[libpng16] Imported from libpng-1.6.24beta03.tar

[libpng16] Update CHANGES and ANNOUNCE
pngcp bug fixes
2025-07-10 18:04:09 +02:00 · 2016-07-04 09:55:12 -05:00 · 2016-07-03 18:10:21 -05:00 · 2016-07-03 13:49:36 -07:00 · 2016-07-03 10:28:54 -05:00 · 2016-07-02 21:17:56 -05:00
53 changed files with 3495 additions and 402 deletions
--- a/133
+++ b/133
@@ -1,88 +1,83 @@
-Libpng 1.6.22 - May 26, 2016
+Libpng 1.6.24beta03 - July 4, 2016

-This is a public release of libpng, intended for use in production codes.
+This is not intended to be a public release.  It will be replaced
+within a few weeks by a public version or by another test version.

 Files available for download:

 Source files with LF line endings (for Unix/Linux) and with a
 "configure" script

-   libpng-1.6.22.tar.xz (LZMA-compressed, recommended)
-   libpng-1.6.22.tar.gz
+   1.6.24beta03.tar.xz (LZMA-compressed, recommended)
+   1.6.24beta03.tar.gz

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

-   lpng1622.7z  (LZMA-compressed, recommended)
-   lpng1622.zip
+   lp1624b03.7z  (LZMA-compressed, recommended)
+   lp1624b03.zip

 Other information:

-   libpng-1.6.22-README.txt
-   libpng-1.6.22-LICENSE.txt
-   libpng-1.6.22-*.asc (armored detached GPG signatures)
+   1.6.24beta03-README.txt
+   1.6.24beta03-LICENSE.txt
+   libpng-1.6.24beta03-*.asc (armored detached GPG signatures)

-Changes since the last public release (1.6.21):
-  Changed PNG_USE_MKSTEMP to __COVERITY__ to select alternate
-    "tmpfile()" implementation in contrib/libtests/pngstest.c
-  Fixed NO_STDIO build of pngunknown.c to skip calling png_init_io()
-    if there is no stdio.h support.
-  Added a png_image_write_to_memory() API and a number of assist macros
-    to allow an application that uses the simplified API write to bypass
-    stdio and write directly to memory.
-  Added some warnings (png.h) and some check code to detect *possible*
-    overflow in the ROW_STRIDE and simplified image SIZE macros.  This
-    disallows image width/height/format that *might* overflow.  This is
-    a quiet API change that limits in-memory image size (uncompressed) to
-    less than 4GByte and image row size (stride) to less than 2GByte.
-  Revised workaround for false-positive Coverity issue in pngvalid.c.
-  Only use exit(77) in configure builds.
-  Updated CMakeLists.txt, added supporting scripts/gen*.cmake.in
-    and test.cmake.in (Roger Leigh).
-  Relaxed limit checks on gamma values in pngrtran.c. As suggested in
-    the comments gamma values outside the range currently permitted
-    by png_set_alpha_mode are useful for HDR data encoding.  These values
-    are already permitted by png_set_gamma so it is reasonable caution to
-    extend the png_set_alpha_mode range as HDR imaging systems are starting
-    to emerge.
-  Added a common-law trademark notice and export control information
-    to the LICENSE file, png.h, and the man page.
-  Restored "& 0xff" in png_save_uint_16() and png_save_uint_32() that
-    were accidentally removed from libpng-1.6.17. 
-  Changed PNG_INFO_cHNK and PNG_FREE_cHNK from 0xnnnn to 0xnnnnU in png.h
-    (Robert C. Seacord).
-  Removed dubious "#if INT_MAX" test from png.h that was added to
-    libpng-1.6.19 (John Bowler).
-  Add ${INCLUDES} in scripts/genout.cmake.in (Bug report by Nixon Kwok).
-  Updated LICENSE to say files in the contrib directory are not
-    necessarily under the libpng license, and that some makefiles have
-    other copyright owners.
-  Added INTEL-SSE2 support (Mike Klein and Matt Sarett, Google, Inc.).
-  Made contrib/libtests/timepng more robust.  The code no longer gives
-    up/fails on invalid PNG data, it just skips it (with error messages).
-    The code no longer fails on PNG files with data beyond IEND.  Options
-    exist to use png_read_png (reading the whole image, not by row) and, in
-    that case, to apply any of the supported transforms.  This makes for
-    more realistic testing; the decoded data actually gets used in a
-    meaningful fashion (John Bowler).
-  Fixed some misleading indentation (Krishnaraj Bhat).
-  Force GCC compilation to C89 if needed (Dagobert Michelsen).
-  SSE filter speed improvements for bpp=3:
-    memcpy-free implementations of load3() / store3().
-    call load3() only when needed at the end of a scanline.
-  Added PNG_FAST_FILTERS macro (defined as
-    PNG_FILTER_NONE|PNG_FILTER_SUB|PNG_FILTER_UP).
-  Various fixes for contrib/libtests/timepng.c
-  Fixed typo (missing underscore) in #define PNG_READ_16_TO_8_SUPPORTED
-    (Bug report by Y.Ohashik).
-  Quieted two Coverity issues in contrib/libtests/timepng.c.
-  Fixed issues with scripts/genout.cmake.in (David Capello, Nixon Kwok):
-    Added support to use multiple directories in ZLIBINCDIR variable,
-    Fixed CMAKE_C_FLAGS with multiple values when genout is compiled on MSVC,
-    Fixed pnglibconf.c compilation on OS X including the sysroot path.
-  Check for CLOCK_PROCESS_CPUTIME_ID when building /contrib/libtests/timepng.
-  Check for the presence of clock_gettime() in configure.ac and Makefile.am.
+Changes since the last public release (1.6.23):

+Version 1.6.24beta01 [June 11, 2016]
+  Avoid potential overflow of the PNG_IMAGE_SIZE macro.  This macro
+    is not used within libpng, but is used in some of the examples.
+
+Version 1.6.24beta02 [June 23, 2016]
+  Correct filter heuristic overflow handling. This was broken when the
+    write filter code was moved out-of-line; if there is a single filter and
+    the heuristic sum overflows the calculation of the filtered line is not
+    completed.  In versions prior to 1.6 the code was duplicated in-line
+    and the check not performed, so the filter operation completed; however,
+    in the multi-filter case where the sum is performed the 'none' filter would
+    be selected if all the sums overflowed, even if it wasn't in the filter
+    list.  The fix to the first problem is simply to provide PNG_SIZE_MAX as
+    the current lmins sum value; this means the sum can never exceed it and
+    overflows silently.  A reasonable compiler that does choose to inline
+    the code will simply eliminate the sum check.
+  The fix to the second problem is to use high precision arithmetic (this is
+    implemented in 1.7), however a simple safe fix here is to chose the lowest
+    numbered filter in the list from png_set_filter (this only works if the
+    first problem is also fixed) (John Bowler).
+  Use a more efficient absolute value calculation on SSE2 (Matthieu Darbois).
+  Fixed the case where PNG_IMAGE_BUFFER_SIZE can overflow in the application
+    as a result of the application using an increased 'row_stride'; previously
+    png_image_finish_read only checked for overflow on the base calculation of
+    components.  (I.e. it checked for overflow of a 32-bit number on the total
+    number of pixel components in the output format, not the possibly padded row
+    length and not the number of bytes, which for linear formats is twice the
+    number of components.)
+  MSVC does not like '-(unsigned)', so replaced it with 0U-(unsigned)
+  MSVC does not like (uInt) = -(unsigned) (i.e. as an initializer), unless
+    the conversion is explicitly invoked by a cast.
+  Put the SKIP definition in the correct place. It needs to come after the
+    png.h include (see all the other .c files in contrib/libtests) because it
+    depends on PNG_LIBPNG_VER.
+  Removed the three compile warning options from the individual project
+    files into the zlib.props globals.  It increases the warning level from 4
+    to All and adds a list of the warnings that need to be turned off.  This is
+    semi-documentary; the intent is to tell libpng users which warnings have
+    been examined and judged non-fixable at present.  The warning about
+    structure padding is fixable, but it would be a signficant change (moving
+    structure members around).
+
+Version 1.6.24beta03 [July 4, 2016]
+  Optimized absolute value calculation in filter selection, similar to
+    code in the PAETH decoder in pngrutil.c. Build with PNG_USE_ABS to
+    use this.
+  Added pngcp to the build together with a pngcp.dfa configuration test.
+  Added high resolution timing to pngcp.
+  Added "Common linking failures" section to INSTALL.
+  Relocated misplaced #endif in png.c sRGB profile checking.
+  Fixed two Coverity issues in pngcp.c.
+
+Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
 https://lists.sourceforge.net/lists/listinfo/png-mng-implement
 to subscribe)
--- a/75
+++ b/75
@@ -5573,6 +5573,81 @@ Version 1.6.22rc03 [May 17, 2016]
 Version 1.6.22 [May 26, 2016]
  No changes.

+Version 1.6.23beta01 [May 29, 2016]
+  Stop a potential memory leak in png_set_tRNS() (Bug report by Ted Ying).
+  Fixed the progressive reader to handle empty first IDAT chunk properly
+    (patch by Timothy Nikkel).  This bug was introduced in libpng-1.6.0 and
+    only affected the libpng16 branch.
+  Added tests in pngvalid.c to check zero-length IDAT chunks in various
+    positions.  Fixed the sequential reader to handle these more robustly
+    (John Bowler).
+
+Version 1.6.23rc01 [June 2, 2016]
+  Corrected progressive read input buffer in pngvalid.c. The previous version
+    the code invariably passed just one byte at a time to libpng.  The intent
+    was to pass a random number of bytes in the range 0..511.
+  Moved sse2 prototype from pngpriv.h to contrib/intel/intel_sse.patch.
+  Added missing ")" in pngerror.c (Matt Sarrett).
+
+Version 1.6.23rc02 [June 4, 2016]
+  Fixed undefined behavior in png_push_save_buffer(). Do not call
+    memcpy() with a null source, even if count is zero (Leon Scroggins III).
+
+Version 1.6.23 [June 9, 2016]
+  Fixed bad link to RFC2083 in png.5 (Nikola Forro).
+
+Version 1.6.24beta01 [June 11, 2016]
+  Avoid potential overflow of the PNG_IMAGE_SIZE macro.  This macro
+    is not used within libpng, but is used in some of the examples.
+
+Version 1.6.24beta02 [June 23, 2016]
+  Correct filter heuristic overflow handling. This was broken when the
+    write filter code was moved out-of-line; if there is a single filter and
+    the heuristic sum overflows the calculation of the filtered line is not
+    completed.  In versions prior to 1.6 the code was duplicated in-line
+    and the check not performed, so the filter operation completed; however,
+    in the multi-filter case where the sum is performed the 'none' filter would
+    be selected if all the sums overflowed, even if it wasn't in the filter
+    list.  The fix to the first problem is simply to provide PNG_SIZE_MAX as
+    the current lmins sum value; this means the sum can never exceed it and
+    overflows silently.  A reasonable compiler that does choose to inline
+    the code will simply eliminate the sum check.
+  The fix to the second problem is to use high precision arithmetic (this is
+    implemented in 1.7), however a simple safe fix here is to chose the lowest
+    numbered filter in the list from png_set_filter (this only works if the
+    first problem is also fixed) (John Bowler).
+  Use a more efficient absolute value calculation on SSE2 (Matthieu Darbois).
+  Fixed the case where PNG_IMAGE_BUFFER_SIZE can overflow in the application
+    as a result of the application using an increased 'row_stride'; previously
+    png_image_finish_read only checked for overflow on the base calculation of
+    components.  (I.e. it checked for overflow of a 32-bit number on the total
+    number of pixel components in the output format, not the possibly padded row
+    length and not the number of bytes, which for linear formats is twice the
+    number of components.)
+  MSVC does not like '-(unsigned)', so replaced it with 0U-(unsigned)
+  MSVC does not like (uInt) = -(unsigned) (i.e. as an initializer), unless
+    the conversion is explicitly invoked by a cast.
+  Put the SKIP definition in the correct place. It needs to come after the
+    png.h include (see all the other .c files in contrib/libtests) because it
+    depends on PNG_LIBPNG_VER.
+  Removed the three compile warning options from the individual project
+    files into the zlib.props globals.  It increases the warning level from 4
+    to All and adds a list of the warnings that need to be turned off.  This is
+    semi-documentary; the intent is to tell libpng users which warnings have
+    been examined and judged non-fixable at present.  The warning about
+    structure padding is fixable, but it would be a signficant change (moving
+    structure members around).
+
+Version 1.6.24beta03 [July 4, 2016]
+  Optimized absolute value calculation in filter selection, similar to
+    code in the PAETH decoder in pngrutil.c. Build with PNG_USE_ABS to
+    use this.
+  Added pngcp to the build together with a pngcp.dfa configuration test.
+  Added high resolution timing to pngcp.
+  Added "Common linking failures" section to INSTALL.
+  Relocated misplaced #endif in png.c sRGB profile checking.
+  Fixed two Coverity issues in pngcp.c.
+
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
 https://lists.sourceforge.net/lists/listinfo/png-mng-implement
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -35,7 +35,7 @@ enable_testing()

 set(PNGLIB_MAJOR 1)
 set(PNGLIB_MINOR 6)
-set(PNGLIB_RELEASE 22)
+set(PNGLIB_RELEASE 24)
 set(PNGLIB_NAME libpng${PNGLIB_MAJOR}${PNGLIB_MINOR})
 set(PNGLIB_VERSION ${PNGLIB_MAJOR}.${PNGLIB_MINOR}.${PNGLIB_RELEASE})

@@ -696,7 +696,7 @@ endif(NOT WIN32 OR CYGWIN OR MINGW)
 # SET UP LINKS
 if(PNG_SHARED)
  set_target_properties(png PROPERTIES
-#   VERSION 16.${PNGLIB_RELEASE}.1.6.22
+#   VERSION 16.${PNGLIB_RELEASE}.1.6.24beta03
    VERSION 16.${PNGLIB_RELEASE}.0
    SOVERSION 16
    CLEAN_DIRECT_OUTPUT 1)
--- a/37
+++ b/37
@@ -18,7 +18,8 @@ VIII. Configuring libpng for 16-bit platforms
 XIII. Removing unwanted object code
 XIV. Changes to the build and configuration of libpng in libpng-1.5.x
  XV. Setjmp/longjmp issues
- XVI. Other sources of information about libpng
+ XVI. Common linking failures
+XVII. Other sources of information about libpng

 I. Simple installation

@@ -382,28 +383,20 @@ This requires setjmp/longjmp, so you must either build the library
 with PNG_SETJMP_SUPPORTED defined, or with PNG_SIMPLIFIED_READ_SUPPORTED
 and PNG_SIMPLIFIED_WRITE_SUPPORTED undefined.

-XVI. Other sources of information about libpng:
+XVI. Common linking failures
+
+If your application fails to find libpng or zlib entries while linking:
+
+  Be sure "-lz" appears after "-lpng" on your linking command.
+
+  Be sure you have built libpng, zlib, and your application for the
+  same platform (e.g., 32-bit or 64-bit).
+
+  If you are using the vstudio project, observe the WARNING in
+  project/vstudio/README.txt.
+
+XVII. Other sources of information about libpng:

 Further information can be found in the README and libpng-manual.txt
 files, in the individual makefiles, in png.h, and the manual pages
 libpng.3 and png.5.
-
-Using the ./configure script -- 16 December 2002.
-=================================================
-
-The ./configure script should work compatibly with what scripts/makefile.*
-did, however there are some options you might need to add to configure
-explicitly, which previously was done semi-automatically (if you didn't edit
-scripts/makefile.* yourself, that is)
-
-CFLAGS="-Wall -O -funroll-loops \
-malign-loops=2 -malign-functions=2" ./configure --prefix=/usr/include \
--with-pkgconfigdir=/usr/lib/pkgconfig --includedir=/usr/include
-
-You can alternatively specify --includedir=/usr/include, /usr/local/include,
-/usr/include/libpng16, or whatever.
-
-If you find that the configure script is out-of-date or is not supporting
-your platform properly, try running autogen.sh to regenerate "configure",
-"Makefile.in", and the other configuration files. Then try configure again.
-
--- a/4
+++ b/4
@@ -10,7 +10,7 @@ this sentence.

 This code is released under the libpng license.

-libpng versions 1.0.7, July 1, 2000 through 1.6.22, May 26, 2016 are
+libpng versions 1.0.7, July 1, 2000 through 1.6.24beta03, July 4, 2016 are
 Copyright (c) 2000-2002, 2004, 2006-2016 Glenn Randers-Pehrson, are
 derived from libpng-1.0.6, and are distributed according to the same
 disclaimer and license as libpng-1.0.6 with the following individuals
@@ -127,4 +127,4 @@ any encryption software.  See the EAR, paragraphs 734.3(b)(3) and

 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-May 26, 2016
+July 4, 2016
--- a/Makefile.am
+++ b/Makefile.am
@@ -18,7 +18,7 @@ check_PROGRAMS += timepng
 endif

 # Utilities - installed
-bin_PROGRAMS= pngfix png-fix-itxt
+bin_PROGRAMS= pngcp pngfix png-fix-itxt

 # This ensures that pnglibconf.h gets built at the start of 'make all' or
 # 'make check', but it does not add dependencies to the individual programs,
@@ -53,6 +53,9 @@ pngfix_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la

 png_fix_itxt_SOURCES = contrib/tools/png-fix-itxt.c

+pngcp_SOURCES = contrib/tools/pngcp.c
+pngcp_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+
 # Generally these are single line shell scripts to run a test with a particular
 # set of parameters:
 TESTS =\
@@ -230,6 +233,7 @@ contrib/libtests/timepng.o: pnglibconf.h

 contrib/tools/makesRGB.o: pnglibconf.h
 contrib/tools/pngfix.o: pnglibconf.h
+contrib/tools/pngcp.o: pnglibconf.h

 # We must use -DPNG_NO_USE_READ_MACROS here even when the library may actually
 # be built with PNG_USE_READ_MACROS; this prevents the read macros from
--- a/2
+++ b/2
@@ -1,4 +1,4 @@
-README for libpng version 1.6.22 - May 26, 2016 (shared library 16.0)
+README for libpng version 1.6.24beta03 - July 4, 2016 (shared library 16.0)
 See the note about version numbers near the top of png.h

 See INSTALL for instructions on how to install libpng.
--- a/configure.ac
+++ b/configure.ac
@@ -25,7 +25,7 @@ AC_PREREQ([2.68])

 dnl Version number stuff here:

-AC_INIT([libpng],[1.6.22],[png-mng-implement@lists.sourceforge.net])
+AC_INIT([libpng],[1.6.24beta03],[png-mng-implement@lists.sourceforge.net])
 AC_CONFIG_MACRO_DIR([scripts])

 # libpng does not follow GNU file name conventions (hence 'foreign')
@@ -46,10 +46,10 @@ dnl automake, so the following is not necessary (and is not defined anyway):
 dnl AM_PREREQ([1.11.2])
 dnl stop configure from automagically running automake

-PNGLIB_VERSION=1.6.22
+PNGLIB_VERSION=1.6.24beta03
 PNGLIB_MAJOR=1
 PNGLIB_MINOR=6
-PNGLIB_RELEASE=22
+PNGLIB_RELEASE=24

 dnl End of version number stuff

--- a/contrib/conftest/pngcp.dfa
+++ b/contrib/conftest/pngcp.dfa
@@ -0,0 +1,57 @@
+# pngcp.dfa
+#  Build time configuration of libpng
+#
+# Author: John Bowler
+# Copyright: (c) John Bowler, 2016
+# Usage rights:
+#  To the extent possible under law, the author has waived all copyright and
+#  related or neighboring rights to this work.  This work is published from:
+#  United States.
+#
+# Build libpng with support for pngcp.  This means just png_read_png,
+# png_write_png and small number of configuration settings.
+#
+everything = off
+
+# This option is specific to this configuration; it adds a #define to the
+# generated pnglibconf.h which turns on the (not portable) timing option for
+# pngcp.  Note that any option is automatically preceded by PNG_; there is no
+# way round this and this is deliberate.
+option PNGCP_TIMING
+
+# Because of the everything off above the option must also be turned on.  This
+# may not be done in one step because it is safer and avoids mis-spelled options
+# in user .dfa files to error out if an unrecognized option is turned on.
+option PNGCP_TIMING on
+
+# Options to turn on png_read_png and png_write_png:
+option INFO_IMAGE on
+option SEQUENTIAL_READ on
+option EASY_ACCESS on
+option WRITE on
+option WRITE_16BIT on
+option WRITE_FILTER on
+
+# pngcp needs this to preserve unknown chunks, switching all these on means that
+# pngcp can work without explicit known chunk reading suppport
+option UNKNOWN_CHUNKS on
+option SET_UNKNOWN_CHUNKS on
+option HANDLE_AS_UNKNOWN on
+option SAVE_UNKNOWN_CHUNKS on
+option WRITE_UNKNOWN_CHUNKS on
+
+# pngcp needs this to handle palette files with invalid indices:
+option CHECK_FOR_INVALID_INDEX on
+option GET_PALETTE_MAX on
+
+# Pre-libpng 1.7 pngcp has to stash text chunks manually, post 1.7 without this
+# text chunks should be handled as unknown ok.
+option TEXT on
+
+# this is used to turn off limits:
+option USER_LIMITS on
+option SET_USER_LIMITS on
+
+# these are are just required for specific customizations
+option WRITE_CUSTOMIZE_ZTXT_COMPRESSION on
+option WRITE_CUSTOMIZE_COMPRESSION on
--- a/contrib/intel/filter_sse2_intrinsics.c
+++ b/contrib/intel/filter_sse2_intrinsics.c
@@ -6,7 +6,7 @@
 * Derived from arm/filter_neon_intrinsics.c, which was
 * Copyright (c) 2014,2016 Glenn Randers-Pehrson
 *
- * Last changed in libpng 1.6.22 [May 26, 2016]
+ * Last changed in libpng 1.6.24 [(PENDING RELEASE)]
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
@@ -208,7 +208,7 @@ static __m128i abs_i16(__m128i x) {
   x = _mm_xor_si128(x, is_negative);

   /* +1 to negative lanes, else +0. */
-   x = _mm_add_epi16(x, _mm_srli_epi16(is_negative, 15));
+   x = _mm_sub_epi16(x, is_negative);
   return x;
 #endif
 }
--- a/contrib/intel/intel_sse.patch
+++ b/contrib/intel/intel_sse.patch
@@ -1,6 +1,6 @@
-diff --git libpng-1.6.22-orig/configure.ac libpng-1.6.22/configure.ac
--- libpng-1.6.22-orig/configure.ac	2016-05-25 18:59:10.000000000 -0400
-+++ libpng-1.6.22/configure.ac	2016-05-25 19:48:10.631751170 -0400
+diff --git a/configure.ac b/configure.ac
+--- a/configure.ac	2016-05-25 18:59:10.000000000 -0400
+++ b/configure.ac	2016-05-25 19:48:10.631751170 -0400
@@ -341,16 +341,50 @@ AC_ARG_ENABLE([arm-neon],
 
 AM_CONDITIONAL([PNG_ARM_NEON],
@@ -52,9 +52,9 @@ diff --git libpng-1.6.22-orig/configure.ac libpng-1.6.22/configure.ac
    [chmod +x libpng-config])
 
 AC_OUTPUT
-diff --git libpng-1.6.22-orig/Makefile.am libpng-1.6.22/Makefile.am
--- libpng-1.6.22-orig/Makefile.am	2016-05-17 18:15:12.000000000 -0400
-+++ libpng-1.6.22/Makefile.am	2016-05-25 19:48:10.631751170 -0400
+diff --git a/Makefile.am b/Makefile.am
+--- a/Makefile.am	2016-05-17 18:15:12.000000000 -0400
+++ b/Makefile.am	2016-05-25 19:48:10.631751170 -0400
@@ -89,16 +89,20 @@ libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SO
 	pngset.c pngtrans.c pngwio.c pngwrite.c pngwtran.c pngwutil.c\
 	png.h pngconf.h pngdebug.h pnginfo.h pngpriv.h pngstruct.h pngusr.dfa
@@ -76,9 +76,9 @@ diff --git libpng-1.6.22-orig/Makefile.am libpng-1.6.22/Makefile.am
 if HAVE_LD_VERSION_SCRIPT
 #   Versioned symbols and restricted exports
 if HAVE_SOLARIS_LD
-diff --git libpng-1.6.22-orig/pngpriv.h libpng-1.6.22/pngpriv.h
--- libpng-1.6.22-orig/pngpriv.h	2016-05-25 18:59:10.000000000 -0400
-+++ libpng-1.6.22/pngpriv.h	2016-05-25 19:48:10.635751171 -0400
+diff --git a/pngpriv.h b/pngpriv.h
+--- a/pngpriv.h	2016-05-31 09:20:34.442885047 -0500
+++ b/pngpriv.h	2016-05-31 09:14:54.583492341 -0500
@@ -177,16 +177,52 @@
 #  endif /* !PNG_ARM_NEON_IMPLEMENTATION */
 
@@ -162,3 +162,22 @@ diff --git libpng-1.6.22-orig/pngpriv.h libpng-1.6.22/pngpriv.h
 PNG_INTERNAL_FUNCTION(void,png_read_IDAT_data,(png_structrp png_ptr,
    png_bytep output, png_alloc_size_t avail_out),PNG_EMPTY);
    /* Read 'avail_out' bytes of data from the IDAT stream.  If the output buffer
+@@ -1910,16 +1959,18 @@ PNG_INTERNAL_FUNCTION(void, PNG_FILTER_O
+    /* Just declare the optimization that will be used */
+ #else
+    /* List *all* the possible optimizations here - this branch is required if
+     * the builder of libpng passes the definition of PNG_FILTER_OPTIMIZATIONS in
+     * CFLAGS in place of CPPFLAGS *and* uses symbol prefixing.
+     */
+ PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_neon,
+    (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_sse2,
+   (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);
+ 
+ /* Maintainer: Put new private prototypes here ^ */
+ 
+ #include "pngdebug.h"
--- a/contrib/libtests/pngimage.c
+++ b/contrib/libtests/pngimage.c
@@ -2,7 +2,7 @@
 *
 * Copyright (c) 2015,2016 John Cunningham Bowler
 *
- * Last changed in libpng 1.6.22 [May 26, 2016]
+ * Last changed in libpng 1.6.24 [(PENDING RELEASE)]
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
@@ -45,8 +45,19 @@
 #  define SKIP 0
 #endif

-#if defined(PNG_INFO_IMAGE_SUPPORTED) && defined(PNG_SEQUENTIAL_READ_SUPPORTED)\
-    && (defined(PNG_READ_PNG_SUPPORTED) || PNG_LIBPNG_VER < 10700)
+#if PNG_LIBPNG_VER < 10700
+   /* READ_PNG and WRITE_PNG were not defined, so: */
+#  ifdef PNG_INFO_IMAGE_SUPPORTED
+#     ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+#        define PNG_READ_PNG_SUPPORTED
+#     endif /* SEQUENTIAL_READ */
+#     ifdef PNG_WRITE_SUPPORTED
+#        define PNG_WRITE_PNG_SUPPORTED
+#     endif /* WRITE */
+#  endif /* INFO_IMAGE */
+#endif /* pre 1.7.0 */
+
+#ifdef PNG_READ_PNG_SUPPORTED
 /* If a transform is valid on both read and write this implies that if the
 * transform is applied to read it must also be applied on write to produce
 * meaningful data.  This is because these transforms when performed on read
@@ -395,7 +406,7 @@ buffer_destroy(struct buffer *buffer)
   buffer_destroy_list(list);
 }

-#ifdef PNG_WRITE_SUPPORTED
+#ifdef PNG_WRITE_PNG_SUPPORTED
 static void
 buffer_start_write(struct buffer *buffer)
 {
@@ -565,7 +576,7 @@ struct display
   png_structp    read_pp;
   png_infop      read_ip;

-#  ifdef PNG_WRITE_SUPPORTED
+#  ifdef PNG_WRITE_PNG_SUPPORTED
      /* Used to write a new image (the original info_ptr is used) */
      png_structp   write_pp;
      struct buffer written_file;   /* where the file gets written */
@@ -592,7 +603,7 @@ display_init(struct display *dp)
   dp->read_ip = NULL;
   buffer_init(&dp->original_file);

-#  ifdef PNG_WRITE_SUPPORTED
+#  ifdef PNG_WRITE_PNG_SUPPORTED
      dp->write_pp = NULL;
      buffer_init(&dp->written_file);
 #  endif
@@ -605,7 +616,7 @@ display_clean_read(struct display *dp)
      png_destroy_read_struct(&dp->read_pp, &dp->read_ip, NULL);
 }

-#ifdef PNG_WRITE_SUPPORTED
+#ifdef PNG_WRITE_PNG_SUPPORTED
 static void
 display_clean_write(struct display *dp)
 {
@@ -617,7 +628,7 @@ display_clean_write(struct display *dp)
 static void
 display_clean(struct display *dp)
 {
-#  ifdef PNG_WRITE_SUPPORTED
+#  ifdef PNG_WRITE_PNG_SUPPORTED
      display_clean_write(dp);
 #  endif
   display_clean_read(dp);
@@ -635,7 +646,7 @@ static void
 display_destroy(struct display *dp)
 {
    /* Release any memory held in the display. */
-#  ifdef PNG_WRITE_SUPPORTED
+#  ifdef PNG_WRITE_PNG_SUPPORTED
      buffer_destroy(&dp->written_file);
 #  endif

@@ -1082,6 +1093,7 @@ compare_read(struct display *dp, int applied_transforms)
      }

      else
+#     ifdef PNG_sBIT_SUPPORTED
      {
         unsigned long y;
         int bpp;   /* bits-per-pixel then bytes-per-pixel */
@@ -1243,12 +1255,16 @@ compare_read(struct display *dp, int applied_transforms)
            }
         } /* for y */
      }
+#     else /* !sBIT */
+         display_log(dp, INTERNAL_ERROR,
+               "active shift transform but no sBIT support");
+#     endif /* !sBIT */
   }

   return 1; /* compare succeeded */
 }

-#ifdef PNG_WRITE_SUPPORTED
+#ifdef PNG_WRITE_PNG_SUPPORTED
 static void
 buffer_write(struct display *dp, struct buffer *buffer, png_bytep data,
   png_size_t size)
@@ -1347,7 +1363,7 @@ write_png(struct display *dp, png_infop ip, int transforms)
    */
   display_clean_write(dp);
 }
-#endif /* WRITE_SUPPORTED */
+#endif /* WRITE_PNG */

 static int
 skip_transform(struct display *dp, int tr)
@@ -1409,7 +1425,7 @@ test_one_file(struct display *dp, const char *filename)
         return; /* no point testing more */
   }

-#ifdef PNG_WRITE_SUPPORTED
+#ifdef PNG_WRITE_PNG_SUPPORTED
   /* Second test: write the original PNG data out to a new file (to test the
    * write side) then read the result back in and make sure that it hasn't
    * changed.
@@ -1450,7 +1466,7 @@ test_one_file(struct display *dp, const char *filename)
          * out and read it back in again (without the reversible transforms)
          * we should get back to the place where we started.
          */
-#ifdef PNG_WRITE_SUPPORTED
+#ifdef PNG_WRITE_PNG_SUPPORTED
         if ((current & write_transforms) == current)
         {
            /* All transforms reversible: write the PNG with the transformations
@@ -1686,7 +1702,7 @@ main(const int argc, const char * const * const argv)
      return errors != 0;
   }
 }
-#else /* !INFO_IMAGE || !SEQUENTIAL_READ || !READ_PNG*/
+#else /* !READ_PNG */
 int
 main(void)
 {
--- a/contrib/libtests/pngstest.c
+++ b/contrib/libtests/pngstest.c
@@ -3,7 +3,7 @@
 *
 * Copyright (c) 2013-2016 John Cunningham Bowler
 *
- * Last changed in libpng 1.6.22 [May 26, 2016]
+ * Last changed in libpng 1.6.24 [(PENDING RELEASE)]
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
@@ -26,15 +26,6 @@
 #  include <config.h>
 #endif

-/* 1.6.1 added support for the configure test harness, which uses 77 to indicate
- * a skipped test, in earlier versions we need to succeed on a skipped test, so:
- */
-#if PNG_LIBPNG_VER >= 10601 && defined(HAVE_CONFIG_H)
-#  define SKIP 77
-#else
-#  define SKIP 0
-#endif
-
 /* Define the following to use this test against your installed libpng, rather
 * than the one being built here:
 */
@@ -44,6 +35,15 @@
 #  include "../../png.h"
 #endif

+/* 1.6.1 added support for the configure test harness, which uses 77 to indicate
+ * a skipped test, in earlier versions we need to succeed on a skipped test, so:
+ */
+#if PNG_LIBPNG_VER >= 10601 && defined(HAVE_CONFIG_H)
+#  define SKIP 77
+#else
+#  define SKIP 0
+#endif
+
 #ifdef PNG_SIMPLIFIED_READ_SUPPORTED /* Else nothing can be done */
 #include "../tools/sRGB.h"

--- a/contrib/libtests/pngvalid.c
+++ b/contrib/libtests/pngvalid.c
@@ -1,7 +1,7 @@

 /* pngvalid.c - validate libpng by constructing then reading png files.
 *
- * Last changed in libpng 1.6.22 [May 26, 2016]
+ * Last changed in libpng 1.6.24 [(PENDING RELEASE)]
 * Copyright (c) 2014-2016 Glenn Randers-Pehrson
 * Written by John Cunningham Bowler
 *
@@ -131,6 +131,17 @@ typedef png_byte *png_const_bytep;
 #include <string.h> /* For memcpy, memset */
 #include <math.h>   /* For floor */

+/* Convenience macros. */
+#define CHUNK(a,b,c,d) (((a)<<24)+((b)<<16)+((c)<<8)+(d))
+#define CHUNK_IHDR CHUNK(73,72,68,82)
+#define CHUNK_PLTE CHUNK(80,76,84,69)
+#define CHUNK_IDAT CHUNK(73,68,65,84)
+#define CHUNK_IEND CHUNK(73,69,78,68)
+#define CHUNK_cHRM CHUNK(99,72,82,77)
+#define CHUNK_gAMA CHUNK(103,65,77,65)
+#define CHUNK_sBIT CHUNK(115,66,73,84)
+#define CHUNK_sRGB CHUNK(115,82,71,66)
+
 /* Unused formal parameter errors are removed using the following macro which is
 * expected to have no bad effects on performance.
 */
@@ -297,38 +308,33 @@ randomize(void *pv, size_t size)

 #define R8(this) randomize(&(this), sizeof (this))

-static void r16(png_uint_16p p16, size_t count)
+#ifdef PNG_READ_SUPPORTED
+static png_byte
+random_byte(void)
 {
-   size_t i;
-
-   for (i=0; i<count; ++i)
-   {
-      unsigned char b2[2];
-      randomize(b2, sizeof b2);
-      *p16++ = png_get_uint_16(b2);
-   }
+   unsigned char b1[1];
+   randomize(b1, sizeof b1);
+   return b1[0];
 }
+#endif /* READ */

-#define R16(this) r16(&(this), (sizeof (this))/(sizeof (png_uint_16)))
-#define R16_1(this) r16(&(this), (size_t) 1U)
+static png_uint_16
+random_u16(void)
+{
+   unsigned char b2[2];
+   randomize(b2, sizeof b2);
+   return png_get_uint_16(b2);
+}

 #if defined PNG_READ_RGB_TO_GRAY_SUPPORTED ||\
    defined PNG_READ_FILLER_SUPPORTED
-static void r32(png_uint_32p p32, size_t count)
+static png_uint_32
+random_u32(void)
 {
-   size_t i;
-
-   for (i=0; i<count; ++i)
-   {
-      unsigned char b4[4];
-      randomize(b4, sizeof b4);
-      *p32++ = png_get_uint_32(b4);
-   }
+   unsigned char b4[4];
+   randomize(b4, sizeof b4);
+   return png_get_uint_32(b4);
 }
-
-#define R32(this) r32(&(this), (sizeof (this))/(sizeof (png_uint_32)))
-#define R32_1(this) r32(&(this), (size_t) 1U)
-
 #endif /* READ_FILLER || READ_RGB_TO_GRAY */

 #endif /* READ || WRITE_tRNS || WRITE_FILTER */
@@ -338,11 +344,7 @@ static void r32(png_uint_32p p32, size_t count)
 static unsigned int
 random_mod(unsigned int max)
 {
-   png_uint_16 x;
-
-   R16_1(x);
-
-   return x % max; /* 0 .. max-1 */
+   return random_u16() % max; /* 0 .. max-1 */
 }
 #endif /* READ_TRANSFORMS || WRITE_FILTER */

@@ -351,11 +353,7 @@ random_mod(unsigned int max)
 static int
 random_choice(void)
 {
-   unsigned char x;
-
-   R8(x);
-
-   return x & 1;
+   return random_byte() & 1;
 }
 #endif /* READ_RGB_TO_GRAY || READ_FILLER */

@@ -711,6 +709,8 @@ typedef struct png_store_file
 {
   struct png_store_file*  next;      /* as many as you like... */
   char                    name[FILE_NAME_SIZE];
+   unsigned int            IDAT_bits; /* Number of bits in IDAT size */
+   png_uint_32             IDAT_size; /* Total size of IDAT data */
   png_uint_32             id;        /* must be correct (see FILEID) */
   png_size_t              datacount; /* In this (the last) buffer */
   png_store_buffer        data;      /* Last buffer in file */
@@ -766,6 +766,13 @@ typedef struct png_store
   char               test[128];      /* Name of test */
   char               error[256];

+   /* Share fields */
+   png_uint_32        chunklen; /* Length of chunk+overhead (chunkpos >= 8) */
+   png_uint_32        chunktype;/* Type of chunk (valid if chunkpos >= 4) */
+   png_uint_32        chunkpos; /* Position in chunk */
+   png_uint_32        IDAT_size;/* Accumulated IDAT size in .new */
+   unsigned int       IDAT_bits;/* Cache of the file store value */
+
   /* Read fields */
   png_structp        pread;    /* Used to read a saved file */
   png_infop          piread;
@@ -775,6 +782,9 @@ typedef struct png_store
   png_byte*          image;    /* Buffer for reading interlaced images */
   png_size_t         cb_image; /* Size of this buffer */
   png_size_t         cb_row;   /* Row size of the image(s) */
+   uLong              IDAT_crc;
+   png_uint_32        IDAT_len; /* Used when re-chunking IDAT chunks */
+   png_uint_32        IDAT_pos; /* Used when re-chunking IDAT chunks */
   png_uint_32        image_h;  /* Number of rows in a single image */
   store_pool         read_memory_pool;

@@ -861,6 +871,11 @@ store_init(png_store* ps)
   ps->pwrite = NULL;
   ps->piwrite = NULL;
   ps->writepos = 0;
+   ps->chunkpos = 8;
+   ps->chunktype = 0;
+   ps->chunklen = 16;
+   ps->IDAT_size = 0;
+   ps->IDAT_bits = 0;
   ps->new.prev = NULL;
   ps->palette = NULL;
   ps->npalette = 0;
@@ -883,6 +898,11 @@ store_freenew(png_store *ps)
 {
   store_freebuffer(&ps->new);
   ps->writepos = 0;
+   ps->chunkpos = 8;
+   ps->chunktype = 0;
+   ps->chunklen = 16;
+   ps->IDAT_size = 0;
+   ps->IDAT_bits = 0;
   if (ps->palette != NULL)
   {
      free(ps->palette);
@@ -896,9 +916,6 @@ store_storenew(png_store *ps)
 {
   png_store_buffer *pb;

-   if (ps->writepos != STORE_BUFFER_SIZE)
-      png_error(ps->pwrite, "invalid store call");
-
   pb = voidcast(png_store_buffer*, malloc(sizeof *pb));

   if (pb == NULL)
@@ -929,21 +946,52 @@ store_freefile(png_store_file **ppf)
   }
 }

+static unsigned int
+bits_of(png_uint_32 num)
+{
+   /* Return the number of bits in 'num' */
+   unsigned int b = 0;
+
+   if (num & 0xffff0000U)  b += 16U, num >>= 16;
+   if (num & 0xff00U)      b += 8U, num >>= 8;
+   if (num & 0xf0U)        b += 4U, num >>= 4;
+   if (num & 0xcU)         b += 2U, num >>= 2;
+   if (num & 0x2U)         ++b, num >>= 1;
+   if (num)                ++b;
+
+   return b; /* 0..32 */
+}
+
 /* Main interface to file storeage, after writing a new PNG file (see the API
 * below) call store_storefile to store the result with the given name and id.
 */
 static void
 store_storefile(png_store *ps, png_uint_32 id)
 {
-   png_store_file *pf = voidcast(png_store_file*, malloc(sizeof *pf));
+   png_store_file *pf;
+
+   if (ps->chunkpos != 0U || ps->chunktype != 0U || ps->chunklen != 0U ||
+       ps->IDAT_size == 0)
+      png_error(ps->pwrite, "storefile: incomplete write");
+
+   pf = voidcast(png_store_file*, malloc(sizeof *pf));
   if (pf == NULL)
      png_error(ps->pwrite, "storefile: OOM");
   safecat(pf->name, sizeof pf->name, 0, ps->wname);
   pf->id = id;
   pf->data = ps->new;
   pf->datacount = ps->writepos;
+   pf->IDAT_size = ps->IDAT_size;
+   pf->IDAT_bits = bits_of(ps->IDAT_size);
+   /* Because the IDAT always has zlib header stuff this must be true: */
+   if (pf->IDAT_bits == 0U)
+      png_error(ps->pwrite, "storefile: 0 sized IDAT");
   ps->new.prev = NULL;
   ps->writepos = 0;
+   ps->chunkpos = 8;
+   ps->chunktype = 0;
+   ps->chunklen = 16;
+   ps->IDAT_size = 0;
   pf->palette = ps->palette;
   pf->npalette = ps->npalette;
   ps->palette = 0;
@@ -1067,7 +1115,7 @@ store_warning(png_structp ppIn, png_const_charp message)
   if (!ps->expect_warning)
      store_log(ps, pp, message, 0 /* warning */);
   else
-      ps->saw_warning = 1;
+     ps->saw_warning = 1;
 }

 /* These somewhat odd functions are used when reading an image to ensure that
@@ -1209,32 +1257,119 @@ store_image_check(const png_store* ps, png_const_structp pp, int iImage)
 }
 #endif /* PNG_READ_SUPPORTED */

+static int
+valid_chunktype(png_uint_32 chunktype)
+{
+   /* Each byte in the chunk type must be in one of the ranges 65..90, 97..122
+    * (both inclusive), so:
+    */
+   unsigned int i;
+
+   for (i=0; i<4; ++i)
+   {
+      unsigned int c = chunktype & 0xffU;
+
+      if (!((c >= 65U && c <= 90U) || (c >= 97U && c <= 122U)))
+         return 0;
+
+      chunktype >>= 8;
+   }
+
+   return 1; /* It's valid */
+}
+
 static void PNGCBAPI
 store_write(png_structp ppIn, png_bytep pb, png_size_t st)
 {
   png_const_structp pp = ppIn;
   png_store *ps = voidcast(png_store*, png_get_io_ptr(pp));
+   size_t writepos = ps->writepos;
+   png_uint_32 chunkpos = ps->chunkpos;
+   png_uint_32 chunktype = ps->chunktype;
+   png_uint_32 chunklen = ps->chunklen;

   if (ps->pwrite != pp)
      png_error(pp, "store state damaged");

+   /* Technically this is legal, but in practice libpng never writes more than
+    * the maximum chunk size at once so if it happens something weird has
+    * changed inside libpng (probably).
+    */
+   if (st > 0x7fffffffU)
+      png_error(pp, "unexpected write size");
+
+   /* Now process the bytes to be written.  Do this in units of the space in the
+    * output (write) buffer or, at the start 4 bytes for the chunk type and
+    * length limited in any case by the amount of data.
+    */
   while (st > 0)
   {
-      size_t cb;
+      if (writepos >= STORE_BUFFER_SIZE)
+         store_storenew(ps), writepos = 0;

-      if (ps->writepos >= STORE_BUFFER_SIZE)
-         store_storenew(ps);
+      if (chunkpos < 4)
+      {
+         png_byte b = *pb++;
+         --st;
+         chunklen = (chunklen << 8) + b;
+         ps->new.buffer[writepos++] = b;
+         ++chunkpos;
+      }

-      cb = st;
+      else if (chunkpos < 8)
+      {
+         png_byte b = *pb++;
+         --st;
+         chunktype = (chunktype << 8) + b;
+         ps->new.buffer[writepos++] = b;

-      if (cb > STORE_BUFFER_SIZE - ps->writepos)
-         cb = STORE_BUFFER_SIZE - ps->writepos;
+         if (++chunkpos == 8)
+         {
+            chunklen &= 0xffffffffU;
+            if (chunklen > 0x7fffffffU)
+               png_error(pp, "chunk length too great");

-      memcpy(ps->new.buffer + ps->writepos, pb, cb);
-      pb += cb;
-      st -= cb;
-      ps->writepos += cb;
-   }
+            chunktype &= 0xffffffffU;
+            if (chunktype == CHUNK_IDAT)
+            {
+               if (chunklen > ~ps->IDAT_size)
+                  png_error(pp, "pngvalid internal image too large");
+
+               ps->IDAT_size += chunklen;
+            }
+
+            else if (!valid_chunktype(chunktype))
+               png_error(pp, "invalid chunk type");
+
+            chunklen += 12; /* for header and CRC */
+         }
+      }
+
+      else /* chunkpos >= 8 */
+      {
+         png_size_t cb = st;
+
+         if (cb > STORE_BUFFER_SIZE - writepos)
+            cb = STORE_BUFFER_SIZE - writepos;
+
+         if (cb  > chunklen - chunkpos/* bytes left in chunk*/)
+            cb = (png_size_t)/*SAFE*/(chunklen - chunkpos);
+
+         memcpy(ps->new.buffer + writepos, pb, cb);
+         chunkpos += (png_uint_32)/*SAFE*/cb;
+         pb += cb;
+         writepos += cb;
+         st -= cb;
+
+         if (chunkpos >= chunklen) /* must be equal */
+            chunkpos = chunktype = chunklen = 0;
+      }
+   } /* while (st > 0) */
+
+   ps->writepos = writepos;
+   ps->chunkpos = chunkpos;
+   ps->chunktype = chunktype;
+   ps->chunklen = chunklen;
 }

 static void PNGCBAPI
@@ -1254,7 +1389,6 @@ store_read_buffer_size(png_store *ps)
   return ps->current->datacount;
 }

-#ifdef PNG_READ_TRANSFORMS_SUPPORTED
 /* Return total bytes available for read. */
 static size_t
 store_read_buffer_avail(png_store *ps)
@@ -1279,7 +1413,6 @@ store_read_buffer_avail(png_store *ps)

   return 0;
 }
-#endif

 static int
 store_read_buffer_next(png_store *ps)
@@ -1331,6 +1464,240 @@ store_read_imp(png_store *ps, png_bytep pb, png_size_t st)
   }
 }

+static png_size_t
+store_read_chunk(png_store *ps, png_bytep pb, const png_size_t max,
+      const png_size_t min)
+{
+   png_uint_32 chunklen = ps->chunklen;
+   png_uint_32 chunktype = ps->chunktype;
+   png_uint_32 chunkpos = ps->chunkpos;
+   png_size_t st = max;
+
+   if (st > 0) do
+   {
+      if (chunkpos >= chunklen) /* end of last chunk */
+      {
+         png_byte buffer[8];
+
+         /* Read the header of the next chunk: */
+         store_read_imp(ps, buffer, 8U);
+         chunklen = png_get_uint_32(buffer) + 12U;
+         chunktype = png_get_uint_32(buffer+4U);
+         chunkpos = 0U; /* Position read so far */
+      }
+
+      if (chunktype == CHUNK_IDAT)
+      {
+         png_uint_32 IDAT_pos = ps->IDAT_pos;
+         png_uint_32 IDAT_len = ps->IDAT_len;
+         png_uint_32 IDAT_size = ps->IDAT_size;
+
+         /* The IDAT headers are constructed here; skip the input header. */
+         if (chunkpos < 8U)
+            chunkpos = 8U;
+
+         if (IDAT_pos == IDAT_len)
+         {
+            png_byte random = random_byte();
+
+            /* Make a new IDAT chunk, if IDAT_len is 0 this is the first IDAT,
+             * if IDAT_size is 0 this is the end.  At present this is set up
+             * using a random number so that there is a 25% chance before
+             * the start of the first IDAT chunk being 0 length.
+             */
+            if (IDAT_len == 0U) /* First IDAT */
+            {
+               switch (random & 3U)
+               {
+                  case 0U: IDAT_len = 12U; break; /* 0 bytes */
+                  case 1U: IDAT_len = 13U; break; /* 1 byte */
+                  default: IDAT_len = random_u32();
+                           IDAT_len %= IDAT_size;
+                           IDAT_len += 13U; /* 1..IDAT_size bytes */
+                           break;
+               }
+            }
+
+            else if (IDAT_size == 0U) /* all IDAT data read */
+            {
+               /* The last (IDAT) chunk should be positioned at the CRC now: */
+               if (chunkpos != chunklen-4U)
+                  png_error(ps->pread, "internal: IDAT size mismatch");
+
+               /* The only option here is to add a zero length IDAT, this
+                * happens 25% of the time.  Because of the check above
+                * chunklen-4U-chunkpos must be zero, we just need to skip the
+                * CRC now.
+                */
+               if ((random & 3U) == 0U)
+                  IDAT_len = 12U; /* Output another 0 length IDAT */
+
+               else
+               {
+                  /* End of IDATs, skip the CRC to make the code above load the
+                   * next chunk header next time round.
+                   */
+                  png_byte buffer[4];
+
+                  store_read_imp(ps, buffer, 4U);
+                  chunkpos += 4U;
+                  ps->IDAT_pos = IDAT_pos;
+                  ps->IDAT_len = IDAT_len;
+                  ps->IDAT_size = 0U;
+                  continue; /* Read the next chunk */
+               }
+            }
+
+            else
+            {
+               /* Middle of IDATs, use 'random' to determine the number of bits
+                * to use in the IDAT length.
+                */
+               IDAT_len = random_u32();
+               IDAT_len &= (1U << (1U + random % ps->IDAT_bits)) - 1U;
+               if (IDAT_len > IDAT_size)
+                  IDAT_len = IDAT_size;
+               IDAT_len += 12U; /* zero bytes may occur */
+            }
+
+            IDAT_pos = 0U;
+            ps->IDAT_crc = 0x35af061e; /* Ie: crc32(0UL, "IDAT", 4) */
+         } /* IDAT_pos == IDAT_len */
+
+         if (IDAT_pos < 8U) /* Return the header */ do
+         {
+            png_uint_32 b;
+            unsigned int shift;
+
+            if (IDAT_pos < 4U)
+               b = IDAT_len - 12U;
+
+            else
+               b = CHUNK_IDAT;
+
+            shift = 3U & IDAT_pos;
+            ++IDAT_pos;
+
+            if (shift < 3U)
+               b >>= 8U*(3U-shift);
+
+            *pb++ = 0xffU & b;
+         }
+         while (--st > 0 && IDAT_pos < 8);
+
+         else if (IDAT_pos < IDAT_len - 4U) /* I.e not the CRC */
+         {
+            if (chunkpos < chunklen-4U)
+            {
+               uInt avail = (uInt)-1;
+
+               if (avail > (IDAT_len-4U) - IDAT_pos)
+                  avail = (uInt)/*SAFE*/((IDAT_len-4U) - IDAT_pos);
+
+               if (avail > st)
+                  avail = (uInt)/*SAFE*/st;
+
+               if (avail > (chunklen-4U) - chunkpos)
+                  avail = (uInt)/*SAFE*/((chunklen-4U) - chunkpos);
+
+               store_read_imp(ps, pb, avail);
+               ps->IDAT_crc = crc32(ps->IDAT_crc, pb, avail);
+               pb += (png_size_t)/*SAFE*/avail;
+               st -= (png_size_t)/*SAFE*/avail;
+               chunkpos += (png_uint_32)/*SAFE*/avail;
+               IDAT_size -= (png_uint_32)/*SAFE*/avail;
+               IDAT_pos += (png_uint_32)/*SAFE*/avail;
+            }
+
+            else /* skip the input CRC */
+            {
+               png_byte buffer[4];
+
+               store_read_imp(ps, buffer, 4U);
+               chunkpos += 4U;
+            }
+         }
+
+         else /* IDAT crc */ do
+         {
+            uLong b = ps->IDAT_crc;
+            unsigned int shift = (IDAT_len - IDAT_pos); /* 4..1 */
+            ++IDAT_pos;
+
+            if (shift > 1U)
+               b >>= 8U*(shift-1U);
+
+            *pb++ = 0xffU & b;
+         }
+         while (--st > 0 && IDAT_pos < IDAT_len);
+
+         ps->IDAT_pos = IDAT_pos;
+         ps->IDAT_len = IDAT_len;
+         ps->IDAT_size = IDAT_size;
+      }
+
+      else /* !IDAT */
+      {
+         /* If there is still some pending IDAT data after the IDAT chunks have
+          * been processed there is a problem:
+          */
+         if (ps->IDAT_len > 0 && ps->IDAT_size > 0)
+            png_error(ps->pread, "internal: missing IDAT data");
+
+         if (chunktype == CHUNK_IEND && ps->IDAT_len == 0U)
+            png_error(ps->pread, "internal: missing IDAT");
+
+         if (chunkpos < 8U) /* Return the header */ do
+         {
+            png_uint_32 b;
+            unsigned int shift;
+
+            if (chunkpos < 4U)
+               b = chunklen - 12U;
+
+            else
+               b = chunktype;
+
+            shift = 3U & chunkpos;
+            ++chunkpos;
+
+            if (shift < 3U)
+               b >>= 8U*(3U-shift);
+
+            *pb++ = 0xffU & b;
+         }
+         while (--st > 0 && chunkpos < 8);
+
+         else /* Return chunk bytes, including the CRC */
+         {
+            png_size_t avail = st;
+
+            if (avail > chunklen - chunkpos)
+               avail = (png_size_t)/*SAFE*/(chunklen - chunkpos);
+
+            store_read_imp(ps, pb, avail);
+            pb += avail;
+            st -= avail;
+            chunkpos += (png_uint_32)/*SAFE*/avail;
+
+            /* Check for end of chunk and end-of-file; don't try to read a new
+             * chunk header at this point unless instructed to do so by 'min'.
+             */
+            if (chunkpos >= chunklen && max-st >= min &&
+                     store_read_buffer_avail(ps) == 0)
+               break;
+         }
+      } /* !IDAT */
+   }
+   while (st > 0);
+
+   ps->chunklen = chunklen;
+   ps->chunktype = chunktype;
+   ps->chunkpos = chunkpos;
+
+   return st; /* space left */
+}
+
 static void PNGCBAPI
 store_read(png_structp ppIn, png_bytep pb, png_size_t st)
 {
@@ -1340,26 +1707,33 @@ store_read(png_structp ppIn, png_bytep pb, png_size_t st)
   if (ps == NULL || ps->pread != pp)
      png_error(pp, "bad store read call");

-   store_read_imp(ps, pb, st);
+   store_read_chunk(ps, pb, st, st);
 }

 static void
 store_progressive_read(png_store *ps, png_structp pp, png_infop pi)
 {
-   /* Notice that a call to store_read will cause this function to fail because
-    * readpos will be set.
-    */
   if (ps->pread != pp || ps->current == NULL || ps->next == NULL)
      png_error(pp, "store state damaged (progressive)");

-   do
+   /* This is another Horowitz and Hill random noise generator.  In this case
+    * the aim is to stress the progressive reader with truly horrible variable
+    * buffer sizes in the range 1..500, so a sequence of 9 bit random numbers
+    * is generated.  We could probably just count from 1 to 32767 and get as
+    * good a result.
+    */
+   while (store_read_buffer_avail(ps) > 0)
   {
-      if (ps->readpos != 0)
-         png_error(pp, "store_read called during progressive read");
+      static png_uint_32 noise = 2;
+      png_size_t cb;
+      png_byte buffer[512];

-      png_process_data(pp, pi, ps->next->buffer, store_read_buffer_size(ps));
+      /* Generate 15 more bits of stuff: */
+      noise = (noise << 9) | ((noise ^ (noise >> (9-5))) & 0x1ff);
+      cb = noise & 0x1ff;
+      cb -= store_read_chunk(ps, buffer, cb, 1);
+      png_process_data(pp, pi, buffer, cb);
   }
-   while (store_read_buffer_next(ps));
 }
 #endif /* PNG_READ_SUPPORTED */

@@ -1730,6 +2104,11 @@ store_read_reset(png_store *ps)
   ps->next = NULL;
   ps->readpos = 0;
   ps->validated = 0;
+
+   ps->chunkpos = 8;
+   ps->chunktype = 0;
+   ps->chunklen = 16;
+   ps->IDAT_size = 0;
 }

 #ifdef PNG_READ_SUPPORTED
@@ -1744,6 +2123,11 @@ store_read_set(png_store *ps, png_uint_32 id)
      {
         ps->current = pf;
         ps->next = NULL;
+         ps->IDAT_size = pf->IDAT_size;
+         ps->IDAT_bits = pf->IDAT_bits; /* just a cache */
+         ps->IDAT_len = 0;
+         ps->IDAT_pos = 0;
+         ps->IDAT_crc = 0UL;
         store_read_buffer_next(ps);
         return;
      }
@@ -2581,17 +2965,6 @@ modifier_color_encoding_is_set(const png_modifier *pm)
   return pm->current_gamma != 0;
 }

-/* Convenience macros. */
-#define CHUNK(a,b,c,d) (((a)<<24)+((b)<<16)+((c)<<8)+(d))
-#define CHUNK_IHDR CHUNK(73,72,68,82)
-#define CHUNK_PLTE CHUNK(80,76,84,69)
-#define CHUNK_IDAT CHUNK(73,68,65,84)
-#define CHUNK_IEND CHUNK(73,69,78,68)
-#define CHUNK_cHRM CHUNK(99,72,82,77)
-#define CHUNK_gAMA CHUNK(103,65,77,65)
-#define CHUNK_sBIT CHUNK(115,66,73,84)
-#define CHUNK_sRGB CHUNK(115,82,71,66)
-
 /* The guts of modification are performed during a read. */
 static void
 modifier_crc(png_bytep buffer)
@@ -2631,7 +3004,7 @@ modifier_read_imp(png_modifier *pm, png_bytep pb, png_size_t st)
      {
         static png_byte sign[8] = { 137, 80, 78, 71, 13, 10, 26, 10 };
         case modifier_start:
-            store_read_imp(&pm->this, pm->buffer, 8); /* size of signature. */
+            store_read_chunk(&pm->this, pm->buffer, 8, 8); /* signature. */
            pm->buffer_count = 8;
            pm->buffer_position = 0;

@@ -2641,7 +3014,7 @@ modifier_read_imp(png_modifier *pm, png_bytep pb, png_size_t st)
            break;

         case modifier_signature:
-            store_read_imp(&pm->this, pm->buffer, 13+12); /* size of IHDR */
+            store_read_chunk(&pm->this, pm->buffer, 13+12, 13+12); /* IHDR */
            pm->buffer_count = 13+12;
            pm->buffer_position = 0;

@@ -2682,7 +3055,7 @@ modifier_read_imp(png_modifier *pm, png_bytep pb, png_size_t st)
            {
               if (cb > st) cb = st;
               pm->flush -= cb;
-               store_read_imp(&pm->this, pb, cb);
+               store_read_chunk(&pm->this, pb, cb, cb);
               pb += cb;
               st -= cb;
               if (st == 0) return;
@@ -2699,7 +3072,7 @@ modifier_read_imp(png_modifier *pm, png_bytep pb, png_size_t st)
               pm->pending_chunk = 0;
            }
            else
-               store_read_imp(&pm->this, pm->buffer, 8);
+               store_read_chunk(&pm->this, pm->buffer, 8, 8);

            pm->buffer_count = 8;
            pm->buffer_position = 0;
@@ -2765,8 +3138,8 @@ modifier_read_imp(png_modifier *pm, png_bytep pb, png_size_t st)
             */
            if (len+12 <= sizeof pm->buffer)
            {
-               store_read_imp(&pm->this, pm->buffer+pm->buffer_count,
-                   len+12-pm->buffer_count);
+               png_size_t s = len+12-pm->buffer_count;
+               store_read_chunk(&pm->this, pm->buffer+pm->buffer_count, s, s);
               pm->buffer_count = len+12;

               /* Check for a modification, else leave it be. */
@@ -3333,8 +3706,8 @@ set_random_tRNS(png_structp pp, png_infop pi, const png_byte colour_type,
   {
      if (bit_depth == 8)
      {
-         R16(tRNS.red);
-         R16(tRNS.green);
+         tRNS.red = random_u16();
+         tRNS.green = random_u16();
         tRNS.blue = tRNS.red ^ tRNS.green;
         tRNS.red &= mask;
         tRNS.green &= mask;
@@ -3343,7 +3716,7 @@ set_random_tRNS(png_structp pp, png_infop pi, const png_byte colour_type,

      else /* bit_depth == 16 */
      {
-         R16(tRNS.red);
+         tRNS.red = random_u16();
         tRNS.green = (png_uint_16)(tRNS.red * 257);
         tRNS.blue = (png_uint_16)(tRNS.green * 17);
      }
@@ -3351,7 +3724,7 @@ set_random_tRNS(png_structp pp, png_infop pi, const png_byte colour_type,

   else
   {
-      R16(tRNS.gray);
+      tRNS.gray = random_u16();
      tRNS.gray &= mask;
   }

@@ -7303,7 +7676,7 @@ image_transform_png_set_rgb_to_gray_ini(const image_transform *this,
      png_uint_32 ru;
      double total;

-      R32_1(ru);
+      ru = random_u32();
      data.green_coefficient = total = (ru & 0xffff) / 65535.;
      ru >>= 16;
      data.red_coefficient = (1 - total) * (ru & 0xffff) / 65535.;
@@ -8231,7 +8604,7 @@ image_transform_png_set_filler_set(const image_transform *this,
    * filler.  The 'filler' value has all 32 bits set, but only bit_depth
    * will be used.  At this point we don't know bit_depth.
    */
-   R32(data.filler);
+   data.filler = random_u32();
   data.flags = random_choice();

   png_set_filler(pp, data.filler, data.flags);
@@ -8304,7 +8677,7 @@ image_transform_png_set_add_alpha_set(const image_transform *this,
    * filler.  The 'filler' value has all 32 bits set, but only bit_depth
    * will be used.  At this point we don't know bit_depth.
    */
-   R32(data.filler);
+   data.filler = random_u32();
   data.flags = random_choice();

   png_set_add_alpha(pp, data.filler, data.flags);
--- a/contrib/tools/pngcp.c
+++ b/contrib/tools/pngcp.c
--- a/libpng-manual.txt
+++ b/libpng-manual.txt
@@ -1,6 +1,6 @@
 libpng-manual.txt - A description on how to use and modify libpng

- libpng version 1.6.22 - May 26, 2016
+ libpng version 1.6.24beta03 - July 4, 2016
 Updated and distributed by Glenn Randers-Pehrson
 <glennrp at users.sourceforge.net>
 Copyright (c) 1998-2016 Glenn Randers-Pehrson
@@ -11,7 +11,7 @@ libpng-manual.txt - A description on how to use and modify libpng

 Based on:

- libpng versions 0.97, January 1998, through 1.6.22 - May 26, 2016
+ libpng versions 0.97, January 1998, through 1.6.24beta03 - July 4, 2016
 Updated and distributed by Glenn Randers-Pehrson
 Copyright (c) 1998-2016 Glenn Randers-Pehrson

@@ -559,7 +559,7 @@ non-interlaced case the row that was just handled is simply one less than the
 passed in row number, and pass will always be 0.  For the interlaced case the
 same applies unless the row value is 0, in which case the row just handled was
 the last one from one of the preceding passes.  Because interlacing may skip a
-pass you cannot be sure that the preceding pass is just 'pass-1', if you really
+pass you cannot be sure that the preceding pass is just 'pass-1'; if you really
 need to know what the last pass is record (row,pass) from the callback and use
 the last recorded value each time.

@@ -2230,7 +2230,8 @@ is exactly the same.  If you are planning on displaying the image
 after each pass, the "rectangle" effect is generally considered the
 better looking one.

-If you only want the "sparkle" effect, just call png_read_rows() as
+If you only want the "sparkle" effect, just call png_read_row() or
+png_read_rows() as
 normal, with the third parameter NULL.  Make sure you make pass over
 the image number_of_passes times, and you don't change the data in the
 rows between calls.  You can change the locations of the data, just
@@ -2239,6 +2240,8 @@ pass, and assumes the data from previous passes is still valid.

    png_read_rows(png_ptr, row_pointers, NULL,
        number_of_rows);
+    or
+    png_read_row(png_ptr, row_pointers, NULL);

 If you only want the first effect (the rectangles), do the same as
 before except pass the row buffer in the third parameter, and leave
@@ -2246,6 +2249,8 @@ the second parameter NULL.

    png_read_rows(png_ptr, NULL, row_pointers,
        number_of_rows);
+    or
+    png_read_row(png_ptr, NULL, row_pointers);

 If you don't want libpng to handle the interlacing details, just call
 png_read_rows() PNG_INTERLACE_ADAM7_PASSES times to read in all the images.
@@ -5345,7 +5350,7 @@ Since the PNG Development group is an ad-hoc body, we can't make
 an official declaration.

 This is your unofficial assurance that libpng from version 0.71 and
-upward through 1.6.22 are Y2K compliant.  It is my belief that earlier
+upward through 1.6.24beta03 are Y2K compliant.  It is my belief that earlier
 versions were also Y2K compliant.

 Libpng only has two year fields.  One is a 2-byte unsigned integer
--- a/libpng.3
+++ b/libpng.3
@@ -1,6 +1,6 @@
-.TH LIBPNG 3 "May 26, 2016"
+.TH LIBPNG 3 "July 4, 2016"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.6.22
+libpng \- Portable Network Graphics (PNG) Reference Library 1.6.24beta03
 .SH SYNOPSIS
 \fB
 #include <png.h>\fP
@@ -510,7 +510,7 @@ Following is a copy of the libpng-manual.txt file that accompanies libpng.
 .SH LIBPNG.TXT
 libpng-manual.txt - A description on how to use and modify libpng

- libpng version 1.6.22 - May 26, 2016
+ libpng version 1.6.24beta03 - July 4, 2016
 Updated and distributed by Glenn Randers-Pehrson
 <glennrp at users.sourceforge.net>
 Copyright (c) 1998-2016 Glenn Randers-Pehrson
@@ -521,7 +521,7 @@ libpng-manual.txt - A description on how to use and modify libpng

 Based on:

- libpng versions 0.97, January 1998, through 1.6.22 - May 26, 2016
+ libpng versions 0.97, January 1998, through 1.6.24beta03 - July 4, 2016
 Updated and distributed by Glenn Randers-Pehrson
 Copyright (c) 1998-2016 Glenn Randers-Pehrson

@@ -1069,7 +1069,7 @@ non-interlaced case the row that was just handled is simply one less than the
 passed in row number, and pass will always be 0.  For the interlaced case the
 same applies unless the row value is 0, in which case the row just handled was
 the last one from one of the preceding passes.  Because interlacing may skip a
-pass you cannot be sure that the preceding pass is just 'pass\-1', if you really
+pass you cannot be sure that the preceding pass is just 'pass\-1'; if you really
 need to know what the last pass is record (row,pass) from the callback and use
 the last recorded value each time.

@@ -2740,7 +2740,8 @@ is exactly the same.  If you are planning on displaying the image
 after each pass, the "rectangle" effect is generally considered the
 better looking one.

-If you only want the "sparkle" effect, just call png_read_rows() as
+If you only want the "sparkle" effect, just call png_read_row() or
+png_read_rows() as
 normal, with the third parameter NULL.  Make sure you make pass over
 the image number_of_passes times, and you don't change the data in the
 rows between calls.  You can change the locations of the data, just
@@ -2749,6 +2750,8 @@ pass, and assumes the data from previous passes is still valid.

    png_read_rows(png_ptr, row_pointers, NULL,
        number_of_rows);
+    or
+    png_read_row(png_ptr, row_pointers, NULL);

 If you only want the first effect (the rectangles), do the same as
 before except pass the row buffer in the third parameter, and leave
@@ -2756,6 +2759,8 @@ the second parameter NULL.

    png_read_rows(png_ptr, NULL, row_pointers,
        number_of_rows);
+    or
+    png_read_row(png_ptr, NULL, row_pointers);

 If you don't want libpng to handle the interlacing details, just call
 png_read_rows() PNG_INTERLACE_ADAM7_PASSES times to read in all the images.
@@ -5855,7 +5860,7 @@ Since the PNG Development group is an ad-hoc body, we can't make
 an official declaration.

 This is your unofficial assurance that libpng from version 0.71 and
-upward through 1.6.22 are Y2K compliant.  It is my belief that earlier
+upward through 1.6.24beta03 are Y2K compliant.  It is my belief that earlier
 versions were also Y2K compliant.

 Libpng only has two year fields.  One is a 2-byte unsigned integer
@@ -5957,7 +5962,7 @@ the first widely used release:
 ...
 1.5.27                  15    10527  15.so.15.27[.0]
 ...
- 1.6.22                  16    10622  16.so.16.22[.0]
+ 1.6.24                  16    10624  16.so.16.24[.0]

 Henceforth the source version will match the shared-library minor
 and patch numbers; the shared-library major version number will be
@@ -6013,7 +6018,7 @@ possible without all of you.

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

-Libpng version 1.6.22 - May 26, 2016:
+Libpng version 1.6.24beta03 - July 4, 2016:
 Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc.
 Currently maintained by Glenn Randers-Pehrson (glennrp at users.sourceforge.net).

@@ -6038,7 +6043,7 @@ this sentence.

 This code is released under the libpng license.

-libpng versions 1.0.7, July 1, 2000 through 1.6.22, May 26, 2016 are
+libpng versions 1.0.7, July 1, 2000 through 1.6.24beta03, July 4, 2016 are
 Copyright (c) 2000-2002, 2004, 2006-2016 Glenn Randers-Pehrson, are
 derived from libpng-1.0.6, and are distributed according to the same
 disclaimer and license as libpng-1.0.6 with the following individuals
@@ -6163,7 +6168,7 @@ files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).

 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-May 26, 2016
+July 4, 2016

 .\" end of man page

--- a/libpngpf.3
+++ b/libpngpf.3
@@ -1,6 +1,6 @@
-.TH LIBPNGPF 3 "May 26, 2016"
+.TH LIBPNGPF 3 "July 4, 2016"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.6.22
+libpng \- Portable Network Graphics (PNG) Reference Library 1.6.24beta03
 (private functions)
 .SH SYNOPSIS
 \fB#include \fI"pngpriv.h"
--- a/png.5
+++ b/png.5
@@ -1,4 +1,4 @@
-.TH PNG 5 "May 26, 2016"
+.TH PNG 5 "July 4, 2016"
 .SH NAME
 png \- Portable Network Graphics (PNG) format
 .SH DESCRIPTION
@@ -35,7 +35,7 @@ PNG 1.0 specification, October 1996:
 RFC 2083
 .IP
 .br
-ftp://ds.internic.net/rfc/rfc2083.txt
+http://www.ietf.org/rfc/rfc2083.txt
 .br
 or (as a W3C Recommendation) at
 .br
--- a/png.c
+++ b/png.c
@@ -14,7 +14,7 @@
 #include "pngpriv.h"

 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef png_libpng_version_1_6_22 Your_png_h_is_not_version_1_6_22;
+typedef png_libpng_version_1_6_24beta03 Your_png_h_is_not_version_1_6_24beta03;

 /* Tells libpng that we have already handled the first "num_bytes" bytes
 * of the PNG file signature.  If the PNG data is embedded into another
@@ -775,14 +775,14 @@ png_get_copyright(png_const_structrp png_ptr)
 #else
 #  ifdef __STDC__
   return PNG_STRING_NEWLINE \
-      "libpng version 1.6.22 - May 26, 2016" PNG_STRING_NEWLINE \
+      "libpng version 1.6.24beta03 - July 4, 2016" PNG_STRING_NEWLINE \
      "Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson" \
      PNG_STRING_NEWLINE \
      "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \
      "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \
      PNG_STRING_NEWLINE;
 #  else
-   return "libpng version 1.6.22 - May 26, 2016\
+   return "libpng version 1.6.24beta03 - July 4, 2016\
      Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson\
      Copyright (c) 1996-1997 Andreas Dilger\
      Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.";
@@ -2354,7 +2354,6 @@ png_compare_ICC_profile_with_sRGB(png_const_structrp png_ptr,

   return 0; /* no match */
 }
-#endif /* PNG_sRGB_PROFILE_CHECKS >= 0 */

 void /* PRIVATE */
 png_icc_set_sRGB(png_const_structrp png_ptr,
@@ -2363,12 +2362,11 @@ png_icc_set_sRGB(png_const_structrp png_ptr,
   /* Is this profile one of the known ICC sRGB profiles?  If it is, just set
    * the sRGB information.
    */
-#if PNG_sRGB_PROFILE_CHECKS >= 0
   if (png_compare_ICC_profile_with_sRGB(png_ptr, profile, adler) != 0)
-#endif
      (void)png_colorspace_set_sRGB(png_ptr, colorspace,
         (int)/*already checked*/png_get_uint_32(profile+64));
 }
+#endif /* PNG_sRGB_PROFILE_CHECKS >= 0 */
 #endif /* sRGB */

 int /* PRIVATE */
@@ -2385,7 +2383,7 @@ png_colorspace_set_ICC(png_const_structrp png_ptr, png_colorspacerp colorspace,
       png_icc_check_tag_table(png_ptr, colorspace, name, profile_length,
          profile) != 0)
   {
-#     ifdef PNG_sRGB_SUPPORTED
+#     if defined(PNG_sRGB_SUPPORTED) && PNG_sRGB_PROFILE_CHECKS >= 0
         /* If no sRGB support, don't try storing sRGB information */
         png_icc_set_sRGB(png_ptr, colorspace, profile, 0);
 #     endif
--- a/png.h
+++ b/png.h
@@ -1,7 +1,7 @@

 /* png.h - header file for PNG reference library
 *
- * libpng version 1.6.22, May 26, 2016
+ * libpng version 1.6.24beta03, July 4, 2016
 *
 * Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -12,7 +12,7 @@
 * Authors and maintainers:
 *   libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
 *   libpng versions 0.89, June 1996, through 0.96, May 1997: Andreas Dilger
- *   libpng versions 0.97, January 1998, through 1.6.22, May 26, 2016:
+ *   libpng versions 0.97, January 1998, through 1.6.24beta03, July 4, 2016:
 *     Glenn Randers-Pehrson.
 *   See also "Contributing Authors", below.
 */
@@ -29,7 +29,7 @@
 * files that are distributed with libpng have other copyright owners and
 * are released under other open source licenses.
 *
- * libpng versions 1.0.7, July 1, 2000 through 1.6.22, May 26, 2016 are
+ * libpng versions 1.0.7, July 1, 2000 through 1.6.24beta03, July 4, 2016 are
 * Copyright (c) 2000-2002, 2004, 2006-2016 Glenn Randers-Pehrson, are
 * derived from libpng-1.0.6, and are distributed according to the same
 * disclaimer and license as libpng-1.0.6 with the following individuals
@@ -217,7 +217,7 @@
 *    ...
 *    1.5.27                  15    10527  15.so.15.27[.0]
 *    ...
- *    1.6.22                  16    10622  16.so.16.22[.0]
+ *    1.6.24                  16    10624  16.so.16.24[.0]
 *
 *    Henceforth the source version will match the shared-library major
 *    and minor numbers; the shared-library major version number will be
@@ -245,13 +245,13 @@
 * Y2K compliance in libpng:
 * =========================
 *
- *    May 26, 2016
+ *    July 4, 2016
 *
 *    Since the PNG Development group is an ad-hoc body, we can't make
 *    an official declaration.
 *
 *    This is your unofficial assurance that libpng from version 0.71 and
- *    upward through 1.6.22 are Y2K compliant.  It is my belief that
+ *    upward through 1.6.24beta03 are Y2K compliant.  It is my belief that
 *    earlier versions were also Y2K compliant.
 *
 *    Libpng only has two year fields.  One is a 2-byte unsigned integer
@@ -313,9 +313,9 @@
 */

 /* Version information for png.h - this should match the version in png.c */
-#define PNG_LIBPNG_VER_STRING "1.6.22"
+#define PNG_LIBPNG_VER_STRING "1.6.24beta03"
 #define PNG_HEADER_VERSION_STRING \
-     " libpng version 1.6.22 - May 26, 2016\n"
+     " libpng version 1.6.24beta03 - July 4, 2016\n"

 #define PNG_LIBPNG_VER_SONUM   16
 #define PNG_LIBPNG_VER_DLLNUM  16
@@ -323,13 +323,13 @@
 /* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
 #define PNG_LIBPNG_VER_MAJOR   1
 #define PNG_LIBPNG_VER_MINOR   6
-#define PNG_LIBPNG_VER_RELEASE 22
+#define PNG_LIBPNG_VER_RELEASE 24

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

-#define PNG_LIBPNG_VER_BUILD  0
+#define PNG_LIBPNG_VER_BUILD  03

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

-#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_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.
@@ -354,7 +354,7 @@
 * version 1.0.0 was mis-numbered 100 instead of 10000).  From
 * version 1.0.1 it's    xxyyzz, where x=major, y=minor, z=release
 */
-#define PNG_LIBPNG_VER 10622 /* 1.6.22 */
+#define PNG_LIBPNG_VER 10624 /* 1.6.24 */

 /* Library configuration: these options cannot be changed after
 * the library has been built.
@@ -464,7 +464,7 @@ extern "C" {
 /* This triggers a compiler error in png.c, if png.c and png.h
 * do not agree upon the version number.
 */
-typedef char* png_libpng_version_1_6_22;
+typedef char* png_libpng_version_1_6_24beta03;

 /* Basic control structions.  Read libpng-manual.txt or libpng.3 for more info.
 *
@@ -2300,8 +2300,10 @@ PNG_EXPORT(171, void, png_set_sCAL_s, (png_const_structrp png_ptr,
 *    except for the IHDR, PLTE, tRNS, IDAT, and IEND chunks (which continue to
 *    be processed by libpng.
 */
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
 PNG_EXPORT(172, void, png_set_keep_unknown_chunks, (png_structrp png_ptr,
    int keep, png_const_bytep chunk_list, int num_chunks));
+#endif /* HANDLE_AS_UNKNOWN */

 /* The "keep" PNG_HANDLE_CHUNK_ parameter for the specified chunk is returned;
 * the result is therefore true (non-zero) if special handling is required,
@@ -2309,7 +2311,7 @@ PNG_EXPORT(172, void, png_set_keep_unknown_chunks, (png_structrp png_ptr,
 */
 PNG_EXPORT(173, int, png_handle_as_unknown, (png_const_structrp png_ptr,
    png_const_bytep chunk_name));
-#endif
+#endif /* SET_UNKNOWN_CHUNKS */

 #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
 PNG_EXPORT(174, void, png_set_unknown_chunks, (png_const_structrp png_ptr,
--- a/pngconf.h
+++ b/pngconf.h
@@ -1,7 +1,7 @@

 /* pngconf.h - machine configurable file for libpng
 *
- * libpng version 1.6.22, May 26, 2016
+ * libpng version 1.6.24beta03, July 4, 2016
 *
 * Copyright (c) 1998-2002,2004,2006-2015 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
--- a/pngerror.c
+++ b/pngerror.c
@@ -44,7 +44,7 @@ png_error,(png_const_structrp png_ptr, png_const_charp error_message),
   if (png_ptr != NULL)
   {
      if ((png_ptr->flags &
-         (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT)) != 0
+         (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT)) != 0)
      {
         if (*error_message == PNG_LITERAL_SHARP)
         {
--- a/pngpread.c
+++ b/pngpread.c
@@ -1,8 +1,8 @@

 /* pngpread.c - read a png file in push mode
 *
- * Last changed in libpng 1.6.18 [July 23, 2015]
- * Copyright (c) 1998-2002,2004,2006-2015 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.23 [June 9, 2016]
+ * Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
@@ -210,12 +210,14 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
          (png_ptr->mode & PNG_HAVE_PLTE) == 0)
         png_error(png_ptr, "Missing PLTE before IDAT");

-      png_ptr->mode |= PNG_HAVE_IDAT;
      png_ptr->process_mode = PNG_READ_IDAT_MODE;

-      if ((png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) == 0)
-         if (png_ptr->push_length == 0)
-            return;
+      if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+         if ((png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) == 0)
+            if (png_ptr->push_length == 0)
+               return;
+
+      png_ptr->mode |= PNG_HAVE_IDAT;

      if ((png_ptr->mode & PNG_AFTER_IDAT) != 0)
         png_benign_error(png_ptr, "Too many IDATs found");
@@ -499,7 +501,10 @@ png_push_save_buffer(png_structrp png_ptr)
         png_error(png_ptr, "Insufficient memory for save_buffer");
      }

-      memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size);
+      if (old_buffer)
+         memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size);
+      else if (png_ptr->save_buffer_size)
+         png_error(png_ptr, "save_buffer error");
      png_free(png_ptr, old_buffer);
      png_ptr->save_buffer_max = new_max;
   }
--- a/pngpriv.h
+++ b/pngpriv.h
@@ -1915,8 +1915,6 @@ PNG_INTERNAL_FUNCTION(void, PNG_FILTER_OPTIMIZATIONS, (png_structp png_ptr,
    */
 PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_neon,
   (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
-PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_sse2,
-   (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
 #endif

 PNG_INTERNAL_FUNCTION(png_uint_32, png_check_keyword, (png_structrp png_ptr,
--- a/pngread.c
+++ b/pngread.c
@@ -1,8 +1,8 @@

 /* pngread.c - read a PNG file
 *
- * Last changed in libpng 1.6.17 [March 26, 2015]
- * Copyright (c) 1998-2002,2004,2006-2015 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.24 [(PENDING RELEASE)]
+ * Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
@@ -127,7 +127,10 @@ png_read_info(png_structrp png_ptr, png_inforp info_ptr)
      }

      else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+      {
+         png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
         png_ptr->mode |= PNG_AFTER_IDAT;
+      }

      /* This should be a binary subdivision search or a hash for
       * matching the chunk name rather than a linear search.
@@ -785,6 +788,9 @@ png_read_end(png_structrp png_ptr, png_inforp info_ptr)
      png_uint_32 length = png_read_chunk_header(png_ptr);
      png_uint_32 chunk_name = png_ptr->chunk_name;

+      if (chunk_name != png_IDAT)
+         png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
+
      if (chunk_name == png_IEND)
         png_handle_IEND(png_ptr, info_ptr, length);

@@ -799,9 +805,9 @@ png_read_end(png_structrp png_ptr, png_inforp info_ptr)
      {
         if (chunk_name == png_IDAT)
         {
-            if ((length > 0) ||
-                (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) != 0)
-               png_benign_error(png_ptr, "Too many IDATs found");
+            if ((length > 0 && !(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED))
+                || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) != 0)
+               png_benign_error(png_ptr, ".Too many IDATs found");
         }
         png_handle_unknown(png_ptr, info_ptr, length, keep);
         if (chunk_name == png_PLTE)
@@ -812,10 +818,14 @@ png_read_end(png_structrp png_ptr, png_inforp info_ptr)
      else if (chunk_name == png_IDAT)
      {
         /* Zero length IDATs are legal after the last IDAT has been
-          * read, but not after other chunks have been read.
+          * read, but not after other chunks have been read.  1.6 does not
+          * always read all the deflate data; specifically it cannot be relied
+          * upon to read the Adler32 at the end.  If it doesn't ignore IDAT
+          * chunks which are longer than zero as well:
          */
-         if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) != 0)
-            png_benign_error(png_ptr, "Too many IDATs found");
+         if ((length > 0 && !(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED))
+             || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) != 0)
+            png_benign_error(png_ptr, "..Too many IDATs found");

         png_crc_finish(png_ptr, length);
      }
@@ -4077,6 +4087,12 @@ png_image_finish_read(png_imagep image, png_const_colorp background,
       */
      const unsigned int channels = PNG_IMAGE_PIXEL_CHANNELS(image->format);

+      /* The following checks just the 'row_stride' calculation to ensure it
+       * fits in a signed 32-bit value.  Because channels/components can be
+       * either 1 or 2 bytes in size the length of a row can still overflow 32
+       * bits; this is just to verify that the 'row_stride' argument can be
+       * represented.
+       */
      if (image->width <= 0x7FFFFFFFU/channels) /* no overflow */
      {
         png_uint_32 check;
@@ -4091,13 +4107,30 @@ png_image_finish_read(png_imagep image, png_const_colorp background,
         else
            check = row_stride;

+         /* This verifies 'check', the absolute value of the actual stride
+          * passed in and detects overflow in the application calculation (i.e.
+          * if the app did actually pass in a non-zero 'row_stride'.
+          */
         if (image->opaque != NULL && buffer != NULL && check >= png_row_stride)
         {
            /* Now check for overflow of the image buffer calculation; this
             * limits the whole image size to 32 bits for API compatibility with
             * the current, 32-bit, PNG_IMAGE_BUFFER_SIZE macro.
+             *
+             * The PNG_IMAGE_BUFFER_SIZE macro is:
+             *
+             *    (PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)*height*(row_stride))
+             *
+             * And the component size is always 1 or 2, so make sure that the
+             * number of *bytes* that the application is saying are available
+             * does actually fit into a 32-bit number.
+             *
+             * NOTE: this will be changed in 1.7 because PNG_IMAGE_BUFFER_SIZE
+             * will be changed to use png_alloc_size_t; bigger images can be
+             * accomodated on 64-bit systems.
             */
-            if (image->height <= 0xFFFFFFFF/png_row_stride)
+            if (image->height <=
+                0xFFFFFFFFU/PNG_IMAGE_PIXEL_COMPONENT_SIZE(image->format)/check)
            {
               if ((image->format & PNG_FORMAT_FLAG_COLORMAP) == 0 ||
                  (image->colormap_entries > 0 && colormap != NULL))
--- a/pngrutil.c
+++ b/pngrutil.c
@@ -1512,12 +1512,12 @@ png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
                                    png_crc_finish(png_ptr, length);
                                    finished = 1;

-#                                   ifdef PNG_sRGB_SUPPORTED
+# if defined(PNG_sRGB_SUPPORTED) && PNG_sRGB_PROFILE_CHECKS >= 0
                                    /* Check for a match against sRGB */
                                    png_icc_set_sRGB(png_ptr,
                                       &png_ptr->colorspace, profile,
                                       png_ptr->zstream.adler);
-#                                   endif
+# endif

                                    /* Steal the profile for info_ptr. */
                                    if (info_ptr != NULL)
--- a/pngset.c
+++ b/pngset.c
@@ -1,8 +1,8 @@

 /* pngset.c - storage of image information into info struct
 *
- * Last changed in libpng 1.6.21 [January 15, 2016]
- * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.24 [(PENDING RELEASE)]
+ * Copyright (c) 1998-2016 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
@@ -952,12 +952,14 @@ png_set_tRNS(png_structrp png_ptr, png_inforp info_ptr,

       png_free_data(png_ptr, info_ptr, PNG_FREE_TRNS, 0);

-       /* Changed from num_trans to PNG_MAX_PALETTE_LENGTH in version 1.2.1 */
-       png_ptr->trans_alpha = info_ptr->trans_alpha = png_voidcast(png_bytep,
-         png_malloc(png_ptr, PNG_MAX_PALETTE_LENGTH));
-
       if (num_trans > 0 && num_trans <= PNG_MAX_PALETTE_LENGTH)
+       {
+         /* Changed from num_trans to PNG_MAX_PALETTE_LENGTH in version 1.2.1 */
+          info_ptr->trans_alpha = png_voidcast(png_bytep,
+             png_malloc(png_ptr, PNG_MAX_PALETTE_LENGTH));
          memcpy(info_ptr->trans_alpha, trans_alpha, (png_size_t)num_trans);
+       }
+       png_ptr->trans_alpha = info_ptr->trans_alpha;
   }

   if (trans_color != NULL)
@@ -1660,7 +1662,9 @@ png_set_check_for_invalid_index(png_structrp png_ptr, int allowed)
 png_uint_32 /* PRIVATE */
 png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key)
 {
+#ifdef PNG_WARNINGS_SUPPORTED
   png_const_charp orig_key = key;
+#endif
   png_uint_32 key_len = 0;
   int bad_character = 0;
   int space = 1;
@@ -1723,7 +1727,9 @@ png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key)

      png_formatted_warning(png_ptr, p, "keyword \"@1\": bad character '0x@2'");
   }
-#endif /* WARNINGS */
+#else /* !WARNINGS */
+   PNG_UNUSED(png_ptr)
+#endif /* !WARNINGS */

   return key_len;
 }
--- a/pngstruct.h
+++ b/pngstruct.h
@@ -1,8 +1,8 @@

 /* pngstruct.h - header file for PNG reference library
 *
- * Last changed in libpng 1.6.18 [July 23, 2015]
- * Copyright (c) 1998-2002,2004,2006-2015 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.24 [(PENDING RELEASE)]
+ * Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
@@ -249,7 +249,7 @@ struct png_struct_def
   png_byte filter;           /* file filter type (always 0) */
   png_byte interlaced;       /* PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */
   png_byte pass;             /* current interlace pass (0 - 6) */
-   png_byte do_filter;        /* row filter flags (see PNG_FILTER_ below ) */
+   png_byte do_filter;        /* row filter flags (see PNG_FILTER_ in png.h ) */
   png_byte color_type;       /* color type of file */
   png_byte bit_depth;        /* bit depth of file */
   png_byte usr_bit_depth;    /* bit depth of users row: write only */
--- a/pngtest.c
+++ b/pngtest.c
@@ -2079,4 +2079,4 @@ main(void)
 #endif

 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef png_libpng_version_1_6_22 Your_png_h_is_not_version_1_6_22;
+typedef png_libpng_version_1_6_24beta03 Your_png_h_is_not_version_1_6_24beta03;
--- a/pngwutil.c
+++ b/pngwutil.c
@@ -1,7 +1,7 @@

 /* pngwutil.c - utilities to write a PNG file
 *
- * Last changed in libpng 1.6.22 [May 26, 2016]
+ * Last changed in libpng 1.6.24 [(PENDING RELEASE)]
 * Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -2262,14 +2262,22 @@ png_setup_sub_row(png_structrp png_ptr, const png_uint_32 bpp,
        i++, rp++, dp++)
   {
      v = *dp = *rp;
+#ifdef PNG_USE_ABS
+      sum += 128 - abs(v - 128);
+#else
      sum += (v < 128) ? v : 256 - v;
+#endif
   }

   for (lp = png_ptr->row_buf + 1; i < row_bytes;
      i++, rp++, lp++, dp++)
   {
      v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
+#ifdef PNG_USE_ABS
+      sum += 128 - abs(v - 128);
+#else
      sum += (v < 128) ? v : 256 - v;
+#endif

      if (sum > lmins)  /* We are already worse, don't continue. */
        break;
@@ -2294,7 +2302,11 @@ png_setup_up_row(png_structrp png_ptr, const png_size_t row_bytes,
       i++, rp++, pp++, dp++)
   {
      v = *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
+#ifdef PNG_USE_ABS
+      sum += 128 - abs(v - 128);
+#else
      sum += (v < 128) ? v : 256 - v;
+#endif

      if (sum > lmins)  /* We are already worse, don't continue. */
        break;
@@ -2319,7 +2331,11 @@ png_setup_avg_row(png_structrp png_ptr, const png_uint_32 bpp,
   {
      v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);

+#ifdef PNG_USE_ABS
+      sum += 128 - abs(v - 128);
+#else
      sum += (v < 128) ? v : 256 - v;
+#endif
   }

   for (lp = png_ptr->row_buf + 1; i < row_bytes; i++)
@@ -2327,7 +2343,11 @@ png_setup_avg_row(png_structrp png_ptr, const png_uint_32 bpp,
      v = *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))
          & 0xff);

+#ifdef PNG_USE_ABS
+      sum += 128 - abs(v - 128);
+#else
      sum += (v < 128) ? v : 256 - v;
+#endif

      if (sum > lmins)  /* We are already worse, don't continue. */
        break;
@@ -2352,7 +2372,11 @@ png_setup_paeth_row(png_structrp png_ptr, const png_uint_32 bpp,
   {
      v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);

+#ifdef PNG_USE_ABS
+      sum += 128 - abs(v - 128);
+#else
      sum += (v < 128) ? v : 256 - v;
+#endif
   }

   for (lp = png_ptr->row_buf + 1, cp = png_ptr->prev_row + 1; i < row_bytes;
@@ -2381,7 +2405,11 @@ png_setup_paeth_row(png_structrp png_ptr, const png_uint_32 bpp,

      v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);

+#ifdef PNG_USE_ABS
+      sum += 128 - abs(v - 128);
+#else
      sum += (v < 128) ? v : 256 - v;
+#endif

      if (sum > lmins)  /* We are already worse, don't continue. */
        break;
@@ -2397,7 +2425,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
 #ifndef PNG_WRITE_FILTER_SUPPORTED
   png_write_filtered_row(png_ptr, png_ptr->row_buf, row_info->rowbytes+1);
 #else
-   png_byte filter_to_do = png_ptr->do_filter;
+   unsigned int filter_to_do = png_ptr->do_filter;
   png_bytep row_buf;
   png_bytep best_row;
   png_uint_32 bpp;
@@ -2443,32 +2471,33 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
    */
   best_row = png_ptr->row_buf;

-
-   if ((filter_to_do & PNG_FILTER_NONE) != 0 && filter_to_do != PNG_FILTER_NONE)
+   if (PNG_SIZE_MAX/128 <= row_bytes)
   {
+      /* Overflow can occur in the calculation, just select the lowest set
+       * filter.
+       */
+      filter_to_do &= 0U-filter_to_do;
+   }
+   else if ((filter_to_do & PNG_FILTER_NONE) != 0 &&
+         filter_to_do != PNG_FILTER_NONE)
+   {
+      /* Overflow not possible and multiple filters in the list, including the
+       * 'none' filter.
+       */
      png_bytep rp;
      png_size_t sum = 0;
      png_size_t i;
      int v;

-      if (PNG_SIZE_MAX/128 <= row_bytes)
-      {
-         for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)
-         {
-            /* Check for overflow */
-            if (sum > PNG_SIZE_MAX/128 - 256)
-               break;
-
-            v = *rp;
-            sum += (v < 128) ? v : 256 - v;
-         }
-      }
-      else /* Overflow is not possible */
      {
         for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)
         {
            v = *rp;
+#ifdef PNG_USE_ABS
+            sum += 128 - abs(v - 128);
+#else
            sum += (v < 128) ? v : 256 - v;
+#endif
         }
      }

@@ -2479,7 +2508,12 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
   if (filter_to_do == PNG_FILTER_SUB)
   /* It's the only filter so no testing is needed */
   {
-      (void) png_setup_sub_row(png_ptr, bpp, row_bytes, mins);
+      /* Passing PNG_SIZE_MAX here and below prevents the 'setup' function
+       * breaking out of the loop when lmins is exceeded. Optimizing
+       * compilers should notice that we don't use the returned sum, and
+       * therefore 'setup' should refrain from calculating and returning "sum".
+       */
+      (void) png_setup_sub_row(png_ptr, bpp, row_bytes, PNG_SIZE_MAX);
      best_row = png_ptr->try_row;
   }

@@ -2505,7 +2539,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
   /* Up filter */
   if (filter_to_do == PNG_FILTER_UP)
   {
-      (void) png_setup_up_row(png_ptr, row_bytes, mins);
+      (void) png_setup_up_row(png_ptr, row_bytes, PNG_SIZE_MAX);
      best_row = png_ptr->try_row;
   }

@@ -2531,7 +2565,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
   /* Avg filter */
   if (filter_to_do == PNG_FILTER_AVG)
   {
-      (void) png_setup_avg_row(png_ptr, bpp, row_bytes, mins);
+      (void) png_setup_avg_row(png_ptr, bpp, row_bytes, PNG_SIZE_MAX);
      best_row = png_ptr->try_row;
   }

@@ -2557,7 +2591,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
   /* Paeth filter */
   if ((filter_to_do == PNG_FILTER_PAETH) != 0)
   {
-      (void) png_setup_paeth_row(png_ptr, bpp, row_bytes, mins);
+      (void) png_setup_paeth_row(png_ptr, bpp, row_bytes, PNG_SIZE_MAX);
      best_row = png_ptr->try_row;
   }

--- a/projects/vstudio/README.txt
+++ b/projects/vstudio/README.txt
@@ -1,7 +1,7 @@

 VisualStudio instructions

-libpng version 1.6.22 - May 26, 2016
+libpng version 1.6.24beta03 - July 4, 2016

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

@@ -93,3 +93,5 @@ as follows:
    DLL               /MD         /MDd
    Static Library    /MD         /MDd

+Also, be sure to build libpng, zlib, and your project all for the same
+platform (e.g., 32-bit or 64-bit).
--- a/projects/vstudio/libpng/libpng.vcxproj
+++ b/projects/vstudio/libpng/libpng.vcxproj
@@ -84,7 +84,7 @@
  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
    <ClCompile>
      <PrecompiledHeader>Use</PrecompiledHeader>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
      <MinimalRebuild>false</MinimalRebuild>
      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
      <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
@@ -97,9 +97,9 @@
      <BrowseInformation>true</BrowseInformation>
      <CompileAs>CompileAsC</CompileAs>
      <StringPooling>true</StringPooling>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
      <AdditionalIncludeDirectories>$(ZLibSrcDir);%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
      <Optimization>Disabled</Optimization>
      <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
    </ClCompile>
@@ -114,7 +114,7 @@
  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
    <ClCompile>
      <PrecompiledHeader>Use</PrecompiledHeader>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
      <MinimalRebuild>false</MinimalRebuild>
      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
      <Optimization>Disabled</Optimization>
@@ -128,9 +128,9 @@
      <BrowseInformation>true</BrowseInformation>
      <CompileAs>CompileAsC</CompileAs>
      <StringPooling>true</StringPooling>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
      <AdditionalIncludeDirectories>$(ZLibSrcDir);%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
      <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
    </ClCompile>
    <Link>
@@ -140,7 +140,7 @@
  </ItemDefinitionGroup>
  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
    <ClCompile>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
      <PrecompiledHeader>Use</PrecompiledHeader>
      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
      <FunctionLevelLinking>true</FunctionLevelLinking>
@@ -153,9 +153,9 @@
      <CompileAs>CompileAsC</CompileAs>
      <StringPooling>true</StringPooling>
      <MinimalRebuild>false</MinimalRebuild>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
      <AdditionalIncludeDirectories>$(ZLibSrcDir);%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
      <Optimization>Full</Optimization>
    </ClCompile>
    <Link>
@@ -170,7 +170,7 @@
  </ItemDefinitionGroup>
  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
    <ClCompile>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
      <PrecompiledHeader>Use</PrecompiledHeader>
      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
      <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
@@ -184,9 +184,9 @@
      <CompileAs>CompileAsC</CompileAs>
      <StringPooling>true</StringPooling>
      <MinimalRebuild>false</MinimalRebuild>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
      <AdditionalIncludeDirectories>$(ZLibSrcDir);%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
      <Optimization>Full</Optimization>
      <WholeProgramOptimization>true</WholeProgramOptimization>
    </ClCompile>
--- a/projects/vstudio/pnglibconf/pnglibconf.vcxproj
+++ b/projects/vstudio/pnglibconf/pnglibconf.vcxproj
@@ -30,7 +30,7 @@
  </PropertyGroup>
  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
    <ClCompile>
-      <WarningLevel>Level3</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
      <Optimization>MaxSpeed</Optimization>
      <FunctionLevelLinking>true</FunctionLevelLinking>
      <IntrinsicFunctions>true</IntrinsicFunctions>
--- a/projects/vstudio/pngstest/pngstest.vcxproj
+++ b/projects/vstudio/pngstest/pngstest.vcxproj
@@ -76,16 +76,16 @@
  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
    <ClCompile>
      <PrecompiledHeader>NotUsing</PrecompiledHeader>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
      <MinimalRebuild>false</MinimalRebuild>
      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
      <Optimization>Disabled</Optimization>
      <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;PNG_USE_DLL;%(PreprocessorDefinitions)</PreprocessorDefinitions>
      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
      <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
      <IntrinsicFunctions>true</IntrinsicFunctions>
      <StringPooling>true</StringPooling>
      <FunctionLevelLinking>false</FunctionLevelLinking>
@@ -109,7 +109,7 @@
  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
    <ClCompile>
      <PrecompiledHeader>NotUsing</PrecompiledHeader>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
      <MinimalRebuild>false</MinimalRebuild>
      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
      <Optimization>Disabled</Optimization>
@@ -117,9 +117,9 @@
      <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
      <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
      <IntrinsicFunctions>true</IntrinsicFunctions>
      <StringPooling>true</StringPooling>
      <FunctionLevelLinking>false</FunctionLevelLinking>
@@ -141,7 +141,7 @@
  </ItemDefinitionGroup>
  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
    <ClCompile>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
      <PrecompiledHeader>NotUsing</PrecompiledHeader>
      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
      <Optimization>Full</Optimization>
@@ -149,9 +149,9 @@
      <IntrinsicFunctions>true</IntrinsicFunctions>
      <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;PNG_USE_DLL;%(PreprocessorDefinitions)</PreprocessorDefinitions>
      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
      <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
      <StringPooling>true</StringPooling>
      <MinimalRebuild>false</MinimalRebuild>
      <BrowseInformation>true</BrowseInformation>
@@ -176,7 +176,7 @@
  </ItemDefinitionGroup>
  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
    <ClCompile>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
      <PrecompiledHeader>NotUsing</PrecompiledHeader>
      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
      <Optimization>Full</Optimization>
@@ -185,9 +185,9 @@
      <IntrinsicFunctions>true</IntrinsicFunctions>
      <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
      <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
      <StringPooling>true</StringPooling>
      <MinimalRebuild>false</MinimalRebuild>
      <BrowseInformation>true</BrowseInformation>
--- a/projects/vstudio/pngtest/pngtest.vcxproj
+++ b/projects/vstudio/pngtest/pngtest.vcxproj
@@ -76,16 +76,16 @@
  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
    <ClCompile>
      <PrecompiledHeader>NotUsing</PrecompiledHeader>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
      <MinimalRebuild>false</MinimalRebuild>
      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
      <Optimization>Disabled</Optimization>
      <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
      <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
      <IntrinsicFunctions>true</IntrinsicFunctions>
      <StringPooling>true</StringPooling>
      <FunctionLevelLinking>false</FunctionLevelLinking>
@@ -109,7 +109,7 @@
  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
    <ClCompile>
      <PrecompiledHeader>NotUsing</PrecompiledHeader>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
      <MinimalRebuild>false</MinimalRebuild>
      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
      <Optimization>Disabled</Optimization>
@@ -117,9 +117,9 @@
      <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
      <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
      <IntrinsicFunctions>true</IntrinsicFunctions>
      <StringPooling>true</StringPooling>
      <FunctionLevelLinking>false</FunctionLevelLinking>
@@ -141,7 +141,7 @@
  </ItemDefinitionGroup>
  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
    <ClCompile>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
      <PrecompiledHeader>NotUsing</PrecompiledHeader>
      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
      <Optimization>Full</Optimization>
@@ -149,9 +149,9 @@
      <IntrinsicFunctions>true</IntrinsicFunctions>
      <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
      <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
      <StringPooling>true</StringPooling>
      <MinimalRebuild>false</MinimalRebuild>
      <BrowseInformation>true</BrowseInformation>
@@ -176,7 +176,7 @@
  </ItemDefinitionGroup>
  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
    <ClCompile>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
      <PrecompiledHeader>NotUsing</PrecompiledHeader>
      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
      <Optimization>Full</Optimization>
@@ -185,9 +185,9 @@
      <IntrinsicFunctions>true</IntrinsicFunctions>
      <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
      <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
      <StringPooling>true</StringPooling>
      <MinimalRebuild>false</MinimalRebuild>
      <BrowseInformation>true</BrowseInformation>
--- a/projects/vstudio/pngunknown/pngunknown.vcxproj
+++ b/projects/vstudio/pngunknown/pngunknown.vcxproj
@@ -76,16 +76,16 @@
  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
    <ClCompile>
      <PrecompiledHeader>NotUsing</PrecompiledHeader>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
      <MinimalRebuild>false</MinimalRebuild>
      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
      <Optimization>Disabled</Optimization>
      <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;PNG_USE_DLL;%(PreprocessorDefinitions)</PreprocessorDefinitions>
      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
      <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
      <IntrinsicFunctions>true</IntrinsicFunctions>
      <StringPooling>true</StringPooling>
      <FunctionLevelLinking>false</FunctionLevelLinking>
@@ -109,7 +109,7 @@
  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
    <ClCompile>
      <PrecompiledHeader>NotUsing</PrecompiledHeader>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
      <MinimalRebuild>false</MinimalRebuild>
      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
      <Optimization>Disabled</Optimization>
@@ -117,9 +117,9 @@
      <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
      <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
      <IntrinsicFunctions>true</IntrinsicFunctions>
      <StringPooling>true</StringPooling>
      <FunctionLevelLinking>false</FunctionLevelLinking>
@@ -141,7 +141,7 @@
  </ItemDefinitionGroup>
  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
    <ClCompile>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
      <PrecompiledHeader>NotUsing</PrecompiledHeader>
      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
      <Optimization>Full</Optimization>
@@ -149,9 +149,9 @@
      <IntrinsicFunctions>true</IntrinsicFunctions>
      <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;PNG_USE_DLL;%(PreprocessorDefinitions)</PreprocessorDefinitions>
      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
      <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
      <StringPooling>true</StringPooling>
      <MinimalRebuild>false</MinimalRebuild>
      <BrowseInformation>true</BrowseInformation>
@@ -176,7 +176,7 @@
  </ItemDefinitionGroup>
  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
    <ClCompile>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
      <PrecompiledHeader>NotUsing</PrecompiledHeader>
      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
      <Optimization>Full</Optimization>
@@ -185,9 +185,9 @@
      <IntrinsicFunctions>true</IntrinsicFunctions>
      <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
      <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
      <StringPooling>true</StringPooling>
      <MinimalRebuild>false</MinimalRebuild>
      <BrowseInformation>true</BrowseInformation>
--- a/projects/vstudio/pngvalid/pngvalid.vcxproj
+++ b/projects/vstudio/pngvalid/pngvalid.vcxproj
@@ -76,16 +76,16 @@
  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
    <ClCompile>
      <PrecompiledHeader>NotUsing</PrecompiledHeader>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
      <MinimalRebuild>false</MinimalRebuild>
      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
      <Optimization>Disabled</Optimization>
      <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;PNG_USE_DLL;%(PreprocessorDefinitions)</PreprocessorDefinitions>
      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
      <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
      <IntrinsicFunctions>true</IntrinsicFunctions>
      <StringPooling>true</StringPooling>
      <FunctionLevelLinking>false</FunctionLevelLinking>
@@ -109,7 +109,7 @@
  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
    <ClCompile>
      <PrecompiledHeader>NotUsing</PrecompiledHeader>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
      <MinimalRebuild>false</MinimalRebuild>
      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
      <Optimization>Disabled</Optimization>
@@ -117,9 +117,9 @@
      <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
      <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
      <IntrinsicFunctions>true</IntrinsicFunctions>
      <StringPooling>true</StringPooling>
      <FunctionLevelLinking>false</FunctionLevelLinking>
@@ -141,7 +141,7 @@
  </ItemDefinitionGroup>
  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
    <ClCompile>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
      <PrecompiledHeader>NotUsing</PrecompiledHeader>
      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
      <Optimization>Full</Optimization>
@@ -149,9 +149,9 @@
      <IntrinsicFunctions>true</IntrinsicFunctions>
      <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;PNG_USE_DLL;%(PreprocessorDefinitions)</PreprocessorDefinitions>
      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
      <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
      <StringPooling>true</StringPooling>
      <MinimalRebuild>false</MinimalRebuild>
      <BrowseInformation>true</BrowseInformation>
@@ -176,7 +176,7 @@
  </ItemDefinitionGroup>
  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
    <ClCompile>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
      <PrecompiledHeader>NotUsing</PrecompiledHeader>
      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
      <Optimization>Full</Optimization>
@@ -185,9 +185,9 @@
      <IntrinsicFunctions>true</IntrinsicFunctions>
      <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
      <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
      <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
      <StringPooling>true</StringPooling>
      <MinimalRebuild>false</MinimalRebuild>
      <BrowseInformation>true</BrowseInformation>
--- a/projects/vstudio/zlib.props
+++ b/projects/vstudio/zlib.props
@@ -2,7 +2,7 @@
 <!--
 * zlib.props - location of zlib source
 *
- * libpng version 1.6.22 - May 26, 2016
+ * libpng version 1.6.24beta03 - July 4, 2016
 *
 * Copyright (c) 1998-2011 Glenn Randers-Pehrson
 *
@@ -41,5 +41,18 @@
         test it:
     -->
    <WindowsSDKDesktopARMSupport>true</WindowsSDKDesktopARMSupport>
+
+    <!-- The following lines provide a global (solution level) control of the
+         warnings issued by the compiler, these are used in the individual
+         project files (*/*.vcxproj) with, for zlib, some extra disables.
+
+         Different versions of Visual Studio may require different settings,
+         these settings work with Visual Studio 2013.  Just set
+         TreatWarningAsError to false to check the build without failing on
+         errors.
+     -->
+   <WarningLevel>EnableAllWarnings</WarningLevel>
+   <TreatWarningAsError>true</TreatWarningAsError>
+   <DisableSpecificWarnings>4255;4668;4710;4711;4746;4820;4996</DisableSpecificWarnings>
  </PropertyGroup>
 </Project>
--- a/projects/vstudio/zlib/zlib.vcxproj
+++ b/projects/vstudio/zlib/zlib.vcxproj
@@ -88,11 +88,13 @@
    <ClCompile>
      <PreprocessorDefinitions>WIN32;_DEBUG;_WINDOWS;Z_SOLO;%(PreprocessorDefinitions)</PreprocessorDefinitions>
      <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
-      <WarningLevel>TurnOffAllWarnings</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
      <Optimization>Disabled</Optimization>
      <BrowseInformation>true</BrowseInformation>
      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings);4127;4131;4242;4244</DisableSpecificWarnings>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
    </ClCompile>
    <Link>
      <TargetMachine>MachineX86</TargetMachine>
@@ -103,11 +105,13 @@
  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
    <ClCompile>
      <PreprocessorDefinitions>WIN32;_DEBUG;_WINDOWS;Z_SOLO;%(PreprocessorDefinitions)</PreprocessorDefinitions>
-      <WarningLevel>TurnOffAllWarnings</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
      <Optimization>Disabled</Optimization>
      <BrowseInformation>true</BrowseInformation>
      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings);4127;4131;4242;4244</DisableSpecificWarnings>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
      <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
    </ClCompile>
    <Link>
@@ -118,7 +122,7 @@
  </ItemDefinitionGroup>
  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
    <ClCompile>
-      <WarningLevel>Level3</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
      <Optimization>Full</Optimization>
      <IntrinsicFunctions>true</IntrinsicFunctions>
@@ -126,7 +130,8 @@
      <BufferSecurityCheck>false</BufferSecurityCheck>
      <BrowseInformation>true</BrowseInformation>
      <FunctionLevelLinking>true</FunctionLevelLinking>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings);4127;4131;4242;4244</DisableSpecificWarnings>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
      <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
      <PreprocessorDefinitions>WIN32;NDEBUG;_WINDOWS;Z_SOLO;%(PreprocessorDefinitions)</PreprocessorDefinitions>
    </ClCompile>
@@ -141,7 +146,7 @@
  </ItemDefinitionGroup>
  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
    <ClCompile>
-      <WarningLevel>Level3</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
      <Optimization>Full</Optimization>
      <IntrinsicFunctions>true</IntrinsicFunctions>
@@ -149,7 +154,8 @@
      <BufferSecurityCheck>false</BufferSecurityCheck>
      <BrowseInformation>true</BrowseInformation>
      <FunctionLevelLinking>true</FunctionLevelLinking>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings);4127;4131;4242;4244</DisableSpecificWarnings>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
      <PreprocessorDefinitions>WIN32;NDEBUG;_WINDOWS;Z_SOLO;%(PreprocessorDefinitions)</PreprocessorDefinitions>
    </ClCompile>
    <Link>
--- a/scripts/README.txt
+++ b/scripts/README.txt
@@ -1,9 +1,9 @@

-Makefiles for  libpng version 1.6.22 - May 26, 2016
+Makefiles for  libpng version 1.6.24beta03 - July 4, 2016

 pnglibconf.h.prebuilt       =>  Stores configuration settings
 makefile.linux    =>  Linux/ELF makefile
-                       (gcc, creates libpng16.so.16.1.6.22)
+                       (gcc, creates libpng16.so.16.1.6.24beta03)
 makefile.gcc      =>  Generic makefile (gcc, creates static libpng.a)
 makefile.knr      =>  Archaic UNIX Makefile that converts files with
                       ansi2knr (Requires ansi2knr.c from
@@ -33,12 +33,12 @@ pnglibconf.h.prebuilt       =>  Stores configuration settings
 makefile.os2      =>  OS/2 Makefile (gcc and emx, requires libpng.def)
 makefile.sco      =>  For SCO OSr5  ELF and Unixware 7 with Native cc
 makefile.sggcc    =>  Silicon Graphics (gcc,
-                       creates libpng16.so.16.1.6.22)
+                       creates libpng16.so.16.1.6.24beta03)
 makefile.sgi      =>  Silicon Graphics IRIX makefile (cc, creates static lib)
 makefile.solaris  =>  Solaris 2.X makefile (gcc,
-                       creates libpng16.so.16.1.6.22)
+                       creates libpng16.so.16.1.6.24beta03)
 makefile.so9      =>  Solaris 9 makefile (gcc,
-                       creates libpng16.so.16.1.6.22)
+                       creates libpng16.so.16.1.6.24beta03)
 makefile.std      =>  Generic UNIX makefile (cc, creates static libpng.a)
 makefile.sunos    =>  Sun makefile
 makefile.32sunu   =>  Sun Ultra 32-bit makefile
--- a/scripts/def.c
+++ b/scripts/def.c
@@ -21,7 +21,7 @@ PNG_DFN "OS2 DESCRIPTION "PNG image compression library""
 PNG_DFN "OS2 CODE PRELOAD MOVEABLE DISCARDABLE"
 PNG_DFN ""
 PNG_DFN "EXPORTS"
-PNG_DFN ";Version 1.6.22"
+PNG_DFN ";Version 1.6.24beta03"

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

 # Modeled after libxml-config.

-version=1.6.22
+version=1.6.24beta03
 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: 1.6.22
+Version: 1.6.24beta03
 Libs: -L${libdir} -lpng16
 Cflags: -I${includedir}
--- a/scripts/makefile.cegcc
+++ b/scripts/makefile.cegcc
@@ -23,7 +23,7 @@

 VERMAJ = 1
 VERMIN = 6
-VERMIC = 22
+VERMIC = 24
 VER = $(VERMAJ).$(VERMIN).$(VERMIC)
 NAME = libpng
 PACKAGE = $(NAME)-$(VER)
--- a/scripts/makefile.linux
+++ b/scripts/makefile.linux
@@ -10,7 +10,7 @@
 # Library name:
 LIBNAME = libpng16
 PNGMAJ = 16
-RELEASE = 22
+RELEASE = 24

 # Shared library names:
 LIBSO=$(LIBNAME).so
--- a/scripts/makefile.msys
+++ b/scripts/makefile.msys
@@ -18,7 +18,7 @@ exec_prefix=$(prefix)
 # Library name:
 LIBNAME = libpng16
 PNGMAJ = 16
-RELEASE = 22
+RELEASE = 24

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

 LIB=	png16
 SHLIB_MAJOR=	0
-SHLIB_MINOR=	1.6.22
+SHLIB_MINOR=	1.6.24beta03
 SRCS=	png.c pngset.c pngget.c pngrutil.c pngtrans.c pngwutil.c \
 	pngread.c pngrio.c pngwio.c pngwrite.c pngrtran.c \
 	pngwtran.c pngmem.c pngerror.c pngpread.c
--- a/scripts/makefile.netbsd
+++ b/scripts/makefile.netbsd
@@ -17,7 +17,7 @@ INCSDIR=${LOCALBASE}/include

 LIB=	png
 SHLIB_MAJOR=	16
-SHLIB_MINOR=	1.6.22
+SHLIB_MINOR=	1.6.24beta03
 SRCS=	png.c pngset.c pngget.c pngrutil.c pngtrans.c pngwutil.c \
 	pngread.c pngrio.c pngwio.c pngwrite.c pngrtran.c \
 	pngwtran.c pngmem.c pngerror.c pngpread.c
--- a/scripts/makefile.openbsd
+++ b/scripts/makefile.openbsd
@@ -11,7 +11,7 @@ LIBDIR=	${PREFIX}/lib
 MANDIR= ${PREFIX}/man/cat

 SHLIB_MAJOR=	16
-SHLIB_MINOR=	1.6.22
+SHLIB_MINOR=	1.6.24beta03

 LIB=	png
 SRCS=	png.c pngerror.c pngget.c pngmem.c pngpread.c \
--- a/scripts/pnglibconf.dfa
+++ b/scripts/pnglibconf.dfa
@@ -552,6 +552,7 @@ option WRITE_ANCILLARY_CHUNKS requires WRITE

 # These options disable *all* the text chunks if turned off

+option TEXT disabled
 option READ_TEXT requires READ_ANCILLARY_CHUNKS enables TEXT
 option WRITE_TEXT requires WRITE_ANCILLARY_CHUNKS enables TEXT

--- a/scripts/pnglibconf.h.prebuilt
+++ b/scripts/pnglibconf.h.prebuilt
@@ -1,8 +1,8 @@
-/* libpng 1.6.22 STANDARD API DEFINITION */
+/* libpng 1.6.24beta03 STANDARD API DEFINITION */

 /* pnglibconf.h - library build configuration */

-/* Libpng version 1.6.22 - May 26, 2016 */
+/* Libpng version 1.6.24beta03 - July 4, 2016 */

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

--- a/scripts/symbols.def
+++ b/scripts/symbols.def
@@ -1,4 +1,4 @@
-;Version 1.6.22
+;Version 1.6.24beta03
 ;--------------------------------------------------------------
 ; LIBPNG symbol list as a Win32 DEF file
 ; Contains all the symbols that can be exported from libpng
Author	SHA1	Message	Date
Glenn Randers-Pehrson	66f796e74c	[libpng16] Imported from libpng-1.6.24beta03.tar	2016-07-04 09:55:12 -05:00
Glenn Randers-Pehrson	a3eac818d5	[libpng16] Update CHANGES and ANNOUNCE	2016-07-03 18:10:21 -05:00
John Bowler	cfc19ff1b6	pngcp bug fixes The fixed size buffer for the file name being processed could have a byte written beyond the end; a bug where the test was updated without changing the size of the buffer. This commit reduces the buffer to the system maximum. png_getrowbytes could, in theory, return 0; probably only if there is a bug in libpng but the code now checks. Signed-off-by: John Bowler <jbowler@acm.org>	2016-07-03 13:49:36 -07:00
Glenn Randers-Pehrson	80495124b2	[libpng16] Don't call png_icc_set_sRGB() when it's not compiled.	2016-07-03 10:28:54 -05:00
Glenn Randers-Pehrson	2c21a4778d	[libpng16] Relocated misplaced #endif in png.c sRGB profile checking.	2016-07-02 21:17:56 -05:00
Glenn Randers-Pehrson	14b8dee96f	Merge branch 'libpng16' of ssh://git.code.sf.net/p/libpng/code into libpng16	2016-07-02 14:32:37 -05:00
Glenn Randers-Pehrson	11c88033d4	[libpng16] Added "Common linking failures" section to INSTALL	2016-07-02 14:29:29 -05:00
Glenn Randers-Pehrson	25bb30c9b8	[libpng16] Added "Common linking failures" section to INSTALL	2016-07-02 12:00:07 -05:00
John Bowler	54feb0ad2a	pngimage: correct #define checking In libpng 1.7 pngimage needs to check PNG_WRITE_PNG_SUPPORTED (new in 1.7), not PNG_WRITE_SUPPORTED because png_write_png can be disabled without disabling PNG_WRITE_SUPPORTED. Copied the approach from 1.6 pngcp.c (so this still works in 1.6 as well.)	2016-07-02 08:03:09 -07:00
Glenn Randers-Pehrson	b733c50bc0	[libpng16] Updated CHANGES and ANNOUNCE	2016-07-01 18:42:07 -05:00
John Bowler	a93744423d	pngcp.c: correct total time output Signed-off-by: John Bowler <jbowler@acm.org>	2016-07-01 11:29:58 -07:00
John Bowler	9957c45073	pngcp: add high resolution timing If PNG_PNGCP_TIMING_SUPPORTED is defined maximal resolution CPU time logging of png_read_png and png_write_png is enabled via the --time command line option. This is not on by default but is enabled by contrib/conftests/pngcp.dfa Signed-off-by: John Bowler <jbowler@acm.org>	2016-07-01 11:29:45 -07:00
John Bowler	0ac91cc657	pngcp: tool to copy PNG files This adds pngcp to the build together with a pngcp.dfa configuration test; the test revealed some configuration bugs which are fixed by corrections to the _SUPPORTED macros. pngcp builds on all tested configurations and a number of bugs have been fixed to make this happen relative to the version in libpng 1.7 contrib/examples. pngcp.dfa will have to be different for 1.7 but pngcp.c should work fine (not yet tested). pngcp itself is still missing a usage message; this is a preliminary version, although since it behaves the same way as 'cp' most unoids shouldn't have a problem using it correctly. Signed-off-by: John Bowler <jbowler@acm.org>	2016-07-01 11:27:43 -07:00
Glenn Randers-Pehrson	d9779744f9	[libpng16] Optimized absolute value calculation in filter selection, similar to code in the PAETH decoder in pngrutil.c. Build with PNG_USE_ABS to use this.	2016-06-29 21:53:57 -05:00
Glenn Randers-Pehrson	ed5a01d922	[libpng16] Update ANNOUNCE	2016-06-23 11:53:31 -05:00
Glenn Randers-Pehrson	d43f93ff93	[libpng16] Bump version to 1.6.24beta03	2016-06-23 11:27:12 -05:00
Glenn Randers-Pehrson	3f2879bf60	[libpng16] Imported from libpng-1.6.24beta02.tar	2016-06-23 11:26:59 -05:00
Glenn Randers-Pehrson	ee1e535298	[libpng16] Bump version to 1.6.24beta03	2016-06-23 11:08:14 -05:00
Glenn Randers-Pehrson	4b4a9583b4	[libpng16] Imported from libpng-1.6.24beta02.tar	2016-06-23 11:08:06 -05:00
John Bowler	da2ba024a5	[libpng16] Update CHANGES and ANNOUNCE	2016-06-23 10:51:44 -05:00
John Bowler	e5d468ea9c	projects/vstudio: enthusiastic warnings The commit removes the three compile warning options from the individual project files into the zlib.props globals (this should probably be renamed in 1.7). It increases the warning level from 4 to All and adds a list of the warnings which need to be turned off. This is semi-documentary; the intent is to tell users of libpng which warnings have been examined and judged non-fixable at present. The warning about structure padding IS fixable, but it is a signficant change (moving structure members around). It is currently partially fixed in 1.7, but only partially. Signed-off-by: John Bowler <jbowler@acm.org>	2016-06-22 17:40:06 -07:00
John Bowler	21d9e6e0fb	SKIP definition in pngstest.c misplaced The SKIP definition needs to come after the png.h include (see all the other .c files in contrib/libtests) because it depends on PNG_LIBPNG_VER. This commit puts it in the correct place. Signed-off-by: John Bowler <jbowler@acm.org>	2016-06-22 17:38:56 -07:00
John Bowler	98af505439	Fix MSVC Level 4 warning MSVC does not like (uInt) = -(unsigned) (i.e. as an initializer), but it is fine with it if the conversion is explicitly invoked by a cast. Signed-off-by: John Bowler <jbowler@acm.org>	2016-06-22 17:37:20 -07:00
John Bowler	1df0ace0b4	Fix MSVC Level 2 warning MSVC doesn't like '-(unsigned)', so replace it by 0U-(unsigned) (in 1.6). Signed-off-by: John Bowler <jbowler@acm.org>	2016-06-22 17:35:49 -07:00
John Bowler	4af267c07b	Merge branch 'libpng16' of ../../libpng into libpng16	2016-06-20 09:23:59 -07:00
Glenn Randers-Pehrson	6c7c5a04b8	[libpng16] More efficient absolute value calculation on SSE2 (Matthieu Darbois).	2016-06-20 08:28:34 -05:00
Glenn Randers-Pehrson	42069e9432	Merge branch 'tryagain' of git://github.com/mattsarett/libpng into libpng16	2016-06-20 08:27:24 -05:00
Matt Sarett	36762ac4b4	More efficient absolute value on SSE2	2016-06-20 09:06:25 -04:00
Glenn Randers-Pehrson	147dc568da	[libpng16] Backed out previous optimization; the compiler should handle that.	2016-06-19 22:20:52 -05:00
Glenn Randers-Pehrson	29135161d7	[libpng16] Avoid filter-selection heuristic sum calculations in cases where only one filter is a candidate for selection. This trades off code size (added png_setup_*_row_only() functions) for speed.	2016-06-19 18:43:35 -05:00
John Bowler	9c04f57cab	[libpng15] Corrected filter heuristic overflow handling.	2016-06-19 18:01:33 -05:00
John Bowler	e1123aa80c	Merge branch 'libpng16' of ../../libpng into libpng16	2016-06-12 06:51:09 -07:00
Glenn Randers-Pehrson	4a8105e925	[libpng16] Bump version to 1.6.24beta02	2016-06-11 18:07:44 -05:00
Glenn Randers-Pehrson	51df269afe	[libpng16] Imported from libpng-1.6.24beta01.tar	2016-06-11 18:07:22 -05:00
John Bowler	bf2613b975	Merge branch 'libpng16' of ../../libpng into libpng16	2016-06-11 14:18:35 -07:00
John Bowler	5c6b7e177c	[libpng16] Avoid potential overflow of the PNG_IMAGE_SIZE macro. This macro is not used within libpng, but is used in some of the examples.	2016-06-11 14:11:09 -05:00
Glenn Randers-Pehrson	428f5ddabd	[libpng16] Bump version to 1.6.24beta01	2016-06-11 14:10:03 -05:00
John Bowler	a4b26efa1f	Change image size checks This covers the case where PNG_IMAGE_BUFFER_SIZE can overflow in the application as a result of the application using an increased 'row_stride'; previously png_image_finish_read only checked for overflow on the base calculation of components. (I.e. it checked for overflow of a 32-bit number on the total number of pixel components in the output format, not the possibly padded row length and not the number of bytes, which for linear formats is twice the number of components.) Signed-off-by: John Bowler <jbowler@acm.org>	2016-06-11 10:04:28 -07:00
Glenn Randers-Pehrson	ed6db9d86b	[libpng16] Imported from libpng-1.6.23.tar	2016-06-09 06:49:42 -05:00
Glenn Randers-Pehrson	ee3c4e43ae	[libpng16] Fixed bad link to RFC2083 in png.5 (Nikola Forro).	2016-06-07 08:22:18 -05:00
Glenn Randers-Pehrson	6d4e4d0cce	[libpng16] Imported from libpng-1.6.23rc02.tar	2016-06-03 21:28:20 -05:00
Glenn Randers-Pehrson	89158b9ad1	[libpng16] Fixed undefined behavior in png_push_save_buffer(). Do not call memcpy() with a null source, even if count is zero (Leon Scroggins III).	2016-06-03 18:40:42 -05:00
Glenn Randers-Pehrson	1fdac25f66	[libpng16] Imported from libpng-1.6.23rc01.tar	2016-06-01 19:17:57 -05:00
Glenn Randers-Pehrson	1017744c94	[libpng16] Added missing ")" in pngerror.c (Matt Sarrett).	2016-06-01 08:59:48 -05:00
Glenn Randers-Pehrson	f757d74898	[libpng16] Moved sse2 prototype from pngpriv.h to contrib/intel/intel_sse.patch.	2016-05-31 09:45:17 -05:00
John Bowler	bd2370c054	pngvalid.c: don't use size_t count arguments Coverity rejects code where an array element count has type size_t, this elminates the code in question from contrib/libtests/pngvalid.c Signed-off-by: John Bowler <jbowler@acm.org>	2016-05-30 08:12:51 -07:00
Glenn Randers-Pehrson	dbfd68ae3a	[libpng16] Update CHANGES, ANNOUNCE, and change date in pngvalid.c	2016-05-29 15:47:57 -05:00
John Bowler	801b925edf	pngvalid.c: correct progressive read input buffer The previous version of the code invariably passed just one byte at a time to libpng. The intention was to pass a random number of bytes in the range 0..511 (and this is what happens now). Signed-off-by: John Bowler <jbowler@acm.org>	2016-05-29 09:30:00 -07:00
Glenn Randers-Pehrson	a201f859cd	[libpng16] Bump version to 1.6.23beta02	2016-05-29 09:52:31 -05:00
Glenn Randers-Pehrson	84cc738166	[libpng16] Imported from libpng-1.6.23beta01.tar	2016-05-29 09:47:30 -05:00
John Bowler	81f0273d54	[libpng16] Added tests in pngvalid.c to check zero-length IDAT chunks in various positions. Fixed the sequential reader to handle these more robustly (John Bowler).	2016-05-29 09:45:33 -05:00
Timothy Nikkel	3f46c67c69	[libpng16] Fixed the progressive reader to handle empty first IDAT chunk properly (patch by Timothy Nikkel).	2016-05-29 09:44:04 -05:00
Glenn Randers-Pehrson	6c7459e455	[libpng16] Ensure png_ptr->trans_values is set in png_set_tRNS().	2016-05-27 20:09:23 -05:00
Glenn Randers-Pehrson	8d16725373	[libpng16] Stop a potential memleak in png_set_tRNS() (Bug report by Ted Ying).	2016-05-27 19:55:44 -05:00
Glenn Randers-Pehrson	4e34fd3b8a	[libpng16] Bump version to 1.6.23beta01	2016-05-27 19:48:24 -05:00