Home | History | Annotate | Download | only in libpng
      1 /*
      2 CHANGES - changes for libpng
      3 
      4 version 0.2
      5   added reader into png.h
      6   fixed small problems in stub file
      7 
      8 version 0.3
      9   added pull reader
     10   split up pngwrite.c to several files
     11   added pnglib.txt
     12   added example.c
     13   cleaned up writer, adding a few new transformations
     14   fixed some bugs in writer
     15   interfaced with zlib 0.5
     16   added K&R support
     17   added check for 64 KB blocks for 16 bit machines
     18 
     19 version 0.4
     20   cleaned up code and commented code
     21   simplified time handling into png_time
     22   created png_color_16 and png_color_8 to handle color needs
     23   cleaned up color type defines
     24   fixed various bugs
     25   made various names more consistent
     26   interfaced with zlib 0.71
     27   cleaned up zTXt reader and writer (using zlib's Reset functions)
     28   split transformations into pngrtran.c and pngwtran.c
     29 
     30 version 0.5
     31   interfaced with zlib 0.8
     32   fixed many reading and writing bugs
     33   saved using 3 spaces instead of tabs
     34 
     35 version 0.6
     36   added png_large_malloc() and png_large_free()
     37   added png_size_t
     38   cleaned up some compiler warnings
     39   added png_start_read_image()
     40 
     41 version 0.7
     42   cleaned up lots of bugs
     43   finished dithering and other stuff
     44   added test program
     45   changed name from pnglib to libpng
     46 
     47 version 0.71 [June, 1995]
     48   changed pngtest.png for zlib 0.93
     49   fixed error in libpng.txt and example.c
     50 
     51 version 0.8
     52   cleaned up some bugs
     53   added png_set_filler()
     54   split up pngstub.c into pngmem.c, pngio.c, and pngerror.c
     55   added #define's to remove unwanted code
     56   moved png_info_init() to png.c
     57   added old_size into png_realloc()
     58   added functions to manually set filtering and compression info
     59   changed compression parameters based on image type
     60   optimized filter selection code
     61   added version info
     62   changed external functions passing floats to doubles (k&r problems?)
     63   put all the configurable stuff in pngconf.h
     64   enabled png_set_shift to work with paletted images on read
     65   added png_read_update_info() - updates info structure with
     66      transformations
     67 
     68 version 0.81 [August, 1995]
     69   incorporated Tim Wegner's medium model code (thanks, Tim)
     70 
     71 version 0.82 [September, 1995]
     72   [unspecified changes]
     73 
     74 version 0.85 [December, 1995]
     75   added more medium model code (almost everything's a far)
     76   added i/o, error, and memory callback functions
     77   fixed some bugs (16 bit, 4 bit interlaced, etc.)
     78   added first run progressive reader (barely tested)
     79 
     80 version 0.86 [January, 1996]
     81   fixed bugs
     82   improved documentation
     83 
     84 version 0.87 [January, 1996]
     85   fixed medium model bugs
     86   fixed other bugs introduced in 0.85 and 0.86
     87   added some minor documentation
     88 
     89 version 0.88 [January, 1996]
     90   fixed progressive bugs
     91   replaced tabs with spaces
     92   cleaned up documentation
     93   added callbacks for read/write and warning/error functions
     94 
     95 version 0.89 [July, 1996]
     96   added new initialization API to make libpng work better with shared libs
     97      we now have png_create_read_struct(), png_create_write_struct(),
     98      png_create_info_struct(), png_destroy_read_struct(), and
     99      png_destroy_write_struct() instead of the separate calls to
    100      malloc and png_read_init(), png_info_init(), and png_write_init()
    101   changed warning/error callback functions to fix bug - this means you
    102      should use the new initialization API if you were using the old
    103      png_set_message_fn() calls, and that the old API no longer exists
    104      so that people are aware that they need to change their code
    105   changed filter selection API to allow selection of multiple filters
    106      since it didn't work in previous versions of libpng anyways
    107   optimized filter selection code
    108   fixed png_set_background() to allow using an arbitrary RGB color for
    109      paletted images
    110   fixed gamma and background correction for paletted images, so
    111      png_correct_palette is not needed unless you are correcting an
    112      external palette (you will need to #define PNG_CORRECT_PALETTE_SUPPORTED
    113      in pngconf.h) - if nobody uses this, it may disappear in the future.
    114   fixed bug with Borland 64K memory allocation (Alexander Lehmann)
    115   fixed bug in interlace handling (Smarasderagd, I think)
    116   added more error checking for writing and image to reduce invalid files
    117   separated read and write functions so that they won't both be linked
    118      into a binary when only reading or writing functionality is used
    119   new pngtest image also has interlacing and zTXt
    120   updated documentation to reflect new API
    121 
    122 version 0.90 [January, 1997]
    123   made CRC errors/warnings on critical and ancillary chunks configurable
    124   libpng will use the zlib CRC routines by (compile-time) default
    125   changed DOS small/medium model memory support - needs zlib 1.04 (Tim Wegner)
    126   added external C++ wrapper statements to png.h (Gilles Dauphin)
    127   allow PNG file to be read when some or all of file signature has already
    128      been read from the beginning of the stream.  ****This affects the size
    129      of info_struct and invalidates all programs that use a shared libpng****
    130   fixed png_filler() declarations
    131   fixed? background color conversions
    132   fixed order of error function pointers to match documentation
    133   current chunk name is now available in png_struct to reduce the number
    134      of nearly identical error messages (will simplify multi-lingual
    135      support when available)
    136   try to get ready for unknown-chunk callback functions:
    137      - previously read critical chunks are flagged, so the chunk handling
    138        routines can determine if the chunk is in the right place
    139      - all chunk handling routines have the same prototypes, so we will
    140        be able to handle all chunks via a callback mechanism
    141   try to fix Linux "setjmp" buffer size problems
    142   removed png_large_malloc, png_large_free, and png_realloc functions.
    143 
    144 version 0.95 [March, 1997]
    145   fixed bug in pngwutil.c allocating "up_row" twice and "avg_row" never
    146   fixed bug in PNG file signature compares when start != 0
    147   changed parameter type of png_set_filler(...filler...) from png_byte
    148      to png_uint_32
    149   added test for MACOS to ensure that both math.h and fp.h are not #included
    150   added macros for libpng to be compiled as a Windows DLL (Andreas Kupries)
    151   added "packswap" transformation, which changes the endianness of
    152      packed-pixel bytes (Kevin Bracey)
    153   added "strip_alpha" transformation, which removes the alpha channel of
    154      input images without using it (not necessarily a good idea)
    155   added "swap_alpha" transformation, which puts the alpha channel in front
    156      of the color bytes instead of after
    157   removed all implicit variable tests which assume NULL == 0 (I think)
    158   changed several variables to "png_size_t" to show 16/32-bit limitations
    159   added new pCAL chunk read/write support
    160   added experimental filter selection weighting (Greg Roelofs)
    161   removed old png_set_rgbx() and png_set_xrgb() functions that have been
    162      obsolete for about 2 years now (use png_set_filler() instead)
    163   added macros to read 16- and 32-bit ints directly from buffer, to be
    164      used only on those systems that support it (namely PowerPC and 680x0)
    165      With some testing, this may become the default for MACOS/PPC systems.
    166   only calculate CRC on data if we are going to use it
    167   added macros for zTXt compression type PNG_zTXt_COMPRESSION_???
    168   added macros for simple libpng debugging output selectable at compile time
    169   removed PNG_READ_END_MODE in progressive reader (Smarasderagd)
    170   more description of info_struct in libpng.txt and png.h
    171   more instructions in example.c
    172   more chunk types tested in pngtest.c
    173   renamed pngrcb.c to pngset.c, and all png_read_<chunk> functions to be
    174      png_set_<chunk>.  We now have corresponding png_get_<chunk>
    175      functions in pngget.c to get information in info_ptr.  This isolates
    176      the application from the internal organization of png_info_struct
    177      (good for shared library implementations).
    178 
    179 version 0.96 [May, 1997]
    180   fixed serious bug with < 8bpp images introduced in 0.95
    181   fixed 256-color transparency bug (Greg Roelofs)
    182   fixed up documentation (Greg Roelofs, Laszlo Nyul)
    183   fixed "error" in pngconf.h for Linux setjmp() behaviour
    184   fixed DOS medium model support (Tim Wegner)
    185   fixed png_check_keyword() for case with error in static string text
    186   added read of CRC after IEND chunk for embedded PNGs (Laszlo Nyul)
    187   added typecasts to quiet compiler errors
    188   added more debugging info
    189 
    190 version 0.97 [January, 1998]
    191   removed PNG_USE_OWN_CRC capability
    192   relocated png_set_crc_action from pngrutil.c to pngrtran.c
    193   fixed typecasts of "new_key", etc. (Andreas Dilger)
    194   added RFC 1152 [sic] date support
    195   fixed bug in gamma handling of 4-bit grayscale
    196   added 2-bit grayscale gamma handling (Glenn R-P)
    197   added more typecasts. 65536L becomes (png_uint_32)65536L, etc. (Glenn R-P)
    198   minor corrections in libpng.txt
    199   added simple sRGB support (Glenn R-P)
    200   easier conditional compiling, e.g. define PNG_READ/WRITE_NOT_FULLY_SUPPORTED;
    201      all configurable options can be selected from command-line instead
    202      of having to edit pngconf.h (Glenn R-P)
    203   fixed memory leak in pngwrite.c (free info_ptr->text) (Glenn R-P)
    204   added more conditions for png_do_background, to avoid changing
    205      black pixels to background when a background is supplied and
    206      no pixels are transparent
    207   repaired PNG_NO_STDIO behaviour
    208   tested NODIV support and made it default behaviour (Greg Roelofs)
    209   added "-m" option and PNGTEST_DEBUG_MEMORY to pngtest (John Bowler)
    210   regularized version numbering scheme and bumped shared-library major
    211      version number to 2 to avoid problems with libpng 0.89 apps (Greg Roelofs)
    212 
    213 version 0.98 [January, 1998]
    214   cleaned up some typos in libpng.txt and in code documentation
    215   fixed memory leaks in pCAL chunk processing (Glenn R-P and John Bowler)
    216   cosmetic change "display_gamma" to "screen_gamma" in pngrtran.c
    217   changed recommendation about file_gamma for PC images to .51 from .45,
    218      in example.c and libpng.txt, added comments to distinguish between
    219      screen_gamma, viewing_gamma, and display_gamma.
    220   changed all references to RFC1152 to read RFC1123 and changed the
    221      PNG_TIME_RFC1152_SUPPORTED macro to PNG_TIME_RFC1123_SUPPORTED
    222   added png_invert_alpha capability (Glenn R-P -- suggestion by Jon Vincent)
    223   changed srgb_intent from png_byte to int to avoid compiler bugs
    224 
    225 version 0.99 [January 30, 1998]
    226   free info_ptr->text instead of end_info_ptr->text in pngread.c (John Bowler)
    227   fixed a longstanding "packswap" bug in pngtrans.c
    228   fixed some inconsistencies in pngconf.h that prevented compiling with
    229      PNG_READ_GAMMA_SUPPORTED and PNG_READ_hIST_SUPPORTED undefined
    230   fixed some typos and made other minor rearrangement of libpng.txt (Andreas)
    231   changed recommendation about file_gamma for PC images to .50 from .51 in
    232      example.c and libpng.txt, and changed file_gamma for sRGB images to .45
    233   added a number of functions to access information from the png structure
    234      png_get_image_height(), etc. (Glenn R-P, suggestion by Brad Pettit)
    235   added TARGET_MACOS similar to zlib-1.0.8
    236   define PNG_ALWAYS_EXTERN when __MWERKS__ && WIN32 are defined
    237   added type casting to all png_malloc() function calls
    238 version 0.99a [January 31, 1998]
    239   Added type casts and parentheses to all returns that return a value.(Tim W.)
    240 version 0.99b [February 4, 1998]
    241   Added type cast png_uint_32 on malloc function calls where needed.
    242   Changed type of num_hist from png_uint_32 to int (same as num_palette).
    243   Added checks for rowbytes overflow, in case png_size_t is less than 32 bits.
    244   Renamed makefile.elf to makefile.lnx.
    245 version 0.99c [February 7, 1998]
    246   More type casting.  Removed erroneous overflow test in pngmem.c.
    247   Added png_buffered_memcpy() and png_buffered_memset(), apply them to rowbytes.
    248   Added UNIX manual pages libpng.3 (incorporating libpng.txt) and  png.5.
    249 version 0.99d [February 11, 1998]
    250   Renamed "far_to_near()" "png_far_to_near()"
    251   Revised libpng.3
    252   Version 99c "buffered" operations didn't work as intended.  Replaced them
    253     with png_memcpy_check() and png_memset_check().
    254   Added many "if (png_ptr == NULL) return" to quell compiler warnings about
    255     unused png_ptr, mostly in pngget.c and pngset.c.
    256   Check for overlength tRNS chunk present when indexed-color PLTE is read.
    257   Cleaned up spelling errors in libpng.3/libpng.txt
    258   Corrected a problem with png_get_tRNS() which returned undefined trans array
    259 version 0.99e [February 28, 1998]
    260   Corrected png_get_tRNS() again.
    261   Add parentheses for easier reading of pngget.c, fixed "||" should be "&&".
    262   Touched up example.c to make more of it compileable, although the entire
    263     file still can't be compiled (Willem van Schaik)
    264   Fixed a bug in png_do_shift() (Bryan Tsai)
    265   Added a space in png.h prototype for png_write_chunk_start()
    266   Replaced pngtest.png with one created with zlib 1.1.1
    267   Changed pngtest to report PASS even when file size is different (Jean-loup G.)
    268   Corrected some logic errors in png_do_invert_alpha() (Chris Patterson)
    269 version 0.99f [March 5, 1998]
    270   Corrected a bug in pngpread() introduced in version 99c (Kevin Bracey)
    271   Moved makefiles into a "scripts" directory, and added INSTALL instruction file
    272   Added makefile.os2 and pngos2.def (A. Zabolotny) and makefile.s2x (W. Sebok)
    273   Added pointers to "note on libpng versions" in makefile.lnx and README
    274   Added row callback feature when reading and writing nonprogressive rows
    275      and added a test of this feature in pngtest.c
    276   Added user transform callbacks, with test of the feature in pngtest.c
    277 version 0.99g [March 6, 1998, morning]
    278   Minor changes to pngtest.c to suppress compiler warnings.
    279   Removed "beta" language from documentation.
    280 version 0.99h [March 6, 1998, evening]
    281   Minor changes to previous minor changes to pngtest.c
    282   Changed PNG_READ_NOT_FULLY_SUPPORTED to PNG_READ_TRANSFORMS_NOT_SUPPORTED
    283   and added PNG_PROGRESSIVE_READ_NOT_SUPPORTED macro
    284   Added user transform capability
    285 
    286 version 1.00 [March 7, 1998]
    287   Changed several typedefs in pngrutil.c
    288   Added makefile.wat (Pawel Mrochen), updated makefile.tc3 (Willem van Schaik)
    289   replaced "while(1)" with "for(;;)"
    290   added PNGARG() to prototypes in pngtest.c and removed some prototypes
    291   updated some of the makefiles (Tom Lane)
    292   changed some typedefs (s_start, etc.) in pngrutil.c
    293   fixed dimensions of "short_months" array in pngwrite.c
    294   Replaced ansi2knr.c with the one from jpeg-v6
    295 
    296 version 1.0.0 [March 8, 1998]
    297   Changed name from 1.00 to 1.0.0 (Adam Costello)
    298   Added smakefile.ppc (with SCOPTIONS.ppc) for Amiga PPC (Andreas Kleinert)
    299 version 1.0.0a [March 9, 1998]
    300   Fixed three bugs in pngrtran.c to make gamma+background handling consistent
    301   (Greg Roelofs)
    302   Changed format of the PNG_LIBPNG_VER integer to xyyzz instead of xyz
    303   for major, minor, and bugfix releases.  This is 10001. (Adam Costello,
    304   Tom Lane)
    305   Make months range from 1-12 in png_convert_to_rfc1123
    306 version 1.0.0b [March 13, 1998]
    307   Quieted compiler complaints about two empty "for" loops in pngrutil.c
    308   Minor changes to makefile.s2x
    309   Removed #ifdef/#endif around a png_free() in pngread.c
    310 
    311 version 1.0.1 [March 14, 1998]
    312   Changed makefile.s2x to reduce security risk of using a relative pathname
    313   Fixed some typos in the documentation (Greg).
    314   Fixed a problem with value of "channels" returned by png_read_update_info()
    315 version 1.0.1a [April 21, 1998]
    316   Optimized Paeth calculations by replacing abs() function calls with intrinsics
    317   plus other loop optimizations. Improves avg decoding speed by about 20%.
    318   Commented out i386istic "align" compiler flags in makefile.lnx.
    319   Reduced the default warning level in some makefiles, to make them consistent.
    320   Removed references to IJG and JPEG in the ansi2knr.c copyright statement.
    321   Fixed a bug in png_do_strip_filler with XXRRGGBB => RRGGBB transformation.
    322   Added grayscale and 16-bit capability to png_do_read_filler().
    323   Fixed a bug in pngset.c, introduced in version 0.99c, that sets rowbytes
    324     too large when writing an image with bit_depth < 8 (Bob Dellaca).
    325   Corrected some bugs in the experimental weighted filtering heuristics.
    326   Moved a misplaced pngrutil code block that truncates tRNS if it has more
    327     than num_palette entries -- test was done before num_palette was defined.
    328   Fixed a png_convert_to_rfc1123() bug that converts day 31 to 0 (Steve Eddins).
    329   Changed compiler flags in makefile.wat for better optimization (Pawel Mrochen).
    330 version 1.0.1b [May 2, 1998]
    331   Relocated png_do_gray_to_rgb() within png_do_read_transformations() (Greg).
    332   Relocated the png_composite macros from pngrtran.c to png.h (Greg).
    333   Added makefile.sco (contributed by Mike Hopkirk).
    334   Fixed two bugs (missing definitions of "istop") introduced in libpng-1.0.1a.
    335   Fixed a bug in pngrtran.c that would set channels=5 under some circumstances.
    336   More work on the Paeth-filtering, achieving imperceptible speedup (A Kleinert).
    337   More work on loop optimization which may help when compiled with C++ compilers.
    338   Added warnings when people try to use transforms they've defined out.
    339   Collapsed 4 "i" and "c" loops into single "i" loops in pngrtran and pngwtran.
    340   Revised paragraph about png_set_expand() in libpng.txt and libpng.3 (Greg)
    341 version 1.0.1c [May 11, 1998]
    342   Fixed a bug in pngrtran.c (introduced in libpng-1.0.1a) where the masks for
    343     filler bytes should have been 0xff instead of 0xf.
    344   Added max_pixel_depth=32 in pngrutil.c when using FILLER with palette images.
    345   Moved PNG_WRITE_WEIGHTED_FILTER_SUPPORTED and PNG_WRITE_FLUSH_SUPPORTED
    346     out of the PNG_WRITE_TRANSFORMS_NOT_SUPPORTED block of pngconf.h
    347   Added "PNG_NO_WRITE_TRANSFORMS" etc., as alternatives for *_NOT_SUPPORTED,
    348     for consistency, in pngconf.h
    349   Added individual "ifndef PNG_NO_[CAPABILITY]" in pngconf.h to make it easier
    350     to remove unwanted capabilities via the compile line
    351   Made some corrections to grammar (which, it's) in documentation (Greg).
    352   Corrected example.c, use of row_pointers in png_write_image().
    353 version 1.0.1d [May 24, 1998]
    354   Corrected several statements that used side effects illegally in pngrutil.c
    355     and pngtrans.c, that were introduced in version 1.0.1b
    356   Revised png_read_rows() to avoid repeated if-testing for NULL (A Kleinert)
    357   More corrections to example.c, use of row_pointers in png_write_image()
    358     and png_read_rows().
    359   Added pngdll.mak and pngdef.pas to scripts directory, contributed by
    360     Bob Dellaca, to make a png32bd.dll with Borland C++ 4.5
    361   Fixed error in example.c with png_set_text: num_text is 3, not 2 (Guido V.)
    362   Changed several loops from count-down to count-up, for consistency.
    363 version 1.0.1e [June 6, 1998]
    364   Revised libpng.txt and libpng.3 description of png_set_read|write_fn(), and
    365     added warnings when people try to set png_read_fn and png_write_fn in
    366     the same structure.
    367   Added a test such that png_do_gamma will be done when num_trans==0
    368     for truecolor images that have defined a background.  This corrects an
    369     error that was introduced in libpng-0.90 that can cause gamma processing
    370     to be skipped.
    371   Added tests in png.h to include "trans" and "trans_values" in structures
    372     when PNG_READ_BACKGROUND_SUPPORTED or PNG_READ_EXPAND_SUPPORTED is defined.
    373   Add png_free(png_ptr->time_buffer) in png_destroy_read_struct()
    374   Moved png_convert_to_rfc_1123() from pngwrite.c to png.c
    375   Added capability for user-provided malloc_fn() and free_fn() functions,
    376     and revised pngtest.c to demonstrate their use, replacing the
    377     PNGTEST_DEBUG_MEM feature.
    378   Added makefile.w32, for Microsoft C++ 4.0 and later (Tim Wegner).
    379 
    380 version 1.0.2 [June 14, 1998]
    381   Fixed two bugs in makefile.bor .
    382 version 1.0.2a [December 30, 1998]
    383   Replaced and extended code that was removed from png_set_filler() in 1.0.1a.
    384   Fixed a bug in png_do_filler() that made it fail to write filler bytes in
    385     the left-most pixel of each row (Kevin Bracey).
    386   Changed "static pngcharp tIME_string" to "static char tIME_string[30]"
    387     in pngtest.c (Duncan Simpson).
    388   Fixed a bug in pngtest.c that caused pngtest to try to write a tIME chunk
    389     even when no tIME chunk was present in the source file.
    390   Fixed a problem in pngrutil.c: gray_to_rgb didn't always work with 16-bit.
    391   Fixed a problem in png_read_push_finish_row(), which would not skip some
    392     passes that it should skip, for images that are less than 3 pixels high.
    393   Interchanged the order of calls to png_do_swap() and png_do_shift()
    394     in pngwtran.c (John Cromer).
    395   Added #ifdef PNG_DEBUG/#endif surrounding use of PNG_DEBUG in png.h .
    396   Changed "bad adaptive filter type" from error to warning in pngrutil.c .
    397   Fixed a documentation error about default filtering with 8-bit indexed-color.
    398   Separated the PNG_NO_STDIO macro into PNG_NO_STDIO and PNG_NO_CONSOLE_IO
    399     (L. Peter Deutsch).
    400   Added png_set_rgb_to_gray() and png_get_rgb_to_gray_status() functions.
    401   Added png_get_copyright() and png_get_header_version() functions.
    402   Revised comments on png_set_progressive_read_fn() in libpng.txt and example.c
    403   Added information about debugging in libpng.txt and libpng.3 .
    404   Changed "ln -sf" to "ln -s -f" in makefile.s2x, makefile.lnx, and makefile.sco.
    405   Removed lines after Dynamic Dependencies" in makefile.aco .
    406   Revised makefile.dec to make a shared library (Jeremie Petit).
    407   Removed trailing blanks from all files.
    408 version 1.0.2a [January 6, 1999]
    409   Removed misplaced #endif and #ifdef PNG_NO_EXTERN near the end of png.h
    410   Added "if" tests to silence complaints about unused png_ptr in png.h and png.c
    411   Changed "check_if_png" function in example.c to return true (nonzero) if PNG.
    412   Changed libpng.txt to demonstrate png_sig_cmp() instead of png_check_sig()
    413     which is obsolete.
    414 
    415 version 1.0.3 [January 14, 1999]
    416   Added makefile.hux, for Hewlett Packard HPUX 10.20 and 11.00 (Jim Rice)
    417   Added a statement of Y2K compliance in png.h, libpng.3, and Y2KINFO.
    418 version 1.0.3a [August 12, 1999]
    419   Added check for PNG_READ_INTERLACE_SUPPORTED in pngread.c; issue a warning
    420      if an attempt is made to read an interlaced image when it's not supported.
    421   Added check if png_ptr->trans is defined before freeing it in pngread.c
    422   Modified the Y2K statement to include versions back to version 0.71
    423   Fixed a bug in the check for valid IHDR bit_depth/color_types in pngrutil.c
    424   Modified makefile.wat (added -zp8 flag, ".symbolic", changed some comments)
    425   Replaced leading blanks with tab characters in makefile.hux
    426   Changed "dworkin.wustl.edu" to "ccrc.wustl.edu" in various documents.
    427   Changed (float)red and (float)green to (double)red, (double)green
    428      in png_set_rgb_to_gray() to avoid "promotion" problems in AIX.
    429   Fixed a bug in pngconf.h that omitted <stdio.h> when PNG_DEBUG==0 (K Bracey).
    430   Reformatted libpng.3 and libpngpf.3 with proper fonts (script by J. vanZandt).
    431   Updated documentation to refer to the PNG-1.2 specification.
    432   Removed ansi2knr.c and left pointers to the latest source for ansi2knr.c
    433     in makefile.knr, INSTALL, and README (L. Peter Deutsch)
    434   Fixed bugs in calculation of the length of rowbytes when adding alpha
    435     channels to 16-bit images, in pngrtran.c (Chris Nokleberg)
    436   Added function png_set_user_transform_info() to store user_transform_ptr,
    437     user_depth, and user_channels into the png_struct, and a function
    438     png_get_user_transform_ptr() to retrieve the pointer (Chris Nokleberg)
    439   Added function png_set_empty_plte_permitted() to make libpng useable
    440     in MNG applications.
    441   Corrected the typedef for png_free_ptr in png.h (Jesse Jones).
    442   Correct gamma with srgb is 45455 instead of 45000 in pngrutil.c, to be
    443     consistent with PNG-1.2, and allow variance of 500 before complaining.
    444   Added assembler code contributed by Intel in file pngvcrd.c and modified
    445     makefile.w32 to use it (Nirav Chhatrapati, INTEL Corporation, Gilles Vollant)
    446   Changed "ln -s -f" to "ln -f -s" in the makefiles to make Solaris happy.
    447   Added some aliases for png_set_expand() in pngrtran.c, namely
    448     png_set_expand_PLTE(), png_set_expand_depth(), and png_set_expand_tRNS()
    449     (Greg Roelofs, in "PNG: The Definitive Guide").
    450   Added makefile.beo for BEOS on X86, contributed by Sander Stok.
    451 version 1.0.3b [August 26, 1999]
    452   Replaced 2147483647L several places with PNG_MAX_UINT macro, defined in png.h
    453   Changed leading blanks to tabs in all makefiles.
    454   Define PNG_USE_PNGVCRD in makefile.w32, to get MMX assembler code.
    455   Made alternate versions of  png_set_expand() in pngrtran.c, namely
    456     png_set_gray_1_2_4_to_8, png_set_palette_to_rgb, and png_set_tRNS_to_alpha
    457     (Greg Roelofs, in "PNG: The Definitive Guide").  Deleted the 1.0.3a aliases.
    458   Relocated start of 'extern "C"' block in png.h so it doesn't include pngconf.h
    459   Revised calculation of num_blocks in pngmem.c to avoid a potentially
    460     negative shift distance, whose results are undefined in the C language.
    461   Added a check in pngset.c to prevent writing multiple tIME chunks.
    462   Added a check in pngwrite.c to detect invalid small window_bits sizes.
    463 version 1.0.3d [September 4, 1999]
    464   Fixed type casting of igamma in pngrutil.c
    465   Added new png_expand functions to scripts/pngdef.pas and pngos2.def
    466   Added a demo read_user_transform_fn that examines the row filters in pngtest.c
    467 
    468 version 1.0.4 [September 24, 1999]
    469   Define PNG_ALWAYS_EXTERN in pngconf.h if __STDC__ is defined
    470   Delete #define PNG_INTERNAL and include "png.h" from pngasmrd.h
    471   Made several minor corrections to pngtest.c
    472   Renamed the makefiles with longer but more user friendly extensions.
    473   Copied the PNG copyright and license to a separate LICENSE file.
    474   Revised documentation, png.h, and example.c to remove reference to
    475     "viewing_gamma" which no longer appears in the PNG specification.
    476   Revised pngvcrd.c to use MMX code for interlacing only on the final pass.
    477   Updated pngvcrd.c to use the faster C filter algorithms from libpng-1.0.1a
    478   Split makefile.win32vc into two versions, makefile.vcawin32 (uses MMX
    479     assembler code) and makefile.vcwin32 (doesn't).
    480   Added a CPU timing report to pngtest.c (enabled by defining PNGTEST_TIMING)
    481   Added a copy of pngnow.png to the distribution.
    482 version 1.0.4a [September 25, 1999]
    483   Increase max_pixel_depth in pngrutil.c if a user transform needs it.
    484   Changed several division operations to right-shifts in pngvcrd.c
    485 version 1.0.4b [September 30, 1999]
    486   Added parentheses in line 3732 of pngvcrd.c
    487   Added a comment in makefile.linux warning about buggy -O3 in pgcc 2.95.1
    488 version 1.0.4c [October 1, 1999]
    489   Added a "png_check_version" function in png.c and pngtest.c that will generate
    490     a helpful compiler error if an old png.h is found in the search path.
    491   Changed type of png_user_transform_depth|channels from int to png_byte.
    492 version 1.0.4d [October 6, 1999]
    493   Changed 0.45 to 0.45455 in png_set_sRGB()
    494   Removed unused PLTE entries from pngnow.png
    495   Re-enabled some parts of pngvcrd.c (png_combine_row) that work properly.
    496 version 1.0.4e [October 10, 1999]
    497   Fixed sign error in pngvcrd.c (Greg Roelofs)
    498   Replaced some instances of memcpy with simple assignments in pngvcrd (GR-P)
    499 version 1.0.4f [October 15, 1999]
    500   Surrounded example.c code with #if 0 .. #endif to prevent people from
    501     inadvertently trying to compile it.
    502   Changed png_get_header_version() from a function to a macro in png.h
    503   Added type casting mostly in pngrtran.c and pngwtran.c
    504   Removed some pointless "ptr = NULL" in pngmem.c
    505   Added a "contrib" directory containing the source code from Greg's book.
    506 
    507 version 1.0.5 [October 15, 1999]
    508   Minor editing of the INSTALL and README files.
    509 version 1.0.5a [October 23, 1999]
    510   Added contrib/pngsuite and contrib/pngminus (Willem van Schaik)
    511   Fixed a typo in the png_set_sRGB() function call in example.c (Jan Nijtmans)
    512   Further optimization and bugfix of pngvcrd.c
    513   Revised pngset.c so that it does not allocate or free memory in the user's
    514     text_ptr structure.  Instead, it makes its own copy.
    515   Created separate write_end_info_struct in pngtest.c for a more severe test.
    516   Added code in pngwrite.c to free info_ptr->text[i].key to stop a memory leak.
    517 version 1.0.5b [November 23, 1999]
    518   Moved PNG_FLAG_HAVE_CHUNK_HEADER, PNG_FLAG_BACKGROUND_IS_GRAY and
    519     PNG_FLAG_WROTE_tIME from flags to mode.
    520   Added png_write_info_before_PLTE() function.
    521   Fixed some typecasting in contrib/gregbook/*.c
    522   Updated scripts/makevms.com and added makevms.com to contrib/gregbook
    523     and contrib/pngminus (Martin Zinser)
    524 version 1.0.5c [November 26, 1999]
    525   Moved png_get_header_version from png.h to png.c, to accommodate ansi2knr.
    526   Removed all global arrays (according to PNG_NO_GLOBAL_ARRAYS macro), to
    527     accommodate making DLL's: Moved usr_png_ver from global variable to function
    528     png_get_header_ver() in png.c.  Moved png_sig to png_sig_bytes in png.c and
    529     eliminated use of png_sig in pngwutil.c.  Moved the various png_CHNK arrays
    530     into pngtypes.h.  Eliminated use of global png_pass arrays.  Declared the
    531     png_CHNK and png_pass arrays to be "const".  Made the global arrays
    532     available to applications (although none are used in libpng itself) when
    533     PNG_NO_GLOBAL_ARRAYS is not defined or when PNG_GLOBAL_ARRAYS is defined.
    534   Removed some extraneous "-I" from contrib/pngminus/makefile.std
    535   Changed the PNG_sRGB_INTENT macros in png.h to be consistent with PNG-1.2.
    536   Change PNG_SRGB_INTENT to PNG_sRGB_INTENT in libpng.txt and libpng.3
    537 version 1.0.5d [November 29, 1999]
    538   Add type cast (png_const_charp) two places in png.c
    539   Eliminated pngtypes.h; use macros instead to declare PNG_CHNK arrays.
    540   Renamed "PNG_GLOBAL_ARRAYS" to "PNG_USE_GLOBAL_ARRAYS" and made available
    541     to applications a macro "PNG_USE_LOCAL_ARRAYS".
    542   Remove all the new declarations with #ifdef/#endif when
    543     PNG_USE_GLOBAL_ARRAYS is defined.
    544   Added PNG_EXPORT_VAR macro to accommodate making DLL's.
    545 version 1.0.5e [November 30, 1999]
    546   Added iCCP, iTXt, and sPLT support; added "lang" member to the png_text
    547     structure; refactored the inflate/deflate support to make adding new chunks
    548     with trailing compressed parts easier in the future, and added new functions
    549     png_free_iCCP, png_free_pCAL, png_free_sPLT, png_free_text, png_get_iCCP,
    550     png_get_spalettes, png_set_iCCP, png_set_spalettes (Eric S. Raymond).
    551   NOTE: Applications that write text chunks MUST define png_text->lang
    552     before calling png_set_text(). It must be set to NULL if you want to
    553     write tEXt or zTXt chunks.  If you want your application to be able to
    554     run with older versions of libpng, use
    555 
    556       #ifdef PNG_iTXt_SUPPORTED
    557          png_text[i].lang = NULL;
    558       #endif
    559 
    560   Changed png_get_oFFs() and png_set_oFFs() to use signed rather than unsigned
    561     offsets (Eric S. Raymond).
    562   Combined PNG_READ_cHNK_SUPPORTED and PNG_WRITE_cHNK_SUPPORTED macros into
    563     PNG_cHNK_SUPPORTED and combined the three types of PNG_text_SUPPORTED
    564     macros, leaving the separate macros also available.
    565   Removed comments on #endifs at the end of many short, non-nested #if-blocks.
    566 version 1.0.5f [December 6, 1999]
    567   Changed makefile.solaris to issue a warning about potential problems when
    568     the ucb "ld" is in the path ahead of the ccs "ld".
    569   Removed "- [date]" from the "synopsis" line in libpng.3 and libpngpf.3.
    570   Added sCAL chunk support (Eric S. Raymond).
    571 version 1.0.5g [December 7, 1999]
    572   Fixed "png_free_spallettes" typo in png.h
    573   Added code to handle new chunks in pngpread.c
    574   Moved PNG_CHNK string macro definitions outside of PNG_NO_EXTERN block
    575   Added "translated_key" to png_text structure and png_write_iTXt().
    576   Added code in pngwrite.c to work around a newly discovered zlib bug.
    577 version 1.0.5h [December 10, 1999]
    578   NOTE: regarding the note for version 1.0.5e, the following must also
    579     be included in your code:
    580         png_text[i].translated_key = NULL;
    581   Unknown chunk handling is now supported.
    582   Option to eliminate all floating point support was added.  Some new
    583     fixed-point functions such as png_set_gAMA_fixed() were added.
    584   Expanded tabs and removed trailing blanks in source files.
    585 version 1.0.5i [December 13, 1999]
    586   Added some type casts to silence compiler warnings.
    587   Renamed "png_free_spalette" to "png_free_spalettes" for consistency.
    588   Removed leading blanks from a #define in pngvcrd.c
    589   Added some parameters to the new png_set_keep_unknown_chunks() function.
    590   Added a test for up->location != 0 in the first instance of writing
    591     unknown chunks in pngwrite.c
    592   Changed "num" to "i" in png_free_spalettes() and png_free_unknowns() to
    593     prevent recursion.
    594   Added png_free_hIST() function.
    595   Various patches to fix bugs in the sCAL and integer cHRM processing,
    596     and to add some convenience macros for use with sCAL.
    597 version 1.0.5j [December 21, 1999]
    598   Changed "unit" parameter of png_write_sCAL from png_byte to int, to work
    599     around buggy compilers.
    600   Added new type "png_fixed_point" for integers that hold float*100000 values
    601   Restored backward compatibility of tEXt/zTXt chunk processing:
    602     Restored the first four members of png_text to the same order as v.1.0.5d.
    603     Added members "lang_key" and "itxt_length" to png_text struct.  Set
    604     text_length=0 when "text" contains iTXt data.  Use the "compression"
    605     member to distinguish among tEXt/zTXt/iTXt types.  Added
    606     PNG_ITXT_COMPRESSION_NONE (1) and PNG_ITXT_COMPRESSION_zTXt(2) macros.
    607     The "Note" above, about backward incompatibility of libpng-1.0.5e, no
    608     longer applies.
    609   Fixed png_read|write_iTXt() to read|write parameters in the right order,
    610     and to write the iTXt chunk after IDAT if it appears in the end_ptr.
    611   Added pnggccrd.c, version of pngvcrd.c Intel assembler for gcc (Greg Roelofs)
    612   Reversed the order of trying to write floating-point and fixed-point gAMA.
    613 version 1.0.5k [December 27, 1999]
    614   Added many parentheses, e.g., "if (a && b & c)" becomes "if (a && (b & c))"
    615   Added png_handle_as_unknown() function (Glenn)
    616   Added png_free_chunk_list() function and chunk_list and num_chunk_list members
    617     of png_ptr.
    618   Eliminated erroneous warnings about multiple sPLT chunks and sPLT-after-PLTE.
    619   Fixed a libpng-1.0.5h bug in pngrutil.c that was issuing erroneous warnings
    620     about ignoring incorrect gAMA with sRGB (gAMA was in fact not ignored)
    621   Added png_free_tRNS(); png_set_tRNS() now malloc's its own trans array (ESR).
    622   Define png_get_int_32 when oFFs chunk is supported as well as when pCAL is.
    623   Changed type of proflen from png_int_32 to png_uint_32 in png_get_iCCP().
    624 version 1.0.5l [January 1, 2000]
    625   Added functions png_set_read_user_chunk_fn() and png_get_user_chunk_ptr()
    626     for setting a callback function to handle unknown chunks and for
    627     retrieving the associated user pointer (Glenn).
    628 version 1.0.5m [January 7, 2000]
    629   Added high-level functions png_read_png(), png_write_png(), png_free_pixels().
    630 version 1.0.5n [January 9, 2000]
    631   Added png_free_PLTE() function, and modified png_set_PLTE() to malloc its
    632     own memory for info_ptr->palette.  This makes it safe for the calling
    633     application to free its copy of the palette any time after it calls
    634     png_set_PLTE().
    635 version 1.0.5o [January 20, 2000]
    636   Cosmetic changes only (removed some trailing blanks and TABs)
    637 version 1.0.5p [January 31, 2000]
    638   Renamed pngdll.mak to makefile.bd32
    639   Cosmetic changes in pngtest.c
    640 version 1.0.5q [February 5, 2000]
    641   Relocated the makefile.solaris warning about PATH problems.
    642   Fixed pngvcrd.c bug by pushing/popping registers in mmxsupport (Bruce Oberg)
    643   Revised makefile.gcmmx
    644   Added PNG_SETJMP_SUPPORTED, PNG_SETJMP_NOT_SUPPORTED, and PNG_ABORT() macros
    645 version 1.0.5r [February 7, 2000]
    646   Removed superfluous prototype for png_get_itxt from png.h
    647   Fixed a bug in pngrtran.c that improperly expanded the background color.
    648   Return *num_text=0 from png_get_text() when appropriate, and fix documentation
    649     of png_get_text() in libpng.txt/libpng.3.
    650 version 1.0.5s [February 18, 2000]
    651   Added "png_jmp_env()" macro to pngconf.h, to help people migrate to the
    652     new error handler that's planned for the next libpng release, and changed
    653     example.c, pngtest.c, and contrib programs to use this macro.
    654   Revised some of the DLL-export macros in pngconf.h (Greg Roelofs)
    655   Fixed a bug in png_read_png() that caused it to fail to expand some images
    656     that it should have expanded.
    657   Fixed some mistakes in the unused and undocumented INCH_CONVERSIONS functions
    658     in pngget.c
    659   Changed the allocation of palette, history, and trans arrays back to
    660     the version 1.0.5 method (linking instead of copying) which restores
    661     backward compatibility with version 1.0.5.  Added some remarks about
    662     that in example.c.  Added "free_me" member to info_ptr and png_ptr
    663     and added png_free_data() function.
    664   Updated makefile.linux and makefile.gccmmx to make directories conditionally.
    665   Made cosmetic changes to pngasmrd.h
    666   Added png_set_rows() and png_get_rows(), for use with png_read|write_png().
    667   Modified png_read_png() to allocate info_ptr->row_pointers only if it
    668     hasn't already been allocated.
    669 version 1.0.5t [March 4, 2000]
    670   Changed png_jmp_env() migration aiding macro to png_jmpbuf().
    671   Fixed "interlace" typo (should be "interlaced") in contrib/gregbook/read2-x.c
    672   Fixed bug with use of PNG_BEFORE_IHDR bit in png_ptr->mode, introduced when
    673     PNG_FLAG_HAVE_CHUNK_HEADER was moved into png_ptr->mode in version 1.0.5b
    674   Files in contrib/gregbook were revised to use png_jmpbuf() and to select
    675     a 24-bit visual if one is available, and to allow abbreviated options.
    676   Files in contrib/pngminus were revised to use the png_jmpbuf() macro.
    677   Removed spaces in makefile.linux and makefile.gcmmx, introduced in 1.0.5s
    678 version 1.0.5u [March 5, 2000]
    679   Simplified the code that detects old png.h in png.c and pngtest.c
    680   Renamed png_spalette (_p, _pp) to png_sPLT_t (_tp, _tpp)
    681   Increased precision of rgb_to_gray calculations from 8 to 15 bits and
    682     added png_set_rgb_to_gray_fixed() function.
    683   Added makefile.bc32 (32-bit Borland C++, C mode)
    684 version 1.0.5v [March 11, 2000]
    685   Added some parentheses to the png_jmpbuf macro definition.
    686   Updated references to the zlib home page, which has moved to freesoftware.com.
    687   Corrected bugs in documentation regarding png_read_row() and png_write_row().
    688   Updated documentation of png_rgb_to_gray calculations in libpng.3/libpng.txt.
    689   Renamed makefile.borland,turboc3 back to makefile.bor,tc3 as in version 1.0.3,
    690     revised borland makefiles; added makefile.ibmvac3 and makefile.gcc (Cosmin)
    691 
    692 version 1.0.6 [March 20, 2000]
    693   Minor revisions of makefile.bor, libpng.txt, and gregbook/rpng2-win.c
    694   Added makefile.sggcc (SGI IRIX with gcc)
    695 version 1.0.6d [April 7, 2000]
    696   Changed sprintf() to strcpy() in png_write_sCAL_s() to work without STDIO
    697   Added data_length parameter to png_decompress_chunk() function
    698   Revised documentation to remove reference to abandoned png_free_chnk functions
    699   Fixed an error in png_rgb_to_gray_fixed()
    700   Revised example.c, usage of png_destroy_write_struct().
    701   Renamed makefile.ibmvac3 to makefile.ibmc, added libpng.icc IBM project file
    702   Added a check for info_ptr->free_me&PNG_FREE_TEXT when freeing text in png.c
    703   Simplify png_sig_bytes() function to remove use of non-ISO-C strdup().
    704 version 1.0.6e [April 9, 2000]
    705   Added png_data_freer() function.
    706   In the code that checks for over-length tRNS chunks, added check of
    707     info_ptr->num_trans as well as png_ptr->num_trans (Matthias Benckmann)
    708   Minor revisions of libpng.txt/libpng.3.
    709   Check for existing data and free it if the free_me flag is set, in png_set_*()
    710     and png_handle_*().
    711   Only define PNG_WEIGHTED_FILTERS_SUPPORTED when PNG_FLOATING_POINT_SUPPORTED
    712     is defined.
    713   Changed several instances of PNG_NO_CONSOLE_ID to PNG_NO_STDIO in pngrutil.c
    714     and mentioned the purposes of the two macros in libpng.txt/libpng.3.
    715 version 1.0.6f [April 14, 2000]
    716   Revised png_set_iCCP() and png_set_rows() to avoid prematurely freeing data.
    717   Add checks in png_set_text() for NULL members of the input text structure.
    718   Revised libpng.txt/libpng.3.
    719   Removed superfluous prototype for png_set_itxt from png.h
    720   Removed "else" from pngread.c, after png_error(), and changed "0" to "length".
    721   Changed several png_errors about malformed ancillary chunks to png_warnings.
    722 version 1.0.6g [April 24, 2000]
    723   Added png_pass-* arrays to pnggccrd.c when PNG_USE_LOCAL_ARRAYS is defined.
    724   Relocated paragraph about png_set_background() in libpng.3/libpng.txt
    725     and other revisions (Matthias Benckmann)
    726   Relocated info_ptr->free_me, png_ptr->free_me, and other info_ptr and
    727     png_ptr members to restore binary compatibility with libpng-1.0.5
    728     (breaks compatibility with libpng-1.0.6).
    729 version 1.0.6h [April 24, 2000]
    730   Changed shared library so-number pattern from 2.x.y.z to xy.z (this builds
    731     libpng.so.10 & libpng.so.10.6h instead of libpng.so.2 & libpng.so.2.1.0.6h)
    732     This is a temporary change for test purposes.
    733 version 1.0.6i [May 2, 2000]
    734   Rearranged some members at the end of png_info and png_struct, to put
    735     unknown_chunks_num and free_me within the original size of the png_structs
    736     and free_me, png_read_user_fn, and png_free_fn within the original png_info,
    737     because some old applications allocate the structs directly instead of
    738     using png_create_*().
    739   Added documentation of user memory functions in libpng.txt/libpng.3
    740   Modified png_read_png so that it will use user_allocated row_pointers
    741     if present, unless free_me directs that it be freed, and added description
    742     of the use of png_set_rows() and png_get_rows() in libpng.txt/libpng.3.
    743   Added PNG_LEGACY_SUPPORTED macro, and #ifdef out all new (since version
    744     1.00) members of png_struct and png_info, to regain binary compatibility
    745     when you define this macro.  Capabilities lost in this event
    746     are user transforms (new in version 1.0.0),the user transform pointer
    747     (new in version 1.0.2), rgb_to_gray (new in 1.0.5), iCCP, sCAL, sPLT,
    748     the high-level interface, and unknown chunks support (all new in 1.0.6).
    749     This was necessary because of old applications that allocate the structs
    750     directly as authors were instructed to do in libpng-0.88 and earlier,
    751     instead of using png_create_*().
    752   Added modes PNG_CREATED_READ_STRUCT and PNG_CREATED_WRITE_STRUCT which
    753     can be used to detect codes that directly allocate the structs, and
    754     code to check these modes in png_read_init() and png_write_init() and
    755     generate a libpng error if the modes aren't set and PNG_LEGACY_SUPPORTED
    756     was not defined.
    757   Added makefile.intel and updated makefile.watcom (Pawel Mrochen)
    758 version 1.0.6j [May 3, 2000]
    759   Overloaded png_read_init() and png_write_init() with macros that convert
    760     calls to png_read_init_2() or png_write_init_2() that check the version
    761     and structure sizes.
    762 version 1.0.7beta11 [May 7, 2000]
    763   Removed the new PNG_CREATED_READ_STRUCT and PNG_CREATED_WRITE_STRUCT modes
    764     which are no longer used.
    765   Eliminated the three new members of png_text when PNG_LEGACY_SUPPORTED is
    766     defined or when neither PNG_READ_iTXt_SUPPORTED nor PNG_WRITE_iTXT_SUPPORTED
    767     is defined.
    768   Made PNG_NO_READ|WRITE_iTXt the default setting, to avoid memory
    769     overrun when old applications fill the info_ptr->text structure directly.
    770   Added PNGAPI macro, and added it to the definitions of all exported functions.
    771   Relocated version macro definitions ahead of the includes of zlib.h and
    772     pngconf.h in png.h.
    773 version 1.0.7beta12 [May 12, 2000]
    774   Revised pngset.c to avoid a problem with expanding the png_debug macro.
    775   Deleted some extraneous defines from pngconf.h
    776   Made PNG_NO_CONSOLE_IO the default condition when PNG_BUILD_DLL is defined.
    777   Use MSC _RPTn debugging instead of fprintf if _MSC_VER is defined.
    778   Added png_access_version_number() function.
    779   Check for mask&PNG_FREE_CHNK (for TEXT, SCAL, PCAL) in png_free_data().
    780   Expanded libpng.3/libpng.txt information about png_data_freer().
    781 version 1.0.7beta14 [May 17, 2000] (beta13 was not published)
    782   Changed pnggccrd.c and pngvcrd.c to handle bad adaptive filter types as
    783     warnings instead of errors, as pngrutil.c does.
    784   Set the PNG_INFO_IDAT valid flag in png_set_rows() so png_write_png()
    785     will actually write IDATs.
    786   Made the default PNG_USE_LOCAL_ARRAYS depend on PNG_DLL instead of WIN32.
    787   Make png_free_data() ignore its final parameter except when freeing data
    788     that can have multiple instances (text, sPLT, unknowns).
    789   Fixed a new bug in png_set_rows().
    790   Removed info_ptr->valid tests from png_free_data(), as in version 1.0.5.
    791   Added png_set_invalid() function.
    792   Fixed incorrect illustrations of png_destroy_write_struct() in example.c.
    793 version 1.0.7beta15 [May 30, 2000]
    794   Revised the deliberately erroneous Linux setjmp code in pngconf.h to produce
    795     fewer error messages.
    796   Rearranged checks for Z_OK to check the most likely path first in pngpread.c
    797     and pngwutil.c.
    798   Added checks in pngtest.c for png_create_*() returning NULL, and mentioned
    799     in libpng.txt/libpng.3 the need for applications to check this.
    800   Changed names of png_default_*() functions in pngtest to pngtest_*().
    801   Changed return type of png_get_x|y_offset_*() from png_uint_32 to png_int_32.
    802   Fixed some bugs in the unused PNG_INCH_CONVERSIONS functions in pngget.c
    803   Set each pointer to NULL after freeing it in png_free_data().
    804   Worked around a problem in pngconf.h; AIX's strings.h defines an "index"
    805     macro that conflicts with libpng's png_color_16.index. (Dimitri Papadapoulos)
    806   Added "msvc" directory with MSVC++ project files (Simon-Pierre Cadieux).
    807 version 1.0.7beta16 [June 4, 2000]
    808   Revised the workaround of AIX string.h "index" bug.
    809   Added a check for overlength PLTE chunk in pngrutil.c.
    810   Added PNG_NO_POINTER_INDEXING macro to use array-indexing instead of pointer
    811     indexing in pngrutil.c and pngwutil.c to accommodate a buggy compiler.
    812   Added a warning in png_decompress_chunk() when it runs out of data, e.g.
    813     when it tries to read an erroneous PhotoShop iCCP chunk.
    814   Added PNG_USE_DLL macro.
    815   Revised the copyright/disclaimer/license notice.
    816   Added contrib/msvctest directory
    817 version 1.0.7rc1 [June 9, 2000]
    818   Corrected the definition of PNG_TRANSFORM_INVERT_ALPHA  (0x0400 not 0x0200)
    819   Added contrib/visupng directory (Willem van Schaik)
    820 version 1.0.7beta18 [June 23, 2000]
    821   Revised PNGAPI definition, and pngvcrd.c to work with __GCC__
    822     and do not redefine PNGAPI if it is passed in via a compiler directive.
    823   Revised visupng/PngFile.c to remove returns from within the Try block.
    824   Removed leading underscores from "_PNG_H" and "_PNG_SAVE_BSD_SOURCE" macros.
    825   Updated contrib/visupng/cexcept.h to version 1.0.0.
    826   Fixed bugs in pngwrite.c and pngwutil.c that prevented writing iCCP chunks.
    827 version 1.0.7rc2 [June 28, 2000]
    828   Updated license to include disclaimers required by UCITA.
    829   Fixed "DJBPP" typo in pnggccrd.c introduced in beta18.
    830 
    831 version 1.0.7 [July 1, 2000]
    832   Revised the definition of "trans_values" in libpng.3/libpng.txt
    833 version 1.0.8beta1 [July 8, 2000]
    834   Added png_free(png_ptr, key) two places in pngpread.c to stop memory leaks.
    835   Changed PNG_NO_STDIO to PNG_NO_CONSOLE_IO, several places in pngrutil.c and
    836      pngwutil.c.
    837   Changed PNG_EXPORT_VAR to use PNG_IMPEXP, in pngconf.h.
    838   Removed unused "#include <assert.h>" from png.c
    839   Added WindowsCE support.
    840   Revised pnggccrd.c to work with gcc-2.95.2 and in the Cygwin environment.
    841 version 1.0.8beta2 [July 10, 2000]
    842   Added project files to the wince directory and made further revisions
    843      of pngtest.c, pngrio.c, and pngwio.c in support of WindowsCE.
    844 version 1.0.8beta3 [July 11, 2000]
    845   Only set the PNG_FLAG_FREE_TRNS or PNG_FREE_TRNS flag in png_handle_tRNS()
    846      for indexed-color input files to avoid potential double-freeing trans array
    847      under some unusual conditions; problem was introduced in version 1.0.6f.
    848   Further revisions to pngtest.c and files in the wince subdirectory.
    849 version 1.0.8beta4 [July 14, 2000]
    850   Added the files pngbar.png and pngbar.jpg to the distribution.
    851   Added makefile.cygwin, and cygwin support in pngconf.h
    852   Added PNG_NO_ZALLOC_ZERO macro (makes png_zalloc skip zeroing memory)
    853 version 1.0.8rc1 [July 16, 2000]
    854   Revised png_debug() macros and statements to eliminate compiler warnings.
    855 
    856 version 1.0.8 [July 24, 2000]
    857   Added png_flush() in pngwrite.c, after png_write_IEND().
    858   Updated makefile.hpux to build a shared library.
    859 version 1.0.9beta1 [November 10, 2000]
    860   Fixed typo in scripts/makefile.hpux
    861   Updated makevms.com in scripts and contrib/* and contrib/* (Martin Zinser)
    862   Fixed seqence-point bug in contrib/pngminus/png2pnm (Martin Zinser)
    863   Changed "cdrom.com" in documentation to "libpng.org"
    864   Revised pnggccrd.c to get it all working, and updated makefile.gcmmx (Greg).
    865   Changed type of "params" from voidp to png_voidp in png_read|write_png().
    866   Make sure PNGAPI and PNG_IMPEXP are defined in pngconf.h.
    867   Revised the 3 instances of WRITEFILE in pngtest.c.
    868   Relocated "msvc" and "wince" project subdirectories into "dll" subdirectory.
    869   Updated png.rc in dll/msvc project
    870   Revised makefile.dec to define and use LIBPATH and INCPATH
    871   Increased size of global png_libpng_ver[] array from 12 to 18 chars.
    872   Made global png_libpng_ver[], png_sig[] and png_pass_*[] arrays const.
    873   Removed duplicate png_crc_finish() from png_handle_bKGD() function.
    874   Added a warning when application calls png_read_update_info() multiple times.
    875   Revised makefile.cygwin
    876   Fixed bugs in iCCP support in pngrutil.c and pngwutil.c.
    877   Replaced png_set_empty_plte_permitted() with png_permit_mng_features().
    878 version 1.0.9beta2 [November 19, 2000]
    879   Renamed the "dll" subdirectory "projects".
    880   Added borland project files to "projects" subdirectory.
    881   Set VS_FF_PRERELEASE and VS_FF_PATCHED flags in msvc/png.rc when appropriate.
    882   Add error message in png_set_compression_buffer_size() when malloc fails.
    883 version 1.0.9beta3 [November 23, 2000]
    884   Revised PNG_LIBPNG_BUILD_TYPE macro in png.h, used in the msvc project.
    885   Removed the png_flush() in pngwrite.c that crashes some applications
    886     that don't set png_output_flush_fn.
    887   Added makefile.macosx and makefile.aix to scripts directory.
    888 version 1.0.9beta4 [December 1, 2000]
    889   Change png_chunk_warning to png_warning in png_check_keyword().
    890   Increased the first part of msg buffer from 16 to 18 in png_chunk_error().
    891 version 1.0.9beta5 [December 15, 2000]
    892   Added support for filter method 64 (for PNG datastreams embedded in MNG).
    893 version 1.0.9beta6 [December 18, 2000]
    894   Revised png_set_filter() to accept filter method 64 when appropriate.
    895   Added new PNG_HAVE_PNG_SIGNATURE bit to png_ptr->mode and use it to
    896     help prevent applications from using MNG features in PNG datastreams.
    897   Added png_permit_mng_features() function.
    898   Revised libpng.3/libpng.txt.  Changed "filter type" to "filter method".
    899 version 1.0.9rc1 [December 23, 2000]
    900   Revised test for PNG_HAVE_PNG_SIGNATURE in pngrutil.c
    901   Fixed error handling of unknown compression type in png_decompress_chunk().
    902   In pngconf.h, define __cdecl when _MSC_VER is defined.
    903 version 1.0.9beta7 [December 28, 2000]
    904   Changed PNG_TEXT_COMPRESSION_zTXt to PNG_COMPRESSION_TYPE_BASE several places.
    905   Revised memory management in png_set_hIST and png_handle_hIST in a backward
    906     compatible manner.  PLTE and tRNS were revised similarly.
    907   Revised the iCCP chunk reader to ignore trailing garbage.
    908 version 1.0.9beta8 [January 12, 2001]
    909   Moved pngasmrd.h into pngconf.h.
    910   Improved handling of out-of-spec garbage iCCP chunks generated by PhotoShop.
    911 version 1.0.9beta9 [January 15, 2001]
    912   Added png_set_invalid, png_permit_mng_features, and png_mmx_supported to
    913     wince and msvc project module definition files.
    914   Minor revision of makefile.cygwin.
    915   Fixed bug with progressive reading of narrow interlaced images in pngpread.c
    916 version 1.0.9beta10 [January 16, 2001]
    917   Do not typedef png_FILE_p in pngconf.h when PNG_NO_STDIO is defined.
    918   Fixed "png_mmx_supported" typo in project definition files.
    919 version 1.0.9beta11 [January 19, 2001]
    920   Updated makefile.sgi to make shared library.
    921   Removed png_mmx_support() function and disabled PNG_MNG_FEATURES_SUPPORTED
    922     by default, for the benefit of DLL forward compatibility.  These will
    923     be re-enabled in version 1.2.0.
    924 version 1.0.9rc2 [January 22, 2001]
    925   Revised cygwin support.
    926 
    927 version 1.0.9 [January 31, 2001]
    928   Added check of cygwin's ALL_STATIC in pngconf.h
    929   Added "-nommx" parameter to contrib/gregbook/rpng2-win and rpng2-x demos.
    930 version 1.0.10beta1 [March 14, 2001]
    931   Revised makefile.dec, makefile.sgi, and makefile.sggcc; added makefile.hpgcc.
    932   Reformatted libpng.3 to eliminate bad line breaks.
    933   Added checks for _mmx_supported in the read_filter_row function of pnggccrd.c
    934   Added prototype for png_mmx_support() near the top of pnggccrd.c
    935   Moved some error checking from png_handle_IHDR to png_set_IHDR.
    936   Added PNG_NO_READ_SUPPORTED and PNG_NO_WRITE_SUPPORTED macros.
    937   Revised png_mmx_support() function in pnggccrd.c
    938   Restored version 1.0.8 PNG_WRITE_EMPTY_PLTE_SUPPORTED behavior in pngwutil.c
    939   Fixed memory leak in contrib/visupng/PngFile.c
    940   Fixed bugs in png_combine_row() in pnggccrd.c and pngvcrd.c (C version)
    941   Added warnings when retrieving or setting gamma=0.
    942   Increased the first part of msg buffer from 16 to 18 in png_chunk_warning().
    943 version 1.0.10rc1 [March 23, 2001]
    944   Changed all instances of memcpy, strcpy, and strlen to png_memcpy, png_strcpy,
    945     and png_strlen.
    946   Revised png_mmx_supported() function in pnggccrd.c to return proper value.
    947   Fixed bug in progressive reading (pngpread.c) with small images (height < 8).
    948 
    949 version 1.0.10 [March 30, 2001]
    950   Deleted extraneous space (introduced in 1.0.9) from line 42 of makefile.cygwin
    951   Added beos project files (Chris Herborth)
    952 version 1.0.11beta1 [April 3, 2001]
    953   Added type casts on several png_malloc() calls (Dimitri Papadapoulos).
    954   Removed a no-longer needed AIX work-around from pngconf.h
    955   Changed several "//" single-line comments to C-style in pnggccrd.c
    956 version 1.0.11beta2 [April 11, 2001]
    957   Removed PNGAPI from several functions whose prototypes did not have PNGAPI.
    958   Updated scripts/pngos2.def
    959 version 1.0.11beta3 [April 14, 2001]
    960   Added checking the results of many instances of png_malloc() for NULL
    961 version 1.0.11beta4 [April 20, 2001]
    962   Undid the changes from version 1.0.11beta3.  Added a check for NULL return
    963     from user's malloc_fn().
    964   Removed some useless type casts of the NULL pointer.
    965   Added makefile.netbsd
    966 
    967 version 1.0.11 [April 27, 2001]
    968   Revised makefile.netbsd
    969 version 1.0.12beta1 [May 14, 2001]
    970   Test for Windows platform in pngconf.h when including malloc.h (Emmanuel Blot)
    971   Updated makefile.cygwin and handling of Cygwin's ALL_STATIC in pngconf.h
    972   Added some never-to-be-executed code in pnggccrd.c to quiet compiler warnings.
    973   Eliminated the png_error about apps using png_read|write_init().  Instead,
    974     libpng will reallocate the png_struct and info_struct if they are too small.
    975     This retains future binary compatibility for old applications written for
    976     libpng-0.88 and earlier.
    977 version 1.2.0beta1 [May 6, 2001]
    978   Bumped DLLNUM to 2.
    979   Re-enabled PNG_MNG_FEATURES_SUPPORTED and enabled PNG_ASSEMBLER_CODE_SUPPORTED
    980     by default.
    981   Added runtime selection of MMX features.
    982   Added png_set_strip_error_numbers function and related macros.
    983 version 1.2.0beta2 [May 7, 2001]
    984   Finished merging 1.2.0beta1 with version 1.0.11
    985   Added a check for attempts to read or write PLTE in grayscale PNG datastreams.
    986 version 1.2.0beta3 [May 17, 2001]
    987   Enabled user memory function by default.
    988   Modified png_create_struct so it passes user mem_ptr to user memory allocator.
    989   Increased png_mng_features flag from png_byte to png_uint_32.
    990   Bumped shared-library (so-number) and dll-number to 3.
    991 version 1.2.0beta4 [June 23, 2001]
    992   Check for missing profile length field in iCCP chunk and free chunk_data
    993      in case of truncated iCCP chunk.
    994   Bumped shared-library number to 3 in makefile.sgi and makefile.sggcc
    995   Bumped dll-number from 2 to 3 in makefile.cygwin
    996   Revised contrib/gregbook/rpng*-x.c to avoid a memory leak and to exit cleanly
    997      if user attempts to run it on an 8-bit display.
    998   Updated contrib/gregbook
    999   Use png_malloc instead of png_zalloc to allocate palette in pngset.c
   1000   Updated makefile.ibmc
   1001   Added some typecasts to eliminate gcc 3.0 warnings.  Changed prototypes
   1002      of png_write_oFFS width and height from png_uint_32 to png_int_32.
   1003   Updated example.c
   1004   Revised prototypes for png_debug_malloc and png_debug_free in pngtest.c
   1005 version 1.2.0beta5 [August 8, 2001]
   1006   Revised contrib/gregbook
   1007   Revised makefile.gcmmx
   1008   Revised pnggccrd.c to conditionally compile some thread-unsafe code only
   1009      when PNG_THREAD_UNSAFE_OK is defined.
   1010   Added tests to prevent pngwutil.c from writing a bKGD or tRNS chunk with
   1011      value exceeding 2^bit_depth-1
   1012   Revised makefile.sgi and makefile.sggcc
   1013   Replaced calls to fprintf(stderr,...) with png_warning() in pnggccrd.c
   1014   Removed restriction that do_invert_mono only operate on 1-bit opaque files
   1015 
   1016 version 1.2.0 [September 1, 2001]
   1017   Changed a png_warning() to png_debug() in pnggccrd.c
   1018   Fixed contrib/gregbook/rpng-x.c, rpng2-x.c to avoid crash with XFreeGC().
   1019 version 1.2.1beta1 [October 19, 2001]
   1020   Revised makefile.std in contrib/pngminus
   1021   Include background_1 in png_struct regardless of gamma support.
   1022   Revised makefile.netbsd and makefile.macosx, added makefile.darwin.
   1023   Revised example.c to provide more details about using row_callback().
   1024 version 1.2.1beta2 [October 25, 2001]
   1025   Added type cast to each NULL appearing in a function call, except for
   1026     WINCE functions.
   1027   Added makefile.so9.
   1028 version 1.2.1beta3 [October 27, 2001]
   1029   Removed type casts from all NULLs.
   1030   Simplified png_create_struct_2().
   1031 version 1.2.1beta4 [November 7, 2001]
   1032   Revised png_create_info_struct() and png_creat_struct_2().
   1033   Added error message if png_write_info() was omitted.
   1034   Type cast NULLs appearing in function calls when _NO_PROTO or
   1035     PNG_TYPECAST_NULL is defined.
   1036 version 1.2.1rc1 [November 24, 2001]
   1037   Type cast NULLs appearing in function calls except when PNG_NO_TYPECAST_NULL
   1038     is defined.
   1039   Changed typecast of "size" argument to png_size_t in pngmem.c calls to
   1040     the user malloc_fn, to agree with the prototype in png.h
   1041   Added a pop/push operation to pnggccrd.c, to preserve Eflag (Maxim Sobolev)
   1042   Updated makefile.sgi to recognize LIBPATH and INCPATH.
   1043   Updated various makefiles so "make clean" does not remove previous major
   1044     version of the shared library.
   1045 version 1.2.1rc2 [December 4, 2001]
   1046   Always allocate 256-entry internal palette, hist, and trans arrays, to
   1047     avoid out-of-bounds memory reference caused by invalid PNG datastreams.
   1048   Added a check for prefix_length > data_length in iCCP chunk handler.
   1049 
   1050 version 1.2.1 [December 7, 2001]
   1051   None.
   1052 version 1.2.2beta1 [February 22, 2002]
   1053   Fixed a bug with reading the length of iCCP profiles (Larry Reeves).
   1054   Revised makefile.linux, makefile.gcmmx, and makefile.sgi to generate
   1055     libpng.a, libpng12.so (not libpng.so.3), and libpng12/png.h
   1056   Revised makefile.darwin to remove "-undefined suppress" option.
   1057   Added checks for gamma and chromaticity values over 21474.83, which exceed
   1058     the limit for PNG unsigned 32-bit integers when encoded.
   1059   Revised calls to png_create_read_struct() and png_create_write_struct()
   1060     for simpler debugging.
   1061   Revised png_zalloc() so zlib handles errors (uses PNG_FLAG_MALLOC_NULL_MEM_OK)
   1062 version 1.2.2beta2 [February 23, 2002]
   1063   Check chunk_length and idat_size for invalid (over PNG_MAX_UINT) lengths.
   1064   Check for invalid image dimensions in png_get_IHDR.
   1065   Added missing "fi;" in the install target of the SGI makefiles.
   1066   Added install-static to all makefiles that make shared libraries.
   1067   Always do gamma compensation when image is partially transparent.
   1068 version 1.2.2beta3 [March 7, 2002]
   1069   Compute background.gray and background_1.gray even when color_type is RGB
   1070     in case image gets reduced to gray later.
   1071   Modified shared-library makefiles to install pkgconfig/libpngNN.pc.
   1072   Export (with PNGAPI) png_zalloc, png_zfree, and png_handle_as_unknown
   1073   Removed unused png_write_destroy_info prototype from png.h
   1074   Eliminated incorrect use of width_mmx from pnggccrd.c in pixel_bytes == 8 case
   1075   Added install-shared target to all makefiles that make shared libraries.
   1076   Stopped a double free of palette, hist, and trans when not using free_me.
   1077   Added makefile.32sunu for Sun Ultra 32 and makefile.64sunu for Sun Ultra 64.
   1078 version 1.2.2beta4 [March 8, 2002]
   1079   Compute background.gray and background_1.gray even when color_type is RGB
   1080     in case image gets reduced to gray later (Jason Summers).
   1081   Relocated a misplaced /bin/rm in the "install-shared" makefile targets
   1082   Added PNG_1_0_X macro which can be used to build a 1.0.x-compatible library.
   1083 version 1.2.2beta5 [March 26, 2002]
   1084   Added missing PNGAPI to several function definitions.
   1085   Check for invalid bit_depth or color_type in png_get_IHDR(), and
   1086     check for missing PLTE or IHDR in png_push_read_chunk() (Matthias Clasen).
   1087   Revised iTXt support to accept NULL for lang and lang_key.
   1088   Compute gamma for color components of background even when color_type is gray.
   1089   Changed "()" to "{}" in scripts/libpng.pc.in.
   1090   Revised makefiles to put png.h and pngconf.h only in $prefix/include/libpngNN
   1091   Revised makefiles to make symlink to libpng.so.NN in addition to libpngNN.so
   1092 version 1.2.2beta6 [March 31, 2002]
   1093 version 1.0.13beta1 [March 31, 2002]
   1094   Prevent png_zalloc() from trying to memset memory that it failed to acquire.
   1095   Add typecasts of PNG_MAX_UINT in pngset_cHRM_fixed() (Matt Holgate).
   1096   Ensure that the right function (user or default) is used to free the
   1097     png_struct after an error in png_create_read_struct_2().
   1098 version 1.2.2rc1 [April 7, 2002]
   1099 version 1.0.13rc1 [April 7, 2002]
   1100   Save the ebx register in pnggccrd.c (Sami Farin)
   1101   Add "mem_ptr = png_ptr->mem_ptr" in png_destroy_write_struct() (Paul Gardner).
   1102   Updated makefiles to put headers in include/libpng and remove old include/*.h.
   1103 
   1104 version 1.2.2 [April 15, 2002]
   1105 version 1.0.13 [April 15, 2002]
   1106   Revised description of png_set_filter() in libpng.3/libpng.txt.
   1107   Revised makefile.netbsd and added makefile.neNNbsd and makefile.freebsd
   1108 version 1.0.13patch01 [April 17, 2002]
   1109 version 1.2.2patch01 [April 17, 2002]
   1110   Changed ${PNGMAJ}.${PNGVER} bug to ${PNGVER} in makefile.sgi and makefile.sggcc
   1111   Fixed VER -> PNGVER typo in makefile.macosx and added install-static to install
   1112   Added install: target to makefile.32sunu and makefile.64sunu
   1113 version 1.0.13patch03 [April 18, 2002]
   1114 version 1.2.2patch03 [April 18, 2002]
   1115   Revised 15 makefiles to link libpng.a to libpngNN.a and the include libpng
   1116   subdirectory to libpngNN subdirectory without the full pathname.
   1117   Moved generation of libpng.pc from "install" to "all" in 15 makefiles.
   1118 version 1.2.3rc1 [April 28, 2002]
   1119   Added install-man target to 15 makefiles (Dimitri Papadopolous-Orfanos).
   1120   Added $(DESTDIR) feature to 24 makefiles (Tim Mooney)
   1121   Fixed bug with $prefix, should be $(prefix) in makefile.hpux.
   1122   Updated cygwin-specific portion of pngconf.h and revised makefile.cygwin
   1123   Added a link from libpngNN.pc to libpng.pc in 15 makefiles.
   1124   Added links from include/libpngNN/*.h to include/*.h in 24 makefiles.
   1125   Revised makefile.darwin to make relative links without full pathname.
   1126   Added setjmp() at the end of png_create_*_struct_2() in case user forgets
   1127     to put one in their application.
   1128   Restored png_zalloc() and png_zfree() prototypes to version 1.2.1 and
   1129     removed them from module definition files.
   1130 version 1.2.3rc2 [May 1, 2002]
   1131   Fixed bug in reporting number of channels in pngget.c and pngset.c,
   1132     that was introduced in version 1.2.2beta5.
   1133   Exported png_zalloc(), png_zfree(), png_default_read(), png_default_write(),
   1134     png_default_flush(), and png_push_fill_buffer() and included them in
   1135     module definition files.
   1136   Added "libpng.pc" dependency to the "install-shared" target in 15 makefiles.
   1137 version 1.2.3rc3 [May 1, 2002]
   1138   Revised prototype for png_default_flush()
   1139   Remove old libpng.pc and libpngNN.pc before installing new ones.
   1140 version 1.2.3rc4 [May 2, 2002]
   1141   Typos in *.def files (png_default_read|write -> png_default_read|write_data)
   1142   In makefiles, changed rm libpng.NN.pc to rm libpngNN.pc
   1143   Added libpng-config and libpngNN-config and modified makefiles to install them.
   1144   Changed $(MANPATH) to $(DESTDIR)$(MANPATH) in makefiles
   1145   Added "Win32 DLL VB" configuration to projects/msvc/libpng.dsp
   1146 version 1.2.3rc5 [May 11, 2002]
   1147   Changed "error" and "message" in prototypes to "error_message" and
   1148     "warning_message" to avoid namespace conflict.
   1149   Revised 15 makefiles to build libpng-config from libpng-config-*.in
   1150   Once more restored png_zalloc and png_zfree to regular nonexported form.
   1151   Restored png_default_read|write_data, png_default_flush, png_read_fill_buffer
   1152     to nonexported form, but with PNGAPI, and removed them from module def files.
   1153 version 1.2.3rc6 [May 14, 2002]
   1154   Removed "PNGAPI" from png_zalloc() and png_zfree() in png.c
   1155   Changed "Gz" to "Gd" in projects/msvc/libpng.dsp and zlib.dsp.
   1156   Removed leftover libpng-config "sed" script from four makefiles.
   1157   Revised libpng-config creating script in 16 makefiles.
   1158 
   1159 version 1.2.3 [May 22, 2002]
   1160   Revised libpng-config target in makefile.cygwin.
   1161   Removed description of png_set_mem_fn() from documentation.
   1162   Revised makefile.freebsd.
   1163   Minor cosmetic changes to 15 makefiles, e.g., $(DI) = $(DESTDIR)/$(INCDIR).
   1164   Revised projects/msvc/README.txt
   1165   Changed -lpng to -lpngNN in LDFLAGS in several makefiles.
   1166 version 1.2.4beta1 [May 24, 2002]
   1167   Added libpng.pc and libpng-config to "all:" target in 16 makefiles.
   1168   Fixed bug in 16 makefiles: $(DESTDIR)/$(LIBPATH) to $(DESTDIR)$(LIBPATH)
   1169   Added missing "\" before closing double quote in makefile.gcmmx.
   1170   Plugged various memory leaks; added png_malloc_warn() and png_set_text_2()
   1171     functions.
   1172 version 1.2.4beta2 [June 25, 2002]
   1173   Plugged memory leak of png_ptr->current_text (Matt Holgate).
   1174   Check for buffer overflow before reading CRC in pngpread.c (Warwick Allison)
   1175   Added -soname to the loader flags in makefile.dec, makefile.sgi, and
   1176     makefile.sggcc.
   1177   Added "test-installed" target to makefile.linux, makefile.gcmmx,
   1178     makefile.sgi, and makefile.sggcc.
   1179 version 1.2.4beta3 [June 28, 2002]
   1180   Plugged memory leak of row_buf in pngtest.c when there is a png_error().
   1181   Detect buffer overflow in pngpread.c when IDAT is corrupted with extra data.
   1182   Added "test-installed" target to makefile.32sunu, makefile.64sunu,
   1183     makefile.beos, makefile.darwin, makefile.dec, makefile.macosx,
   1184     makefile.solaris, makefile.hpux, makefile.hpgcc, and makefile.so9.
   1185 version 1.2.4rc1 and 1.0.14rc1 [July 2, 2002]
   1186   Added "test-installed" target to makefile.cygwin and makefile.sco.
   1187   Revised pnggccrd.c to be able to back out version 1.0.x via PNG_1_0_X macro.
   1188 
   1189 version 1.2.4 and 1.0.14 [July 8, 2002]
   1190   Changed png_warning() to png_error() when width is too large to process.
   1191 version 1.2.4patch01 [July 20, 2002]
   1192   Revised makefile.cygwin to use DLL number 12 instead of 13.
   1193 version 1.2.5beta1 [August 6, 2002]
   1194   Added code to contrib/gregbook/readpng2.c to ignore unused chunks.
   1195   Replaced toucan.png in contrib/gregbook (it has been corrupt since 1.0.11)
   1196   Removed some stray *.o files from contrib/gregbook.
   1197   Changed png_error() to png_warning() about "Too much data" in pngpread.c
   1198     and about "Extra compressed data" in pngrutil.c.
   1199   Prevent png_ptr->pass from exceeding 7 in png_push_finish_row().
   1200   Updated makefile.hpgcc
   1201   Updated png.c and pnggccrd.c handling of return from png_mmx_support()
   1202 version 1.2.5beta2 [August 15, 2002]
   1203   Only issue png_warning() about "Too much data" in pngpread.c when avail_in
   1204     is nonzero.
   1205   Updated makefiles to install a separate libpng.so.3 with its own rpath.
   1206 version 1.2.5rc1 and 1.0.15rc1 [August 24, 2002]
   1207   Revised makefiles to not remove previous minor versions of shared libraries.
   1208 version 1.2.5rc2 and 1.0.15rc2 [September 16, 2002]
   1209   Revised 13 makefiles to remove "-lz" and "-L$(ZLIBLIB)", etc., from shared
   1210     library loader directive.
   1211   Added missing "$OBJSDLL" line to makefile.gcmmx.
   1212   Added missing "; fi" to makefile.32sunu.
   1213 version 1.2.5rc3 and 1.0.15rc3 [September 18, 2002]
   1214   Revised libpng-config script.
   1215 
   1216 version 1.2.5 and 1.0.15 [October 3, 2002]
   1217   Revised makefile.macosx, makefile.darwin, makefile.hpgcc, and makefile.hpux,
   1218     and makefile.aix.
   1219   Relocated two misplaced PNGAPI lines in pngtest.c
   1220 version 1.2.6beta1 [October 22, 2002]
   1221   Commented out warning about uninitialized mmx_support in pnggccrd.c.
   1222   Changed "IBMCPP__" flag to "__IBMCPP__" in pngconf.h.
   1223   Relocated two more misplaced PNGAPI lines in pngtest.c
   1224   Fixed memory overrun bug in png_do_read_filler() with 16-bit datastreams,
   1225     introduced in version 1.0.2.
   1226   Revised makefile.macosx, makefile.dec, makefile.aix, and makefile.32sunu.
   1227 version 1.2.6beta2 [November 1, 2002]
   1228   Added libpng-config "--ldopts" output.
   1229   Added "AR=ar" and "ARFLAGS=rc" and changed "ar rc" to "$(AR) $(ARFLAGS)"
   1230     in makefiles.
   1231 version 1.2.6beta3 [July 18, 2004]
   1232   Reverted makefile changes from version 1.2.6beta2 and some of the changes
   1233     from version 1.2.6beta1; these will be postponed until version 1.2.7.
   1234     Version 1.2.6 is going to be a simple bugfix release.
   1235   Changed the one instance of "ln -sf" to "ln -f -s" in each Sun makefile.
   1236   Fixed potential overrun in pngerror.c by using strncpy instead of memcpy.
   1237   Added "#!/bin/sh" at the top of configure, for recognition of the
   1238     'x' flag under Cygwin (Cosmin).
   1239   Optimized vacuous tests that silence compiler warnings, in png.c (Cosmin).
   1240   Added support for PNG_USER_CONFIG, in pngconf.h (Cosmin).
   1241   Fixed the special memory handler for Borland C under DOS, in pngmem.c
   1242     (Cosmin).
   1243   Removed some spurious assignments in pngrutil.c (Cosmin).
   1244   Replaced 65536 with 65536L, and 0xffff with 0xffffL, to silence warnings
   1245     on 16-bit platforms (Cosmin).
   1246   Enclosed shift op expressions in parentheses, to silence warnings (Cosmin).
   1247   Used proper type png_fixed_point, to avoid problems on 16-bit platforms,
   1248     in png_handle_sRGB() (Cosmin).
   1249   Added compression_type to png_struct, and optimized the window size
   1250     inside the deflate stream (Cosmin).
   1251   Fixed definition of isnonalpha(), in pngerror.c and pngrutil.c (Cosmin).
   1252   Fixed handling of unknown chunks that come after IDAT (Cosmin).
   1253   Allowed png_error() and png_warning() to work even if png_ptr == NULL
   1254     (Cosmin).
   1255   Replaced row_info->rowbytes with row_bytes in png_write_find_filter()
   1256     (Cosmin).
   1257   Fixed definition of PNG_LIBPNG_VER_DLLNUM (Simon-Pierre).
   1258   Used PNG_LIBPNG_VER and PNG_LIBPNG_VER_STRING instead of the hardcoded
   1259     values in png.c (Simon-Pierre, Cosmin).
   1260   Initialized png_libpng_ver[] with PNG_LIBPNG_VER_STRING (Simon-Pierre).
   1261   Replaced PNG_LIBPNG_VER_MAJOR with PNG_LIBPNG_VER_DLLNUM in png.rc
   1262     (Simon-Pierre).
   1263   Moved the definition of PNG_HEADER_VERSION_STRING near the definitions
   1264     of the other PNG_LIBPNG_VER_... symbols in png.h (Cosmin).
   1265   Relocated #ifndef PNGAPI guards in pngconf.h (Simon-Pierre, Cosmin).
   1266   Updated scripts/makefile.vc(a)win32 (Cosmin).
   1267   Updated the MSVC project (Simon-Pierre, Cosmin).
   1268   Updated the Borland C++ Builder project (Cosmin).
   1269   Avoided access to asm_flags in pngvcrd.c, if PNG_1_0_X is defined (Cosmin).
   1270   Commented out warning about uninitialized mmx_support in pngvcrd.c (Cosmin).
   1271   Removed scripts/makefile.bd32 and scripts/pngdef.pas (Cosmin).
   1272   Added extra guard around inclusion of Turbo C memory headers, in pngconf.h
   1273     (Cosmin).
   1274   Renamed projects/msvc/ to projects/visualc6/, and projects/borland/ to
   1275     projects/cbuilder5/ (Cosmin).
   1276   Moved projects/visualc6/png32ms.def to scripts/pngw32.def,
   1277     and projects/visualc6/png.rc to scripts/pngw32.rc (Cosmin).
   1278   Added projects/visualc6/pngtest.dsp; removed contrib/msvctest/ (Cosmin).
   1279   Changed line endings to DOS style in cbuilder5 and visualc6 files, even
   1280     in the tar.* distributions (Cosmin).
   1281   Updated contrib/visupng/VisualPng.dsp (Cosmin).
   1282   Updated contrib/visupng/cexcept.h to version 2.0.0 (Cosmin).
   1283   Added a separate distribution with "configure" and supporting files (Junichi).
   1284 version 1.2.6beta4 [July 28, 2004]
   1285   Added user ability to change png_size_t via a PNG_SIZE_T macro.
   1286   Added png_sizeof() and png_convert_size() functions.
   1287   Added PNG_SIZE_MAX (maximum value of a png_size_t variable.
   1288   Added check in png_malloc_default() for (size_t)size != (png_uint_32)size
   1289     which would indicate an overflow.
   1290   Changed sPLT failure action from png_error to png_warning and abandon chunk.
   1291   Changed sCAL and iCCP failures from png_error to png_warning and abandon.
   1292   Added png_get_uint_31(png_ptr, buf) function.
   1293   Added PNG_UINT_32_MAX macro.
   1294   Renamed PNG_MAX_UINT to PNG_UINT_31_MAX.
   1295   Made png_zalloc() issue a png_warning and return NULL on potential
   1296     overflow.
   1297   Turn on PNG_NO_ZALLOC_ZERO by default in version 1.2.x
   1298   Revised "clobber list" in pnggccrd.c so it will compile under gcc-3.4.
   1299   Revised Borland portion of png_malloc() to return NULL or issue
   1300     png_error() according to setting of PNG_FLAG_MALLOC_NULL_MEM_OK.
   1301   Added PNG_NO_SEQUENTIAL_READ_SUPPORTED macro to conditionally remove
   1302     sequential read support.
   1303   Added some "#if PNG_WRITE_SUPPORTED" blocks.
   1304   Removed some redundancy with #ifdef/#endif in png_malloc_default().
   1305   Use png_malloc instead of png_zalloc to allocate the pallete.
   1306 version 1.0.16rc1 and 1.2.6rc1 [August 4, 2004]
   1307   Fixed buffer overflow vulnerability in png_handle_tRNS()
   1308   Fixed integer arithmetic overflow vulnerability in png_read_png().
   1309   Fixed some harmless bugs in png_handle_sBIT, etc, that would cause
   1310     duplicate chunk types to go undetected.
   1311   Fixed some timestamps in the -config version
   1312   Rearranged order of processing of color types in png_handle_tRNS().
   1313   Added ROWBYTES macro to calculate rowbytes without integer overflow.
   1314   Updated makefile.darwin and removed makefile.macosx from scripts directory.
   1315   Imposed default one million column, one-million row limits on the image
   1316     dimensions, and added png_set_user_limits() function to override them.
   1317   Revised use of PNG_SET_USER_LIMITS_SUPPORTED macro.
   1318   Fixed wrong cast of returns from png_get_user_width|height_max().
   1319   Changed some "keep the compiler happy" from empty statements to returns,
   1320   Revised libpng.txt to remove 1.2.x stuff from the 1.0.x distribution
   1321 version 1.0.16rc2 and 1.2.6rc2 [August 7, 2004]
   1322   Revised makefile.darwin and makefile.solaris.  Removed makefile.macosx.
   1323   Revised pngtest's png_debug_malloc() to use png_malloc() instead of
   1324     png_malloc_default() which is not supposed to be exported.
   1325   Fixed off-by-one error in one of the conversions to PNG_ROWBYTES() in
   1326     pngpread.c.  Bug was introduced in 1.2.6rc1.
   1327   Fixed bug in RGB to RGBX transformation introduced in 1.2.6rc1.
   1328   Fixed old bug in RGB to Gray transformation.
   1329   Fixed problem with 64-bit compilers by casting arguments to abs()
   1330     to png_int_32.
   1331   Changed "ln -sf" to "ln -f -s" in three makefiles (solaris, sco, so9).
   1332   Changed "HANDLE_CHUNK_*" to "PNG_HANDLE_CHUNK_*" (Cosmin)
   1333   Added "-@/bin/rm -f $(DL)/$(LIBNAME).so.$(PNGMAJ)" to 15 *NIX makefiles.
   1334   Added code to update the row_info->colortype in png_do_read_filler() (MSB).
   1335 version 1.0.16rc3 and 1.2.6rc3 [August 9, 2004]
   1336   Eliminated use of "abs()" in testing cHRM and gAMA values, to avoid
   1337     trouble with some 64-bit compilers.  Created PNG_OUT_OF_RANGE() macro.
   1338   Revised documentation of png_set_keep_unknown_chunks().
   1339   Check handle_as_unknown status in pngpread.c, as in pngread.c previously.
   1340   Moved  "PNG_HANDLE_CHUNK_*" macros out of PNG_INTERNAL section of png.h
   1341   Added "rim" definitions for CONST4 and CONST6 in pnggccrd.c
   1342 version 1.0.16rc4 and 1.2.6rc4 [August 10, 2004]
   1343   Fixed mistake in pngtest.c introduced in 1.2.6rc2 (declaration of
   1344     "pinfo" was out of place).
   1345 version 1.0.16rc5 and 1.2.6rc5 [August 10, 2004]
   1346   Moved  "PNG_HANDLE_CHUNK_*" macros out of PNG_ASSEMBLER_CODE_SUPPORTED
   1347      section of png.h where they were inadvertently placed in version rc3.
   1348 
   1349 version 1.2.6 and 1.0.16 [August 15, 2004]
   1350   Revised pngtest so memory allocation testing is only done when PNG_DEBUG==1.
   1351 version 1.2.7beta1 [August 26, 2004]
   1352   Removed unused pngasmrd.h file.
   1353   Removed references to uu.net for archived files.  Added references to
   1354     PNG Spec (second edition) and the PNG ISO/IEC Standard.
   1355   Added "test-dd" target in 15 makefiles, to run pngtest in DESTDIR.
   1356   Fixed bug with "optimized window size" in the IDAT datastream, that
   1357     causes libpng to write PNG files with incorrect zlib header bytes.
   1358 version 1.2.7beta2 [August 28, 2004]
   1359   Fixed bug with sCAL chunk and big-endian machines (David Munro).
   1360   Undid new code added in 1.2.6rc2 to update the color_type in
   1361     png_set_filler().
   1362   Added png_set_add_alpha() that updates color type.
   1363 version 1.0.17rc1 and 1.2.7rc1 [September 4, 2004]
   1364   Revised png_set_strip_filler() to not remove alpha if color_type has alpha.
   1365 
   1366 version 1.2.7 and 1.0.17 [September 12, 2004]
   1367   Added makefile.hp64
   1368   Changed projects/msvc/png32ms.def to scripts/png32ms.def in makefile.cygwin
   1369 version 1.2.8beta1 [November 1, 2004]
   1370   Fixed bug in png_text_compress() that would fail to complete a large block.
   1371   Fixed bug, introduced in libpng-1.2.7, that overruns a buffer during
   1372     strip alpha operation in png_do_strip_filler().
   1373   Added PNG_1_2_X definition in pngconf.h
   1374   Comment out with #ifdef/#endif png_info_init in png.c and png_read_init
   1375     in pngread.c (as of 1.3.0)
   1376 version 1.2.8beta2 [November 2, 2004]
   1377   Reduce color_type to a nonalpha type after strip alpha operation in
   1378     png_do_strip_filler().
   1379 version 1.2.8beta3 [November 3, 2004]
   1380   Revised definitions of PNG_MAX_UINT_32, PNG_MAX_SIZE, and PNG_MAXSUM
   1381 version 1.2.8beta4 [November 12, 2004]
   1382   Fixed (again) definition of PNG_LIBPNG_VER_DLLNUM in png.h (Cosmin).
   1383   Added PNG_LIBPNG_BUILD_PRIVATE in png.h (Cosmin).
   1384   Set png_ptr->zstream.data_type to Z_BINARY, to avoid unnecessary detection
   1385     of data type in deflate (Cosmin).
   1386   Deprecated but continue to support SPECIALBUILD and PRIVATEBUILD in favor of
   1387     PNG_LIBPNG_BUILD_SPECIAL_STRING and PNG_LIBPNG_BUILD_PRIVATE_STRING.
   1388 version 1.2.8beta5 [November 20, 2004]
   1389   Use png_ptr->flags instead of png_ptr->transformations to pass
   1390     PNG_STRIP_ALPHA info to png_do_strip_filler(), to preserve ABI
   1391     compatibility.
   1392   Revised handling of SPECIALBUILD, PRIVATEBUILD,
   1393     PNG_LIBPNG_BUILD_SPECIAL_STRING and PNG_LIBPNG_BUILD_PRIVATE_STRING.
   1394 version 1.2.8rc1 [November 24, 2004]
   1395   Moved handling of BUILD macros from pngconf.h to png.h
   1396   Added definition of PNG_LIBPNG_BASE_TYPE in png.h, inadvertently
   1397     omitted from beta5.
   1398   Revised scripts/pngw32.rc
   1399   Despammed mailing addresses by masking "@" with "at".
   1400   Inadvertently installed a supposedly faster test version of pngrutil.c
   1401 version 1.2.8rc2 [November 26, 2004]
   1402   Added two missing "\" in png.h
   1403   Change tests in pngread.c and pngpread.c to
   1404     if (png_ptr->transformations || (png_ptr->flags&PNG_FLAG_STRIP_ALPHA))
   1405        png_do_read_transformations(png_ptr);
   1406 version 1.2.8rc3 [November 28, 2004]
   1407   Reverted pngrutil.c to version libpng-1.2.8beta5.
   1408   Added scripts/makefile.elf with supporting code in pngconf.h for symbol
   1409     versioning (John Bowler).
   1410 version 1.2.8rc4 [November 29, 2004]
   1411   Added projects/visualc7 (Simon-pierre).
   1412 version 1.2.8rc5 [November 29, 2004]
   1413   Fixed new typo in scripts/pngw32.rc
   1414 
   1415 version 1.2.8 [December 3, 2004]
   1416   Removed projects/visualc7, added projects/visualc71.
   1417 
   1418 version 1.2.9beta1 [February 21, 2006]
   1419 
   1420   Initialized some structure members in pngwutil.c to avoid gcc-4.0.0 complaints
   1421   Revised man page and libpng.txt to make it clear that one should not call
   1422     png_read_end or png_write_end after png_read_png or png_write_png.
   1423   Updated references to png-mng-implement mailing list.
   1424   Fixed an incorrect typecast in pngrutil.c
   1425   Added PNG_NO_READ_SUPPORTED conditional for making a write-only library.
   1426   Added PNG_NO_WRITE_INTERLACING_SUPPORTED conditional.
   1427   Optimized alpha-inversion loops in pngwtran.c
   1428   Moved test for nonzero gamma outside of png_build_gamma_table() in pngrtran.c
   1429   Make sure num_trans is <= 256 before copying data in png_set_tRNS().
   1430   Make sure num_palette is <= 256 before copying data in png_set_PLTE().
   1431   Interchanged order of write_swap_alpha and write_invert_alpha transforms.
   1432   Added parentheses in the definition of PNG_LIBPNG_BUILD_TYPE (Cosmin).
   1433   Optimized zlib window flag (CINFO) in contrib/pngsuite/*.png (Cosmin).
   1434   Updated scripts/makefile.bc32 for Borland C++ 5.6 (Cosmin).
   1435   Exported png_get_uint_32, png_save_uint_32, png_get_uint_16, png_save_uint_16,
   1436     png_get_int_32, png_save_int_32, png_get_uint_31 (Cosmin).
   1437   Added type cast (png_byte) in png_write_sCAL() (Cosmin).
   1438   Fixed scripts/makefile.cygwin (Christian Biesinger, Cosmin).
   1439   Default iTXt support was inadvertently enabled.
   1440 
   1441 version 1.2.9beta2 [February 21, 2006]
   1442 
   1443   Check for png_rgb_to_gray and png_gray_to_rgb read transformations before
   1444     checking for png_read_dither in pngrtran.c
   1445   Revised checking of chromaticity limits to accommodate extended RGB
   1446     colorspace (John Denker).
   1447   Changed line endings in some of the project files to CRLF, even in the
   1448     "Unix" tar distributions (Cosmin).
   1449   Made png_get_int_32 and png_save_int_32 always available (Cosmin).
   1450   Updated scripts/pngos2.def, scripts/pngw32.def and projects/wince/png32ce.def
   1451     with the newly exported functions.
   1452   Eliminated distributions without the "configure" script.
   1453   Updated INSTALL instructions.
   1454 
   1455 version 1.2.9beta3 [February 24, 2006]
   1456 
   1457   Fixed CRCRLF line endings in contrib/visupng/VisualPng.dsp
   1458   Made libpng.pc respect EXEC_PREFIX (D. P. Kreil, J. Bowler)
   1459   Removed reference to pngasmrd.h from Makefile.am
   1460   Renamed CHANGES to ChangeLog.
   1461   Renamed LICENSE to COPYING.
   1462   Renamed ANNOUNCE to NEWS.
   1463   Created AUTHORS file.
   1464 
   1465 version 1.2.9beta4 [March 3, 2006]
   1466 
   1467   Changed definition of PKGCONFIG from $prefix/lib to $libdir in configure.ac
   1468   Reverted to filenames LICENSE and ANNOUNCE; removed AUTHORS and COPYING.
   1469   Removed newline from the end of some error and warning messages.
   1470   Removed test for sqrt() from configure.ac and configure.
   1471   Made swap tables in pngtrans.c PNG_CONST (Carlo Bramix).
   1472   Disabled default iTXt support that was inadvertently enabled in
   1473     libpng-1.2.9beta1.
   1474   Added "OS2" to list of systems that don't need underscores, in pnggccrd.c
   1475   Removed libpng version and date from *.c files.
   1476 
   1477 version 1.2.9beta5 [March 4, 2006]
   1478   Removed trailing blanks from source files.
   1479   Put version and date of latest change in each source file, and changed
   1480     copyright year accordingly.
   1481   More cleanup of configure.ac, Makefile.am, and associated scripts.
   1482   Restored scripts/makefile.elf which was inadvertently deleted.
   1483 
   1484 version 1.2.9beta6 [March 6, 2006]
   1485   Fixed typo (RELEASE) in configuration files.
   1486 
   1487 version 1.2.9beta7 [March 7, 2006]
   1488   Removed libpng.vers and libpng.sym from libpng12_la_SOURCES in Makefile.am
   1489   Fixed inconsistent #ifdef's around png_sig_bytes() and png_set_sCAL_s()
   1490     in png.h.
   1491   Updated makefile.elf as suggested by debian.
   1492   Made cosmetic changes to some makefiles, adding LN_SF and other macros.
   1493   Made some makefiles accept "exec_prefix".
   1494 
   1495 version 1.2.9beta8 [March 9, 2006]
   1496   Fixed some "#if defined (..." which should be "#if defined(..."
   1497     Bug introduced in libpng-1.2.8.
   1498   Fixed inconsistency in definition of png_default_read_data()
   1499   Restored blank that was lost from makefile.sggcc "clean" target in beta7.
   1500   Revised calculation of "current" and "major" for irix in ltmain.sh
   1501   Changed "mkdir" to "MKDIR_P" in some makefiles.
   1502   Separated PNG_EXPAND and PNG_EXPAND_tRNS.
   1503   Added png_set_expand_gray_1_2_4_to_8() and deprecated
   1504     png_set_gray_1_2_4_to_8() which also expands tRNS to alpha.
   1505 
   1506 version 1.2.9beta9 [March 10, 2006]
   1507   Include "config.h" in pngconf.h when available.
   1508   Added some checks for NULL png_ptr or NULL info_ptr (timeless)
   1509 
   1510 version 1.2.9beta10 [March 20, 2006]
   1511   Removed extra CR from contrib/visualpng/VisualPng.dsw (Cosmin)
   1512   Made pnggccrd.c PIC-compliant (Christian Aichinger).
   1513   Added makefile.mingw (Wolfgang Glas).
   1514   Revised pngconf.h MMX checking.
   1515 
   1516 version 1.2.9beta11 [March 22, 2006]
   1517   Fixed out-of-order declaration in pngwrite.c that was introduced in beta9
   1518   Simplified some makefiles by using LIBSO, LIBSOMAJ, and LIBSOVER macros.
   1519 
   1520 version 1.2.9rc1 [March 31, 2006]
   1521   Defined PNG_USER_PRIVATEBUILD when including "pngusr.h" (Cosmin).
   1522   Removed nonsensical assertion check from pngtest.c (Cosmin).
   1523 
   1524 version 1.2.9 [April 14, 2006]
   1525   Revised makefile.beos and added "none" selector in ltmain.sh
   1526 
   1527 version 1.2.10beta1 [April 15, 2006]
   1528   Renamed "config.h" to "png_conf.h" and revised Makefile.am to add
   1529     -DPNG_BUILDING_LIBPNG to compile directive, and modified pngconf.h
   1530     to include png_conf.h only when PNG_BUILDING_LIBPNG is defined.
   1531 
   1532 version 1.2.10beta2 [April 15, 2006]
   1533   Manually updated Makefile.in and configure.  Changed png_conf.h.in
   1534     back to config.h.
   1535 
   1536 version 1.2.10beta3 [April 15, 2006]
   1537   Change png_conf.h back to config.h in pngconf.h.
   1538 
   1539 version 1.2.10beta4 [April 16, 2006]
   1540   Change PNG_BUILDING_LIBPNG to PNG_CONFIGURE_LIBPNG in config/Makefile*.
   1541 
   1542 version 1.2.10beta5 [April 16, 2006]
   1543   Added a configure check for compiling assembler code in pnggccrd.c
   1544 
   1545 version 1.2.10beta6 [April 17, 2006]
   1546   Revised the configure check for pnggccrd.c
   1547   Moved -DPNG_CONFIGURE_LIBPNG into @LIBPNG_DEFINES@
   1548   Added @LIBPNG_DEFINES@ to arguments when building libpng.sym
   1549 
   1550 version 1.2.10beta7 [April 18, 2006]
   1551   Change "exec_prefix=$prefix" to "exec_prefix=$(prefix)" in makefiles.
   1552 
   1553 version 1.2.10rc1 [April 19, 2006]
   1554   Ensure pngconf.h doesn't define both PNG_USE_PNGGCCRD and PNG_USE_PNGVCRD
   1555   Fixed "LN_FS" typo in makefile.sco and makefile.solaris.
   1556 
   1557 version 1.2.10rc2 [April 20, 2006]
   1558   Added a backslash between -DPNG_CONFIGURE_LIBPNG and -DPNG_NO_ASSEMBLER_CODE
   1559    in configure.ac and configure
   1560   Made the configure warning about versioned symbols less arrogant.
   1561 
   1562 version 1.2.10rc3 [April 21, 2006]
   1563   Added a note in libpng.txt that png_set_sig_bytes(8) can be used when
   1564     writing an embedded PNG without the 8-byte signature.
   1565   Revised makefiles and configure to avoid making links to libpng.so.*
   1566 
   1567 version 1.2.10 [April 23, 2006]
   1568   Reverted configure to "rc2" state.
   1569 
   1570 version 1.2.11beta1 [May 31, 2006]
   1571   scripts/libpng.pc.in contained "configure" style version info and would
   1572     not work with makefiles.
   1573   The shared-library makefiles were linking to libpng.so.0 instead of
   1574     libpng.so.3 compatibility as the library.
   1575 
   1576 version 1.2.11beta2 [June 2, 2006]
   1577   Increased sprintf buffer from 50 to 52 chars in pngrutil.c to avoid
   1578     buffer overflow.
   1579   Fixed bug in example.c (png_set_palette_rgb -> png_set_palette_to_rgb)
   1580 
   1581 version 1.2.11beta3 [June 5, 2006]
   1582   Prepended "#! /bin/sh" to ltmail.sh and contrib/pngminus/*.sh (Cosmin).
   1583   Removed the accidental leftover Makefile.in~ (Cosmin).
   1584   Avoided potential buffer overflow and optimized buffer in
   1585     png_write_sCAL(), png_write_sCAL_s() (Cosmin).
   1586   Removed the include directories and libraries from CFLAGS and LDFLAGS
   1587     in scripts/makefile.gcc (Nelson A. de Oliveira, Cosmin).
   1588 
   1589 version 1.2.11beta4 [June 6, 2006]
   1590   Allow zero-length IDAT chunks after the entire zlib datastream, but not
   1591     after another intervening chunk type.
   1592 
   1593 version 1.0.19rc1, 1.2.11rc1 [June 13, 2006]
   1594   Deleted extraneous square brackets from [config.h] in configure.ac
   1595 
   1596 version 1.0.19rc2, 1.2.11rc2 [June 14, 2006]
   1597   Added prototypes for PNG_INCH_CONVERSIONS functions to png.h
   1598   Revised INSTALL and autogen.sh
   1599   Fixed typo in several makefiles (-W1 should be -Wl)
   1600   Added typedef for png_int_32 and png_uint_32 on 64-bit systems.
   1601 
   1602 version 1.0.19rc3, 1.2.11rc3 [June 15, 2006]
   1603   Removed the new typedefs for 64-bit systems (delay until version 1.4.0)
   1604   Added one zero element to png_gamma_shift[] array in pngrtran.c to avoid
   1605     reading out of bounds.
   1606 
   1607 version 1.0.19rc4, 1.2.11rc4 [June 15, 2006]
   1608   Really removed the new typedefs for 64-bit systems.
   1609 
   1610 version 1.0.19rc5, 1.2.11rc5 [June 22, 2006]
   1611   Removed png_sig_bytes entry from scripts/pngw32.def
   1612 
   1613 version 1.0.19, 1.2.11 [June 26, 2006]
   1614   None.
   1615 
   1616 version 1.0.20, 1.2.12 [June 27, 2006]
   1617   Really increased sprintf buffer from 50 to 52 chars in pngrutil.c to avoid
   1618     buffer overflow.
   1619 
   1620 version 1.2.13beta1 [October 2, 2006]
   1621   Removed AC_FUNC_MALLOC from configure.ac
   1622   Work around Intel-Mac compiler bug by setting PNG_NO_MMX_CODE in pngconf.h
   1623   Change "logical" to "bitwise" throughout documentation.
   1624   Detect and fix attempt to write wrong iCCP profile length.
   1625 
   1626 version 1.0.21, 1.2.13 [November 14, 2006]
   1627   Fix potential buffer overflow in sPLT chunk handler.
   1628   Fix Makefile.am to not try to link to noexistent files.
   1629   Check all exported functions for NULL png_ptr.
   1630 
   1631 version 1.2.14beta1 [November 17, 2006]
   1632   Relocated three misplaced tests for NULL png_ptr.
   1633   Built Makefile.in with automake-1.9.6 instead of 1.9.2.
   1634   Build configure with autoconf-2.60 instead of 2.59
   1635 
   1636 version 1.2.14beta2 [November 17, 2006]
   1637   Added some typecasts in png_zalloc().
   1638 
   1639 version 1.2.14rc1 [November 20, 2006]
   1640   Changed "strtod" to "png_strtod" in pngrutil.c
   1641 
   1642 version 1.0.22, 1.2.14    [November 27, 2006]
   1643   Added missing "$(srcdir)" in Makefile.am and Makefile.in
   1644 
   1645 version 1.2.15beta1 [December 3, 2006]
   1646   Generated configure with autoconf-2.61 instead of 2.60
   1647   Revised configure.ac to update libpng.pc and libpng-config.
   1648 
   1649 version 1.2.15beta2 [December 3, 2006]
   1650   Always export MMX asm functions, just stubs if not building pnggccrd.c
   1651 
   1652 version 1.2.15beta3 [December 4, 2006]
   1653   Add "png_bytep" typecast to profile while calculating length in pngwutil.c
   1654 
   1655 version 1.2.15beta4 [December 7, 2006]
   1656   Added scripts/CMakeLists.txt
   1657   Changed PNG_NO_ASSEMBLER_CODE to PNG_NO_MMX_CODE in scripts, like 1.4.0beta
   1658 
   1659 version 1.2.15beta5 [December 7, 2006]
   1660   Changed some instances of PNG_ASSEMBLER_* to PNG_MMX_* in pnggccrd.c
   1661   Revised scripts/CMakeLists.txt
   1662 
   1663 version 1.2.15beta6 [December 13, 2006]
   1664   Revised scripts/CMakeLists.txt and configure.ac
   1665 
   1666 version 1.2.15rc1 [December 18, 2006]
   1667   Revised scripts/CMakeLists.txt
   1668 
   1669 version 1.2.15rc2 [December 21, 2006]
   1670   Added conditional #undef jmpbuf in pngtest.c to undo #define in AIX headers.
   1671   Added scripts/makefile.nommx
   1672 
   1673 version 1.2.15rc3 [December 25, 2006]
   1674   Fixed shared library numbering error that was introduced in 1.2.15beta6.
   1675 
   1676 version 1.2.15rc4 [December 27, 2006]
   1677   Fixed handling of rgb_to_gray when png_ptr->color.gray isn't set.
   1678 
   1679 version 1.2.15rc5 [December 31, 2006]
   1680   Revised handling of rgb_to_gray.
   1681 
   1682 version 1.0.23, 1.2.15 [January 5, 2007]
   1683   Added some (unsigned long) typecasts in pngtest.c to avoid printing errors.
   1684 
   1685 version 1.2.16beta1 [January 6, 2007]
   1686   Fix bugs in makefile.nommx
   1687 
   1688 version 1.2.16beta2 [January 16, 2007]
   1689   Revised scripts/CMakeLists.txt
   1690 
   1691 version 1.0.24, 1.2.16 [January 31, 2007]
   1692   No changes.
   1693 
   1694 version 1.2.17beta1 [March 6, 2007]
   1695   Revised scripts/CMakeLists.txt to install both shared and static libraries.
   1696   Deleted a redundant line from pngset.c.
   1697 
   1698 version 1.2.17beta2 [April 26, 2007]
   1699   Relocated misplaced test for png_ptr == NULL in pngpread.c
   1700   Change "==" to "&" for testing PNG_RGB_TO_GRAY_ERR & PNG_RGB_TO_GRAY_WARN
   1701     flags.
   1702   Changed remaining instances of PNG_ASSEMBLER_* to PNG_MMX_*
   1703   Added pngerror() when write_IHDR fails in deflateInit2().
   1704   Added "const" to some array declarations.
   1705   Mention examples of libpng usage in the libpng*.txt and libpng.3 documents.
   1706 
   1707 version 1.2.17rc1 [May 4, 2007]
   1708   No changes.
   1709 
   1710 version 1.2.17rc2 [May 8, 2007]
   1711   Moved several PNG_HAVE_* macros out of PNG_INTERNAL because applications
   1712     calling set_unknown_chunk_location() need them.
   1713   Changed transformation flag from PNG_EXPAND_tRNS to PNG_EXPAND in
   1714     png_set_expand_gray_1_2_4_to_8().
   1715   Added png_ptr->unknown_chunk to hold working unknown chunk data, so it
   1716     can be free'ed in case of error.  Revised unknown chunk handling in
   1717     pngrutil.c and pngpread.c to use this structure.
   1718 
   1719 version 1.2.17rc3 [May 8, 2007]
   1720   Revised symbol-handling in configure script.
   1721 
   1722 version 1.2.17rc4 [May 10, 2007]
   1723   Revised unknown chunk handling to avoid storing unknown critical chunks.
   1724 
   1725 version 1.0.25 [May 15, 2007]
   1726 version 1.2.17 [May 15, 2007]
   1727   Added "png_ptr->num_trans=0" before error return in png_handle_tRNS,
   1728     to eliminate a vulnerability (CVE-2007-2445, CERT VU#684664)
   1729 
   1730 version 1.0.26 [May 15, 2007]
   1731 version 1.2.18 [May 15, 2007]
   1732   Reverted the libpng-1.2.17rc3 change to symbol-handling in configure script
   1733 
   1734 version 1.2.19beta1 [May 18, 2007]
   1735   Changed "const static" to "static PNG_CONST" everywhere, mostly undoing
   1736     change of libpng-1.2.17beta2.  Changed other "const" to "PNG_CONST"
   1737   Changed some handling of unused parameters, to avoid compiler warnings.
   1738     "if (unused == NULL) return;" becomes "unused = unused".
   1739 
   1740 version 1.2.19beta2 [May 18, 2007]
   1741   Only use the valid bits of tRNS value in png_do_expand() (Brian Cartier)
   1742 
   1743 version 1.2.19beta3 [May 19, 2007]
   1744   Add some "png_byte" typecasts in png_check_keyword() and write new_key
   1745   instead of key in zTXt chunk (Kevin Ryde).
   1746 
   1747 version 1.2.19beta4 [May 21, 2007]
   1748   Add png_snprintf() function and use it in place of sprint() for improved
   1749     defense against buffer overflows.
   1750 
   1751 version 1.2.19beta5 [May 21, 2007]
   1752   Fixed png_handle_tRNS() to only use the valid bits of tRNS value.
   1753   Changed handling of more unused parameters, to avoid compiler warnings.
   1754   Removed some PNG_CONST in pngwutil.c to avoid compiler warnings.
   1755 
   1756 version 1.2.19beta6 [May 22, 2007]
   1757   Added some #ifdef PNG_MMX_CODE_SUPPORTED where needed in pngvcrd.c
   1758   Added a special "_MSC_VER" case that defines png_snprintf to _snprintf
   1759 
   1760 version 1.2.19beta7 [May 22, 2007]
   1761   Squelched png_squelch_warnings() in pnggccrd.c and added
   1762     an #ifdef PNG_MMX_CODE_SUPPORTED/#endif block around the declarations
   1763     that caused the warnings that png_squelch_warnings was squelching.
   1764 
   1765 version 1.2.19beta8 [May 22, 2007]
   1766   Removed __MMX__ from test in pngconf.h.
   1767 
   1768 version 1.2.19beta9 [May 23, 2007]
   1769   Made png_squelch_warnings() available via PNG_SQUELCH_WARNINGS macro.
   1770   Revised png_squelch_warnings() so it might work.
   1771   Updated makefile.sgcc and makefile.solaris; added makefile.solaris-x86.
   1772 
   1773 version 1.2.19beta10 [May 24, 2007]
   1774   Resquelched png_squelch_warnings(), use "__attribute__((used))" instead.
   1775 
   1776 version 1.2.19beta11 [May 28, 2007]
   1777   Return 0 from png_get_sPLT() and png_get_unknown_chunks() if png_ptr is NULL;
   1778     changed three remaining instances of png_strcpy() to png_strncpy() (David
   1779     Hill).
   1780   Make test for NULL row_buf at the beginning of png_do_read_transformations
   1781     unconditional.
   1782 
   1783 version 1.2.19beta12 [May 28, 2007]
   1784   Revised pnggccrd.c.
   1785 
   1786 version 1.2.19beta13 [June 14, 2007]
   1787   Prefer PNG_USE_PNGVCRD when _MSC_VER is defined in pngconf.h
   1788 
   1789 version 1.2.19beta14 [June 16, 2007]
   1790   Fix bug with handling of 16-bit transparency, introduced in 1.2.19beta2
   1791 
   1792 version 1.2.19beta15 [June 17, 2007]
   1793   Revised pnggccrd.c.
   1794 
   1795 version 1.2.19beta16 [June 18, 2007]
   1796   Revised pnggccrd.c again.
   1797   Updated contrib/gregbook.
   1798   Changed '#include "pnggccrd.c"' to 'include "$srcdir/pnggccrd.c"'
   1799     in configure.ac
   1800 
   1801 version 1.2.19beta17 [June 19, 2007]
   1802   Revised many of the makefiles, to set -DPNG_NO_MMX_CODE where needed
   1803     and to not use -O3 unless -DPNG_NO_MMX_CODE is also set.
   1804 
   1805 version 1.2.19beta18 [June 23, 2007]
   1806   Replaced some C++ style comments with C style comments in pnggccrd.c.
   1807   Copied optimized C code from pnggccrd.c to pngrutil.c, removed dependency
   1808     on pnggccrd.o from many makefiles.
   1809   Added sl and dylib to list of extensions be installed by Makefile.am
   1810 
   1811 version 1.2.19beta19 [June 28, 2007]
   1812   Fixed testing PNG_RGB_TO_GRAY_ERR & PNG_RGB_TO_GRAY_WARN in pngrtran.c
   1813   More cleanup of pnggccrd.c and pngvcrd.c
   1814 
   1815 version 1.2.19beta20 [June 29, 2007]
   1816   Rebuilt Makefile.in and configure using libtool-1.5.24.
   1817   Fixed typo in pnggccrd.c
   1818 
   1819 version 1.2.19beta21 [June 30, 2007]
   1820   More revision of pnggccrd.c
   1821   Added "test" target to Makefile.in and Makefile.am
   1822 
   1823 version 1.2.19beta22 [July 3, 2007]
   1824   Added info about pngrutil/pnggccrd/pngvcrd to png_get_header_version()
   1825   Fix type definition of dummy_value_a, b in pnggccrd.c
   1826 
   1827 version 1.2.19beta23 [July 10, 2007]
   1828   Revert change to type definition of dummy_value_a, b in pnggccrd.c
   1829   Make sure __PIC__ is defined in pnggccrd.c when PIC is defined.
   1830   Require gcc-4.1 or better to use PNG_HAVE_MMX_FILTER_ROW on x86_64 platforms
   1831 
   1832 version 1.2.19beta24 [July 14, 2007]
   1833   Added PNG_NO_READ_FILTER, PNG_NO_WRITE_FILTER, PNG_NO_WARNING macros.
   1834   Added contrib/pngminim to demonstrate building minimal encoder and decoder
   1835 
   1836 version 1.2.19beta25 [July 15, 2007]
   1837   Removed the new PNG_NO_READ_FILTER macro since it would make the library
   1838     unable to read valid PNG files, and filtering is at the heart of the
   1839     PNG format.
   1840 
   1841 version 1.2.19beta26 [July 16, 2007]
   1842   Changed "png_free(str)" to "png_free(png_ptr,str)" in pngrutil.c WinCE
   1843     code (Yves Piguet).  This bug was introduced in libpng-1.2.14.
   1844   Updated scripts/CMakeLists.txt
   1845   Relocated a misplaced #endif in pnggccrd.c
   1846 
   1847 version 1.2.19beta27 [July 17, 2007]
   1848   Fixed incorrect stride and number of bytes copied (was 4 instead of
   1849     6 bytes) in the cleanup loop of pnggccrd.c and pngvcrd.c for handling
   1850     the end of 48-bit interlaced rows (Glenn R-P).
   1851 
   1852 version 1.2.19beta28 [July 19, 2007]
   1853   Removed requirement for gcc-4.1 or better to use PNG_HAVE_MMX_FILTER_ROW
   1854     on x86_64 platforms
   1855   Added png_warning() in pngrutil.c for short iCCP, iTXt, sPLT, or zTXT chunks.
   1856   Revised pngtest.c so warnings are displayed regardless of PNG_NO_STDIO.
   1857 
   1858 version 1.2.19beta29 [July 20, 2007]
   1859   Fix typo in pnggccrd.c (%%eax should be %%ax in secondloop48)
   1860 
   1861 version 1.2.19beta30 [July 26, 2007]
   1862   Revised pnggccrd.c
   1863 
   1864 version 1.2.19beta31 [July 27, 2007]
   1865   Fix typos in pnggccrd.c
   1866 
   1867 version 1.0.27rc1 and 1.2.19rc1 [July 31, 2007]
   1868   Disable PNG_MMX_CODE_SUPPORTED when PNG_ASSEMBLER_CODE_SUPPORTED is off.
   1869   Enable PNG_MMX_READ_FILTER_* by default, except when gcc-3.x is being
   1870     used (they were inadvertently disabled in libpng-1.2.19beta23).
   1871   Fix some debugging statements in pnggccrd.c and pngrutil.c
   1872   Added information about disabling the MMX code in libpng documentation.
   1873 
   1874 version 1.0.27rc2 and 1.2.19rc2 [August 4, 2007]
   1875   Removed some "#if 0" blocks.
   1876   Made a global struct local in pngvcrd.c to make it thread safe.
   1877   Issue a png_error() if application attempts to transform a row tht
   1878     has not been initialized.
   1879 
   1880 version 1.0.27rc3 and 1.2.19rc3 [August 9, 2007]
   1881   Slightly revised pngvcrd.c
   1882 
   1883 version 1.0.27rc4 and 1.2.19rc4 [August 9, 2007]
   1884   Revised pnggccrd.c debugging change of rc1, which was broken.
   1885   Revised scripts/CMakeLists.txt
   1886   Change default to PNG_NO_GLOBAL_ARRAYS for MSVC.
   1887   Turn off PNG_FLAG_ROW_INIT flag when setting transforms that expand pixels.
   1888 
   1889 version 1.0.27rc5 and 1.2.19rc5 [August 10, 2007]
   1890   Fix typo (missing '"') in pnggccrd.c
   1891   Revise handling of png_strtod in recent versions of WINCE
   1892 
   1893 version 1.0.27rc6 and 1.2.19rc6 [August 15, 2007]
   1894   Fix typo (missing ',') in contrib/gregbook/readpng2.c
   1895   Undid row initialization error exit added to rc2 and rc4.
   1896 
   1897 version 1.0.27 and 1.2.19 [August 18, 2007]
   1898   Conditionally restored row initialization error exit.
   1899 
   1900 version 1.2.20beta01 [August 19, 2007]
   1901   Fixed problem with compiling pnggccrd.c on Intel-Apple platforms.
   1902   Changed png_malloc() to png_malloc_warn() in png_set_sPLT().
   1903   Added PNG_NO_ERROR_TEXT feature, with demo in contrib/pngminim
   1904   Removed define PNG_WARN_UNINITIALIZED_ROW 1 /* 0: warning; 1: error */
   1905     because it caused some trouble.
   1906 
   1907 version 1.2.20beta02 [August 20, 2007]
   1908   Avoid compiling pnggccrd.c on Intel-Apple platforms.
   1909 
   1910 version 1.2.20beta03 [August 20, 2007]
   1911   Added "/D PNG_NO_MMX_CODE" to the non-mmx builds of projects/visualc6
   1912     and visualc71.
   1913 
   1914 version 1.2.20beta04 [August 21, 2007]
   1915   Revised pngvcrd.c for improved efficiency (Steve Snyder).
   1916 
   1917 version 1.2.20rc1 [August 23, 2007]
   1918   Revised pngconf.h to set PNG_NO_MMX_CODE for gcc-3.x compilers.
   1919 
   1920 version 1.2.20rc2 [August 27, 2007]
   1921   Revised scripts/CMakeLists.txt
   1922   Revised #ifdefs to ensure one and only one of pnggccrd.c, pngvcrd.c,
   1923     or part of pngrutil.c is selected.
   1924 
   1925 version 1.2.20rc3 [August 30, 2007]
   1926   Remove a little more code in pngwutil.c when PNG_NO_WRITE_FILTER is selected.
   1927   Added /D _CRT_SECURE_NO_WARNINGS to visual6c and visualc71 projects.
   1928   Compile png_mmx_support() in png.c even when PNG_NO_MMX_CODE is defined.
   1929   Restored a "superfluous" #ifdef that was removed from 1.2.20rc2 pnggccrd.c,
   1930     breaking the png_mmx_support() function.
   1931 
   1932 version 1.2.20rc4 [September 1, 2007]
   1933   Removed Intel contributions (MMX, Optimized C).
   1934 
   1935 version 1.2.20rc5 [September 2, 2007]
   1936   Restored configure and Makefile.in to rc3 and put a snippet of code in
   1937     pnggccrd.c, to ensure configure makes the same PNG_NO_MMX_CODE selection
   1938 
   1939 version 1.2.20rc6 [September 2, 2007]
   1940   Fixed bugs in scripts/CMakeLists.txt
   1941   Removed pngvcrd.c references from msvc projects.
   1942 
   1943 version 1.0.28 and 1.2.20 [September 8, 2007]
   1944   Removed "(NO READ SUPPORT)" from png_get_header_version() string.
   1945 
   1946 version 1.2.21beta1 [September 14, 2007]
   1947   Fixed various mistakes reported by George Cook and Jeff Phillips:
   1948   logical vs bitwise NOT in pngrtran.c, bug introduced in 1.2.19rc2
   1949   16-bit cheap transparency expansion, bug introduced in 1.2.19beta2
   1950   errors with sizeof(unknown_chunk.name), bugs introduced in 1.2.19beta11
   1951   <= compare with unsigned var in pngset.c, should be ==.
   1952 
   1953 version 1.2.21beta2 [September 18, 2007]
   1954   Removed some extraneous typecasts.
   1955 
   1956 version 1.2.21rc1 [September 25, 2007]
   1957   Fixed potential out-of-bounds reads in png_handle_pCAL() and
   1958     png_handle_ztXt() ("flayer" results reported by Tavis Ormandy).
   1959 
   1960 version 1.2.21rc2 [September 26, 2007]
   1961   Fixed potential out-of-bounds reads in png_handle_sCAL(),
   1962     png_handle_iTXt(), and png_push_read_tEXt().
   1963   Remove some PNG_CONST declarations from pngwutil.c to avoid compiler warnings
   1964   Revised makefiles to update paths in libpng.pc properly.
   1965 
   1966 version 1.2.21rc3 [September 27, 2007]
   1967   Revised makefiles to update "Libs" in libpng.pc properly.
   1968 
   1969 version 1.0.29 and 1.2.21rc3 [October 4, 2007]
   1970   No changes.
   1971 
   1972 version 1.2.22beta1 [October 4, 2007]
   1973   Again, fixed logical vs bitwise NOT in pngrtran.c, bug introduced
   1974     in 1.2.19rc2
   1975 
   1976 version 1.2.22beta2 [October 5, 2007]
   1977   Fixed string length error in pngset.c (caused crashes while decoding iCCP)
   1978   Add terminating NULL after each instance of png_strncpy().
   1979 
   1980 version 1.2.22beta3 [October 6, 2007]
   1981   Fix two off-by-one terminating NULL after png_strncpy().
   1982 
   1983 version 1.2.22beta4 [October 7, 2007]
   1984   Changed some 0 to '\0'.
   1985 
   1986 version 1.0.30rc1 and 1.2.22rc1 [October 8, 2007]
   1987   No changes.
   1988 
   1989 version 1.0.30 and 1.2.22 [October 13, 2007]
   1990   No changes.
   1991 
   1992 version 1.2.23beta01 [October 15, 2007]
   1993   Reduced number of invocations of png_strlen() in pngset.c.
   1994   Changed [azAZ09_] to [_abcde...89] in Makefile.am for better localization.
   1995 
   1996 version 1.2.23beta02 [October 16, 2007]
   1997   Eliminated png_strncpy() and png_strcpy() (Pierre Poissinger)
   1998   Changed $AN to $(AN) in Makefile.am.
   1999 
   2000 version 1.2.23beta03 [October 16, 2007]
   2001   Fixed off-by-one error in pngset.c
   2002   Restore statement to set last character of buffer to \0 in pngerror.c
   2003 
   2004 version 1.2.23beta04 [October 23, 2007]
   2005   Reject attempt to set all-zero cHRM values.
   2006 
   2007 version 1.2.23beta05 [October 26, 2007]
   2008   Add missing quotes in projects/visualc6, lost in version 1.2.20rc3
   2009 
   2010 version 1.2.23rc01 [November 2, 2007]
   2011   No changes.
   2012 
   2013 version 1.2.23 [November 6, 2007]
   2014   No changes.
   2015 
   2016 version 1.2.24beta01 [November 19, 2007]
   2017   Moved misplaced test for malloc failure in png_set_sPLT().  This bug was
   2018     introduced in libpng-1.2.20beta01.
   2019   Ifdef out avg_row etc from png.h and pngwrite.c when PNG_NO_WRITE_FILTER
   2020   Do not use png_ptr->free_fn and png_ptr->mem_fn in png_destroy_read_struct()
   2021     when png_ptr is NULL (Marshall Clow).
   2022   Updated handling of symbol prefixes in Makefile.am and configure.ac (Mike
   2023     Frysinger).
   2024 
   2025 version 1.2.24beta02 [November 30, 2007]
   2026   Removed a useless test and fixed incorrect test in png_set_cHRM_fixed()
   2027     (David Hill).
   2028 
   2029 version 1.2.24rc01 [December 7, 2007]
   2030   No changes.
   2031 
   2032 version 1.2.24     [December 14, 2007]
   2033   Make sure not to redefine _BSD_SOURCE in pngconf.h
   2034   Revised gather.sh and makefile.std in contrib/pngminim to avoid compiling
   2035     unused files.
   2036 
   2037 version 1.2.25beta01 [January 7, 2008]
   2038   Fixed bug with unknown chunk handling, introduced in version 1.2.17rc2
   2039 
   2040 version 1.2.25beta02 [January 10, 2008]
   2041   Prevent gamma from being applied twice.
   2042 
   2043 version 1.2.25rc01 [January 17, 2008]
   2044   No changes.
   2045 
   2046 version 1.2.25beta03 [January 22, 2008]
   2047   Fixed some continue-after-malloc-failure errors in pngset.c (David Hill)
   2048   Check for info_ptr == NULL in png_read_info() and png_process_data().
   2049   Check for possible use of NULL user_png_ver[] in png_create_read_struct().
   2050   Change "if (swidth == NULL)" to "if (sheight == NULL)" in png_handle_sCAL
   2051     (bug introduced in libpng-1.2.4/1.0.13).
   2052   Return from png_destroy_read_struct() if png_ptr_ptr is NULL.
   2053   Fix overflow of "msg" in png_decompress_chunk().
   2054 
   2055 version 1.2.25beta04 [January 26, 2008]
   2056   Work around Coverity bug report by slightly refactoring
   2057     png_read_push_finish_row()
   2058 
   2059 version 1.2.25beta05 [January 31, 2008]
   2060   Added libpng-1.2.25beta05.tar.lzma to distribution.  Get the lzma codec
   2061     from <http://tukaani.org/lzma>.
   2062   Added lp1225b05.7z to distribution.  Get the 7-zip decoder from
   2063     from <http://www.7-zip.org>.
   2064   Fixed some broken links in the README file.
   2065 
   2066 version 1.2.25beta06 [February 6, 2008]
   2067   Refactored png_read_push_finish_row() again, trying to satisfy Coverity.
   2068   Fixed potential NULL dereference of png_ptr in png_destroy_write_struct();
   2069   clarified potential NULL dereference of png_ptr in png_destroy_read_struct();
   2070   fixed potential NULL dereference of info_ptr in png_handle_bKGD();
   2071   fixed potential NULL dereference of user_png_ver[] in
   2072     png_create_write_struct_2(). (Coverity)
   2073 
   2074 version 1.2.25rc02 [February 10, 2008]
   2075   Reset png_ptr->pass in png_read_push_finish_row() before break.
   2076   Changed "pass" from png_byte to int.
   2077 
   2078 version 1.2.25 and 1.0.31 [February 18, 2008]
   2079   No changes.
   2080 
   2081 version 1.2.26beta01 [February 21, 2008]
   2082   Added missing "(" in pngmem.c.  Bug introduced in libpng-1.2.2/1.0.13
   2083 
   2084 version 1.2.26beta02 [March 12, 2008]
   2085   Refined error message returned from deflateInit2 in pngwutil.c
   2086   Check IHDR length in png_push_read_chunk() before saving it.
   2087 
   2088 version 1.2.26beta03 [March 16, 2008]
   2089   Revised contrib/gregbook to handle premature end-of-file and file
   2090     read errors correctly.
   2091 
   2092 version 1.2.26beta04 [March 18, 2008]
   2093   Free png_ptr->big_row_buf and png_ptr->prev_row before allocating
   2094     new copies in png_read_start_row().  Bug introduced in libpng-1.2.22.
   2095 
   2096 version 1.2.26beta05 [March 19, 2008]
   2097   Removed extra png_free() added in libpng-1.2.26beta04.
   2098 
   2099 version 1.2.26beta06 [March 19, 2008]
   2100   Avoid reallocating big_row_buf and prev_row when the size does not increase.
   2101 
   2102 version 1.2.26rc01 [March 26, 2008]
   2103   Ifdef out some code that is unused when interlacing is not supported.
   2104 
   2105 versions 1.0.32 and 1.2.26 [April 2, 2008]
   2106   No changes.
   2107 
   2108 version 1.2.27beta01 [April 12, 2008]
   2109   Fixed bug (introduced in libpng-1.0.5h) with handling zero-length
   2110     unknown chunks.
   2111   Added more information about png_set_keep_unknown_chunks() to the
   2112     documentation.
   2113   Reject tRNS chunk with out-of-range samples instead of masking off
   2114     the invalid high bits as done in since libpng-1.2.19beta5.
   2115 
   2116 version 1.2.27beta02 [April 13, 2008]
   2117   Revised documentation about unknown chunk and user chunk handling.
   2118   Keep tRNS chunk with out-of-range samples and issue a png_warning().
   2119 
   2120 version 1.2.27beta03 [April 14, 2008]
   2121   Added check for NULL ptr in TURBOC version of png_free_default().
   2122   Removed several unnecessary checks for NULL before calling png_free().
   2123   Revised png_set_tRNS() so that calling it twice removes and invalidates
   2124     the previous call.
   2125   Revised pngtest to check for out-of-range tRNS samples.
   2126 
   2127 version 1.2.27beta04 [April 18, 2008]
   2128   Added AC_LIBTOOL_WIN32_DLL to configure.ac
   2129   Rebuilt Makefile.in, aclocal.m4, and configure with autoconf-2.62
   2130 
   2131 version 1.2.27beta05 [April 19, 2008]
   2132   Added MAINTAINERCLEANFILES variable to Makefile.am
   2133 
   2134 version 1.2.27beta06 [April 21, 2008]
   2135   Avoid changing color_type from GRAY to RGB by
   2136     png_set_expand_gray_1_2_4_to_8().
   2137 
   2138 version 1.2.27rc01 [April 23, 2008]
   2139   Fix broken URL for rfc2083 in png.5 and libpng-*.txt
   2140 
   2141 version 1.0.33 and 1.2.27 [April 30, 2008]
   2142   No changes.
   2143 
   2144 version 1.0.34 and 1.2.28 [April 30, 2008]
   2145   Rebuilt Makefile.in, aclocal.m4, and configure with autoconf-2.61
   2146     due to backward incompatibilities.
   2147   Removed a stray object file from contrib/gregbook
   2148 
   2149 version 1.2.29beta01 [May 1, 2008]
   2150   Removed some stray *.diff and *.orig files
   2151 
   2152 version 1.2.29beta02 [May 1, 2008]
   2153   Reverted Makefile.in, aclocal.m4, and configure to the libpng-1.2.26
   2154     versions.
   2155 
   2156 version 1.2.29beta03 [May 2, 2008]
   2157   Added --force to autogen libtoolize options and --force-missing to
   2158     automake options.
   2159   Changed $(ECHO) to echo in Makefile.am and Makefile.in
   2160   Updated all configure files to autoconf-2.62
   2161   Comment out pnggcrd.c code with #ifdef/#endif if using MSC_VER
   2162 
   2163 version 1.2.29rc01 [May 4, 2008]
   2164   No changes.
   2165 
   2166 version 1.0.35 and 1.2.29 [May 8, 2008]
   2167   No changes.
   2168 
   2169 version 1.0.37 [May 9, 2008]
   2170   Updated Makefile.in and configure (omitted version 1.0.36).
   2171 
   2172 version 1.2.30beta01 [May 29, 2008]
   2173   Updated libpng.pc-configure.in and libpng-config.in per debian bug reports.
   2174 
   2175 version 1.2.30beta02 [June 25, 2008]
   2176   Restored png_flush(png_ptr) at the end of png_write_end(), that was
   2177     removed from libpng-1.0.9beta03.
   2178 
   2179 version 1.2.30beta03 [July 6, 2008]
   2180   Merged some cosmetic whitespace changes from libpng-1.4.0beta19.
   2181   Inline call of png_get_uint_32() in png_get_uint_31(), as in 1.4.0beta19.
   2182   Added demo of decoding vpAg and sTER chunks to pngtest.c, from 1.4.0beta19.
   2183   Changed PNGMAJ from 0 to 12 in makefile.darwin, which does not like 0.
   2184   Added new private function png_read_chunk_header() from 1.4.0beta19.
   2185   Merge reading of chunk length and chunk type into a single 8-byte read.
   2186   Merge writing of chunk length and chunk type into a single 8-byte write.
   2187 
   2188 version 1.2.30beta04 [July 10, 2008]
   2189   Merged more cosmetic whitespace changes from libpng-1.4.0beta19.
   2190 
   2191 version 1.0.38rc01, 1.2.30rc01 [July 18, 2008]
   2192   No changes.
   2193 
   2194 version 1.0.38rc02, 1.2.30rc02 [July 21, 2008]
   2195   Moved local array "chunkdata" from pngrutil.c to the png_struct, so
   2196     it will be freed by png_read_destroy() in case of a read error (Kurt
   2197     Christensen).
   2198 
   2199 version 1.0.38rc03, 1.2.30rc03 [July 21, 2008]
   2200   Changed "purpose" and "buffer" to png_ptr->chunkdata to avoid memory leaking.
   2201 
   2202 version 1.0.38rc04, 1.2.30rc04 [July 22, 2008]
   2203   Changed "chunkdata = NULL" to "png_ptr->chunkdata = NULL" several places in
   2204     png_decompress_chunk().
   2205 
   2206 version 1.0.38rc05, 1.2.30rc05 [July 25, 2008]
   2207   Changed all remaining "chunkdata" to "png_ptr->chunkdata" in
   2208     png_decompress_chunk() and remove chunkdata from parameter list.
   2209   Put a call to png_check_chunk_name() in png_read_chunk_header().
   2210   Revised png_check_chunk_name() to reject a name with a lowercase 3rd byte.
   2211   Removed two calls to png_check_chunk_name() occuring later in the process.
   2212 
   2213 version 1.0.38rc06, 1.2.30rc06 [July 29, 2008]
   2214   Added a call to png_check_chunk_name() in pngpread.c
   2215   Reverted png_check_chunk_name() to accept a name with a lowercase 3rd byte.
   2216 
   2217 version 1.0.38r07, 1.2.30r07 [August 2, 2008]
   2218   Changed "-Wall" to "-W -Wall" in the CFLAGS in all makefiles (Cosmin Truta)
   2219   Declared png_ptr "volatile" in pngread.c and pngwrite.c to avoid warnings.
   2220   Added code in pngset.c to quiet compiler warnings.
   2221   Updated contrib/visupng/cexcept.h to version 2.0.1
   2222   Relocated a misplaced "#endif /* PNG_NO_WRITE_FILTER */" in pngwutil.c
   2223 
   2224 version 1.0.38r08, 1.2.30r08 [August 2, 2008]
   2225   Enclose "volatile" declarations in #ifdef PNG_SETJMP_SUPPORTED (Cosmin).
   2226 
   2227 version 1.0.38, 1.2.30 [August 14, 2008]
   2228   No changes.
   2229 
   2230 version 1.2.31rc01 [August 19, 2008]
   2231   Removed extra crc check at the end of png_handle_cHRM().  Bug introduced
   2232     in libpng-1.2.30beta03 (Heiko Nitzsche).
   2233 
   2234 version 1.2.31rc02 [August 19, 2008]
   2235   Added PNG_WRITE_FLUSH_SUPPORTED block around new png_flush() call.
   2236 
   2237 version 1.2.31rc03 [August 19, 2008]
   2238   Added PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED block, off by default, around
   2239     new png_flush().
   2240 
   2241 version 1.0.39, 1.2.31 [August 21, 2008]
   2242   No changes.
   2243 
   2244 version 1.2.32beta01 [September 6, 2008]
   2245   Shortened tIME_string to 29 bytes in pngtest.c (bug introduced in
   2246     libpng-1.2.22).
   2247   Fixed off-by-one error introduced in png_push_read_zTXt() function in
   2248     libpng-1.2.30beta04/pngpread.c (Harald van Dijk)
   2249   These bugs have been given the vulnerability id CVE-2008-3964.
   2250 
   2251 version 1.0.40, 1.2.32 [September 18, 2008]
   2252   No changes.
   2253 
   2254 version 1.2.33beta01 [October 6, 2008]
   2255   Revised makefile.darwin to fix shared library numbering.
   2256   Change png_set_gray_1_2_4_to_8() to png_set_expand_gray_1_2_4_to_8()
   2257     in example.c (debian bug report)
   2258 
   2259 version 1.2.33rc01 [October 15, 2008]
   2260   No changes.
   2261 
   2262 version 1.0.41rc01, version 1.2.33rc02 [October 23, 2008]
   2263   Changed remaining "key" to "png_ptr->chunkdata" in png_handle_tEXt()
   2264     to avoid memory leak after memory failure while reading tEXt chunk.`
   2265 
   2266 version 1.2.33 [October 31, 2008]
   2267   No changes.
   2268 
   2269 version 1.2.34beta01 [November 27, 2008]
   2270   Revised png_warning() to write its message on standard output by default
   2271     when warning_fn is NULL. This was the behavior prior to libpng-1.2.9beta9.
   2272   Fixed string vs pointer-to-string error in png_check_keyword().
   2273   Added png_check_cHRM_fixed() in png.c and moved checking from pngget.c,
   2274     pngrutil.c, and pngwrite.c, and eliminated floating point cHRM checking.
   2275   Added check for zero-area RGB cHRM triangle in png_check_cHRM_fixed().
   2276   In png_check_cHRM_fixed(), ensure white_y is > 0, and removed redundant
   2277     check for all-zero coordinates that is detected by the triangle check.
   2278   Revised png_warning() to write its message on standard output by default
   2279     when warning_fn is NULL.
   2280 
   2281 version 1.2.34beta02 [November 28, 2008]
   2282   Corrected off-by-one error in bKGD validity check in png_write_bKGD()
   2283     and in png_handle_bKGD().
   2284 
   2285 version 1.2.34beta03 [December 1, 2008]
   2286   Revised bKGD validity check to use >= x instead of > x + 1
   2287   Merged with png_debug from libpng-1.4.0 to remove newlines.
   2288 
   2289 version 1.2.34beta04 [December 2, 2008]
   2290   More merging with png_debug from libpng-1.4.0 to remove newlines.
   2291 
   2292 version 1.2.34beta05 [December 5, 2008]
   2293   Removed redundant check for key==NULL before calling png_check_keyword()
   2294     to ensure that new_key gets initialized and removed extra warning
   2295     (Arvan Pritchard).
   2296 
   2297 version 1.2.34beta06 [December 9, 2008]
   2298   In png_write_png(), respect the placement of the filler bytes in an earlier
   2299     call to png_set_filler() (Jim Barry).
   2300 
   2301 version 1.2.34beta07 [December 9, 2008]
   2302   Undid previous change and added PNG_TRANSFORM_STRIP_FILLER_BEFORE and
   2303     PNG_TRANSFORM_STRIP_FILLER_AFTER conditionals and deprecated
   2304     PNG_TRANSFORM_STRIP_FILLER (Jim Barry).
   2305 
   2306 version 1.0.42rc01, 1.2.34rc01 [December 11, 2008]
   2307   No changes.
   2308 
   2309 version 1.0.42, 1.2.34 [December 18, 2008]
   2310   No changes.
   2311 
   2312 version 1.2.35beta01 [February 4, 2009]
   2313   Zero out some arrays of pointers after png_malloc(). (Tavis Ormandy)
   2314 
   2315 version 1.2.35beta02 [February 4, 2009]
   2316   Zero out more arrays of pointers after png_malloc().
   2317 
   2318 version 1.2.35beta03 [February 5, 2009]
   2319   Use png_memset() instead of a loop to intialize pointers.  We realize
   2320     this will not work on platforms where the NULL pointer is not all zeroes.
   2321 
   2322 version 1.2.35rc01 [February 11, 2009]
   2323   No changes.
   2324 
   2325 version 1.2.35rc02 [February 12, 2009]
   2326   Fix typo in new png_memset call in pngset.c (png_color should be png_charp)
   2327 
   2328 version 1.0.43 and 1.2.35 [February 14, 2009]
   2329   No changes.
   2330 
   2331 version 1.2.36beta01 [February 28, 2009]
   2332   Revised comments in png_set_read_fn() and png_set_write_fn().
   2333   Revised order of #ifdef's and indentation in png_debug definitions of png.h
   2334     bug introduced in libpng-1.2.34.
   2335 
   2336 version 1.2.36beta02 [March 21, 2009]
   2337   Use png_memset() after png_malloc() of big_row_buf when reading an
   2338     interlaced file, to avoid a possible UMR.
   2339   Undid recent revision of PNG_NO_STDIO version of png_write_flush().  Users
   2340     having trouble with fflush() can build with PNG_NO_WRITE_FLUSH defined.
   2341   Revised libpng*.txt documentation about use of png_write_flush().
   2342   Removed fflush() from pngtest.c.
   2343   Added "#define PNG_NO_WRITE_FLUSH" to contrib/pngminim/encoder/pngusr.h
   2344 
   2345 version 1.2.36beta03 [March 27, 2009]
   2346   Relocated misplaced PNG_1_0_X define in png.h that caused the prototype
   2347     for png_set_strip_error_numbers() to be omitted from PNG_NO_ASSEMBLER_CODE
   2348     builds.  This bug was introduced in libpng-1.2.15beta4.
   2349   Added a section on differences between 1.0.x and 1.2.x to libpng.3/libpng.txt
   2350 
   2351 version 1.2.36beta04 [April 5, 2009]
   2352   Fixed potential memory leak of "new_name" in png_write_iCCP() (Ralph Giles)
   2353 
   2354 version 1.2.36beta05 [April 24, 2009]
   2355   Added "ifndef PNG_SKIP_SETJMP_CHECK" block in pngconf.h to allow
   2356     application code writers to bypass the check for multiple inclusion
   2357     of setjmp.h when they know that it is safe to ignore the situation.
   2358   Made some cosmetic changes to whitespace in pngtest output.
   2359   Renamed "user_chunk_data" to "my_user_chunk_data" in pngtest.c to suppress
   2360     "shadowed declaration" warning from gcc-4.3.3.
   2361   Renamed "gamma" to "png_gamma" in pngset.c to avoid "shadowed declaration"
   2362     warning about a global "gamma" variable in math.h on some platforms.
   2363 
   2364 version 1.2.36rc01 [April 30, 2009]
   2365   No changes.
   2366 
   2367 version 1.0.44 and 1.2.36 [May 7, 2009]
   2368   No changes.
   2369 
   2370 version 1.2.37beta01 [May 14, 2009]
   2371   Fixed inconsistency in pngrutil.c, introduced in libpng-1.2.36.  The
   2372     memset() was using "png_ptr->rowbytes" instead of "row_bytes", which
   2373     the corresponding png_malloc() uses (Joe Drew).
   2374   Clarified usage of sig_bit versus sig_bit_p in example.c (Vincent Torri)
   2375   Updated some of the makefiles in the scripts directory (merged with
   2376     those in libpng-1.4.0beta57).
   2377 
   2378 version 1.2.37beta02 [May 19, 2009]
   2379   Fixed typo in libpng documentation (FILTER_AVE should be FILTER_AVG)
   2380   Relocated misplaced #endif in pngwrite.c, sCAL chunk handler.
   2381   Conditionally compile png_read_finish_row() which is not used by
   2382     progressive readers.
   2383   Added contrib/pngminim/preader to demonstrate building minimal progressive
   2384     decoder, based on contrib/gregbook with embedded libpng and zlib.
   2385 
   2386 version 1.2.37beta03 [May 20, 2009]
   2387   In contrib/pngminim/*, renamed "makefile.std" to "makefile", since there
   2388     is only one makefile in those directories, and revised the README files
   2389     accordingly.
   2390   Reformated sources in libpng style (3-space indentation, comment format)
   2391 
   2392 version 1.2.37rc01 [May 27, 2009]
   2393   No changes.
   2394 
   2395 versions 1.2.37 and 1.0.45 [June 4, 2009]
   2396   Reformatted several remaining "else statement;" and "if () statement;" into
   2397     two lines.
   2398   Added "#define PNG_NO_WRITE_SWAP" to contrib/pngminim/encoder/pngusr.h
   2399     and "define PNG_NO_READ_SWAP" to decoder/pngusr.h and preader/pngusr.h
   2400   Added sections about the git repository and our coding style to the
   2401     documentation (merged from libpng-1.4.0beta62)
   2402   Added a section to the libpng documentation about using png_get_io_ptr()
   2403     in configure scripts to detect the presence of libpng.
   2404 
   2405 version 1.2.38beta01 [June 17, 2009]
   2406   Revised libpng*.txt and libpng.3 to mention calling png_set_IHDR()
   2407     multiple times and to specify the sample order in the tRNS chunk,
   2408     because the ISO PNG specification has a typo in the tRNS table.
   2409   Changed several PNG_UNKNOWN_CHUNK_SUPPORTED to
   2410     PNG_HANDLE_AS_UNKNOWN_SUPPORTED, to make the png_set_keep mechanism
   2411     available for ignoring known chunks even when not saving unknown chunks.
   2412   Adopted preference for consistent use of "#ifdef" and "#ifndef" versus
   2413     "#if defined()" and "if !defined()" where possible.
   2414   Added PNG_NO_HANDLE_AS_UNKNOWN in the PNG_LEGACY_SUPPORTED block of
   2415     pngconf.h, and moved the various unknown chunk macro definitions
   2416     outside of the PNG_READ|WRITE_ANCILLARY_CHUNK_SUPPORTED blocks.
   2417 
   2418 version 1.0.46 [June 18, 2009]
   2419   Removed some editing cruft from scripts/libpng.pc.in and some makefiles.
   2420 
   2421 version 1.2.38rc01 [June 24, 2009]
   2422   No changes.
   2423 
   2424 version 1.2.38rc02 [June 29, 2009]
   2425   Added a reference to the libpng license in each source file.
   2426 
   2427 version 1.2.38rc03 [July 11, 2009]
   2428   Revised references to the libpng license in pngconf.h and contrib/visupng
   2429     source files.
   2430   Rebuilt configure scripts with autoconf-2.63.
   2431 
   2432 version 1.0.47 and 1.2.38 [July 16, 2009]
   2433   No changes.
   2434 
   2435 version 1.2.39beta01 [July 25, 2009]
   2436   Added a prototype for png_64bit_product() in png.c
   2437 
   2438 version 1.2.39beta02 [July 27, 2009]
   2439   Avoid a possible NULL dereference in debug build, in png_set_text_2().
   2440     (bug introduced in libpng-0.95, discovered by Evan Rouault)
   2441 
   2442 version 1.2.39beta03 [July 29, 2009]
   2443   Relocated new png_64_bit_product() prototype into png.h
   2444   Expanded the information about prototypes in the libpng style section of
   2445     the documentation.
   2446   Rebuilt configure scripts with autoconf-2.64.
   2447 
   2448 version 1.2.39beta04 [August 1, 2009]
   2449   Replaced *.tar.lzma with *.txz in distribution.  Get the xz codec
   2450     from <http://tukaani.org/xz>.
   2451 
   2452 version 1.2.39beta05 [August 1, 2009]
   2453   Reject attempt to write iCCP chunk with negative embedded profile length
   2454     (JD Chen)
   2455 
   2456 version 1.2.39c01 [August 6, 2009]
   2457   No changes.
   2458 
   2459 version 1.2.39 and 1.0.48 [August 13, 2009]
   2460   No changes.
   2461 
   2462 version 1.2.40beta01 [August 20, 2009]
   2463   Removed an extra png_debug() recently added to png_write_find_filter().
   2464   Fixed incorrect #ifdef in pngset.c regarding unknown chunk support.
   2465 
   2466 version 1.2.40rc01 [September 2, 2009]
   2467   Various bugfixes and improvements to CMakeLists.txt (Philip Lowman)
   2468 
   2469 version 1.2.40 and 1.0.49 [September 2, 2009]
   2470   No changes.
   2471 
   2472 version 1.0.50 [September 10, 2009]
   2473   Removed some editing cruft from pngset.c and pngwutil.c.
   2474 
   2475 version 1.2.41beta01 [September 25, 2009]
   2476   Moved redundant IHDR checking into new png_check_IHDR() in png.c
   2477     and report all errors found in the IHDR data.
   2478   Eliminated useless call to png_check_cHRM() from pngset.c
   2479   Expanded TAB characters in pngrtran.c
   2480 
   2481 version 1.2.41beta02 [September 30, 2009]
   2482   Revised png_check_IHDR().
   2483 
   2484 version 1.2.41beta03 [October 1, 2009]
   2485   Revised png_check_IHDR() again, to check info_ptr members instead of
   2486     the contents of the returned parameters.
   2487 
   2488 version 1.2.41beta04 [October 7, 2009]
   2489   Added "xcode" project similar one already in libpng-1.4.0beta (Alam Arias).
   2490   Ported some cosmetic changes from libpng-1.4.0beta86.
   2491   Eliminated a shadowed declaration of "pp" in png_handle_sPLT().
   2492 
   2493 version 1.2.41beta05 [October 17, 2009]
   2494   Revised pngconf.h to make it easier to enable iTXt support.  From libpng
   2495     version 1.2.9 through 1.2.40, defining PNG_iTXt_SUPPORTED did not work
   2496     as expected.
   2497   Ported some cosmetic changes from libpng-1.4.0beta87, changing
   2498     many "#if defined(x)" to "#ifdef x".
   2499 
   2500 version 1.2.41beta06 [October 18, 2009]
   2501   Restored PNG_USE_LOCAL_ARRAYS code in pngread.c that was inadvertently
   2502     deleted in libpng-1.2.41beta05.
   2503   Converted all PNG_NO_* tests to PNG_*_SUPPORTED everywhere except pngconf.h
   2504     as in libpng-1.4.0beta78 and later.
   2505 
   2506 version 1.2.41beta07 [October 21, 2009]
   2507   Ported some cosmetic changes from libpng-1.4.0rc01, changing
   2508     many "#if defined(x)" to "#ifdef x" in png.h and pngconf.h.
   2509 
   2510 version 1.2.41beta08 [October 30, 2009]
   2511   Ported from libpng-1.4.0rc01: png_calloc(), png_get_io_chunk_name(),
   2512     png_get_io_state(), png_set_user_cache_max(), png_get_user_cache_max(),
   2513     png_set_premultiply_alpha, and png_do_read_premultiply_alpha().
   2514   Relocated png_do_chop() ahead of building gamma tables in pngrtran.c
   2515     This avoids building 16-bit gamma tables unnecessarily.
   2516 
   2517 version 1.2.41beta09 [November 1, 2009]
   2518   Removed a harmless extra png_set_invert_alpha() from pngwrite.c
   2519   More bugfixes and improvements to CMakeLists.txt (Philip Lowman)
   2520   Moved CMakeLists.txt from scripts into the main libpng directory.
   2521   Apply png_user_chunk_cache_max within png_decompress_chunk().
   2522   Merged libpng-1.2.41.txt with libpng-1.4.0.txt where appropriate.
   2523 
   2524 version 1.2.41beta10 [November 1, 2009]
   2525   Enabled iTXt support by default. To ensure binary compatibility with
   2526     previous versions, the "lang" and "lang_key" members will be assumed
   2527     to be omitted from previous versions unless the current libpng
   2528     version was built with PNG_iTXt_SUPPORTED (which is otherwise no
   2529     longer necessary to gain iTXt support), as a signal that the user has
   2530     been building previous versions with PNG_iTXt_SUPPORTED as well.
   2531 
   2532 version 1.2.41beta11 [November 2, 2009]
   2533   Store user's user_png_ver in new png_ptr->user_png_ver element.
   2534   Revised iTXt support. To ensure binary compatibility with
   2535     previous versions, the "lang" and "lang_key" members will be assumed
   2536     to be omitted from versions prior to 1.2.41beta11 whenever there is a
   2537     library mismatch.
   2538 
   2539 version 1.2.41beta12 [November 2, 2009]
   2540   Free png_ptr->user_png_ver when destroying png_ptr.
   2541 
   2542 version 1.2.41beta13 [November 3, 2009]
   2543   Updated scripts/pngw32.def and projects/wince/png32ce.def
   2544   Copied projects/wince/png32ce.def to the scripts directory.
   2545   Added scripts/makefile.wce
   2546   Patched ltmain.sh for wince support.
   2547   Added PNG_CONVERT_tIME_SUPPORTED macro.
   2548 
   2549 version 1.2.41beta14 [November 8, 2009]
   2550   versions 1.2.41beta05 through 1.2.41beta13 were abandoned.
   2551   The 1.0.x/1.2.x series will only receive security updates from now on.
   2552   Make inclusion of time.h in pngconf.h depend on PNG_CONVERT_tIME_SUPPORTED
   2553   Make #define PNG_CONVERT_tIME_SUPPORTED depend on PNG_WRITE_tIME_SUPPORTED
   2554   Reverted iTXt compatibility stuff from 1.2.41beta05, 1.2.41beta11, and
   2555     1.2.41beta12.
   2556   Reverted IOSTATE feature, user_cache_max, and premultiply_alpha features
   2557     from 1.2.41beta08.
   2558   Retained png_calloc() from 1.2.41beta08 but as a non-exported function,
   2559     and removed reference to png_calloc from scripts/*.def
   2560 
   2561 version 1.2.41beta15 [November 8, 2009]
   2562   Added PNG_DEPSTRUCT, PNG_DEPRECATED, PNG_USE_RESULT, PNG_NORETURN, and
   2563     PNG_ALLOCATED macros to detect deprecated direct access to the
   2564     png_struct or info_struct members and other deprecated usage in
   2565     applications (John Bowler).
   2566   Updated scripts/makefile* to add "-DPNG_CONFIGURE_LIBPNG" to CFLAGS,
   2567     to prevent warnings about direct access to png structs by libpng
   2568     functions while building libpng.  They need to be tested, especially
   2569     those using compilers other than gcc.
   2570   Updated projects/visualc6 and visualc71 with "/d PNG_CONFIGURE_LIBPNG".
   2571 
   2572 version 1.2.41beta16 [November 9, 2009]
   2573   Removed three direct references to read_info_ptr members in pngtest.c
   2574     that were detected by the new PNG_DEPSTRUCT macro.
   2575   Only #define PNG_DEPSTRUCT, etc. in pngconf.h if not already defined.
   2576 
   2577 version 1.2.41beta17 [November 10, 2009]
   2578   Updated CMakeLists.txt to add "-DPNG_CONFIGURE_LIBPNG" to the definitions.
   2579   Marked deprecated function prototypes with PNG_DEPRECATED.
   2580   Marked memory allocation function prototypes with PNG_ALLOCATED.
   2581   Changed png_check_sig() to !png_sig_cmp() in contrib programs.
   2582   Corrected the png_get_IHDR() call in contrib/gregbook/readpng2.c
   2583   Added "-DPNG_CONFIGURE_LIBPNG" to the contrib/pngminum makefiles.
   2584 
   2585 version 1.2.41beta18 [November 11, 2009]
   2586   Renamed scripts/makefile.wce to scripts/makefile.cegcc
   2587   Marked nonexported functions with PNG_PRIVATE macro.
   2588 
   2589 version 1.2.41rc01 and 1.0.51rc01 [November 18, 2009]
   2590   Revised scripts/*.def to reflect functions actually exported by libpng.
   2591   Updated the copyright year in scripts/pngw32.rc from 2004 to 2009.
   2592   Moved descriptions of makefiles and other scripts out of INSTALL into
   2593     scripts/README.txt
   2594 
   2595 version 1.2.41rc02 [November 22, 2009]
   2596   Rebuilt the configure scripts with autoconf-2.65
   2597 
   2598 version 1.2.41rc03 [November 25, 2009]
   2599   Disabled the new pedantic warnings about deprecated function use
   2600     and deprecated structure access unless the user defines
   2601     PNG_PEDANTIC_WARNINGS.
   2602   Added "#define PNG_NO_PEDANTIC_WARNINGS" in the libpng source files.
   2603   Removed "-DPNG_CONFIGURE_LIBPNG" from the makefiles and projects.
   2604 
   2605 version 1.2.41 and 1.0.51 [December 3, 2009]
   2606   Updated the list of files and made some cosmetic changes in README.
   2607 
   2608 version 1.2.42beta01 [December 4, 2009]
   2609   Removed "#define PNG_NO_ERROR_NUMBERS" that was inadvertently added
   2610     to pngconf.h in version 1.2.41.
   2611   Revised scripts/makefile.netbsd, makefile.openbsd, and makefile.sco
   2612     to put png.h and pngconf.h in $prefix/include, like the other scripts,
   2613     instead of in $prefix/include/libpng.  Also revised makefile.sco
   2614     to put them in $prefix/include/libpng12 instead of in
   2615     $prefix/include/libpng/libpng12.
   2616   Removed leftover "-DPNG_CONFIGURE_LIBPNG" from scripts/makefile.darwin
   2617 
   2618 version 1.2.42beta02 [December 11, 2009]
   2619   Removed leftover "-DPNG_CONFIGURE_LIBPNG" from contrib/pngminim/*/makefile
   2620   Relocated png_do_chop() to its original position in pngrtran.c. The
   2621     change in version 1.2.41beta08 caused transparency to be handled wrong
   2622     in some 16-bit datastreams (Yusaku Sugai).
   2623 
   2624 version 1.2.42rc01 [December 17, 2009]
   2625   No changes.
   2626 
   2627 version 1.2.42rc02 [December 22, 2009]
   2628   Renamed libpng-pc.in back to libpng.pc.in and revised CMakeLists.txt
   2629     (revising changes made in 1.2.41beta17 and 1.2.41rc01)
   2630 
   2631 version 1.2.42rc03 [December 25, 2009]
   2632   Swapped PNG_UNKNOWN_CHUNKS_SUPPORTED and PNG_HANDLE_AS_UNKNOWN_SUPPORTED
   2633     in pngset.c to be consistent with other changes in version 1.2.38.
   2634 
   2635 version 1.2.42rc04 [January 1, 2010]
   2636   Marked png_memcpy_check() and png_memset_check() PNG_DEPRECATED.
   2637   Updated copyright year.
   2638 
   2639 version 1.2.42rc05 [January 2, 2010]
   2640   Avoid deprecated references to png_ptr-io_ptr and png_ptr->error_ptr
   2641     in pngtest.c
   2642 
   2643 version 1.2.42 and 1.0.52 [January 3, 2010]
   2644   No changes.
   2645 
   2646 version 1.2.43beta01 [January 27, 2010]
   2647   Updated CMakeLists.txt for consistent indentation and to avoid an
   2648     unclosed if-statement warning (Philip Lowman).
   2649   Removed "#ifdef PNG_1_0_X / #endif" surrounding
   2650     PNG_READ_16_TO_8_SUPPORTED and PNG_READ_GRAY_TO_RGB_SUPPORTED
   2651     in pngconf.h.  These were added in libpng-1.2.41beta08 and libpng-1.0.51,
   2652     which introduced a binary incompatibility with libpng-1.0.50.
   2653   Backported new png_decompress_chunk() algorithm from libpng-1.4.1.
   2654 
   2655 version 1.2.43beta02 [February 1, 2010]
   2656   Backported two-pass png_decompress_chunk() algorithm from libpng-1.4.1.
   2657 
   2658 version 1.2.43beta03 [February 6, 2010]
   2659   Backported fast png_push_save_buffer() algorithm from libpng-1.4.1.
   2660   Backported some cosmetic changes from libpng-1.4.1.
   2661 
   2662 version 1.2.43beta04 [February 8, 2010]
   2663   Reverted recent changes to png_push_save-buffer().
   2664   Removed PNGAPI declaration of png_calloc() and png_write_sig() in
   2665     1ibpng-1.2.X, introduced by mistake in libpng-1.2.41.
   2666   Return allocated "old_buffer" in png_push_save_buffer() before png_error()
   2667     to avoid a potential memory leak.
   2668 
   2669 version 1.2.43beta05 [February 8, 2010]
   2670   Ported rewritten png_decompress_chunk() by John Bowler from libpng-1.4.1.
   2671 
   2672 version 1.0.53rc01 and 1.2.43rc01 [February 18, 2010]
   2673   No changes.
   2674 
   2675 version 1.0.53rc02 and 1.2.43rc02 [February 19, 2010]
   2676   Define _ALL_SOURCE in configure.ac, makefile.aix, and CMakeLists.txt
   2677     when using AIX compiler.
   2678 
   2679 version 1.0.53 and 1.2.43 [February 25, 2010]
   2680   Removed unused gzio.c from contrib/pngminim gather and makefile scripts
   2681 
   2682 version 1.2.44beta01 [June 18, 2010]
   2683   In pngpread.c: png_push_have_row() add check for new_row > height
   2684   Removed the now-redundant check for out-of-bounds new_row from example.c
   2685 
   2686 version 1.2.44beta02 [June 19, 2010]
   2687   In pngpread.c: png_push_process_row() add check for too many rows.
   2688   Removed the now-redundant check for new_row > height in png_push_have_row().
   2689 
   2690 version 1.2.44beta03 [June 20, 2010]
   2691   Rewrote png_process_IDAT_data() to consistently treat extra data as warnings
   2692     and handle end conditions more cleanly.
   2693   Removed the new (beta02) check in png_push_process_row().
   2694 
   2695 version 1.2.44rc01 [June 21, 2010]
   2696   Revised some comments in png_process_IDAT_data().
   2697 
   2698 version 1.2.44rc02 [June 22, 2010]
   2699   Stop memory leak when reading a malformed sCAL chunk.
   2700 
   2701 version 1.2.44rc03 [June 23, 2010]
   2702   Revised pngpread.c patch of beta05 to avoid an endless loop.
   2703 
   2704 version 1.2.44 [June 26, 2010]
   2705   Updated some of the "last changed" dates.
   2706 
   2707 version 1.2.45beta01 [June 7, 2011]
   2708   Fixed uninitialized memory read in png_format_buffer() (Bug
   2709     report by Frank Busse, related to CVE-2004-0421).
   2710   Pass "" instead of '\0' to png_default_error() in png_err().  This mistake
   2711     was introduced in libpng-1.2.20beta01.
   2712   Check for up->location !PNG_AFTER_IDAT when writing unknown chunks
   2713     before IDAT.
   2714   Ported bugfix in pngrtran.c from 1.5.3: when expanding a paletted image,
   2715     always expand to RGBA if transparency is present.
   2716 
   2717 version 1.2.45beta02 [June 8, 2011]
   2718   Check for integer overflow in png_set_rgb_to_gray().
   2719 
   2720 version 1.2.45beta03 [June 19, 2011]
   2721   Check for sCAL chunk too short.
   2722 
   2723 version 1.2.45rc01 and 1.0.55rc01 [June 30, 2011]
   2724   Updated "last changed" dates and copyright year.
   2725 
   2726 version 1.2.45 and 1.0.55 [July 7, 2011]
   2727   No changes.
   2728 
   2729 version 1.2.46rc01 and 1.0.56rc01 [July 8, 2011]
   2730   Reverted changes to Makefile.am and Makefile.in to libpng-1.2.44 versions.
   2731 
   2732 version 1.2.46rc02 and 1.0.56rc02 [July 8, 2011]
   2733   Added CMakeLists.txt, projects/xcode, and pnggccrd.c to EXTRA_DIST in
   2734     Makefile.am and Makefile.in
   2735 
   2736 version 1.2.46 and 1.0.56 [July 9, 2011]
   2737   Udated copyright year to 2011.
   2738 
   2739 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
   2740 (subscription required; visit
   2741 https://lists.sourceforge.net/lists/listinfo/png-mng-implement
   2742 to subscribe)
   2743 or to glennrp at users.sourceforge.net
   2744 
   2745 Glenn R-P
   2746 */
   2747