ANNOUNCE - third_party/libpng - Git at Google


 Libpng 1.5.7beta05 - November 23, 2011

 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

    1.5.7beta05.tar.xz (LZMA-compressed, recommended)
    1.5.7beta05.tar.gz
    1.5.7beta05.tar.bz2

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

    lp157b05.7z  (LZMA-compressed, recommended)
    lp157b05.zip

 Other information:

    1.5.7beta05-README.txt
    1.5.7beta05-LICENSE.txt

 Changes since the last public release (1.5.6):

 Version 1.5.7beta01 [November 4, 2011]
   Added support for ARM processor (Mans Rullgard)
   Fixed bug in pngvalid on early allocation failure; fixed type cast in
     pngmem.c; pngvalid would attempt to call png_error() if the allocation
     of a png_struct or png_info failed. This would probably have led to a
     crash.  The pngmem.c implementation of png_malloc() included a cast
     to png_size_t which would fail on large allocations on 16-bit systems.
   Fix for the preprocessor of the Intel C compiler. The preprocessor
     splits adjacent @ signs with a space; this changes the concatentation
     token from @-@-@ to PNG_JOIN; that should work with all compiler
     preprocessors.
   Paeth filter speed improvements from work by Siarhei Siamashka. This
     changes the 'Paeth' reconstruction function to improve the GCC code
     generation on x86. The changes are only part of the suggested ones;
     just the changes that definitely improve speed and remain simple.
     The changes also slightly increase the clarity of the code.

 Version 1.5.7beta02 [November 11, 2011]
   Check compression_type parameter in png_get_iCCP and remove spurious
     casts. The compression_type parameter is always assigned to, so must
     be non-NULL. The cast of the profile length potentially truncated the
     value unnecessarily on a 16-bit int system, so the cast of the (byte)
     compression type to (int) is specified by ANSI-C anyway.
   Fixed FP division by zero in pngvalid.c; the 'test_pixel' code left
     the sBIT fields in the test pixel as 0, which resulted in a floating
     point division by zero which was irrelevant but causes systems where
     FP exceptions cause a crash. Added code to pngvalid to turn on FP
     exceptions if the appropriate glibc support is there to ensure this is
     tested in the future.
   Updated scripts/pnglibconf.mak and scripts/makefile.std to handle the
     new PNG_JOIN macro.
   Added versioning to pnglibconf.h comments.
   Simplified read/write API initial version; basic read/write tested on
     a variety of images, limited documentation (in the header file.)
   Installed more accurate linear to sRGB conversion tables. The slightly
     modified tables reduce the number of 16-bit values that
     convert to an off-by-one 8-bit value.  The "makesRGB.c" code that was used
     to generate the tables is now in a contrib/sRGBtables sub-directory.

 Version 1.5.7beta03 [November 17, 2011]
   Removed PNG_CONST from the sRGB table declarations in pngpriv.h and png.c
   Added run-time detection of NEON support.
   Added contrib/libtests; includes simplified API test and timing test and
     a color conversion utility for rapid checking of failed 'pngstest' results.
   Multiple transform bug fixes plus a work-round for double gamma correction.
     libpng does not support more than one transform that requires linear data
     at once - if this is tried typically the results is double gamma
     correction. Since the simplified APIs can need rgb to gray combined with
     a compose operation it is necessary to do one of these outside the main
     libpng transform code. This check-in also contains fixes to various bugs
     in the simplified APIs themselves and to some bugs in compose and rgb to
     gray (on palette) itself.
   Fixes for C++ compilation using g++ When libpng source is compiled
     using g++. The compiler imposes C++ rules on the C source; thus it
     is desireable to make the source work with either C or C++ rules
     without throwing away useful error information.  This change adds
     png_voidcast to allow C semantic (void*) cases or the corresponding
     C++ static_cast operation, as appropriate.
   Added --noexecstack to assembler file compilation. GCC does not set
     this on assembler compilation, even though it does on C compilation.
     This creates security issues if assembler code is enabled; the
     work-around is to set it by default in the flags for $(CCAS)
   Work around compilers that don't support declaration of const data. Some
     compilers fault 'extern const' data declarations (because the data is
     not initialized); this turns on const-ness only for compilers where
     this is known to work.

 Version 1.5.7beta04 [November 17, 2011]
   Since the gcc driver does not recognize the --noexecstack flag, we must
     use the -Wa prefix to have it passed through to the assembler.
     Also removed a duplicate setting of this flag.
   Added files that were omitted from the libpng-1.5.7beta03 zip distribution.

 Version 1.5.7beta05 [November 23, 2011]
   Removed "zTXt" from warning in generic chunk decompression function.
   Validate time settings passed to pngset() and png_convert_to_rfc1123()
     (Frank Busse).
   Added MINGW support to CMakeLists.txt
   Reject invalid compression flag or method when reading the iTXt chunk.
   Backed out 'simplified' API changes. The API seems too complex and there
     is a lack of consensus or enthusiasm for the proposals.  The API also
     reveals significant bugs inside libpng (double gamma correction and the
     known bug of being unable to retrieve a corrected palette.) It seems
     better to wait until the bugs, at least, are corrected.

 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) or to glennrp at users.sourceforge.net

 Glenn R-P

	Libpng 1.5.7beta05 - November 23, 2011

	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

	1.5.7beta05.tar.xz (LZMA-compressed, recommended)
	1.5.7beta05.tar.gz
	1.5.7beta05.tar.bz2

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

	lp157b05.7z (LZMA-compressed, recommended)
	lp157b05.zip

	Other information:

	1.5.7beta05-README.txt
	1.5.7beta05-LICENSE.txt

	Changes since the last public release (1.5.6):

	Version 1.5.7beta01 [November 4, 2011]
	Added support for ARM processor (Mans Rullgard)
	Fixed bug in pngvalid on early allocation failure; fixed type cast in
	pngmem.c; pngvalid would attempt to call png_error() if the allocation
	of a png_struct or png_info failed. This would probably have led to a
	crash. The pngmem.c implementation of png_malloc() included a cast
	to png_size_t which would fail on large allocations on 16-bit systems.
	Fix for the preprocessor of the Intel C compiler. The preprocessor
	splits adjacent @ signs with a space; this changes the concatentation
	token from @-@-@ to PNG_JOIN; that should work with all compiler
	preprocessors.
	Paeth filter speed improvements from work by Siarhei Siamashka. This
	changes the 'Paeth' reconstruction function to improve the GCC code
	generation on x86. The changes are only part of the suggested ones;
	just the changes that definitely improve speed and remain simple.
	The changes also slightly increase the clarity of the code.

	Version 1.5.7beta02 [November 11, 2011]
	Check compression_type parameter in png_get_iCCP and remove spurious
	casts. The compression_type parameter is always assigned to, so must
	be non-NULL. The cast of the profile length potentially truncated the
	value unnecessarily on a 16-bit int system, so the cast of the (byte)
	compression type to (int) is specified by ANSI-C anyway.
	Fixed FP division by zero in pngvalid.c; the 'test_pixel' code left
	the sBIT fields in the test pixel as 0, which resulted in a floating
	point division by zero which was irrelevant but causes systems where
	FP exceptions cause a crash. Added code to pngvalid to turn on FP
	exceptions if the appropriate glibc support is there to ensure this is
	tested in the future.
	Updated scripts/pnglibconf.mak and scripts/makefile.std to handle the
	new PNG_JOIN macro.
	Added versioning to pnglibconf.h comments.
	Simplified read/write API initial version; basic read/write tested on
	a variety of images, limited documentation (in the header file.)
	Installed more accurate linear to sRGB conversion tables. The slightly
	modified tables reduce the number of 16-bit values that
	convert to an off-by-one 8-bit value. The "makesRGB.c" code that was used
	to generate the tables is now in a contrib/sRGBtables sub-directory.

	Version 1.5.7beta03 [November 17, 2011]
	Removed PNG_CONST from the sRGB table declarations in pngpriv.h and png.c
	Added run-time detection of NEON support.
	Added contrib/libtests; includes simplified API test and timing test and
	a color conversion utility for rapid checking of failed 'pngstest' results.
	Multiple transform bug fixes plus a work-round for double gamma correction.
	libpng does not support more than one transform that requires linear data
	at once - if this is tried typically the results is double gamma
	correction. Since the simplified APIs can need rgb to gray combined with
	a compose operation it is necessary to do one of these outside the main
	libpng transform code. This check-in also contains fixes to various bugs
	in the simplified APIs themselves and to some bugs in compose and rgb to
	gray (on palette) itself.
	Fixes for C++ compilation using g++ When libpng source is compiled
	using g++. The compiler imposes C++ rules on the C source; thus it
	is desireable to make the source work with either C or C++ rules
	without throwing away useful error information. This change adds
	png_voidcast to allow C semantic (void*) cases or the corresponding
	C++ static_cast operation, as appropriate.
	Added --noexecstack to assembler file compilation. GCC does not set
	this on assembler compilation, even though it does on C compilation.
	This creates security issues if assembler code is enabled; the
	work-around is to set it by default in the flags for $(CCAS)
	Work around compilers that don't support declaration of const data. Some
	compilers fault 'extern const' data declarations (because the data is
	not initialized); this turns on const-ness only for compilers where
	this is known to work.

	Version 1.5.7beta04 [November 17, 2011]
	Since the gcc driver does not recognize the --noexecstack flag, we must
	use the -Wa prefix to have it passed through to the assembler.
	Also removed a duplicate setting of this flag.
	Added files that were omitted from the libpng-1.5.7beta03 zip distribution.

	Version 1.5.7beta05 [November 23, 2011]
	Removed "zTXt" from warning in generic chunk decompression function.
	Validate time settings passed to pngset() and png_convert_to_rfc1123()
	(Frank Busse).
	Added MINGW support to CMakeLists.txt
	Reject invalid compression flag or method when reading the iTXt chunk.
	Backed out 'simplified' API changes. The API seems too complex and there
	is a lack of consensus or enthusiasm for the proposals. The API also
	reveals significant bugs inside libpng (double gamma correction and the
	known bug of being unable to retrieve a corrected palette.) It seems
	better to wait until the bugs, at least, are corrected.

	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) or to glennrp at users.sourceforge.net

	Glenn R-P