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      1 
      2 /* png.h - header file for PNG reference library
      3  *
      4  * libpng version 1.2.19 - August 18, 2007
      5  * Copyright (c) 1998-2007 Glenn Randers-Pehrson
      6  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
      7  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
      8  *
      9  * Authors and maintainers:
     10  *  libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
     11  *  libpng versions 0.89c, June 1996, through 0.96, May 1997: Andreas Dilger
     12  *  libpng versions 0.97, January 1998, through 1.2.19 - August 18, 2007: Glenn
     13  *  See also "Contributing Authors", below.
     14  *
     15  * Note about libpng version numbers:
     16  *
     17  *    Due to various miscommunications, unforeseen code incompatibilities
     18  *    and occasional factors outside the authors' control, version numbering
     19  *    on the library has not always been consistent and straightforward.
     20  *    The following table summarizes matters since version 0.89c, which was
     21  *    the first widely used release:
     22  *
     23  *    source                 png.h  png.h  shared-lib
     24  *    version                string   int  version
     25  *    -------                ------ -----  ----------
     26  *    0.89c "1.0 beta 3"     0.89      89  1.0.89
     27  *    0.90  "1.0 beta 4"     0.90      90  0.90  [should have been 2.0.90]
     28  *    0.95  "1.0 beta 5"     0.95      95  0.95  [should have been 2.0.95]
     29  *    0.96  "1.0 beta 6"     0.96      96  0.96  [should have been 2.0.96]
     30  *    0.97b "1.00.97 beta 7" 1.00.97   97  1.0.1 [should have been 2.0.97]
     31  *    0.97c                  0.97      97  2.0.97
     32  *    0.98                   0.98      98  2.0.98
     33  *    0.99                   0.99      98  2.0.99
     34  *    0.99a-m                0.99      99  2.0.99
     35  *    1.00                   1.00     100  2.1.0 [100 should be 10000]
     36  *    1.0.0      (from here on, the   100  2.1.0 [100 should be 10000]
     37  *    1.0.1       png.h string is   10001  2.1.0
     38  *    1.0.1a-e    identical to the  10002  from here on, the shared library
     39  *    1.0.2       source version)   10002  is 2.V where V is the source code
     40  *    1.0.2a-b                      10003  version, except as noted.
     41  *    1.0.3                         10003
     42  *    1.0.3a-d                      10004
     43  *    1.0.4                         10004
     44  *    1.0.4a-f                      10005
     45  *    1.0.5 (+ 2 patches)           10005
     46  *    1.0.5a-d                      10006
     47  *    1.0.5e-r                      10100 (not source compatible)
     48  *    1.0.5s-v                      10006 (not binary compatible)
     49  *    1.0.6 (+ 3 patches)           10006 (still binary incompatible)
     50  *    1.0.6d-f                      10007 (still binary incompatible)
     51  *    1.0.6g                        10007
     52  *    1.0.6h                        10007  10.6h (testing xy.z so-numbering)
     53  *    1.0.6i                        10007  10.6i
     54  *    1.0.6j                        10007  2.1.0.6j (incompatible with 1.0.0)
     55  *    1.0.7beta11-14        DLLNUM  10007  2.1.0.7beta11-14 (binary compatible)
     56  *    1.0.7beta15-18           1    10007  2.1.0.7beta15-18 (binary compatible)
     57  *    1.0.7rc1-2               1    10007  2.1.0.7rc1-2 (binary compatible)
     58  *    1.0.7                    1    10007  (still compatible)
     59  *    1.0.8beta1-4             1    10008  2.1.0.8beta1-4
     60  *    1.0.8rc1                 1    10008  2.1.0.8rc1
     61  *    1.0.8                    1    10008  2.1.0.8
     62  *    1.0.9beta1-6             1    10009  2.1.0.9beta1-6
     63  *    1.0.9rc1                 1    10009  2.1.0.9rc1
     64  *    1.0.9beta7-10            1    10009  2.1.0.9beta7-10
     65  *    1.0.9rc2                 1    10009  2.1.0.9rc2
     66  *    1.0.9                    1    10009  2.1.0.9
     67  *    1.0.10beta1              1    10010  2.1.0.10beta1
     68  *    1.0.10rc1                1    10010  2.1.0.10rc1
     69  *    1.0.10                   1    10010  2.1.0.10
     70  *    1.0.11beta1-3            1    10011  2.1.0.11beta1-3
     71  *    1.0.11rc1                1    10011  2.1.0.11rc1
     72  *    1.0.11                   1    10011  2.1.0.11
     73  *    1.0.12beta1-2            2    10012  2.1.0.12beta1-2
     74  *    1.0.12rc1                2    10012  2.1.0.12rc1
     75  *    1.0.12                   2    10012  2.1.0.12
     76  *    1.1.0a-f                 -    10100  2.1.1.0a-f (branch abandoned)
     77  *    1.2.0beta1-2             2    10200  2.1.2.0beta1-2
     78  *    1.2.0beta3-5             3    10200  3.1.2.0beta3-5
     79  *    1.2.0rc1                 3    10200  3.1.2.0rc1
     80  *    1.2.0                    3    10200  3.1.2.0
     81  *    1.2.1beta1-4             3    10201  3.1.2.1beta1-4
     82  *    1.2.1rc1-2               3    10201  3.1.2.1rc1-2
     83  *    1.2.1                    3    10201  3.1.2.1
     84  *    1.2.2beta1-6            12    10202  12.so.0.1.2.2beta1-6
     85  *    1.0.13beta1             10    10013  10.so.0.1.0.13beta1
     86  *    1.0.13rc1               10    10013  10.so.0.1.0.13rc1
     87  *    1.2.2rc1                12    10202  12.so.0.1.2.2rc1
     88  *    1.0.13                  10    10013  10.so.0.1.0.13
     89  *    1.2.2                   12    10202  12.so.0.1.2.2
     90  *    1.2.3rc1-6              12    10203  12.so.0.1.2.3rc1-6
     91  *    1.2.3                   12    10203  12.so.0.1.2.3
     92  *    1.2.4beta1-3            13    10204  12.so.0.1.2.4beta1-3
     93  *    1.0.14rc1               13    10014  10.so.0.1.0.14rc1
     94  *    1.2.4rc1                13    10204  12.so.0.1.2.4rc1
     95  *    1.0.14                  10    10014  10.so.0.1.0.14
     96  *    1.2.4                   13    10204  12.so.0.1.2.4
     97  *    1.2.5beta1-2            13    10205  12.so.0.1.2.5beta1-2
     98  *    1.0.15rc1-3             10    10015  10.so.0.1.0.15rc1-3
     99  *    1.2.5rc1-3              13    10205  12.so.0.1.2.5rc1-3
    100  *    1.0.15                  10    10015  10.so.0.1.0.15
    101  *    1.2.5                   13    10205  12.so.0.1.2.5
    102  *    1.2.6beta1-4            13    10206  12.so.0.1.2.6beta1-4
    103  *    1.0.16                  10    10016  10.so.0.1.0.16
    104  *    1.2.6                   13    10206  12.so.0.1.2.6
    105  *    1.2.7beta1-2            13    10207  12.so.0.1.2.7beta1-2
    106  *    1.0.17rc1               10    10017  10.so.0.1.0.17rc1
    107  *    1.2.7rc1                13    10207  12.so.0.1.2.7rc1
    108  *    1.0.17                  10    10017  10.so.0.1.0.17
    109  *    1.2.7                   13    10207  12.so.0.1.2.7
    110  *    1.2.8beta1-5            13    10208  12.so.0.1.2.8beta1-5
    111  *    1.0.18rc1-5             10    10018  10.so.0.1.0.18rc1-5
    112  *    1.2.8rc1-5              13    10208  12.so.0.1.2.8rc1-5
    113  *    1.0.18                  10    10018  10.so.0.1.0.18
    114  *    1.2.8                   13    10208  12.so.0.1.2.8
    115  *    1.2.9beta1-3            13    10209  12.so.0.1.2.9beta1-3
    116  *    1.2.9beta4-11           13    10209  12.so.0.9[.0]
    117  *    1.2.9rc1                13    10209  12.so.0.9[.0]
    118  *    1.2.9                   13    10209  12.so.0.9[.0]
    119  *    1.2.10beta1-8           13    10210  12.so.0.10[.0]
    120  *    1.2.10rc1-3             13    10210  12.so.0.10[.0]
    121  *    1.2.10                  13    10210  12.so.0.10[.0]
    122  *    1.2.11beta1-4           13    10211  12.so.0.11[.0]
    123  *    1.0.19rc1-5             10    10019  10.so.0.19[.0]
    124  *    1.2.11rc1-5             13    10211  12.so.0.11[.0]
    125  *    1.0.19                  10    10019  10.so.0.19[.0]
    126  *    1.2.11                  13    10211  12.so.0.11[.0]
    127  *    1.0.20                  10    10020  10.so.0.20[.0]
    128  *    1.2.12                  13    10212  12.so.0.12[.0]
    129  *    1.2.13beta1             13    10213  12.so.0.13[.0]
    130  *    1.0.21                  10    10021  10.so.0.21[.0]
    131  *    1.2.13                  13    10213  12.so.0.13[.0]
    132  *    1.2.14beta1-2           13    10214  12.so.0.14[.0]
    133  *    1.0.22rc1               10    10022  10.so.0.22[.0]
    134  *    1.2.14rc1               13    10214  12.so.0.14[.0]
    135  *    1.0.22                  10    10022  10.so.0.22[.0]
    136  *    1.2.14                  13    10214  12.so.0.14[.0]
    137  *    1.2.15beta1-6           13    10215  12.so.0.15[.0]
    138  *    1.0.23rc1-5             10    10023  10.so.0.23[.0]
    139  *    1.2.15rc1-5             13    10215  12.so.0.15[.0]
    140  *    1.0.23                  10    10023  10.so.0.23[.0]
    141  *    1.2.15                  13    10215  12.so.0.15[.0]
    142  *    1.2.16beta1-2           13    10216  12.so.0.16[.0]
    143  *    1.2.16rc1               13    10216  12.so.0.16[.0]
    144  *    1.0.24                  10    10024  10.so.0.24[.0]
    145  *    1.2.16                  13    10216  12.so.0.16[.0]
    146  *    1.2.17beta1-2           13    10217  12.so.0.17[.0]
    147  *    1.0.25rc1               10    10025  10.so.0.25[.0]
    148  *    1.2.17rc1-3             13    10217  12.so.0.17[.0]
    149  *    1.0.25                  10    10025  10.so.0.25[.0]
    150  *    1.2.17                  13    10217  12.so.0.17[.0]
    151  *    1.0.26                  10    10026  10.so.0.26[.0]
    152  *    1.2.18                  13    10218  12.so.0.18[.0]
    153  *    1.2.19beta1-31          13    10219  12.so.0.19[.0]
    154  *    1.0.27rc1-6             10    10027  10.so.0.27[.0]
    155  *    1.2.19rc1-6             13    10219  12.so.0.19[.0]
    156  *    1.0.27                  10    10027  10.so.0.27[.0]
    157  *    1.2.19                  13    10219  12.so.0.19[.0]
    158  *
    159  *    Henceforth the source version will match the shared-library major
    160  *    and minor numbers; the shared-library major version number will be
    161  *    used for changes in backward compatibility, as it is intended.  The
    162  *    PNG_LIBPNG_VER macro, which is not used within libpng but is available
    163  *    for applications, is an unsigned integer of the form xyyzz corresponding
    164  *    to the source version x.y.z (leading zeros in y and z).  Beta versions
    165  *    were given the previous public release number plus a letter, until
    166  *    version 1.0.6j; from then on they were given the upcoming public
    167  *    release number plus "betaNN" or "rcN".
    168  *
    169  *    Binary incompatibility exists only when applications make direct access
    170  *    to the info_ptr or png_ptr members through png.h, and the compiled
    171  *    application is loaded with a different version of the library.
    172  *
    173  *    DLLNUM will change each time there are forward or backward changes
    174  *    in binary compatibility (e.g., when a new feature is added).
    175  *
    176  * See libpng.txt or libpng.3 for more information.  The PNG specification
    177  * is available as a W3C Recommendation and as an ISO Specification,
    178  * <http://www.w3.org/TR/2003/REC-PNG-20031110/
    179  */
    180 
    181 /*
    182  * COPYRIGHT NOTICE, DISCLAIMER, and LICENSE:
    183  *
    184  * If you modify libpng you may insert additional notices immediately following
    185  * this sentence.
    186  *
    187  * libpng versions 1.2.6, August 15, 2004, through 1.2.19, August 18, 2007, are
    188  * Copyright (c) 2004, 2006-2007 Glenn Randers-Pehrson, and are
    189  * distributed according to the same disclaimer and license as libpng-1.2.5
    190  * with the following individual added to the list of Contributing Authors:
    191  *
    192  *    Cosmin Truta
    193  *
    194  * libpng versions 1.0.7, July 1, 2000, through 1.2.5, October 3, 2002, are
    195  * Copyright (c) 2000-2002 Glenn Randers-Pehrson, and are
    196  * distributed according to the same disclaimer and license as libpng-1.0.6
    197  * with the following individuals added to the list of Contributing Authors:
    198  *
    199  *    Simon-Pierre Cadieux
    200  *    Eric S. Raymond
    201  *    Gilles Vollant
    202  *
    203  * and with the following additions to the disclaimer:
    204  *
    205  *    There is no warranty against interference with your enjoyment of the
    206  *    library or against infringement.  There is no warranty that our
    207  *    efforts or the library will fulfill any of your particular purposes
    208  *    or needs.  This library is provided with all faults, and the entire
    209  *    risk of satisfactory quality, performance, accuracy, and effort is with
    210  *    the user.
    211  *
    212  * libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
    213  * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson, and are
    214  * distributed according to the same disclaimer and license as libpng-0.96,
    215  * with the following individuals added to the list of Contributing Authors:
    216  *
    217  *    Tom Lane
    218  *    Glenn Randers-Pehrson
    219  *    Willem van Schaik
    220  *
    221  * libpng versions 0.89, June 1996, through 0.96, May 1997, are
    222  * Copyright (c) 1996, 1997 Andreas Dilger
    223  * Distributed according to the same disclaimer and license as libpng-0.88,
    224  * with the following individuals added to the list of Contributing Authors:
    225  *
    226  *    John Bowler
    227  *    Kevin Bracey
    228  *    Sam Bushell
    229  *    Magnus Holmgren
    230  *    Greg Roelofs
    231  *    Tom Tanner
    232  *
    233  * libpng versions 0.5, May 1995, through 0.88, January 1996, are
    234  * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
    235  *
    236  * For the purposes of this copyright and license, "Contributing Authors"
    237  * is defined as the following set of individuals:
    238  *
    239  *    Andreas Dilger
    240  *    Dave Martindale
    241  *    Guy Eric Schalnat
    242  *    Paul Schmidt
    243  *    Tim Wegner
    244  *
    245  * The PNG Reference Library is supplied "AS IS".  The Contributing Authors
    246  * and Group 42, Inc. disclaim all warranties, expressed or implied,
    247  * including, without limitation, the warranties of merchantability and of
    248  * fitness for any purpose.  The Contributing Authors and Group 42, Inc.
    249  * assume no liability for direct, indirect, incidental, special, exemplary,
    250  * or consequential damages, which may result from the use of the PNG
    251  * Reference Library, even if advised of the possibility of such damage.
    252  *
    253  * Permission is hereby granted to use, copy, modify, and distribute this
    254  * source code, or portions hereof, for any purpose, without fee, subject
    255  * to the following restrictions:
    256  *
    257  * 1. The origin of this source code must not be misrepresented.
    258  *
    259  * 2. Altered versions must be plainly marked as such and
    260  * must not be misrepresented as being the original source.
    261  *
    262  * 3. This Copyright notice may not be removed or altered from
    263  *    any source or altered source distribution.
    264  *
    265  * The Contributing Authors and Group 42, Inc. specifically permit, without
    266  * fee, and encourage the use of this source code as a component to
    267  * supporting the PNG file format in commercial products.  If you use this
    268  * source code in a product, acknowledgment is not required but would be
    269  * appreciated.
    270  */
    271 
    272 /*
    273  * A "png_get_copyright" function is available, for convenient use in "about"
    274  * boxes and the like:
    275  *
    276  * printf("%s",png_get_copyright(NULL));
    277  *
    278  * Also, the PNG logo (in PNG format, of course) is supplied in the
    279  * files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).
    280  */
    281 
    282 /*
    283  * Libpng is OSI Certified Open Source Software.  OSI Certified is a
    284  * certification mark of the Open Source Initiative.
    285  */
    286 
    287 /*
    288  * The contributing authors would like to thank all those who helped
    289  * with testing, bug fixes, and patience.  This wouldn't have been
    290  * possible without all of you.
    291  *
    292  * Thanks to Frank J. T. Wojcik for helping with the documentation.
    293  */
    294 
    295 /*
    296  * Y2K compliance in libpng:
    297  * =========================
    298  *
    299  *    August 18, 2007
    300  *
    301  *    Since the PNG Development group is an ad-hoc body, we can't make
    302  *    an official declaration.
    303  *
    304  *    This is your unofficial assurance that libpng from version 0.71 and
    305  *    upward through 1.2.19 are Y2K compliant.  It is my belief that earlier
    306  *    versions were also Y2K compliant.
    307  *
    308  *    Libpng only has three year fields.  One is a 2-byte unsigned integer
    309  *    that will hold years up to 65535.  The other two hold the date in text
    310  *    format, and will hold years up to 9999.
    311  *
    312  *    The integer is
    313  *        "png_uint_16 year" in png_time_struct.
    314  *
    315  *    The strings are
    316  *        "png_charp time_buffer" in png_struct and
    317  *        "near_time_buffer", which is a local character string in png.c.
    318  *
    319  *    There are seven time-related functions:
    320  *        png.c: png_convert_to_rfc_1123() in png.c
    321  *          (formerly png_convert_to_rfc_1152() in error)
    322  *        png_convert_from_struct_tm() in pngwrite.c, called in pngwrite.c
    323  *        png_convert_from_time_t() in pngwrite.c
    324  *        png_get_tIME() in pngget.c
    325  *        png_handle_tIME() in pngrutil.c, called in pngread.c
    326  *        png_set_tIME() in pngset.c
    327  *        png_write_tIME() in pngwutil.c, called in pngwrite.c
    328  *
    329  *    All handle dates properly in a Y2K environment.  The
    330  *    png_convert_from_time_t() function calls gmtime() to convert from system
    331  *    clock time, which returns (year - 1900), which we properly convert to
    332  *    the full 4-digit year.  There is a possibility that applications using
    333  *    libpng are not passing 4-digit years into the png_convert_to_rfc_1123()
    334  *    function, or that they are incorrectly passing only a 2-digit year
    335  *    instead of "year - 1900" into the png_convert_from_struct_tm() function,
    336  *    but this is not under our control.  The libpng documentation has always
    337  *    stated that it works with 4-digit years, and the APIs have been
    338  *    documented as such.
    339  *
    340  *    The tIME chunk itself is also Y2K compliant.  It uses a 2-byte unsigned
    341  *    integer to hold the year, and can hold years as large as 65535.
    342  *
    343  *    zlib, upon which libpng depends, is also Y2K compliant.  It contains
    344  *    no date-related code.
    345  *
    346  *       Glenn Randers-Pehrson
    347  *       libpng maintainer
    348  *       PNG Development Group
    349  */
    350 
    351 #ifndef PNG_H
    352 #define PNG_H
    353 
    354 /* This is not the place to learn how to use libpng.  The file libpng.txt
    355  * describes how to use libpng, and the file example.c summarizes it
    356  * with some code on which to build.  This file is useful for looking
    357  * at the actual function definitions and structure components.
    358  */
    359 
    360 /* Version information for png.h - this should match the version in png.c */
    361 #define PNG_LIBPNG_VER_STRING "1.2.19"
    362 #define PNG_HEADER_VERSION_STRING \
    363    " libpng version 1.2.19 - August 18, 2007\n"
    364 
    365 #define PNG_LIBPNG_VER_SONUM   0
    366 #define PNG_LIBPNG_VER_DLLNUM  13
    367 
    368 /* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
    369 #define PNG_LIBPNG_VER_MAJOR   1
    370 #define PNG_LIBPNG_VER_MINOR   2
    371 #define PNG_LIBPNG_VER_RELEASE 19
    372 /* This should match the numeric part of the final component of
    373  * PNG_LIBPNG_VER_STRING, omitting any leading zero: */
    374 
    375 #define PNG_LIBPNG_VER_BUILD  0
    376 
    377 /* Release Status */
    378 #define PNG_LIBPNG_BUILD_ALPHA    1
    379 #define PNG_LIBPNG_BUILD_BETA     2
    380 #define PNG_LIBPNG_BUILD_RC       3
    381 #define PNG_LIBPNG_BUILD_STABLE   4
    382 #define PNG_LIBPNG_BUILD_RELEASE_STATUS_MASK 7
    383 
    384 /* Release-Specific Flags */
    385 #define PNG_LIBPNG_BUILD_PATCH    8 /* Can be OR'ed with
    386                                        PNG_LIBPNG_BUILD_STABLE only */
    387 #define PNG_LIBPNG_BUILD_PRIVATE 16 /* Cannot be OR'ed with
    388                                        PNG_LIBPNG_BUILD_SPECIAL */
    389 #define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
    390                                        PNG_LIBPNG_BUILD_PRIVATE */
    391 
    392 #define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_STABLE
    393 
    394 /* Careful here.  At one time, Guy wanted to use 082, but that would be octal.
    395  * We must not include leading zeros.
    396  * Versions 0.7 through 1.0.0 were in the range 0 to 100 here (only
    397  * version 1.0.0 was mis-numbered 100 instead of 10000).  From
    398  * version 1.0.1 it's    xxyyzz, where x=major, y=minor, z=release */
    399 #define PNG_LIBPNG_VER 10219 /* 1.2.19 */
    400 
    401 #ifndef PNG_VERSION_INFO_ONLY
    402 /* include the compression library's header */
    403 #include "zlib.h"
    404 #endif
    405 
    406 /* include all user configurable info, including optional assembler routines */
    407 #include "pngconf.h"
    408 
    409 /*
    410  * Added at libpng-1.2.8 */
    411 /* Ref MSDN: Private as priority over Special
    412  * VS_FF_PRIVATEBUILD File *was not* built using standard release
    413  * procedures. If this value is given, the StringFileInfo block must
    414  * contain a PrivateBuild string.
    415  *
    416  * VS_FF_SPECIALBUILD File *was* built by the original company using
    417  * standard release procedures but is a variation of the standard
    418  * file of the same version number. If this value is given, the
    419  * StringFileInfo block must contain a SpecialBuild string.
    420  */
    421 
    422 #if defined(PNG_USER_PRIVATEBUILD)
    423 #  define PNG_LIBPNG_BUILD_TYPE \
    424           (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_PRIVATE)
    425 #else
    426 #  if defined(PNG_LIBPNG_SPECIALBUILD)
    427 #    define PNG_LIBPNG_BUILD_TYPE \
    428             (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_SPECIAL)
    429 #  else
    430 #    define PNG_LIBPNG_BUILD_TYPE (PNG_LIBPNG_BUILD_BASE_TYPE)
    431 #  endif
    432 #endif
    433 
    434 #ifndef PNG_VERSION_INFO_ONLY
    435 
    436 /* Inhibit C++ name-mangling for libpng functions but not for system calls. */
    437 #ifdef __cplusplus
    438 extern "C" {
    439 #endif /* __cplusplus */
    440 
    441 /* This file is arranged in several sections.  The first section contains
    442  * structure and type definitions.  The second section contains the external
    443  * library functions, while the third has the internal library functions,
    444  * which applications aren't expected to use directly.
    445  */
    446 
    447 #ifndef PNG_NO_TYPECAST_NULL
    448 #define int_p_NULL                (int *)NULL
    449 #define png_bytep_NULL            (png_bytep)NULL
    450 #define png_bytepp_NULL           (png_bytepp)NULL
    451 #define png_doublep_NULL          (png_doublep)NULL
    452 #define png_error_ptr_NULL        (png_error_ptr)NULL
    453 #define png_flush_ptr_NULL        (png_flush_ptr)NULL
    454 #define png_free_ptr_NULL         (png_free_ptr)NULL
    455 #define png_infopp_NULL           (png_infopp)NULL
    456 #define png_malloc_ptr_NULL       (png_malloc_ptr)NULL
    457 #define png_read_status_ptr_NULL  (png_read_status_ptr)NULL
    458 #define png_rw_ptr_NULL           (png_rw_ptr)NULL
    459 #define png_structp_NULL          (png_structp)NULL
    460 #define png_uint_16p_NULL         (png_uint_16p)NULL
    461 #define png_voidp_NULL            (png_voidp)NULL
    462 #define png_write_status_ptr_NULL (png_write_status_ptr)NULL
    463 #else
    464 #define int_p_NULL                NULL
    465 #define png_bytep_NULL            NULL
    466 #define png_bytepp_NULL           NULL
    467 #define png_doublep_NULL          NULL
    468 #define png_error_ptr_NULL        NULL
    469 #define png_flush_ptr_NULL        NULL
    470 #define png_free_ptr_NULL         NULL
    471 #define png_infopp_NULL           NULL
    472 #define png_malloc_ptr_NULL       NULL
    473 #define png_read_status_ptr_NULL  NULL
    474 #define png_rw_ptr_NULL           NULL
    475 #define png_structp_NULL          NULL
    476 #define png_uint_16p_NULL         NULL
    477 #define png_voidp_NULL            NULL
    478 #define png_write_status_ptr_NULL NULL
    479 #endif
    480 
    481 /* variables declared in png.c - only it needs to define PNG_NO_EXTERN */
    482 #if !defined(PNG_NO_EXTERN) || defined(PNG_ALWAYS_EXTERN)
    483 /* Version information for C files, stored in png.c.  This had better match
    484  * the version above.
    485  */
    486 #ifdef PNG_USE_GLOBAL_ARRAYS
    487 PNG_EXPORT_VAR (PNG_CONST char) png_libpng_ver[18];
    488   /* need room for 99.99.99beta99z */
    489 #else
    490 #define png_libpng_ver png_get_header_ver(NULL)
    491 #endif
    492 
    493 #ifdef PNG_USE_GLOBAL_ARRAYS
    494 /* This was removed in version 1.0.5c */
    495 /* Structures to facilitate easy interlacing.  See png.c for more details */
    496 PNG_EXPORT_VAR (PNG_CONST int FARDATA) png_pass_start[7];
    497 PNG_EXPORT_VAR (PNG_CONST int FARDATA) png_pass_inc[7];
    498 PNG_EXPORT_VAR (PNG_CONST int FARDATA) png_pass_ystart[7];
    499 PNG_EXPORT_VAR (PNG_CONST int FARDATA) png_pass_yinc[7];
    500 PNG_EXPORT_VAR (PNG_CONST int FARDATA) png_pass_mask[7];
    501 PNG_EXPORT_VAR (PNG_CONST int FARDATA) png_pass_dsp_mask[7];
    502 #if defined(PNG_HAVE_MMX_COMBINE_ROW) || defined(PNG_OPTIMIZED_CODE_SUPPORTED)
    503 PNG_EXPORT_VAR (PNG_CONST int FARDATA) png_pass_width[7];
    504 #endif
    505 /* This isn't currently used.  If you need it, see png.c for more details.
    506 PNG_EXPORT_VAR (PNG_CONST int FARDATA) png_pass_height[7];
    507 */
    508 #endif
    509 
    510 #endif /* PNG_NO_EXTERN */
    511 
    512 /* Three color definitions.  The order of the red, green, and blue, (and the
    513  * exact size) is not important, although the size of the fields need to
    514  * be png_byte or png_uint_16 (as defined below).
    515  */
    516 typedef struct png_color_struct
    517 {
    518    png_byte red;
    519    png_byte green;
    520    png_byte blue;
    521 } png_color;
    522 typedef png_color FAR * png_colorp;
    523 typedef png_color FAR * FAR * png_colorpp;
    524 
    525 typedef struct png_color_16_struct
    526 {
    527    png_byte index;    /* used for palette files */
    528    png_uint_16 red;   /* for use in red green blue files */
    529    png_uint_16 green;
    530    png_uint_16 blue;
    531    png_uint_16 gray;  /* for use in grayscale files */
    532 } png_color_16;
    533 typedef png_color_16 FAR * png_color_16p;
    534 typedef png_color_16 FAR * FAR * png_color_16pp;
    535 
    536 typedef struct png_color_8_struct
    537 {
    538    png_byte red;   /* for use in red green blue files */
    539    png_byte green;
    540    png_byte blue;
    541    png_byte gray;  /* for use in grayscale files */
    542    png_byte alpha; /* for alpha channel files */
    543 } png_color_8;
    544 typedef png_color_8 FAR * png_color_8p;
    545 typedef png_color_8 FAR * FAR * png_color_8pp;
    546 
    547 /*
    548  * The following two structures are used for the in-core representation
    549  * of sPLT chunks.
    550  */
    551 typedef struct png_sPLT_entry_struct
    552 {
    553    png_uint_16 red;
    554    png_uint_16 green;
    555    png_uint_16 blue;
    556    png_uint_16 alpha;
    557    png_uint_16 frequency;
    558 } png_sPLT_entry;
    559 typedef png_sPLT_entry FAR * png_sPLT_entryp;
    560 typedef png_sPLT_entry FAR * FAR * png_sPLT_entrypp;
    561 
    562 /*  When the depth of the sPLT palette is 8 bits, the color and alpha samples
    563  *  occupy the LSB of their respective members, and the MSB of each member
    564  *  is zero-filled.  The frequency member always occupies the full 16 bits.
    565  */
    566 
    567 typedef struct png_sPLT_struct
    568 {
    569    png_charp name;           /* palette name */
    570    png_byte depth;           /* depth of palette samples */
    571    png_sPLT_entryp entries;  /* palette entries */
    572    png_int_32 nentries;      /* number of palette entries */
    573 } png_sPLT_t;
    574 typedef png_sPLT_t FAR * png_sPLT_tp;
    575 typedef png_sPLT_t FAR * FAR * png_sPLT_tpp;
    576 
    577 #ifdef PNG_TEXT_SUPPORTED
    578 /* png_text holds the contents of a text/ztxt/itxt chunk in a PNG file,
    579  * and whether that contents is compressed or not.  The "key" field
    580  * points to a regular zero-terminated C string.  The "text", "lang", and
    581  * "lang_key" fields can be regular C strings, empty strings, or NULL pointers.
    582  * However, the * structure returned by png_get_text() will always contain
    583  * regular zero-terminated C strings (possibly empty), never NULL pointers,
    584  * so they can be safely used in printf() and other string-handling functions.
    585  */
    586 typedef struct png_text_struct
    587 {
    588    int  compression;       /* compression value:
    589                              -1: tEXt, none
    590                               0: zTXt, deflate
    591                               1: iTXt, none
    592                               2: iTXt, deflate  */
    593    png_charp key;          /* keyword, 1-79 character description of "text" */
    594    png_charp text;         /* comment, may be an empty string (ie "")
    595                               or a NULL pointer */
    596    png_size_t text_length; /* length of the text string */
    597 #ifdef PNG_iTXt_SUPPORTED
    598    png_size_t itxt_length; /* length of the itxt string */
    599    png_charp lang;         /* language code, 0-79 characters
    600                               or a NULL pointer */
    601    png_charp lang_key;     /* keyword translated UTF-8 string, 0 or more
    602                               chars or a NULL pointer */
    603 #endif
    604 } png_text;
    605 typedef png_text FAR * png_textp;
    606 typedef png_text FAR * FAR * png_textpp;
    607 #endif
    608 
    609 /* Supported compression types for text in PNG files (tEXt, and zTXt).
    610  * The values of the PNG_TEXT_COMPRESSION_ defines should NOT be changed. */
    611 #define PNG_TEXT_COMPRESSION_NONE_WR -3
    612 #define PNG_TEXT_COMPRESSION_zTXt_WR -2
    613 #define PNG_TEXT_COMPRESSION_NONE    -1
    614 #define PNG_TEXT_COMPRESSION_zTXt     0
    615 #define PNG_ITXT_COMPRESSION_NONE     1
    616 #define PNG_ITXT_COMPRESSION_zTXt     2
    617 #define PNG_TEXT_COMPRESSION_LAST     3  /* Not a valid value */
    618 
    619 /* png_time is a way to hold the time in an machine independent way.
    620  * Two conversions are provided, both from time_t and struct tm.  There
    621  * is no portable way to convert to either of these structures, as far
    622  * as I know.  If you know of a portable way, send it to me.  As a side
    623  * note - PNG has always been Year 2000 compliant!
    624  */
    625 typedef struct png_time_struct
    626 {
    627    png_uint_16 year; /* full year, as in, 1995 */
    628    png_byte month;   /* month of year, 1 - 12 */
    629    png_byte day;     /* day of month, 1 - 31 */
    630    png_byte hour;    /* hour of day, 0 - 23 */
    631    png_byte minute;  /* minute of hour, 0 - 59 */
    632    png_byte second;  /* second of minute, 0 - 60 (for leap seconds) */
    633 } png_time;
    634 typedef png_time FAR * png_timep;
    635 typedef png_time FAR * FAR * png_timepp;
    636 
    637 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
    638 /* png_unknown_chunk is a structure to hold queued chunks for which there is
    639  * no specific support.  The idea is that we can use this to queue
    640  * up private chunks for output even though the library doesn't actually
    641  * know about their semantics.
    642  */
    643 typedef struct png_unknown_chunk_t
    644 {
    645     png_byte name[5];
    646     png_byte *data;
    647     png_size_t size;
    648 
    649     /* libpng-using applications should NOT directly modify this byte. */
    650     png_byte location; /* mode of operation at read time */
    651 }
    652 png_unknown_chunk;
    653 typedef png_unknown_chunk FAR * png_unknown_chunkp;
    654 typedef png_unknown_chunk FAR * FAR * png_unknown_chunkpp;
    655 #endif
    656 
    657 /* png_info is a structure that holds the information in a PNG file so
    658  * that the application can find out the characteristics of the image.
    659  * If you are reading the file, this structure will tell you what is
    660  * in the PNG file.  If you are writing the file, fill in the information
    661  * you want to put into the PNG file, then call png_write_info().
    662  * The names chosen should be very close to the PNG specification, so
    663  * consult that document for information about the meaning of each field.
    664  *
    665  * With libpng < 0.95, it was only possible to directly set and read the
    666  * the values in the png_info_struct, which meant that the contents and
    667  * order of the values had to remain fixed.  With libpng 0.95 and later,
    668  * however, there are now functions that abstract the contents of
    669  * png_info_struct from the application, so this makes it easier to use
    670  * libpng with dynamic libraries, and even makes it possible to use
    671  * libraries that don't have all of the libpng ancillary chunk-handing
    672  * functionality.
    673  *
    674  * In any case, the order of the parameters in png_info_struct should NOT
    675  * be changed for as long as possible to keep compatibility with applications
    676  * that use the old direct-access method with png_info_struct.
    677  *
    678  * The following members may have allocated storage attached that should be
    679  * cleaned up before the structure is discarded: palette, trans, text,
    680  * pcal_purpose, pcal_units, pcal_params, hist, iccp_name, iccp_profile,
    681  * splt_palettes, scal_unit, row_pointers, and unknowns.   By default, these
    682  * are automatically freed when the info structure is deallocated, if they were
    683  * allocated internally by libpng.  This behavior can be changed by means
    684  * of the png_data_freer() function.
    685  *
    686  * More allocation details: all the chunk-reading functions that
    687  * change these members go through the corresponding png_set_*
    688  * functions.  A function to clear these members is available: see
    689  * png_free_data().  The png_set_* functions do not depend on being
    690  * able to point info structure members to any of the storage they are
    691  * passed (they make their own copies), EXCEPT that the png_set_text
    692  * functions use the same storage passed to them in the text_ptr or
    693  * itxt_ptr structure argument, and the png_set_rows and png_set_unknowns
    694  * functions do not make their own copies.
    695  */
    696 typedef struct png_info_struct
    697 {
    698    /* the following are necessary for every PNG file */
    699    png_uint_32 width;       /* width of image in pixels (from IHDR) */
    700    png_uint_32 height;      /* height of image in pixels (from IHDR) */
    701    png_uint_32 valid;       /* valid chunk data (see PNG_INFO_ below) */
    702    png_uint_32 rowbytes;    /* bytes needed to hold an untransformed row */
    703    png_colorp palette;      /* array of color values (valid & PNG_INFO_PLTE) */
    704    png_uint_16 num_palette; /* number of color entries in "palette" (PLTE) */
    705    png_uint_16 num_trans;   /* number of transparent palette color (tRNS) */
    706    png_byte bit_depth;      /* 1, 2, 4, 8, or 16 bits/channel (from IHDR) */
    707    png_byte color_type;     /* see PNG_COLOR_TYPE_ below (from IHDR) */
    708    /* The following three should have been named *_method not *_type */
    709    png_byte compression_type; /* must be PNG_COMPRESSION_TYPE_BASE (IHDR) */
    710    png_byte filter_type;    /* must be PNG_FILTER_TYPE_BASE (from IHDR) */
    711    png_byte interlace_type; /* One of PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */
    712 
    713    /* The following is informational only on read, and not used on writes. */
    714    png_byte channels;       /* number of data channels per pixel (1, 2, 3, 4) */
    715    png_byte pixel_depth;    /* number of bits per pixel */
    716    png_byte spare_byte;     /* to align the data, and for future use */
    717    png_byte signature[8];   /* magic bytes read by libpng from start of file */
    718 
    719    /* The rest of the data is optional.  If you are reading, check the
    720     * valid field to see if the information in these are valid.  If you
    721     * are writing, set the valid field to those chunks you want written,
    722     * and initialize the appropriate fields below.
    723     */
    724 
    725 #if defined(PNG_gAMA_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED)
    726    /* The gAMA chunk describes the gamma characteristics of the system
    727     * on which the image was created, normally in the range [1.0, 2.5].
    728     * Data is valid if (valid & PNG_INFO_gAMA) is non-zero.
    729     */
    730    float gamma; /* gamma value of image, if (valid & PNG_INFO_gAMA) */
    731 #endif
    732 
    733 #if defined(PNG_sRGB_SUPPORTED)
    734     /* GR-P, 0.96a */
    735     /* Data valid if (valid & PNG_INFO_sRGB) non-zero. */
    736    png_byte srgb_intent; /* sRGB rendering intent [0, 1, 2, or 3] */
    737 #endif
    738 
    739 #if defined(PNG_TEXT_SUPPORTED)
    740    /* The tEXt, and zTXt chunks contain human-readable textual data in
    741     * uncompressed, compressed, and optionally compressed forms, respectively.
    742     * The data in "text" is an array of pointers to uncompressed,
    743     * null-terminated C strings. Each chunk has a keyword that describes the
    744     * textual data contained in that chunk.  Keywords are not required to be
    745     * unique, and the text string may be empty.  Any number of text chunks may
    746     * be in an image.
    747     */
    748    int num_text; /* number of comments read/to write */
    749    int max_text; /* current size of text array */
    750    png_textp text; /* array of comments read/to write */
    751 #endif /* PNG_TEXT_SUPPORTED */
    752 
    753 #if defined(PNG_tIME_SUPPORTED)
    754    /* The tIME chunk holds the last time the displayed image data was
    755     * modified.  See the png_time struct for the contents of this struct.
    756     */
    757    png_time mod_time;
    758 #endif
    759 
    760 #if defined(PNG_sBIT_SUPPORTED)
    761    /* The sBIT chunk specifies the number of significant high-order bits
    762     * in the pixel data.  Values are in the range [1, bit_depth], and are
    763     * only specified for the channels in the pixel data.  The contents of
    764     * the low-order bits is not specified.  Data is valid if
    765     * (valid & PNG_INFO_sBIT) is non-zero.
    766     */
    767    png_color_8 sig_bit; /* significant bits in color channels */
    768 #endif
    769 
    770 #if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_EXPAND_SUPPORTED) || \
    771 defined(PNG_READ_BACKGROUND_SUPPORTED)
    772    /* The tRNS chunk supplies transparency data for paletted images and
    773     * other image types that don't need a full alpha channel.  There are
    774     * "num_trans" transparency values for a paletted image, stored in the
    775     * same order as the palette colors, starting from index 0.  Values
    776     * for the data are in the range [0, 255], ranging from fully transparent
    777     * to fully opaque, respectively.  For non-paletted images, there is a
    778     * single color specified that should be treated as fully transparent.
    779     * Data is valid if (valid & PNG_INFO_tRNS) is non-zero.
    780     */
    781    png_bytep trans; /* transparent values for paletted image */
    782    png_color_16 trans_values; /* transparent color for non-palette image */
    783 #endif
    784 
    785 #if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
    786    /* The bKGD chunk gives the suggested image background color if the
    787     * display program does not have its own background color and the image
    788     * is needs to composited onto a background before display.  The colors
    789     * in "background" are normally in the same color space/depth as the
    790     * pixel data.  Data is valid if (valid & PNG_INFO_bKGD) is non-zero.
    791     */
    792    png_color_16 background;
    793 #endif
    794 
    795 #if defined(PNG_oFFs_SUPPORTED)
    796    /* The oFFs chunk gives the offset in "offset_unit_type" units rightwards
    797     * and downwards from the top-left corner of the display, page, or other
    798     * application-specific co-ordinate space.  See the PNG_OFFSET_ defines
    799     * below for the unit types.  Valid if (valid & PNG_INFO_oFFs) non-zero.
    800     */
    801    png_int_32 x_offset; /* x offset on page */
    802    png_int_32 y_offset; /* y offset on page */
    803    png_byte offset_unit_type; /* offset units type */
    804 #endif
    805 
    806 #if defined(PNG_pHYs_SUPPORTED)
    807    /* The pHYs chunk gives the physical pixel density of the image for
    808     * display or printing in "phys_unit_type" units (see PNG_RESOLUTION_
    809     * defines below).  Data is valid if (valid & PNG_INFO_pHYs) is non-zero.
    810     */
    811    png_uint_32 x_pixels_per_unit; /* horizontal pixel density */
    812    png_uint_32 y_pixels_per_unit; /* vertical pixel density */
    813    png_byte phys_unit_type; /* resolution type (see PNG_RESOLUTION_ below) */
    814 #endif
    815 
    816 #if defined(PNG_hIST_SUPPORTED)
    817    /* The hIST chunk contains the relative frequency or importance of the
    818     * various palette entries, so that a viewer can intelligently select a
    819     * reduced-color palette, if required.  Data is an array of "num_palette"
    820     * values in the range [0,65535]. Data valid if (valid & PNG_INFO_hIST)
    821     * is non-zero.
    822     */
    823    png_uint_16p hist;
    824 #endif
    825 
    826 #ifdef PNG_cHRM_SUPPORTED
    827    /* The cHRM chunk describes the CIE color characteristics of the monitor
    828     * on which the PNG was created.  This data allows the viewer to do gamut
    829     * mapping of the input image to ensure that the viewer sees the same
    830     * colors in the image as the creator.  Values are in the range
    831     * [0.0, 0.8].  Data valid if (valid & PNG_INFO_cHRM) non-zero.
    832     */
    833 #ifdef PNG_FLOATING_POINT_SUPPORTED
    834    float x_white;
    835    float y_white;
    836    float x_red;
    837    float y_red;
    838    float x_green;
    839    float y_green;
    840    float x_blue;
    841    float y_blue;
    842 #endif
    843 #endif
    844 
    845 #if defined(PNG_pCAL_SUPPORTED)
    846    /* The pCAL chunk describes a transformation between the stored pixel
    847     * values and original physical data values used to create the image.
    848     * The integer range [0, 2^bit_depth - 1] maps to the floating-point
    849     * range given by [pcal_X0, pcal_X1], and are further transformed by a
    850     * (possibly non-linear) transformation function given by "pcal_type"
    851     * and "pcal_params" into "pcal_units".  Please see the PNG_EQUATION_
    852     * defines below, and the PNG-Group's PNG extensions document for a
    853     * complete description of the transformations and how they should be
    854     * implemented, and for a description of the ASCII parameter strings.
    855     * Data values are valid if (valid & PNG_INFO_pCAL) non-zero.
    856     */
    857    png_charp pcal_purpose;  /* pCAL chunk description string */
    858    png_int_32 pcal_X0;      /* minimum value */
    859    png_int_32 pcal_X1;      /* maximum value */
    860    png_charp pcal_units;    /* Latin-1 string giving physical units */
    861    png_charpp pcal_params;  /* ASCII strings containing parameter values */
    862    png_byte pcal_type;      /* equation type (see PNG_EQUATION_ below) */
    863    png_byte pcal_nparams;   /* number of parameters given in pcal_params */
    864 #endif
    865 
    866 /* New members added in libpng-1.0.6 */
    867 #ifdef PNG_FREE_ME_SUPPORTED
    868    png_uint_32 free_me;     /* flags items libpng is responsible for freeing */
    869 #endif
    870 
    871 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
    872    /* storage for unknown chunks that the library doesn't recognize. */
    873    png_unknown_chunkp unknown_chunks;
    874    png_size_t unknown_chunks_num;
    875 #endif
    876 
    877 #if defined(PNG_iCCP_SUPPORTED)
    878    /* iCCP chunk data. */
    879    png_charp iccp_name;     /* profile name */
    880    png_charp iccp_profile;  /* International Color Consortium profile data */
    881                             /* Note to maintainer: should be png_bytep */
    882    png_uint_32 iccp_proflen;  /* ICC profile data length */
    883    png_byte iccp_compression; /* Always zero */
    884 #endif
    885 
    886 #if defined(PNG_sPLT_SUPPORTED)
    887    /* data on sPLT chunks (there may be more than one). */
    888    png_sPLT_tp splt_palettes;
    889    png_uint_32 splt_palettes_num;
    890 #endif
    891 
    892 #if defined(PNG_sCAL_SUPPORTED)
    893    /* The sCAL chunk describes the actual physical dimensions of the
    894     * subject matter of the graphic.  The chunk contains a unit specification
    895     * a byte value, and two ASCII strings representing floating-point
    896     * values.  The values are width and height corresponsing to one pixel
    897     * in the image.  This external representation is converted to double
    898     * here.  Data values are valid if (valid & PNG_INFO_sCAL) is non-zero.
    899     */
    900    png_byte scal_unit;         /* unit of physical scale */
    901 #ifdef PNG_FLOATING_POINT_SUPPORTED
    902    double scal_pixel_width;    /* width of one pixel */
    903    double scal_pixel_height;   /* height of one pixel */
    904 #endif
    905 #ifdef PNG_FIXED_POINT_SUPPORTED
    906    png_charp scal_s_width;     /* string containing height */
    907    png_charp scal_s_height;    /* string containing width */
    908 #endif
    909 #endif
    910 
    911 #if defined(PNG_INFO_IMAGE_SUPPORTED)
    912    /* Memory has been allocated if (valid & PNG_ALLOCATED_INFO_ROWS) non-zero */
    913    /* Data valid if (valid & PNG_INFO_IDAT) non-zero */
    914    png_bytepp row_pointers;        /* the image bits */
    915 #endif
    916 
    917 #if defined(PNG_FIXED_POINT_SUPPORTED) && defined(PNG_gAMA_SUPPORTED)
    918    png_fixed_point int_gamma; /* gamma of image, if (valid & PNG_INFO_gAMA) */
    919 #endif
    920 
    921 #if defined(PNG_cHRM_SUPPORTED) && defined(PNG_FIXED_POINT_SUPPORTED)
    922    png_fixed_point int_x_white;
    923    png_fixed_point int_y_white;
    924    png_fixed_point int_x_red;
    925    png_fixed_point int_y_red;
    926    png_fixed_point int_x_green;
    927    png_fixed_point int_y_green;
    928    png_fixed_point int_x_blue;
    929    png_fixed_point int_y_blue;
    930 #endif
    931 
    932 } png_info;
    933 
    934 typedef png_info FAR * png_infop;
    935 typedef png_info FAR * FAR * png_infopp;
    936 
    937 /* Maximum positive integer used in PNG is (2^31)-1 */
    938 #define PNG_UINT_31_MAX ((png_uint_32)0x7fffffffL)
    939 #define PNG_UINT_32_MAX ((png_uint_32)(-1))
    940 #define PNG_SIZE_MAX ((png_size_t)(-1))
    941 #if defined(PNG_1_0_X) || defined (PNG_1_2_X)
    942 /* PNG_MAX_UINT is deprecated; use PNG_UINT_31_MAX instead. */
    943 #define PNG_MAX_UINT PNG_UINT_31_MAX
    944 #endif
    945 
    946 /* These describe the color_type field in png_info. */
    947 /* color type masks */
    948 #define PNG_COLOR_MASK_PALETTE    1
    949 #define PNG_COLOR_MASK_COLOR      2
    950 #define PNG_COLOR_MASK_ALPHA      4
    951 
    952 /* color types.  Note that not all combinations are legal */
    953 #define PNG_COLOR_TYPE_GRAY 0
    954 #define PNG_COLOR_TYPE_PALETTE  (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
    955 #define PNG_COLOR_TYPE_RGB        (PNG_COLOR_MASK_COLOR)
    956 #define PNG_COLOR_TYPE_RGB_ALPHA  (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
    957 #define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
    958 /* aliases */
    959 #define PNG_COLOR_TYPE_RGBA  PNG_COLOR_TYPE_RGB_ALPHA
    960 #define PNG_COLOR_TYPE_GA  PNG_COLOR_TYPE_GRAY_ALPHA
    961 
    962 /* This is for compression type. PNG 1.0-1.2 only define the single type. */
    963 #define PNG_COMPRESSION_TYPE_BASE 0 /* Deflate method 8, 32K window */
    964 #define PNG_COMPRESSION_TYPE_DEFAULT PNG_COMPRESSION_TYPE_BASE
    965 
    966 /* This is for filter type. PNG 1.0-1.2 only define the single type. */
    967 #define PNG_FILTER_TYPE_BASE      0 /* Single row per-byte filtering */
    968 #define PNG_INTRAPIXEL_DIFFERENCING 64 /* Used only in MNG datastreams */
    969 #define PNG_FILTER_TYPE_DEFAULT   PNG_FILTER_TYPE_BASE
    970 
    971 /* These are for the interlacing type.  These values should NOT be changed. */
    972 #define PNG_INTERLACE_NONE        0 /* Non-interlaced image */
    973 #define PNG_INTERLACE_ADAM7       1 /* Adam7 interlacing */
    974 #define PNG_INTERLACE_LAST        2 /* Not a valid value */
    975 
    976 /* These are for the oFFs chunk.  These values should NOT be changed. */
    977 #define PNG_OFFSET_PIXEL          0 /* Offset in pixels */
    978 #define PNG_OFFSET_MICROMETER     1 /* Offset in micrometers (1/10^6 meter) */
    979 #define PNG_OFFSET_LAST           2 /* Not a valid value */
    980 
    981 /* These are for the pCAL chunk.  These values should NOT be changed. */
    982 #define PNG_EQUATION_LINEAR       0 /* Linear transformation */
    983 #define PNG_EQUATION_BASE_E       1 /* Exponential base e transform */
    984 #define PNG_EQUATION_ARBITRARY    2 /* Arbitrary base exponential transform */
    985 #define PNG_EQUATION_HYPERBOLIC   3 /* Hyperbolic sine transformation */
    986 #define PNG_EQUATION_LAST         4 /* Not a valid value */
    987 
    988 /* These are for the sCAL chunk.  These values should NOT be changed. */
    989 #define PNG_SCALE_UNKNOWN         0 /* unknown unit (image scale) */
    990 #define PNG_SCALE_METER           1 /* meters per pixel */
    991 #define PNG_SCALE_RADIAN          2 /* radians per pixel */
    992 #define PNG_SCALE_LAST            3 /* Not a valid value */
    993 
    994 /* These are for the pHYs chunk.  These values should NOT be changed. */
    995 #define PNG_RESOLUTION_UNKNOWN    0 /* pixels/unknown unit (aspect ratio) */
    996 #define PNG_RESOLUTION_METER      1 /* pixels/meter */
    997 #define PNG_RESOLUTION_LAST       2 /* Not a valid value */
    998 
    999 /* These are for the sRGB chunk.  These values should NOT be changed. */
   1000 #define PNG_sRGB_INTENT_PERCEPTUAL 0
   1001 #define PNG_sRGB_INTENT_RELATIVE   1
   1002 #define PNG_sRGB_INTENT_SATURATION 2
   1003 #define PNG_sRGB_INTENT_ABSOLUTE   3
   1004 #define PNG_sRGB_INTENT_LAST       4 /* Not a valid value */
   1005 
   1006 /* This is for text chunks */
   1007 #define PNG_KEYWORD_MAX_LENGTH     79
   1008 
   1009 /* Maximum number of entries in PLTE/sPLT/tRNS arrays */
   1010 #define PNG_MAX_PALETTE_LENGTH    256
   1011 
   1012 /* These determine if an ancillary chunk's data has been successfully read
   1013  * from the PNG header, or if the application has filled in the corresponding
   1014  * data in the info_struct to be written into the output file.  The values
   1015  * of the PNG_INFO_<chunk> defines should NOT be changed.
   1016  */
   1017 #define PNG_INFO_gAMA 0x0001
   1018 #define PNG_INFO_sBIT 0x0002
   1019 #define PNG_INFO_cHRM 0x0004
   1020 #define PNG_INFO_PLTE 0x0008
   1021 #define PNG_INFO_tRNS 0x0010
   1022 #define PNG_INFO_bKGD 0x0020
   1023 #define PNG_INFO_hIST 0x0040
   1024 #define PNG_INFO_pHYs 0x0080
   1025 #define PNG_INFO_oFFs 0x0100
   1026 #define PNG_INFO_tIME 0x0200
   1027 #define PNG_INFO_pCAL 0x0400
   1028 #define PNG_INFO_sRGB 0x0800   /* GR-P, 0.96a */
   1029 #define PNG_INFO_iCCP 0x1000   /* ESR, 1.0.6 */
   1030 #define PNG_INFO_sPLT 0x2000   /* ESR, 1.0.6 */
   1031 #define PNG_INFO_sCAL 0x4000   /* ESR, 1.0.6 */
   1032 #define PNG_INFO_IDAT 0x8000L  /* ESR, 1.0.6 */
   1033 
   1034 /* This is used for the transformation routines, as some of them
   1035  * change these values for the row.  It also should enable using
   1036  * the routines for other purposes.
   1037  */
   1038 typedef struct png_row_info_struct
   1039 {
   1040    png_uint_32 width; /* width of row */
   1041    png_uint_32 rowbytes; /* number of bytes in row */
   1042    png_byte color_type; /* color type of row */
   1043    png_byte bit_depth; /* bit depth of row */
   1044    png_byte channels; /* number of channels (1, 2, 3, or 4) */
   1045    png_byte pixel_depth; /* bits per pixel (depth * channels) */
   1046 } png_row_info;
   1047 
   1048 typedef png_row_info FAR * png_row_infop;
   1049 typedef png_row_info FAR * FAR * png_row_infopp;
   1050 
   1051 /* These are the function types for the I/O functions and for the functions
   1052  * that allow the user to override the default I/O functions with his or her
   1053  * own.  The png_error_ptr type should match that of user-supplied warning
   1054  * and error functions, while the png_rw_ptr type should match that of the
   1055  * user read/write data functions.
   1056  */
   1057 typedef struct png_struct_def png_struct;
   1058 typedef png_struct FAR * png_structp;
   1059 
   1060 typedef void (PNGAPI *png_error_ptr) PNGARG((png_structp, png_const_charp));
   1061 typedef void (PNGAPI *png_rw_ptr) PNGARG((png_structp, png_bytep, png_size_t));
   1062 typedef void (PNGAPI *png_flush_ptr) PNGARG((png_structp));
   1063 typedef void (PNGAPI *png_read_status_ptr) PNGARG((png_structp, png_uint_32,
   1064    int));
   1065 typedef void (PNGAPI *png_write_status_ptr) PNGARG((png_structp, png_uint_32,
   1066    int));
   1067 
   1068 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
   1069 typedef void (PNGAPI *png_progressive_info_ptr) PNGARG((png_structp, png_infop));
   1070 typedef void (PNGAPI *png_progressive_end_ptr) PNGARG((png_structp, png_infop));
   1071 typedef void (PNGAPI *png_progressive_row_ptr) PNGARG((png_structp, png_bytep,
   1072    png_uint_32, int));
   1073 #endif
   1074 
   1075 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
   1076     defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) || \
   1077     defined(PNG_LEGACY_SUPPORTED)
   1078 typedef void (PNGAPI *png_user_transform_ptr) PNGARG((png_structp,
   1079     png_row_infop, png_bytep));
   1080 #endif
   1081 
   1082 #if defined(PNG_USER_CHUNKS_SUPPORTED)
   1083 typedef int (PNGAPI *png_user_chunk_ptr) PNGARG((png_structp, png_unknown_chunkp));
   1084 #endif
   1085 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
   1086 typedef void (PNGAPI *png_unknown_chunk_ptr) PNGARG((png_structp));
   1087 #endif
   1088 
   1089 /* Transform masks for the high-level interface */
   1090 #define PNG_TRANSFORM_IDENTITY       0x0000    /* read and write */
   1091 #define PNG_TRANSFORM_STRIP_16       0x0001    /* read only */
   1092 #define PNG_TRANSFORM_STRIP_ALPHA    0x0002    /* read only */
   1093 #define PNG_TRANSFORM_PACKING        0x0004    /* read and write */
   1094 #define PNG_TRANSFORM_PACKSWAP       0x0008    /* read and write */
   1095 #define PNG_TRANSFORM_EXPAND         0x0010    /* read only */
   1096 #define PNG_TRANSFORM_INVERT_MONO    0x0020    /* read and write */
   1097 #define PNG_TRANSFORM_SHIFT          0x0040    /* read and write */
   1098 #define PNG_TRANSFORM_BGR            0x0080    /* read and write */
   1099 #define PNG_TRANSFORM_SWAP_ALPHA     0x0100    /* read and write */
   1100 #define PNG_TRANSFORM_SWAP_ENDIAN    0x0200    /* read and write */
   1101 #define PNG_TRANSFORM_INVERT_ALPHA   0x0400    /* read and write */
   1102 #define PNG_TRANSFORM_STRIP_FILLER   0x0800    /* WRITE only */
   1103 
   1104 /* Flags for MNG supported features */
   1105 #define PNG_FLAG_MNG_EMPTY_PLTE     0x01
   1106 #define PNG_FLAG_MNG_FILTER_64      0x04
   1107 #define PNG_ALL_MNG_FEATURES        0x05
   1108 
   1109 typedef png_voidp (*png_malloc_ptr) PNGARG((png_structp, png_size_t));
   1110 typedef void (*png_free_ptr) PNGARG((png_structp, png_voidp));
   1111 
   1112 /* The structure that holds the information to read and write PNG files.
   1113  * The only people who need to care about what is inside of this are the
   1114  * people who will be modifying the library for their own special needs.
   1115  * It should NOT be accessed directly by an application, except to store
   1116  * the jmp_buf.
   1117  */
   1118 
   1119 struct png_struct_def
   1120 {
   1121 #ifdef PNG_SETJMP_SUPPORTED
   1122    jmp_buf jmpbuf;            /* used in png_error */
   1123 #endif
   1124    png_error_ptr error_fn;    /* function for printing errors and aborting */
   1125    png_error_ptr warning_fn;  /* function for printing warnings */
   1126    png_voidp error_ptr;       /* user supplied struct for error functions */
   1127    png_rw_ptr write_data_fn;  /* function for writing output data */
   1128    png_rw_ptr read_data_fn;   /* function for reading input data */
   1129    png_voidp io_ptr;          /* ptr to application struct for I/O functions */
   1130 
   1131 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
   1132    png_user_transform_ptr read_user_transform_fn; /* user read transform */
   1133 #endif
   1134 
   1135 #if defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
   1136    png_user_transform_ptr write_user_transform_fn; /* user write transform */
   1137 #endif
   1138 
   1139 /* These were added in libpng-1.0.2 */
   1140 #if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
   1141 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
   1142     defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
   1143    png_voidp user_transform_ptr; /* user supplied struct for user transform */
   1144    png_byte user_transform_depth;    /* bit depth of user transformed pixels */
   1145    png_byte user_transform_channels; /* channels in user transformed pixels */
   1146 #endif
   1147 #endif
   1148 
   1149    png_uint_32 mode;          /* tells us where we are in the PNG file */
   1150    png_uint_32 flags;         /* flags indicating various things to libpng */
   1151    png_uint_32 transformations; /* which transformations to perform */
   1152 
   1153    z_stream zstream;          /* pointer to decompression structure (below) */
   1154    png_bytep zbuf;            /* buffer for zlib */
   1155    png_size_t zbuf_size;      /* size of zbuf */
   1156    int zlib_level;            /* holds zlib compression level */
   1157    int zlib_method;           /* holds zlib compression method */
   1158    int zlib_window_bits;      /* holds zlib compression window bits */
   1159    int zlib_mem_level;        /* holds zlib compression memory level */
   1160    int zlib_strategy;         /* holds zlib compression strategy */
   1161 
   1162    png_uint_32 width;         /* width of image in pixels */
   1163    png_uint_32 height;        /* height of image in pixels */
   1164    png_uint_32 num_rows;      /* number of rows in current pass */
   1165    png_uint_32 usr_width;     /* width of row at start of write */
   1166    png_uint_32 rowbytes;      /* size of row in bytes */
   1167    png_uint_32 irowbytes;     /* size of current interlaced row in bytes */
   1168    png_uint_32 iwidth;        /* width of current interlaced row in pixels */
   1169    png_uint_32 row_number;    /* current row in interlace pass */
   1170    png_bytep prev_row;        /* buffer to save previous (unfiltered) row */
   1171    png_bytep row_buf;         /* buffer to save current (unfiltered) row */
   1172    png_bytep sub_row;         /* buffer to save "sub" row when filtering */
   1173    png_bytep up_row;          /* buffer to save "up" row when filtering */
   1174    png_bytep avg_row;         /* buffer to save "avg" row when filtering */
   1175    png_bytep paeth_row;       /* buffer to save "Paeth" row when filtering */
   1176    png_row_info row_info;     /* used for transformation routines */
   1177 
   1178    png_uint_32 idat_size;     /* current IDAT size for read */
   1179    png_uint_32 crc;           /* current chunk CRC value */
   1180    png_colorp palette;        /* palette from the input file */
   1181    png_uint_16 num_palette;   /* number of color entries in palette */
   1182    png_uint_16 num_trans;     /* number of transparency values */
   1183    png_byte chunk_name[5];    /* null-terminated name of current chunk */
   1184    png_byte compression;      /* file compression type (always 0) */
   1185    png_byte filter;           /* file filter type (always 0) */
   1186    png_byte interlaced;       /* PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */
   1187    png_byte pass;             /* current interlace pass (0 - 6) */
   1188    png_byte do_filter;        /* row filter flags (see PNG_FILTER_ below ) */
   1189    png_byte color_type;       /* color type of file */
   1190    png_byte bit_depth;        /* bit depth of file */
   1191    png_byte usr_bit_depth;    /* bit depth of users row */
   1192    png_byte pixel_depth;      /* number of bits per pixel */
   1193    png_byte channels;         /* number of channels in file */
   1194    png_byte usr_channels;     /* channels at start of write */
   1195    png_byte sig_bytes;        /* magic bytes read/written from start of file */
   1196 
   1197 #if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
   1198 #ifdef PNG_LEGACY_SUPPORTED
   1199    png_byte filler;           /* filler byte for pixel expansion */
   1200 #else
   1201    png_uint_16 filler;           /* filler bytes for pixel expansion */
   1202 #endif
   1203 #endif
   1204 
   1205 #if defined(PNG_bKGD_SUPPORTED)
   1206    png_byte background_gamma_type;
   1207 #  ifdef PNG_FLOATING_POINT_SUPPORTED
   1208    float background_gamma;
   1209 #  endif
   1210    png_color_16 background;   /* background color in screen gamma space */
   1211 #if defined(PNG_READ_GAMMA_SUPPORTED)
   1212    png_color_16 background_1; /* background normalized to gamma 1.0 */
   1213 #endif
   1214 #endif /* PNG_bKGD_SUPPORTED */
   1215 
   1216 #if defined(PNG_WRITE_FLUSH_SUPPORTED)
   1217    png_flush_ptr output_flush_fn;/* Function for flushing output */
   1218    png_uint_32 flush_dist;    /* how many rows apart to flush, 0 - no flush */
   1219    png_uint_32 flush_rows;    /* number of rows written since last flush */
   1220 #endif
   1221 
   1222 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
   1223    int gamma_shift;      /* number of "insignificant" bits 16-bit gamma */
   1224 #ifdef PNG_FLOATING_POINT_SUPPORTED
   1225    float gamma;          /* file gamma value */
   1226    float screen_gamma;   /* screen gamma value (display_exponent) */
   1227 #endif
   1228 #endif
   1229 
   1230 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
   1231    png_bytep gamma_table;     /* gamma table for 8-bit depth files */
   1232    png_bytep gamma_from_1;    /* converts from 1.0 to screen */
   1233    png_bytep gamma_to_1;      /* converts from file to 1.0 */
   1234    png_uint_16pp gamma_16_table; /* gamma table for 16-bit depth files */
   1235    png_uint_16pp gamma_16_from_1; /* converts from 1.0 to screen */
   1236    png_uint_16pp gamma_16_to_1; /* converts from file to 1.0 */
   1237 #endif
   1238 
   1239 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_sBIT_SUPPORTED)
   1240    png_color_8 sig_bit;       /* significant bits in each available channel */
   1241 #endif
   1242 
   1243 #if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
   1244    png_color_8 shift;         /* shift for significant bit tranformation */
   1245 #endif
   1246 
   1247 #if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) \
   1248  || defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
   1249    png_bytep trans;           /* transparency values for paletted files */
   1250    png_color_16 trans_values; /* transparency values for non-paletted files */
   1251 #endif
   1252 
   1253    png_read_status_ptr read_row_fn;   /* called after each row is decoded */
   1254    png_write_status_ptr write_row_fn; /* called after each row is encoded */
   1255 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
   1256    png_progressive_info_ptr info_fn; /* called after header data fully read */
   1257    png_progressive_row_ptr row_fn;   /* called after each prog. row is decoded */
   1258    png_progressive_end_ptr end_fn;   /* called after image is complete */
   1259    png_bytep save_buffer_ptr;        /* current location in save_buffer */
   1260    png_bytep save_buffer;            /* buffer for previously read data */
   1261    png_bytep current_buffer_ptr;     /* current location in current_buffer */
   1262    png_bytep current_buffer;         /* buffer for recently used data */
   1263    png_uint_32 push_length;          /* size of current input chunk */
   1264    png_uint_32 skip_length;          /* bytes to skip in input data */
   1265    png_size_t save_buffer_size;      /* amount of data now in save_buffer */
   1266    png_size_t save_buffer_max;       /* total size of save_buffer */
   1267    png_size_t buffer_size;           /* total amount of available input data */
   1268    png_size_t current_buffer_size;   /* amount of data now in current_buffer */
   1269    int process_mode;                 /* what push library is currently doing */
   1270    int cur_palette;                  /* current push library palette index */
   1271 
   1272 #  if defined(PNG_TEXT_SUPPORTED)
   1273      png_size_t current_text_size;   /* current size of text input data */
   1274      png_size_t current_text_left;   /* how much text left to read in input */
   1275      png_charp current_text;         /* current text chunk buffer */
   1276      png_charp current_text_ptr;     /* current location in current_text */
   1277 #  endif /* PNG_PROGRESSIVE_READ_SUPPORTED && PNG_TEXT_SUPPORTED */
   1278 
   1279 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
   1280 
   1281 #if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
   1282 /* for the Borland special 64K segment handler */
   1283    png_bytepp offset_table_ptr;
   1284    png_bytep offset_table;
   1285    png_uint_16 offset_table_number;
   1286    png_uint_16 offset_table_count;
   1287    png_uint_16 offset_table_count_free;
   1288 #endif
   1289 
   1290 #if defined(PNG_READ_DITHER_SUPPORTED)
   1291    png_bytep palette_lookup;         /* lookup table for dithering */
   1292    png_bytep dither_index;           /* index translation for palette files */
   1293 #endif
   1294 
   1295 #if defined(PNG_READ_DITHER_SUPPORTED) || defined(PNG_hIST_SUPPORTED)
   1296    png_uint_16p hist;                /* histogram */
   1297 #endif
   1298 
   1299 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
   1300    png_byte heuristic_method;        /* heuristic for row filter selection */
   1301    png_byte num_prev_filters;        /* number of weights for previous rows */
   1302    png_bytep prev_filters;           /* filter type(s) of previous row(s) */
   1303    png_uint_16p filter_weights;      /* weight(s) for previous line(s) */
   1304    png_uint_16p inv_filter_weights;  /* 1/weight(s) for previous line(s) */
   1305    png_uint_16p filter_costs;        /* relative filter calculation cost */
   1306    png_uint_16p inv_filter_costs;    /* 1/relative filter calculation cost */
   1307 #endif
   1308 
   1309 #if defined(PNG_TIME_RFC1123_SUPPORTED)
   1310    png_charp time_buffer;            /* String to hold RFC 1123 time text */
   1311 #endif
   1312 
   1313 /* New members added in libpng-1.0.6 */
   1314 
   1315 #ifdef PNG_FREE_ME_SUPPORTED
   1316    png_uint_32 free_me;       /* flags items libpng is responsible for freeing */
   1317 #endif
   1318 
   1319 #if defined(PNG_USER_CHUNKS_SUPPORTED)
   1320    png_voidp user_chunk_ptr;
   1321    png_user_chunk_ptr read_user_chunk_fn; /* user read chunk handler */
   1322 #endif
   1323 
   1324 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
   1325    int num_chunk_list;
   1326    png_bytep chunk_list;
   1327 #endif
   1328 
   1329 /* New members added in libpng-1.0.3 */
   1330 #if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
   1331    png_byte rgb_to_gray_status;
   1332    /* These were changed from png_byte in libpng-1.0.6 */
   1333    png_uint_16 rgb_to_gray_red_coeff;
   1334    png_uint_16 rgb_to_gray_green_coeff;
   1335    png_uint_16 rgb_to_gray_blue_coeff;
   1336 #endif
   1337 
   1338 /* New member added in libpng-1.0.4 (renamed in 1.0.9) */
   1339 #if defined(PNG_MNG_FEATURES_SUPPORTED) || \
   1340     defined(PNG_READ_EMPTY_PLTE_SUPPORTED) || \
   1341     defined(PNG_WRITE_EMPTY_PLTE_SUPPORTED)
   1342 /* changed from png_byte to png_uint_32 at version 1.2.0 */
   1343 #ifdef PNG_1_0_X
   1344    png_byte mng_features_permitted;
   1345 #else
   1346    png_uint_32 mng_features_permitted;
   1347 #endif /* PNG_1_0_X */
   1348 #endif
   1349 
   1350 /* New member added in libpng-1.0.7 */
   1351 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
   1352    png_fixed_point int_gamma;
   1353 #endif
   1354 
   1355 /* New member added in libpng-1.0.9, ifdef'ed out in 1.0.12, enabled in 1.2.0 */
   1356 #if defined(PNG_MNG_FEATURES_SUPPORTED)
   1357    png_byte filter_type;
   1358 #endif
   1359 
   1360 #if defined(PNG_1_0_X)
   1361 /* New member added in libpng-1.0.10, ifdef'ed out in 1.2.0 */
   1362    png_uint_32 row_buf_size;
   1363 #endif
   1364 
   1365 /* New members added in libpng-1.2.0 */
   1366 #if defined(PNG_ASSEMBLER_CODE_SUPPORTED)
   1367 #  if !defined(PNG_1_0_X)
   1368 #    if defined(PNG_MMX_CODE_SUPPORTED)
   1369    png_byte     mmx_bitdepth_threshold;
   1370    png_uint_32  mmx_rowbytes_threshold;
   1371 #    endif
   1372    png_uint_32  asm_flags;
   1373 #  endif
   1374 #endif
   1375 
   1376 /* New members added in libpng-1.0.2 but first enabled by default in 1.2.0 */
   1377 #ifdef PNG_USER_MEM_SUPPORTED
   1378    png_voidp mem_ptr;                /* user supplied struct for mem functions */
   1379    png_malloc_ptr malloc_fn;         /* function for allocating memory */
   1380    png_free_ptr free_fn;             /* function for freeing memory */
   1381 #endif
   1382 
   1383 /* New member added in libpng-1.0.13 and 1.2.0 */
   1384    png_bytep big_row_buf;         /* buffer to save current (unfiltered) row */
   1385 
   1386 #if defined(PNG_READ_DITHER_SUPPORTED)
   1387 /* The following three members were added at version 1.0.14 and 1.2.4 */
   1388    png_bytep dither_sort;            /* working sort array */
   1389    png_bytep index_to_palette;       /* where the original index currently is */
   1390                                      /* in the palette */
   1391    png_bytep palette_to_index;       /* which original index points to this */
   1392                                      /* palette color */
   1393 #endif
   1394 
   1395 /* New members added in libpng-1.0.16 and 1.2.6 */
   1396    png_byte compression_type;
   1397 
   1398 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
   1399    png_uint_32 user_width_max;
   1400    png_uint_32 user_height_max;
   1401 #endif
   1402 
   1403 /* New member added in libpng-1.0.25 and 1.2.17 */
   1404 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
   1405    /* storage for unknown chunk that the library doesn't recognize. */
   1406    png_unknown_chunk unknown_chunk;
   1407 #endif
   1408 };
   1409 
   1410 
   1411 /* This triggers a compiler error in png.c, if png.c and png.h
   1412  * do not agree upon the version number.
   1413  */
   1414 typedef png_structp version_1_2_19;
   1415 
   1416 typedef png_struct FAR * FAR * png_structpp;
   1417 
   1418 /* Here are the function definitions most commonly used.  This is not
   1419  * the place to find out how to use libpng.  See libpng.txt for the
   1420  * full explanation, see example.c for the summary.  This just provides
   1421  * a simple one line description of the use of each function.
   1422  */
   1423 
   1424 /* Returns the version number of the library */
   1425 extern PNG_EXPORT(png_uint_32,png_access_version_number) PNGARG((void));
   1426 
   1427 /* Tell lib we have already handled the first <num_bytes> magic bytes.
   1428  * Handling more than 8 bytes from the beginning of the file is an error.
   1429  */
   1430 extern PNG_EXPORT(void,png_set_sig_bytes) PNGARG((png_structp png_ptr,
   1431    int num_bytes));
   1432 
   1433 /* Check sig[start] through sig[start + num_to_check - 1] to see if it's a
   1434  * PNG file.  Returns zero if the supplied bytes match the 8-byte PNG
   1435  * signature, and non-zero otherwise.  Having num_to_check == 0 or
   1436  * start > 7 will always fail (ie return non-zero).
   1437  */
   1438 extern PNG_EXPORT(int,png_sig_cmp) PNGARG((png_bytep sig, png_size_t start,
   1439    png_size_t num_to_check));
   1440 
   1441 /* Simple signature checking function.  This is the same as calling
   1442  * png_check_sig(sig, n) := !png_sig_cmp(sig, 0, n).
   1443  */
   1444 extern PNG_EXPORT(int,png_check_sig) PNGARG((png_bytep sig, int num));
   1445 
   1446 /* Allocate and initialize png_ptr struct for reading, and any other memory. */
   1447 extern PNG_EXPORT(png_structp,png_create_read_struct)
   1448    PNGARG((png_const_charp user_png_ver, png_voidp error_ptr,
   1449    png_error_ptr error_fn, png_error_ptr warn_fn));
   1450 
   1451 /* Allocate and initialize png_ptr struct for writing, and any other memory */
   1452 extern PNG_EXPORT(png_structp,png_create_write_struct)
   1453    PNGARG((png_const_charp user_png_ver, png_voidp error_ptr,
   1454    png_error_ptr error_fn, png_error_ptr warn_fn));
   1455 
   1456 #ifdef PNG_WRITE_SUPPORTED
   1457 extern PNG_EXPORT(png_uint_32,png_get_compression_buffer_size)
   1458    PNGARG((png_structp png_ptr));
   1459 #endif
   1460 
   1461 #ifdef PNG_WRITE_SUPPORTED
   1462 extern PNG_EXPORT(void,png_set_compression_buffer_size)
   1463    PNGARG((png_structp png_ptr, png_uint_32 size));
   1464 #endif
   1465 
   1466 /* Reset the compression stream */
   1467 extern PNG_EXPORT(int,png_reset_zstream) PNGARG((png_structp png_ptr));
   1468 
   1469 /* New functions added in libpng-1.0.2 (not enabled by default until 1.2.0) */
   1470 #ifdef PNG_USER_MEM_SUPPORTED
   1471 extern PNG_EXPORT(png_structp,png_create_read_struct_2)
   1472    PNGARG((png_const_charp user_png_ver, png_voidp error_ptr,
   1473    png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
   1474    png_malloc_ptr malloc_fn, png_free_ptr free_fn));
   1475 extern PNG_EXPORT(png_structp,png_create_write_struct_2)
   1476    PNGARG((png_const_charp user_png_ver, png_voidp error_ptr,
   1477    png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
   1478    png_malloc_ptr malloc_fn, png_free_ptr free_fn));
   1479 #endif
   1480 
   1481 /* Write a PNG chunk - size, type, (optional) data, CRC. */
   1482 extern PNG_EXPORT(void,png_write_chunk) PNGARG((png_structp png_ptr,
   1483    png_bytep chunk_name, png_bytep data, png_size_t length));
   1484 
   1485 /* Write the start of a PNG chunk - length and chunk name. */
   1486 extern PNG_EXPORT(void,png_write_chunk_start) PNGARG((png_structp png_ptr,
   1487    png_bytep chunk_name, png_uint_32 length));
   1488 
   1489 /* Write the data of a PNG chunk started with png_write_chunk_start(). */
   1490 extern PNG_EXPORT(void,png_write_chunk_data) PNGARG((png_structp png_ptr,
   1491    png_bytep data, png_size_t length));
   1492 
   1493 /* Finish a chunk started with png_write_chunk_start() (includes CRC). */
   1494 extern PNG_EXPORT(void,png_write_chunk_end) PNGARG((png_structp png_ptr));
   1495 
   1496 /* Allocate and initialize the info structure */
   1497 extern PNG_EXPORT(png_infop,png_create_info_struct)
   1498    PNGARG((png_structp png_ptr));
   1499 
   1500 #if defined(PNG_1_0_X) || defined (PNG_1_2_X)
   1501 /* Initialize the info structure (old interface - DEPRECATED) */
   1502 extern PNG_EXPORT(void,png_info_init) PNGARG((png_infop info_ptr));
   1503 #undef png_info_init
   1504 #define png_info_init(info_ptr) png_info_init_3(&info_ptr,\
   1505     png_sizeof(png_info));
   1506 #endif
   1507 
   1508 extern PNG_EXPORT(void,png_info_init_3) PNGARG((png_infopp info_ptr,
   1509     png_size_t png_info_struct_size));
   1510 
   1511 /* Writes all the PNG information before the image. */
   1512 extern PNG_EXPORT(void,png_write_info_before_PLTE) PNGARG((png_structp png_ptr,
   1513    png_infop info_ptr));
   1514 extern PNG_EXPORT(void,png_write_info) PNGARG((png_structp png_ptr,
   1515    png_infop info_ptr));
   1516 
   1517 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
   1518 /* read the information before the actual image data. */
   1519 extern PNG_EXPORT(void,png_read_info) PNGARG((png_structp png_ptr,
   1520    png_infop info_ptr));
   1521 #endif
   1522 
   1523 #if defined(PNG_TIME_RFC1123_SUPPORTED)
   1524 extern PNG_EXPORT(png_charp,png_convert_to_rfc1123)
   1525    PNGARG((png_structp png_ptr, png_timep ptime));
   1526 #endif
   1527 
   1528 #if !defined(_WIN32_WCE)
   1529 /* "time.h" functions are not supported on WindowsCE */
   1530 #if defined(PNG_WRITE_tIME_SUPPORTED)
   1531 /* convert from a struct tm to png_time */
   1532 extern PNG_EXPORT(void,png_convert_from_struct_tm) PNGARG((png_timep ptime,
   1533    struct tm FAR * ttime));
   1534 
   1535 /* convert from time_t to png_time.  Uses gmtime() */
   1536 extern PNG_EXPORT(void,png_convert_from_time_t) PNGARG((png_timep ptime,
   1537    time_t ttime));
   1538 #endif /* PNG_WRITE_tIME_SUPPORTED */
   1539 #endif /* _WIN32_WCE */
   1540 
   1541 #if defined(PNG_READ_EXPAND_SUPPORTED)
   1542 /* Expand data to 24-bit RGB, or 8-bit grayscale, with alpha if available. */
   1543 extern PNG_EXPORT(void,png_set_expand) PNGARG((png_structp png_ptr));
   1544 #if !defined(PNG_1_0_X)
   1545 extern PNG_EXPORT(void,png_set_expand_gray_1_2_4_to_8) PNGARG((png_structp
   1546   png_ptr));
   1547 #endif
   1548 extern PNG_EXPORT(void,png_set_palette_to_rgb) PNGARG((png_structp png_ptr));
   1549 extern PNG_EXPORT(void,png_set_tRNS_to_alpha) PNGARG((png_structp png_ptr));
   1550 #if defined(PNG_1_0_X) || defined (PNG_1_2_X)
   1551 /* Deprecated */
   1552 extern PNG_EXPORT(void,png_set_gray_1_2_4_to_8) PNGARG((png_structp png_ptr));
   1553 #endif
   1554 #endif
   1555 
   1556 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
   1557 /* Use blue, green, red order for pixels. */
   1558 extern PNG_EXPORT(void,png_set_bgr) PNGARG((png_structp png_ptr));
   1559 #endif
   1560 
   1561 #if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
   1562 /* Expand the grayscale to 24-bit RGB if necessary. */
   1563 extern PNG_EXPORT(void,png_set_gray_to_rgb) PNGARG((png_structp png_ptr));
   1564 #endif
   1565 
   1566 #if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
   1567 /* Reduce RGB to grayscale. */
   1568 #ifdef PNG_FLOATING_POINT_SUPPORTED
   1569 extern PNG_EXPORT(void,png_set_rgb_to_gray) PNGARG((png_structp png_ptr,
   1570    int error_action, double red, double green ));
   1571 #endif
   1572 extern PNG_EXPORT(void,png_set_rgb_to_gray_fixed) PNGARG((png_structp png_ptr,
   1573    int error_action, png_fixed_point red, png_fixed_point green ));
   1574 extern PNG_EXPORT(png_byte,png_get_rgb_to_gray_status) PNGARG((png_structp
   1575    png_ptr));
   1576 #endif
   1577 
   1578 extern PNG_EXPORT(void,png_build_grayscale_palette) PNGARG((int bit_depth,
   1579    png_colorp palette));
   1580 
   1581 #if defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
   1582 extern PNG_EXPORT(void,png_set_strip_alpha) PNGARG((png_structp png_ptr));
   1583 #endif
   1584 
   1585 #if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
   1586     defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
   1587 extern PNG_EXPORT(void,png_set_swap_alpha) PNGARG((png_structp png_ptr));
   1588 #endif
   1589 
   1590 #if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \
   1591     defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
   1592 extern PNG_EXPORT(void,png_set_invert_alpha) PNGARG((png_structp png_ptr));
   1593 #endif
   1594 
   1595 #if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
   1596 /* Add a filler byte to 8-bit Gray or 24-bit RGB images. */
   1597 extern PNG_EXPORT(void,png_set_filler) PNGARG((png_structp png_ptr,
   1598    png_uint_32 filler, int flags));
   1599 /* The values of the PNG_FILLER_ defines should NOT be changed */
   1600 #define PNG_FILLER_BEFORE 0
   1601 #define PNG_FILLER_AFTER 1
   1602 /* Add an alpha byte to 8-bit Gray or 24-bit RGB images. */
   1603 #if !defined(PNG_1_0_X)
   1604 extern PNG_EXPORT(void,png_set_add_alpha) PNGARG((png_structp png_ptr,
   1605    png_uint_32 filler, int flags));
   1606 #endif
   1607 #endif /* PNG_READ_FILLER_SUPPORTED || PNG_WRITE_FILLER_SUPPORTED */
   1608 
   1609 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
   1610 /* Swap bytes in 16-bit depth files. */
   1611 extern PNG_EXPORT(void,png_set_swap) PNGARG((png_structp png_ptr));
   1612 #endif
   1613 
   1614 #if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
   1615 /* Use 1 byte per pixel in 1, 2, or 4-bit depth files. */
   1616 extern PNG_EXPORT(void,png_set_packing) PNGARG((png_structp png_ptr));
   1617 #endif
   1618 
   1619 #if defined(PNG_READ_PACKSWAP_SUPPORTED) || defined(PNG_WRITE_PACKSWAP_SUPPORTED)
   1620 /* Swap packing order of pixels in bytes. */
   1621 extern PNG_EXPORT(void,png_set_packswap) PNGARG((png_structp png_ptr));
   1622 #endif
   1623 
   1624 #if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
   1625 /* Converts files to legal bit depths. */
   1626 extern PNG_EXPORT(void,png_set_shift) PNGARG((png_structp png_ptr,
   1627    png_color_8p true_bits));
   1628 #endif
   1629 
   1630 #if defined(PNG_READ_INTERLACING_SUPPORTED) || \
   1631     defined(PNG_WRITE_INTERLACING_SUPPORTED)
   1632 /* Have the code handle the interlacing.  Returns the number of passes. */
   1633 extern PNG_EXPORT(int,png_set_interlace_handling) PNGARG((png_structp png_ptr));
   1634 #endif
   1635 
   1636 #if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
   1637 /* Invert monochrome files */
   1638 extern PNG_EXPORT(void,png_set_invert_mono) PNGARG((png_structp png_ptr));
   1639 #endif
   1640 
   1641 #if defined(PNG_READ_BACKGROUND_SUPPORTED)
   1642 /* Handle alpha and tRNS by replacing with a background color. */
   1643 #ifdef PNG_FLOATING_POINT_SUPPORTED
   1644 extern PNG_EXPORT(void,png_set_background) PNGARG((png_structp png_ptr,
   1645    png_color_16p background_color, int background_gamma_code,
   1646    int need_expand, double background_gamma));
   1647 #endif
   1648 #define PNG_BACKGROUND_GAMMA_UNKNOWN 0
   1649 #define PNG_BACKGROUND_GAMMA_SCREEN  1
   1650 #define PNG_BACKGROUND_GAMMA_FILE    2
   1651 #define PNG_BACKGROUND_GAMMA_UNIQUE  3
   1652 #endif
   1653 
   1654 #if defined(PNG_READ_16_TO_8_SUPPORTED)
   1655 /* strip the second byte of information from a 16-bit depth file. */
   1656 extern PNG_EXPORT(void,png_set_strip_16) PNGARG((png_structp png_ptr));
   1657 #endif
   1658 
   1659 #if defined(PNG_READ_DITHER_SUPPORTED)
   1660 /* Turn on dithering, and reduce the palette to the number of colors available. */
   1661 extern PNG_EXPORT(void,png_set_dither) PNGARG((png_structp png_ptr,
   1662    png_colorp palette, int num_palette, int maximum_colors,
   1663    png_uint_16p histogram, int full_dither));
   1664 #endif
   1665 
   1666 #if defined(PNG_READ_GAMMA_SUPPORTED)
   1667 /* Handle gamma correction. Screen_gamma=(display_exponent) */
   1668 #ifdef PNG_FLOATING_POINT_SUPPORTED
   1669 extern PNG_EXPORT(void,png_set_gamma) PNGARG((png_structp png_ptr,
   1670    double screen_gamma, double default_file_gamma));
   1671 #endif
   1672 #endif
   1673 
   1674 #if defined(PNG_1_0_X) || defined (PNG_1_2_X)
   1675 #if defined(PNG_READ_EMPTY_PLTE_SUPPORTED) || \
   1676     defined(PNG_WRITE_EMPTY_PLTE_SUPPORTED)
   1677 /* Permit or disallow empty PLTE (0: not permitted, 1: permitted) */
   1678 /* Deprecated and will be removed.  Use png_permit_mng_features() instead. */
   1679 extern PNG_EXPORT(void,png_permit_empty_plte) PNGARG((png_structp png_ptr,
   1680    int empty_plte_permitted));
   1681 #endif
   1682 #endif
   1683 
   1684 #if defined(PNG_WRITE_FLUSH_SUPPORTED)
   1685 /* Set how many lines between output flushes - 0 for no flushing */
   1686 extern PNG_EXPORT(void,png_set_flush) PNGARG((png_structp png_ptr, int nrows));
   1687 /* Flush the current PNG output buffer */
   1688 extern PNG_EXPORT(void,png_write_flush) PNGARG((png_structp png_ptr));
   1689 #endif
   1690 
   1691 /* optional update palette with requested transformations */
   1692 extern PNG_EXPORT(void,png_start_read_image) PNGARG((png_structp png_ptr));
   1693 
   1694 /* optional call to update the users info structure */
   1695 extern PNG_EXPORT(void,png_read_update_info) PNGARG((png_structp png_ptr,
   1696    png_infop info_ptr));
   1697 
   1698 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
   1699 /* read one or more rows of image data. */
   1700 extern PNG_EXPORT(void,png_read_rows) PNGARG((png_structp png_ptr,
   1701    png_bytepp row, png_bytepp display_row, png_uint_32 num_rows));
   1702 #endif
   1703 
   1704 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
   1705 /* read a row of data. */
   1706 extern PNG_EXPORT(void,png_read_row) PNGARG((png_structp png_ptr,
   1707    png_bytep row,
   1708    png_bytep display_row));
   1709 #endif
   1710 
   1711 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
   1712 /* read the whole image into memory at once. */
   1713 extern PNG_EXPORT(void,png_read_image) PNGARG((png_structp png_ptr,
   1714    png_bytepp image));
   1715 #endif
   1716 
   1717 /* write a row of image data */
   1718 extern PNG_EXPORT(void,png_write_row) PNGARG((png_structp png_ptr,
   1719    png_bytep row));
   1720 
   1721 /* write a few rows of image data */
   1722 extern PNG_EXPORT(void,png_write_rows) PNGARG((png_structp png_ptr,
   1723    png_bytepp row, png_uint_32 num_rows));
   1724 
   1725 /* write the image data */
   1726 extern PNG_EXPORT(void,png_write_image) PNGARG((png_structp png_ptr,
   1727    png_bytepp image));
   1728 
   1729 /* writes the end of the PNG file. */
   1730 extern PNG_EXPORT(void,png_write_end) PNGARG((png_structp png_ptr,
   1731    png_infop info_ptr));
   1732 
   1733 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
   1734 /* read the end of the PNG file. */
   1735 extern PNG_EXPORT(void,png_read_end) PNGARG((png_structp png_ptr,
   1736    png_infop info_ptr));
   1737 #endif
   1738 
   1739 /* free any memory associated with the png_info_struct */
   1740 extern PNG_EXPORT(void,png_destroy_info_struct) PNGARG((png_structp png_ptr,
   1741    png_infopp info_ptr_ptr));
   1742 
   1743 /* free any memory associated with the png_struct and the png_info_structs */
   1744 extern PNG_EXPORT(void,png_destroy_read_struct) PNGARG((png_structpp
   1745    png_ptr_ptr, png_infopp info_ptr_ptr, png_infopp end_info_ptr_ptr));
   1746 
   1747 /* free all memory used by the read (old method - NOT DLL EXPORTED) */
   1748 extern void png_read_destroy PNGARG((png_structp png_ptr, png_infop info_ptr,
   1749    png_infop end_info_ptr));
   1750 
   1751 /* free any memory associated with the png_struct and the png_info_structs */
   1752 extern PNG_EXPORT(void,png_destroy_write_struct)
   1753    PNGARG((png_structpp png_ptr_ptr, png_infopp info_ptr_ptr));
   1754 
   1755 /* free any memory used in png_ptr struct (old method - NOT DLL EXPORTED) */
   1756 extern void png_write_destroy PNGARG((png_structp png_ptr));
   1757 
   1758 /* set the libpng method of handling chunk CRC errors */
   1759 extern PNG_EXPORT(void,png_set_crc_action) PNGARG((png_structp png_ptr,
   1760    int crit_action, int ancil_action));
   1761 
   1762 /* Values for png_set_crc_action() to say how to handle CRC errors in
   1763  * ancillary and critical chunks, and whether to use the data contained
   1764  * therein.  Note that it is impossible to "discard" data in a critical
   1765  * chunk.  For versions prior to 0.90, the action was always error/quit,
   1766  * whereas in version 0.90 and later, the action for CRC errors in ancillary
   1767  * chunks is warn/discard.  These values should NOT be changed.
   1768  *
   1769  *      value                       action:critical     action:ancillary
   1770  */
   1771 #define PNG_CRC_DEFAULT       0  /* error/quit          warn/discard data */
   1772 #define PNG_CRC_ERROR_QUIT    1  /* error/quit          error/quit        */
   1773 #define PNG_CRC_WARN_DISCARD  2  /* (INVALID)           warn/discard data */
   1774 #define PNG_CRC_WARN_USE      3  /* warn/use data       warn/use data     */
   1775 #define PNG_CRC_QUIET_USE     4  /* quiet/use data      quiet/use data    */
   1776 #define PNG_CRC_NO_CHANGE     5  /* use current value   use current value */
   1777 
   1778 /* These functions give the user control over the scan-line filtering in
   1779  * libpng and the compression methods used by zlib.  These functions are
   1780  * mainly useful for testing, as the defaults should work with most users.
   1781  * Those users who are tight on memory or want faster performance at the
   1782  * expense of compression can modify them.  See the compression library
   1783  * header file (zlib.h) for an explination of the compression functions.
   1784  */
   1785 
   1786 /* set the filtering method(s) used by libpng.  Currently, the only valid
   1787  * value for "method" is 0.
   1788  */
   1789 extern PNG_EXPORT(void,png_set_filter) PNGARG((png_structp png_ptr, int method,
   1790    int filters));
   1791 
   1792 /* Flags for png_set_filter() to say which filters to use.  The flags
   1793  * are chosen so that they don't conflict with real filter types
   1794  * below, in case they are supplied instead of the #defined constants.
   1795  * These values should NOT be changed.
   1796  */
   1797 #define PNG_NO_FILTERS     0x00
   1798 #define PNG_FILTER_NONE    0x08
   1799 #define PNG_FILTER_SUB     0x10
   1800 #define PNG_FILTER_UP      0x20
   1801 #define PNG_FILTER_AVG     0x40
   1802 #define PNG_FILTER_PAETH   0x80
   1803 #define PNG_ALL_FILTERS (PNG_FILTER_NONE | PNG_FILTER_SUB | PNG_FILTER_UP | \
   1804                          PNG_FILTER_AVG | PNG_FILTER_PAETH)
   1805 
   1806 /* Filter values (not flags) - used in pngwrite.c, pngwutil.c for now.
   1807  * These defines should NOT be changed.
   1808  */
   1809 #define PNG_FILTER_VALUE_NONE  0
   1810 #define PNG_FILTER_VALUE_SUB   1
   1811 #define PNG_FILTER_VALUE_UP    2
   1812 #define PNG_FILTER_VALUE_AVG   3
   1813 #define PNG_FILTER_VALUE_PAETH 4
   1814 #define PNG_FILTER_VALUE_LAST  5
   1815 
   1816 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED) /* EXPERIMENTAL */
   1817 /* The "heuristic_method" is given by one of the PNG_FILTER_HEURISTIC_
   1818  * defines, either the default (minimum-sum-of-absolute-differences), or
   1819  * the experimental method (weighted-minimum-sum-of-absolute-differences).
   1820  *
   1821  * Weights are factors >= 1.0, indicating how important it is to keep the
   1822  * filter type consistent between rows.  Larger numbers mean the current
   1823  * filter is that many times as likely to be the same as the "num_weights"
   1824  * previous filters.  This is cumulative for each previous row with a weight.
   1825  * There needs to be "num_weights" values in "filter_weights", or it can be
   1826  * NULL if the weights aren't being specified.  Weights have no influence on
   1827  * the selection of the first row filter.  Well chosen weights can (in theory)
   1828  * improve the compression for a given image.
   1829  *
   1830  * Costs are factors >= 1.0 indicating the relative decoding costs of a
   1831  * filter type.  Higher costs indicate more decoding expense, and are
   1832  * therefore less likely to be selected over a filter with lower computational
   1833  * costs.  There needs to be a value in "filter_costs" for each valid filter
   1834  * type (given by PNG_FILTER_VALUE_LAST), or it can be NULL if you aren't
   1835  * setting the costs.  Costs try to improve the speed of decompression without
   1836  * unduly increasing the compressed image size.
   1837  *
   1838  * A negative weight or cost indicates the default value is to be used, and
   1839  * values in the range [0.0, 1.0) indicate the value is to remain unchanged.
   1840  * The default values for both weights and costs are currently 1.0, but may
   1841  * change if good general weighting/cost heuristics can be found.  If both
   1842  * the weights and costs are set to 1.0, this degenerates the WEIGHTED method
   1843  * to the UNWEIGHTED method, but with added encoding time/computation.
   1844  */
   1845 #ifdef PNG_FLOATING_POINT_SUPPORTED
   1846 extern PNG_EXPORT(void,png_set_filter_heuristics) PNGARG((png_structp png_ptr,
   1847    int heuristic_method, int num_weights, png_doublep filter_weights,
   1848    png_doublep filter_costs));
   1849 #endif
   1850 #endif /*  PNG_WRITE_WEIGHTED_FILTER_SUPPORTED */
   1851 
   1852 /* Heuristic used for row filter selection.  These defines should NOT be
   1853  * changed.
   1854  */
   1855 #define PNG_FILTER_HEURISTIC_DEFAULT    0  /* Currently "UNWEIGHTED" */
   1856 #define PNG_FILTER_HEURISTIC_UNWEIGHTED 1  /* Used by libpng < 0.95 */
   1857 #define PNG_FILTER_HEURISTIC_WEIGHTED   2  /* Experimental feature */
   1858 #define PNG_FILTER_HEURISTIC_LAST       3  /* Not a valid value */
   1859 
   1860 /* Set the library compression level.  Currently, valid values range from
   1861  * 0 - 9, corresponding directly to the zlib compression levels 0 - 9
   1862  * (0 - no compression, 9 - "maximal" compression).  Note that tests have
   1863  * shown that zlib compression levels 3-6 usually perform as well as level 9
   1864  * for PNG images, and do considerably fewer caclulations.  In the future,
   1865  * these values may not correspond directly to the zlib compression levels.
   1866  */
   1867 extern PNG_EXPORT(void,png_set_compression_level) PNGARG((png_structp png_ptr,
   1868    int level));
   1869 
   1870 extern PNG_EXPORT(void,png_set_compression_mem_level)
   1871    PNGARG((png_structp png_ptr, int mem_level));
   1872 
   1873 extern PNG_EXPORT(void,png_set_compression_strategy)
   1874    PNGARG((png_structp png_ptr, int strategy));
   1875 
   1876 extern PNG_EXPORT(void,png_set_compression_window_bits)
   1877    PNGARG((png_structp png_ptr, int window_bits));
   1878 
   1879 extern PNG_EXPORT(void,png_set_compression_method) PNGARG((png_structp png_ptr,
   1880    int method));
   1881 
   1882 /* These next functions are called for input/output, memory, and error
   1883  * handling.  They are in the file pngrio.c, pngwio.c, and pngerror.c,
   1884  * and call standard C I/O routines such as fread(), fwrite(), and
   1885  * fprintf().  These functions can be made to use other I/O routines
   1886  * at run time for those applications that need to handle I/O in a
   1887  * different manner by calling png_set_???_fn().  See libpng.txt for
   1888  * more information.
   1889  */
   1890 
   1891 #if !defined(PNG_NO_STDIO)
   1892 /* Initialize the input/output for the PNG file to the default functions. */
   1893 extern PNG_EXPORT(void,png_init_io) PNGARG((png_structp png_ptr, png_FILE_p fp));
   1894 #endif
   1895 
   1896 /* Replace the (error and abort), and warning functions with user
   1897  * supplied functions.  If no messages are to be printed you must still
   1898  * write and use replacement functions. The replacement error_fn should
   1899  * still do a longjmp to the last setjmp location if you are using this
   1900  * method of error handling.  If error_fn or warning_fn is NULL, the
   1901  * default function will be used.
   1902  */
   1903 
   1904 extern PNG_EXPORT(void,png_set_error_fn) PNGARG((png_structp png_ptr,
   1905    png_voidp error_ptr, png_error_ptr error_fn, png_error_ptr warning_fn));
   1906 
   1907 /* Return the user pointer associated with the error functions */
   1908 extern PNG_EXPORT(png_voidp,png_get_error_ptr) PNGARG((png_structp png_ptr));
   1909 
   1910 /* Replace the default data output functions with a user supplied one(s).
   1911  * If buffered output is not used, then output_flush_fn can be set to NULL.
   1912  * If PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile time
   1913  * output_flush_fn will be ignored (and thus can be NULL).
   1914  */
   1915 extern PNG_EXPORT(void,png_set_write_fn) PNGARG((png_structp png_ptr,
   1916    png_voidp io_ptr, png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn));
   1917 
   1918 /* Replace the default data input function with a user supplied one. */
   1919 extern PNG_EXPORT(void,png_set_read_fn) PNGARG((png_structp png_ptr,
   1920    png_voidp io_ptr, png_rw_ptr read_data_fn));
   1921 
   1922 /* Return the user pointer associated with the I/O functions */
   1923 extern PNG_EXPORT(png_voidp,png_get_io_ptr) PNGARG((png_structp png_ptr));
   1924 
   1925 extern PNG_EXPORT(void,png_set_read_status_fn) PNGARG((png_structp png_ptr,
   1926    png_read_status_ptr read_row_fn));
   1927 
   1928 extern PNG_EXPORT(void,png_set_write_status_fn) PNGARG((png_structp png_ptr,
   1929    png_write_status_ptr write_row_fn));
   1930 
   1931 #ifdef PNG_USER_MEM_SUPPORTED
   1932 /* Replace the default memory allocation functions with user supplied one(s). */
   1933 extern PNG_EXPORT(void,png_set_mem_fn) PNGARG((png_structp png_ptr,
   1934    png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn));
   1935 /* Return the user pointer associated with the memory functions */
   1936 extern PNG_EXPORT(png_voidp,png_get_mem_ptr) PNGARG((png_structp png_ptr));
   1937 #endif
   1938 
   1939 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
   1940     defined(PNG_LEGACY_SUPPORTED)
   1941 extern PNG_EXPORT(void,png_set_read_user_transform_fn) PNGARG((png_structp
   1942    png_ptr, png_user_transform_ptr read_user_transform_fn));
   1943 #endif
   1944 
   1945 #if defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) || \
   1946     defined(PNG_LEGACY_SUPPORTED)
   1947 extern PNG_EXPORT(void,png_set_write_user_transform_fn) PNGARG((png_structp
   1948    png_ptr, png_user_transform_ptr write_user_transform_fn));
   1949 #endif
   1950 
   1951 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
   1952     defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) || \
   1953     defined(PNG_LEGACY_SUPPORTED)
   1954 extern PNG_EXPORT(void,png_set_user_transform_info) PNGARG((png_structp
   1955    png_ptr, png_voidp user_transform_ptr, int user_transform_depth,
   1956    int user_transform_channels));
   1957 /* Return the user pointer associated with the user transform functions */
   1958 extern PNG_EXPORT(png_voidp,png_get_user_transform_ptr)
   1959    PNGARG((png_structp png_ptr));
   1960 #endif
   1961 
   1962 #ifdef PNG_USER_CHUNKS_SUPPORTED
   1963 extern PNG_EXPORT(void,png_set_read_user_chunk_fn) PNGARG((png_structp png_ptr,
   1964    png_voidp user_chunk_ptr, png_user_chunk_ptr read_user_chunk_fn));
   1965 extern PNG_EXPORT(png_voidp,png_get_user_chunk_ptr) PNGARG((png_structp
   1966    png_ptr));
   1967 #endif
   1968 
   1969 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
   1970 /* Sets the function callbacks for the push reader, and a pointer to a
   1971  * user-defined structure available to the callback functions.
   1972  */
   1973 extern PNG_EXPORT(void,png_set_progressive_read_fn) PNGARG((png_structp png_ptr,
   1974    png_voidp progressive_ptr,
   1975    png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
   1976    png_progressive_end_ptr end_fn));
   1977 
   1978 /* returns the user pointer associated with the push read functions */
   1979 extern PNG_EXPORT(png_voidp,png_get_progressive_ptr)
   1980    PNGARG((png_structp png_ptr));
   1981 
   1982 /* function to be called when data becomes available */
   1983 extern PNG_EXPORT(void,png_process_data) PNGARG((png_structp png_ptr,
   1984    png_infop info_ptr, png_bytep buffer, png_size_t buffer_size));
   1985 
   1986 /* function that combines rows.  Not very much different than the
   1987  * png_combine_row() call.  Is this even used?????
   1988  */
   1989 extern PNG_EXPORT(void,png_progressive_combine_row) PNGARG((png_structp png_ptr,
   1990    png_bytep old_row, png_bytep new_row));
   1991 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
   1992 
   1993 extern PNG_EXPORT(png_voidp,png_malloc) PNGARG((png_structp png_ptr,
   1994    png_uint_32 size));
   1995 
   1996 #if defined(PNG_1_0_X)
   1997 #  define png_malloc_warn png_malloc
   1998 #else
   1999 /* Added at libpng version 1.2.4 */
   2000 extern PNG_EXPORT(png_voidp,png_malloc_warn) PNGARG((png_structp png_ptr,
   2001    png_uint_32 size));
   2002 #endif
   2003 
   2004 /* frees a pointer allocated by png_malloc() */
   2005 extern PNG_EXPORT(void,png_free) PNGARG((png_structp png_ptr, png_voidp ptr));
   2006 
   2007 #if defined(PNG_1_0_X)
   2008 /* Function to allocate memory for zlib. */
   2009 extern PNG_EXPORT(voidpf,png_zalloc) PNGARG((voidpf png_ptr, uInt items,
   2010    uInt size));
   2011 
   2012 /* Function to free memory for zlib */
   2013 extern PNG_EXPORT(void,png_zfree) PNGARG((voidpf png_ptr, voidpf ptr));
   2014 #endif
   2015 
   2016 /* Free data that was allocated internally */
   2017 extern PNG_EXPORT(void,png_free_data) PNGARG((png_structp png_ptr,
   2018    png_infop info_ptr, png_uint_32 free_me, int num));
   2019 #ifdef PNG_FREE_ME_SUPPORTED
   2020 /* Reassign responsibility for freeing existing data, whether allocated
   2021  * by libpng or by the application */
   2022 extern PNG_EXPORT(void,png_data_freer) PNGARG((png_structp png_ptr,
   2023    png_infop info_ptr, int freer, png_uint_32 mask));
   2024 #endif
   2025 /* assignments for png_data_freer */
   2026 #define PNG_DESTROY_WILL_FREE_DATA 1
   2027 #define PNG_SET_WILL_FREE_DATA 1
   2028 #define PNG_USER_WILL_FREE_DATA 2
   2029 /* Flags for png_ptr->free_me and info_ptr->free_me */
   2030 #define PNG_FREE_HIST 0x0008
   2031 #define PNG_FREE_ICCP 0x0010
   2032 #define PNG_FREE_SPLT 0x0020
   2033 #define PNG_FREE_ROWS 0x0040
   2034 #define PNG_FREE_PCAL 0x0080
   2035 #define PNG_FREE_SCAL 0x0100
   2036 #define PNG_FREE_UNKN 0x0200
   2037 #define PNG_FREE_LIST 0x0400
   2038 #define PNG_FREE_PLTE 0x1000
   2039 #define PNG_FREE_TRNS 0x2000
   2040 #define PNG_FREE_TEXT 0x4000
   2041 #define PNG_FREE_ALL  0x7fff
   2042 #define PNG_FREE_MUL  0x4220 /* PNG_FREE_SPLT|PNG_FREE_TEXT|PNG_FREE_UNKN */
   2043 
   2044 #ifdef PNG_USER_MEM_SUPPORTED
   2045 extern PNG_EXPORT(png_voidp,png_malloc_default) PNGARG((png_structp png_ptr,
   2046    png_uint_32 size));
   2047 extern PNG_EXPORT(void,png_free_default) PNGARG((png_structp png_ptr,
   2048    png_voidp ptr));
   2049 #endif
   2050 
   2051 extern PNG_EXPORT(png_voidp,png_memcpy_check) PNGARG((png_structp png_ptr,
   2052    png_voidp s1, png_voidp s2, png_uint_32 size));
   2053 
   2054 extern PNG_EXPORT(png_voidp,png_memset_check) PNGARG((png_structp png_ptr,
   2055    png_voidp s1, int value, png_uint_32 size));
   2056 
   2057 #if defined(USE_FAR_KEYWORD)  /* memory model conversion function */
   2058 extern void *png_far_to_near PNGARG((png_structp png_ptr,png_voidp ptr,
   2059    int check));
   2060 #endif /* USE_FAR_KEYWORD */
   2061 
   2062 /* Fatal error in PNG image of libpng - can't continue */
   2063 extern PNG_EXPORT(void,png_error) PNGARG((png_structp png_ptr,
   2064    png_const_charp error_message));
   2065 
   2066 /* The same, but the chunk name is prepended to the error string. */
   2067 extern PNG_EXPORT(void,png_chunk_error) PNGARG((png_structp png_ptr,
   2068    png_const_charp error_message));
   2069 
   2070 #ifndef PNG_NO_WARNINGS
   2071 /* Non-fatal error in libpng.  Can continue, but may have a problem. */
   2072 extern PNG_EXPORT(void,png_warning) PNGARG((png_structp png_ptr,
   2073    png_const_charp warning_message));
   2074 
   2075 #ifdef PNG_READ_SUPPORTED
   2076 /* Non-fatal error in libpng, chunk name is prepended to message. */
   2077 extern PNG_EXPORT(void,png_chunk_warning) PNGARG((png_structp png_ptr,
   2078    png_const_charp warning_message));
   2079 #endif /* PNG_READ_SUPPORTED */
   2080 #endif /* PNG_NO_WARNINGS */
   2081 
   2082 /* The png_set_<chunk> functions are for storing values in the png_info_struct.
   2083  * Similarly, the png_get_<chunk> calls are used to read values from the
   2084  * png_info_struct, either storing the parameters in the passed variables, or
   2085  * setting pointers into the png_info_struct where the data is stored.  The
   2086  * png_get_<chunk> functions return a non-zero value if the data was available
   2087  * in info_ptr, or return zero and do not change any of the parameters if the
   2088  * data was not available.
   2089  *
   2090  * These functions should be used instead of directly accessing png_info
   2091  * to avoid problems with future changes in the size and internal layout of
   2092  * png_info_struct.
   2093  */
   2094 /* Returns "flag" if chunk data is valid in info_ptr. */
   2095 extern PNG_EXPORT(png_uint_32,png_get_valid) PNGARG((png_structp png_ptr,
   2096 png_infop info_ptr, png_uint_32 flag));
   2097 
   2098 /* Returns number of bytes needed to hold a transformed row. */
   2099 extern PNG_EXPORT(png_uint_32,png_get_rowbytes) PNGARG((png_structp png_ptr,
   2100 png_infop info_ptr));
   2101 
   2102 #if defined(PNG_INFO_IMAGE_SUPPORTED)
   2103 /* Returns row_pointers, which is an array of pointers to scanlines that was
   2104 returned from png_read_png(). */
   2105 extern PNG_EXPORT(png_bytepp,png_get_rows) PNGARG((png_structp png_ptr,
   2106 png_infop info_ptr));
   2107 /* Set row_pointers, which is an array of pointers to scanlines for use
   2108 by png_write_png(). */
   2109 extern PNG_EXPORT(void,png_set_rows) PNGARG((png_structp png_ptr,
   2110    png_infop info_ptr, png_bytepp row_pointers));
   2111 #endif
   2112 
   2113 /* Returns number of color channels in image. */
   2114 extern PNG_EXPORT(png_byte,png_get_channels) PNGARG((png_structp png_ptr,
   2115 png_infop info_ptr));
   2116 
   2117 #ifdef PNG_EASY_ACCESS_SUPPORTED
   2118 /* Returns image width in pixels. */
   2119 extern PNG_EXPORT(png_uint_32, png_get_image_width) PNGARG((png_structp
   2120 png_ptr, png_infop info_ptr));
   2121 
   2122 /* Returns image height in pixels. */
   2123 extern PNG_EXPORT(png_uint_32, png_get_image_height) PNGARG((png_structp
   2124 png_ptr, png_infop info_ptr));
   2125 
   2126 /* Returns image bit_depth. */
   2127 extern PNG_EXPORT(png_byte, png_get_bit_depth) PNGARG((png_structp
   2128 png_ptr, png_infop info_ptr));
   2129 
   2130 /* Returns image color_type. */
   2131 extern PNG_EXPORT(png_byte, png_get_color_type) PNGARG((png_structp
   2132 png_ptr, png_infop info_ptr));
   2133 
   2134 /* Returns image filter_type. */
   2135 extern PNG_EXPORT(png_byte, png_get_filter_type) PNGARG((png_structp
   2136 png_ptr, png_infop info_ptr));
   2137 
   2138 /* Returns image interlace_type. */
   2139 extern PNG_EXPORT(png_byte, png_get_interlace_type) PNGARG((png_structp
   2140 png_ptr, png_infop info_ptr));
   2141 
   2142 /* Returns image compression_type. */
   2143 extern PNG_EXPORT(png_byte, png_get_compression_type) PNGARG((png_structp
   2144 png_ptr, png_infop info_ptr));
   2145 
   2146 /* Returns image resolution in pixels per meter, from pHYs chunk data. */
   2147 extern PNG_EXPORT(png_uint_32, png_get_pixels_per_meter) PNGARG((png_structp
   2148 png_ptr, png_infop info_ptr));
   2149 extern PNG_EXPORT(png_uint_32, png_get_x_pixels_per_meter) PNGARG((png_structp
   2150 png_ptr, png_infop info_ptr));
   2151 extern PNG_EXPORT(png_uint_32, png_get_y_pixels_per_meter) PNGARG((png_structp
   2152 png_ptr, png_infop info_ptr));
   2153 
   2154 /* Returns pixel aspect ratio, computed from pHYs chunk data.  */
   2155 #ifdef PNG_FLOATING_POINT_SUPPORTED
   2156 extern PNG_EXPORT(float, png_get_pixel_aspect_ratio) PNGARG((png_structp
   2157 png_ptr, png_infop info_ptr));
   2158 #endif
   2159 
   2160 /* Returns image x, y offset in pixels or microns, from oFFs chunk data. */
   2161 extern PNG_EXPORT(png_int_32, png_get_x_offset_pixels) PNGARG((png_structp
   2162 png_ptr, png_infop info_ptr));
   2163 extern PNG_EXPORT(png_int_32, png_get_y_offset_pixels) PNGARG((png_structp
   2164 png_ptr, png_infop info_ptr));
   2165 extern PNG_EXPORT(png_int_32, png_get_x_offset_microns) PNGARG((png_structp
   2166 png_ptr, png_infop info_ptr));
   2167 extern PNG_EXPORT(png_int_32, png_get_y_offset_microns) PNGARG((png_structp
   2168 png_ptr, png_infop info_ptr));
   2169 
   2170 #endif /* PNG_EASY_ACCESS_SUPPORTED */
   2171 
   2172 /* Returns pointer to signature string read from PNG header */
   2173 extern PNG_EXPORT(png_bytep,png_get_signature) PNGARG((png_structp png_ptr,
   2174 png_infop info_ptr));
   2175 
   2176 #if defined(PNG_bKGD_SUPPORTED)
   2177 extern PNG_EXPORT(png_uint_32,png_get_bKGD) PNGARG((png_structp png_ptr,
   2178    png_infop info_ptr, png_color_16p *background));
   2179 #endif
   2180 
   2181 #if defined(PNG_bKGD_SUPPORTED)
   2182 extern PNG_EXPORT(void,png_set_bKGD) PNGARG((png_structp png_ptr,
   2183    png_infop info_ptr, png_color_16p background));
   2184 #endif
   2185 
   2186 #if defined(PNG_cHRM_SUPPORTED)
   2187 #ifdef PNG_FLOATING_POINT_SUPPORTED
   2188 extern PNG_EXPORT(png_uint_32,png_get_cHRM) PNGARG((png_structp png_ptr,
   2189    png_infop info_ptr, double *white_x, double *white_y, double *red_x,
   2190    double *red_y, double *green_x, double *green_y, double *blue_x,
   2191    double *blue_y));
   2192 #endif
   2193 #ifdef PNG_FIXED_POINT_SUPPORTED
   2194 extern PNG_EXPORT(png_uint_32,png_get_cHRM_fixed) PNGARG((png_structp png_ptr,
   2195    png_infop info_ptr, png_fixed_point *int_white_x, png_fixed_point
   2196    *int_white_y, png_fixed_point *int_red_x, png_fixed_point *int_red_y,
   2197    png_fixed_point *int_green_x, png_fixed_point *int_green_y, png_fixed_point
   2198    *int_blue_x, png_fixed_point *int_blue_y));
   2199 #endif
   2200 #endif
   2201 
   2202 #if defined(PNG_cHRM_SUPPORTED)
   2203 #ifdef PNG_FLOATING_POINT_SUPPORTED
   2204 extern PNG_EXPORT(void,png_set_cHRM) PNGARG((png_structp png_ptr,
   2205    png_infop info_ptr, double white_x, double white_y, double red_x,
   2206    double red_y, double green_x, double green_y, double blue_x, double blue_y));
   2207 #endif
   2208 #ifdef PNG_FIXED_POINT_SUPPORTED
   2209 extern PNG_EXPORT(void,png_set_cHRM_fixed) PNGARG((png_structp png_ptr,
   2210    png_infop info_ptr, png_fixed_point int_white_x, png_fixed_point int_white_y,
   2211    png_fixed_point int_red_x, png_fixed_point int_red_y, png_fixed_point
   2212    int_green_x, png_fixed_point int_green_y, png_fixed_point int_blue_x,
   2213    png_fixed_point int_blue_y));
   2214 #endif
   2215 #endif
   2216 
   2217 #if defined(PNG_gAMA_SUPPORTED)
   2218 #ifdef PNG_FLOATING_POINT_SUPPORTED
   2219 extern PNG_EXPORT(png_uint_32,png_get_gAMA) PNGARG((png_structp png_ptr,
   2220    png_infop info_ptr, double *file_gamma));
   2221 #endif
   2222 extern PNG_EXPORT(png_uint_32,png_get_gAMA_fixed) PNGARG((png_structp png_ptr,
   2223    png_infop info_ptr, png_fixed_point *int_file_gamma));
   2224 #endif
   2225 
   2226 #if defined(PNG_gAMA_SUPPORTED)
   2227 #ifdef PNG_FLOATING_POINT_SUPPORTED
   2228 extern PNG_EXPORT(void,png_set_gAMA) PNGARG((png_structp png_ptr,
   2229    png_infop info_ptr, double file_gamma));
   2230 #endif
   2231 extern PNG_EXPORT(void,png_set_gAMA_fixed) PNGARG((png_structp png_ptr,
   2232    png_infop info_ptr, png_fixed_point int_file_gamma));
   2233 #endif
   2234 
   2235 #if defined(PNG_hIST_SUPPORTED)
   2236 extern PNG_EXPORT(png_uint_32,png_get_hIST) PNGARG((png_structp png_ptr,
   2237    png_infop info_ptr, png_uint_16p *hist));
   2238 #endif
   2239 
   2240 #if defined(PNG_hIST_SUPPORTED)
   2241 extern PNG_EXPORT(void,png_set_hIST) PNGARG((png_structp png_ptr,
   2242    png_infop info_ptr, png_uint_16p hist));
   2243 #endif
   2244 
   2245 extern PNG_EXPORT(png_uint_32,png_get_IHDR) PNGARG((png_structp png_ptr,
   2246    png_infop info_ptr, png_uint_32 *width, png_uint_32 *height,
   2247    int *bit_depth, int *color_type, int *interlace_method,
   2248    int *compression_method, int *filter_method));
   2249 
   2250 extern PNG_EXPORT(void,png_set_IHDR) PNGARG((png_structp png_ptr,
   2251    png_infop info_ptr, png_uint_32 width, png_uint_32 height, int bit_depth,
   2252    int color_type, int interlace_method, int compression_method,
   2253    int filter_method));
   2254 
   2255 #if defined(PNG_oFFs_SUPPORTED)
   2256 extern PNG_EXPORT(png_uint_32,png_get_oFFs) PNGARG((png_structp png_ptr,
   2257    png_infop info_ptr, png_int_32 *offset_x, png_int_32 *offset_y,
   2258    int *unit_type));
   2259 #endif
   2260 
   2261 #if defined(PNG_oFFs_SUPPORTED)
   2262 extern PNG_EXPORT(void,png_set_oFFs) PNGARG((png_structp png_ptr,
   2263    png_infop info_ptr, png_int_32 offset_x, png_int_32 offset_y,
   2264    int unit_type));
   2265 #endif
   2266 
   2267 #if defined(PNG_pCAL_SUPPORTED)
   2268 extern PNG_EXPORT(png_uint_32,png_get_pCAL) PNGARG((png_structp png_ptr,
   2269    png_infop info_ptr, png_charp *purpose, png_int_32 *X0, png_int_32 *X1,
   2270    int *type, int *nparams, png_charp *units, png_charpp *params));
   2271 #endif
   2272 
   2273 #if defined(PNG_pCAL_SUPPORTED)
   2274 extern PNG_EXPORT(void,png_set_pCAL) PNGARG((png_structp png_ptr,
   2275    png_infop info_ptr, png_charp purpose, png_int_32 X0, png_int_32 X1,
   2276    int type, int nparams, png_charp units, png_charpp params));
   2277 #endif
   2278 
   2279 #if defined(PNG_pHYs_SUPPORTED)
   2280 extern PNG_EXPORT(png_uint_32,png_get_pHYs) PNGARG((png_structp png_ptr,
   2281    png_infop info_ptr, png_uint_32 *res_x, png_uint_32 *res_y, int *unit_type));
   2282 #endif
   2283 
   2284 #if defined(PNG_pHYs_SUPPORTED)
   2285 extern PNG_EXPORT(void,png_set_pHYs) PNGARG((png_structp png_ptr,
   2286    png_infop info_ptr, png_uint_32 res_x, png_uint_32 res_y, int unit_type));
   2287 #endif
   2288 
   2289 extern PNG_EXPORT(png_uint_32,png_get_PLTE) PNGARG((png_structp png_ptr,
   2290    png_infop info_ptr, png_colorp *palette, int *num_palette));
   2291 
   2292 extern PNG_EXPORT(void,png_set_PLTE) PNGARG((png_structp png_ptr,
   2293    png_infop info_ptr, png_colorp palette, int num_palette));
   2294 
   2295 #if defined(PNG_sBIT_SUPPORTED)
   2296 extern PNG_EXPORT(png_uint_32,png_get_sBIT) PNGARG((png_structp png_ptr,
   2297    png_infop info_ptr, png_color_8p *sig_bit));
   2298 #endif
   2299 
   2300 #if defined(PNG_sBIT_SUPPORTED)
   2301 extern PNG_EXPORT(void,png_set_sBIT) PNGARG((png_structp png_ptr,
   2302    png_infop info_ptr, png_color_8p sig_bit));
   2303 #endif
   2304 
   2305 #if defined(PNG_sRGB_SUPPORTED)
   2306 extern PNG_EXPORT(png_uint_32,png_get_sRGB) PNGARG((png_structp png_ptr,
   2307    png_infop info_ptr, int *intent));
   2308 #endif
   2309 
   2310 #if defined(PNG_sRGB_SUPPORTED)
   2311 extern PNG_EXPORT(void,png_set_sRGB) PNGARG((png_structp png_ptr,
   2312    png_infop info_ptr, int intent));
   2313 extern PNG_EXPORT(void,png_set_sRGB_gAMA_and_cHRM) PNGARG((png_structp png_ptr,
   2314    png_infop info_ptr, int intent));
   2315 #endif
   2316 
   2317 #if defined(PNG_iCCP_SUPPORTED)
   2318 extern PNG_EXPORT(png_uint_32,png_get_iCCP) PNGARG((png_structp png_ptr,
   2319    png_infop info_ptr, png_charpp name, int *compression_type,
   2320    png_charpp profile, png_uint_32 *proflen));
   2321    /* Note to maintainer: profile should be png_bytepp */
   2322 #endif
   2323 
   2324 #if defined(PNG_iCCP_SUPPORTED)
   2325 extern PNG_EXPORT(void,png_set_iCCP) PNGARG((png_structp png_ptr,
   2326    png_infop info_ptr, png_charp name, int compression_type,
   2327    png_charp profile, png_uint_32 proflen));
   2328    /* Note to maintainer: profile should be png_bytep */
   2329 #endif
   2330 
   2331 #if defined(PNG_sPLT_SUPPORTED)
   2332 extern PNG_EXPORT(png_uint_32,png_get_sPLT) PNGARG((png_structp png_ptr,
   2333    png_infop info_ptr, png_sPLT_tpp entries));
   2334 #endif
   2335 
   2336 #if defined(PNG_sPLT_SUPPORTED)
   2337 extern PNG_EXPORT(void,png_set_sPLT) PNGARG((png_structp png_ptr,
   2338    png_infop info_ptr, png_sPLT_tp entries, int nentries));
   2339 #endif
   2340 
   2341 #if defined(PNG_TEXT_SUPPORTED)
   2342 /* png_get_text also returns the number of text chunks in *num_text */
   2343 extern PNG_EXPORT(png_uint_32,png_get_text) PNGARG((png_structp png_ptr,
   2344    png_infop info_ptr, png_textp *text_ptr, int *num_text));
   2345 #endif
   2346 
   2347 /*
   2348  *  Note while png_set_text() will accept a structure whose text,
   2349  *  language, and  translated keywords are NULL pointers, the structure
   2350  *  returned by png_get_text will always contain regular
   2351  *  zero-terminated C strings.  They might be empty strings but
   2352  *  they will never be NULL pointers.
   2353  */
   2354 
   2355 #if defined(PNG_TEXT_SUPPORTED)
   2356 extern PNG_EXPORT(void,png_set_text) PNGARG((png_structp png_ptr,
   2357    png_infop info_ptr, png_textp text_ptr, int num_text));
   2358 #endif
   2359 
   2360 #if defined(PNG_tIME_SUPPORTED)
   2361 extern PNG_EXPORT(png_uint_32,png_get_tIME) PNGARG((png_structp png_ptr,
   2362    png_infop info_ptr, png_timep *mod_time));
   2363 #endif
   2364 
   2365 #if defined(PNG_tIME_SUPPORTED)
   2366 extern PNG_EXPORT(void,png_set_tIME) PNGARG((png_structp png_ptr,
   2367    png_infop info_ptr, png_timep mod_time));
   2368 #endif
   2369 
   2370 #if defined(PNG_tRNS_SUPPORTED)
   2371 extern PNG_EXPORT(png_uint_32,png_get_tRNS) PNGARG((png_structp png_ptr,
   2372    png_infop info_ptr, png_bytep *trans, int *num_trans,
   2373    png_color_16p *trans_values));
   2374 #endif
   2375 
   2376 #if defined(PNG_tRNS_SUPPORTED)
   2377 extern PNG_EXPORT(void,png_set_tRNS) PNGARG((png_structp png_ptr,
   2378    png_infop info_ptr, png_bytep trans, int num_trans,
   2379    png_color_16p trans_values));
   2380 #endif
   2381 
   2382 #if defined(PNG_tRNS_SUPPORTED)
   2383 #endif
   2384 
   2385 #if defined(PNG_sCAL_SUPPORTED)
   2386 #ifdef PNG_FLOATING_POINT_SUPPORTED
   2387 extern PNG_EXPORT(png_uint_32,png_get_sCAL) PNGARG((png_structp png_ptr,
   2388    png_infop info_ptr, int *unit, double *width, double *height));
   2389 #else
   2390 #ifdef PNG_FIXED_POINT_SUPPORTED
   2391 extern PNG_EXPORT(png_uint_32,png_get_sCAL_s) PNGARG((png_structp png_ptr,
   2392    png_infop info_ptr, int *unit, png_charpp swidth, png_charpp sheight));
   2393 #endif
   2394 #endif
   2395 #endif /* PNG_sCAL_SUPPORTED */
   2396 
   2397 #if defined(PNG_sCAL_SUPPORTED)
   2398 #ifdef PNG_FLOATING_POINT_SUPPORTED
   2399 extern PNG_EXPORT(void,png_set_sCAL) PNGARG((png_structp png_ptr,
   2400    png_infop info_ptr, int unit, double width, double height));
   2401 #else
   2402 #ifdef PNG_FIXED_POINT_SUPPORTED
   2403 extern PNG_EXPORT(void,png_set_sCAL_s) PNGARG((png_structp png_ptr,
   2404    png_infop info_ptr, int unit, png_charp swidth, png_charp sheight));
   2405 #endif
   2406 #endif
   2407 #endif /* PNG_sCAL_SUPPORTED || PNG_WRITE_sCAL_SUPPORTED */
   2408 
   2409 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
   2410 /* provide a list of chunks and how they are to be handled, if the built-in
   2411    handling or default unknown chunk handling is not desired.  Any chunks not
   2412    listed will be handled in the default manner.  The IHDR and IEND chunks
   2413    must not be listed.
   2414       keep = 0: follow default behaviour
   2415            = 1: do not keep
   2416            = 2: keep only if safe-to-copy
   2417            = 3: keep even if unsafe-to-copy
   2418 */
   2419 extern PNG_EXPORT(void, png_set_keep_unknown_chunks) PNGARG((png_structp
   2420    png_ptr, int keep, png_bytep chunk_list, int num_chunks));
   2421 extern PNG_EXPORT(void, png_set_unknown_chunks) PNGARG((png_structp png_ptr,
   2422    png_infop info_ptr, png_unknown_chunkp unknowns, int num_unknowns));
   2423 extern PNG_EXPORT(void, png_set_unknown_chunk_location)
   2424    PNGARG((png_structp png_ptr, png_infop info_ptr, int chunk, int location));
   2425 extern PNG_EXPORT(png_uint_32,png_get_unknown_chunks) PNGARG((png_structp
   2426    png_ptr, png_infop info_ptr, png_unknown_chunkpp entries));
   2427 #endif
   2428 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
   2429 PNG_EXPORT(int,png_handle_as_unknown) PNGARG((png_structp png_ptr, png_bytep
   2430    chunk_name));
   2431 #endif
   2432 
   2433 /* Png_free_data() will turn off the "valid" flag for anything it frees.
   2434    If you need to turn it off for a chunk that your application has freed,
   2435    you can use png_set_invalid(png_ptr, info_ptr, PNG_INFO_CHNK); */
   2436 extern PNG_EXPORT(void, png_set_invalid) PNGARG((png_structp png_ptr,
   2437    png_infop info_ptr, int mask));
   2438 
   2439 #if defined(PNG_INFO_IMAGE_SUPPORTED)
   2440 /* The "params" pointer is currently not used and is for future expansion. */
   2441 extern PNG_EXPORT(void, png_read_png) PNGARG((png_structp png_ptr,
   2442                         png_infop info_ptr,
   2443                         int transforms,
   2444                         png_voidp params));
   2445 extern PNG_EXPORT(void, png_write_png) PNGARG((png_structp png_ptr,
   2446                         png_infop info_ptr,
   2447                         int transforms,
   2448                         png_voidp params));
   2449 #endif
   2450 
   2451 /* Define PNG_DEBUG at compile time for debugging information.  Higher
   2452  * numbers for PNG_DEBUG mean more debugging information.  This has
   2453  * only been added since version 0.95 so it is not implemented throughout
   2454  * libpng yet, but more support will be added as needed.
   2455  */
   2456 #ifdef PNG_DEBUG
   2457 #if (PNG_DEBUG > 0)
   2458 #if !defined(PNG_DEBUG_FILE) && defined(_MSC_VER)
   2459 #include <crtdbg.h>
   2460 #if (PNG_DEBUG > 1)
   2461 #define png_debug(l,m)  _RPT0(_CRT_WARN,m)
   2462 #define png_debug1(l,m,p1)  _RPT1(_CRT_WARN,m,p1)
   2463 #define png_debug2(l,m,p1,p2) _RPT2(_CRT_WARN,m,p1,p2)
   2464 #endif
   2465 #else /* PNG_DEBUG_FILE || !_MSC_VER */
   2466 #ifndef PNG_DEBUG_FILE
   2467 #define PNG_DEBUG_FILE stderr
   2468 #endif /* PNG_DEBUG_FILE */
   2469 #if (PNG_DEBUG > 1)
   2470 #define png_debug(l,m) \
   2471 { \
   2472      int num_tabs=l; \
   2473      fprintf(PNG_DEBUG_FILE,"%s"m,(num_tabs==1 ? "\t" : \
   2474        (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":"")))); \
   2475 }
   2476 #define png_debug1(l,m,p1) \
   2477 { \
   2478      int num_tabs=l; \
   2479      fprintf(PNG_DEBUG_FILE,"%s"m,(num_tabs==1 ? "\t" : \
   2480        (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))),p1); \
   2481 }
   2482 #define png_debug2(l,m,p1,p2) \
   2483 { \
   2484      int num_tabs=l; \
   2485      fprintf(PNG_DEBUG_FILE,"%s"m,(num_tabs==1 ? "\t" : \
   2486        (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))),p1,p2); \
   2487 }
   2488 #endif /* (PNG_DEBUG > 1) */
   2489 #endif /* _MSC_VER */
   2490 #endif /* (PNG_DEBUG > 0) */
   2491 #endif /* PNG_DEBUG */
   2492 #ifndef png_debug
   2493 #define png_debug(l, m)
   2494 #endif
   2495 #ifndef png_debug1
   2496 #define png_debug1(l, m, p1)
   2497 #endif
   2498 #ifndef png_debug2
   2499 #define png_debug2(l, m, p1, p2)
   2500 #endif
   2501 
   2502 extern PNG_EXPORT(png_charp,png_get_copyright) PNGARG((png_structp png_ptr));
   2503 extern PNG_EXPORT(png_charp,png_get_header_ver) PNGARG((png_structp png_ptr));
   2504 extern PNG_EXPORT(png_charp,png_get_header_version) PNGARG((png_structp png_ptr));
   2505 extern PNG_EXPORT(png_charp,png_get_libpng_ver) PNGARG((png_structp png_ptr));
   2506 
   2507 #ifdef PNG_MNG_FEATURES_SUPPORTED
   2508 extern PNG_EXPORT(png_uint_32,png_permit_mng_features) PNGARG((png_structp
   2509    png_ptr, png_uint_32 mng_features_permitted));
   2510 #endif
   2511 
   2512 /* For use in png_set_keep_unknown, added to version 1.2.6 */
   2513 #define PNG_HANDLE_CHUNK_AS_DEFAULT   0
   2514 #define PNG_HANDLE_CHUNK_NEVER        1
   2515 #define PNG_HANDLE_CHUNK_IF_SAFE      2
   2516 #define PNG_HANDLE_CHUNK_ALWAYS       3
   2517 
   2518 /* Added to version 1.2.0 */
   2519 #if defined(PNG_ASSEMBLER_CODE_SUPPORTED)
   2520 #if defined(PNG_MMX_CODE_SUPPORTED)
   2521 #define PNG_ASM_FLAG_MMX_SUPPORT_COMPILED  0x01  /* not user-settable */
   2522 #define PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU    0x02  /* not user-settable */
   2523 #define PNG_ASM_FLAG_MMX_READ_COMBINE_ROW  0x04
   2524 #define PNG_ASM_FLAG_MMX_READ_INTERLACE    0x08
   2525 #define PNG_ASM_FLAG_MMX_READ_FILTER_SUB   0x10
   2526 #define PNG_ASM_FLAG_MMX_READ_FILTER_UP    0x20
   2527 #define PNG_ASM_FLAG_MMX_READ_FILTER_AVG   0x40
   2528 #define PNG_ASM_FLAG_MMX_READ_FILTER_PAETH 0x80
   2529 #define PNG_ASM_FLAGS_INITIALIZED          0x80000000  /* not user-settable */
   2530 
   2531 #define PNG_MMX_READ_FLAGS ( PNG_ASM_FLAG_MMX_READ_COMBINE_ROW  \
   2532                            | PNG_ASM_FLAG_MMX_READ_INTERLACE    \
   2533                            | PNG_ASM_FLAG_MMX_READ_FILTER_SUB   \
   2534                            | PNG_ASM_FLAG_MMX_READ_FILTER_UP    \
   2535                            | PNG_ASM_FLAG_MMX_READ_FILTER_AVG   \
   2536                            | PNG_ASM_FLAG_MMX_READ_FILTER_PAETH )
   2537 #define PNG_MMX_WRITE_FLAGS ( 0 )
   2538 
   2539 #define PNG_MMX_FLAGS ( PNG_ASM_FLAG_MMX_SUPPORT_COMPILED \
   2540                       | PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU   \
   2541                       | PNG_MMX_READ_FLAGS                \
   2542                       | PNG_MMX_WRITE_FLAGS )
   2543 
   2544 #define PNG_SELECT_READ   1
   2545 #define PNG_SELECT_WRITE  2
   2546 #endif /* PNG_MMX_CODE_SUPPORTED */
   2547 
   2548 #if !defined(PNG_1_0_X)
   2549 /* pngget.c */
   2550 extern PNG_EXPORT(png_uint_32,png_get_mmx_flagmask)
   2551    PNGARG((int flag_select, int *compilerID));
   2552 
   2553 /* pngget.c */
   2554 extern PNG_EXPORT(png_uint_32,png_get_asm_flagmask)
   2555    PNGARG((int flag_select));
   2556 
   2557 /* pngget.c */
   2558 extern PNG_EXPORT(png_uint_32,png_get_asm_flags)
   2559    PNGARG((png_structp png_ptr));
   2560 
   2561 /* pngget.c */
   2562 extern PNG_EXPORT(png_byte,png_get_mmx_bitdepth_threshold)
   2563    PNGARG((png_structp png_ptr));
   2564 
   2565 /* pngget.c */
   2566 extern PNG_EXPORT(png_uint_32,png_get_mmx_rowbytes_threshold)
   2567    PNGARG((png_structp png_ptr));
   2568 
   2569 /* pngset.c */
   2570 extern PNG_EXPORT(void,png_set_asm_flags)
   2571    PNGARG((png_structp png_ptr, png_uint_32 asm_flags));
   2572 
   2573 /* pngset.c */
   2574 extern PNG_EXPORT(void,png_set_mmx_thresholds)
   2575    PNGARG((png_structp png_ptr, png_byte mmx_bitdepth_threshold,
   2576    png_uint_32 mmx_rowbytes_threshold));
   2577 
   2578 #endif /* PNG_1_0_X */
   2579 
   2580 #if !defined(PNG_1_0_X)
   2581 /* png.c, pnggccrd.c, or pngvcrd.c */
   2582 extern PNG_EXPORT(int,png_mmx_support) PNGARG((void));
   2583 #endif /* PNG_ASSEMBLER_CODE_SUPPORTED */
   2584 
   2585 /* Strip the prepended error numbers ("#nnn ") from error and warning
   2586  * messages before passing them to the error or warning handler. */
   2587 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
   2588 extern PNG_EXPORT(void,png_set_strip_error_numbers) PNGARG((png_structp
   2589    png_ptr, png_uint_32 strip_mode));
   2590 #endif
   2591 
   2592 #endif /* PNG_1_0_X */
   2593 
   2594 /* Added at libpng-1.2.6 */
   2595 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
   2596 extern PNG_EXPORT(void,png_set_user_limits) PNGARG((png_structp
   2597    png_ptr, png_uint_32 user_width_max, png_uint_32 user_height_max));
   2598 extern PNG_EXPORT(png_uint_32,png_get_user_width_max) PNGARG((png_structp
   2599    png_ptr));
   2600 extern PNG_EXPORT(png_uint_32,png_get_user_height_max) PNGARG((png_structp
   2601    png_ptr));
   2602 #endif
   2603 
   2604 /* Maintainer: Put new public prototypes here ^, in libpng.3, and project defs */
   2605 
   2606 #ifdef PNG_READ_COMPOSITE_NODIV_SUPPORTED
   2607 /* With these routines we avoid an integer divide, which will be slower on
   2608  * most machines.  However, it does take more operations than the corresponding
   2609  * divide method, so it may be slower on a few RISC systems.  There are two
   2610  * shifts (by 8 or 16 bits) and an addition, versus a single integer divide.
   2611  *
   2612  * Note that the rounding factors are NOT supposed to be the same!  128 and
   2613  * 32768 are correct for the NODIV code; 127 and 32767 are correct for the
   2614  * standard method.
   2615  *
   2616  * [Optimized code by Greg Roelofs and Mark Adler...blame us for bugs. :-) ]
   2617  */
   2618 
   2619  /* fg and bg should be in `gamma 1.0' space; alpha is the opacity          */
   2620 
   2621 #  define png_composite(composite, fg, alpha, bg)                            \
   2622      { png_uint_16 temp = (png_uint_16)((png_uint_16)(fg) * (png_uint_16)(alpha) \
   2623                         +        (png_uint_16)(bg)*(png_uint_16)(255 -       \
   2624                         (png_uint_16)(alpha)) + (png_uint_16)128);           \
   2625        (composite) = (png_byte)((temp + (temp >> 8)) >> 8); }
   2626 
   2627 #  define png_composite_16(composite, fg, alpha, bg)                         \
   2628      { png_uint_32 temp = (png_uint_32)((png_uint_32)(fg) * (png_uint_32)(alpha) \
   2629                         + (png_uint_32)(bg)*(png_uint_32)(65535L -           \
   2630                         (png_uint_32)(alpha)) + (png_uint_32)32768L);        \
   2631        (composite) = (png_uint_16)((temp + (temp >> 16)) >> 16); }
   2632 
   2633 #else  /* standard method using integer division */
   2634 
   2635 #  define png_composite(composite, fg, alpha, bg)                            \
   2636      (composite) = (png_byte)(((png_uint_16)(fg) * (png_uint_16)(alpha) +    \
   2637        (png_uint_16)(bg) * (png_uint_16)(255 - (png_uint_16)(alpha)) +       \
   2638        (png_uint_16)127) / 255)
   2639 
   2640 #  define png_composite_16(composite, fg, alpha, bg)                         \
   2641      (composite) = (png_uint_16)(((png_uint_32)(fg) * (png_uint_32)(alpha) + \
   2642        (png_uint_32)(bg)*(png_uint_32)(65535L - (png_uint_32)(alpha)) +      \
   2643        (png_uint_32)32767) / (png_uint_32)65535L)
   2644 
   2645 #endif /* PNG_READ_COMPOSITE_NODIV_SUPPORTED */
   2646 
   2647 /* Inline macros to do direct reads of bytes from the input buffer.  These
   2648  * require that you are using an architecture that uses PNG byte ordering
   2649  * (MSB first) and supports unaligned data storage.  I think that PowerPC
   2650  * in big-endian mode and 680x0 are the only ones that will support this.
   2651  * The x86 line of processors definitely do not.  The png_get_int_32()
   2652  * routine also assumes we are using two's complement format for negative
   2653  * values, which is almost certainly true.
   2654  */
   2655 #if defined(PNG_READ_BIG_ENDIAN_SUPPORTED)
   2656 #  define png_get_uint_32(buf) ( *((png_uint_32p) (buf)))
   2657 #  define png_get_uint_16(buf) ( *((png_uint_16p) (buf)))
   2658 #  define png_get_int_32(buf)  ( *((png_int_32p)  (buf)))
   2659 #else
   2660 extern PNG_EXPORT(png_uint_32,png_get_uint_32) PNGARG((png_bytep buf));
   2661 extern PNG_EXPORT(png_uint_16,png_get_uint_16) PNGARG((png_bytep buf));
   2662 extern PNG_EXPORT(png_int_32,png_get_int_32) PNGARG((png_bytep buf));
   2663 #endif /* !PNG_READ_BIG_ENDIAN_SUPPORTED */
   2664 extern PNG_EXPORT(png_uint_32,png_get_uint_31)
   2665   PNGARG((png_structp png_ptr, png_bytep buf));
   2666 /* No png_get_int_16 -- may be added if there's a real need for it. */
   2667 
   2668 /* Place a 32-bit number into a buffer in PNG byte order (big-endian).
   2669  */
   2670 extern PNG_EXPORT(void,png_save_uint_32)
   2671    PNGARG((png_bytep buf, png_uint_32 i));
   2672 extern PNG_EXPORT(void,png_save_int_32)
   2673    PNGARG((png_bytep buf, png_int_32 i));
   2674 
   2675 /* Place a 16-bit number into a buffer in PNG byte order.
   2676  * The parameter is declared unsigned int, not png_uint_16,
   2677  * just to avoid potential problems on pre-ANSI C compilers.
   2678  */
   2679 extern PNG_EXPORT(void,png_save_uint_16)
   2680    PNGARG((png_bytep buf, unsigned int i));
   2681 /* No png_save_int_16 -- may be added if there's a real need for it. */
   2682 
   2683 /* ************************************************************************* */
   2684 
   2685 /* These next functions are used internally in the code.  They generally
   2686  * shouldn't be used unless you are writing code to add or replace some
   2687  * functionality in libpng.  More information about most functions can
   2688  * be found in the files where the functions are located.
   2689  */
   2690 
   2691 
   2692 /* Various modes of operation, that are visible to applications because
   2693  * they are used for unknown chunk location.
   2694  */
   2695 #define PNG_HAVE_IHDR               0x01
   2696 #define PNG_HAVE_PLTE               0x02
   2697 #define PNG_HAVE_IDAT               0x04
   2698 #define PNG_AFTER_IDAT              0x08 /* Have complete zlib datastream */
   2699 #define PNG_HAVE_IEND               0x10
   2700 
   2701 #if defined(PNG_INTERNAL)
   2702 
   2703 /* More modes of operation.  Note that after an init, mode is set to
   2704  * zero automatically when the structure is created.
   2705  */
   2706 #define PNG_HAVE_gAMA               0x20
   2707 #define PNG_HAVE_cHRM               0x40
   2708 #define PNG_HAVE_sRGB               0x80
   2709 #define PNG_HAVE_CHUNK_HEADER      0x100
   2710 #define PNG_WROTE_tIME             0x200
   2711 #define PNG_WROTE_INFO_BEFORE_PLTE 0x400
   2712 #define PNG_BACKGROUND_IS_GRAY     0x800
   2713 #define PNG_HAVE_PNG_SIGNATURE    0x1000
   2714 #define PNG_HAVE_CHUNK_AFTER_IDAT 0x2000 /* Have another chunk after IDAT */
   2715 
   2716 /* flags for the transformations the PNG library does on the image data */
   2717 #define PNG_BGR                0x0001
   2718 #define PNG_INTERLACE          0x0002
   2719 #define PNG_PACK               0x0004
   2720 #define PNG_SHIFT              0x0008
   2721 #define PNG_SWAP_BYTES         0x0010
   2722 #define PNG_INVERT_MONO        0x0020
   2723 #define PNG_DITHER             0x0040
   2724 #define PNG_BACKGROUND         0x0080
   2725 #define PNG_BACKGROUND_EXPAND  0x0100
   2726                           /*   0x0200 unused */
   2727 #define PNG_16_TO_8            0x0400
   2728 #define PNG_RGBA               0x0800
   2729 #define PNG_EXPAND             0x1000
   2730 #define PNG_GAMMA              0x2000
   2731 #define PNG_GRAY_TO_RGB        0x4000
   2732 #define PNG_FILLER             0x8000L
   2733 #define PNG_PACKSWAP          0x10000L
   2734 #define PNG_SWAP_ALPHA        0x20000L
   2735 #define PNG_STRIP_ALPHA       0x40000L
   2736 #define PNG_INVERT_ALPHA      0x80000L
   2737 #define PNG_USER_TRANSFORM   0x100000L
   2738 #define PNG_RGB_TO_GRAY_ERR  0x200000L
   2739 #define PNG_RGB_TO_GRAY_WARN 0x400000L
   2740 #define PNG_RGB_TO_GRAY      0x600000L  /* two bits, RGB_TO_GRAY_ERR|WARN */
   2741                        /*    0x800000L     Unused */
   2742 #define PNG_ADD_ALPHA       0x1000000L  /* Added to libpng-1.2.7 */
   2743 #define PNG_EXPAND_tRNS     0x2000000L  /* Added to libpng-1.2.9 */
   2744                        /*   0x4000000L  unused */
   2745                        /*   0x8000000L  unused */
   2746                        /*  0x10000000L  unused */
   2747                        /*  0x20000000L  unused */
   2748                        /*  0x40000000L  unused */
   2749 
   2750 /* flags for png_create_struct */
   2751 #define PNG_STRUCT_PNG   0x0001
   2752 #define PNG_STRUCT_INFO  0x0002
   2753 
   2754 /* Scaling factor for filter heuristic weighting calculations */
   2755 #define PNG_WEIGHT_SHIFT 8
   2756 #define PNG_WEIGHT_FACTOR (1<<(PNG_WEIGHT_SHIFT))
   2757 #define PNG_COST_SHIFT 3
   2758 #define PNG_COST_FACTOR (1<<(PNG_COST_SHIFT))
   2759 
   2760 /* flags for the png_ptr->flags rather than declaring a byte for each one */
   2761 #define PNG_FLAG_ZLIB_CUSTOM_STRATEGY     0x0001
   2762 #define PNG_FLAG_ZLIB_CUSTOM_LEVEL        0x0002
   2763 #define PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL    0x0004
   2764 #define PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS  0x0008
   2765 #define PNG_FLAG_ZLIB_CUSTOM_METHOD       0x0010
   2766 #define PNG_FLAG_ZLIB_FINISHED            0x0020
   2767 #define PNG_FLAG_ROW_INIT                 0x0040
   2768 #define PNG_FLAG_FILLER_AFTER             0x0080
   2769 #define PNG_FLAG_CRC_ANCILLARY_USE        0x0100
   2770 #define PNG_FLAG_CRC_ANCILLARY_NOWARN     0x0200
   2771 #define PNG_FLAG_CRC_CRITICAL_USE         0x0400
   2772 #define PNG_FLAG_CRC_CRITICAL_IGNORE      0x0800
   2773 #define PNG_FLAG_FREE_PLTE                0x1000
   2774 #define PNG_FLAG_FREE_TRNS                0x2000
   2775 #define PNG_FLAG_FREE_HIST                0x4000
   2776 #define PNG_FLAG_KEEP_UNKNOWN_CHUNKS      0x8000L
   2777 #define PNG_FLAG_KEEP_UNSAFE_CHUNKS       0x10000L
   2778 #define PNG_FLAG_LIBRARY_MISMATCH         0x20000L
   2779 #define PNG_FLAG_STRIP_ERROR_NUMBERS      0x40000L
   2780 #define PNG_FLAG_STRIP_ERROR_TEXT         0x80000L
   2781 #define PNG_FLAG_MALLOC_NULL_MEM_OK       0x100000L
   2782 #define PNG_FLAG_ADD_ALPHA                0x200000L  /* Added to libpng-1.2.8 */
   2783 #define PNG_FLAG_STRIP_ALPHA              0x400000L  /* Added to libpng-1.2.8 */
   2784                                   /*      0x800000L  unused */
   2785                                   /*     0x1000000L  unused */
   2786                                   /*     0x2000000L  unused */
   2787                                   /*     0x4000000L  unused */
   2788                                   /*     0x8000000L  unused */
   2789                                   /*    0x10000000L  unused */
   2790                                   /*    0x20000000L  unused */
   2791                                   /*    0x40000000L  unused */
   2792 
   2793 #define PNG_FLAG_CRC_ANCILLARY_MASK (PNG_FLAG_CRC_ANCILLARY_USE | \
   2794                                      PNG_FLAG_CRC_ANCILLARY_NOWARN)
   2795 
   2796 #define PNG_FLAG_CRC_CRITICAL_MASK  (PNG_FLAG_CRC_CRITICAL_USE | \
   2797                                      PNG_FLAG_CRC_CRITICAL_IGNORE)
   2798 
   2799 #define PNG_FLAG_CRC_MASK           (PNG_FLAG_CRC_ANCILLARY_MASK | \
   2800                                      PNG_FLAG_CRC_CRITICAL_MASK)
   2801 
   2802 /* save typing and make code easier to understand */
   2803 
   2804 #define PNG_COLOR_DIST(c1, c2) (abs((int)((c1).red) - (int)((c2).red)) + \
   2805    abs((int)((c1).green) - (int)((c2).green)) + \
   2806    abs((int)((c1).blue) - (int)((c2).blue)))
   2807 
   2808 /* Added to libpng-1.2.6 JB */
   2809 #define PNG_ROWBYTES(pixel_bits, width) \
   2810     ((pixel_bits) >= 8 ? \
   2811     ((width) * (((png_uint_32)(pixel_bits)) >> 3)) : \
   2812     (( ((width) * ((png_uint_32)(pixel_bits))) + 7) >> 3) )
   2813 
   2814 /* PNG_OUT_OF_RANGE returns true if value is outside the range
   2815    ideal-delta..ideal+delta.  Each argument is evaluated twice.
   2816    "ideal" and "delta" should be constants, normally simple
   2817    integers, "value" a variable. Added to libpng-1.2.6 JB */
   2818 #define PNG_OUT_OF_RANGE(value, ideal, delta) \
   2819         ( (value) < (ideal)-(delta) || (value) > (ideal)+(delta) )
   2820 
   2821 /* variables declared in png.c - only it needs to define PNG_NO_EXTERN */
   2822 #if !defined(PNG_NO_EXTERN) || defined(PNG_ALWAYS_EXTERN)
   2823 /* place to hold the signature string for a PNG file. */
   2824 #ifdef PNG_USE_GLOBAL_ARRAYS
   2825    PNG_EXPORT_VAR (PNG_CONST png_byte FARDATA) png_sig[8];
   2826 #else
   2827 #endif
   2828 #endif /* PNG_NO_EXTERN */
   2829 
   2830 /* Constant strings for known chunk types.  If you need to add a chunk,
   2831  * define the name here, and add an invocation of the macro in png.c and
   2832  * wherever it's needed.
   2833  */
   2834 #define PNG_IHDR png_byte png_IHDR[5] = { 73,  72,  68,  82, '\0'}
   2835 #define PNG_IDAT png_byte png_IDAT[5] = { 73,  68,  65,  84, '\0'}
   2836 #define PNG_IEND png_byte png_IEND[5] = { 73,  69,  78,  68, '\0'}
   2837 #define PNG_PLTE png_byte png_PLTE[5] = { 80,  76,  84,  69, '\0'}
   2838 #define PNG_bKGD png_byte png_bKGD[5] = { 98,  75,  71,  68, '\0'}
   2839 #define PNG_cHRM png_byte png_cHRM[5] = { 99,  72,  82,  77, '\0'}
   2840 #define PNG_gAMA png_byte png_gAMA[5] = {103,  65,  77,  65, '\0'}
   2841 #define PNG_hIST png_byte png_hIST[5] = {104,  73,  83,  84, '\0'}
   2842 #define PNG_iCCP png_byte png_iCCP[5] = {105,  67,  67,  80, '\0'}
   2843 #define PNG_iTXt png_byte png_iTXt[5] = {105,  84,  88, 116, '\0'}
   2844 #define PNG_oFFs png_byte png_oFFs[5] = {111,  70,  70, 115, '\0'}
   2845 #define PNG_pCAL png_byte png_pCAL[5] = {112,  67,  65,  76, '\0'}
   2846 #define PNG_sCAL png_byte png_sCAL[5] = {115,  67,  65,  76, '\0'}
   2847 #define PNG_pHYs png_byte png_pHYs[5] = {112,  72,  89, 115, '\0'}
   2848 #define PNG_sBIT png_byte png_sBIT[5] = {115,  66,  73,  84, '\0'}
   2849 #define PNG_sPLT png_byte png_sPLT[5] = {115,  80,  76,  84, '\0'}
   2850 #define PNG_sRGB png_byte png_sRGB[5] = {115,  82,  71,  66, '\0'}
   2851 #define PNG_tEXt png_byte png_tEXt[5] = {116,  69,  88, 116, '\0'}
   2852 #define PNG_tIME png_byte png_tIME[5] = {116,  73,  77,  69, '\0'}
   2853 #define PNG_tRNS png_byte png_tRNS[5] = {116,  82,  78,  83, '\0'}
   2854 #define PNG_zTXt png_byte png_zTXt[5] = {122,  84,  88, 116, '\0'}
   2855 
   2856 #ifdef PNG_USE_GLOBAL_ARRAYS
   2857 PNG_EXPORT_VAR (png_byte FARDATA) png_IHDR[5];
   2858 PNG_EXPORT_VAR (png_byte FARDATA) png_IDAT[5];
   2859 PNG_EXPORT_VAR (png_byte FARDATA) png_IEND[5];
   2860 PNG_EXPORT_VAR (png_byte FARDATA) png_PLTE[5];
   2861 PNG_EXPORT_VAR (png_byte FARDATA) png_bKGD[5];
   2862 PNG_EXPORT_VAR (png_byte FARDATA) png_cHRM[5];
   2863 PNG_EXPORT_VAR (png_byte FARDATA) png_gAMA[5];
   2864 PNG_EXPORT_VAR (png_byte FARDATA) png_hIST[5];
   2865 PNG_EXPORT_VAR (png_byte FARDATA) png_iCCP[5];
   2866 PNG_EXPOR