Harden a vestigial check against overflow inside png_zalloc

Reported-by: Sergio Atienza Pastor, MTP Métodos y Tecnología

.cmake-format.yaml

@@ -39,8 +39,8 @@ disabled_codes: [
   # re-enable the "invalid variable name XXX" messages.
   "C0103",
 
-  # A custom command with one output doesn't really need a comment because
+  # TODO:
-  # the default "generating XXX" is a good message already.
+  # Add brief COMMENT arguments to the `add_custom_target` commands.
   "C0113",
 ]
 
@@ -82,10 +82,10 @@ keyword_pattern: "[A-Z][0-9A-Z_]+"
 # before considering the loop a parser
 max_conditionals_custom_parser: 2
 
-# Require at least this many newlines between statements
+# Require at least this many newlines between statements;
+# require no more than this many newlines between statements;
+# etc.
 min_statement_spacing: 1
-
-# Require no more than this many newlines between statements
 max_statement_spacing: 2
 max_returns: 6
 max_branches: 12

.github/workflows/lint.yml

@@ -23,6 +23,8 @@ jobs:
           restore-keys: ${{ runner.os }}-pip-
       - name: Install yamllint
         run: pip install yamllint
+      - name: Install editorconfig-checker
+        uses: editorconfig-checker/action-editorconfig-checker@main
       - name: Check out the code
         uses: actions/checkout@v4
       - name: Run the linting script

.gitignore

@@ -122,6 +122,7 @@ ipch/
 *.out
 *out.png
 [._]deps/
+[._]libs/
 .dirstamp
 /Makefile
 /autom4te.cache/
@@ -143,13 +144,16 @@ pnglibconf.dfn
 pnglibconf.pre
 pngprefix.h
 
-# Libpng test programs
+# Libpng test programs, scripts and artifacts
-png-fix-itxt
+/test-suite.log
-pngcp
+/tests/*.log
-pngfix
+/tests/*.trs
-pngimage
+/png-fix-itxt
-pngstest
+/pngcp
-pngtest
+/pngfix
-pngunknown
+/pngimage
-pngvalid
+/pngstest
-timepng
+/pngtest
+/pngunknown
+/pngvalid
+/timepng

.travis.yml

@@ -1,28 +0,0 @@
-branches:
-  except:
-    - /libpng[0-1][0-8]/
-    - /v[0-1][.][0-8][.][0-9]+/
-
-language: c
-
-os:
-  - freebsd
-  - linux
-  - osx
-
-env:
-  - AUTOMATION=cmake
-  - AUTOMATION=configure
-  - AUTOMATION=makefiles
-
-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_CMAKE_GENERATOR="Xcode"; 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'

ANNOUNCE

@@ -1,5 +1,13 @@
-libpng 1.6.47 - February 18, 2025
+libpng 1.6.51.git
-=================================
+=================
+
+This is a development version, not intended to be a public release.
+It will be replaced by a public release, or by another development
+version, at a later time.
+
+
+libpng 1.6.50 - July 1, 2025
+============================
 
 This is a public release of libpng, intended for use in production code.
 
@@ -9,13 +17,13 @@ Files available for download
 
 Source files with LF line endings (for Unix/Linux):
 
- * libpng-1.6.47.tar.xz (LZMA-compressed, recommended)
+ * libpng-1.6.50.tar.xz (LZMA-compressed, recommended)
- * libpng-1.6.47.tar.gz (deflate-compressed)
+ * libpng-1.6.50.tar.gz (deflate-compressed)
 
 Source files with CRLF line endings (for Windows):
 
- * lpng1647.7z (LZMA-compressed, recommended)
+ * lpng1650.7z (LZMA-compressed, recommended)
- * lpng1647.zip (deflate-compressed)
+ * lpng1650.zip (deflate-compressed)
 
 Other information:
 
@@ -25,19 +33,18 @@ Other information:
  * TRADEMARK.md
 
 
-Changes from version 1.6.46 to version 1.6.47
+Changes from version 1.6.49 to version 1.6.50
 ---------------------------------------------
 
- * Modified the behaviour of colorspace chunks in order to adhere
+ * Improved the detection of the RVV Extension on the RISC-V platform.
-   to the new precedence rules formulated in the latest draft of
+   (Contributed by Filip Wasil)
-   the PNG Specification.
+ * Replaced inline ASM with C intrinsics in the RVV code.
+   (Contributed by Filip Wasil)
+ * Fixed a decoder defect in which unknown chunks trailing IDAT, set
+   to go through the unknown chunk handler, incorrectly triggered
+   out-of-place IEND errors.
    (Contributed by John Bowler)
- * Fixed a latent bug in `png_write_iCCP`.
+ * Fixed the CMake file for cross-platform builds that require `libm`.
-   This would have been a read-beyond-end-of-malloc vulnerability,
-   introduced early in the libpng-1.6.0 development, yet (fortunately!)
-   it was inaccessible before the above-mentioned modification of the
-   colorspace precedence rules, due to pre-existing colorspace checks.
-   (Reported by Bob Friesenhahn; fixed by John Bowler)
 
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net.

AUTHORS

@@ -20,6 +20,7 @@ Authors, for copyright and licensing purposes.
  * Lucas Chollet
  * Magnus Holmgren
  * Mandar Sahastrabuddhe
+ * Manfred Schlaegl
  * Mans Rullgard
  * Matt Sarett
  * Mike Klein
@@ -40,8 +41,9 @@ Authors, for copyright and licensing purposes.
     - Zixu Wang (王子旭)
  * Arm Holdings
     - Richard Townsend
- * Google Inc.
+ * Google LLC
     - Dan Field
+    - Dragoș Tiselice
     - Leon Scroggins III
     - Matt Sarett
     - Mike Klein
@@ -51,6 +53,8 @@ Authors, for copyright and licensing purposes.
     - GuXiWei (顾希伟)
     - JinBo (金波)
     - ZhangLixia (张利霞)
+ * Samsung Group
+    - Filip Wasil
 
 The build projects, the build scripts, the test scripts, and other
 files in the "projects", "scripts" and "tests" directories, have

CHANGES

@@ -6251,6 +6251,35 @@ Version 1.6.47 [February 18, 2025]
     colorspace precedence rules, due to pre-existing colorspace checks.
     (Reported by Bob Friesenhahn; fixed by John Bowler)
 
+Version 1.6.48 [April 30, 2025]
+  Fixed the floating-point version of the mDCv setter `png_set_mDCv`.
+    (Reported by Mohit Bakshi; fixed by John Bowler)
+  Added #error directives to discourage the inclusion of private
+    libpng implementation header files in PNG-supporting applications.
+  Added the CMake build option `PNG_LIBCONF_HEADER`, to be used as an
+    alternative to `DFA_XTRA`.
+  Removed the Travis CI configuration files, with heartfelt thanks for
+    their generous support of our project over the past five years!
+
+Version 1.6.49 [June 12, 2025]
+  Added SIMD-optimized code for the RISC-V Vector Extension (RVV).
+    (Contributed by Manfred Schlaegl, Dragos Tiselice and Filip Wasil)
+  Added various fixes and improvements to the build scripts and to
+    the sample code.
+
+Version 1.6.50 [July 1, 2025]
+  Improved the detection of the RVV Extension on the RISC-V platform.
+    (Contributed by Filip Wasil)
+  Replaced inline ASM with C intrinsics in the RVV code.
+    (Contributed by Filip Wasil)
+  Fixed a decoder defect in which unknown chunks trailing IDAT, set
+    to go through the unknown chunk handler, incorrectly triggered
+    out-of-place IEND errors.
+    (Contributed by John Bowler)
+  Fixed the CMake file for cross-platform builds that require `libm`.
+
+Version 1.6.51 [TODO]
+
 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

INSTALL

@@ -136,7 +136,7 @@ Your directory structure should look like this:
              depcomp, install-sh, mkinstalldirs, test-pngtest.sh, etc.
           contrib
              arm-neon, conftest, examples, gregbook, libtests, pngminim,
-             pngminus, pngsuite, tools, visupng
+             pngminus, pngsuite, tools, visupng, riscv-rvv
           projects
              owatcom, visualc71, vstudio
           scripts
@@ -289,6 +289,7 @@ such as one of
    --enable-mips-msa=yes
    --enable-intel-sse=yes
    --enable-powerpc-vsx=yes
+   --enable-riscv-rvv=yes
 
 or enable them all at once with
 
@@ -301,6 +302,7 @@ or more of
    CPPFLAGS += "-DPNG_MIPS_MSA"
    CPPFLAGS += "-DPNG_INTEL_SSE"
    CPPFLAGS += "-DPNG_POWERPC_VSX"
+   CPPFLAGS += "-DPNG_RISCV_RVV"
 
 See for example scripts/makefile.linux-opt
 
@@ -317,13 +319,15 @@ 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"
+   -DPNG_INTEL_SSE_OPT=0, -DPNG_POWERPC_VSX_OPT=0,
+   -DPNG_RISCV_RVV_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
+            -DPNG_MIPS_MSA=no -DPNG_POWERPC_VSX=no \
+            -DPNG_RISCV_RVV=no
 
 or disable them all at once with
 

Makefile.am

@@ -134,13 +134,20 @@ libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES += powerpc/powerpc_init.c\
         powerpc/filter_vsx_intrinsics.c
 endif
 
+if PNG_RISCV_RVV
+noinst_LTLIBRARIES= libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv.la
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la_SOURCES = riscv/riscv_init.c\
+        riscv/filter_rvv_intrinsics.c
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la_CFLAGS = -march=rv64gv
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LIBADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv.la
+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
@@ -163,6 +170,10 @@ else
   libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES = libpng.sym
 endif
 
+if PNG_RISCV_RVV
+  libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES += libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv.la
+endif
+
 if PNG_LOONGARCH_LSX
   libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES += libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx.la
 endif

Makefile.in

@@ -1,7 +1,7 @@
-# Makefile.in generated by automake 1.17 from Makefile.am.
+# Makefile.in generated by automake 1.18.1 from Makefile.am.
 # @configure_input@
 
-# Copyright (C) 1994-2024 Free Software Foundation, Inc.
+# Copyright (C) 1994-2025 Free Software Foundation, Inc.
 
 # This Makefile.in is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -130,8 +130,9 @@ host_triplet = @host@
 @HAVE_LD_VERSION_SCRIPT_TRUE@@HAVE_SOLARIS_LD_FALSE@am__append_9 = -Wl,--version-script=libpng.vers
 #   Only restricted exports when possible
 @HAVE_LD_VERSION_SCRIPT_FALSE@am__append_10 = -export-symbols libpng.sym
-@PNG_LOONGARCH_LSX_TRUE@am__append_11 = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx.la
+@PNG_RISCV_RVV_TRUE@am__append_11 = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv.la
-@DO_PNG_PREFIX_TRUE@am__append_12 = -DPNG_PREFIX='@PNG_PREFIX@'
+@PNG_LOONGARCH_LSX_TRUE@am__append_12 = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx.la
+@DO_PNG_PREFIX_TRUE@am__append_13 = -DPNG_PREFIX='@PNG_PREFIX@'
 subdir = .
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/scripts/autoconf/libtool.m4 \
@@ -239,6 +240,18 @@ libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la_LINK = $(LIBTOOL) $(AM_V_lt) \
 	$(CCLD) $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la_CFLAGS) \
 	$(CFLAGS) $(AM_LDFLAGS) $(LDFLAGS) -o $@
 @PNG_LOONGARCH_LSX_TRUE@am_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la_rpath =
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la_LIBADD =
+am__libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la_SOURCES_DIST =  \
+	riscv/riscv_init.c riscv/filter_rvv_intrinsics.c
+@PNG_RISCV_RVV_TRUE@am_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la_OBJECTS = riscv/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la-riscv_init.lo \
+@PNG_RISCV_RVV_TRUE@	riscv/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la-filter_rvv_intrinsics.lo
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la_OBJECTS =  \
+	$(am_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la_OBJECTS)
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la_LINK = $(LIBTOOL) $(AM_V_lt) \
+	--tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=link \
+	$(CCLD) $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la_CFLAGS) \
+	$(CFLAGS) $(AM_LDFLAGS) $(LDFLAGS) -o $@
+@PNG_RISCV_RVV_TRUE@am_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la_rpath =
 am__png_fix_itxt_SOURCES_DIST = contrib/tools/png-fix-itxt.c
 @ENABLE_TOOLS_TRUE@am_png_fix_itxt_OBJECTS =  \
 @ENABLE_TOOLS_TRUE@	contrib/tools/png-fix-itxt.$(OBJEXT)
@@ -332,7 +345,9 @@ am__depfiles_remade = ./$(DEPDIR)/png.Plo ./$(DEPDIR)/pngerror.Plo \
 	mips/$(DEPDIR)/filter_msa_intrinsics.Plo \
 	mips/$(DEPDIR)/mips_init.Plo \
 	powerpc/$(DEPDIR)/filter_vsx_intrinsics.Plo \
-	powerpc/$(DEPDIR)/powerpc_init.Plo
+	powerpc/$(DEPDIR)/powerpc_init.Plo \
+	riscv/$(DEPDIR)/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la-filter_rvv_intrinsics.Plo \
+	riscv/$(DEPDIR)/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la-riscv_init.Plo
 am__mv = mv -f
 COMPILE = $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) \
 	$(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS)
@@ -355,12 +370,14 @@ am__v_CCLD_1 =
 SOURCES = $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES) \
 	$(nodist_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES) \
 	$(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la_SOURCES) \
+	$(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la_SOURCES) \
 	$(png_fix_itxt_SOURCES) $(pngcp_SOURCES) $(pngfix_SOURCES) \
 	$(pngimage_SOURCES) $(pngstest_SOURCES) $(pngtest_SOURCES) \
 	$(pngunknown_SOURCES) $(pngvalid_SOURCES) $(timepng_SOURCES)
 DIST_SOURCES =  \
 	$(am__libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES_DIST) \
 	$(am__libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la_SOURCES_DIST) \
+	$(am__libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la_SOURCES_DIST) \
 	$(am__png_fix_itxt_SOURCES_DIST) $(am__pngcp_SOURCES_DIST) \
 	$(am__pngfix_SOURCES_DIST) $(am__pngimage_SOURCES_DIST) \
 	$(am__pngstest_SOURCES_DIST) $(am__pngtest_SOURCES_DIST) \
@@ -510,7 +527,7 @@ am__common_driver_flags = \
 # To be inserted before the command running the test.  Creates the
 # directory for the log if needed.  Stores in $dir the directory
 # containing $f, in $tst the test, in $log the log.  Executes the
-# developer- defined test setup AM_TESTS_ENVIRONMENT (if any), and
+# developer-defined test setup AM_TESTS_ENVIRONMENT (if any), and
 # passes TESTS_ENVIRONMENT.  Set up options for the wrapper that
 # will run the test scripts (or their associated LOG_COMPILER, if
 # thy have one).
@@ -827,21 +844,28 @@ libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES = png.c pngerror.c \
 	$(am__append_4) $(am__append_5) $(am__append_6) \
 	$(am__append_7)
 @PNG_LOONGARCH_LSX_TRUE@noinst_LTLIBRARIES = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx.la
+@PNG_RISCV_RVV_TRUE@noinst_LTLIBRARIES = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv.la
+@PNG_RISCV_RVV_TRUE@libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la_SOURCES = riscv/riscv_init.c\
+@PNG_RISCV_RVV_TRUE@        riscv/filter_rvv_intrinsics.c
+
+@PNG_RISCV_RVV_TRUE@libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la_CFLAGS = -march=rv64gv
+@PNG_LOONGARCH_LSX_TRUE@libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LIBADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx.la
+@PNG_RISCV_RVV_TRUE@libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LIBADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv.la
 @PNG_LOONGARCH_LSX_TRUE@libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la_SOURCES = loongarch/loongarch_lsx_init.c\
 @PNG_LOONGARCH_LSX_TRUE@	loongarch/filter_lsx_intrinsics.c
 
 @PNG_LOONGARCH_LSX_TRUE@libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la_CFLAGS = -mlsx
-@PNG_LOONGARCH_LSX_TRUE@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
 nodist_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES = pnglibconf.h
 libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LDFLAGS = -no-undefined \
 	-export-dynamic -version-number \
 	@PNGLIB_MAJOR@@PNGLIB_MINOR@:@PNGLIB_RELEASE@:0 \
 	$(am__append_8) $(am__append_9) $(am__append_10)
 @HAVE_LD_VERSION_SCRIPT_FALSE@libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES =  \
-@HAVE_LD_VERSION_SCRIPT_FALSE@	libpng.sym $(am__append_11)
+@HAVE_LD_VERSION_SCRIPT_FALSE@	libpng.sym $(am__append_11) \
+@HAVE_LD_VERSION_SCRIPT_FALSE@	$(am__append_12)
 @HAVE_LD_VERSION_SCRIPT_TRUE@libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES =  \
-@HAVE_LD_VERSION_SCRIPT_TRUE@	libpng.vers $(am__append_11)
+@HAVE_LD_VERSION_SCRIPT_TRUE@	libpng.vers $(am__append_11) \
+@HAVE_LD_VERSION_SCRIPT_TRUE@	$(am__append_12)
 pkginclude_HEADERS = png.h pngconf.h
 nodist_pkginclude_HEADERS = pnglibconf.h
 pkgconfig_DATA = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.pc
@@ -875,7 +899,7 @@ SUFFIXES = .chk .out
 SYMBOL_CFLAGS = -DPNGLIB_LIBNAME='PNG@PNGLIB_MAJOR@@PNGLIB_MINOR@_0' \
 	-DPNGLIB_VERSION='@PNGLIB_VERSION@' \
 	-DSYMBOL_PREFIX='$(SYMBOL_PREFIX)' -DPNG_NO_USE_READ_MACROS \
-	-DPNG_BUILDING_SYMBOL_TABLE $(am__append_12)
+	-DPNG_BUILDING_SYMBOL_TABLE $(am__append_13)
 
 # EXT_LIST is a list of the possibly library directory extensions, this exists
 # because we can't find a good way of discovering the file extensions that are
@@ -1087,6 +1111,19 @@ loongarch/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la-filter_lsx_intrinsics.lo:  \
 
 libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx.la: $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la_OBJECTS) $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la_DEPENDENCIES) $(EXTRA_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la_DEPENDENCIES) 
 	$(AM_V_CCLD)$(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la_LINK) $(am_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la_rpath) $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la_OBJECTS) $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la_LIBADD) $(LIBS)
+riscv/$(am__dirstamp):
+	@$(MKDIR_P) riscv
+	@: >>riscv/$(am__dirstamp)
+riscv/$(DEPDIR)/$(am__dirstamp):
+	@$(MKDIR_P) riscv/$(DEPDIR)
+	@: >>riscv/$(DEPDIR)/$(am__dirstamp)
+riscv/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la-riscv_init.lo:  \
+	riscv/$(am__dirstamp) riscv/$(DEPDIR)/$(am__dirstamp)
+riscv/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la-filter_rvv_intrinsics.lo:  \
+	riscv/$(am__dirstamp) riscv/$(DEPDIR)/$(am__dirstamp)
+
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv.la: $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la_OBJECTS) $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la_DEPENDENCIES) $(EXTRA_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la_DEPENDENCIES) 
+	$(AM_V_CCLD)$(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la_LINK) $(am_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la_rpath) $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la_OBJECTS) $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la_LIBADD) $(LIBS)
 contrib/tools/$(am__dirstamp):
 	@$(MKDIR_P) contrib/tools
 	@: >>contrib/tools/$(am__dirstamp)
@@ -1202,6 +1239,8 @@ mostlyclean-compile:
 	-rm -f mips/*.lo
 	-rm -f powerpc/*.$(OBJEXT)
 	-rm -f powerpc/*.lo
+	-rm -f riscv/*.$(OBJEXT)
+	-rm -f riscv/*.lo
 
 distclean-compile:
 	-rm -f *.tab.c
@@ -1242,6 +1281,8 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@mips/$(DEPDIR)/mips_init.Plo@am__quote@ # am--include-marker
 @AMDEP_TRUE@@am__include@ @am__quote@powerpc/$(DEPDIR)/filter_vsx_intrinsics.Plo@am__quote@ # am--include-marker
 @AMDEP_TRUE@@am__include@ @am__quote@powerpc/$(DEPDIR)/powerpc_init.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@riscv/$(DEPDIR)/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la-filter_rvv_intrinsics.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@riscv/$(DEPDIR)/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la-riscv_init.Plo@am__quote@ # am--include-marker
 
 $(am__depfiles_remade):
 	@$(MKDIR_P) $(@D)
@@ -1287,6 +1328,20 @@ loongarch/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la-filter_lsx_intrinsics.lo: loo
 @AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
 @am__fastdepCC_FALSE@	$(AM_V_CC@am__nodep@)$(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la_CFLAGS) $(CFLAGS) -c -o loongarch/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la-filter_lsx_intrinsics.lo `test -f 'loongarch/filter_lsx_intrinsics.c' || echo '$(srcdir)/'`loongarch/filter_lsx_intrinsics.c
 
+riscv/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la-riscv_init.lo: riscv/riscv_init.c
+@am__fastdepCC_TRUE@	$(AM_V_CC)$(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la_CFLAGS) $(CFLAGS) -MT riscv/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la-riscv_init.lo -MD -MP -MF riscv/$(DEPDIR)/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la-riscv_init.Tpo -c -o riscv/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la-riscv_init.lo `test -f 'riscv/riscv_init.c' || echo '$(srcdir)/'`riscv/riscv_init.c
+@am__fastdepCC_TRUE@	$(AM_V_at)$(am__mv) riscv/$(DEPDIR)/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la-riscv_init.Tpo riscv/$(DEPDIR)/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la-riscv_init.Plo
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	$(AM_V_CC)source='riscv/riscv_init.c' object='riscv/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la-riscv_init.lo' libtool=yes @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCC_FALSE@	$(AM_V_CC@am__nodep@)$(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la_CFLAGS) $(CFLAGS) -c -o riscv/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la-riscv_init.lo `test -f 'riscv/riscv_init.c' || echo '$(srcdir)/'`riscv/riscv_init.c
+
+riscv/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la-filter_rvv_intrinsics.lo: riscv/filter_rvv_intrinsics.c
+@am__fastdepCC_TRUE@	$(AM_V_CC)$(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la_CFLAGS) $(CFLAGS) -MT riscv/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la-filter_rvv_intrinsics.lo -MD -MP -MF riscv/$(DEPDIR)/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la-filter_rvv_intrinsics.Tpo -c -o riscv/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la-filter_rvv_intrinsics.lo `test -f 'riscv/filter_rvv_intrinsics.c' || echo '$(srcdir)/'`riscv/filter_rvv_intrinsics.c
+@am__fastdepCC_TRUE@	$(AM_V_at)$(am__mv) riscv/$(DEPDIR)/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la-filter_rvv_intrinsics.Tpo riscv/$(DEPDIR)/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la-filter_rvv_intrinsics.Plo
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	$(AM_V_CC)source='riscv/filter_rvv_intrinsics.c' object='riscv/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la-filter_rvv_intrinsics.lo' libtool=yes @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCC_FALSE@	$(AM_V_CC@am__nodep@)$(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la_CFLAGS) $(CFLAGS) -c -o riscv/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la-filter_rvv_intrinsics.lo `test -f 'riscv/filter_rvv_intrinsics.c' || echo '$(srcdir)/'`riscv/filter_rvv_intrinsics.c
+
 mostlyclean-libtool:
 	-rm -f *.lo
 
@@ -1297,6 +1352,7 @@ clean-libtool:
 	-rm -rf loongarch/.libs loongarch/_libs
 	-rm -rf mips/.libs mips/_libs
 	-rm -rf powerpc/.libs powerpc/_libs
+	-rm -rf riscv/.libs riscv/_libs
 
 distclean-libtool:
 	-rm -f libtool config.lt
@@ -1913,6 +1969,7 @@ tests/pngimage-full.log: tests/pngimage-full
 @am__EXEEXT_TRUE@	--log-file $$b.log --trs-file $$b.trs \
 @am__EXEEXT_TRUE@	$(am__common_driver_flags) $(AM_TEST_LOG_DRIVER_FLAGS) $(TEST_LOG_DRIVER_FLAGS) -- $(TEST_LOG_COMPILE) \
 @am__EXEEXT_TRUE@	"$$tst" $(AM_TESTS_FD_REDIRECT)
+
 distdir: $(BUILT_SOURCES)
 	$(MAKE) $(AM_MAKEFLAGS) distdir-am
 
@@ -1966,6 +2023,10 @@ dist-bzip2: distdir
 	tardir=$(distdir) && $(am__tar) | BZIP2=$${BZIP2--9} bzip2 -c >$(distdir).tar.bz2
 	$(am__post_remove_distdir)
 
+dist-bzip3: distdir
+	tardir=$(distdir) && $(am__tar) | bzip3 -c >$(distdir).tar.bz3
+	$(am__post_remove_distdir)
+
 dist-lzip: distdir
 	tardir=$(distdir) && $(am__tar) | lzip -c $${LZIP_OPT--9} >$(distdir).tar.lz
 	$(am__post_remove_distdir)
@@ -2009,6 +2070,8 @@ distcheck: dist
 	  eval GZIP= gzip -dc $(distdir).tar.gz | $(am__untar) ;;\
 	*.tar.bz2*) \
 	  bzip2 -dc $(distdir).tar.bz2 | $(am__untar) ;;\
+	*.tar.bz3*) \
+	  bzip3 -dc $(distdir).tar.bz3 | $(am__untar) ;;\
 	*.tar.lz*) \
 	  lzip -dc $(distdir).tar.lz | $(am__untar) ;;\
 	*.tar.xz*) \
@@ -2148,6 +2211,8 @@ distclean-generic:
 	-$(am__rm_f) mips/$(am__dirstamp)
 	-$(am__rm_f) powerpc/$(DEPDIR)/$(am__dirstamp)
 	-$(am__rm_f) powerpc/$(am__dirstamp)
+	-$(am__rm_f) riscv/$(DEPDIR)/$(am__dirstamp)
+	-$(am__rm_f) riscv/$(am__dirstamp)
 
 maintainer-clean-generic:
 	@echo "This command is intended for maintainers to use"
@@ -2201,6 +2266,8 @@ distclean: distclean-am
 	-rm -f mips/$(DEPDIR)/mips_init.Plo
 	-rm -f powerpc/$(DEPDIR)/filter_vsx_intrinsics.Plo
 	-rm -f powerpc/$(DEPDIR)/powerpc_init.Plo
+	-rm -f riscv/$(DEPDIR)/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la-filter_rvv_intrinsics.Plo
+	-rm -f riscv/$(DEPDIR)/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la-riscv_init.Plo
 	-rm -f Makefile
 distclean-am: clean-am distclean-compile distclean-generic \
 	distclean-hdr distclean-libtool distclean-tags
@@ -2288,6 +2355,8 @@ maintainer-clean: maintainer-clean-am
 	-rm -f mips/$(DEPDIR)/mips_init.Plo
 	-rm -f powerpc/$(DEPDIR)/filter_vsx_intrinsics.Plo
 	-rm -f powerpc/$(DEPDIR)/powerpc_init.Plo
+	-rm -f riscv/$(DEPDIR)/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la-filter_rvv_intrinsics.Plo
+	-rm -f riscv/$(DEPDIR)/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv_la-riscv_init.Plo
 	-rm -f Makefile
 maintainer-clean-am: distclean-am maintainer-clean-generic
 
@@ -2320,15 +2389,15 @@ uninstall-man: uninstall-man3 uninstall-man5
 	clean-checkPROGRAMS clean-cscope clean-generic \
 	clean-libLTLIBRARIES clean-libtool clean-noinstLTLIBRARIES \
 	cscope cscopelist-am ctags ctags-am dist dist-all dist-bzip2 \
-	dist-gzip dist-hook dist-lzip dist-shar dist-tarZ dist-xz \
+	dist-bzip3 dist-gzip dist-hook dist-lzip dist-shar dist-tarZ \
-	dist-zip dist-zstd distcheck distclean distclean-compile \
+	dist-xz dist-zip dist-zstd distcheck distclean \
-	distclean-generic distclean-hdr distclean-libtool \
+	distclean-compile distclean-generic distclean-hdr \
-	distclean-tags distcleancheck distdir distuninstallcheck dvi \
+	distclean-libtool distclean-tags distcleancheck distdir \
-	dvi-am html html-am info info-am install install-am \
+	distuninstallcheck dvi dvi-am html html-am info info-am \
-	install-binPROGRAMS install-binSCRIPTS install-data \
+	install install-am install-binPROGRAMS install-binSCRIPTS \
-	install-data-am install-data-hook install-dvi install-dvi-am \
+	install-data install-data-am install-data-hook install-dvi \
-	install-exec install-exec-am install-exec-hook install-html \
+	install-dvi-am install-exec install-exec-am install-exec-hook \
-	install-html-am install-info install-info-am \
+	install-html install-html-am install-info install-info-am \
 	install-libLTLIBRARIES install-man install-man3 install-man5 \
 	install-nodist_pkgincludeHEADERS install-pdf install-pdf-am \
 	install-pkgconfigDATA install-pkgincludeHEADERS install-ps \

README

@@ -1,5 +1,5 @@
-README for libpng version 1.6.47
+README for libpng version 1.6.51.git
-================================
+====================================
 
 See the note about version numbers near the top of `png.h`.
 See `INSTALL` for instructions on how to install libpng.
@@ -147,6 +147,7 @@ Files included in this distribution
     loongarch/    =>  Optimized code for LoongArch LSX
     mips/         =>  Optimized code for MIPS MSA and MIPS MMI
     powerpc/      =>  Optimized code for PowerPC VSX
+    riscv/        =>  Optimized code for the RISC-V platform
     ci/           =>  Scripts for continuous integration
     contrib/      =>  External contributions
         arm-neon/     =>  Optimized code for the ARM-NEON platform
@@ -162,6 +163,7 @@ Files included in this distribution
                           programs demonstrating the use of pngusr.dfa
         pngminus/     =>  Simple pnm2png and png2pnm programs
         pngsuite/     =>  Test images
+        riscv-rvv/    =>  Optimized code for the RISC-V Vector platform
         testpngs/     =>  Test images
         tools/        =>  Various tools
         visupng/      =>  VisualPng, a Windows viewer for PNG images

aclocal.m4

@@ -1,6 +1,6 @@
-# generated automatically by aclocal 1.17 -*- Autoconf -*-
+# generated automatically by aclocal 1.18.1 -*- Autoconf -*-
 
-# Copyright (C) 1996-2024 Free Software Foundation, Inc.
+# Copyright (C) 1996-2025 Free Software Foundation, Inc.
 
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -20,7 +20,7 @@ You have another version of autoconf.  It may work, but is not guaranteed to.
 If you have problems, you may need to regenerate the build system entirely.
 To do so, use the procedure documented by the package, typically 'autoreconf'.])])
 
-# Copyright (C) 2002-2024 Free Software Foundation, Inc.
+# Copyright (C) 2002-2025 Free Software Foundation, Inc.
 #
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -32,10 +32,10 @@ To do so, use the procedure documented by the package, typically 'autoreconf'.])
 # generated from the m4 files accompanying Automake X.Y.
 # (This private macro should not be called outside this file.)
 AC_DEFUN([AM_AUTOMAKE_VERSION],
-[am__api_version='1.17'
+[am__api_version='1.18'
 dnl Some users find AM_AUTOMAKE_VERSION and mistake it for a way to
 dnl require some minimum version.  Point them to the right macro.
-m4_if([$1], [1.17], [],
+m4_if([$1], [1.18.1], [],
       [AC_FATAL([Do not call $0, use AM_INIT_AUTOMAKE([$1]).])])dnl
 ])
 
@@ -51,14 +51,14 @@ m4_define([_AM_AUTOCONF_VERSION], [])
 # Call AM_AUTOMAKE_VERSION and AM_AUTOMAKE_VERSION so they can be traced.
 # This function is AC_REQUIREd by AM_INIT_AUTOMAKE.
 AC_DEFUN([AM_SET_CURRENT_AUTOMAKE_VERSION],
-[AM_AUTOMAKE_VERSION([1.17])dnl
+[AM_AUTOMAKE_VERSION([1.18.1])dnl
 m4_ifndef([AC_AUTOCONF_VERSION],
   [m4_copy([m4_PACKAGE_VERSION], [AC_AUTOCONF_VERSION])])dnl
 _AM_AUTOCONF_VERSION(m4_defn([AC_AUTOCONF_VERSION]))])
 
 # Figure out how to run the assembler.                      -*- Autoconf -*-
 
-# Copyright (C) 2001-2024 Free Software Foundation, Inc.
+# Copyright (C) 2001-2025 Free Software Foundation, Inc.
 #
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -78,7 +78,7 @@ _AM_IF_OPTION([no-dependencies],, [_AM_DEPENDENCIES([CCAS])])dnl
 
 # AM_AUX_DIR_EXPAND                                         -*- Autoconf -*-
 
-# Copyright (C) 2001-2024 Free Software Foundation, Inc.
+# Copyright (C) 2001-2025 Free Software Foundation, Inc.
 #
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -130,7 +130,7 @@ am_aux_dir=`cd "$ac_aux_dir" && pwd`
 
 # AM_CONDITIONAL                                            -*- Autoconf -*-
 
-# Copyright (C) 1997-2024 Free Software Foundation, Inc.
+# Copyright (C) 1997-2025 Free Software Foundation, Inc.
 #
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -161,7 +161,7 @@ AC_CONFIG_COMMANDS_PRE(
 Usually this means the macro was only invoked conditionally.]])
 fi])])
 
-# Copyright (C) 1999-2024 Free Software Foundation, Inc.
+# Copyright (C) 1999-2025 Free Software Foundation, Inc.
 #
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -352,7 +352,7 @@ _AM_SUBST_NOTMAKE([am__nodep])dnl
 
 # Generate code to set up dependency tracking.              -*- Autoconf -*-
 
-# Copyright (C) 1999-2024 Free Software Foundation, Inc.
+# Copyright (C) 1999-2025 Free Software Foundation, Inc.
 #
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -420,7 +420,7 @@ AC_DEFUN([AM_OUTPUT_DEPENDENCY_COMMANDS],
 
 # Do all the work for Automake.                             -*- Autoconf -*-
 
-# Copyright (C) 1996-2024 Free Software Foundation, Inc.
+# Copyright (C) 1996-2025 Free Software Foundation, Inc.
 #
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -520,8 +520,9 @@ AC_REQUIRE([AC_PROG_AWK])dnl
 AC_REQUIRE([AC_PROG_MAKE_SET])dnl
 AC_REQUIRE([AM_SET_LEADING_DOT])dnl
 _AM_IF_OPTION([tar-ustar], [_AM_PROG_TAR([ustar])],
-	      [_AM_IF_OPTION([tar-pax], [_AM_PROG_TAR([pax])],
+  [_AM_IF_OPTION([tar-pax], [_AM_PROG_TAR([pax])],
-			     [_AM_PROG_TAR([v7])])])
+    [_AM_IF_OPTION([tar-v7], [_AM_PROG_TAR([v7])],
+      [_AM_PROG_TAR([ustar])])])])
 _AM_IF_OPTION([no-dependencies],,
 [AC_PROVIDE_IFELSE([AC_PROG_CC],
 		  [_AM_DEPENDENCIES([CC])],
@@ -597,7 +598,7 @@ for _am_header in $config_headers :; do
 done
 echo "timestamp for $_am_arg" >`AS_DIRNAME(["$_am_arg"])`/stamp-h[]$_am_stamp_count])
 
-# Copyright (C) 2001-2024 Free Software Foundation, Inc.
+# Copyright (C) 2001-2025 Free Software Foundation, Inc.
 #
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -618,7 +619,7 @@ if test x"${install_sh+set}" != xset; then
 fi
 AC_SUBST([install_sh])])
 
-# Copyright (C) 2003-2024 Free Software Foundation, Inc.
+# Copyright (C) 2003-2025 Free Software Foundation, Inc.
 #
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -640,7 +641,7 @@ AC_SUBST([am__leading_dot])])
 # Add --enable-maintainer-mode option to configure.         -*- Autoconf -*-
 # From Jim Meyering
 
-# Copyright (C) 1996-2024 Free Software Foundation, Inc.
+# Copyright (C) 1996-2025 Free Software Foundation, Inc.
 #
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -675,7 +676,7 @@ AC_MSG_CHECKING([whether to enable maintainer-specific portions of Makefiles])
 
 # Check to see how 'make' treats includes.	            -*- Autoconf -*-
 
-# Copyright (C) 2001-2024 Free Software Foundation, Inc.
+# Copyright (C) 2001-2025 Free Software Foundation, Inc.
 #
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -718,7 +719,7 @@ AC_SUBST([am__quote])])
 
 # Fake the existence of programs that GNU maintainers use.  -*- Autoconf -*-
 
-# Copyright (C) 1997-2024 Free Software Foundation, Inc.
+# Copyright (C) 1997-2025 Free Software Foundation, Inc.
 #
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -752,7 +753,7 @@ fi
 
 # Helper functions for option handling.                     -*- Autoconf -*-
 
-# Copyright (C) 2001-2024 Free Software Foundation, Inc.
+# Copyright (C) 2001-2025 Free Software Foundation, Inc.
 #
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -781,7 +782,7 @@ AC_DEFUN([_AM_SET_OPTIONS],
 AC_DEFUN([_AM_IF_OPTION],
 [m4_ifset(_AM_MANGLE_OPTION([$1]), [$2], [$3])])
 
-# Copyright (C) 1999-2024 Free Software Foundation, Inc.
+# Copyright (C) 1999-2025 Free Software Foundation, Inc.
 #
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -813,7 +814,10 @@ AC_CACHE_CHECK(
       break
     fi
   done
-  rm -f core conftest*
+  # aligned with autoconf, so not including core; see bug#72225.
+  rm -f -r a.out a.exe b.out conftest.$ac_ext conftest.$ac_objext \
+    conftest.dSYM conftest1.$ac_ext conftest1.$ac_objext conftest1.dSYM \
+    conftest2.$ac_ext conftest2.$ac_objext conftest2.dSYM
   unset am_i])
 if test "$am_cv_prog_cc_c_o" != yes; then
    # Losing compiler, so override with the script.
@@ -828,7 +832,7 @@ AC_LANG_POP([C])])
 # For backward compatibility.
 AC_DEFUN_ONCE([AM_PROG_CC_C_O], [AC_REQUIRE([AC_PROG_CC])])
 
-# Copyright (C) 2022-2024 Free Software Foundation, Inc.
+# Copyright (C) 2022-2025 Free Software Foundation, Inc.
 #
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -844,7 +848,7 @@ AS_IF([(rm -f && rm -fr && rm -rf) 2>/dev/null], [], [am__rm_f_notfound='""'])
 AC_SUBST(am__rm_f_notfound)
 ])
 
-# Copyright (C) 2001-2024 Free Software Foundation, Inc.
+# Copyright (C) 2001-2025 Free Software Foundation, Inc.
 #
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -863,7 +867,7 @@ AC_DEFUN([AM_RUN_LOG],
 
 # Check to make sure that the build environment is sane.    -*- Autoconf -*-
 
-# Copyright (C) 1996-2024 Free Software Foundation, Inc.
+# Copyright (C) 1996-2025 Free Software Foundation, Inc.
 #
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -1032,10 +1036,12 @@ am_lf='
 '
 case `pwd` in
   *[[\\\"\#\$\&\'\`$am_lf]]*)
+    AC_MSG_RESULT([no])
     AC_MSG_ERROR([unsafe absolute working directory name]);;
 esac
 case $srcdir in
   *[[\\\"\#\$\&\'\`$am_lf\ \	]]*)
+    AC_MSG_RESULT([no])
     AC_MSG_ERROR([unsafe srcdir value: '$srcdir']);;
 esac
 
@@ -1088,7 +1094,7 @@ AC_CONFIG_COMMANDS_PRE(
 rm -f conftest.file
 ])
 
-# Copyright (C) 2009-2024 Free Software Foundation, Inc.
+# Copyright (C) 2009-2025 Free Software Foundation, Inc.
 #
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -1157,9 +1163,13 @@ fi
 # empty being verbose).
 AC_DEFUN([AM_SILENT_RULES],
 [AC_REQUIRE([_AM_SILENT_RULES])
-AM_DEFAULT_VERBOSITY=m4_if([$1], [yes], [0], [1])])
+AM_DEFAULT_VERBOSITY=m4_if([$1], [yes], [0], [1])m4_newline
+dnl We intentionally force a newline after the assignment, since a) nothing
+dnl good can come of more text following, and b) that was the behavior
+dnl before 1.17. See https://bugs.gnu.org/72267.
+])
 
-# Copyright (C) 2001-2024 Free Software Foundation, Inc.
+# Copyright (C) 2001-2025 Free Software Foundation, Inc.
 #
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -1187,7 +1197,7 @@ fi
 INSTALL_STRIP_PROGRAM="\$(install_sh) -c -s"
 AC_SUBST([INSTALL_STRIP_PROGRAM])])
 
-# Copyright (C) 2006-2024 Free Software Foundation, Inc.
+# Copyright (C) 2006-2025 Free Software Foundation, Inc.
 #
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -1206,7 +1216,7 @@ AC_DEFUN([AM_SUBST_NOTMAKE], [_AM_SUBST_NOTMAKE($@)])
 
 # Check how to create a tarball.                            -*- Autoconf -*-
 
-# Copyright (C) 2004-2024 Free Software Foundation, Inc.
+# Copyright (C) 2004-2025 Free Software Foundation, Inc.
 #
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -1341,7 +1351,7 @@ AC_SUBST([am__tar])
 AC_SUBST([am__untar])
 ]) # _AM_PROG_TAR
 
-# Copyright (C) 2022-2024 Free Software Foundation, Inc.
+# Copyright (C) 2022-2025 Free Software Foundation, Inc.
 #
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,

arm/arm_init.c

@@ -35,14 +35,14 @@
 #ifndef PNG_ARM_NEON_FILE
 #  if defined(__aarch64__) || defined(_M_ARM64)
      /* ARM Neon is expected to be unconditionally available on ARM64. */
-#    error "PNG_ARM_NEON_CHECK_SUPPORTED must not be defined on ARM64"
+#    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"
+#    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"
+#    error No support for run-time ARM Neon checking; use compile-time options
 #  endif
 #endif
 
@@ -53,7 +53,7 @@ static int png_have_neon(png_structp png_ptr);
 #endif /* PNG_ARM_NEON_CHECK_SUPPORTED */
 
 #ifndef PNG_ALIGNED_MEMORY_SUPPORTED
-#  error "ALIGNED_MEMORY is required; set: -DPNG_ALIGNED_MEMORY_SUPPORTED"
+#  error ALIGNED_MEMORY is required; please define PNG_ALIGNED_MEMORY_SUPPORTED
 #endif
 
 void

ci/README.md

@@ -4,7 +4,7 @@ Scripts for the Continuous Integration of the PNG Reference Library
 Copyright Notice
 ----------------
 
-Copyright (c) 2019-2024 Cosmin Truta.
+Copyright (c) 2019-2025 Cosmin Truta.
 
 Use, modification and distribution are subject to the MIT License.
 Please see the accompanying file `LICENSE_MIT.txt` or visit

ci/ci_lint.sh

@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 set -o errexit -o pipefail -o posix
 
-# Copyright (c) 2019-2024 Cosmin Truta.
+# Copyright (c) 2019-2025 Cosmin Truta.
 #
 # Use, modification and distribution are subject to the MIT License.
 # Please see the accompanying file LICENSE_MIT.txt
@@ -61,7 +61,7 @@ function ci_lint_ci_scripts {
     }
     ci_info "## LINTING: CI scripts ##"
     ci_spawn "$CI_SHELLCHECK" --version
-    find ./ci -maxdepth 1 -name "*.sh" | {
+    find ./ci -name "ci_*.sh" -not -name "ci_env.*.sh" | {
         local my_file
         while IFS="" read -r my_file
         do

ci/ci_shellify.sh

@@ -1,92 +0,0 @@
-#!/usr/bin/env bash
-set -o errexit -o pipefail -o posix
-
-# 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"
-
-function ci_shellify_c {
-    # Convert C preprocessor text, specifically originating
-    # from png.h, to shell scripting text.
-    # Select only the easy-to-parse definitions of PNG_LIBPNG_*.
-    sed -n -e '/^\# *define * PNG_LIBPNG_[^ ]* * ["0-9A-Za-z_]/ p' |
-        sed -e 's/^\# *define * PNG\([^ ]*\) * \([^ ]*\)/PNG\1=\2/' \
-            -e 's/=PNG\([0-9A-Za-z_]*\)/=\${PNG\1}/' \
-            -e 's/^\([^ ]*=[^ ]*\).*$/export \1;/'
-}
-
-function ci_shellify_autoconf {
-    # Convert autoconf (M4) text, specifically originating
-    # from configure.ac, to shell scripting text.
-    # Select only the easy-to-parse definitions of PNGLIB_*.
-    sed -n -e '/^ *PNGLIB_[^ ]*=[$"0-9A-Za-z_]/ p' |
-        sed -e 's/^ *PNG\([0-9A-Za-z_]*\)=\([^# ]*\).*$/PNG\1=\2/' \
-            -e 's/^\([^ ]*=[^ ]*\).*$/export \1;/'
-}
-
-function ci_shellify_cmake {
-    # Convert CMake lists text, specifically originating
-    # from CMakeLists.txt, to shell scripting text.
-    # Select only the easy-to-parse definitions of PNGLIB_*.
-    sed -n -e '/^ *set *(PNGLIB_[^ ]* * [$"0-9A-Za-z_].*)/ p' |
-        sed -e 's/^ *set *(PNG\([^ ]*\) * \([^() ]*\)).*$/PNG\1=\2/' \
-            -e 's/^\([^ ]*=[^ ]*\).*$/export \1;/'
-}
-
-function ci_shellify {
-    local arg filename
-    for arg in "$@"
-    do
-        test -f "$arg" || ci_err "no such file: '$arg'"
-        filename="$(basename -- "$arg")"
-        case "$filename" in
-        ( *.[ch] )
-            [[ $filename == png.h ]] || {
-                ci_err "unable to shellify: '$filename' (expecting: 'png.h')"
-            }
-            ci_shellify_c <"$arg" ;;
-        ( config* | *.ac )
-            [[ $filename == configure.ac ]] || {
-                ci_err "unable to shellify: '$filename' (expecting: 'configure.ac')"
-            }
-            ci_shellify_autoconf <"$arg" ;;
-        ( *CMake* | *cmake* | *.txt )
-            [[ $filename == [Cc][Mm]ake[Ll]ists.txt ]] || {
-                ci_err "unable to shellify: '$filename' (expecting: 'CMakeLists.txt')"
-            }
-            ci_shellify_cmake <"$arg" ;;
-        ( * )
-            ci_err "unable to shellify: '$arg'" ;;
-        esac
-    done
-}
-
-function usage {
-    echo "usage: $CI_SCRIPT_NAME [<options>] <files>..."
-    echo "options: -?|-h|--help"
-    echo "files: png.h|configure.ac|CMakeLists.txt"
-    exit "${@:-0}"
-}
-
-function main {
-    local opt
-    while getopts ":" opt
-    do
-        # This ain't a while-loop. It only pretends to be.
-        [[ $1 == -[?h]* || $1 == --help || $1 == --help=* ]] && usage 0
-        ci_err "unknown option: '$1'"
-    done
-    shift $((OPTIND - 1))
-    [[ $# -eq 0 ]] && usage 2
-    # And... go!
-    ci_shellify "$@"
-}
-
-main "$@"

ci/ci_verify_cmake.sh

@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 set -o errexit -o pipefail -o posix
 
-# Copyright (c) 2019-2024 Cosmin Truta.
+# Copyright (c) 2019-2025 Cosmin Truta.
 #
 # Use, modification and distribution are subject to the MIT License.
 # Please see the accompanying file LICENSE_MIT.txt

ci/ci_verify_configure.sh

@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 set -o errexit -o pipefail -o posix
 
-# Copyright (c) 2019-2024 Cosmin Truta.
+# Copyright (c) 2019-2025 Cosmin Truta.
 #
 # Use, modification and distribution are subject to the MIT License.
 # Please see the accompanying file LICENSE_MIT.txt

ci/ci_verify_makefiles.sh

@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 set -o errexit -o pipefail -o posix
 
-# Copyright (c) 2019-2024 Cosmin Truta.
+# Copyright (c) 2019-2025 Cosmin Truta.
 #
 # Use, modification and distribution are subject to the MIT License.
 # Please see the accompanying file LICENSE_MIT.txt

ci/ci_verify_version.sh

@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 set -o errexit -o pipefail -o posix
 
-# Copyright (c) 2019-2024 Cosmin Truta.
+# Copyright (c) 2019-2025 Cosmin Truta.
 #
 # Use, modification and distribution are subject to the MIT License.
 # Please see the accompanying file LICENSE_MIT.txt
@@ -12,33 +12,43 @@ set -o errexit -o pipefail -o posix
 source "$(dirname "$0")/lib/ci.lib.sh"
 cd "$CI_TOPLEVEL_DIR"
 
-function ci_init_shellify {
+# Declare the global environments collected from various sources.
-    [[ -f $CI_SCRIPT_DIR/ci_shellify.sh ]] || {
+declare CI_ENV_LIBPNG_VER        # collected from png.h
-        ci_err_internal "missing script: '$CI_SCRIPT_DIR/ci_shellify.sh'"
+declare CI_ENV_AUTOCONF_VER      # collected from configure.ac
-    }
+declare CI_ENV_CMAKE_VER         # collected from CMakeLists.txt
-}
+declare CI_ENV_LIBPNGCONFIG_VER  # collected from scripts/libpng-config-head.in
 
 function ci_run_shellify {
+    local my_script my_result
+    my_script="$CI_SCRIPT_DIR/libexec/ci_shellify_${1#--}.sh"
+    shift 1
+    [[ -f $my_script ]] || {
+        ci_err_internal "missing script: '$my_script'"
+    }
     ci_info "shellifying:" "$@"
-    local my_result
+    "$BASH" "$my_script" "$@"
-    "$BASH" "$CI_SCRIPT_DIR/ci_shellify.sh" "$@"
     echo "$my_result" | "$BASH" --posix || ci_err "bad shellify output"
     echo "$my_result"
 }
 
-function ci_verify_version {
+function ci_init_version_verification {
     ci_info "## START OF VERIFICATION ##"
-    local my_env_libpng_ver my_env_autoconf_ver my_env_cmake_ver my_expect
+    CI_ENV_LIBPNG_VER="$(ci_run_shellify --c png.h)"
-    ci_init_shellify
+    echo "$CI_ENV_LIBPNG_VER"
-    my_env_libpng_ver="$(ci_run_shellify png.h)"
+    CI_ENV_AUTOCONF_VER="$(ci_run_shellify --autoconf configure.ac)"
-    echo "$my_env_libpng_ver"
+    echo "$CI_ENV_AUTOCONF_VER"
-    my_env_autoconf_ver="$(ci_run_shellify configure.ac)"
+    CI_ENV_CMAKE_VER="$(ci_run_shellify --cmake CMakeLists.txt)"
-    echo "$my_env_autoconf_ver"
+    echo "$CI_ENV_CMAKE_VER"
-    my_env_cmake_ver="$(ci_run_shellify CMakeLists.txt)"
+    CI_ENV_LIBPNGCONFIG_VER="$(ci_run_shellify --shell scripts/libpng-config-head.in)"
-    echo "$my_env_cmake_ver"
+    echo "$CI_ENV_LIBPNGCONFIG_VER"
-    ci_info "## VERIFYING: png.h version definitions ##"
+}
-    eval "$my_env_libpng_ver"
+
-    local my_expect="${PNG_LIBPNG_VER_MAJOR}.${PNG_LIBPNG_VER_MINOR}.${PNG_LIBPNG_VER_RELEASE}"
+# shellcheck disable=SC2154
+function ci_do_version_verification {
+    local my_expect
+    ci_info "## VERIFYING: version definitions in 'png.h' ##"
+    eval "$CI_ENV_LIBPNG_VER"
+    my_expect="${PNG_LIBPNG_VER_MAJOR}.${PNG_LIBPNG_VER_MINOR}.${PNG_LIBPNG_VER_RELEASE}"
     if [[ "$PNG_LIBPNG_VER_STRING" == "$my_expect"* ]]
     then
         ci_info "matched: \$PNG_LIBPNG_VER_STRING == $my_expect*"
@@ -77,7 +87,7 @@ function ci_verify_version {
     else
         ci_err "mismatched: \$PNG_LIBPNG_VER_BUILD != [01]"
     fi
-    ci_info "## VERIFYING: png.h build definitions ##"
+    ci_info "## VERIFYING: build definitions in 'png.h' ##"
     my_expect="${PNG_LIBPNG_VER_MAJOR}.${PNG_LIBPNG_VER_MINOR}.${PNG_LIBPNG_VER_RELEASE}"
     if [[ "$PNG_LIBPNG_VER_STRING" == "$my_expect" ]]
     then
@@ -110,19 +120,19 @@ function ci_verify_version {
     else
         ci_err "unexpected: \$PNG_LIBPNG_VER_STRING == '$PNG_LIBPNG_VER_STRING'"
     fi
-    ci_info "## VERIFYING: png.h type definitions ##"
+    ci_info "## VERIFYING: type definitions in 'png.h' ##"
     my_expect="$(echo "png_libpng_version_${PNG_LIBPNG_VER_STRING}" | tr . _)"
     ci_spawn grep -w -e "$my_expect" png.h
-    ci_info "## VERIFYING: configure.ac version definitions ##"
+    ci_info "## VERIFYING: version definitions in 'configure.ac' ##"
-    eval "$my_env_autoconf_ver"
+    eval "$CI_ENV_AUTOCONF_VER"
     if [[ "$PNGLIB_VERSION" == "$PNG_LIBPNG_VER_STRING" ]]
     then
         ci_info "matched: \$PNGLIB_VERSION == \$PNG_LIBPNG_VER_STRING"
     else
         ci_err "mismatched: \$PNGLIB_VERSION != \$PNG_LIBPNG_VER_STRING"
     fi
-    ci_info "## VERIFYING: CMakeLists.txt version definitions ##"
+    ci_info "## VERIFYING: version definitions in 'CMakeLists.txt' ##"
-    eval "$my_env_cmake_ver"
+    eval "$CI_ENV_CMAKE_VER"
     if [[ "$PNGLIB_VERSION" == "$PNG_LIBPNG_VER_STRING" && "$PNGLIB_SUBREVISION" == 0 ]]
     then
         ci_info "matched: \$PNGLIB_VERSION == \$PNG_LIBPNG_VER_STRING"
@@ -133,8 +143,26 @@ function ci_verify_version {
     else
         ci_err "mismatched: \$PNGLIB_VERSION != \$PNG_LIBPNG_VER_STRING"
     fi
+    ci_info "## VERIFYING: version definitions in 'scripts/libpng-config-head.in' ##"
+    eval "$CI_ENV_LIBPNGCONFIG_VER"
+    if [[ "$version" == "$PNG_LIBPNG_VER_STRING" ]]
+    then
+        ci_info "matched: \$version == \$PNG_LIBPNG_VER_STRING"
+    else
+        ci_err "mismatched: \$version != \$PNG_LIBPNG_VER_STRING"
+    fi
+}
+
+function ci_finish_version_verification {
     ci_info "## END OF VERIFICATION ##"
-    ci_info "success!"
+    # Relying on "set -o errexit" to not reach here in case of error.
+    ci_info "## SUCCESS ##"
+}
+
+function ci_verify_version {
+    ci_init_version_verification
+    ci_do_version_verification
+    ci_finish_version_verification
 }
 
 function usage {

ci/lib/ci.lib.sh

@@ -1,4 +1,4 @@
-# Copyright (c) 2019-2024 Cosmin Truta.
+# Copyright (c) 2019-2025 Cosmin Truta.
 #
 # Use, modification and distribution are subject to the MIT License.
 # Please see the accompanying file LICENSE_MIT.txt

ci/libexec/ci_shellify_autoconf.sh

@@ -0,0 +1,48 @@
+#!/usr/bin/env bash
+set -o errexit -o pipefail -o posix
+
+# Copyright (c) 2019-2025 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 "$0")/../lib/ci.lib.sh"
+
+function ci_shellify_autoconf {
+    # Convert autoconf (M4) text, specifically originating
+    # from configure.ac, to shell scripting text.
+    # Select only the easy-to-parse definitions of PNGLIB_*.
+    sed -n -e '/^ *PNGLIB_[^ ]*=[$"0-9A-Za-z_]/ p' |
+        sed -e 's/^ *PNG\([0-9A-Za-z_]*\)=\([^# ]*\).*$/PNG\1=\2/' \
+            -e 's/^\([^ ]*=[^ ]*\).*$/export \1;/'
+}
+
+function usage {
+    echo "usage: $CI_SCRIPT_NAME [<options>] configure.ac"
+    echo "options: -?|-h|--help"
+    exit "${@:-0}"
+}
+
+function main {
+    local opt
+    while getopts ":" opt
+    do
+        # This ain't a while-loop. It only pretends to be.
+        [[ $1 == -[?h]* || $1 == --help || $1 == --help=* ]] && usage 0
+        ci_err "unknown option: '$1'"
+    done
+    shift $((OPTIND - 1))
+    [[ $# -eq 0 ]] && usage 2
+    [[ $# -eq 1 ]] || ci_err "too many operands"
+    # And... go!
+    test -e "$1" || ci_err "no such file: '$1'"
+    [[ $(basename -- "$1") == configure.ac ]] || {
+        ci_err "incorrect operand: '$1' (expecting: 'configure.ac')"
+    }
+    ci_shellify_autoconf <"$1"
+}
+
+main "$@"

ci/libexec/ci_shellify_c.sh

@@ -0,0 +1,49 @@
+#!/usr/bin/env bash
+set -o errexit -o pipefail -o posix
+
+# Copyright (c) 2019-2025 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"
+
+function ci_shellify_c {
+    # Convert C preprocessor text, specifically originating
+    # from png.h, to shell scripting text.
+    # Select only the easy-to-parse definitions of PNG_LIBPNG_*.
+    sed -n -e '/^\# *define * PNG_LIBPNG_[^ ]* * ["0-9A-Za-z_]/ p' |
+        sed -e 's/^\# *define * PNG\([^ ]*\) * \([^ ]*\)/PNG\1=\2/' \
+            -e 's/=PNG\([0-9A-Za-z_]*\)/=\${PNG\1}/' \
+            -e 's/^\([^ ]*=[^ ]*\).*$/export \1;/'
+}
+
+function usage {
+    echo "usage: $CI_SCRIPT_NAME [<options>] png.h"
+    echo "options: -?|-h|--help"
+    exit "${@:-0}"
+}
+
+function main {
+    local opt
+    while getopts ":" opt
+    do
+        # This ain't a while-loop. It only pretends to be.
+        [[ $1 == -[?h]* || $1 == --help || $1 == --help=* ]] && usage 0
+        ci_err "unknown option: '$1'"
+    done
+    shift $((OPTIND - 1))
+    [[ $# -eq 0 ]] && usage 2
+    [[ $# -eq 1 ]] || ci_err "too many operands"
+    # And... go!
+    test -e "$1" || ci_err "no such file: '$1'"
+    [[ $(basename -- "$1") == png.h ]] || {
+        ci_err "incorrect operand: '$1' (expecting: 'png.h')"
+    }
+    ci_shellify_c <"$1"
+}
+
+main "$@"

ci/libexec/ci_shellify_cmake.sh

@@ -0,0 +1,49 @@
+#!/usr/bin/env bash
+set -o errexit -o pipefail -o posix
+
+# Copyright (c) 2019-2025 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 "$0")/../lib/ci.lib.sh"
+
+function ci_shellify_cmake {
+    # Convert CMake lists text, specifically originating
+    # from CMakeLists.txt, to shell scripting text.
+    # Select only the easy-to-parse definitions of PNGLIB_*.
+    sed -n -e '/^ *set *(PNGLIB_[^ ]* * [$"0-9A-Za-z_].*)/ p' |
+        sed -e 's/^ *set *(PNG\([^ ]*\) * \([^() ]*\)).*$/PNG\1=\2/' \
+            -e 's/^\([^ ]*=[^ ]*\).*$/export \1;/'
+}
+
+function usage {
+    echo "usage: $CI_SCRIPT_NAME [<options>] CMakeLists.txt"
+    echo "options: -?|-h|--help"
+    exit "${@:-0}"
+}
+
+function main {
+    local opt
+    while getopts ":" opt
+    do
+        # This ain't a while-loop. It only pretends to be.
+        [[ $1 == -[?h]* || $1 == --help || $1 == --help=* ]] && usage 0
+        ci_err "unknown option: '$1'"
+    done
+    shift $((OPTIND - 1))
+    [[ $# -eq 0 ]] && usage 2
+    [[ $# -eq 1 ]] || ci_err "too many operands"
+    # And... go!
+    test -e "$1" || ci_err "no such file: '$1'"
+    filename="$(basename -- "$1")"
+    [[ $filename == [Cc][Mm]ake[Ll]ists.txt ]] || {
+        ci_err "incorrect operand: '$1' (expecting: 'CMakeLists.txt')"
+    }
+    ci_shellify_cmake <"$1"
+}
+
+main "$@"

ci/libexec/ci_shellify_shell.sh

@@ -0,0 +1,46 @@
+#!/usr/bin/env bash
+set -o errexit -o pipefail -o posix
+
+# Copyright (c) 2019-2025 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 "$0")/../lib/ci.lib.sh"
+
+function ci_shellify_shell {
+    # Convert shell scripting text to shell scripting text.
+    # Select only the easy-to-parse version definitions.
+    sed -n -e '/^ *[A-Za-z_][0-9A-Za-z_]*=[0-9][^ #]* *$/ p' |
+        sed -e 's/^ *\([^ ]*=[^ ]*\) *$/export \1;/'
+}
+
+function usage {
+    echo "usage: $CI_SCRIPT_NAME [<options>] libpng-config-head.in"
+    echo "options: -?|-h|--help"
+    exit "${@:-0}"
+}
+
+function main {
+    local opt
+    while getopts ":" opt
+    do
+        # This ain't a while-loop. It only pretends to be.
+        [[ $1 == -[?h]* || $1 == --help || $1 == --help=* ]] && usage 0
+        ci_err "unknown option: '$1'"
+    done
+    shift $((OPTIND - 1))
+    [[ $# -eq 0 ]] && usage 2
+    [[ $# -eq 1 ]] || ci_err "too many operands"
+    # And... go!
+    test -e "$1" || ci_err "no such file: '$1'"
+    [[ $(basename -- "$1") == libpng-config-head.in ]] || {
+        ci_err "incorrect operand: '$1' (expecting: 'libpng-config-head.in')"
+    }
+    ci_shellify_shell <"$1"
+}
+
+main "$@"

compile

@@ -1,9 +1,9 @@
 #! /bin/sh
 # Wrapper for compilers which do not understand '-c -o'.
 
-scriptversion=2024-06-19.01; # UTC
+scriptversion=2025-06-18.21; # UTC
 
-# Copyright (C) 1999-2024 Free Software Foundation, Inc.
+# Copyright (C) 1999-2025 Free Software Foundation, Inc.
 # Written by Tom Tromey <tromey@cygnus.com>.
 #
 # This program is free software; you can redistribute it and/or modify
@@ -37,11 +37,11 @@ IFS=" ""	$nl"
 
 file_conv=
 
-# func_file_conv build_file lazy
+# func_file_conv build_file unneeded_conversions
 # 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
+# type is listed in (the comma separated) UNNEEDED_CONVERSIONS, no
-# take place.
+# conversion will take place.
 func_file_conv ()
 {
   file=$1
@@ -51,9 +51,20 @@ func_file_conv ()
 	# lazily determine how to convert abs files
 	case `uname -s` in
 	  MINGW*)
-	    file_conv=mingw
+	    if test -n "$MSYSTEM" && (cygpath --version) >/dev/null 2>&1; then
+	      # MSYS2 environment.
+	      file_conv=cygwin
+	    else
+	      # Original MinGW environment.
+	      file_conv=mingw
+	    fi
 	    ;;
-	  CYGWIN* | MSYS*)
+	  MSYS*)
+	    # Old MSYS environment, or MSYS2 with 32-bit MSYS2 shell.
+	    file_conv=cygwin
+	    ;;
+	  CYGWIN*)
+	    # Cygwin environment.
 	    file_conv=cygwin
 	    ;;
 	  *)
@@ -63,12 +74,14 @@ func_file_conv ()
       fi
       case $file_conv/,$2, in
 	*,$file_conv,*)
+	  # This is the optimization mentioned above:
+	  # If UNNEEDED_CONVERSIONS contains $file_conv, don't convert.
 	  ;;
 	mingw/*)
 	  file=`cmd //C echo "$file " | sed -e 's/"\(.*\) " *$/\1/'`
 	  ;;
-	cygwin/* | msys/*)
+	cygwin/*)
-	  file=`cygpath -m "$file" || echo "$file"`
+	  file=`cygpath -w "$file" || echo "$file"`
 	  ;;
 	wine/*)
 	  file=`winepath -w "$file" || echo "$file"`
@@ -343,9 +356,9 @@ exit $ret
 # Local Variables:
 # mode: shell-script
 # sh-indentation: 2
-# eval: (add-hook 'before-save-hook 'time-stamp)
+# eval: (add-hook 'before-save-hook 'time-stamp nil t)
 # time-stamp-start: "scriptversion="
-# time-stamp-format: "%:y-%02m-%02d.%02H"
+# time-stamp-format: "%Y-%02m-%02d.%02H"
 # time-stamp-time-zone: "UTC0"
 # time-stamp-end: "; # UTC"
 # End:

config.guess

@@ -4,7 +4,7 @@
 
 # shellcheck disable=SC2006,SC2268 # see below for rationale
 
-timestamp='2024-01-01'
+timestamp='2024-07-27'
 
 # This file is free software; you can redistribute it and/or modify it
 # under the terms of the GNU General Public License as published by
@@ -123,7 +123,7 @@ set_cc_for_build() {
     dummy=$tmp/dummy
     case ${CC_FOR_BUILD-},${HOST_CC-},${CC-} in
 	,,)    echo "int x;" > "$dummy.c"
-	       for driver in cc gcc c89 c99 ; do
+	       for driver in cc gcc c17 c99 c89 ; do
 		   if ($driver -c -o "$dummy.o" "$dummy.c") >/dev/null 2>&1 ; then
 		       CC_FOR_BUILD=$driver
 		       break
@@ -634,7 +634,8 @@ EOF
 		sed 's/^		//' << EOF > "$dummy.c"
 		#include <sys/systemcfg.h>
 
-		main()
+		int
+		main ()
 			{
 			if (!__power_pc())
 				exit(1);
@@ -718,7 +719,8 @@ EOF
 		#include <stdlib.h>
 		#include <unistd.h>
 
-		int main ()
+		int
+		main ()
 		{
 		#if defined(_SC_KERNEL_BITS)
 		    long bits = sysconf(_SC_KERNEL_BITS);
@@ -1621,6 +1623,7 @@ cat > "$dummy.c" <<EOF
 #endif
 #endif
 #endif
+int
 main ()
 {
 #if defined (sony)

config.h.in

@@ -108,6 +108,9 @@
 /* Enable POWERPC VSX optimizations */
 #undef PNG_POWERPC_VSX_OPT
 
+/* Enable RISCV RVV optimizations */
+#undef PNG_RISCV_RVV_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. */

config.sub

@@ -2,9 +2,9 @@
 # Configuration validation subroutine script.
 #   Copyright 1992-2024 Free Software Foundation, Inc.
 
-# shellcheck disable=SC2006,SC2268 # see below for rationale
+# shellcheck disable=SC2006,SC2268,SC2162 # see below for rationale
 
-timestamp='2024-01-01'
+timestamp='2024-05-27'
 
 # This file is free software; you can redistribute it and/or modify it
 # under the terms of the GNU General Public License as published by
@@ -120,7 +120,6 @@ case $# in
 esac
 
 # Split fields of configuration type
-# shellcheck disable=SC2162
 saved_IFS=$IFS
 IFS="-" read field1 field2 field3 field4 <<EOF
 $1
@@ -142,10 +141,20 @@ case $1 in
 		# parts
 		maybe_os=$field2-$field3
 		case $maybe_os in
-			nto-qnx* | linux-* | uclinux-uclibc* \
+			  cloudabi*-eabi* \
-			| uclinux-gnu* | kfreebsd*-gnu* | knetbsd*-gnu* | netbsd*-gnu* \
+			| kfreebsd*-gnu* \
-			| netbsd*-eabi* | kopensolaris*-gnu* | cloudabi*-eabi* \
+			| knetbsd*-gnu* \
-			| storm-chaos* | os2-emx* | rtmk-nova* | managarm-* \
+			| kopensolaris*-gnu* \
+			| linux-* \
+			| managarm-* \
+			| netbsd*-eabi* \
+			| netbsd*-gnu* \
+			| nto-qnx* \
+			| os2-emx* \
+			| rtmk-nova* \
+			| storm-chaos* \
+			| uclinux-gnu* \
+			| uclinux-uclibc* \
 			| windows-* )
 				basic_machine=$field1
 				basic_os=$maybe_os
@@ -161,8 +170,12 @@ case $1 in
 		esac
 		;;
 	*-*)
-		# A lone config we happen to match not fitting any pattern
 		case $field1-$field2 in
+			# Shorthands that happen to contain a single dash
+			convex-c[12] | convex-c3[248])
+				basic_machine=$field2-convex
+				basic_os=
+				;;
 			decstation-3100)
 				basic_machine=mips-dec
 				basic_os=
@@ -170,28 +183,88 @@ case $1 in
 			*-*)
 				# Second component is usually, but not always the OS
 				case $field2 in
-					# Prevent following clause from handling this valid os
+					# Do not treat sunos as a manufacturer
 					sun*os*)
 						basic_machine=$field1
 						basic_os=$field2
 						;;
+					# Manufacturers
+					  3100* \
+					| 32* \
+					| 3300* \
+					| 3600* \
+					| 7300* \
+					| acorn \
+					| altos* \
+					| apollo \
+					| apple \
+					| atari \
+					| att* \
+					| axis \
+					| be \
+					| bull \
+					| cbm \
+					| ccur \
+					| cisco \
+					| commodore \
+					| convergent* \
+					| convex* \
+					| cray \
+					| crds \
+					| dec* \
+					| delta* \
+					| dg \
+					| digital \
+					| dolphin \
+					| encore* \
+					| gould \
+					| harris \
+					| highlevel \
+					| hitachi* \
+					| hp \
+					| ibm* \
+					| intergraph \
+					| isi* \
+					| knuth \
+					| masscomp \
+					| microblaze* \
+					| mips* \
+					| motorola* \
+					| ncr* \
+					| news \
+					| next \
+					| ns \
+					| oki \
+					| omron* \
+					| pc533* \
+					| rebel \
+					| rom68k \
+					| rombug \
+					| semi \
+					| sequent* \
+					| siemens \
+					| sgi* \
+					| siemens \
+					| sim \
+					| sni \
+					| sony* \
+					| stratus \
+					| sun \
+					| sun[234]* \
+					| tektronix \
+					| tti* \
+					| ultra \
+					| unicom* \
+					| wec \
+					| winbond \
+					| wrs)
+						basic_machine=$field1-$field2
+						basic_os=
+						;;
 					zephyr*)
 						basic_machine=$field1-unknown
 						basic_os=$field2
 						;;
-					# Manufacturers
-					dec* | mips* | sequent* | encore* | pc533* | sgi* | sony* \
-					| att* | 7300* | 3300* | delta* | motorola* | sun[234]* \
-					| unicom* | ibm* | next | hp | isi* | apollo | altos* \
-					| convergent* | ncr* | news | 32* | 3600* | 3100* \
-					| hitachi* | c[123]* | convex* | sun | crds | omron* | dg \
-					| ultra | tti* | harris | dolphin | highlevel | gould \
-					| cbm | ns | masscomp | apple | axis | knuth | cray \
-					| microblaze* | sim | cisco \
-					| oki | wec | wrs | winbond)
-						basic_machine=$field1-$field2
-						basic_os=
-						;;
 					*)
 						basic_machine=$field1
 						basic_os=$field2
@@ -272,26 +345,6 @@ case $1 in
 				basic_machine=arm-unknown
 				basic_os=cegcc
 				;;
-			convex-c1)
-				basic_machine=c1-convex
-				basic_os=bsd
-				;;
-			convex-c2)
-				basic_machine=c2-convex
-				basic_os=bsd
-				;;
-			convex-c32)
-				basic_machine=c32-convex
-				basic_os=bsd
-				;;
-			convex-c34)
-				basic_machine=c34-convex
-				basic_os=bsd
-				;;
-			convex-c38)
-				basic_machine=c38-convex
-				basic_os=bsd
-				;;
 			cray)
 				basic_machine=j90-cray
 				basic_os=unicos
@@ -714,15 +767,26 @@ case $basic_machine in
 		vendor=dec
 		basic_os=tops20
 		;;
-	delta | 3300 | motorola-3300 | motorola-delta \
+	delta | 3300 | delta-motorola | 3300-motorola | motorola-delta | motorola-3300)
-	      | 3300-motorola | delta-motorola)
 		cpu=m68k
 		vendor=motorola
 		;;
-	dpx2*)
+	# This used to be dpx2*, but that gets the RS6000-based
+	# DPX/20 and the x86-based DPX/2-100 wrong.  See
+	# https://oldskool.silicium.org/stations/bull_dpx20.htm
+	# https://www.feb-patrimoine.com/english/bull_dpx2.htm
+	# https://www.feb-patrimoine.com/english/unix_and_bull.htm
+	dpx2 | dpx2[23]00 | dpx2[23]xx)
 		cpu=m68k
 		vendor=bull
-		basic_os=sysv3
+		;;
+	dpx2100 | dpx21xx)
+		cpu=i386
+		vendor=bull
+		;;
+	dpx20)
+		cpu=rs6000
+		vendor=bull
 		;;
 	encore | umax | mmax)
 		cpu=ns32k
@@ -837,18 +901,6 @@ case $basic_machine in
 	next | m*-next)
 		cpu=m68k
 		vendor=next
-		case $basic_os in
-		    openstep*)
-		        ;;
-		    nextstep*)
-			;;
-		    ns2*)
-		      basic_os=nextstep2
-			;;
-		    *)
-		      basic_os=nextstep3
-			;;
-		esac
 		;;
 	np1)
 		cpu=np1
@@ -937,7 +989,6 @@ case $basic_machine in
 		;;
 
 	*-*)
-		# shellcheck disable=SC2162
 		saved_IFS=$IFS
 		IFS="-" read cpu vendor <<EOF
 $basic_machine
@@ -972,15 +1023,19 @@ unset -v basic_machine
 
 # Decode basic machines in the full and proper CPU-Company form.
 case $cpu-$vendor in
-	# Here we handle the default manufacturer of certain CPU types in canonical form. It is in
+	# Here we handle the default manufacturer of certain CPU types in canonical form.
-	# some cases the only manufacturer, in others, it is the most popular.
+	# It is in some cases the only manufacturer, in others, it is the most popular.
+	c[12]-convex | c[12]-unknown | c3[248]-convex | c3[248]-unknown)
+		vendor=convex
+		basic_os=${basic_os:-bsd}
+		;;
 	craynv-unknown)
 		vendor=cray
 		basic_os=${basic_os:-unicosmp}
 		;;
 	c90-unknown | c90-cray)
 		vendor=cray
-		basic_os=${Basic_os:-unicos}
+		basic_os=${basic_os:-unicos}
 		;;
 	fx80-unknown)
 		vendor=alliant
@@ -1026,11 +1081,29 @@ case $cpu-$vendor in
 		vendor=alt
 		basic_os=${basic_os:-linux-gnueabihf}
 		;;
-	dpx20-unknown | dpx20-bull)
+
-		cpu=rs6000
+	# Normalized CPU+vendor pairs that imply an OS, if not otherwise specified
-		vendor=bull
+	m68k-isi)
+		basic_os=${basic_os:-sysv}
+		;;
+	m68k-sony)
+		basic_os=${basic_os:-newsos}
+		;;
+	m68k-tektronix)
+		basic_os=${basic_os:-bsd}
+		;;
+	m88k-harris)
+		basic_os=${basic_os:-sysv3}
+		;;
+	i386-bull | m68k-bull)
+		basic_os=${basic_os:-sysv3}
+		;;
+	rs6000-bull)
 		basic_os=${basic_os:-bosx}
 		;;
+	mips-sni)
+		basic_os=${basic_os:-sysv4}
+		;;
 
 	# Here we normalize CPU types irrespective of the vendor
 	amd64-*)
@@ -1038,7 +1111,7 @@ case $cpu-$vendor in
 		;;
 	blackfin-*)
 		cpu=bfin
-		basic_os=linux
+		basic_os=${basic_os:-linux}
 		;;
 	c54x-*)
 		cpu=tic54x
@@ -1061,7 +1134,7 @@ case $cpu-$vendor in
 		;;
 	m68knommu-*)
 		cpu=m68k
-		basic_os=linux
+		basic_os=${basic_os:-linux}
 		;;
 	m9s12z-* | m68hcs12z-* | hcs12z-* | s12z-*)
 		cpu=s12z
@@ -1071,7 +1144,7 @@ case $cpu-$vendor in
 		;;
 	parisc-*)
 		cpu=hppa
-		basic_os=linux
+		basic_os=${basic_os:-linux}
 		;;
 	pentium-* | p5-* | k5-* | k6-* | nexgen-* | viac3-*)
 		cpu=i586
@@ -1085,9 +1158,6 @@ case $cpu-$vendor in
 	pentium4-*)
 		cpu=i786
 		;;
-	pc98-*)
-		cpu=i386
-		;;
 	ppc-* | ppcbe-*)
 		cpu=powerpc
 		;;
@@ -1121,9 +1191,6 @@ case $cpu-$vendor in
 	tx39el-*)
 		cpu=mipstx39el
 		;;
-	x64-*)
-		cpu=x86_64
-		;;
 	xscale-* | xscalee[bl]-*)
 		cpu=`echo "$cpu" | sed 's/^xscale/arm/'`
 		;;
@@ -1179,90 +1246,227 @@ case $cpu-$vendor in
 		# Recognize the canonical CPU types that are allowed with any
 		# company name.
 		case $cpu in
-			1750a | 580 \
+			  1750a \
+			| 580 \
+			| [cjt]90 \
 			| a29k \
-			| aarch64 | aarch64_be | aarch64c | arm64ec \
+			| aarch64 \
+			| aarch64_be \
+			| aarch64c \
 			| abacus \
-			| alpha | alphaev[4-8] | alphaev56 | alphaev6[78] \
+			| alpha \
-			| alpha64 | alpha64ev[4-8] | alpha64ev56 | alpha64ev6[78] \
+			| alpha64 \
-			| alphapca5[67] | alpha64pca5[67] \
+			| alpha64ev56 \
+			| alpha64ev6[78] \
+			| alpha64ev[4-8] \
+			| alpha64pca5[67] \
+			| alphaev56 \
+			| alphaev6[78] \
+			| alphaev[4-8] \
+			| alphapca5[67] \
 			| am33_2.0 \
 			| amdgcn \
-			| arc | arceb | arc32 | arc64 \
+			| arc \
-			| arm | arm[lb]e | arme[lb] | armv* \
+			| arc32 \
-			| avr | avr32 \
+			| arc64 \
+			| arceb \
+			| arm \
+			| arm64e \
+			| arm64ec \
+			| arm[lb]e \
+			| arme[lb] \
+			| armv* \
 			| asmjs \
+			| avr \
+			| avr32 \
 			| ba \
-			| be32 | be64 \
+			| be32 \
-			| bfin | bpf | bs2000 \
+			| be64 \
-			| c[123]* | c30 | [cjt]90 | c4x \
+			| bfin \
-			| c8051 | clipper | craynv | csky | cydra \
+			| bpf \
-			| d10v | d30v | dlx | dsp16xx \
+			| bs2000 \
-			| e2k | elxsi | epiphany \
+			| c30 \
-			| f30[01] | f700 | fido | fr30 | frv | ft32 | fx80 \
+			| c4x \
-			| javascript \
+			| c8051 \
-			| h8300 | h8500 \
+			| c[123]* \
-			| hppa | hppa1.[01] | hppa2.0 | hppa2.0[nw] | hppa64 \
+			| clipper \
+			| craynv \
+			| csky \
+			| cydra \
+			| d10v \
+			| d30v \
+			| dlx \
+			| dsp16xx \
+			| e2k \
+			| elxsi \
+			| epiphany \
+			| f30[01] \
+			| f700 \
+			| fido \
+			| fr30 \
+			| frv \
+			| ft32 \
+			| fx80 \
+			| h8300 \
+			| h8500 \
 			| hexagon \
-			| i370 | i*86 | i860 | i960 | ia16 | ia64 \
+			| hppa \
-			| ip2k | iq2000 \
+			| hppa1.[01] \
+			| hppa2.0 \
+			| hppa2.0[nw] \
+			| hppa64 \
+			| i*86 \
+			| i370 \
+			| i860 \
+			| i960 \
+			| ia16 \
+			| ia64 \
+			| ip2k \
+			| iq2000 \
+			| javascript \
 			| k1om \
 			| kvx \
-			| le32 | le64 \
+			| le32 \
+			| le64 \
 			| lm32 \
-			| loongarch32 | loongarch64 \
+			| loongarch32 \
-			| m32c | m32r | m32rle \
+			| loongarch64 \
-			| m5200 | m68000 | m680[012346]0 | m68360 | m683?2 | m68k \
+			| m32c \
-			| m6811 | m68hc11 | m6812 | m68hc12 | m68hcs12x \
+			| m32r \
-			| m88110 | m88k | maxq | mb | mcore | mep | metag \
+			| m32rle \
-			| microblaze | microblazeel \
+			| m5200 \
+			| m68000 \
+			| m680[012346]0 \
+			| m6811 \
+			| m6812 \
+			| m68360 \
+			| m683?2 \
+			| m68hc11 \
+			| m68hc12 \
+			| m68hcs12x \
+			| m68k \
+			| m88110 \
+			| m88k \
+			| maxq \
+			| mb \
+			| mcore \
+			| mep \
+			| metag \
+			| microblaze \
+			| microblazeel \
 			| mips* \
 			| mmix \
-			| mn10200 | mn10300 \
+			| mn10200 \
+			| mn10300 \
 			| moxie \
-			| mt \
 			| msp430 \
+			| mt \
 			| nanomips* \
-			| nds32 | nds32le | nds32be \
+			| nds32 \
+			| nds32be \
+			| nds32le \
 			| nfp \
-			| nios | nios2 | nios2eb | nios2el \
+			| nios \
-			| none | np1 | ns16k | ns32k | nvptx \
+			| nios2 \
+			| nios2eb \
+			| nios2el \
+			| none \
+			| np1 \
+			| ns16k \
+			| ns32k \
+			| nvptx \
 			| open8 \
 			| or1k* \
 			| or32 \
 			| orion \
+			| pdp10 \
+			| pdp11 \
 			| picochip \
-			| pdp10 | pdp11 | pj | pjl | pn | power \
+			| pj \
-			| powerpc | powerpc64 | powerpc64le | powerpcle | powerpcspe \
+			| pjl \
+			| pn \
+			| power \
+			| powerpc \
+			| powerpc64 \
+			| powerpc64le \
+			| powerpcle \
+			| powerpcspe \
 			| pru \
 			| pyramid \
-			| riscv | riscv32 | riscv32be | riscv64 | riscv64be \
+			| riscv \
-			| rl78 | romp | rs6000 | rx \
+			| riscv32 \
-			| s390 | s390x \
+			| riscv32be \
+			| riscv64 \
+			| riscv64be \
+			| rl78 \
+			| romp \
+			| rs6000 \
+			| rx \
+			| s390 \
+			| s390x \
 			| score \
-			| sh | shl \
+			| sh \
-			| sh[1234] | sh[24]a | sh[24]ae[lb] | sh[23]e | she[lb] | sh[lb]e \
+			| sh64 \
-			| sh[1234]e[lb] |  sh[12345][lb]e | sh[23]ele | sh64 | sh64le \
+			| sh64le \
-			| sparc | sparc64 | sparc64b | sparc64v | sparc86x | sparclet \
+			| sh[12345][lb]e \
+			| sh[1234] \
+			| sh[1234]e[lb] \
+			| sh[23]e \
+			| sh[23]ele \
+			| sh[24]a \
+			| sh[24]ae[lb] \
+			| sh[lb]e \
+			| she[lb] \
+			| shl \
+			| sparc \
+			| sparc64 \
+			| sparc64b \
+			| sparc64v \
+			| sparc86x \
+			| sparclet \
 			| sparclite \
-			| sparcv8 | sparcv9 | sparcv9b | sparcv9v | sv1 | sx* \
+			| sparcv8 \
+			| sparcv9 \
+			| sparcv9b \
+			| sparcv9v \
 			| spu \
+			| sv1 \
+			| sx* \
 			| tahoe \
 			| thumbv7* \
-			| tic30 | tic4x | tic54x | tic55x | tic6x | tic80 \
+			| tic30 \
+			| tic4x \
+			| tic54x \
+			| tic55x \
+			| tic6x \
+			| tic80 \
 			| tron \
 			| ubicom32 \
-			| v70 | v850 | v850e | v850e1 | v850es | v850e2 | v850e2v3 \
+			| v70 \
+			| v810 \
+			| v850 \
+			| v850e \
+			| v850e1 \
+			| v850e2 \
+			| v850e2v3 \
+			| v850es \
 			| vax \
 			| vc4 \
 			| visium \
 			| w65 \
-			| wasm32 | wasm64 \
+			| wasm32 \
+			| wasm64 \
 			| we32k \
-			| x86 | x86_64 | xc16x | xgate | xps100 \
+			| x86 \
-			| xstormy16 | xtensa* \
+			| x86_64 \
+			| xc16x \
+			| xgate \
+			| xps100 \
+			| xstormy16 \
+			| xtensa* \
 			| ymp \
-			| z8k | z80)
+			| z80 \
+			| z8k)
 				;;
 
 			*)
@@ -1307,7 +1511,6 @@ case $basic_os in
 		os=`echo "$basic_os" | sed -e 's|nto-qnx|qnx|'`
 		;;
 	*-*)
-		# shellcheck disable=SC2162
 		saved_IFS=$IFS
 		IFS="-" read kernel os <<EOF
 $basic_os
@@ -1354,6 +1557,23 @@ case $os in
 	unixware*)
 		os=sysv4.2uw
 		;;
+	# The marketing names for NeXT's operating systems were
+	# NeXTSTEP, NeXTSTEP 2, OpenSTEP 3, OpenSTEP 4.  'openstep' is
+	# mapped to 'openstep3', but 'openstep1' and 'openstep2' are
+	# mapped to 'nextstep' and 'nextstep2', consistent with the
+	# treatment of SunOS/Solaris.
+	ns | ns1 | nextstep | nextstep1 | openstep1)
+		os=nextstep
+		;;
+	ns2 | nextstep2 | openstep2)
+		os=nextstep2
+		;;
+	ns3 | nextstep3 | openstep | openstep3)
+		os=openstep3
+		;;
+	ns4 | nextstep4 | openstep4)
+		os=openstep4
+		;;
 	# es1800 is here to avoid being matched by es* (a different OS)
 	es1800*)
 		os=ose
@@ -1424,6 +1644,7 @@ case $os in
 		;;
 	utek*)
 		os=bsd
+		vendor=`echo "$vendor" | sed -e 's|^unknown$|tektronix|'`
 		;;
 	dynix*)
 		os=bsd
@@ -1440,21 +1661,25 @@ case $os in
 	386bsd)
 		os=bsd
 		;;
-	ctix* | uts*)
+	ctix*)
+		os=sysv
+		vendor=`echo "$vendor" | sed -e 's|^unknown$|convergent|'`
+		;;
+	uts*)
 		os=sysv
 		;;
 	nova*)
-		os=rtmk-nova
+		kernel=rtmk
-		;;
+		os=nova
-	ns2)
-		os=nextstep2
 		;;
 	# Preserve the version number of sinix5.
 	sinix5.*)
 		os=`echo "$os" | sed -e 's|sinix|sysv|'`
+		vendor=`echo "$vendor" | sed -e 's|^unknown$|sni|'`
 		;;
 	sinix*)
 		os=sysv4
+		vendor=`echo "$vendor" | sed -e 's|^unknown$|sni|'`
 		;;
 	tpf*)
 		os=tpf
@@ -1595,6 +1820,14 @@ case $cpu-$vendor in
 		os=
 		obj=elf
 		;;
+	# The -sgi and -siemens entries must be before the mips- entry
+	# or we get the wrong os.
+	*-sgi)
+		os=irix
+		;;
+	*-siemens)
+		os=sysv4
+		;;
 	mips*-cisco)
 		os=
 		obj=elf
@@ -1607,7 +1840,8 @@ case $cpu-$vendor in
 		os=
 		obj=coff
 		;;
-	*-tti)	# must be before sparc entry or we get the wrong os.
+	# This must be before the sparc-* entry or we get the wrong os.
+	*-tti)
 		os=sysv3
 		;;
 	sparc-* | *-sun)
@@ -1639,7 +1873,7 @@ case $cpu-$vendor in
 		os=hpux
 		;;
 	*-hitachi)
-		os=hiux
+		os=hiuxwe2
 		;;
 	i860-* | *-att | *-ncr | *-altos | *-motorola | *-convergent)
 		os=sysv
@@ -1683,12 +1917,6 @@ case $cpu-$vendor in
 	*-encore)
 		os=bsd
 		;;
-	*-sgi)
-		os=irix
-		;;
-	*-siemens)
-		os=sysv4
-		;;
 	*-masscomp)
 		os=rtu
 		;;
@@ -1735,40 +1963,193 @@ case $os in
 	ghcjs)
 		;;
 	# Now accept the basic system types.
-	# The portable systems comes first.
 	# Each alternative MUST end in a * to match a version number.
-	gnu* | android* | bsd* | mach* | minix* | genix* | ultrix* | irix* \
+	  abug \
-	     | *vms* | esix* | aix* | cnk* | sunos | sunos[34]* \
+	| aix* \
-	     | hpux* | unos* | osf* | luna* | dgux* | auroraux* | solaris* \
+	| amdhsa* \
-	     | sym* |  plan9* | psp* | sim* | xray* | os68k* | v88r* \
+	| amigados* \
-	     | hiux* | abug | nacl* | netware* | windows* \
+	| amigaos* \
-	     | os9* | macos* | osx* | ios* | tvos* | watchos* \
+	| android* \
-	     | mpw* | magic* | mmixware* | mon960* | lnews* \
+	| aof* \
-	     | amigaos* | amigados* | msdos* | newsos* | unicos* | aof* \
+	| aos* \
-	     | aos* | aros* | cloudabi* | sortix* | twizzler* \
+	| aros* \
-	     | nindy* | vxsim* | vxworks* | ebmon* | hms* | mvs* \
+	| atheos* \
-	     | clix* | riscos* | uniplus* | iris* | isc* | rtu* | xenix* \
+	| auroraux* \
-	     | mirbsd* | netbsd* | dicos* | openedition* | ose* \
+	| aux* \
-	     | bitrig* | openbsd* | secbsd* | solidbsd* | libertybsd* | os108* \
+	| beos* \
-	     | ekkobsd* | freebsd* | riscix* | lynxos* | os400* \
+	| bitrig* \
-	     | bosx* | nextstep* | cxux* | oabi* \
+	| bme* \
-	     | ptx* | ecoff* | winnt* | domain* | vsta* \
+	| bosx* \
-	     | udi* | lites* | ieee* | go32* | aux* | hcos* \
+	| bsd* \
-	     | chorusrdb* | cegcc* | glidix* | serenity* \
+	| cegcc* \
-	     | cygwin* | msys* | moss* | proelf* | rtems* \
+	| chorusos* \
-	     | midipix* | mingw32* | mingw64* | mint* \
+	| chorusrdb* \
-	     | uxpv* | beos* | mpeix* | udk* | moxiebox* \
+	| clix* \
-	     | interix* | uwin* | mks* | rhapsody* | darwin* \
+	| cloudabi* \
-	     | openstep* | oskit* | conix* | pw32* | nonstopux* \
+	| cnk* \
-	     | storm-chaos* | tops10* | tenex* | tops20* | its* \
+	| conix* \
-	     | os2* | vos* | palmos* | uclinux* | nucleus* | morphos* \
+	| cos* \
-	     | scout* | superux* | sysv* | rtmk* | tpf* | windiss* \
+	| cxux* \
-	     | powermax* | dnix* | nx6 | nx7 | sei* | dragonfly* \
+	| cygwin* \
-	     | skyos* | haiku* | rdos* | toppers* | drops* | es* \
+	| darwin* \
-	     | onefs* | tirtos* | phoenix* | fuchsia* | redox* | bme* \
+	| dgux* \
-	     | midnightbsd* | amdhsa* | unleashed* | emscripten* | wasi* \
+	| dicos* \
-	     | nsk* | powerunix* | genode* | zvmoe* | qnx* | emx* | zephyr* \
+	| dnix* \
-	     | fiwix* | mlibc* | cos* | mbr* | ironclad* )
+	| domain* \
+	| dragonfly* \
+	| drops* \
+	| ebmon* \
+	| ecoff* \
+	| ekkobsd* \
+	| emscripten* \
+	| emx* \
+	| es* \
+	| fiwix* \
+	| freebsd* \
+	| fuchsia* \
+	| genix* \
+	| genode* \
+	| glidix* \
+	| gnu* \
+	| go32* \
+	| haiku* \
+	| hcos* \
+	| hiux* \
+	| hms* \
+	| hpux* \
+	| ieee* \
+	| interix* \
+	| ios* \
+	| iris* \
+	| irix* \
+	| ironclad* \
+	| isc* \
+	| its* \
+	| l4re* \
+	| libertybsd* \
+	| lites* \
+	| lnews* \
+	| luna* \
+	| lynxos* \
+	| mach* \
+	| macos* \
+	| magic* \
+	| mbr* \
+	| midipix* \
+	| midnightbsd* \
+	| mingw32* \
+	| mingw64* \
+	| minix* \
+	| mint* \
+	| mirbsd* \
+	| mks* \
+	| mlibc* \
+	| mmixware* \
+	| mon960* \
+	| morphos* \
+	| moss* \
+	| moxiebox* \
+	| mpeix* \
+	| mpw* \
+	| msdos* \
+	| msys* \
+	| mvs* \
+	| nacl* \
+	| netbsd* \
+	| netware* \
+	| newsos* \
+	| nextstep* \
+	| nindy* \
+	| nonstopux* \
+	| nova* \
+	| nsk* \
+	| nucleus* \
+	| nx6 \
+	| nx7 \
+	| oabi* \
+	| ohos* \
+	| onefs* \
+	| openbsd* \
+	| openedition* \
+	| openstep* \
+	| os108* \
+	| os2* \
+	| os400* \
+	| os68k* \
+	| os9* \
+	| ose* \
+	| osf* \
+	| oskit* \
+	| osx* \
+	| palmos* \
+	| phoenix* \
+	| plan9* \
+	| powermax* \
+	| powerunix* \
+	| proelf* \
+	| psos* \
+	| psp* \
+	| ptx* \
+	| pw32* \
+	| qnx* \
+	| rdos* \
+	| redox* \
+	| rhapsody* \
+	| riscix* \
+	| riscos* \
+	| rtems* \
+	| rtmk* \
+	| rtu* \
+	| scout* \
+	| secbsd* \
+	| sei* \
+	| serenity* \
+	| sim* \
+	| skyos* \
+	| solaris* \
+	| solidbsd* \
+	| sortix* \
+	| storm-chaos* \
+	| sunos \
+	| sunos[34]* \
+	| superux* \
+	| syllable* \
+	| sym* \
+	| sysv* \
+	| tenex* \
+	| tirtos* \
+	| toppers* \
+	| tops10* \
+	| tops20* \
+	| tpf* \
+	| tvos* \
+	| twizzler* \
+	| uclinux* \
+	| udi* \
+	| udk* \
+	| ultrix* \
+	| unicos* \
+	| uniplus* \
+	| unleashed* \
+	| unos* \
+	| uwin* \
+	| uxpv* \
+	| v88r* \
+	|*vms* \
+	| vos* \
+	| vsta* \
+	| vxsim* \
+	| vxworks* \
+	| wasi* \
+	| watchos* \
+	| wince* \
+	| windiss* \
+	| windows* \
+	| winnt* \
+	| xenix* \
+	| xray* \
+	| zephyr* \
+	| zvmoe* )
 		;;
 	# This one is extra strict with allowed versions
 	sco3.2v2 | sco3.2v[4-9]* | sco5v6*)
@@ -1829,9 +2210,9 @@ esac
 case $kernel-$os-$obj in
 	linux-gnu*- | linux-android*- | linux-dietlibc*- | linux-llvm*- \
 		    | linux-mlibc*- | linux-musl*- | linux-newlib*- \
-		    | linux-relibc*- | linux-uclibc*- )
+		    | linux-relibc*- | linux-uclibc*- | linux-ohos*- )
 		;;
-	uclinux-uclibc*- )
+	uclinux-uclibc*- | uclinux-gnu*- )
 		;;
 	managarm-mlibc*- | managarm-kernel*- )
 		;;
@@ -1856,7 +2237,7 @@ case $kernel-$os-$obj in
 		echo "Invalid configuration '$1': '$os' needs 'windows'." 1>&2
 		exit 1
 		;;
-	kfreebsd*-gnu*- | kopensolaris*-gnu*-)
+	kfreebsd*-gnu*- | knetbsd*-gnu*- | netbsd*-gnu*- | kopensolaris*-gnu*-)
 		;;
 	vxworks-simlinux- | vxworks-simwindows- | vxworks-spe-)
 		;;
@@ -1864,6 +2245,8 @@ case $kernel-$os-$obj in
 		;;
 	os2-emx-)
 		;;
+	rtmk-nova-)
+		;;
 	*-eabi*- | *-gnueabi*-)
 		;;
 	none--*)
@@ -1890,7 +2273,7 @@ case $vendor in
 			*-riscix*)
 				vendor=acorn
 				;;
-			*-sunos*)
+			*-sunos* | *-solaris*)
 				vendor=sun
 				;;
 			*-cnk* | *-aix*)

configure

@@ -1,6 +1,6 @@
 #! /bin/sh
 # Guess values for system-dependent variables and create Makefiles.
-# Generated by GNU Autoconf 2.72 for libpng 1.6.47.
+# Generated by GNU Autoconf 2.72 for libpng 1.6.51.git.
 #
 # Report bugs to <png-mng-implement@lists.sourceforge.net>.
 #
@@ -614,8 +614,8 @@ MAKEFLAGS=
 # Identity of this package.
 PACKAGE_NAME='libpng'
 PACKAGE_TARNAME='libpng'
-PACKAGE_VERSION='1.6.47'
+PACKAGE_VERSION='1.6.51.git'
-PACKAGE_STRING='libpng 1.6.47'
+PACKAGE_STRING='libpng 1.6.51.git'
 PACKAGE_BUGREPORT='png-mng-implement@lists.sourceforge.net'
 PACKAGE_URL=''
 
@@ -656,6 +656,8 @@ ac_subst_vars='am__EXEEXT_FALSE
 am__EXEEXT_TRUE
 LTLIBOBJS
 LIBOBJS
+PNG_RISCV_RVV_FALSE
+PNG_RISCV_RVV_TRUE
 PNG_LOONGARCH_LSX_FALSE
 PNG_LOONGARCH_LSX_TRUE
 PNG_POWERPC_VSX_FALSE
@@ -858,6 +860,7 @@ enable_mips_mmi
 enable_intel_sse
 enable_powerpc_vsx
 enable_loongarch_lsx
+enable_riscv_rvv
 '
       ac_precious_vars='build_alias
 host_alias
@@ -1421,7 +1424,7 @@ if test "$ac_init_help" = "long"; then
   # Omit some internal or obsolete options to make the list less imposing.
   # This message is too long to be a string in the A/UX 3.1 sh.
   cat <<_ACEOF
-'configure' configures libpng 1.6.47 to adapt to many kinds of systems.
+'configure' configures libpng 1.6.51.git to adapt to many kinds of systems.
 
 Usage: $0 [OPTION]... [VAR=VALUE]...
 
@@ -1492,7 +1495,7 @@ fi
 
 if test -n "$ac_init_help"; then
   case $ac_init_help in
-     short | recursive ) echo "Configuration of libpng 1.6.47:";;
+     short | recursive ) echo "Configuration of libpng 1.6.51.git:";;
    esac
   cat <<\_ACEOF
 
@@ -1590,6 +1593,12 @@ Optional Features:
                           no/off: disable the optimizations; yes/on: turn on
                           unconditionally. If not specified: determined by the
                           compiler.
+  --enable-riscv-rvv    Enable RISC-V Vector 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. If not specified: determined by the
+                          compiler.
 
 Optional Packages:
   --with-PACKAGE[=ARG]    use PACKAGE [ARG=yes]
@@ -1689,7 +1698,7 @@ fi
 test -n "$ac_init_help" && exit $ac_status
 if $ac_init_version; then
   cat <<\_ACEOF
-libpng configure 1.6.47
+libpng configure 1.6.51.git
 generated by GNU Autoconf 2.72
 
 Copyright (C) 2023 Free Software Foundation, Inc.
@@ -1952,7 +1961,7 @@ cat >config.log <<_ACEOF
 This file contains any messages produced by compilers while
 running configure, to aid debugging if configure makes a mistake.
 
-It was created by libpng $as_me 1.6.47, which was
+It was created by libpng $as_me 1.6.51.git, which was
 generated by GNU Autoconf 2.72.  Invocation command line was
 
   $ $0$ac_configure_args_raw
@@ -2733,7 +2742,7 @@ ac_compiler_gnu=$ac_cv_c_compiler_gnu
 # dist-xz requires automake 1.11 or later
 # 1.12.2 fixes a security issue in 1.11.2 and 1.12.1
 # 1.13 is required for parallel tests
-am__api_version='1.17'
+am__api_version='1.18'
 
 
 
@@ -3003,10 +3012,14 @@ am_lf='
 '
 case `pwd` in
   *[\\\"\#\$\&\'\`$am_lf]*)
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
     as_fn_error $? "unsafe absolute working directory name" "$LINENO" 5;;
 esac
 case $srcdir in
   *[\\\"\#\$\&\'\`$am_lf\ \	]*)
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
     as_fn_error $? "unsafe srcdir value: '$srcdir'" "$LINENO" 5;;
 esac
 
@@ -3433,7 +3446,7 @@ fi
 
 # Define the identity of the package.
  PACKAGE='libpng'
- VERSION='1.6.47'
+ VERSION='1.6.51.git'
 
 
 printf "%s\n" "#define PACKAGE \"$PACKAGE\"" >>confdefs.h
@@ -3471,9 +3484,133 @@ AMTAR='$${TAR-tar}'
 
 
 # We'll loop over all known methods to create a tar archive until one works.
-_am_tools='gnutar  pax cpio none'
+_am_tools='gnutar plaintar pax cpio none'
 
-am__tar='$${TAR-tar} chof - "$$tardir"' am__untar='$${TAR-tar} xf -'
+# The POSIX 1988 'ustar' format is defined with fixed-size fields.
+      # There is notably a 21 bits limit for the UID and the GID.  In fact,
+      # the 'pax' utility can hang on bigger UID/GID (see automake bug#8343
+      # and bug#13588).
+      am_max_uid=2097151 # 2^21 - 1
+      am_max_gid=$am_max_uid
+      # The $UID and $GID variables are not portable, so we need to resort
+      # to the POSIX-mandated id(1) utility.  Errors in the 'id' calls
+      # below are definitely unexpected, so allow the users to see them
+      # (that is, avoid stderr redirection).
+      am_uid=`id -u || echo unknown`
+      am_gid=`id -g || echo unknown`
+      { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether UID '$am_uid' is supported by ustar format" >&5
+printf %s "checking whether UID '$am_uid' is supported by ustar format... " >&6; }
+      if test x$am_uid = xunknown; then
+        { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: ancient id detected; assuming current UID is ok, but dist-ustar might not work" >&5
+printf "%s\n" "$as_me: WARNING: ancient id detected; assuming current UID is ok, but dist-ustar might not work" >&2;}
+      elif test $am_uid -le $am_max_uid; then
+        { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+printf "%s\n" "yes" >&6; }
+      else
+        { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+        _am_tools=none
+      fi
+      { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether GID '$am_gid' is supported by ustar format" >&5
+printf %s "checking whether GID '$am_gid' is supported by ustar format... " >&6; }
+      if test x$gm_gid = xunknown; then
+        { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: ancient id detected; assuming current GID is ok, but dist-ustar might not work" >&5
+printf "%s\n" "$as_me: WARNING: ancient id detected; assuming current GID is ok, but dist-ustar might not work" >&2;}
+      elif test $am_gid -le $am_max_gid; then
+        { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+printf "%s\n" "yes" >&6; }
+      else
+        { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+        _am_tools=none
+      fi
+
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking how to create a ustar tar archive" >&5
+printf %s "checking how to create a ustar tar archive... " >&6; }
+
+  # Go ahead even if we have the value already cached.  We do so because we
+  # need to set the values for the 'am__tar' and 'am__untar' variables.
+  _am_tools=${am_cv_prog_tar_ustar-$_am_tools}
+
+  for _am_tool in $_am_tools; do
+    case $_am_tool in
+    gnutar)
+      for _am_tar in tar gnutar gtar; do
+        { echo "$as_me:$LINENO: $_am_tar --version" >&5
+   ($_am_tar --version) >&5 2>&5
+   ac_status=$?
+   echo "$as_me:$LINENO: \$? = $ac_status" >&5
+   (exit $ac_status); } && break
+      done
+      am__tar="$_am_tar --format=ustar -chf - "'"$$tardir"'
+      am__tar_="$_am_tar --format=ustar -chf - "'"$tardir"'
+      am__untar="$_am_tar -xf -"
+      ;;
+    plaintar)
+      # Must skip GNU tar: if it does not support --format= it doesn't create
+      # ustar tarball either.
+      (tar --version) >/dev/null 2>&1 && continue
+      am__tar='tar chf - "$$tardir"'
+      am__tar_='tar chf - "$tardir"'
+      am__untar='tar xf -'
+      ;;
+    pax)
+      am__tar='pax -L -x ustar -w "$$tardir"'
+      am__tar_='pax -L -x ustar -w "$tardir"'
+      am__untar='pax -r'
+      ;;
+    cpio)
+      am__tar='find "$$tardir" -print | cpio -o -H ustar -L'
+      am__tar_='find "$tardir" -print | cpio -o -H ustar -L'
+      am__untar='cpio -i -H ustar -d'
+      ;;
+    none)
+      am__tar=false
+      am__tar_=false
+      am__untar=false
+      ;;
+    esac
+
+    # If the value was cached, stop now.  We just wanted to have am__tar
+    # and am__untar set.
+    test -n "${am_cv_prog_tar_ustar}" && break
+
+    # tar/untar a dummy directory, and stop if the command works.
+    rm -rf conftest.dir
+    mkdir conftest.dir
+    echo GrepMe > conftest.dir/file
+    { echo "$as_me:$LINENO: tardir=conftest.dir && eval $am__tar_ >conftest.tar" >&5
+   (tardir=conftest.dir && eval $am__tar_ >conftest.tar) >&5 2>&5
+   ac_status=$?
+   echo "$as_me:$LINENO: \$? = $ac_status" >&5
+   (exit $ac_status); }
+    rm -rf conftest.dir
+    if test -s conftest.tar; then
+      { echo "$as_me:$LINENO: $am__untar <conftest.tar" >&5
+   ($am__untar <conftest.tar) >&5 2>&5
+   ac_status=$?
+   echo "$as_me:$LINENO: \$? = $ac_status" >&5
+   (exit $ac_status); }
+      { echo "$as_me:$LINENO: cat conftest.dir/file" >&5
+   (cat conftest.dir/file) >&5 2>&5
+   ac_status=$?
+   echo "$as_me:$LINENO: \$? = $ac_status" >&5
+   (exit $ac_status); }
+      grep GrepMe conftest.dir/file >/dev/null 2>&1 && break
+    fi
+  done
+  rm -rf conftest.dir
+
+  if test ${am_cv_prog_tar_ustar+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) am_cv_prog_tar_ustar=$_am_tool ;;
+esac
+fi
+
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $am_cv_prog_tar_ustar" >&5
+printf "%s\n" "$am_cv_prog_tar_ustar" >&6; }
 
 
 
@@ -3528,10 +3665,10 @@ fi
 
 
 
-PNGLIB_VERSION=1.6.47
+PNGLIB_VERSION=1.6.51.git
 PNGLIB_MAJOR=1
 PNGLIB_MINOR=6
-PNGLIB_RELEASE=47
+PNGLIB_RELEASE=51
 
 
 
@@ -4611,7 +4748,10 @@ _ACEOF
       break
     fi
   done
-  rm -f core conftest*
+  # aligned with autoconf, so not including core; see bug#72225.
+  rm -f -r a.out a.exe b.out conftest.$ac_ext conftest.$ac_objext \
+    conftest.dSYM conftest1.$ac_ext conftest1.$ac_objext conftest1.dSYM \
+    conftest2.$ac_ext conftest2.$ac_objext conftest2.dSYM
   unset am_i ;;
 esac
 fi
@@ -15156,6 +15296,10 @@ printf "%s\n" "#define PNG_INTEL_SSE_OPT 0" >>confdefs.h
 
 printf "%s\n" "#define PNG_LOONGARCH_LSX_OPT 0" >>confdefs.h
 
+         enable_riscv_rvv=no
+
+printf "%s\n" "#define PNG_RISCV_RVV_OPT 0" >>confdefs.h
+
          ;;
       *)
          # allow enabling hardware optimization on any system:
@@ -15193,6 +15337,12 @@ printf "%s\n" "#define PNG_POWERPC_VSX_OPT 2" >>confdefs.h
 
 printf "%s\n" "#define PNG_LOONGARCH_LSX_OPT 1" >>confdefs.h
 
+              ;;
+            riscv64)
+              enable_riscv_rvv=yes
+
+printf "%s\n" "#define PNG_RISCV_RVV_OPT 2" >>confdefs.h
+
               ;;
          esac
          ;;
@@ -15550,6 +15700,97 @@ else
 fi
 
 
+# RISC-V
+# ======
+#
+# RISC-V Vector support.
+
+# Check whether --enable-riscv-rvv was given.
+if test ${enable_riscv_rvv+y}
+then :
+  enableval=$enable_riscv_rvv; case "$enableval" in
+      no|off)
+         # disable the default enabling on __riscv systems:
+
+printf "%s\n" "#define PNG_RISCV_RVV_OPT 0" >>confdefs.h
+
+         # Prevent inclusion of the platform-specific files below:
+         enable_riscv_rvv=no ;;
+      yes|on)
+
+printf "%s\n" "#define PNG_RISCV_RVV_OPT 2" >>confdefs.h
+
+         { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: --enable-riscv-rvv:
+            if you want the optimizations pass e.g. '-march=rv64gv1p0' to the compiler." >&5
+printf "%s\n" "$as_me: WARNING: --enable-riscv-rvv:
+            if you want the optimizations pass e.g. '-march=rv64gv1p0' to the compiler." >&2;};;
+      *)
+         as_fn_error $? "--enable-riscv-rvv=${enable_riscv_rvv}: invalid value" "$LINENO" 5
+   esac
+fi
+
+
+if test "$enable_riscv_rvv" != "no" &&
+   case "$host_cpu" in
+      riscv64) : ;;
+      *)    test "$enable_riscv_rvv" != '' ;;
+   esac
+then
+   compiler_support_riscv_rvv=no
+   { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether to use RISC-V RVV intrinsics" >&5
+printf %s "checking whether to use RISC-V RVV intrinsics... " >&6; }
+
+   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+#include <riscv_vector.h>
+#include <asm/hwcap.h>
+#ifndef COMPAT_HWCAP_ISA_V /* added in linux-6.5 */
+#error "COMPAT_HWCAP_ISA_V is not available"
+#endif
+int main() {
+   const float src[] = { 0.0f, 0.0f, 0.0f, 0.0f };
+   uint64_t ptr[2] = {0x0908060504020100, 0xFFFFFFFF0E0D0C0A};
+   vuint8m1_t a = __riscv_vreinterpret_v_u64m1_u8m1(__riscv_vle64_v_u64m1(ptr, 2));
+   vfloat32m1_t val = __riscv_vle32_v_f32m1((const float*)(src), 4);
+   return (int)__riscv_vfmv_f_s_f32m1_f32(val);
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"
+then :
+  compiler_support_riscv_rvv=yes
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
+   { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $compiler_support_riscv_rvv" >&5
+printf "%s\n" "$compiler_support_riscv_rvv" >&6; }
+   if test "$compiler_support_riscv_rvv" = "yes"; then
+
+printf "%s\n" "#define PNG_RISCV_RVV_OPT 1" >>confdefs.h
+
+   else
+      { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: Compiler does not support riscv rvv." >&5
+printf "%s\n" "$as_me: WARNING: Compiler does not support riscv rvv." >&2;}
+   fi
+fi
+
+# Add RISC-V-specific files to all builds where $host_cpu is riscv ('riscv64')
+# or where RISC-V optimizations were explicitly requested (this allows a fallback
+# if a future host CPU does not match 'riscv64')
+
+ if test "$enable_riscv_rvv" != "no" &&
+    test "$compiler_support_riscv_rvv" = "yes" &&
+    case "$host_cpu" in
+      riscv64) : ;;
+      *)    test "$compiler_support_riscv_rvv" != '' ;;
+    esac; then
+  PNG_RISCV_RVV_TRUE=
+  PNG_RISCV_RVV_FALSE='#'
+else
+  PNG_RISCV_RVV_TRUE='#'
+  PNG_RISCV_RVV_FALSE=
+fi
+
+
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: Extra options for compiler: $PNG_COPTS" >&5
 printf "%s\n" "$as_me: Extra options for compiler: $PNG_COPTS" >&6;}
 
@@ -15772,6 +16013,10 @@ if test -z "${PNG_LOONGARCH_LSX_TRUE}" && test -z "${PNG_LOONGARCH_LSX_FALSE}";
   as_fn_error $? "conditional \"PNG_LOONGARCH_LSX\" was never defined.
 Usually this means the macro was only invoked conditionally." "$LINENO" 5
 fi
+if test -z "${PNG_RISCV_RVV_TRUE}" && test -z "${PNG_RISCV_RVV_FALSE}"; then
+  as_fn_error $? "conditional \"PNG_RISCV_RVV\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
 
 : "${CONFIG_STATUS=./config.status}"
 ac_write_fail=0
@@ -16165,7 +16410,7 @@ cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
 # report actual input values of CONFIG_FILES etc. instead of their
 # values after options handling.
 ac_log="
-This file was extended by libpng $as_me 1.6.47, which was
+This file was extended by libpng $as_me 1.6.51.git, which was
 generated by GNU Autoconf 2.72.  Invocation command line was
 
   CONFIG_FILES    = $CONFIG_FILES
@@ -16233,7 +16478,7 @@ ac_cs_config_escaped=`printf "%s\n" "$ac_cs_config" | sed "s/^ //; s/'/'\\\\\\\\
 cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
 ac_cs_config='$ac_cs_config_escaped'
 ac_cs_version="\\
-libpng config.status 1.6.47
+libpng config.status 1.6.51.git
 configured by $0, generated by GNU Autoconf 2.72,
   with options \\"\$ac_cs_config\\"
 

configure.ac

@@ -25,7 +25,7 @@ AC_PREREQ([2.68])
 
 dnl Version number stuff here:
 
-AC_INIT([libpng],[1.6.47],[png-mng-implement@lists.sourceforge.net])
+AC_INIT([libpng],[1.6.51.git],[png-mng-implement@lists.sourceforge.net])
 AC_CONFIG_MACRO_DIR([scripts/autoconf])
 
 # libpng does not follow GNU file name conventions (hence 'foreign')
@@ -46,10 +46,10 @@ dnl automake, so the following is not necessary (and is not defined anyway):
 dnl AM_PREREQ([1.11.2])
 dnl stop configure from automagically running automake
 
-PNGLIB_VERSION=1.6.47
+PNGLIB_VERSION=1.6.51.git
 PNGLIB_MAJOR=1
 PNGLIB_MINOR=6
-PNGLIB_RELEASE=47
+PNGLIB_RELEASE=51
 
 dnl End of version number stuff
 
@@ -343,6 +343,9 @@ AC_ARG_ENABLE([hardware-optimizations],
          enable_loongarch_lsx=no
          AC_DEFINE([PNG_LOONGARCH_LSX_OPT], [0],
            [Disable LOONGARCH_LSX optimizations])
+         enable_riscv_rvv=no
+         AC_DEFINE([PNG_RISCV_RVV_OPT], [0],
+           [Disable RISC-V Vector optimizations])
          ;;
       *)
          # allow enabling hardware optimization on any system:
@@ -375,6 +378,11 @@ AC_ARG_ENABLE([hardware-optimizations],
               AC_DEFINE([PNG_LOONGARCH_LSX_OPT], [1],
                 [Enable LOONGARCH_LSX optimizations])
               ;;
+            riscv64)
+              enable_riscv_rvv=yes
+              AC_DEFINE([PNG_RISCV_RVV_OPT], [2],
+                [Enable RISC-V Vector optimizations])
+              ;;
          esac
          ;;
    esac])
@@ -661,6 +669,76 @@ AM_CONDITIONAL([PNG_LOONGARCH_LSX],
       *)    test "$enable_loongarch_lsx" != '' ;;
     esac])
 
+# RISC-V
+# ======
+#
+# RISC-V Vector support.
+
+AC_ARG_ENABLE([riscv-rvv],
+AS_HELP_STRING([[[--enable-riscv-rvv]]],
+      [Enable RISC-V Vector 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. If not specified: determined by the compiler.]),
+   [case "$enableval" in
+      no|off)
+         # disable the default enabling on __riscv systems:
+         AC_DEFINE([PNG_RISCV_RVV_OPT], [0],
+                   [Disable RISC-V Vector optimizations])
+         # Prevent inclusion of the platform-specific files below:
+         enable_riscv_rvv=no ;;
+      yes|on)
+         AC_DEFINE([PNG_RISCV_RVV_OPT], [2],
+                   [Enable RISC-V Vector optimizations])
+         AC_MSG_WARN([--enable-riscv-rvv:]
+            [if you want the optimizations pass e.g. '-march=rv64gv1p0' to the compiler.]);;
+      *)
+         AC_MSG_ERROR([--enable-riscv-rvv=${enable_riscv_rvv}: invalid value])
+   esac])
+
+if test "$enable_riscv_rvv" != "no" &&
+   case "$host_cpu" in
+      riscv64) : ;;
+      *)    test "$enable_riscv_rvv" != '' ;;
+   esac
+then
+   compiler_support_riscv_rvv=no
+   AC_MSG_CHECKING(whether to use RISC-V RVV intrinsics)
+
+   AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
+#include <riscv_vector.h>
+#include <asm/hwcap.h>
+#ifndef COMPAT_HWCAP_ISA_V /* added in linux-6.5 */
+#error "COMPAT_HWCAP_ISA_V is not available"
+#endif
+int main() {
+   const float src[] = { 0.0f, 0.0f, 0.0f, 0.0f };
+   uint64_t ptr[2] = {0x0908060504020100, 0xFFFFFFFF0E0D0C0A};
+   vuint8m1_t a = __riscv_vreinterpret_v_u64m1_u8m1(__riscv_vle64_v_u64m1(ptr, 2));
+   vfloat32m1_t val = __riscv_vle32_v_f32m1((const float*)(src), 4);
+   return (int)__riscv_vfmv_f_s_f32m1_f32(val);
+}]])],compiler_support_riscv_rvv=yes)
+   AC_MSG_RESULT($compiler_support_riscv_rvv)
+   if test "$compiler_support_riscv_rvv" = "yes"; then
+      AC_DEFINE([PNG_RISCV_RVV_OPT], [1],
+                [Enable RISCV RVV optimizations])
+   else
+      AC_MSG_WARN([Compiler does not support riscv rvv.])
+   fi
+fi
+
+# Add RISC-V-specific files to all builds where $host_cpu is riscv ('riscv64')
+# or where RISC-V optimizations were explicitly requested (this allows a fallback
+# if a future host CPU does not match 'riscv64')
+
+AM_CONDITIONAL([PNG_RISCV_RVV],
+   [test "$enable_riscv_rvv" != "no" &&
+    test "$compiler_support_riscv_rvv" = "yes" &&
+    case "$host_cpu" in
+      riscv64) : ;;
+      *)    test "$compiler_support_riscv_rvv" != '' ;;
+    esac])
+
 AC_MSG_NOTICE([[Extra options for compiler: $PNG_COPTS]])
 
 # Config files, substituting as above

contrib/conftest/read-full.dfa

@@ -0,0 +1,13 @@
+# read-full.dfa
+#  Build time configuration of libpng
+#
+# Author: John Bowler
+# Copyright: (c) John Bowler, 2025
+# 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 no write support and full read support.
+#
+option WRITE off

contrib/conftest/write-full.dfa

@@ -0,0 +1,13 @@
+# write-full.dfa
+#  Build time configuration of libpng
+#
+# Author: John Bowler
+# Copyright: (c) John Bowler, 2025
+# 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 no read support and full write support.
+#
+option READ off

contrib/examples/.clang-format

@@ -0,0 +1,143 @@
+---
+Language: Cpp
+AccessModifierOffset: -3
+AlignAfterOpenBracket: Align
+AlignArrayOfStructures: None
+AlignConsecutiveAssignments:
+  Enabled: false
+AlignConsecutiveBitFields:
+  Enabled: false
+AlignConsecutiveDeclarations:
+  Enabled: false
+AlignConsecutiveMacros:
+  Enabled: false
+AlignConsecutiveShortCaseStatements:
+  Enabled: false
+AlignEscapedNewlines: DontAlign
+AlignOperands: false
+AlignTrailingComments:
+  Kind: Never
+  OverEmptyLines: 0
+AllowAllArgumentsOnNextLine: true
+AllowAllParametersOfDeclarationOnNextLine: true
+AllowBreakBeforeNoexceptSpecifier: Never
+AllowShortBlocksOnASingleLine: Never
+AllowShortCaseExpressionOnASingleLine: true
+AllowShortCaseLabelsOnASingleLine: true
+AllowShortCompoundRequirementOnASingleLine: true
+AllowShortEnumsOnASingleLine: false
+AllowShortFunctionsOnASingleLine: None
+AllowShortIfStatementsOnASingleLine: Never
+AllowShortLambdasOnASingleLine: All
+AllowShortLoopsOnASingleLine: false
+AllowShortNamespacesOnASingleLine: false
+AlwaysBreakBeforeMultilineStrings: false
+BinPackArguments: true
+BinPackParameters: BinPack
+BitFieldColonSpacing: Both
+BraceWrapping:
+  AfterCaseLabel: true
+  AfterClass: true
+  AfterControlStatement: Always
+  AfterEnum: true
+  AfterExternBlock: false
+  AfterFunction: true
+  AfterNamespace: false
+  AfterObjCDeclaration: true
+  AfterStruct: true
+  AfterUnion: true
+  BeforeCatch: true
+  BeforeElse: true
+  BeforeLambdaBody: false
+  BeforeWhile: false
+  IndentBraces: false
+  SplitEmptyFunction: true
+  SplitEmptyRecord: true
+  SplitEmptyNamespace: true
+BreakAdjacentStringLiterals: true
+BreakAfterAttributes: Leave
+BreakAfterJavaFieldAnnotations: false
+BreakAfterReturnType: TopLevel
+BreakArrays: true
+BreakBeforeBinaryOperators: None
+BreakBeforeConceptDeclarations: Always
+BreakBeforeBraces: Custom
+BreakBeforeTernaryOperators: false
+BreakStringLiterals: false
+BreakTemplateDeclarations: MultiLine
+ColumnLimit: 79
+ContinuationIndentWidth: 3
+DerivePointerAlignment: true
+EmptyLineAfterAccessModifier: Never
+EmptyLineBeforeAccessModifier: LogicalBlock
+FixNamespaceComments: true
+IncludeBlocks: Preserve
+IndentAccessModifiers: false
+IndentCaseBlocks: true
+IndentCaseLabels: true
+IndentExportBlock: true
+IndentExternBlock: AfterExternBlock
+IndentGotoLabels: false
+IndentPPDirectives: None
+IndentRequiresClause: true
+IndentWidth: 3
+IndentWrappedFunctionNames: false
+KeepEmptyLines:
+  AtEndOfFile: false
+  AtStartOfBlock: false
+  AtStartOfFile: false
+KeepFormFeed: false
+MaxEmptyLinesToKeep: 2
+NamespaceIndentation: None
+PackConstructorInitializers: Never
+PointerAlignment: Left
+QualifierAlignment: Custom
+QualifierOrder: [static, inline, constexpr, const, volatile, restrict, type]
+ReferenceAlignment: Pointer
+ReflowComments: Never
+RequiresClausePosition: OwnLine
+RequiresExpressionIndentation: OuterScope
+SortIncludes: false
+SortUsingDeclarations: LexicographicNumeric
+SpaceAfterCStyleCast: false
+SpaceAfterLogicalNot: false
+SpaceAfterTemplateKeyword: true
+SpaceAroundPointerQualifiers: Default
+SpaceBeforeAssignmentOperators: true
+SpaceBeforeCaseColon: false
+SpaceBeforeCpp11BracedList: false
+SpaceBeforeCtorInitializerColon: true
+SpaceBeforeInheritanceColon: true
+SpaceBeforeJsonColon: false
+SpaceBeforeParens: ControlStatements
+SpaceBeforeParensOptions:
+  AfterControlStatements: true
+  AfterFunctionDefinitionName: false
+  AfterFunctionDeclarationName: false
+  AfterOverloadedOperator: false
+  AfterPlacementOperator: true
+  AfterRequiresInClause: false
+  AfterRequiresInExpression: false
+  BeforeNonEmptyParentheses: false
+SpaceBeforeRangeBasedForLoopColon: true
+SpaceBeforeSquareBrackets: false
+SpaceInEmptyBlock: false
+SpacesBeforeTrailingComments: 1
+SpacesInAngles: Never
+SpacesInContainerLiterals: true
+SpacesInLineCommentPrefix:
+  Minimum: 1
+  Maximum: -1
+SpacesInParens: Never
+SpacesInParensOptions:
+  ExceptDoubleParentheses: false
+  InCStyleCasts: false
+  InConditionalStatements: false
+  InEmptyParentheses: false
+  Other: false
+SpacesInSquareBrackets: false
+Standard: Latest
+TabWidth: 8
+UseTab: Never
+WrapNamespaceBodyWithEmptyLines: Leave
+...

contrib/examples/iccfrompng.c

@@ -26,8 +26,9 @@
 
 #include <png.h>
 
-#if defined(PNG_READ_SUPPORTED) && defined(PNG_STDIO_SUPPORTED) && \
+#if !defined(PNG_iCCP_SUPPORTED) || !defined(PNG_READ_SUPPORTED)
-    defined (PNG_iCCP_SUPPORTED)
+#error This program requires libpng supporting the iCCP chunk and the read API
+#endif
 
 
 static int verbose = 1;
@@ -36,7 +37,8 @@ static png_byte no_profile[] = "no profile";
 static png_bytep
 extract(FILE *fp, png_uint_32 *proflen)
 {
-   png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,0,0,0);
+   png_structp png_ptr =
+      png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
    png_infop info_ptr = NULL;
    png_bytep result = NULL;
 
@@ -69,7 +71,7 @@ extract(FILE *fp, png_uint_32 *proflen)
       png_bytep profile;
 
       if (png_get_iCCP(png_ptr, info_ptr, &name, &compression_type, &profile,
-         proflen) & PNG_INFO_iCCP)
+                       proflen) & PNG_INFO_iCCP)
       {
          result = malloc(*proflen);
          if (result != NULL)
@@ -107,7 +109,7 @@ extract_one_file(const char *filename)
             const char *ep = strrchr(filename, '.');
 
             if (ep != NULL)
-               len = ep-filename;
+               len = ep - filename;
 
             else
                len = strlen(filename);
@@ -119,14 +121,14 @@ extract_one_file(const char *filename)
             FILE *of;
 
             memcpy(output, filename, len);
-            strcpy(output+len, ".icc");
+            strcpy(output + len, ".icc");
 
             of = fopen(output, "wb");
             if (of != NULL)
             {
                if (fwrite(profile, proflen, 1, of) == 1 &&
-                  fflush(of) == 0 &&
+                   fflush(of) == 0 &&
-                  fclose(of) == 0)
+                   fclose(of) == 0)
                {
                   if (verbose)
                      printf("%s -> %s\n", filename, output);
@@ -161,6 +163,9 @@ extract_one_file(const char *filename)
    else
       fprintf(stderr, "%s: could not open file\n", filename);
 
+   if (fp != NULL)
+      fclose(fp);
+
    return result;
 }
 
@@ -170,7 +175,7 @@ main(int argc, char **argv)
    int i;
    int extracted = 0;
 
-   for (i=1; i<argc; ++i)
+   for (i = 1; i < argc; ++i)
    {
       if (strcmp(argv[i], "-q") == 0)
          verbose = 0;
@@ -182,4 +187,3 @@ main(int argc, char **argv)
    /* Exit code is true if any extract succeeds */
    return extracted == 0;
 }
-#endif /* READ && STDIO && iCCP */

contrib/examples/pngpixel.c

@@ -15,8 +15,8 @@
  * images.  Normally you would call png_set_interlace_handling() to have libpng
  * deal with the interlace for you, but that obliges you to buffer half of the
  * image to assemble the interlaced rows.  In this code
- * png_set_interlace_handling() is not called and, instead, the code handles the
+ * png_set_interlace_handling() is not called and, instead, the code handles
- * interlace passes directly looking for the required pixel.
+ * the interlace passes directly looking for the required pixel.
  */
 #include <stdlib.h>
 #include <stdio.h>
@@ -27,34 +27,37 @@
  */
 #include "../../png.h"
 
-#if defined(PNG_READ_SUPPORTED) && defined(PNG_SEQUENTIAL_READ_SUPPORTED)
+#if !defined(PNG_READ_SUPPORTED) || !defined(PNG_SEQUENTIAL_READ_SUPPORTED)
+#error This program requires libpng supporting the read and sequential read API
+#endif
+
 
 /* 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,
-   unsigned int bit_depth, unsigned int channels)
+          unsigned int bit_depth, unsigned int channels)
 {
-   /* PNG images can be up to 2^31 pixels wide, but this means they can be up to
+   /* PNG images can be up to 2^31 pixels wide, which means they can be up to
-    * 2^37 bits wide (for a 64-bit pixel - the largest possible) and hence 2^34
+    * 2^37 bits wide (for a 64-bit pixel - the largest possible) and hence
-    * bytes wide.  Since the row fitted into memory, however, the following must
+    * 2^34 bytes wide.  Since the row fitted into memory, the following must
     * work:
     */
    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)(((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;
 
    /* PNG pixels are packed into bytes to put the first pixel in the highest
-    * bits of the byte and into two bytes for 16-bit values with the high 8 bits
+    * bits of the byte, and into two bytes for 16-bit values with the high
-    * first, so:
+    * 8 bits first, so:
     */
    switch (bit_depth)
    {
-      case 1: return (row[0] >> (7-bit_offset_lo)) & 0x01;
+      case 1: return (row[0] >> (7 - bit_offset_lo)) & 0x01;
-      case 2: return (row[0] >> (6-bit_offset_lo)) & 0x03;
+      case 2: return (row[0] >> (6 - bit_offset_lo)) & 0x03;
-      case 4: return (row[0] >> (4-bit_offset_lo)) & 0x0f;
+      case 4: return (row[0] >> (4 - bit_offset_lo)) & 0x0f;
       case 8: return row[0];
       case 16: return (row[0] << 8) + row[1];
       default:
@@ -71,7 +74,7 @@ component(png_const_bytep row, png_uint_32 x, unsigned int c,
  */
 static void
 print_pixel(png_structp png_ptr, png_infop info_ptr, png_const_bytep row,
-   png_uint_32 x)
+            png_uint_32 x)
 {
    unsigned int bit_depth = png_get_bit_depth(png_ptr, info_ptr);
 
@@ -92,22 +95,24 @@ print_pixel(png_structp png_ptr, png_infop info_ptr, png_const_bytep row,
             int num_palette = 0;
 
             if ((png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette) &
-               PNG_INFO_PLTE) && num_palette > 0 && palette != NULL)
+                 PNG_INFO_PLTE) &&
+                (num_palette > 0) &&
+                (palette != NULL))
             {
                png_bytep trans_alpha = NULL;
                int num_trans = 0;
                if ((png_get_tRNS(png_ptr, info_ptr, &trans_alpha, &num_trans,
-                  NULL) & PNG_INFO_tRNS) && num_trans > 0 &&
+                                 NULL) & PNG_INFO_tRNS) &&
-                  trans_alpha != NULL)
+                   (num_trans > 0) &&
+                   (trans_alpha != NULL))
                   printf("INDEXED %u = %d %d %d %d\n", index,
-                     palette[index].red, palette[index].green,
+                         palette[index].red, palette[index].green,
-                     palette[index].blue,
+                         palette[index].blue,
-                     index < num_trans ? trans_alpha[index] : 255);
+                         index < num_trans ? trans_alpha[index] : 255);
 
                else /* no transparency */
-                  printf("INDEXED %u = %d %d %d\n", index,
+                  printf("INDEXED %u = %d %d %d\n", index, palette[index].red,
-                     palette[index].red, palette[index].green,
+                         palette[index].green, palette[index].blue);
-                     palette[index].blue);
             }
 
             else
@@ -117,20 +122,20 @@ print_pixel(png_structp png_ptr, png_infop info_ptr, png_const_bytep row,
 
       case PNG_COLOR_TYPE_RGB:
          printf("RGB %u %u %u\n", component(row, x, 0, bit_depth, 3),
-            component(row, x, 1, bit_depth, 3),
+                component(row, x, 1, bit_depth, 3),
-            component(row, x, 2, bit_depth, 3));
+                component(row, x, 2, bit_depth, 3));
          return;
 
       case PNG_COLOR_TYPE_GRAY_ALPHA:
          printf("GRAY+ALPHA %u %u\n", component(row, x, 0, bit_depth, 2),
-            component(row, x, 1, bit_depth, 2));
+                component(row, x, 1, bit_depth, 2));
          return;
 
       case PNG_COLOR_TYPE_RGB_ALPHA:
          printf("RGBA %u %u %u %u\n", component(row, x, 0, bit_depth, 4),
-            component(row, x, 1, bit_depth, 4),
+                component(row, x, 1, bit_depth, 4),
-            component(row, x, 2, bit_depth, 4),
+                component(row, x, 2, bit_depth, 4),
-            component(row, x, 3, bit_depth, 4));
+                component(row, x, 3, bit_depth, 4));
          return;
 
       default:
@@ -138,7 +143,8 @@ print_pixel(png_structp png_ptr, png_infop info_ptr, png_const_bytep row,
    }
 }
 
-int main(int argc, const char **argv)
+int
+main(int argc, const char **argv)
 {
    /* This program uses the default, <setjmp.h> based, libpng error handling
     * mechanism, therefore any local variable that exists before the call to
@@ -146,7 +152,7 @@ int main(int argc, const char **argv)
     * be declared with 'volatile' to ensure that their values don't get
     * destroyed by longjmp:
     */
-   volatile int result = 1/*fail*/;
+   volatile int result = 1 /*fail*/;
 
    if (argc == 4)
    {
@@ -163,8 +169,8 @@ int main(int argc, const char **argv)
           * writes error messages to stderr.  Creating the png_struct is a
           * little tricky; just copy the following code.
           */
-         png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
+         png_structp png_ptr =
-            NULL, NULL, NULL);
+            png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
 
          if (png_ptr != NULL)
          {
@@ -184,11 +190,11 @@ int main(int argc, const char **argv)
                      compression_method, filter_method;
                   png_bytep row_tmp;
 
-                  /* Now associate the recently opened (FILE*) with the default
+                  /* Now associate the recently opened FILE object with the
-                   * libpng initialization functions.  Sometimes libpng is
+                   * default libpng initialization functions.  Sometimes libpng
-                   * compiled without stdio support (it can be difficult to do
+                   * is compiled without stdio support (it can be difficult to
-                   * in some environments); in that case you will have to write
+                   * do in some environments); in that case you will have to
-                   * your own read callback to read data from the (FILE*).
+                   * write your own read callback to read data from the stream.
                    */
                   png_init_io(png_ptr, f);
 
@@ -202,21 +208,21 @@ int main(int argc, const char **argv)
                    * space.  In this case png_malloc is used - it will not
                    * return if memory isn't available.
                    */
-                  row = png_malloc(png_ptr, png_get_rowbytes(png_ptr,
+                  row =
-                     info_ptr));
+                     png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr));
 
-                  /* To avoid the overhead of using a volatile auto copy row_tmp
+                  /* Avoid the overhead of using a volatile auto copy row_tmp
                    * to a local here - just use row for the png_free below.
                    */
                   row_tmp = row;
 
-                  /* All the information we need is in the header is returned by
+                  /* All the information we need is in the header returned by
-                   * png_get_IHDR, if this fails we can now use 'png_error' to
+                   * png_get_IHDR.  If this fails, we can use 'png_error' to
                    * signal the error and return control to the setjmp above.
                    */
                   if (png_get_IHDR(png_ptr, info_ptr, &width, &height,
-                     &bit_depth, &color_type, &interlace_method,
+                                   &bit_depth, &color_type, &interlace_method,
-                     &compression_method, &filter_method))
+                                   &compression_method, &filter_method))
                   {
                      int passes, pass;
 
@@ -242,7 +248,7 @@ int main(int argc, const char **argv)
                      /* Now read the pixels, pass-by-pass, row-by-row: */
                      png_start_read_image(png_ptr);
 
-                     for (pass=0; pass<passes; ++pass)
+                     for (pass = 0; pass < passes; ++pass)
                      {
                         png_uint_32 ystart, xstart, ystep, xstep;
                         png_uint_32 py;
@@ -299,19 +305,27 @@ int main(int argc, const char **argv)
                             * are, of course, much better ways of doing this
                             * than using a for loop:
                             */
-                           if (y == py) for (px = xstart, ppx = 0;
+                           if (y == py)
-                              px < width; px += xstep, ++ppx) if (x == px)
                            {
-                              /* 'ppx' is the index of the pixel in the row
+                              for (px = xstart, ppx = 0;
-                               * buffer.
+                                   px < width;
-                               */
+                                   px += xstep, ++ppx)
-                              print_pixel(png_ptr, info_ptr, row_tmp, ppx);
+                              {
+                                 if (x == px)
+                                 {
+                                    /* 'ppx' is the index of the pixel in the
+                                     * row buffer.
+                                     */
+                                    print_pixel(png_ptr, info_ptr, row_tmp,
+                                                ppx);
 
-                              /* Now terminate the loops early - we have
+                                    /* Now terminate the loops early - we have
-                               * found and handled the required data.
+                                     * found and handled the required data.
-                               */
+                                     */
-                              goto pass_loop_end;
+                                    goto pass_loop_end;
-                           } /* x loop */
+                                 } /* x loop */
+                              }
+                           }
                         } /* y loop */
                      } /* pass loop */
 
@@ -323,7 +337,6 @@ int main(int argc, const char **argv)
 
                   else
                      png_error(png_ptr, "pngpixel: png_get_IHDR failed");
-
                }
 
                else
@@ -349,7 +362,8 @@ int main(int argc, const char **argv)
             }
 
             else
-               fprintf(stderr, "pngpixel: out of memory allocating png_info\n");
+               fprintf(stderr,
+                       "pngpixel: out of memory allocating png_info\n");
 
             png_destroy_read_struct(&png_ptr, NULL, NULL);
          }
@@ -368,4 +382,3 @@ int main(int argc, const char **argv)
 
    return result;
 }
-#endif /* READ && SEQUENTIAL_READ */

contrib/examples/pngtopng.c

@@ -8,8 +8,8 @@
  * Read a PNG and write it out in a fixed format, using the 'simplified API'
  * that was introduced in libpng-1.6.0.
  *
- * This sample code is just the code from the top of 'example.c' with some error
+ * This sample code is just the code from 'example.c' with some error handling
- * handling added.  See example.c for more comments.
+ * added.  See example.c in the top-level libpng directory for more comments.
  */
 #include <stddef.h>
 #include <stdlib.h>
@@ -20,10 +20,15 @@
  * 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)
+#if !defined(PNG_SIMPLIFIED_READ_SUPPORTED) || \
+    !defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
+#error This program requires libpng supporting the simplified read/write API
+#endif
+
+
+int
+main(int argc, const char **argv)
 {
    int result = 1;
 
@@ -48,22 +53,22 @@ int main(int argc, const char **argv)
 
          if (buffer != NULL)
          {
-            if (png_image_finish_read(&image, NULL/*background*/, buffer,
+            if (png_image_finish_read(&image, NULL /*background*/, buffer,
-               0/*row_stride*/, NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP */))
+                                      0 /*row_stride*/, NULL /*colormap */))
             {
-               if (png_image_write_to_file(&image, argv[2],
+               if (png_image_write_to_file(
-                  0/*convert_to_8bit*/, buffer, 0/*row_stride*/,
+                      &image, argv[2], 0 /*convert_to_8bit*/, buffer,
-                  NULL/*colormap*/))
+                      0 /*row_stride*/, NULL /*colormap*/))
                   result = 0;
 
                else
                   fprintf(stderr, "pngtopng: write %s: %s\n", argv[2],
-                      image.message);
+                          image.message);
             }
 
             else
                fprintf(stderr, "pngtopng: read %s: %s\n", argv[1],
-                   image.message);
+                       image.message);
 
             free(buffer);
          }
@@ -71,7 +76,7 @@ int main(int argc, const char **argv)
          else
          {
             fprintf(stderr, "pngtopng: out of memory: %lu bytes\n",
-               (unsigned long)PNG_IMAGE_SIZE(image));
+                    (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
@@ -93,4 +98,3 @@ int main(int argc, const char **argv)
 
    return result;
 }
-#endif /* READ && WRITE */

contrib/examples/simpleover.c

@@ -6,9 +6,9 @@
  * 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
+ * information, and composite them together to produce one or more 16-bit
- * RGBA intermediates.  This involves doing the correct 'over' composition to
+ * linear RGBA intermediates.  This involves doing the 'over' compositing
- * combine the alpha channels and corresponding data.
+ * operation 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
@@ -28,8 +28,8 @@
  * 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
+ * be regarded as being layered one on top of the other with the first
- * on the command line) being at the bottom and the last on the top.
+ * (leftmost on the command line) being at the bottom and the last on the top.
  */
 #include <stddef.h>
 #include <stdlib.h>
@@ -44,54 +44,61 @@
  */
 #include "../../png.h"
 
-#ifdef PNG_SIMPLIFIED_READ_SUPPORTED
+#if !defined(PNG_SIMPLIFIED_READ_SUPPORTED)
+#error This program requires libpng supporting the simplified read API
+#endif
 
 #define sprite_name_chars 15
-struct sprite {
+struct sprite
-   FILE         *file;
+{
-   png_uint_16p  buffer;
+   FILE *file;
-   unsigned int  width;
+   png_uint_16p buffer;
-   unsigned int  height;
+   unsigned int width;
-   char          name[sprite_name_chars+1];
+   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) {
+int
+main(void)
+{
    double err = 0;
    unsigned int xerr = 0;
    unsigned int r = 32769;
+   unsigned int x = 0;
+
+   do
    {
-      unsigned int x = 0;
+      unsigned int t = x + (x >> 16) /*+ (x >> 31)*/ + r;
+      double v = x, errtest;
 
-      do {
+      if (t < x)
-         unsigned int t = x + (x >> 16) /*+ (x >> 31)*/ + r;
+      {
-         double v = x, errtest;
+         fprintf(stderr, "overflow: %u+%u -> %u\n", x, r, t);
+         return 1;
+      }
 
-         if (t < x) {
+      v /= 65535;
-            fprintf(stderr, "overflow: %u+%u -> %u\n", x, r, t);
+      errtest = v;
-            return 1;
+      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;
          }
-
+      }
-         v /= 65535;
+   } while (++x <= 65535U * 65535U);
-         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);
 
@@ -101,7 +108,7 @@ int main(void) {
 
 static void
 sprite_op(const struct sprite *sprite, int x_offset, int y_offset,
-   png_imagep image, const png_uint_16 *buffer)
+          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
@@ -112,8 +119,8 @@ sprite_op(const struct sprite *sprite, int x_offset, int y_offset,
    /* 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) &&
+   if ((y_offset < 0 || /*SAFE*/ (unsigned)y_offset < sprite->height) &&
-       (x_offset < 0 || (unsigned)/*SAFE*/x_offset < sprite->width))
+       (x_offset < 0 || /*SAFE*/ (unsigned)x_offset < sprite->width))
    {
       unsigned int y = 0;
 
@@ -130,7 +137,7 @@ sprite_op(const struct sprite *sprite, int x_offset, int y_offset,
          do
          {
             /* In and out are RGBA values, so: */
-            const png_uint_16 *in_pixel = buffer + (y * image->width + x)*4;
+            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
@@ -139,10 +146,10 @@ sprite_op(const struct sprite *sprite, int x_offset, int y_offset,
             if (in_alpha > 0)
             {
                png_uint_16 *out_pixel = sprite->buffer +
-                  ((y+y_offset) * sprite->width + (x+x_offset))*4;
+                  ((y + y_offset) * sprite->width + (x + x_offset)) * 4;
 
                /* This is the weight to apply to the output: */
-               in_alpha = 65535-in_alpha;
+               in_alpha = 65535 - in_alpha;
 
                if (in_alpha > 0)
                {
@@ -159,9 +166,9 @@ sprite_op(const struct sprite *sprite, int x_offset, int y_offset,
                    */
                   png_uint_32 tmp;
 
-#                 define compose(c)\
+#                 define compose(c) \
-                     tmp = out_pixel[c] * in_alpha;\
+                     tmp = out_pixel[c] * in_alpha; \
-                     tmp = (tmp + (tmp >> 16) + 32769) >> 16;\
+                     tmp = (tmp + (tmp >> 16) + 32769) >> 16; \
                      out_pixel[c] = tmp + in_pixel[c]
 
                   /* The following is very vectorizable... */
@@ -172,15 +179,15 @@ sprite_op(const struct sprite *sprite, int x_offset, int y_offset,
                }
 
                else
-                  out_pixel[0] = in_pixel[0],
+               {
-                  out_pixel[1] = in_pixel[1],
+                  out_pixel[0] = in_pixel[0];
-                  out_pixel[2] = in_pixel[2],
+                  out_pixel[1] = in_pixel[1];
+                  out_pixel[2] = in_pixel[2];
                   out_pixel[3] = in_pixel[3];
+               }
             }
-         }
+         } while (++x < image->width);
-         while (++x < image->width);
+      } while (++y < image->height);
-      }
-      while (++y < image->height);
    }
 }
 
@@ -224,9 +231,8 @@ create_sprite(struct sprite *sprite, int *argc, const char ***argv)
 
             if (buffer != NULL)
             {
-               if (png_image_finish_read(&image, NULL/*background*/, buffer,
+               if (png_image_finish_read(&image, NULL /*background*/, buffer,
-                  0/*row_stride*/,
+                                         0 /*row_stride*/, NULL /*colormap*/))
-                  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
@@ -245,14 +251,14 @@ create_sprite(struct sprite *sprite, int *argc, const char ***argv)
                {
                   free(buffer);
                   fprintf(stderr, "simpleover: read %s: %s\n", (*argv)[0],
-                      image.message);
+                          image.message);
                }
             }
 
             else
             {
                fprintf(stderr, "simpleover: out of memory: %lu bytes\n",
-                  (unsigned long)PNG_IMAGE_SIZE(image));
+                       (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
@@ -290,8 +296,9 @@ create_sprite(struct sprite *sprite, int *argc, const char ***argv)
       save.flags = PNG_IMAGE_FLAG_FAST;
       save.colormap_entries = 0;
 
-      if (png_image_write_to_stdio(&save, sprite->file, 1/*convert_to_8_bit*/,
+      if (png_image_write_to_stdio(&save, sprite->file, 1 /*convert_to_8_bit*/,
-          sprite->buffer, 0/*row_stride*/, NULL/*colormap*/))
+                                   sprite->buffer, 0 /*row_stride*/,
+                                   NULL /*colormap*/))
       {
          /* Success; the buffer is no longer needed: */
          free(sprite->buffer);
@@ -301,19 +308,20 @@ create_sprite(struct sprite *sprite, int *argc, const char ***argv)
 
       else
          fprintf(stderr, "simpleover: write sprite %s: %s\n", sprite->name,
-            save.message);
+                 save.message);
    }
 
    else
-      fprintf(stderr, "simpleover: sprite %s: could not allocate tmpfile: %s\n",
+      fprintf(stderr,
-         sprite->name, strerror(errno));
+              "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)
+           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
@@ -334,13 +342,13 @@ add_sprite(png_imagep output, png_bytep out_buf, struct sprite *sprite,
           * will fit.
           */
          if (x < 0 || y < 0 ||
-             (unsigned)/*SAFE*/x >= output->width ||
+             /*SAFE*/ (unsigned)x >= output->width ||
-             (unsigned)/*SAFE*/y >= output->height ||
+             /*SAFE*/ (unsigned)y >= output->height ||
-             sprite->width > output->width-x ||
+             sprite->width > output->width - x ||
-             sprite->height > output->height-y)
+             sprite->height > output->height - y)
          {
             fprintf(stderr, "simpleover: sprite %s @ (%d,%d) outside image\n",
-               sprite->name, x, y);
+                    sprite->name, x, y);
             /* Could just skip this, but for the moment it is an error */
             return 0; /* error */
          }
@@ -359,10 +367,10 @@ add_sprite(png_imagep output, png_bytep out_buf, struct sprite *sprite,
             {
                in.format = PNG_FORMAT_RGB; /* force compose */
 
-               if (png_image_finish_read(&in, NULL/*background*/,
+               if (png_image_finish_read(
-                  out_buf + (y*output->width + x)*3/*RGB*/,
+                      &in, NULL /*background*/,
-                  output->width*3/*row_stride*/,
+                      out_buf + (y * output->width + x) * 3 /*RGB*/,
-                  NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP*/))
+                      output->width * 3 /*row_stride*/, NULL /*colormap*/))
                {
                   ++*argv, --*argc;
                   continue;
@@ -371,7 +379,7 @@ add_sprite(png_imagep output, png_bytep out_buf, struct sprite *sprite,
 
             /* The read failed: */
             fprintf(stderr, "simpleover: add sprite %s: %s\n", sprite->name,
-                in.message);
+                    in.message);
             return 0; /* error */
          }
       }
@@ -379,7 +387,7 @@ add_sprite(png_imagep output, png_bytep out_buf, struct sprite *sprite,
       else
       {
          fprintf(stderr, "simpleover: --add='%s': invalid position %s\n",
-               sprite->name, (*argv)[0]);
+                 sprite->name, (*argv)[0]);
          return 0; /* error */
       }
    }
@@ -389,10 +397,10 @@ add_sprite(png_imagep output, png_bytep out_buf, struct sprite *sprite,
 
 static int
 simpleover_process(png_imagep output, png_bytep out_buf, int argc,
-   const char **argv)
+                   const char **argv)
 {
    int result = 1; /* success */
-#  define csprites 10/*limit*/
+#  define csprites 10 /*limit*/
 #  define str(a) #a
    int nsprites = 0;
    struct sprite sprites[csprites];
@@ -412,23 +420,25 @@ simpleover_process(png_imagep output, png_bytep out_buf, int argc,
             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",
+            n = sscanf(argv[0],
-                &sprites[nsprites].width, &sprites[nsprites].height,
+                       "--sprite=%u,%u,%" str(sprite_name_chars) "s%c",
-                sprites[nsprites].name, &tombstone);
+                       &sprites[nsprites].width, &sprites[nsprites].height,
+                       sprites[nsprites].name, &tombstone);
 
             if ((n == 2 || n == 3) &&
-                sprites[nsprites].width > 0 && sprites[nsprites].height > 0)
+                (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);
+                  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 = sizeof(png_uint_16[4]);
                buf_size *= sprites[nsprites].width;
                buf_size *= sprites[nsprites].height;
 
@@ -437,7 +447,7 @@ simpleover_process(png_imagep output, png_bytep out_buf, int argc,
                tmp /= sprites[nsprites].width;
                tmp /= sprites[nsprites].height;
 
-               if (tmp == sizeof (png_uint_16 [4]))
+               if (tmp == sizeof(png_uint_16[4]))
                {
                   sprites[nsprites].buffer = malloc(buf_size);
                   /* This buffer must be initialized to transparent: */
@@ -448,7 +458,7 @@ simpleover_process(png_imagep output, png_bytep out_buf, int argc,
                      sprites[nsprites].file = NULL;
                      ++argv, --argc;
 
-                     if (create_sprite(sprites+nsprites++, &argc, &argv))
+                     if (create_sprite(sprites + nsprites++, &argc, &argv))
                      {
                         result = 1; /* still ok */
                         continue;
@@ -466,7 +476,8 @@ simpleover_process(png_imagep output, png_bytep out_buf, int argc,
             else
             {
                fprintf(stderr, "simpleover: %s: invalid sprite (%u,%u)\n",
-                  argv[0], sprites[nsprites].width, sprites[nsprites].height);
+                       argv[0],
+                       sprites[nsprites].width, sprites[nsprites].height);
                break;
             }
          }
@@ -480,7 +491,7 @@ simpleover_process(png_imagep output, png_bytep out_buf, int argc,
 
       else if (strncmp(argv[0], "--add=", 6) == 0)
       {
-         const char *name = argv[0]+6;
+         const char *name = argv[0] + 6;
          int isprite = nsprites;
 
          ++argv, --argc;
@@ -489,7 +500,8 @@ simpleover_process(png_imagep output, png_bytep out_buf, int argc,
          {
             if (strcmp(sprites[isprite].name, name) == 0)
             {
-               if (!add_sprite(output, out_buf, sprites+isprite, &argc, &argv))
+               if (!add_sprite(output, out_buf, sprites + isprite,
+                               &argc, &argv))
                   goto out; /* error in add_sprite */
 
                break;
@@ -498,7 +510,8 @@ simpleover_process(png_imagep output, png_bytep out_buf, int argc,
 
          if (isprite < 0) /* sprite not found */
          {
-            fprintf(stderr, "simpleover: --add='%s': sprite not found\n", name);
+            fprintf(stderr, "simpleover: --add='%s': sprite not found\n",
+                    name);
             break;
          }
       }
@@ -526,7 +539,8 @@ out:
    return result;
 }
 
-int main(int argc, const char **argv)
+int
+main(int argc, const char **argv)
 {
    int result = 1; /* default to fail */
 
@@ -536,7 +550,7 @@ int main(int argc, const char **argv)
       const char *output = NULL;
       png_image image;
 
-      if (argc > 2 && argv[2][0] != '-'/*an operation*/)
+      if (argc > 2 && argv[2][0] != '-' /*an operation*/)
       {
          output = argv[2];
          argi = 3;
@@ -558,7 +572,7 @@ int main(int argc, const char **argv)
             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 */))
+                                      0 /*row_stride*/, NULL /*colormap*/))
             {
                /* At this point png_image_finish_read has cleaned up the
                 * allocated data in png_image, and only the buffer needs to be
@@ -566,22 +580,24 @@ int main(int argc, const char **argv)
                 *
                 * Perform the remaining operations:
                 */
-               if (simpleover_process(&image, buffer, argc-argi, argv+argi))
+               if (simpleover_process(&image, buffer,
+                                      argc - argi, argv + argi))
                {
                   /* Write the output: */
                   if ((output != NULL &&
-                       png_image_write_to_file(&image, output,
+                       png_image_write_to_file(
-                        0/*convert_to_8bit*/, buffer, 0/*row_stride*/,
+                          &image, output, 0 /*convert_to_8bit*/, buffer,
-                        NULL/*colormap*/)) ||
+                          0 /*row_stride*/, NULL /*colormap*/)) ||
                       (output == NULL &&
-                       png_image_write_to_stdio(&image, stdout,
+                       png_image_write_to_stdio(
-                        0/*convert_to_8bit*/, buffer, 0/*row_stride*/,
+                          &image, stdout, 0 /*convert_to_8bit*/, buffer,
-                        NULL/*colormap*/)))
+                          0 /*row_stride*/, NULL /*colormap*/)))
                      result = 0;
 
                   else
                      fprintf(stderr, "simpleover: write %s: %s\n",
-                        output == NULL ? "stdout" : output, image.message);
+                             output == NULL ? "stdout" : output,
+                             image.message);
                }
 
                /* else simpleover_process writes an error message */
@@ -589,7 +605,7 @@ int main(int argc, const char **argv)
 
             else
                fprintf(stderr, "simpleover: read %s: %s\n", argv[1],
-                   image.message);
+                       image.message);
 
             free(buffer);
          }
@@ -597,7 +613,7 @@ int main(int argc, const char **argv)
          else
          {
             fprintf(stderr, "simpleover: out of memory: %lu bytes\n",
-               (unsigned long)PNG_IMAGE_SIZE(image));
+                    (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
@@ -617,7 +633,8 @@ int main(int argc, const char **argv)
    else
    {
       /* Usage message */
-      fprintf(stderr,
+      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"
@@ -628,13 +645,13 @@ int main(int argc, const char **argv)
          "   --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"
+         "    For each sprite.png composite it is using a Porter-Duff 'Over'\n"
-         "     operation at offset (x,y) in the sprite (defaulting to (0,0)).\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"
+         "     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"
@@ -645,4 +662,3 @@ int main(int argc, const char **argv)
 
    return result;
 }
-#endif /* SIMPLIFIED_READ */

contrib/libtests/pngstest.c

@@ -595,7 +595,8 @@ newimage(Image *image)
    memset(image, 0, sizeof *image);
 }
 
-/* Reset the image to be read again - only needs to rewind the FILE* at present.
+/* Reset the image to be read again - only needs to rewind the FILE object at
+ * present.
  */
 static void
 resetimage(Image *image)

contrib/riscv-rvv/README

@@ -0,0 +1,85 @@
+OPERATING SYSTEM SPECIFIC RISC-V RVV DETECTION
+----------------------------------------------
+
+Detection of the ability to execute RISC-V Vector on a RISC-V 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
+riscv/riscv_init.c by setting the macro PNG_RISCV_RVV_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 riscv/riscv_init.o with the required macro
+definition.
+
+For any of this code to be used the RISC-V Vector code must be enabled and run
+time checks must be supported.  I.e.:
+
+#if PNG_RISCV_RVV_OPT > 0
+#ifdef PNG_RISCV_RVV_CHECK_SUPPORTED
+
+This is done in a 'configure' build by passing configure the argument:
+
+   --enable-riscv-rvv=check
+
+Apart from the basic Linux implementation in contrib/riscv-rvv/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_rvv(png_structp png_ptr);
+
+That function must return 1 if RISC-V Vector 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/riscv-rvv/linux.c

@@ -0,0 +1,36 @@
+/* contrib/riscv-rvv/linux.c
+ *
+ * Copyright (c) 2023 Google LLC
+ * Written by Dragoș Tiselice <dtiselice@google.com>, May 2023.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * SEE contrib/riscv-rvv/README before reporting bugs
+ *
+ * STATUS: SUPPORTED
+ * BUG REPORTS: png-mng-implement@sourceforge.net
+ *
+ * png_have_rvv implemented for Linux by looking for COMPAT_HWCAP_ISA_V
+ * via hardware capabilites API.
+ *
+ * This code is strict ANSI-C and is probably moderately portable; it does
+ * however use <stdio.h> and it assumes that /proc/cpuinfo is never localized.
+ */
+
+#if defined(__linux__)
+#include <asm/hwcap.h>
+#include <sys/auxv.h>
+#endif
+
+static int
+png_have_rvv() {
+#if defined(__linux__)
+   return getauxval (AT_HWCAP) & COMPAT_HWCAP_ISA_V ? 1 : 0;
+#else
+#pragma message(                                                               \
+   "warning: RISC-V Vector not supported for this platform")
+   return 0;
+#endif
+}

contrib/tools/pngfix.c

@@ -32,7 +32,7 @@
 #endif
 
 #if PNG_LIBPNG_VER < 10603 /* 1.6.3 */
-#  error "pngfix will not work with libpng prior to 1.6.3"
+#  error pngfix requires libpng version 1.6.3 or newer
 #endif
 
 #ifdef PNG_SETJMP_SUPPORTED
@@ -68,7 +68,7 @@
 #endif
 
 #ifndef PNG_MAXIMUM_INFLATE_WINDOW
-#  error "pngfix not supported in this libpng version"
+#  error pngfix requires libpng with PNG_MAXIMUM_INFLATE_WINDOW supported
 #endif
 
 #if ZLIB_VERNUM >= 0x1240

depcomp

@@ -1,9 +1,9 @@
 #! /bin/sh
 # depcomp - compile a program generating dependencies as side-effects
 
-scriptversion=2024-06-19.01; # UTC
+scriptversion=2025-06-18.21; # UTC
 
-# Copyright (C) 1999-2024 Free Software Foundation, Inc.
+# Copyright (C) 1999-2025 Free Software Foundation, Inc.
 
 # 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
@@ -784,9 +784,9 @@ exit 0
 # Local Variables:
 # mode: shell-script
 # sh-indentation: 2
-# eval: (add-hook 'before-save-hook 'time-stamp)
+# eval: (add-hook 'before-save-hook 'time-stamp nil t)
 # time-stamp-start: "scriptversion="
-# time-stamp-format: "%:y-%02m-%02d.%02H"
+# time-stamp-format: "%Y-%02m-%02d.%02H"
 # time-stamp-time-zone: "UTC0"
 # time-stamp-end: "; # UTC"
 # End:

example.c

@@ -2,7 +2,7 @@
 
 /* example.c - an example of using libpng
  *
- * Maintained 2018-2024 Cosmin Truta
+ * Maintained 2018-2025 Cosmin Truta
  * Maintained 1998-2016 Glenn Randers-Pehrson
  * Maintained 1996-1997 Andreas Dilger
  * Written 1995-1996 Guy Eric Schalnat, Group 42, Inc.
@@ -179,11 +179,11 @@ int main(int argc, const char **argv)
  *    components.
  *
  * You do not have to read directly from a file.  You can read from memory or,
- * on systems that support it, from a <stdio.h> FILE*.  This is controlled by
+ * on systems that support <stdio.h>, from a FILE object.  This is controlled
- * the particular png_image_read_from_ function you call at the start.
+ * by the particular png_image_begin_read_from_ function you call at the start.
- * Likewise, on write, you can write to a FILE* if your system supports it.
+ * Likewise, on write, you can write to a FILE object if your system supports
- * Check the macro PNG_STDIO_SUPPORTED to see if stdio support has been
+ * <stdio.h>.  The macro PNG_STDIO_SUPPORTED indicates if stdio is available
- * included in your libpng build.
+ * and accessible from your libpng build.
  *
  * If you read 16-bit (PNG_FORMAT_FLAG_LINEAR) data, you may need to write it
  * in the 8-bit format for display.  You do this by setting the convert_to_8bit

install-sh

@@ -1,7 +1,7 @@
 #!/bin/sh
 # install - install a program, script, or datafile
 
-scriptversion=2024-06-19.01; # UTC
+scriptversion=2025-06-18.21; # UTC
 
 # This originates from X11R5 (mit/util/scripts/install.sh), which was
 # later released in X11R6 (xc/config/util/install.sh) with the
@@ -533,9 +533,9 @@ do
 done
 
 # Local variables:
-# eval: (add-hook 'before-save-hook 'time-stamp)
+# eval: (add-hook 'before-save-hook 'time-stamp nil t)
 # time-stamp-start: "scriptversion="
-# time-stamp-format: "%:y-%02m-%02d.%02H"
+# time-stamp-format: "%Y-%02m-%02d.%02H"
 # time-stamp-time-zone: "UTC0"
 # time-stamp-end: "; # UTC"
 # End:

libpng-manual.txt

@@ -9,7 +9,7 @@ libpng-manual.txt - A description on how to use and modify libpng
 
  Based on:
 
- libpng version 1.6.36, December 2018, through 1.6.47 - February 2025
+ libpng version 1.6.36, December 2018, through 1.6.50 - July 2025
  Updated and distributed by Cosmin Truta
  Copyright (c) 2018-2025 Cosmin Truta
 
@@ -65,18 +65,22 @@ Libpng was written as a companion to the PNG specification, as a way
 of reducing the amount of time and effort it takes to support the PNG
 file format in application programs.
 
-The PNG specification (second edition), November 2003, is available as
+The PNG specification (Third Edition), June 2025, is available as
+a W3C Recommendation at
+<https://www.w3.org/TR/2025/REC-png-3-20250624/>.
+
+The PNG specification (Second Edition), November 2003, is available as
 a W3C Recommendation and as an ISO Standard (ISO/IEC 15948:2004 (E)) at
 <https://www.w3.org/TR/2003/REC-PNG-20031110/>.
 The W3C and ISO documents have identical technical content.
 
 The PNG-1.2 specification is available at
-<https://png-mng.sourceforge.io/pub/png/spec/1.2/>.
+<https://www.libpng.org/pub/png/spec/1.2/>.
-It is technically equivalent
+It is technically equivalent to the PNG specification (Second Edition)
-to the PNG specification (second edition) but has some additional material.
+but has some additional material.
 
 The PNG-1.0 specification is available as RFC 2083 at
-<https://png-mng.sourceforge.io/pub/png/spec/1.0/> and as a
+<https://www.libpng.org/pub/png/spec/1.0/> and as a
 W3C Recommendation at <https://www.w3.org/TR/REC-png-961001>.
 
 Some additional chunks are described in the special-purpose public chunks
@@ -4089,7 +4093,7 @@ READ APIs
      is filled in from the PNG header in the file.
 
    int png_image_begin_read_from_stdio (png_imagep image,
-     FILE* file)
+     FILE *file)
 
       The PNG header is read from the stdio FILE object.
 
@@ -4164,7 +4168,7 @@ be written:
       int convert_to_8_bit, const void *buffer,
       png_int_32 row_stride, const void *colormap)
 
-      Write the image to the given (FILE*).
+      Write the image to the given FILE object.
 
 With all write APIs if image is in one of the linear formats with
 (png_uint_16) data then setting convert_to_8_bit will cause the output to be

libpng.3

@@ -1,6 +1,6 @@
-.TH LIBPNG 3 "February 18, 2025"
+.TH LIBPNG 3 "July 1, 2025"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.6.47
+libpng \- Portable Network Graphics (PNG) Reference Library 1.6.50
 
 .SH SYNOPSIS
 \fB#include <png.h>\fP
@@ -223,7 +223,7 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.6.47
 
 \fBint png_image_begin_read_from_file (png_imagep \fP\fIimage\fP\fB, const char \fI*file_name\fP\fB);\fP
 
-\fBint png_image_begin_read_from_stdio (png_imagep \fP\fIimage\fP\fB, FILE* \fIfile\fP\fB);\fP
+\fBint png_image_begin_read_from_stdio (png_imagep \fP\fIimage\fP\fB, FILE *\fIfile\fP\fB);\fP
 
 \fBint, png_image_begin_read_from_memory (png_imagep \fP\fIimage\fP\fB, png_const_voidp \fP\fImemory\fP\fB, size_t \fIsize\fP\fB);\fP
 
@@ -528,7 +528,7 @@ libpng-manual.txt - A description on how to use and modify libpng
 
  Based on:
 
- libpng version 1.6.36, December 2018, through 1.6.47 - February 2025
+ libpng version 1.6.36, December 2018, through 1.6.50 - July 2025
  Updated and distributed by Cosmin Truta
  Copyright (c) 2018-2025 Cosmin Truta
 
@@ -584,18 +584,22 @@ Libpng was written as a companion to the PNG specification, as a way
 of reducing the amount of time and effort it takes to support the PNG
 file format in application programs.
 
-The PNG specification (second edition), November 2003, is available as
+The PNG specification (Third Edition), June 2025, is available as
+a W3C Recommendation at
+<https://www.w3.org/TR/2025/REC-png-3-20250624/>.
+
+The PNG specification (Second Edition), November 2003, is available as
 a W3C Recommendation and as an ISO Standard (ISO/IEC 15948:2004 (E)) at
 <https://www.w3.org/TR/2003/REC-PNG-20031110/>.
 The W3C and ISO documents have identical technical content.
 
 The PNG-1.2 specification is available at
-<https://png-mng.sourceforge.io/pub/png/spec/1.2/>.
+<https://www.libpng.org/pub/png/spec/1.2/>.
-It is technically equivalent
+It is technically equivalent to the PNG specification (Second Edition)
-to the PNG specification (second edition) but has some additional material.
+but has some additional material.
 
 The PNG-1.0 specification is available as RFC 2083 at
-<https://png-mng.sourceforge.io/pub/png/spec/1.0/> and as a
+<https://www.libpng.org/pub/png/spec/1.0/> and as a
 W3C Recommendation at <https://www.w3.org/TR/REC-png-961001>.
 
 Some additional chunks are described in the special-purpose public chunks
@@ -4608,7 +4612,7 @@ READ APIs
      is filled in from the PNG header in the file.
 
    int png_image_begin_read_from_stdio (png_imagep image,
-     FILE* file)
+     FILE *file)
 
       The PNG header is read from the stdio FILE object.
 
@@ -4683,7 +4687,7 @@ be written:
       int convert_to_8_bit, const void *buffer,
       png_int_32 row_stride, const void *colormap)
 
-      Write the image to the given (FILE*).
+      Write the image to the given FILE object.
 
 With all write APIs if image is in one of the linear formats with
 (png_uint_16) data then setting convert_to_8_bit will cause the output to be

libpngpf.3

@@ -1,24 +1,17 @@
-.TH LIBPNGPF 3 "February 18, 2025"
+.TH LIBPNGPF 3 "July 1, 2025"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.6.47
+libpng \- Portable Network Graphics (PNG) Reference Library 1.6.50
-(private functions)
 
 .SH SYNOPSIS
-\fB#include \fI"pngpriv.h"
+\fB#include "pngpriv.h"\fP
-
-\fBAs of libpng version \fP\fI1.5.1\fP\fB, this section is no longer
-\fP\fImaintained\fP\fB, now that the private function prototypes are hidden in
-\fP\fIpngpriv.h\fP\fB and not accessible to applications. Look in
-\fP\fIpngpriv.h\fP\fB for the prototypes and a short description of each
-function.
 
 .SH DESCRIPTION
-The functions previously listed here are used privately by libpng and are not
+As of libpng version 1.5.1, this manual is no longer maintained.  The private
-available for use by applications.  They are not "exported" to applications
+function prototypes, declared in private header files, should not be accessed
-using shared libraries.
+by applications.
 
 .SH "SEE ALSO"
-.BR "png"(5), " libpng"(3), " zlib"(3), " deflate"(5), " " and " zlib"(5)
+.BR "libpng"(3)
 
 .SH AUTHORS
 Cosmin Truta, Glenn Randers-Pehrson

mips/mips_init.c

@@ -48,7 +48,7 @@ static int png_have_msa(png_structp png_ptr);
 #include PNG_MIPS_MSA_FILE
 
 #else  /* PNG_MIPS_MSA_FILE */
-#  error "PNG_MIPS_MSA_FILE undefined: no support for run-time MIPS MSA checks"
+#  error PNG_MIPS_MSA_FILE undefined: no support for run-time MIPS MSA checks
 #endif /* PNG_MIPS_MSA_FILE */
 #endif /* PNG_MIPS_MSA_CHECK_SUPPORTED */
 
@@ -66,12 +66,12 @@ static int png_have_mmi();
 #include PNG_MIPS_MMI_FILE
 
 #else  /* PNG_MIPS_MMI_FILE */
-#  error "PNG_MIPS_MMI_FILE undefined: no support for run-time MIPS MMI checks"
+#  error PNG_MIPS_MMI_FILE undefined: no support for run-time MIPS MMI checks
 #endif /* PNG_MIPS_MMI_FILE */
 #endif /* PNG_MIPS_MMI_CHECK_SUPPORTED*/
 
 #ifndef PNG_ALIGNED_MEMORY_SUPPORTED
-#  error "ALIGNED_MEMORY is required; set: -DPNG_ALIGNED_MEMORY_SUPPORTED"
+#  error ALIGNED_MEMORY is required; please define PNG_ALIGNED_MEMORY_SUPPORTED
 #endif
 
 /* MIPS supports two optimizations: MMI and MSA. The appropriate

missing

@@ -1,11 +1,11 @@
 #! /bin/sh
 # Common wrapper for a few potentially missing GNU and other programs.
 
-scriptversion=2024-06-07.14; # UTC
+scriptversion=2025-06-18.21; # UTC
 
 # shellcheck disable=SC2006,SC2268 # we must support pre-POSIX shells
 
-# Copyright (C) 1996-2024 Free Software Foundation, Inc.
+# Copyright (C) 1996-2025 Free Software Foundation, Inc.
 # Originally written by Fran,cois Pinard <pinard@iro.umontreal.ca>, 1996.
 
 # This program is free software; you can redistribute it and/or modify
@@ -228,9 +228,9 @@ give_advice "$1" | sed -e '1s/^/WARNING: /' \
 exit $st
 
 # Local variables:
-# eval: (add-hook 'before-save-hook 'time-stamp)
+# eval: (add-hook 'before-save-hook 'time-stamp nil t)
 # time-stamp-start: "scriptversion="
-# time-stamp-format: "%:y-%02m-%02d.%02H"
+# time-stamp-format: "%Y-%02m-%02d.%02H"
 # time-stamp-time-zone: "UTC0"
 # time-stamp-end: "; # UTC"
 # End:

png.5

@@ -1,4 +1,4 @@
-.TH PNG 5 "February 18, 2025"
+.TH PNG 5 "July 1, 2025"
 .SH NAME
 png \- Portable Network Graphics (PNG) format
 
@@ -20,20 +20,25 @@ matching on heterogeneous platforms.
 .SH "SEE ALSO"
 .BR "libpng"(3), " zlib"(3), " deflate"(5), " " and " zlib"(5)
 .LP
-PNG Specification (Third Edition) Candidate Recommendation Draft, January 2025:
+PNG Specification (Third Edition), June 2025:
 .IP
 .br
-https://www.w3.org/TR/2025/CRD-png-3-20250121/
+https://www.w3.org/TR/2025/REC-png-3-20250624/
 .LP
 PNG Specification (Second Edition), November 2003:
 .IP
 .br
 https://www.w3.org/TR/2003/REC-PNG-20031110/
 .LP
-PNG 1.2 Specification, July 1999:
+PNG 1.2 Specification, August 1999:
 .IP
 .br
-https://png-mng.sourceforge.io/pub/png/spec/1.2/
+https://www.libpng.org/pub/png/spec/1.2/
+.LP
+PNG 1.1 Specification, December 1998:
+.IP
+.br
+https://www.libpng.org/pub/png/spec/1.1/
 .LP
 PNG 1.0 Specification, October 1996:
 .IP
@@ -50,15 +55,24 @@ https://www.w3.org/TR/REC-png-961001
 .SH AUTHORS
 This man page: Glenn Randers-Pehrson, Cosmin Truta
 .LP
+Portable Network Graphics (PNG) Specification (Third Edition).
+W3C Recommendation 24 June 2025:
+Chris Blume et al.
+.LP
 Portable Network Graphics (PNG) Specification (Second Edition)
 Information technology - Computer graphics and image processing -
 Portable Network Graphics (PNG): Functional specification.
-ISO/IEC 15948:2003 (E) (November 10, 2003): David Duce and others.
+ISO/IEC 15948:2003 (E), W3C Recommendation 10 November 2003:
+David Duce et al.
 .LP
-Portable Network Graphics (PNG) Specification Version 1.2 (July 8, 1999):
+Portable Network Graphics (PNG) Specification Version 1.2 (11 August 1999):
-Glenn Randers-Pehrson and others.
+Glenn Randers-Pehrson et al.
 .LP
-Portable Network Graphics (PNG) Specification Version 1.0 (October 1, 1996):
+Portable Network Graphics (PNG) Specification Version 1.1 (31 December 1998):
-Thomas Boutell and others.
+Glenn Randers-Pehrson et al.
+.LP
+Portable Network Graphics (PNG) Specification Version 1.0.
+IETF RFC 2083, W3C Recommendation 1 October 1996:
+Thomas Boutell et al.
 
 .\" end of man page

png.c

@@ -13,7 +13,7 @@
 #include "pngpriv.h"
 
 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef png_libpng_version_1_6_47 Your_png_h_is_not_version_1_6_47;
+typedef png_libpng_version_1_6_51_git Your_png_h_is_not_version_1_6_51_git;
 
 /* Sanity check the chunks definitions - PNG_KNOWN_CHUNKS from pngpriv.h and the
  * corresponding macro definitions.  This causes a compile time failure if
@@ -108,10 +108,16 @@ png_zalloc,(voidpf png_ptr, uInt items, uInt size),PNG_ALLOCATED)
    if (png_ptr == NULL)
       return NULL;
 
-   if (items >= (~(png_alloc_size_t)0)/size)
+   /* This check against overflow is vestigial, dating back from
+    * the old times when png_zalloc used to be an exported function.
+    * We're still keeping it here for now, as an extra-cautious
+    * prevention against programming errors inside zlib, although it
+    * should rather be a debug-time assertion instead.
+    */
+   if (size != 0 && items >= (~(png_alloc_size_t)0) / size)
    {
-      png_warning (png_voidcast(png_structrp, png_ptr),
+      png_warning(png_voidcast(png_structrp, png_ptr),
-          "Potential overflow in png_zalloc()");
+                  "Potential overflow in png_zalloc()");
       return NULL;
    }
 
@@ -700,7 +706,7 @@ png_get_io_ptr(png_const_structrp png_ptr)
  * function of your own because "FILE *" isn't necessarily available.
  */
 void PNGAPI
-png_init_io(png_structrp png_ptr, png_FILE_p fp)
+png_init_io(png_structrp png_ptr, FILE *fp)
 {
    png_debug(1, "in png_init_io");
 
@@ -815,7 +821,7 @@ png_get_copyright(png_const_structrp png_ptr)
    return PNG_STRING_COPYRIGHT
 #else
    return PNG_STRING_NEWLINE \
-      "libpng version 1.6.47" PNG_STRING_NEWLINE \
+      "libpng version 1.6.51.git" PNG_STRING_NEWLINE \
       "Copyright (c) 2018-2025 Cosmin Truta" PNG_STRING_NEWLINE \
       "Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson" \
       PNG_STRING_NEWLINE \
@@ -1491,7 +1497,7 @@ png_XYZ_from_xy(png_XYZ *XYZ, const png_xy *xy)
 }
 #endif /* COLORSPACE */
 
-#ifdef PNG_iCCP_SUPPORTED
+#ifdef PNG_READ_iCCP_SUPPORTED
 /* Error message generation */
 static char
 png_icc_tag_char(png_uint_32 byte)
@@ -1567,9 +1573,7 @@ png_icc_profile_error(png_const_structrp png_ptr, png_const_charp name,
 
    return 0;
 }
-#endif /* iCCP */
 
-#ifdef PNG_READ_iCCP_SUPPORTED
 /* Encoded value of D50 as an ICC XYZNumber.  From the ICC 2010 spec the value
  * is XYZ(0.9642,1.0,0.8249), which scales to:
  *
@@ -3969,7 +3973,7 @@ png_image_free_function(png_voidp argument)
 #  ifdef PNG_STDIO_SUPPORTED
       if (cp->owned_file != 0)
       {
-         FILE *fp = png_voidcast(FILE*, cp->png_ptr->io_ptr);
+         FILE *fp = png_voidcast(FILE *, cp->png_ptr->io_ptr);
          cp->owned_file = 0;
 
          /* Ignore errors here. */

png.h

@@ -1,6 +1,6 @@
 /* png.h - header file for PNG reference library
  *
- * libpng version 1.6.47
+ * libpng version 1.6.51.git
  *
  * Copyright (c) 2018-2025 Cosmin Truta
  * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
@@ -14,7 +14,7 @@
  *   libpng versions 0.89, June 1996, through 0.96, May 1997: Andreas Dilger
  *   libpng versions 0.97, January 1998, through 1.6.35, July 2018:
  *     Glenn Randers-Pehrson
- *   libpng versions 1.6.36, December 2018, through 1.6.47, February 2025:
+ *   libpng versions 1.6.36, December 2018, through 1.6.50, July 2025:
  *     Cosmin Truta
  *   See also "Contributing Authors", below.
  */
@@ -238,7 +238,7 @@
  *    ...
  *    1.5.30                  15    10530  15.so.15.30[.0]
  *    ...
- *    1.6.47                  16    10647  16.so.16.47[.0]
+ *    1.6.50                  16    10650  16.so.16.50[.0]
  *
  *    Henceforth the source version will match the shared-library major and
  *    minor numbers; the shared-library major version number will be used for
@@ -274,7 +274,7 @@
  */
 
 /* Version information for png.h - this should match the version in png.c */
-#define PNG_LIBPNG_VER_STRING "1.6.47"
+#define PNG_LIBPNG_VER_STRING "1.6.51.git"
 #define PNG_HEADER_VERSION_STRING " libpng version " PNG_LIBPNG_VER_STRING "\n"
 
 /* The versions of shared library builds should stay in sync, going forward */
@@ -285,12 +285,12 @@
 /* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
 #define PNG_LIBPNG_VER_MAJOR   1
 #define PNG_LIBPNG_VER_MINOR   6
-#define PNG_LIBPNG_VER_RELEASE 47
+#define PNG_LIBPNG_VER_RELEASE 51
 
 /* This should be zero for a public release, or non-zero for a
  * development version.
  */
-#define PNG_LIBPNG_VER_BUILD 0
+#define PNG_LIBPNG_VER_BUILD 1
 
 /* Release Status */
 #define PNG_LIBPNG_BUILD_ALPHA               1
@@ -307,7 +307,7 @@
 #define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
                                        PNG_LIBPNG_BUILD_PRIVATE */
 
-#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_STABLE
+#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_BETA
 
 /* Careful here.  At one time, Guy wanted to use 082, but that
  * would be octal.  We must not include leading zeros.
@@ -316,7 +316,7 @@
  * From version 1.0.1 it is:
  * XXYYZZ, where XX=major, YY=minor, ZZ=release
  */
-#define PNG_LIBPNG_VER 10647 /* 1.6.47 */
+#define PNG_LIBPNG_VER 10651 /* 1.6.51.git */
 
 /* Library configuration: these options cannot be changed after
  * the library has been built.
@@ -426,7 +426,7 @@ extern "C" {
 /* This triggers a compiler error in png.c, if png.c and png.h
  * do not agree upon the version number.
  */
-typedef char* png_libpng_version_1_6_47;
+typedef char* png_libpng_version_1_6_51_git;
 
 /* Basic control structions.  Read libpng-manual.txt or libpng.3 for more info.
  *
@@ -1570,7 +1570,7 @@ PNG_EXPORT(226, void, png_set_text_compression_method, (png_structrp png_ptr,
 
 #ifdef PNG_STDIO_SUPPORTED
 /* Initialize the input/output for the PNG file to the default functions. */
-PNG_EXPORT(74, void, png_init_io, (png_structrp png_ptr, png_FILE_p fp));
+PNG_EXPORT(74, void, png_init_io, (png_structrp png_ptr, FILE *fp));
 #endif
 
 /* Replace the (error and abort), and warning functions with user
@@ -3088,7 +3088,7 @@ PNG_EXPORT(234, int, png_image_begin_read_from_file, (png_imagep image,
     */
 
 PNG_EXPORT(235, int, png_image_begin_read_from_stdio, (png_imagep image,
-   FILE* file));
+   FILE *file));
    /* The PNG header is read from the stdio FILE object. */
 #endif /* STDIO */
 
@@ -3163,7 +3163,7 @@ PNG_EXPORT(239, int, png_image_write_to_file, (png_imagep image,
 PNG_EXPORT(240, int, png_image_write_to_stdio, (png_imagep image, FILE *file,
    int convert_to_8_bit, const void *buffer, png_int_32 row_stride,
    const void *colormap));
-   /* Write the image to the given (FILE*). */
+   /* Write the image to the given FILE object. */
 #endif /* SIMPLIFIED_WRITE_STDIO */
 
 /* With all write APIs if image is in one of the linear formats with 16-bit
@@ -3303,26 +3303,45 @@ PNG_EXPORT(245, int, png_image_write_to_memory, (png_imagep image, void *memory,
  *           selected at run time.
  */
 #ifdef PNG_SET_OPTION_SUPPORTED
+
+/* HARDWARE: ARM Neon SIMD instructions supported */
 #ifdef PNG_ARM_NEON_API_SUPPORTED
-#  define PNG_ARM_NEON   0 /* HARDWARE: ARM Neon SIMD instructions supported */
+#  define PNG_ARM_NEON 0
-#endif
-#define PNG_MAXIMUM_INFLATE_WINDOW 2 /* SOFTWARE: force maximum window */
-#define PNG_SKIP_sRGB_CHECK_PROFILE 4 /* SOFTWARE: Check ICC profile for sRGB */
-#ifdef PNG_MIPS_MSA_API_SUPPORTED
-#  define PNG_MIPS_MSA   6 /* HARDWARE: MIPS Msa SIMD instructions supported */
-#endif
-#ifdef PNG_DISABLE_ADLER32_CHECK_SUPPORTED
-#  define PNG_IGNORE_ADLER32 8 /* SOFTWARE: disable Adler32 check on IDAT */
-#endif
-#ifdef PNG_POWERPC_VSX_API_SUPPORTED
-#  define PNG_POWERPC_VSX   10 /* HARDWARE: PowerPC VSX SIMD instructions
-                                * supported */
-#endif
-#ifdef PNG_MIPS_MMI_API_SUPPORTED
-#  define PNG_MIPS_MMI   12 /* HARDWARE: MIPS MMI SIMD instructions supported */
 #endif
 
-#define PNG_OPTION_NEXT  14 /* Next option - numbers must be even */
+/* SOFTWARE: Force maximum window */
+#define PNG_MAXIMUM_INFLATE_WINDOW 2
+
+/* SOFTWARE: Check ICC profile for sRGB */
+#define PNG_SKIP_sRGB_CHECK_PROFILE 4
+
+/* HARDWARE: MIPS MSA SIMD instructions supported */
+#ifdef PNG_MIPS_MSA_API_SUPPORTED
+#  define PNG_MIPS_MSA 6
+#endif
+
+/* SOFTWARE: Disable Adler32 check on IDAT */
+#ifdef PNG_DISABLE_ADLER32_CHECK_SUPPORTED
+#  define PNG_IGNORE_ADLER32 8
+#endif
+
+/* HARDWARE: PowerPC VSX SIMD instructions supported */
+#ifdef PNG_POWERPC_VSX_API_SUPPORTED
+#  define PNG_POWERPC_VSX 10
+#endif
+
+/* HARDWARE: MIPS MMI SIMD instructions supported */
+#ifdef PNG_MIPS_MMI_API_SUPPORTED
+#  define PNG_MIPS_MMI 12
+#endif
+
+/* HARDWARE: RISC-V RVV SIMD instructions supported */
+#ifdef PNG_RISCV_RVV_API_SUPPORTED
+#  define PNG_RISCV_RVV 14
+#endif
+
+/* Next option - numbers must be even */
+#define PNG_OPTION_NEXT 16
 
 /* Return values: NOTE: there are four values and 'off' is *not* zero */
 #define PNG_OPTION_UNSET   0 /* Unset - defaults to off */

pngconf.h

@@ -1,6 +1,6 @@
 /* pngconf.h - machine-configurable file for libpng
  *
- * libpng version 1.6.47
+ * libpng version 1.6.51.git
  *
  * Copyright (c) 2018-2025 Cosmin Truta
  * Copyright (c) 1998-2002,2004,2006-2016,2018 Glenn Randers-Pehrson
@@ -219,25 +219,13 @@
   /* NOTE: PNGCBAPI always defaults to PNGCAPI. */
 
 #  if defined(PNGAPI) && !defined(PNG_USER_PRIVATEBUILD)
-#     error "PNG_USER_PRIVATEBUILD must be defined if PNGAPI is changed"
+#     error PNG_USER_PRIVATEBUILD must be defined if PNGAPI is changed
 #  endif
 
-#  if (defined(_MSC_VER) && _MSC_VER < 800) ||\
+#  define PNG_DLL_EXPORT __declspec(dllexport)
-      (defined(__BORLANDC__) && __BORLANDC__ < 0x500)
+#  ifndef PNG_DLL_IMPORT
-   /* older Borland and MSC
+#    define PNG_DLL_IMPORT __declspec(dllimport)
-    * compilers used '__export' and required this to be after
+#  endif
-    * the type.
-    */
-#    ifndef PNG_EXPORT_TYPE
-#      define PNG_EXPORT_TYPE(type) type PNG_IMPEXP
-#    endif
-#    define PNG_DLL_EXPORT __export
-#  else /* newer compiler */
-#    define PNG_DLL_EXPORT __declspec(dllexport)
-#    ifndef PNG_DLL_IMPORT
-#      define PNG_DLL_IMPORT __declspec(dllimport)
-#    endif
-#  endif /* compiler */
 
 #else /* !Windows */
 #  if (defined(__IBMC__) || defined(__IBMCPP__)) && defined(__OS2__)
@@ -479,7 +467,7 @@
 #if CHAR_BIT == 8 && UCHAR_MAX == 255
    typedef unsigned char png_byte;
 #else
-#  error "libpng requires 8-bit bytes"
+#  error libpng requires 8-bit bytes
 #endif
 
 #if INT_MIN == -32768 && INT_MAX == 32767
@@ -487,7 +475,7 @@
 #elif SHRT_MIN == -32768 && SHRT_MAX == 32767
    typedef short png_int_16;
 #else
-#  error "libpng requires a signed 16-bit type"
+#  error libpng requires a signed 16-bit integer type
 #endif
 
 #if UINT_MAX == 65535
@@ -495,7 +483,7 @@
 #elif USHRT_MAX == 65535
    typedef unsigned short png_uint_16;
 #else
-#  error "libpng requires an unsigned 16-bit type"
+#  error libpng requires an unsigned 16-bit integer type
 #endif
 
 #if INT_MIN < -2147483646 && INT_MAX > 2147483646
@@ -503,7 +491,7 @@
 #elif LONG_MIN < -2147483646 && LONG_MAX > 2147483646
    typedef long int png_int_32;
 #else
-#  error "libpng requires a signed 32-bit (or more) type"
+#  error libpng requires a signed 32-bit (or longer) integer type
 #endif
 
 #if UINT_MAX > 4294967294U
@@ -511,7 +499,7 @@
 #elif ULONG_MAX > 4294967294U
    typedef unsigned long int png_uint_32;
 #else
-#  error "libpng requires an unsigned 32-bit (or more) type"
+#  error libpng requires an unsigned 32-bit (or longer) integer type
 #endif
 
 /* Prior to 1.6.0, it was possible to disable the use of size_t and ptrdiff_t.
@@ -592,10 +580,6 @@ typedef const png_fixed_point * png_const_fixed_point_p;
 typedef size_t                * png_size_tp;
 typedef const size_t          * png_const_size_tp;
 
-#ifdef PNG_STDIO_SUPPORTED
-typedef FILE            * png_FILE_p;
-#endif
-
 #ifdef PNG_FLOATING_POINT_SUPPORTED
 typedef double       * png_doublep;
 typedef const double * png_const_doublep;
@@ -617,6 +601,15 @@ typedef double          * * png_doublepp;
 /* Pointers to pointers to pointers; i.e., pointer to array */
 typedef char            * * * png_charppp;
 
+#ifdef PNG_STDIO_SUPPORTED
+/* With PNG_STDIO_SUPPORTED it was possible to use I/O streams that were
+ * not necessarily stdio FILE streams, to allow building Windows applications
+ * before Win32 and Windows CE applications before WinCE 3.0, but that kind
+ * of support has long been discontinued.
+ */
+typedef FILE            * png_FILE_p; /* [Deprecated] */
+#endif
+
 #endif /* PNG_BUILDING_SYMBOL_TABLE */
 
 #endif /* PNGCONF_H */

pngdebug.h

@@ -1,6 +1,6 @@
-/* pngdebug.h - Debugging macros for libpng, also used in pngtest.c
+/* pngdebug.h - internal debugging macros for libpng
  *
- * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 2018-2025 Cosmin Truta
  * Copyright (c) 1998-2002,2004,2006-2013 Glenn Randers-Pehrson
  * Copyright (c) 1996-1997 Andreas Dilger
  * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
@@ -10,6 +10,10 @@
  * and license in png.h
  */
 
+#ifndef PNGPRIV_H
+#  error This file must not be included by applications; please include <png.h>
+#endif
+
 /* Define PNG_DEBUG at compile time for debugging information.  Higher
  * numbers for PNG_DEBUG mean more debugging information.  This has
  * only been added since version 0.95 so it is not implemented throughout

pngerror.c

@@ -1,6 +1,6 @@
 /* pngerror.c - stub functions for i/o and memory allocation
  *
- * Copyright (c) 2018-2024 Cosmin Truta
+ * Copyright (c) 2018-2025 Cosmin Truta
  * Copyright (c) 1998-2002,2004,2006-2017 Glenn Randers-Pehrson
  * Copyright (c) 1996-1997 Andreas Dilger
  * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.

pngget.c

@@ -1,6 +1,6 @@
 /* pngget.c - retrieval of values from info struct
  *
- * Copyright (c) 2018-2024 Cosmin Truta
+ * Copyright (c) 2018-2025 Cosmin Truta
  * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
  * Copyright (c) 1996-1997 Andreas Dilger
  * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.

pnginfo.h

@@ -1,6 +1,6 @@
-/* pnginfo.h - header file for PNG reference library
+/* pnginfo.h - internal structures for libpng
  *
- * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 2018-2025 Cosmin Truta
  * Copyright (c) 1998-2002,2004,2006-2013,2018 Glenn Randers-Pehrson
  * Copyright (c) 1996-1997 Andreas Dilger
  * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
@@ -10,43 +10,20 @@
  * and license in png.h
  */
 
- /* png_info is a structure that holds the information in a PNG file so
+#ifndef PNGPRIV_H
- * that the application can find out the characteristics of the image.
+#  error This file must not be included by applications; please include <png.h>
- * If you are reading the file, this structure will tell you what is
+#endif
- * in the PNG file.  If you are writing the file, fill in the information
+
- * you want to put into the PNG file, using png_set_*() functions, then
+/* INTERNAL, PRIVATE definition of a PNG.
- * call png_write_info().
  *
- * The names chosen should be very close to the PNG specification, so
+ * png_info is a modifiable description of a PNG datastream.  The fields inside
- * consult that document for information about the meaning of each field.
+ * this structure are accessed through png_get_<CHUNK>() functions and modified
+ * using png_set_<CHUNK>() functions.
  *
- * With libpng < 0.95, it was only possible to directly set and read the
+ * Some functions in libpng do directly access members of png_info.  However,
- * the values in the png_info_struct, which meant that the contents and
+ * this should be avoided.  png_struct objects contain members which hold
- * order of the values had to remain fixed.  With libpng 0.95 and later,
+ * caches, sometimes optimised, of the values from png_info objects, and
- * however, there are now functions that abstract the contents of
+ * png_info is not passed to the functions which read and write image data.
- * png_info_struct from the application, so this makes it easier to use
- * libpng with dynamic libraries, and even makes it possible to use
- * libraries that don't have all of the libpng ancillary chunk-handing
- * functionality.  In libpng-1.5.0 this was moved into a separate private
- * file that is not visible to applications.
- *
- * The following members may have allocated storage attached that should be
- * cleaned up before the structure is discarded: palette, trans, text,
- * pcal_purpose, pcal_units, pcal_params, hist, iccp_name, iccp_profile,
- * splt_palettes, scal_unit, row_pointers, and unknowns.   By default, these
- * are automatically freed when the info structure is deallocated, if they were
- * allocated internally by libpng.  This behavior can be changed by means
- * of the png_data_freer() function.
- *
- * More allocation details: all the chunk-reading functions that
- * change these members go through the corresponding png_set_*
- * functions.  A function to clear these members is available: see
- * png_free_data().  The png_set_* functions do not depend on being
- * able to point info structure members to any of the storage they are
- * passed (they make their own copies), EXCEPT that the png_set_text
- * functions use the same storage passed to them in the text_ptr or
- * itxt_ptr structure argument, and the png_set_rows and png_set_unknowns
- * functions do not make their own copies.
  */
 #ifndef PNGINFO_H
 #define PNGINFO_H

pngmem.c

@@ -1,6 +1,6 @@
 /* pngmem.c - stub functions for memory allocation
  *
- * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 2018-2025 Cosmin Truta
  * Copyright (c) 1998-2002,2004,2006-2014,2016 Glenn Randers-Pehrson
  * Copyright (c) 1996-1997 Andreas Dilger
  * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.

pngpread.c

@@ -1,6 +1,6 @@
 /* pngpread.c - read a png file in push mode
  *
- * Copyright (c) 2018-2024 Cosmin Truta
+ * Copyright (c) 2018-2025 Cosmin Truta
  * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
  * Copyright (c) 1996-1997 Andreas Dilger
  * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
@@ -229,6 +229,14 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
          png_benign_error(png_ptr, "Too many IDATs found");
    }
 
+   else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+   {
+      /* These flags must be set consistently for all non-IDAT chunks,
+       * including the unknown chunks.
+       */
+      png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT | PNG_AFTER_IDAT;
+   }
+
    if (chunk_name == png_IHDR)
    {
       if (png_ptr->push_length != 13)

pngpriv.h

@@ -1,6 +1,6 @@
 /* pngpriv.h - private declarations for use inside libpng
  *
- * Copyright (c) 2018-2024 Cosmin Truta
+ * Copyright (c) 2018-2025 Cosmin Truta
  * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
  * Copyright (c) 1996-1997 Andreas Dilger
  * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
@@ -19,8 +19,20 @@
  * they should be well aware of the issues that may arise from doing so.
  */
 
+
+/* pngpriv.h must be included first in each translation unit inside libpng.
+ * On the other hand, it must not be included at all, directly or indirectly,
+ * by any application code that uses the libpng API.
+ */
 #ifndef PNGPRIV_H
-#define PNGPRIV_H
+#  define PNGPRIV_H
+#else
+#  error Duplicate inclusion of pngpriv.h; please check the libpng source files
+#endif
+
+#if defined(PNG_H) || defined(PNGCONF_H) || defined(PNGLCONF_H)
+#  error This file must not be included by applications; please include <png.h>
+#endif
 
 /* Feature Test Macros.  The following are defined here to ensure that correctly
  * implemented libraries reveal the APIs libpng needs to build and hide those
@@ -57,7 +69,6 @@
  */
 #if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
 #  include <config.h>
-
    /* Pick up the definition of 'restrict' from config.h if it was read: */
 #  define PNG_RESTRICT restrict
 #endif
@@ -67,9 +78,7 @@
  * are not internal definitions may be required.  This is handled below just
  * before png.h is included, but load the configuration now if it is available.
  */
-#ifndef PNGLCONF_H
+#include "pnglibconf.h"
-#  include "pnglibconf.h"
-#endif
 
 /* Local renames may change non-exported API functions from png.h */
 #if defined(PNG_PREFIX) && !defined(PNGPREFIX_H)
@@ -134,6 +143,20 @@
 #  endif
 #endif
 
+#ifndef PNG_RISCV_RVV_OPT
+   /* RISCV_RVV optimizations are being controlled by the compiler settings,
+    * typically the target compiler will define __riscv but the rvv extension
+    * availability has to be explicitly stated. This is why if no
+    * PNG_RISCV_RVV_OPT was defined then a runtime check will be executed.
+    *
+    * To enable RISCV_RVV optimizations unconditionally, and compile the
+    * associated code, pass --enable-riscv-rvv=yes or --enable-riscv-rvv=on
+    * to configure or put -DPNG_RISCV_RVV_OPT=2 in CPPFLAGS.
+    */
+
+#  define PNG_RISCV_RVV_OPT 0
+#endif
+
 #if PNG_ARM_NEON_OPT > 0
    /* NEON optimizations are to be at least considered by libpng, so enable the
     * callbacks to do this.
@@ -279,6 +302,16 @@
 #   define PNG_LOONGARCH_LSX_IMPLEMENTATION 0
 #endif
 
+#if PNG_RISCV_RVV_OPT > 0
+#  define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_rvv
+#  ifndef PNG_RISCV_RVV_IMPLEMENTATION
+      /* Use the intrinsics code by default. */
+#     define PNG_RISCV_RVV_IMPLEMENTATION 1
+#  endif
+#else
+#  define PNG_RISCV_RVV_IMPLEMENTATION 0
+#endif
+
 /* Is this a build of a DLL where compilation of the object modules requires
  * different preprocessor settings to those required for a simple library?  If
  * so PNG_BUILD_DLL must be set.
@@ -991,17 +1024,15 @@
  * must match that used in the build, or we must be using pnglibconf.h.prebuilt:
  */
 #if PNG_ZLIB_VERNUM != 0 && PNG_ZLIB_VERNUM != ZLIB_VERNUM
-#  error ZLIB_VERNUM != PNG_ZLIB_VERNUM \
+#  error The include path of <zlib.h> is incorrect
-      "-I (include path) error: see the notes in pngpriv.h"
+   /* When pnglibconf.h was built, the copy of zlib.h that it used was not the
-   /* This means that when pnglibconf.h was built the copy of zlib.h that it
+    * same as the one being used here.  Considering how libpng makes decisions
-    * used is not the same as the one being used here.  Because the build of
+    * to use the zlib API based on the zlib version number, the -I options must
-    * libpng makes decisions to use inflateInit2 and inflateReset2 based on the
+    * match.
-    * zlib version number and because this affects handling of certain broken
-    * PNG files the -I directives must match.
     *
-    * The most likely explanation is that you passed a -I in CFLAGS. This will
+    * A possible cause of this mismatch is that you passed an -I option in
-    * not work; all the preprocessor directives and in particular all the -I
+    * CFLAGS, which is unlikely to work.  All the preprocessor options, and all
-    * directives must be in CPPFLAGS.
+    * the -I options in particular, should be in CPPFLAGS.
     */
 #endif
 
@@ -1515,6 +1546,23 @@ PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_lsx,(png_row_infop
     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
 #endif
 
+#if PNG_RISCV_RVV_OPT > 0
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_up_rvv,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_rvv,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_rvv,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_rvv,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_rvv,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_rvv,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_rvv,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+#endif
+
 /* Choose the best filter to use and filter the row data */
 PNG_INTERNAL_FUNCTION(void,png_write_find_filter,(png_structrp png_ptr,
     png_row_infop row_info),PNG_EMPTY);
@@ -2127,6 +2175,11 @@ PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_lsx,
     (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
 #endif
 
+#  if PNG_RISCV_RVV_OPT > 0
+PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_rvv,
+   (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
+#endif
+
 PNG_INTERNAL_FUNCTION(png_uint_32, png_check_keyword, (png_structrp png_ptr,
    png_const_charp key, png_bytep new_key), PNG_EMPTY);
 
@@ -2162,4 +2215,3 @@ PNG_INTERNAL_FUNCTION(int,
 #endif
 
 #endif /* PNG_VERSION_INFO_ONLY */
-#endif /* PNGPRIV_H */

pngread.c

@@ -702,7 +702,12 @@ png_read_end(png_structrp png_ptr, png_inforp info_ptr)
       png_uint_32 chunk_name = png_ptr->chunk_name;
 
       if (chunk_name != png_IDAT)
-         png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
+      {
+         /* These flags must be set consistently for all non-IDAT chunks,
+          * including the unknown chunks.
+          */
+         png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT | PNG_AFTER_IDAT;
+      }
 
       if (chunk_name == png_IEND)
          png_handle_chunk(png_ptr, info_ptr, length);
@@ -809,7 +814,8 @@ png_read_destroy(png_structrp png_ptr)
 #endif
 
 #if defined(PNG_READ_EXPAND_SUPPORTED) && \
-    defined(PNG_ARM_NEON_IMPLEMENTATION)
+    (defined(PNG_ARM_NEON_IMPLEMENTATION) || \
+     defined(PNG_RISCV_RVV_IMPLEMENTATION))
    png_free(png_ptr, png_ptr->riffled_palette);
    png_ptr->riffled_palette = NULL;
 #endif
@@ -1328,7 +1334,7 @@ png_image_read_header(png_voidp argument)
 
 #ifdef PNG_STDIO_SUPPORTED
 int PNGAPI
-png_image_begin_read_from_stdio(png_imagep image, FILE* file)
+png_image_begin_read_from_stdio(png_imagep image, FILE *file)
 {
    if (image != NULL && image->version == PNG_IMAGE_VERSION)
    {

pngrio.c

@@ -1,6 +1,6 @@
 /* pngrio.c - functions for data input
  *
- * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 2018-2025 Cosmin Truta
  * Copyright (c) 1998-2002,2004,2006-2016,2018 Glenn Randers-Pehrson
  * Copyright (c) 1996-1997 Andreas Dilger
  * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
@@ -56,7 +56,7 @@ png_default_read_data(png_structp png_ptr, png_bytep data, size_t length)
    /* fread() returns 0 on error, so it is OK to store this in a size_t
     * instead of an int, which is what fread() actually returns.
     */
-   check = fread(data, 1, length, png_voidcast(png_FILE_p, png_ptr->io_ptr));
+   check = fread(data, 1, length, png_voidcast(FILE *, png_ptr->io_ptr));
 
    if (check != length)
       png_error(png_ptr, "Read Error");

pngrtran.c

@@ -1,6 +1,6 @@
 /* pngrtran.c - transforms the data in a row for PNG readers
  *
- * Copyright (c) 2018-2024 Cosmin Truta
+ * Copyright (c) 2018-2025 Cosmin Truta
  * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
  * Copyright (c) 1996-1997 Andreas Dilger
  * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
@@ -28,6 +28,12 @@
 #  endif
 #endif
 
+#ifdef PNG_RISCV_RVV_IMPLEMENTATION
+#  if PNG_RISCV_RVV_IMPLEMENTATION == 1
+#    define PNG_RISCV_RVV_INTRINSICS_AVAILABLE
+#  endif
+#endif
+
 #ifdef PNG_READ_SUPPORTED
 
 /* Set the action on getting a CRC error for an ancillary or critical chunk. */

pngrutil.c

@@ -1,6 +1,6 @@
 /* pngrutil.c - utilities to read a PNG file
  *
- * Copyright (c) 2018-2024 Cosmin Truta
+ * Copyright (c) 2018-2025 Cosmin Truta
  * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
  * Copyright (c) 1996-1997 Andreas Dilger
  * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
@@ -2412,10 +2412,6 @@ png_handle_tEXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
    }
 #endif
 
-   /* TODO: this doesn't work and shouldn't be necessary. */
-   if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
-      png_ptr->mode |= PNG_AFTER_IDAT;
-
    buffer = png_read_buffer(png_ptr, length+1);
 
    if (buffer == NULL)
@@ -2486,10 +2482,6 @@ png_handle_zTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
    }
 #endif
 
-   /* TODO: should not be necessary. */
-   if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
-      png_ptr->mode |= PNG_AFTER_IDAT;
-
    /* Note, "length" is sufficient here; we won't be adding
     * a null terminator later.  The limit check in png_handle_chunk should be
     * sufficient.
@@ -2606,10 +2598,6 @@ png_handle_iTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
    }
 #endif
 
-   /* TODO: should not be necessary. */
-   if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
-      png_ptr->mode |= PNG_AFTER_IDAT;
-
    buffer = png_read_buffer(png_ptr, length+1);
 
    if (buffer == NULL)

pngset.c

@@ -300,17 +300,14 @@ png_set_mDCV(png_const_structrp png_ptr, png_inforp info_ptr,
     double maxDL, double minDL)
 {
    png_set_mDCV_fixed(png_ptr, info_ptr,
-      /* The ITU approach is to scale by 50,000, not 100,000 so just divide
+      png_fixed(png_ptr, white_x, "png_set_mDCV(white(x))"),
-       * the input values by 2 and use png_fixed:
+      png_fixed(png_ptr, white_y, "png_set_mDCV(white(y))"),
-       */
+      png_fixed(png_ptr, red_x, "png_set_mDCV(red(x))"),
-      png_fixed(png_ptr, white_x / 2, "png_set_mDCV(white(x))"),
+      png_fixed(png_ptr, red_y, "png_set_mDCV(red(y))"),
-      png_fixed(png_ptr, white_y / 2, "png_set_mDCV(white(y))"),
+      png_fixed(png_ptr, green_x, "png_set_mDCV(green(x))"),
-      png_fixed(png_ptr, red_x / 2, "png_set_mDCV(red(x))"),
+      png_fixed(png_ptr, green_y, "png_set_mDCV(green(y))"),
-      png_fixed(png_ptr, red_y / 2, "png_set_mDCV(red(y))"),
+      png_fixed(png_ptr, blue_x, "png_set_mDCV(blue(x))"),
-      png_fixed(png_ptr, green_x / 2, "png_set_mDCV(green(x))"),
+      png_fixed(png_ptr, blue_y, "png_set_mDCV(blue(y))"),
-      png_fixed(png_ptr, green_y / 2, "png_set_mDCV(green(y))"),
-      png_fixed(png_ptr, blue_x / 2, "png_set_mDCV(blue(x))"),
-      png_fixed(png_ptr, blue_y / 2, "png_set_mDCV(blue(y))"),
       png_fixed_ITU(png_ptr, maxDL, "png_set_mDCV(maxDL)"),
       png_fixed_ITU(png_ptr, minDL, "png_set_mDCV(minDL)"));
 }

pngstruct.h

@@ -1,6 +1,6 @@
-/* pngstruct.h - header file for PNG reference library
+/* pngstruct.h - internal structures for libpng
  *
- * Copyright (c) 2018-2022 Cosmin Truta
+ * Copyright (c) 2018-2025 Cosmin Truta
  * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
  * Copyright (c) 1996-1997 Andreas Dilger
  * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
@@ -10,11 +10,9 @@
  * and license in png.h
  */
 
-/* The structure that holds the information to read and write PNG files.
+#ifndef PNGPRIV_H
- * The only people who need to care about what is inside of this are the
+#  error This file must not be included by applications; please include <png.h>
- * people who will be modifying the library for their own special needs.
+#endif
- * It should NOT be accessed directly by an application.
- */
 
 #ifndef PNGSTRUCT_H
 #define PNGSTRUCT_H
@@ -377,7 +375,8 @@ struct png_struct_def
 
 /* New member added in libpng-1.6.36 */
 #if defined(PNG_READ_EXPAND_SUPPORTED) && \
-    defined(PNG_ARM_NEON_IMPLEMENTATION)
+    (defined(PNG_ARM_NEON_IMPLEMENTATION) || \
+     defined(PNG_RISCV_RVV_IMPLEMENTATION))
    png_bytep riffled_palette; /* buffer for accelerated palette expansion */
 #endif
 

pngtest.c

@@ -50,7 +50,7 @@
 #define STDERR stdout
 
 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef png_libpng_version_1_6_47 Your_png_h_is_not_version_1_6_47;
+typedef png_libpng_version_1_6_51_git Your_png_h_is_not_version_1_6_51_git;
 
 /* Ensure that all version numbers in png.h are consistent with one another. */
 #if (PNG_LIBPNG_VER != PNG_LIBPNG_VER_MAJOR * 10000 + \
@@ -60,7 +60,7 @@ typedef png_libpng_version_1_6_47 Your_png_h_is_not_version_1_6_47;
                                  PNG_LIBPNG_VER_MINOR) || \
     (PNG_LIBPNG_VER_SHAREDLIB != PNG_LIBPNG_VER_SONUM) || \
     (PNG_LIBPNG_VER_SHAREDLIB != PNG_LIBPNG_VER_DLLNUM)
-#  error "Inconsistent version numbers in png.h"
+#  error Inconsistent version numbers in "png.h"
 #endif
 
 /* In version 1.6.1, we added support for the configure test harness, which
@@ -103,10 +103,6 @@ typedef png_libpng_version_1_6_47 Your_png_h_is_not_version_1_6_47;
 #  define PNG_ZBUF_SIZE 8192
 #endif
 
-#ifndef PNG_STDIO_SUPPORTED
-typedef FILE * png_FILE_p;
-#endif
-
 #ifndef PNG_DEBUG
 #  define PNG_DEBUG 0
 #endif
@@ -120,7 +116,7 @@ typedef FILE * png_FILE_p;
 #  define pngtest_debug1(m, p1)     ((void)0)
 #  define pngtest_debug2(m, p1, p2) ((void)0)
 #else /* PNG_DEBUG < 0 */
-#  error "Bad PNG_DEBUG value"
+#  error Bad PNG_DEBUG value
 #endif
 
 /* Turn on CPU timing
@@ -403,7 +399,7 @@ pngtest_read_data(png_structp png_ptr, png_bytep data, size_t length)
     */
    io_ptr = png_get_io_ptr(png_ptr);
    if (io_ptr != NULL)
-      check = fread(data, 1, length, (png_FILE_p)io_ptr);
+      check = fread(data, 1, length, (FILE *)io_ptr);
 
    if (check != length)
       png_error(png_ptr, "Read Error");
@@ -437,7 +433,7 @@ pngtest_write_data(png_structp png_ptr, png_bytep data, size_t length)
    if (png_ptr == NULL)
       png_error(png_ptr, "pngtest_write_data: bad png_ptr");
 
-   check = fwrite(data, 1, length, (png_FILE_p)png_get_io_ptr(png_ptr));
+   check = fwrite(data, 1, length, (FILE *)png_get_io_ptr(png_ptr));
 
    if (check != length)
       png_error(png_ptr, "Write Error");
@@ -858,8 +854,8 @@ pngtest_check_text_support(png_structp png_ptr, png_textp text_ptr,
 static int
 test_one_file(const char *inname, const char *outname)
 {
-   static png_FILE_p fpin;
+   static FILE *fpin;
-   static png_FILE_p fpout;  /* "static" prevents setjmp corruption */
+   static FILE *fpout;  /* "static" prevents setjmp corruption */
    pngtest_error_parameters error_parameters;
    png_structp read_ptr;
    png_infop read_info_ptr, end_info_ptr;

pngwio.c

@@ -1,6 +1,6 @@
 /* pngwio.c - functions for data output
  *
- * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 2018-2025 Cosmin Truta
  * Copyright (c) 1998-2002,2004,2006-2014,2016,2018 Glenn Randers-Pehrson
  * Copyright (c) 1996-1997 Andreas Dilger
  * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
@@ -54,7 +54,7 @@ png_default_write_data(png_structp png_ptr, png_bytep data, size_t length)
    if (png_ptr == NULL)
       return;
 
-   check = fwrite(data, 1, length, (png_FILE_p)(png_ptr->io_ptr));
+   check = fwrite(data, 1, length, (FILE *)png_ptr->io_ptr);
 
    if (check != length)
       png_error(png_ptr, "Write Error");
@@ -77,12 +77,12 @@ png_flush(png_structrp png_ptr)
 void PNGCBAPI
 png_default_flush(png_structp png_ptr)
 {
-   png_FILE_p io_ptr;
+   FILE *io_ptr;
 
    if (png_ptr == NULL)
       return;
 
-   io_ptr = png_voidcast(png_FILE_p, (png_ptr->io_ptr));
+   io_ptr = png_voidcast(FILE *, png_ptr->io_ptr);
    fflush(io_ptr);
 }
 #  endif

pngwrite.c

@@ -2333,7 +2333,7 @@ int PNGAPI
 png_image_write_to_stdio(png_imagep image, FILE *file, int convert_to_8bit,
     const void *buffer, png_int_32 row_stride, const void *colormap)
 {
-   /* Write the image to the given (FILE*). */
+   /* Write the image to the given FILE object. */
    if (image != NULL && image->version == PNG_IMAGE_VERSION)
    {
       if (file != NULL && buffer != NULL)

pngwutil.c

@@ -1,6 +1,6 @@
 /* pngwutil.c - utilities to write a PNG file
  *
- * Copyright (c) 2018-2024 Cosmin Truta
+ * Copyright (c) 2018-2025 Cosmin Truta
  * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
  * Copyright (c) 1996-1997 Andreas Dilger
  * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.

powerpc/filter_vsx_intrinsics.c

@@ -23,7 +23,7 @@
 #if PNG_POWERPC_VSX_OPT > 0
 
 #ifndef __VSX__
-#  error "This code requires VSX support (POWER7 and later). Please provide -mvsx compiler flag."
+#  error This code requires VSX support (POWER7 and later); please compile with -mvsx
 #endif
 
 #define vec_ld_unaligned(vec,data) vec = vec_vsx_ld(0,data)

powerpc/powerpc_init.c

@@ -46,7 +46,7 @@ static int png_have_vsx(png_structp png_ptr);
 #include PNG_POWERPC_VSX_FILE
 
 #else  /* PNG_POWERPC_VSX_FILE */
-#  error "PNG_POWERPC_VSX_FILE undefined: no support for run-time POWERPC VSX checks"
+#  error PNG_POWERPC_VSX_FILE undefined: no support for run-time POWERPC VSX checks
 #endif /* PNG_POWERPC_VSX_FILE */
 #endif /* PNG_POWERPC_VSX_CHECK_SUPPORTED */
 

projects/visualc71/libpng.vcproj

@@ -66,7 +66,7 @@
 				Name="VCCLCompilerTool"
 				Optimization="0"
 				AdditionalIncludeDirectories="..\..;..\..\..\zlib"
-				PreprocessorDefinitions="WIN32;_DEBUG;DEBUG;PNG_DEBUG=1;PNG_BUILD_DLL;ZLIB_DLL;_CRT_SECURE_NO_WARNINGS"
+				PreprocessorDefinitions="WIN32;_DEBUG;DEBUG;PNG_BUILD_DLL;ZLIB_DLL;_CRT_SECURE_NO_WARNINGS"
 				BasicRuntimeChecks="3"
 				RuntimeLibrary="3"
 				UsePrecompiledHeader="3"
@@ -91,7 +91,7 @@
 				Name="VCPreLinkEventTool"/>
 			<Tool
 				Name="VCResourceCompilerTool"
-				PreprocessorDefinitions="_DEBUG,PNG_DEBUG=1"
+				PreprocessorDefinitions="_DEBUG"
 				Culture="1033"
 				AdditionalIncludeDirectories="..\..;..\..\..\zlib;$(IntDir)"/>
 			<Tool
@@ -205,7 +205,7 @@
 				Name="VCCLCompilerTool"
 				Optimization="0"
 				AdditionalIncludeDirectories="..\..;..\..\..\zlib"
-				PreprocessorDefinitions="WIN32;_DEBUG;DEBUG;PNG_DEBUG=1;_CRT_SECURE_NO_WARNINGS"
+				PreprocessorDefinitions="WIN32;_DEBUG;DEBUG;_CRT_SECURE_NO_WARNINGS"
 				BasicRuntimeChecks="3"
 				RuntimeLibrary="1"
 				UsePrecompiledHeader="3"

riscv/.editorconfig

@@ -0,0 +1,8 @@
+# https://editorconfig.org
+
+root = false
+
+# FIXME
+[*.[ch]]
+max_doc_length = unset
+max_line_length = unset

riscv/filter_rvv_intrinsics.c

@@ -0,0 +1,350 @@
+/* filter_rvv_intrinsics.c - RISC-V Vector optimized filter functions
+ *
+ * Copyright (c) 2023 Google LLC
+ * Written by Manfred SCHLAEGL, 2022
+ *            Dragoș Tiselice <dtiselice@google.com>, May 2023.
+ *            Filip Wasil     <f.wasil@samsung.com>, March 2025.
+ *
+ * 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"
+
+#ifdef PNG_READ_SUPPORTED
+
+#if PNG_RISCV_RVV_IMPLEMENTATION == 1 /* intrinsics code from pngpriv.h */
+
+#include <riscv_vector.h>
+
+void
+png_read_filter_row_up_rvv(png_row_infop row_info, png_bytep row,
+    png_const_bytep prev_row)
+{
+   size_t len = row_info->rowbytes;
+
+   for (size_t vl; len > 0; len -= vl, row += vl, prev_row += vl)
+   {
+      vl = __riscv_vsetvl_e8m8(len);
+
+      vuint8m8_t prev_vals = __riscv_vle8_v_u8m8(prev_row, vl);
+      vuint8m8_t row_vals = __riscv_vle8_v_u8m8(row, vl);
+
+      row_vals = __riscv_vadd_vv_u8m8(row_vals, prev_vals, vl);
+
+      __riscv_vse8_v_u8m8(row, row_vals, vl);
+   }
+}
+
+static inline void
+png_read_filter_row_sub_rvv(size_t len, size_t bpp, unsigned char* row)
+{
+   png_bytep rp_end = row + len;
+
+   /*
+    * row:      | a | x |
+    *
+    * a = a + x
+    *
+    * a .. [v0](e8)
+    * x .. [v8](e8)
+    */
+
+   size_t vl = __riscv_vsetvl_e8m1(bpp);
+
+   /* a = *row */
+   vuint8m1_t a = __riscv_vle8_v_u8m1(row, vl);
+   row += bpp;
+
+   while (row < rp_end)
+   {
+      /* x = *row */
+      vuint8m1_t x = __riscv_vle8_v_u8m1(row, vl);
+
+      /* a = a + x */
+      a = __riscv_vadd_vv_u8m1(a, x, vl);
+
+      /* *row = a */
+      __riscv_vse8_v_u8m1(row, a, vl);
+      row += bpp;
+   }
+}
+
+void
+png_read_filter_row_sub3_rvv(png_row_infop row_info, png_bytep row,
+    png_const_bytep prev_row)
+{
+   size_t len = row_info->rowbytes;
+
+   png_read_filter_row_sub_rvv(len, 3, row);
+
+   PNG_UNUSED(prev_row)
+}
+
+void
+png_read_filter_row_sub4_rvv(png_row_infop row_info, png_bytep row,
+    png_const_bytep prev_row)
+{
+   size_t len = row_info->rowbytes;
+
+   png_read_filter_row_sub_rvv(len, 4, row);
+
+   PNG_UNUSED(prev_row)
+}
+
+static inline void
+png_read_filter_row_avg_rvv(size_t len, size_t bpp, unsigned char* row,
+    const unsigned char* prev_row)
+{
+   png_bytep rp_end = row + len;
+
+   /*
+    * row:      | a | x |
+    * prev_row: |   | b |
+    *
+    * a ..   [v2](e8)
+    * b ..   [v4](e8)
+    * x ..   [v8](e8)
+    * tmp .. [v12-v13](e16)
+    */
+
+   /* first pixel */
+
+   size_t vl = __riscv_vsetvl_e8m1(bpp);
+
+   /* b = *prev_row */
+   vuint8m1_t b = __riscv_vle8_v_u8m1(prev_row, vl);
+   prev_row += bpp;
+
+   /* x = *row */
+   vuint8m1_t x = __riscv_vle8_v_u8m1(row, vl);
+
+   /* b = b / 2 */
+   b = __riscv_vsrl_vx_u8m1(b, 1, vl);
+
+   /* a = x + b */
+   vuint8m1_t a = __riscv_vadd_vv_u8m1(b, x, vl);
+
+   /* *row = a */
+   __riscv_vse8_v_u8m1(row, a, vl);
+   row += bpp;
+
+   /* remaining pixels */
+   while (row < rp_end)
+   {
+      /* b = *prev_row */
+      b = __riscv_vle8_v_u8m1(prev_row, vl);
+      prev_row += bpp;
+
+      /* x = *row */
+      x = __riscv_vle8_v_u8m1(row, vl);
+
+      /* tmp = a + b */
+      vuint16m2_t tmp = __riscv_vwaddu_vv_u16m2(a, b, vl);
+
+      /* a = tmp/2 */
+      a = __riscv_vnsrl_wx_u8m1(tmp, 1, vl);
+
+      /* a += x */
+      a = __riscv_vadd_vv_u8m1(a, x, vl);
+
+      /* *row = a */
+      __riscv_vse8_v_u8m1(row, a, vl);
+      row += bpp;
+   }
+}
+
+void
+png_read_filter_row_avg3_rvv(png_row_infop row_info, png_bytep row,
+    png_const_bytep prev_row)
+{
+   size_t len = row_info->rowbytes;
+
+   png_read_filter_row_avg_rvv(len, 3, row, prev_row);
+
+   PNG_UNUSED(prev_row)
+}
+
+void
+png_read_filter_row_avg4_rvv(png_row_infop row_info, png_bytep row,
+    png_const_bytep prev_row)
+{
+   size_t len = row_info->rowbytes;
+
+   png_read_filter_row_avg_rvv(len, 4, row, prev_row);
+
+   PNG_UNUSED(prev_row)
+}
+
+#define MIN_CHUNK_LEN 256
+#define MAX_CHUNK_LEN 2048
+
+static inline vuint8m1_t
+prefix_sum(vuint8m1_t chunk, unsigned char* carry, size_t vl,
+    size_t max_chunk_len)
+{
+   size_t r;
+
+   for (r = 1; r < MIN_CHUNK_LEN; r <<= 1)
+   {
+      vbool8_t shift_mask = __riscv_vmsgeu_vx_u8m1_b8(__riscv_vid_v_u8m1(vl), r, vl);
+      chunk = __riscv_vadd_vv_u8m1_mu(shift_mask, chunk, chunk, __riscv_vslideup_vx_u8m1(__riscv_vundefined_u8m1(), chunk, r, vl), vl);
+   }
+
+   for (r = MIN_CHUNK_LEN; r < MAX_CHUNK_LEN && r < max_chunk_len; r <<= 1)
+   {
+      vbool8_t shift_mask = __riscv_vmsgeu_vx_u8m1_b8(__riscv_vid_v_u8m1(vl), r, vl);
+      chunk = __riscv_vadd_vv_u8m1_mu(shift_mask, chunk, chunk, __riscv_vslideup_vx_u8m1(__riscv_vundefined_u8m1(), chunk, r, vl), vl);
+   }
+
+   chunk = __riscv_vadd_vx_u8m1(chunk, *carry, vl);
+   *carry = __riscv_vmv_x_s_u8m1_u8(__riscv_vslidedown_vx_u8m1(chunk, vl - 1, vl));
+
+   return chunk;
+}
+
+static inline vint16m1_t
+abs_diff(vuint16m1_t a, vuint16m1_t b, size_t vl)
+{
+   vint16m1_t diff = __riscv_vreinterpret_v_u16m1_i16m1(__riscv_vsub_vv_u16m1(a, b, vl));
+   vbool16_t mask = __riscv_vmslt_vx_i16m1_b16(diff, 0, vl);
+   return __riscv_vrsub_vx_i16m1_m(mask, diff, 0, vl);
+}
+
+static inline vint16m1_t
+abs_sum(vint16m1_t a, vint16m1_t b, size_t vl)
+{
+   return __riscv_vadd_vv_i16m1(a, b, vl);
+}
+
+static inline void
+png_read_filter_row_paeth_rvv(size_t len, size_t bpp, unsigned char* row,
+    const unsigned char* prev)
+{
+   png_bytep rp_end = row + len;
+
+   /*
+    * row:  | a | x |
+    * prev: | c | b |
+    *
+    * a .. [v2](e8)
+    * b .. [v4](e8)
+    * c .. [v6](e8)
+    * x .. [v8](e8)
+    * p .. [v12-v13](e16)
+    * pa, pb, pc .. [v16-v17, v20-v21, v24-v25](e16)
+    */
+
+   /* first pixel */
+
+   size_t vl = __riscv_vsetvl_e8m1(bpp);
+
+   /* a = *row */
+   vuint8m1_t a = __riscv_vle8_v_u8m1(row, vl);
+
+   /* c = *prev */
+   vuint8m1_t c = __riscv_vle8_v_u8m1(prev, vl);
+
+   /* a += c */
+   a = __riscv_vadd_vv_u8m1(a, c, vl);
+
+   /* *row = a */
+   __riscv_vse8_v_u8m1(row, a, vl);
+   row += bpp;
+   prev += bpp;
+
+   /* remaining pixels */
+
+   while (row < rp_end)
+   {
+      /* b = *prev */
+      vuint8m1_t b = __riscv_vle8_v_u8m1(prev, vl);
+      prev += bpp;
+
+      /* x = *row */
+      vuint8m1_t x = __riscv_vle8_v_u8m1(row, vl);
+
+      /* Calculate p = b - c and pc = a - c using widening subtraction */
+      vuint16m2_t p_wide = __riscv_vwsubu_vv_u16m2(b, c, vl);
+      vuint16m2_t pc_wide = __riscv_vwsubu_vv_u16m2(a, c, vl);
+
+      /* Convert to signed for easier manipulation */
+      size_t vl16 = __riscv_vsetvl_e16m2(bpp);
+      vint16m2_t p = __riscv_vreinterpret_v_u16m2_i16m2(p_wide);
+      vint16m2_t pc = __riscv_vreinterpret_v_u16m2_i16m2(pc_wide);
+
+      /* pa = |p| */
+      vbool8_t p_neg_mask = __riscv_vmslt_vx_i16m2_b8(p, 0, vl16);
+      vint16m2_t pa = __riscv_vrsub_vx_i16m2_m(p_neg_mask, p, 0, vl16);
+
+      /* pb = |pc| */
+      vbool8_t pc_neg_mask = __riscv_vmslt_vx_i16m2_b8(pc, 0, vl16);
+      vint16m2_t pb = __riscv_vrsub_vx_i16m2_m(pc_neg_mask, pc, 0, vl16);
+
+      /* pc = |p + pc| */
+      vint16m2_t p_plus_pc = __riscv_vadd_vv_i16m2(p, pc, vl16);
+      vbool8_t p_plus_pc_neg_mask = __riscv_vmslt_vx_i16m2_b8(p_plus_pc, 0, vl16);
+      pc = __riscv_vrsub_vx_i16m2_m(p_plus_pc_neg_mask, p_plus_pc, 0, vl16);
+
+      /*
+       * The key insight is that we want the minimum of pa, pb, pc.
+       * - If pa <= pb and pa <= pc, use a
+       * - Else if pb <= pc, use b
+       * - Else use c
+       */
+
+      /* Find which predictor to use based on minimum absolute difference */
+      vbool8_t pa_le_pb = __riscv_vmsle_vv_i16m2_b8(pa, pb, vl16);
+      vbool8_t pa_le_pc = __riscv_vmsle_vv_i16m2_b8(pa, pc, vl16);
+      vbool8_t pb_le_pc = __riscv_vmsle_vv_i16m2_b8(pb, pc, vl16);
+
+      /* use_a = pa <= pb && pa <= pc */
+      vbool8_t use_a = __riscv_vmand_mm_b8(pa_le_pb, pa_le_pc, vl16);
+
+      /* use_b = !use_a && pb <= pc */
+      vbool8_t not_use_a = __riscv_vmnot_m_b8(use_a, vl16);
+      vbool8_t use_b = __riscv_vmand_mm_b8(not_use_a, pb_le_pc, vl16);
+
+      /* Switch back to e8m1 for final operations */
+      vl = __riscv_vsetvl_e8m1(bpp);
+
+      /* Start with a, then conditionally replace with b or c */
+      vuint8m1_t result = a;
+      result = __riscv_vmerge_vvm_u8m1(result, b, use_b, vl);
+
+      /* use_c = !use_a && !use_b */
+      vbool8_t use_c = __riscv_vmnand_mm_b8(__riscv_vmor_mm_b8(use_a, use_b, vl), __riscv_vmor_mm_b8(use_a, use_b, vl), vl);
+      result = __riscv_vmerge_vvm_u8m1(result, c, use_c, vl);
+
+      /* a = result + x */
+      a = __riscv_vadd_vv_u8m1(result, x, vl);
+
+      /* *row = a */
+      __riscv_vse8_v_u8m1(row, a, vl);
+      row += bpp;
+
+      /* c = b for next iteration */
+      c = b;
+   }
+}
+void
+png_read_filter_row_paeth3_rvv(png_row_infop row_info, png_bytep row,
+    png_const_bytep prev_row)
+{
+   size_t len = row_info->rowbytes;
+
+   png_read_filter_row_paeth_rvv(len, 3, row, prev_row);
+}
+
+void
+png_read_filter_row_paeth4_rvv(png_row_infop row_info, png_bytep row,
+    png_const_bytep prev_row)
+{
+   size_t len = row_info->rowbytes;
+
+   png_read_filter_row_paeth_rvv(len, 4, row, prev_row);
+}
+
+#endif /* PNG_RISCV_RVV_IMPLEMENTATION == 1 */
+#endif /* PNG_READ_SUPPORTED */

riscv/riscv_init.c

@@ -0,0 +1,68 @@
+/* riscv_init.c - RISC-V Vector optimized filter functions
+ *
+ * Copyright (c) 2023 Google LLC
+ * Written by Dragoș Tiselice <dtiselice@google.com>, May 2023.
+ *            Filip Wasil     <f.wasil@samsung.com>, March 2025.
+ * 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"
+
+#ifdef PNG_READ_SUPPORTED
+
+#if PNG_RISCV_RVV_OPT > 0
+
+#include <riscv_vector.h>
+
+#include <signal.h>
+
+#ifndef PNG_RISCV_RVV_FILE
+#  if defined(__linux__)
+#    define PNG_RISCV_RVV_FILE "contrib/riscv-rvv/linux.c"
+#  else
+#    error "No support for run-time RISC-V Vector checking; use compile-time options"
+#  endif
+#endif
+
+static int png_have_rvv();
+#ifdef PNG_RISCV_RVV_FILE
+#  include PNG_RISCV_RVV_FILE
+#endif
+
+#ifndef PNG_ALIGNED_MEMORY_SUPPORTED
+#  error "ALIGNED_MEMORY is required; set: -DPNG_ALIGNED_MEMORY_SUPPORTED"
+#endif
+
+void
+png_init_filter_functions_rvv(png_structp pp, unsigned int bpp)
+{
+   png_debug(1, "in png_init_filter_functions_rvv");
+
+   static volatile sig_atomic_t no_rvv = -1; /* not checked */
+
+   if (no_rvv < 0)
+      no_rvv = !png_have_rvv();
+
+   if (no_rvv)
+      return;
+
+   pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_rvv;
+
+   if (bpp == 3)
+   {
+      pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_rvv;
+      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth3_rvv;
+      pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_rvv;
+   }
+   else if (bpp == 4)
+   {
+      pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_rvv;
+      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth4_rvv;
+      pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_rvv;
+   }
+}
+
+#endif /* PNG_RISCV_RVV_OPT > 0 */
+#endif /* PNG_READ_SUPPORTED */

scripts/cmake/AUTHORS.md

@@ -29,6 +29,7 @@ Author List
  * Jeremy Maitin-Shepard
  * John Bowler
  * Jon Creighton
+ * Joost Nieuwenhuijse
  * Kyle Bentley
  * Martin Storsjö
  * Owen Rudge

scripts/cmake/PNGCheckLibconf.cmake

@@ -0,0 +1,45 @@
+# PNGConfig.cmake
+# Utility functions for configuring and building libpng
+
+# Copyright (c) 2025 Cosmin Truta
+#
+# Use, modification and distribution are subject to
+# the same licensing terms and conditions as libpng.
+# Please see the copyright notice in png.h or visit
+# http://libpng.org/pub/png/src/libpng-LICENSE.txt
+#
+# SPDX-License-Identifier: libpng-2.0
+
+# Check libconf file (pnglibconf.h.* or *.dfa):
+# png_check_libconf([HEADER <file>] [DFA_XTRA <file>])
+function(png_check_libconf)
+  set(options)
+  set(oneValueArgs HEADER DFA_XTRA)
+  set(multiValueArgs)
+
+  cmake_parse_arguments(_CHK "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
+
+  if(_CHK_HEADER AND _CHK_DFA_XTRA)
+    message(FATAL_ERROR "png_check_libconf: Mutually-exclusive arguments: HEADER and DFA_XTRA")
+  endif()
+
+  if(_CHK_HEADER)
+    if(EXISTS "${_CHK_HEADER}")
+      if("x${_CHK_HEADER}" STREQUAL "x${PNG_LIBCONF_HEADER_PREBUILT}")
+        message(STATUS "Using standard libconf header: ${_CHK_HEADER}")
+      else()
+        message(STATUS "Using custom libconf header: ${_CHK_HEADER}")
+      endif()
+    else()
+      message(SEND_ERROR "Could not find libconf header: ${_CHK_HEADER}")
+    endif()
+  else()
+    if("x${_CHK_DFA_XTRA}" STREQUAL "x")
+      message(STATUS "Creating standard configuration")
+    elseif(EXISTS "${_CHK_DFA_XTRA}")
+      message(STATUS "Creating custom configuration with DFA_XTRA file: ${_CHK_DFA_XTRA}")
+    else()
+      message(SEND_ERROR "Could not find DFA_XTRA file: ${_CHK_DFA_XTRA}")
+    endif()
+  endif()
+endfunction()

scripts/cmake/PNGGenConfig.cmake

@@ -18,21 +18,21 @@ function(generate_chk)
   set(options)
   set(oneValueArgs INPUT OUTPUT)
   set(multiValueArgs DEPENDS)
-  cmake_parse_arguments(_GC "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
+  cmake_parse_arguments(_GENCHK "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
-  if(NOT _GC_INPUT)
+  if(NOT _GENCHK_INPUT)
     message(FATAL_ERROR "generate_chk: Missing INPUT argument")
   endif()
-  if(NOT _GC_OUTPUT)
+  if(NOT _GENCHK_OUTPUT)
     message(FATAL_ERROR "generate_chk: Missing OUTPUT argument")
   endif()
 
   # Run genchk.cmake to generate the .chk file.
-  add_custom_command(OUTPUT "${_GC_OUTPUT}"
+  add_custom_command(OUTPUT "${_GENCHK_OUTPUT}"
                      COMMAND "${CMAKE_COMMAND}"
-                             "-DINPUT=${_GC_INPUT}"
+                             "-DINPUT=${_GENCHK_INPUT}"
-                             "-DOUTPUT=${_GC_OUTPUT}"
+                             "-DOUTPUT=${_GENCHK_OUTPUT}"
                              -P "${CMAKE_CURRENT_BINARY_DIR}/scripts/cmake/genchk.cmake"
-                     DEPENDS "${_GC_INPUT}" ${_GC_DEPENDS}
+                     DEPENDS "${_GENCHK_INPUT}" ${_GENCHK_DEPENDS}
                      WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}")
 endfunction()
 
@@ -42,21 +42,21 @@ function(generate_out)
   set(options)
   set(oneValueArgs INPUT OUTPUT)
   set(multiValueArgs DEPENDS)
-  cmake_parse_arguments(_GO "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
+  cmake_parse_arguments(_GENOUT "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
-  if(NOT _GO_INPUT)
+  if(NOT _GENOUT_INPUT)
     message(FATAL_ERROR "generate_out: Missing INPUT argument")
   endif()
-  if(NOT _GO_OUTPUT)
+  if(NOT _GENOUT_OUTPUT)
     message(FATAL_ERROR "generate_out: Missing OUTPUT argument")
   endif()
 
   # Run genout.cmake to generate the .out file.
-  add_custom_command(OUTPUT "${_GO_OUTPUT}"
+  add_custom_command(OUTPUT "${_GENOUT_OUTPUT}"
                      COMMAND "${CMAKE_COMMAND}"
-                             "-DINPUT=${_GO_INPUT}"
+                             "-DINPUT=${_GENOUT_INPUT}"
-                             "-DOUTPUT=${_GO_OUTPUT}"
+                             "-DOUTPUT=${_GENOUT_OUTPUT}"
                              -P "${CMAKE_CURRENT_BINARY_DIR}/scripts/cmake/genout.cmake"
-                     DEPENDS "${_GO_INPUT}" ${_GO_DEPENDS}
+                     DEPENDS "${_GENOUT_INPUT}" ${_GENOUT_DEPENDS}
                      WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}")
 endfunction()
 
@@ -66,17 +66,17 @@ function(generate_source)
   set(options)
   set(oneValueArgs OUTPUT)
   set(multiValueArgs DEPENDS)
-  cmake_parse_arguments(_GSO "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
+  cmake_parse_arguments(_GENSRC "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
-  if(NOT _GSO_OUTPUT)
+  if(NOT _GENSRC_OUTPUT)
     message(FATAL_ERROR "generate_source: Missing OUTPUT argument")
   endif()
 
   # Run gensrc.cmake to generate the source file.
-  add_custom_command(OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/${_GSO_OUTPUT}"
+  add_custom_command(OUTPUT "${_GENSRC_OUTPUT}"
                      COMMAND "${CMAKE_COMMAND}"
-                             "-DOUTPUT=${_GSO_OUTPUT}"
+                             "-DOUTPUT=${_GENSRC_OUTPUT}"
                              -P "${CMAKE_CURRENT_BINARY_DIR}/scripts/cmake/gensrc.cmake"
-                     DEPENDS ${_GSO_DEPENDS}
+                     DEPENDS ${_GENSRC_DEPENDS}
                      WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}")
 endfunction()
 
@@ -86,19 +86,19 @@ function(generate_copy)
   set(options)
   set(oneValueArgs INPUT OUTPUT)
   set(multiValueArgs DEPENDS)
-  cmake_parse_arguments(_GCO "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
+  cmake_parse_arguments(_GENCPY "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
-  if(NOT _GCO_INPUT)
+  if(NOT _GENCPY_INPUT)
     message(FATAL_ERROR "generate_copy: Missing INPUT argument")
   endif()
-  if(NOT _GCO_OUTPUT)
+  if(NOT _GENCPY_OUTPUT)
     message(FATAL_ERROR "generate_copy: Missing OUTPUT argument")
   endif()
 
   # Make a forced file copy, overwriting any pre-existing output file.
-  add_custom_command(OUTPUT "${_GCO_OUTPUT}"
+  add_custom_command(OUTPUT "${_GENCPY_OUTPUT}"
                      COMMAND "${CMAKE_COMMAND}"
-                             -E remove "${_GCO_OUTPUT}"
+                             -E remove "${_GENCPY_OUTPUT}"
                      COMMAND "${CMAKE_COMMAND}"
-                             -E copy "${_GCO_INPUT}" "${_GCO_OUTPUT}"
+                             -E copy "${_GENCPY_INPUT}" "${_GENCPY_OUTPUT}"
-                     DEPENDS "${source}" ${_GCO_DEPENDS})
+                     DEPENDS "${_GENCPY_INPUT}" ${_GENCPY_DEPENDS})
 endfunction()

scripts/cmake/genout.cmake.in

@@ -1,7 +1,7 @@
 # genout.cmake.in
 # Generate .out from .c with awk (generic), based upon the automake logic.
 
-# Copyright (c) 2022-2024 Cosmin Truta
+# Copyright (c) 2022-2025 Cosmin Truta
 # Copyright (c) 2016 Glenn Randers-Pehrson
 # Written by Roger Leigh, 2016
 #
@@ -16,6 +16,7 @@
 set(SRCDIR "@CMAKE_CURRENT_SOURCE_DIR@")
 set(BINDIR "@CMAKE_CURRENT_BINARY_DIR@")
 
+set(APPLE "@APPLE@")
 set(AWK "@AWK@")
 set(CMAKE_C_COMPILER "@CMAKE_C_COMPILER@")
 set(CMAKE_C_FLAGS @CMAKE_C_FLAGS@)

scripts/cmake/gensrc.cmake.in

@@ -21,8 +21,8 @@ set(DFA_XTRA "@DFA_XTRA@")
 set(PNG_PREFIX "@PNG_PREFIX@")
 set(PNGLIB_VERSION "@PNGLIB_VERSION@")
 
-if(OUTPUT STREQUAL "scripts/pnglibconf.c")
+if(OUTPUT MATCHES "(scripts/pnglibconf\\.c)\$")
-  # Generate scripts/pnglibconf.c
+  # Generate "${BINDIR}/scripts/pnglibconf.c"
 
   file(REMOVE "${BINDIR}/pnglibconf.tf6" "${BINDIR}/pnglibconf.tf7")
 
@@ -49,8 +49,8 @@ if(OUTPUT STREQUAL "scripts/pnglibconf.c")
   file(MAKE_DIRECTORY "${BINDIR}/scripts")
   file(RENAME "pnglibconf.tf7" "${BINDIR}/scripts/pnglibconf.c")
 
-elseif(OUTPUT STREQUAL "pnglibconf.c")
+elseif(OUTPUT MATCHES "(pnglibconf\\.c)\$")
-  # Generate pnglibconf.c
+  # Generate "${BINDIR}/pnglibconf.c"
 
   file(REMOVE "${BINDIR}/pnglibconf.tf4" "${BINDIR}/pnglibconf.tf5")
 
@@ -76,10 +76,10 @@ elseif(OUTPUT STREQUAL "pnglibconf.c")
   file(MAKE_DIRECTORY "${BINDIR}/scripts")
   file(RENAME "pnglibconf.tf5" "${BINDIR}/pnglibconf.c")
 
-elseif(OUTPUT STREQUAL "pnglibconf.h")
+elseif(OUTPUT MATCHES "(pnglibconf\\.h)\$")
-  # Generate pnglibconf.h
+  # Generate "${BINDIR}/pnglibconf.h"
 
-  file(REMOVE "${BINDIR}/${OUTPUT}")
+  file(REMOVE "${OUTPUT}")
   if(PNG_PREFIX)
     file(REMOVE "pnglibconf.tf8")
 
@@ -95,20 +95,21 @@ elseif(OUTPUT STREQUAL "pnglibconf.h")
       message(FATAL_ERROR "Failed to generate pnglibconf.tf8")
     endif()
 
-    file(RENAME "pnglibconf.tf8" "${BINDIR}/${OUTPUT}")
+    file(RENAME "pnglibconf.tf8" "${OUTPUT}")
   else()
-    execute_process(COMMAND "${CMAKE_COMMAND}" -E copy "${BINDIR}/pnglibconf.out"
+    execute_process(COMMAND "${CMAKE_COMMAND}" -E copy "pnglibconf.out"
-                                                       "${BINDIR}/${OUTPUT}"
+                                                       "${OUTPUT}"
+                    WORKING_DIRECTORY "${BINDIR}"
                     RESULT_VARIABLE COPY_FAIL)
     if(COPY_FAIL)
       message(FATAL_ERROR "Failed to create pnglibconf.h")
     endif()
   endif()
 
-elseif(OUTPUT STREQUAL "pngprefix.h")
+elseif(OUTPUT MATCHES "(pngprefix\\.h)\$")
-  # Generate pngprefix.h
+  # Generate "${BINDIR}/pngprefix.h"
 
-  file(REMOVE "${BINDIR}/${OUTPUT}")
+  file(REMOVE "${OUTPUT}")
 
   if(PNG_PREFIX)
     file(REMOVE "pngprefix.tf1")
@@ -122,12 +123,12 @@ elseif(OUTPUT STREQUAL "pngprefix.h")
       message(FATAL_ERROR "Failed to generate pngprefix.tf1")
     endif()
 
-    file(RENAME "pngprefix.tf1" "${BINDIR}/${OUTPUT}")
+    file(RENAME "pngprefix.tf1" "${OUTPUT}")
   else()
-    file(WRITE "${BINDIR}/${OUTPUT}" "/* No libpng symbol prefix configured. */")
+    file(WRITE "${OUTPUT}" "/* No libpng symbol prefix configured. */")
   endif()
 
-elseif(OUTPUT STREQUAL "scripts/pnglibconf.h.prebuilt")
+elseif(OUTPUT MATCHES "(scripts/pnglibconf\\.h\\.prebuilt)\$")
   # Generate scripts/pnglibconf.h.prebuilt (fails build)
 
   message(STATUS "Attempting to build scripts/pnglibconf.h.prebuilt")

scripts/libpng-config-head.in

@@ -11,7 +11,7 @@
 
 # Modeled after libxml-config.
 
-version=1.6.47
+version=1.6.51.git
 prefix=""
 libdir=""
 libs=""

scripts/libpng.pc.in

@@ -5,6 +5,6 @@ includedir=@includedir@/libpng16
 
 Name: libpng
 Description: Loads and saves PNG files
-Version: 1.6.47
+Version: 1.6.51.git
 Libs: -L${libdir} -lpng16
 Cflags: -I${includedir}

scripts/makefile.c89

@@ -22,7 +22,8 @@ RM_F = rm -f
 
 # Compiler and linker flags
 NOHWOPT = -DPNG_ARM_NEON_OPT=0 -DPNG_MIPS_MSA_OPT=0 \
-          -DPNG_POWERPC_VSX_OPT=0 -DPNG_INTEL_SSE_OPT=0
+          -DPNG_POWERPC_VSX_OPT=0 -DPNG_INTEL_SSE_OPT=0 \
+          -DPNG_RISCV_RVV_OPT=0
 STDC = -pedantic-errors -std=c89
 WARN = -Wall -Wextra -Wundef
 WARNMORE = -Wcast-align -Wconversion -Wshadow -Wpointer-arith -Wwrite-strings \

scripts/makefile.clang

@@ -21,7 +21,8 @@ RM_F = rm -f
 
 # Compiler and linker flags
 NOHWOPT = -DPNG_ARM_NEON_OPT=0 -DPNG_MIPS_MSA_OPT=0 \
-          -DPNG_POWERPC_VSX_OPT=0 -DPNG_INTEL_SSE_OPT=0
+          -DPNG_POWERPC_VSX_OPT=0 -DPNG_INTEL_SSE_OPT=0 \
+          -DPNG_RISCV_RVV_OPT=0
 STDC = -pedantic-errors # -std=c99
 WARN = -Wall -Wextra -Wundef
 WARNMORE = -Wcast-align -Wconversion -Wshadow -Wpointer-arith -Wwrite-strings \

scripts/makefile.darwin

@@ -28,7 +28,8 @@ RM_F=rm -f
 
 # Compiler and linker flags
 NOHWOPT = -DPNG_ARM_NEON_OPT=0 -DPNG_MIPS_MSA_OPT=0 \
-          -DPNG_POWERPC_VSX_OPT=0 -DPNG_INTEL_SSE_OPT=0
+          -DPNG_POWERPC_VSX_OPT=0 -DPNG_INTEL_SSE_OPT=0 \
+          -DPNG_RISCV_RVV_OPT=0
 STDC = -pedantic-errors
 WARN = -Wall -Wextra -Wundef
 WARNMORE = -Wcast-align -Wconversion -Wshadow -Wpointer-arith -Wwrite-strings \

scripts/makefile.gcc

@@ -21,7 +21,8 @@ RM_F = rm -f
 
 # Compiler and linker flags
 NOHWOPT = -DPNG_ARM_NEON_OPT=0 -DPNG_MIPS_MSA_OPT=0 \
-          -DPNG_POWERPC_VSX_OPT=0 -DPNG_INTEL_SSE_OPT=0
+          -DPNG_POWERPC_VSX_OPT=0 -DPNG_INTEL_SSE_OPT=0 \
+          -DPNG_RISCV_RVV_OPT=0
 STDC = -pedantic-errors # -std=c99
 WARN = -Wall -Wextra -Wundef
 WARNMORE = -Wcast-align -Wconversion -Wshadow -Wpointer-arith -Wwrite-strings \

scripts/makefile.linux

@@ -26,7 +26,8 @@ RM_F=rm -f
 
 # Compiler and linker flags
 NOHWOPT = -DPNG_ARM_NEON_OPT=0 -DPNG_MIPS_MSA_OPT=0 \
-          -DPNG_POWERPC_VSX_OPT=0 -DPNG_INTEL_SSE_OPT=0
+          -DPNG_POWERPC_VSX_OPT=0 -DPNG_INTEL_SSE_OPT=0 \
+          -DPNG_RISCV_RVV_OPT=0
 STDC = -pedantic-errors
 WARN = -Wall -Wextra -Wundef
 WARNMORE = -Wcast-align -Wconversion -Wshadow -Wpointer-arith -Wwrite-strings \

scripts/makefile.msys

@@ -32,7 +32,8 @@ LN_SF = ln -sf
 
 # Compiler and linker flags
 NOHWOPT = -DPNG_ARM_NEON_OPT=0 -DPNG_MIPS_MSA_OPT=0 \
-          -DPNG_POWERPC_VSX_OPT=0 -DPNG_INTEL_SSE_OPT=0
+          -DPNG_POWERPC_VSX_OPT=0 -DPNG_INTEL_SSE_OPT=0 \
+          -DPNG_RISCV_RVV_OPT=0
 STDC = -pedantic-errors
 WARN = -Wall -Wextra -Wundef
 WARNMORE = -Wcast-align -Wconversion -Wshadow -Wpointer-arith -Wwrite-strings \

scripts/makefile.std

@@ -23,7 +23,8 @@ RM_F = rm -f
 AWK = awk
 
 NOHWOPT = -DPNG_ARM_NEON_OPT=0 -DPNG_MIPS_MSA_OPT=0 \
-          -DPNG_POWERPC_VSX_OPT=0 -DPNG_INTEL_SSE_OPT=0
+          -DPNG_POWERPC_VSX_OPT=0 -DPNG_INTEL_SSE_OPT=0 \
+          -DPNG_RISCV_RVV_OPT=0
 DFNFLAGS = # DFNFLAGS contains -D options to use in the libpng build
 DFA_EXTRA = # extra files that can be used to control configuration
 CPPFLAGS = -I$(ZLIBINC) $(NOHWOPT) # -DPNG_DEBUG=5

scripts/pnglibconf.h.prebuilt

@@ -1,6 +1,6 @@
 /* pnglibconf.h - library build configuration */
 
-/* libpng version 1.6.47 */
+/* libpng version 1.6.51.git */
 
 /* Copyright (c) 2018-2025 Cosmin Truta */
 /* Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson */

test-driver

@@ -1,9 +1,9 @@
 #! /bin/sh
 # test-driver - basic testsuite driver script.
 
-scriptversion=2024-06-19.01; # UTC
+scriptversion=2025-06-18.21; # UTC
 
-# Copyright (C) 2011-2024 Free Software Foundation, Inc.
+# Copyright (C) 2011-2025 Free Software Foundation, Inc.
 #
 # 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
@@ -152,9 +152,9 @@ echo ":copy-in-global-log: $gcopy" >> $trs_file
 # Local Variables:
 # mode: shell-script
 # sh-indentation: 2
-# eval: (add-hook 'before-save-hook 'time-stamp)
+# eval: (add-hook 'before-save-hook 'time-stamp nil t)
 # time-stamp-start: "scriptversion="
-# time-stamp-format: "%:y-%02m-%02d.%02H"
+# time-stamp-format: "%Y-%02m-%02d.%02H"
 # time-stamp-time-zone: "UTC0"
 # time-stamp-end: "; # UTC"
 # End: