      *)
+	set x "$@" "$1"
+	shift
+	;;
+    esac
+  fi
+  shift
+done
+
+if test -z "$ofile" || test -z "$cfile"; then
+  # If no '-o' option was seen then we might have been invoked from a
+  # pattern rule where we don't need one.  That is ok -- this is a
+  # normal compilation that the losing compiler can handle.  If no
+  # '.c' file was seen then we are probably linking.  That is also
+  # ok.
+  exec "$@"
+fi
+
+# Name of file we expect compiler to create.
+cofile=`echo "$cfile" | sed 's|^.*[\\/]||; s|^[a-zA-Z]:||; s/\.c$/.o/'`
+
+# Create the lock directory.
+# Note: use '[/\\:.-]' here to ensure that we don't use the same name
+# that we are using for the .o file.  Also, base the name on the expected
+# object file name, since that is what matters with a parallel build.
+lockdir=`echo "$cofile" | sed -e 's|[/\\:.-]|_|g'`.d
+while true; do
+  if mkdir "$lockdir" >/dev/null 2>&1; then
+    break
+  fi
+  sleep 1
+done
+# FIXME: race condition here if user kills between mkdir and trap.
+trap "rmdir '$lockdir'; exit 1" 1 2 15
+
+# Run the compile.
+"$@"
+ret=$?
+
+if test -f "$cofile"; then
+  test "$cofile" = "$ofile" || mv "$cofile" "$ofile"
+elif test -f "${cofile}bj"; then
+  test "${cofile}bj" = "$ofile" || mv "${cofile}bj" "$ofile"
+fi
+
+rmdir "$lockdir"
+exit $ret
+
+# Local Variables:
+# mode: shell-script
+# sh-indentation: 2
+# eval: (add-hook 'before-save-hook 'time-stamp)
+# time-stamp-start: "scriptversion="
+# time-stamp-format: "%:y-%02m-%02d.%02H"
+# time-stamp-time-zone: "UTC0"
+# time-stamp-end: "; # UTC"
+# End:

config.h.in

@@ -0,0 +1,135 @@
+/* config.h.in.  Generated from configure.ac by autoheader.  */
+
+/* Define to 1 if you have the <dlfcn.h> header file. */
+#undef HAVE_DLFCN_H
+
+/* Define to 1 if you have the 'feenableexcept' function. */
+#undef HAVE_FEENABLEEXCEPT
+
+/* Define to 1 if you have the <inttypes.h> header file. */
+#undef HAVE_INTTYPES_H
+
+/* Define to 1 if you have the 'm' library (-lm). */
+#undef HAVE_LIBM
+
+/* Define to 1 if you have the 'z' library (-lz). */
+#undef HAVE_LIBZ
+
+/* Define to 1 if you have the 'pow' function. */
+#undef HAVE_POW
+
+/* Define to 1 if you have the <stdint.h> header file. */
+#undef HAVE_STDINT_H
+
+/* Define to 1 if you have the <stdio.h> header file. */
+#undef HAVE_STDIO_H
+
+/* Define to 1 if you have the <stdlib.h> header file. */
+#undef HAVE_STDLIB_H
+
+/* Define to 1 if you have the <strings.h> header file. */
+#undef HAVE_STRINGS_H
+
+/* Define to 1 if you have the <string.h> header file. */
+#undef HAVE_STRING_H
+
+/* Define to 1 if you have the <sys/stat.h> header file. */
+#undef HAVE_SYS_STAT_H
+
+/* Define to 1 if you have the <sys/types.h> header file. */
+#undef HAVE_SYS_TYPES_H
+
+/* Define to 1 if you have the <unistd.h> header file. */
+#undef HAVE_UNISTD_H
+
+/* Define to the sub-directory where libtool stores uninstalled libraries. */
+#undef LT_OBJDIR
+
+/* Name of package */
+#undef PACKAGE
+
+/* Define to the address where bug reports for this package should be sent. */
+#undef PACKAGE_BUGREPORT
+
+/* Define to the full name of this package. */
+#undef PACKAGE_NAME
+
+/* Define to the full name and version of this package. */
+#undef PACKAGE_STRING
+
+/* Define to the one symbol short name of this package. */
+#undef PACKAGE_TARNAME
+
+/* Define to the home page for this package. */
+#undef PACKAGE_URL
+
+/* Define to the version of this package. */
+#undef PACKAGE_VERSION
+
+/* Turn on ARM Neon optimizations at run-time */
+#undef PNG_ARM_NEON_API_SUPPORTED
+
+/* Check for ARM Neon support at run-time */
+#undef PNG_ARM_NEON_CHECK_SUPPORTED
+
+/* Enable ARM Neon optimizations */
+#undef PNG_ARM_NEON_OPT
+
+/* Enable Intel SSE optimizations */
+#undef PNG_INTEL_SSE_OPT
+
+/* Enable LOONGARCH LSX optimizations */
+#undef PNG_LOONGARCH_LSX_OPT
+
+/* Turn on MIPS MMI optimizations at run-time */
+#undef PNG_MIPS_MMI_API_SUPPORTED
+
+/* Check for MIPS MMI support at run-time */
+#undef PNG_MIPS_MMI_CHECK_SUPPORTED
+
+/* Enable MIPS MMI optimizations */
+#undef PNG_MIPS_MMI_OPT
+
+/* Turn on MIPS MSA optimizations at run-time */
+#undef PNG_MIPS_MSA_API_SUPPORTED
+
+/* Check for MIPS MSA support at run-time */
+#undef PNG_MIPS_MSA_CHECK_SUPPORTED
+
+/* Enable MIPS MSA optimizations */
+#undef PNG_MIPS_MSA_OPT
+
+/* Turn on POWERPC VSX optimizations at run-time */
+#undef PNG_POWERPC_VSX_API_SUPPORTED
+
+/* Check for POWERPC VSX support at run-time */
+#undef PNG_POWERPC_VSX_CHECK_SUPPORTED
+
+/* Enable POWERPC VSX optimizations */
+#undef PNG_POWERPC_VSX_OPT
+
+/* Define to 1 if all of the C89 standard headers exist (not just the ones
+   required in a freestanding environment). This macro is provided for
+   backward compatibility; new code need not use it. */
+#undef STDC_HEADERS
+
+/* Define to 1 if your <sys/time.h> declares 'struct tm'. */
+#undef TM_IN_SYS_TIME
+
+/* Version number of package */
+#undef VERSION
+
+/* Define to the equivalent of the C99 'restrict' keyword, or to
+   nothing if this is not supported.  Do not define if restrict is
+   supported only directly.  */
+#undef restrict
+/* Work around a bug in older versions of Sun C++, which did not
+   #define __restrict__ or support _Restrict or __restrict__
+   even though the corresponding Sun C compiler ended up with
+   "#define restrict _Restrict" or "#define restrict __restrict__"
+   in the previous line.  This workaround can be removed once
+   we assume Oracle Developer Studio 12.5 (2016) or later.  */
+#if defined __SUNPRO_CC && !defined __RESTRICT && !defined __restrict__
+# define _Restrict
+# define __restrict__
+#endif

configure.ac

@@ -1,7 +1,7 @@
 # configure.ac
 
+# Copyright (c) 2018-2024 Cosmin Truta
 # Copyright (c) 2004-2016 Glenn Randers-Pehrson
-# Last changed in libpng 1.6.25 [October 20, 2016]
 
 # This code is released under the libpng license.
 # For conditions of distribution and use, see the disclaimer
@@ -25,8 +25,8 @@ AC_PREREQ([2.68])
 
 dnl Version number stuff here:
 
-AC_INIT([libpng],[1.6.26],[png-mng-implement@lists.sourceforge.net])
+AC_INIT([libpng],[1.6.41],[png-mng-implement@lists.sourceforge.net])
-AC_CONFIG_MACRO_DIR([scripts])
+AC_CONFIG_MACRO_DIR([scripts/autoconf])
 
 # libpng does not follow GNU file name conventions (hence 'foreign')
 # color-tests requires automake 1.11 or later
@@ -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=1.6.26
+PNGLIB_VERSION=1.6.41
 PNGLIB_MAJOR=1
 PNGLIB_MINOR=6
-PNGLIB_RELEASE=26
+PNGLIB_RELEASE=41
 
 dnl End of version number stuff
 
@@ -89,9 +89,27 @@ fi
 DFNCPP="$CPP"
 AC_SUBST(DFNCPP)
 
-# -Werror cannot be passed to GCC in CFLAGS because configure will fail (it
+AC_ARG_ENABLE([tests],
-# checks the compiler with a program that generates a warning), add the
+   AS_HELP_STRING([--disable-tests],
-# following option to deal with this
+      [do not build the test programs (default is to build)]),
+      [enable_tests="$enableval"],
+      [enable_tests=yes])
+
+AM_CONDITIONAL([ENABLE_TESTS],
+   [test "$enable_tests" != "no"])
+
+AC_ARG_ENABLE([tools],
+   AS_HELP_STRING([--disable-tools],
+      [do not build the auxiliary tools (default is to build)]),
+      [enable_tools="$enableval"],
+      [enable_tools=yes])
+
+AM_CONDITIONAL([ENABLE_TOOLS],
+   [test "$enable_tools" != "no"])
+
+# -Werror cannot be passed to GCC in CFLAGS because configure will fail
+# (it checks the compiler with a program that generates a warning).
+# Add the following option to deal with this:
 AC_ARG_VAR(PNG_COPTS,
    [additional flags for the C compiler, use this for options that would]
    [cause configure itself to fail])
@@ -114,10 +132,10 @@ AC_ARG_ENABLE(werror,
       CFLAGS="$sav_CFLAGS"
     fi],)
 
-# For GCC 5 the default mode for C is -std=gnu11 instead of -std=gnu89
+# For GCC 5 the default mode for C is -std=gnu11 instead of -std=gnu89.
-# In pngpriv.h we request just the POSIX 1003.1 and C89 APIs by defining _POSIX_SOURCE to 1
+# In pngpriv.h we request just the POSIX 1003.1 and C89 APIs by defining
-# This is incompatible with the new default mode, so we test for that and force the 
+# _POSIX_SOURCE to 1. This is incompatible with the new default mode, so
-# "-std=c89" compiler option:
+# we test for that and force the "-std=c89" compiler option:
 AC_MSG_CHECKING([if we need to force back C standard to C89])
 AC_COMPILE_IFELSE(
    [AC_LANG_PROGRAM([
@@ -133,23 +151,17 @@ AC_COMPILE_IFELSE(
    CFLAGS="$CFLAGS -std=c89"
 ])
 
-# Checks for header files.
+# Checks for structures and compiler characteristics.
-AC_HEADER_STDC
-
-# Checks for typedefs, structures, and compiler characteristics.
-AC_C_CONST
-AC_TYPE_SIZE_T
 AC_STRUCT_TM
 AC_C_RESTRICT
 
 # Checks for library functions.
-AC_FUNC_STRTOD
+AC_CHECK_FUNCS([pow], ,
-AC_CHECK_FUNCS([memset], , AC_MSG_ERROR(memset not found in libc))
+  [AC_CHECK_LIB([m], [pow], , [AC_MSG_ERROR([cannot find pow])])])
-AC_CHECK_FUNCS([pow], , AC_CHECK_LIB(m, pow, , AC_MSG_ERROR(cannot find pow)) )
 
-# Some later POSIX 1003.1 functions are required for test programs, failure here
+# Some later POSIX 1003.1 functions are required for test programs, failure
-# is soft (the corresponding test program is not built).
+# here is soft (the corresponding test program is not built).
-AC_CHECK_FUNC([clock_gettime],,[AC_MSG_WARN([not building timepng])])
+AC_CHECK_FUNC([clock_gettime], , [AC_MSG_WARN([not building timepng])])
 AM_CONDITIONAL([HAVE_CLOCK_GETTIME], [test "$ac_cv_func_clock_gettime" = "yes"])
 
 AC_ARG_WITH(zlib-prefix,
@@ -157,8 +169,9 @@ AC_ARG_WITH(zlib-prefix,
       [prefix that may have been used in installed zlib]),
       [ZPREFIX=${withval}],
       [ZPREFIX='z_'])
-AC_CHECK_LIB(z, zlibVersion, ,
+AC_CHECK_LIB([z], [zlibVersion], ,
-    AC_CHECK_LIB(z, ${ZPREFIX}zlibVersion, , AC_MSG_ERROR(zlib not installed)))
+  [AC_CHECK_LIB([z], [${ZPREFIX}zlibVersion], ,
+     [AC_MSG_ERROR([zlib not installed])])])
 
 # The following is for pngvalid, to ensure it catches FP errors even on
 # platforms that don't enable FP exceptions, the function appears in the math
@@ -297,9 +310,72 @@ AC_ARG_ENABLE([unversioned-libpng-config],
 AM_CONDITIONAL([DO_INSTALL_LIBPNG_CONFIG],
    [test "$enable_unversioned_libpng_config" != "no"])
 
-# HOST SPECIFIC OPTIONS
+# HOST-SPECIFIC OPTIONS
 # =====================
 #
+# DEFAULT
+# =======
+#
+AC_ARG_ENABLE([hardware-optimizations],
+   AS_HELP_STRING([[[--enable-hardware-optimizations]]],
+      [Enable hardware optimizations: =no/off, yes/on:]),
+   [case "$enableval" in
+      no|off)
+         # disable hardware optimization on all systems:
+         enable_arm_neon=no
+         AC_DEFINE([PNG_ARM_NEON_OPT], [0],
+           [Disable ARM_NEON optimizations])
+         enable_mips_msa=no
+         AC_DEFINE([PNG_MIPS_MSA_OPT], [0],
+           [Disable MIPS_MSA optimizations])
+         enable_mips_mmi=no
+         AC_DEFINE([PNG_MIPS_MMI_OPT], [0],
+           [Disable MIPS_MMI optimizations])
+         enable_powerpc_vsx=no
+         AC_DEFINE([PNG_POWERPC_VSX_OPT], [0],
+           [Disable POWERPC VSX optimizations])
+         enable_intel_sse=no
+         AC_DEFINE([PNG_INTEL_SSE_OPT], [0],
+           [Disable INTEL_SSE optimizations])
+         enable_loongarch_lsx=no
+         AC_DEFINE([PNG_LOONGARCH_LSX_OPT], [0],
+           [Disable LOONGARCH_LSX optimizations])
+         ;;
+      *)
+         # allow enabling hardware optimization on any system:
+         case "$host_cpu" in
+            arm*|aarch64*)
+              enable_arm_neon=yes
+              AC_DEFINE([PNG_ARM_NEON_OPT], [2],
+                [Enable ARM_NEON optimizations])
+              ;;
+            mipsel*|mips64el*)
+              enable_mips_mmi=yes
+              enable_mips_msa=yes
+              AC_DEFINE([PNG_MIPS_MMI_OPT], [1],
+                [Enable MIPS_MMI optimizations])
+              AC_DEFINE([PNG_MIPS_MSA_OPT], [2],
+                [Enable MIPS_MSA optimizations])
+              ;;
+            i?86|x86_64)
+              enable_intel_sse=yes
+              AC_DEFINE([PNG_INTEL_SSE_OPT], [1],
+                [Enable Intel SSE optimizations])
+              ;;
+            powerpc*|ppc64*)
+              enable_powerpc_vsx=yes
+              AC_DEFINE([PNG_POWERPC_VSX_OPT], [2],
+                [Enable POWERPC VSX optimizations])
+              ;;
+            loongarch*)
+              enable_loongarch_lsx=yes
+              AC_DEFINE([PNG_LOONGARCH_LSX_OPT], [1],
+                [Enable LOONGARCH_LSX optimizations])
+              ;;
+         esac
+         ;;
+   esac])
+
 # ARM
 # ===
 #
@@ -318,7 +394,7 @@ AC_ARG_ENABLE([arm-neon],
          AC_DEFINE([PNG_ARM_NEON_OPT], [0],
                    [Disable ARM Neon optimizations])
          # Prevent inclusion of the assembler files below:
-         enable_arm_neon=no;;
+         enable_arm_neon=no ;;
       check)
          AC_DEFINE([PNG_ARM_NEON_CHECK_SUPPORTED], [],
                    [Check for ARM Neon support at run-time]);;
@@ -335,19 +411,19 @@ AC_ARG_ENABLE([arm-neon],
          AC_MSG_ERROR([--enable-arm-neon=${enable_arm_neon}: invalid value])
    esac])
 
-# Add ARM specific files to all builds where the host_cpu is arm ('arm*') or
+# Add ARM-specific files to all builds where $host_cpu is arm ('arm*') or
-# where ARM optimizations were explicitly requested (this allows a fallback if a
+# where ARM optimizations were explicitly requested (this allows a fallback
-# future host CPU does not match 'arm*')
+# if a future host CPU does not match 'arm*')
 
 AM_CONDITIONAL([PNG_ARM_NEON],
    [test "$enable_arm_neon" != 'no' &&
     case "$host_cpu" in
-      arm*|aarch64*) :;;
+      arm*|aarch64*) : ;;
-      *)    test "$enable_arm_neon" != '';;
+      *)    test "$enable_arm_neon" != '' ;;
     esac])
 
 # MIPS
-# ===
+# ====
 #
 # MIPS MSA (SIMD) support.
 
@@ -364,7 +440,7 @@ AC_ARG_ENABLE([mips-msa],
          AC_DEFINE([PNG_MIPS_MSA_OPT], [0],
                    [Disable MIPS MSA optimizations])
          # Prevent inclusion of the assembler files below:
-         enable_mips_msa=no;;
+         enable_mips_msa=no ;;
       check)
          AC_DEFINE([PNG_MIPS_MSA_CHECK_SUPPORTED], [],
                    [Check for MIPS MSA support at run-time]);;
@@ -381,16 +457,206 @@ AC_ARG_ENABLE([mips-msa],
          AC_MSG_ERROR([--enable-mips-msa=${enable_mips_msa}: invalid value])
    esac])
 
-# Add MIPS specific files to all builds where the host_cpu is mips ('mips*') or
+# Add MIPS-specific files to all builds where $host_cpu is mips ('mips*') or
-# where MIPS optimizations were explicitly requested (this allows a fallback if a
+# where MIPS optimizations were explicitly requested (this allows a fallback
-# future host CPU does not match 'mips*')
+# if a future host CPU does not match 'mips*')
 
 AM_CONDITIONAL([PNG_MIPS_MSA],
    [test "$enable_mips_msa" != 'no' &&
+    case "$host_cpu" in
+      mipsel*|mips64el*) : ;;
+    esac])
+
+# MIPS
+# ===
+#
+# MIPS MMI (SIMD) support.
+
+AC_ARG_ENABLE([mips-mmi],
+   AS_HELP_STRING([[[--enable-mips-mmi]]],
+      [Enable MIPS MMI optimizations: =no/off, check, api, yes/on:]
+      [no/off: disable the optimizations; check: use internal checking code]
+      [(deprecated and poorly supported); 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 "$enableval" in
+      no|off)
+         # disable the default enabling on __mips_mmi systems:
+         AC_DEFINE([PNG_MIPS_MMI_OPT], [0],
+                   [Disable MIPS MMI optimizations])
+         # Prevent inclusion of the assembler files below:
+         enable_mips_mmi=no;;
+      check)
+         AC_DEFINE([PNG_MIPS_MMI_CHECK_SUPPORTED], [],
+                   [Check for MIPS MMI support at run-time]);;
+      api)
+         AC_DEFINE([PNG_MIPS_MMI_API_SUPPORTED], [],
+                   [Turn on MIPS MMI optimizations at run-time]);;
+      yes|on)
+         AC_DEFINE([PNG_MIPS_MMI_OPT], [1],
+                   [Enable MIPS MMI optimizations])
+         AC_MSG_WARN([--enable-mips-mmi: please specify 'check' or 'api', if]
+            [you want the optimizations unconditionally pass '-mloongson-mmi -march=loongson3a']
+            [to the compiler.]);;
+      *)
+         AC_MSG_ERROR([--enable-mips-mmi=${enable_mips_mmi}: invalid value])
+   esac])
+
+# Add MIPS specific files to all builds where the host_cpu is mips ('mips*') or
+# where MIPS optimizations were explicitly requested (this allows a fallback if a
+# future host CPU does not match 'mips*')
+
+AM_CONDITIONAL([PNG_MIPS_MMI],
+   [test "$enable_mips_mmi" != 'no' &&
     case "$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 $host_cpu is Intel ('x86*') or
+# where Intel optimizations were explicitly requested (this allows a fallback
+# if a future host CPU does not match 'x86*')
+AM_CONDITIONAL([PNG_INTEL_SSE],
+   [test "$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 $host_cpu is powerpc('powerpc*')
+# or where PowerPC optimizations were explicitly requested (this allows a fallback
+# if a future host CPU does not match 'powerpc*')
+
+AM_CONDITIONAL([PNG_POWERPC_VSX],
+   [test "$enable_powerpc_vsx" != 'no' &&
+    case "$host_cpu" in
+      powerpc*|ppc64*) : ;;
+    esac])
+
+# LOONGARCH
+# ===
+#
+# LOONGARCH LSX (SIMD) support
+
+if test "$LSX_CFLAGS" = ''; then
+    LSX_CFLAGS="-mlsx"
+fi
+
+compiler_support_loongarch_lsx=no
+AC_MSG_CHECKING(whether to use loongarch LSX intrinsics)
+save_CFLAGS=$CFLAGS
+CFLAGS="$CFLAGS $LSX_CFLAGS"
+AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
+#include<lsxintrin.h>
+int main(){
+    __m128i a, b, c;
+    a = __lsx_vadd_w(b, c);
+    return 0;
+}]])],compiler_support_loongarch_lsx=yes)
+CFLAGS=$save_CFLAGS
+AC_MSG_RESULT($compiler_support_loongarch_lsx)
+
+AC_ARG_ENABLE([loongarch-lsx],
+   AS_HELP_STRING([[[--enable-loongarch-lsx]]],
+      [Enable LOONGARCH LSX optimizations: =no/off, yes/on:]
+      [no/off: disable the optimizations;]
+      [yes/on: turn on unconditionally.]
+      [If not specified: determined by the compiler.]),
+   [case "$enableval" in
+      no|off)
+         # disable the default enabling on __loongarch_simd systems:
+         AC_DEFINE([PNG_LOONGARCH_LSX_OPT], [0],
+                   [Disable LOONGARCH LSX optimizations])
+         # Prevent inclusion of the assembler files below:
+         enable_loongarch_lsx=no;;
+      yes|on)
+         AC_DEFINE([PNG_LOONGARCH_LSX_OPT], [1],
+                   [Enable LOONGARCH LSX optimizations])
+         ;;
+      *)
+         AC_MSG_ERROR([--enable-loongarch-lsx=${enable_loongarch_lsx}: invalid value])
+   esac])
+
+if test "$enable_loongarch_lsx" != 'no'; then
+   if test $compiler_support_loongarch_lsx = yes; then
+      AC_DEFINE([PNG_LOONGARCH_LSX_OPT], [1], [Enable LOONGARCH LSX optimizations])
+   else
+      AC_MSG_WARN([Compiler does not support loongarch LSX.])
+   fi
+fi
+
+# Add LOONGARCH specific files to all builds where the host_cpu is loongarch ('loongarch*') or
+# where LOONGARCH optimizations were explicitly requested (this allows a fallback if a
+# future host CPU does not match 'loongarch*')
+
+AM_CONDITIONAL([PNG_LOONGARCH_LSX],
+   [test "$enable_loongarch_lsx" != 'no' && test $compiler_support_loongarch_lsx = yes &&
+    case "$host_cpu" in
+      loongarch*) :;;
+      *)    test "$enable_loongarch_lsx" != '';;
+    esac])
+
 AC_MSG_NOTICE([[Extra options for compiler: $PNG_COPTS]])
 
 # Config files, substituting as above

contrib/arm-neon/android-ndk.c

@@ -2,7 +2,6 @@
  *
  * Copyright (c) 2014 Glenn Randers-Pehrson
  * Written by John Bowler, 2014.
- * Last changed in libpng 1.6.10 [March 6, 2014]
  *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
@@ -17,13 +16,14 @@
  *
  * Documentation:
  *    http://www.kandroid.org/ndk/docs/CPU-ARM-NEON.html
- *    http://code.google.com/p/android/issues/detail?id=49065
+ *    https://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
  * has been compiled only, not linked: no version of the library has been found,
  * only the header files exist in the NDK.
  */
+
 #include <cpu-features.h>
 
 static int

contrib/arm-neon/linux-auxv.c

@@ -2,7 +2,6 @@
  *
  * Copyright (c) 2014 Glenn Randers-Pehrson
  * Written by Mans Rullgard, 2011.
- * Last changed in libpng 1.6.10 [March 6, 2014]
  *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
@@ -22,6 +21,7 @@
  * This generic __linux__ implementation requires reading /proc/self/auxv and
  * looking at each element for one that records NEON capabilities.
  */
+
 #include <unistd.h> /* for POSIX 1003.1 */
 #include <errno.h>  /* for EINTR */
 

contrib/arm-neon/linux.c

@@ -1,8 +1,7 @@
 /* contrib/arm-neon/linux.c
  *
- * Copyright (c) 2014 Glenn Randers-Pehrson
+ * Copyright (c) 2014, 2017 Glenn Randers-Pehrson
- * Written by John Bowler, 2014.
+ * Written by John Bowler, 2014, 2017.
- * Last changed in libpng 1.6.16 [December 22, 2014]
  *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
@@ -19,6 +18,7 @@
  * 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>
 
 static int
@@ -62,7 +62,7 @@ png_have_neon(png_structp png_ptr)
 
                counter=0;
                state = Feature;
-               /* FALL THROUGH */
+               /* FALLTHROUGH */
 
             case Feature:
                /* Match 'FEATURE', ASCII case insensitive. */
@@ -75,7 +75,7 @@ png_have_neon(png_structp png_ptr)
 
                /* did not match 'feature' */
                state = SkipLine;
-               /* FALL THROUGH */
+               /* FALLTHROUGH */
 
             case SkipLine:
             skipLine:
@@ -110,7 +110,7 @@ png_have_neon(png_structp png_ptr)
 
                state = Neon;
                counter = 0;
-               /* FALL THROUGH */
+               /* FALLTHROUGH */
 
             case Neon:
                /* Look for 'neon' tag */
@@ -122,7 +122,7 @@ png_have_neon(png_structp png_ptr)
                }
 
                state = SkipTag;
-               /* FALL THROUGH */
+               /* FALLTHROUGH */
 
             case SkipTag:
                /* Skip non-space characters */

contrib/conftest/pngcp.dfa

@@ -33,7 +33,7 @@ option WRITE_16BIT on
 option WRITE_FILTER on
 
 # pngcp needs this to preserve unknown chunks, switching all these on means that
-# pngcp can work without explicit known chunk reading suppport
+# pngcp can work without explicit known chunk reading support
 option UNKNOWN_CHUNKS on
 option SET_UNKNOWN_CHUNKS on
 option HANDLE_AS_UNKNOWN on
@@ -52,6 +52,6 @@ option TEXT on
 option USER_LIMITS on
 option SET_USER_LIMITS on
 
-# these are are just required for specific customizations
+# these are just required for specific customizations
 option WRITE_CUSTOMIZE_ZTXT_COMPRESSION on
 option WRITE_CUSTOMIZE_COMPRESSION on

contrib/examples/iccfrompng.c

@@ -10,7 +10,7 @@
  * without processing the image.  Notice that some header information may occur
  * after the image data. Textual data and comments are an example; the approach
  * in this file won't work reliably for such data because it only looks for the
- * information in the section of the file that preceeds the image data.
+ * information in the section of the file that precedes the image data.
  *
  * Compile and link against libpng and zlib, plus anything else required on the
  * system you use.

contrib/examples/pngpixel.c

@@ -42,7 +42,7 @@ component(png_const_bytep row, png_uint_32 x, unsigned int c,
    png_uint_32 bit_offset_hi = bit_depth * ((x >> 6) * channels);
    png_uint_32 bit_offset_lo = bit_depth * ((x & 0x3f) * channels + c);
 
-   row = (png_const_bytep)(((PNG_CONST png_byte (*)[8])row) + bit_offset_hi);
+   row = (png_const_bytep)(((const png_byte (*)[8])row) + bit_offset_hi);
    row += bit_offset_lo >> 3;
    bit_offset_lo &= 0x07;
 
@@ -73,7 +73,7 @@ static void
 print_pixel(png_structp png_ptr, png_infop info_ptr, png_const_bytep row,
    png_uint_32 x)
 {
-   PNG_CONST unsigned int bit_depth = png_get_bit_depth(png_ptr, info_ptr);
+   unsigned int bit_depth = png_get_bit_depth(png_ptr, info_ptr);
 
    switch (png_get_color_type(png_ptr, info_ptr))
    {
@@ -87,7 +87,7 @@ print_pixel(png_structp png_ptr, png_infop info_ptr, png_const_bytep row,
        */
       case PNG_COLOR_TYPE_PALETTE:
          {
-            PNG_CONST int index = component(row, x, 0, bit_depth, 1);
+            int index = component(row, x, 0, bit_depth, 1);
             png_colorp palette = NULL;
             int num_palette = 0;
 

contrib/examples/pngtopng.c

@@ -1,6 +1,6 @@
 /*- pngtopng
  *
- * COPYRIGHT: Written by John Cunningham Bowler, 2011.
+ * COPYRIGHT: Written by John Cunningham Bowler, 2011, 2017.
  * 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.
@@ -59,28 +59,29 @@ int main(int argc, const char **argv)
                else
                   fprintf(stderr, "pngtopng: write %s: %s\n", argv[2],
                       image.message);
+            }
+
+            else
+               fprintf(stderr, "pngtopng: read %s: %s\n", argv[1],
+                   image.message);
 
             free(buffer);
          }
 
          else
          {
-               fprintf(stderr, "pngtopng: read %s: %s\n", argv[1],
+            fprintf(stderr, "pngtopng: out of memory: %lu bytes\n",
-                   image.message);
+               (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.
+             * 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
-            fprintf(stderr, "pngtopng: out of memory: %lu bytes\n",
-               (unsigned long)PNG_IMAGE_SIZE(image));
-      }
-
       else
          /* Failed to read the first argument: */
          fprintf(stderr, "pngtopng: %s: %s\n", argv[1], image.message);

contrib/gregbook/README

@@ -55,7 +55,7 @@ mation and links to the latest version of the source code, and Chapters
 13-15 of the book for detailed discussion of the three programs.
 
 Greg Roelofs
-http://pobox.com/~newt/greg_contact.html
+https://pobox.com/~newt/greg_contact.html
 16 March 2008
 
 
@@ -63,7 +63,7 @@ BUILD INSTRUCTIONS
 
  - Prerequisites (in order of compilation):
 
-      - zlib            http://zlib.net/
+      - zlib            https://zlib.net/
       - libpng          http://www.libpng.org/pub/png/libpng.html
       - pngbook         http://www.libpng.org/pub/png/book/sources.html
 

contrib/gregbook/readpng.c

@@ -4,7 +4,7 @@
 
   ---------------------------------------------------------------------------
 
-      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
+      Copyright (c) 1998-2007,2017 Greg Roelofs.  All rights reserved.
 
       This software is provided "as is," without warranty of any kind,
       express or implied.  In no event shall the author or contributors
@@ -264,6 +264,12 @@ uch *readpng_get_image(double display_exponent, int *pChannels, ulg *pRowbytes)
     *pRowbytes = rowbytes = png_get_rowbytes(png_ptr, info_ptr);
     *pChannels = (int)png_get_channels(png_ptr, info_ptr);
 
+    /* Guard against integer overflow */
+    if (height > ((size_t)(-1))/rowbytes) {
+        fprintf(stderr, "readpng:  image_data buffer would be too large\n",
+        return NULL;
+    }
+
     if ((image_data = (uch *)malloc(rowbytes*height)) == NULL) {
         png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
         return NULL;

contrib/gregbook/readpng2.c

@@ -55,6 +55,7 @@
 
    Changelog:
      2015-11-12 - Check return value of png_get_bKGD() (Glenn R-P)
+     2017-04-22 - Guard against integer overflow (Glenn R-P)
 
   ---------------------------------------------------------------------------*/
 
@@ -145,7 +146,7 @@ int readpng2_init(mainprog_info *mainprog_ptr)
         /* These byte strings were copied from png.h.  If a future version
          * of readpng2.c recognizes more chunks, add them to this list.
          */
-        static PNG_CONST png_byte chunks_to_process[] = {
+        static const png_byte chunks_to_process[] = {
             98,  75,  71,  68, '\0',  /* bKGD */
            103,  65,  77,  65, '\0',  /* gAMA */
            115,  82,  71,  66, '\0',  /* sRGB */

contrib/gregbook/readppm.c

@@ -9,7 +9,7 @@
 
   ---------------------------------------------------------------------------
 
-      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
+      Copyright (c) 1998-2007,2017 Greg Roelofs.  All rights reserved.
 
       This software is provided "as is," without warranty of any kind,
       express or implied.  In no event shall the author or contributors
@@ -154,12 +154,17 @@ uch *readpng_get_image(double display_exponent, int *pChannels, ulg *pRowbytes)
     *pRowbytes = rowbytes = channels*width;
     *pChannels = channels;
 
-    if ((image_data = (uch *)malloc(rowbytes*height)) == NULL) {
+    Trace((stderr, "readpng_get_image:  rowbytes = %ld, height = %ld\n", rowbytes, height));
+
+    /* Guard against integer overflow */
+    if (height > ((size_t)(-1))/rowbytes) {
+        fprintf(stderr, PROGNAME ":  image_data buffer would be too large\n",
         return NULL;
     }
 
-    Trace((stderr, "readpng_get_image:  rowbytes = %ld, height = %ld\n", rowbytes, height));
+    if ((image_data = (uch *)malloc(rowbytes*height)) == NULL) {
-
+        return NULL;
+    }
 
     /* now we can go ahead and just read the whole image */
 

contrib/gregbook/rpng-win.c

@@ -24,10 +24,11 @@
     - 1.10:  enabled "message window"/console (thanks to David Geldreich)
     - 2.00:  dual-licensed (added GNU GPL)
     - 2.01:  fixed improper display of usage screen on PNG error(s)
+    - 2.02:  check for integer overflow (Glenn R-P)
 
   ---------------------------------------------------------------------------
 
-      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
+      Copyright (c) 1998-2008, 2017 Greg Roelofs.  All rights reserved.
 
       This software is provided "as is," without warranty of any kind,
       express or implied.  In no event shall the author or contributors
@@ -496,6 +497,12 @@ static int rpng_win_create_window(HINSTANCE hInst, int showmode)
 
     wimage_rowbytes = ((3*image_width + 3L) >> 2) << 2;
 
+    /* Guard against integer overflow */
+    if (image_height > ((size_t)(-1))/wimage_rowbytes) {
+        fprintf(stderr, PROGNAME ":  image_data buffer would be too large\n");
+        return 4;   /* fail */
+    }
+
     if (!(dib = (uch *)malloc(sizeof(BITMAPINFOHEADER) +
                               wimage_rowbytes*image_height)))
     {

contrib/gregbook/rpng-x.c

@@ -28,10 +28,11 @@
     - 2.01:  fixed improper display of usage screen on PNG error(s)
     - 2.02:  Added "void(argc);" statement to quiet pedantic compiler warnings
              about unused variable (GR-P)
+    - 2.03:  check for integer overflow (Glenn R-P)
 
   ---------------------------------------------------------------------------
 
-      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
+      Copyright (c) 1998-2008, 2017 Greg Roelofs.  All rights reserved.
 
       This software is provided "as is," without warranty of any kind,
       express or implied.  In no event shall the author or contributors

contrib/gregbook/rpng2-win.c

@@ -33,12 +33,11 @@
     - 2.02:  fixed improper display of usage screen on PNG error(s); fixed
               unexpected-EOF and file-read-error cases
     - 2.03:  removed runtime MMX-enabling/disabling and obsolete -mmx* options
-    - 2.04:
+    - 2.04:  check for integer overflow (Glenn R-P)
-             (GR-P)
 
   ---------------------------------------------------------------------------
 
-      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
+      Copyright (c) 1998-2008, 2017 Greg Roelofs.  All rights reserved.
 
       This software is provided "as is," without warranty of any kind,
       express or implied.  In no event shall the author or contributors
@@ -650,6 +649,13 @@ static void rpng2_win_init()
     Trace((stderr, "  width  = %ld\n", rpng2_info.width))
     Trace((stderr, "  height = %ld\n", rpng2_info.height))
 
+    /* Guard against integer overflow */
+    if (rpng2_info.height > ((size_t)(-1))/rowbytes) {
+        fprintf(stderr, PROGNAME ":  image_data buffer would be too large\n",
+        readpng2_cleanup(&rpng2_info);
+        return;
+    }
+
     rpng2_info.image_data = (uch *)malloc(rowbytes * rpng2_info.height);
     if (!rpng2_info.image_data) {
         readpng2_cleanup(&rpng2_info);

contrib/gregbook/rpng2-x.c

@@ -44,9 +44,11 @@
     - 2.04:  Added "void(foo);" statements to quiet pedantic compiler warnings
              about unused variables (GR-P)
     - 2.05:  Use nanosleep() instead of usleep(), which is deprecated (GR-P).
+    - 2.06:  check for integer overflow (Glenn R-P)
   ---------------------------------------------------------------------------
 
-      Copyright (c) 1998-2010, 2014-2015 Greg Roelofs.  All rights reserved.
+      Copyright (c) 1998-2010, 2014-2015, 2017 Greg Roelofs.  All rights
+      reserved.
 
       This software is provided "as is," without warranty of any kind,
       express or implied.  In no event shall the author or contributors
@@ -780,6 +782,13 @@ static void rpng2_x_init(void)
     Trace((stderr, "  width  = %ld\n", rpng2_info.width))
     Trace((stderr, "  height = %ld\n", rpng2_info.height))
 
+    /* Guard against integer overflow */
+    if (rpng2_info.height > ((size_t)(-1))/rpng2_info.rowbytes) {
+        fprintf(stderr, PROGNAME ":  image_data buffer would be too large\n");
+        readpng2_cleanup(&rpng2_info);
+        return;
+    }
+
     rpng2_info.image_data = (uch *)malloc(rowbytes * rpng2_info.height);
     if (!rpng2_info.image_data) {
         readpng2_cleanup(&rpng2_info);

contrib/gregbook/wpng.c

@@ -29,6 +29,7 @@
     - 1.04:  fixed DOS/OS2/Win32 detection, including partial Cygwin fix
               (see http://home.att.net/~perlspinr/diffs/GregBook_cygwin.diff)
     - 2.00:  dual-licensed (added GNU GPL)
+    - 2.01:  check for integer overflow (Glenn R-P)
 
         [REPORTED BUG (win32 only):  "contrib/gregbook/wpng.c - cmd line
          dose not work!  In order to do something useful I needed to redirect
@@ -38,7 +39,7 @@
 
   ---------------------------------------------------------------------------
 
-      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
+      Copyright (c) 1998-2007, 2017 Greg Roelofs.  All rights reserved.
 
       This software is provided "as is," without warranty of any kind,
       express or implied.  In no event shall the author or contributors
@@ -702,7 +703,18 @@ int main(int argc, char **argv)
     if (wpng_info.interlaced) {
         long i;
         ulg bytes;
-        ulg image_bytes = rowbytes * wpng_info.height;   /* overflow? */
+        ulg image_bytes;
+
+        /* Guard against integer overflow */
+        if (wpng_info_height > ((size_t)(-1)/rowbytes ||
+            wpng_info_height > ((ulg)(-1)/rowbytes) {
+            fprintf(stderr, PROGNAME ":  image_data buffer too large\n");
+            writepng_cleanup(&wpng_info);
+            wpng_cleanup();
+            exit(5);
+        }
+
+        image_bytes = rowbytes * wpng_info.height;
 
         wpng_info.image_data = (uch *)malloc(image_bytes);
         wpng_info.row_pointers = (uch **)malloc(wpng_info.height*sizeof(uch *));

contrib/gregbook/writepng.c

@@ -4,7 +4,7 @@
 
   ---------------------------------------------------------------------------
 
-      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
+      Copyright (c) 1998-2007, 2017 Greg Roelofs.  All rights reserved.
 
       This software is provided "as is," without warranty of any kind,
       express or implied.  In no event shall the author or contributors

contrib/intel/INSTALL

@@ -1,158 +0,0 @@
-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----------------

contrib/intel/intel_sse.patch

@@ -1,190 +0,0 @@
-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
-@@ -1251,16 +1287,31 @@ 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
-@@ -1986,16 +2037,21 @@ 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"

contrib/libtests/gentests.sh

@@ -2,8 +2,6 @@
 #
 # Copyright (c) 2013 John Cunningham Bowler
 #
-# Last changed in libpng 1.6.0 [February 14, 2013]
-#
 # This code is released under the libpng license.
 # For conditions of distribution and use, see the disclaimer
 # and license in png.h

contrib/libtests/makepng.c

@@ -3,8 +3,6 @@
 /* Copyright: */
 #define COPYRIGHT "\251 2013,2015 John Cunningham Bowler"
 /*
- * Last changed in libpng 1.6.20 [November 24, 2015]
- *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
  * and license in png.h
@@ -299,7 +297,9 @@ generate_palette(png_colorp palette, png_bytep trans, int bit_depth,
             unsigned int x, y;
             volatile unsigned int ip = 0;
 
-            for (x=0; x<size; ++x) for (y=0; y<size; ++y)
+            for (x=0; x<size; ++x)
+            {
+               for (y=0; y<size; ++y)
                {
                   ip = x + (size * y);
 
@@ -319,6 +319,7 @@ generate_palette(png_colorp palette, png_bytep trans, int bit_depth,
                      xyinterp(x, y,   0, 102, 204, 255),
                      gamma_table);
                }
+            }
 
             return ip+1;
          }
@@ -396,7 +397,7 @@ generate_row(png_bytep row, size_t rowbytes, unsigned int y, int color_type,
       image_size_of_type(color_type, bit_depth, colors, small)-1;
    png_uint_32 depth_max = (1U << bit_depth)-1; /* up to 65536 */
 
-   if (colors[0] == 0) if (small)
+   if (colors[0] == 0 && small)
    {
       unsigned int pixel_depth = pixel_depth_of_type(color_type, bit_depth);
 
@@ -495,7 +496,7 @@ generate_row(png_bytep row, size_t rowbytes, unsigned int y, int color_type,
          case 32:
          case 48:
          case 64:
-            /* The rows are filled by an alogorithm similar to the above, in the
+            /* The rows are filled by an algorithm similar to the above, in the
              * first row pixel bytes are all equal, increasing from 0 by 1 for
              * each pixel.  In the second row the bytes within a pixel are
              * incremented 1,3,5,7,... from the previous row byte.  Using an odd
@@ -661,7 +662,7 @@ generate_row(png_bytep row, size_t rowbytes, unsigned int y, int color_type,
       {
          case 1:
             {
-               const png_uint_32 luma = colors[1];
+               png_uint_32 luma = colors[1];
                png_uint_32 x;
 
                for (x=0; x<=size_max; ++x)
@@ -672,8 +673,8 @@ generate_row(png_bytep row, size_t rowbytes, unsigned int y, int color_type,
 
          case 2:
             {
-               const png_uint_32 luma = colors[1];
+               png_uint_32 luma = colors[1];
-               const png_uint_32 alpha = colors[2];
+               png_uint_32 alpha = colors[2];
                png_uint_32 x;
 
                for (x=0; x<size_max; ++x)
@@ -688,9 +689,9 @@ generate_row(png_bytep row, size_t rowbytes, unsigned int y, int color_type,
 
          case 3:
             {
-               const png_uint_32 red = colors[1];
+               png_uint_32 red = colors[1];
-               const png_uint_32 green = colors[2];
+               png_uint_32 green = colors[2];
-               const png_uint_32 blue = colors[3];
+               png_uint_32 blue = colors[3];
                png_uint_32 x;
 
                for (x=0; x<=size_max; ++x)
@@ -707,10 +708,10 @@ generate_row(png_bytep row, size_t rowbytes, unsigned int y, int color_type,
 
          case 4:
             {
-               const png_uint_32 red = colors[1];
+               png_uint_32 red = colors[1];
-               const png_uint_32 green = colors[2];
+               png_uint_32 green = colors[2];
-               const png_uint_32 blue = colors[3];
+               png_uint_32 blue = colors[3];
-               const png_uint_32 alpha = colors[4];
+               png_uint_32 alpha = colors[4];
                png_uint_32 x;
 
                for (x=0; x<=size_max; ++x)
@@ -812,7 +813,7 @@ write_png(const char **name, FILE *fp, int color_type, int bit_depth,
       png_error(png_ptr, "OOM allocating info structure");
 
    {
-      const unsigned int size =
+      unsigned int size =
          image_size_of_type(color_type, bit_depth, colors, small);
       unsigned int ysize;
       png_fixed_point real_gamma = 45455; /* For sRGB */
@@ -824,7 +825,7 @@ write_png(const char **name, FILE *fp, int color_type, int bit_depth,
        */
       if (small)
       {
-         const unsigned int pixel_depth =
+         unsigned int pixel_depth =
             pixel_depth_of_type(color_type, bit_depth);
 
          if (pixel_depth <= 8U)
@@ -858,11 +859,14 @@ write_png(const char **name, FILE *fp, int color_type, int bit_depth,
       {
          unsigned int i;
 
-         if (real_gamma == 45455) for (i=0; i<256; ++i)
+         if (real_gamma == 45455)
+         {
+            for (i=0; i<256; ++i)
             {
                gamma_table[i] = (png_byte)i;
                conv = 1.;
             }
+         }
 
          else
          {
@@ -950,7 +954,7 @@ write_png(const char **name, FILE *fp, int color_type, int bit_depth,
             int passes = 1;
 #        endif /* !WRITE_INTERLACING */
          int pass;
-         png_size_t rowbytes = png_get_rowbytes(png_ptr, info_ptr);
+         size_t rowbytes = png_get_rowbytes(png_ptr, info_ptr);
 
          row = malloc(rowbytes);
 
@@ -1094,7 +1098,7 @@ load_file(png_const_charp name, png_bytepp result)
    return 0;
 }
 
-static png_size_t
+static size_t
 load_fake(png_charp param, png_bytepp profile)
 {
    char *endptr = NULL;
@@ -1164,7 +1168,7 @@ insert_iCCP(png_structp png_ptr, png_infop info_ptr, int nparams,
    {
       case '<':
          {
-            png_size_t filelen = load_file(params[1]+1, &profile);
+            size_t filelen = load_file(params[1]+1, &profile);
             if (filelen > 0xfffffffc) /* Maximum profile length */
             {
                fprintf(stderr, "%s: file too long (%lu) for an ICC profile\n",
@@ -1179,7 +1183,7 @@ insert_iCCP(png_structp png_ptr, png_infop info_ptr, int nparams,
       case '0': case '1': case '2': case '3': case '4':
       case '5': case '6': case '7': case '8': case '9':
          {
-            png_size_t fake_len = load_fake(params[1], &profile);
+            size_t fake_len = load_fake(params[1], &profile);
 
             if (fake_len > 0) /* else a simple parameter */
             {
@@ -1274,7 +1278,7 @@ set_text(png_structp png_ptr, png_infop info_ptr, png_textp text,
       case '5': case '6': case '7': case '8': case '9':
          {
             png_bytep data = NULL;
-            png_size_t fake_len = load_fake(param, &data);
+            size_t fake_len = load_fake(param, &data);
 
             if (fake_len > 0) /* else a simple parameter */
             {
@@ -1378,10 +1382,10 @@ static void
 insert_sBIT(png_structp png_ptr, png_infop info_ptr, int nparams,
       png_charpp params)
 {
-   const int ct = png_get_color_type(png_ptr, info_ptr);
+   int ct = png_get_color_type(png_ptr, info_ptr);
-   const int c = (ct & PNG_COLOR_MASK_COLOR ? 3 : 1) +
+   int c = (ct & PNG_COLOR_MASK_COLOR ? 3 : 1) +
       (ct & PNG_COLOR_MASK_ALPHA ? 1 : 0);
-   const unsigned int maxval =
+   unsigned int maxval =
       ct & PNG_COLOR_MASK_PALETTE ? 8U : png_get_bit_depth(png_ptr, info_ptr);
    png_color_8 sBIT;
 
@@ -1430,12 +1434,15 @@ find_parameters(png_const_charp what, png_charp param, png_charp *list,
    for (i=0; *param && i<nparams; ++i)
    {
       list[i] = param;
-      while (*++param) if (*param == '\n' || *param == ':')
+      while (*++param)
+      {
+         if (*param == '\n' || *param == ':')
          {
             *param++ = 0; /* Terminate last parameter */
             break;        /* And start a new one. */
          }
       }
+   }
 
    if (*param)
    {
@@ -1856,7 +1863,7 @@ main(int argc, char **argv)
 
    /* Check the colors */
    {
-      const unsigned int lim = (color_type == PNG_COLOR_TYPE_PALETTE ? 255U :
+      unsigned int lim = (color_type == PNG_COLOR_TYPE_PALETTE ? 255U :
          (1U<<bit_depth)-1);
       unsigned int i;
 
@@ -1869,7 +1876,7 @@ main(int argc, char **argv)
          }
    }
 
-   /* small and colors are incomparible (will probably crash if both are used at
+   /* small and colors are incompatible (will probably crash if both are used at
     * the same time!)
     */
    if (small && colors[0] != 0)

contrib/libtests/pngimage.c

@@ -1,9 +1,9 @@
+
 /* pngimage.c
  *
+ * Copyright (c) 2021 Cosmin Truta
  * Copyright (c) 2015,2016 John Cunningham Bowler
  *
- * Last changed in libpng 1.6.24 [August 4, 2016]
- *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
  * and license in png.h
@@ -12,6 +12,7 @@
  * using png_read_png and then write with png_write_png.  Test all possible
  * transforms.
  */
+
 #include <stdarg.h>
 #include <stdlib.h>
 #include <string.h>
@@ -317,11 +318,10 @@ transform_name(int t)
 
    t &= -t; /* first set bit */
 
-   for (i=0; i<TTABLE_SIZE; ++i) if (transform_info[i].name != NULL)
+   for (i=0; i<TTABLE_SIZE; ++i)
-   {
+      if (transform_info[i].name != NULL)
          if ((transform_info[i].transform & t) != 0)
             return transform_info[i].name;
-   }
 
    return "invalid transform";
 }
@@ -338,7 +338,9 @@ validate_T(void)
 {
    unsigned int i;
 
-   for (i=0; i<TTABLE_SIZE; ++i) if (transform_info[i].name != NULL)
+   for (i=0; i<TTABLE_SIZE; ++i)
+   {
+      if (transform_info[i].name != NULL)
       {
          if (transform_info[i].when & TRANSFORM_R)
             read_transforms |= transform_info[i].transform;
@@ -346,6 +348,7 @@ validate_T(void)
          if (transform_info[i].when & TRANSFORM_W)
             write_transforms |= transform_info[i].transform;
       }
+   }
 
    /* Reversible transforms are those which are supported on both read and
     * write.
@@ -551,7 +554,7 @@ struct display
    png_structp    original_pp;       /* used on the original read */
    png_infop      original_ip;       /* set by the original read */
 
-   png_size_t     original_rowbytes; /* of the original rows: */
+   size_t         original_rowbytes; /* of the original rows: */
    png_bytepp     original_rows;     /* from the original read */
 
    /* Original chunks valid */
@@ -807,7 +810,7 @@ display_cache_file(struct display *dp, const char *filename)
 
 static void
 buffer_read(struct display *dp, struct buffer *bp, png_bytep data,
-   png_size_t size)
+   size_t size)
 {
    struct buffer_list *last = bp->current;
    size_t read_count = bp->read_count;
@@ -855,7 +858,7 @@ buffer_read(struct display *dp, struct buffer *bp, png_bytep data,
 }
 
 static void PNGCBAPI
-read_function(png_structp pp, png_bytep data, png_size_t size)
+read_function(png_structp pp, png_bytep data, size_t size)
 {
    buffer_read(get_dp(pp), get_buffer(pp), data, size);
 }
@@ -927,7 +930,7 @@ update_display(struct display *dp)
    png_structp pp;
    png_infop   ip;
 
-   /* Now perform the initial read with a 0 tranform. */
+   /* Now perform the initial read with a 0 transform. */
    read_png(dp, &dp->original_file, "original read", 0/*no transform*/);
 
    /* Move the result to the 'original' fields */
@@ -962,7 +965,9 @@ update_display(struct display *dp)
       int bd = dp->bit_depth;
       unsigned int i;
 
-      for (i=0; i<TTABLE_SIZE; ++i) if (transform_info[i].name != NULL)
+      for (i=0; i<TTABLE_SIZE; ++i)
+      {
+         if (transform_info[i].name != NULL)
          {
             int transform = transform_info[i].transform;
 
@@ -978,6 +983,7 @@ update_display(struct display *dp)
             else if ((transform_info[i].when & TRANSFORM_R) != 0)
                inactive |= transform;
          }
+      }
 
       /* Some transforms appear multiple times in the table; the 'active' status
        * is the logical OR of these and the inactive status must be adjusted to
@@ -1000,8 +1006,9 @@ compare_read(struct display *dp, int applied_transforms)
    int interlace_method, compression_method, filter_method;
    const char *e = NULL;
 
-   png_get_IHDR(dp->read_pp, dp->read_ip, &width, &height, &bit_depth,
+   if (!png_get_IHDR(dp->read_pp, dp->read_ip, &width, &height, &bit_depth,
-      &color_type, &interlace_method, &compression_method, &filter_method);
+      &color_type, &interlace_method, &compression_method, &filter_method))
+      display_log(dp, LIBPNG_BUG, "png_get_IHDR failed");
 
 #  define C(item) if (item != dp->item) \
       display_log(dp, APP_WARNING, "IHDR " #item "(%lu) changed to %lu",\
@@ -1081,7 +1088,8 @@ compare_read(struct display *dp, int applied_transforms)
                size_t x;
 
                /* Find the first error */
-               for (x=0; x<rowbytes-1; ++x) if (row[x] != orig[x])
+               for (x=0; x<rowbytes-1; ++x)
+                  if (row[x] != orig[x])
                      break;
 
                display_log(dp, APP_FAIL,
@@ -1137,6 +1145,7 @@ compare_read(struct display *dp, int applied_transforms)
                display_log(dp, LIBPNG_ERROR, "invalid colour type %d",
                   color_type);
                /*NOTREACHED*/
+               memset(sig_bits, 0, sizeof(sig_bits));
                bpp = 0;
                break;
          }
@@ -1198,7 +1207,7 @@ compare_read(struct display *dp, int applied_transforms)
                sig_bits[0] = (png_byte)b;
                break;
 
-            case 4: /* Relicate twice */
+            case 4: /* Replicate twice */
                /* Value is 1, 2, 3 or 4 */
                b = 0xf & ((0xf << 4) >> sig_bits[0]);
                b |= b << 4;
@@ -1267,7 +1276,7 @@ compare_read(struct display *dp, int applied_transforms)
 #ifdef PNG_WRITE_PNG_SUPPORTED
 static void
 buffer_write(struct display *dp, struct buffer *buffer, png_bytep data,
-   png_size_t size)
+   size_t size)
    /* Generic write function used both from the write callback provided to
     * libpng and from the generic read code.
     */
@@ -1311,7 +1320,7 @@ buffer_write(struct display *dp, struct buffer *buffer, png_bytep data,
 }
 
 static void PNGCBAPI
-write_function(png_structp pp, png_bytep data, png_size_t size)
+write_function(png_structp pp, png_bytep data, size_t size)
 {
    buffer_write(get_dp(pp), get_buffer(pp), data, size);
 }
@@ -1446,7 +1455,7 @@ test_one_file(struct display *dp, const char *filename)
        * unsigned, because some transforms are negative on a 16-bit system.
        */
       unsigned int active = dp->active_transforms;
-      const int exhaustive = (dp->options & EXHAUSTIVE) != 0;
+      int exhaustive = (dp->options & EXHAUSTIVE) != 0;
       unsigned int current = first_transform(active);
       unsigned int bad_transforms = 0;
       unsigned int bad_combo = ~0U;    /* bitwise AND of failing transforms */
@@ -1572,7 +1581,7 @@ do_test(struct display *dp, const char *file)
 }
 
 int
-main(const int argc, const char * const * const argv)
+main(int argc, char **argv)
 {
    /* For each file on the command line test it with a range of transforms */
    int option_end, ilog = 0;
@@ -1674,7 +1683,7 @@ main(const int argc, const char * const * const argv)
          /* Here on any return, including failures, except user/internal issues
           */
          {
-            const int pass = (d.options & STRICT) ?
+            int pass = (d.options & STRICT) ?
                RESULT_STRICT(d.results) : RESULT_RELAXED(d.results);
 
             if (!pass)
@@ -1686,7 +1695,8 @@ main(const int argc, const char * const * const argv)
 
                printf("%s: pngimage ", pass ? "PASS" : "FAIL");
 
-               for (j=1; j<option_end; ++j) if (j != ilog)
+               for (j=1; j<option_end; ++j)
+                  if (j != ilog)
                      printf("%s ", argv[j]);
 
                printf("%s\n", d.filename);

contrib/libtests/pngstest.c

@@ -1,9 +1,8 @@
-/*-
+
- * pngstest.c
+/* pngstest.c
  *
- * Copyright (c) 2013-2016 John Cunningham Bowler
+ * Copyright (c) 2021 Cosmin Truta
- *
+ * Copyright (c) 2013-2017 John Cunningham Bowler
- * Last changed in libpng 1.6.24 [August 4, 2016]
  *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
@@ -11,8 +10,9 @@
  *
  * Test for the PNG 'simplified' APIs.
  */
+
 #define _ISOC90_SOURCE 1
-#define MALLOC_CHECK_ 2/*glibc facility: turn on debugging*/
+#define MALLOC_CHECK_ 2 /*glibc facility: turn on debugging*/
 
 #include <stddef.h>
 #include <stdlib.h>
@@ -373,7 +373,7 @@ print_opts(png_uint_32 opts)
  */
 #define FORMAT_COUNT 64
 #define FORMAT_MASK 0x3f
-static PNG_CONST char * PNG_CONST format_names[FORMAT_COUNT] =
+static const char * const format_names[FORMAT_COUNT] =
 {
    "sRGB-gray",
    "sRGB-gray+alpha",
@@ -579,11 +579,11 @@ typedef struct
    int         stride_extra;
    FILE       *input_file;
    png_voidp   input_memory;
-   png_size_t  input_memory_size;
+   size_t      input_memory_size;
    png_bytep   buffer;
    ptrdiff_t   stride;
-   png_size_t  bufsize;
+   size_t      bufsize;
-   png_size_t  allocsize;
+   size_t      allocsize;
    char        tmpfile_name[32];
    png_uint_16 colormap[256*4];
 }
@@ -666,7 +666,7 @@ static void initimage(Image *image, png_uint_32 opts, const char *file_name,
 static void
 allocbuffer(Image *image)
 {
-   png_size_t size = PNG_IMAGE_BUFFER_SIZE(image->image, image->stride);
+   size_t size = PNG_IMAGE_BUFFER_SIZE(image->image, image->stride);
 
    if (size+32 > image->bufsize)
    {
@@ -1143,7 +1143,7 @@ get_pixel(png_uint_32 format))(Pixel *p, png_const_voidp pb)
    }
 }
 
-/* Convertion between pixel formats.  The code above effectively eliminates the
+/* Conversion between pixel formats.  The code above effectively eliminates the
  * component ordering changes leaving three basic changes:
  *
  * 1) Remove an alpha channel by pre-multiplication or compositing on a
@@ -1151,7 +1151,7 @@ get_pixel(png_uint_32 format))(Pixel *p, png_const_voidp pb)
  *
  * 2) Remove color by mapping to grayscale.  (Grayscale to color is a no-op.)
  *
- * 3) Convert between 8-bit and 16-bit components.  (Both directtions are
+ * 3) Convert between 8-bit and 16-bit components.  (Both directions are
  *    relevant.)
  *
  * This gives the following base format conversion matrix:
@@ -2037,7 +2037,7 @@ typedef struct
    /* Precalculated values: */
    int          in_opaque;   /* Value of input alpha that is opaque */
    int          is_palette;  /* Sample values come from the palette */
-   int          accumulate;  /* Accumlate component errors (don't log) */
+   int          accumulate;  /* Accumulate component errors (don't log) */
    int          output_8bit; /* Output is 8-bit (else 16-bit) */
 
    void (*in_gp)(Pixel*, png_const_voidp);
@@ -2347,8 +2347,8 @@ static int
 logpixel(const Transform *transform, png_uint_32 x, png_uint_32 y,
    const Pixel *in, const Pixel *calc, const Pixel *out, const char *reason)
 {
-   const png_uint_32 in_format = transform->in_image->image.format;
+   png_uint_32 in_format = transform->in_image->image.format;
-   const png_uint_32 out_format = transform->out_image->image.format;
+   png_uint_32 out_format = transform->out_image->image.format;
 
    png_uint_32 back_format = out_format & ~PNG_FORMAT_FLAG_ALPHA;
    const char *via_linear = "";
@@ -2603,17 +2603,17 @@ compare_two_images(Image *a, Image *b, int via_linear,
    ptrdiff_t strideb = b->stride;
    png_const_bytep rowa = a->buffer+16;
    png_const_bytep rowb = b->buffer+16;
-   const png_uint_32 width = a->image.width;
+   png_uint_32 width = a->image.width;
-   const png_uint_32 height = a->image.height;
+   png_uint_32 height = a->image.height;
-   const png_uint_32 formata = a->image.format;
+   png_uint_32 formata = a->image.format;
-   const png_uint_32 formatb = b->image.format;
+   png_uint_32 formatb = b->image.format;
-   const unsigned int a_sample = PNG_IMAGE_SAMPLE_SIZE(formata);
+   unsigned int a_sample = PNG_IMAGE_SAMPLE_SIZE(formata);
-   const unsigned int b_sample = PNG_IMAGE_SAMPLE_SIZE(formatb);
+   unsigned int b_sample = PNG_IMAGE_SAMPLE_SIZE(formatb);
    int alpha_added, alpha_removed;
    int bchannels;
-   int btoa[4];
    png_uint_32 y;
    Transform tr;
+   int btoa[4]={0,0,0,0};
 
    /* This should never happen: */
    if (width != b->image.width || height != b->image.height)
@@ -2702,7 +2702,7 @@ compare_two_images(Image *a, Image *b, int via_linear,
             {
                if ((a->opts & ACCUMULATE) == 0)
                {
-                  char pindex[9];
+                  char pindex[16];
                   sprintf(pindex, "%lu[%lu]", (unsigned long)y,
                      (unsigned long)a->image.colormap_entries);
                   logerror(a, a->file_name, ": bad pixel index: ", pindex);
@@ -2714,7 +2714,7 @@ compare_two_images(Image *a, Image *b, int via_linear,
             {
                if ((b->opts & ACCUMULATE) == 0)
                {
-                  char pindex[9];
+                  char pindex[16];
                   sprintf(pindex, "%lu[%lu]", (unsigned long)y,
                      (unsigned long)b->image.colormap_entries);
                   logerror(b, b->file_name, ": bad pixel index: ", pindex);
@@ -2727,7 +2727,7 @@ compare_two_images(Image *a, Image *b, int via_linear,
                result = 0;
          }
 
-         /* If reqested copy the error values back from the Transform. */
+         /* If requested, copy the error values back from the Transform. */
          if (a->opts & ACCUMULATE)
          {
             tr.error_ptr[0] = tr.error[0];
@@ -2746,22 +2746,27 @@ compare_two_images(Image *a, Image *b, int via_linear,
        */
       else if ((a->opts & ACCUMULATE) == 0)
       {
+#        ifdef __GNUC__
+#           define BYTE_CHARS 20 /* 2^32: GCC sprintf warning */
+#        else
+#           define BYTE_CHARS 3 /* 2^8: real maximum value */
+#        endif
          /* Check the original image first,
           * TODO: deal with input images with bad pixel values?
           */
          if (amax >= a->image.colormap_entries)
          {
-            char pindex[9];
+            char pindex[3+2*BYTE_CHARS];
-            sprintf(pindex, "%d[%lu]", amax,
+            sprintf(pindex, "%d[%u]", amax,
-               (unsigned long)a->image.colormap_entries);
+               (png_byte)/*SAFE*/a->image.colormap_entries);
             return logerror(a, a->file_name, ": bad pixel index: ", pindex);
          }
 
          else if (bmax >= b->image.colormap_entries)
          {
-            char pindex[9];
+            char pindex[3+2*BYTE_CHARS];
-            sprintf(pindex, "%d[%lu]", bmax,
+            sprintf(pindex, "%d[%u]", bmax,
-               (unsigned long)b->image.colormap_entries);
+               (png_byte)/*SAFE*/b->image.colormap_entries);
             return logerror(b, b->file_name, ": bad pixel index: ", pindex);
          }
       }
@@ -2786,8 +2791,7 @@ compare_two_images(Image *a, Image *b, int via_linear,
       (formata & (formatb ^ PNG_FORMAT_FLAG_COLOR) & PNG_FORMAT_FLAG_COLOR)))
    {
       /* Was an alpha channel changed? */
-      const png_uint_32 alpha_changed = (formata ^ formatb) &
+      png_uint_32 alpha_changed = (formata ^ formatb) & PNG_FORMAT_FLAG_ALPHA;
-         PNG_FORMAT_FLAG_ALPHA;
 
       /* Was an alpha channel removed?  (The third test.)  If so the direct
        * comparison is only possible if the input alpha is opaque.
@@ -2817,8 +2821,11 @@ compare_two_images(Image *a, Image *b, int via_linear,
          bchannels = component_loc(bloc, formatb);
 
          /* Hence the btoa array. */
-         for (i=0; i<4; ++i) if (bloc[i] < 4)
+         for (i=0; i<4; ++i)
+         {
+            if (bloc[i] < 4)
                btoa[bloc[i]] = aloc[i]; /* may be '4' for alpha */
+         }
 
          if (alpha_added)
             alpha_added = bloc[0]; /* location of alpha channel in image b */
@@ -2881,10 +2888,13 @@ compare_two_images(Image *a, Image *b, int via_linear,
                {
                   case 4:
                      if (pua[btoa[3]] != pub[3]) break;
+                     /* FALLTHROUGH */
                   case 3:
                      if (pua[btoa[2]] != pub[2]) break;
+                     /* FALLTHROUGH */
                   case 2:
                      if (pua[btoa[1]] != pub[1]) break;
+                     /* FALLTHROUGH */
                   case 1:
                      if (pua[btoa[0]] != pub[0]) break;
                      if (alpha_added != 4 && pub[alpha_added] != 65535) break;
@@ -2900,10 +2910,13 @@ compare_two_images(Image *a, Image *b, int via_linear,
                {
                   case 4:
                      if (psa[btoa[3]] != psb[3]) break;
+                     /* FALLTHROUGH */
                   case 3:
                      if (psa[btoa[2]] != psb[2]) break;
+                     /* FALLTHROUGH */
                   case 2:
                      if (psa[btoa[1]] != psb[1]) break;
+                     /* FALLTHROUGH */
                   case 1:
                      if (psa[btoa[0]] != psb[0]) break;
                      if (alpha_added != 4 && psb[alpha_added] != 255) break;
@@ -2922,7 +2935,7 @@ compare_two_images(Image *a, Image *b, int via_linear,
       }
    }
 
-   /* If reqested copy the error values back from the Transform. */
+   /* If requested, copy the error values back from the Transform. */
    if (a->opts & ACCUMULATE)
    {
       tr.error_ptr[0] = tr.error[0];
@@ -3200,10 +3213,10 @@ write_one_file(Image *output, Image *image, int convert_to_8bit)
    else if (image->opts & USE_FILE)
    {
 #ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
-      static int counter = 0;
+      static unsigned int counter = 0;
       char name[32];
 
-      sprintf(name, "%s%d.png", tmpf, ++counter);
+      sprintf(name, "%s%u.png", tmpf, ++counter);
 
       if (png_image_write_to_file(&image->image, name, convert_to_8bit,
          image->buffer+16, (png_int_32)image->stride, image->colormap))
@@ -3617,7 +3630,7 @@ main(int argc, char **argv)
 
          if (arg[0] == '-')
          {
-            const int term = (arg[1] == '0' ? 0 : '\n');
+            int term = (arg[1] == '0' ? 0 : '\n');
             unsigned int ich = 0;
 
             /* Loop reading files, use a static buffer to simplify this and just

contrib/libtests/pngunknown.c

@@ -1,8 +1,8 @@
 
 /* pngunknown.c - test the read side unknown chunk handling
  *
- * Last changed in libpng 1.6.26 [October 20, 2016]
+ * Copyright (c) 2021 Cosmin Truta
- * Copyright (c) 2015,2016 Glenn Randers-Pehrson
+ * Copyright (c) 2015,2017 Glenn Randers-Pehrson
  * Written by John Cunningham Bowler
  *
  * This code is released under the libpng license.
@@ -56,7 +56,7 @@
    defined(PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED)
 
 #if PNG_LIBPNG_VER < 10500
-/* This deliberately lacks the PNG_CONST. */
+/* This deliberately lacks the const. */
 typedef png_byte *png_const_bytep;
 
 /* This is copied from 1.5.1 png.h: */
@@ -85,7 +85,7 @@ typedef png_byte *png_const_bytep;
 #define PNG_WRITE_16BIT_SUPPORTED
 #define PNG_READ_16BIT_SUPPORTED
 
-/* This comes from pnglibconf.h afer 1.5: */
+/* This comes from pnglibconf.h after 1.5: */
 #define PNG_FP_1 100000
 #define PNG_GAMMA_THRESHOLD_FIXED\
    ((png_fixed_point)(PNG_GAMMA_THRESHOLD * PNG_FP_1))
@@ -114,6 +114,7 @@ typedef png_byte *png_const_bytep;
 #define png_PLTE PNG_U32( 80,  76,  84,  69)
 #define png_bKGD PNG_U32( 98,  75,  71,  68)
 #define png_cHRM PNG_U32( 99,  72,  82,  77)
+#define png_eXIf PNG_U32(101,  88,  73, 102) /* registered July 2017 */
 #define png_fRAc PNG_U32(102,  82,  65,  99) /* registered, not defined */
 #define png_gAMA PNG_U32(103,  65,  77,  65)
 #define png_gIFg PNG_U32(103,  73,  70, 103)
@@ -210,6 +211,13 @@ static struct
          1,
 #     endif
       1,  START, 0 },
+   { "eXIf", PNG_INFO_eXIf, png_eXIf,
+#     ifdef PNG_READ_eXIf_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1,  END, 0 },
    { "gAMA", PNG_INFO_gAMA, png_gAMA,
 #     ifdef PNG_READ_gAMA_SUPPORTED
          0,
@@ -362,7 +370,9 @@ find_by_flag(png_uint_32 flag)
 {
    int i = NINFO;
 
-   while (--i >= 0) if (chunk_info[i].flag == flag) return i;
+   while (--i >= 0)
+      if (chunk_info[i].flag == flag)
+         return i;
 
    fprintf(stderr, "pngunknown: internal error\n");
    exit(4);
@@ -539,19 +549,21 @@ read_callback(png_structp pp, png_unknown_chunkp pc)
 
       case PNG_HANDLE_CHUNK_AS_DEFAULT:
       case PNG_HANDLE_CHUNK_NEVER:
-         discard = 1/*handled; discard*/;
+         discard = 1; /*handled; discard*/
          break;
 
       case PNG_HANDLE_CHUNK_IF_SAFE:
       case PNG_HANDLE_CHUNK_ALWAYS:
-         discard = 0/*not handled; keep*/;
+         discard = 0; /*not handled; keep*/
          break;
    }
 
    /* Also store information about this chunk in the display, the relevant flag
     * is set if the chunk is to be kept ('not handled'.)
     */
-   if (chunk >= 0) if (!discard) /* stupidity to stop a GCC warning */
+   if (chunk >= 0)
+   {
+      if (!discard) /* stupidity to stop a GCC warning */
       {
          png_uint_32 flag = chunk_info[chunk].flag;
 
@@ -561,6 +573,7 @@ read_callback(png_structp pp, png_unknown_chunkp pc)
          else
             d->before_IDAT |= flag;
       }
+   }
 
    /* However if there is no support to store unknown chunks don't ask libpng to
     * do it; there will be an png_error.
@@ -614,7 +627,7 @@ get_unknown(display *d, png_infop info_ptr, int after_IDAT)
                   ++(d->error_count);
                   break;
                }
-               /* FALL THROUGH (safe) */
+               /* FALLTHROUGH */ /* (safe) */
             case PNG_HANDLE_CHUNK_ALWAYS:
                break;
          }
@@ -833,7 +846,8 @@ check(FILE *fp, int argc, const char **argv, png_uint_32p flags/*out*/,
             {
                png_uint_32 y;
 
-               for (y=0; y<height; ++y) if (PNG_ROW_IN_INTERLACE_PASS(y, ipass))
+               for (y=0; y<height; ++y)
+                  if (PNG_ROW_IN_INTERLACE_PASS(y, ipass))
                      png_read_row(d->png_ptr, NULL, NULL);
             }
          }
@@ -1083,15 +1097,15 @@ perform_one_test_safe(FILE *fp, int argc, const char **argv,
 
 static const char *standard_tests[] =
 {
- "discard", "default=discard", 0,
+   "discard", "default=discard", NULL,
- "save", "default=save", 0,
+   "save", "default=save", NULL,
- "if-safe", "default=if-safe", 0,
+   "if-safe", "default=if-safe", NULL,
- "vpAg", "vpAg=if-safe", 0,
+   "vpAg", "vpAg=if-safe", NULL,
- "sTER", "sTER=if-safe", 0,
+   "sTER", "sTER=if-safe", NULL,
- "IDAT", "default=discard", "IDAT=save", 0,
+   "IDAT", "default=discard", "IDAT=save", NULL,
    "sAPI", "bKGD=save", "cHRM=save", "gAMA=save", "all=discard", "iCCP=save",
-   "sBIT=save", "sRGB=save", 0,
+      "sBIT=save", "sRGB=save", "eXIf=save", NULL,
- 0/*end*/
+   NULL /*end*/
 };
 
 static PNG_NORETURN void
@@ -1107,7 +1121,7 @@ int
 main(int argc, const char **argv)
 {
    FILE *fp;
-   png_uint_32 default_flags[4/*valid,unknown{before,after}*/];
+   png_uint_32 default_flags[4]; /*valid,unknown{before,after}*/
    int strict = 0, default_tests = 0;
    const char *count_argv = "default=save";
    const char *touch_file = NULL;
@@ -1145,7 +1159,8 @@ main(int argc, const char **argv)
    /* GCC BUG: if (default_tests && argc != 1) triggers some weird GCC argc
     * optimization which causes warnings with -Wstrict-overflow!
     */
-   else if (default_tests) if (argc != 1)
+   else if (default_tests)
+      if (argc != 1)
          usage(d.program, "extra arguments");
 
    /* The name of the test file is the last argument; remove it. */
@@ -1208,7 +1223,11 @@ main(int argc, const char **argv)
          const char *result;
          int arg_count = 0;
 
-         while (*next) ++next, ++arg_count;
+         while (*next != NULL)
+         {
+            ++next;
+            ++arg_count;
+         }
 
          perform_one_test_safe(fp, arg_count, test, default_flags, &d,
             this_test);

contrib/libtests/readpng.c

@@ -1,9 +1,8 @@
+
 /* readpng.c
  *
  * Copyright (c) 2013 John Cunningham Bowler
  *
- * Last changed in libpng 1.6.1 [March 28, 2013]
- *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
  * and license in png.h
@@ -60,7 +59,7 @@ read_png(FILE *fp)
    png_read_info(png_ptr, info_ptr);
 
    {
-      png_size_t rowbytes = png_get_rowbytes(png_ptr, info_ptr);
+      size_t rowbytes = png_get_rowbytes(png_ptr, info_ptr);
 
       /* Failure to initialize these is harmless */
       row = malloc(rowbytes);

contrib/libtests/tarith.c

@@ -1,10 +1,9 @@
 
 /* tarith.c
  *
+ * Copyright (c) 2021 Cosmin Truta
  * Copyright (c) 2011-2013 John Cunningham Bowler
  *
- * Last changed in libpng 1.6.0 [February 14, 2013]
- *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
  * and license in png.h
@@ -88,6 +87,7 @@ int validation_ascii_to_fp(int count, int argc, char **argv)
    int    minorarith = 0;
 
    while (--argc > 0)
+   {
       if (strcmp(*++argv, "-a") == 0)
          showall = 1;
       else if (strcmp(*argv, "-e") == 0 && argc > 0)
@@ -105,10 +105,11 @@ int validation_ascii_to_fp(int count, int argc, char **argv)
          fprintf(stderr, "unknown argument %s\n", *argv);
          return 1;
       }
+   }
 
    do
    {
-      png_size_t index;
+      size_t index;
       int state, failed = 0;
       char buffer[64];
 
@@ -130,8 +131,8 @@ int validation_ascii_to_fp(int count, int argc, char **argv)
        */
       if (buffer[precision+7] != 71)
       {
-         fprintf(stderr, "%g[%d] -> '%s'[%lu] buffer overflow\n", test,
+         fprintf(stderr, "%g[%d] -> '%s'[%lu] buffer overflow\n",
-            precision, buffer, (unsigned long)strlen(buffer));
+            test, precision, buffer, (unsigned long)strlen(buffer));
          failed = 1;
       }
 
@@ -146,16 +147,16 @@ int validation_ascii_to_fp(int count, int argc, char **argv)
          if (test >= 0 && strcmp(buffer, "inf") ||
              test <  0 && strcmp(buffer, "-inf"))
          {
-            fprintf(stderr, "%g[%d] -> '%s' but expected 'inf'\n", test,
+            fprintf(stderr, "%g[%d] -> '%s' but expected 'inf'\n",
-               precision, buffer);
+               test, precision, buffer);
             failed = 1;
          }
       }
       else if (!png_check_fp_number(buffer, precision+10, &state, &index) ||
           buffer[index] != 0)
       {
-         fprintf(stderr, "%g[%d] -> '%s' but has bad format ('%c')\n", test,
+         fprintf(stderr, "%g[%d] -> '%s' but has bad format ('%c')\n",
-         precision, buffer, buffer[index]);
+            test, precision, buffer, buffer[index]);
          failed = 1;
       }
       else if (PNG_FP_IS_NEGATIVE(state) && !(test < 0))
@@ -176,7 +177,7 @@ int validation_ascii_to_fp(int count, int argc, char **argv)
       }
       else if (PNG_FP_IS_POSITIVE(state) && !(test > 0))
       {
-         fprintf(stderr, "%g[%d] -> '%s' but postive value not so reported\n",
+         fprintf(stderr, "%g[%d] -> '%s' but positive value not so reported\n",
             test, precision, buffer);
          failed = 1;
          assert(!PNG_FP_IS_NEGATIVE(state));
@@ -187,7 +188,7 @@ int validation_ascii_to_fp(int count, int argc, char **argv)
          /* Check the result against the original. */
          double out = atof(buffer);
          double change = fabs((out - test)/test);
-         double allow = .5/pow(10,
+         double allow = .5 / pow(10,
             (precision >= DBL_DIG) ? DBL_DIG-1 : precision-1);
 
          /* NOTE: if you hit this error case are you compiling with gcc
@@ -257,8 +258,9 @@ skip:
    }
    while (--count);
 
-   printf("Tested %d finite values, %d non-finite, %d OK (%d failed) %d minor "
+   printf("Tested %d finite values, %d non-finite, %d OK (%d failed) "
-      "arithmetic errors\n", finite, nonfinite, ok, failcount, minorarith);
+      "%d minor arithmetic errors\n",
+      finite, nonfinite, ok, failcount, minorarith);
    printf(" Error with >=%d digit precision %.2f%%\n", DBL_DIG, max_abs);
    printf(" Error with < %d digit precision %.2f%%\n", DBL_DIG, max);
 
@@ -329,10 +331,10 @@ static int check_one_character(checkfp_command *co, checkfp_control c, int ch)
 {
    /* Test this character (ch) to ensure the parser does the correct thing.
     */
-   png_size_t index = 0;
+   size_t index = 0;
    const char test = (char)ch;
-   const int number_is_valid = png_check_fp_number(&test, 1, &c.state, &index);
+   int number_is_valid = png_check_fp_number(&test, 1, &c.state, &index);
-   const int character_accepted = (index == 1);
+   int character_accepted = (index == 1);
 
    if (c.check_state != exponent && isdigit(ch) && ch != '0')
       c.is_zero = 0;
@@ -371,8 +373,8 @@ static int check_one_character(checkfp_command *co, checkfp_control c, int ch)
    /* This should never fail (it's a serious bug if it does): */
    if (index != 0 && index != 1)
    {
-      fprintf(stderr, "%s: read beyond end of string (%lu)\n", co->number,
+      fprintf(stderr, "%s: read beyond end of string (%lu)\n",
-         (unsigned long)index);
+         co->number, (unsigned long)index);
       return 0;
    }
 
@@ -503,8 +505,8 @@ static int check_one_character(checkfp_command *co, checkfp_control c, int ch)
       if (number_is_valid != c.number_was_valid)
       {
          fprintf(stderr,
-            "%s: character '%c' [0x%.2x] changed number validity\n", co->number,
+            "%s: character '%c' [0x%.2x] changed number validity\n",
-            ch, ch);
+            co->number, ch, ch);
          return 0;
       }
 
@@ -521,11 +523,14 @@ static int check_all_characters(checkfp_command *co, checkfp_control c)
 {
    int ch;
 
-   if (c.cnumber+4 < sizeof co->number) for (ch=0; ch<256; ++ch)
+   if (c.cnumber+4 < sizeof co->number)
+   {
+      for (ch=0; ch<256; ++ch)
       {
          if (!check_one_character(co, c, ch))
             return 0;
       }
+   }
 
    return 1;
 }
@@ -539,11 +544,14 @@ static int check_some_characters(checkfp_command *co, checkfp_control c,
 
    if (c.cnumber+4 < sizeof co->number && c.limit >= 0)
    {
-      if (c.limit > 0) for (i=0; tests[i]; ++i)
+      if (c.limit > 0)
+      {
+         for (i=0; tests[i]; ++i)
          {
             if (!check_one_character(co, c, tests[i]))
                   return 0;
          }
+      }
 
       /* At the end check all the characters. */
       else
@@ -687,25 +695,25 @@ int validation_muldiv(int count, int argc, char **argv)
         ok = 0, ++overflow, fpround = fp/*misleading*/;
 
       if (verbose)
-         fprintf(stderr, "TEST %d * %d / %d -> %lld (%s)\n", a, times, div,
+         fprintf(stderr, "TEST %d * %d / %d -> %lld (%s)\n",
-            fp, ok ? "ok" : "overflow");
+            a, times, div, fp, ok ? "ok" : "overflow");
 
       ++tested;
       if (png_muldiv(&result, a, times, div) != ok)
       {
          ++error;
          if (ok)
-             fprintf(stderr, "%d * %d / %d -> overflow (expected %lld)\n", a,
+             fprintf(stderr, "%d * %d / %d -> overflow (expected %lld)\n",
-                times, div, fp);
+                a, times, div, fp);
          else
-             fprintf(stderr, "%d * %d / %d -> %d (expected overflow %lld)\n", a,
+             fprintf(stderr, "%d * %d / %d -> %d (expected overflow %lld)\n",
-                times, div, result, fp);
+                a, times, div, result, fp);
       }
       else if (ok && result != fpround)
       {
          ++error;
-         fprintf(stderr, "%d * %d / %d -> %d not %lld\n", a, times, div, result,
+         fprintf(stderr, "%d * %d / %d -> %d not %lld\n",
-            fp);
+            a, times, div, result, fp);
       }
       else
          ++passed;
@@ -721,8 +729,8 @@ int validation_muldiv(int count, int argc, char **argv)
    }
    while (--count > 0);
 
-   printf("%d tests including %d overflows, %d passed, %d failed (%d 64-bit "
+   printf("%d tests including %d overflows, %d passed, %d failed "
-      "errors)\n", tested, overflow, passed, error, error64);
+      "(%d 64-bit errors)\n", tested, overflow, passed, error, error64);
    return 0;
 }
 
@@ -821,8 +829,9 @@ int validation_gamma(int argc, char **argv)
          {
             if (error > .68) /* By experiment error is less than .68 */
             {
-               fprintf(stderr, "16-bit log error: %d: got %u, expected %f"
+               fprintf(stderr,
-                  " error: %f\n", i, png_log16bit(i), correct, error);
+                  "16-bit log error: %d: got %u, expected %f error: %f\n",
+                  i, png_log16bit(i), correct, error);
             }
          }
       }
@@ -841,8 +850,9 @@ int validation_gamma(int argc, char **argv)
             maxerr = fabs(error);
          if (fabs(error) > 1883) /* By experiment. */
          {
-            fprintf(stderr, "32-bit exp error: %d: got %u, expected %f"
+            fprintf(stderr,
-                  " error: %f\n", i, png_exp(i), correct, error);
+               "32-bit exp error: %d: got %u, expected %f error: %f\n",
+               i, png_exp(i), correct, error);
          }
       }
 
@@ -859,8 +869,9 @@ int validation_gamma(int argc, char **argv)
             maxerr = fabs(error);
          if (fabs(error) > .50002) /* By experiment */
          {
-            fprintf(stderr, "8-bit exp error: %d: got %u, expected %f"
+            fprintf(stderr,
-                  " error: %f\n", i, png_exp8bit(i), correct, error);
+               "8-bit exp error: %d: got %u, expected %f error: %f\n",
+               i, png_exp8bit(i), correct, error);
          }
       }
 
@@ -877,8 +888,9 @@ int validation_gamma(int argc, char **argv)
             maxerr = fabs(error);
          if (fabs(error) > .524) /* By experiment */
          {
-            fprintf(stderr, "16-bit exp error: %d: got %u, expected %f"
+            fprintf(stderr,
-                  " error: %f\n", i, png_exp16bit(i), correct, error);
+               "16-bit exp error: %d: got %u, expected %f error: %f\n",
+               i, png_exp16bit(i), correct, error);
          }
       }
 
@@ -940,7 +952,7 @@ int validation_gamma(int argc, char **argv)
 
 /**************************** VALIDATION TESTS ********************************/
 /* Various validation routines are included herein, they require some
- * definition for png_warning and png_error, seetings of VALIDATION:
+ * definition for png_warning and png_error, settings of VALIDATION:
  *
  * 1: validates the ASCII to floating point conversions
  * 2: validates png_muldiv

contrib/libtests/timepng.c

@@ -1,9 +1,8 @@
+
 /* timepng.c
  *
  * Copyright (c) 2013,2016 John Cunningham Bowler
  *
- * 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
@@ -65,7 +64,7 @@ typedef struct
 }  io_data;
 
 static PNG_CALLBACK(void, read_and_copy,
-      (png_structp png_ptr, png_bytep buffer, png_size_t cb))
+      (png_structp png_ptr, png_bytep buffer, size_t cb))
 {
    io_data *io = (io_data*)png_get_io_ptr(png_ptr);
 
@@ -100,7 +99,7 @@ static void read_by_row(png_structp png_ptr, png_infop info_ptr,
    png_read_info(png_ptr, info_ptr);
 
    {
-      png_size_t rowbytes = png_get_rowbytes(png_ptr, info_ptr);
+      size_t rowbytes = png_get_rowbytes(png_ptr, info_ptr);
 
       row = voidcast(png_bytep,malloc(rowbytes));
       display = voidcast(png_bytep,malloc(rowbytes));
@@ -528,7 +527,7 @@ int main(int argc, char **argv)
       }
    }
 
-   else if (nfiles == 0) /* Read from stdin withoout --dissemble */
+   else if (nfiles == 0) /* Read from stdin without --dissemble */
    {
       char filename[FILENAME_MAX+1];
 

contrib/mips-mmi/linux.c

@@ -0,0 +1,142 @@
+
+/* contrib/mips-mmi/linux.c
+ *
+ * Copyright (c) 2024 Cosmin Truta
+ * Written by guxiwei, 2023
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/auxv.h>
+
+/*
+ * parse_r var, r - Helper assembler macro for parsing register names.
+ *
+ * This converts the register name in $n form provided in \r to the
+ * corresponding register number, which is assigned to the variable \var. It is
+ * needed to allow explicit encoding of instructions in inline assembly where
+ * registers are chosen by the compiler in $n form, allowing us to avoid using
+ * fixed register numbers.
+ *
+ * It also allows newer instructions (not implemented by the assembler) to be
+ * transparently implemented using assembler macros, instead of needing separate
+ * cases depending on toolchain support.
+ *
+ * Simple usage example:
+ * __asm__ __volatile__("parse_r __rt, %0\n\t"
+ *                      ".insn\n\t"
+ *                      "# di    %0\n\t"
+ *                      ".word   (0x41606000 | (__rt << 16))"
+ *                      : "=r" (status);
+ */
+
+/* Match an individual register number and assign to \var */
+#define _IFC_REG(n)                                \
+        ".ifc        \\r, $" #n "\n\t"             \
+        "\\var        = " #n "\n\t"                \
+        ".endif\n\t"
+
+__asm__(".macro        parse_r var r\n\t"
+        "\\var        = -1\n\t"
+        _IFC_REG(0)  _IFC_REG(1)  _IFC_REG(2)  _IFC_REG(3)
+        _IFC_REG(4)  _IFC_REG(5)  _IFC_REG(6)  _IFC_REG(7)
+        _IFC_REG(8)  _IFC_REG(9)  _IFC_REG(10) _IFC_REG(11)
+        _IFC_REG(12) _IFC_REG(13) _IFC_REG(14) _IFC_REG(15)
+        _IFC_REG(16) _IFC_REG(17) _IFC_REG(18) _IFC_REG(19)
+        _IFC_REG(20) _IFC_REG(21) _IFC_REG(22) _IFC_REG(23)
+        _IFC_REG(24) _IFC_REG(25) _IFC_REG(26) _IFC_REG(27)
+        _IFC_REG(28) _IFC_REG(29) _IFC_REG(30) _IFC_REG(31)
+        ".iflt        \\var\n\t"
+        ".error        \"Unable to parse register name \\r\"\n\t"
+        ".endif\n\t"
+        ".endm");
+
+#define HWCAP_LOONGSON_CPUCFG (1 << 14)
+
+static int cpucfg_available(void)
+{
+    return getauxval(AT_HWCAP) & HWCAP_LOONGSON_CPUCFG;
+}
+
+static int strstart(const char *str, const char *pfx, const char **ptr)
+{
+    while (*pfx && *pfx == *str) {
+        pfx++;
+        str++;
+    }
+    if (!*pfx && ptr)
+        *ptr = str;
+    return !*pfx;
+}
+
+/* Most toolchains have no CPUCFG support yet */
+static uint32_t read_cpucfg(uint32_t reg)
+{
+        uint32_t __res;
+
+        __asm__ __volatile__(
+                "parse_r __res,%0\n\t"
+                "parse_r reg,%1\n\t"
+                ".insn \n\t"
+                ".word (0xc8080118 | (reg << 21) | (__res << 11))\n\t"
+                :"=r"(__res)
+                :"r"(reg)
+                :
+                );
+        return __res;
+}
+
+#define LOONGSON_CFG1 0x1
+
+#define LOONGSON_CFG1_MMI    (1 << 4)
+
+static int cpu_flags_cpucfg(void)
+{
+    int flags = 0;
+    uint32_t cfg1 = read_cpucfg(LOONGSON_CFG1);
+
+    if (cfg1 & LOONGSON_CFG1_MMI)
+        flags = 1;
+
+    return flags;
+}
+
+static int cpu_flags_cpuinfo(void)
+{
+    FILE *f = fopen("/proc/cpuinfo", "r");
+    char buf[200];
+    int flags = 0;
+
+    if (!f)
+        return flags;
+
+    while (fgets(buf, sizeof(buf), f)) {
+        /* Legacy kernel may not export MMI in ASEs implemented */
+        if (strstart(buf, "cpu model", NULL)) {
+            if (strstr(buf, "Loongson-3 "))
+                flags = 1;
+            break;
+        }
+        if (strstart(buf, "ASEs implemented", NULL)) {
+            if (strstr(buf, " loongson-mmi"))
+                flags = 1;
+            break;
+        }
+    }
+    fclose(f);
+    return flags;
+}
+
+static int png_have_mmi()
+{
+    if (cpucfg_available())
+        return cpu_flags_cpucfg();
+    else
+        return cpu_flags_cpuinfo();
+    return 0;
+}

contrib/mips-msa/linux.c

@@ -1,64 +1,55 @@
+
 /* contrib/mips-msa/linux.c
  *
+ * Copyright (c) 2020-2023 Cosmin Truta
  * Copyright (c) 2016 Glenn Randers-Pehrson
  * Written by Mandar Sahastrabuddhe, 2016.
- * Last changed in libpng 1.6.25beta03 [August 29, 2016]
+ * Updated by Sui Jingfeng, 2021.
  *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
  * and license in png.h
  *
- * SEE contrib/mips-msa/README before reporting bugs
+ * On Linux, png_have_msa is implemented by reading the pseudo-file
+ * "/proc/self/auxv".
+ *
+ * See contrib/mips-msa/README before reporting bugs.
  *
  * STATUS: SUPPORTED
  * BUG REPORTS: png-mng-implement@sourceforge.net
- *
- * png_have_msa 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 <elf.h>
-#include <string.h>
+#include <fcntl.h>
 #include <stdlib.h>
+#include <unistd.h>
 
 static int
 png_have_msa(png_structp png_ptr)
 {
-   FILE *f = fopen("/proc/cpuinfo", "rb");
+   Elf64_auxv_t aux;
+   int fd;
+   int has_msa = 0;
 
-   char *string = "msa";
+   fd = open("/proc/self/auxv", O_RDONLY);
-   char word[10];
+   if (fd >= 0)
+   {
+      while (read(fd, &aux, sizeof(Elf64_auxv_t)) == sizeof(Elf64_auxv_t))
+      {
+         if (aux.a_type == AT_HWCAP)
+         {
+            uint64_t hwcap = aux.a_un.a_val;
 
-   if (f != NULL)
+            has_msa = (hwcap >> 1) & 1;
-   {
+            break;
-      while(!feof(f))
-      {
-         int ch = fgetc(f);
-         static int i = 0;
-
-         while(!(ch <= 32))
-         {
-            word[i++] = ch;
-            ch = fgetc(f);
          }
-
-         int val = strcmp(string, word);
-
-         if (val == 0)
-            return 1;
-
-         i = 0;
-         memset(word, 0, 10);
       }
-
+      close(fd);
-      fclose(f);
    }
 #ifdef PNG_WARNINGS_SUPPORTED
    else
-      png_warning(png_ptr, "/proc/cpuinfo open failed");
+      png_warning(png_ptr, "/proc/self/auxv open failed");
 #endif
-   return 0;
+
+   return has_msa;
 }

contrib/oss-fuzz/Dockerfile

@@ -0,0 +1,25 @@
+# Copyright 2016 Google Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+################################################################################
+
+FROM gcr.io/oss-fuzz-base/base-builder
+MAINTAINER glennrp@gmail.com
+RUN apt-get update && \
+    apt-get install -y make autoconf automake libtool
+
+RUN git clone --depth 1 https://github.com/madler/zlib.git
+RUN git clone --depth 1 https://github.com/glennrp/libpng.git
+RUN cp libpng/contrib/oss-fuzz/build.sh $SRC
+WORKDIR libpng

contrib/oss-fuzz/README.txt

@@ -0,0 +1,36 @@
+Copyright (c) 2017 Glenn Randers-Pehrson
+
+This code is released under the libpng license.
+For conditions of distribution and use, see the disclaimer
+and license in png.h
+
+Files in this directory are used by the oss-fuzz project
+(https://github.com/google/oss-fuzz/tree/master/projects/libpng).
+for "fuzzing" libpng.
+
+They were licensed by Google Inc, using the BSD-like Chromium license,
+which may be found at https://cs.chromium.org/chromium/src/LICENSE, or, if
+noted in the source, under the Apache-2.0 license, which may
+be found at http://www.apache.org/licenses/LICENSE-2.0 .
+If they have been modified, the derivatives are copyright Glenn Randers-Pehrson
+and are released under the same licenses as the originals.  Several of
+the original files (libpng_read_fuzzer.options, png.dict, project.yaml)
+had no licensing information; we assumed that these were under the Chromium
+license. Any new files are released under the libpng license (see png.h).
+
+The files are
+                            Original
+ Filename                   or derived   Copyright          License
+ =========================  ==========   ================   ==========
+ Dockerfile*                derived      2017, Glenn R-P    Apache 2.0
+ build.sh                   derived      2017, Glenn R-P    Apache 2.0
+ libpng_read_fuzzer.cc      derived      2017, Glenn R-P    Chromium
+ libpng_read_fuzzer.options original     2015, Chrome Devs  Chromium
+ png.dict                   original     2015, Chrome Devs  Chromium
+ README.txt (this file)     original     2017, Glenn R-P    libpng
+
+ * Dockerfile is a copy of the file used by oss-fuzz. build.sh,
+   png.dict and libpng_read_fuzzer.* are the actual files used by oss-fuzz,
+   which retrieves them from the libpng repository at Github.
+
+To do: exercise the progressive reader and the png encoder.

contrib/oss-fuzz/build.sh

@@ -0,0 +1,50 @@
+#!/bin/bash -eu
+
+# Copyright 2017-2018 Glenn Randers-Pehrson
+# Copyright 2016 Google Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# Revisions by Glenn Randers-Pehrson, 2017:
+# 1. Build only the library, not the tools (changed "make -j$(nproc) all" to
+#     "make -j$(nproc) libpng16.la").
+# 2. Disabled WARNING and WRITE options in pnglibconf.dfa.
+# 3. Build zlib alongside libpng
+################################################################################
+
+# Disable logging via library build configuration control.
+cat scripts/pnglibconf.dfa | \
+  sed -e "s/option STDIO/option STDIO disabled/" \
+      -e "s/option WARNING /option WARNING disabled/" \
+      -e "s/option WRITE enables WRITE_INT_FUNCTIONS/option WRITE disabled/" \
+> scripts/pnglibconf.dfa.temp
+mv scripts/pnglibconf.dfa.temp scripts/pnglibconf.dfa
+
+# build the libpng library.
+autoreconf -f -i
+./configure --with-libpng-prefix=OSS_FUZZ_
+make -j$(nproc) clean
+make -j$(nproc) libpng16.la
+
+# build libpng_read_fuzzer.
+$CXX $CXXFLAGS -std=c++11 -I. \
+     $SRC/libpng/contrib/oss-fuzz/libpng_read_fuzzer.cc \
+     -o $OUT/libpng_read_fuzzer \
+     -lFuzzingEngine .libs/libpng16.a -lz
+
+# add seed corpus.
+find $SRC/libpng -name "*.png" | grep -v crashers | \
+     xargs zip $OUT/libpng_read_fuzzer_seed_corpus.zip
+
+cp $SRC/libpng/contrib/oss-fuzz/*.dict \
+     $SRC/libpng/contrib/oss-fuzz/*.options $OUT/

contrib/oss-fuzz/libpng_read_fuzzer.cc

@@ -0,0 +1,208 @@
+
+// libpng_read_fuzzer.cc
+// Copyright 2017-2018 Glenn Randers-Pehrson
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that may
+// be found in the LICENSE file https://cs.chromium.org/chromium/src/LICENSE
+
+// The modifications in 2017 by Glenn Randers-Pehrson include
+// 1. addition of a PNG_CLEANUP macro,
+// 2. setting the option to ignore ADLER32 checksums,
+// 3. adding "#include <string.h>" which is needed on some platforms
+//    to provide memcpy().
+// 4. adding read_end_info() and creating an end_info structure.
+// 5. adding calls to png_set_*() transforms commonly used by browsers.
+
+#include <stddef.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <vector>
+
+#define PNG_INTERNAL
+#include "png.h"
+
+#define PNG_CLEANUP \
+  if(png_handler.png_ptr) \
+  { \
+    if (png_handler.row_ptr) \
+      png_free(png_handler.png_ptr, png_handler.row_ptr); \
+    if (png_handler.end_info_ptr) \
+      png_destroy_read_struct(&png_handler.png_ptr, &png_handler.info_ptr,\
+        &png_handler.end_info_ptr); \
+    else if (png_handler.info_ptr) \
+      png_destroy_read_struct(&png_handler.png_ptr, &png_handler.info_ptr,\
+        nullptr); \
+    else \
+      png_destroy_read_struct(&png_handler.png_ptr, nullptr, nullptr); \
+    png_handler.png_ptr = nullptr; \
+    png_handler.row_ptr = nullptr; \
+    png_handler.info_ptr = nullptr; \
+    png_handler.end_info_ptr = nullptr; \
+  }
+
+struct BufState {
+  const uint8_t* data;
+  size_t bytes_left;
+};
+
+struct PngObjectHandler {
+  png_infop info_ptr = nullptr;
+  png_structp png_ptr = nullptr;
+  png_infop end_info_ptr = nullptr;
+  png_voidp row_ptr = nullptr;
+  BufState* buf_state = nullptr;
+
+  ~PngObjectHandler() {
+    if (row_ptr)
+      png_free(png_ptr, row_ptr);
+    if (end_info_ptr)
+      png_destroy_read_struct(&png_ptr, &info_ptr, &end_info_ptr);
+    else if (info_ptr)
+      png_destroy_read_struct(&png_ptr, &info_ptr, nullptr);
+    else
+      png_destroy_read_struct(&png_ptr, nullptr, nullptr);
+    delete buf_state;
+  }
+};
+
+void user_read_data(png_structp png_ptr, png_bytep data, size_t length) {
+  BufState* buf_state = static_cast<BufState*>(png_get_io_ptr(png_ptr));
+  if (length > buf_state->bytes_left) {
+    png_error(png_ptr, "read error");
+  }
+  memcpy(data, buf_state->data, length);
+  buf_state->bytes_left -= length;
+  buf_state->data += length;
+}
+
+void* limited_malloc(png_structp, png_alloc_size_t size) {
+  // libpng may allocate large amounts of memory that the fuzzer reports as
+  // an error. In order to silence these errors, make libpng fail when trying
+  // to allocate a large amount. This allocator used to be in the Chromium
+  // version of this fuzzer.
+  // This number is chosen to match the default png_user_chunk_malloc_max.
+  if (size > 8000000)
+    return nullptr;
+
+  return malloc(size);
+}
+
+void default_free(png_structp, png_voidp ptr) {
+  return free(ptr);
+}
+
+static const int kPngHeaderSize = 8;
+
+// Entry point for LibFuzzer.
+// Roughly follows the libpng book example:
+// http://www.libpng.org/pub/png/book/chapter13.html
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  if (size < kPngHeaderSize) {
+    return 0;
+  }
+
+  std::vector<unsigned char> v(data, data + size);
+  if (png_sig_cmp(v.data(), 0, kPngHeaderSize)) {
+    // not a PNG.
+    return 0;
+  }
+
+  PngObjectHandler png_handler;
+  png_handler.png_ptr = nullptr;
+  png_handler.row_ptr = nullptr;
+  png_handler.info_ptr = nullptr;
+  png_handler.end_info_ptr = nullptr;
+
+  png_handler.png_ptr = png_create_read_struct
+    (PNG_LIBPNG_VER_STRING, nullptr, nullptr, nullptr);
+  if (!png_handler.png_ptr) {
+    return 0;
+  }
+
+  png_handler.info_ptr = png_create_info_struct(png_handler.png_ptr);
+  if (!png_handler.info_ptr) {
+    PNG_CLEANUP
+    return 0;
+  }
+
+  png_handler.end_info_ptr = png_create_info_struct(png_handler.png_ptr);
+  if (!png_handler.end_info_ptr) {
+    PNG_CLEANUP
+    return 0;
+  }
+
+  // Use a custom allocator that fails for large allocations to avoid OOM.
+  png_set_mem_fn(png_handler.png_ptr, nullptr, limited_malloc, default_free);
+
+  png_set_crc_action(png_handler.png_ptr, PNG_CRC_QUIET_USE, PNG_CRC_QUIET_USE);
+#ifdef PNG_IGNORE_ADLER32
+  png_set_option(png_handler.png_ptr, PNG_IGNORE_ADLER32, PNG_OPTION_ON);
+#endif
+
+  // Setting up reading from buffer.
+  png_handler.buf_state = new BufState();
+  png_handler.buf_state->data = data + kPngHeaderSize;
+  png_handler.buf_state->bytes_left = size - kPngHeaderSize;
+  png_set_read_fn(png_handler.png_ptr, png_handler.buf_state, user_read_data);
+  png_set_sig_bytes(png_handler.png_ptr, kPngHeaderSize);
+
+  if (setjmp(png_jmpbuf(png_handler.png_ptr))) {
+    PNG_CLEANUP
+    return 0;
+  }
+
+  // Reading.
+  png_read_info(png_handler.png_ptr, png_handler.info_ptr);
+
+  // reset error handler to put png_deleter into scope.
+  if (setjmp(png_jmpbuf(png_handler.png_ptr))) {
+    PNG_CLEANUP
+    return 0;
+  }
+
+  png_uint_32 width, height;
+  int bit_depth, color_type, interlace_type, compression_type;
+  int filter_type;
+
+  if (!png_get_IHDR(png_handler.png_ptr, png_handler.info_ptr, &width,
+                    &height, &bit_depth, &color_type, &interlace_type,
+                    &compression_type, &filter_type)) {
+    PNG_CLEANUP
+    return 0;
+  }
+
+  // This is going to be too slow.
+  if (width && height > 100000000 / width) {
+    PNG_CLEANUP
+    return 0;
+  }
+
+  // Set several transforms that browsers typically use:
+  png_set_gray_to_rgb(png_handler.png_ptr);
+  png_set_expand(png_handler.png_ptr);
+  png_set_packing(png_handler.png_ptr);
+  png_set_scale_16(png_handler.png_ptr);
+  png_set_tRNS_to_alpha(png_handler.png_ptr);
+
+  int passes = png_set_interlace_handling(png_handler.png_ptr);
+
+  png_read_update_info(png_handler.png_ptr, png_handler.info_ptr);
+
+  png_handler.row_ptr = png_malloc(
+      png_handler.png_ptr, png_get_rowbytes(png_handler.png_ptr,
+                                            png_handler.info_ptr));
+
+  for (int pass = 0; pass < passes; ++pass) {
+    for (png_uint_32 y = 0; y < height; ++y) {
+      png_read_row(png_handler.png_ptr,
+                   static_cast<png_bytep>(png_handler.row_ptr), nullptr);
+    }
+  }
+
+  png_read_end(png_handler.png_ptr, png_handler.end_info_ptr);
+
+  PNG_CLEANUP
+  return 0;
+}

contrib/oss-fuzz/libpng_read_fuzzer.options

@@ -0,0 +1,2 @@
+[libfuzzer]
+dict = png.dict

contrib/oss-fuzz/png.dict

@@ -0,0 +1,39 @@
+#
+# AFL dictionary for PNG images
+# -----------------------------
+#
+# Just the basic, standard-originating sections; does not include vendor
+# extensions.
+#
+# Created by Michal Zalewski <lcamtuf@google.com>
+#
+
+header_png="\x89PNG\x0d\x0a\x1a\x0a"
+
+section_IDAT="IDAT"
+section_IEND="IEND"
+section_IHDR="IHDR"
+section_PLTE="PLTE"
+section_bKGD="bKGD"
+section_cHRM="cHRM"
+section_eXIf="eXIf"
+section_fRAc="fRAc"
+section_gAMA="gAMA"
+section_gIFg="gIFg"
+section_gIFt="gIFt"
+section_gIFx="gIFx"
+section_hIST="hIST"
+section_iCCP="iCCP"
+section_iTXt="iTXt"
+section_oFFs="oFFs"
+section_pCAL="pCAL"
+section_pHYs="pHYs"
+section_sBIT="sBIT"
+section_sCAL="sCAL"
+section_sPLT="sPLT"
+section_sRGB="sRGB"
+section_sTER="sTER"
+section_tEXt="tEXt"
+section_tIME="tIME"
+section_tRNS="tRNS"
+section_zTXt="zTXt"

contrib/pngminus/.gitignore

@@ -0,0 +1,11 @@
+# Compiled executables
+png2pnm
+png2pnm.exe
+png2pnm-static*
+pnm2png
+pnm2png.exe
+pnm2png-static*
+
+# Test artifacts
+*.png
+*.p[abgnp]m

contrib/pngminus/CHANGES.txt

@@ -0,0 +1,14 @@
+
+pnm2png / png2pnm --- conversion from PBM/PGM/PPM-file to PNG-file
+copyright (C) 1999-2019 by Willem van Schaik <willem at schaik dot com>
+
+version 1.0 - 1999.10.15 - First version.
+        1.1 - 2015.07.29 - Fix memory leaks (Glenn Randers-Pehrson)
+        1.2 - 2017.04.22 - Add buffer-size check
+        1.3 - 2017.08.24 - Fix potential overflow in buffer-size check
+                           (Glenn Randers-Pehrson)
+        1.4 - 2017.08.28 - Add PNGMINUS_UNUSED (Christian Hesse)
+        1.5 - 2018.08.05 - Fix buffer overflow in tokenizer (Cosmin Truta)
+        1.6 - 2018.08.05 - Improve portability and fix style (Cosmin Truta)
+        1.7 - 2019.01.22 - Change license to MIT (Willem van Schaik)
+        1.8 - 2024.01.09 - Fix, improve, modernize (Cosmin Truta)

contrib/pngminus/CMakeLists.txt

@@ -0,0 +1,41 @@
+# Copyright (c) 2018-2024 Cosmin Truta
+#
+# This software is released under the MIT license. For conditions of
+# distribution and use, see the LICENSE file part of this package.
+
+cmake_minimum_required(VERSION 3.5)
+
+project(PNGMINUS C)
+
+option(PNGMINUS_USE_SYSTEM_PNG
+       "Use the libpng build found in the system" OFF)
+
+add_executable(png2pnm png2pnm.c)
+add_executable(pnm2png pnm2png.c)
+
+if(PNGMINUS_USE_SYSTEM_PNG)
+    # Use the system libpng.
+    find_package(PNG REQUIRED)
+    target_link_libraries(png2pnm PRIVATE PNG::PNG)
+    target_link_libraries(pnm2png PRIVATE PNG::PNG)
+else()
+    # Build and use the internal libpng.
+    # Configure libpng for static linking, to produce single-file executables.
+    set(PNG_STATIC ON
+        CACHE STRING "Build the internal libpng as a static library" FORCE)
+    set(PNG_SHARED OFF
+        CACHE STRING "Build the internal libpng as a shared library" FORCE)
+    set(PNG_FRAMEWORK OFF
+        CACHE STRING "Build the internal libpng as a framework bundle" FORCE)
+    add_subdirectory(../.. libpng)
+    target_include_directories(png2pnm PRIVATE
+        "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/../..>"
+        "$<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}/libpng>"
+    )
+    target_include_directories(pnm2png PRIVATE
+        "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/../..>"
+        "$<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}/libpng>"
+    )
+    target_link_libraries(png2pnm PRIVATE png_static)
+    target_link_libraries(pnm2png PRIVATE png_static)
+endif()

contrib/pngminus/LICENSE.txt

@@ -0,0 +1,22 @@
+
+pnm2png / png2pnm --- conversion from PBM/PGM/PPM-file to PNG-file
+
+copyright (C) 1999-2019 by Willem van Schaik <willem at schaik dot com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+The software is provided "as is", without warranty of any kind, express or
+implied, including but not limited to the warranties of merchantability,
+fitness for a particular purpose and noninfringement. In no event shall the
+authors or copyright holders be liable for any claim, damages or other
+liability, whether in an action of contract, tort or otherwise, arising from,
+out of or in connection with the software or the use or other dealings in the
+software.

contrib/pngminus/Makefile

@@ -0,0 +1,62 @@
+# Makefile for PngMinus (png2pnm and pnm2png)
+# Linux / Unix
+
+#CC = cc
+CC = gcc
+LD = $(CC)
+
+RM = rm -f
+
+PNGINC = -I../..
+PNGLIB_SHARED = -L../.. -lpng
+PNGLIB_STATIC = ../../libpng.a
+
+# Uncomment the following if you have a custom zlib build at ../../../zlib
+#ZINC = -I../../../zlib
+#ZLIB_SHARED = -L../../../zlib -lz
+#ZLIB_STATIC = ../../../zlib/libz.a
+
+# Use the system zlib otherwise
+ZLIB_SHARED = -lz
+ZLIB_STATIC = -lz
+
+CPPFLAGS = $(PNGINC) $(ZINC)
+CFLAGS =
+LDFLAGS =
+LIBS_SHARED = $(PNGLIB_SHARED) $(ZLIB_SHARED)
+LIBS_STATIC = $(PNGLIB_STATIC) $(ZLIB_STATIC)
+
+EXEEXT =
+#EXEEXT = .exe
+
+# dependencies
+
+all: png2pnm$(EXEEXT) pnm2png$(EXEEXT) png2pnm-static$(EXEEXT) pnm2png-static$(EXEEXT)
+
+png2pnm.o: png2pnm.c
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) png2pnm.c
+
+pnm2png.o: pnm2png.c
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) pnm2png.c
+
+png2pnm$(EXEEXT): png2pnm.o
+	$(LD) $(LDFLAGS) -o png2pnm$(EXEEXT) png2pnm.o $(LIBS_SHARED) -lm
+
+pnm2png$(EXEEXT): pnm2png.o
+	$(LD) $(LDFLAGS) -o pnm2png$(EXEEXT) pnm2png.o $(LIBS_SHARED) -lm
+
+png2pnm-static$(EXEEXT): png2pnm.o
+	$(LD) $(LDFLAGS) -o png2pnm-static$(EXEEXT) png2pnm.o $(LIBS_STATIC) -lm
+
+pnm2png-static$(EXEEXT): pnm2png.o
+	$(LD) $(LDFLAGS) -o pnm2png-static$(EXEEXT) pnm2png.o $(LIBS_STATIC) -lm
+
+clean:
+	$(RM) png2pnm.o
+	$(RM) pnm2png.o
+	$(RM) png2pnm$(EXEEXT)
+	$(RM) pnm2png$(EXEEXT)
+	$(RM) png2pnm-static$(EXEEXT)
+	$(RM) pnm2png-static$(EXEEXT)
+
+# End of makefile for png2pnm / pnm2png

contrib/pngminus/README.txt

@@ -1,26 +1,16 @@
 PngMinus
 --------
-(copyright Willem van Schaik, 1999)
+(copyright Willem van Schaik, 1999-2019)
 
 
-License
--------
-
-Permission to use, copy, modify, and distribute this software and
-its documentation for any purpose and without fee is hereby granted,
-provided that the above copyright notice appear in all copies and
-that both that copyright notice and this permission notice appear in
-supporting documentation. This software is provided "as is" without
-express or implied warranty.
-
 
 Some history
 ------------
 Soon after the creation of PNG in 1995, the need was felt for a set of
-pnmtopng / pngtopnm utilities. Independantly Alexander Lehmann and I
+pnmtopng / pngtopnm utilities. Independently Alexander Lehmann and I
 (Willem van Schaik) started such a project. Luckily we discovered this
-and merged the two together into pnmtopng.tar.gz, which is available
+and merged the two, which later became part of NetPBM, available from
-from a/o ftp://ftp.simplesystems.org/pub/libpng/png/.
+SourceForge.
 
 These two utilities have many, many options and make use of most of the
 features of PNG, like gamma, alpha, sbit, text-chunks, etc. This makes
@@ -35,8 +25,8 @@ makes the whole setup a bit bulky. But that's unavoidable given the many
 features of pnmtopng.
 
 
-What now
+What now (1999)
---------
+---------------
 At this moment libpng is in a very stable state and can do much of the
 work done in pnmtopng. Also, pnmtopng needs to be upgraded to the new
 interface of libpng. Hence, it is time for a rewrite from the ground up
@@ -49,8 +39,8 @@ a small prototype that contains only the basic functionality. It doesn't
 have any of the options to read or write special chunks and it will do
 no gamma correction. But this makes it also a simple program that is
 quite easy to understand and can serve well as a template for other
-software developments. (By now there are of course a couple of programs,
+software developments. By now there are of course a couple of programs,
-like Greg Roelofs' rpng/wpng, that can be used just as good.)
+like Greg Roelofs' rpng/wpng, that can be used just as good.
 
 
 Can and can not
@@ -60,7 +50,8 @@ PngMinus. Because I started this development in good-old Turbo-C, I
 avoided the use the netpbm library, which requires DOS extenders. Again,
 another reason to call it PngMinus (minus netpbm :-). So, part of the
 program are some elementary routines to read / write pgm- and ppm-files.
-It does not read b&w pbm-files.
+It does not handle B&W pbm-files, but instead you could do pgm with bit-
+depth 1.
 
 The downside of this approach is that you can not use them on images
 that require blocks of memory bigger than 64k (the DOS version). For
@@ -96,58 +87,34 @@ To list the options type "png2pnm -h" or "pnm2png -h".
 
 Just like Scandinavian furniture
 --------------------------------
-You have to put it together yourself. I did test the software under
+You have to put it together yourself. I developed the software on MS-DOS
-MS-DOS with Turbo-C 3.0 and under RedHat Linux 4.2 with gcc. In both
+with Turbo-C 3.0 and RedHat Linux 4.2 with gcc. In both cases I used
-cases I used libpng-1.0.4 and zlib-1.1.3. Later versions should be OK,
+libpng-1.0.4 and zlib-1.1.3. By now (2019) it is twenty years later and
-however some older libpng versions have a bug in pngmem.c when using
+more current versions are OK.
-Turbo-C 3.0 (see below).
 
-You can build it using one of the two makefiles (make -f makefile.###)
+The makefile assumes that the libpng libraries can be found in ../.. and
-or use the batch/script files pngminus.bat / pngminus.sh. This assumes
+libz in ../../../zlib. But you can change this to for example ../libpng
-that you have built the libraries in ../libpng and ../zlib. Using Linux,
+and ../zlib. The makefile creates two versions of each program, one with
-make sure that you have built libpng with makefile.std and not
+static library support and the other using shared libraries.
-makefile.linux (also called .lnx in earlier versions of libpng). The
-latter creates a .so shared-library, while the PngMinus makefile assumes
-a normal .a static library.
 
 If you create a ../pngsuite directory and then store the basn####.png
 files from PngSuite (http://www.schaik.com/pngsuite/) in there, you can
-test in one go the proper functioning of PngMinus, see png2pnm.bat and
+test the proper functioning of PngMinus by running pngminus.sh.
-pnm2png.bat (or the .sh versions).
 
 
 Warranty
 -------
 Please, remember that this was just a small experiment to learn a few
-things. It will have many unforeseen features <vbg>. Who said bugs? Use
+things. It will have many unforeseen features <vbg> ... who said bugs? Use
-it when you are in need for something simple or when you want to start
+it when you are in need for something simple or when you want a starting
-developing your own stuff.
+point for developing your own stuff.
-
-
-The Turbo bug
--------------
-** pngmem.old
-          hptr = (png_byte huge *)((long)(hptr) & 0xfffffff0L);
-          hptr += 16L;
-** pngmem.c
-          hptr = (png_byte huge *)((long)(hptr) & 0xfffffff0L);
-          hptr = hptr + 16L;
-**
-
-** pngmem.old
-          png_ptr->offset_table_ptr[i] = (png_bytep)hptr;
-          hptr += (png_uint_32)65536L;
-** pngmem.c
-          png_ptr->offset_table_ptr[i] = (png_bytep)hptr;
-          hptr = hptr + 65536L;
-**
 
 
 The end
 -------
 Willem van Schaik
-mailto:willem at schaik.com
+mailto:willem at schaik dot com
 http://www.schaik.com/png/
--------
+
-Oct 1999
+Oct 1999, Jan 2019
 

contrib/pngminus/makefile.std

@@ -1,66 +0,0 @@
-# Makefile for PngMinus (png2pnm and pnm2png)
-# Linux / Unix
-
-#CC=cc
-CC=gcc
-LD=$(CC)
-
-RM=rm -f
-
-#PNGPATH = /usr/local
-#PNGINC = -I$(PNGPATH)/include/libpng16
-#PNGLIB = -L$(PNGPATH)/lib -lpng16
-#PNGLIBS = $(PNGPATH)/lib/libpng16.a
-PNGINC = -I../..
-PNGLIB = -L../.. -lpng
-PNGLIBS = ../../libpng.a
-
-#ZPATH = /usr/local
-#ZINC = -I$(ZPATH)/include
-#ZLIB = -L$(ZPATH)/lib -lz
-#ZLIBS = $(ZPATH)/lib/libz.a
-ZINC = -I../../../zlib
-ZLIB = -L../../../zlib -lz
-ZLIBS = ../../../zlib/libz.a
-
-CPPFLAGS=$(PNGINC) $(ZINC)
-CFLAGS=
-LDLIBS=$(PNGLIB) $(ZLIB)
-LDLIBSS=$(PNGLIBS) $(ZLIBS)
-C=.c
-O=.o
-L=.a
-E=
-
-# dependencies
-
-#all: png2pnm$(E) pnm2png$(E)
-all: png2pnm$(E) pnm2png$(E) png2pnm-static$(E) pnm2png-static$(E)
-
-png2pnm$(O): png2pnm$(C)
-	$(CC) -c $(CPPFLAGS) $(CFLAGS) png2pnm$(C)
-
-png2pnm$(E): png2pnm$(O)
-	$(LD) $(LDFLAGS) -o png2pnm$(E) png2pnm$(O) $(LDLIBS) -lm
-
-png2pnm-static$(E): png2pnm$(O)
-	$(LD) $(LDFLAGS) -o png2pnm-static$(E) png2pnm$(O) $(LDLIBSS) -lm
-
-pnm2png$(O): pnm2png$(C)
-	$(CC) -c $(CPPFLAGS) $(CFLAGS) pnm2png$(C)
-
-pnm2png$(E): pnm2png$(O)
-	$(LD) $(LDFLAGS) -o pnm2png$(E) pnm2png$(O) $(LDLIBS) -lm
-
-pnm2png-static$(E): pnm2png$(O)
-	$(LD) $(LDFLAGS) -o pnm2png-static$(E) pnm2png$(O) $(LDLIBSS) -lm
-
-clean:
-	$(RM) png2pnm$(O)
-	$(RM) pnm2png$(O)
-	$(RM) png2pnm$(E)
-	$(RM) pnm2png$(E)
-	$(RM) png2pnm-static$(E)
-	$(RM) pnm2png-static$(E)
-
-# End of makefile for png2pnm / pnm2png

contrib/pngminus/makefile.tc3

@@ -1,38 +0,0 @@
-# Makefile for PngMinus (png2pnm and pnm2png)
-# TurboC++ 3.0
-
-CC=tcc -Ic:\tc3\inc
-LD=tcc -Lc:\tc3\lib
-LB=tlib
-RM=del
-CP=copy
-MODEL=l
-CPPFLAGS=-I..\libpng -I..\zlib
-CFLAGS=-O -m$(MODEL)
-LDFLAGS=-m$(MODEL) -L..\libpng -L..\zlib
-C=.c
-O=.obj
-L=.lib
-E=.exe
-
-# dependencies
-
-all: png2pnm$(E) pnm2png$(E)
-
-png2pnm$(O): png2pnm$(C)
-        $(CC) -c $(CPPFLAGS) $(CFLAGS) png2pnm$(C)
-
-png2pnm$(E): png2pnm$(O)
-        $(LD) $(LDFLAGS) png2pnm$(O) libpng$(L) zlib$(L)
-
-pnm2png$(O): pnm2png$(C)
-        $(CC) -c $(CPPFLAGS) $(CFLAGS) pnm2png$(C)
-
-pnm2png$(E): pnm2png$(O)
-        $(LD) $(LDFLAGS) pnm2png$(O) libpng$(L) zlib$(L)
-
-clean:
-        $(RM) *$(O)
-        $(RM) *$(E)
-
-# End of makefile for png2pnm / pnm2png

contrib/pngminus/png2pnm.c

@@ -1,72 +1,52 @@
 /*
  *  png2pnm.c --- conversion from PNG-file to PGM/PPM-file
- *  copyright (C) 1999 by Willem van Schaik <willem at schaik.com>
+ *  copyright (C) 1999-2019 by Willem van Schaik <willem at schaik dot com>
  *
- *  version 1.0 - 1999.10.15 - First version.
+ *  This software is released under the MIT license. For conditions of
- *
+ *  distribution and use, see the LICENSE file part of this package.
- *  Permission to use, copy, modify, and distribute this software and
- *  its documentation for any purpose and without fee is hereby granted,
- *  provided that the above copyright notice appear in all copies and
- *  that both that copyright notice and this permission notice appear in
- *  supporting documentation. This software is provided "as is" without
- *  express or implied warranty.
  */
 
 #include <stdio.h>
 #include <stdlib.h>
-#ifdef __TURBOC__
-#include <mem.h>
 #include <fcntl.h>
-#endif
-#include <zlib.h>
 
 #ifndef BOOL
 #define BOOL unsigned char
 #endif
 #ifndef TRUE
-#define TRUE (BOOL) 1
+#define TRUE ((BOOL) 1)
 #endif
 #ifndef FALSE
-#define FALSE (BOOL) 0
+#define FALSE ((BOOL) 0)
-#endif
-
-#ifdef __TURBOC__
-#define STDIN  0
-#define STDOUT 1
-#define STDERR 2
-#endif
-
-/* to make png2pnm verbose so we can find problems (needs to be before png.h) */
-#ifndef PNG_DEBUG
-#define PNG_DEBUG 0
 #endif
 
 #include "png.h"
 
-/* Define png_jmpbuf() in case we are using a pre-1.0.6 version of libpng */
-#ifndef png_jmpbuf
-#  define png_jmpbuf(png_ptr) ((png_ptr)->jmpbuf)
-#endif
-
 /* function prototypes */
 
 int main (int argc, char *argv[]);
 void usage ();
-BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw,
+BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file,
-   BOOL alpha);
+              BOOL raw, BOOL alpha);
+BOOL do_png2pnm (png_struct *png_ptr, png_info *info_ptr,
+                 FILE *pnm_file, FILE *alpha_file,
+                 BOOL raw, BOOL alpha);
 
 /*
  *  main
  */
 
-int main(int argc, char *argv[])
+int main (int argc, char *argv[])
 {
   FILE *fp_rd = stdin;
   FILE *fp_wr = stdout;
   FILE *fp_al = NULL;
+  const char *fname_wr = NULL;
+  const char *fname_al = NULL;
   BOOL raw = TRUE;
   BOOL alpha = FALSE;
   int argi;
+  int ret;
 
   for (argi = 1; argi < argc; argi++)
   {
@@ -85,22 +65,23 @@ int main(int argc, char *argv[])
           argi++;
           if ((fp_al = fopen (argv[argi], "wb")) == NULL)
           {
+            fname_al = argv[argi];
             fprintf (stderr, "PNM2PNG\n");
-            fprintf (stderr, "Error:  can not create alpha-channel file %s\n",
+            fprintf (stderr, "Error:  cannot create alpha-channel file %s\n",
                      argv[argi]);
             exit (1);
           }
           break;
         case 'h':
         case '?':
-          usage();
+          usage ();
-          exit(0);
+          exit (0);
           break;
         default:
           fprintf (stderr, "PNG2PNM\n");
           fprintf (stderr, "Error:  unknown option %s\n", argv[argi]);
-          usage();
+          usage ();
-          exit(1);
+          exit (1);
           break;
       } /* end switch */
     }
@@ -115,10 +96,11 @@ int main(int argc, char *argv[])
     }
     else if (fp_wr == stdout)
     {
+      fname_wr = argv[argi];
       if ((fp_wr = fopen (argv[argi], "wb")) == NULL)
       {
         fprintf (stderr, "PNG2PNM\n");
-        fprintf (stderr, "Error:  can not create file %s\n", argv[argi]);
+        fprintf (stderr, "Error:  cannot create file %s\n", argv[argi]);
         exit (1);
       }
     }
@@ -126,30 +108,21 @@ int main(int argc, char *argv[])
     {
       fprintf (stderr, "PNG2PNM\n");
       fprintf (stderr, "Error:  too many parameters\n");
-      usage();
+      usage ();
-      exit(1);
+      exit (1);
     }
   } /* end for */
 
-#ifdef __TURBOC__
+#if defined(O_BINARY) && (O_BINARY != 0)
   /* set stdin/stdout if required to binary */
   if (fp_rd == stdin)
-  {
+    setmode (fileno (stdin), O_BINARY);
-    setmode (STDIN, O_BINARY);
-  }
   if ((raw) && (fp_wr == stdout))
-  {
+    setmode (fileno (stdout), O_BINARY);
-    setmode (STDOUT, O_BINARY);
-  }
 #endif
 
   /* call the conversion program itself */
-  if (png2pnm (fp_rd, fp_wr, fp_al, raw, alpha) == FALSE)
+  ret = png2pnm (fp_rd, fp_wr, fp_al, raw, alpha);
-  {
-    fprintf (stderr, "PNG2PNM\n");
-    fprintf (stderr, "Error:  unsuccessful conversion of PNG-image\n");
-    exit(1);
-  }
 
   /* close input file */
   fclose (fp_rd);
@@ -159,6 +132,17 @@ int main(int argc, char *argv[])
   if (alpha)
     fclose (fp_al);
 
+  if (!ret)
+  {
+    fprintf (stderr, "PNG2PNM\n");
+    fprintf (stderr, "Error:  unsuccessful conversion of PNG-image\n");
+    if (fname_wr)
+      remove (fname_wr); /* no broken output file shall remain behind */
+    if (fname_al)
+      remove (fname_al); /* ditto */
+    exit (1);
+  }
+
   return 0;
 }
 
@@ -166,15 +150,10 @@ int main(int argc, char *argv[])
  *  usage
  */
 
-void usage()
+void usage ()
 {
   fprintf (stderr, "PNG2PNM\n");
   fprintf (stderr, "   by Willem van Schaik, 1999\n");
-#ifdef __TURBOC__
-  fprintf (stderr, "   for Turbo-C and Borland-C compilers\n");
-#else
-  fprintf (stderr, "   for Linux (and Unix) compilers\n");
-#endif
   fprintf (stderr, "Usage:  png2pnm [options] <file>.png [<file>.pnm]\n");
   fprintf (stderr, "   or:  ... | png2pnm [options]\n");
   fprintf (stderr, "Options:\n");
@@ -191,37 +170,13 @@ void usage()
  */
 
 BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file,
-    volatile BOOL raw, BOOL alpha)
+              BOOL raw, BOOL alpha)
 {
-  png_struct    *png_ptr = NULL;
+  png_struct    *png_ptr;
-  png_info        *info_ptr = NULL;
+  png_info      *info_ptr;
-  png_byte      buf[8];
+  BOOL          ret;
-  png_byte      *png_pixels = NULL;
-  png_byte      **row_pointers = NULL;
-  png_byte      *pix_ptr = NULL;
-  png_uint_32   row_bytes;
 
-  png_uint_32   width;
+  /* initialize the libpng context for reading from png_file */
-  png_uint_32   height;
-  int           bit_depth;
-  int           channels;
-  int           color_type;
-  int           alpha_present;
-  int           row, col;
-  int           ret;
-  int           i;
-  long          dep_16;
-
-  /* read and check signature in PNG file */
-  ret = fread (buf, 1, 8, png_file);
-  if (ret != 8)
-    return FALSE;
-
-  ret = png_sig_cmp (buf, 0, 8);
-  if (ret)
-    return FALSE;
-
-  /* create png and info structures */
 
   png_ptr = png_create_read_struct (png_get_libpng_ver(NULL),
                                     NULL, NULL, NULL);
@@ -235,36 +190,51 @@ BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file,
     return FALSE; /* out of memory */
   }
 
-  if (setjmp (png_jmpbuf(png_ptr)))
+  if (setjmp (png_jmpbuf (png_ptr)))
   {
     png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
-    return FALSE;
+    return FALSE; /* generic libpng error */
   }
 
-  /* set up the input control for C streams */
   png_init_io (png_ptr, png_file);
-  png_set_sig_bytes (png_ptr, 8);  /* we already read the 8 signature bytes */
 
-  /* read the file information */
+  /* do the actual conversion */
-  png_read_info (png_ptr, info_ptr);
+  ret = do_png2pnm (png_ptr, info_ptr, pnm_file, alpha_file, raw, alpha);
 
-  /* get size and bit-depth of the PNG-image */
+  /* clean up the libpng structures and their internally-managed data */
-  png_get_IHDR (png_ptr, info_ptr,
+  png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
-    &width, &height, &bit_depth, &color_type,
-    NULL, NULL, NULL);
 
-  /* set-up the transformations */
+  return ret;
+}
 
-  /* transform paletted images into full-color rgb */
+/*
-  if (color_type == PNG_COLOR_TYPE_PALETTE)
+ *  do_png2pnm - does the conversion in a fully-initialized libpng context
-    png_set_expand (png_ptr);
+ */
-  /* expand images to bit-depth 8 (only applicable for grayscale images) */
+
-  if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
+BOOL do_png2pnm (png_struct *png_ptr, png_info *info_ptr,
-    png_set_expand (png_ptr);
+                 FILE *pnm_file, FILE *alpha_file,
-  /* transform transparency maps into full alpha-channel */
+                 BOOL raw, BOOL alpha)
-  if (png_get_valid (png_ptr, info_ptr, PNG_INFO_tRNS))
+{
+  png_byte      **row_pointers;
+  png_byte      *pix_ptr;
+  png_uint_32   width;
+  png_uint_32   height;
+  int           bit_depth;
+  int           channels;
+  int           color_type;
+  int           alpha_present;
+  png_uint_32   row, col, i;
+  long          dep_16;
+
+  /* set up the image transformations that are necessary for the PNM format */
+
+  /* set up (if applicable) the expansion of paletted images to full-color rgb,
+   * and the expansion of transparency maps to full alpha-channel */
   png_set_expand (png_ptr);
 
+  /* set up (if applicable) the expansion of grayscale images to bit-depth 8 */
+  png_set_expand_gray_1_2_4_to_8 (png_ptr);
+
 #ifdef NJET
   /* downgrade 16-bit images to 8-bit */
   if (bit_depth == 16)
@@ -273,30 +243,22 @@ BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file,
   if (color_type == PNG_COLOR_TYPE_GRAY ||
       color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
     png_set_gray_to_rgb (png_ptr);
-  /* only if file has a file gamma, we do a correction */
+  /* if the PNG image has a gAMA chunk then gamma-correct the output image */
+  {
+    double file_gamma;
     if (png_get_gAMA (png_ptr, info_ptr, &file_gamma))
       png_set_gamma (png_ptr, (double) 2.2, file_gamma);
+  }
 #endif
 
-  /* all transformations have been registered; now update info_ptr data,
+  /* read the image file, with all of the above image transforms applied */
-   * get rowbytes and channels, and allocate image memory */
+  png_read_png (png_ptr, info_ptr, 0, NULL);
 
-  png_read_update_info (png_ptr, info_ptr);
+  /* get the image size, bit-depth and color-type */
-
-  /* get the new color-type and bit-depth (after expansion/stripping) */
   png_get_IHDR (png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
                 NULL, NULL, NULL);
 
-  /* check for 16-bit files */
+  /* calculate the number of channels and store alpha-presence */
-  if (bit_depth == 16)
-  {
-    raw = FALSE;
-#ifdef __TURBOC__
-    pnm_file->flags &= ~((unsigned) _F_BIN);
-#endif
-  }
-
-  /* calculate new number of channels and store alpha-presence */
   if (color_type == PNG_COLOR_TYPE_GRAY)
     channels = 1;
   else if (color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
@@ -313,40 +275,12 @@ BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file,
   if (alpha && !alpha_present)
   {
     fprintf (stderr, "PNG2PNM\n");
-    fprintf (stderr, "Error:  PNG-file doesn't contain alpha channel\n");
+    fprintf (stderr, "Warning:  no alpha channel in PNG file\n");
-    exit (1);
-  }
-
-  /* row_bytes is the width x number of channels x (bit-depth / 8) */
-  row_bytes = png_get_rowbytes (png_ptr, info_ptr);
-
-  if ((png_pixels = (png_byte *)
-     malloc (row_bytes * height * sizeof (png_byte))) == NULL) {
-    png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
     return FALSE;
   }
 
-  if ((row_pointers = (png_byte **)
+  /* get address of internally-allocated image data */
-     malloc (height * sizeof (png_bytep))) == NULL)
+  row_pointers = png_get_rows (png_ptr, info_ptr);
-  {
-    png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
-    free (png_pixels);
-    png_pixels = NULL;
-    return FALSE;
-  }
-
-  /* set the individual row_pointers to point at the correct offsets */
-  for (i = 0; i < ((int) height); i++)
-    row_pointers[i] = png_pixels + i * row_bytes;
-
-  /* now we can go ahead and just read the whole image */
-  png_read_image (png_ptr, row_pointers);
-
-  /* read rest of file, and get additional chunks in info_ptr - REQUIRED */
-  png_read_end (png_ptr, info_ptr);
-
-  /* clean up after the read, and free any memory allocated - REQUIRED */
-  png_destroy_read_struct (&png_ptr, &info_ptr, (png_infopp) NULL);
 
   /* write header of PNM file */
 
@@ -377,45 +311,67 @@ BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file,
   }
 
   /* write data to PNM file */
-  pix_ptr = png_pixels;
 
-  for (row = 0; row < (int) height; row++)
+  for (row = 0; row < height; row++)
   {
-    for (col = 0; col < (int) width; col++)
+    pix_ptr = row_pointers[row];
+    for (col = 0; col < width; col++)
     {
-      for (i = 0; i < (channels - alpha_present); i++)
+      for (i = 0; i < (png_uint_32) (channels - alpha_present); i++)
       {
         if (raw)
-          fputc ((int) *pix_ptr++ , pnm_file);
+        {
-        else
+          fputc ((int) *pix_ptr++, pnm_file);
-          if (bit_depth == 16){
+          if (bit_depth == 16)
-            dep_16 = (long) *pix_ptr++;
+            fputc ((int) *pix_ptr++, pnm_file);
-            fprintf (pnm_file, "%ld ", (dep_16 << 8) + ((long) *pix_ptr++));
         }
         else
+        {
+          if (bit_depth == 16)
+          {
+            dep_16 = ((long) *pix_ptr++) << 8;
+            dep_16 += ((long) *pix_ptr++);
+            fprintf (pnm_file, "%ld ", dep_16);
+          }
+          else
+          {
             fprintf (pnm_file, "%ld ", (long) *pix_ptr++);
           }
+        }
+      }
       if (alpha_present)
       {
         if (!alpha)
         {
-          pix_ptr++; /* alpha */
+          /* skip the alpha-channel */
+          pix_ptr++;
           if (bit_depth == 16)
             pix_ptr++;
         }
-        else /* output alpha-channel as pgm file */
-        {
-          if (raw)
-            fputc ((int) *pix_ptr++ , alpha_file);
         else
-            if (bit_depth == 16){
+        {
-              dep_16 = (long) *pix_ptr++;
+          /* output the alpha-channel as pgm file */
-              fprintf (alpha_file, "%ld ", (dep_16 << 8) + (long) *pix_ptr++);
+          if (raw)
+          {
+            fputc ((int) *pix_ptr++, alpha_file);
+            if (bit_depth == 16)
+              fputc ((int) *pix_ptr++, alpha_file);
           }
           else
+          {
+            if (bit_depth == 16)
+            {
+              dep_16 = ((long) *pix_ptr++) << 8;
+              dep_16 += ((long) *pix_ptr++);
+              fprintf (alpha_file, "%ld ", dep_16);
+            }
+            else
+            {
               fprintf (alpha_file, "%ld ", (long) *pix_ptr++);
             }
-      } /* if alpha_present */
+          }
+        }
+      } /* end if alpha_present */
 
       if (!raw)
         if (col % 4 == 3)
@@ -427,12 +383,5 @@ BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file,
         fprintf (pnm_file, "\n");
   } /* end for row */
 
-  if (row_pointers != (unsigned char**) NULL)
-    free (row_pointers);
-  if (png_pixels != (unsigned char*) NULL)
-    free (png_pixels);
-
   return TRUE;
-
 } /* end of source */
-

contrib/pngminus/pnm2png.c

@@ -1,74 +1,57 @@
 /*
  *  pnm2png.c --- conversion from PBM/PGM/PPM-file to PNG-file
- *  copyright (C) 1999 by Willem van Schaik <willem at schaik.com>
+ *  copyright (C) 1999-2019 by Willem van Schaik <willem at schaik dot com>
  *
- *  version 1.0 - 1999.10.15 - First version.
+ *  This software is released under the MIT license. For conditions of
- *  version 1.1 - 2015.07.29 - Fixed leaks (Glenn Randers-Pehrson)
+ *  distribution and use, see the LICENSE file part of this package.
- *
- *  Permission to use, copy, modify, and distribute this software and
- *  its documentation for any purpose and without fee is hereby granted,
- *  provided that the above copyright notice appear in all copies and
- *  that both that copyright notice and this permission notice appear in
- *  supporting documentation. This software is provided "as is" without
- *  express or implied warranty.
  */
 
+#include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
-#ifdef __TURBOC__
-#include <mem.h>
 #include <fcntl.h>
-#endif
-#include <zlib.h>
 
 #ifndef BOOL
 #define BOOL unsigned char
 #endif
 #ifndef TRUE
-#define TRUE (BOOL) 1
+#define TRUE ((BOOL) 1)
 #endif
 #ifndef FALSE
-#define FALSE (BOOL) 0
+#define FALSE ((BOOL) 0)
-#endif
-
-#define STDIN  0
-#define STDOUT 1
-#define STDERR 2
-
-/* to make pnm2png verbose so we can find problems (needs to be before png.h) */
-#ifndef PNG_DEBUG
-#define PNG_DEBUG 0
 #endif
 
 #include "png.h"
 
-/* Define png_jmpbuf() in case we are using a pre-1.0.6 version of libpng */
-#ifndef png_jmpbuf
-#  define png_jmpbuf(png_ptr) ((png_ptr)->jmpbuf)
-#endif
-
 /* function prototypes */
 
 int main (int argc, char *argv[]);
 void usage ();
-BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,
+BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file,
-    BOOL alpha);
+              BOOL interlace, BOOL alpha);
-void get_token(FILE *pnm_file, char *token);
+BOOL do_pnm2png (png_struct *png_ptr, png_info *info_ptr,
-png_uint_32 get_data (FILE *pnm_file, int depth);
+                 FILE *pnm_file, FILE *alpha_file,
-png_uint_32 get_value (FILE *pnm_file, int depth);
+                 BOOL interlace, BOOL alpha);
+int fscan_pnm_magic (FILE *pnm_file, char *magic_buf, size_t magic_buf_size);
+int fscan_pnm_token (FILE *pnm_file, char *token_buf, size_t token_buf_size);
+int fscan_pnm_uint_32 (FILE *pnm_file, png_uint_32 *num_ptr);
+png_uint_32 get_pnm_data (FILE *pnm_file, int depth);
+png_uint_32 get_pnm_value (FILE *pnm_file, int depth);
 
 /*
  *  main
  */
 
-int main(int argc, char *argv[])
+int main (int argc, char *argv[])
 {
   FILE *fp_rd = stdin;
   FILE *fp_al = NULL;
   FILE *fp_wr = stdout;
+  const char *fname_wr = NULL;
   BOOL interlace = FALSE;
   BOOL alpha = FALSE;
   int argi;
+  int ret;
 
   for (argi = 1; argi < argc; argi++)
   {
@@ -92,14 +75,14 @@ int main(int argc, char *argv[])
           break;
         case 'h':
         case '?':
-          usage();
+          usage ();
-          exit(0);
+          exit (0);
           break;
         default:
           fprintf (stderr, "PNM2PNG\n");
           fprintf (stderr, "Error:  unknown option %s\n", argv[argi]);
-          usage();
+          usage ();
-          exit(1);
+          exit (1);
           break;
       } /* end switch */
     }
@@ -114,10 +97,11 @@ int main(int argc, char *argv[])
     }
     else if (fp_wr == stdout)
     {
+      fname_wr = argv[argi];
       if ((fp_wr = fopen (argv[argi], "wb")) == NULL)
       {
         fprintf (stderr, "PNM2PNG\n");
-        fprintf (stderr, "Error:  can not create PNG-file %s\n", argv[argi]);
+        fprintf (stderr, "Error:  cannot create PNG-file %s\n", argv[argi]);
         exit (1);
       }
     }
@@ -125,30 +109,23 @@ int main(int argc, char *argv[])
     {
       fprintf (stderr, "PNM2PNG\n");
       fprintf (stderr, "Error:  too many parameters\n");
-      usage();
+      usage ();
       exit (1);
     }
   } /* end for */
 
-#ifdef __TURBOC__
+#if defined(O_BINARY) && (O_BINARY != 0)
-  /* set stdin/stdout to binary, we're reading the PNM always! in binary format */
+  /* set stdin/stdout to binary,
+   * we're reading the PNM always! in binary format
+   */
   if (fp_rd == stdin)
-  {
+    setmode (fileno (stdin), O_BINARY);
-    setmode (STDIN, O_BINARY);
-  }
   if (fp_wr == stdout)
-  {
+    setmode (fileno (stdout), O_BINARY);
-    setmode (STDOUT, O_BINARY);
-  }
 #endif
 
   /* call the conversion program itself */
-  if (pnm2png (fp_rd, fp_wr, fp_al, interlace, alpha) == FALSE)
+  ret = pnm2png (fp_rd, fp_wr, fp_al, interlace, alpha);
-  {
-    fprintf (stderr, "PNM2PNG\n");
-    fprintf (stderr, "Error:  unsuccessful converting to PNG-image\n");
-    exit (1);
-  }
 
   /* close input file */
   fclose (fp_rd);
@@ -158,6 +135,15 @@ int main(int argc, char *argv[])
   if (alpha)
     fclose (fp_al);
 
+  if (!ret)
+  {
+    fprintf (stderr, "PNM2PNG\n");
+    fprintf (stderr, "Error:  unsuccessful converting to PNG-image\n");
+    if (fname_wr)
+      remove (fname_wr); /* no broken output file shall remain behind */
+    exit (1);
+  }
+
   return 0;
 }
 
@@ -165,15 +151,10 @@ int main(int argc, char *argv[])
  *  usage
  */
 
-void usage()
+void usage ()
 {
   fprintf (stderr, "PNM2PNG\n");
   fprintf (stderr, "   by Willem van Schaik, 1999\n");
-#ifdef __TURBOC__
-  fprintf (stderr, "   for Turbo-C and Borland-C compilers\n");
-#else
-  fprintf (stderr, "   for Linux (and Unix) compilers\n");
-#endif
   fprintf (stderr, "Usage:  pnm2png [options] <file>.<pnm> [<file>.png]\n");
   fprintf (stderr, "   or:  ... | pnm2png [options]\n");
   fprintf (stderr, "Options:\n");
@@ -187,103 +168,120 @@ void usage()
  *  pnm2png
  */
 
-BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,
+BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file,
-     BOOL alpha)
+              BOOL interlace, BOOL alpha)
 {
-  png_struct    *png_ptr = NULL;
+  png_struct    *png_ptr;
-  png_info      *info_ptr = NULL;
+  png_info      *info_ptr;
-  png_byte      *png_pixels = NULL;
+  BOOL          ret;
-  png_byte      **row_pointers = NULL;
-  png_byte      *pix_ptr = NULL;
-  volatile png_uint_32   row_bytes;
 
-  char          type_token[16];
+  /* initialize the libpng context for writing to png_file */
-  char          width_token[16];
+
-  char          height_token[16];
+  png_ptr = png_create_write_struct (png_get_libpng_ver(NULL),
-  char          maxval_token[16];
+                                     NULL, NULL, NULL);
-  volatile int    color_type=1;
+  if (!png_ptr)
-  unsigned long   ul_width=0, ul_alpha_width=0;
+    return FALSE; /* out of memory */
-  unsigned long   ul_height=0, ul_alpha_height=0;
+
-  unsigned long   ul_maxval=0;
+  info_ptr = png_create_info_struct (png_ptr);
-  volatile png_uint_32   width=0, height=0;
+  if (!info_ptr)
-  volatile png_uint_32   alpha_width=0, alpha_height=0;
+  {
-  png_uint_32   maxval;
+    png_destroy_write_struct (&png_ptr, NULL);
-  volatile int           bit_depth = 0;
+    return FALSE; /* out of memory */
-  int           channels=0;
+  }
-  int           alpha_depth = 0;
+
-  int           alpha_present=0;
+  if (setjmp (png_jmpbuf (png_ptr)))
-  int           row, col;
+  {
-  BOOL          raw, alpha_raw = FALSE;
+    png_destroy_write_struct (&png_ptr, &info_ptr);
-#if defined(PNG_WRITE_INVERT_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
+    return FALSE; /* generic libpng error */
+  }
+
+  png_init_io (png_ptr, png_file);
+
+  /* do the actual conversion */
+  ret = do_pnm2png (png_ptr, info_ptr, pnm_file, alpha_file, interlace, alpha);
+
+  /* clean up the libpng structures and their internally-managed data */
+  png_destroy_write_struct (&png_ptr, &info_ptr);
+
+  return ret;
+}
+
+/*
+ *  do_pnm2png - does the conversion in a fully-initialized libpng context
+ */
+
+BOOL do_pnm2png (png_struct *png_ptr, png_info *info_ptr,
+                 FILE *pnm_file, FILE *alpha_file,
+                 BOOL interlace, BOOL alpha)
+{
+  png_byte      **row_pointers;
+  png_byte      *pix_ptr;
+  int           bit_depth;
+  int           color_type;
+  int           channels;
+  char          magic_token[4];
+  BOOL          raw;
+  png_uint_32   width, height, maxval;
+  png_uint_32   row_bytes;
+  png_uint_32   row, col;
+  png_uint_32   val16, i;
+  png_uint_32   alpha_width = 0, alpha_height = 0;
+  int           alpha_depth = 0, alpha_present = 0;
+  BOOL          alpha_raw = FALSE;
   BOOL          packed_bitmap = FALSE;
-#endif
-  png_uint_32   tmp16;
-  int           i;
 
   /* read header of PNM file */
 
-  get_token(pnm_file, type_token);
+  if (fscan_pnm_magic (pnm_file, magic_token, sizeof (magic_token)) != 1)
-  if (type_token[0] != 'P')
+    return FALSE; /* not a PNM file */
+
+  if ((magic_token[1] == '1') || (magic_token[1] == '4'))
   {
+    if ((fscan_pnm_uint_32 (pnm_file, &width) != 1) ||
+        (fscan_pnm_uint_32 (pnm_file, &height) != 1))
+      return FALSE; /* bad PBM file header */
+  } else if ((magic_token[1] == '2') || (magic_token[1] == '5') ||
+             (magic_token[1] == '3') || (magic_token[1] == '6'))
+  {
+    if ((fscan_pnm_uint_32 (pnm_file, &width) != 1) ||
+        (fscan_pnm_uint_32 (pnm_file, &height) != 1) ||
+        (fscan_pnm_uint_32 (pnm_file, &maxval) != 1))
+      return FALSE; /* bad PGM/PPM file header */
+  }
+
+  if ((magic_token[1] == '1') || (magic_token[1] == '4'))
+  {
+    raw = (magic_token[1] == '4');
+    bit_depth = 1;
+    color_type = PNG_COLOR_TYPE_GRAY;
+    packed_bitmap = TRUE;
+  }
+  else if ((magic_token[1] == '2') || (magic_token[1] == '5'))
+  {
+    raw = (magic_token[1] == '5');
+    color_type = PNG_COLOR_TYPE_GRAY;
+    if (maxval == 0)
+      return FALSE;
+    else if (maxval == 1)
+      bit_depth = 1;
+    else if (maxval <= 3)
+      bit_depth = 2;
+    else if (maxval <= 15)
+      bit_depth = 4;
+    else if (maxval <= 255)
+      bit_depth = 8;
+    else if (maxval <= 65535U)
+      bit_depth = 16;
+    else /* maxval > 65535U */
       return FALSE;
   }
-  else if ((type_token[1] == '1') || (type_token[1] == '4'))
+  else if ((magic_token[1] == '3') || (magic_token[1] == '6'))
   {
-#if defined(PNG_WRITE_INVERT_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
+    raw = (magic_token[1] == '6');
-    raw = (type_token[1] == '4');
-    color_type = PNG_COLOR_TYPE_GRAY;
-    get_token(pnm_file, width_token);
-    sscanf (width_token, "%lu", &ul_width);
-    width = (png_uint_32) ul_width;
-    get_token(pnm_file, height_token);
-    sscanf (height_token, "%lu", &ul_height);
-    height = (png_uint_32) ul_height;
-    bit_depth = 1;
-    packed_bitmap = TRUE;
-#else
-    fprintf (stderr, "PNM2PNG built without PNG_WRITE_INVERT_SUPPORTED and \n");
-    fprintf (stderr, "PNG_WRITE_PACK_SUPPORTED can't read PBM (P1,P4) files\n");
-#endif
-  }
-  else if ((type_token[1] == '2') || (type_token[1] == '5'))
-  {
-    raw = (type_token[1] == '5');
-    color_type = PNG_COLOR_TYPE_GRAY;
-    get_token(pnm_file, width_token);
-    sscanf (width_token, "%lu", &ul_width);
-    width = (png_uint_32) ul_width;
-    get_token(pnm_file, height_token);
-    sscanf (height_token, "%lu", &ul_height);
-    height = (png_uint_32) ul_height;
-    get_token(pnm_file, maxval_token);
-    sscanf (maxval_token, "%lu", &ul_maxval);
-    maxval = (png_uint_32) ul_maxval;
-
-    if (maxval <= 1)
-      bit_depth = 1;
-    else if (maxval <= 3)
-      bit_depth = 2;
-    else if (maxval <= 15)
-      bit_depth = 4;
-    else if (maxval <= 255)
-      bit_depth = 8;
-    else /* if (maxval <= 65535) */
-      bit_depth = 16;
-  }
-  else if ((type_token[1] == '3') || (type_token[1] == '6'))
-  {
-    raw = (type_token[1] == '6');
     color_type = PNG_COLOR_TYPE_RGB;
-    get_token(pnm_file, width_token);
+    if (maxval == 0)
-    sscanf (width_token, "%lu", &ul_width);
+      return FALSE;
-    width = (png_uint_32) ul_width;
+    else if (maxval == 1)
-    get_token(pnm_file, height_token);
-    sscanf (height_token, "%lu", &ul_height);
-    height = (png_uint_32) ul_height;
-    get_token(pnm_file, maxval_token);
-    sscanf (maxval_token, "%lu", &ul_maxval);
-    maxval = (png_uint_32) ul_maxval;
-    if (maxval <= 1)
       bit_depth = 1;
     else if (maxval <= 3)
       bit_depth = 2;
@@ -291,8 +289,15 @@ BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,
       bit_depth = 4;
     else if (maxval <= 255)
       bit_depth = 8;
-    else /* if (maxval <= 65535) */
+    else if (maxval <= 65535U)
       bit_depth = 16;
+    else /* maxval > 65535U */
+      return FALSE;
+  }
+  else if (magic_token[1] == '7')
+  {
+    fprintf (stderr, "PNM2PNG can't read PAM (P7) files\n");
+    return FALSE;
   }
   else
   {
@@ -303,33 +308,23 @@ BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,
 
   if (alpha)
   {
-    if (color_type == PNG_COLOR_TYPE_GRAY)
+    if ((fscan_pnm_magic (alpha_file, magic_token, sizeof (magic_token)) != 1)
-      color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
+        || ((magic_token[1] != '2') && (magic_token[1] != '5')))
-    if (color_type == PNG_COLOR_TYPE_RGB)
+      return FALSE; /* not a PGM file */
-      color_type = PNG_COLOR_TYPE_RGB_ALPHA;
 
-    get_token(alpha_file, type_token);
+    if ((fscan_pnm_uint_32 (alpha_file, &alpha_width) != 1) ||
-    if (type_token[0] != 'P')
+        (fscan_pnm_uint_32 (alpha_file, &alpha_height) != 1) ||
-    {
+        (fscan_pnm_uint_32 (alpha_file, &maxval) != 1))
+      return FALSE; /* bad PGM file header */
+
+    if ((alpha_width != width) || (alpha_height != height))
+      return FALSE; /* mismatched PGM dimensions */
+
+    alpha_raw = (magic_token[1] == '5');
+    color_type |= PNG_COLOR_MASK_ALPHA;
+    if (maxval == 0)
       return FALSE;
-    }
+    else if (maxval == 1)
-    else if ((type_token[1] == '2') || (type_token[1] == '5'))
-    {
-      alpha_raw = (type_token[1] == '5');
-      get_token(alpha_file, width_token);
-      sscanf (width_token, "%lu", &ul_alpha_width);
-      alpha_width=(png_uint_32) ul_alpha_width;
-      if (alpha_width != width)
-        return FALSE;
-      get_token(alpha_file, height_token);
-      sscanf (height_token, "%lu", &ul_alpha_height);
-      alpha_height = (png_uint_32) ul_alpha_height;
-      if (alpha_height != height)
-        return FALSE;
-      get_token(alpha_file, maxval_token);
-      sscanf (maxval_token, "%lu", &ul_maxval);
-      maxval = (png_uint_32) ul_maxval;
-      if (maxval <= 1)
       alpha_depth = 1;
     else if (maxval <= 3)
       alpha_depth = 2;
@@ -337,15 +332,12 @@ BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,
       alpha_depth = 4;
     else if (maxval <= 255)
       alpha_depth = 8;
-      else /* if (maxval <= 65535) */
+    else if (maxval <= 65535U)
       alpha_depth = 16;
+    else /* maxval > 65535U */
+      return FALSE;
     if (alpha_depth != bit_depth)
       return FALSE;
-    }
-    else
-    {
-      return FALSE;
-    }
   } /* end if alpha */
 
   /* calculate the number of channels and store alpha-presence */
@@ -357,210 +349,259 @@ BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,
     channels = 3;
   else if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
     channels = 4;
-#if 0
   else
-    channels = 0; /* cannot happen */
+    return FALSE; /* NOTREACHED */
-#endif
 
   alpha_present = (channels - 1) % 2;
 
-#if defined(PNG_WRITE_INVERT_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
   if (packed_bitmap)
+  {
     /* row data is as many bytes as can fit width x channels x bit_depth */
     row_bytes = (width * channels * bit_depth + 7) / 8;
+  }
   else
-#endif
+  {
     /* row_bytes is the width x number of channels x (bit-depth / 8) */
     row_bytes = width * channels * ((bit_depth <= 8) ? 1 : 2);
+  }
 
-  if ((png_pixels = (png_byte *)
+  if ((row_bytes == 0) ||
-     malloc (row_bytes * height * sizeof (png_byte))) == NULL)
+      ((size_t) height > (size_t) (-1) / (size_t) row_bytes))
+  {
+    /* too big */
     return FALSE;
+  }
 
-  /* read data from PNM file */
+  /* allocate the rows using the same memory layout as libpng, and transfer
-  pix_ptr = png_pixels;
+   * their ownership to libpng, with the responsibility to clean everything up;
-
+   * please note the use of png_calloc instead of png_malloc */
-  for (row = 0; row < (int) height; row++)
+  row_pointers = (png_byte **)
+                 png_calloc (png_ptr, height * sizeof (png_byte *));
+  png_set_rows (png_ptr, info_ptr, row_pointers);
+  png_data_freer (png_ptr, info_ptr, PNG_DESTROY_WILL_FREE_DATA, PNG_FREE_ALL);
+  for (row = 0; row < height; row++)
+  {
+    /* the individual rows should only be allocated after all the previous
+     * steps completed successfully, because libpng must handle correctly
+     * any image allocation left incomplete after an out-of-memory error */
+    row_pointers[row] = (png_byte *) png_malloc (png_ptr, row_bytes);
+  }
+
+  /* read the data from PNM file */
+
+  for (row = 0; row < height; row++)
+  {
+    pix_ptr = row_pointers[row];
+    if (packed_bitmap)
+    {
+      for (i = 0; i < row_bytes; i++)
       {
-#if defined(PNG_WRITE_INVERT_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
-    if (packed_bitmap) {
-      for (i = 0; i < (int) row_bytes; i++)
         /* png supports this format natively so no conversion is needed */
-        *pix_ptr++ = get_data (pnm_file, 8);
+        *pix_ptr++ = get_pnm_data (pnm_file, 8);
-    } else
+      }
-#endif
+    }
+    else
     {
-      for (col = 0; col < (int) width; col++)
+      for (col = 0; col < width; col++)
       {
-        for (i = 0; i < (channels - alpha_present); i++)
+        for (i = 0; i < (png_uint_32) (channels - alpha_present); i++)
         {
           if (raw)
-            *pix_ptr++ = get_data (pnm_file, bit_depth);
+          {
-          else
+            *pix_ptr++ = get_pnm_data (pnm_file, bit_depth);
-            if (bit_depth <= 8)
+            if (bit_depth == 16)
-              *pix_ptr++ = get_value (pnm_file, bit_depth);
+              *pix_ptr++ = get_pnm_data (pnm_file, bit_depth);
+          }
           else
           {
-              tmp16 = get_value (pnm_file, bit_depth);
+            if (bit_depth <= 8)
-              *pix_ptr = (png_byte) ((tmp16 >> 8) & 0xFF);
+            {
+              *pix_ptr++ = get_pnm_value (pnm_file, bit_depth);
+            }
+            else
+            {
+              val16 = get_pnm_value (pnm_file, bit_depth);
+              *pix_ptr = (png_byte) ((val16 >> 8) & 0xFF);
               pix_ptr++;
-              *pix_ptr = (png_byte) (tmp16 & 0xFF);
+              *pix_ptr = (png_byte) (val16 & 0xFF);
               pix_ptr++;
             }
           }
+        }
 
         if (alpha) /* read alpha-channel from pgm file */
         {
           if (alpha_raw)
-            *pix_ptr++ = get_data (alpha_file, alpha_depth);
+          {
-          else
+            *pix_ptr++ = get_pnm_data (alpha_file, alpha_depth);
-            if (alpha_depth <= 8)
+            if (alpha_depth == 16)
-              *pix_ptr++ = get_value (alpha_file, bit_depth);
+              *pix_ptr++ = get_pnm_data (alpha_file, alpha_depth);
+          }
           else
           {
-              tmp16 = get_value (alpha_file, bit_depth);
+            if (alpha_depth <= 8)
-              *pix_ptr++ = (png_byte) ((tmp16 >> 8) & 0xFF);
+            {
-              *pix_ptr++ = (png_byte) (tmp16 & 0xFF);
+              *pix_ptr++ = get_pnm_value (alpha_file, bit_depth);
             }
-        } /* if alpha */
+            else
-      } /* if packed_bitmap */
+            {
+              val16 = get_pnm_value (alpha_file, bit_depth);
+              *pix_ptr++ = (png_byte) ((val16 >> 8) & 0xFF);
+              *pix_ptr++ = (png_byte) (val16 & 0xFF);
+            }
+          }
+        } /* end if alpha */
+      } /* end if packed_bitmap */
     } /* end for col */
   } /* end for row */
 
-  /* prepare the standard PNG structures */
-  png_ptr = png_create_write_struct (png_get_libpng_ver(NULL), NULL, NULL,
-      NULL);
-  if (!png_ptr)
-  {
-    free (png_pixels);
-    png_pixels = NULL;
-    return FALSE;
-  }
-  info_ptr = png_create_info_struct (png_ptr);
-  if (!info_ptr)
-  {
-    png_destroy_write_struct (&png_ptr, (png_infopp) NULL);
-    free (png_pixels);
-    png_pixels = NULL;
-    return FALSE;
-  }
-
-#if defined(PNG_WRITE_INVERT_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
-  if (packed_bitmap == TRUE)
-  {
-    png_set_packing (png_ptr);
-    png_set_invert_mono (png_ptr);
-  }
-#endif
-
-  /* setjmp() must be called in every function that calls a PNG-reading libpng function */
-  if (setjmp (png_jmpbuf(png_ptr)))
-  {
-    png_destroy_write_struct (&png_ptr, &info_ptr);
-    free (png_pixels);
-    png_pixels = NULL;
-    return FALSE;
-  }
-
-  /* initialize the png structure */
-  png_init_io (png_ptr, png_file);
-
   /* we're going to write more or less the same PNG as the input file */
   png_set_IHDR (png_ptr, info_ptr, width, height, bit_depth, color_type,
                 (!interlace) ? PNG_INTERLACE_NONE : PNG_INTERLACE_ADAM7,
                 PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
 
+  if (packed_bitmap == TRUE)
+  {
+    png_set_packing (png_ptr);
+    png_set_invert_mono (png_ptr);
+  }
+
   /* write the file header information */
   png_write_info (png_ptr, info_ptr);
 
-  /* if needed we will allocate memory for an new array of row-pointers */
-  if (row_pointers == (unsigned char**) NULL)
-  {
-    if ((row_pointers = (png_byte **)
-        malloc (height * sizeof (png_bytep))) == NULL)
-    {
-      png_destroy_write_struct (&png_ptr, &info_ptr);
-      free (png_pixels);
-      png_pixels = NULL;
-      return FALSE;
-    }
-  }
-
-  /* set the individual row_pointers to point at the correct offsets */
-  for (i = 0; i < (int) height; i++)
-    row_pointers[i] = png_pixels + i * row_bytes;
-
   /* write out the entire image data in one call */
   png_write_image (png_ptr, row_pointers);
 
   /* write the additional chunks to the PNG file (not really needed) */
   png_write_end (png_ptr, info_ptr);
 
-  /* clean up after the write, and free any memory allocated */
-  png_destroy_write_struct (&png_ptr, &info_ptr);
-
-  if (row_pointers != (unsigned char**) NULL)
-    free (row_pointers);
-  if (png_pixels != (unsigned char*) NULL)
-    free (png_pixels);
-
   return TRUE;
 } /* end of pnm2png */
 
 /*
- * get_token() - gets the first string after whitespace
+ * fscan_pnm_magic - like fscan_pnm_token below, but expects the magic string
+ *                   to start immediately, without any comment or whitespace,
+ *                   and to match the regex /^P[1-9]$/
  */
 
-void get_token(FILE *pnm_file, char *token)
+int fscan_pnm_magic (FILE *pnm_file, char *magic_buf, size_t magic_buf_size)
 {
-  int i = 0;
+  int ret;
+
+  ret = fgetc (pnm_file);
+  if (ret == EOF) return 0;
+  ungetc (ret, pnm_file);
+  if (ret != 'P') return 0;
+
+  /* the string buffer must be at least four bytes long, i.e., the capacity
+   * required for strings of at least three characters long, i.e., the minimum
+   * required for ensuring that our magic string is exactly two characters long
+   */
+  if (magic_buf_size < 4) return -1;
+
+  ret = fscan_pnm_token (pnm_file, magic_buf, magic_buf_size);
+  if (ret < 1) return ret;
+
+  if ((magic_buf[1] < '1') || (magic_buf[1] > '9')) return 0;
+  if (magic_buf[2] != '\0') return 0;
+
+  return 1;
+}
+
+/*
+ * fscan_pnm_token - extracts the first string token after whitespace,
+ *                   and (like fscanf) returns the number of successful
+ *                   extractions, which can be either 0 or 1
+ */
+
+int fscan_pnm_token (FILE *pnm_file, char *token_buf, size_t token_buf_size)
+{
+  size_t i = 0;
   int ret;
 
   /* remove white-space and comment lines */
   do
   {
-    ret = fgetc(pnm_file);
+    ret = fgetc (pnm_file);
-    if (ret == '#') {
+    if (ret == '#')
+    {
       /* the rest of this line is a comment */
       do
       {
-        ret = fgetc(pnm_file);
+        ret = fgetc (pnm_file);
       }
       while ((ret != '\n') && (ret != '\r') && (ret != EOF));
     }
     if (ret == EOF) break;
-    token[i] = (unsigned char) ret;
+    token_buf[i] = (char) ret;
   }
-  while ((token[i] == '\n') || (token[i] == '\r') || (token[i] == ' '));
+  while ((ret == '\n') || (ret == '\r') || (ret == ' '));
 
   /* read string */
   do
   {
-    ret = fgetc(pnm_file);
+    ret = fgetc (pnm_file);
     if (ret == EOF) break;
-    i++;
+    if (ret == '0')
-    token[i] = (unsigned char) ret;
+    {
+      /* avoid storing more than one leading '0' in the token buffer,
+       * to ensure that all valid (in-range) numeric inputs can fit in. */
+      if ((i == 0) && (token_buf[i] == '0')) continue;
     }
-  while ((token[i] != '\n') && (token[i] != '\r') && (token[i] != ' '));
+    if (++i == token_buf_size - 1) break;
+    token_buf[i] = (char) ret;
+  }
+  while ((ret != '\n') && (ret != '\r') && (ret != ' '));
 
-  token[i] = '\0';
+  token_buf[i] = '\0';
-
+  return (i > 0) ? 1 : 0;
-  return;
 }
 
 /*
- * get_data() - takes first byte and converts into next pixel value,
+ * fscan_pnm_uint_32 - like fscan_token above, but expects the extracted token
- *        taking as much bits as defined by bit-depth and
+ *                     to be numeric, and converts it to an unsigned 32-bit int
- *        using the bit-depth to fill up a byte (0Ah -> AAh)
  */
 
-png_uint_32 get_data (FILE *pnm_file, int depth)
+int fscan_pnm_uint_32 (FILE *pnm_file, png_uint_32 *num_ptr)
+{
+  char token[16];
+  unsigned long token_value;
+  int ret;
+
+  ret = fscan_pnm_token (pnm_file, token, sizeof (token));
+  if (ret < 1) return ret;
+
+  if ((token[0] < '0') && (token[0] > '9'))
+    return 0; /* the token starts with junk, or a +/- sign, which is invalid */
+
+  ret = sscanf (token, "%lu%*c", &token_value);
+  if (ret != 1)
+    return 0; /* the token ends with junk */
+
+  *num_ptr = (png_uint_32) token_value;
+
+#if ULONG_MAX > 0xFFFFFFFFUL
+  /* saturate the converted number, following the fscanf convention */
+  if (token_value > 0xFFFFFFFFUL)
+    *num_ptr = 0xFFFFFFFFUL;
+#endif
+
+  return 1;
+}
+
+/*
+ *  get_pnm_data - takes first byte and converts into next pixel value,
+ *                 taking as many bits as defined by bit-depth and
+ *                 using the bit-depth to fill up a byte (0x0A -> 0xAA)
+ */
+
+png_uint_32 get_pnm_data (FILE *pnm_file, int depth)
 {
   static int bits_left = 0;
   static int old_value = 0;
   static int mask = 0;
-  int i;
   png_uint_32 ret_value;
+  int i;
 
   if (mask == 0)
     for (i = 0; i < depth; i++)
@@ -568,7 +609,11 @@ png_uint_32 get_data (FILE *pnm_file, int depth)
 
   if (bits_left <= 0)
   {
+    /* FIXME:
+     * signal the premature end of file, instead of pretending to read zeroes
+     */
     old_value = fgetc (pnm_file);
+    if (old_value == EOF) return 0;
     bits_left = 8;
   }
 
@@ -583,25 +628,28 @@ png_uint_32 get_data (FILE *pnm_file, int depth)
 }
 
 /*
- * get_value() - takes first (numeric) string and converts into number,
+ *  get_pnm_value - takes first (numeric) string and converts into number,
- *         using the bit-depth to fill up a byte (0Ah -> AAh)
+ *                  using the bit-depth to fill up a byte (0x0A -> 0xAA)
  */
 
-png_uint_32 get_value (FILE *pnm_file, int depth)
+png_uint_32 get_pnm_value (FILE *pnm_file, int depth)
 {
   static png_uint_32 mask = 0;
-  png_byte token[16];
-  unsigned long ul_ret_value;
   png_uint_32 ret_value;
-  int i = 0;
+  int i;
 
   if (mask == 0)
     for (i = 0; i < depth; i++)
       mask = (mask << 1) | 0x01;
 
-  get_token (pnm_file, (char *) token);
+  if (fscan_pnm_uint_32 (pnm_file, &ret_value) != 1)
-  sscanf ((const char *) token, "%lu", &ul_ret_value);
+  {
-  ret_value = (png_uint_32) ul_ret_value;
+    /* FIXME:
+     * signal the invalid numeric tokens or the premature end of file,
+     * instead of pretending to read zeroes
+     */
+    return 0;
+  }
 
   ret_value &= mask;
 
@@ -613,4 +661,3 @@ png_uint_32 get_value (FILE *pnm_file, int depth)
 }
 
 /* end of source */
-

contrib/pngminus/test_png2pnm.bat

@@ -7,7 +7,7 @@ png2pnm.exe -noraw ..\pngsuite\basn0g16.png basn0g16.pgm
 REM -- full-color
 png2pnm.exe -noraw ..\pngsuite\basn2c08.png basn2c08.ppm
 png2pnm.exe -noraw ..\pngsuite\basn2c16.png basn2c16.ppm
-REM -- palletted
+REM -- paletted
 png2pnm.exe -noraw ..\pngsuite\basn3p01.png basn3p01.ppm
 png2pnm.exe -noraw ..\pngsuite\basn3p02.png basn3p02.ppm
 png2pnm.exe -noraw ..\pngsuite\basn3p04.png basn3p04.ppm
@@ -27,7 +27,7 @@ png2pnm.exe -raw ..\pngsuite\basn0g16.png rawn0g16.pgm
 REM -- full-color
 png2pnm.exe -raw ..\pngsuite\basn2c08.png rawn2c08.ppm
 png2pnm.exe -raw ..\pngsuite\basn2c16.png rawn2c16.ppm
-REM -- palletted
+REM -- paletted
 png2pnm.exe -raw ..\pngsuite\basn3p01.png rawn3p01.ppm
 png2pnm.exe -raw ..\pngsuite\basn3p02.png rawn3p02.ppm
 png2pnm.exe -raw ..\pngsuite\basn3p04.png rawn3p04.ppm

contrib/pngminus/test_png2pnm.sh

@@ -8,7 +8,7 @@
 # -- full-color
 ./png2pnm -noraw ../pngsuite/basn2c08.png basn2c08.ppm
 ./png2pnm -noraw ../pngsuite/basn2c16.png basn2c16.ppm
-# -- palletted
+# -- paletted
 ./png2pnm -noraw ../pngsuite/basn3p01.png basn3p01.ppm
 ./png2pnm -noraw ../pngsuite/basn3p02.png basn3p02.ppm
 ./png2pnm -noraw ../pngsuite/basn3p04.png basn3p04.ppm
@@ -28,7 +28,7 @@
 # -- full-color
 ./png2pnm -raw ../pngsuite/basn2c08.png rawn2c08.ppm
 ./png2pnm -raw ../pngsuite/basn2c16.png rawn2c16.ppm
-# -- palletted
+# -- paletted
 ./png2pnm -raw ../pngsuite/basn3p01.png rawn3p01.ppm
 ./png2pnm -raw ../pngsuite/basn3p02.png rawn3p02.ppm
 ./png2pnm -raw ../pngsuite/basn3p04.png rawn3p04.ppm

contrib/pngminus/test_pngminus.bat

@@ -1,4 +1,4 @@
-make -f makefile.tc3
+make
 call png2pnm.bat
 call pnm2png.bat
 

contrib/pngminus/test_pngminus.sh

@@ -1,5 +1,5 @@
 #!/bin/sh
-make -f makefile.std
+make
 sh png2pnm.sh
 sh pnm2png.sh
 

contrib/pngminus/test_pnm2png.bat

@@ -7,7 +7,7 @@ pnm2png.exe basn0g16.pgm basn0g16.png
 REM -- full-color
 pnm2png.exe basn2c08.ppm basn2c08.png
 pnm2png.exe basn2c16.ppm basn2c16.png
-REM -- palletted
+REM -- paletted
 pnm2png.exe basn3p01.ppm basn3p01.png
 pnm2png.exe basn3p02.ppm basn3p02.png
 pnm2png.exe basn3p04.ppm basn3p04.png
@@ -27,7 +27,7 @@ pnm2png.exe rawn0g16.pgm rawn0g16.png
 REM -- full-color
 pnm2png.exe rawn2c08.ppm rawn2c08.png
 pnm2png.exe rawn2c16.ppm rawn2c16.png
-REM -- palletted
+REM -- paletted
 pnm2png.exe rawn3p01.ppm rawn3p01.png
 pnm2png.exe rawn3p02.ppm rawn3p02.png
 pnm2png.exe rawn3p04.ppm rawn3p04.png

contrib/pngminus/test_pnm2png.sh

@@ -8,7 +8,7 @@
 # -- full-color
 ./pnm2png basn2c08.ppm basn2c08.png
 ./pnm2png basn2c16.ppm basn2c16.png
-# -- palletted
+# -- paletted
 ./pnm2png basn3p01.ppm basn3p01.png
 ./pnm2png basn3p02.ppm basn3p02.png
 ./pnm2png basn3p04.ppm basn3p04.png
@@ -28,7 +28,7 @@
 # -- full-color
 ./pnm2png rawn2c08.ppm rawn2c08.png
 ./pnm2png rawn2c16.ppm rawn2c16.png
-# -- palletted
+# -- paletted
 ./pnm2png rawn3p01.ppm rawn3p01.png
 ./pnm2png rawn3p02.ppm rawn3p02.png
 ./pnm2png rawn3p04.ppm rawn3p04.png

contrib/pngsuite/README

@@ -16,6 +16,8 @@ chunks, etc.
 The "ft*.png" images are "free/libre" replacements for the transparent
 corresponding t*.png images in the PngSuite.
 
+The "i*.png" images are the same images, but interlaced.
+
 The images in this directory represent the basic PNG color-types:
 grayscale (1-16 bit deep), full color (8 or 16 bit), paletted
 (1-8 bit) and grayscale or color images with alpha channel. You

contrib/pngsuite/bad_interlace_conversions.txt

@@ -0,0 +1,9 @@
+basn0g01.png
+basn0g02.png
+basn0g04.png
+basn3p01.png
+basn3p02.png
+basn3p04.png
+ftbbn0g01.png
+ftbbn0g02.png
+ftbbn0g04.png