src/png/pngpriv.h

   1 /* pngpriv.h - private declarations for use inside libpng
   2  *
   3  * For conditions of distribution and use, see copyright notice in png.h
   4  * Copyright (c) 1998-2011 Glenn Randers-Pehrson
   5  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
   6  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
   7  *
   8  * Last changed in libpng 1.5.7 [December 15, 2011]
   9  *
  10  * This code is released under the libpng license.
  11  * For conditions of distribution and use, see the disclaimer
  12  * and license in png.h
  13  */
  14
  15 /* The symbols declared in this file (including the functions declared
  16  * as PNG_EXTERN) are PRIVATE.  They are not part of the libpng public
  17  * interface, and are not recommended for use by regular applications.
  18  * Some of them may become public in the future; others may stay private,
  19  * change in an incompatible way, or even disappear.
  20  * Although the libpng users are not forbidden to include this header,
  21  * they should be well aware of the issues that may arise from doing so.
  22  */
  23
  24 #ifndef PNGPRIV_H
  25 #define PNGPRIV_H
  26
  27 /* Feature Test Macros.  The following are defined here to ensure that correctly
  28  * implemented libraries reveal the APIs libpng needs to build and hide those
  29  * that are not needed and potentially damaging to the compilation.
  30  *
  31  * Feature Test Macros must be defined before any system header is included (see
  32  * POSIX 1003.1 2.8.2 "POSIX Symbols."
  33  *
  34  * These macros only have an effect if the operating system supports either
  35  * POSIX 1003.1 or C99, or both.  On other operating systems (particularly
  36  * Windows/Visual Studio) there is no effect; the OS specific tests below are
  37  * still required (as of 2011-05-02.)
  38  */
  39 #define _POSIX_SOURCE 1 /* Just the POSIX 1003.1 and C89 APIs */
  40
  41 /* This is required for the definition of abort(), used as a last ditch
  42  * error handler when all else fails.
  43  */
  44 #include <stdlib.h>
  45
  46 /* This is used to find 'offsetof', used below for alignment tests. */
  47 #include <stddef.h>
  48
  49 #define PNGLIB_BUILD /*libpng is being built, not used*/
  50
  51 #ifdef PNG_USER_CONFIG
  52 #  include "pngusr.h"
  53    /* These should have been defined in pngusr.h */
  54 #  ifndef PNG_USER_PRIVATEBUILD
  55 #    define PNG_USER_PRIVATEBUILD "Custom libpng build"
  56 #  endif
  57 #  ifndef PNG_USER_DLLFNAME_POSTFIX
  58 #    define PNG_USER_DLLFNAME_POSTFIX "Cb"
  59 #  endif
  60 #endif
  61
  62 /* Is this a build of a DLL where compilation of the object modules requires
  63  * different preprocessor settings to those required for a simple library?  If
  64  * so PNG_BUILD_DLL must be set.
  65  *
  66  * If libpng is used inside a DLL but that DLL does not export the libpng APIs
  67  * PNG_BUILD_DLL must not be set.  To avoid the code below kicking in build a
  68  * static library of libpng then link the DLL against that.
  69  */
  70 #ifndef PNG_BUILD_DLL
  71 #  ifdef DLL_EXPORT
  72       /* This is set by libtool when files are compiled for a DLL; libtool
  73        * always compiles twice, even on systems where it isn't necessary.  Set
  74        * PNG_BUILD_DLL in case it is necessary:
  75        */
  76 #     define PNG_BUILD_DLL
  77 #  else
  78 #     ifdef _WINDLL
  79          /* This is set by the Microsoft Visual Studio IDE in projects that
  80           * build a DLL.  It can't easily be removed from those projects (it
  81           * isn't visible in the Visual Studio UI) so it is a fairly reliable
  82           * indication that PNG_IMPEXP needs to be set to the DLL export
  83           * attributes.
  84           */
  85 #        define PNG_BUILD_DLL
  86 #     else
  87 #        ifdef __DLL__
  88             /* This is set by the Borland C system when compiling for a DLL
  89              * (as above.)
  90              */
  91 #           define PNG_BUILD_DLL
  92 #        else
  93             /* Add additional compiler cases here. */
  94 #        endif
  95 #     endif
  96 #  endif
  97 #endif /* Setting PNG_BUILD_DLL if required */
  98
  99 /* See pngconf.h for more details: the builder of the library may set this on
 100  * the command line to the right thing for the specific compilation system or it
 101  * may be automagically set above (at present we know of no system where it does
 102  * need to be set on the command line.)
 103  *
 104  * PNG_IMPEXP must be set here when building the library to prevent pngconf.h
 105  * setting it to the "import" setting for a DLL build.
 106  */
 107 #ifndef PNG_IMPEXP
 108 #  ifdef PNG_BUILD_DLL
 109 #     define PNG_IMPEXP PNG_DLL_EXPORT
 110 #  else
 111       /* Not building a DLL, or the DLL doesn't require specific export
 112        * definitions.
 113        */
 114 #     define PNG_IMPEXP
 115 #  endif
 116 #endif
 117
 118 /* No warnings for private or deprecated functions in the build: */
 119 #ifndef PNG_DEPRECATED
 120 #  define PNG_DEPRECATED
 121 #endif
 122 #ifndef PNG_PRIVATE
 123 #  define PNG_PRIVATE
 124 #endif
 125
 126 #include "png.h"
 127 #include "pnginfo.h"
 128 #include "pngstruct.h"
 129
 130 /* pngconf.h does not set PNG_DLL_EXPORT unless it is required, so: */
 131 #ifndef PNG_DLL_EXPORT
 132 #  define PNG_DLL_EXPORT
 133 #endif
 134
 135 /* This is used for 16 bit gamma tables - only the top level pointers are const,
 136  * this could be changed:
 137  */
 138 typedef PNG_CONST png_uint_16p FAR * png_const_uint_16pp;
 139
 140 /* Added at libpng-1.2.9 */
 141 /* Moved to pngpriv.h at libpng-1.5.0 */
 142
 143 /* config.h is created by and PNG_CONFIGURE_LIBPNG is set by the "configure"
 144  * script.  We may need it here to get the correct configuration on things
 145  * like limits.
 146  */
 147 #ifdef PNG_CONFIGURE_LIBPNG
 148 #  ifdef HAVE_CONFIG_H
 149 #    include "config.h"
 150 #  endif
 151 #endif
 152
 153 /* Moved to pngpriv.h at libpng-1.5.0 */
 154 /* NOTE: some of these may have been used in external applications as
 155  * these definitions were exposed in pngconf.h prior to 1.5.
 156  */
 157
 158 /* If you are running on a machine where you cannot allocate more
 159  * than 64K of memory at once, uncomment this.  While libpng will not
 160  * normally need that much memory in a chunk (unless you load up a very
 161  * large file), zlib needs to know how big of a chunk it can use, and
 162  * libpng thus makes sure to check any memory allocation to verify it
 163  * will fit into memory.
 164  *
 165  * zlib provides 'MAXSEG_64K' which, if defined, indicates the
 166  * same limit and pngconf.h (already included) sets the limit
 167  * if certain operating systems are detected.
 168  */
 169 #if defined(MAXSEG_64K) && !defined(PNG_MAX_MALLOC_64K)
 170 #  define PNG_MAX_MALLOC_64K
 171 #endif
 172
 173 #ifndef PNG_UNUSED
 174 /* Unused formal parameter warnings are silenced using the following macro
 175  * which is expected to have no bad effects on performance (optimizing
 176  * compilers will probably remove it entirely).  Note that if you replace
 177  * it with something other than whitespace, you must include the terminating
 178  * semicolon.
 179  */
 180 #  define PNG_UNUSED(param) (void)param;
 181 #endif
 182
 183 /* Just a little check that someone hasn't tried to define something
 184  * contradictory.
 185  */
 186 #if (PNG_ZBUF_SIZE > 65536L) && defined(PNG_MAX_MALLOC_64K)
 187 #  undef PNG_ZBUF_SIZE
 188 #  define PNG_ZBUF_SIZE 65536L
 189 #endif
 190
 191 /* PNG_STATIC is used to mark internal file scope functions if they need to be
 192  * accessed for implementation tests (see the code in tests/?*).
 193  */
 194 #ifndef PNG_STATIC
 195 #   define PNG_STATIC static
 196 #endif
 197
 198 /* C99 restrict is used where possible, to do this 'restrict' is defined as
 199  * empty if we can't be sure it is supported.  configure builds have already
 200  * done this work.
 201  */
 202 #ifdef PNG_CONFIGURE_LIBPNG
 203 #  define PNG_RESTRICT restrict
 204 #else
 205    /* Modern compilers support restrict, but assume not for anything not
 206     * recognized here:
 207     */
 208 #  if defined __GNUC__ || defined _MSC_VER || defined __WATCOMC__
 209 #     define PNG_RESTRICT restrict
 210 #  else
 211 #     define PNG_RESTRICT
 212 #  endif
 213 #endif
 214
 215 /* If warnings or errors are turned off the code is disabled or redirected here.
 216  * From 1.5.4 functions have been added to allow very limited formatting of
 217  * error and warning messages - this code will also be disabled here.
 218  */
 219 #ifdef PNG_WARNINGS_SUPPORTED
 220 #  define PNG_WARNING_PARAMETERS(p) png_warning_parameters p;
 221 #else
 222 #  define png_warning(s1,s2) ((void)(s1))
 223 #  define png_chunk_warning(s1,s2) ((void)(s1))
 224 #  define png_warning_parameter(p,number,string) ((void)0)
 225 #  define png_warning_parameter_unsigned(p,number,format,value) ((void)0)
 226 #  define png_warning_parameter_signed(p,number,format,value) ((void)0)
 227 #  define png_formatted_warning(pp,p,message) ((void)(pp))
 228 #  define PNG_WARNING_PARAMETERS(p)
 229 #endif
 230 #ifndef PNG_ERROR_TEXT_SUPPORTED
 231 #  define png_error(s1,s2) png_err(s1)
 232 #  define png_chunk_error(s1,s2) png_err(s1)
 233 #  define png_fixed_error(s1,s2) png_err(s1)
 234 #endif
 235
 236 /* C allows up-casts from (void*) to any pointer and (const void*) to any
 237  * pointer to a const object.  C++ regards this as a type error and requires an
 238  * explicit, static, cast and provides the static_cast<> rune to ensure that
 239  * const is not cast away.
 240  */
 241 #ifdef __cplusplus
 242 #  define png_voidcast(type, value) static_cast<type>(value)
 243 #else
 244 #  define png_voidcast(type, value) (value)
 245 #endif /* __cplusplus */
 246
 247 #ifndef PNG_EXTERN
 248 /* The functions exported by PNG_EXTERN are internal functions, which
 249  * aren't usually used outside the library (as far as I know), so it is
 250  * debatable if they should be exported at all.  In the future, when it
 251  * is possible to have run-time registry of chunk-handling functions,
 252  * some of these might be made available again.
 253  *
 254  * 1.5.7: turned the use of 'extern' back on, since it is localized to pngpriv.h
 255  * it should be safe now (it is unclear why it was turned off.)
 256  */
 257 #  define PNG_EXTERN extern
 258 #endif
 259
 260 /* Some fixed point APIs are still required even if not exported because
 261  * they get used by the corresponding floating point APIs.  This magic
 262  * deals with this:
 263  */
 264 #ifdef PNG_FIXED_POINT_SUPPORTED
 265 #  define PNGFAPI PNGAPI
 266 #else
 267 #  define PNGFAPI /* PRIVATE */
 268 #endif
 269
 270 /* Other defines specific to compilers can go here.  Try to keep
 271  * them inside an appropriate ifdef/endif pair for portability.
 272  */
 273 #if defined(PNG_FLOATING_POINT_SUPPORTED) ||\
 274     defined(PNG_FLOATING_ARITHMETIC_SUPPORTED)
 275    /* png.c requires the following ANSI-C constants if the conversion of
 276     * floating point to ASCII is implemented therein:
 277     *
 278     *  DBL_DIG  Maximum number of decimal digits (can be set to any constant)
 279     *  DBL_MIN  Smallest normalized fp number (can be set to an arbitrary value)
 280     *  DBL_MAX  Maximum floating point number (can be set to an arbitrary value)
 281     */
 282 #  include <float.h>
 283
 284 #  if ( ( (defined(__MWERKS__) && defined(macintosh)) || defined(applec) || \
 285     defined(THINK_C) || defined(TARGET_OS_MAC) ) && !wxOSX_USE_IPHONE ) || defined(__SC__)
 286      /* We need to check that <math.h> hasn't already been included earlier
 287       * as it seems it doesn't agree with <fp.h>, yet we should really use
 288       * <fp.h> if possible.
 289       */
 290 #    if !defined(__MATH_H__) && !defined(__MATH_H) && !defined(__cmath__)
 291 #      include <fp.h>
 292 #    endif
 293 #  else
 294 #    include <math.h>
 295 #  endif
 296 #  if defined(_AMIGA) && defined(__SASC) && defined(_M68881)
 297      /* Amiga SAS/C: We must include builtin FPU functions when compiling using
 298       * MATH=68881
 299       */
 300 #    include <m68881.h>
 301 #  endif
 302 #endif
 303
 304 /* This provides the non-ANSI (far) memory allocation routines. */
 305 #if defined(__TURBOC__) && defined(__MSDOS__)
 306 #  include <mem.h>
 307 #  include <alloc.h>
 308 #endif
 309
 310 #if defined(WIN32) || defined(_Windows) || defined(_WINDOWS) || \
 311     defined(_WIN32) || defined(__WIN32__)
 312 #  include <windows.h>  /* defines _WINDOWS_ macro */
 313 #endif
 314
 315 /* Moved here around 1.5.0beta36 from pngconf.h */
 316 /* Users may want to use these so they are not private.  Any library
 317  * functions that are passed far data must be model-independent.
 318  */
 319
 320 /* Memory model/platform independent fns */
 321 #ifndef PNG_ABORT
 322 #  ifdef _WINDOWS_
 323 #    define PNG_ABORT() ExitProcess(0)
 324 #  else
 325 #    define PNG_ABORT() abort()
 326 #  endif
 327 #endif
 328
 329 #ifdef USE_FAR_KEYWORD
 330 /* Use this to make far-to-near assignments */
 331 #  define CHECK   1
 332 #  define NOCHECK 0
 333 #  define CVT_PTR(ptr) (png_far_to_near(png_ptr,ptr,CHECK))
 334 #  define CVT_PTR_NOCHECK(ptr) (png_far_to_near(png_ptr,ptr,NOCHECK))
 335 #  define png_strlen  _fstrlen
 336 #  define png_memcmp  _fmemcmp    /* SJT: added */
 337 #  define png_memcpy  _fmemcpy
 338 #  define png_memset  _fmemset
 339 #else
 340 #  ifdef _WINDOWS_  /* Favor Windows over C runtime fns */
 341 #    define CVT_PTR(ptr)         (ptr)
 342 #    define CVT_PTR_NOCHECK(ptr) (ptr)
 343 #    define png_strlen  lstrlenA
 344 #    define png_memcmp  memcmp
 345 #    define png_memcpy  CopyMemory
 346 #    define png_memset  memset
 347 #  else
 348 #    define CVT_PTR(ptr)         (ptr)
 349 #    define CVT_PTR_NOCHECK(ptr) (ptr)
 350 #    define png_strlen  strlen
 351 #    define png_memcmp  memcmp      /* SJT: added */
 352 #    define png_memcpy  memcpy
 353 #    define png_memset  memset
 354 #  endif
 355 #endif
 356
 357 /* These macros may need to be architecture dependent. */
 358 #define PNG_ALIGN_NONE   0 /* do not use data alignment */
 359 #define PNG_ALIGN_ALWAYS 1 /* assume unaligned accesses are OK */
 360 #ifdef offsetof
 361 #  define PNG_ALIGN_OFFSET 2 /* use offsetof to determine alignment */
 362 #else
 363 #  define PNG_ALIGN_OFFSET -1 /* prevent the use of this */
 364 #endif
 365 #define PNG_ALIGN_SIZE   3 /* use sizeof to determine alignment */
 366
 367 #ifndef PNG_ALIGN_TYPE
 368    /* Default to using aligned access optimizations and requiring alignment to a
 369     * multiple of the data type size.  Override in a compiler specific fashion
 370     * if necessary by inserting tests here:
 371     */
 372 #  define PNG_ALIGN_TYPE PNG_ALIGN_SIZE
 373 #endif
 374
 375 #if PNG_ALIGN_TYPE == PNG_ALIGN_SIZE
 376    /* This is used because in some compiler implementations non-aligned
 377     * structure members are supported, so the offsetof approach below fails.
 378     * Set PNG_ALIGN_TO_SIZE=0 for compiler combinations where unaligned access
 379     * is good for performance.  Do not do this unless you have tested the result
 380     * and understand it.
 381     */
 382 #  define png_alignof(type) (sizeof (type))
 383 #else
 384 #  if PNG_ALIGN_TYPE == PNG_ALIGN_OFFSET
 385 #     define png_alignof(type) offsetof(struct{char c; type t;}, t)
 386 #  else
 387 #     if PNG_ALIGN_TYPE == PNG_ALIGN_ALWAYS
 388 #        define png_alignof(type) (1)
 389 #     endif
 390       /* Else leave png_alignof undefined to prevent use thereof */
 391 #  endif
 392 #endif
 393
 394 /* This implicitly assumes alignment is always to a power of 2. */
 395 #ifdef png_alignof
 396 #  define png_isaligned(ptr, type)\
 397    ((((const char*)ptr-(const char*)0) & (png_alignof(type)-1)) == 0)
 398 #else
 399 #  define png_isaligned(ptr, type) 0
 400 #endif
 401
 402 /* End of memory model/platform independent support */
 403 /* End of 1.5.0beta36 move from pngconf.h */
 404
 405 /* CONSTANTS and UTILITY MACROS
 406  * These are used internally by libpng and not exposed in the API
 407  */
 408
 409 /* Various modes of operation.  Note that after an init, mode is set to
 410  * zero automatically when the structure is created.  Three of these
 411  * are defined in png.h because they need to be visible to applications
 412  * that call png_set_unknown_chunk().
 413  */
 414 /* #define PNG_HAVE_IHDR            0x01 (defined in png.h) */
 415 /* #define PNG_HAVE_PLTE            0x02 (defined in png.h) */
 416 #define PNG_HAVE_IDAT               0x04
 417 /* #define PNG_AFTER_IDAT           0x08 (defined in png.h) */
 418 #define PNG_HAVE_IEND               0x10
 419 #define PNG_HAVE_gAMA               0x20
 420 #define PNG_HAVE_cHRM               0x40
 421 #define PNG_HAVE_sRGB               0x80
 422 #define PNG_HAVE_CHUNK_HEADER      0x100
 423 #define PNG_WROTE_tIME             0x200
 424 #define PNG_WROTE_INFO_BEFORE_PLTE 0x400
 425 #define PNG_BACKGROUND_IS_GRAY     0x800
 426 #define PNG_HAVE_PNG_SIGNATURE    0x1000
 427 #define PNG_HAVE_CHUNK_AFTER_IDAT 0x2000 /* Have another chunk after IDAT */
 428
 429 /* Flags for the transformations the PNG library does on the image data */
 430 #define PNG_BGR                 0x0001
 431 #define PNG_INTERLACE           0x0002
 432 #define PNG_PACK                0x0004
 433 #define PNG_SHIFT               0x0008
 434 #define PNG_SWAP_BYTES          0x0010
 435 #define PNG_INVERT_MONO         0x0020
 436 #define PNG_QUANTIZE            0x0040
 437 #define PNG_COMPOSE             0x0080     /* Was PNG_BACKGROUND */
 438 #define PNG_BACKGROUND_EXPAND   0x0100
 439 #define PNG_EXPAND_16           0x0200     /* Added to libpng 1.5.2 */
 440 #define PNG_16_TO_8             0x0400     /* Becomes 'chop' in 1.5.4 */
 441 #define PNG_RGBA                0x0800
 442 #define PNG_EXPAND              0x1000
 443 #define PNG_GAMMA               0x2000
 444 #define PNG_GRAY_TO_RGB         0x4000
 445 #define PNG_FILLER              0x8000
 446 #define PNG_PACKSWAP           0x10000
 447 #define PNG_SWAP_ALPHA         0x20000
 448 #define PNG_STRIP_ALPHA        0x40000
 449 #define PNG_INVERT_ALPHA       0x80000
 450 #define PNG_USER_TRANSFORM    0x100000
 451 #define PNG_RGB_TO_GRAY_ERR   0x200000
 452 #define PNG_RGB_TO_GRAY_WARN  0x400000
 453 #define PNG_RGB_TO_GRAY       0x600000 /* two bits, RGB_TO_GRAY_ERR|WARN */
 454 #define PNG_ENCODE_ALPHA      0x800000 /* Added to libpng-1.5.4 */
 455 #define PNG_ADD_ALPHA         0x1000000 /* Added to libpng-1.2.7 */
 456 #define PNG_EXPAND_tRNS       0x2000000 /* Added to libpng-1.2.9 */
 457 #define PNG_SCALE_16_TO_8     0x4000000 /* Added to libpng-1.5.4 */
 458                        /*   0x8000000 unused */
 459                        /*  0x10000000 unused */
 460                        /*  0x20000000 unused */
 461                        /*  0x40000000 unused */
 462 /* Flags for png_create_struct */
 463 #define PNG_STRUCT_PNG   0x0001
 464 #define PNG_STRUCT_INFO  0x0002
 465
 466 /* Scaling factor for filter heuristic weighting calculations */
 467 #define PNG_WEIGHT_FACTOR (1<<(PNG_WEIGHT_SHIFT))
 468 #define PNG_COST_FACTOR (1<<(PNG_COST_SHIFT))
 469
 470 /* Flags for the png_ptr->flags rather than declaring a byte for each one */
 471 #define PNG_FLAG_ZLIB_CUSTOM_STRATEGY     0x0001
 472 #define PNG_FLAG_ZLIB_CUSTOM_LEVEL        0x0002
 473 #define PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL    0x0004
 474 #define PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS  0x0008
 475 #define PNG_FLAG_ZLIB_CUSTOM_METHOD       0x0010
 476 #define PNG_FLAG_ZLIB_FINISHED            0x0020
 477 #define PNG_FLAG_ROW_INIT                 0x0040
 478 #define PNG_FLAG_FILLER_AFTER             0x0080
 479 #define PNG_FLAG_CRC_ANCILLARY_USE        0x0100
 480 #define PNG_FLAG_CRC_ANCILLARY_NOWARN     0x0200
 481 #define PNG_FLAG_CRC_CRITICAL_USE         0x0400
 482 #define PNG_FLAG_CRC_CRITICAL_IGNORE      0x0800
 483 #define PNG_FLAG_ASSUME_sRGB              0x1000  /* Added to libpng-1.5.4 */
 484 #define PNG_FLAG_OPTIMIZE_ALPHA           0x2000  /* Added to libpng-1.5.4 */
 485 #define PNG_FLAG_DETECT_UNINITIALIZED     0x4000  /* Added to libpng-1.5.4 */
 486 #define PNG_FLAG_KEEP_UNKNOWN_CHUNKS      0x8000
 487 #define PNG_FLAG_KEEP_UNSAFE_CHUNKS       0x10000
 488 #define PNG_FLAG_LIBRARY_MISMATCH         0x20000
 489 #define PNG_FLAG_STRIP_ERROR_NUMBERS      0x40000
 490 #define PNG_FLAG_STRIP_ERROR_TEXT         0x80000
 491 #define PNG_FLAG_MALLOC_NULL_MEM_OK       0x100000
 492                                   /*      0x200000  unused */
 493                                   /*      0x400000  unused */
 494 #define PNG_FLAG_BENIGN_ERRORS_WARN       0x800000  /* Added to libpng-1.4.0 */
 495 #define PNG_FLAG_ZTXT_CUSTOM_STRATEGY    0x1000000  /* 5 lines added */
 496 #define PNG_FLAG_ZTXT_CUSTOM_LEVEL       0x2000000  /* to libpng-1.5.4 */
 497 #define PNG_FLAG_ZTXT_CUSTOM_MEM_LEVEL   0x4000000
 498 #define PNG_FLAG_ZTXT_CUSTOM_WINDOW_BITS 0x8000000
 499 #define PNG_FLAG_ZTXT_CUSTOM_METHOD      0x10000000
 500                                   /*     0x20000000  unused */
 501                                   /*     0x40000000  unused */
 502
 503 #define PNG_FLAG_CRC_ANCILLARY_MASK (PNG_FLAG_CRC_ANCILLARY_USE | \
 504                                      PNG_FLAG_CRC_ANCILLARY_NOWARN)
 505
 506 #define PNG_FLAG_CRC_CRITICAL_MASK  (PNG_FLAG_CRC_CRITICAL_USE | \
 507                                      PNG_FLAG_CRC_CRITICAL_IGNORE)
 508
 509 #define PNG_FLAG_CRC_MASK           (PNG_FLAG_CRC_ANCILLARY_MASK | \
 510                                      PNG_FLAG_CRC_CRITICAL_MASK)
 511
 512 /* zlib.h declares a magic type 'uInt' that limits the amount of data that zlib
 513  * can handle at once.  This type need be no larger than 16 bits (so maximum of
 514  * 65535), this define allows us to discover how big it is, but limited by the
 515  * maximuum for png_size_t.  The value can be overriden in a library build
 516  * (pngusr.h, or set it in CPPFLAGS) and it works to set it to a considerably
 517  * lower value (e.g. 255 works).  A lower value may help memory usage (slightly)
 518  * and may even improve performance on some systems (and degrade it on others.)
 519  */
 520 #ifndef ZLIB_IO_MAX
 521 #  define ZLIB_IO_MAX ((uInt)-1)
 522 #endif
 523
 524 /* Save typing and make code easier to understand */
 525
 526 #define PNG_COLOR_DIST(c1, c2) (abs((int)((c1).red) - (int)((c2).red)) + \
 527    abs((int)((c1).green) - (int)((c2).green)) + \
 528    abs((int)((c1).blue) - (int)((c2).blue)))
 529
 530 /* Added to libpng-1.2.6 JB */
 531 #define PNG_ROWBYTES(pixel_bits, width) \
 532     ((pixel_bits) >= 8 ? \
 533     ((png_size_t)(width) * (((png_size_t)(pixel_bits)) >> 3)) : \
 534     (( ((png_size_t)(width) * ((png_size_t)(pixel_bits))) + 7) >> 3) )
 535
 536 /* PNG_OUT_OF_RANGE returns true if value is outside the range
 537  * ideal-delta..ideal+delta.  Each argument is evaluated twice.
 538  * "ideal" and "delta" should be constants, normally simple
 539  * integers, "value" a variable. Added to libpng-1.2.6 JB
 540  */
 541 #define PNG_OUT_OF_RANGE(value, ideal, delta) \
 542    ( (value) < (ideal)-(delta) || (value) > (ideal)+(delta) )
 543
 544 /* Conversions between fixed and floating point, only defined if
 545  * required (to make sure the code doesn't accidentally use float
 546  * when it is supposedly disabled.)
 547  */
 548 #ifdef PNG_FLOATING_POINT_SUPPORTED
 549 /* The floating point conversion can't overflow, though it can and
 550  * does lose accuracy relative to the original fixed point value.
 551  * In practice this doesn't matter because png_fixed_point only
 552  * stores numbers with very low precision.  The png_ptr and s
 553  * arguments are unused by default but are there in case error
 554  * checking becomes a requirement.
 555  */
 556 #define png_float(png_ptr, fixed, s) (.00001 * (fixed))
 557
 558 /* The fixed point conversion performs range checking and evaluates
 559  * its argument multiple times, so must be used with care.  The
 560  * range checking uses the PNG specification values for a signed
 561  * 32 bit fixed point value except that the values are deliberately
 562  * rounded-to-zero to an integral value - 21474 (21474.83 is roughly
 563  * (2^31-1) * 100000). 's' is a string that describes the value being
 564  * converted.
 565  *
 566  * NOTE: this macro will raise a png_error if the range check fails,
 567  * therefore it is normally only appropriate to use this on values
 568  * that come from API calls or other sources where an out of range
 569  * error indicates a programming error, not a data error!
 570  *
 571  * NOTE: by default this is off - the macro is not used - because the
 572  * function call saves a lot of code.
 573  */
 574 #ifdef PNG_FIXED_POINT_MACRO_SUPPORTED
 575 #define png_fixed(png_ptr, fp, s) ((fp) <= 21474 && (fp) >= -21474 ?\
 576     ((png_fixed_point)(100000 * (fp))) : (png_fixed_error(png_ptr, s),0))
 577 #else
 578 PNG_EXTERN png_fixed_point png_fixed PNGARG((png_structp png_ptr, double fp,
 579    png_const_charp text));
 580 #endif
 581 #endif
 582
 583 /* Constants for known chunk types.  If you need to add a chunk, define the name
 584  * here.  For historical reasons these constants have the form png_<name>; i.e.
 585  * the prefix is lower case.  Please use decimal values as the parameters to
 586  * match the ISO PNG specification and to avoid relying on the C locale
 587  * interpretation of character values.
 588  *
 589  * Prior to 1.5.6 these constants were strings, as of 1.5.6 png_uint_32 values
 590  * are computed and a new macro (PNG_STRING_FROM_CHUNK) added to allow a string
 591  * to be generated if required.
 592  *
 593  * PNG_32b correctly produces a value shifted by up to 24 bits, even on
 594  * architectures where (int) is only 16 bits.
 595  */
 596 #define PNG_32b(b,s) ((png_uint_32)(b) << (s))
 597 #define PNG_CHUNK(b1,b2,b3,b4) \
 598    (PNG_32b(b1,24) | PNG_32b(b2,16) | PNG_32b(b3,8) | PNG_32b(b4,0))
 599
 600 #define png_IHDR PNG_CHUNK( 73,  72,  68,  82)
 601 #define png_IDAT PNG_CHUNK( 73,  68,  65,  84)
 602 #define png_IEND PNG_CHUNK( 73,  69,  78,  68)
 603 #define png_PLTE PNG_CHUNK( 80,  76,  84,  69)
 604 #define png_bKGD PNG_CHUNK( 98,  75,  71,  68)
 605 #define png_cHRM PNG_CHUNK( 99,  72,  82,  77)
 606 #define png_gAMA PNG_CHUNK(103,  65,  77,  65)
 607 #define png_hIST PNG_CHUNK(104,  73,  83,  84)
 608 #define png_iCCP PNG_CHUNK(105,  67,  67,  80)
 609 #define png_iTXt PNG_CHUNK(105,  84,  88, 116)
 610 #define png_oFFs PNG_CHUNK(111,  70,  70, 115)
 611 #define png_pCAL PNG_CHUNK(112,  67,  65,  76)
 612 #define png_sCAL PNG_CHUNK(115,  67,  65,  76)
 613 #define png_pHYs PNG_CHUNK(112,  72,  89, 115)
 614 #define png_sBIT PNG_CHUNK(115,  66,  73,  84)
 615 #define png_sPLT PNG_CHUNK(115,  80,  76,  84)
 616 #define png_sRGB PNG_CHUNK(115,  82,  71,  66)
 617 #define png_sTER PNG_CHUNK(115,  84,  69,  82)
 618 #define png_tEXt PNG_CHUNK(116,  69,  88, 116)
 619 #define png_tIME PNG_CHUNK(116,  73,  77,  69)
 620 #define png_tRNS PNG_CHUNK(116,  82,  78,  83)
 621 #define png_zTXt PNG_CHUNK(122,  84,  88, 116)
 622
 623 /* The following will work on (signed char*) strings, whereas the get_uint_32
 624  * macro will fail on top-bit-set values because of the sign extension.
 625  */
 626 #define PNG_CHUNK_FROM_STRING(s)\
 627    PNG_CHUNK(0xff&(s)[0], 0xff&(s)[1], 0xff&(s)[2], 0xff&(s)[3])
 628
 629 /* This uses (char), not (png_byte) to avoid warnings on systems where (char) is
 630  * signed and the argument is a (char[])  This macro will fail miserably on
 631  * systems where (char) is more than 8 bits.
 632  */
 633 #define PNG_STRING_FROM_CHUNK(s,c)\
 634    (void)(((char*)(s))[0]=(char)((c)>>24), ((char*)(s))[1]=(char)((c)>>16),\
 635    ((char*)(s))[2]=(char)((c)>>8), ((char*)(s))[3]=(char)((c)))
 636
 637 /* Do the same but terminate with a null character. */
 638 #define PNG_CSTRING_FROM_CHUNK(s,c)\
 639    (void)(PNG_STRING_FROM_CHUNK(s,c), ((char*)(s))[4] = 0)
 640
 641 /* Test on flag values as defined in the spec (section 5.4): */
 642 #define PNG_CHUNK_ANCILLIARY(c)   (1 & ((c) >> 29))
 643 #define PNG_CHUNK_CRITICAL(c)     (!PNG_CHUNK_ANCILLIARY(c))
 644 #define PNG_CHUNK_PRIVATE(c)      (1 & ((c) >> 21))
 645 #define PNG_CHUNK_RESERVED(c)     (1 & ((c) >> 13))
 646 #define PNG_CHUNK_SAFE_TO_COPY(c) (1 & ((c) >>  5))
 647
 648 /* Gamma values (new at libpng-1.5.4): */
 649 #define PNG_GAMMA_MAC_OLD 151724  /* Assume '1.8' is really 2.2/1.45! */
 650 #define PNG_GAMMA_MAC_INVERSE 65909
 651 #define PNG_GAMMA_sRGB_INVERSE 45455
 652
 653
 654 /* Inhibit C++ name-mangling for libpng functions but not for system calls. */
 655 #ifdef __cplusplus
 656 extern "C" {
 657 #endif /* __cplusplus */
 658
 659 /* These functions are used internally in the code.  They generally
 660  * shouldn't be used unless you are writing code to add or replace some
 661  * functionality in libpng.  More information about most functions can
 662  * be found in the files where the functions are located.
 663  */
 664
 665 /* Check the user version string for compatibility, returns false if the version
 666  * numbers aren't compatible.
 667  */
 668 PNG_EXTERN int png_user_version_check(png_structp png_ptr,
 669    png_const_charp user_png_ver);
 670
 671 /* Allocate memory for an internal libpng struct */
 672 PNG_EXTERN PNG_FUNCTION(png_voidp,png_create_struct,PNGARG((int type)),
 673    PNG_ALLOCATED);
 674
 675 /* Free memory from internal libpng struct */
 676 PNG_EXTERN void png_destroy_struct PNGARG((png_voidp struct_ptr));
 677
 678 PNG_EXTERN PNG_FUNCTION(png_voidp,png_create_struct_2,
 679    PNGARG((int type, png_malloc_ptr malloc_fn, png_voidp mem_ptr)),
 680    PNG_ALLOCATED);
 681 PNG_EXTERN void png_destroy_struct_2 PNGARG((png_voidp struct_ptr,
 682     png_free_ptr free_fn, png_voidp mem_ptr));
 683
 684 /* Free any memory that info_ptr points to and reset struct. */
 685 PNG_EXTERN void png_info_destroy PNGARG((png_structp png_ptr,
 686     png_infop info_ptr));
 687
 688 /* Function to allocate memory for zlib.  PNGAPI is disallowed. */
 689 PNG_EXTERN PNG_FUNCTION(voidpf,png_zalloc,PNGARG((voidpf png_ptr, uInt items,
 690    uInt size)),PNG_ALLOCATED);
 691
 692 /* Function to free memory for zlib.  PNGAPI is disallowed. */
 693 PNG_EXTERN void png_zfree PNGARG((voidpf png_ptr, voidpf ptr));
 694
 695 /* Next four functions are used internally as callbacks.  PNGCBAPI is required
 696  * but not PNG_EXPORT.  PNGAPI added at libpng version 1.2.3, changed to
 697  * PNGCBAPI at 1.5.0
 698  */
 699
 700 PNG_EXTERN void PNGCBAPI png_default_read_data PNGARG((png_structp png_ptr,
 701     png_bytep data, png_size_t length));
 702
 703 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
 704 PNG_EXTERN void PNGCBAPI png_push_fill_buffer PNGARG((png_structp png_ptr,
 705     png_bytep buffer, png_size_t length));
 706 #endif
 707
 708 PNG_EXTERN void PNGCBAPI png_default_write_data PNGARG((png_structp png_ptr,
 709     png_bytep data, png_size_t length));
 710
 711 #ifdef PNG_WRITE_FLUSH_SUPPORTED
 712 #  ifdef PNG_STDIO_SUPPORTED
 713 PNG_EXTERN void PNGCBAPI png_default_flush PNGARG((png_structp png_ptr));
 714 #  endif
 715 #endif
 716
 717 /* Reset the CRC variable */
 718 PNG_EXTERN void png_reset_crc PNGARG((png_structp png_ptr));
 719
 720 /* Write the "data" buffer to whatever output you are using */
 721 PNG_EXTERN void png_write_data PNGARG((png_structp png_ptr,
 722     png_const_bytep data, png_size_t length));
 723
 724 /* Read and check the PNG file signature */
 725 PNG_EXTERN void png_read_sig PNGARG((png_structp png_ptr, png_infop info_ptr));
 726
 727 /* Read the chunk header (length + type name) */
 728 PNG_EXTERN png_uint_32 png_read_chunk_header PNGARG((png_structp png_ptr));
 729
 730 /* Read data from whatever input you are using into the "data" buffer */
 731 PNG_EXTERN void png_read_data PNGARG((png_structp png_ptr, png_bytep data,
 732     png_size_t length));
 733
 734 /* Read bytes into buf, and update png_ptr->crc */
 735 PNG_EXTERN void png_crc_read PNGARG((png_structp png_ptr, png_bytep buf,
 736     png_size_t length));
 737
 738 /* Decompress data in a chunk that uses compression */
 739 #if defined(PNG_READ_COMPRESSED_TEXT_SUPPORTED)
 740 PNG_EXTERN void png_decompress_chunk PNGARG((png_structp png_ptr,
 741     int comp_type, png_size_t chunklength, png_size_t prefix_length,
 742     png_size_t *data_length));
 743 #endif
 744
 745 /* Read "skip" bytes, read the file crc, and (optionally) verify png_ptr->crc */
 746 PNG_EXTERN int png_crc_finish PNGARG((png_structp png_ptr, png_uint_32 skip));
 747
 748 /* Read the CRC from the file and compare it to the libpng calculated CRC */
 749 PNG_EXTERN int png_crc_error PNGARG((png_structp png_ptr));
 750
 751 /* Calculate the CRC over a section of data.  Note that we are only
 752  * passing a maximum of 64K on systems that have this as a memory limit,
 753  * since this is the maximum buffer size we can specify.
 754  */
 755 PNG_EXTERN void png_calculate_crc PNGARG((png_structp png_ptr,
 756     png_const_bytep ptr, png_size_t length));
 757
 758 #ifdef PNG_WRITE_FLUSH_SUPPORTED
 759 PNG_EXTERN void png_flush PNGARG((png_structp png_ptr));
 760 #endif
 761
 762 /* Write various chunks */
 763
 764 /* Write the IHDR chunk, and update the png_struct with the necessary
 765  * information.
 766  */
 767 PNG_EXTERN void png_write_IHDR PNGARG((png_structp png_ptr, png_uint_32 width,
 768     png_uint_32 height,
 769     int bit_depth, int color_type, int compression_method, int filter_method,
 770     int interlace_method));
 771
 772 PNG_EXTERN void png_write_PLTE PNGARG((png_structp png_ptr,
 773     png_const_colorp palette, png_uint_32 num_pal));
 774
 775 PNG_EXTERN void png_write_IDAT PNGARG((png_structp png_ptr, png_bytep data,
 776     png_size_t length));
 777
 778 PNG_EXTERN void png_write_IEND PNGARG((png_structp png_ptr));
 779
 780 #ifdef PNG_WRITE_gAMA_SUPPORTED
 781 #  ifdef PNG_FLOATING_POINT_SUPPORTED
 782 PNG_EXTERN void png_write_gAMA PNGARG((png_structp png_ptr, double file_gamma));
 783 #  endif
 784 #  ifdef PNG_FIXED_POINT_SUPPORTED
 785 PNG_EXTERN void png_write_gAMA_fixed PNGARG((png_structp png_ptr,
 786     png_fixed_point file_gamma));
 787 #  endif
 788 #endif
 789
 790 #ifdef PNG_WRITE_sBIT_SUPPORTED
 791 PNG_EXTERN void png_write_sBIT PNGARG((png_structp png_ptr,
 792     png_const_color_8p sbit, int color_type));
 793 #endif
 794
 795 #ifdef PNG_WRITE_cHRM_SUPPORTED
 796 #  ifdef PNG_FLOATING_POINT_SUPPORTED
 797 PNG_EXTERN void png_write_cHRM PNGARG((png_structp png_ptr,
 798     double white_x, double white_y,
 799     double red_x, double red_y, double green_x, double green_y,
 800     double blue_x, double blue_y));
 801 #  endif
 802 PNG_EXTERN void png_write_cHRM_fixed PNGARG((png_structp png_ptr,
 803     png_fixed_point int_white_x, png_fixed_point int_white_y,
 804     png_fixed_point int_red_x, png_fixed_point int_red_y, png_fixed_point
 805     int_green_x, png_fixed_point int_green_y, png_fixed_point int_blue_x,
 806     png_fixed_point int_blue_y));
 807 #endif
 808
 809 #ifdef PNG_WRITE_sRGB_SUPPORTED
 810 PNG_EXTERN void png_write_sRGB PNGARG((png_structp png_ptr,
 811     int intent));
 812 #endif
 813
 814 #ifdef PNG_WRITE_iCCP_SUPPORTED
 815 PNG_EXTERN void png_write_iCCP PNGARG((png_structp png_ptr,
 816     png_const_charp name, int compression_type,
 817     png_const_charp profile, int proflen));
 818    /* Note to maintainer: profile should be png_bytep */
 819 #endif
 820
 821 #ifdef PNG_WRITE_sPLT_SUPPORTED
 822 PNG_EXTERN void png_write_sPLT PNGARG((png_structp png_ptr,
 823     png_const_sPLT_tp palette));
 824 #endif
 825
 826 #ifdef PNG_WRITE_tRNS_SUPPORTED
 827 PNG_EXTERN void png_write_tRNS PNGARG((png_structp png_ptr,
 828     png_const_bytep trans, png_const_color_16p values, int number,
 829     int color_type));
 830 #endif
 831
 832 #ifdef PNG_WRITE_bKGD_SUPPORTED
 833 PNG_EXTERN void png_write_bKGD PNGARG((png_structp png_ptr,
 834     png_const_color_16p values, int color_type));
 835 #endif
 836
 837 #ifdef PNG_WRITE_hIST_SUPPORTED
 838 PNG_EXTERN void png_write_hIST PNGARG((png_structp png_ptr,
 839     png_const_uint_16p hist, int num_hist));
 840 #endif
 841
 842 /* Chunks that have keywords */
 843 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \
 844     defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
 845 PNG_EXTERN png_size_t png_check_keyword PNGARG((png_structp png_ptr,
 846     png_const_charp key, png_charpp new_key));
 847 #endif
 848
 849 #ifdef PNG_WRITE_tEXt_SUPPORTED
 850 PNG_EXTERN void png_write_tEXt PNGARG((png_structp png_ptr, png_const_charp key,
 851     png_const_charp text, png_size_t text_len));
 852 #endif
 853
 854 #ifdef PNG_WRITE_zTXt_SUPPORTED
 855 PNG_EXTERN void png_write_zTXt PNGARG((png_structp png_ptr, png_const_charp key,
 856     png_const_charp text, png_size_t text_len, int compression));
 857 #endif
 858
 859 #ifdef PNG_WRITE_iTXt_SUPPORTED
 860 PNG_EXTERN void png_write_iTXt PNGARG((png_structp png_ptr,
 861     int compression, png_const_charp key, png_const_charp lang,
 862     png_const_charp lang_key, png_const_charp text));
 863 #endif
 864
 865 #ifdef PNG_TEXT_SUPPORTED  /* Added at version 1.0.14 and 1.2.4 */
 866 PNG_EXTERN int png_set_text_2 PNGARG((png_structp png_ptr,
 867     png_infop info_ptr, png_const_textp text_ptr, int num_text));
 868 #endif
 869
 870 #ifdef PNG_WRITE_oFFs_SUPPORTED
 871 PNG_EXTERN void png_write_oFFs PNGARG((png_structp png_ptr,
 872     png_int_32 x_offset, png_int_32 y_offset, int unit_type));
 873 #endif
 874
 875 #ifdef PNG_WRITE_pCAL_SUPPORTED
 876 PNG_EXTERN void png_write_pCAL PNGARG((png_structp png_ptr, png_charp purpose,
 877     png_int_32 X0, png_int_32 X1, int type, int nparams,
 878     png_const_charp units, png_charpp params));
 879 #endif
 880
 881 #ifdef PNG_WRITE_pHYs_SUPPORTED
 882 PNG_EXTERN void png_write_pHYs PNGARG((png_structp png_ptr,
 883     png_uint_32 x_pixels_per_unit, png_uint_32 y_pixels_per_unit,
 884     int unit_type));
 885 #endif
 886
 887 #ifdef PNG_WRITE_tIME_SUPPORTED
 888 PNG_EXTERN void png_write_tIME PNGARG((png_structp png_ptr,
 889     png_const_timep mod_time));
 890 #endif
 891
 892 #ifdef PNG_WRITE_sCAL_SUPPORTED
 893 PNG_EXTERN void png_write_sCAL_s PNGARG((png_structp png_ptr,
 894     int unit, png_const_charp width, png_const_charp height));
 895 #endif
 896
 897 /* Called when finished processing a row of data */
 898 PNG_EXTERN void png_write_finish_row PNGARG((png_structp png_ptr));
 899
 900 /* Internal use only.   Called before first row of data */
 901 PNG_EXTERN void png_write_start_row PNGARG((png_structp png_ptr));
 902
 903 /* Combine a row of data, dealing with alpha, etc. if requested.  'row' is an
 904  * array of png_ptr->width pixels.  If the image is not interlaced or this
 905  * is the final pass this just does a png_memcpy, otherwise the "display" flag
 906  * is used to determine whether to copy pixels that are not in the current pass.
 907  *
 908  * Because 'png_do_read_interlace' (below) replicates pixels this allows this
 909  * function to achieve the documented 'blocky' appearance during interlaced read
 910  * if display is 1 and the 'sparkle' appearance, where existing pixels in 'row'
 911  * are not changed if they are not in the current pass, when display is 0.
 912  *
 913  * 'display' must be 0 or 1, otherwise the memcpy will be done regardless.
 914  *
 915  * The API always reads from the png_struct row buffer and always assumes that
 916  * it is full width (png_do_read_interlace has already been called.)
 917  *
 918  * This function is only ever used to write to row buffers provided by the
 919  * caller of the relevant libpng API and the row must have already been
 920  * transformed by the read transformations.
 921  *
 922  * The PNG_USE_COMPILE_TIME_MASKS option causes generation of pre-computed
 923  * bitmasks for use within the code, otherwise runtime generated masks are used.
 924  * The default is compile time masks.
 925  */
 926 #ifndef PNG_USE_COMPILE_TIME_MASKS
 927 #  define PNG_USE_COMPILE_TIME_MASKS 1
 928 #endif
 929 PNG_EXTERN void png_combine_row PNGARG((png_structp png_ptr, png_bytep row,
 930     int display));
 931
 932 #ifdef PNG_READ_INTERLACING_SUPPORTED
 933 /* Expand an interlaced row: the 'row_info' describes the pass data that has
 934  * been read in and must correspond to the pixels in 'row', the pixels are
 935  * expanded (moved apart) in 'row' to match the final layout, when doing this
 936  * the pixels are *replicated* to the intervening space.  This is essential for
 937  * the correct operation of png_combine_row, above.
 938  */
 939 PNG_EXTERN void png_do_read_interlace PNGARG((png_row_infop row_info,
 940     png_bytep row, int pass, png_uint_32 transformations));
 941 #endif
 942
 943 /* GRR TO DO (2.0 or whenever):  simplify other internal calling interfaces */
 944
 945 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
 946 /* Grab pixels out of a row for an interlaced pass */
 947 PNG_EXTERN void png_do_write_interlace PNGARG((png_row_infop row_info,
 948     png_bytep row, int pass));
 949 #endif
 950
 951 /* Unfilter a row: check the filter value before calling this, there is no point
 952  * calling it for PNG_FILTER_VALUE_NONE.
 953  */
 954 PNG_EXTERN void png_read_filter_row PNGARG((png_structp pp, png_row_infop row_info,
 955     png_bytep row, png_const_bytep prev_row, int filter));
 956
 957 PNG_EXTERN void png_read_filter_row_up_neon PNGARG((png_row_infop row_info,
 958     png_bytep row, png_const_bytep prev_row));
 959 PNG_EXTERN void png_read_filter_row_sub3_neon PNGARG((png_row_infop row_info,
 960     png_bytep row, png_const_bytep prev_row));
 961 PNG_EXTERN void png_read_filter_row_sub4_neon PNGARG((png_row_infop row_info,
 962     png_bytep row, png_const_bytep prev_row));
 963 PNG_EXTERN void png_read_filter_row_avg3_neon PNGARG((png_row_infop row_info,
 964     png_bytep row, png_const_bytep prev_row));
 965 PNG_EXTERN void png_read_filter_row_avg4_neon PNGARG((png_row_infop row_info,
 966     png_bytep row, png_const_bytep prev_row));
 967 PNG_EXTERN void png_read_filter_row_paeth3_neon PNGARG((png_row_infop row_info,
 968     png_bytep row, png_const_bytep prev_row));
 969 PNG_EXTERN void png_read_filter_row_paeth4_neon PNGARG((png_row_infop row_info,
 970     png_bytep row, png_const_bytep prev_row));
 971
 972 /* Choose the best filter to use and filter the row data */
 973 PNG_EXTERN void png_write_find_filter PNGARG((png_structp png_ptr,
 974     png_row_infop row_info));
 975
 976 /* Finish a row while reading, dealing with interlacing passes, etc. */
 977 PNG_EXTERN void png_read_finish_row PNGARG((png_structp png_ptr));
 978
 979 /* Initialize the row buffers, etc. */
 980 PNG_EXTERN void png_read_start_row PNGARG((png_structp png_ptr));
 981
 982 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
 983 /* Optional call to update the users info structure */
 984 PNG_EXTERN void png_read_transform_info PNGARG((png_structp png_ptr,
 985     png_infop info_ptr));
 986 #endif
 987
 988 /* These are the functions that do the transformations */
 989 #ifdef PNG_READ_FILLER_SUPPORTED
 990 PNG_EXTERN void png_do_read_filler PNGARG((png_row_infop row_info,
 991     png_bytep row, png_uint_32 filler, png_uint_32 flags));
 992 #endif
 993
 994 #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
 995 PNG_EXTERN void png_do_read_swap_alpha PNGARG((png_row_infop row_info,
 996     png_bytep row));
 997 #endif
 998
 999 #ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
1000 PNG_EXTERN void png_do_write_swap_alpha PNGARG((png_row_infop row_info,
1001     png_bytep row));
1002 #endif
1003
1004 #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
1005 PNG_EXTERN void png_do_read_invert_alpha PNGARG((png_row_infop row_info,
1006     png_bytep row));
1007 #endif
1008
1009 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
1010 PNG_EXTERN void png_do_write_invert_alpha PNGARG((png_row_infop row_info,
1011     png_bytep row));
1012 #endif
1013
1014 #if defined(PNG_WRITE_FILLER_SUPPORTED) || \
1015     defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
1016 PNG_EXTERN void png_do_strip_channel PNGARG((png_row_infop row_info,
1017     png_bytep row, int at_start));
1018 #endif
1019
1020 #ifdef PNG_16BIT_SUPPORTED
1021 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
1022 PNG_EXTERN void png_do_swap PNGARG((png_row_infop row_info,
1023     png_bytep row));
1024 #endif
1025 #endif
1026
1027 #if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
1028     defined(PNG_WRITE_PACKSWAP_SUPPORTED)
1029 PNG_EXTERN void png_do_packswap PNGARG((png_row_infop row_info,
1030     png_bytep row));
1031 #endif
1032
1033 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1034 PNG_EXTERN int png_do_rgb_to_gray PNGARG((png_structp png_ptr,
1035     png_row_infop row_info, png_bytep row));
1036 #endif
1037
1038 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
1039 PNG_EXTERN void png_do_gray_to_rgb PNGARG((png_row_infop row_info,
1040     png_bytep row));
1041 #endif
1042
1043 #ifdef PNG_READ_PACK_SUPPORTED
1044 PNG_EXTERN void png_do_unpack PNGARG((png_row_infop row_info,
1045     png_bytep row));
1046 #endif
1047
1048 #ifdef PNG_READ_SHIFT_SUPPORTED
1049 PNG_EXTERN void png_do_unshift PNGARG((png_row_infop row_info,
1050     png_bytep row, png_const_color_8p sig_bits));
1051 #endif
1052
1053 #if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
1054 PNG_EXTERN void png_do_invert PNGARG((png_row_infop row_info,
1055     png_bytep row));
1056 #endif
1057
1058 #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
1059 PNG_EXTERN void png_do_scale_16_to_8 PNGARG((png_row_infop row_info,
1060     png_bytep row));
1061 #endif
1062
1063 #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
1064 PNG_EXTERN void png_do_chop PNGARG((png_row_infop row_info,
1065     png_bytep row));
1066 #endif
1067
1068 #ifdef PNG_READ_QUANTIZE_SUPPORTED
1069 PNG_EXTERN void png_do_quantize PNGARG((png_row_infop row_info,
1070     png_bytep row, png_const_bytep palette_lookup,
1071     png_const_bytep quantize_lookup));
1072
1073 #  ifdef PNG_CORRECT_PALETTE_SUPPORTED
1074 PNG_EXTERN void png_correct_palette PNGARG((png_structp png_ptr,
1075     png_colorp palette, int num_palette));
1076 #  endif
1077 #endif
1078
1079 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
1080 PNG_EXTERN void png_do_bgr PNGARG((png_row_infop row_info,
1081     png_bytep row));
1082 #endif
1083
1084 #ifdef PNG_WRITE_PACK_SUPPORTED
1085 PNG_EXTERN void png_do_pack PNGARG((png_row_infop row_info,
1086    png_bytep row, png_uint_32 bit_depth));
1087 #endif
1088
1089 #ifdef PNG_WRITE_SHIFT_SUPPORTED
1090 PNG_EXTERN void png_do_shift PNGARG((png_row_infop row_info,
1091     png_bytep row, png_const_color_8p bit_depth));
1092 #endif
1093
1094 #if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
1095     defined(PNG_READ_ALPHA_MODE_SUPPORTED)
1096 PNG_EXTERN void png_do_compose PNGARG((png_row_infop row_info,
1097     png_bytep row, png_structp png_ptr));
1098 #endif
1099
1100 #ifdef PNG_READ_GAMMA_SUPPORTED
1101 PNG_EXTERN void png_do_gamma PNGARG((png_row_infop row_info,
1102     png_bytep row, png_structp png_ptr));
1103 #endif
1104
1105 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
1106 PNG_EXTERN void png_do_encode_alpha PNGARG((png_row_infop row_info,
1107    png_bytep row, png_structp png_ptr));
1108 #endif
1109
1110 #ifdef PNG_READ_EXPAND_SUPPORTED
1111 PNG_EXTERN void png_do_expand_palette PNGARG((png_row_infop row_info,
1112     png_bytep row, png_const_colorp palette, png_const_bytep trans,
1113     int num_trans));
1114 PNG_EXTERN void png_do_expand PNGARG((png_row_infop row_info,
1115     png_bytep row, png_const_color_16p trans_color));
1116 #endif
1117
1118 #ifdef PNG_READ_EXPAND_16_SUPPORTED
1119 PNG_EXTERN void png_do_expand_16 PNGARG((png_row_infop row_info,
1120     png_bytep row));
1121 #endif
1122
1123 /* The following decodes the appropriate chunks, and does error correction,
1124  * then calls the appropriate callback for the chunk if it is valid.
1125  */
1126
1127 /* Decode the IHDR chunk */
1128 PNG_EXTERN void png_handle_IHDR PNGARG((png_structp png_ptr, png_infop info_ptr,
1129     png_uint_32 length));
1130 PNG_EXTERN void png_handle_PLTE PNGARG((png_structp png_ptr, png_infop info_ptr,
1131     png_uint_32 length));
1132 PNG_EXTERN void png_handle_IEND PNGARG((png_structp png_ptr, png_infop info_ptr,
1133     png_uint_32 length));
1134
1135 #ifdef PNG_READ_bKGD_SUPPORTED
1136 PNG_EXTERN void png_handle_bKGD PNGARG((png_structp png_ptr, png_infop info_ptr,
1137     png_uint_32 length));
1138 #endif
1139
1140 #ifdef PNG_READ_cHRM_SUPPORTED
1141 PNG_EXTERN void png_handle_cHRM PNGARG((png_structp png_ptr, png_infop info_ptr,
1142     png_uint_32 length));
1143 #endif
1144
1145 #ifdef PNG_READ_gAMA_SUPPORTED
1146 PNG_EXTERN void png_handle_gAMA PNGARG((png_structp png_ptr, png_infop info_ptr,
1147     png_uint_32 length));
1148 #endif
1149
1150 #ifdef PNG_READ_hIST_SUPPORTED
1151 PNG_EXTERN void png_handle_hIST PNGARG((png_structp png_ptr, png_infop info_ptr,
1152     png_uint_32 length));
1153 #endif
1154
1155 #ifdef PNG_READ_iCCP_SUPPORTED
1156 PNG_EXTERN void png_handle_iCCP PNGARG((png_structp png_ptr, png_infop info_ptr,
1157     png_uint_32 length));
1158 #endif /* PNG_READ_iCCP_SUPPORTED */
1159
1160 #ifdef PNG_READ_iTXt_SUPPORTED
1161 PNG_EXTERN void png_handle_iTXt PNGARG((png_structp png_ptr, png_infop info_ptr,
1162     png_uint_32 length));
1163 #endif
1164
1165 #ifdef PNG_READ_oFFs_SUPPORTED
1166 PNG_EXTERN void png_handle_oFFs PNGARG((png_structp png_ptr, png_infop info_ptr,
1167     png_uint_32 length));
1168 #endif
1169
1170 #ifdef PNG_READ_pCAL_SUPPORTED
1171 PNG_EXTERN void png_handle_pCAL PNGARG((png_structp png_ptr, png_infop info_ptr,
1172     png_uint_32 length));
1173 #endif
1174
1175 #ifdef PNG_READ_pHYs_SUPPORTED
1176 PNG_EXTERN void png_handle_pHYs PNGARG((png_structp png_ptr, png_infop info_ptr,
1177     png_uint_32 length));
1178 #endif
1179
1180 #ifdef PNG_READ_sBIT_SUPPORTED
1181 PNG_EXTERN void png_handle_sBIT PNGARG((png_structp png_ptr, png_infop info_ptr,
1182     png_uint_32 length));
1183 #endif
1184
1185 #ifdef PNG_READ_sCAL_SUPPORTED
1186 PNG_EXTERN void png_handle_sCAL PNGARG((png_structp png_ptr, png_infop info_ptr,
1187     png_uint_32 length));
1188 #endif
1189
1190 #ifdef PNG_READ_sPLT_SUPPORTED
1191 PNG_EXTERN void png_handle_sPLT PNGARG((png_structp png_ptr, png_infop info_ptr,
1192     png_uint_32 length));
1193 #endif /* PNG_READ_sPLT_SUPPORTED */
1194
1195 #ifdef PNG_READ_sRGB_SUPPORTED
1196 PNG_EXTERN void png_handle_sRGB PNGARG((png_structp png_ptr, png_infop info_ptr,
1197     png_uint_32 length));
1198 #endif
1199
1200 #ifdef PNG_READ_tEXt_SUPPORTED
1201 PNG_EXTERN void png_handle_tEXt PNGARG((png_structp png_ptr, png_infop info_ptr,
1202     png_uint_32 length));
1203 #endif
1204
1205 #ifdef PNG_READ_tIME_SUPPORTED
1206 PNG_EXTERN void png_handle_tIME PNGARG((png_structp png_ptr, png_infop info_ptr,
1207     png_uint_32 length));
1208 #endif
1209
1210 #ifdef PNG_READ_tRNS_SUPPORTED
1211 PNG_EXTERN void png_handle_tRNS PNGARG((png_structp png_ptr, png_infop info_ptr,
1212     png_uint_32 length));
1213 #endif
1214
1215 #ifdef PNG_READ_zTXt_SUPPORTED
1216 PNG_EXTERN void png_handle_zTXt PNGARG((png_structp png_ptr, png_infop info_ptr,
1217     png_uint_32 length));
1218 #endif
1219
1220 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
1221 PNG_EXTERN void png_handle_unknown PNGARG((png_structp png_ptr,
1222     png_infop info_ptr, png_uint_32 length));
1223 #endif
1224
1225 PNG_EXTERN void png_check_chunk_name PNGARG((png_structp png_ptr,
1226     png_uint_32 chunk_name));
1227
1228 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
1229 /* Exactly as png_handle_as_unknown() except that the argument is a 32-bit chunk
1230  * name, not a string.
1231  */
1232 PNG_EXTERN int png_chunk_unknown_handling PNGARG((png_structp png_ptr,
1233     png_uint_32 chunk_name));
1234 #endif
1235
1236 /* Handle the transformations for reading and writing */
1237 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1238 PNG_EXTERN void png_do_read_transformations PNGARG((png_structp png_ptr,
1239    png_row_infop row_info));
1240 #endif
1241 #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
1242 PNG_EXTERN void png_do_write_transformations PNGARG((png_structp png_ptr,
1243    png_row_infop row_info));
1244 #endif
1245
1246 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1247 PNG_EXTERN void png_init_read_transformations PNGARG((png_structp png_ptr));
1248 #endif
1249
1250 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1251 PNG_EXTERN void png_push_read_chunk PNGARG((png_structp png_ptr,
1252     png_infop info_ptr));
1253 PNG_EXTERN void png_push_read_sig PNGARG((png_structp png_ptr,
1254     png_infop info_ptr));
1255 PNG_EXTERN void png_push_check_crc PNGARG((png_structp png_ptr));
1256 PNG_EXTERN void png_push_crc_skip PNGARG((png_structp png_ptr,
1257     png_uint_32 length));
1258 PNG_EXTERN void png_push_crc_finish PNGARG((png_structp png_ptr));
1259 PNG_EXTERN void png_push_save_buffer PNGARG((png_structp png_ptr));
1260 PNG_EXTERN void png_push_restore_buffer PNGARG((png_structp png_ptr,
1261     png_bytep buffer, png_size_t buffer_length));
1262 PNG_EXTERN void png_push_read_IDAT PNGARG((png_structp png_ptr));
1263 PNG_EXTERN void png_process_IDAT_data PNGARG((png_structp png_ptr,
1264     png_bytep buffer, png_size_t buffer_length));
1265 PNG_EXTERN void png_push_process_row PNGARG((png_structp png_ptr));
1266 PNG_EXTERN void png_push_handle_unknown PNGARG((png_structp png_ptr,
1267    png_infop info_ptr, png_uint_32 length));
1268 PNG_EXTERN void png_push_have_info PNGARG((png_structp png_ptr,
1269    png_infop info_ptr));
1270 PNG_EXTERN void png_push_have_end PNGARG((png_structp png_ptr,
1271    png_infop info_ptr));
1272 PNG_EXTERN void png_push_have_row PNGARG((png_structp png_ptr, png_bytep row));
1273 PNG_EXTERN void png_push_read_end PNGARG((png_structp png_ptr,
1274     png_infop info_ptr));
1275 PNG_EXTERN void png_process_some_data PNGARG((png_structp png_ptr,
1276     png_infop info_ptr));
1277 PNG_EXTERN void png_read_push_finish_row PNGARG((png_structp png_ptr));
1278 #  ifdef PNG_READ_tEXt_SUPPORTED
1279 PNG_EXTERN void png_push_handle_tEXt PNGARG((png_structp png_ptr,
1280     png_infop info_ptr, png_uint_32 length));
1281 PNG_EXTERN void png_push_read_tEXt PNGARG((png_structp png_ptr,
1282     png_infop info_ptr));
1283 #  endif
1284 #  ifdef PNG_READ_zTXt_SUPPORTED
1285 PNG_EXTERN void png_push_handle_zTXt PNGARG((png_structp png_ptr,
1286     png_infop info_ptr, png_uint_32 length));
1287 PNG_EXTERN void png_push_read_zTXt PNGARG((png_structp png_ptr,
1288     png_infop info_ptr));
1289 #  endif
1290 #  ifdef PNG_READ_iTXt_SUPPORTED
1291 PNG_EXTERN void png_push_handle_iTXt PNGARG((png_structp png_ptr,
1292     png_infop info_ptr, png_uint_32 length));
1293 PNG_EXTERN void png_push_read_iTXt PNGARG((png_structp png_ptr,
1294     png_infop info_ptr));
1295 #  endif
1296
1297 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
1298
1299 #ifdef PNG_MNG_FEATURES_SUPPORTED
1300 PNG_EXTERN void png_do_read_intrapixel PNGARG((png_row_infop row_info,
1301     png_bytep row));
1302 PNG_EXTERN void png_do_write_intrapixel PNGARG((png_row_infop row_info,
1303     png_bytep row));
1304 #endif
1305
1306 /* Added at libpng version 1.4.0 */
1307 #ifdef PNG_CHECK_cHRM_SUPPORTED
1308 PNG_EXTERN int png_check_cHRM_fixed PNGARG((png_structp png_ptr,
1309     png_fixed_point int_white_x, png_fixed_point int_white_y,
1310     png_fixed_point int_red_x, png_fixed_point int_red_y, png_fixed_point
1311     int_green_x, png_fixed_point int_green_y, png_fixed_point int_blue_x,
1312     png_fixed_point int_blue_y));
1313 #endif
1314
1315 #ifdef PNG_CHECK_cHRM_SUPPORTED
1316 /* Added at libpng version 1.2.34 and 1.4.0 */
1317 /* Currently only used by png_check_cHRM_fixed */
1318 PNG_EXTERN void png_64bit_product PNGARG((long v1, long v2,
1319     unsigned long *hi_product, unsigned long *lo_product));
1320 #endif
1321
1322 #ifdef PNG_cHRM_SUPPORTED
1323 /* Added at libpng version 1.5.5 */
1324 typedef struct png_xy
1325 {
1326    png_fixed_point redx, redy;
1327    png_fixed_point greenx, greeny;
1328    png_fixed_point bluex, bluey;
1329    png_fixed_point whitex, whitey;
1330 } png_xy;
1331
1332 typedef struct png_XYZ
1333 {
1334    png_fixed_point redX, redY, redZ;
1335    png_fixed_point greenX, greenY, greenZ;
1336    png_fixed_point blueX, blueY, blueZ;
1337 } png_XYZ;
1338
1339 /* The conversion APIs return 0 on success, non-zero on a parameter error. They
1340  * allow conversion between the above representations of a color encoding.  When
1341  * converting from XYZ end points to chromaticities the absolute magnitude of
1342  * the end points is lost, when converting back the sum of the Y values of the
1343  * three end points will be 1.0
1344  */
1345 PNG_EXTERN int png_xy_from_XYZ PNGARG((png_xy *xy, png_XYZ XYZ));
1346 PNG_EXTERN int png_XYZ_from_xy PNGARG((png_XYZ *XYZ, png_xy xy));
1347 PNG_EXTERN int png_XYZ_from_xy_checked PNGARG((png_structp png_ptr,
1348    png_XYZ *XYZ, png_xy xy));
1349 #endif
1350
1351 /* Added at libpng version 1.4.0 */
1352 PNG_EXTERN void png_check_IHDR PNGARG((png_structp png_ptr,
1353     png_uint_32 width, png_uint_32 height, int bit_depth,
1354     int color_type, int interlace_type, int compression_type,
1355     int filter_type));
1356
1357 /* Free all memory used by the read (old method - NOT DLL EXPORTED) */
1358 PNG_EXTERN void png_read_destroy PNGARG((png_structp png_ptr,
1359     png_infop info_ptr, png_infop end_info_ptr));
1360
1361 /* Free any memory used in png_ptr struct (old method - NOT DLL EXPORTED) */
1362 PNG_EXTERN void png_write_destroy PNGARG((png_structp png_ptr));
1363
1364 #ifdef USE_FAR_KEYWORD  /* memory model conversion function */
1365 PNG_EXTERN void *png_far_to_near PNGARG((png_structp png_ptr, png_voidp ptr,
1366     int check));
1367 #endif /* USE_FAR_KEYWORD */
1368
1369 #if defined(PNG_FLOATING_POINT_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED)
1370 PNG_EXTERN PNG_FUNCTION(void, png_fixed_error, (png_structp png_ptr,
1371    png_const_charp name),PNG_NORETURN);
1372 #endif
1373
1374 /* Puts 'string' into 'buffer' at buffer[pos], taking care never to overwrite
1375  * the end.  Always leaves the buffer nul terminated.  Never errors out (and
1376  * there is no error code.)
1377  */
1378 PNG_EXTERN size_t png_safecat(png_charp buffer, size_t bufsize, size_t pos,
1379     png_const_charp string);
1380
1381 /* Various internal functions to handle formatted warning messages, currently
1382  * only implemented for warnings.
1383  */
1384 #if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_TIME_RFC1123_SUPPORTED)
1385 /* Utility to dump an unsigned value into a buffer, given a start pointer and
1386  * and end pointer (which should point just *beyond* the end of the buffer!)
1387  * Returns the pointer to the start of the formatted string.  This utility only
1388  * does unsigned values.
1389  */
1390 PNG_EXTERN png_charp png_format_number(png_const_charp start, png_charp end,
1391    int format, png_alloc_size_t number);
1392
1393 /* Convenience macro that takes an array: */
1394 #define PNG_FORMAT_NUMBER(buffer,format,number) \
1395    png_format_number(buffer, buffer + (sizeof buffer), format, number)
1396
1397 /* Suggested size for a number buffer (enough for 64 bits and a sign!) */
1398 #define PNG_NUMBER_BUFFER_SIZE 24
1399
1400 /* These are the integer formats currently supported, the name is formed from
1401  * the standard printf(3) format string.
1402  */
1403 #define PNG_NUMBER_FORMAT_u     1 /* chose unsigned API! */
1404 #define PNG_NUMBER_FORMAT_02u   2
1405 #define PNG_NUMBER_FORMAT_d     1 /* chose signed API! */
1406 #define PNG_NUMBER_FORMAT_02d   2
1407 #define PNG_NUMBER_FORMAT_x     3
1408 #define PNG_NUMBER_FORMAT_02x   4
1409 #define PNG_NUMBER_FORMAT_fixed 5 /* choose the signed API */
1410 #endif
1411
1412 #ifdef PNG_WARNINGS_SUPPORTED
1413 /* New defines and members adding in libpng-1.5.4 */
1414 #  define PNG_WARNING_PARAMETER_SIZE 32
1415 #  define PNG_WARNING_PARAMETER_COUNT 8
1416
1417 /* An l-value of this type has to be passed to the APIs below to cache the
1418  * values of the parameters to a formatted warning message.
1419  */
1420 typedef char png_warning_parameters[PNG_WARNING_PARAMETER_COUNT][
1421    PNG_WARNING_PARAMETER_SIZE];
1422
1423 PNG_EXTERN void png_warning_parameter(png_warning_parameters p, int number,
1424     png_const_charp string);
1425     /* Parameters are limited in size to PNG_WARNING_PARAMETER_SIZE characters,
1426      * including the trailing '\0'.
1427      */
1428 PNG_EXTERN void png_warning_parameter_unsigned(png_warning_parameters p,
1429     int number, int format, png_alloc_size_t value);
1430     /* Use png_alloc_size_t because it is an unsigned type as big as any we
1431      * need to output.  Use the following for a signed value.
1432      */
1433 PNG_EXTERN void png_warning_parameter_signed(png_warning_parameters p,
1434     int number, int format, png_int_32 value);
1435
1436 PNG_EXTERN void png_formatted_warning(png_structp png_ptr,
1437     png_warning_parameters p, png_const_charp message);
1438     /* 'message' follows the X/Open approach of using @1, @2 to insert
1439      * parameters previously supplied using the above functions.  Errors in
1440      * specifying the paramters will simple result in garbage substitutions.
1441      */
1442 #endif
1443
1444 /* ASCII to FP interfaces, currently only implemented if sCAL
1445  * support is required.
1446  */
1447 #if defined(PNG_READ_sCAL_SUPPORTED)
1448 /* MAX_DIGITS is actually the maximum number of characters in an sCAL
1449  * width or height, derived from the precision (number of significant
1450  * digits - a build time settable option) and assumpitions about the
1451  * maximum ridiculous exponent.
1452  */
1453 #define PNG_sCAL_MAX_DIGITS (PNG_sCAL_PRECISION+1/*.*/+1/*E*/+10/*exponent*/)
1454
1455 #ifdef PNG_FLOATING_POINT_SUPPORTED
1456 PNG_EXTERN void png_ascii_from_fp PNGARG((png_structp png_ptr, png_charp ascii,
1457     png_size_t size, double fp, unsigned int precision));
1458 #endif /* FLOATING_POINT */
1459
1460 #ifdef PNG_FIXED_POINT_SUPPORTED
1461 PNG_EXTERN void png_ascii_from_fixed PNGARG((png_structp png_ptr,
1462     png_charp ascii, png_size_t size, png_fixed_point fp));
1463 #endif /* FIXED_POINT */
1464 #endif /* READ_sCAL */
1465
1466 #if defined(PNG_sCAL_SUPPORTED) || defined(PNG_pCAL_SUPPORTED)
1467 /* An internal API to validate the format of a floating point number.
1468  * The result is the index of the next character.  If the number is
1469  * not valid it will be the index of a character in the supposed number.
1470  *
1471  * The format of a number is defined in the PNG extensions specification
1472  * and this API is strictly conformant to that spec, not anyone elses!
1473  *
1474  * The format as a regular expression is:
1475  *
1476  * [+-]?[0-9]+.?([Ee][+-]?[0-9]+)?
1477  *
1478  * or:
1479  *
1480  * [+-]?.[0-9]+(.[0-9]+)?([Ee][+-]?[0-9]+)?
1481  *
1482  * The complexity is that either integer or fraction must be present and the
1483  * fraction is permitted to have no digits only if the integer is present.
1484  *
1485  * NOTE: The dangling E problem.
1486  *   There is a PNG valid floating point number in the following:
1487  *
1488  *       PNG floating point numb1.ers are not greedy.
1489  *
1490  *   Working this out requires *TWO* character lookahead (because of the
1491  *   sign), the parser does not do this - it will fail at the 'r' - this
1492  *   doesn't matter for PNG sCAL chunk values, but it requires more care
1493  *   if the value were ever to be embedded in something more complex.  Use
1494  *   ANSI-C strtod if you need the lookahead.
1495  */
1496 /* State table for the parser. */
1497 #define PNG_FP_INTEGER    0  /* before or in integer */
1498 #define PNG_FP_FRACTION   1  /* before or in fraction */
1499 #define PNG_FP_EXPONENT   2  /* before or in exponent */
1500 #define PNG_FP_STATE      3  /* mask for the above */
1501 #define PNG_FP_SAW_SIGN   4  /* Saw +/- in current state */
1502 #define PNG_FP_SAW_DIGIT  8  /* Saw a digit in current state */
1503 #define PNG_FP_SAW_DOT   16  /* Saw a dot in current state */
1504 #define PNG_FP_SAW_E     32  /* Saw an E (or e) in current state */
1505 #define PNG_FP_SAW_ANY   60  /* Saw any of the above 4 */
1506
1507 /* These three values don't affect the parser.  They are set but not used.
1508  */
1509 #define PNG_FP_WAS_VALID 64  /* Preceding substring is a valid fp number */
1510 #define PNG_FP_NEGATIVE 128  /* A negative number, including "-0" */
1511 #define PNG_FP_NONZERO  256  /* A non-zero value */
1512 #define PNG_FP_STICKY   448  /* The above three flags */
1513
1514 /* This is available for the caller to store in 'state' if required.  Do not
1515  * call the parser after setting it (the parser sometimes clears it.)
1516  */
1517 #define PNG_FP_INVALID  512  /* Available for callers as a distinct value */
1518
1519 /* Result codes for the parser (boolean - true meants ok, false means
1520  * not ok yet.)
1521  */
1522 #define PNG_FP_MAYBE      0  /* The number may be valid in the future */
1523 #define PNG_FP_OK         1  /* The number is valid */
1524
1525 /* Tests on the sticky non-zero and negative flags.  To pass these checks
1526  * the state must also indicate that the whole number is valid - this is
1527  * achieved by testing PNG_FP_SAW_DIGIT (see the implementation for why this
1528  * is equivalent to PNG_FP_OK above.)
1529  */
1530 #define PNG_FP_NZ_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NEGATIVE | PNG_FP_NONZERO)
1531    /* NZ_MASK: the string is valid and a non-zero negative value */
1532 #define PNG_FP_Z_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NONZERO)
1533    /* Z MASK: the string is valid and a non-zero value. */
1534    /* PNG_FP_SAW_DIGIT: the string is valid. */
1535 #define PNG_FP_IS_ZERO(state) (((state) & PNG_FP_Z_MASK) == PNG_FP_SAW_DIGIT)
1536 #define PNG_FP_IS_POSITIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_Z_MASK)
1537 #define PNG_FP_IS_NEGATIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_NZ_MASK)
1538
1539 /* The actual parser.  This can be called repeatedly, it updates
1540  * the index into the string and the state variable (which must
1541  * be initialzed to 0).  It returns a result code, as above.  There
1542  * is no point calling the parser any more if it fails to advance to
1543  * the end of the string - it is stuck on an invalid character (or
1544  * terminated by '\0').
1545  *
1546  * Note that the pointer will consume an E or even an E+ then leave
1547  * a 'maybe' state even though a preceding integer.fraction is valid.
1548  * The PNG_FP_WAS_VALID flag indicates that a preceding substring was
1549  * a valid number.  It's possible to recover from this by calling
1550  * the parser again (from the start, with state 0) but with a string
1551  * that omits the last character (i.e. set the size to the index of
1552  * the problem character.)  This has not been tested within libpng.
1553  */
1554 PNG_EXTERN int png_check_fp_number PNGARG((png_const_charp string,
1555     png_size_t size, int *statep, png_size_tp whereami));
1556
1557 /* This is the same but it checks a complete string and returns true
1558  * only if it just contains a floating point number.  As of 1.5.4 this
1559  * function also returns the state at the end of parsing the number if
1560  * it was valid (otherwise it returns 0.)  This can be used for testing
1561  * for negative or zero values using the sticky flag.
1562  */
1563 PNG_EXTERN int png_check_fp_string PNGARG((png_const_charp string,
1564     png_size_t size));
1565 #endif /* pCAL || sCAL */
1566
1567 #if defined(PNG_READ_GAMMA_SUPPORTED) ||\
1568     defined(PNG_INCH_CONVERSIONS_SUPPORTED) || defined(PNG_READ_pHYs_SUPPORTED)
1569 /* Added at libpng version 1.5.0 */
1570 /* This is a utility to provide a*times/div (rounded) and indicate
1571  * if there is an overflow.  The result is a boolean - false (0)
1572  * for overflow, true (1) if no overflow, in which case *res
1573  * holds the result.
1574  */
1575 PNG_EXTERN int png_muldiv PNGARG((png_fixed_point_p res, png_fixed_point a,
1576     png_int_32 multiplied_by, png_int_32 divided_by));
1577 #endif
1578
1579 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_INCH_CONVERSIONS_SUPPORTED)
1580 /* Same deal, but issue a warning on overflow and return 0. */
1581 PNG_EXTERN png_fixed_point png_muldiv_warn PNGARG((png_structp png_ptr,
1582     png_fixed_point a, png_int_32 multiplied_by, png_int_32 divided_by));
1583 #endif
1584
1585 #ifdef PNG_READ_GAMMA_SUPPORTED
1586 /* Calculate a reciprocal - used for gamma values.  This returns
1587  * 0 if the argument is 0 in order to maintain an undefined value,
1588  * there are no warnings.
1589  */
1590 PNG_EXTERN png_fixed_point png_reciprocal PNGARG((png_fixed_point a));
1591
1592 /* The same but gives a reciprocal of the product of two fixed point
1593  * values.  Accuracy is suitable for gamma calculations but this is
1594  * not exact - use png_muldiv for that.
1595  */
1596 PNG_EXTERN png_fixed_point png_reciprocal2 PNGARG((png_fixed_point a,
1597     png_fixed_point b));
1598 #endif
1599
1600 #ifdef PNG_READ_GAMMA_SUPPORTED
1601 /* Internal fixed point gamma correction.  These APIs are called as
1602  * required to convert single values - they don't need to be fast,
1603  * they are not used when processing image pixel values.
1604  *
1605  * While the input is an 'unsigned' value it must actually be the
1606  * correct bit value - 0..255 or 0..65535 as required.
1607  */
1608 PNG_EXTERN png_uint_16 png_gamma_correct PNGARG((png_structp png_ptr,
1609     unsigned int value, png_fixed_point gamma_value));
1610 PNG_EXTERN int png_gamma_significant PNGARG((png_fixed_point gamma_value));
1611 PNG_EXTERN png_uint_16 png_gamma_16bit_correct PNGARG((unsigned int value,
1612     png_fixed_point gamma_value));
1613 PNG_EXTERN png_byte png_gamma_8bit_correct PNGARG((unsigned int value,
1614     png_fixed_point gamma_value));
1615 PNG_EXTERN void png_destroy_gamma_table(png_structp png_ptr);
1616 PNG_EXTERN void png_build_gamma_table PNGARG((png_structp png_ptr,
1617     int bit_depth));
1618 #endif
1619
1620 /* Maintainer: Put new private prototypes here ^ and in libpngpf.3 */
1621
1622 #include "pngdebug.h"
1623
1624 #ifdef __cplusplus
1625 }
1626 #endif
1627
1628 #endif /* PNGPRIV_H */