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

@@ -1,93 +1,66 @@
+libpng 1.6.41 - January 24, 2024
+================================
 
-Libpng 1.6.10 - March 6, 2014
+This is a public release of libpng, intended for use in production code.
 
-This is a public release of libpng, intended for use in production codes.
 
-Files available for download:
+Files available for download
+----------------------------
 
-Source files with LF line endings (for Unix/Linux) and with a
+Source files with LF line endings (for Unix/Linux):
-"configure" script
 
-   libpng-1.6.10.tar.xz (LZMA-compressed, recommended)
+ * libpng-1.6.41.tar.xz (LZMA-compressed, recommended)
-   libpng-1.6.10.tar.gz
+ * libpng-1.6.41.tar.gz (deflate-compressed)
 
-Source files with CRLF line endings (for Windows), without the
+Source files with CRLF line endings (for Windows):
-"configure" script
 
-   lpng1610.7z  (LZMA-compressed, recommended)
+ * lpng1641.7z (LZMA-compressed, recommended)
-   lpng1610.zip
+ * lpng1641.zip (deflate-compressed)
 
 Other information:
 
-   libpng-1.6.10-README.txt
+ * README.md
-   libpng-1.6.10-LICENSE.txt
+ * LICENSE.md
-   libpng-1.6.10-*.asc (armored detached GPG signatures)
+ * AUTHORS.md
+ * TRADEMARK.md
 
-Changes since the last public release (1.6.9):
-  Backported changes from libpng-1.7.0beta30 and beta31:
-  Fixed a large number of instances where PNGCBAPI was omitted from
-    function definitions.
-  Added pngimage test program for png_read_png() and png_write_png()
-    with two new test scripts.
-  Removed dependence on !PNG_READ_EXPAND_SUPPORTED for calling
-    png_set_packing() in png_read_png().
-  Fixed combination of ~alpha with shift. On read invert alpha, processing
-    occurred after shift processing, which causes the final values to be
-    outside the range that should be produced by the shift. Reversing the
-    order on read makes the two transforms work together correctly and mirrors
-    the order used on write.
-  Do not read invalid sBIT chunks. Previously libpng only checked sBIT
-    values on write, so a malicious PNG writer could therefore cause
-    the read code to return an invalid sBIT chunk, which might lead to
-    application errors or crashes.  Such chunks are now skipped (with
-    chunk_benign_error).
-  Make png_read_png() and png_write_png() prototypes in png.h depend
-    upon PNG_READ_SUPPORTED and PNG_WRITE_SUPPORTED.
-  Support builds with unsupported PNG_TRANSFORM_* values.  All of the
-    PNG_TRANSFORM_* values are always defined in png.h and, because they
-    are used for both read and write in some cases, it is not reliable
-    to #if out ones that are totally unsupported. This change adds error
-    detection in png_read_image() and png_write_image() to do a
-    png_app_error() if the app requests something that cannot be done
-    and it adds corresponding code to pngimage.c to handle such options
-    by not attempting to test them.
-  Moved redefines of png_error(), png_warning(), png_chunk_error(),
-    and png_chunk_warning() from pngpriv.h to png.h to make them visible
-    to libpng-calling applications.
-  Moved OS dependent code from arm/arm_init.c, to allow the included
-    implementation of the ARM NEON discovery function to be set at
-    build-time and provide sample implementations from the current code in the
-    contrib/arm-neon subdirectory. The __linux__ code has also been changed to
-    compile and link on Android by using /proc/cpuinfo, and the old linux code
-    is in contrib/arm-neon/linux-auxv.c.  The new code avoids POSIX and Linux
-    dependencies apart from opening /proc/cpuinfo and is C90 compliant.
-  Check for info_ptr == NULL early in png_read_end() so we don't need to
-    run all the png_handle_*() and depend on them to return if info_ptr == NULL.
-    This improves the performance of png_read_end(png_ptr, NULL) and makes
-    it more robust against future programming errors.
-  Check for __has_extension before using it in pngconf.h, to
-    support older Clang versions (Jeremy Sequoia).
-  Treat CRC error handling with png_set_crc_action(), instead of with
-    png_set_benign_errors(), which has been the case since libpng-1.6.0beta18.
-  Use a user warning handler in contrib/gregbook/readpng2.c instead of default,
-    so warnings will be put on stderr even if libpng has CONSOLE_IO disabled.
-  Added png_ptr->process_mode = PNG_READ_IDAT_MODE in png_push_read_chunk
-    after recognizing the IDAT chunk, which avoids an infinite loop while
-    reading a datastream whose first IDAT chunk is of zero-length.
-    This fixes CERT VU#684412 and CVE-2014-0333.
-  Don't recognize known sRGB profiles as sRGB if they have been hacked,
-    but don't reject them and don't issue a copyright violation warning.
-  Moved some documentation from png.h to libpng.3 and libpng-manual.txt
-  Minor editing of contrib/arm-neon/README and contrib/examples/*.c
-  Fixed typos in the manual and in scripts/pnglibconf.dfa (CFLAGS -> CPPFLAGS
-    and PNG_USR_CONFIG -> PNG_USER_CONFIG).
-  Un-deprecated png_data_freer().
 
-Send comments/corrections/commendations to png-mng-implement at lists.sf.net
+Changes from version 1.6.40 to version 1.6.41
-(subscription required; visit
+---------------------------------------------
+
+ * 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)
+to subscribe.
-or to glennrp at users.sourceforge.net
-
-Glenn R-P
-#endif

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.

INSTALL

@@ -1,5 +1,28 @@
 
-Installing libpng
+    Installing libpng
+
+Contents
+
+       I. Simple installation
+      II. Rebuilding the configure scripts
+     III. Using scripts/makefile*
+      IV. Using cmake
+       V. Directory structure
+      VI. Building with project files
+     VII. Building with makefiles
+    VIII. Configuring libpng for 16-bit platforms
+      IX. Configuring for DOS
+       X. Configuring for Medium Model
+      XI. Prepending a prefix to exported symbols
+     XII. Configuring for compiler xxx:
+    XIII. Removing unwanted object code
+     XIV. Enabling or disabling hardware optimizations
+      XV. Changes to the build and configuration of libpng in libpng-1.5.x
+     XVI. Setjmp/longjmp issues
+    XVII. Common linking failures
+   XVIII. Other sources of information about libpng
+
+I. Simple installation
 
 On Unix/Linux and similar systems, you can simply type
 
@@ -7,13 +30,28 @@ On Unix/Linux and similar systems, you can simply type
     make check
     make install
 
-and ignore the rest of this document.
+and ignore the rest of this document.  "/path" is the path to the directory
+where you want to install the libpng "lib", "include", and "bin"
+subdirectories.
+
+If you downloaded a GIT clone, you will need to run ./autogen.sh before
+running ./configure, to create "configure" and "Makefile.in" which are
+not included in the GIT repository.
+
+Note that "configure" is only included in the "*.tar" distributions and not
+in the "*.zip" or "*.7z" distributions. If you downloaded one of those
+distributions, see "Building with project files" or "Building with makefiles",
+below.
+
+II. Rebuilding the configure scripts
 
 If configure does not work on your system, or if you have a need to
 change configure.ac or Makefile.am, and you have a reasonably
 up-to-date set of tools, running ./autogen.sh in a git clone before
 running ./configure may fix the problem.  To be really sure that you
-aren't using any of the included pre-built scripts, you can do this:
+aren't using any of the included pre-built scripts, especially if you
+are building from a tar distribution instead of a git distribution,
+do this:
 
     ./configure --enable-maintainer-mode
     make maintainer-clean
@@ -24,9 +62,12 @@ aren't using any of the included pre-built scripts, you can do this:
     make install
     make check
 
+III. Using scripts/makefile*
+
 Instead, you can use one of the custom-built makefiles in the
 "scripts" directory
 
+    cp scripts/pnglibconf.h.prebuilt pnglibconf.h
     cp scripts/makefile.system makefile
     make test
     make install
@@ -38,8 +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.  zlib can be placed in another directory,
+wherever you got libpng; otherwise go to https://zlib.net/.  You can
-at the same level as libpng.
+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
@@ -50,49 +91,55 @@ standard library search path, put ZLIBLIB, ZLIBINC, CPPFLAGS, LDFLAGS,
 and LD_LIBRARY_PATH in your environment before running "make test"
 or "make distcheck":
 
-ZLIBLIB=/path/to/lib export ZLIBLIB
+    ZLIBLIB=/path/to/lib export ZLIBLIB
-ZLIBINC=/path/to/include export ZLIBINC
+    ZLIBINC=/path/to/include export ZLIBINC
-CPPFLAGS="-I$ZLIBINC" export CPPFLAGS
+    CPPFLAGS="-I$ZLIBINC" export CPPFLAGS
-LDFLAGS="-L$ZLIBLIB" export LDFLAGS
+    LDFLAGS="-L$ZLIBLIB" export LDFLAGS
-LD_LIBRARY_PATH="$ZLIBLIB:$LD_LIBRARY_PATH" export LD_LIBRARY_PATH
+    LD_LIBRARY_PATH="$ZLIBLIB:$LD_LIBRARY_PATH" export LD_LIBRARY_PATH
 
 If you are using one of the makefile scripts, put ZLIBLIB and ZLIBINC
-in your environment and type "make ZLIBLIB=$ZLIBLIB ZLIBINC=$ZLIBINC test".
+in your environment and type
+
+    make ZLIBLIB=$ZLIBLIB ZLIBINC=$ZLIBINC test
+
+IV. Using cmake
 
 If you want to use "cmake" (see www.cmake.org), type
 
-   cmake . -DCMAKE_INSTALL_PREFIX=/path
+    cmake . -DCMAKE_INSTALL_PREFIX=/path
-   make
+    make
-   make install
+    make install
+
+As when using the simple configure method described above, "/path" points to
+the installation directory where you want to put the libpng "lib", "include",
+and "bin" subdirectories.
+
+V. Directory structure
 
 You can rename the directories that you downloaded (they
-might be called "libpng-x.y.z" or "libpngNN" and "zlib-1.2.7"
+might be called "libpng-x.y.z" or "libpngNN" and "zlib-1.2.8"
-or "zlib127") so that you have directories called "zlib" and "libpng".
+or "zlib128") so that you have directories called "zlib" and "libpng".
 
 Your directory structure should look like this:
 
-   ..       (the parent directory)
+    .. (the parent directory)
-      libpng  (this directory)
+      libpng (this directory)
           INSTALL (this file)
           README
-          *.h
+          *.h, *.c  => libpng source files
-          *.c
           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
-             gregbook
+             arm-neon, conftest, examples, gregbook, libtests, pngminim,
-             libtests
+             pngminus, pngsuite, tools, visupng
-             pngminim
-             pngminus
-             pngsuite
-             visupng
           projects
-             visualc71
+             owatcom, visualc71, vstudio
-             vstudio
           scripts
              makefile.*
              *.def (module definition files)
@@ -100,29 +147,35 @@ Your directory structure should look like this:
           pngtest.png
           etc.
       zlib
-          README
+          README, *.h, *.c, contrib, etc.
-          *.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
 endings) and zip (DOS style line endings) formats.
 
-If you are building libpng with MSVC, you can enter the
+VI. Building with project files
-libpng projects\visualc6 or visualc71 directory and follow the instructions
-in README.txt.
 
-Otherwise enter the zlib directory and follow the instructions in zlib/README,
+If you are building libpng with Microsoft Visual Studio, you can enter
-then come back here and run "configure" or choose the appropriate
+the directory projects\visualc71 or projects\vstudio and follow the
-makefile.sys in the scripts directory.
+instructions in README.txt.
+
+Otherwise, enter the zlib directory and follow the instructions in
+zlib/README, then come back here and run "configure" or choose the
+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
+UNIX example:
-   UNIX example:    cp scripts/makefile.std makefile
+
+    cp scripts/makefile.std Makefile
+    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.
@@ -139,32 +192,273 @@ 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 for DOS and other 16-bit platforms
+
+Officially, the support for 16-bit platforms has been removed.
+
+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.
+
+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.
+
+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.
+You will also have to look into zconf.h to tell zlib (and thus libpng)
+that it cannot allocate more than 64K at a time.  Even if you can, the
+memory won't be accessible.  Therefore, you should limit zlib and libpng
+to 64K by defining MAXSEG_64K.
+
+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
+configuration option "--with-libpng-prefix=FOO_", where FOO_ can be any
+string beginning with a letter and containing only uppercase
+and lowercase letters, digits, and the underscore (i.e., a C language
+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.
+
+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.
+The includes that are not needed outside libpng are placed in pngpriv.h,
+which is only used by the routines inside libpng itself.
+The files in libpng proper only include pngpriv.h and png.h, which
+in turn includes pngconf.h and, as of libpng-1.5.0, pnglibconf.h.
+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.
+
+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
+never going to use a capability, you can change the #define to #undef
+before recompiling libpng and save yourself code and data space, or
+you can turn off individual capabilities with defines that begin with
+"PNG_NO_".
+
+In libpng-1.5.0 and later, the #define's are in pnglibconf.h instead.
+
+You can also turn all of the transforms and ancillary chunk capabilities
+off en masse with compiler directives that define
+PNG_NO_READ[or WRITE]_TRANSFORMS, or PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS,
+or all four, along with directives to turn on any of the capabilities that
+you do want.  The PNG_NO_READ[or WRITE]_TRANSFORMS directives disable the
+extra transformations but still leave the library fully capable of reading
+and writing PNG files with all known public chunks. Use of the
+PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS directive produces a library
+that is incapable of reading or writing ancillary chunks.  If you are
+not using the progressive reading capability, you can turn that off
+with PNG_NO_PROGRESSIVE_READ (don't confuse this with the INTERLACING
+capability, which you'll still have).
+
+All the reading and writing specific code are in separate files, so the
+linker should only grab the files it needs.  However, if you want to
+make sure, or if you are building a stand alone library, all the
+reading files start with "pngr" and all the writing files start with "pngw".
+The files that don't match either (like png.c, pngtrans.c, etc.)
+are used for both reading and writing, and always need to be included.
+The progressive reader is in pngpread.c
+
+If you are creating or distributing a dynamically linked library (a .so
+or DLL file), you should not remove or disable any parts of the library,
+as this will cause applications linked with different versions of the
+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.
+
+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
+majority of library users or builders; however, the few who configure libpng
+to a non-default feature set may need to change how this is done.
+
+There should be no need for library builders to alter build scripts if
+these use the distributed build support - configure or the makefiles -
+however, users of the makefiles may care to update their build scripts
+to build pnglibconf.h where the corresponding makefile does not do so.
+
+Building libpng with a non-default configuration has changed completely.
+The old method using pngusr.h should still work correctly even though the
+way pngusr.h is used in the build has been changed; however, library
+builders will probably want to examine the changes to take advantage of
+new capabilities and to simplify their build system.
+
+A. Specific changes to library configuration capabilities
+
+The exact mechanism used to control attributes of API functions has
+changed.  A single set of operating system independent macro definitions
+is used and operating system specific directives are defined in
+pnglibconf.h
+
+As part of this the mechanism used to choose procedure call standards on
+those systems that allow a choice has been changed.  At present this only
+affects certain Microsoft (DOS, Windows) and IBM (OS/2) operating systems
+running on Intel processors.  As before, PNGAPI is defined where required
+to control the exported API functions; however, two new macros, PNGCBAPI
+and PNGCAPI, are used instead for callback functions (PNGCBAPI) and
+(PNGCAPI) for functions that must match a C library prototype (currently
+only png_longjmp_ptr, which must match the C longjmp function.)  The new
+approach is documented in pngconf.h
+
+Despite these changes, libpng 1.5.0 only supports the native C function
+calling standard on those platforms tested so far ("__cdecl" on Microsoft
+Windows).  This is because the support requirements for alternative
+calling conventions seem to no longer exist.  Developers who find it
+necessary to set PNG_API_RULE to 1 should advise the mailing list
+(png-mng-implement) of this and library builders who use Openwatcom and
+therefore set PNG_API_RULE to 2 should also contact the mailing list.
+
+B. Changes to the configuration mechanism
+
+Prior to libpng-1.5.0 library builders who needed to configure libpng
+had either to modify the exported pngconf.h header file to add system
+specific configuration or had to write feature selection macros into
+pngusr.h and cause this to be included into pngconf.h by defining
+PNG_USER_CONFIG. The latter mechanism had the disadvantage that an
+application built without PNG_USER_CONFIG defined would see the
+unmodified, default, libpng API and thus would probably fail to link.
+
+These mechanisms still work in the configure build and in any makefile
+build that builds pnglibconf.h, although the feature selection macros
+have changed somewhat as described above.  In 1.5.0, however, pngusr.h is
+processed only once, at the time the exported header file pnglibconf.h is
+built.  pngconf.h no longer includes pngusr.h; therefore, pngusr.h is ignored
+after the build of pnglibconf.h and it is never included in an application
+build.
+
+The formerly used alternative of adding a list of feature macros to the
+CPPFLAGS setting in the build also still works; however, the macros will be
+copied to pnglibconf.h and this may produce macro redefinition warnings
+when the individual C files are compiled.
+
+All configuration now only works if pnglibconf.h is built from
+scripts/pnglibconf.dfa.  This requires the program awk.  Brian Kernighan
+(the original author of awk) maintains C source code of that awk and this
+and all known later implementations (often called by subtly different
+names - nawk and gawk for example) are adequate to build pnglibconf.h.
+The Sun Microsystems (now Oracle) program 'awk' is an earlier version
+and does not work; this may also apply to other systems that have a
+functioning awk called 'nawk'.
+
+Configuration options are now documented in scripts/pnglibconf.dfa.  This
+file also includes dependency information that ensures a configuration is
+consistent; that is, if a feature is switched off, dependent features are
+also switched off.  As a recommended alternative to using feature macros in
+pngusr.h a system builder may also define equivalent options in pngusr.dfa
+(or, indeed, any file) and add that to the configuration by setting
+DFA_XTRA to the file name.  The makefiles in contrib/pngminim illustrate
+how to do this, and also illustrate a case where pngusr.h is still required.
+
+After you have built libpng, the definitions that were recorded in
+pnglibconf.h are available to your application (pnglibconf.h is included
+in png.h and gets installed alongside png.h and pngconf.h in your
+$PREFIX/include directory).  Do not edit pnglibconf.h after you have built
+libpng, because than the settings would not accurately reflect the settings
+that were used to build libpng.
+
+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
+any platform where it is guaranteed to be thread-safe.  Therefore, if
+your application is going to be using multiple threads, you should
+configure libpng with PNG_NO_SETJMP in your pngusr.dfa file, with
+-DPNG_NO_SETJMP on your compile line, or with
+
+    #undef PNG_SETJMP_SUPPORTED
+
+in your pnglibconf.h or pngusr.h.
+
+Starting with libpng-1.6.0, the library included a "simplified API".
+This requires setjmp/longjmp, so you must either build the library
+with PNG_SETJMP_SUPPORTED defined, or with PNG_SIMPLIFIED_READ_SUPPORTED
+and PNG_SIMPLIFIED_WRITE_SUPPORTED undefined.
+
+XV. Common linking failures
+
+If your application fails to find libpng or zlib entries while linking:
+
+  Be sure "-lz" appears after "-lpng" on your linking command.
+
+  Be sure you have built libpng, zlib, and your application for the
+  same platform (e.g., 32-bit or 64-bit).
+
+  If you are using the vstudio project, observe the WARNING in
+  project/vstudio/README.txt.
+
+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.
 
-Using the ./configure script -- 16 December 2002.
+Copyright (c) 2022 Cosmin Truta
-=================================================
+Copyright (c) 1998-2002,2006-2016 Glenn Randers-Pehrson
-
+This document is released under the libpng license.
-The ./configure script should work compatibly with what scripts/makefile.*
+For conditions of distribution and use, see the disclaimer
-did, however there are some options you might need to add to configure
+and license in png.h.
-explicitly, which previously was done semi-automatically (if you didn't edit
-scripts/makefile.* yourself, that is)
-
-CFLAGS="-Wall -O -funroll-loops \
--malign-loops=2 -malign-functions=2" ./configure --prefix=/usr/include \
---with-pkgconfigdir=/usr/lib/pkgconfig --includedir=/usr/include
-
-You can alternatively specify --includedir=/usr/include, /usr/local/include,
-/usr/include/libpng%NN%, or whatever.
-
-If you find that the configure script is out-of-date or is not supporting
-your platform properly, try running autogen.sh to regenerate "configure",
-"Makefile.in", and the other configuration files. Then try configure again.
-

LICENSE

@@ -1,111 +1,134 @@
+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 1.2.6, August 15, 2004, through 1.6.10, March 6, 2014, are
+ 1. The origin of this software must not be misrepresented; you
-Copyright (c) 2004, 2006-2014 Glenn Randers-Pehrson, and are
+    must not claim that you wrote the original software.  If you
-distributed according to the same disclaimer and license as libpng-1.2.5
+    use this software in a product, an acknowledgment in the product
-with the following individual added to the list of Contributing Authors
+    documentation would be appreciated, but is not required.
 
-   Cosmin Truta
+ 2. Altered source versions must be plainly marked as such, and must
+    not be misrepresented as being the original software.
 
-libpng versions 1.0.7, July 1, 2000, through 1.2.5 - October 3, 2002, are
+ 3. This Copyright notice may not be removed or altered from any
-Copyright (c) 2000-2002 Glenn Randers-Pehrson, and are
+    source or altered source distribution.
-distributed according to the same disclaimer and license as libpng-1.0.6
-with the following individuals added to the list of Contributing Authors
 
-   Simon-Pierre Cadieux
+
-   Eric S. Raymond
+PNG Reference Library License version 1 (for libpng 0.5 through 1.6.35)
-   Gilles Vollant
+-----------------------------------------------------------------------
+
+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:
+
+    Simon-Pierre Cadieux
+    Eric S. Raymond
+    Mans Rullgard
+    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
+    efforts or the library will fulfill any of your particular purposes
-   or needs.  This library is provided with all faults, and the entire
+    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
+are released under other open source licenses.
 
 libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
-Copyright (c) 1998, 1999 Glenn Randers-Pehrson, and are
+Copyright (c) 1998-2000 Glenn Randers-Pehrson, are derived from
-distributed according to the same disclaimer and license as libpng-0.96,
+libpng-0.96, and are distributed according to the same disclaimer and
-with the following individuals added to the list of Contributing Authors:
+license as libpng-0.96, with the following individuals added to the
+list of Contributing Authors:
 
-   Tom Lane
+    Tom Lane
-   Glenn Randers-Pehrson
+    Glenn Randers-Pehrson
-   Willem van Schaik
+    Willem van Schaik
 
 libpng versions 0.89, June 1996, through 0.96, May 1997, are
-Copyright (c) 1996, 1997 Andreas Dilger
+Copyright (c) 1996-1997 Andreas Dilger, are derived from libpng-0.88,
-Distributed according to the same disclaimer and license as libpng-0.88,
+and are distributed according to the same disclaimer and license as
-with the following individuals added to the list of Contributing Authors:
+libpng-0.88, with the following individuals added to the list of
+Contributing Authors:
 
-   John Bowler
+    John Bowler
-   Kevin Bracey
+    Kevin Bracey
-   Sam Bushell
+    Sam Bushell
-   Magnus Holmgren
+    Magnus Holmgren
-   Greg Roelofs
+    Greg Roelofs
-   Tom Tanner
+    Tom Tanner
+
+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
-Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
+Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
 
 For the purposes of this copyright and license, "Contributing Authors"
 is defined as the following set of individuals:
 
-   Andreas Dilger
+    Andreas Dilger
-   Dave Martindale
+    Dave Martindale
-   Guy Eric Schalnat
+    Guy Eric Schalnat
-   Paul Schmidt
+    Paul Schmidt
-   Tim Wegner
+    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
 to the following restrictions:
 
-1. The origin of this source code must not be misrepresented.
+ 1. The origin of this source code must not be misrepresented.
 
-2. Altered versions must be plainly marked as such and must not
+ 2. Altered versions must be plainly marked as such and must not
-   be misrepresented as being the original source.
+    be misrepresented as being the original source.
 
-3. This Copyright notice may not be removed or altered from any
+ 3. This Copyright notice may not be removed or altered from any
-   source or altered source distribution.
+    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.
-
-
-A "png_get_copyright" function is available, for convenient use in "about"
-boxes and the like:
-
-   printf("%s",png_get_copyright(NULL));
-
-Also, the PNG logo (in PNG format, of course) is supplied in the
-files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).
-
-Libpng is OSI Certified Open Source Software.  OSI Certified Open Source is a
-certification mark of the Open Source Initiative.
-
-Glenn Randers-Pehrson
-glennrp at users.sourceforge.net
-March 6, 2014

Makefile.am

@@ -1,16 +1,32 @@
-# Makefile.am:
+# Makefile.am, the source file for Makefile.in (and hence Makefile), is
-#   Source file for Makefile.in (and hence Makefile)
 #
+# Copyright (c) 2018-2024 Cosmin Truta
+# Copyright (c) 2004-2016 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
 
 PNGLIB_BASENAME= libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@
 
-ACLOCAL_AMFLAGS = -I scripts
+ACLOCAL_AMFLAGS = -I scripts/autoconf
 
 # test programs - run on make check, make distcheck
-check_PROGRAMS= pngtest pngunknown pngstest pngvalid pngimage
+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,
@@ -22,6 +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
 
@@ -37,36 +54,41 @@ pngunknown_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
 pngimage_SOURCES = contrib/libtests/pngimage.c
 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
 
 # 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\
    tests/pngvalid-gamma-expand16-transform tests/pngvalid-gamma-sbit\
    tests/pngvalid-gamma-threshold tests/pngvalid-gamma-transform\
-   tests/pngvalid-progressive-interlace-size\
+   tests/pngvalid-progressive-size\
    tests/pngvalid-progressive-interlace-standard\
-   tests/pngvalid-progressive-interlace-transform\
+   tests/pngvalid-transform\
    tests/pngvalid-progressive-standard tests/pngvalid-standard\
-   tests/pngstest-0g01 tests/pngstest-0g02 tests/pngstest-0g04\
+   tests/pngstest-1.8 tests/pngstest-1.8-alpha tests/pngstest-linear\
-   tests/pngstest-0g08 tests/pngstest-0g16 tests/pngstest-2c08\
+   tests/pngstest-linear-alpha tests/pngstest-none tests/pngstest-none-alpha\
-   tests/pngstest-2c16 tests/pngstest-3p01 tests/pngstest-3p02\
+   tests/pngstest-sRGB tests/pngstest-sRGB-alpha tests/pngunknown-IDAT\
-   tests/pngstest-3p04 tests/pngstest-3p08 tests/pngstest-4a08\
-   tests/pngstest-4a16 tests/pngstest-6a08 tests/pngstest-6a16\
-   tests/pngstest-error tests/pngunknown-IDAT\
    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
-# These tests are expected, and required, to fail:
-XFAIL_TESTS = tests/pngstest-error
 
 # man pages
 dist_man_MANS= libpng.3 libpngpf.3 png.5
@@ -86,7 +108,39 @@ 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
+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
@@ -109,6 +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
@@ -123,17 +181,18 @@ 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
 
-SCRIPT_CLEANFILES=scripts/*.out scripts/*.chk scripts/pnglibconf.dfn
+SCRIPT_CLEANFILES=scripts/*.out scripts/*.chk
 
 CLEANFILES= *.tf? pngout.png libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.pc \
 	libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config libpng.vers libpng.sym \
-	check.new pnglibconf.* pngprefix.h symbols.new pngtest-log.txt \
+	check.new pnglibconf.h pngprefix.h symbols.new pngtest-log.txt \
+	pnglibconf.out pnglibconf.c pnglibconf.pre pnglibconf.dfn \
 	$(SCRIPT_CLEANFILES)
 
 MAINTAINERCLEANFILES = Makefile.in aclocal.m4 config.guess config.h.in \
@@ -152,7 +211,7 @@ AM_CFLAGS = ${PNG_COPTS}
 # checks for this and sets DFNCPP appropriately.
 DFNCPP = @DFNCPP@
 
-SUFFIXES = .chk .dfn .out
+SUFFIXES = .chk .out
 
 $(PNGLIB_BASENAME).pc: libpng.pc
 	cp libpng.pc $@
@@ -224,6 +283,7 @@ contrib/libtests/timepng.o: pnglibconf.h
 
 contrib/tools/makesRGB.o: pnglibconf.h
 contrib/tools/pngfix.o: pnglibconf.h
+contrib/tools/pngcp.o: pnglibconf.h
 
 # We must use -DPNG_NO_USE_READ_MACROS here even when the library may actually
 # be built with PNG_USE_READ_MACROS; this prevents the read macros from
@@ -237,18 +297,17 @@ if DO_PNG_PREFIX
 SYMBOL_CFLAGS += -DPNG_PREFIX='@PNG_PREFIX@'
 endif
 
-.dfn.out:
+.c.out:
-	rm -f $@ $*.c $*.tf[12]
+	rm -f $@ $*.tf[12]
 	test -d scripts || mkdir scripts || test -d scripts
-	echo '#include "$<"' >$*.c
 	$(DFNCPP) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES)\
-	    $(CPPFLAGS) $(SYMBOL_CFLAGS) $*.c > $*.tf1
+	    $(CPPFLAGS) $(SYMBOL_CFLAGS) $< > $*.tf1
 	$(AWK) -f "${srcdir}/scripts/dfn.awk" out="$*.tf2" $*.tf1 1>&2
-	rm -f $*.c $*.tf1
+	rm -f $*.tf1
 	mv $*.tf2 $@
 
-# The .dfn file for pnglibconf.h is machine generated
+# The .c file for pnglibconf.h is machine generated
-pnglibconf.dfn: scripts/pnglibconf.dfa scripts/options.awk pngconf.h pngusr.dfa $(DFA_XTRA)
+pnglibconf.c: scripts/pnglibconf.dfa scripts/options.awk pngconf.h pngusr.dfa $(DFA_XTRA)
 	rm -f $@ $*.tf[45]
 	$(AWK) -f ${srcdir}/scripts/options.awk out=$*.tf4 version=search\
 	    ${srcdir}/pngconf.h ${srcdir}/scripts/pnglibconf.dfa\
@@ -268,7 +327,7 @@ scripts/symbols.chk: scripts/checksym.awk scripts/symbols.def scripts/symbols.ou
 
 # used on demand to regenerate the standard header, CPPFLAGS should
 # be empty - no non-standard defines
-scripts/pnglibconf.dfn: scripts/pnglibconf.dfa scripts/options.awk pngconf.h
+scripts/pnglibconf.c: scripts/pnglibconf.dfa scripts/options.awk pngconf.h
 	rm -f $@ pnglibconf.tf[67]
 	test -z "$(CPPFLAGS)"
 	echo "com @PNGLIB_VERSION@ STANDARD API DEFINITION" |\

README

@@ -1,49 +1,88 @@
-README for libpng version 1.6.10 - March 6, 2014 (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 do not make current programs
+It is important to note that the APIs did not make current programs
 that access the info struct directly incompatible with the new
-library.  However, it is strongly suggested that new programs use
+library, through libpng-1.2.x.  In libpng-1.4.x, which was meant to
-the new APIs (as shown in example.c and pngtest.c), and older programs
+be a transitional release, members of the `png_struct` and the
-be converted to the new format, to facilitate upgrades in the future.
+`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
-Additions since 0.90 include the ability to compile libpng as a
+reside in private `pngstruct.h` and `pnginfo.h` header files that are
-Windows DLL, and new APIs for accessing data in the info struct.
+not accessible to applications.  It is strongly suggested that new
-Experimental functions include the ability to set weighting and cost
+programs use the new APIs (as shown in `example.c` and `pngtest.c`),
-factors for row filter selection, direct reads of integers from buffers
+and older programs be converted to the new format, to facilitate
-on big-endian processors that support misaligned data access, faster
+upgrades in the future.
-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
@@ -53,150 +92,91 @@ 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
+    ANNOUNCE      =>  Announcement of this version, with recent changes
-compiler specific ones, but you may have to modify one for your own needs.
+    AUTHORS       =>  List of contributing authors
+    CHANGES       =>  Description of changes between libpng versions
+    INSTALL       =>  Instructions to install libpng
+    LICENSE       =>  License to use and redistribute libpng
+    README        =>  This file
+    TODO          =>  Things not implemented in the current library
+    TRADEMARK     =>  Trademark information
+    example.c     =>  Example code for using libpng functions
+    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 (deprecated)
+    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)
+    pngconf.h     =>  System specific library configuration (public)
+    pngstruct.h   =>  png_struct declaration (private)
+    pnginfo.h     =>  png_info struct declaration (private)
+    pngdebug.h    =>  debugging macros (private)
+    pngerror.c    =>  Error/warning message I/O functions
+    pngget.c      =>  Functions for retrieving info from struct
+    pngmem.c      =>  Memory handling functions
+    pngbar.png    =>  PNG logo, 88x31
+    pngnow.png    =>  PNG logo, 98x31
+    pngpread.c    =>  Progressive reading functions
+    pngread.c     =>  Read data/helper high-level functions
+    pngrio.c      =>  Lowest-level data read I/O functions
+    pngrtran.c    =>  Read data transformation functions
+    pngrutil.c    =>  Read data utility functions
+    pngset.c      =>  Functions for storing data into the info_struct
+    pngtest.c     =>  Library test program
+    pngtest.png   =>  Library test sample image
+    pngtrans.c    =>  Common data transformation functions
+    pngwio.c      =>  Lowest-level write I/O functions
+    pngwrite.c    =>  High-level write functions
+    pngwtran.c    =>  Write data transformations
+    pngwutil.c    =>  Write utility functions
+    arm/          =>  Optimized code for the ARM platform
+    intel/        =>  Optimized code for the INTEL-SSE2 platform
+    mips/         =>  Optimized code for the MIPS platform
+    powerpc/      =>  Optimized code for the PowerPC platform
+    ci/           =>  Scripts for continuous integration
+    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
+        libtests/     =>  Test programs
+        oss-fuzz/     =>  Files used by the OSS-Fuzz project for fuzz-testing
+                          libpng
+        pngminim/     =>  Minimal decoder, encoder, and progressive decoder
+                          programs demonstrating the use of pngusr.dfa
+        pngminus/     =>  Simple pnm2png and png2pnm programs
+        pngsuite/     =>  Test images
+        testpngs/     =>  Test images
+        tools/        =>  Various tools
+        visupng/      =>  VisualPng, a Windows viewer for PNG images
+    projects/     =>  Project files and workspaces for various IDEs
+        owatcom/      =>  OpenWatcom project
+        visualc71/    =>  Microsoft Visual C++ 7.1 workspace
+        vstudio/      =>  Microsoft Visual Studio workspace
+    scripts/      =>  Scripts and makefiles for building libpng
+                      (see scripts/README.txt for the complete list)
+    tests/        =>  Test scripts
 
-You should use zlib 1.0.4 or later to run this, but it MAY work with
+Good luck, and happy coding!
-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.
+ * Cosmin Truta (current maintainer, since 2018)
-
+ * Glenn Randers-Pehrson (former maintainer, 1998-2018)
-You may also want a copy of the PNG specification.  It is available
+ * Andreas Eric Dilger (former maintainer, 1996-1997)
-as an RFC, a W3C Recommendation, and an ISO/IEC Standard.  You can find
+ * Guy Eric Schalnat (original author and former maintainer, 1995-1996)
-these at http://www.libpng.org/pub/png/documents/
+   (formerly of Group 42, Inc.)
-
-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.
-
-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 nineteen 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
-      CHANGES       =>  Description of changes between libpng versions
-      KNOWNBUG      =>  List of known bugs and deficiencies
-      LICENSE       =>  License to use and redistribute libpng
-      README        =>  This file
-      TODO          =>  Things not implemented in the current library
-      Y2KINFO       =>  Statement of Y2K compliance
-      example.c     =>  Example code for using libpng functions
-      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
-      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)
-      pngconf.h     =>  System specific library configuration (public)
-      pngstruct.h   =>  png_struct declaration (private)
-      pnginfo.h     =>  png_info struct declaration (private)
-      pngdebug.h    =>  debugging macros (private)
-      pngerror.c    =>  Error/warning message I/O functions
-      pngget.c      =>  Functions for retrieving info from struct
-      pngmem.c      =>  Memory handling functions
-      pngbar.png    =>  PNG logo, 88x31
-      pngnow.png    =>  PNG logo, 98x31
-      pngpread.c    =>  Progressive reading functions
-      pngread.c     =>  Read data/helper high-level functions
-      pngrio.c      =>  Lowest-level data read I/O functions
-      pngrtran.c    =>  Read data transformation functions
-      pngrutil.c    =>  Read data utility functions
-      pngset.c      =>  Functions for storing data into the info_struct
-      pngtest.c     =>  Library test program
-      pngtest.png   =>  Library test sample image
-      pngtrans.c    =>  Common data transformation functions
-      pngwio.c      =>  Lowest-level write I/O functions
-      pngwrite.c    =>  High-level write functions
-      pngwtran.c    =>  Write data transformations
-      pngwutil.c    =>  Write utility functions
-      arm           =>  Contains optimized code for the ARM platform
-      contrib       =>  Contributions
-       examples         =>  Example programs
-       gregbook         =>  source code for PNG reading and writing, from
-                            Greg Roelofs' "PNG: The Definitive Guide",
-                            O'Reilly, 1999
-       libtests         =>  Test programs
-       pngminim         =>  Minimal decoder, encoder, and progressive decoder
-                            programs demonstrating use of pngusr.dfa
-       pngminus         =>  Simple pnm2png and png2pnm programs
-       pngsuite         =>  Test images
-       tools            =>  Various tools
-       visupng      =>  Contains a MSVC workspace for VisualPng
-      projects      =>  Contains project files and workspaces for
-                        building a DLL
-       owatcom          =>  Contains a WATCOM project for building libpng
-       visualc71        =>  Contains a Microsoft Visual C++ (MSVC)
-                            workspace for building libpng and zlib
-       vstudio          =>  Contains a Microsoft Visual C++ (MSVC)
-                            workspace for building libpng and zlib
-      scripts       =>  Directory containing scripts for building libpng:
-                            (see scripts/README.txt for the list of scripts)
-
-Good luck, and happy coding.
-
--Glenn Randers-Pehrson (current maintainer, since 1998)
- Internet: glennrp at users.sourceforge.net
-
--Andreas Eric Dilger (former maintainer, 1996-1997)
- Internet: adilger at enel.ucalgary.ca
- 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

@@ -1,28 +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.
+* Palette creation.
-Add "grayscale->palette" transformation and "palette->grayscale" detection.
+* "grayscale->palette" transformation and "palette->grayscale" detection.
-Improved dithering.
+* Improved dithering.
-Multi-lingual error and warning message support.
+* Multi-lingual error and warning message support.
-Complete sRGB transformation (presently it simply uses gamma=0.45455).
+* Complete sRGB transformation.  (Currently it simply uses gamma=0.45455.)
-Make profile checking optional via a png_set_something() call.
+* Man pages for function calls.
-Man pages for function calls.
+* Better documentation.
-Better documentation.
+* Better filter selection
-Better filter selection
+  (e.g., counting huffman bits/precompression; filter inertia; filter costs).
-   (counting huffman bits/precompression?  filter inertia?  filter costs?).
+* Histogram creation.
-Histogram creation.
+* Text conversion between different code pages (e.g., Latin-1 -> Mac).
-Text conversion between different code pages (Latin-1 -> Mac and DOS).
+* Avoid building gamma tables whenever possible.
-Avoid building gamma tables whenever possible.
+* Greater precision in changing to linear gamma for compositing against
-Use greater precision when changing to linear gamma for compositing against
+  background, and in doing rgb-to-gray transformations.
-  background and doing rgb-to-gray transformation.
+* Investigate pre-incremented loop counters and other loop constructions.
-Investigate pre-incremented loop counters and other loop constructions.
+* Interpolated method of handling interlacing.
-Add interpolated method of handling interlacing.
+* More validations for libpng transformations.
-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

@@ -1,28 +1,28 @@
 
 /* arm_init.c - NEON optimised filter functions
  *
- * Copyright (c) 2014 Glenn Randers-Pehrson
+ * Copyright (c) 2018-2022 Cosmin Truta
+ * Copyright (c) 2014,2016 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
  * 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"
 
 #ifdef PNG_READ_SUPPORTED
+
 #if PNG_ARM_NEON_OPT > 0
 #ifdef PNG_ARM_NEON_CHECK_SUPPORTED /* Do run-time checks */
 /* WARNING: it is strongly recommended that you do not build libpng with
  * run-time checks for CPU features if at all possible.  In the case of the ARM
  * NEON instructions there is no processor-specific way of detecting the
- * presense of the required support, therefore run-time detectioon is extremely
+ * presence of the required support, therefore run-time detection is extremely
  * OS specific.
  *
  * You may set the macro PNG_ARM_NEON_FILE to the file name of file containing
@@ -31,21 +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)
-#     define PNG_ARM_NEON_FILE "contrib/arm-neon/linux.c"
+     /* 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
@@ -65,6 +70,7 @@ png_init_filter_functions_neon(png_structp pp, unsigned int bpp)
     * wrong order of the 'ON' and 'default' cases.  UNSET now defaults to OFF,
     * as documented in png.h
     */
+   png_debug(1, "in png_init_filter_functions_neon");
 #ifdef PNG_ARM_NEON_API_SUPPORTED
    switch ((pp->options >> PNG_ARM_NEON) & 3)
    {
@@ -130,4 +136,4 @@ png_init_filter_functions_neon(png_structp pp, unsigned int bpp)
    }
 }
 #endif /* PNG_ARM_NEON_OPT > 0 */
-#endif /* PNG_READ_SUPPORTED */
+#endif /* READ */

arm/filter_neon.S

@@ -1,26 +1,27 @@
 
 /* filter_neon.S - NEON optimised filter functions
  *
- * Copyright (c) 2013 Glenn Randers-Pehrson
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 2014,2017 Glenn Randers-Pehrson
  * Written by Mans Rullgard, 2011.
- * Last changed in libpng 1.6.8 [December 19, 2013]
  *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
  * and license in png.h
  */
 
-/* This is required to get the symbol renames, which are #defines, and also
+/* This is required to get the symbol renames, which are #defines, and the
- * includes the definition (or not) of PNG_ARM_NEON_OPT and
+ * definitions (or not) of PNG_ARM_NEON_OPT and PNG_ARM_NEON_IMPLEMENTATION.
- * PNG_ARM_NEON_IMPLEMENTATION.
  */
 #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
 
+#ifdef PNG_READ_SUPPORTED
+
 /* Assembler NEON support - only works for 32-bit ARM (i.e. it does not work for
  * ARM64).  The code in arm/filter_neon_intrinsics.c supports ARM64, however it
  * only works if -mfpu=neon is specified on the GCC command line.  See pngpriv.h
@@ -28,7 +29,6 @@
  */
 #if PNG_ARM_NEON_IMPLEMENTATION == 2 /* hand-coded assembler */
 
-#ifdef PNG_READ_SUPPORTED
 #if PNG_ARM_NEON_OPT > 0
 
 #ifdef __ELF__
@@ -47,6 +47,13 @@ ELF     .size   \name, . - \name
         .purgem endfunc
     .endm
         .text
+
+        /* Explicitly specifying alignment here because some versions of
+         * GAS don't align code correctly.  This is harmless in correctly
+         * written versions of GAS.
+         */
+        .align 2
+
     .if \export
         .global \name
     .endif
@@ -242,5 +249,5 @@ func    png_read_filter_row_paeth3_neon, export=1
         pop             {r4,pc}
 endfunc
 #endif /* PNG_ARM_NEON_OPT > 0 */
-#endif /* PNG_READ_SUPPORTED */
 #endif /* PNG_ARM_NEON_IMPLEMENTATION == 2 (assembler) */
+#endif /* READ */

arm/filter_neon_intrinsics.c

@@ -1,12 +1,11 @@
 
 /* filter_neon_intrinsics.c - NEON optimised filter functions
  *
- * Copyright (c) 2013 Glenn Randers-Pehrson
+ * 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 1.6.8 [December 19, 2013]
- *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
  * and license in png.h
@@ -14,10 +13,16 @@
 
 #include "../pngpriv.h"
 
+#ifdef PNG_READ_SUPPORTED
+
 /* This code requires -mfpu=neon on the command line: */
 #if PNG_ARM_NEON_IMPLEMENTATION == 1 /* intrinsics code from pngpriv.h */
 
-#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
@@ -31,11 +36,15 @@
  * '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)
 
-#ifdef PNG_READ_SUPPORTED
 #if PNG_ARM_NEON_OPT > 0
 
 void
@@ -46,6 +55,8 @@ png_read_filter_row_up_neon(png_row_infop row_info, png_bytep row,
    png_bytep rp_stop = row + row_info->rowbytes;
    png_const_bytep pp = prev_row;
 
+   png_debug(1, "in png_read_filter_row_up_neon");
+
    for (; rp < rp_stop; rp += 16, pp += 16)
    {
       uint8x16_t qrp, qpp;
@@ -71,6 +82,8 @@ png_read_filter_row_sub3_neon(png_row_infop row_info, png_bytep row,
    uint8x8x4_t vdest;
    vdest.val[3] = vdup_n_u8(0);
 
+   png_debug(1, "in png_read_filter_row_sub3_neon");
+
    for (; rp < rp_stop;)
    {
       uint8x8_t vtmp1, vtmp2;
@@ -112,18 +125,23 @@ png_read_filter_row_sub4_neon(png_row_infop row_info, png_bytep row,
    uint8x8x4_t vdest;
    vdest.val[3] = vdup_n_u8(0);
 
+   png_debug(1, "in png_read_filter_row_sub4_neon");
+
    for (; rp < rp_stop; rp += 16)
    {
       uint32x2x4_t vtmp = vld4_u32(png_ptr(uint32_t,rp));
       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)
@@ -147,6 +165,8 @@ png_read_filter_row_avg3_neon(png_row_infop row_info, png_bytep row,
    vrpt = png_ptr(uint8x8x2_t,&vtmp);
    vrp = *vrpt;
 
+   png_debug(1, "in png_read_filter_row_avg3_neon");
+
    for (; rp < rp_stop; pp += 12)
    {
       uint8x8_t vtmp1, vtmp2, vtmp3;
@@ -206,12 +226,15 @@ png_read_filter_row_avg4_neon(png_row_infop row_info, png_bytep row,
    uint8x8x4_t vdest;
    vdest.val[3] = vdup_n_u8(0);
 
+   png_debug(1, "in png_read_filter_row_avg4_neon");
+
    for (; rp < rp_stop; rp += 16, pp += 16)
    {
       uint32x2x4_t vtmp;
       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);
@@ -229,7 +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);
    }
 }
 
@@ -279,6 +303,8 @@ png_read_filter_row_paeth3_neon(png_row_infop row_info, png_bytep row,
    vrpt = png_ptr(uint8x8x2_t,&vtmp);
    vrp = *vrpt;
 
+   png_debug(1, "in png_read_filter_row_paeth3_neon");
+
    for (; rp < rp_stop; pp += 12)
    {
       uint8x8x2_t *vppt;
@@ -338,12 +364,15 @@ png_read_filter_row_paeth4_neon(png_row_infop row_info, png_bytep row,
    uint8x8x4_t vdest;
    vdest.val[3] = vdup_n_u8(0);
 
+   png_debug(1, "in png_read_filter_row_paeth4_neon");
+
    for (; rp < rp_stop; rp += 16, pp += 16)
    {
       uint32x2x4_t vtmp;
       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);
@@ -363,10 +392,11 @@ 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);
    }
 }
 
 #endif /* PNG_ARM_NEON_OPT > 0 */
-#endif /* PNG_READ_SUPPORTED */
 #endif /* PNG_ARM_NEON_IMPLEMENTATION == 1 (intrinsics) */
+#endif /* READ */

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

@@ -73,16 +73,18 @@ done
 # present bad things are happening.
 #
 # The autotools generated files:
-libpng_autotools_files="Makefile.in aclocal.m4 config.guess config.h.in\
+libpng_autotools_files="Makefile.in aclocal.m4 config.guess config.h.in
-   config.sub configure depcomp install-sh ltmain.sh missing test-driver"
+   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"
+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
 #
@@ -193,7 +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

@@ -1,5 +1,12 @@
 # configure.ac
 
+# Copyright (c) 2018-2024 Cosmin Truta
+# Copyright (c) 2004-2016 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
+
 dnl Process this file with autoconf to produce a configure script.
 dnl
 dnl Minor upgrades (compatible ABI): increment the package version
@@ -18,8 +25,8 @@ AC_PREREQ([2.68])
 
 dnl Version number stuff here:
 
-AC_INIT([libpng],[1.6.10],[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
@@ -29,7 +36,7 @@ AC_CONFIG_MACRO_DIR([scripts])
 # 1.13 is required for parallel tests
 AM_INIT_AUTOMAKE([1.13 foreign dist-xz color-tests silent-rules subdir-objects])
 # The following line causes --disable-maintainer-mode to be the default to
-# configure, this is necessary because libpng distributions cannot rely on the
+# configure. This is necessary because libpng distributions cannot rely on the
 # time stamps of the autotools generated files being correct
 AM_MAINTAINER_MODE
 
@@ -39,10 +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=1.6.10
+PNGLIB_VERSION=1.6.41
 PNGLIB_MAJOR=1
 PNGLIB_MINOR=6
-PNGLIB_RELEASE=10
+PNGLIB_RELEASE=41
 
 dnl End of version number stuff
 
@@ -60,7 +67,7 @@ AC_PROG_INSTALL
 AC_PROG_LN_S
 AC_PROG_MAKE_SET
 
-dnl libtool/libtoolize; version 2.4.2 is the tested version, this or any
+dnl libtool/libtoolize; version 2.4.2 is the tested version. This or any
 dnl compatible later version may be used
 LT_INIT([win32-dll])
 LT_PREREQ([2.4.2])
@@ -82,9 +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])
@@ -107,26 +132,46 @@ AC_ARG_ENABLE(werror,
       CFLAGS="$sav_CFLAGS"
     fi],)
 
-# Checks for header files.
+# For GCC 5 the default mode for C is -std=gnu11 instead of -std=gnu89.
-AC_HEADER_STDC
+# In pngpriv.h we request just the POSIX 1003.1 and C89 APIs by defining
+# _POSIX_SOURCE to 1. This is incompatible with the new default mode, so
+# 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([
+      [#define _POSIX_SOURCE 1]
+      [#include <stdio.h>]
+   ])],
+   AC_MSG_RESULT(no),[
+      if test "x$GCC" != "xyes"; then
+         AC_MSG_ERROR(
+            [Forcing back to C89 is required but the flags are only known for GCC])
+      fi
+   AC_MSG_RESULT(yes)
+   CFLAGS="$CFLAGS -std=c89"
+])
 
-# Checks for typedefs, structures, and compiler characteristics.
+# Checks for 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 is soft (the corresponding test program is not built).
+AC_CHECK_FUNC([clock_gettime], , [AC_MSG_WARN([not building timepng])])
+AM_CONDITIONAL([HAVE_CLOCK_GETTIME], [test "$ac_cv_func_clock_gettime" = "yes"])
+
 AC_ARG_WITH(zlib-prefix,
    AS_HELP_STRING([[[--with-zlib-prefix]]],
       [prefix that may have been used in installed zlib]),
       [ZPREFIX=${withval}],
       [ZPREFIX='z_'])
-AC_CHECK_LIB(z, zlibVersion, ,
+AC_CHECK_LIB([z], [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
@@ -265,9 +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
 # ===
 #
@@ -286,7 +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]);;
@@ -303,15 +411,250 @@ 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*) :;;
+      arm*|aarch64*) : ;;
-      *)    test "$enable_arm_neon" != '';;
+      *)    test "$enable_arm_neon" != '' ;;
+    esac])
+
+# MIPS
+# ====
+#
+# MIPS MSA (SIMD) support.
+
+AC_ARG_ENABLE([mips-msa],
+   AS_HELP_STRING([[[--enable-mips-msa]]],
+      [Enable MIPS MSA 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 "$enableval" in
+      no|off)
+         # disable the default enabling on __mips_msa systems:
+         AC_DEFINE([PNG_MIPS_MSA_OPT], [0],
+                   [Disable MIPS MSA optimizations])
+         # Prevent inclusion of the assembler files below:
+         enable_mips_msa=no ;;
+      check)
+         AC_DEFINE([PNG_MIPS_MSA_CHECK_SUPPORTED], [],
+                   [Check for MIPS MSA support at run-time]);;
+      api)
+         AC_DEFINE([PNG_MIPS_MSA_API_SUPPORTED], [],
+                   [Turn on MIPS MSA optimizations at run-time]);;
+      yes|on)
+         AC_DEFINE([PNG_MIPS_MSA_OPT], [2],
+                   [Enable MIPS MSA optimizations])
+         AC_MSG_WARN([--enable-mips-msa: please specify 'check' or 'api', if]
+            [you want the optimizations unconditionally pass '-mmsa -mfp64']
+            [to the compiler.]);;
+      *)
+         AC_MSG_ERROR([--enable-mips-msa=${enable_mips_msa}: invalid value])
+   esac])
+
+# Add MIPS-specific files to all builds where $host_cpu is mips ('mips*') or
+# where MIPS optimizations were explicitly requested (this allows a fallback
+# if a future host CPU does not match 'mips*')
+
+AM_CONDITIONAL([PNG_MIPS_MSA],
+   [test "$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]])

contrib/README.txt

@@ -1,4 +1,5 @@
 
 This "contrib" directory contains contributions which are not necessarily under
 the libpng license, although all are open source.  They are not part of
-libpng proper and are not used for building the library.
+libpng proper and are not used for building the library, although some are used
+for testing the library via "make check".

contrib/arm-neon/README

@@ -1,7 +1,7 @@
 OPERATING SYSTEM SPECIFIC ARM NEON DETECTION
 --------------------------------------------
 
-Detection of the ability to exexcute ARM NEON on an ARM processor requires
+Detection of the ability to execute ARM NEON on an ARM processor requires
 operating system support.  (The information is not available in user mode.)
 
 HOW TO USE THIS

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

@@ -2,12 +2,11 @@
  *
  * 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
  * and license in png.h
- * 
+ *
  * SEE contrib/arm-neon/README before reporting bugs
  *
  * STATUS: COMPILED, TESTED
@@ -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 1.6.10 [March 6, 2014]
  *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
@@ -16,9 +15,10 @@
  * png_have_neon implemented for Linux by reading the widely available
  * pseudo-file /proc/cpuinfo.
  *
- * This code is strict ANSI-C and is probably moderately portable, it does
+ * This code is strict ANSI-C and is probably moderately portable; it does
- * however use <stdio.h> and assumes that /proc/cpuinfo is never localized.
+ * 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. */
@@ -72,10 +72,10 @@ png_have_neon(png_structp png_ptr)
                      state = Colon;
                   break;
                }
-               
+
                /* 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 */
@@ -152,8 +152,10 @@ png_have_neon(png_structp png_ptr)
       }
    }
 
+#ifdef PNG_WARNINGS_SUPPORTED
    else
       png_warning(png_ptr, "/proc/cpuinfo open failed");
+#endif
 
    return 0;
 }

contrib/conftest/pngcp.dfa

@@ -0,0 +1,57 @@
+# pngcp.dfa
+#  Build time configuration of libpng
+#
+# Author: John Bowler
+# Copyright: (c) John Bowler, 2016
+# Usage rights:
+#  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.
+#
+# Build libpng with support for pngcp.  This means just png_read_png,
+# png_write_png and small number of configuration settings.
+#
+everything = off
+
+# This option is specific to this configuration; it adds a #define to the
+# generated pnglibconf.h which turns on the (not portable) timing option for
+# pngcp.  Note that any option is automatically preceded by PNG_; there is no
+# way round this and this is deliberate.
+option PNGCP_TIMING
+
+# Because of the everything off above the option must also be turned on.  This
+# may not be done in one step because it is safer and avoids mis-spelled options
+# in user .dfa files to error out if an unrecognized option is turned on.
+option PNGCP_TIMING on
+
+# Options to turn on png_read_png and png_write_png:
+option INFO_IMAGE on
+option SEQUENTIAL_READ on
+option EASY_ACCESS on
+option WRITE on
+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 support
+option UNKNOWN_CHUNKS on
+option SET_UNKNOWN_CHUNKS on
+option HANDLE_AS_UNKNOWN on
+option SAVE_UNKNOWN_CHUNKS on
+option WRITE_UNKNOWN_CHUNKS on
+
+# pngcp needs this to handle palette files with invalid indices:
+option CHECK_FOR_INVALID_INDEX on
+option GET_PALETTE_MAX on
+
+# Pre-libpng 1.7 pngcp has to stash text chunks manually, post 1.7 without this
+# text chunks should be handled as unknown ok.
+option TEXT on
+
+# this is used to turn off limits:
+option USER_LIMITS on
+option SET_USER_LIMITS on
+
+# these are just required for specific customizations
+option WRITE_CUSTOMIZE_ZTXT_COMPRESSION on
+option WRITE_CUSTOMIZE_COMPRESSION on

contrib/examples/README.txt

@@ -21,4 +21,4 @@ ORIGINAL AUTHORS
     of the people below claim any rights with regard to the contents of this
     directory.
 
-    John Bowler <jbowler@acm.org>
+    John Bowler <jbowler at acm.org>

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.
@@ -26,6 +26,10 @@
 
 #include <png.h>
 
+#if defined(PNG_READ_SUPPORTED) && defined(PNG_STDIO_SUPPORTED) && \
+    defined (PNG_iCCP_SUPPORTED)
+
+
 static int verbose = 1;
 static png_byte no_profile[] = "no profile";
 
@@ -178,3 +182,4 @@ main(int argc, char **argv)
    /* Exit code is true if any extract succeeds */
    return extracted == 0;
 }
+#endif /* READ && STDIO && iCCP */

contrib/examples/pngpixel.c

@@ -27,6 +27,8 @@
  */
 #include "../../png.h"
 
+#if defined(PNG_READ_SUPPORTED) && defined(PNG_SEQUENTIAL_READ_SUPPORTED)
+
 /* Return component 'c' of pixel 'x' from the given row. */
 static unsigned int
 component(png_const_bytep row, png_uint_32 x, unsigned int c,
@@ -40,7 +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;
 
@@ -71,7 +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))
    {
@@ -85,7 +87,7 @@ print_pixel(png_structp png_ptr, png_infop info_ptr, png_const_bytep row,
        */
       case PNG_COLOR_TYPE_PALETTE:
          {
-            PNG_CONST unsigned 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;
 
@@ -366,3 +368,4 @@ int main(int argc, const char **argv)
 
    return result;
 }
+#endif /* READ && SEQUENTIAL_READ */

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.
@@ -20,6 +20,8 @@
  * ensure the code picks up the local libpng implementation:
  */
 #include "../../png.h"
+#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) && \
+    defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
 
 int main(int argc, const char **argv)
 {
@@ -57,26 +59,27 @@ int main(int argc, const char **argv)
                else
                   fprintf(stderr, "pngtopng: write %s: %s\n", argv[2],
                       image.message);
-
-               free(buffer);
             }
 
             else
-            {
                fprintf(stderr, "pngtopng: read %s: %s\n", argv[1],
                    image.message);
 
-               /* This is the only place where a 'free' is required; libpng does
+            free(buffer);
-                * the cleanup on error and success, but in this case we couldn't
-                * complete the read because of running out of memory.
-                */
-               png_image_free(&image);
-            }
          }
 
          else
+         {
             fprintf(stderr, "pngtopng: out of memory: %lu bytes\n",
                (unsigned long)PNG_IMAGE_SIZE(image));
+
+            /* This is the only place where a 'free' is required; libpng does
+             * the cleanup on error and success, but in this case we couldn't
+             * complete the read because of running out of memory and so libpng
+             * has not got to the point where it can do cleanup.
+             */
+            png_image_free(&image);
+         }
       }
 
       else
@@ -90,3 +93,4 @@ int main(int argc, const char **argv)
 
    return result;
 }
+#endif /* READ && WRITE */

contrib/examples/simpleover.c

@@ -0,0 +1,648 @@
+/*- simpleover
+ *
+ * COPYRIGHT: Written by John Cunningham Bowler, 2015.
+ * 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.
+ *
+ * Read several PNG files, which should have an alpha channel or transparency
+ * information, and composite them together to produce one or more 16-bit linear
+ * RGBA intermediates.  This involves doing the correct 'over' composition to
+ * combine the alpha channels and corresponding data.
+ *
+ * Finally read an output (background) PNG using the 24-bit RGB format (the
+ * PNG will be composited on green (#00ff00) by default if it has an alpha
+ * channel), and apply the intermediate image generated above to specified
+ * locations in the image.
+ *
+ * The command line has the general format:
+ *
+ *    simpleover <background.png> [output.png]
+ *        {--sprite=width,height,name {[--at=x,y] {sprite.png}}}
+ *        {--add=name {x,y}}
+ *
+ * The --sprite and --add options may occur multiple times. They are executed
+ * in order.  --add may refer to any sprite already read.
+ *
+ * This code is intended to show how to composite multiple images together
+ * correctly.  Apart from the libpng Simplified API the only work done in here
+ * is to combine multiple input PNG images into a single sprite; this involves
+ * a Porter-Duff 'over' operation and the input PNG images may, as a result,
+ * be regarded as being layered one on top of the other with the first (leftmost
+ * on the command line) being at the bottom and the last on the top.
+ */
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <errno.h>
+
+/* Normally use <png.h> here to get the installed libpng, but this is done to
+ * ensure the code picks up the local libpng implementation, so long as this
+ * file is linked against a sufficiently recent libpng (1.6+) it is ok to
+ * change this to <png.h>:
+ */
+#include "../../png.h"
+
+#ifdef PNG_SIMPLIFIED_READ_SUPPORTED
+
+#define sprite_name_chars 15
+struct sprite {
+   FILE         *file;
+   png_uint_16p  buffer;
+   unsigned int  width;
+   unsigned int  height;
+   char          name[sprite_name_chars+1];
+};
+
+#if 0 /* div by 65535 test program */
+#include <math.h>
+#include <stdio.h>
+
+int main(void) {
+   double err = 0;
+   unsigned int xerr = 0;
+   unsigned int r = 32769;
+   {
+      unsigned int x = 0;
+
+      do {
+         unsigned int t = x + (x >> 16) /*+ (x >> 31)*/ + r;
+         double v = x, errtest;
+
+         if (t < x) {
+            fprintf(stderr, "overflow: %u+%u -> %u\n", x, r, t);
+            return 1;
+         }
+
+         v /= 65535;
+         errtest = v;
+         t >>= 16;
+         errtest -= t;
+
+         if (errtest > err) {
+            err = errtest;
+            xerr = x;
+
+            if (errtest >= .5) {
+               fprintf(stderr, "error: %u/65535 = %f, not %u, error %f\n",
+                     x, v, t, errtest);
+               return 0;
+            }
+         }
+      } while (++x <= 65535U*65535U);
+   }
+
+   printf("error %f @ %u\n", err, xerr);
+
+   return 0;
+}
+#endif /* div by 65535 test program */
+
+static void
+sprite_op(const struct sprite *sprite, int x_offset, int y_offset,
+   png_imagep image, const png_uint_16 *buffer)
+{
+   /* This is where the Porter-Duff 'Over' operator is evaluated; change this
+    * code to change the operator (this could be parameterized).  Any other
+    * image processing operation could be used here.
+    */
+
+
+   /* Check for an x or y offset that pushes any part of the image beyond the
+    * right or bottom of the sprite:
+    */
+   if ((y_offset < 0 || (unsigned)/*SAFE*/y_offset < sprite->height) &&
+       (x_offset < 0 || (unsigned)/*SAFE*/x_offset < sprite->width))
+   {
+      unsigned int y = 0;
+
+      if (y_offset < 0)
+         y = -y_offset; /* Skip to first visible row */
+
+      do
+      {
+         unsigned int x = 0;
+
+         if (x_offset < 0)
+            x = -x_offset;
+
+         do
+         {
+            /* In and out are RGBA values, so: */
+            const png_uint_16 *in_pixel = buffer + (y * image->width + x)*4;
+            png_uint_32 in_alpha = in_pixel[3];
+
+            /* This is the optimized Porter-Duff 'Over' operation, when the
+             * input alpha is 0 the output is not changed.
+             */
+            if (in_alpha > 0)
+            {
+               png_uint_16 *out_pixel = sprite->buffer +
+                  ((y+y_offset) * sprite->width + (x+x_offset))*4;
+
+               /* This is the weight to apply to the output: */
+               in_alpha = 65535-in_alpha;
+
+               if (in_alpha > 0)
+               {
+                  /* The input must be composed onto the output. This means
+                   * multiplying the current output pixel value by the inverse
+                   * of the input alpha (1-alpha). A division is required but
+                   * it is by the constant 65535.  Approximate this as:
+                   *
+                   *     (x + (x >> 16) + 32769) >> 16;
+                   *
+                   * This is exact (and does not overflow) for all values of
+                   * x in the range 0..65535*65535.  (Note that the calculation
+                   * produces the closest integer; the maximum error is <0.5).
+                   */
+                  png_uint_32 tmp;
+
+#                 define compose(c)\
+                     tmp = out_pixel[c] * in_alpha;\
+                     tmp = (tmp + (tmp >> 16) + 32769) >> 16;\
+                     out_pixel[c] = tmp + in_pixel[c]
+
+                  /* The following is very vectorizable... */
+                  compose(0);
+                  compose(1);
+                  compose(2);
+                  compose(3);
+               }
+
+               else
+                  out_pixel[0] = in_pixel[0],
+                  out_pixel[1] = in_pixel[1],
+                  out_pixel[2] = in_pixel[2],
+                  out_pixel[3] = in_pixel[3];
+            }
+         }
+         while (++x < image->width);
+      }
+      while (++y < image->height);
+   }
+}
+
+static int
+create_sprite(struct sprite *sprite, int *argc, const char ***argv)
+{
+   /* Read the arguments and create this sprite. The sprite buffer has already
+    * been allocated. This reads the input PNGs one by one in linear format,
+    * composes them onto the sprite buffer (the code in the function above)
+    * then saves the result, converting it on the fly to PNG RGBA 8-bit format.
+    */
+   while (*argc > 0)
+   {
+      char tombstone;
+      int x = 0, y = 0;
+
+      if ((*argv)[0][0] == '-' && (*argv)[0][1] == '-')
+      {
+         /* The only supported option is --at. */
+         if (sscanf((*argv)[0], "--at=%d,%d%c", &x, &y, &tombstone) != 2)
+            break; /* success; caller will parse this option */
+
+         ++*argv, --*argc;
+      }
+
+      else
+      {
+         /* The argument has to be a file name */
+         png_image image;
+
+         image.version = PNG_IMAGE_VERSION;
+         image.opaque = NULL;
+
+         if (png_image_begin_read_from_file(&image, (*argv)[0]))
+         {
+            png_uint_16p buffer;
+
+            image.format = PNG_FORMAT_LINEAR_RGB_ALPHA;
+
+            buffer = malloc(PNG_IMAGE_SIZE(image));
+
+            if (buffer != NULL)
+            {
+               if (png_image_finish_read(&image, NULL/*background*/, buffer,
+                  0/*row_stride*/,
+                  NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP*/))
+               {
+                  /* This is the place where the Porter-Duff 'Over' operator
+                   * needs to be done by this code.  In fact, any image
+                   * processing required can be done here; the data is in
+                   * the correct format (linear, 16-bit) and source and
+                   * destination are in memory.
+                   */
+                  sprite_op(sprite, x, y, &image, buffer);
+                  free(buffer);
+                  ++*argv, --*argc;
+                  /* And continue to the next argument */
+                  continue;
+               }
+
+               else
+               {
+                  free(buffer);
+                  fprintf(stderr, "simpleover: read %s: %s\n", (*argv)[0],
+                      image.message);
+               }
+            }
+
+            else
+            {
+               fprintf(stderr, "simpleover: out of memory: %lu bytes\n",
+                  (unsigned long)PNG_IMAGE_SIZE(image));
+
+               /* png_image_free must be called if we abort the Simplified API
+                * read because of a problem detected in this code.  If problems
+                * are detected in the Simplified API it cleans up itself.
+                */
+               png_image_free(&image);
+            }
+         }
+
+         else
+         {
+            /* Failed to read the first argument: */
+            fprintf(stderr, "simpleover: %s: %s\n", (*argv)[0], image.message);
+         }
+
+         return 0; /* failure */
+      }
+   }
+
+   /* All the sprite operations have completed successfully. Save the RGBA
+    * buffer as a PNG using the simplified write API.
+    */
+   sprite->file = tmpfile();
+
+   if (sprite->file != NULL)
+   {
+      png_image save;
+
+      memset(&save, 0, sizeof save);
+      save.version = PNG_IMAGE_VERSION;
+      save.opaque = NULL;
+      save.width = sprite->width;
+      save.height = sprite->height;
+      save.format = PNG_FORMAT_LINEAR_RGB_ALPHA;
+      save.flags = PNG_IMAGE_FLAG_FAST;
+      save.colormap_entries = 0;
+
+      if (png_image_write_to_stdio(&save, sprite->file, 1/*convert_to_8_bit*/,
+          sprite->buffer, 0/*row_stride*/, NULL/*colormap*/))
+      {
+         /* Success; the buffer is no longer needed: */
+         free(sprite->buffer);
+         sprite->buffer = NULL;
+         return 1; /* ok */
+      }
+
+      else
+         fprintf(stderr, "simpleover: write sprite %s: %s\n", sprite->name,
+            save.message);
+   }
+
+   else
+      fprintf(stderr, "simpleover: sprite %s: could not allocate tmpfile: %s\n",
+         sprite->name, strerror(errno));
+
+   return 0; /* fail */
+}
+
+static int
+add_sprite(png_imagep output, png_bytep out_buf, struct sprite *sprite,
+   int *argc, const char ***argv)
+{
+   /* Given a --add argument naming this sprite, perform the operations listed
+    * in the following arguments.  The arguments are expected to have the form
+    * (x,y), which is just an offset at which to add the sprite to the
+    * output.
+    */
+   while (*argc > 0)
+   {
+      char tombstone;
+      int x, y;
+
+      if ((*argv)[0][0] == '-' && (*argv)[0][1] == '-')
+         return 1; /* success */
+
+      if (sscanf((*argv)[0], "%d,%d%c", &x, &y, &tombstone) == 2)
+      {
+         /* Now add the new image into the sprite data, but only if it
+          * will fit.
+          */
+         if (x < 0 || y < 0 ||
+             (unsigned)/*SAFE*/x >= output->width ||
+             (unsigned)/*SAFE*/y >= output->height ||
+             sprite->width > output->width-x ||
+             sprite->height > output->height-y)
+         {
+            fprintf(stderr, "simpleover: sprite %s @ (%d,%d) outside image\n",
+               sprite->name, x, y);
+            /* Could just skip this, but for the moment it is an error */
+            return 0; /* error */
+         }
+
+         else
+         {
+            /* Since we know the sprite fits we can just read it into the
+             * output using the simplified API.
+             */
+            png_image in;
+
+            in.version = PNG_IMAGE_VERSION;
+            rewind(sprite->file);
+
+            if (png_image_begin_read_from_stdio(&in, sprite->file))
+            {
+               in.format = PNG_FORMAT_RGB; /* force compose */
+
+               if (png_image_finish_read(&in, NULL/*background*/,
+                  out_buf + (y*output->width + x)*3/*RGB*/,
+                  output->width*3/*row_stride*/,
+                  NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP*/))
+               {
+                  ++*argv, --*argc;
+                  continue;
+               }
+            }
+
+            /* The read failed: */
+            fprintf(stderr, "simpleover: add sprite %s: %s\n", sprite->name,
+                in.message);
+            return 0; /* error */
+         }
+      }
+
+      else
+      {
+         fprintf(stderr, "simpleover: --add='%s': invalid position %s\n",
+               sprite->name, (*argv)[0]);
+         return 0; /* error */
+      }
+   }
+
+   return 1; /* ok */
+}
+
+static int
+simpleover_process(png_imagep output, png_bytep out_buf, int argc,
+   const char **argv)
+{
+   int result = 1; /* success */
+#  define csprites 10/*limit*/
+#  define str(a) #a
+   int nsprites = 0;
+   struct sprite sprites[csprites];
+
+   while (argc > 0)
+   {
+      result = 0; /* fail */
+
+      if (strncmp(argv[0], "--sprite=", 9) == 0)
+      {
+         char tombstone;
+
+         if (nsprites < csprites)
+         {
+            int n;
+
+            sprites[nsprites].width = sprites[nsprites].height = 0;
+            sprites[nsprites].name[0] = 0;
+
+            n = sscanf(argv[0], "--sprite=%u,%u,%" str(sprite_name_chars) "s%c",
+                &sprites[nsprites].width, &sprites[nsprites].height,
+                sprites[nsprites].name, &tombstone);
+
+            if ((n == 2 || n == 3) &&
+                sprites[nsprites].width > 0 && sprites[nsprites].height > 0)
+            {
+               size_t buf_size, tmp;
+
+               /* Default a name if not given. */
+               if (sprites[nsprites].name[0] == 0)
+                  sprintf(sprites[nsprites].name, "sprite-%d", nsprites+1);
+
+               /* Allocate a buffer for the sprite and calculate the buffer
+                * size:
+                */
+               buf_size = sizeof (png_uint_16 [4]);
+               buf_size *= sprites[nsprites].width;
+               buf_size *= sprites[nsprites].height;
+
+               /* This can overflow a (size_t); check for this: */
+               tmp = buf_size;
+               tmp /= sprites[nsprites].width;
+               tmp /= sprites[nsprites].height;
+
+               if (tmp == sizeof (png_uint_16 [4]))
+               {
+                  sprites[nsprites].buffer = malloc(buf_size);
+                  /* This buffer must be initialized to transparent: */
+                  memset(sprites[nsprites].buffer, 0, buf_size);
+
+                  if (sprites[nsprites].buffer != NULL)
+                  {
+                     sprites[nsprites].file = NULL;
+                     ++argv, --argc;
+
+                     if (create_sprite(sprites+nsprites++, &argc, &argv))
+                     {
+                        result = 1; /* still ok */
+                        continue;
+                     }
+
+                     break; /* error */
+                  }
+               }
+
+               /* Overflow, or OOM */
+               fprintf(stderr, "simpleover: %s: sprite too large\n", argv[0]);
+               break;
+            }
+
+            else
+            {
+               fprintf(stderr, "simpleover: %s: invalid sprite (%u,%u)\n",
+                  argv[0], sprites[nsprites].width, sprites[nsprites].height);
+               break;
+            }
+         }
+
+         else
+         {
+            fprintf(stderr, "simpleover: %s: too many sprites\n", argv[0]);
+            break;
+         }
+      }
+
+      else if (strncmp(argv[0], "--add=", 6) == 0)
+      {
+         const char *name = argv[0]+6;
+         int isprite = nsprites;
+
+         ++argv, --argc;
+
+         while (--isprite >= 0)
+         {
+            if (strcmp(sprites[isprite].name, name) == 0)
+            {
+               if (!add_sprite(output, out_buf, sprites+isprite, &argc, &argv))
+                  goto out; /* error in add_sprite */
+
+               break;
+            }
+         }
+
+         if (isprite < 0) /* sprite not found */
+         {
+            fprintf(stderr, "simpleover: --add='%s': sprite not found\n", name);
+            break;
+         }
+      }
+
+      else
+      {
+         fprintf(stderr, "simpleover: %s: unrecognized operation\n", argv[0]);
+         break;
+      }
+
+      result = 1; /* ok  */
+   }
+
+   /* Clean up the cache of sprites: */
+out:
+   while (--nsprites >= 0)
+   {
+      if (sprites[nsprites].buffer != NULL)
+         free(sprites[nsprites].buffer);
+
+      if (sprites[nsprites].file != NULL)
+         (void)fclose(sprites[nsprites].file);
+   }
+
+   return result;
+}
+
+int main(int argc, const char **argv)
+{
+   int result = 1; /* default to fail */
+
+   if (argc >= 2)
+   {
+      int argi = 2;
+      const char *output = NULL;
+      png_image image;
+
+      if (argc > 2 && argv[2][0] != '-'/*an operation*/)
+      {
+         output = argv[2];
+         argi = 3;
+      }
+
+      image.version = PNG_IMAGE_VERSION;
+      image.opaque = NULL;
+
+      if (png_image_begin_read_from_file(&image, argv[1]))
+      {
+         png_bytep buffer;
+
+         image.format = PNG_FORMAT_RGB; /* 24-bit RGB */
+
+         buffer = malloc(PNG_IMAGE_SIZE(image));
+
+         if (buffer != NULL)
+         {
+            png_color background = {0, 0xff, 0}; /* fully saturated green */
+
+            if (png_image_finish_read(&image, &background, buffer,
+               0/*row_stride*/, NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP */))
+            {
+               /* At this point png_image_finish_read has cleaned up the
+                * allocated data in png_image, and only the buffer needs to be
+                * freed.
+                *
+                * Perform the remaining operations:
+                */
+               if (simpleover_process(&image, buffer, argc-argi, argv+argi))
+               {
+                  /* Write the output: */
+                  if ((output != NULL &&
+                       png_image_write_to_file(&image, output,
+                        0/*convert_to_8bit*/, buffer, 0/*row_stride*/,
+                        NULL/*colormap*/)) ||
+                      (output == NULL &&
+                       png_image_write_to_stdio(&image, stdout,
+                        0/*convert_to_8bit*/, buffer, 0/*row_stride*/,
+                        NULL/*colormap*/)))
+                     result = 0;
+
+                  else
+                     fprintf(stderr, "simpleover: write %s: %s\n",
+                        output == NULL ? "stdout" : output, image.message);
+               }
+
+               /* else simpleover_process writes an error message */
+            }
+
+            else
+               fprintf(stderr, "simpleover: read %s: %s\n", argv[1],
+                   image.message);
+
+            free(buffer);
+         }
+
+         else
+         {
+            fprintf(stderr, "simpleover: out of memory: %lu bytes\n",
+               (unsigned long)PNG_IMAGE_SIZE(image));
+
+            /* This is the only place where a 'free' is required; libpng does
+             * the cleanup on error and success, but in this case we couldn't
+             * complete the read because of running out of memory.
+             */
+            png_image_free(&image);
+         }
+      }
+
+      else
+      {
+         /* Failed to read the first argument: */
+         fprintf(stderr, "simpleover: %s: %s\n", argv[1], image.message);
+      }
+   }
+
+   else
+   {
+      /* Usage message */
+      fprintf(stderr,
+         "simpleover: usage: simpleover background.png [output.png]\n"
+         "  Output 'background.png' as a 24-bit RGB PNG file in 'output.png'\n"
+         "   or, if not given, stdout.  'background.png' will be composited\n"
+         "   on fully saturated green.\n"
+         "\n"
+         "  Optionally, before output, process additional PNG files:\n"
+         "\n"
+         "   --sprite=width,height,name {[--at=x,y] {sprite.png}}\n"
+         "    Produce a transparent sprite of size (width,height) and with\n"
+         "     name 'name'.\n"
+         "    For each sprite.png composite it using a Porter-Duff 'Over'\n"
+         "     operation at offset (x,y) in the sprite (defaulting to (0,0)).\n"
+         "     Input PNGs will be truncated to the area of the sprite.\n"
+         "\n"
+         "   --add='name' {x,y}\n"
+         "    Optionally, before output, composite a sprite, 'name', which\n"
+         "     must have been previously produced using --sprite, at each\n"
+         "     offset (x,y) in the output image.  Each sprite must fit\n"
+         "     completely within the output image.\n"
+         "\n"
+         "  PNG files are processed in the order they occur on the command\n"
+         "  line and thus the first PNG processed appears as the bottommost\n"
+         "  in the output image.\n");
+   }
+
+   return result;
+}
+#endif /* SIMPLIFIED_READ */

contrib/gregbook/Makefile.unx

@@ -59,15 +59,16 @@ INCS = $(PNGINC) $(ZINC) $(XINC)
 RLIBSd = $(PNGLIBd) $(ZLIBd) $(XLIB) -lm
 RLIBSs = $(PNGLIBs) $(ZLIBs) $(XLIB) -lm
 WLIBSd = $(PNGLIBd) $(ZLIBd) -lm
-WLIBSs = $(PNGLIBs) $(ZLIBs)
+WLIBSs = $(PNGLIBs) $(ZLIBs) -lm
 
 CC = gcc
 LD = gcc
 RM = rm -f
 CPPFLAGS = $(INCS) -DFEATURE_LOOP
 CFLAGS = -O -Wall
+#CFLAGS = -O -W -Wall -Wextra -pedantic -ansi
 # [note that -Wall is a gcc-specific compilation flag ("most warnings on")]
-# [-ansi, -pedantic and -W can also be used]
+# [-ansi, -pedantic, -Wextra, and -W can also be used]
 LDFLAGS =
 O = .o
 E =

contrib/gregbook/README

@@ -15,7 +15,7 @@ of PBMPLUS/NetPBM) and converts them to PNG.
 
 The source code for all three demo programs currently compiles under
 Unix, OpenVMS, and 32-bit Windows.  (Special thanks to Martin Zinser,
-zinser@decus.de, for making the necessary changes for OpenVMS and for
+zinser at decus.de, for making the necessary changes for OpenVMS and for
 providing an appropriate build script.)  Build instructions can be found
 below.
 
@@ -55,7 +55,7 @@ mation and links to the latest version of the source code, and Chapters
 13-15 of the book for detailed discussion of the three programs.
 
 Greg Roelofs
-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
@@ -100,7 +100,8 @@ int readpng_init(FILE *infile, ulg *pWidth, ulg *pHeight)
 
     /* could pass pointers to user-defined error handlers instead of NULLs: */
 
-    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+    png_ptr = png_create_read_struct(png_get_libpng_ver(NULL), NULL, NULL,
+        NULL);
     if (!png_ptr)
         return 4;   /* out of memory */
 
@@ -263,6 +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

@@ -4,7 +4,7 @@
 
   ---------------------------------------------------------------------------
 
-      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
+      Copyright (c) 1998-2015 Greg Roelofs.  All rights reserved.
 
       This software is provided "as is," without warranty of any kind,
       express or implied.  In no event shall the author or contributors
@@ -51,6 +51,12 @@
       along with this program; if not, write to the Free Software Foundation,
       Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 
+  ---------------------------------------------------------------------------
+
+   Changelog:
+     2015-11-12 - Check return value of png_get_bKGD() (Glenn R-P)
+     2017-04-22 - Guard against integer overflow (Glenn R-P)
+
   ---------------------------------------------------------------------------*/
 
 
@@ -104,7 +110,7 @@ int readpng2_init(mainprog_info *mainprog_ptr)
 
     /* could also replace libpng warning-handler (final NULL), but no need: */
 
-    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, mainprog_ptr,
+    png_ptr = png_create_read_struct(png_get_libpng_ver(NULL), mainprog_ptr,
       readpng2_error_handler, readpng2_warning_handler);
     if (!png_ptr)
         return 4;   /* out of memory */
@@ -140,7 +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 */
@@ -261,36 +267,38 @@ static void readpng2_info_callback(png_structp png_ptr, png_infop info_ptr)
     /* since we know we've read all of the PNG file's "header" (i.e., up
      * to IDAT), we can check for a background color here */
 
-    if (mainprog_ptr->need_bgcolor &&
+    if (mainprog_ptr->need_bgcolor)
-        png_get_valid(png_ptr, info_ptr, PNG_INFO_bKGD))
     {
         png_color_16p pBackground;
 
         /* it is not obvious from the libpng documentation, but this function
          * takes a pointer to a pointer, and it always returns valid red,
          * green and blue values, regardless of color_type: */
-        png_get_bKGD(png_ptr, info_ptr, &pBackground);
+        if (png_get_bKGD(png_ptr, info_ptr, &pBackground))
+        {
 
-        /* however, it always returns the raw bKGD data, regardless of any
+           /* however, it always returns the raw bKGD data, regardless of any
-         * bit-depth transformations, so check depth and adjust if necessary */
+            * bit-depth transformations, so check depth and adjust if necessary
-        if (bit_depth == 16) {
+            */
-            mainprog_ptr->bg_red   = pBackground->red   >> 8;
+           if (bit_depth == 16) {
-            mainprog_ptr->bg_green = pBackground->green >> 8;
+               mainprog_ptr->bg_red   = pBackground->red   >> 8;
-            mainprog_ptr->bg_blue  = pBackground->blue  >> 8;
+               mainprog_ptr->bg_green = pBackground->green >> 8;
-        } else if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) {
+               mainprog_ptr->bg_blue  = pBackground->blue  >> 8;
-            if (bit_depth == 1)
+           } else if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) {
-                mainprog_ptr->bg_red = mainprog_ptr->bg_green =
+               if (bit_depth == 1)
-                  mainprog_ptr->bg_blue = pBackground->gray? 255 : 0;
+                   mainprog_ptr->bg_red = mainprog_ptr->bg_green =
-            else if (bit_depth == 2)
+                     mainprog_ptr->bg_blue = pBackground->gray? 255 : 0;
-                mainprog_ptr->bg_red = mainprog_ptr->bg_green =
+               else if (bit_depth == 2)
-                  mainprog_ptr->bg_blue = (255/3) * pBackground->gray;
+                   mainprog_ptr->bg_red = mainprog_ptr->bg_green =
-            else /* bit_depth == 4 */
+                     mainprog_ptr->bg_blue = (255/3) * pBackground->gray;
-                mainprog_ptr->bg_red = mainprog_ptr->bg_green =
+               else /* bit_depth == 4 */
-                  mainprog_ptr->bg_blue = (255/15) * pBackground->gray;
+                   mainprog_ptr->bg_red = mainprog_ptr->bg_green =
-        } else {
+                     mainprog_ptr->bg_blue = (255/15) * pBackground->gray;
-            mainprog_ptr->bg_red   = (uch)pBackground->red;
+           } else {
-            mainprog_ptr->bg_green = (uch)pBackground->green;
+               mainprog_ptr->bg_red   = (uch)pBackground->red;
-            mainprog_ptr->bg_blue  = (uch)pBackground->blue;
+               mainprog_ptr->bg_green = (uch)pBackground->green;
+               mainprog_ptr->bg_blue  = (uch)pBackground->blue;
+           }
         }
     }
 
@@ -448,6 +456,8 @@ static void readpng2_end_callback(png_structp png_ptr, png_infop info_ptr)
 
     /* all done */
 
+    (void)info_ptr; /* Unused */
+
     return;
 }
 
@@ -472,6 +482,7 @@ static void readpng2_warning_handler(png_structp png_ptr, png_const_charp msg)
 {
     fprintf(stderr, "readpng2 libpng warning: %s\n", msg);
     fflush(stderr);
+    (void)png_ptr; /* Unused */
 }
 
 

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
@@ -154,17 +154,26 @@ uch *readpng_get_image(double display_exponent, int *pChannels, ulg *pRowbytes)
     *pRowbytes = rowbytes = channels*width;
     *pChannels = channels;
 
+    Trace((stderr, "readpng_get_image:  rowbytes = %ld, height = %ld\n", rowbytes, height));
+
+    /* Guard against integer overflow */
+    if (height > ((size_t)(-1))/rowbytes) {
+        fprintf(stderr, PROGNAME ":  image_data buffer would be too large\n",
+        return NULL;
+    }
+
     if ((image_data = (uch *)malloc(rowbytes*height)) == NULL) {
         return NULL;
     }
 
-    Trace((stderr, "readpng_get_image:  rowbytes = %ld, height = %ld\n", rowbytes, height));
-
-
     /* now we can go ahead and just read the whole image */
 
-    fread(image_data, 1L, rowbytes*height, saved_infile);
+    if (fread(image_data, 1L, rowbytes*height, saved_infile) <
-
+       rowbytes*height) {
+        free (image_data);
+        image_data = NULL;
+        return NULL;
+    }
 
     return image_data;
 }

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
@@ -182,7 +183,7 @@ int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, PSTR cmd, int showmode)
 #ifndef __CYGWIN__
     /* First reenable console output, which normally goes to the bit bucket
      * for windowed apps.  Closing the console window will terminate the
-     * app.  Thanks to David.Geldreich@realviz.com for supplying the magical
+     * app.  Thanks to David.Geldreich at realviz.com for supplying the magical
      * incantation. */
 
     AllocConsole();
@@ -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

@@ -26,10 +26,13 @@
     - 1.14:  added support for X resources (thanks to Gerhard Niklasch)
     - 2.00:  dual-licensed (added GNU GPL)
     - 2.01:  fixed improper display of usage screen on PNG error(s)
+    - 2.02:  Added "void(argc);" statement to quiet pedantic compiler warnings
+             about unused variable (GR-P)
+    - 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
@@ -80,7 +83,7 @@
 
 #define PROGNAME  "rpng-x"
 #define LONGNAME  "Simple PNG Viewer for X"
-#define VERSION   "2.01 of 16 March 2008"
+#define VERSION   "2.02 of 15 June 2014"
 #define RESNAME   "rpng"        /* our X resource application name */
 #define RESCLASS  "Rpng"        /* our X resource class name */
 
@@ -279,15 +282,17 @@ int main(int argc, char **argv)
           "Usage:  %s [-display xdpy] [-gamma exp] [-bgcolor bg] file.png\n"
           "    xdpy\tname of the target X display (e.g., ``hostname:0'')\n"
           "    exp \ttransfer-function exponent (``gamma'') of the display\n"
-          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n"
+          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n",
+          PROGNAME, default_display_exponent);
+
+        fprintf(stderr, "\n"
           "\t\t  to the product of the lookup-table exponent (varies)\n"
           "\t\t  and the CRT exponent (usually 2.2); must be positive\n"
           "    bg  \tdesired background color in 7-character hex RGB format\n"
           "\t\t  (e.g., ``#ff7700'' for orange:  same as HTML colors);\n"
           "\t\t  used with transparent images\n"
           "\nPress Q, Esc or mouse button 1 (within image window, after image\n"
-          "is displayed) to quit.\n"
+          "is displayed) to quit.\n");
-          "\n", PROGNAME, default_display_exponent);
         exit(1);
     }
 
@@ -419,6 +424,8 @@ int main(int argc, char **argv)
 
     rpng_x_cleanup();
 
+    (void)argc; /* Unused */
+
     return 0;
 }
 

contrib/gregbook/rpng2-win.c

@@ -33,10 +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:  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
@@ -299,7 +300,7 @@ int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, PSTR cmd, int showmode)
 #ifndef __CYGWIN__
     /* Next reenable console output, which normally goes to the bit bucket
      * for windowed apps.  Closing the console window will terminate the
-     * app.  Thanks to David.Geldreich@realviz.com for supplying the magical
+     * app.  Thanks to David.Geldreich at realviz.com for supplying the magical
      * incantation. */
 
     AllocConsole();
@@ -648,6 +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

@@ -41,10 +41,14 @@
               unexpected-EOF and file-read-error cases; fixed Trace() cut-and-
               paste bugs
     - 2.03:  deleted runtime MMX-enabling/disabling and obsolete -mmx* options
-
+    - 2.04:  Added "void(foo);" statements to quiet pedantic compiler warnings
+             about unused variables (GR-P)
+    - 2.05:  Use nanosleep() instead of usleep(), which is deprecated (GR-P).
+    - 2.06:  check for integer overflow (Glenn R-P)
   ---------------------------------------------------------------------------
 
-      Copyright (c) 1998-2008 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
@@ -95,7 +99,7 @@
 
 #define PROGNAME  "rpng2-x"
 #define LONGNAME  "Progressive PNG Viewer for X"
-#define VERSION   "2.03 of 25 February 2010"
+#define VERSION   "2.04 of 15 June 2014"
 #define RESNAME   "rpng2"       /* our X resource application name */
 #define RESCLASS  "Rpng"       /* our X resource class name */
 
@@ -111,6 +115,19 @@
 #include <X11/Xos.h>
 #include <X11/keysym.h>   /* defines XK_* macros */
 
+#if _POSIX_C_SOURCE >= 199309L /* have nanosleep() */
+# undef usleep
+# define usleep(usec) {        \
+   struct timespec ts;         \
+   ts.tv_sec = 0;              \
+   ts.tv_nsec = (usec) * 1000; \
+   nanosleep(&ts, NULL); }
+#  endif
+
+#ifndef usleep /* have neither nanosleep() nor usleep() */
+#  define usleep(x) sleep(((x)+499999)/1000000)
+#endif
+
 #ifdef VMS
 #  include <unistd.h>
 #endif
@@ -456,40 +473,47 @@ int main(int argc, char **argv)
         fprintf(stderr, "\n%s %s:  %s\n\n", PROGNAME, VERSION, appname);
         readpng2_version_info();
         fprintf(stderr, "\n"
-          "Usage:  %s [-display xdpy] [-gamma exp] [-bgcolor bg | -bgpat pat]\n"
+          "Usage:   ");
+        fprintf(stderr,
+          "%s [-display xdpy] [-gamma exp] [-bgcolor bg | -bgpat pat]\n"
+          "        %*s [-usleep dur | -timing] [-pause]\n",
+          PROGNAME, (int)strlen(PROGNAME), " ");
+        fprintf(stderr,
 #ifdef FEATURE_LOOP
-          "        %*s [-usleep dur | -timing] [-pause] [-loop [sec]] file.png\n\n"
+          "        [-loop [sec]]"
-#else
-          "        %*s [-usleep dur | -timing] [-pause] file.png\n\n"
 #endif
+          " file.png\n\n");
+        fprintf(stderr,
           "    xdpy\tname of the target X display (e.g., ``hostname:0'')\n"
           "    exp \ttransfer-function exponent (``gamma'') of the display\n"
           "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n"
-          "\t\t  to the product of the lookup-table exponent (varies)\n"
+          "\t\t  to the product of the lookup-table exponent (varies)\n",
+          default_display_exponent);
+        fprintf(stderr,
           "\t\t  and the CRT exponent (usually 2.2); must be positive\n"
           "    bg  \tdesired background color in 7-character hex RGB format\n"
           "\t\t  (e.g., ``#ff7700'' for orange:  same as HTML colors);\n"
           "\t\t  used with transparent images; overrides -bgpat\n"
           "    pat \tdesired background pattern number (0-%d); used with\n"
-          "\t\t  transparent images; overrides -bgcolor\n"
+          "\t\t  transparent images; overrides -bgcolor\n",
+          num_bgpat-1);
 #ifdef FEATURE_LOOP
+        fprintf(stderr,
           "    -loop\tloops through background images after initial display\n"
           "\t\t  is complete (depends on -bgpat)\n"
-          "    sec \tseconds to display each background image (default = 2)\n"
+          "    sec \tseconds to display each background image (default = 2)\n");
 #endif
+        fprintf(stderr,
           "    dur \tduration in microseconds to wait after displaying each\n"
           "\t\t  row (for demo purposes)\n"
           "    -timing\tenables delay for every block read, to simulate modem\n"
           "\t\t  download of image (~36 Kbps)\n"
           "    -pause\tpauses after displaying each pass until mouse clicked\n"
           "\nPress Q, Esc or mouse button 1 (within image window, after image\n"
-          "is displayed) to quit.\n"
+          "is displayed) to quit.\n");
-          "\n", PROGNAME,
-          (int)strlen(PROGNAME), " ", default_display_exponent, num_bgpat-1);
         exit(1);
     }
 
-
     if (!(infile = fopen(filename, "rb"))) {
         fprintf(stderr, PROGNAME ":  can't open PNG file [%s]\n", filename);
         ++error;
@@ -735,6 +759,8 @@ int main(int argc, char **argv)
     Trace((stderr, "about to call rpng2_x_cleanup()\n"))
     rpng2_x_cleanup();
 
+    (void)argc; /* Unused */
+
     return 0;
 }
 
@@ -756,6 +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);
@@ -1826,6 +1859,9 @@ static void rpng2_x_redisplay_image(ulg startcol, ulg startrow,
         XFlush(display);
     }
 
+    (void)startcol;
+    (void)width;
+
 } /* end function rpng2_x_redisplay_image() */
 
 

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
@@ -90,7 +90,7 @@ int writepng_init(mainprog_info *mainprog_ptr)
 
     /* could also replace libpng warning-handler (final NULL), but no need: */
 
-    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, mainprog_ptr,
+    png_ptr = png_create_write_struct(png_get_libpng_ver(NULL), mainprog_ptr,
       writepng_error_handler, NULL);
     if (!png_ptr)
         return 4;   /* out of memory */

contrib/libtests/fakepng.c

@@ -1,4 +1,12 @@
-/* Fake a PNG - just write it out directly. */
+/* Fake a PNG - just write it out directly.
+ *
+ * COPYRIGHT: Written by John Cunningham Bowler, 2014.
+ * To the extent possible under law, the author has waived all copyright and
+ * related or neighboring rights to this work.  This work is published from:
+ * United States.
+ *
+ */
+
 #include <stdio.h>
 #include <zlib.h> /* for crc32 */
 
@@ -52,6 +60,6 @@ main(void)
    fwrite(signature, sizeof signature, 1, stdout);
    put_chunk(IHDR, sizeof IHDR);
 
-   for(;;)
+   for (;;)
       put_chunk(unknown, sizeof unknown);
 }

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

@@ -1,17 +1,16 @@
-/* makepng.c
+/* makepng.c */
- *
+#define _ISOC99_SOURCE
- * Copyright (c) 2013 John Cunningham Bowler
+/* Copyright: */
- *
+#define COPYRIGHT "\251 2013,2015 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
  *
  * Make a test PNG image.  The arguments are as follows:
  *
- *  makepng [--sRGB|--linear|--1.8] [--color=<color>] color-type bit-depth \
+ *    makepng [--sRGB|--linear|--1.8] [--tRNS] [--nofilters] \
- *      [file-name]
+ *       color-type bit-depth [file-name]
  *
  * The color-type may be numeric (and must match the numbers used by the PNG
  * specification) or one of the format names listed below.  The bit-depth is the
@@ -39,8 +38,8 @@
  * 4 channels: linear combinations of, from the top-left corner clockwise,
  *    transparent, red, green, blue.
  *
- * For color-mapped images a four channel color-map is used and the PNG file has
+ * For color-mapped images a four channel color-map is used and if --tRNS is
- * a tRNS chunk, as follows:
+ * given the PNG file has a tRNS chunk, as follows:
  *
  * 1-bit: entry 0 is transparent-red, entry 1 is opaque-white
  * 2-bit: entry 0: transparent-green
@@ -53,6 +52,9 @@
  * The palette always has 2^bit-depth entries and the tRNS chunk one fewer.  The
  * image is the 1-channel diamond, but using palette index, not luminosity.
  *
+ * For formats other than color-mapped ones if --tRNS is specified a tRNS chunk
+ * is generated with all channels equal to the low bits of 0x0101.
+ *
  * Image size is determined by the final pixel depth in bits, i.e. channels x
  * bit-depth, as follows:
  *
@@ -60,20 +62,64 @@
  * 16 bits:           256x256
  * More than 16 bits: 1024x1024
  *
- * Row filtering is turned off (the 'none' filter is used on every row) and the
+ * Row filtering is the libpng default but may be turned off (the 'none' filter
- * images are not interlaced.
+ * is used on every row) with the --nofilters option.
+ *
+ * The images are not interlaced.
+ *
+ * If file-name is given then the PNG is written to that file, else it is
+ * written to stdout.  Notice that stdout is not supported on systems where, by
+ * default, it assumes text output; this program makes no attempt to change the
+ * text mode of stdout!
+ *
+ *    makepng --color=<color> ...
  *
  * If --color is given then the whole image has that color, color-mapped images
  * will have exactly one palette entry and all image files with be 16x16 in
  * size.  The color value is 1 to 4 decimal numbers as appropriate for the color
  * type.
  *
- * If file-name is given then the PNG is written to that file, else it is
+ *    makepng --small ...
- * written to stdout.  Notice that stdout is not supported on systems where, by
+ *
- * default, it assumes text output; this program makes no attempt to change the
+ * If --small is given the images are no larger than required to include every
- * text mode of stdout!
+ * possible pixel value for the format.
+ *
+ * For formats with pixels 8 bits or fewer in size the images consist of a
+ * single row with 2^pixel-depth pixels, one of every possible value.
+ *
+ * For formats with 16-bit pixels a 256x256 image is generated containing every
+ * possible pixel value.
+ *
+ * For larger pixel sizes a 256x256 image is generated where the first row
+ * consists of each pixel that has identical byte values throughout the pixel
+ * followed by rows where the byte values differ within the pixel.
+ *
+ * In all cases the pixel values are arranged in such a way that the SUB and UP
+ * filters give byte sequences for maximal zlib compression.  By default (if
+ * --nofilters is not given) the SUB filter is used on the first row and the UP
+ * filter on all following rows.
+ *
+ * The --small option is meant to provide good test-case coverage, however the
+ * images are not easy to examine visually.  Without the --small option the
+ * images contain identical color values; the pixel values are adjusted
+ * according to the gamma encoding with no gamma encoding being interpreted as
+ * sRGB.
+ *
+ * LICENSING
+ * =========
+ *
+ * This code is copyright of the authors, see the COPYRIGHT define above.  The
+ * code is licensed as above, using the libpng license.  The code generates
+ * images which are solely the product of the code; the options choose which of
+ * the many possibilities to generate.  The images that result (but not the code
+ * which generates them) are licensed as defined here:
+ *
+ * IMPORTANT: the COPYRIGHT #define must contain ISO-Latin-1 characters, the
+ * IMAGE_LICENSING #define must contain UTF-8 characters.  The 'copyright'
+ * symbol 0xA9U (\251) in ISO-Latin-1 encoding and 0xC20xA9 (\302\251) in UTF-8.
  */
-#define _ISOC99_SOURCE /* for strtoull */
+#define IMAGE_LICENSING "Dedicated to the public domain per Creative Commons "\
+    "license \"CC0 1.0\"; https://creativecommons.org/publicdomain/zero/1.0/"
 
 #include <stddef.h> /* for offsetof */
 #include <stdlib.h>
@@ -82,6 +128,8 @@
 #include <ctype.h>
 #include <math.h>
 #include <errno.h>
+#include <assert.h>
+#include <stdint.h>
 
 #if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
 #  include <config.h>
@@ -96,6 +144,25 @@
 #  include "../../png.h"
 #endif
 
+#include <zlib.h>
+
+/* Work round for GCC complaints about casting a (double) function result to
+ * an unsigned:
+ */
+static unsigned int
+flooru(double d)
+{
+   d = floor(d);
+   return (unsigned int)d;
+}
+
+static png_byte
+floorb(double d)
+{
+   d = floor(d);
+   return (png_byte)d;
+}
+
 /* This structure is used for inserting extra chunks (the --insert argument, not
  * documented above.)
  */
@@ -107,7 +174,7 @@ typedef struct chunk_insert
    png_charp            parameters[1];
 } chunk_insert;
 
-static int
+static unsigned int
 channels_of_type(int color_type)
 {
    if (color_type & PNG_COLOR_MASK_PALETTE)
@@ -128,14 +195,15 @@ channels_of_type(int color_type)
    }
 }
 
-static int
+static unsigned int
 pixel_depth_of_type(int color_type, int bit_depth)
 {
    return channels_of_type(color_type) * bit_depth;
 }
 
 static unsigned int
-image_size_of_type(int color_type, int bit_depth, unsigned int *colors)
+image_size_of_type(int color_type, int bit_depth, unsigned int *colors,
+   int small)
 {
    if (*colors)
       return 16;
@@ -144,7 +212,16 @@ image_size_of_type(int color_type, int bit_depth, unsigned int *colors)
    {
       int pixel_depth = pixel_depth_of_type(color_type, bit_depth);
 
-      if (pixel_depth < 8)
+      if (small)
+      {
+         if (pixel_depth <= 8) /* there will be one row */
+            return 1 << pixel_depth;
+
+         else
+            return 256;
+      }
+
+      else if (pixel_depth < 8)
          return 64;
 
       else if (pixel_depth > 16)
@@ -217,27 +294,31 @@ generate_palette(png_colorp palette, png_bytep trans, int bit_depth,
          else
          {
             unsigned int size = 1U << (bit_depth/2); /* 2, 4 or 16 */
-            unsigned int x, y, ip;
+            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)
             {
-               ip = x + (size * y);
+               for (y=0; y<size; ++y)
+               {
+                  ip = x + (size * y);
 
-               /* size is at most 16, so the scaled value below fits in 16 bits
+                  /* size is at most 16, so the scaled value below fits in 16 bits
-                */
+                  */
-#              define interp(pos, c1, c2) ((pos * c1) + ((size-pos) * c2))
+#                 define interp(pos, c1, c2) ((pos * c1) + ((size-pos) * c2))
-#              define xyinterp(x, y, c1, c2, c3, c4) (((size * size / 2) +\
+#                 define xyinterp(x, y, c1, c2, c3, c4) (((size * size / 2) +\
-                  (interp(x, c1, c2) * y + (size-y) * interp(x, c3, c4))) /\
+                     (interp(x, c1, c2) * y + (size-y) * interp(x, c3, c4))) /\
-                  (size*size))
+                     (size*size))
 
-               set_color(palette+ip, trans+ip,
+                  set_color(palette+ip, trans+ip,
-                  /* color:    green, red,blue,white */
+                     /* color:    green, red,blue,white */
-                  xyinterp(x, y,   0, 255,   0, 255),
+                     xyinterp(x, y,   0, 255,   0, 255),
-                  xyinterp(x, y, 255,   0,   0, 255),
+                     xyinterp(x, y, 255,   0,   0, 255),
-                  xyinterp(x, y,   0,   0, 255, 255),
+                     xyinterp(x, y,   0,   0, 255, 255),
-                  /* alpha:        0, 102, 204, 255) */
+                     /* alpha:        0, 102, 204, 255) */
-                  xyinterp(x, y,   0, 102, 204, 255),
+                     xyinterp(x, y,   0, 102, 204, 255),
-                  gamma_table);
+                     gamma_table);
+               }
             }
 
             return ip+1;
@@ -281,7 +362,7 @@ set_value(png_bytep row, size_t rowbytes, png_uint_32 x, unsigned int bit_depth,
                exit(1);
 
             case 16:
-               value = (unsigned int)floor(65535*pow(value/65535.,conv)+.5);
+               value = flooru(65535*pow(value/65535.,conv)+.5);
                *row++ = (png_byte)(value >> 8);
                *row = (png_byte)value;
                return;
@@ -306,15 +387,148 @@ set_value(png_bytep row, size_t rowbytes, png_uint_32 x, unsigned int bit_depth,
    }
 }
 
-static void
+static int /* filter mask for row */
 generate_row(png_bytep row, size_t rowbytes, unsigned int y, int color_type,
    int bit_depth, png_const_bytep gamma_table, double conv,
-   unsigned int *colors)
+   unsigned int *colors, int small)
 {
-   png_uint_32 size_max = image_size_of_type(color_type, bit_depth, colors)-1;
+   int filters = 0; /* file *MASK*, 0 means the default, not NONE */
+   png_uint_32 size_max =
+      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) switch (channels_of_type(color_type))
+   if (colors[0] == 0 && small)
+   {
+      unsigned int pixel_depth = pixel_depth_of_type(color_type, bit_depth);
+
+      /* For pixel depths less than 16 generate a single row containing all the
+       * possible pixel values.  For 16 generate all 65536 byte pair
+       * combinations in a 256x256 pixel array.
+       */
+      switch (pixel_depth)
+      {
+         case 1:
+            assert(y == 0 && rowbytes == 1 && size_max == 1);
+            row[0] = 0x6CU; /* binary: 01101100, only top 2 bits used */
+            filters = PNG_FILTER_NONE;
+            break;
+
+         case 2:
+            assert(y == 0 && rowbytes == 1 && size_max == 3);
+            row[0] = 0x1BU; /* binary 00011011, all bits used */
+            filters = PNG_FILTER_NONE;
+            break;
+
+         case 4:
+            assert(y == 0 && rowbytes == 8 && size_max == 15);
+            row[0] = 0x01U;
+            row[1] = 0x23U; /* SUB gives 0x22U for all following bytes */
+            row[2] = 0x45U;
+            row[3] = 0x67U;
+            row[4] = 0x89U;
+            row[5] = 0xABU;
+            row[6] = 0xCDU;
+            row[7] = 0xEFU;
+            filters = PNG_FILTER_SUB;
+            break;
+
+         case 8:
+            /* The row will have all the pixel values in order starting with
+             * '1', the SUB filter will change every byte into '1' (including
+             * the last, which generates pixel value '0').  Since the SUB filter
+             * has value 1 this should result in maximum compression.
+             */
+            assert(y == 0 && rowbytes == 256 && size_max == 255);
+            for (;;)
+            {
+               row[size_max] = 0xFFU & (size_max+1);
+               if (size_max == 0)
+                  break;
+               --size_max;
+            }
+            filters = PNG_FILTER_SUB;
+            break;
+
+         case 16:
+            /* Rows are generated such that each row has a constant difference
+             * between the first and second byte of each pixel and so that the
+             * difference increases by 1 at each row.  The rows start with the
+             * first byte value of 0 and the value increases to 255 across the
+             * row.
+             *
+             * The difference starts at 1, so the first row is:
+             *
+             *     0 1 1 2 2 3 3 4 ... 254 255 255 0
+             *
+             * This means that running the SUB filter on the first row produces:
+             *
+             *   [SUB==1] 0 1 0 1 0 1...
+             *
+             * Then the difference is 2 on the next row, giving:
+             *
+             *    0 2 1 3 2 4 3 5 ... 254 0 255 1
+             *
+             * When the UP filter is run on this libpng produces:
+             *
+             *   [UP ==2] 0 1 0 1 0 1...
+             *
+             * And so on for all the remain rows to the final two * rows:
+             *
+             *    row 254: 0 255 1 0 2 1 3 2 4 3 ... 254 253 255 254
+             *    row 255: 0   0 1 1 2 2 3 3 4 4 ... 254 254 255 255
+             */
+            assert(rowbytes == 512 && size_max == 255);
+            for (;;)
+            {
+               row[2*size_max  ] = 0xFFU & size_max;
+               row[2*size_max+1] = 0xFFU & (size_max+y+1);
+               if (size_max == 0)
+                  break;
+               --size_max;
+            }
+            /* The first row must include PNG_FILTER_UP so that libpng knows we
+             * need to keep it for the following row:
+             */
+            filters = (y == 0 ? PNG_FILTER_SUB+PNG_FILTER_UP : PNG_FILTER_UP);
+            break;
+
+         case 24:
+         case 32:
+         case 48:
+         case 64:
+            /* 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
+             * number ensures all the possible byte values are used.
+             */
+            assert(size_max == 255 && rowbytes == 256*(pixel_depth>>3));
+            pixel_depth >>= 3; /* now in bytes */
+            while (rowbytes > 0)
+            {
+               const size_t pixel_index = --rowbytes/pixel_depth;
+
+               if (y == 0)
+                  row[rowbytes] = 0xFFU & pixel_index;
+
+               else
+               {
+                  const size_t byte_offset =
+                     rowbytes - pixel_index * pixel_depth;
+
+                  row[rowbytes] =
+                     0xFFU & (pixel_index + (byte_offset * 2*y) + 1);
+               }
+            }
+            filters = (y == 0 ? PNG_FILTER_SUB+PNG_FILTER_UP : PNG_FILTER_UP);
+            break;
+
+         default:
+            assert(0/*NOT REACHED*/);
+      }
+   }
+
+   else switch (channels_of_type(color_type))
    {
    /* 1 channel: a square image with a diamond, the least luminous colors are on
     *    the edge of the image, the most luminous in the center.
@@ -448,7 +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)
@@ -459,8 +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)
@@ -475,9 +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)
@@ -494,10 +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)
@@ -526,6 +740,8 @@ generate_row(png_bytep row, size_t rowbytes, unsigned int y, int color_type,
          colors[0], channels_of_type(color_type));
       exit(1);
    }
+
+   return filters;
 }
 
 
@@ -554,7 +770,7 @@ makepng_error(png_structp png_ptr, png_const_charp message)
 static int /* 0 on success, else an error code */
 write_png(const char **name, FILE *fp, int color_type, int bit_depth,
    volatile png_fixed_point gamma, chunk_insert * volatile insert,
-   unsigned int filters, unsigned int *colors)
+   unsigned int filters, unsigned int *colors, int small, int tRNS)
 {
    png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,
       name, makepng_error, makepng_warning);
@@ -581,6 +797,15 @@ write_png(const char **name, FILE *fp, int color_type, int bit_depth,
 
    /* Allow benign errors so that we can write PNGs with errors */
    png_set_benign_errors(png_ptr, 1/*allowed*/);
+
+   /* Max out the text compression level in an attempt to make the license
+    * small.   If --small then do the same for the IDAT.
+    */
+   if (small)
+      png_set_compression_level(png_ptr, Z_BEST_COMPRESSION);
+
+   png_set_text_compression_level(png_ptr, Z_BEST_COMPRESSION);
+
    png_init_io(png_ptr, fp);
 
    info_ptr = png_create_info_struct(png_ptr);
@@ -588,11 +813,37 @@ write_png(const char **name, FILE *fp, int color_type, int bit_depth,
       png_error(png_ptr, "OOM allocating info structure");
 
    {
-      unsigned int size = image_size_of_type(color_type, bit_depth, colors);
+      unsigned int size =
+         image_size_of_type(color_type, bit_depth, colors, small);
+      unsigned int ysize;
       png_fixed_point real_gamma = 45455; /* For sRGB */
       png_byte gamma_table[256];
       double conv;
 
+      /* Normally images are square, but with 'small' we want to simply generate
+       * all the pixel values, or all that we reasonably can:
+       */
+      if (small)
+      {
+         unsigned int pixel_depth =
+            pixel_depth_of_type(color_type, bit_depth);
+
+         if (pixel_depth <= 8U)
+         {
+            assert(size == (1U<<pixel_depth));
+            ysize = 1U;
+         }
+
+         else
+         {
+            assert(size == 256U);
+            ysize = 256U;
+         }
+      }
+
+      else
+         ysize = size;
+
       /* This function uses the libpng values used on read to carry extra
        * information about the gamma:
        */
@@ -608,10 +859,13 @@ 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)
          {
-            gamma_table[i] = (png_byte)i;
+            for (i=0; i<256; ++i)
-            conv = 1.;
+            {
+               gamma_table[i] = (png_byte)i;
+               conv = 1.;
+            }
          }
 
          else
@@ -625,13 +879,13 @@ write_png(const char **name, FILE *fp, int color_type, int bit_depth,
             gamma_table[0] = 0;
 
             for (i=1; i<255; ++i)
-               gamma_table[i] = (png_byte)floor(pow(i/255.,conv) * 255 + .5);
+               gamma_table[i] = floorb(pow(i/255.,conv) * 255 + .5);
 
             gamma_table[255] = 255;
          }
       }
 
-      png_set_IHDR(png_ptr, info_ptr, size, size, bit_depth, color_type,
+      png_set_IHDR(png_ptr, info_ptr, size, ysize, bit_depth, color_type,
          PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
 
       if (color_type & PNG_COLOR_MASK_PALETTE)
@@ -643,14 +897,26 @@ write_png(const char **name, FILE *fp, int color_type, int bit_depth,
          npalette = generate_palette(palette, trans, bit_depth, gamma_table,
             colors);
          png_set_PLTE(png_ptr, info_ptr, palette, npalette);
-         png_set_tRNS(png_ptr, info_ptr, trans, npalette-1,
+
-            NULL/*transparent color*/);
+         if (tRNS)
+            png_set_tRNS(png_ptr, info_ptr, trans, npalette-1,
+               NULL/*transparent color*/);
 
          /* Reset gamma_table to prevent the image rows being changed */
          for (npalette=0; npalette<256; ++npalette)
             gamma_table[npalette] = (png_byte)npalette;
       }
 
+      else if (tRNS)
+      {
+         png_color_16 col;
+
+         col.red = col.green = col.blue = col.gray =
+            0x0101U & ((1U<<bit_depth)-1U);
+         col.index = 0U;
+         png_set_tRNS(png_ptr, info_ptr, NULL/*trans*/, 1U, &col);
+      }
+
       if (gamma == PNG_DEFAULT_sRGB)
          png_set_sRGB(png_ptr, info_ptr, PNG_sRGB_INTENT_ABSOLUTE);
 
@@ -682,9 +948,13 @@ write_png(const char **name, FILE *fp, int color_type, int bit_depth,
       png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE, filters);
 
       {
-         int passes = png_set_interlace_handling(png_ptr);
+#        ifdef PNG_WRITE_INTERLACING_SUPPORTED
+            int passes = png_set_interlace_handling(png_ptr);
+#        else /* !WRITE_INTERLACING */
+            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);
 
@@ -695,10 +965,15 @@ write_png(const char **name, FILE *fp, int color_type, int bit_depth,
          {
             unsigned int y;
 
-            for (y=0; y<size; ++y)
+            for (y=0; y<ysize; ++y)
             {
-               generate_row(row, rowbytes, y, color_type, bit_depth,
+               unsigned int row_filters =
-                  gamma_table, conv, colors);
+                  generate_row(row, rowbytes, y, color_type, bit_depth,
+                        gamma_table, conv, colors, small);
+
+               if (row_filters != 0 && filters == PNG_ALL_FILTERS)
+                  png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE, row_filters);
+
                png_write_row(png_ptr, row);
             }
          }
@@ -823,11 +1098,11 @@ 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;
-   unsigned long long int size = strtoull(param, &endptr, 0/*base*/);
+   uint64_t size = strtoull(param, &endptr, 0/*base*/);
 
    /* The 'fake' format is <number>*[string] */
    if (endptr != NULL && *endptr == '*')
@@ -893,7 +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",
@@ -908,7 +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 */
             {
@@ -1003,7 +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 */
             {
@@ -1062,7 +1337,8 @@ insert_iTXt(png_structp png_ptr, png_infop info_ptr, int nparams,
 }
 
 static void
-insert_hIST(png_structp png_ptr, png_infop info_ptr, int nparams, png_charpp params)
+insert_hIST(png_structp png_ptr, png_infop info_ptr, int nparams,
+      png_charpp params)
 {
    int i;
    png_uint_16 freq[256];
@@ -1089,6 +1365,56 @@ insert_hIST(png_structp png_ptr, png_infop info_ptr, int nparams, png_charpp par
    png_set_hIST(png_ptr, info_ptr, freq);
 }
 
+static png_byte
+bval(png_const_structrp png_ptr, png_charp param, unsigned int maxval)
+{
+   char *endptr = NULL;
+   unsigned long int l = strtoul(param, &endptr, 0/*base*/);
+
+   if (param[0] && *endptr == 0 && l <= maxval)
+      return (png_byte)l;
+
+   else
+      png_error(png_ptr, "sBIT: invalid sBIT value");
+}
+
+static void
+insert_sBIT(png_structp png_ptr, png_infop info_ptr, int nparams,
+      png_charpp params)
+{
+   int ct = png_get_color_type(png_ptr, info_ptr);
+   int c = (ct & PNG_COLOR_MASK_COLOR ? 3 : 1) +
+      (ct & PNG_COLOR_MASK_ALPHA ? 1 : 0);
+   unsigned int maxval =
+      ct & PNG_COLOR_MASK_PALETTE ? 8U : png_get_bit_depth(png_ptr, info_ptr);
+   png_color_8 sBIT;
+
+   if (nparams != c)
+      png_error(png_ptr, "sBIT: incorrect parameter count");
+
+   if (ct & PNG_COLOR_MASK_COLOR)
+   {
+      sBIT.red = bval(png_ptr, params[0], maxval);
+      sBIT.green = bval(png_ptr, params[1], maxval);
+      sBIT.blue = bval(png_ptr, params[2], maxval);
+      sBIT.gray = 42;
+   }
+
+   else
+   {
+      sBIT.red = sBIT.green = sBIT.blue = 42;
+      sBIT.gray = bval(png_ptr, params[0], maxval);
+   }
+
+   if (ct & PNG_COLOR_MASK_ALPHA)
+      sBIT.alpha = bval(png_ptr, params[nparams-1], maxval);
+
+   else
+      sBIT.alpha = 42;
+
+   png_set_sBIT(png_ptr, info_ptr, &sBIT);
+}
+
 #if 0
 static void
 insert_sPLT(png_structp png_ptr, png_infop info_ptr, int nparams, png_charpp params)
@@ -1108,10 +1434,13 @@ 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)
       {
-         *param++ = 0; /* Terminate last parameter */
+         if (*param == '\n' || *param == ':')
-         break;        /* And start a new one. */
+         {
+            *param++ = 0; /* Terminate last parameter */
+            break;        /* And start a new one. */
+         }
       }
    }
 
@@ -1216,6 +1545,11 @@ find_insert(png_const_charp what, png_charp param)
             return make_insert(what, insert_hIST, nparams, parameter_list);
          break;
 
+      case CHUNK(115,66,73,84): /* sBIT */
+         if (nparams <= 4)
+            return make_insert(what, insert_sBIT, nparams, parameter_list);
+         break;
+
 #if 0
       case CHUNK(115,80,76,84):  /* sPLT */
          return make_insert(what, insert_sPLT, nparams, parameter_list);
@@ -1231,6 +1565,80 @@ find_insert(png_const_charp what, png_charp param)
    return NULL;
 }
 
+/* This is necessary because libpng expects writeable strings for things like
+ * text chunks (maybe this should be fixed...)
+ */
+static png_charp
+strstash(png_const_charp foo)
+{
+   /* The program indicates a memory allocation error by crashing, this is by
+    * design.
+    */
+   if (foo != NULL)
+   {
+      png_charp bar = malloc(strlen(foo)+1);
+      return strcpy(bar, foo);
+   }
+
+   return NULL;
+}
+
+static png_charp
+strstash_list(const png_const_charp *text)
+{
+   size_t foo = 0;
+   png_charp result, bar;
+   const png_const_charp *line = text;
+
+   while (*line != NULL)
+      foo += strlen(*line++);
+
+   result = bar = malloc(foo+1);
+
+   line = text;
+   while (*line != NULL)
+   {
+      foo = strlen(*line);
+      memcpy(bar, *line++, foo);
+      bar += foo;
+   }
+
+   *bar = 0;
+   return result;
+}
+
+/* These are used to insert Copyright and Licence fields, they allow the text to
+ * have \n unlike the --insert option.
+ */
+static chunk_insert *
+add_tEXt(const char *key, const png_const_charp *text)
+{
+   static char what[5] = { 116, 69, 88, 116, 0 };
+   png_charp parameter_list[3];
+
+   parameter_list[0] = strstash(key);
+   parameter_list[1] = strstash_list(text);
+   parameter_list[2] = NULL;
+
+   return make_insert(what, insert_tEXt, 2, parameter_list);
+}
+
+static chunk_insert *
+add_iTXt(const char *key, const char *language, const char *language_key,
+      const png_const_charp *text)
+{
+   static char what[5] = { 105, 84, 88, 116, 0 };
+   png_charp parameter_list[5];
+
+   parameter_list[0] = strstash(key);
+   parameter_list[1] = strstash(language);
+   parameter_list[2] = strstash(language_key);
+   parameter_list[3] = strstash_list(text);
+   parameter_list[4] = NULL;
+
+   return make_insert(what, insert_iTXt, 4, parameter_list);
+}
+
 /* This is a not-very-good parser for a sequence of numbers (including 0).  It
  * doesn't accept some apparently valid things, but it accepts all the sensible
  * combinations.
@@ -1280,6 +1688,8 @@ main(int argc, char **argv)
    const char *file_name = NULL;
    int color_type = 8; /* invalid */
    int bit_depth = 32; /* invalid */
+   int small = 0; /* make full size images */
+   int tRNS = 0; /* don't output a tRNS chunk */
    unsigned int colors[5];
    unsigned int filters = PNG_ALL_FILTERS;
    png_fixed_point gamma = 0; /* not set */
@@ -1292,6 +1702,18 @@ main(int argc, char **argv)
    {
       char *arg = *++argv;
 
+      if (strcmp(arg, "--small") == 0)
+      {
+         small = 1;
+         continue;
+      }
+
+      if (strcmp(arg, "--tRNS") == 0)
+      {
+         tRNS = 1;
+         continue;
+      }
+
       if (strcmp(arg, "--sRGB") == 0)
       {
          gamma = PNG_DEFAULT_sRGB;
@@ -1432,15 +1854,16 @@ main(int argc, char **argv)
 
    if (color_type == 8 || bit_depth == 32)
    {
-      fprintf(stderr, "usage: makepng [--sRGB|--linear|--1.8] "
+      fprintf(stderr, "usage: makepng [--small] [--sRGB|--linear|--1.8] "
          "[--color=...] color-type bit-depth [file-name]\n"
-         "  Make a test PNG file, by default writes to stdout.\n");
+         "  Make a test PNG file, by default writes to stdout.\n"
+         "  Other options are available, UTSL.\n");
       exit(1);
    }
 
    /* 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;
 
@@ -1453,10 +1876,19 @@ main(int argc, char **argv)
          }
    }
 
+   /* small and colors are incompatible (will probably crash if both are used at
+    * the same time!)
+    */
+   if (small && colors[0] != 0)
+   {
+      fprintf(stderr, "makepng: --color --small: only one at a time!\n");
+      exit(1);
+   }
+
    /* Restrict the filters for more speed to those we know are used for the
     * generated images.
     */
-   if (filters == PNG_ALL_FILTERS)
+   if (filters == PNG_ALL_FILTERS && !small/*small provides defaults*/)
    {
       if ((color_type & PNG_COLOR_MASK_PALETTE) != 0 || bit_depth < 8)
          filters = PNG_FILTER_NONE;
@@ -1474,9 +1906,39 @@ main(int argc, char **argv)
          filters &= ~PNG_FILTER_NONE;
    }
 
+   /* Insert standard copyright and licence text. */
+   {
+      static png_const_charp copyright[] =
+      {
+         COPYRIGHT, /* ISO-Latin-1 */
+         NULL
+      };
+      static png_const_charp licensing[] =
+      {
+         IMAGE_LICENSING, /* UTF-8 */
+         NULL
+      };
+
+      chunk_insert *new_insert;
+
+      new_insert = add_tEXt("Copyright", copyright);
+      if (new_insert != NULL)
+      {
+         *insert_ptr = new_insert;
+         insert_ptr = &new_insert->next;
+      }
+
+      new_insert = add_iTXt("Licensing", "en", NULL, licensing);
+      if (new_insert != NULL)
+      {
+         *insert_ptr = new_insert;
+         insert_ptr = &new_insert->next;
+      }
+   }
+
    {
       int ret = write_png(&file_name, fp, color_type, bit_depth, gamma,
-         head_insert, filters, colors);
+         head_insert, filters, colors, small, tRNS);
 
       if (ret != 0 && file_name != NULL)
          remove(file_name);

contrib/libtests/pngimage.c

@@ -1,8 +1,8 @@
+
 /* pngimage.c
  *
- * Copyright (c) 2014 John Cunningham Bowler
+ * Copyright (c) 2021 Cosmin Truta
- *
+ * Copyright (c) 2015,2016 John Cunningham Bowler
- * 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
@@ -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>
@@ -36,7 +37,28 @@
 #  include <setjmp.h> /* because png.h did *not* include this */
 #endif
 
-#if defined(PNG_INFO_IMAGE_SUPPORTED) && defined(PNG_SEQUENTIAL_READ_SUPPORTED)
+/* 1.6.1 added support for the configure test harness, which uses 77 to indicate
+ * a skipped test, in earlier versions we need to succeed on a skipped test, so:
+ */
+#if PNG_LIBPNG_VER >= 10601 && defined(HAVE_CONFIG_H)
+#  define SKIP 77
+#else
+#  define SKIP 0
+#endif
+
+#if PNG_LIBPNG_VER < 10700
+   /* READ_PNG and WRITE_PNG were not defined, so: */
+#  ifdef PNG_INFO_IMAGE_SUPPORTED
+#     ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+#        define PNG_READ_PNG_SUPPORTED
+#     endif /* SEQUENTIAL_READ */
+#     ifdef PNG_WRITE_SUPPORTED
+#        define PNG_WRITE_PNG_SUPPORTED
+#     endif /* WRITE */
+#  endif /* INFO_IMAGE */
+#endif /* pre 1.7.0 */
+
+#ifdef PNG_READ_PNG_SUPPORTED
 /* If a transform is valid on both read and write this implies that if the
  * transform is applied to read it must also be applied on write to produce
  * meaningful data.  This is because these transforms when performed on read
@@ -236,10 +258,12 @@ static struct transform_info
        */
 #endif
 #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
-   T(SCALE_16,            NONE, X,   X,   16,  R)
+   T(SCALE_16,            NONE, X,   X,   16,  R),
       /* scales 16-bit components to 8-bits. */
 #endif
 
+   { NULL /*name*/, 0, 0, 0, 0, 0, 0, 0/*!tested*/ }
+
 #undef T
 };
 
@@ -295,10 +319,9 @@ transform_name(int t)
    t &= -t; /* first set bit */
 
    for (i=0; i<TTABLE_SIZE; ++i)
-   {
+      if (transform_info[i].name != NULL)
-      if ((transform_info[i].transform & t) != 0)
+         if ((transform_info[i].transform & t) != 0)
-         return transform_info[i].name;
+            return transform_info[i].name;
-   }
 
    return "invalid transform";
 }
@@ -317,11 +340,14 @@ validate_T(void)
 
    for (i=0; i<TTABLE_SIZE; ++i)
    {
-      if (transform_info[i].when & TRANSFORM_R)
+      if (transform_info[i].name != NULL)
-         read_transforms |= transform_info[i].transform;
+      {
+         if (transform_info[i].when & TRANSFORM_R)
+            read_transforms |= transform_info[i].transform;
 
-      if (transform_info[i].when & TRANSFORM_W)
+         if (transform_info[i].when & TRANSFORM_W)
-         write_transforms |= transform_info[i].transform;
+            write_transforms |= transform_info[i].transform;
+      }
    }
 
    /* Reversible transforms are those which are supported on both read and
@@ -337,6 +363,9 @@ validate_T(void)
  *    In both cases the file data is held in a linked list of buffers - not all
  *    of these are in use at any time.
  */
+#define NEW(type) ((type *)malloc(sizeof (type)))
+#define DELETE(ptr) (free(ptr))
+
 struct buffer_list
 {
    struct buffer_list *next;         /* next buffer in list */
@@ -361,7 +390,26 @@ buffer_init(struct buffer *buffer)
    buffer->current = NULL;
 }
 
-#ifdef PNG_WRITE_SUPPORTED
+static void
+buffer_destroy_list(struct buffer_list *list)
+{
+   if (list != NULL)
+   {
+      struct buffer_list *next = list->next;
+      DELETE(list);
+      buffer_destroy_list(next);
+   }
+}
+
+static void
+buffer_destroy(struct buffer *buffer)
+{
+   struct buffer_list *list = buffer->first.next;
+   buffer_init(buffer);
+   buffer_destroy_list(list);
+}
+
+#ifdef PNG_WRITE_PNG_SUPPORTED
 static void
 buffer_start_write(struct buffer *buffer)
 {
@@ -390,8 +438,6 @@ get_buffer(png_structp pp)
    return (struct buffer*)png_get_io_ptr(pp);
 }
 
-#define NEW(type) ((type *)malloc(sizeof (type)))
-
 static struct buffer_list *
 buffer_extend(struct buffer_list *current)
 {
@@ -485,6 +531,7 @@ typedef enum
 #define SKIP_BUGS       0x100 /* Skip over known bugs */
 #define LOG_SKIPPED     0x200 /* Log skipped bugs */
 #define FIND_BAD_COMBOS 0x400 /* Attempt to deduce bad combos */
+#define LIST_COMBOS     0x800 /* List combos by name */
 
 /* Result masks apply to the result bits in the 'results' field below; these
  * bits are simple 1U<<error_level.  A pass requires either nothing worse than
@@ -507,7 +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 */
@@ -532,7 +579,7 @@ struct display
    png_structp    read_pp;
    png_infop      read_ip;
 
-#  ifdef PNG_WRITE_SUPPORTED
+#  ifdef PNG_WRITE_PNG_SUPPORTED
       /* Used to write a new image (the original info_ptr is used) */
       png_structp   write_pp;
       struct buffer written_file;   /* where the file gets written */
@@ -559,7 +606,7 @@ display_init(struct display *dp)
    dp->read_ip = NULL;
    buffer_init(&dp->original_file);
 
-#  ifdef PNG_WRITE_SUPPORTED
+#  ifdef PNG_WRITE_PNG_SUPPORTED
       dp->write_pp = NULL;
       buffer_init(&dp->written_file);
 #  endif
@@ -572,7 +619,7 @@ display_clean_read(struct display *dp)
       png_destroy_read_struct(&dp->read_pp, &dp->read_ip, NULL);
 }
 
-#ifdef PNG_WRITE_SUPPORTED
+#ifdef PNG_WRITE_PNG_SUPPORTED
 static void
 display_clean_write(struct display *dp)
 {
@@ -584,7 +631,7 @@ display_clean_write(struct display *dp)
 static void
 display_clean(struct display *dp)
 {
-#  ifdef PNG_WRITE_SUPPORTED
+#  ifdef PNG_WRITE_PNG_SUPPORTED
       display_clean_write(dp);
 #  endif
    display_clean_read(dp);
@@ -598,6 +645,17 @@ display_clean(struct display *dp)
    dp->results = 0; /* reset for next time */
 }
 
+static void
+display_destroy(struct display *dp)
+{
+    /* Release any memory held in the display. */
+#  ifdef PNG_WRITE_PNG_SUPPORTED
+      buffer_destroy(&dp->written_file);
+#  endif
+
+   buffer_destroy(&dp->original_file);
+}
+
 static struct display *
 get_dp(png_structp pp)
    /* The display pointer is always stored in the png_struct error pointer */
@@ -659,7 +717,35 @@ display_log(struct display *dp, error_level level, const char *fmt, ...)
          int tr = dp->transforms;
 
          if (is_combo(tr))
-            fprintf(stderr, "(0x%x)", tr);
+         {
+            if (dp->options & LIST_COMBOS)
+            {
+               int trx = tr;
+
+               fprintf(stderr, "(");
+               if (trx)
+               {
+                  int start = 0;
+
+                  while (trx)
+                  {
+                     int trz = trx & -trx;
+
+                     if (start) fprintf(stderr, "+");
+                     fprintf(stderr, "%s", transform_name(trz));
+                     start = 1;
+                     trx &= ~trz;
+                  }
+               }
+
+               else
+                  fprintf(stderr, "-");
+               fprintf(stderr, ")");
+            }
+
+            else
+               fprintf(stderr, "(0x%x)", tr);
+         }
 
          else
             fprintf(stderr, "(%s)", transform_name(tr));
@@ -724,7 +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;
@@ -772,7 +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);
 }
@@ -844,7 +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 */
@@ -881,19 +967,22 @@ update_display(struct display *dp)
 
       for (i=0; i<TTABLE_SIZE; ++i)
       {
-         int transform = transform_info[i].transform;
+         if (transform_info[i].name != NULL)
+         {
+            int transform = transform_info[i].transform;
 
-         if ((transform_info[i].valid_chunks == 0 ||
+            if ((transform_info[i].valid_chunks == 0 ||
-               (transform_info[i].valid_chunks & chunks) != 0) &&
+                  (transform_info[i].valid_chunks & chunks) != 0) &&
-            (transform_info[i].color_mask_required & ct) == 
+               (transform_info[i].color_mask_required & ct) ==
-               transform_info[i].color_mask_required &&
+                  transform_info[i].color_mask_required &&
-            (transform_info[i].color_mask_absent & ct) == 0 &&
+               (transform_info[i].color_mask_absent & ct) == 0 &&
-            (transform_info[i].bit_depths & bd) != 0 &&
+               (transform_info[i].bit_depths & bd) != 0 &&
-            (transform_info[i].when & TRANSFORM_R) != 0)
+               (transform_info[i].when & TRANSFORM_R) != 0)
-            active |= transform;
+               active |= transform;
 
-         else if ((transform_info[i].when & TRANSFORM_R) != 0)
+            else if ((transform_info[i].when & TRANSFORM_R) != 0)
-            inactive |= transform;
+               inactive |= transform;
+         }
       }
 
       /* Some transforms appear multiple times in the table; the 'active' status
@@ -904,9 +993,6 @@ update_display(struct display *dp)
 
       dp->active_transforms = active;
       dp->ignored_transforms = inactive; /* excluding write-only transforms */
-
-      if (active == 0)
-         display_log(dp, INTERNAL_ERROR, "bad transform table");
    }
 }
 
@@ -920,8 +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",\
@@ -946,7 +1033,7 @@ compare_read(struct display *dp, int applied_transforms)
    {
       unsigned long chunks =
          png_get_valid(dp->read_pp, dp->read_ip, 0xffffffff);
-      
+
       if (chunks != dp->chunks)
          display_log(dp, APP_FAIL, "PNG chunks changed from 0x%lx to 0x%lx",
             (unsigned long)dp->chunks, chunks);
@@ -1001,8 +1088,9 @@ 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)
-                  break;
+                  if (row[x] != orig[x])
+                     break;
 
                display_log(dp, APP_FAIL,
                   "byte(%lu,%lu) changed 0x%.2x -> 0x%.2x",
@@ -1013,6 +1101,7 @@ compare_read(struct display *dp, int applied_transforms)
       }
 
       else
+#     ifdef PNG_sBIT_SUPPORTED
       {
          unsigned long y;
          int bpp;   /* bits-per-pixel then bytes-per-pixel */
@@ -1056,6 +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;
          }
@@ -1089,8 +1179,8 @@ compare_read(struct display *dp, int applied_transforms)
          {
             int b;
 
-            case 16: /* Two bytes per component, bit-endian */
+            case 16: /* Two bytes per component, big-endian */
-               for (b = (bpp >> 4); b > 0; )
+               for (b = (bpp >> 4); b > 0; --b)
                {
                   unsigned int sig = (unsigned int)(0xffff0000 >> sig_bits[b]);
 
@@ -1117,7 +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;
@@ -1174,15 +1264,19 @@ compare_read(struct display *dp, int applied_transforms)
             }
          } /* for y */
       }
+#     else /* !sBIT */
+         display_log(dp, INTERNAL_ERROR,
+               "active shift transform but no sBIT support");
+#     endif /* !sBIT */
    }
 
    return 1; /* compare succeeded */
 }
 
-#ifdef PNG_WRITE_SUPPORTED
+#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.
     */
@@ -1226,7 +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);
 }
@@ -1278,7 +1372,7 @@ write_png(struct display *dp, png_infop ip, int transforms)
     */
    display_clean_write(dp);
 }
-#endif /* WRITE_SUPPORTED */
+#endif /* WRITE_PNG */
 
 static int
 skip_transform(struct display *dp, int tr)
@@ -1340,7 +1434,7 @@ test_one_file(struct display *dp, const char *filename)
          return; /* no point testing more */
    }
 
-#ifdef PNG_WRITE_SUPPORTED
+#ifdef PNG_WRITE_PNG_SUPPORTED
    /* Second test: write the original PNG data out to a new file (to test the
     * write side) then read the result back in and make sure that it hasn't
     * changed.
@@ -1361,7 +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 */
@@ -1381,7 +1475,7 @@ test_one_file(struct display *dp, const char *filename)
           * out and read it back in again (without the reversible transforms)
           * we should get back to the place where we started.
           */
-#ifdef PNG_WRITE_SUPPORTED
+#ifdef PNG_WRITE_PNG_SUPPORTED
          if ((current & write_transforms) == current)
          {
             /* All transforms reversible: write the PNG with the transformations
@@ -1487,7 +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;
@@ -1557,6 +1651,12 @@ main(const int argc, const char * const * const argv)
       else if (strcmp(name, "--nofind-bad-combos") == 0)
          d.options &= ~FIND_BAD_COMBOS;
 
+      else if (strcmp(name, "--list-combos") == 0)
+         d.options |= LIST_COMBOS;
+
+      else if (strcmp(name, "--nolist-combos") == 0)
+         d.options &= ~LIST_COMBOS;
+
       else if (name[0] == '-' && name[1] == '-')
       {
          fprintf(stderr, "pngimage: %s: unknown option\n", name);
@@ -1583,7 +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)
@@ -1595,8 +1695,9 @@ 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)
-                  printf("%s ", argv[j]);
+                  if (j != ilog)
+                     printf("%s ", argv[j]);
 
                printf("%s\n", d.filename);
             }
@@ -1605,14 +1706,17 @@ main(const int argc, const char * const * const argv)
          display_clean(&d);
       }
 
+      /* Release allocated memory */
+      display_destroy(&d);
+
       return errors != 0;
    }
 }
-#else /* !PNG_INFO_IMAGE_SUPPORTED || !PNG_READ_SUPPORTED */
+#else /* !READ_PNG */
 int
 main(void)
 {
    fprintf(stderr, "pngimage: no support for png_read/write_image\n");
-   return 77;
+   return SKIP;
 }
 #endif

contrib/libtests/pngstest-errors.h

@@ -0,0 +1,165 @@
+/* contrib/libtests/pngstest-errors.h
+ *
+ * BUILT USING: libpng version 1.6.19beta03 - September 25, 2015
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * THIS IS A MACHINE GENERATED FILE: do not edit it directly!
+ * Instead run:
+ *
+ *    pngstest --accumulate
+ *
+ * on as many PNG files as possible; at least PNGSuite and
+ * contrib/libtests/testpngs.
+ */
+static png_uint_16 gpc_error[16/*in*/][16/*out*/][4/*a*/] =
+{
+ { /* input: sRGB-gray */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 372, 0 }, { 0, 0, 372, 0 }, { 0, 0, 372, 0 }, { 0, 0, 372, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: sRGB-gray+alpha */
+  { 0, 19, 0, 0 }, { 0, 0, 0, 0 }, { 0, 20, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 897, 788, 0 }, { 0, 897, 788, 0 }, { 0, 897, 788, 0 }, { 0, 897, 788, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: sRGB-rgb */
+  { 0, 0, 19, 0 }, { 0, 0, 19, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 893, 0 }, { 0, 0, 893, 0 }, { 0, 0, 811, 0 }, { 0, 0, 811, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: sRGB-rgb+alpha */
+  { 0, 16, 17, 0 }, { 0, 17, 17, 0 }, { 0, 19, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 850, 875, 0 }, { 0, 850, 875, 0 }, { 0, 897, 788, 0 }, { 0, 897, 788, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: linear-gray */
+  { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: linear-gray+alpha */
+  { 0, 74, 9, 0 }, { 0, 20, 9, 0 }, { 0, 74, 9, 0 }, { 0, 20, 9, 0 },
+  { 0, 0, 0, 0 }, { 0, 1, 0, 0 }, { 0, 0, 0, 0 }, { 0, 1, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: linear-rgb */
+  { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 },
+  { 0, 0, 4, 0 }, { 0, 0, 4, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: linear-rgb+alpha */
+  { 0, 126, 143, 0 }, { 0, 11, 7, 0 }, { 0, 74, 9, 0 }, { 0, 17, 9, 0 },
+  { 0, 4, 4, 0 }, { 0, 5, 4, 0 }, { 0, 0, 0, 0 }, { 0, 1, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-sRGB-gray */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-sRGB-gray+alpha */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-sRGB-rgb */
+  { 0, 0, 13, 0 }, { 0, 0, 13, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 },
+  { 0, 0, 673, 0 }, { 0, 0, 673, 0 }, { 0, 0, 674, 0 }, { 0, 0, 674, 0 },
+  { 0, 0, 1, 0 }, { 0, 0, 1, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 460, 0 }, { 0, 0, 460, 0 }, { 0, 0, 263, 0 }, { 0, 0, 263, 0 }
+ }, { /* input: color-mapped-sRGB-rgb+alpha */
+  { 0, 6, 8, 0 }, { 0, 7, 8, 0 }, { 0, 75, 9, 0 }, { 0, 9, 9, 0 },
+  { 0, 585, 427, 0 }, { 0, 585, 427, 0 }, { 0, 717, 514, 0 }, { 0, 717, 514, 0 },
+  { 0, 1, 1, 0 }, { 0, 1, 1, 0 }, { 0, 1, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 13323, 460, 0 }, { 0, 427, 460, 0 }, { 0, 16480, 263, 0 }, { 0, 243, 263, 0 }
+ }, { /* input: color-mapped-linear-gray */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 282, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-linear-gray+alpha */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 253, 282, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-linear-rgb */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 265, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-linear-rgb+alpha */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 243, 265, 0 }
+ }
+};
+static png_uint_16 gpc_error_via_linear[16][4/*out*/][4] =
+{
+ { /* input: sRGB-gray */
+  { 0, 0, 7, 0 }, { 0, 0, 7, 0 }, { 0, 0, 7, 0 }, { 0, 0, 7, 0 }
+ }, { /* input: sRGB-gray+alpha */
+  { 0, 15, 15, 0 }, { 0, 186, 15, 0 }, { 0, 15, 15, 0 }, { 0, 186, 15, 0 }
+ }, { /* input: sRGB-rgb */
+  { 0, 0, 20, 0 }, { 0, 0, 20, 0 }, { 0, 0, 15, 0 }, { 0, 0, 15, 0 }
+ }, { /* input: sRGB-rgb+alpha */
+  { 0, 16, 17, 0 }, { 0, 187, 17, 0 }, { 0, 15, 15, 0 }, { 0, 186, 15, 0 }
+ }, { /* input: linear-gray */
+  { 0, 0, 1, 0 }, { 0, 0, 1, 0 }, { 0, 0, 1, 0 }, { 0, 0, 1, 0 }
+ }, { /* input: linear-gray+alpha */
+  { 0, 1, 1, 0 }, { 0, 1, 1, 0 }, { 0, 1, 1, 0 }, { 0, 1, 1, 0 }
+ }, { /* input: linear-rgb */
+  { 0, 0, 1, 0 }, { 0, 0, 1, 0 }, { 0, 0, 1, 0 }, { 0, 0, 1, 0 }
+ }, { /* input: linear-rgb+alpha */
+  { 0, 1, 1, 0 }, { 0, 9, 1, 0 }, { 0, 1, 1, 0 }, { 0, 1, 1, 0 }
+ }, { /* input: color-mapped-sRGB-gray */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-sRGB-gray+alpha */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-sRGB-rgb */
+  { 0, 0, 13, 0 }, { 0, 0, 13, 0 }, { 0, 0, 14, 0 }, { 0, 0, 14, 0 }
+ }, { /* input: color-mapped-sRGB-rgb+alpha */
+  { 0, 4, 8, 0 }, { 0, 9, 8, 0 }, { 0, 9, 5, 0 }, { 0, 32, 5, 0 }
+ }, { /* input: color-mapped-linear-gray */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-linear-gray+alpha */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-linear-rgb */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-linear-rgb+alpha */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }
+};
+static png_uint_16 gpc_error_to_colormap[8/*i*/][8/*o*/][4] =
+{
+ { /* input: sRGB-gray */
+  { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 },
+  { 0, 0, 560, 0 }, { 0, 0, 560, 0 }, { 0, 0, 560, 0 }, { 0, 0, 560, 0 }
+ }, { /* input: sRGB-gray+alpha */
+  { 0, 19, 9, 0 }, { 0, 255, 9, 25 }, { 0, 88, 9, 0 }, { 0, 255, 9, 25 },
+  { 0, 1012, 928, 0 }, { 0, 16026, 928, 6425 }, { 0, 1012, 928, 0 }, { 0, 16026, 928, 6425 }
+ }, { /* input: sRGB-rgb */
+  { 0, 0, 19, 0 }, { 0, 0, 19, 0 }, { 0, 0, 25, 0 }, { 0, 0, 25, 0 },
+  { 0, 0, 962, 0 }, { 0, 0, 962, 0 }, { 0, 0, 13677, 0 }, { 0, 0, 13677, 0 }
+ }, { /* input: sRGB-rgb+alpha */
+  { 0, 63, 77, 0 }, { 0, 255, 19, 25 }, { 0, 225, 25, 0 }, { 0, 255, 25, 67 },
+  { 0, 17534, 18491, 0 }, { 0, 15736, 2824, 6425 }, { 0, 14019, 13677, 0 }, { 0, 50115, 13677, 17219 }
+ }, { /* input: linear-gray */
+  { 0, 0, 73, 0 }, { 0, 0, 73, 0 }, { 0, 0, 73, 0 }, { 0, 0, 73, 0 },
+  { 0, 0, 18817, 0 }, { 0, 0, 18817, 0 }, { 0, 0, 18817, 0 }, { 0, 0, 18817, 0 }
+ }, { /* input: linear-gray+alpha */
+  { 0, 74, 74, 0 }, { 0, 255, 74, 25 }, { 0, 99, 74, 0 }, { 0, 255, 74, 25 },
+  { 0, 18919, 18907, 0 }, { 0, 24549, 18907, 6553 }, { 0, 18919, 18907, 0 }, { 0, 24549, 18907, 6553 }
+ }, { /* input: linear-rgb */
+  { 0, 0, 73, 0 }, { 0, 0, 73, 0 }, { 0, 0, 98, 0 }, { 0, 0, 98, 0 },
+  { 0, 0, 18664, 0 }, { 0, 0, 18664, 0 }, { 0, 0, 24998, 0 }, { 0, 0, 24998, 0 }
+ }, { /* input: linear-rgb+alpha */
+  { 0, 181, 196, 0 }, { 0, 255, 61, 25 }, { 206, 187, 98, 0 }, { 0, 255, 98, 67 },
+  { 0, 18141, 18137, 0 }, { 0, 17494, 17504, 6553 }, { 0, 24979, 24992, 0 }, { 0, 49172, 24992, 17347 }
+ }
+};
+/* END MACHINE GENERATED */

contrib/libtests/pngstest.c

@@ -1,9 +1,8 @@
-/*-
+
- * pngstest.c
+/* pngstest.c
  *
- * Copyright (c) 2013 John Cunningham Bowler
+ * Copyright (c) 2021 Cosmin Truta
- *
+ * Copyright (c) 2013-2017 John Cunningham Bowler
- * Last changed in libpng 1.6.8 [December 19, 2013]
  *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
@@ -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>
@@ -35,6 +35,15 @@
 #  include "../../png.h"
 #endif
 
+/* 1.6.1 added support for the configure test harness, which uses 77 to indicate
+ * a skipped test, in earlier versions we need to succeed on a skipped test, so:
+ */
+#if PNG_LIBPNG_VER >= 10601 && defined(HAVE_CONFIG_H)
+#  define SKIP 77
+#else
+#  define SKIP 0
+#endif
+
 #ifdef PNG_SIMPLIFIED_READ_SUPPORTED /* Else nothing can be done */
 #include "../tools/sRGB.h"
 
@@ -99,10 +108,18 @@ make_random_bytes(png_uint_32* seed, void* pv, size_t size)
    seed[1] = u1;
 }
 
+static png_uint_32 color_seed[2];
+
+static void
+reseed(void)
+{
+   color_seed[0] = 0x12345678U;
+   color_seed[1] = 0x9abcdefU;
+}
+
 static void
 random_color(png_colorp color)
 {
-   static png_uint_32 color_seed[2] = { 0x12345678, 0x9abcdef };
    make_random_bytes(color_seed, color, sizeof *color);
 }
 
@@ -307,7 +324,7 @@ compare_16bit(int v1, int v2, int error_limit, int multiple_algorithms)
 }
 #endif /* unused */
 
-#define READ_FILE 1      /* else memory */
+#define USE_FILE 1       /* else memory */
 #define USE_STDIO 2      /* else use file name */
 #define STRICT 4         /* fail on warnings too */
 #define VERBOSE 8
@@ -316,16 +333,19 @@ compare_16bit(int v1, int v2, int error_limit, int multiple_algorithms)
 #define ACCUMULATE 64
 #define FAST_WRITE 128
 #define sRGB_16BIT 256
+#define NO_RESEED  512   /* do not reseed on each new file */
+#define GBG_ERROR 1024   /* do not ignore the gamma+background_rgb_to_gray
+                          * libpng warning. */
 
 static void
 print_opts(png_uint_32 opts)
 {
-   if (opts & READ_FILE)
+   if (opts & USE_FILE)
       printf(" --file");
    if (opts & USE_STDIO)
       printf(" --stdio");
-   if (opts & STRICT)
+   if (!(opts & STRICT))
-      printf(" --strict");
+      printf(" --nostrict");
    if (opts & VERBOSE)
       printf(" --verbose");
    if (opts & KEEP_TMPFILES)
@@ -338,6 +358,12 @@ print_opts(png_uint_32 opts)
       printf(" --slow");
    if (opts & sRGB_16BIT)
       printf(" --sRGB-16bit");
+   if (opts & NO_RESEED)
+      printf(" --noreseed");
+#if PNG_LIBPNG_VER < 10700 /* else on by default */
+   if (opts & GBG_ERROR)
+      printf(" --fault-gbg-warning");
+#endif
 }
 
 #define FORMAT_NO_CHANGE 0x80000000 /* additional flag */
@@ -347,7 +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",
@@ -553,11 +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];
 }
@@ -615,7 +641,7 @@ freeimage(Image *image)
 
    if (image->tmpfile_name[0] != 0 && (image->opts & KEEP_TMPFILES) == 0)
    {
-      remove(image->tmpfile_name);
+      (void)remove(image->tmpfile_name);
       image->tmpfile_name[0] = 0;
    }
 }
@@ -640,7 +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)
    {
@@ -741,8 +767,15 @@ checkopaque(Image *image)
       return logerror(image, image->file_name, ": opaque not NULL", "");
    }
 
-   else if (image->image.warning_or_error != 0 && (image->opts & STRICT) != 0)
+   /* Separate out the gamma+background_rgb_to_gray warning because it may
-      return logerror(image, image->file_name, " --strict", "");
+    * produce opaque component errors:
+    */
+   else if (image->image.warning_or_error != 0 &&
+            (strcmp(image->image.message,
+               "libpng does not support gamma+background+rgb_to_gray") == 0 ?
+                  (image->opts & GBG_ERROR) != 0 : (image->opts & STRICT) != 0))
+      return logerror(image, image->file_name, (image->opts & GBG_ERROR) != 0 ?
+                      " --fault-gbg-warning" : " --strict", "");
 
    else
       return 1;
@@ -1110,7 +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
@@ -1118,7 +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:
@@ -1984,156 +2017,7 @@ static void (* const gpc_fn_colormapped[8/*in*/][8/*out*/])
  * gpc_error_to_colormap.
  */
 #if PNG_FORMAT_FLAG_COLORMAP == 8 /* extra check also required */
-/* START MACHINE GENERATED */
+#  include "pngstest-errors.h" /* machine generated */
-static png_uint_16 gpc_error[16/*in*/][16/*out*/][4/*a*/] =
-{
- { /* input: sRGB-gray */
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 372, 0 }, { 0, 0, 372, 0 }, { 0, 0, 372, 0 }, { 0, 0, 372, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
- }, { /* input: sRGB-gray+alpha */
-  { 0, 18, 0, 0 }, { 0, 0, 0, 0 }, { 0, 20, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 897, 788, 0 }, { 0, 897, 788, 0 }, { 0, 897, 788, 0 }, { 0, 897, 788, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
- }, { /* input: sRGB-rgb */
-  { 0, 0, 19, 0 }, { 0, 0, 19, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 893, 0 }, { 0, 0, 893, 0 }, { 0, 0, 811, 0 }, { 0, 0, 811, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
- }, { /* input: sRGB-rgb+alpha */
-  { 0, 4, 13, 0 }, { 0, 14, 13, 0 }, { 0, 19, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 832, 764, 0 }, { 0, 832, 764, 0 }, { 0, 897, 788, 0 }, { 0, 897, 788, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
- }, { /* input: linear-gray */
-  { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
- }, { /* input: linear-gray+alpha */
-  { 0, 74, 9, 0 }, { 0, 20, 9, 0 }, { 0, 74, 9, 0 }, { 0, 20, 9, 0 },
-  { 0, 0, 0, 0 }, { 0, 1, 0, 0 }, { 0, 0, 0, 0 }, { 0, 1, 0, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
- }, { /* input: linear-rgb */
-  { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 },
-  { 0, 0, 4, 0 }, { 0, 0, 4, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
- }, { /* input: linear-rgb+alpha */
-  { 0, 126, 143, 0 }, { 0, 9, 7, 0 }, { 0, 74, 9, 0 }, { 0, 16, 9, 0 },
-  { 0, 4, 4, 0 }, { 0, 5, 4, 0 }, { 0, 0, 0, 0 }, { 0, 1, 0, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
- }, { /* input: color-mapped-sRGB-gray */
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
- }, { /* input: color-mapped-sRGB-gray+alpha */
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
- }, { /* input: color-mapped-sRGB-rgb */
-  { 0, 0, 13, 0 }, { 0, 0, 13, 0 }, { 0, 0, 8, 0 }, { 0, 0, 8, 0 },
-  { 0, 0, 673, 0 }, { 0, 0, 673, 0 }, { 0, 0, 674, 0 }, { 0, 0, 674, 0 },
-  { 0, 0, 1, 0 }, { 0, 0, 1, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 460, 0 }, { 0, 0, 460, 0 }, { 0, 0, 263, 0 }, { 0, 0, 263, 0 }
- }, { /* input: color-mapped-sRGB-rgb+alpha */
-  { 0, 6, 8, 0 }, { 0, 7, 8, 0 }, { 0, 75, 8, 0 }, { 0, 9, 8, 0 },
-  { 0, 585, 427, 0 }, { 0, 585, 427, 0 }, { 0, 717, 409, 0 }, { 0, 717, 409, 0 },
-  { 0, 1, 1, 0 }, { 0, 1, 1, 0 }, { 0, 1, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 13323, 460, 0 }, { 0, 334, 460, 0 }, { 0, 16480, 263, 0 }, { 0, 243, 263, 0 }
- }, { /* input: color-mapped-linear-gray */
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 282, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
- }, { /* input: color-mapped-linear-gray+alpha */
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 0, 0 }, { 0, 253, 282, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
- }, { /* input: color-mapped-linear-rgb */
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 265, 0 }, { 0, 0, 0, 0 }
- }, { /* input: color-mapped-linear-rgb+alpha */
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 243, 265, 0 }
- }
-};
-static png_uint_16 gpc_error_via_linear[16][4/*out*/][4] =
-{
- { /* input: sRGB-gray */
-  { 0, 0, 7, 0 }, { 0, 0, 7, 0 }, { 0, 0, 7, 0 }, { 0, 0, 7, 0 }
- }, { /* input: sRGB-gray+alpha */
-  { 0, 15, 15, 0 }, { 0, 186, 15, 0 }, { 0, 15, 15, 0 }, { 0, 186, 15, 0 }
- }, { /* input: sRGB-rgb */
-  { 0, 0, 19, 0 }, { 0, 0, 19, 0 }, { 0, 0, 15, 0 }, { 0, 0, 15, 0 }
- }, { /* input: sRGB-rgb+alpha */
-  { 0, 12, 14, 0 }, { 0, 180, 14, 0 }, { 0, 14, 15, 0 }, { 0, 186, 15, 0 }
- }, { /* input: linear-gray */
-  { 0, 0, 1, 0 }, { 0, 0, 1, 0 }, { 0, 0, 1, 0 }, { 0, 0, 1, 0 }
- }, { /* input: linear-gray+alpha */
-  { 0, 1, 1, 0 }, { 0, 1, 1, 0 }, { 0, 1, 1, 0 }, { 0, 1, 1, 0 }
- }, { /* input: linear-rgb */
-  { 0, 0, 1, 0 }, { 0, 0, 1, 0 }, { 0, 0, 1, 0 }, { 0, 0, 1, 0 }
- }, { /* input: linear-rgb+alpha */
-  { 0, 1, 1, 0 }, { 0, 8, 1, 0 }, { 0, 1, 1, 0 }, { 0, 1, 1, 0 }
- }, { /* input: color-mapped-sRGB-gray */
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
- }, { /* input: color-mapped-sRGB-gray+alpha */
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
- }, { /* input: color-mapped-sRGB-rgb */
-  { 0, 0, 13, 0 }, { 0, 0, 13, 0 }, { 0, 0, 14, 0 }, { 0, 0, 14, 0 }
- }, { /* input: color-mapped-sRGB-rgb+alpha */
-  { 0, 4, 8, 0 }, { 0, 9, 8, 0 }, { 0, 8, 3, 0 }, { 0, 32, 3, 0 }
- }, { /* input: color-mapped-linear-gray */
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
- }, { /* input: color-mapped-linear-gray+alpha */
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
- }, { /* input: color-mapped-linear-rgb */
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
- }, { /* input: color-mapped-linear-rgb+alpha */
-  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
- }
-};
-static png_uint_16 gpc_error_to_colormap[8/*i*/][8/*o*/][4] =
-{
- { /* input: sRGB-gray */
-  { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 },
-  { 0, 0, 560, 0 }, { 0, 0, 560, 0 }, { 0, 0, 560, 0 }, { 0, 0, 560, 0 }
- }, { /* input: sRGB-gray+alpha */
-  { 0, 19, 2, 0 }, { 0, 255, 2, 25 }, { 0, 88, 2, 0 }, { 0, 255, 2, 25 },
-  { 0, 1012, 745, 0 }, { 0, 16026, 745, 6425 }, { 0, 1012, 745, 0 }, { 0, 16026, 745, 6425 }
- }, { /* input: sRGB-rgb */
-  { 0, 0, 19, 0 }, { 0, 0, 19, 0 }, { 0, 0, 25, 0 }, { 0, 0, 25, 0 },
-  { 0, 0, 937, 0 }, { 0, 0, 937, 0 }, { 0, 0, 13677, 0 }, { 0, 0, 13677, 0 }
- }, { /* input: sRGB-rgb+alpha */
-  { 0, 63, 77, 0 }, { 0, 255, 19, 25 }, { 0, 220, 25, 0 }, { 0, 255, 25, 67 },
-  { 0, 17534, 18491, 0 }, { 0, 15614, 2824, 6425 }, { 0, 14019, 13677, 0 }, { 0, 48573, 13677, 17219 }
- }, { /* input: linear-gray */
-  { 0, 0, 73, 0 }, { 0, 0, 73, 0 }, { 0, 0, 73, 0 }, { 0, 0, 73, 0 },
-  { 0, 0, 18817, 0 }, { 0, 0, 18817, 0 }, { 0, 0, 18817, 0 }, { 0, 0, 18817, 0 }
- }, { /* input: linear-gray+alpha */
-  { 0, 74, 74, 0 }, { 0, 255, 74, 25 }, { 0, 97, 74, 0 }, { 0, 255, 74, 25 },
-  { 0, 18919, 18907, 0 }, { 0, 24549, 18907, 6552 }, { 0, 18919, 18907, 0 }, { 0, 24549, 18907, 6552 }
- }, { /* input: linear-rgb */
-  { 0, 0, 73, 0 }, { 0, 0, 73, 0 }, { 0, 0, 98, 0 }, { 0, 0, 98, 0 },
-  { 0, 0, 18664, 0 }, { 0, 0, 18664, 0 }, { 0, 0, 24998, 0 }, { 0, 0, 24998, 0 }
- }, { /* input: linear-rgb+alpha */
-  { 0, 181, 196, 0 }, { 0, 255, 61, 25 }, { 206, 187, 98, 0 }, { 0, 255, 98, 67 },
-  { 0, 18141, 18137, 0 }, { 0, 17494, 17504, 6553 }, { 0, 24979, 24992, 0 }, { 0, 46509, 24992, 17347 }
- }
-};
-/* END MACHINE GENERATED */
 #endif /* COLORMAP flag check */
 #endif /* flag checks */
 
@@ -2153,8 +2037,8 @@ 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) */
+   int          output_8bit; /* Output is 8-bit (else 16-bit) */
 
    void (*in_gp)(Pixel*, png_const_voidp);
    void (*out_gp)(Pixel*, png_const_voidp);
@@ -2463,8 +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 = "";
@@ -2719,17 +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)
@@ -2818,7 +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);
@@ -2828,13 +2712,13 @@ compare_two_images(Image *a, Image *b, int via_linear,
 
             else if (y >= b->image.colormap_entries)
             {
-               if ((a->opts & ACCUMULATE) == 0)
+               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);
-                  }
+               }
                result = 0;
             }
 
@@ -2843,7 +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];
@@ -2862,22 +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);
          }
       }
@@ -2902,8 +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.
@@ -2933,8 +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)
-            btoa[bloc[i]] = aloc[i]; /* may be '4' for alpha */
+         {
+            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 */
@@ -2997,10 +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;
@@ -3016,10 +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;
@@ -3038,7 +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];
@@ -3157,14 +3054,14 @@ read_file(Image *image, png_uint_32 format, png_const_colorp background)
 static int
 read_one_file(Image *image)
 {
-   if (!(image->opts & READ_FILE) || (image->opts & USE_STDIO))
+   if (!(image->opts & USE_FILE) || (image->opts & USE_STDIO))
    {
       /* memory or stdio. */
       FILE *f = fopen(image->file_name, "rb");
 
       if (f != NULL)
       {
-         if (image->opts & READ_FILE)
+         if (image->opts & USE_FILE)
             image->input_file = f;
 
          else /* memory */
@@ -3173,32 +3070,45 @@ read_one_file(Image *image)
             {
                long int cb = ftell(f);
 
-               if (cb > 0 && (unsigned long int)cb < (size_t)~(size_t)0)
+               if (cb > 0)
                {
-                  png_bytep b = voidcast(png_bytep, malloc((size_t)cb));
+#ifndef __COVERITY__
-
+                  if ((unsigned long int)cb <= (size_t)~(size_t)0)
-                  if (b != NULL)
+#endif
                   {
-                     rewind(f);
+                     png_bytep b = voidcast(png_bytep, malloc((size_t)cb));
 
-                     if (fread(b, (size_t)cb, 1, f) == 1)
+                     if (b != NULL)
                      {
-                        fclose(f);
+                        rewind(f);
-                        image->input_memory_size = cb;
+
-                        image->input_memory = b;
+                        if (fread(b, (size_t)cb, 1, f) == 1)
+                        {
+                           fclose(f);
+                           image->input_memory_size = cb;
+                           image->input_memory = b;
+                        }
+
+                        else
+                        {
+                           free(b);
+                           return logclose(image, f, image->file_name,
+                              ": read failed: ");
+                        }
                      }
 
                      else
-                     {
-                        free(b);
                         return logclose(image, f, image->file_name,
-                           ": read failed: ");
+                           ": out of memory: ");
-                     }
                   }
 
                   else
                      return logclose(image, f, image->file_name,
-                        ": out of memory: ");
+                        ": file too big for this architecture: ");
+                     /* cb is the length of the file as a (long) and
+                      * this is greater than the maximum amount of
+                      * memory that can be requested from malloc.
+                      */
                }
 
                else if (cb == 0)
@@ -3232,7 +3142,41 @@ write_one_file(Image *output, Image *image, int convert_to_8bit)
 
    if (image->opts & USE_STDIO)
    {
+#ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
+#ifndef __COVERITY__
       FILE *f = tmpfile();
+#else
+      /* Experimental. Coverity says tmpfile() is insecure because it
+       * generates predictable names.
+       *
+       * It is possible to satisfy Coverity by using mkstemp(); however,
+       * any platform supporting mkstemp() undoubtedly has a secure tmpfile()
+       * implementation as well, and doesn't need the fix.  Note that
+       * the fix won't work on platforms that don't support mkstemp().
+       *
+       * https://www.securecoding.cert.org/confluence/display/c/
+       * FIO21-C.+Do+not+create+temporary+files+in+shared+directories
+       * says that most historic implementations of tmpfile() provide
+       * only a limited number of possible temporary file names
+       * (usually 26) before file names are recycled. That article also
+       * provides a secure solution that unfortunately depends upon mkstemp().
+       */
+      char tmpfile[] = "pngstest-XXXXXX";
+      int filedes;
+      FILE *f;
+      umask(0177);
+      filedes = mkstemp(tmpfile);
+      if (filedes < 0)
+        f = NULL;
+      else
+      {
+        f = fdopen(filedes,"w+");
+        /* Hide the filename immediately and ensure that the file does
+         * not exist after the program ends
+         */
+        (void) unlink(tmpfile);
+      }
+#endif
 
       if (f != NULL)
       {
@@ -3261,14 +3205,18 @@ write_one_file(Image *output, Image *image, int convert_to_8bit)
 
       else
          return logerror(image, "tmpfile", ": open: ", strerror(errno));
+#else /* SIMPLIFIED_WRITE_STDIO */
+      return logerror(image, "tmpfile", ": open: unsupported", "");
+#endif /* SIMPLIFIED_WRITE_STDIO */
    }
 
-   else
+   else if (image->opts & USE_FILE)
    {
-      static int counter = 0;
+#ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
+      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))
@@ -3284,6 +3232,51 @@ write_one_file(Image *output, Image *image, int convert_to_8bit)
 
       else
          return logerror(image, name, ": write failed", "");
+#else /* SIMPLIFIED_WRITE_STDIO */
+      return logerror(image, "stdio", ": open: unsupported", "");
+#endif /* SIMPLIFIED_WRITE_STDIO */
+   }
+
+   else /* use memory */
+   {
+      png_alloc_size_t size;
+
+      if (png_image_write_get_memory_size(image->image, size, convert_to_8bit,
+               image->buffer+16, (png_int_32)image->stride, image->colormap))
+      {
+         /* This is non-fatal but ignoring it was causing serious problems in
+          * the macro to be ignored:
+          */
+         if (size > PNG_IMAGE_PNG_SIZE_MAX(image->image))
+            return logerror(image, "memory", ": PNG_IMAGE_SIZE_MAX wrong", "");
+
+         initimage(output, image->opts, "memory", image->stride_extra);
+         output->input_memory = malloc(size);
+
+         if (output->input_memory != NULL)
+         {
+            output->input_memory_size = size;
+
+            if (png_image_write_to_memory(&image->image, output->input_memory,
+                  &output->input_memory_size, convert_to_8bit, image->buffer+16,
+                  (png_int_32)image->stride, image->colormap))
+            {
+               /* This is also non-fatal but it safes safer to error out anyway:
+                */
+               if (size != output->input_memory_size)
+                  return logerror(image, "memory", ": memory size wrong", "");
+            }
+
+            else
+               return logerror(image, "memory", ": write failed", "");
+         }
+
+         else
+            return logerror(image, "memory", ": out of memory", "");
+      }
+
+      else
+         return logerror(image, "memory", ": get size:", "");
    }
 
    /* 'output' has an initialized temporary image, read this back in and compare
@@ -3459,6 +3452,8 @@ test_one_file(const char *file_name, format_list *formats, png_uint_32 opts,
    int result;
    Image image;
 
+   if (!(opts & NO_RESEED))
+      reseed(); /* ensure that the random numbers don't depend on file order */
    newimage(&image);
    initimage(&image, opts, file_name, stride_extra);
    result = read_one_file(&image);
@@ -3496,7 +3491,7 @@ test_one_file(const char *file_name, format_list *formats, png_uint_32 opts,
 int
 main(int argc, char **argv)
 {
-   png_uint_32 opts = FAST_WRITE;
+   png_uint_32 opts = FAST_WRITE | STRICT;
    format_list formats;
    const char *touch = NULL;
    int log_pass = 0;
@@ -3505,11 +3500,17 @@ main(int argc, char **argv)
    int retval = 0;
    int c;
 
+#if PNG_LIBPNG_VER >= 10700
+      /* This error should not exist in 1.7 or later: */
+      opts |= GBG_ERROR;
+#endif
+
    init_sRGB_to_d();
 #if 0
    init_error_via_linear();
 #endif
    format_init(&formats);
+   reseed(); /* initialize random number seeds */
 
    for (c=1; c<argc; ++c)
    {
@@ -3524,17 +3525,17 @@ main(int argc, char **argv)
       }
       else if (strcmp(arg, "--file") == 0)
 #        ifdef PNG_STDIO_SUPPORTED
-            opts |= READ_FILE;
+            opts |= USE_FILE;
 #        else
-            return 77; /* skipped: no support */
+            return SKIP; /* skipped: no support */
 #        endif
       else if (strcmp(arg, "--memory") == 0)
-         opts &= ~READ_FILE;
+         opts &= ~USE_FILE;
       else if (strcmp(arg, "--stdio") == 0)
 #        ifdef PNG_STDIO_SUPPORTED
             opts |= USE_STDIO;
 #        else
-            return 77; /* skipped: no support */
+            return SKIP; /* skipped: no support */
 #        endif
       else if (strcmp(arg, "--name") == 0)
          opts &= ~USE_STDIO;
@@ -3560,10 +3561,16 @@ main(int argc, char **argv)
          opts &= ~KEEP_GOING;
       else if (strcmp(arg, "--strict") == 0)
          opts |= STRICT;
+      else if (strcmp(arg, "--nostrict") == 0)
+         opts &= ~STRICT;
       else if (strcmp(arg, "--sRGB-16bit") == 0)
          opts |= sRGB_16BIT;
       else if (strcmp(arg, "--linear-16bit") == 0)
          opts &= ~sRGB_16BIT;
+      else if (strcmp(arg, "--noreseed") == 0)
+         opts |= NO_RESEED;
+      else if (strcmp(arg, "--fault-gbg-warning") == 0)
+         opts |= GBG_ERROR;
       else if (strcmp(arg, "--tmpfile") == 0)
       {
          if (c+1 < argc)
@@ -3577,7 +3584,7 @@ main(int argc, char **argv)
             }
 
             /* Safe: checked above */
-            strcpy(tmpf, argv[c]);
+            strncpy(tmpf, argv[c], sizeof (tmpf)-1);
          }
 
          else
@@ -3623,7 +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
@@ -3676,6 +3683,23 @@ main(int argc, char **argv)
    {
       unsigned int in;
 
+      printf("/* contrib/libtests/pngstest-errors.h\n");
+      printf(" *\n");
+      printf(" * BUILT USING:" PNG_HEADER_VERSION_STRING);
+      printf(" *\n");
+      printf(" * This code is released under the libpng license.\n");
+      printf(" * For conditions of distribution and use, see the disclaimer\n");
+      printf(" * and license in png.h\n");
+      printf(" *\n");
+      printf(" * THIS IS A MACHINE GENERATED FILE: do not edit it directly!\n");
+      printf(" * Instead run:\n");
+      printf(" *\n");
+      printf(" *    pngstest --accumulate\n");
+      printf(" *\n");
+      printf(" * on as many PNG files as possible; at least PNGSuite and\n");
+      printf(" * contrib/libtests/testpngs.\n");
+      printf(" */\n");
+
       printf("static png_uint_16 gpc_error[16/*in*/][16/*out*/][4/*a*/] =\n");
       printf("{\n");
       for (in=0; in<16; ++in)
@@ -3765,6 +3789,7 @@ main(int argc, char **argv)
             putchar('\n');
       }
       printf("};\n");
+      printf("/* END MACHINE GENERATED */\n");
    }
 
    if (retval == 0 && touch != NULL)
@@ -3802,6 +3827,6 @@ int main(void)
 {
    fprintf(stderr, "pngstest: no read support in libpng, test skipped\n");
    /* So the test is skipped: */
-   return 77;
+   return SKIP;
 }
 #endif /* PNG_SIMPLIFIED_READ_SUPPORTED */

contrib/libtests/pngunknown.c

@@ -1,8 +1,8 @@
 
 /* pngunknown.c - test the read side unknown chunk handling
  *
- * Last changed in libpng 1.6.10 [March 6, 2014]
+ * Copyright (c) 2021 Cosmin Truta
- * Copyright (c) 2014 Glenn Randers-Pehrson
+ * Copyright (c) 2015,2017 Glenn Randers-Pehrson
  * Written by John Cunningham Bowler
  *
  * This code is released under the libpng license.
@@ -30,10 +30,21 @@
 #  include "../../png.h"
 #endif
 
+/* 1.6.1 added support for the configure test harness, which uses 77 to indicate
+ * a skipped test, in earlier versions we need to succeed on a skipped test, so:
+ */
+#if PNG_LIBPNG_VER >= 10601 && defined(HAVE_CONFIG_H)
+#  define SKIP 77
+#else
+#  define SKIP 0
+#endif
+
+
 /* Since this program tests the ability to change the unknown chunk handling
  * these must be defined:
  */
 #if defined(PNG_SET_UNKNOWN_CHUNKS_SUPPORTED) &&\
+   defined(PNG_STDIO_SUPPORTED) &&\
    defined(PNG_READ_SUPPORTED)
 
 /* One of these must be defined to allow us to find out what happened.  It is
@@ -45,7 +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: */
@@ -74,7 +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))
@@ -103,6 +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)
@@ -199,6 +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,
@@ -351,7 +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);
@@ -363,7 +384,7 @@ ancillary(const char *name)
    return PNG_CHUNK_ANCILLARY(PNG_U32(name[0], name[1], name[2], name[3]));
 }
 
-#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+#ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
 static int
 ancillaryb(const png_byte *name)
 {
@@ -467,7 +488,7 @@ get_valid(display *d, png_infop info_ptr)
       png_textp text;
       png_uint_32 ntext = png_get_text(d->png_ptr, info_ptr, &text, NULL);
 
-      while (ntext-- > 0) switch (text[ntext].compression)
+      while (ntext > 0) switch (text[--ntext].compression)
       {
          case -1:
             flags |= PNG_INFO_tEXt;
@@ -528,33 +549,36 @@ 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)
    {
-      png_uint_32 flag = chunk_info[chunk].flag;
+      if (!discard) /* stupidity to stop a GCC warning */
+      {
+         png_uint_32 flag = chunk_info[chunk].flag;
 
-      if (pc->location & PNG_AFTER_IDAT)
+         if (pc->location & PNG_AFTER_IDAT)
-         d->after_IDAT |= flag;
+            d->after_IDAT |= flag;
 
-      else
+         else
-         d->before_IDAT |= flag;
+            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.
     */
-#  ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+#  ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
       return discard;
 #  else
       return 1; /*handled; discard*/
@@ -562,7 +586,7 @@ read_callback(png_structp pp, png_unknown_chunkp pc)
 }
 #endif /* READ_USER_CHUNKS_SUPPORTED */
 
-#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+#ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
 static png_uint_32
 get_unknown(display *d, png_infop info_ptr, int after_IDAT)
 {
@@ -603,7 +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;
          }
@@ -615,7 +639,7 @@ get_unknown(display *d, png_infop info_ptr, int after_IDAT)
 
    return flags;
 }
-#else
+#else /* SAVE_UNKNOWN_CHUNKS */
 static png_uint_32
 get_unknown(display *d, png_infop info_ptr, int after_IDAT)
    /* Otherwise this will return the cached values set by any user callback */
@@ -634,8 +658,8 @@ get_unknown(display *d, png_infop info_ptr, int after_IDAT)
        * a check to ensure the logic is correct.
        */
 #     error No store support and no user chunk support, this will not work
-#  endif
+#  endif /* READ_USER_CHUNKS */
-#endif
+#endif /* SAVE_UNKNOWN_CHUNKS */
 
 static int
 check(FILE *fp, int argc, const char **argv, png_uint_32p flags/*out*/,
@@ -722,11 +746,17 @@ check(FILE *fp, int argc, const char **argv, png_uint_32p flags/*out*/,
                    * in this case, so we just check the arguments!  This could
                    * be improved in the future by using the read callback.
                    */
-                  png_byte name[5];
+#                 if PNG_LIBPNG_VER >= 10700 &&\
+                     !defined(PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED)
+                     if (option < PNG_HANDLE_CHUNK_IF_SAFE)
+#                 endif /* 1.7+ SAVE_UNKNOWN_CHUNKS */
+                  {
+                     png_byte name[5];
 
-                  memcpy(name, chunk_info[chunk].name, 5);
+                     memcpy(name, chunk_info[chunk].name, 5);
-                  png_set_keep_unknown_chunks(d->png_ptr, option, name, 1);
+                     png_set_keep_unknown_chunks(d->png_ptr, option, name, 1);
-                  chunk_info[chunk].keep = option;
+                     chunk_info[chunk].keep = option;
+                  }
                   continue;
                }
 
@@ -735,7 +765,12 @@ check(FILE *fp, int argc, const char **argv, png_uint_32p flags/*out*/,
             case 7: /* default */
                if (memcmp(argv[i], "default", 7) == 0)
                {
-                  png_set_keep_unknown_chunks(d->png_ptr, option, NULL, 0);
+#                 if PNG_LIBPNG_VER >= 10700 &&\
+                     !defined(PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED)
+                     if (option < PNG_HANDLE_CHUNK_IF_SAFE)
+#                 endif /* 1.7+ SAVE_UNKNOWN_CHUNKS */
+                     png_set_keep_unknown_chunks(d->png_ptr, option, NULL, 0);
+
                   d->keep = option;
                   continue;
                }
@@ -745,7 +780,12 @@ check(FILE *fp, int argc, const char **argv, png_uint_32p flags/*out*/,
             case 3: /* all */
                if (memcmp(argv[i], "all", 3) == 0)
                {
-                  png_set_keep_unknown_chunks(d->png_ptr, option, NULL, -1);
+#                 if PNG_LIBPNG_VER >= 10700 &&\
+                     !defined(PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED)
+                     if (option < PNG_HANDLE_CHUNK_IF_SAFE)
+#                 endif /* 1.7+ SAVE_UNKNOWN_CHUNKS */
+                     png_set_keep_unknown_chunks(d->png_ptr, option, NULL, -1);
+
                   d->keep = option;
 
                   for (chunk = 0; chunk < NINFO; ++chunk)
@@ -806,8 +846,9 @@ 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)
-                  png_read_row(d->png_ptr, NULL, NULL);
+                  if (PNG_ROW_IN_INTERLACE_PASS(y, ipass))
+                     png_read_row(d->png_ptr, NULL, NULL);
             }
          }
       } /* interlaced */
@@ -985,6 +1026,20 @@ perform_one_test(FILE *fp, int argc, const char **argv,
 
    def = check(fp, argc, argv, flags[1], d, set_callback);
 
+   /* If IDAT is being handled as unknown the image read is skipped and all the
+    * IDATs after the first end up in the end info struct, so in this case add
+    * IDAT to the list of unknowns.  (Do this after 'check' above sets the
+    * chunk_info 'keep' fields.)
+    *
+    * Note that the flag setting has to be in the 'known' field to avoid
+    * triggering the consistency check below and the flag must only be set if
+    * there are multiple IDATs, so if the check above did find an unknown IDAT
+    * after IDAT.
+    */
+   if (chunk_info[0/*IDAT*/].keep != PNG_HANDLE_CHUNK_AS_DEFAULT &&
+       (flags[1][3] & PNG_INFO_IDAT) != 0)
+      flags[0][2] |= PNG_INFO_IDAT;
+
    /* Chunks should either be known or unknown, never both and this should apply
     * whether the chunk is before or after the IDAT (actually, the app can
     * probably change this by swapping the handling after the image, but this
@@ -1042,15 +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",
+   "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
@@ -1066,7 +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;
@@ -1104,8 +1159,9 @@ 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)
-      usage(d.program, "extra arguments");
+      if (argc != 1)
+         usage(d.program, "extra arguments");
 
    /* The name of the test file is the last argument; remove it. */
    d.file = argv[--argc];
@@ -1167,7 +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);
@@ -1229,7 +1289,7 @@ main(void)
    fprintf(stderr,
       " test ignored: no support to find out about unknown chunks\n");
    /* So the test is skipped: */
-   return 77;
+   return SKIP;
 }
 #endif /* READ_USER_CHUNKS || SAVE_UNKNOWN_CHUNKS */
 
@@ -1240,6 +1300,6 @@ main(void)
    fprintf(stderr,
       " test ignored: no support to modify unknown chunk handling\n");
    /* So the test is skipped: */
-   return 77;
+   return SKIP;
 }
 #endif /* SET_UNKNOWN_CHUNKS && READ*/

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
@@ -60,8 +59,9 @@ 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);
       display = malloc(rowbytes);
 
@@ -70,7 +70,12 @@ read_png(FILE *fp)
 
       {
          png_uint_32 height = png_get_image_height(png_ptr, info_ptr);
-         int passes = png_set_interlace_handling(png_ptr);
+#        ifdef PNG_READ_INTERLACING_SUPPORTED
+            int passes = png_set_interlace_handling(png_ptr);
+#        else /* !READ_INTERLACING */
+            int passes = png_get_interlace_type(png_ptr, info_ptr) ==
+               PNG_INTERLACE_ADAM7 ? PNG_INTERLACE_ADAM7_PASSES : 1;
+#        endif /* !READ_INTERLACING */
          int pass;
 
          png_start_read_image(png_ptr);
@@ -79,6 +84,11 @@ read_png(FILE *fp)
          {
             png_uint_32 y = height;
 
+#           ifndef PNG_READ_INTERLACING_SUPPORTED
+               if (passes == PNG_INTERLACE_ADAM7_PASSES)
+                  y = PNG_PASS_ROWS(y, pass);
+#           endif /* READ_INTERLACING */
+
             /* NOTE: this trashes the row each time; interlace handling won't
              * work, but this avoids memory thrashing for speed testing.
              */

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;
       }
 
@@ -521,10 +523,13 @@ 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)
    {
-      if (!check_one_character(co, c, ch))
+      for (ch=0; ch<256; ++ch)
-         return 0;
+      {
+         if (!check_one_character(co, c, ch))
+            return 0;
+      }
    }
 
    return 1;
@@ -539,10 +544,13 @@ 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)
       {
-         if (!check_one_character(co, c, tests[i]))
+         for (i=0; tests[i]; ++i)
-               return 0;
+         {
+            if (!check_one_character(co, c, tests[i]))
+                  return 0;
+         }
       }
 
       /* At the end check all the characters. */
@@ -616,10 +624,10 @@ int validation_muldiv(int count, int argc, char **argv)
    png_int_32 times, div;
 
    while (--argc > 0)
-      {
+   {
-         fprintf(stderr, "unknown argument %s\n", *++argv);
+      fprintf(stderr, "unknown argument %s\n", *++argv);
-         return 1;
+      return 1;
-      }
+   }
 
    /* Find out about the random number generator. */
    randbuffer = RAND_MAX;
@@ -634,7 +642,7 @@ int validation_muldiv(int count, int argc, char **argv)
    {
       png_fixed_point result;
       /* NOTE: your mileage may vary, a type is required below that can
-       * hold 64 bits or more, if floating point is used a 64 bit or
+       * hold 64 bits or more, if floating point is used a 64-bit or
        * better mantissa is required.
        */
       long long int fp, fpround;
@@ -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;
 }
 
@@ -799,13 +807,13 @@ int validation_gamma(int argc, char **argv)
          if (i == 0 && png_log8bit(i) != 0xffffffff ||
              i != 0 && png_log8bit(i) != floor(correct+.5))
          {
-            fprintf(stderr, "8 bit log error: %d: got %u, expected %f\n",
+            fprintf(stderr, "8-bit log error: %d: got %u, expected %f\n",
                i, png_log8bit(i), correct);
          }
       }
 
       if (!silent)
-         printf("maximum 8 bit log error = %f\n", maxerr);
+         printf("maximum 8-bit log error = %f\n", maxerr);
 
       maxerr = 0;
       for (i=0; i<65536; ++i)
@@ -821,14 +829,15 @@ 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);
             }
          }
       }
 
       if (!silent)
-         printf("maximum 16 bit log error = %f\n", maxerr);
+         printf("maximum 16-bit log error = %f\n", maxerr);
 
       /* Now exponentiations. */
       maxerr = 0;
@@ -841,13 +850,14 @@ 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);
          }
       }
 
       if (!silent)
-         printf("maximum 32 bit exp error = %f\n", maxerr);
+         printf("maximum 32-bit exp error = %f\n", maxerr);
 
       maxerr = 0;
       for (i=0; i<=0xfffff; ++i)
@@ -859,13 +869,14 @@ 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);
          }
       }
 
       if (!silent)
-         printf("maximum 8 bit exp error = %f\n", maxerr);
+         printf("maximum 8-bit exp error = %f\n", maxerr);
 
       maxerr = 0;
       for (i=0; i<=0xfffff; ++i)
@@ -877,13 +888,14 @@ 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);
          }
       }
 
       if (!silent)
-         printf("maximum 16 bit exp error = %f\n", maxerr);
+         printf("maximum 16-bit exp error = %f\n", maxerr);
    } /* !onlygamma */
 
    /* Test the overall gamma correction. */
@@ -913,7 +925,7 @@ int validation_gamma(int argc, char **argv)
       }
 
       if (!silent)
-         printf("gamma %f: maximum 8 bit error %f\n", g, maxerr);
+         printf("gamma %f: maximum 8-bit error %f\n", g, maxerr);
 
       maxerr = 0;
       for (j=0; j<65536; ++j)
@@ -932,7 +944,7 @@ int validation_gamma(int argc, char **argv)
       }
 
       if (!silent)
-         printf("gamma %f: maximum 16 bit error %f\n", g, maxerr);
+         printf("gamma %f: maximum 16-bit error %f\n", g, maxerr);
    }
 
    return 0;
@@ -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

@@ -1,8 +1,7 @@
+
 /* timepng.c
  *
- * Copyright (c) 2013 John Cunningham Bowler
+ * Copyright (c) 2013,2016 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
@@ -10,15 +9,17 @@
  *
  * Load an arbitrary number of PNG files (from the command line, or, if there
  * are no arguments on the command line, from stdin) then run a time test by
- * reading each file by row.  The test does nothing with the read result and
+ * reading each file by row or by image (possibly with transforms in the latter
- * does no transforms.  The only output is a time as a floating point number of
+ * case).  The only output is a time as a floating point number of seconds with
- * seconds with 9 decimal digits.
+ * 9 decimal digits.
  */
 #define _POSIX_C_SOURCE 199309L /* for clock_gettime */
 
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
+#include <errno.h>
+#include <limits.h>
 
 #include <time.h>
 
@@ -35,36 +36,73 @@
 #  include "../../png.h"
 #endif
 
-static int read_png(FILE *fp)
+/* The following is to support direct compilation of this file as C++ */
+#ifdef __cplusplus
+#  define voidcast(type, value) static_cast<type>(value)
+#else
+#  define voidcast(type, value) (value)
+#endif /* __cplusplus */
+
+/* 'CLOCK_PROCESS_CPUTIME_ID' is one of the clock timers for clock_gettime.  It
+ * need not be supported even when clock_gettime is available.  It returns the
+ * 'CPU' time the process has consumed.  'CPU' time is assumed to include time
+ * when the CPU is actually blocked by a pending cache fill but not time
+ * waiting for page faults.  The attempt is to get a measure of the actual time
+ * the implementation takes to read a PNG ignoring the potentially very large IO
+ * overhead.
+ */
+#if defined (CLOCK_PROCESS_CPUTIME_ID) && defined(PNG_STDIO_SUPPORTED) &&\
+    defined(PNG_EASY_ACCESS_SUPPORTED) &&\
+    (PNG_LIBPNG_VER >= 10700 ? defined(PNG_READ_PNG_SUPPORTED) :\
+     defined (PNG_SEQUENTIAL_READ_SUPPORTED) &&\
+     defined(PNG_INFO_IMAGE_SUPPORTED))
+
+typedef struct
 {
-   png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,0,0,0);
+   FILE *input;
-   png_infop info_ptr = NULL;
+   FILE *output;
-   png_bytep row = NULL, display = NULL;
+}  io_data;
 
-   if (png_ptr == NULL)
+static PNG_CALLBACK(void, read_and_copy,
-      return 0;
+      (png_structp png_ptr, png_bytep buffer, size_t cb))
+{
+   io_data *io = (io_data*)png_get_io_ptr(png_ptr);
 
-   if (setjmp(png_jmpbuf(png_ptr)))
+   if (fread(buffer, cb, 1, io->input) != 1)
+      png_error(png_ptr, strerror(errno));
+
+   if (fwrite(buffer, cb, 1, io->output) != 1)
    {
-      png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+      perror("temporary file");
-      if (row != NULL) free(row);
+      fprintf(stderr, "temporary file PNG write failed\n");
-      if (display != NULL) free(display);
+      exit(1);
-      return 0;
    }
+}
 
-   png_init_io(png_ptr, fp);
+static void read_by_row(png_structp png_ptr, png_infop info_ptr,
+      FILE *write_ptr, FILE *read_ptr)
+{
+   /* These don't get freed on error, this is fine; the program immediately
+    * exits.
+    */
+   png_bytep row = NULL, display = NULL;
+   io_data io_copy;
 
-   info_ptr = png_create_info_struct(png_ptr);
+   if (write_ptr != NULL)
-   if (info_ptr == NULL)
+   {
-      png_error(png_ptr, "OOM allocating info structure");
+      /* Set up for a copy to the temporary file: */
+      io_copy.input = read_ptr;
+      io_copy.output = write_ptr;
+      png_set_read_fn(png_ptr, &io_copy, read_and_copy);
+   }
 
    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 = malloc(rowbytes);
+      row = voidcast(png_bytep,malloc(rowbytes));
-      display = malloc(rowbytes);
+      display = voidcast(png_bytep,malloc(rowbytes));
 
       if (row == NULL || display == NULL)
          png_error(png_ptr, "OOM allocating row buffers");
@@ -81,7 +119,8 @@ static int read_png(FILE *fp)
             png_uint_32 y = height;
 
             /* NOTE: this trashes the row each time; interlace handling won't
-             * work, but this avoids memory thrashing for speed testing.
+             * work, but this avoids memory thrashing for speed testing and is
+             * somewhat representative of an application that works row-by-row.
              */
             while (y-- > 0)
                png_read_row(png_ptr, row, display);
@@ -91,9 +130,51 @@ static int read_png(FILE *fp)
 
    /* Make sure to read to the end of the file: */
    png_read_end(png_ptr, info_ptr);
-   png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+
+   /* Free this up: */
    free(row);
    free(display);
+}
+
+static PNG_CALLBACK(void, no_warnings, (png_structp png_ptr,
+         png_const_charp warning))
+{
+   (void)png_ptr;
+   (void)warning;
+}
+
+static int read_png(FILE *fp, png_int_32 transforms, FILE *write_file)
+{
+   png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,0,0,
+         no_warnings);
+   png_infop info_ptr = NULL;
+
+   if (png_ptr == NULL)
+      return 0;
+
+   if (setjmp(png_jmpbuf(png_ptr)))
+   {
+      png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+      return 0;
+   }
+
+#  ifdef PNG_BENIGN_ERRORS_SUPPORTED
+      png_set_benign_errors(png_ptr, 1/*allowed*/);
+#  endif
+   png_init_io(png_ptr, fp);
+
+   info_ptr = png_create_info_struct(png_ptr);
+
+   if (info_ptr == NULL)
+      png_error(png_ptr, "OOM allocating info structure");
+
+   if (transforms < 0)
+      read_by_row(png_ptr, info_ptr, write_file, fp);
+
+   else
+      png_read_png(png_ptr, info_ptr, transforms, NULL/*params*/);
+
+   png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
    return 1;
 }
 
@@ -108,7 +189,7 @@ static int mytime(struct timespec *t)
    return 0;
 }
 
-static int perform_one_test(FILE *fp, int nfiles)
+static int perform_one_test(FILE *fp, int nfiles, png_int_32 transforms)
 {
    int i;
    struct timespec before, after;
@@ -120,7 +201,7 @@ static int perform_one_test(FILE *fp, int nfiles)
    {
       for (i=0; i<nfiles; ++i)
       {
-         if (read_png(fp))
+         if (read_png(fp, transforms, NULL/*write*/))
          {
             if (ferror(fp))
             {
@@ -184,120 +265,343 @@ static int add_one_file(FILE *fp, char *name)
 
    if (ip != NULL)
    {
-      int ch;
+      /* Read the file using libpng; this detects errors and also deals with
-      for (;;)
+       * files which contain data beyond the end of the file.
+       */
+      int ok = 0;
+      fpos_t pos;
+
+      if (fgetpos(fp, &pos))
       {
-         ch = getc(ip);
+         /* Fatal error reading the start: */
-         if (ch == EOF) break;
+         perror("temporary file");
-         putc(ch, fp);
+         fprintf(stderr, "temporary file fgetpos error\n");
+         exit(1);
       }
 
-      if (ferror(ip))
+      if (read_png(ip, -1/*by row*/, fp/*output*/))
       {
-         perror(name);
+         if (ferror(ip))
-         fprintf(stderr, "%s: read error\n", name);
+         {
-         return 0;
+            perror(name);
+            fprintf(stderr, "%s: read error\n", name);
+         }
+
+         else
+            ok = 1; /* read ok */
       }
 
+      else
+         fprintf(stderr, "%s: file not added\n", name);
+
       (void)fclose(ip);
 
+      /* An error in the output is fatal; exit immediately: */
       if (ferror(fp))
       {
          perror("temporary file");
          fprintf(stderr, "temporary file write error\n");
-         return 0;
+         exit(1);
+      }
+
+      if (ok)
+         return 1;
+
+      /* Did not read the file successfully, simply rewind the temporary
+       * file.  This must happen after the ferror check above to avoid clearing
+       * the error.
+       */
+      if (fsetpos(fp, &pos))
+      {
+         perror("temporary file");
+         fprintf(stderr, "temporary file fsetpos error\n");
+         exit(1);
       }
    }
 
    else
    {
+      /* file open error: */
       perror(name);
       fprintf(stderr, "%s: open failed\n", name);
-      return 0;
    }
 
-   return 1;
+   return 0; /* file not added */
+}
+
+static void
+usage(FILE *fp)
+{
+   if (fp != NULL) fclose(fp);
+
+   fprintf(stderr,
+"Usage:\n"
+" timepng --assemble <assembly> {files}\n"
+"  Read the files into <assembly>, output the count.  Options are ignored.\n"
+" timepng --dissemble <assembly> <count> [options]\n"
+"  Time <count> files from <assembly>, additional files may not be given.\n"
+" Otherwise:\n"
+"  Read the files into a temporary file and time the decode\n"
+"Transforms:\n"
+"  --by-image: read by image with png_read_png\n"
+"  --<transform>: implies by-image, use PNG_TRANSFORM_<transform>\n"
+"  Otherwise: read by row using png_read_row (to a single row buffer)\n"
+   /* ISO C90 string length max 509 */);fprintf(stderr,
+"{files}:\n"
+"  PNG files to copy into the assembly and time.  Invalid files are skipped\n"
+"  with appropriate error messages.  If no files are given the list of files\n"
+"  is read from stdin with each file name terminated by a newline\n"
+"Output:\n"
+"  For --assemble the output is the name of the assembly file followed by the\n"
+"  count of the files it contains; the arguments for --dissemble.  Otherwise\n"
+"  the output is the total decode time in seconds.\n");
+
+   exit(99);
 }
 
 int main(int argc, char **argv)
 {
    int ok = 0;
-   FILE *fp = tmpfile();
+   int err = 0;
+   int nfiles = 0;
+   int transforms = -1; /* by row */
+   const char *assembly = NULL;
+   FILE *fp;
 
-   if (fp != NULL)
+   if (argc > 2 && strcmp(argv[1], "--assemble") == 0)
    {
-      int err = 0;
+      /* Just build the test file, argv[2] is the file name. */
-      int nfiles = 0;
+      assembly = argv[2];
-
+      fp = fopen(assembly, "wb");
-      if (argc > 1)
+      if (fp == NULL)
       {
-         int i;
+         perror(assembly);
+         fprintf(stderr, "timepng --assemble %s: could not open for write\n",
+               assembly);
+         usage(NULL);
+      }
 
-         for (i=1; i<argc; ++i)
+      argv += 2;
+      argc -= 2;
+   }
+
+   else if (argc > 3 && strcmp(argv[1], "--dissemble") == 0)
+   {
+      fp = fopen(argv[2], "rb");
+
+      if (fp == NULL)
+      {
+         perror(argv[2]);
+         fprintf(stderr, "timepng --dissemble %s: could not open for read\n",
+               argv[2]);
+         usage(NULL);
+      }
+
+      nfiles = atoi(argv[3]);
+      if (nfiles <= 0)
+      {
+         fprintf(stderr,
+               "timepng --dissemble <file> <count>: %s is not a count\n",
+               argv[3]);
+         exit(99);
+      }
+#ifdef __COVERITY__
+      else
+      {
+         nfiles &= PNG_UINT_31_MAX;
+      }
+#endif
+
+      argv += 3;
+      argc -= 3;
+   }
+
+   else /* Else use a temporary file */
+   {
+#ifndef __COVERITY__
+      fp = tmpfile();
+#else
+      /* Experimental. Coverity says tmpfile() is insecure because it
+       * generates predictable names.
+       *
+       * It is possible to satisfy Coverity by using mkstemp(); however,
+       * any platform supporting mkstemp() undoubtedly has a secure tmpfile()
+       * implementation as well, and doesn't need the fix.  Note that
+       * the fix won't work on platforms that don't support mkstemp().
+       *
+       * https://www.securecoding.cert.org/confluence/display/c/
+       * FIO21-C.+Do+not+create+temporary+files+in+shared+directories
+       * says that most historic implementations of tmpfile() provide
+       * only a limited number of possible temporary file names
+       * (usually 26) before file names are recycled. That article also
+       * provides a secure solution that unfortunately depends upon mkstemp().
+       */
+      char tmpfile[] = "timepng-XXXXXX";
+      int filedes;
+      umask(0177);
+      filedes = mkstemp(tmpfile);
+      if (filedes < 0)
+        fp = NULL;
+      else
+      {
+        fp = fdopen(filedes,"w+");
+        /* Hide the filename immediately and ensure that the file does
+         * not exist after the program ends
+         */
+        (void) unlink(tmpfile);
+      }
+#endif
+
+      if (fp == NULL)
+      {
+         perror("tmpfile");
+         fprintf(stderr, "timepng: could not open the temporary file\n");
+         exit(1); /* not a user error */
+      }
+   }
+
+   /* Handle the transforms: */
+   while (argc > 1 && argv[1][0] == '-' && argv[1][1] == '-')
+   {
+      const char *opt = *++argv + 2;
+
+      --argc;
+
+      /* Transforms turn on the by-image processing and maybe set some
+       * transforms:
+       */
+      if (transforms == -1)
+         transforms = PNG_TRANSFORM_IDENTITY;
+
+      if (strcmp(opt, "by-image") == 0)
+      {
+         /* handled above */
+      }
+
+#        define OPT(name) else if (strcmp(opt, #name) == 0)\
+         transforms |= PNG_TRANSFORM_ ## name
+
+      OPT(STRIP_16);
+      OPT(STRIP_ALPHA);
+      OPT(PACKING);
+      OPT(PACKSWAP);
+      OPT(EXPAND);
+      OPT(INVERT_MONO);
+      OPT(SHIFT);
+      OPT(BGR);
+      OPT(SWAP_ALPHA);
+      OPT(SWAP_ENDIAN);
+      OPT(INVERT_ALPHA);
+      OPT(STRIP_FILLER);
+      OPT(STRIP_FILLER_BEFORE);
+      OPT(STRIP_FILLER_AFTER);
+      OPT(GRAY_TO_RGB);
+      OPT(EXPAND_16);
+      OPT(SCALE_16);
+
+      else
+      {
+         fprintf(stderr, "timepng %s: unrecognized transform\n", opt);
+         usage(fp);
+      }
+   }
+
+   /* Handle the files: */
+   if (argc > 1 && nfiles > 0)
+      usage(fp); /* Additional files not valid with --dissemble */
+
+   else if (argc > 1)
+   {
+      int i;
+
+      for (i=1; i<argc; ++i)
+      {
+         if (nfiles == INT_MAX)
          {
-            if (add_one_file(fp, argv[i]))
+            fprintf(stderr, "%s: skipped, too many files\n", argv[i]);
+            break;
+         }
+
+         else if (add_one_file(fp, argv[i]))
+            ++nfiles;
+      }
+   }
+
+   else if (nfiles == 0) /* Read from stdin without --dissemble */
+   {
+      char filename[FILENAME_MAX+1];
+
+      while (fgets(filename, FILENAME_MAX+1, stdin))
+      {
+         size_t len = strlen(filename);
+
+         if (filename[len-1] == '\n')
+         {
+            filename[len-1] = 0;
+            if (nfiles == INT_MAX)
+            {
+               fprintf(stderr, "%s: skipped, too many files\n", filename);
+               break;
+            }
+
+            else if (add_one_file(fp, filename))
                ++nfiles;
+         }
+
+         else
+         {
+            fprintf(stderr, "timepng: file name too long: ...%s\n",
+               filename+len-32);
+            err = 1;
+            break;
+         }
+      }
+
+      if (ferror(stdin))
+      {
+         fprintf(stderr, "timepng: stdin: read error\n");
+         err = 1;
+      }
+   }
+
+   /* Perform the test, or produce the --assemble output: */
+   if (!err)
+   {
+      if (nfiles > 0)
+      {
+         if (assembly != NULL)
+         {
+            if (fflush(fp) && !ferror(fp) && fclose(fp))
+            {
+               perror(assembly);
+               fprintf(stderr, "%s: close failed\n", assembly);
+            }
 
             else
             {
-               err = 1;
+               printf("%s %d\n", assembly, nfiles);
-               break;
+               fflush(stdout);
+               ok = !ferror(stdout);
             }
          }
+
+         else
+         {
+            ok = perform_one_test(fp, nfiles, transforms);
+            (void)fclose(fp);
+         }
       }
 
       else
-      {
+         usage(fp);
-         char filename[FILENAME_MAX+1];
-
-         while (fgets(filename, FILENAME_MAX+1, stdin))
-         {
-            size_t len = strlen(filename);
-
-            if (filename[len-1] == '\n')
-            {
-               filename[len-1] = 0;
-               if (add_one_file(fp, filename))
-                  ++nfiles;
-
-               else
-               {
-                  err = 1;
-                  break;
-               }
-            }
-
-            else
-            {
-               fprintf(stderr, "timepng: truncated file name ...%s\n",
-                  filename+len-32);
-               err = 1;
-               break;
-            }
-         }
-
-         if (ferror(stdin))
-         {
-            fprintf(stderr, "timepng: stdin: read error\n");
-            err = 1;
-         }
-      }
-
-      if (!err)
-      {
-         if (nfiles > 0)
-            ok = perform_one_test(fp, nfiles);
-
-         else
-            fprintf(stderr, "usage: timepng {files} or ls files | timepng\n");
-      }
-
-      (void)fclose(fp);
    }
 
    else
-      fprintf(stderr, "timepng: could not open temporary file\n");
+      (void)fclose(fp);
 
    /* Exit code 0 on success. */
    return ok == 0;
 }
+#else /* !sufficient support */
+int main(void) { return 77; }
+#endif /* !sufficient support */

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/README

@@ -0,0 +1,83 @@
+OPERATING SYSTEM SPECIFIC MIPS MSA DETECTION
+--------------------------------------------
+
+Detection of the ability to execute MIPS MSA on an MIPS processor requires
+operating system support.  (The information is not available in user mode.)
+
+HOW TO USE THIS
+---------------
+
+This directory contains C code fragments that can be included in mips/mips_init.c
+by setting the macro PNG_MIPS_MSA_FILE to the file name in "" or <> at build
+time.  This setting is not recorded in pnglibconf.h and can be changed simply by
+rebuilding mips/msa_init.o with the required macro definition.
+
+For any of this code to be used the MIPS MSA code must be enabled and run time
+checks must be supported.  I.e.:
+
+#if PNG_MIPS_MSA_OPT > 0
+#ifdef PNG_MIPS_MSA_CHECK_SUPPORTED
+
+This is done in a 'configure' build by passing configure the argument:
+
+   --enable-mips-msa=check
+
+Apart from the basic Linux implementation in contrib/mips-msa/linux.c this code
+is unsupported.  That means that it is not even compiled on a regular basis and
+may be broken in any given minor release.
+
+FILE FORMAT
+-----------
+
+Each file documents its testing status as of the last time it was tested (which
+may have been a long time ago):
+
+STATUS: one of:
+   SUPPORTED: This indicates that the file is included in the regularly
+         performed test builds and bugs are fixed when discovered.
+   COMPILED: This indicates that the code did compile at least once.  See the
+         more detailed description for the extent to which the result was
+         successful.
+   TESTED: This means the code was fully compiled into the libpng test programs
+         and these were run at least once.
+
+BUG REPORTS: an email address to which to send reports of problems
+
+The file is a fragment of C code. It should not define any 'extern' symbols;
+everything should be static.  It must define the function:
+
+static int png_have_msa(png_structp png_ptr);
+
+That function must return 1 if MIPS MSA instructions are supported, 0 if not.
+It must not execute png_error unless it detects a bug.  A png_error will prevent
+the reading of the PNG and in the future, writing too.
+
+BUG REPORTS
+-----------
+
+If you mail a bug report for any file that is not SUPPORTED there may only be
+limited response.  Consider fixing it and sending a patch to fix the problem -
+this is more likely to result in action.
+
+CONTRIBUTIONS
+-------------
+
+You may send contributions of new implementations to
+png-mng-implement@sourceforge.net.  Please write code in strict C90 C where
+possible.  Obviously OS dependencies are to be expected.  If you submit code you
+must have the authors permission and it must have a license that is acceptable
+to the current maintainer; in particular that license must permit modification
+and redistribution.
+
+Please try to make the contribution a single file and give the file a clear and
+unambiguous name that identifies the target OS.  If multiple files really are
+required put them all in a sub-directory.
+
+You must also be prepared to handle bug reports from users of the code, either
+by joining the png-mng-implement mailing list or by providing an email for the
+"BUG REPORTS" entry or both.  Please make sure that the header of the file
+contains the STATUS and BUG REPORTS fields as above.
+
+Please list the OS requirements as precisely as possible.  Ideally you should
+also list the environment in which the code has been tested and certainly list
+any environments where you suspect it might not work.

contrib/mips-msa/linux.c

@@ -0,0 +1,55 @@
+
+/* contrib/mips-msa/linux.c
+ *
+ * Copyright (c) 2020-2023 Cosmin Truta
+ * Copyright (c) 2016 Glenn Randers-Pehrson
+ * Written by Mandar Sahastrabuddhe, 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
+ *
+ * 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
+ */
+
+#include <elf.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+static int
+png_have_msa(png_structp png_ptr)
+{
+   Elf64_auxv_t aux;
+   int fd;
+   int has_msa = 0;
+
+   fd = open("/proc/self/auxv", O_RDONLY);
+   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;
+
+            has_msa = (hwcap >> 1) & 1;
+            break;
+         }
+      }
+      close(fd);
+   }
+#ifdef PNG_WARNINGS_SUPPORTED
+   else
+      png_warning(png_ptr, "/proc/self/auxv open failed");
+#endif
+
+   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@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

@@ -1,71 +1,52 @@
 /*
  *  png2pnm.c --- conversion from PNG-file to PGM/PPM-file
- *  copyright (C) 1999 by Willem van Schaik <willem@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[]);
+int main (int argc, char *argv[]);
 void usage ();
-BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL alpha);
+BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file,
+              BOOL raw, BOOL alpha);
+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++)
   {
@@ -84,21 +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", argv[argi]);
+            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 */
     }
@@ -106,17 +89,18 @@ int main(int argc, char *argv[])
     {
       if ((fp_rd = fopen (argv[argi], "rb")) == NULL)
       {
-             fprintf (stderr, "PNG2PNM\n");
+        fprintf (stderr, "PNG2PNM\n");
-            fprintf (stderr, "Error:  file %s does not exist\n", argv[argi]);
+        fprintf (stderr, "Error:  file %s does not exist\n", argv[argi]);
-            exit (1);
+        exit (1);
       }
     }
     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);
       }
     }
@@ -124,30 +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);
@@ -157,6 +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;
 }
 
@@ -164,21 +150,18 @@ 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");
-  fprintf (stderr, "   -r[aw]   write pnm-file in binary format (P4/P5/P6) (default)\n");
+  fprintf (stderr,
+      "   -r[aw]   write pnm-file in binary format (P4/P5/P6) (default)\n");
   fprintf (stderr, "   -n[oraw] write pnm-file in ascii format (P1/P2/P3)\n");
-  fprintf (stderr, "   -a[lpha] <file>.pgm write PNG alpha channel as pgm-file\n");
+  fprintf (stderr,
+      "   -a[lpha] <file>.pgm write PNG alpha channel as pgm-file\n");
   fprintf (stderr, "   -h | -?  print this help-information\n");
 }
 
@@ -186,112 +169,96 @@ void usage()
  *  png2pnm
  */
 
-BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL alpha)
+BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file,
+              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;
 
+  /* initialize the libpng context for reading from png_file */
+
+  png_ptr = png_create_read_struct (png_get_libpng_ver(NULL),
+                                    NULL, NULL, NULL);
+  if (!png_ptr)
+    return FALSE; /* out of memory */
+
+  info_ptr = png_create_info_struct (png_ptr);
+  if (!info_ptr)
+  {
+    png_destroy_read_struct (&png_ptr, NULL, NULL);
+    return FALSE; /* out of memory */
+  }
+
+  if (setjmp (png_jmpbuf (png_ptr)))
+  {
+    png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
+    return FALSE; /* generic libpng error */
+  }
+
+  png_init_io (png_ptr, png_file);
+
+  /* do the actual conversion */
+  ret = do_png2pnm (png_ptr, info_ptr, pnm_file, alpha_file, raw, alpha);
+
+  /* clean up the libpng structures and their internally-managed data */
+  png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
+
+  return ret;
+}
+
+/*
+ *  do_png2pnm - does the conversion in a fully-initialized libpng context
+ */
+
+BOOL do_png2pnm (png_struct *png_ptr, png_info *info_ptr,
+                 FILE *pnm_file, FILE *alpha_file,
+                 BOOL raw, BOOL alpha)
+{
+  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;
-  int           row, col;
+  png_uint_32   row, col, i;
-  int           ret;
-  int           i;
   long          dep_16;
 
-  /* read and check signature in PNG file */
+  /* set up the image transformations that are necessary for the PNM format */
-  ret = fread (buf, 1, 8, png_file);
-  if (ret != 8)
-    return FALSE;
 
-  ret = png_sig_cmp (buf, 0, 8);
+  /* set up (if applicable) the expansion of paletted images to full-color rgb,
-  if (ret)
+   * and the expansion of transparency maps to full alpha-channel */
-    return FALSE;
+  png_set_expand (png_ptr);
 
-  /* create png and info structures */
+  /* set up (if applicable) the expansion of grayscale images to bit-depth 8 */
-
+  png_set_expand_gray_1_2_4_to_8 (png_ptr);
-  png_ptr = png_create_read_struct (PNG_LIBPNG_VER_STRING,
-    NULL, NULL, NULL);
-  if (!png_ptr)
-    return FALSE;   /* out of memory */
-
-  info_ptr = png_create_info_struct (png_ptr);
-  if (!info_ptr)
-  {
-    png_destroy_read_struct (&png_ptr, NULL, NULL);
-    return FALSE;   /* out of memory */
-  }
-
-  if (setjmp (png_jmpbuf(png_ptr)))
-  {
-    png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
-    return FALSE;
-  }
-
-  /* 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 */
-  png_read_info (png_ptr, info_ptr);
-
-  /* get size and bit-depth of the PNG-image */
-  png_get_IHDR (png_ptr, info_ptr,
-    &width, &height, &bit_depth, &color_type,
-    NULL, NULL, NULL);
-
-  /* set-up the transformations */
-
-  /* transform paletted images into full-color rgb */
-  if (color_type == PNG_COLOR_TYPE_PALETTE)
-    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)
-    png_set_expand (png_ptr);
-  /* transform transparency maps into full alpha-channel */
-  if (png_get_valid (png_ptr, info_ptr, PNG_INFO_tRNS))
-    png_set_expand (png_ptr);
 
 #ifdef NJET
-  /* downgrade 16-bit images to 8 bit */
+  /* downgrade 16-bit images to 8-bit */
   if (bit_depth == 16)
     png_set_strip_16 (png_ptr);
   /* transform grayscale images into full-color */
   if (color_type == PNG_COLOR_TYPE_GRAY ||
-    color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+      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 */
-  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,
-   * get rowbytes and channels, and allocate image memory */
-
-  png_read_update_info (png_ptr, info_ptr);
-
-  /* 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 */
-  if (bit_depth == 16)
   {
-    raw = FALSE;
+    double file_gamma;
-#ifdef __TURBOC__
+    if (png_get_gAMA (png_ptr, info_ptr, &file_gamma))
-    pnm_file->flags &= ~((unsigned) _F_BIN);
+      png_set_gamma (png_ptr, (double) 2.2, file_gamma);
-#endif
   }
+#endif
 
-  /* calculate new number of channels and store alpha-presence */
+  /* read the image file, with all of the above image transforms applied */
+  png_read_png (png_ptr, info_ptr, 0, NULL);
+
+  /* get the image size, bit-depth and color-type */
+  png_get_IHDR (png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
+                NULL, NULL, NULL);
+
+  /* calculate the 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)
@@ -308,38 +275,12 @@ BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL a
   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 **) malloc (height * sizeof (png_bytep))) == NULL)
+  /* get address of internally-allocated image data */
-  {
+  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 < (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 */
 
@@ -370,45 +311,67 @@ BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL a
   }
 
   /* write data to PNM file */
-  pix_ptr = png_pixels;
 
   for (row = 0; row < height; row++)
   {
+    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);
+        {
+          fputc ((int) *pix_ptr++, pnm_file);
+          if (bit_depth == 16)
+            fputc ((int) *pix_ptr++, pnm_file);
+        }
         else
-          if (bit_depth == 16){
+        {
-            dep_16 = (long) *pix_ptr++;
+          if (bit_depth == 16)
-            fprintf (pnm_file, "%ld ", (dep_16 << 8) + ((long) *pix_ptr++));
+          {
+            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 */
+        else
         {
+          /* output the alpha-channel as pgm file */
           if (raw)
-            fputc ((int) *pix_ptr++ , alpha_file);
+          {
+            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++;
+            if (bit_depth == 16)
-              fprintf (alpha_file, "%ld ", (dep_16 << 8) + (long) *pix_ptr++);
+            {
+              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)
@@ -420,12 +383,5 @@ BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL a
         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

@@ -1,72 +1,57 @@
 /*
  *  pnm2png.c --- conversion from PBM/PGM/PPM-file to PNG-file
- *  copyright (C) 1999 by Willem van Schaik <willem@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 <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[]);
+int main (int argc, char *argv[]);
 void usage ();
-BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace, BOOL alpha);
+BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file,
-void get_token(FILE *pnm_file, char *token);
+              BOOL interlace, BOOL alpha);
-png_uint_32 get_data (FILE *pnm_file, int depth);
+BOOL do_pnm2png (png_struct *png_ptr, png_info *info_ptr,
-png_uint_32 get_value (FILE *pnm_file, int depth);
+                 FILE *pnm_file, FILE *alpha_file,
+                 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++)
   {
@@ -84,20 +69,20 @@ int main(int argc, char *argv[])
           {
             fprintf (stderr, "PNM2PNG\n");
             fprintf (stderr, "Error:  alpha-channel file %s does not exist\n",
-               argv[argi]);
+                     argv[argi]);
             exit (1);
           }
           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 */
     }
@@ -112,10 +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);
       }
     }
@@ -123,30 +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);
@@ -156,6 +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;
 }
 
@@ -163,20 +151,16 @@ 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");
   fprintf (stderr, "   -i[nterlace]   write png-file with interlacing on\n");
-  fprintf (stderr, "   -a[lpha] <file>.pgm read PNG alpha channel as pgm-file\n");
+  fprintf (stderr,
+      "   -a[lpha] <file>.pgm read PNG alpha channel as pgm-file\n");
   fprintf (stderr, "   -h | -?  print this help-information\n");
 }
 
@@ -184,102 +168,101 @@ void usage()
  *  pnm2png
  */
 
-BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace, BOOL alpha)
+BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file,
+              BOOL interlace, BOOL alpha)
 {
-  png_struct    *png_ptr = NULL;
+  png_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;
-  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);
+  if (!png_ptr)
+    return FALSE; /* out of memory */
+
+  info_ptr = png_create_info_struct (png_ptr);
+  if (!info_ptr)
+  {
+    png_destroy_write_struct (&png_ptr, NULL);
+    return FALSE; /* out of memory */
+  }
+
+  if (setjmp (png_jmpbuf (png_ptr)))
+  {
+    png_destroy_write_struct (&png_ptr, &info_ptr);
+    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;
-  unsigned long   ul_width=0, ul_alpha_width=0;
-  unsigned long   ul_height=0, ul_alpha_height=0;
-  unsigned long   ul_maxval=0;
-  png_uint_32   width, alpha_width;
-  png_uint_32   height, alpha_height;
-  png_uint_32   maxval;
-  int           bit_depth = 0;
   int           channels;
-  int           alpha_depth = 0;
+  char          magic_token[4];
-  int           alpha_present;
+  BOOL          raw;
-  int           row, col;
+  png_uint_32   width, height, maxval;
-  BOOL          raw, alpha_raw = FALSE;
+  png_uint_32   row_bytes;
-#if defined(PNG_WRITE_INVERT_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
+  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 */
-  {
-    return FALSE;
-  }
-  else if ((type_token[1] == '1') || (type_token[1] == '4'))
-  {
-#if defined(PNG_WRITE_INVERT_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
-    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)
+  if ((magic_token[1] == '1') || (magic_token[1] == '4'))
-      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');
+    if ((fscan_pnm_uint_32 (pnm_file, &width) != 1) ||
-    color_type = PNG_COLOR_TYPE_RGB;
+        (fscan_pnm_uint_32 (pnm_file, &height) != 1))
-    get_token(pnm_file, width_token);
+      return FALSE; /* bad PBM file header */
-    sscanf (width_token, "%lu", &ul_width);
+  } else if ((magic_token[1] == '2') || (magic_token[1] == '5') ||
-    width = (png_uint_32) ul_width;
+             (magic_token[1] == '3') || (magic_token[1] == '6'))
-    get_token(pnm_file, height_token);
+  {
-    sscanf (height_token, "%lu", &ul_height);
+    if ((fscan_pnm_uint_32 (pnm_file, &width) != 1) ||
-    height = (png_uint_32) ul_height;
+        (fscan_pnm_uint_32 (pnm_file, &height) != 1) ||
-    get_token(pnm_file, maxval_token);
+        (fscan_pnm_uint_32 (pnm_file, &maxval) != 1))
-    sscanf (maxval_token, "%lu", &ul_maxval);
+      return FALSE; /* bad PGM/PPM file header */
-    maxval = (png_uint_32) ul_maxval;
+  }
-    if (maxval <= 1)
+
+  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;
@@ -287,8 +270,34 @@ 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] == '3') || (magic_token[1] == '6'))
+  {
+    raw = (magic_token[1] == '6');
+    color_type = PNG_COLOR_TYPE_RGB;
+    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 (magic_token[1] == '7')
+  {
+    fprintf (stderr, "PNM2PNG can't read PAM (P7) files\n");
+    return FALSE;
   }
   else
   {
@@ -299,49 +308,36 @@ 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_depth = 1;
-    {
+    else if (maxval <= 3)
-      alpha_raw = (type_token[1] == '5');
+      alpha_depth = 2;
-      get_token(alpha_file, width_token);
+    else if (maxval <= 15)
-      sscanf (width_token, "%lu", &ul_alpha_width);
+      alpha_depth = 4;
-      alpha_width=(png_uint_32) ul_alpha_width;
+    else if (maxval <= 255)
-      if (alpha_width != width)
+      alpha_depth = 8;
-        return FALSE;
+    else if (maxval <= 65535U)
-      get_token(alpha_file, height_token);
+      alpha_depth = 16;
-      sscanf (height_token, "%lu", &ul_alpha_height);
+    else /* maxval > 65535U */
-      alpha_height = (png_uint_32) ul_alpha_height;
+      return FALSE;
-      if (alpha_height != height)
+    if (alpha_depth != bit_depth)
-        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;
-      else if (maxval <= 15)
-        alpha_depth = 4;
-      else if (maxval <= 255)
-        alpha_depth = 8;
-      else /* if (maxval <= 65535) */
-        alpha_depth = 16;
-      if (alpha_depth != bit_depth)
-        return FALSE;
-    }
-    else
-    {
       return FALSE;
-    }
   } /* end if alpha */
 
   /* calculate the number of channels and store alpha-presence */
@@ -354,196 +350,258 @@ BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,
   else if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
     channels = 4;
   else
-    channels = 0; /* should not happen */
+    return FALSE; /* NOTREACHED */
 
   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 *) malloc (row_bytes * height * sizeof (png_byte))) == NULL)
+  if ((row_bytes == 0) ||
+      ((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 */
+  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++)
   {
-#if defined(PNG_WRITE_INVERT_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
+    pix_ptr = row_pointers[row];
-    if (packed_bitmap) {
+    if (packed_bitmap)
+    {
       for (i = 0; i < 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 < 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);
+          {
+            *pix_ptr++ = get_pnm_data (pnm_file, bit_depth);
+            if (bit_depth == 16)
+              *pix_ptr++ = get_pnm_data (pnm_file, bit_depth);
+          }
           else
+          {
             if (bit_depth <= 8)
-              *pix_ptr++ = get_value (pnm_file, bit_depth);
+            {
+              *pix_ptr++ = get_pnm_value (pnm_file, bit_depth);
+            }
             else
             {
-              tmp16 = get_value (pnm_file, bit_depth);
+              val16 = get_pnm_value (pnm_file, bit_depth);
-              *pix_ptr = (png_byte) ((tmp16 >> 8) & 0xFF);
+              *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);
+          {
+            *pix_ptr++ = get_pnm_data (alpha_file, alpha_depth);
+            if (alpha_depth == 16)
+              *pix_ptr++ = get_pnm_data (alpha_file, alpha_depth);
+          }
           else
+          {
             if (alpha_depth <= 8)
-              *pix_ptr++ = get_value (alpha_file, bit_depth);
+            {
+              *pix_ptr++ = get_pnm_value (alpha_file, bit_depth);
+            }
             else
             {
-              tmp16 = get_value (alpha_file, bit_depth);
+              val16 = get_pnm_value (alpha_file, bit_depth);
-              *pix_ptr++ = (png_byte) ((tmp16 >> 8) & 0xFF);
+              *pix_ptr++ = (png_byte) ((val16 >> 8) & 0xFF);
-              *pix_ptr++ = (png_byte) (tmp16 & 0xFF);
+              *pix_ptr++ = (png_byte) (val16 & 0xFF);
             }
-        } /* if alpha */
+          }
-      } /* if packed_bitmap */
+        } /* end if alpha */
+      } /* end if packed_bitmap */
     } /* end for col */
   } /* end for row */
 
-  /* prepare the standard PNG structures */
+  /* we're going to write more or less the same PNG as the input file */
-  png_ptr = png_create_write_struct (PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+  png_set_IHDR (png_ptr, info_ptr, width, height, bit_depth, color_type,
-  if (!png_ptr)
+                (!interlace) ? PNG_INTERLACE_NONE : PNG_INTERLACE_ADAM7,
-  {
+                PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
-    return FALSE;
-  }
-  info_ptr = png_create_info_struct (png_ptr);
-  if (!info_ptr)
-  {
-    png_destroy_write_struct (&png_ptr, (png_infopp) 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, (png_infopp) 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);
 
   /* 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, (png_infopp) NULL);
-      return FALSE;
-    }
-  }
-
-  /* set the individual row_pointers to point at the correct offsets */
-  for (i = 0; i < (height); i++)
-    row_pointers[i] = png_pixels + i * row_bytes;
-
   /* write out the entire image data in one call */
   png_write_image (png_ptr, row_pointers);
 
-  /* write the additional chuncks to the PNG file (not really needed) */
+  /* write the additional chunks to the PNG file (not really needed) */
   png_write_end (png_ptr, info_ptr);
 
-  /* clean up after the write, and free any memory allocated */
-  png_destroy_write_struct (&png_ptr, (png_infopp) NULL);
-
-  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;
+    }
+    if (++i == token_buf_size - 1) break;
+    token_buf[i] = (char) ret;
   }
-  while ((token[i] != '\n') && (token[i] != '\r') && (token[i] != ' '));
+  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++)
@@ -551,7 +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;
   }
 
@@ -566,25 +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;
 
@@ -596,4 +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

@@ -1,8 +1,8 @@
 
 pngsuite
 --------
-(c) Willem van Schaik, 1999, 2011, 2012
+Copyright (c) Willem van Schaik, 1999, 2011, 2012
-Two images are by Glenn Randers-Pehrson, 2012
+Two images (ftbbn0g01.png and ftbbn0g02.png) are by Glenn Randers-Pehrson, 2012
 
 Permission to use, copy, modify, and distribute these images for any
 purpose and without fee is hereby granted.
@@ -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
@@ -101,5 +103,5 @@ Testing basn6a16.png: PASS (1072 zero samples)
 libpng passes test
 
 Willem van Schaik
-<willem@schaik.com>
+<willem at schaik.com>
 October 1999

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