Harden a vestigial check against overflow inside png_zalloc

Reported-by: Sergio Atienza Pastor, MTP Métodos y Tecnología
Bump version to 1.6.51.git
2025-07-10 18:04:09 +02:00 · 2025-07-03 22:42:11 +03:00 · 2025-07-02 20:24:24 +03:00 · 2025-07-01 23:50:00 +03:00 · 2025-07-01 22:57:36 +03:00 · 2025-06-30 23:46:32 +03:00
94 changed files with 3126 additions and 1202 deletions
--- a/.cmake-format.yaml
+++ b/.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
-  # the default "generating XXX" is a good message already.
+  # TODO:
+  # 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
--- a/.github/workflows/lint.yml
+++ b/.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
--- a/.gitignore
+++ b/.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
-png-fix-itxt
-pngcp
-pngfix
-pngimage
-pngstest
-pngtest
-pngunknown
-pngvalid
-timepng
+# Libpng test programs, scripts and artifacts
+/test-suite.log
+/tests/*.log
+/tests/*.trs
+/png-fix-itxt
+/pngcp
+/pngfix
+/pngimage
+/pngstest
+/pngtest
+/pngunknown
+/pngvalid
+/timepng
--- a/.travis.yml
+++ b/.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'
--- a/39
+++ b/39
@ -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-1.6.47.tar.gz (deflate-compressed)
+ * libpng-1.6.50.tar.xz (LZMA-compressed, recommended)
+ * libpng-1.6.50.tar.gz (deflate-compressed)

 Source files with CRLF line endings (for Windows):

- * lpng1647.7z (LZMA-compressed, recommended)
- * lpng1647.zip (deflate-compressed)
+ * lpng1650.7z (LZMA-compressed, recommended)
+ * 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
-   to the new precedence rules formulated in the latest draft of
-   the PNG Specification.
+ * 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 a latent bug in `png_write_iCCP`.
-   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)
+ * Fixed the CMake file for cross-platform builds that require `libm`.


 Send comments/corrections/commendations to png-mng-implement at lists.sf.net.
--- a/6
+++ b/6
@ -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
--- a/29
+++ b/29
@ -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
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@ -14,13 +14,13 @@
 #
 # SPDX-License-Identifier: libpng-2.0

-cmake_minimum_required(VERSION 3.14)
+cmake_minimum_required(VERSION 3.14...4.0)

 set(PNGLIB_MAJOR 1)
 set(PNGLIB_MINOR 6)
-set(PNGLIB_REVISION 47)
-set(PNGLIB_SUBREVISION 0)
-#set(PNGLIB_SUBREVISION "git")
+set(PNGLIB_REVISION 51)
+#set(PNGLIB_SUBREVISION 0)
+set(PNGLIB_SUBREVISION "git")
 set(PNGLIB_VERSION ${PNGLIB_MAJOR}.${PNGLIB_MINOR}.${PNGLIB_REVISION})
 set(PNGLIB_ABI_VERSION ${PNGLIB_MAJOR}${PNGLIB_MINOR})
 set(PNGLIB_SHARED_VERSION ${PNGLIB_ABI_VERSION}.${PNGLIB_REVISION}.${PNGLIB_SUBREVISION})
@ -30,29 +30,55 @@ project(libpng
        LANGUAGES C ASM)

 include(CheckCSourceCompiles)
+include(CheckLibraryExists)
 include(GNUInstallDirs)

 # Allow the users to specify an application-specific API prefix for libpng
 # vendoring purposes. A standard libpng build should have no such prefix.
-set(PNG_PREFIX ""
+set(PNG_PREFIX
+    ""
    CACHE STRING "Prefix to prepend to the API function names")

 # Allow the users to override the postfix appended to debug library file names.
 # Previously, we used to set CMAKE_DEBUG_POSTFIX globally. That variable should
 # not be cached, however, because doing so would affect all projects processed
 # after libpng, in unexpected and undesirable ways.
-set(PNG_DEBUG_POSTFIX "d"
+set(PNG_DEBUG_POSTFIX
+    "d"
    CACHE STRING "Postfix to append to library file names under the Debug configuration")

 # Allow the users to import their own extra configuration settings.
-set(DFA_XTRA ""
-    CACHE FILEPATH "File containing extra configuration settings")
+# Those settings can be either passed via DFA_XTRA if they are in DFA form
+# (such as "pngusr.dfa"), or via PNG_LIBCONF_HEADER if they are in prebuilt
+# header file form (such as "scripts/pnglibconf.h.prebuilt"), but not both.
+# For platforms such as Android or iOS, or in certain cross-platform build
+# scenarios, having a valid PNG_LIBCONF_HEADER is mandatory.
+set(DFA_XTRA
+    ""
+    CACHE FILEPATH "DFA file containing customized build configuration settings for libpng")
+set(PNG_LIBCONF_HEADER
+    ""
+    CACHE FILEPATH "C header file containing customized build configuration settings for libpng")
+set(PNG_LIBCONF_HEADER_PREBUILT "${CMAKE_CURRENT_SOURCE_DIR}/scripts/pnglibconf.h.prebuilt")
+if(ANDROID OR IOS)
+  set(PNG_LIBCONF_HEADER "${PNG_LIBCONF_HEADER_PREBUILT}")
+endif()
+if((NOT DFA_XTRA STREQUAL "") AND (NOT PNG_LIBCONF_HEADER STREQUAL ""))
+  message(SEND_ERROR "The options DFA_XTRA=\"${DFA_XTRA}\" "
+                     "and PNG_LIBCONF_HEADER=\"${PNG_LIBCONF_HEADER}\" "
+                     "are mutually exclusive")
+endif()

 # Allow the users to switch on/off various library build types.
 option(PNG_SHARED "Build libpng as a shared library" ON)
 option(PNG_STATIC "Build libpng as a static library" ON)
 if(APPLE)
  option(PNG_FRAMEWORK "Build libpng as a framework bundle" ON)
+else()
+  option(PNG_FRAMEWORK "Build libpng as a framework bundle (not available on this platform)" OFF)
+endif()
+if(NOT APPLE AND PNG_FRAMEWORK)
+  message(SEND_ERROR "The option PNG_FRAMEWORK should not be set on this platform")
 endif()

 # Allow the users to switch on/off the auxiliary build and test artifacts.
@ -74,14 +100,13 @@ option(PNG_EXECUTABLES "[Deprecated; please use PNG_TOOLS]" ON)
 if(NOT PNG_EXECUTABLES)
  message(DEPRECATION "The option PNG_EXECUTABLES has been deprecated in favour of PNG_TOOLS")
  if(PNG_TOOLS)
-    message(AUTHOR_WARNING
-            "Setting PNG_TOOLS to ${PNG_EXECUTABLES}, to stay compatible with PNG_EXECUTABLES")
+    message(AUTHOR_WARNING "Setting PNG_TOOLS to ${PNG_EXECUTABLES}, "
+                           "to stay compatible with PNG_EXECUTABLES")
    set(PNG_TOOLS "${PNG_EXECUTABLES}")
  endif()
 endif()

-# Allow the users to configure various compilation options.
-option(PNG_DEBUG "Enable debug output" OFF)
+# Allow the users to switch on/off the use of hardware (SIMD) optimized code.
 option(PNG_HARDWARE_OPTIMIZATIONS "Enable hardware optimizations" ON)

 # Initialize and show the target architecture variable PNG_TARGET_ARCHITECTURE.
@ -104,29 +129,32 @@ message(STATUS "Building for target architecture: ${PNG_TARGET_ARCHITECTURE}")
 option(PNG_BUILD_ZLIB "[Deprecated; please use ZLIB_ROOT]" OFF)
 if(PNG_BUILD_ZLIB)
  if("x${ZLIB_ROOT}" STREQUAL "x")
-    message(SEND_ERROR
-            "The option PNG_BUILD_ZLIB=${PNG_BUILD_ZLIB} is no longer supported; "
+    message(SEND_ERROR "The option PNG_BUILD_ZLIB=${PNG_BUILD_ZLIB} is no longer supported; "
                       "please use ZLIB_ROOT instead")
  else()
-    message(SEND_ERROR
-            "The option PNG_BUILD_ZLIB=${PNG_BUILD_ZLIB} is no longer supported; "
+    message(SEND_ERROR "The option PNG_BUILD_ZLIB=${PNG_BUILD_ZLIB} is no longer supported; "
                       "using ZLIB_ROOT=\"${ZLIB_ROOT}\"")
  endif()
 endif()

+# Find the zlib library.
 find_package(ZLIB REQUIRED)
+set(PNG_LINK_LIBRARIES ZLIB::ZLIB)

-if(UNIX
-   AND NOT (APPLE OR BEOS OR HAIKU)
-   AND NOT EMSCRIPTEN)
-  find_library(M_LIBRARY m)
-  if(M_LIBRARY)
-    set(M_LIBRARY m)
-  else()
-    set(M_LIBRARY "")
+# Find the math library (unless we already know it's not available or
+# not needed).
+if(UNIX AND NOT (APPLE OR BEOS OR HAIKU OR EMSCRIPTEN))
+  check_library_exists(m pow "" PNG_HAVE_LIBM_POW)
 endif()
-else()
-  # libm is not available or not needed.
+if(PNG_HAVE_LIBM_POW)
+  list(APPEND PNG_LINK_LIBRARIES m)
+endif()
+
+# Silence function deprecation warnings on the Windows compilers that might
+# use the MSVC Runtime library headers.
+if(WIN32 AND (CMAKE_C_COMPILER_ID MATCHES "MSVC|Intel|Clang"))
+  add_definitions(-D_CRT_NONSTDC_NO_DEPRECATE)
+  add_definitions(-D_CRT_SECURE_NO_DEPRECATE)
 endif()

 if(PNG_HARDWARE_OPTIMIZATIONS)
@ -135,11 +163,13 @@ if(PNG_HARDWARE_OPTIMIZATIONS)
  if(PNG_TARGET_ARCHITECTURE MATCHES "^(arm|aarch)")
    if(PNG_TARGET_ARCHITECTURE MATCHES "^(arm64|aarch64)")
      set(PNG_ARM_NEON_POSSIBLE_VALUES on off)
-      set(PNG_ARM_NEON "on"
+      set(PNG_ARM_NEON
+          "on"
          CACHE STRING "Enable ARM NEON optimizations: on|off; on is default")
    else()
      set(PNG_ARM_NEON_POSSIBLE_VALUES check on off)
-      set(PNG_ARM_NEON "off"
+      set(PNG_ARM_NEON
+          "off"
          CACHE STRING "Enable ARM NEON optimizations: check|on|off; off is default")
    endif()
    set_property(CACHE PNG_ARM_NEON
@ -165,7 +195,8 @@ if(PNG_HARDWARE_OPTIMIZATIONS)
  # Set definitions and sources for PowerPC.
  if(PNG_TARGET_ARCHITECTURE MATCHES "^(powerpc|ppc64)")
    set(PNG_POWERPC_VSX_POSSIBLE_VALUES on off)
-    set(PNG_POWERPC_VSX "on"
+    set(PNG_POWERPC_VSX
+        "on"
        CACHE STRING "Enable POWERPC VSX optimizations: on|off; on is default")
    set_property(CACHE PNG_POWERPC_VSX
                 PROPERTY STRINGS ${PNG_POWERPC_VSX_POSSIBLE_VALUES})
@ -187,7 +218,8 @@ if(PNG_HARDWARE_OPTIMIZATIONS)
  # Set definitions and sources for Intel.
  if(PNG_TARGET_ARCHITECTURE MATCHES "^(i[3-6]86|x86|amd64)")
    set(PNG_INTEL_SSE_POSSIBLE_VALUES on off)
-    set(PNG_INTEL_SSE "on"
+    set(PNG_INTEL_SSE
+        "on"
        CACHE STRING "Enable INTEL_SSE optimizations: on|off; on is default")
    set_property(CACHE PNG_INTEL_SSE
                 PROPERTY STRINGS ${PNG_INTEL_SSE_POSSIBLE_VALUES})
@ -209,7 +241,8 @@ if(PNG_HARDWARE_OPTIMIZATIONS)
  # Set definitions and sources for MIPS.
  if(PNG_TARGET_ARCHITECTURE MATCHES "^(mipsel|mips64el)")
    set(PNG_MIPS_MSA_POSSIBLE_VALUES on off)
-    set(PNG_MIPS_MSA "on"
+    set(PNG_MIPS_MSA
+        "on"
        CACHE STRING "Enable MIPS_MSA optimizations: on|off; on is default")
    set_property(CACHE PNG_MIPS_MSA
                 PROPERTY STRINGS ${PNG_MIPS_MSA_POSSIBLE_VALUES})
@ -219,7 +252,8 @@ if(PNG_HARDWARE_OPTIMIZATIONS)
    endif()

    set(PNG_MIPS_MMI_POSSIBLE_VALUES on off)
-    set(PNG_MIPS_MMI "on"
+    set(PNG_MIPS_MMI
+        "on"
        CACHE STRING "Enable MIPS_MMI optimizations: on|off; on is default")
    set_property(CACHE PNG_MIPS_MMI
                 PROPERTY STRINGS ${PNG_MIPS_MMI_POSSIBLE_VALUES})
@ -257,7 +291,8 @@ if(PNG_HARDWARE_OPTIMIZATIONS)
  if(PNG_TARGET_ARCHITECTURE MATCHES "^(loongarch)")
    include(CheckCCompilerFlag)
    set(PNG_LOONGARCH_LSX_POSSIBLE_VALUES on off)
-    set(PNG_LOONGARCH_LSX "on"
+    set(PNG_LOONGARCH_LSX
+        "on"
        CACHE STRING "Enable LOONGARCH_LSX optimizations: on|off; on is default")
    set_property(CACHE PNG_LOONGARCH_LSX
                 PROPERTY STRINGS ${PNG_LOONGARCH_LSX_POSSIBLE_VALUES})
@ -265,23 +300,65 @@ if(PNG_HARDWARE_OPTIMIZATIONS)
    if(index EQUAL -1)
      message(FATAL_ERROR "PNG_LOONGARCH_LSX must be one of [${PNG_LOONGARCH_LSX_POSSIBLE_VALUES}]")
    elseif(NOT PNG_LOONGARCH_LSX STREQUAL "off")
-      CHECK_C_COMPILER_FLAG("-mlsx" COMPILER_SUPPORTS_LSX)
+      check_c_compiler_flag("-mlsx" COMPILER_SUPPORTS_LSX)
      if(COMPILER_SUPPORTS_LSX)
        set(libpng_loongarch_sources
            loongarch/loongarch_lsx_init.c
            loongarch/filter_lsx_intrinsics.c)
        set_source_files_properties(${libpng_loongarch_sources}
-                                    PROPERTIES
-                                    COMPILE_FLAGS "-mlsx")
+                                    PROPERTIES COMPILE_FLAGS "-mlsx")
        add_definitions(-DPNG_LOONGARCH_LSX_OPT=1)
      else()
-        message(FATAL_ERROR "Compiler does not support -mlsx option")
+        message(FATAL_ERROR "This compiler does not support the -mlsx option")
      endif()
    else()
      add_definitions(-DPNG_LOONGARCH_LSX_OPT=0)
    endif()
  endif()

+  # Set definitions and sources for RISC-V.
+  if(PNG_TARGET_ARCHITECTURE MATCHES "^(riscv)")
+    include(CheckCCompilerFlag)
+    set(PNG_RISCV_RVV_POSSIBLE_VALUES on off)
+    set(PNG_RISCV_RVV "off"
+      CACHE STRING "Enable RISC-V Vector optimizations: on|off; off is default")
+    set_property(CACHE PNG_RISCV_RVV
+                PROPERTY STRINGS ${PNG_RISCV_RVV_POSSIBLE_VALUES})
+    list(FIND PNG_RISCV_RVV_POSSIBLE_VALUES ${PNG_RISCV_RVV} index)
+    if(index EQUAL -1)
+      message(FATAL_ERROR "PNG_RISCV_RVV must be one of [${PNG_RISCV_RVV_POSSIBLE_VALUES}]")
+    elseif(NOT PNG_RISCV_RVV STREQUAL "off")
+
+      check_c_source_compiles("
+        #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_SUPPORTS_RVV)
+
+      if(NOT COMPILER_SUPPORTS_RVV)
+        message(FATAL_ERROR "Compiler does not support RISC-V Vector extension or its unable to detect it")
+      endif()
+      set(libpng_riscv_sources
+          riscv/filter_rvv_intrinsics.c
+          riscv/riscv_init.c)
+      if(PNG_RISCV_RVV STREQUAL "on")
+        add_definitions(-DPNG_RISCV_RVV_OPT=2)
+      else()
+        add_definitions(-DPNG_RISCV_RVV_OPT=0)
+      endif()
+    else()
+      add_definitions(-DPNG_RISCV_RVV_OPT=0)
+    endif()
+  endif()
+
 else(PNG_HARDWARE_OPTIMIZATIONS)

  # Set definitions and sources for ARM.
@ -309,6 +386,11 @@ else(PNG_HARDWARE_OPTIMIZATIONS)
    add_definitions(-DPNG_LOONGARCH_LSX_OPT=0)
  endif()

+  # Set definitions and sources for RISC-V.
+  if(PNG_TARGET_ARCHITECTURE MATCHES "^(riscv)")
+    add_definitions(-DPNG_RISCV_RVV_OPT=0)
+  endif()
+
 endif(PNG_HARDWARE_OPTIMIZATIONS)

 option(ld-version-script "Enable linker version script" ON)
@ -324,7 +406,8 @@ VERS_2 { global: sym2; main; } VERS_1;
    # Solaris, because of an incompatibility with the Solaris link editor.
    list(APPEND CMAKE_REQUIRED_FLAGS ${CMAKE_SHARED_LIBRARY_C_FLAGS})
  endif()
-  list(APPEND CMAKE_REQUIRED_FLAGS "-Wl,--version-script='${CMAKE_CURRENT_BINARY_DIR}/conftest.map'")
+  list(APPEND CMAKE_REQUIRED_FLAGS
+              "-Wl,--version-script='${CMAKE_CURRENT_BINARY_DIR}/conftest.map'")
  check_c_source_compiles("
 void sym1(void) {}
 void sym2(void) {}
@ -348,6 +431,9 @@ int main(void) { return 0; }
  file(REMOVE "${CMAKE_CURRENT_BINARY_DIR}/conftest.map")
 endif()

+if(PNG_LIBCONF_HEADER STREQUAL "")
+  # No custom configuration header file has been specified, so we build it
+  # from our DFA files and (optionally) out of the user-supplied DFA file.
  # Find an AWK language processor.
  # Start with specific AWK implementations like gawk and nawk, which are
  # known to work with our scripts, then fall back to the system awk.
@ -357,45 +443,60 @@ if(AWK)
  else()
    message(STATUS "Could not find an AWK-compatible program")
  endif()
+endif()

-if(NOT AWK OR (ANDROID OR IOS))
-  # No awk available to generate sources; use pre-built pnglibconf.h
-  configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/pnglibconf.h.prebuilt
-                 ${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h)
+# Include the internal module PNGCheckLibconf.cmake
+include("${CMAKE_CURRENT_SOURCE_DIR}/scripts/cmake/PNGCheckLibconf.cmake")
+
+if(NOT PNG_LIBCONF_HEADER STREQUAL "")
+  # Configure libpng with the user-defined pnglibconf.h file.
+  png_check_libconf(HEADER "${PNG_LIBCONF_HEADER}")
+  configure_file("${PNG_LIBCONF_HEADER}"
+                 "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h"
+                 @ONLY)
+  add_custom_target(png_genfiles)
+elseif(NOT AWK)
+  # No AWK program available to generate pnglibconf.h.
+  # Configure libpng with pnglibconf.h.prebuilt.
+  png_check_libconf(HEADER "${PNG_LIBCONF_HEADER_PREBUILT}")
+  configure_file("${PNG_LIBCONF_HEADER_PREBUILT}"
+                 "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h"
+                 @ONLY)
  add_custom_target(png_genfiles)
 else()
-  # Include the internal module PNGGenConfig.cmake
-  include(${CMAKE_CURRENT_SOURCE_DIR}/scripts/cmake/PNGGenConfig.cmake)
+  png_check_libconf(DFA_XTRA "${DFA_XTRA}")

-  # Copy the awk scripts, converting their line endings to Unix (LF)
-  configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/checksym.awk
-                 ${CMAKE_CURRENT_BINARY_DIR}/scripts/checksym.awk
+  # Include the internal module PNGGenConfig.cmake
+  include("${CMAKE_CURRENT_SOURCE_DIR}/scripts/cmake/PNGGenConfig.cmake")
+
+  # Work around a limitation of various Windows AWK programs that are
+  # unable to process CRLF-terminated AWK scripts.
+  # Copy these AWK scripts to a temporary location, converting their
+  # line endings from Windows (CRLF) to Unix (LF) at the destination.
+  configure_file("${CMAKE_CURRENT_SOURCE_DIR}/scripts/checksym.awk"
+                 "${CMAKE_CURRENT_BINARY_DIR}/scripts/checksym.awk"
                 @ONLY
                 NEWLINE_STYLE LF)
-  configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/options.awk
-                 ${CMAKE_CURRENT_BINARY_DIR}/scripts/options.awk
+  configure_file("${CMAKE_CURRENT_SOURCE_DIR}/scripts/options.awk"
+                 "${CMAKE_CURRENT_BINARY_DIR}/scripts/options.awk"
                 @ONLY
                 NEWLINE_STYLE LF)
-  configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/dfn.awk
-                 ${CMAKE_CURRENT_BINARY_DIR}/scripts/dfn.awk
+  configure_file("${CMAKE_CURRENT_SOURCE_DIR}/scripts/dfn.awk"
+                 "${CMAKE_CURRENT_BINARY_DIR}/scripts/dfn.awk"
                 @ONLY
                 NEWLINE_STYLE LF)

  # Generate scripts/pnglibconf.h
-  generate_source(OUTPUT "scripts/pnglibconf.c"
+  generate_source(OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/pnglibconf.c"
                  DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/scripts/pnglibconf.dfa"
                          "${CMAKE_CURRENT_BINARY_DIR}/scripts/options.awk"
                          "${CMAKE_CURRENT_SOURCE_DIR}/pngconf.h")
-  add_custom_target(png_scripts_pnglibconf_c
-                    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/scripts/pnglibconf.c")

  # Generate pnglibconf.c
-  generate_source(OUTPUT "pnglibconf.c"
+  generate_source(OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.c"
                  DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/scripts/pnglibconf.dfa"
                          "${CMAKE_CURRENT_BINARY_DIR}/scripts/options.awk"
                          "${CMAKE_CURRENT_SOURCE_DIR}/pngconf.h")
-  add_custom_target(pnglibconf_c
-                    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.c")

  if(PNG_PREFIX)
    set(PNGLIBCONF_H_EXTRA_DEPENDS
@ -406,80 +507,53 @@ else()
  endif()

  generate_out(INPUT "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.c"
-               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.out"
-               DEPENDS pnglibconf_c)
-  add_custom_target(pnglibconf_out
-                    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.out")
+               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.out")

  # Generate pnglibconf.h
-  generate_source(OUTPUT "pnglibconf.h"
-                  DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.out" pnglibconf_out
+  generate_source(OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h"
+                  DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.out"
                          ${PNGLIBCONF_H_EXTRA_DEPENDS})
-  add_custom_target(pnglibconf_h
-                    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h")

  generate_out(INPUT "${CMAKE_CURRENT_SOURCE_DIR}/scripts/intprefix.c"
               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/intprefix.out"
-               DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h" pnglibconf_h)
-  add_custom_target(png_scripts_intprefix_out
-                    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/scripts/intprefix.out")
+               DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h")

  generate_out(INPUT "${CMAKE_CURRENT_SOURCE_DIR}/scripts/prefix.c"
               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/prefix.out"
               DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/png.h"
                       "${CMAKE_CURRENT_SOURCE_DIR}/pngconf.h"
-                       "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.out" pnglibconf_out)
-  add_custom_target(png_scripts_prefix_out
-                    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/scripts/prefix.out")
+                       "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.out")

  # Generate pngprefix.h
-  generate_source(OUTPUT "pngprefix.h"
+  generate_source(OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/pngprefix.h"
                  DEPENDS ${PNGPREFIX_H_EXTRA_DEPENDS})
-  add_custom_target(pngprefix_h
-                    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/pngprefix.h")

  generate_out(INPUT "${CMAKE_CURRENT_SOURCE_DIR}/scripts/sym.c"
               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/sym.out"
-               DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h" pnglibconf_h)
-  add_custom_target(png_scripts_sym_out
-                    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/scripts/sym.out")
+               DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h")

  generate_out(INPUT "${CMAKE_CURRENT_SOURCE_DIR}/scripts/symbols.c"
               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.out"
               DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/png.h"
                       "${CMAKE_CURRENT_SOURCE_DIR}/pngconf.h"
                       "${CMAKE_CURRENT_SOURCE_DIR}/scripts/pnglibconf.h.prebuilt")
-  add_custom_target(png_scripts_symbols_out
-                    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.out")

  generate_out(INPUT "${CMAKE_CURRENT_SOURCE_DIR}/scripts/vers.c"
               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/vers.out"
               DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/png.h"
                       "${CMAKE_CURRENT_SOURCE_DIR}/pngconf.h"
-                       "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h" pnglibconf_h)
-  add_custom_target(png_scripts_vers_out
-                    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/scripts/vers.out")
+                       "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h")

  generate_chk(INPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.out"
               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.chk"
-               DEPENDS png_scripts_symbols_out
-                       "${CMAKE_CURRENT_BINARY_DIR}/scripts/checksym.awk"
+               DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/scripts/checksym.awk"
                       "${CMAKE_CURRENT_SOURCE_DIR}/scripts/symbols.def")

-  add_custom_target(png_scripts_symbols_chk
-                    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.chk")
-
  generate_copy(INPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/sym.out"
-                OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/libpng.sym"
-                DEPENDS png_scripts_sym_out)
-  generate_copy(INPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/vers.out"
-                OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/libpng.vers"
-                DEPENDS png_scripts_vers_out)
+                OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/libpng.sym")

-  add_custom_target(png_genvers
-                    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/libpng.vers")
-  add_custom_target(png_gensym
-                    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/libpng.sym")
+  generate_copy(INPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/vers.out"
+                OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/libpng.vers")

  add_custom_target(png_genprebuilt
                    COMMAND "${CMAKE_COMMAND}"
@ -489,20 +563,20 @@ else()

  # A single target handles generation of all generated files.
  add_custom_target(png_genfiles
-                    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/libpng.sym" png_gensym
-                            "${CMAKE_CURRENT_BINARY_DIR}/libpng.vers" png_genvers
-                            "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.c" pnglibconf_c
-                            "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h" pnglibconf_h
-                            "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.out" pnglibconf_out
-                            "${CMAKE_CURRENT_BINARY_DIR}/pngprefix.h" pngprefix_h
-                            "${CMAKE_CURRENT_BINARY_DIR}/scripts/intprefix.out" png_scripts_intprefix_out
-                            "${CMAKE_CURRENT_BINARY_DIR}/scripts/pnglibconf.c" png_scripts_pnglibconf_c
-                            "${CMAKE_CURRENT_BINARY_DIR}/scripts/prefix.out" png_scripts_prefix_out
-                            "${CMAKE_CURRENT_BINARY_DIR}/scripts/sym.out" png_scripts_sym_out
-                            "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.chk" png_scripts_symbols_chk
-                            "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.out" png_scripts_symbols_out
-                            "${CMAKE_CURRENT_BINARY_DIR}/scripts/vers.out" png_scripts_vers_out)
-endif(NOT AWK OR (ANDROID OR IOS))
+                    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/libpng.sym"
+                            "${CMAKE_CURRENT_BINARY_DIR}/libpng.vers"
+                            "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.c"
+                            "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h"
+                            "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.out"
+                            "${CMAKE_CURRENT_BINARY_DIR}/pngprefix.h"
+                            "${CMAKE_CURRENT_BINARY_DIR}/scripts/intprefix.out"
+                            "${CMAKE_CURRENT_BINARY_DIR}/scripts/pnglibconf.c"
+                            "${CMAKE_CURRENT_BINARY_DIR}/scripts/prefix.out"
+                            "${CMAKE_CURRENT_BINARY_DIR}/scripts/sym.out"
+                            "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.chk"
+                            "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.out"
+                            "${CMAKE_CURRENT_BINARY_DIR}/scripts/vers.out")
+endif()

 # List the source code files.
 set(libpng_public_hdrs
@ -516,7 +590,7 @@ set(libpng_private_hdrs
    pnginfo.h
    pngstruct.h
 )
-if(AWK AND NOT (ANDROID OR IOS))
+if(AWK)
  list(APPEND libpng_private_hdrs "${CMAKE_CURRENT_BINARY_DIR}/pngprefix.h")
 endif()
 set(libpng_sources
@ -542,7 +616,9 @@ set(libpng_sources
    ${libpng_mips_sources}
    ${libpng_powerpc_sources}
    ${libpng_loongarch_sources}
+    ${libpng_riscv_sources}
 )
+
 set(pngtest_sources
    pngtest.c
 )
@ -565,15 +641,6 @@ set(png_fix_itxt_sources
    contrib/tools/png-fix-itxt.c
 )

-if(MSVC OR (WIN32 AND (CMAKE_C_COMPILER_ID MATCHES "Clang")))
-  add_definitions(-D_CRT_NONSTDC_NO_DEPRECATE)
-  add_definitions(-D_CRT_SECURE_NO_DEPRECATE)
-endif()
-
-if(PNG_DEBUG)
-  add_definitions(-DPNG_DEBUG)
-endif()
-
 # Now build our targets.

 # Initialize the list of libpng library targets.
@ -601,55 +668,60 @@ if(PNG_SHARED)
  add_library(png_shared SHARED ${libpng_sources})
  add_dependencies(png_shared png_genfiles)
  list(APPEND PNG_LIBRARY_TARGETS png_shared)
-  set_target_properties(png_shared PROPERTIES
-                        OUTPUT_NAME "${PNG_SHARED_OUTPUT_NAME}"
+  set_target_properties(png_shared
+                        PROPERTIES OUTPUT_NAME "${PNG_SHARED_OUTPUT_NAME}"
                                   DEBUG_POSTFIX "${PNG_DEBUG_POSTFIX}"
                                   VERSION "${PNGLIB_SHARED_VERSION}"
                                   SOVERSION "${PNGLIB_ABI_VERSION}")
  if(UNIX AND AWK)
    if(HAVE_LD_VERSION_SCRIPT)
-      set_target_properties(png_shared PROPERTIES
-                            LINK_FLAGS "-Wl,--version-script='${CMAKE_CURRENT_BINARY_DIR}/libpng.vers'")
+      set_target_properties(png_shared
+                            PROPERTIES LINK_FLAGS "-Wl,--version-script='${CMAKE_CURRENT_BINARY_DIR}/libpng.vers'")
    elseif(HAVE_SOLARIS_LD_VERSION_SCRIPT)
-      set_target_properties(png_shared PROPERTIES
-                            LINK_FLAGS "-Wl,-M -Wl,'${CMAKE_CURRENT_BINARY_DIR}/libpng.vers'")
+      set_target_properties(png_shared
+                            PROPERTIES LINK_FLAGS "-Wl,-M -Wl,'${CMAKE_CURRENT_BINARY_DIR}/libpng.vers'")
    endif()
  endif()
  if(APPLE)
    # Avoid CMake's implicit compile definition "png_shared_EXPORTS".
-    set_target_properties(png_shared PROPERTIES DEFINE_SYMBOL "")
+    set_target_properties(png_shared
+                          PROPERTIES DEFINE_SYMBOL "")
  elseif(WIN32)
    # Use the explicit compile definition "PNG_BUILD_DLL" for Windows DLLs.
-    set_target_properties(png_shared PROPERTIES DEFINE_SYMBOL PNG_BUILD_DLL)
+    set_target_properties(png_shared
+                          PROPERTIES DEFINE_SYMBOL PNG_BUILD_DLL)
  endif()
  target_include_directories(png_shared
-                             PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>)
+                             PUBLIC "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>")
  target_include_directories(png_shared
-                             PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}>)
-  target_include_directories(png_shared SYSTEM
-                             INTERFACE $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}/libpng${PNGLIB_ABI_VERSION}>)
-  target_link_libraries(png_shared PUBLIC ZLIB::ZLIB ${M_LIBRARY})
+                             PUBLIC "$<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}>")
+  target_include_directories(png_shared
+                             SYSTEM
+                             INTERFACE "$<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}/libpng${PNGLIB_ABI_VERSION}>")
+  target_link_libraries(png_shared
+                        PUBLIC ${PNG_LINK_LIBRARIES})
 endif()

 if(PNG_STATIC)
  add_library(png_static STATIC ${libpng_sources})
  add_dependencies(png_static png_genfiles)
  list(APPEND PNG_LIBRARY_TARGETS png_static)
-  set_target_properties(png_static PROPERTIES
-                        OUTPUT_NAME "${PNG_STATIC_OUTPUT_NAME}"
+  set_target_properties(png_static
+                        PROPERTIES OUTPUT_NAME "${PNG_STATIC_OUTPUT_NAME}"
                                   DEBUG_POSTFIX "${PNG_DEBUG_POSTFIX}")
  target_include_directories(png_static
-                             PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>)
+                             PUBLIC "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>")
  target_include_directories(png_static
-                             PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}>)
-  target_include_directories(png_static SYSTEM
-                             INTERFACE $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}/libpng${PNGLIB_ABI_VERSION}>)
-  target_link_libraries(png_static PUBLIC ZLIB::ZLIB ${M_LIBRARY})
+                             PUBLIC "$<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}>")
+  target_include_directories(png_static
+                             SYSTEM
+                             INTERFACE "$<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}/libpng${PNGLIB_ABI_VERSION}>")
+  target_link_libraries(png_static
+                        PUBLIC ${PNG_LINK_LIBRARIES})
 endif()

 if(PNG_FRAMEWORK AND NOT APPLE)
-  message(AUTHOR_WARNING
-          "Setting PNG_FRAMEWORK to OFF, as it only applies to Apple systems")
+  message(AUTHOR_WARNING "Setting PNG_FRAMEWORK to OFF, as it only applies to Apple systems")
  set(PNG_FRAMEWORK OFF)
 endif()

@ -657,8 +729,8 @@ if(PNG_FRAMEWORK)
  add_library(png_framework SHARED ${libpng_sources})
  add_dependencies(png_framework png_genfiles)
  list(APPEND PNG_LIBRARY_TARGETS png_framework)
-  set_target_properties(png_framework PROPERTIES
-                        FRAMEWORK TRUE
+  set_target_properties(png_framework
+                        PROPERTIES FRAMEWORK TRUE
                                   FRAMEWORK_VERSION "${PNGLIB_VERSION}"
                                   MACOSX_FRAMEWORK_SHORT_VERSION_STRING "${PNGLIB_MAJOR}.${PNGLIB_MINOR}"
                                   MACOSX_FRAMEWORK_BUNDLE_VERSION "${PNGLIB_VERSION}"
@ -668,14 +740,17 @@ if(PNG_FRAMEWORK)
                                   OUTPUT_NAME "png"
                                   DEBUG_POSTFIX "${PNG_DEBUG_POSTFIX}")
  # Avoid CMake's implicit compile definition "-Dpng_framework_EXPORTS".
-  set_target_properties(png_framework PROPERTIES DEFINE_SYMBOL "")
+  set_target_properties(png_framework
+                        PROPERTIES DEFINE_SYMBOL "")
  target_include_directories(png_framework
-                             PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>)
+                             PUBLIC "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>")
  target_include_directories(png_framework
-                             PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}>)
-  target_include_directories(png_framework SYSTEM
-                             INTERFACE $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}/libpng${PNGLIB_ABI_VERSION}>)
-  target_link_libraries(png_framework PUBLIC ZLIB::ZLIB ${M_LIBRARY})
+                             PUBLIC "$<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}>")
+  target_include_directories(png_framework
+                             SYSTEM
+                             INTERFACE "$<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}/libpng${PNGLIB_ABI_VERSION}>")
+  target_link_libraries(png_framework
+                        PUBLIC ${PNG_LINK_LIBRARIES})
 endif()

 if(NOT PNG_LIBRARY_TARGETS)
@ -688,7 +763,7 @@ if(PNG_TESTS AND PNG_SHARED)
  enable_testing()

  # Include the internal module PNGTest.cmake
-  include(${CMAKE_CURRENT_SOURCE_DIR}/scripts/cmake/PNGTest.cmake)
+  include("${CMAKE_CURRENT_SOURCE_DIR}/scripts/cmake/PNGTest.cmake")

  # Find test PNG files by globbing, but sort lists to ensure
  # consistency between different filesystems.
@ -702,7 +777,8 @@ if(PNG_TESTS AND PNG_SHARED)
  set(PNGTEST_PNG "${CMAKE_CURRENT_SOURCE_DIR}/pngtest.png")

  add_executable(pngtest ${pngtest_sources})
-  target_link_libraries(pngtest PRIVATE png_shared)
+  target_link_libraries(pngtest
+                        PRIVATE png_shared)

  png_add_test(NAME pngtest
               COMMAND pngtest
@ -713,7 +789,8 @@ if(PNG_TESTS AND PNG_SHARED)
               FILES "${TEST_PNG3_PNGS}")

  add_executable(pngvalid ${pngvalid_sources})
-  target_link_libraries(pngvalid PRIVATE png_shared)
+  target_link_libraries(pngvalid
+                        PRIVATE png_shared)

  png_add_test(NAME pngvalid-gamma-16-to-8
               COMMAND pngvalid
@ -759,7 +836,8 @@ if(PNG_TESTS AND PNG_SHARED)
               OPTIONS --transform)

  add_executable(pngstest ${pngstest_sources})
-  target_link_libraries(pngstest PRIVATE png_shared)
+  target_link_libraries(pngstest
+                        PRIVATE png_shared)

  foreach(gamma_type 1.8 linear none sRGB)
    foreach(alpha_type none alpha)
@ -814,7 +892,8 @@ if(PNG_TESTS AND PNG_SHARED)
  endforeach()

  add_executable(pngunknown ${pngunknown_sources})
-  target_link_libraries(pngunknown PRIVATE png_shared)
+  target_link_libraries(pngunknown
+                        PRIVATE png_shared)

  png_add_test(NAME pngunknown-discard
               COMMAND pngunknown
@ -830,7 +909,8 @@ if(PNG_TESTS AND PNG_SHARED)
               FILES "${PNGTEST_PNG}")
  png_add_test(NAME pngunknown-sAPI
               COMMAND pngunknown
-               OPTIONS --strict bKGD=save cHRM=save gAMA=save all=discard iCCP=save sBIT=save sRGB=save
+               OPTIONS --strict
+                       bKGD=save cHRM=save gAMA=save all=discard iCCP=save sBIT=save sRGB=save
               FILES "${PNGTEST_PNG}")
  png_add_test(NAME pngunknown-save
               COMMAND pngunknown
@ -846,7 +926,8 @@ if(PNG_TESTS AND PNG_SHARED)
               FILES "${PNGTEST_PNG}")

  add_executable(pngimage ${pngimage_sources})
-  target_link_libraries(pngimage PRIVATE png_shared)
+  target_link_libraries(pngimage
+                        PRIVATE png_shared)

  png_add_test(NAME pngimage-quick
               COMMAND pngimage
@ -860,11 +941,13 @@ endif()

 if(PNG_SHARED AND PNG_TOOLS)
  add_executable(pngfix ${pngfix_sources})
-  target_link_libraries(pngfix PRIVATE png_shared)
+  target_link_libraries(pngfix
+                        PRIVATE png_shared)
  set(PNG_BIN_TARGETS pngfix)

  add_executable(png-fix-itxt ${png_fix_itxt_sources})
-  target_link_libraries(png-fix-itxt PRIVATE ZLIB::ZLIB ${M_LIBRARY})
+  target_link_libraries(png-fix-itxt
+                        PRIVATE ${PNG_LINK_LIBRARIES})
  list(APPEND PNG_BIN_TARGETS png-fix-itxt)
 endif()

@ -878,12 +961,11 @@ function(create_symlink DEST_FILE)
  # CMake version 3.13.
  cmake_parse_arguments(_SYM "" "FILE;TARGET" "" ${ARGN})
  if(NOT _SYM_FILE AND NOT _SYM_TARGET)
-    message(FATAL_ERROR "create_symlink: Missing FILE or TARGET argument")
+    message(FATAL_ERROR "create_symlink: Missing arguments: FILE or TARGET")
  endif()
  if(_SYM_FILE AND _SYM_TARGET)
-    message(FATAL_ERROR "create_symlink: "
-                        "The arguments FILE (${_SYM_FILE}) and TARGET (${_SYM_TARGET}) "
-                        "are mutually-exclusive")
+    message(FATAL_ERROR "create_symlink: Mutually-exlusive arguments:"
+                        "FILE (${_SYM_FILE}) and TARGET (${_SYM_TARGET})")
  endif()

  if(_SYM_FILE)
@ -892,12 +974,14 @@ function(create_symlink DEST_FILE)
    if(CMAKE_HOST_WIN32 AND NOT CYGWIN)
      execute_process(COMMAND "${CMAKE_COMMAND}"
                              -E copy_if_different
-                              ${_SYM_FILE} ${DEST_FILE}
+                              "${_SYM_FILE}"
+                              "${DEST_FILE}"
                      WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}")
    else()
      execute_process(COMMAND "${CMAKE_COMMAND}"
                              -E create_symlink
-                              ${_SYM_FILE} ${DEST_FILE}
+                              "${_SYM_FILE}"
+                              "${DEST_FILE}"
                      WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}")
    endif()
  endif()
@ -911,28 +995,28 @@ function(create_symlink DEST_FILE)
                         POST_BUILD
                         COMMAND "${CMAKE_COMMAND}"
                                 -E copy_if_different
-                                 $<TARGET_LINKER_FILE_DIR:${_SYM_TARGET}>/$<TARGET_LINKER_FILE_NAME:${_SYM_TARGET}>
-                                 $<TARGET_LINKER_FILE_DIR:${_SYM_TARGET}>/${DEST_FILE})
+                                 "$<TARGET_LINKER_FILE_DIR:${_SYM_TARGET}>/$<TARGET_LINKER_FILE_NAME:${_SYM_TARGET}>"
+                                 "$<TARGET_LINKER_FILE_DIR:${_SYM_TARGET}>/${DEST_FILE}")
    else()
      add_custom_command(TARGET ${_SYM_TARGET}
                         POST_BUILD
                         COMMAND "${CMAKE_COMMAND}"
                                 -E create_symlink
-                                 $<TARGET_LINKER_FILE_NAME:${_SYM_TARGET}>
-                                 $<TARGET_LINKER_FILE_DIR:${_SYM_TARGET}>/${DEST_FILE})
+                                 "$<TARGET_LINKER_FILE_NAME:${_SYM_TARGET}>"
+                                 "$<TARGET_LINKER_FILE_DIR:${_SYM_TARGET}>/${DEST_FILE}")
    endif()
  endif()
 endfunction()

 # Create source generation scripts.
-configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/cmake/genchk.cmake.in
-               ${CMAKE_CURRENT_BINARY_DIR}/scripts/cmake/genchk.cmake
+configure_file("${CMAKE_CURRENT_SOURCE_DIR}/scripts/cmake/genchk.cmake.in"
+               "${CMAKE_CURRENT_BINARY_DIR}/scripts/cmake/genchk.cmake"
               @ONLY)
-configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/cmake/genout.cmake.in
-               ${CMAKE_CURRENT_BINARY_DIR}/scripts/cmake/genout.cmake
+configure_file("${CMAKE_CURRENT_SOURCE_DIR}/scripts/cmake/genout.cmake.in"
+               "${CMAKE_CURRENT_BINARY_DIR}/scripts/cmake/genout.cmake"
               @ONLY)
-configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/cmake/gensrc.cmake.in
-               ${CMAKE_CURRENT_BINARY_DIR}/scripts/cmake/gensrc.cmake
+configure_file("${CMAKE_CURRENT_SOURCE_DIR}/scripts/cmake/gensrc.cmake.in"
+               "${CMAKE_CURRENT_BINARY_DIR}/scripts/cmake/gensrc.cmake"
               @ONLY)

 # libpng is a library so default to 'lib'
@ -945,17 +1029,17 @@ endif()
 # Only do this on Windows for Cygwin - the files don't make much sense
 # outside of a UNIX look-alike.
 if(NOT WIN32 OR CYGWIN OR MINGW)
-  set(prefix      ${CMAKE_INSTALL_PREFIX})
-  set(exec_prefix ${CMAKE_INSTALL_PREFIX})
-  set(libdir      ${CMAKE_INSTALL_FULL_LIBDIR})
-  set(includedir  ${CMAKE_INSTALL_FULL_INCLUDEDIR})
+  set(prefix "${CMAKE_INSTALL_PREFIX}")
+  set(exec_prefix "${CMAKE_INSTALL_PREFIX}")
+  set(libdir "${CMAKE_INSTALL_FULL_LIBDIR}")
+  set(includedir "${CMAKE_INSTALL_FULL_INCLUDEDIR}")
  set(LIBS "-lz -lm")
-  configure_file(${CMAKE_CURRENT_SOURCE_DIR}/libpng.pc.in
-                 ${CMAKE_CURRENT_BINARY_DIR}/libpng${PNGLIB_ABI_VERSION}.pc
+  configure_file("${CMAKE_CURRENT_SOURCE_DIR}/libpng.pc.in"
+                 "${CMAKE_CURRENT_BINARY_DIR}/libpng${PNGLIB_ABI_VERSION}.pc"
                 @ONLY)
  create_symlink(libpng.pc FILE libpng${PNGLIB_ABI_VERSION}.pc)
-  configure_file(${CMAKE_CURRENT_SOURCE_DIR}/libpng-config.in
-                 ${CMAKE_CURRENT_BINARY_DIR}/libpng${PNGLIB_ABI_VERSION}-config
+  configure_file("${CMAKE_CURRENT_SOURCE_DIR}/libpng-config.in"
+                 "${CMAKE_CURRENT_BINARY_DIR}/libpng${PNGLIB_ABI_VERSION}-config"
                 @ONLY)
  create_symlink(libpng-config FILE libpng${PNGLIB_ABI_VERSION}-config)
 endif()
@ -964,72 +1048,72 @@ endif()
 if(NOT SKIP_INSTALL_LIBRARIES AND NOT SKIP_INSTALL_ALL)
  install(TARGETS ${PNG_LIBRARY_TARGETS}
          EXPORT libpng
-          RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
-          LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
-          ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
-          FRAMEWORK DESTINATION ${CMAKE_INSTALL_LIBDIR})
+          RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}"
+          LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}"
+          ARCHIVE DESTINATION "${CMAKE_INSTALL_LIBDIR}"
+          FRAMEWORK DESTINATION "${CMAKE_INSTALL_LIBDIR}")

  if(PNG_SHARED)
    # Create a symlink for libpng.dll.a => libpng16.dll.a on Cygwin
    if(NOT WIN32 OR CYGWIN OR MINGW)
      create_symlink(libpng${CMAKE_SHARED_LIBRARY_SUFFIX} TARGET png_shared)
-      install(FILES $<TARGET_LINKER_FILE_DIR:png_shared>/libpng${CMAKE_SHARED_LIBRARY_SUFFIX}
-              DESTINATION ${CMAKE_INSTALL_LIBDIR})
+      install(FILES "$<TARGET_LINKER_FILE_DIR:png_shared>/libpng${CMAKE_SHARED_LIBRARY_SUFFIX}"
+              DESTINATION "${CMAKE_INSTALL_LIBDIR}")
    endif()
  endif()

  if(PNG_STATIC)
    if(NOT WIN32 OR CYGWIN OR MINGW)
      create_symlink(libpng${CMAKE_STATIC_LIBRARY_SUFFIX} TARGET png_static)
-      install(FILES $<TARGET_LINKER_FILE_DIR:png_static>/libpng${CMAKE_STATIC_LIBRARY_SUFFIX}
-              DESTINATION ${CMAKE_INSTALL_LIBDIR})
+      install(FILES "$<TARGET_LINKER_FILE_DIR:png_static>/libpng${CMAKE_STATIC_LIBRARY_SUFFIX}"
+              DESTINATION "${CMAKE_INSTALL_LIBDIR}")
    endif()
  endif()
 endif()

 if(NOT SKIP_INSTALL_HEADERS AND NOT SKIP_INSTALL_ALL)
  install(FILES ${libpng_public_hdrs}
-          DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
+          DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}")
  install(FILES ${libpng_public_hdrs}
-          DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/libpng${PNGLIB_ABI_VERSION})
+          DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/libpng${PNGLIB_ABI_VERSION}")
 endif()
 if(NOT SKIP_INSTALL_EXECUTABLES AND NOT SKIP_INSTALL_ALL)
  if(NOT WIN32 OR CYGWIN OR MINGW)
-    install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/libpng-config
-            DESTINATION ${CMAKE_INSTALL_BINDIR})
-    install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/libpng${PNGLIB_ABI_VERSION}-config
-            DESTINATION ${CMAKE_INSTALL_BINDIR})
+    install(PROGRAMS "${CMAKE_CURRENT_BINARY_DIR}/libpng-config"
+            DESTINATION "${CMAKE_INSTALL_BINDIR}")
+    install(PROGRAMS "${CMAKE_CURRENT_BINARY_DIR}/libpng${PNGLIB_ABI_VERSION}-config"
+            DESTINATION "${CMAKE_INSTALL_BINDIR}")
  endif()
 endif()

 if(NOT SKIP_INSTALL_PROGRAMS AND NOT SKIP_INSTALL_ALL)
  install(TARGETS ${PNG_BIN_TARGETS}
-          RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
+          RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}")
 endif()

 if(NOT SKIP_INSTALL_FILES AND NOT SKIP_INSTALL_ALL)
  # Install the man pages.
  install(FILES libpng.3 libpngpf.3
-          DESTINATION ${CMAKE_INSTALL_MANDIR}/man3)
+          DESTINATION "${CMAKE_INSTALL_MANDIR}/man3")
  install(FILES png.5
-          DESTINATION ${CMAKE_INSTALL_MANDIR}/man5)
+          DESTINATION "${CMAKE_INSTALL_MANDIR}/man5")
  # Install the pkg-config files.
  if(NOT CMAKE_HOST_WIN32 OR CYGWIN OR MINGW)
-    install(FILES ${CMAKE_CURRENT_BINARY_DIR}/libpng.pc
-            DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig)
-    install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/libpng-config
-            DESTINATION ${CMAKE_INSTALL_BINDIR})
-    install(FILES ${CMAKE_CURRENT_BINARY_DIR}/libpng${PNGLIB_ABI_VERSION}.pc
-            DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig)
-    install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/libpng${PNGLIB_ABI_VERSION}-config
-            DESTINATION ${CMAKE_INSTALL_BINDIR})
+    install(FILES "${CMAKE_CURRENT_BINARY_DIR}/libpng.pc"
+            DESTINATION "${CMAKE_INSTALL_LIBDIR}/pkgconfig")
+    install(PROGRAMS "${CMAKE_CURRENT_BINARY_DIR}/libpng-config"
+            DESTINATION "${CMAKE_INSTALL_BINDIR}")
+    install(FILES "${CMAKE_CURRENT_BINARY_DIR}/libpng${PNGLIB_ABI_VERSION}.pc"
+            DESTINATION "${CMAKE_INSTALL_LIBDIR}/pkgconfig")
+    install(PROGRAMS "${CMAKE_CURRENT_BINARY_DIR}/libpng${PNGLIB_ABI_VERSION}-config"
+            DESTINATION "${CMAKE_INSTALL_BINDIR}")
  endif()
 endif()

 # Create an export file that CMake users can include() to import our targets.
 if(NOT SKIP_INSTALL_EXPORT AND NOT SKIP_INSTALL_ALL)
  install(EXPORT libpng
-          DESTINATION ${CMAKE_INSTALL_LIBDIR}/libpng
+          DESTINATION "${CMAKE_INSTALL_LIBDIR}/libpng"
          FILE libpng${PNGLIB_ABI_VERSION}.cmake)
 endif()

@ -1037,10 +1121,10 @@ endif()
 if(NOT SKIP_INSTALL_CONFIG_FILE AND NOT SKIP_INSTALL_ALL)
  install(TARGETS ${PNG_LIBRARY_TARGETS}
          EXPORT PNGTargets
-          RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
-          LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
-          ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
-          FRAMEWORK DESTINATION ${CMAKE_INSTALL_LIBDIR})
+          RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}"
+          LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}"
+          ARCHIVE DESTINATION "${CMAKE_INSTALL_LIBDIR}"
+          FRAMEWORK DESTINATION "${CMAKE_INSTALL_LIBDIR}")

  include(CMakePackageConfigHelpers)
  write_basic_package_version_file(PNGConfigVersion.cmake
@ -1050,11 +1134,11 @@ if(NOT SKIP_INSTALL_CONFIG_FILE AND NOT SKIP_INSTALL_ALL)
  install(EXPORT PNGTargets
          FILE PNGTargets.cmake
          NAMESPACE PNG::
-          DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/PNG)
+          DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/PNG")

-  install(FILES ${CMAKE_CURRENT_SOURCE_DIR}/scripts/cmake/PNGConfig.cmake
-                ${CMAKE_CURRENT_BINARY_DIR}/PNGConfigVersion.cmake
-          DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/PNG)
+  install(FILES "${CMAKE_CURRENT_SOURCE_DIR}/scripts/cmake/PNGConfig.cmake"
+                "${CMAKE_CURRENT_BINARY_DIR}/PNGConfigVersion.cmake"
+          DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/PNG")
 endif()

 # TODO: Create MSVC import lib for MinGW-compiled shared lib.
--- a/10
+++ b/10
@ -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

--- a/Makefile.am
+++ b/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
--- a/Makefile.in
+++ b/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
-@DO_PNG_PREFIX_TRUE@am__append_12 = -DPNG_PREFIX='@PNG_PREFIX@'
+@PNG_RISCV_RVV_TRUE@am__append_11 = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@rvv.la
+@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) \
@ -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-zip dist-zstd distcheck distclean distclean-compile \
-	distclean-generic distclean-hdr distclean-libtool \
-	distclean-tags distcleancheck distdir distuninstallcheck dvi \
-	dvi-am html html-am info info-am install install-am \
-	install-binPROGRAMS install-binSCRIPTS install-data \
-	install-data-am install-data-hook install-dvi install-dvi-am \
-	install-exec install-exec-am install-exec-hook install-html \
-	install-html-am install-info install-info-am \
+	dist-bzip3 dist-gzip dist-hook dist-lzip dist-shar dist-tarZ \
+	dist-xz dist-zip dist-zstd distcheck distclean \
+	distclean-compile distclean-generic distclean-hdr \
+	distclean-libtool distclean-tags distcleancheck distdir \
+	distuninstallcheck dvi dvi-am html html-am info info-am \
+	install install-am install-binPROGRAMS install-binSCRIPTS \
+	install-data install-data-am install-data-hook install-dvi \
+	install-dvi-am install-exec install-exec-am install-exec-hook \
+	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 \
--- a/6
+++ b/6
@ -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
--- a/aclocal.m4
+++ b/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,
@ -521,7 +521,8 @@ 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_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,
--- a/arm/arm_init.c
+++ b/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
--- a/ci/README.md
+++ b/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
--- a/ci/ci_lint.sh
+++ b/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 "$CI_SHELLCHECK" --version
-    find ./ci -maxdepth 1 -name "*.sh" | {
+    find ./ci -name "ci_*.sh" -not -name "ci_env.*.sh" | {
        local my_file
        while IFS="" read -r my_file
        do
--- a/ci/ci_shellify.sh
+++ b/ci/ci_shellify.sh
@ -1,92 +0,0 @@
-#!/usr/bin/env bash
-set -o errexit -o pipefail -o posix
-
-# Copyright (c) 2019-2024 Cosmin Truta.
-#
-# Use, modification and distribution are subject to the MIT License.
-# Please see the accompanying file LICENSE_MIT.txt
-#
-# SPDX-License-Identifier: MIT
-
-# shellcheck source=ci/lib/ci.lib.sh
-source "$(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 "$@"
--- a/ci/ci_verify_cmake.sh
+++ b/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
--- a/ci/ci_verify_configure.sh
+++ b/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
--- a/ci/ci_verify_makefiles.sh
+++ b/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
--- a/ci/ci_verify_version.sh
+++ b/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 {
-    [[ -f $CI_SCRIPT_DIR/ci_shellify.sh ]] || {
-        ci_err_internal "missing script: '$CI_SCRIPT_DIR/ci_shellify.sh'"
-    }
-}
+# Declare the global environments collected from various sources.
+declare CI_ENV_LIBPNG_VER        # collected from png.h
+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" "$CI_SCRIPT_DIR/ci_shellify.sh" "$@"
+    "$BASH" "$my_script" "$@"
    echo "$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_init_shellify
-    my_env_libpng_ver="$(ci_run_shellify png.h)"
-    echo "$my_env_libpng_ver"
-    my_env_autoconf_ver="$(ci_run_shellify configure.ac)"
-    echo "$my_env_autoconf_ver"
-    my_env_cmake_ver="$(ci_run_shellify CMakeLists.txt)"
-    echo "$my_env_cmake_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}"
+    CI_ENV_LIBPNG_VER="$(ci_run_shellify --c png.h)"
+    echo "$CI_ENV_LIBPNG_VER"
+    CI_ENV_AUTOCONF_VER="$(ci_run_shellify --autoconf configure.ac)"
+    echo "$CI_ENV_AUTOCONF_VER"
+    CI_ENV_CMAKE_VER="$(ci_run_shellify --cmake CMakeLists.txt)"
+    echo "$CI_ENV_CMAKE_VER"
+    CI_ENV_LIBPNGCONFIG_VER="$(ci_run_shellify --shell scripts/libpng-config-head.in)"
+    echo "$CI_ENV_LIBPNGCONFIG_VER"
+}
+
+# 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 ##"
-    eval "$my_env_autoconf_ver"
+    ci_info "## VERIFYING: version definitions in 'configure.ac' ##"
+    eval "$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 ##"
-    eval "$my_env_cmake_ver"
+    ci_info "## VERIFYING: version definitions in 'CMakeLists.txt' ##"
+    eval "$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 {
--- a/ci/lib/ci.lib.sh
+++ b/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
--- a/ci/libexec/ci_shellify_autoconf.sh
+++ b/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 <"$1"
+}
+
+main "$@"
--- a/ci/libexec/ci_shellify_c.sh
+++ b/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 <"$1"
+}
+
+main "$@"
--- a/ci/libexec/ci_shellify_cmake.sh
+++ b/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 <"$1"
+}
+
+main "$@"
--- a/ci/libexec/ci_shellify_shell.sh
+++ b/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 <"$1"
+}
+
+main "$@"
--- a/33
+++ b/33
@ -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
-# take place.
+# type is listed in (the comma separated) UNNEEDED_CONVERSIONS, no
+# conversion will take place.
 func_file_conv ()
 {
  file=$1
@ -51,9 +51,20 @@ func_file_conv ()
 	# lazily determine how to convert abs files
 	case `uname -s` in
 	  MINGW*)
+	    if test -n "$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/"\(.*\) " *$/\1/'`
 	  ;;
-	cygwin/* | msys/*)
-	  file=`cygpath -m "$file" || echo "$file"`
+	cygwin/*)
+	  file=`cygpath -w "$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:
--- a/config.guess
+++ b/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
@ -634,6 +634,7 @@ EOF
 		sed 's/^		//' << EOF > "$dummy.c"
 		#include <sys/systemcfg.h>

+		int
 		main ()
 			{
 			if (!__power_pc())
@ -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)
--- a/config.h.in
+++ b/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. */
--- a/config.sub
+++ b/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 $maybe_os in
-			nto-qnx* | linux-* | uclinux-uclibc* \
-			| uclinux-gnu* | kfreebsd*-gnu* | knetbsd*-gnu* | netbsd*-gnu* \
-			| netbsd*-eabi* | kopensolaris*-gnu* | cloudabi*-eabi* \
-			| storm-chaos* | os2-emx* | rtmk-nova* | managarm-* \
+			  cloudabi*-eabi* \
+			| kfreebsd*-gnu* \
+			| knetbsd*-gnu* \
+			| kopensolaris*-gnu* \
+			| linux-* \
+			| managarm-* \
+			| netbsd*-eabi* \
+			| netbsd*-gnu* \
+			| nto-qnx* \
+			| os2-emx* \
+			| rtmk-nova* \
+			| storm-chaos* \
+			| uclinux-gnu* \
+			| uclinux-uclibc* \
 			| windows-* )
 				basic_machine=$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 \
-	      | 3300-motorola | delta-motorola)
+	delta | 3300 | delta-motorola | 3300-motorola | motorola-delta | motorola-3300)
 		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
-	# some cases the only manufacturer, in others, it is the most popular.
+	# Here we handle the default manufacturer of certain CPU types in canonical form.
+	# 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=${basic_os:-linux-gnueabihf}
 		;;
-	dpx20-unknown | dpx20-bull)
-		cpu=rs6000
-		vendor=bull
+
+	# Normalized CPU+vendor pairs that imply an OS, if not otherwise specified
+	m68k-isi)
+		basic_os=${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] \
-			| alpha64 | alpha64ev[4-8] | alpha64ev56 | alpha64ev6[78] \
-			| alphapca5[67] | alpha64pca5[67] \
+			| alpha \
+			| alpha64 \
+			| alpha64ev56 \
+			| alpha64ev6[78] \
+			| alpha64ev[4-8] \
+			| alpha64pca5[67] \
+			| alphaev56 \
+			| alphaev6[78] \
+			| alphaev[4-8] \
+			| alphapca5[67] \
 			| am33_2.0 \
 			| amdgcn \
-			| arc | arceb | arc32 | arc64 \
-			| arm | arm[lb]e | arme[lb] | armv* \
-			| avr | avr32 \
+			| arc \
+			| arc32 \
+			| arc64 \
+			| arceb \
+			| arm \
+			| arm64e \
+			| arm64ec \
+			| arm[lb]e \
+			| arme[lb] \
+			| armv* \
 			| asmjs \
+			| avr \
+			| avr32 \
 			| ba \
-			| be32 | be64 \
-			| bfin | bpf | bs2000 \
-			| c[123]* | c30 | [cjt]90 | c4x \
-			| c8051 | clipper | craynv | csky | cydra \
-			| d10v | d30v | dlx | dsp16xx \
-			| e2k | elxsi | epiphany \
-			| f30[01] | f700 | fido | fr30 | frv | ft32 | fx80 \
-			| javascript \
-			| h8300 | h8500 \
-			| hppa | hppa1.[01] | hppa2.0 | hppa2.0[nw] | hppa64 \
+			| be32 \
+			| be64 \
+			| bfin \
+			| bpf \
+			| bs2000 \
+			| c30 \
+			| c4x \
+			| c8051 \
+			| c[123]* \
+			| 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 \
-			| ip2k | iq2000 \
+			| hppa \
+			| 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 \
-			| m32c | m32r | m32rle \
-			| m5200 | m68000 | m680[012346]0 | m68360 | m683?2 | m68k \
-			| m6811 | m68hc11 | m6812 | m68hc12 | m68hcs12x \
-			| m88110 | m88k | maxq | mb | mcore | mep | metag \
-			| microblaze | microblazeel \
+			| loongarch32 \
+			| loongarch64 \
+			| m32c \
+			| m32r \
+			| m32rle \
+			| 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 \
-			| none | np1 | ns16k | ns32k | nvptx \
+			| nios \
+			| nios2 \
+			| nios2eb \
+			| nios2el \
+			| none \
+			| np1 \
+			| ns16k \
+			| ns32k \
+			| nvptx \
 			| open8 \
 			| or1k* \
 			| or32 \
 			| orion \
+			| pdp10 \
+			| pdp11 \
 			| picochip \
-			| pdp10 | pdp11 | pj | pjl | pn | power \
-			| powerpc | powerpc64 | powerpc64le | powerpcle | powerpcspe \
+			| pj \
+			| pjl \
+			| pn \
+			| power \
+			| powerpc \
+			| powerpc64 \
+			| powerpc64le \
+			| powerpcle \
+			| powerpcspe \
 			| pru \
 			| pyramid \
-			| riscv | riscv32 | riscv32be | riscv64 | riscv64be \
-			| rl78 | romp | rs6000 | rx \
-			| s390 | s390x \
+			| riscv \
+			| riscv32 \
+			| riscv32be \
+			| riscv64 \
+			| riscv64be \
+			| rl78 \
+			| romp \
+			| rs6000 \
+			| rx \
+			| s390 \
+			| s390x \
 			| score \
-			| sh | shl \
-			| sh[1234] | sh[24]a | sh[24]ae[lb] | sh[23]e | she[lb] | sh[lb]e \
-			| sh[1234]e[lb] |  sh[12345][lb]e | sh[23]ele | sh64 | sh64le \
-			| sparc | sparc64 | sparc64b | sparc64v | sparc86x | sparclet \
+			| sh \
+			| sh64 \
+			| sh64le \
+			| 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 \
-			| xstormy16 | xtensa* \
+			| x86 \
+			| 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$|convergent|'`
+		;;
+	uts*)
 		os=sysv
 		;;
 	nova*)
-		os=rtmk-nova
-		;;
-	ns2)
-		os=nextstep2
+		kernel=rtmk
+		os=nova
 		;;
 	# Preserve the version number of sinix5.
 	sinix5.*)
 		os=`echo "$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* \
-	     | *vms* | esix* | aix* | cnk* | sunos | sunos[34]* \
-	     | hpux* | unos* | osf* | luna* | dgux* | auroraux* | solaris* \
-	     | sym* |  plan9* | psp* | sim* | xray* | os68k* | v88r* \
-	     | hiux* | abug | nacl* | netware* | windows* \
-	     | os9* | macos* | osx* | ios* | tvos* | watchos* \
-	     | mpw* | magic* | mmixware* | mon960* | lnews* \
-	     | amigaos* | amigados* | msdos* | newsos* | unicos* | aof* \
-	     | aos* | aros* | cloudabi* | sortix* | twizzler* \
-	     | nindy* | vxsim* | vxworks* | ebmon* | hms* | mvs* \
-	     | clix* | riscos* | uniplus* | iris* | isc* | rtu* | xenix* \
-	     | mirbsd* | netbsd* | dicos* | openedition* | ose* \
-	     | bitrig* | openbsd* | secbsd* | solidbsd* | libertybsd* | os108* \
-	     | ekkobsd* | freebsd* | riscix* | lynxos* | os400* \
-	     | bosx* | nextstep* | cxux* | oabi* \
-	     | ptx* | ecoff* | winnt* | domain* | vsta* \
-	     | udi* | lites* | ieee* | go32* | aux* | hcos* \
-	     | chorusrdb* | cegcc* | glidix* | serenity* \
-	     | cygwin* | msys* | moss* | proelf* | rtems* \
-	     | midipix* | mingw32* | mingw64* | mint* \
-	     | uxpv* | beos* | mpeix* | udk* | moxiebox* \
-	     | interix* | uwin* | mks* | rhapsody* | darwin* \
-	     | openstep* | oskit* | conix* | pw32* | nonstopux* \
-	     | storm-chaos* | tops10* | tenex* | tops20* | its* \
-	     | os2* | vos* | palmos* | uclinux* | nucleus* | morphos* \
-	     | scout* | superux* | sysv* | rtmk* | tpf* | windiss* \
-	     | powermax* | dnix* | nx6 | nx7 | sei* | dragonfly* \
-	     | skyos* | haiku* | rdos* | toppers* | drops* | es* \
-	     | onefs* | tirtos* | phoenix* | fuchsia* | redox* | bme* \
-	     | midnightbsd* | amdhsa* | unleashed* | emscripten* | wasi* \
-	     | nsk* | powerunix* | genode* | zvmoe* | qnx* | emx* | zephyr* \
-	     | fiwix* | mlibc* | cos* | mbr* | ironclad* )
+	  abug \
+	| aix* \
+	| amdhsa* \
+	| amigados* \
+	| amigaos* \
+	| android* \
+	| aof* \
+	| aos* \
+	| aros* \
+	| atheos* \
+	| auroraux* \
+	| aux* \
+	| beos* \
+	| bitrig* \
+	| bme* \
+	| bosx* \
+	| bsd* \
+	| cegcc* \
+	| chorusos* \
+	| chorusrdb* \
+	| clix* \
+	| cloudabi* \
+	| cnk* \
+	| conix* \
+	| cos* \
+	| cxux* \
+	| cygwin* \
+	| darwin* \
+	| dgux* \
+	| dicos* \
+	| dnix* \
+	| 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*)
--- a/277
+++ b/277
@ -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_STRING='libpng 1.6.47'
+PACKAGE_VERSION='1.6.51.git'
+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\\"

--- a/configure.ac
+++ b/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
--- a/contrib/conftest/read-full.dfa
+++ b/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
--- a/contrib/conftest/write-full.dfa
+++ b/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
--- a/contrib/examples/.clang-format
+++ b/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
+...
--- a/contrib/examples/iccfrompng.c
+++ b/contrib/examples/iccfrompng.c
@ -26,8 +26,9 @@

 #include <png.h>

-#if defined(PNG_READ_SUPPORTED) && defined(PNG_STDIO_SUPPORTED) && \
-    defined (PNG_iCCP_SUPPORTED)
+#if !defined(PNG_iCCP_SUPPORTED) || !defined(PNG_READ_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;

@ -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;
 }

@ -182,4 +187,3 @@ main(int argc, char **argv)
   /* Exit code is true if any extract succeeds */
   return extracted == 0;
 }
-#endif /* READ && STDIO && iCCP */
--- a/contrib/examples/pngpixel.c
+++ b/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
- * interlace passes directly looking for the required pixel.
+ * png_set_interlace_handling() is not called and, instead, the code handles
+ * the interlace passes directly looking for the required pixel.
 */
 #include <stdlib.h>
 #include <stdio.h>
@ -27,16 +27,19 @@
 */
 #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)
 {
-   /* PNG images can be up to 2^31 pixels wide, but this means they can be up to
-    * 2^37 bits wide (for a 64-bit pixel - the largest possible) and hence 2^34
-    * bytes wide.  Since the row fitted into memory, however, the following must
+   /* 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 bytes wide.  Since the row fitted into memory, the following must
    * work:
    */
   png_uint_32 bit_offset_hi = bit_depth * ((x >> 6) * channels);
@ -47,8 +50,8 @@ component(png_const_bytep row, png_uint_32 x, unsigned int c,
   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
-    * first, so:
+    * bits of the byte, and into two bytes for 16-bit values with the high
+    * 8 bits first, so:
    */
   switch (bit_depth)
   {
@ -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 &&
-                  trans_alpha != NULL)
+                                 NULL) & PNG_INFO_tRNS) &&
+                   (num_trans > 0) &&
+                   (trans_alpha != NULL))
                  printf("INDEXED %u = %d %d %d %d\n", index,
                         palette[index].red, palette[index].green,
                         palette[index].blue,
                         index < num_trans ? trans_alpha[index] : 255);

               else /* no transparency */
-                  printf("INDEXED %u = %d %d %d\n", index,
-                     palette[index].red, palette[index].green,
-                     palette[index].blue);
+                  printf("INDEXED %u = %d %d %d\n", index, palette[index].red,
+                         palette[index].green, palette[index].blue);
            }

            else
@ -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
@ -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,
-            NULL, NULL, NULL);
+         png_structp png_ptr =
+            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
-                   * libpng initialization functions.  Sometimes libpng is
-                   * compiled without stdio support (it can be difficult to do
-                   * in some environments); in that case you will have to write
-                   * your own read callback to read data from the (FILE*).
+                  /* Now associate the recently opened FILE object with the
+                   * default libpng initialization functions.  Sometimes libpng
+                   * is compiled without stdio support (it can be difficult to
+                   * do in some environments); in that case you will have to
+                   * write your own read callback to read data from the stream.
                   */
                  png_init_io(png_ptr, f);

@ -202,16 +208,16 @@ 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,
-                     info_ptr));
+                  row =
+                     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
-                   * png_get_IHDR, if this fails we can now use 'png_error' to
+                  /* All the information we need is in the header returned by
+                   * 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,
@ -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;
-                              px < width; px += xstep, ++ppx) if (x == px)
+                           if (y == py)
                           {
-                              /* 'ppx' is the index of the pixel in the row
-                               * buffer.
+                              for (px = xstart, ppx = 0;
+                                   px < width;
+                                   px += xstep, ++ppx)
+                              {
+                                 if (x == px)
+                                 {
+                                    /* 'ppx' is the index of the pixel in the
+                                     * row buffer.
                                     */
-                              print_pixel(png_ptr, info_ptr, row_tmp, ppx);
+                                    print_pixel(png_ptr, info_ptr, row_tmp,
+                                                ppx);

                                    /* Now terminate the loops early - we have
                                     * found and handled the required data.
                                     */
                                    goto pass_loop_end;
                                 } /* 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 */
--- a/contrib/examples/pngtopng.c
+++ b/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
- * handling added.  See example.c for more comments.
+ * This sample code is just the code from 'example.c' with some error handling
+ * 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;

@ -49,11 +54,11 @@ int main(int argc, const char **argv)
         if (buffer != NULL)
         {
            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],
-                  0/*convert_to_8bit*/, buffer, 0/*row_stride*/,
-                  NULL/*colormap*/))
+               if (png_image_write_to_file(
+                      &image, argv[2], 0 /*convert_to_8bit*/, buffer,
+                      0 /*row_stride*/, NULL /*colormap*/))
                  result = 0;

               else
@ -93,4 +98,3 @@ int main(int argc, const char **argv)

   return result;
 }
-#endif /* READ && WRITE */
--- a/contrib/examples/simpleover.c
+++ b/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
- * RGBA intermediates.  This involves doing the correct 'over' composition to
- * combine the alpha channels and corresponding data.
+ * information, and composite them together to produce one or more 16-bit
+ * linear RGBA intermediates.  This involves doing the 'over' compositing
+ * 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
- * on the command line) being at the bottom and the last on the top.
+ * be regarded as being layered one on top of the other with the first
+ * (leftmost on the command line) being at the bottom and the last on the top.
 */
 #include <stddef.h>
 #include <stdlib.h>
@ -44,10 +44,13 @@
 */
 #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;
   unsigned int width;
@ -59,18 +62,21 @@ struct sprite {
 #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 {
+   do
+   {
      unsigned int t = x + (x >> 16) /*+ (x >> 31)*/ + r;
      double v = x, errtest;

-         if (t < x) {
+      if (t < x)
+      {
         fprintf(stderr, "overflow: %u+%u -> %u\n", x, r, t);
         return 1;
      }
@ -80,18 +86,19 @@ int main(void) {
      t >>= 16;
      errtest -= t;

-         if (errtest > err) {
+      if (errtest > err)
+      {
         err = errtest;
         xerr = x;

-            if (errtest >= .5) {
+         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);

@ -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) &&
-       (x_offset < 0 || (unsigned)/*SAFE*/x_offset < sprite->width))
+   if ((y_offset < 0 || /*SAFE*/ (unsigned)y_offset < sprite->height) &&
+       (x_offset < 0 || /*SAFE*/ (unsigned)x_offset < sprite->width))
   {
      unsigned int y = 0;

@ -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[2] = in_pixel[2],
+               {
+                  out_pixel[0] = in_pixel[0];
+                  out_pixel[1] = in_pixel[1];
+                  out_pixel[2] = in_pixel[2];
                  out_pixel[3] = in_pixel[3];
               }
            }
-         while (++x < image->width);
-      }
-      while (++y < image->height);
+         } while (++x < image->width);
+      } while (++y < image->height);
   }
 }

@ -225,8 +232,7 @@ create_sprite(struct sprite *sprite, int *argc, const char ***argv)
            if (buffer != NULL)
            {
               if (png_image_finish_read(&image, NULL /*background*/, buffer,
-                  0/*row_stride*/,
-                  NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP*/))
+                                         0 /*row_stride*/, NULL /*colormap*/))
               {
                  /* This is the place where the Porter-Duff 'Over' operator
                   * needs to be done by this code.  In fact, any image
@ -291,7 +297,8 @@ create_sprite(struct sprite *sprite, int *argc, const char ***argv)
      save.colormap_entries = 0;

      if (png_image_write_to_stdio(&save, sprite->file, 1 /*convert_to_8_bit*/,
-          sprite->buffer, 0/*row_stride*/, NULL/*colormap*/))
+                                   sprite->buffer, 0 /*row_stride*/,
+                                   NULL /*colormap*/))
      {
         /* Success; the buffer is no longer needed: */
         free(sprite->buffer);
@ -305,7 +312,8 @@ create_sprite(struct sprite *sprite, int *argc, const char ***argv)
   }

   else
-      fprintf(stderr, "simpleover: sprite %s: could not allocate tmpfile: %s\n",
+      fprintf(stderr,
+              "simpleover: sprite %s: could not allocate tmpfile: %s\n",
              sprite->name, strerror(errno));

   return 0; /* fail */
@ -334,8 +342,8 @@ add_sprite(png_imagep output, png_bytep out_buf, struct sprite *sprite,
          * will fit.
          */
         if (x < 0 || y < 0 ||
-             (unsigned)/*SAFE*/x >= output->width ||
-             (unsigned)/*SAFE*/y >= output->height ||
+             /*SAFE*/ (unsigned)x >= output->width ||
+             /*SAFE*/ (unsigned)y >= output->height ||
             sprite->width > output->width - x ||
             sprite->height > output->height - y)
         {
@ -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(
+                      &in, NULL /*background*/,
                      out_buf + (y * output->width + x) * 3 /*RGB*/,
-                  output->width*3/*row_stride*/,
-                  NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP*/))
+                      output->width * 3 /*row_stride*/, NULL /*colormap*/))
               {
                  ++*argv, --*argc;
                  continue;
@ -412,12 +420,14 @@ 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],
+                       "--sprite=%u,%u,%" str(sprite_name_chars) "s%c",
                       &sprites[nsprites].width, &sprites[nsprites].height,
                       sprites[nsprites].name, &tombstone);

            if ((n == 2 || n == 3) &&
-                sprites[nsprites].width > 0 && sprites[nsprites].height > 0)
+                (sprites[nsprites].width > 0) &&
+                (sprites[nsprites].height > 0))
            {
               size_t buf_size, tmp;

@ -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;
            }
         }
@ -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 */

@ -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,
-                        0/*convert_to_8bit*/, buffer, 0/*row_stride*/,
-                        NULL/*colormap*/)) ||
+                       png_image_write_to_file(
+                          &image, output, 0 /*convert_to_8bit*/, buffer,
+                          0 /*row_stride*/, NULL /*colormap*/)) ||
                      (output == NULL &&
-                       png_image_write_to_stdio(&image, stdout,
-                        0/*convert_to_8bit*/, buffer, 0/*row_stride*/,
-                        NULL/*colormap*/)))
+                       png_image_write_to_stdio(
+                          &image, stdout, 0 /*convert_to_8bit*/, buffer,
+                          0 /*row_stride*/, NULL /*colormap*/)))
                     result = 0;

                  else
                     fprintf(stderr, "simpleover: write %s: %s\n",
-                        output == NULL ? "stdout" : output, image.message);
+                             output == NULL ? "stdout" : output,
+                             image.message);
               }

               /* else simpleover_process writes an error message */
@ -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"
-         "     operation at offset (x,y) in the sprite (defaulting to (0,0)).\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"
         "     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 */
--- a/contrib/libtests/pngstest.c
+++ b/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)
--- a/contrib/riscv-rvv/README
+++ b/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.
--- a/contrib/riscv-rvv/linux.c
+++ b/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
+}
--- a/contrib/tools/pngfix.c
+++ b/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
--- a/8
+++ b/8
@ -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:
--- a/example.c
+++ b/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
- * the particular png_image_read_from_ function you call at the start.
- * Likewise, on write, you can write to a FILE* if your system supports it.
- * Check the macro PNG_STDIO_SUPPORTED to see if stdio support has been
- * included in your libpng build.
+ * on systems that support <stdio.h>, from a FILE object.  This is controlled
+ * by the particular png_image_begin_read_from_ function you call at the start.
+ * Likewise, on write, you can write to a FILE object if your system supports
+ * <stdio.h>.  The macro PNG_STDIO_SUPPORTED indicates if stdio is available
+ * 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
--- a/6
+++ b/6
@ -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:
--- a/libpng-manual.txt
+++ b/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/>.
-It is technically equivalent
-to the PNG specification (second edition) but has some additional material.
+<https://www.libpng.org/pub/png/spec/1.2/>.
+It is technically equivalent to the PNG specification (Second Edition)
+but has some additional material.

 The PNG-1.0 specification is available as RFC 2083 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
@ -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
--- a/libpng.3
+++ b/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
@ -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/>.
-It is technically equivalent
-to the PNG specification (second edition) but has some additional material.
+<https://www.libpng.org/pub/png/spec/1.2/>.
+It is technically equivalent to the PNG specification (Second Edition)
+but has some additional material.

 The PNG-1.0 specification is available as RFC 2083 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
@ -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
--- a/libpngpf.3
+++ b/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
-(private functions)
+libpng \- Portable Network Graphics (PNG) Reference Library 1.6.50

 .SH SYNOPSIS
-\fB#include \fI"pngpriv.h"
-
-\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.
+\fB#include "pngpriv.h"\fP

 .SH DESCRIPTION
-The functions previously listed here are used privately by libpng and are not
-available for use by applications.  They are not "exported" to applications
-using shared libraries.
+As of libpng version 1.5.1, this manual is no longer maintained.  The private
+function prototypes, declared in private header files, should not be accessed
+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
--- a/mips/mips_init.c
+++ b/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
--- a/8
+++ b/8
@ -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:
--- a/png.5
+++ b/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):
-Glenn Randers-Pehrson and others.
+Portable Network Graphics (PNG) Specification Version 1.2 (11 August 1999):
+Glenn Randers-Pehrson et al.
 .LP
-Portable Network Graphics (PNG) Specification Version 1.0 (October 1, 1996):
-Thomas Boutell and others.
+Portable Network Graphics (PNG) Specification Version 1.1 (31 December 1998):
+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
--- a/png.c
+++ b/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
@ -108,7 +108,13 @@ 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),
                  "Potential overflow in png_zalloc()");
@ -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:
 *
--- a/png.h
+++ b/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
@ -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 */
-#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 */
+#  define PNG_ARM_NEON 0
 #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 */
--- a/pngconf.h
+++ b/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) ||\
-      (defined(__BORLANDC__) && __BORLANDC__ < 0x500)
-   /* older Borland and MSC
-    * compilers used '__export' and required this to be after
-    * 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 */
--- a/pngdebug.h
+++ b/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
--- a/pngerror.c
+++ b/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.
--- a/pngget.c
+++ b/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.
--- a/pnginfo.h
+++ b/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
- * that the application can find out the characteristics of the image.
- * If you are reading the file, this structure will tell you what is
- * 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
- * call png_write_info().
+#ifndef PNGPRIV_H
+#  error This file must not be included by applications; please include <png.h>
+#endif
+
+/* INTERNAL, PRIVATE definition of a PNG.
 *
- * The names chosen should be very close to the PNG specification, so
- * consult that document for information about the meaning of each field.
+ * png_info is a modifiable description of a PNG datastream.  The fields inside
+ * 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
- * the values in the png_info_struct, which meant that the contents and
- * order of the values had to remain fixed.  With libpng 0.95 and later,
- * however, there are now functions that abstract the contents of
- * 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.
+ * Some functions in libpng do directly access members of png_info.  However,
+ * this should be avoided.  png_struct objects contain members which hold
+ * caches, sometimes optimised, of the values from png_info objects, and
+ * png_info is not passed to the functions which read and write image data.
 */
 #ifndef PNGINFO_H
 #define PNGINFO_H
--- a/pngmem.c
+++ b/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.
--- a/pngpread.c
+++ b/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)
--- a/pngpriv.h
+++ b/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
+#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"
-#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 \
-      "-I (include path) error: see the notes in pngpriv.h"
-   /* This means that when pnglibconf.h was built the copy of zlib.h that it
-    * used is not the same as the one being used here.  Because the build of
-    * libpng makes decisions to use inflateInit2 and inflateReset2 based on the
-    * zlib version number and because this affects handling of certain broken
-    * PNG files the -I directives must match.
+#  error The include path of <zlib.h> is incorrect
+   /* When pnglibconf.h was built, the copy of zlib.h that it used was not the
+    * same as the one being used here.  Considering how libpng makes decisions
+    * to use the zlib API based on the zlib version number, the -I options must
+    * match.
    *
-    * The most likely explanation is that you passed a -I in CFLAGS. This will
-    * not work; all the preprocessor directives and in particular all the -I
-    * directives must be in CPPFLAGS.
+    * A possible cause of this mismatch is that you passed an -I option in
+    * CFLAGS, which is unlikely to work.  All the preprocessor options, and all
+    * 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 */
--- a/pngread.c
+++ b/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
--- a/pngrio.c
+++ b/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");
--- a/pngrtran.c
+++ b/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. */
--- a/pngrutil.c
+++ b/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)
--- a/pngset.c
+++ b/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
-       * the input values by 2 and use png_fixed:
-       */
-      png_fixed(png_ptr, white_x / 2, "png_set_mDCV(white(x))"),
-      png_fixed(png_ptr, white_y / 2, "png_set_mDCV(white(y))"),
-      png_fixed(png_ptr, red_x / 2, "png_set_mDCV(red(x))"),
-      png_fixed(png_ptr, red_y / 2, "png_set_mDCV(red(y))"),
-      png_fixed(png_ptr, green_x / 2, "png_set_mDCV(green(x))"),
-      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(png_ptr, white_x, "png_set_mDCV(white(x))"),
+      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, red_y, "png_set_mDCV(red(y))"),
+      png_fixed(png_ptr, green_x, "png_set_mDCV(green(x))"),
+      png_fixed(png_ptr, green_y, "png_set_mDCV(green(y))"),
+      png_fixed(png_ptr, blue_x, "png_set_mDCV(blue(x))"),
+      png_fixed(png_ptr, blue_y, "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)"));
 }
--- a/pngstruct.h
+++ b/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.
- * The only people who need to care about what is inside of this are the
- * people who will be modifying the library for their own special needs.
- * It should NOT be accessed directly by an application.
- */
+#ifndef PNGPRIV_H
+#  error This file must not be included by applications; please include <png.h>
+#endif

 #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

--- a/pngtest.c
+++ b/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 png_FILE_p fpout;  /* "static" prevents setjmp corruption */
+   static FILE *fpin;
+   static FILE *fpout;  /* "static" prevents setjmp corruption */
   pngtest_error_parameters error_parameters;
   png_structp read_ptr;
   png_infop read_info_ptr, end_info_ptr;
--- a/pngwio.c
+++ b/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
--- a/pngwrite.c
+++ b/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)
--- a/pngwutil.c
+++ b/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.
--- a/powerpc/filter_vsx_intrinsics.c
+++ b/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)
--- a/powerpc/powerpc_init.c
+++ b/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 */

--- a/projects/visualc71/libpng.vcproj
+++ b/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"
--- a/riscv/.editorconfig
+++ b/riscv/.editorconfig
@ -0,0 +1,8 @@
+# https://editorconfig.org
+
+root = false
+
+# FIXME
+[*.[ch]]
+max_doc_length = unset
+max_line_length = unset
--- a/riscv/filter_rvv_intrinsics.c
+++ b/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 */
--- a/riscv/riscv_init.c
+++ b/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 */
--- a/scripts/cmake/AUTHORS.md
+++ b/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
--- a/scripts/cmake/PNGCheckLibconf.cmake
+++ b/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: ${_CHK_DFA_XTRA}")
+    endif()
+  endif()
+endfunction()
--- a/scripts/cmake/PNGGenConfig.cmake
+++ b/scripts/cmake/PNGGenConfig.cmake
@ -18,21 +18,21 @@ function(generate_chk)
  set(options)
  set(oneValueArgs INPUT OUTPUT)
  set(multiValueArgs DEPENDS)
-  cmake_parse_arguments(_GC "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
-  if(NOT _GC_INPUT)
+  cmake_parse_arguments(_GENCHK "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
+  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}"
-                             "-DOUTPUT=${_GC_OUTPUT}"
+                             "-DINPUT=${_GENCHK_INPUT}"
+                             "-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}" ${ARGN})
-  if(NOT _GO_INPUT)
+  cmake_parse_arguments(_GENOUT "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
+  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}"
-                             "-DOUTPUT=${_GO_OUTPUT}"
+                             "-DINPUT=${_GENOUT_INPUT}"
+                             "-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}" ${ARGN})
-  if(NOT _GSO_OUTPUT)
+  cmake_parse_arguments(_GENSRC "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
+  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}" ${ARGN})
-  if(NOT _GCO_INPUT)
+  cmake_parse_arguments(_GENCPY "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
+  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}"
-                     DEPENDS "${source}" ${_GCO_DEPENDS})
+                             -E copy "${_GENCPY_INPUT}" "${_GENCPY_OUTPUT}"
+                     DEPENDS "${_GENCPY_INPUT}" ${_GENCPY_DEPENDS})
 endfunction()
--- a/scripts/cmake/genout.cmake.in
+++ b/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@)
--- a/scripts/cmake/gensrc.cmake.in
+++ b/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")
-  # Generate scripts/pnglibconf.c
+if(OUTPUT MATCHES "(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")
-  # Generate pnglibconf.c
+elseif(OUTPUT MATCHES "(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")
-  # Generate pnglibconf.h
+elseif(OUTPUT MATCHES "(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 "${BINDIR}/pnglibconf.out"
-                                                       "${BINDIR}/${OUTPUT}"
+    execute_process(COMMAND "${CMAKE_COMMAND}" -E copy "pnglibconf.out"
+                                                       "${OUTPUT}"
+                    WORKING_DIRECTORY "${BINDIR}"
                    RESULT_VARIABLE COPY_FAIL)
    if(COPY_FAIL)
      message(FATAL_ERROR "Failed to create pnglibconf.h")
    endif()
  endif()

-elseif(OUTPUT STREQUAL "pngprefix.h")
-  # Generate pngprefix.h
+elseif(OUTPUT MATCHES "(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")
--- a/scripts/libpng-config-head.in
+++ b/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=""
--- a/scripts/libpng.pc.in
+++ b/scripts/libpng.pc.in
@ -5,6 +5,6 @@ includedir=@includedir@/libpng16

 Name: libpng
 Description: Loads and saves PNG files
-Version: 1.6.47
+Version: 1.6.51.git
 Libs: -L${libdir} -lpng16
 Cflags: -I${includedir}
--- a/scripts/makefile.c89
+++ b/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 \
--- a/scripts/makefile.clang
+++ b/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 \
--- a/scripts/makefile.darwin
+++ b/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 \
--- a/scripts/makefile.gcc
+++ b/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 \
--- a/scripts/makefile.linux
+++ b/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 \
--- a/scripts/makefile.msys
+++ b/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 \
--- a/scripts/makefile.std
+++ b/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
--- a/scripts/pnglibconf.h.prebuilt
+++ b/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 */
--- a/8
+++ b/8
@ -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:
Author	SHA1	Message	Date
Cosmin Truta	7cecdcae07	Harden a vestigial check against overflow inside `png_zalloc` Reported-by: Sergio Atienza Pastor, MTP Métodos y Tecnología	2025-07-03 22:42:11 +03:00
Cosmin Truta	cf59edd364	Bump version to 1.6.51.git	2025-07-02 20:24:24 +03:00
Cosmin Truta	2b978915d8	Release libpng version 1.6.50	2025-07-01 23:50:00 +03:00
Cosmin Truta	254a64ec30	doc: Update the man pages to the final PNG-3 specification Also make editorial changes regarding the previous PNG specifications.	2025-07-01 22:57:36 +03:00
Cosmin Truta	9eb25bd899	chore: Rerun `./autogen.sh --maintainer`	2025-06-30 23:46:32 +03:00
Cosmin Truta	8087a21d0a	build: Fix the CMake file for cross-platform builds that require `libm` Detect the availability of `libm` on the target platform. Previously, `libm` was detected on the host platform only. Also introduce the variable `PNG_LINK_LIBRARIES`. Stop using `M_LIBRARY`, which was not namespace-clean.	2025-06-30 22:27:17 +03:00
John Bowler	2e5f296bfa	fix: Prevent unknown chunks from causing out-of-place IEND errors PNG_AFTER_IDAT was not set by the IDAT read code if unknown chunk handling was turned on. This was hidden in the current tests by checks within the text handling chunks. (For example, pngtest.png has a zTXt chunk after IDAT.) This change modifies both the sequential and the progressive reader to reliably set PNG_AFTER_IDAT when the first non-IDAT chunk is seen and before that chunk is processed. The change is minimalist; PNG_HAVE_CHUNK_AFTER_IDAT can probably be removed and replaced with PNG_AFTER_IDAT. Making the latter change is something to be considered in libpng2. Co-authored-by: Cosmin Truta <ctruta@gmail.com> Signed-off-by: John Bowler <jbowler@acm.org> Signed-off-by: Cosmin Truta <ctruta@gmail.com>	2025-06-30 16:27:22 +03:00
Filip Wasil	4266c75f40	riscv: Remove unused argument Signed-off-by: Cosmin Truta <ctruta@gmail.com>	2025-06-28 16:19:11 +03:00
Filip Wasil	f451a4de09	riscv: Simplify the runtime check to always be present Signed-off-by: Cosmin Truta <ctruta@gmail.com>	2025-06-28 16:19:11 +03:00
Filip Wasil	6aa47debba	riscv: Do not overwrite `-march` when testing against SIMD availability Signed-off-by: Cosmin Truta <ctruta@gmail.com>	2025-06-28 16:19:11 +03:00
Filip Wasil	3391bb98e3	riscv: Use C intrinsics Signed-off-by: Cosmin Truta <ctruta@gmail.com>	2025-06-28 16:19:11 +03:00
Filip Wasil	21895b05ab	riscv: Clearly separate the build flow for autotools and cmake Signed-off-by: Cosmin Truta <ctruta@gmail.com>	2025-06-18 14:43:36 +03:00
Cosmin Truta	be81ebe1a4	chore: Rerun `./autogen.sh --maintainer`	2025-06-17 11:41:32 +03:00
Filip Wasil	edf46621f3	riscv: Improve the RVV availability check In some cases, the vector extension is not supported, although the compiler allows the "v" flag in `-march` and includes `<riscv_vector>` without raising an error. Signed-off-by: Cosmin Truta <ctruta@gmail.com>	2025-06-17 11:40:57 +03:00
Cosmin Truta	5dc5937b30	chore: Update .gitignore This is a cherry-pick of commit df3b9173277aae60b08a216dc23484f6ec171ef5 from branch 'libpng18'.	2025-06-14 18:35:46 +03:00
Cosmin Truta	7084241c75	Bump version to 1.6.50.git	2025-06-14 17:13:02 +03:00
Cosmin Truta	640204280f	Release libpng version 1.6.49	2025-06-12 20:05:46 +03:00
Cosmin Truta	740366c32b	doc: Update the png.5 man page to the latest PNG-3 draft	2025-06-12 19:58:06 +03:00
Cosmin Truta	5d53dfd20c	chore: Rerun `./autogen.sh --maintainer`	2025-06-12 18:46:04 +03:00
Filip Wasil	5b62726ced	riscv: Fix autodetection of RVV support Signed-off-by: Cosmin Truta <ctruta@gmail.com>	2025-06-12 18:44:02 +03:00
Cosmin Truta	a5830bfcb1	build: Fix the detection of the math library in the CMake file This is a fix of commit 5631b9b952e6940c67d4b48c00882e99229aa31b "build: Implement various improvements to the CMake file"	2025-06-11 21:38:01 +03:00
Cosmin Truta	3bca02e274	examples: Refactor and reformat using clang-format Add contrib/examples/.clang-format, tailored to fit the existing code as closely as possible. The end goal is to set up automatic formatting for the entire libpng source tree. We're doing this experiment in this subdirectory, for now. Also make refactoring changes, as follows: * Rewrite the preprocessor checks `#if PNG_FOO_SUPPORTED` to stop compilation immediately, with a descriptive `#error` about what needs to be supported. * Rewrite and reflow comments, add braces and brackets, and make other minor modifications that are suited for the clang-format'ed code.	2025-06-01 22:40:38 +03:00
Sanjay Jangid	197bbfe0d5	examples: Fix file descriptor leak in iccfrompng.c by closing input file Reviewed-by: Cosmin Truta <ctruta@gmail.com> Signed-off-by: Cosmin Truta <ctruta@gmail.com>	2025-05-31 17:06:28 +03:00
Cosmin Truta	0cc6436ef5	build: Repair and reduce the CMake build dependency graph A funny thing happened while refactoring the function argument parsing in the `PNGGenConfig` module: the processing of dependencies inside the CMake function `generate_copy` got fixed, thanks to an inadvertent typo correction! Going down the rabbit hole, we uncovered two issues: 1. A typo in `scripts/cmake/PNGGenConfig.cmake` caused a dependency declaration to disappear, disrupting the graph. Fortunately, this disruption was being mitigated by an additional set of (redundant) symbolic target declarations that kept the CMake build going. 2. The exact string matching inside `scripts/cmake/gensrc.cmake.in` imposed an artificial limitation, disallowing the use of absolute file paths. The typo correction in (1), and the use of regex matching instead of exact string matching in (2), allowed us to use absolute file paths in the main CMake file, consistently, thus allowing CMake to recognize them as uniquely-identifiable nodes in the dependency graph. There should be no further need to have extra symbolic targets for proper node identification. In the end, we shaved off the redundant symbolic target declarations, retaining only `png_genfiles` and `png_genprebuilt`.	2025-05-29 22:55:00 +03:00
Cosmin Truta	f04c457a51	build: Remove the PNG_DEBUG option from CMake files and project files Counter-intuitively, defining the PNG_DEBUG macro as 1 (i.e. setting the debug verbosity level to 1) does not cause any of the existing debug traces to show up. This setting would have worked if we had trace statements like `png_debug(0, message)`, but we don't have any. Debug traces do show up for verbosity levels from 2 to 5. The libpng manual describes in detail how they are meant to be used. According to the history of the CMake file, as well as the history of other project files, PNG_DEBUG was never set to a numeric value larger than 1. In other words, these debug settings inside these build files never produced any output in any (unmodified) libpng version. (As for the configure build, PNG_DEBUG has no special treatment there.) Considering the plethora of alternative methods to pass C preprocessor options through our build files, scripts and projects onto libpng, we'd rather discontinue PNG_DEBUG as a dedicated build option.	2025-05-29 19:47:03 +03:00
Cosmin Truta	5631b9b952	build: Implement various improvements to the CMake file Allow the CMake build to work properly, even if file paths (in the source directory, in the build directory, or in the install directory) might contain whitespace characters. Improve the check for compilers that might use MSVC Runtime library headers on Windows. We use POSIX-ish ("deprecated") functions, even on Windows, and we want no spurious warnings. Tidy up the CMake file: rearrange declarations, rewrite comments, etc.	2025-05-29 18:28:16 +03:00
Joost Nieuwenhuijse	dc71f481ff	build: Fix apple-non-apple cross building When cross compiling for an apple platform on a non-apple platform (or the reverse), `if(APPLE)` in line 32 should refer to the target platform. Without importing the `APPLE` variable, it refers to the host platform. Reviewed-by: John Bowler <jbowler@acm.org> Signed-off-by: Cosmin Truta <ctruta@gmail.com>	2025-05-28 17:24:21 +03:00
Cosmin Truta	e2c1579816	ci: Add action-editorconfig-checker to the GitHub Action for linting The editorconfig-checker program is not installed by default in the OS used by GitHub Actions. Fortunately, the editorconfig-checker authors have kindly provided the action-editorconfig-checker repository, which we are now using.	2025-05-28 11:02:47 +03:00
Cosmin Truta	cff8620272	chore: Add riscv/.editorconfig and pacify editorconfig-checker Also tidy up the new RISC-V code to comply with our coding style, and rearrange comments inside png.h to improve readability within the configured editing limits.	2025-05-27 11:28:56 +03:00
Cosmin Truta	5be32eb35c	chore: Rerun `./autogen.sh --maintainer`	2025-05-26 22:37:06 +03:00
Filip Wasil	611bf1016c	riscv: autotools update	2025-05-19 15:58:44 +02:00
Filip Wasil	0e37c0b477	riscv: Fix more comments Signed-off-by: Cosmin Truta <ctruta@gmail.com>	2025-05-14 22:35:47 +03:00
Filip Wasil	7108843467	riscv: Fix the run-time checking of the RVV availability Signed-off-by: Cosmin Truta <ctruta@gmail.com>	2025-05-14 10:24:58 +03:00
Filip Wasil	2b0eb78656	riscv: Fix autotools definitions and comments Signed-off-by: Cosmin Truta <ctruta@gmail.com>	2025-05-14 10:24:58 +03:00
Filip Wasil	ffb8e8b26f	Fix and improve the RISC-V Vector (RVV) implementation Changes include manually merged code from Manfred SCHLAEGL. Co-authored-by: Manfred SCHLAEGL <manfred.schlaegl@gmx.at> Signed-off-by: Cosmin Truta <ctruta@gmail.com>	2025-05-01 17:44:00 +03:00
Dragoș Tiselice	cc5ee6b213	Add optimized RISC-V Vector functions Largely based off of the ARM NEON implementation. Signed-off-by: Cosmin Truta <ctruta@gmail.com>	2025-05-01 17:44:00 +03:00
Cosmin Truta	b4800bae33	Bump version to 1.6.49.git	2025-05-01 14:50:23 +03:00
Cosmin Truta	ea12796820	Release libpng version 1.6.48	2025-04-30 16:51:46 +03:00
Cosmin Truta	643dbda7d6	doc: Update the png.5 man page to the latest PNG-3 draft specification Also update libpngpf.3 to explicitly state that the internal functions should not be used by applications.	2025-04-30 16:30:24 +03:00
Cosmin Truta	34e3f7a65b	Remove the config for Travis CI (and thank them for their support!) Signed-off-by: Cosmin Truta <ctruta@gmail.com>	2025-04-30 11:49:37 +03:00
Cosmin Truta	3e67531078	chore: Add a TODO note in .cmake-format.yaml; reformat CMakeLists.txt Apply some (but not all) of the suggestions made by the cmake-format program. Meanwhile, the cmake-lint program is (still) happy.	2025-04-29 17:30:30 +03:00
Cosmin Truta	23bdc7a6c4	build: Add the CMake build option `PNG_LIBCONF_HEADER` Running the pnglibconf scripts (script/.awk) is not always possible. An AWK interpreter is not always guaranteed to be available; and even if it is, there are limitations when making cross-platform libpng builds, especially when the differences between the host platform and the target platform are significant. For example: Building for the Windows (MinGW) target on a Unix development host; * Building for the iOS target on a macOS development host; * Building for the Android target on any development host. In such scenarios, a preconfigured (i.e. prebuilt) pnglibconf.h file, either taken from the libpng source tree or provided by the user who wants to make a custom libpng build, becomes a necessity. In this commit we introduce the build option `PNG_LIBCONF_HEADER` in order to address this specific use case. We also specify a version range (3.14...4.0) for the minimum required CMake program, to future-proof the CMake build for just a little bit longer. Signed-off-by: Cosmin Truta <ctruta@gmail.com>	2025-04-28 20:44:53 +03:00
Cosmin Truta	69a3e5bfd1	chore: Clean up the error directives Make the error directives uniformly consistent with one another. Remove surrounding quotes and trailing punctuation, and rephrase some of the error messages and some of their associated comments for either brevity or clarity.	2025-04-25 16:19:30 +03:00
Cosmin Truta	c90491724e	Discourage the inclusion of private headers outside libpng Add checks inside the private png*.h header files, in order to reduce unintentional occurences of application backdoors. Such backdoors might occur, for example, when we make changes to the internal data structures that might somehow "leak" from the libpng code into the user code. The applications that use the libpng API must pretend not to know that these headers exist at all. Co-authored-by: John Bowler <jbowler@acm.org> Signed-off-by: John Bowler <jbowler@acm.org> Signed-off-by: Cosmin Truta <ctruta@gmail.com>	2025-04-25 15:35:11 +03:00
John Bowler	98448e372d	Remove unused function from write-only configurations `png_icc_profile_error` is no longer used when writing iCCP chunks, therefore it can be compiled out when the reading is disabled. This change includes two `minconfig` files to test read-only and write-only "full" configurations, to supplement the existing tests for "minimal" configurations. Signed-off-by: John Bowler <jbowler@acm.org> Signed-off-by: Cosmin Truta <ctruta@gmail.com>	2025-04-22 19:35:01 +03:00
John Bowler	f2b0f5fe1c	fix(mDCv): Correct the floating-point setter `png_set_mDCv` In the floating-point API function `png_set_mDCv` we incorrectly divided by two the chromaticity values before passing them on to `png_set_mDCv_fixed`. Reported-by: Mohit Bakshi <mohitbakshi2205@gmail.com> Signed-off-by: John Bowler <jbowler@acm.org> Signed-off-by: Cosmin Truta <ctruta@gmail.com>	2025-04-22 18:08:39 +03:00
Chris Blume	7101a5569f	Correct mistake in example.c	2025-04-22 18:04:46 +03:00
Cosmin Truta	e046c0dc3b	Revert "Recover from errors in ancillary chunks" This reverts commit 34005e3d3d373c0c36898cc55eae48a79c8238a1. Although I agreed with Lucas Chollet initially, I finally understood the objection brought forth by John Bowler: "[...] it's not an ancillary chunk type if it's not a chunk type in the first place." I feel that more deliberation is needed on what a robust PNG decoder should do when it stumbles upon a chunk type that fails to meet its basic requirements. A clarifying recommendation for decoders may or may not need to be stipulated in the PNG specification as well. Signed-off-by: Cosmin Truta <ctruta@gmail.com>	2025-04-22 16:39:01 +03:00
Lucas CHOLLET	34005e3d3d	Recover from errors in ancillary chunks As per the third edition of the spec, decoders should recover from errors in ancillary chunks. In section 13.1 Error handling [1]: > Anomalous situations other than syntax errors shall be treated as > follows: > 1. Encountering an unknown ancillary chunk is never an error. The > chunk can simply be ignored. More specifically, in this commit, if a chunk that is detected as ancillary, does not pass the `check_chunk_name()` function, only a _benign_ is issued, instead of an error. This allows libpng to fully decode images like [2] and [3]. It has been tested by passing them to both pngtest and Gnome's image viewer. Note that invalid-unknown-ancillary-after-IDAT.png could already be displayed but not fully decoded. [1] https://w3c.github.io/png/#13Decoders.Errors [2] https://github.com/web-platform-tests/wpt/blob/master/png/errors/support/invalid-unknown-ancillary.png [3] https://github.com/web-platform-tests/wpt/blob/master/png/errors/support/invalid-unknown-ancillary-after-IDAT.png	2025-03-04 15:13:19 -07:00
Cosmin Truta	44f97f08d7	[libpng18] chore: Clean up the `FILE ` formulations in code and in documentation We should use `FILE ` instead of `FILE` or `(FILE)`, consistently, as we should for all other pointer types. Moreover, when we refer to standard stdio file objects in comments and in documentation, we should use the term "FILE objects" consistently. Lastly, we clarify in a comment in example.c that `PNG_STDIO_SUPPORTED` is true only when the stdio support is both available in the system and accessible in the user's libpng build. This is a cherry-pick of commit c63c5463903014c904b540216c2784023fb8c1c8 from branch 'libpng18'. Reviewed-by: John Bowler <jbowler@acm.org> Signed-off-by: Cosmin Truta <ctruta@gmail.com>	2025-02-26 19:46:08 +02:00
Cosmin Truta	044536de92	[libpng18] chore: Clean up remnants of the long-discontinued Win16 support Remove #ifdef sections and other workarounds for old Windows compilers that lacked proper support for Win32, including, especially, support for the Win32 stdio API. This is a cherry-pick of commit e936211760ddf0ed4a4711ea897b59395dfd206e from branch 'libpng18'. Reviewed-by: John Bowler <jbowler@acm.org> Signed-off-by: Cosmin Truta <ctruta@gmail.com>	2025-02-26 19:42:28 +02:00
Cosmin Truta	738f5e743c	ci: Add more checks to ci_verify_version.sh; refactor In addition to png.h, configure.ac and CMakeLists.txt, the script ci_verify_version.sh is now able to verify libpng-config-head.in also. For the benefit of readability, the old script ci_shellify.sh has been split into smaller, independent scriptlets: libexec/ci_shellify_*.sh. The linting script ci_lint.sh has been updated as needed.	2025-02-20 11:59:16 +02:00
Cosmin Truta	f20e66aa93	chore: Apply some of the missed updates to the copyright year	2025-02-19 13:15:14 +02:00
Cosmin Truta	5d09501462	Bump version to 1.6.48.git	2025-02-19 13:07:40 +02:00