1 /*
   2  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   3  *
   4  * This code is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License version 2 only, as
   6  * published by the Free Software Foundation.  Oracle designates this
   7  * particular file as subject to the "Classpath" exception as provided
   8  * by Oracle in the LICENSE file that accompanied this code.
   9  *
  10  * This code is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License version
  17  * 2 along with this work; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21  * or visit www.oracle.com if you need additional information or have any
  22  * questions.
  23  */
  24 
  25 /* pngpriv.h - private declarations for use inside libpng
  26  *
  27  * This file is available under and governed by the GNU General Public
  28  * License version 2 only, as published by the Free Software Foundation.
  29  * However, the following notice accompanied the original version of this
  30  * file and, per its terms, should not be removed:
  31  *
  32  * For conditions of distribution and use, see copyright notice in png.h
  33  * Copyright (c) 1998-2014 Glenn Randers-Pehrson
  34  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  35  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  36  *
  37  * Last changed in libpng 1.6.10 [March 6, 1014]]
  38  *
  39  * This code is released under the libpng license.
  40  * For conditions of distribution and use, see the disclaimer
  41  * and license in png.h
  42  */
  43 
  44 /* The symbols declared in this file (including the functions declared
  45  * as extern) are PRIVATE.  They are not part of the libpng public
  46  * interface, and are not recommended for use by regular applications.
  47  * Some of them may become public in the future; others may stay private,
  48  * change in an incompatible way, or even disappear.
  49  * Although the libpng users are not forbidden to include this header,
  50  * they should be well aware of the issues that may arise from doing so.
  51  */
  52 
  53 #ifndef PNGPRIV_H
  54 #define PNGPRIV_H
  55 
  56 /* Feature Test Macros.  The following are defined here to ensure that correctly
  57  * implemented libraries reveal the APIs libpng needs to build and hide those
  58  * that are not needed and potentially damaging to the compilation.
  59  *
  60  * Feature Test Macros must be defined before any system header is included (see
  61  * POSIX 1003.1 2.8.2 "POSIX Symbols."
  62  *
  63  * These macros only have an effect if the operating system supports either
  64  * POSIX 1003.1 or C99, or both.  On other operating systems (particularly
  65  * Windows/Visual Studio) there is no effect; the OS specific tests below are
  66  * still required (as of 2011-05-02.)
  67  */
  68 #define _POSIX_SOURCE 1 /* Just the POSIX 1003.1 and C89 APIs */
  69 
  70 #ifndef PNG_VERSION_INFO_ONLY
  71 /* Standard library headers not required by png.h: */
  72 #  include <stdlib.h>
  73 #  include <string.h>
  74 #endif
  75 
  76 #define PNGLIB_BUILD /*libpng is being built, not used*/
  77 
  78 /* If HAVE_CONFIG_H is defined during the build then the build system must
  79  * provide an appropriate "config.h" file on the include path.  The header file
  80  * must provide definitions as required below (search for "HAVE_CONFIG_H");
  81  * see configure.ac for more details of the requirements.  The macro
  82  * "PNG_NO_CONFIG_H" is provided for maintainers to test for dependencies on
  83  * 'configure'; define this macro to prevent the configure build including the
  84  * configure generated config.h.  Libpng is expected to compile without *any*
  85  * special build system support on a reasonably ANSI-C compliant system.
  86  */
  87 #if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
  88 #  include <config.h>
  89 
  90    /* Pick up the definition of 'restrict' from config.h if it was read: */
  91 #  define PNG_RESTRICT restrict
  92 #endif
  93 
  94 /* To support symbol prefixing it is necessary to know *before* including png.h
  95  * whether the fixed point (and maybe other) APIs are exported, because if they
  96  * are not internal definitions may be required.  This is handled below just
  97  * before png.h is included, but load the configuration now if it is available.
  98  */
  99 #ifndef PNGLCONF_H
 100 #  include "pnglibconf.h"
 101 #endif
 102 
 103 /* Local renames may change non-exported API functions from png.h */
 104 #if defined(PNG_PREFIX) && !defined(PNGPREFIX_H)
 105 #  include "pngprefix.h"
 106 #endif
 107 
 108 #ifdef PNG_USER_CONFIG
 109 #  include "pngusr.h"
 110    /* These should have been defined in pngusr.h */
 111 #  ifndef PNG_USER_PRIVATEBUILD
 112 #    define PNG_USER_PRIVATEBUILD "Custom libpng build"
 113 #  endif
 114 #  ifndef PNG_USER_DLLFNAME_POSTFIX
 115 #    define PNG_USER_DLLFNAME_POSTFIX "Cb"
 116 #  endif
 117 #endif
 118 
 119 /* Compile time options.
 120  * =====================
 121  * In a multi-arch build the compiler may compile the code several times for the
 122  * same object module, producing different binaries for different architectures.
 123  * When this happens configure-time setting of the target host options cannot be
 124  * done and this interferes with the handling of the ARM NEON optimizations, and
 125  * possibly other similar optimizations.  Put additional tests here; in general
 126  * this is needed when the same option can be changed at both compile time and
 127  * run time depending on the target OS (i.e. iOS vs Android.)
 128  *
 129  * NOTE: symbol prefixing does not pass $(CFLAGS) to the preprocessor, because
 130  * this is not possible with certain compilers (Oracle SUN OS CC), as a result
 131  * it is necessary to ensure that all extern functions that *might* be used
 132  * regardless of $(CFLAGS) get declared in this file.  The test on __ARM_NEON__
 133  * below is one example of this behavior because it is controlled by the
 134  * presence or not of -mfpu=neon on the GCC command line, it is possible to do
 135  * this in $(CC), e.g. "CC=gcc -mfpu=neon", but people who build libpng rarely
 136  * do this.
 137  */
 138 #ifndef PNG_ARM_NEON_OPT
 139    /* ARM NEON optimizations are being controlled by the compiler settings,
 140     * typically the target FPU.  If the FPU has been set to NEON (-mfpu=neon
 141     * with GCC) then the compiler will define __ARM_NEON__ and we can rely
 142     * unconditionally on NEON instructions not crashing, otherwise we must
 143     * disable use of NEON instructions.
 144     *
 145     * NOTE: at present these optimizations depend on 'ALIGNED_MEMORY', so they
 146     * can only be turned on automatically if that is supported too.  If
 147     * PNG_ARM_NEON_OPT is set in CPPFLAGS (to >0) then arm/arm_init.c will fail
 148     * to compile with an appropriate #error if ALIGNED_MEMORY has been turned
 149     * off.
 150     *
 151     * Note that gcc-4.9 defines __ARM_NEON instead of __ARM_NEON__, so we
 152     * check both variants.
 153     */
 154 #  if (defined(__ARM_NEON__) || defined(__ARM_NEON)) && \
 155    defined(PNG_ALIGNED_MEMORY_SUPPORTED)
 156 #     define PNG_ARM_NEON_OPT 2
 157 #  else
 158 #     define PNG_ARM_NEON_OPT 0
 159 #  endif
 160 #endif
 161 
 162 #if PNG_ARM_NEON_OPT > 0
 163    /* NEON optimizations are to be at least considered by libpng, so enable the
 164     * callbacks to do this.
 165     */
 166 #  define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_neon
 167 
 168    /* By default the 'intrinsics' code in arm/filter_neon_intrinsics.c is used
 169     * if possible - if __ARM_NEON__ is set and the compiler version is not known
 170     * to be broken.  This is controlled by PNG_ARM_NEON_IMPLEMENTATION which can
 171     * be:
 172     *
 173     *    1  The intrinsics code (the default with __ARM_NEON__)
 174     *    2  The hand coded assembler (the default without __ARM_NEON__)
 175     *
 176     * It is possible to set PNG_ARM_NEON_IMPLEMENTATION in CPPFLAGS, however
 177     * this is *NOT* supported and may cease to work even after a minor revision
 178     * to libpng.  It *is* valid to do this for testing purposes, e.g. speed
 179     * testing or a new compiler, but the results should be communicated to the
 180     * libpng implementation list for incorporation in the next minor release.
 181     */
 182 #  ifndef PNG_ARM_NEON_IMPLEMENTATION
 183 #     if defined(__ARM_NEON__) || defined(__ARM_NEON)
 184 #        if defined(__clang__)
 185             /* At present it is unknown by the libpng developers which versions
 186              * of clang support the intrinsics, however some or perhaps all
 187              * versions do not work with the assembler so this may be
 188              * irrelevant, so just use the default (do nothing here.)
 189              */
 190 #        elif defined(__GNUC__)
 191             /* GCC 4.5.4 NEON support is known to be broken.  4.6.3 is known to
 192              * work, so if this *is* GCC, or G++, look for a version >4.5
 193              */
 194 #           if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 6)
 195 #              define PNG_ARM_NEON_IMPLEMENTATION 2
 196 #           endif /* no GNUC support */
 197 #        endif /* __GNUC__ */
 198 #     else /* !defined __ARM_NEON__ */
 199          /* The 'intrinsics' code simply won't compile without this -mfpu=neon:
 200           */
 201 #        define PNG_ARM_NEON_IMPLEMENTATION 2
 202 #     endif /* __ARM_NEON__ */
 203 #  endif /* !PNG_ARM_NEON_IMPLEMENTATION */
 204 
 205 #  ifndef PNG_ARM_NEON_IMPLEMENTATION
 206       /* Use the intrinsics code by default. */
 207 #     define PNG_ARM_NEON_IMPLEMENTATION 1
 208 #  endif
 209 #endif /* PNG_ARM_NEON_OPT > 0 */
 210 
 211 /* Is this a build of a DLL where compilation of the object modules requires
 212  * different preprocessor settings to those required for a simple library?  If
 213  * so PNG_BUILD_DLL must be set.
 214  *
 215  * If libpng is used inside a DLL but that DLL does not export the libpng APIs
 216  * PNG_BUILD_DLL must not be set.  To avoid the code below kicking in build a
 217  * static library of libpng then link the DLL against that.
 218  */
 219 #ifndef PNG_BUILD_DLL
 220 #  ifdef DLL_EXPORT
 221       /* This is set by libtool when files are compiled for a DLL; libtool
 222        * always compiles twice, even on systems where it isn't necessary.  Set
 223        * PNG_BUILD_DLL in case it is necessary:
 224        */
 225 #     define PNG_BUILD_DLL
 226 #  else
 227 #     ifdef _WINDLL
 228          /* This is set by the Microsoft Visual Studio IDE in projects that
 229           * build a DLL.  It can't easily be removed from those projects (it
 230           * isn't visible in the Visual Studio UI) so it is a fairly reliable
 231           * indication that PNG_IMPEXP needs to be set to the DLL export
 232           * attributes.
 233           */
 234 #        define PNG_BUILD_DLL
 235 #     else
 236 #        ifdef __DLL__
 237             /* This is set by the Borland C system when compiling for a DLL
 238              * (as above.)
 239              */
 240 #           define PNG_BUILD_DLL
 241 #        else
 242             /* Add additional compiler cases here. */
 243 #        endif
 244 #     endif
 245 #  endif
 246 #endif /* Setting PNG_BUILD_DLL if required */
 247 
 248 /* See pngconf.h for more details: the builder of the library may set this on
 249  * the command line to the right thing for the specific compilation system or it
 250  * may be automagically set above (at present we know of no system where it does
 251  * need to be set on the command line.)
 252  *
 253  * PNG_IMPEXP must be set here when building the library to prevent pngconf.h
 254  * setting it to the "import" setting for a DLL build.
 255  */
 256 #ifndef PNG_IMPEXP
 257 #  ifdef PNG_BUILD_DLL
 258 #     define PNG_IMPEXP PNG_DLL_EXPORT
 259 #  else
 260       /* Not building a DLL, or the DLL doesn't require specific export
 261        * definitions.
 262        */
 263 #     define PNG_IMPEXP
 264 #  endif
 265 #endif
 266 
 267 /* No warnings for private or deprecated functions in the build: */
 268 #ifndef PNG_DEPRECATED
 269 #  define PNG_DEPRECATED
 270 #endif
 271 #ifndef PNG_PRIVATE
 272 #  define PNG_PRIVATE
 273 #endif
 274 
 275 /* Symbol preprocessing support.
 276  *
 277  * To enable listing global, but internal, symbols the following macros should
 278  * always be used to declare an extern data or function object in this file.
 279  */
 280 #ifndef PNG_INTERNAL_DATA
 281 #  define PNG_INTERNAL_DATA(type, name, array) extern type name array
 282 #endif
 283 
 284 #ifndef PNG_INTERNAL_FUNCTION
 285 #  define PNG_INTERNAL_FUNCTION(type, name, args, attributes)\
 286       extern PNG_FUNCTION(type, name, args, PNG_EMPTY attributes)
 287 #endif
 288 
 289 #ifndef PNG_INTERNAL_CALLBACK
 290 #  define PNG_INTERNAL_CALLBACK(type, name, args, attributes)\
 291       extern PNG_FUNCTION(type, (PNGCBAPI name), args, PNG_EMPTY attributes)
 292 #endif
 293 
 294 /* If floating or fixed point APIs are disabled they may still be compiled
 295  * internally.  To handle this make sure they are declared as the appropriate
 296  * internal extern function (otherwise the symbol prefixing stuff won't work and
 297  * the functions will be used without definitions.)
 298  *
 299  * NOTE: although all the API functions are declared here they are not all
 300  * actually built!  Because the declarations are still made it is necessary to
 301  * fake out types that they depend on.
 302  */
 303 #ifndef PNG_FP_EXPORT
 304 #  ifndef PNG_FLOATING_POINT_SUPPORTED
 305 #     define PNG_FP_EXPORT(ordinal, type, name, args)\
 306          PNG_INTERNAL_FUNCTION(type, name, args, PNG_EMPTY);
 307 #     ifndef PNG_VERSION_INFO_ONLY
 308          typedef struct png_incomplete png_double;
 309          typedef png_double*           png_doublep;
 310          typedef const png_double*     png_const_doublep;
 311          typedef png_double**          png_doublepp;
 312 #     endif
 313 #  endif
 314 #endif
 315 #ifndef PNG_FIXED_EXPORT
 316 #  ifndef PNG_FIXED_POINT_SUPPORTED
 317 #     define PNG_FIXED_EXPORT(ordinal, type, name, args)\
 318          PNG_INTERNAL_FUNCTION(type, name, args, PNG_EMPTY);
 319 #  endif
 320 #endif
 321 
 322 #include "png.h"
 323 
 324 /* pngconf.h does not set PNG_DLL_EXPORT unless it is required, so: */
 325 #ifndef PNG_DLL_EXPORT
 326 #  define PNG_DLL_EXPORT
 327 #endif
 328 
 329 /* SECURITY and SAFETY:
 330  *
 331  * By default libpng is built without any internal limits on image size,
 332  * individual heap (png_malloc) allocations or the total amount of memory used.
 333  * If PNG_SAFE_LIMITS_SUPPORTED is defined, however, the limits below are used
 334  * (unless individually overridden).  These limits are believed to be fairly
 335  * safe, but builders of secure systems should verify the values against the
 336  * real system capabilities.
 337  */
 338 #ifdef PNG_SAFE_LIMITS_SUPPORTED
 339    /* 'safe' limits */
 340 #  ifndef PNG_USER_WIDTH_MAX
 341 #     define PNG_USER_WIDTH_MAX 1000000
 342 #  endif
 343 #  ifndef PNG_USER_HEIGHT_MAX
 344 #     define PNG_USER_HEIGHT_MAX 1000000
 345 #  endif
 346 #  ifndef PNG_USER_CHUNK_CACHE_MAX
 347 #     define PNG_USER_CHUNK_CACHE_MAX 128
 348 #  endif
 349 #  ifndef PNG_USER_CHUNK_MALLOC_MAX
 350 #     define PNG_USER_CHUNK_MALLOC_MAX 8000000
 351 #  endif
 352 #else
 353    /* values for no limits */
 354 #  ifndef PNG_USER_WIDTH_MAX
 355 #     define PNG_USER_WIDTH_MAX 0x7fffffff
 356 #  endif
 357 #  ifndef PNG_USER_HEIGHT_MAX
 358 #     define PNG_USER_HEIGHT_MAX 0x7fffffff
 359 #  endif
 360 #  ifndef PNG_USER_CHUNK_CACHE_MAX
 361 #     define PNG_USER_CHUNK_CACHE_MAX 0
 362 #  endif
 363 #  ifndef PNG_USER_CHUNK_MALLOC_MAX
 364 #     define PNG_USER_CHUNK_MALLOC_MAX 0
 365 #  endif
 366 #endif
 367 
 368 /* Moved to pngpriv.h at libpng-1.5.0 */
 369 /* NOTE: some of these may have been used in external applications as
 370  * these definitions were exposed in pngconf.h prior to 1.5.
 371  */
 372 
 373 /* If you are running on a machine where you cannot allocate more
 374  * than 64K of memory at once, uncomment this.  While libpng will not
 375  * normally need that much memory in a chunk (unless you load up a very
 376  * large file), zlib needs to know how big of a chunk it can use, and
 377  * libpng thus makes sure to check any memory allocation to verify it
 378  * will fit into memory.
 379  *
 380  * zlib provides 'MAXSEG_64K' which, if defined, indicates the
 381  * same limit and pngconf.h (already included) sets the limit
 382  * if certain operating systems are detected.
 383  */
 384 #if defined(MAXSEG_64K) && !defined(PNG_MAX_MALLOC_64K)
 385 #  define PNG_MAX_MALLOC_64K
 386 #endif
 387 
 388 #ifndef PNG_UNUSED
 389 /* Unused formal parameter warnings are silenced using the following macro
 390  * which is expected to have no bad effects on performance (optimizing
 391  * compilers will probably remove it entirely).  Note that if you replace
 392  * it with something other than whitespace, you must include the terminating
 393  * semicolon.
 394  */
 395 #  define PNG_UNUSED(param) (void)param;
 396 #endif
 397 
 398 /* Just a little check that someone hasn't tried to define something
 399  * contradictory.
 400  */
 401 #if (PNG_ZBUF_SIZE > 65536L) && defined(PNG_MAX_MALLOC_64K)
 402 #  undef PNG_ZBUF_SIZE
 403 #  define PNG_ZBUF_SIZE 65536L
 404 #endif
 405 
 406 /* If warnings or errors are turned off the code is disabled or redirected here.
 407  * From 1.5.4 functions have been added to allow very limited formatting of
 408  * error and warning messages - this code will also be disabled here.
 409  */
 410 #ifdef PNG_WARNINGS_SUPPORTED
 411 #  define PNG_WARNING_PARAMETERS(p) png_warning_parameters p;
 412 #else
 413 #  define png_warning_parameter(p,number,string) ((void)0)
 414 #  define png_warning_parameter_unsigned(p,number,format,value) ((void)0)
 415 #  define png_warning_parameter_signed(p,number,format,value) ((void)0)
 416 #  define png_formatted_warning(pp,p,message) ((void)(pp))
 417 #  define PNG_WARNING_PARAMETERS(p)
 418 #endif
 419 #ifndef PNG_ERROR_TEXT_SUPPORTED
 420 #  define png_fixed_error(s1,s2) png_err(s1)
 421 #endif
 422 
 423 /* C allows up-casts from (void*) to any pointer and (const void*) to any
 424  * pointer to a const object.  C++ regards this as a type error and requires an
 425  * explicit, static, cast and provides the static_cast<> rune to ensure that
 426  * const is not cast away.
 427  */
 428 #ifdef __cplusplus
 429 #  define png_voidcast(type, value) static_cast<type>(value)
 430 #  define png_constcast(type, value) const_cast<type>(value)
 431 #  define png_aligncast(type, value) \
 432    static_cast<type>(static_cast<void*>(value))
 433 #  define png_aligncastconst(type, value) \
 434    static_cast<type>(static_cast<const void*>(value))
 435 #else
 436 #  define png_voidcast(type, value) (value)
 437 #  define png_constcast(type, value) ((type)(value))
 438 #  define png_aligncast(type, value) ((void*)(value))
 439 #  define png_aligncastconst(type, value) ((const void*)(value))
 440 #endif /* __cplusplus */
 441 
 442 /* Some fixed point APIs are still required even if not exported because
 443  * they get used by the corresponding floating point APIs.  This magic
 444  * deals with this:
 445  */
 446 #ifdef PNG_FIXED_POINT_SUPPORTED
 447 #  define PNGFAPI PNGAPI
 448 #else
 449 #  define PNGFAPI /* PRIVATE */
 450 #endif
 451 
 452 #ifndef PNG_VERSION_INFO_ONLY
 453 /* Other defines specific to compilers can go here.  Try to keep
 454  * them inside an appropriate ifdef/endif pair for portability.
 455  */
 456 #if defined(PNG_FLOATING_POINT_SUPPORTED) ||\
 457     defined(PNG_FLOATING_ARITHMETIC_SUPPORTED)
 458    /* png.c requires the following ANSI-C constants if the conversion of
 459     * floating point to ASCII is implemented therein:
 460     *
 461     *  DBL_DIG  Maximum number of decimal digits (can be set to any constant)
 462     *  DBL_MIN  Smallest normalized fp number (can be set to an arbitrary value)
 463     *  DBL_MAX  Maximum floating point number (can be set to an arbitrary value)
 464     */
 465 #  include <float.h>
 466 
 467 #  if (defined(__MWERKS__) && defined(macintosh)) || defined(applec) || \
 468     defined(THINK_C) || defined(__SC__) || defined(TARGET_OS_MAC)
 469      /* We need to check that <math.h> hasn't already been included earlier
 470       * as it seems it doesn't agree with <fp.h>, yet we should really use
 471       * <fp.h> if possible.
 472       */
 473 #    if !defined(__MATH_H__) && !defined(__MATH_H) && !defined(__cmath__)
 474 #      include <fp.h>
 475 #    endif
 476 #  else
 477 #    include <math.h>
 478 #  endif
 479 #  if defined(_AMIGA) && defined(__SASC) && defined(_M68881)
 480      /* Amiga SAS/C: We must include builtin FPU functions when compiling using
 481       * MATH=68881
 482       */
 483 #    include <m68881.h>
 484 #  endif
 485 #endif
 486 
 487 /* This provides the non-ANSI (far) memory allocation routines. */
 488 #if defined(__TURBOC__) && defined(__MSDOS__)
 489 #  include <mem.h>
 490 #  include <alloc.h>
 491 #endif
 492 
 493 #if defined(WIN32) || defined(_Windows) || defined(_WINDOWS) || \
 494     defined(_WIN32) || defined(__WIN32__)
 495 #  include <windows.h>  /* defines _WINDOWS_ macro */
 496 #endif
 497 #endif /* PNG_VERSION_INFO_ONLY */
 498 
 499 /* Moved here around 1.5.0beta36 from pngconf.h */
 500 /* Users may want to use these so they are not private.  Any library
 501  * functions that are passed far data must be model-independent.
 502  */
 503 
 504 /* Memory model/platform independent fns */
 505 #ifndef PNG_ABORT
 506 #  ifdef _WINDOWS_
 507 #    define PNG_ABORT() ExitProcess(0)
 508 #  else
 509 #    define PNG_ABORT() abort()
 510 #  endif
 511 #endif
 512 
 513 /* These macros may need to be architecture dependent. */
 514 #define PNG_ALIGN_NONE   0 /* do not use data alignment */
 515 #define PNG_ALIGN_ALWAYS 1 /* assume unaligned accesses are OK */
 516 #ifdef offsetof
 517 #  define PNG_ALIGN_OFFSET 2 /* use offsetof to determine alignment */
 518 #else
 519 #  define PNG_ALIGN_OFFSET -1 /* prevent the use of this */
 520 #endif
 521 #define PNG_ALIGN_SIZE   3 /* use sizeof to determine alignment */
 522 
 523 #ifndef PNG_ALIGN_TYPE
 524    /* Default to using aligned access optimizations and requiring alignment to a
 525     * multiple of the data type size.  Override in a compiler specific fashion
 526     * if necessary by inserting tests here:
 527     */
 528 #  define PNG_ALIGN_TYPE PNG_ALIGN_SIZE
 529 #endif
 530 
 531 #if PNG_ALIGN_TYPE == PNG_ALIGN_SIZE
 532    /* This is used because in some compiler implementations non-aligned
 533     * structure members are supported, so the offsetof approach below fails.
 534     * Set PNG_ALIGN_SIZE=0 for compiler combinations where unaligned access
 535     * is good for performance.  Do not do this unless you have tested the result
 536     * and understand it.
 537     */
 538 #  define png_alignof(type) (sizeof (type))
 539 #else
 540 #  if PNG_ALIGN_TYPE == PNG_ALIGN_OFFSET
 541 #     define png_alignof(type) offsetof(struct{char c; type t;}, t)
 542 #  else
 543 #     if PNG_ALIGN_TYPE == PNG_ALIGN_ALWAYS
 544 #        define png_alignof(type) (1)
 545 #     endif
 546       /* Else leave png_alignof undefined to prevent use thereof */
 547 #  endif
 548 #endif
 549 
 550 /* This implicitly assumes alignment is always to a power of 2. */
 551 #ifdef png_alignof
 552 #  define png_isaligned(ptr, type)\
 553    ((((const char*)ptr-(const char*)0) & (png_alignof(type)-1)) == 0)
 554 #else
 555 #  define png_isaligned(ptr, type) 0
 556 #endif
 557 
 558 /* End of memory model/platform independent support */
 559 /* End of 1.5.0beta36 move from pngconf.h */
 560 
 561 /* CONSTANTS and UTILITY MACROS
 562  * These are used internally by libpng and not exposed in the API
 563  */
 564 
 565 /* Various modes of operation.  Note that after an init, mode is set to
 566  * zero automatically when the structure is created.  Three of these
 567  * are defined in png.h because they need to be visible to applications
 568  * that call png_set_unknown_chunk().
 569  */
 570 /* #define PNG_HAVE_IHDR            0x01 (defined in png.h) */
 571 /* #define PNG_HAVE_PLTE            0x02 (defined in png.h) */
 572 #define PNG_HAVE_IDAT               0x04
 573 /* #define PNG_AFTER_IDAT           0x08 (defined in png.h) */
 574 #define PNG_HAVE_IEND               0x10
 575                    /*               0x20 (unused) */
 576                    /*               0x40 (unused) */
 577                    /*               0x80 (unused) */
 578 #define PNG_HAVE_CHUNK_HEADER      0x100
 579 #define PNG_WROTE_tIME             0x200
 580 #define PNG_WROTE_INFO_BEFORE_PLTE 0x400
 581 #define PNG_BACKGROUND_IS_GRAY     0x800
 582 #define PNG_HAVE_PNG_SIGNATURE    0x1000
 583 #define PNG_HAVE_CHUNK_AFTER_IDAT 0x2000 /* Have another chunk after IDAT */
 584                    /*             0x4000 (unused) */
 585 #define PNG_IS_READ_STRUCT        0x8000 /* Else is a write struct */
 586 
 587 /* Flags for the transformations the PNG library does on the image data */
 588 #define PNG_BGR                 0x0001
 589 #define PNG_INTERLACE           0x0002
 590 #define PNG_PACK                0x0004
 591 #define PNG_SHIFT               0x0008
 592 #define PNG_SWAP_BYTES          0x0010
 593 #define PNG_INVERT_MONO         0x0020
 594 #define PNG_QUANTIZE            0x0040
 595 #define PNG_COMPOSE             0x0080     /* Was PNG_BACKGROUND */
 596 #define PNG_BACKGROUND_EXPAND   0x0100
 597 #define PNG_EXPAND_16           0x0200     /* Added to libpng 1.5.2 */
 598 #define PNG_16_TO_8             0x0400     /* Becomes 'chop' in 1.5.4 */
 599 #define PNG_RGBA                0x0800
 600 #define PNG_EXPAND              0x1000
 601 #define PNG_GAMMA               0x2000
 602 #define PNG_GRAY_TO_RGB         0x4000
 603 #define PNG_FILLER              0x8000
 604 #define PNG_PACKSWAP           0x10000
 605 #define PNG_SWAP_ALPHA         0x20000
 606 #define PNG_STRIP_ALPHA        0x40000
 607 #define PNG_INVERT_ALPHA       0x80000
 608 #define PNG_USER_TRANSFORM    0x100000
 609 #define PNG_RGB_TO_GRAY_ERR   0x200000
 610 #define PNG_RGB_TO_GRAY_WARN  0x400000
 611 #define PNG_RGB_TO_GRAY       0x600000 /* two bits, RGB_TO_GRAY_ERR|WARN */
 612 #define PNG_ENCODE_ALPHA      0x800000 /* Added to libpng-1.5.4 */
 613 #define PNG_ADD_ALPHA         0x1000000 /* Added to libpng-1.2.7 */
 614 #define PNG_EXPAND_tRNS       0x2000000 /* Added to libpng-1.2.9 */
 615 #define PNG_SCALE_16_TO_8     0x4000000 /* Added to libpng-1.5.4 */
 616                        /*   0x8000000 unused */
 617                        /*  0x10000000 unused */
 618                        /*  0x20000000 unused */
 619                        /*  0x40000000 unused */
 620 /* Flags for png_create_struct */
 621 #define PNG_STRUCT_PNG   0x0001
 622 #define PNG_STRUCT_INFO  0x0002
 623 
 624 /* Scaling factor for filter heuristic weighting calculations */
 625 #define PNG_WEIGHT_FACTOR (1<<(PNG_WEIGHT_SHIFT))
 626 #define PNG_COST_FACTOR (1<<(PNG_COST_SHIFT))
 627 
 628 /* Flags for the png_ptr->flags rather than declaring a byte for each one */
 629 #define PNG_FLAG_ZLIB_CUSTOM_STRATEGY     0x0001
 630 #define PNG_FLAG_ZSTREAM_INITIALIZED      0x0002 /* Added to libpng-1.6.0 */
 631                                   /*      0x0004    unused */
 632 #define PNG_FLAG_ZSTREAM_ENDED            0x0008 /* Added to libpng-1.6.0 */
 633                                   /*      0x0010    unused */
 634                                   /*      0x0020    unused */
 635 #define PNG_FLAG_ROW_INIT                 0x0040
 636 #define PNG_FLAG_FILLER_AFTER             0x0080
 637 #define PNG_FLAG_CRC_ANCILLARY_USE        0x0100
 638 #define PNG_FLAG_CRC_ANCILLARY_NOWARN     0x0200
 639 #define PNG_FLAG_CRC_CRITICAL_USE         0x0400
 640 #define PNG_FLAG_CRC_CRITICAL_IGNORE      0x0800
 641 #define PNG_FLAG_ASSUME_sRGB              0x1000 /* Added to libpng-1.5.4 */
 642 #define PNG_FLAG_OPTIMIZE_ALPHA           0x2000 /* Added to libpng-1.5.4 */
 643 #define PNG_FLAG_DETECT_UNINITIALIZED     0x4000 /* Added to libpng-1.5.4 */
 644 /* #define PNG_FLAG_KEEP_UNKNOWN_CHUNKS      0x8000 */
 645 /* #define PNG_FLAG_KEEP_UNSAFE_CHUNKS      0x10000 */
 646 #define PNG_FLAG_LIBRARY_MISMATCH        0x20000
 647 #define PNG_FLAG_STRIP_ERROR_NUMBERS     0x40000
 648 #define PNG_FLAG_STRIP_ERROR_TEXT        0x80000
 649 #define PNG_FLAG_BENIGN_ERRORS_WARN     0x100000 /* Added to libpng-1.4.0 */
 650 #define PNG_FLAG_APP_WARNINGS_WARN      0x200000 /* Added to libpng-1.6.0 */
 651 #define PNG_FLAG_APP_ERRORS_WARN        0x400000 /* Added to libpng-1.6.0 */
 652                                   /*    0x800000    unused */
 653                                   /*   0x1000000    unused */
 654                                   /*   0x2000000    unused */
 655                                   /*   0x4000000    unused */
 656                                   /*   0x8000000    unused */
 657                                   /*  0x10000000    unused */
 658                                   /*  0x20000000    unused */
 659                                   /*  0x40000000    unused */
 660 
 661 #define PNG_FLAG_CRC_ANCILLARY_MASK (PNG_FLAG_CRC_ANCILLARY_USE | \
 662                                      PNG_FLAG_CRC_ANCILLARY_NOWARN)
 663 
 664 #define PNG_FLAG_CRC_CRITICAL_MASK  (PNG_FLAG_CRC_CRITICAL_USE | \
 665                                      PNG_FLAG_CRC_CRITICAL_IGNORE)
 666 
 667 #define PNG_FLAG_CRC_MASK           (PNG_FLAG_CRC_ANCILLARY_MASK | \
 668                                      PNG_FLAG_CRC_CRITICAL_MASK)
 669 
 670 /* Save typing and make code easier to understand */
 671 
 672 #define PNG_COLOR_DIST(c1, c2) (abs((int)((c1).red) - (int)((c2).red)) + \
 673    abs((int)((c1).green) - (int)((c2).green)) + \
 674    abs((int)((c1).blue) - (int)((c2).blue)))
 675 
 676 /* Added to libpng-1.6.0: scale a 16-bit value in the range 0..65535 to 0..255
 677  * by dividing by 257 *with rounding*.  This macro is exact for the given range.
 678  * See the discourse in pngrtran.c png_do_scale_16_to_8.  The values in the
 679  * macro were established by experiment (modifying the added value).  The macro
 680  * has a second variant that takes a value already scaled by 255 and divides by
 681  * 65535 - this has a maximum error of .502.  Over the range 0..65535*65535 it
 682  * only gives off-by-one errors and only for 0.5% (1 in 200) of the values.
 683  */
 684 #define PNG_DIV65535(v24) (((v24) + 32895) >> 16)
 685 #define PNG_DIV257(v16) PNG_DIV65535((png_uint_32)(v16) * 255)
 686 
 687 /* Added to libpng-1.2.6 JB */
 688 #define PNG_ROWBYTES(pixel_bits, width) \
 689     ((pixel_bits) >= 8 ? \
 690     ((png_size_t)(width) * (((png_size_t)(pixel_bits)) >> 3)) : \
 691     (( ((png_size_t)(width) * ((png_size_t)(pixel_bits))) + 7) >> 3) )
 692 
 693 /* PNG_OUT_OF_RANGE returns true if value is outside the range
 694  * ideal-delta..ideal+delta.  Each argument is evaluated twice.
 695  * "ideal" and "delta" should be constants, normally simple
 696  * integers, "value" a variable. Added to libpng-1.2.6 JB
 697  */
 698 #define PNG_OUT_OF_RANGE(value, ideal, delta) \
 699    ( (value) < (ideal)-(delta) || (value) > (ideal)+(delta) )
 700 
 701 /* Conversions between fixed and floating point, only defined if
 702  * required (to make sure the code doesn't accidentally use float
 703  * when it is supposedly disabled.)
 704  */
 705 #ifdef PNG_FLOATING_POINT_SUPPORTED
 706 /* The floating point conversion can't overflow, though it can and
 707  * does lose accuracy relative to the original fixed point value.
 708  * In practice this doesn't matter because png_fixed_point only
 709  * stores numbers with very low precision.  The png_ptr and s
 710  * arguments are unused by default but are there in case error
 711  * checking becomes a requirement.
 712  */
 713 #define png_float(png_ptr, fixed, s) (.00001 * (fixed))
 714 
 715 /* The fixed point conversion performs range checking and evaluates
 716  * its argument multiple times, so must be used with care.  The
 717  * range checking uses the PNG specification values for a signed
 718  * 32 bit fixed point value except that the values are deliberately
 719  * rounded-to-zero to an integral value - 21474 (21474.83 is roughly
 720  * (2^31-1) * 100000). 's' is a string that describes the value being
 721  * converted.
 722  *
 723  * NOTE: this macro will raise a png_error if the range check fails,
 724  * therefore it is normally only appropriate to use this on values
 725  * that come from API calls or other sources where an out of range
 726  * error indicates a programming error, not a data error!
 727  *
 728  * NOTE: by default this is off - the macro is not used - because the
 729  * function call saves a lot of code.
 730  */
 731 #ifdef PNG_FIXED_POINT_MACRO_SUPPORTED
 732 #define png_fixed(png_ptr, fp, s) ((fp) <= 21474 && (fp) >= -21474 ?\
 733     ((png_fixed_point)(100000 * (fp))) : (png_fixed_error(png_ptr, s),0))
 734 #endif
 735 /* else the corresponding function is defined below, inside the scope of the
 736  * cplusplus test.
 737  */
 738 #endif
 739 
 740 /* Constants for known chunk types.  If you need to add a chunk, define the name
 741  * here.  For historical reasons these constants have the form png_<name>; i.e.
 742  * the prefix is lower case.  Please use decimal values as the parameters to
 743  * match the ISO PNG specification and to avoid relying on the C locale
 744  * interpretation of character values.
 745  *
 746  * Prior to 1.5.6 these constants were strings, as of 1.5.6 png_uint_32 values
 747  * are computed and a new macro (PNG_STRING_FROM_CHUNK) added to allow a string
 748  * to be generated if required.
 749  *
 750  * PNG_32b correctly produces a value shifted by up to 24 bits, even on
 751  * architectures where (int) is only 16 bits.
 752  */
 753 #define PNG_32b(b,s) ((png_uint_32)(b) << (s))
 754 #define PNG_U32(b1,b2,b3,b4) \
 755    (PNG_32b(b1,24) | PNG_32b(b2,16) | PNG_32b(b3,8) | PNG_32b(b4,0))
 756 
 757 /* Constants for known chunk types.
 758  *
 759  * MAINTAINERS: If you need to add a chunk, define the name here.
 760  * For historical reasons these constants have the form png_<name>; i.e.
 761  * the prefix is lower case.  Please use decimal values as the parameters to
 762  * match the ISO PNG specification and to avoid relying on the C locale
 763  * interpretation of character values.  Please keep the list sorted.
 764  *
 765  * Notice that PNG_U32 is used to define a 32-bit value for the 4 byte chunk
 766  * type.  In fact the specification does not express chunk types this way,
 767  * however using a 32-bit value means that the chunk type can be read from the
 768  * stream using exactly the same code as used for a 32-bit unsigned value and
 769  * can be examined far more efficiently (using one arithmetic compare).
 770  *
 771  * Prior to 1.5.6 the chunk type constants were expressed as C strings.  The
 772  * libpng API still uses strings for 'unknown' chunks and a macro,
 773  * PNG_STRING_FROM_CHUNK, allows a string to be generated if required.  Notice
 774  * that for portable code numeric values must still be used; the string "IHDR"
 775  * is not portable and neither is PNG_U32('I', 'H', 'D', 'R').
 776  *
 777  * In 1.7.0 the definitions will be made public in png.h to avoid having to
 778  * duplicate the same definitions in application code.
 779  */
 780 #define png_IDAT PNG_U32( 73,  68,  65,  84)
 781 #define png_IEND PNG_U32( 73,  69,  78,  68)
 782 #define png_IHDR PNG_U32( 73,  72,  68,  82)
 783 #define png_PLTE PNG_U32( 80,  76,  84,  69)
 784 #define png_bKGD PNG_U32( 98,  75,  71,  68)
 785 #define png_cHRM PNG_U32( 99,  72,  82,  77)
 786 #define png_fRAc PNG_U32(102,  82,  65,  99) /* registered, not defined */
 787 #define png_gAMA PNG_U32(103,  65,  77,  65)
 788 #define png_gIFg PNG_U32(103,  73,  70, 103)
 789 #define png_gIFt PNG_U32(103,  73,  70, 116) /* deprecated */
 790 #define png_gIFx PNG_U32(103,  73,  70, 120)
 791 #define png_hIST PNG_U32(104,  73,  83,  84)
 792 #define png_iCCP PNG_U32(105,  67,  67,  80)
 793 #define png_iTXt PNG_U32(105,  84,  88, 116)
 794 #define png_oFFs PNG_U32(111,  70,  70, 115)
 795 #define png_pCAL PNG_U32(112,  67,  65,  76)
 796 #define png_pHYs PNG_U32(112,  72,  89, 115)
 797 #define png_sBIT PNG_U32(115,  66,  73,  84)
 798 #define png_sCAL PNG_U32(115,  67,  65,  76)
 799 #define png_sPLT PNG_U32(115,  80,  76,  84)
 800 #define png_sRGB PNG_U32(115,  82,  71,  66)
 801 #define png_sTER PNG_U32(115,  84,  69,  82)
 802 #define png_tEXt PNG_U32(116,  69,  88, 116)
 803 #define png_tIME PNG_U32(116,  73,  77,  69)
 804 #define png_tRNS PNG_U32(116,  82,  78,  83)
 805 #define png_zTXt PNG_U32(122,  84,  88, 116)
 806 
 807 /* The following will work on (signed char*) strings, whereas the get_uint_32
 808  * macro will fail on top-bit-set values because of the sign extension.
 809  */
 810 #define PNG_CHUNK_FROM_STRING(s)\
 811    PNG_U32(0xff&(s)[0], 0xff&(s)[1], 0xff&(s)[2], 0xff&(s)[3])
 812 
 813 /* This uses (char), not (png_byte) to avoid warnings on systems where (char) is
 814  * signed and the argument is a (char[])  This macro will fail miserably on
 815  * systems where (char) is more than 8 bits.
 816  */
 817 #define PNG_STRING_FROM_CHUNK(s,c)\
 818    (void)(((char*)(s))[0]=(char)((c)>>24), ((char*)(s))[1]=(char)((c)>>16),\
 819    ((char*)(s))[2]=(char)((c)>>8), ((char*)(s))[3]=(char)((c)))
 820 
 821 /* Do the same but terminate with a null character. */
 822 #define PNG_CSTRING_FROM_CHUNK(s,c)\
 823    (void)(PNG_STRING_FROM_CHUNK(s,c), ((char*)(s))[4] = 0)
 824 
 825 /* Test on flag values as defined in the spec (section 5.4): */
 826 #define PNG_CHUNK_ANCILLARY(c)   (1 & ((c) >> 29))
 827 #define PNG_CHUNK_CRITICAL(c)     (!PNG_CHUNK_ANCILLARY(c))
 828 #define PNG_CHUNK_PRIVATE(c)      (1 & ((c) >> 21))
 829 #define PNG_CHUNK_RESERVED(c)     (1 & ((c) >> 13))
 830 #define PNG_CHUNK_SAFE_TO_COPY(c) (1 & ((c) >>  5))
 831 
 832 /* Gamma values (new at libpng-1.5.4): */
 833 #define PNG_GAMMA_MAC_OLD 151724  /* Assume '1.8' is really 2.2/1.45! */
 834 #define PNG_GAMMA_MAC_INVERSE 65909
 835 #define PNG_GAMMA_sRGB_INVERSE 45455
 836 
 837 /* Almost everything below is C specific; the #defines above can be used in
 838  * non-C code (so long as it is C-preprocessed) the rest of this stuff cannot.
 839  */
 840 #ifndef PNG_VERSION_INFO_ONLY
 841 
 842 #include "pngstruct.h"
 843 #include "pnginfo.h"
 844 
 845 /* Validate the include paths - the include path used to generate pnglibconf.h
 846  * must match that used in the build, or we must be using pnglibconf.h.prebuilt:
 847  */
 848 #if PNG_ZLIB_VERNUM != 0 && PNG_ZLIB_VERNUM != ZLIB_VERNUM
 849 #  error ZLIB_VERNUM != PNG_ZLIB_VERNUM \
 850       "-I (include path) error: see the notes in pngpriv.h"
 851    /* This means that when pnglibconf.h was built the copy of zlib.h that it
 852     * used is not the same as the one being used here.  Because the build of
 853     * libpng makes decisions to use inflateInit2 and inflateReset2 based on the
 854     * zlib version number and because this affects handling of certain broken
 855     * PNG files the -I directives must match.
 856     *
 857     * The most likely explanation is that you passed a -I in CFLAGS. This will
 858     * not work; all the preprocessor directories and in particular all the -I
 859     * directives must be in CPPFLAGS.
 860     */
 861 #endif
 862 
 863 /* This is used for 16 bit gamma tables -- only the top level pointers are
 864  * const; this could be changed:
 865  */
 866 typedef const png_uint_16p * png_const_uint_16pp;
 867 
 868 /* Added to libpng-1.5.7: sRGB conversion tables */
 869 #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
 870    defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
 871 #ifdef PNG_SIMPLIFIED_READ_SUPPORTED
 872 PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_table, [256]);
 873    /* Convert from an sRGB encoded value 0..255 to a 16-bit linear value,
 874     * 0..65535.  This table gives the closest 16-bit answers (no errors).
 875     */
 876 #endif
 877 
 878 PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_base, [512]);
 879 PNG_INTERNAL_DATA(const png_byte, png_sRGB_delta, [512]);
 880 
 881 #define PNG_sRGB_FROM_LINEAR(linear) ((png_byte)((png_sRGB_base[(linear)>>15] +\
 882    ((((linear)&0x7fff)*png_sRGB_delta[(linear)>>15])>>12)) >> 8))
 883    /* Given a value 'linear' in the range 0..255*65535 calculate the 8-bit sRGB
 884     * encoded value with maximum error 0.646365.  Note that the input is not a
 885     * 16-bit value; it has been multiplied by 255! */
 886 #endif /* SIMPLIFIED_READ/WRITE */
 887 
 888 
 889 /* Inhibit C++ name-mangling for libpng functions but not for system calls. */
 890 #ifdef __cplusplus
 891 extern "C" {
 892 #endif /* __cplusplus */
 893 
 894 /* Internal functions; these are not exported from a DLL however because they
 895  * are used within several of the C source files they have to be C extern.
 896  *
 897  * All of these functions must be declared with PNG_INTERNAL_FUNCTION.
 898  */
 899 
 900 /* Zlib support */
 901 #define PNG_UNEXPECTED_ZLIB_RETURN (-7)
 902 PNG_INTERNAL_FUNCTION(void, png_zstream_error,(png_structrp png_ptr, int ret),
 903    PNG_EMPTY);
 904    /* Used by the zlib handling functions to ensure that z_stream::msg is always
 905     * set before they return.
 906     */
 907 
 908 #ifdef PNG_WRITE_SUPPORTED
 909 PNG_INTERNAL_FUNCTION(void,png_free_buffer_list,(png_structrp png_ptr,
 910    png_compression_bufferp *list),PNG_EMPTY);
 911    /* Free the buffer list used by the compressed write code. */
 912 #endif
 913 
 914 #if defined(PNG_FLOATING_POINT_SUPPORTED) && \
 915    !defined(PNG_FIXED_POINT_MACRO_SUPPORTED) && \
 916    (defined(PNG_gAMA_SUPPORTED) || defined(PNG_cHRM_SUPPORTED) || \
 917    defined(PNG_sCAL_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) || \
 918    defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)) || \
 919    (defined(PNG_sCAL_SUPPORTED) && \
 920    defined(PNG_FLOATING_ARITHMETIC_SUPPORTED))
 921 PNG_INTERNAL_FUNCTION(png_fixed_point,png_fixed,(png_const_structrp png_ptr,
 922    double fp, png_const_charp text),PNG_EMPTY);
 923 #endif
 924 
 925 /* Check the user version string for compatibility, returns false if the version
 926  * numbers aren't compatible.
 927  */
 928 PNG_INTERNAL_FUNCTION(int,png_user_version_check,(png_structrp png_ptr,
 929    png_const_charp user_png_ver),PNG_EMPTY);
 930 
 931 /* Internal base allocator - no messages, NULL on failure to allocate.  This
 932  * does, however, call the application provided allocator and that could call
 933  * png_error (although that would be a bug in the application implementation.)
 934  */
 935 PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_base,(png_const_structrp png_ptr,
 936    png_alloc_size_t size),PNG_ALLOCATED);
 937 
 938 #if defined(PNG_TEXT_SUPPORTED) || defined(PNG_sPLT_SUPPORTED) ||\
 939    defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED)
 940 /* Internal array allocator, outputs no error or warning messages on failure,
 941  * just returns NULL.
 942  */
 943 PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_array,(png_const_structrp png_ptr,
 944    int nelements, size_t element_size),PNG_ALLOCATED);
 945 
 946 /* The same but an existing array is extended by add_elements.  This function
 947  * also memsets the new elements to 0 and copies the old elements.  The old
 948  * array is not freed or altered.
 949  */
 950 PNG_INTERNAL_FUNCTION(png_voidp,png_realloc_array,(png_const_structrp png_ptr,
 951    png_const_voidp array, int old_elements, int add_elements,
 952    size_t element_size),PNG_ALLOCATED);
 953 #endif /* text, sPLT or unknown chunks */
 954 
 955 /* Magic to create a struct when there is no struct to call the user supplied
 956  * memory allocators.  Because error handling has not been set up the memory
 957  * handlers can't safely call png_error, but this is an obscure and undocumented
 958  * restriction so libpng has to assume that the 'free' handler, at least, might
 959  * call png_error.
 960  */
 961 PNG_INTERNAL_FUNCTION(png_structp,png_create_png_struct,
 962    (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
 963     png_error_ptr warn_fn, png_voidp mem_ptr, png_malloc_ptr malloc_fn,
 964     png_free_ptr free_fn),PNG_ALLOCATED);
 965 
 966 /* Free memory from internal libpng struct */
 967 PNG_INTERNAL_FUNCTION(void,png_destroy_png_struct,(png_structrp png_ptr),
 968    PNG_EMPTY);
 969 
 970 /* Free an allocated jmp_buf (always succeeds) */
 971 PNG_INTERNAL_FUNCTION(void,png_free_jmpbuf,(png_structrp png_ptr),PNG_EMPTY);
 972 
 973 /* Function to allocate memory for zlib.  PNGAPI is disallowed. */
 974 PNG_INTERNAL_FUNCTION(voidpf,png_zalloc,(voidpf png_ptr, uInt items, uInt size),
 975    PNG_ALLOCATED);
 976 
 977 /* Function to free memory for zlib.  PNGAPI is disallowed. */
 978 PNG_INTERNAL_FUNCTION(void,png_zfree,(voidpf png_ptr, voidpf ptr),PNG_EMPTY);
 979 
 980 /* Next four functions are used internally as callbacks.  PNGCBAPI is required
 981  * but not PNG_EXPORT.  PNGAPI added at libpng version 1.2.3, changed to
 982  * PNGCBAPI at 1.5.0
 983  */
 984 
 985 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_read_data,(png_structp png_ptr,
 986     png_bytep data, png_size_t length),PNG_EMPTY);
 987 
 988 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
 989 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_push_fill_buffer,(png_structp png_ptr,
 990     png_bytep buffer, png_size_t length),PNG_EMPTY);
 991 #endif
 992 
 993 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_write_data,(png_structp png_ptr,
 994     png_bytep data, png_size_t length),PNG_EMPTY);
 995 
 996 #ifdef PNG_WRITE_FLUSH_SUPPORTED
 997 #  ifdef PNG_STDIO_SUPPORTED
 998 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_flush,(png_structp png_ptr),
 999    PNG_EMPTY);
1000 #  endif
1001 #endif
1002 
1003 /* Reset the CRC variable */
1004 PNG_INTERNAL_FUNCTION(void,png_reset_crc,(png_structrp png_ptr),PNG_EMPTY);
1005 
1006 /* Write the "data" buffer to whatever output you are using */
1007 PNG_INTERNAL_FUNCTION(void,png_write_data,(png_structrp png_ptr,
1008     png_const_bytep data, png_size_t length),PNG_EMPTY);
1009 
1010 /* Read and check the PNG file signature */
1011 PNG_INTERNAL_FUNCTION(void,png_read_sig,(png_structrp png_ptr,
1012    png_inforp info_ptr),PNG_EMPTY);
1013 
1014 /* Read the chunk header (length + type name) */
1015 PNG_INTERNAL_FUNCTION(png_uint_32,png_read_chunk_header,(png_structrp png_ptr),
1016    PNG_EMPTY);
1017 
1018 /* Read data from whatever input you are using into the "data" buffer */
1019 PNG_INTERNAL_FUNCTION(void,png_read_data,(png_structrp png_ptr, png_bytep data,
1020     png_size_t length),PNG_EMPTY);
1021 
1022 /* Read bytes into buf, and update png_ptr->crc */
1023 PNG_INTERNAL_FUNCTION(void,png_crc_read,(png_structrp png_ptr, png_bytep buf,
1024     png_uint_32 length),PNG_EMPTY);
1025 
1026 /* Read "skip" bytes, read the file crc, and (optionally) verify png_ptr->crc */
1027 PNG_INTERNAL_FUNCTION(int,png_crc_finish,(png_structrp png_ptr,
1028    png_uint_32 skip),PNG_EMPTY);
1029 
1030 /* Read the CRC from the file and compare it to the libpng calculated CRC */
1031 PNG_INTERNAL_FUNCTION(int,png_crc_error,(png_structrp png_ptr),PNG_EMPTY);
1032 
1033 /* Calculate the CRC over a section of data.  Note that we are only
1034  * passing a maximum of 64K on systems that have this as a memory limit,
1035  * since this is the maximum buffer size we can specify.
1036  */
1037 PNG_INTERNAL_FUNCTION(void,png_calculate_crc,(png_structrp png_ptr,
1038    png_const_bytep ptr, png_size_t length),PNG_EMPTY);
1039 
1040 #ifdef PNG_WRITE_FLUSH_SUPPORTED
1041 PNG_INTERNAL_FUNCTION(void,png_flush,(png_structrp png_ptr),PNG_EMPTY);
1042 #endif
1043 
1044 /* Write various chunks */
1045 
1046 /* Write the IHDR chunk, and update the png_struct with the necessary
1047  * information.
1048  */
1049 PNG_INTERNAL_FUNCTION(void,png_write_IHDR,(png_structrp png_ptr,
1050    png_uint_32 width, png_uint_32 height, int bit_depth, int color_type,
1051    int compression_method, int filter_method, int interlace_method),PNG_EMPTY);
1052 
1053 PNG_INTERNAL_FUNCTION(void,png_write_PLTE,(png_structrp png_ptr,
1054    png_const_colorp palette, png_uint_32 num_pal),PNG_EMPTY);
1055 
1056 PNG_INTERNAL_FUNCTION(void,png_compress_IDAT,(png_structrp png_ptr,
1057    png_const_bytep row_data, png_alloc_size_t row_data_length, int flush),
1058    PNG_EMPTY);
1059 
1060 PNG_INTERNAL_FUNCTION(void,png_write_IEND,(png_structrp png_ptr),PNG_EMPTY);
1061 
1062 #ifdef PNG_WRITE_gAMA_SUPPORTED
1063 PNG_INTERNAL_FUNCTION(void,png_write_gAMA_fixed,(png_structrp png_ptr,
1064     png_fixed_point file_gamma),PNG_EMPTY);
1065 #endif
1066 
1067 #ifdef PNG_WRITE_sBIT_SUPPORTED
1068 PNG_INTERNAL_FUNCTION(void,png_write_sBIT,(png_structrp png_ptr,
1069     png_const_color_8p sbit, int color_type),PNG_EMPTY);
1070 #endif
1071 
1072 #ifdef PNG_WRITE_cHRM_SUPPORTED
1073 PNG_INTERNAL_FUNCTION(void,png_write_cHRM_fixed,(png_structrp png_ptr,
1074     const png_xy *xy), PNG_EMPTY);
1075     /* The xy value must have been previously validated */
1076 #endif
1077 
1078 #ifdef PNG_WRITE_sRGB_SUPPORTED
1079 PNG_INTERNAL_FUNCTION(void,png_write_sRGB,(png_structrp png_ptr,
1080     int intent),PNG_EMPTY);
1081 #endif
1082 
1083 #ifdef PNG_WRITE_iCCP_SUPPORTED
1084 PNG_INTERNAL_FUNCTION(void,png_write_iCCP,(png_structrp png_ptr,
1085    png_const_charp name, png_const_bytep profile), PNG_EMPTY);
1086    /* The profile must have been previously validated for correctness, the
1087     * length comes from the first four bytes.  Only the base, deflate,
1088     * compression is supported.
1089     */
1090 #endif
1091 
1092 #ifdef PNG_WRITE_sPLT_SUPPORTED
1093 PNG_INTERNAL_FUNCTION(void,png_write_sPLT,(png_structrp png_ptr,
1094     png_const_sPLT_tp palette),PNG_EMPTY);
1095 #endif
1096 
1097 #ifdef PNG_WRITE_tRNS_SUPPORTED
1098 PNG_INTERNAL_FUNCTION(void,png_write_tRNS,(png_structrp png_ptr,
1099     png_const_bytep trans, png_const_color_16p values, int number,
1100     int color_type),PNG_EMPTY);
1101 #endif
1102 
1103 #ifdef PNG_WRITE_bKGD_SUPPORTED
1104 PNG_INTERNAL_FUNCTION(void,png_write_bKGD,(png_structrp png_ptr,
1105     png_const_color_16p values, int color_type),PNG_EMPTY);
1106 #endif
1107 
1108 #ifdef PNG_WRITE_hIST_SUPPORTED
1109 PNG_INTERNAL_FUNCTION(void,png_write_hIST,(png_structrp png_ptr,
1110     png_const_uint_16p hist, int num_hist),PNG_EMPTY);
1111 #endif
1112 
1113 /* Chunks that have keywords */
1114 #ifdef PNG_WRITE_tEXt_SUPPORTED
1115 PNG_INTERNAL_FUNCTION(void,png_write_tEXt,(png_structrp png_ptr,
1116    png_const_charp key, png_const_charp text, png_size_t text_len),PNG_EMPTY);
1117 #endif
1118 
1119 #ifdef PNG_WRITE_zTXt_SUPPORTED
1120 PNG_INTERNAL_FUNCTION(void,png_write_zTXt,(png_structrp png_ptr, png_const_charp
1121     key, png_const_charp text, int compression),PNG_EMPTY);
1122 #endif
1123 
1124 #ifdef PNG_WRITE_iTXt_SUPPORTED
1125 PNG_INTERNAL_FUNCTION(void,png_write_iTXt,(png_structrp png_ptr,
1126     int compression, png_const_charp key, png_const_charp lang,
1127     png_const_charp lang_key, png_const_charp text),PNG_EMPTY);
1128 #endif
1129 
1130 #ifdef PNG_TEXT_SUPPORTED  /* Added at version 1.0.14 and 1.2.4 */
1131 PNG_INTERNAL_FUNCTION(int,png_set_text_2,(png_const_structrp png_ptr,
1132     png_inforp info_ptr, png_const_textp text_ptr, int num_text),PNG_EMPTY);
1133 #endif
1134 
1135 #ifdef PNG_WRITE_oFFs_SUPPORTED
1136 PNG_INTERNAL_FUNCTION(void,png_write_oFFs,(png_structrp png_ptr,
1137     png_int_32 x_offset, png_int_32 y_offset, int unit_type),PNG_EMPTY);
1138 #endif
1139 
1140 #ifdef PNG_WRITE_pCAL_SUPPORTED
1141 PNG_INTERNAL_FUNCTION(void,png_write_pCAL,(png_structrp png_ptr,
1142     png_charp purpose, png_int_32 X0, png_int_32 X1, int type, int nparams,
1143     png_const_charp units, png_charpp params),PNG_EMPTY);
1144 #endif
1145 
1146 #ifdef PNG_WRITE_pHYs_SUPPORTED
1147 PNG_INTERNAL_FUNCTION(void,png_write_pHYs,(png_structrp png_ptr,
1148     png_uint_32 x_pixels_per_unit, png_uint_32 y_pixels_per_unit,
1149     int unit_type),PNG_EMPTY);
1150 #endif
1151 
1152 #ifdef PNG_WRITE_tIME_SUPPORTED
1153 PNG_INTERNAL_FUNCTION(void,png_write_tIME,(png_structrp png_ptr,
1154     png_const_timep mod_time),PNG_EMPTY);
1155 #endif
1156 
1157 #ifdef PNG_WRITE_sCAL_SUPPORTED
1158 PNG_INTERNAL_FUNCTION(void,png_write_sCAL_s,(png_structrp png_ptr,
1159     int unit, png_const_charp width, png_const_charp height),PNG_EMPTY);
1160 #endif
1161 
1162 /* Called when finished processing a row of data */
1163 PNG_INTERNAL_FUNCTION(void,png_write_finish_row,(png_structrp png_ptr),
1164     PNG_EMPTY);
1165 
1166 /* Internal use only.   Called before first row of data */
1167 PNG_INTERNAL_FUNCTION(void,png_write_start_row,(png_structrp png_ptr),
1168     PNG_EMPTY);
1169 
1170 /* Combine a row of data, dealing with alpha, etc. if requested.  'row' is an
1171  * array of png_ptr->width pixels.  If the image is not interlaced or this
1172  * is the final pass this just does a memcpy, otherwise the "display" flag
1173  * is used to determine whether to copy pixels that are not in the current pass.
1174  *
1175  * Because 'png_do_read_interlace' (below) replicates pixels this allows this
1176  * function to achieve the documented 'blocky' appearance during interlaced read
1177  * if display is 1 and the 'sparkle' appearance, where existing pixels in 'row'
1178  * are not changed if they are not in the current pass, when display is 0.
1179  *
1180  * 'display' must be 0 or 1, otherwise the memcpy will be done regardless.
1181  *
1182  * The API always reads from the png_struct row buffer and always assumes that
1183  * it is full width (png_do_read_interlace has already been called.)
1184  *
1185  * This function is only ever used to write to row buffers provided by the
1186  * caller of the relevant libpng API and the row must have already been
1187  * transformed by the read transformations.
1188  *
1189  * The PNG_USE_COMPILE_TIME_MASKS option causes generation of pre-computed
1190  * bitmasks for use within the code, otherwise runtime generated masks are used.
1191  * The default is compile time masks.
1192  */
1193 #ifndef PNG_USE_COMPILE_TIME_MASKS
1194 #  define PNG_USE_COMPILE_TIME_MASKS 1
1195 #endif
1196 PNG_INTERNAL_FUNCTION(void,png_combine_row,(png_const_structrp png_ptr,
1197     png_bytep row, int display),PNG_EMPTY);
1198 
1199 #ifdef PNG_READ_INTERLACING_SUPPORTED
1200 /* Expand an interlaced row: the 'row_info' describes the pass data that has
1201  * been read in and must correspond to the pixels in 'row', the pixels are
1202  * expanded (moved apart) in 'row' to match the final layout, when doing this
1203  * the pixels are *replicated* to the intervening space.  This is essential for
1204  * the correct operation of png_combine_row, above.
1205  */
1206 PNG_INTERNAL_FUNCTION(void,png_do_read_interlace,(png_row_infop row_info,
1207     png_bytep row, int pass, png_uint_32 transformations),PNG_EMPTY);
1208 #endif
1209 
1210 /* GRR TO DO (2.0 or whenever):  simplify other internal calling interfaces */
1211 
1212 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1213 /* Grab pixels out of a row for an interlaced pass */
1214 PNG_INTERNAL_FUNCTION(void,png_do_write_interlace,(png_row_infop row_info,
1215     png_bytep row, int pass),PNG_EMPTY);
1216 #endif
1217 
1218 /* Unfilter a row: check the filter value before calling this, there is no point
1219  * calling it for PNG_FILTER_VALUE_NONE.
1220  */
1221 PNG_INTERNAL_FUNCTION(void,png_read_filter_row,(png_structrp pp, png_row_infop
1222     row_info, png_bytep row, png_const_bytep prev_row, int filter),PNG_EMPTY);
1223 
1224 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_up_neon,(png_row_infop row_info,
1225     png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1226 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_neon,(png_row_infop
1227     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1228 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_neon,(png_row_infop
1229     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1230 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_neon,(png_row_infop
1231     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1232 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_neon,(png_row_infop
1233     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1234 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_neon,(png_row_infop
1235     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1236 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_neon,(png_row_infop
1237     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1238 
1239 /* Choose the best filter to use and filter the row data */
1240 PNG_INTERNAL_FUNCTION(void,png_write_find_filter,(png_structrp png_ptr,
1241     png_row_infop row_info),PNG_EMPTY);
1242 
1243 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1244 PNG_INTERNAL_FUNCTION(void,png_read_IDAT_data,(png_structrp png_ptr,
1245    png_bytep output, png_alloc_size_t avail_out),PNG_EMPTY);
1246    /* Read 'avail_out' bytes of data from the IDAT stream.  If the output buffer
1247     * is NULL the function checks, instead, for the end of the stream.  In this
1248     * case a benign error will be issued if the stream end is not found or if
1249     * extra data has to be consumed.
1250     */
1251 PNG_INTERNAL_FUNCTION(void,png_read_finish_IDAT,(png_structrp png_ptr),
1252    PNG_EMPTY);
1253    /* This cleans up when the IDAT LZ stream does not end when the last image
1254     * byte is read; there is still some pending input.
1255     */
1256 
1257 PNG_INTERNAL_FUNCTION(void,png_read_finish_row,(png_structrp png_ptr),
1258    PNG_EMPTY);
1259    /* Finish a row while reading, dealing with interlacing passes, etc. */
1260 #endif /* SEQUENTIAL_READ */
1261 
1262 /* Initialize the row buffers, etc. */
1263 PNG_INTERNAL_FUNCTION(void,png_read_start_row,(png_structrp png_ptr),PNG_EMPTY);
1264 
1265 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1266 /* Optional call to update the users info structure */
1267 PNG_INTERNAL_FUNCTION(void,png_read_transform_info,(png_structrp png_ptr,
1268     png_inforp info_ptr),PNG_EMPTY);
1269 #endif
1270 
1271 /* Shared transform functions, defined in pngtran.c */
1272 #if defined(PNG_WRITE_FILLER_SUPPORTED) || \
1273     defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
1274 PNG_INTERNAL_FUNCTION(void,png_do_strip_channel,(png_row_infop row_info,
1275     png_bytep row, int at_start),PNG_EMPTY);
1276 #endif
1277 
1278 #ifdef PNG_16BIT_SUPPORTED
1279 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
1280 PNG_INTERNAL_FUNCTION(void,png_do_swap,(png_row_infop row_info,
1281     png_bytep row),PNG_EMPTY);
1282 #endif
1283 #endif
1284 
1285 #if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
1286     defined(PNG_WRITE_PACKSWAP_SUPPORTED)
1287 PNG_INTERNAL_FUNCTION(void,png_do_packswap,(png_row_infop row_info,
1288     png_bytep row),PNG_EMPTY);
1289 #endif
1290 
1291 #if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
1292 PNG_INTERNAL_FUNCTION(void,png_do_invert,(png_row_infop row_info,
1293     png_bytep row),PNG_EMPTY);
1294 #endif
1295 
1296 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
1297 PNG_INTERNAL_FUNCTION(void,png_do_bgr,(png_row_infop row_info,
1298     png_bytep row),PNG_EMPTY);
1299 #endif
1300 
1301 /* The following decodes the appropriate chunks, and does error correction,
1302  * then calls the appropriate callback for the chunk if it is valid.
1303  */
1304 
1305 /* Decode the IHDR chunk */
1306 PNG_INTERNAL_FUNCTION(void,png_handle_IHDR,(png_structrp png_ptr,
1307     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1308 PNG_INTERNAL_FUNCTION(void,png_handle_PLTE,(png_structrp png_ptr,
1309     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1310 PNG_INTERNAL_FUNCTION(void,png_handle_IEND,(png_structrp png_ptr,
1311     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1312 
1313 #ifdef PNG_READ_bKGD_SUPPORTED
1314 PNG_INTERNAL_FUNCTION(void,png_handle_bKGD,(png_structrp png_ptr,
1315     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1316 #endif
1317 
1318 #ifdef PNG_READ_cHRM_SUPPORTED
1319 PNG_INTERNAL_FUNCTION(void,png_handle_cHRM,(png_structrp png_ptr,
1320     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1321 #endif
1322 
1323 #ifdef PNG_READ_gAMA_SUPPORTED
1324 PNG_INTERNAL_FUNCTION(void,png_handle_gAMA,(png_structrp png_ptr,
1325     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1326 #endif
1327 
1328 #ifdef PNG_READ_hIST_SUPPORTED
1329 PNG_INTERNAL_FUNCTION(void,png_handle_hIST,(png_structrp png_ptr,
1330     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1331 #endif
1332 
1333 #ifdef PNG_READ_iCCP_SUPPORTED
1334 PNG_INTERNAL_FUNCTION(void,png_handle_iCCP,(png_structrp png_ptr,
1335     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1336 #endif /* READ_iCCP */
1337 
1338 #ifdef PNG_READ_iTXt_SUPPORTED
1339 PNG_INTERNAL_FUNCTION(void,png_handle_iTXt,(png_structrp png_ptr,
1340     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1341 #endif
1342 
1343 #ifdef PNG_READ_oFFs_SUPPORTED
1344 PNG_INTERNAL_FUNCTION(void,png_handle_oFFs,(png_structrp png_ptr,
1345     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1346 #endif
1347 
1348 #ifdef PNG_READ_pCAL_SUPPORTED
1349 PNG_INTERNAL_FUNCTION(void,png_handle_pCAL,(png_structrp png_ptr,
1350     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1351 #endif
1352 
1353 #ifdef PNG_READ_pHYs_SUPPORTED
1354 PNG_INTERNAL_FUNCTION(void,png_handle_pHYs,(png_structrp png_ptr,
1355     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1356 #endif
1357 
1358 #ifdef PNG_READ_sBIT_SUPPORTED
1359 PNG_INTERNAL_FUNCTION(void,png_handle_sBIT,(png_structrp png_ptr,
1360     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1361 #endif
1362 
1363 #ifdef PNG_READ_sCAL_SUPPORTED
1364 PNG_INTERNAL_FUNCTION(void,png_handle_sCAL,(png_structrp png_ptr,
1365     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1366 #endif
1367 
1368 #ifdef PNG_READ_sPLT_SUPPORTED
1369 PNG_INTERNAL_FUNCTION(void,png_handle_sPLT,(png_structrp png_ptr,
1370     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1371 #endif /* READ_sPLT */
1372 
1373 #ifdef PNG_READ_sRGB_SUPPORTED
1374 PNG_INTERNAL_FUNCTION(void,png_handle_sRGB,(png_structrp png_ptr,
1375     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1376 #endif
1377 
1378 #ifdef PNG_READ_tEXt_SUPPORTED
1379 PNG_INTERNAL_FUNCTION(void,png_handle_tEXt,(png_structrp png_ptr,
1380     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1381 #endif
1382 
1383 #ifdef PNG_READ_tIME_SUPPORTED
1384 PNG_INTERNAL_FUNCTION(void,png_handle_tIME,(png_structrp png_ptr,
1385     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1386 #endif
1387 
1388 #ifdef PNG_READ_tRNS_SUPPORTED
1389 PNG_INTERNAL_FUNCTION(void,png_handle_tRNS,(png_structrp png_ptr,
1390     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1391 #endif
1392 
1393 #ifdef PNG_READ_zTXt_SUPPORTED
1394 PNG_INTERNAL_FUNCTION(void,png_handle_zTXt,(png_structrp png_ptr,
1395     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1396 #endif
1397 
1398 PNG_INTERNAL_FUNCTION(void,png_check_chunk_name,(png_structrp png_ptr,
1399     png_uint_32 chunk_name),PNG_EMPTY);
1400 
1401 PNG_INTERNAL_FUNCTION(void,png_handle_unknown,(png_structrp png_ptr,
1402     png_inforp info_ptr, png_uint_32 length, int keep),PNG_EMPTY);
1403    /* This is the function that gets called for unknown chunks.  The 'keep'
1404     * argument is either non-zero for a known chunk that has been set to be
1405     * handled as unknown or zero for an unknown chunk.  By default the function
1406     * just skips the chunk or errors out if it is critical.
1407     */
1408 
1409 #if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) ||\
1410     defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
1411 PNG_INTERNAL_FUNCTION(int,png_chunk_unknown_handling,
1412     (png_const_structrp png_ptr, png_uint_32 chunk_name),PNG_EMPTY);
1413    /* Exactly as the API png_handle_as_unknown() except that the argument is a
1414     * 32-bit chunk name, not a string.
1415     */
1416 #endif /* READ_UNKNOWN_CHUNKS || HANDLE_AS_UNKNOWN */
1417 
1418 /* Handle the transformations for reading and writing */
1419 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1420 PNG_INTERNAL_FUNCTION(void,png_do_read_transformations,(png_structrp png_ptr,
1421    png_row_infop row_info),PNG_EMPTY);
1422 #endif
1423 #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
1424 PNG_INTERNAL_FUNCTION(void,png_do_write_transformations,(png_structrp png_ptr,
1425    png_row_infop row_info),PNG_EMPTY);
1426 #endif
1427 
1428 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1429 PNG_INTERNAL_FUNCTION(void,png_init_read_transformations,(png_structrp png_ptr),
1430     PNG_EMPTY);
1431 #endif
1432 
1433 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1434 PNG_INTERNAL_FUNCTION(void,png_push_read_chunk,(png_structrp png_ptr,
1435     png_inforp info_ptr),PNG_EMPTY);
1436 PNG_INTERNAL_FUNCTION(void,png_push_read_sig,(png_structrp png_ptr,
1437     png_inforp info_ptr),PNG_EMPTY);
1438 PNG_INTERNAL_FUNCTION(void,png_push_check_crc,(png_structrp png_ptr),PNG_EMPTY);
1439 PNG_INTERNAL_FUNCTION(void,png_push_crc_skip,(png_structrp png_ptr,
1440     png_uint_32 length),PNG_EMPTY);
1441 PNG_INTERNAL_FUNCTION(void,png_push_crc_finish,(png_structrp png_ptr),
1442     PNG_EMPTY);
1443 PNG_INTERNAL_FUNCTION(void,png_push_save_buffer,(png_structrp png_ptr),
1444     PNG_EMPTY);
1445 PNG_INTERNAL_FUNCTION(void,png_push_restore_buffer,(png_structrp png_ptr,
1446     png_bytep buffer, png_size_t buffer_length),PNG_EMPTY);
1447 PNG_INTERNAL_FUNCTION(void,png_push_read_IDAT,(png_structrp png_ptr),PNG_EMPTY);
1448 PNG_INTERNAL_FUNCTION(void,png_process_IDAT_data,(png_structrp png_ptr,
1449     png_bytep buffer, png_size_t buffer_length),PNG_EMPTY);
1450 PNG_INTERNAL_FUNCTION(void,png_push_process_row,(png_structrp png_ptr),
1451     PNG_EMPTY);
1452 PNG_INTERNAL_FUNCTION(void,png_push_handle_unknown,(png_structrp png_ptr,
1453    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1454 PNG_INTERNAL_FUNCTION(void,png_push_have_info,(png_structrp png_ptr,
1455    png_inforp info_ptr),PNG_EMPTY);
1456 PNG_INTERNAL_FUNCTION(void,png_push_have_end,(png_structrp png_ptr,
1457    png_inforp info_ptr),PNG_EMPTY);
1458 PNG_INTERNAL_FUNCTION(void,png_push_have_row,(png_structrp png_ptr,
1459      png_bytep row),PNG_EMPTY);
1460 PNG_INTERNAL_FUNCTION(void,png_push_read_end,(png_structrp png_ptr,
1461     png_inforp info_ptr),PNG_EMPTY);
1462 PNG_INTERNAL_FUNCTION(void,png_process_some_data,(png_structrp png_ptr,
1463     png_inforp info_ptr),PNG_EMPTY);
1464 PNG_INTERNAL_FUNCTION(void,png_read_push_finish_row,(png_structrp png_ptr),
1465     PNG_EMPTY);
1466 #  ifdef PNG_READ_tEXt_SUPPORTED
1467 PNG_INTERNAL_FUNCTION(void,png_push_handle_tEXt,(png_structrp png_ptr,
1468     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1469 PNG_INTERNAL_FUNCTION(void,png_push_read_tEXt,(png_structrp png_ptr,
1470     png_inforp info_ptr),PNG_EMPTY);
1471 #  endif
1472 #  ifdef PNG_READ_zTXt_SUPPORTED
1473 PNG_INTERNAL_FUNCTION(void,png_push_handle_zTXt,(png_structrp png_ptr,
1474     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1475 PNG_INTERNAL_FUNCTION(void,png_push_read_zTXt,(png_structrp png_ptr,
1476     png_inforp info_ptr),PNG_EMPTY);
1477 #  endif
1478 #  ifdef PNG_READ_iTXt_SUPPORTED
1479 PNG_INTERNAL_FUNCTION(void,png_push_handle_iTXt,(png_structrp png_ptr,
1480     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1481 PNG_INTERNAL_FUNCTION(void,png_push_read_iTXt,(png_structrp png_ptr,
1482     png_inforp info_ptr),PNG_EMPTY);
1483 #  endif
1484 
1485 #endif /* PROGRESSIVE_READ */
1486 
1487 /* Added at libpng version 1.6.0 */
1488 #ifdef PNG_GAMMA_SUPPORTED
1489 PNG_INTERNAL_FUNCTION(void,png_colorspace_set_gamma,(png_const_structrp png_ptr,
1490     png_colorspacerp colorspace, png_fixed_point gAMA), PNG_EMPTY);
1491    /* Set the colorspace gamma with a value provided by the application or by
1492     * the gAMA chunk on read.  The value will override anything set by an ICC
1493     * profile.
1494     */
1495 
1496 PNG_INTERNAL_FUNCTION(void,png_colorspace_sync_info,(png_const_structrp png_ptr,
1497     png_inforp info_ptr), PNG_EMPTY);
1498     /* Synchronize the info 'valid' flags with the colorspace */
1499 
1500 PNG_INTERNAL_FUNCTION(void,png_colorspace_sync,(png_const_structrp png_ptr,
1501     png_inforp info_ptr), PNG_EMPTY);
1502     /* Copy the png_struct colorspace to the info_struct and call the above to
1503      * synchronize the flags.  Checks for NULL info_ptr and does nothing.
1504      */
1505 #endif
1506 
1507 /* Added at libpng version 1.4.0 */
1508 #ifdef PNG_COLORSPACE_SUPPORTED
1509 /* These internal functions are for maintaining the colorspace structure within
1510  * a png_info or png_struct (or, indeed, both).
1511  */
1512 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_chromaticities,
1513    (png_const_structrp png_ptr, png_colorspacerp colorspace, const png_xy *xy,
1514     int preferred), PNG_EMPTY);
1515 
1516 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_endpoints,
1517    (png_const_structrp png_ptr, png_colorspacerp colorspace, const png_XYZ *XYZ,
1518     int preferred), PNG_EMPTY);
1519 
1520 #ifdef PNG_sRGB_SUPPORTED
1521 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_sRGB,(png_const_structrp png_ptr,
1522    png_colorspacerp colorspace, int intent), PNG_EMPTY);
1523    /* This does set the colorspace gAMA and cHRM values too, but doesn't set the
1524     * flags to write them, if it returns false there was a problem and an error
1525     * message has already been output (but the colorspace may still need to be
1526     * synced to record the invalid flag).
1527     */
1528 #endif /* sRGB */
1529 
1530 #ifdef PNG_iCCP_SUPPORTED
1531 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_ICC,(png_const_structrp png_ptr,
1532    png_colorspacerp colorspace, png_const_charp name,
1533    png_uint_32 profile_length, png_const_bytep profile, int color_type),
1534    PNG_EMPTY);
1535    /* The 'name' is used for information only */
1536 
1537 /* Routines for checking parts of an ICC profile. */
1538 PNG_INTERNAL_FUNCTION(int,png_icc_check_length,(png_const_structrp png_ptr,
1539    png_colorspacerp colorspace, png_const_charp name,
1540    png_uint_32 profile_length), PNG_EMPTY);
1541 PNG_INTERNAL_FUNCTION(int,png_icc_check_header,(png_const_structrp png_ptr,
1542    png_colorspacerp colorspace, png_const_charp name,
1543    png_uint_32 profile_length,
1544    png_const_bytep profile /* first 132 bytes only */, int color_type),
1545    PNG_EMPTY);
1546 PNG_INTERNAL_FUNCTION(int,png_icc_check_tag_table,(png_const_structrp png_ptr,
1547    png_colorspacerp colorspace, png_const_charp name,
1548    png_uint_32 profile_length,
1549    png_const_bytep profile /* header plus whole tag table */), PNG_EMPTY);
1550 #ifdef PNG_sRGB_SUPPORTED
1551 PNG_INTERNAL_FUNCTION(void,png_icc_set_sRGB,(
1552    png_const_structrp png_ptr, png_colorspacerp colorspace,
1553    png_const_bytep profile, uLong adler), PNG_EMPTY);
1554    /* 'adler' is the Adler32 checksum of the uncompressed profile data. It may
1555     * be zero to indicate that it is not available.  It is used, if provided,
1556     * as a fast check on the profile when checking to see if it is sRGB.
1557     */
1558 #endif
1559 #endif /* iCCP */
1560 
1561 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1562 PNG_INTERNAL_FUNCTION(void,png_colorspace_set_rgb_coefficients,
1563    (png_structrp png_ptr), PNG_EMPTY);
1564    /* Set the rgb_to_gray coefficients from the colorspace Y values */
1565 #endif /* READ_RGB_TO_GRAY */
1566 #endif /* COLORSPACE */
1567 
1568 /* Added at libpng version 1.4.0 */
1569 PNG_INTERNAL_FUNCTION(void,png_check_IHDR,(png_const_structrp png_ptr,
1570     png_uint_32 width, png_uint_32 height, int bit_depth,
1571     int color_type, int interlace_type, int compression_type,
1572     int filter_type),PNG_EMPTY);
1573 
1574 /* Added at libpng version 1.5.10 */
1575 #if defined(PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED) || \
1576     defined(PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED)
1577 PNG_INTERNAL_FUNCTION(void,png_do_check_palette_indexes,
1578    (png_structrp png_ptr, png_row_infop row_info),PNG_EMPTY);
1579 #endif
1580 
1581 #if defined(PNG_FLOATING_POINT_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED)
1582 PNG_INTERNAL_FUNCTION(void,png_fixed_error,(png_const_structrp png_ptr,
1583    png_const_charp name),PNG_NORETURN);
1584 #endif
1585 
1586 /* Puts 'string' into 'buffer' at buffer[pos], taking care never to overwrite
1587  * the end.  Always leaves the buffer nul terminated.  Never errors out (and
1588  * there is no error code.)
1589  */
1590 PNG_INTERNAL_FUNCTION(size_t,png_safecat,(png_charp buffer, size_t bufsize,
1591    size_t pos, png_const_charp string),PNG_EMPTY);
1592 
1593 /* Various internal functions to handle formatted warning messages, currently
1594  * only implemented for warnings.
1595  */
1596 #if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_TIME_RFC1123_SUPPORTED)
1597 /* Utility to dump an unsigned value into a buffer, given a start pointer and
1598  * and end pointer (which should point just *beyond* the end of the buffer!)
1599  * Returns the pointer to the start of the formatted string.  This utility only
1600  * does unsigned values.
1601  */
1602 PNG_INTERNAL_FUNCTION(png_charp,png_format_number,(png_const_charp start,
1603    png_charp end, int format, png_alloc_size_t number),PNG_EMPTY);
1604 
1605 /* Convenience macro that takes an array: */
1606 #define PNG_FORMAT_NUMBER(buffer,format,number) \
1607    png_format_number(buffer, buffer + (sizeof buffer), format, number)
1608 
1609 /* Suggested size for a number buffer (enough for 64 bits and a sign!) */
1610 #define PNG_NUMBER_BUFFER_SIZE 24
1611 
1612 /* These are the integer formats currently supported, the name is formed from
1613  * the standard printf(3) format string.
1614  */
1615 #define PNG_NUMBER_FORMAT_u     1 /* chose unsigned API! */
1616 #define PNG_NUMBER_FORMAT_02u   2
1617 #define PNG_NUMBER_FORMAT_d     1 /* chose signed API! */
1618 #define PNG_NUMBER_FORMAT_02d   2
1619 #define PNG_NUMBER_FORMAT_x     3
1620 #define PNG_NUMBER_FORMAT_02x   4
1621 #define PNG_NUMBER_FORMAT_fixed 5 /* choose the signed API */
1622 #endif
1623 
1624 #ifdef PNG_WARNINGS_SUPPORTED
1625 /* New defines and members adding in libpng-1.5.4 */
1626 #  define PNG_WARNING_PARAMETER_SIZE 32
1627 #  define PNG_WARNING_PARAMETER_COUNT 8 /* Maximum 9; see pngerror.c */
1628 
1629 /* An l-value of this type has to be passed to the APIs below to cache the
1630  * values of the parameters to a formatted warning message.
1631  */
1632 typedef char png_warning_parameters[PNG_WARNING_PARAMETER_COUNT][
1633    PNG_WARNING_PARAMETER_SIZE];
1634 
1635 PNG_INTERNAL_FUNCTION(void,png_warning_parameter,(png_warning_parameters p,
1636    int number, png_const_charp string),PNG_EMPTY);
1637    /* Parameters are limited in size to PNG_WARNING_PARAMETER_SIZE characters,
1638     * including the trailing '\0'.
1639     */
1640 PNG_INTERNAL_FUNCTION(void,png_warning_parameter_unsigned,
1641    (png_warning_parameters p, int number, int format, png_alloc_size_t value),
1642    PNG_EMPTY);
1643    /* Use png_alloc_size_t because it is an unsigned type as big as any we
1644     * need to output.  Use the following for a signed value.
1645     */
1646 PNG_INTERNAL_FUNCTION(void,png_warning_parameter_signed,
1647    (png_warning_parameters p, int number, int format, png_int_32 value),
1648    PNG_EMPTY);
1649 
1650 PNG_INTERNAL_FUNCTION(void,png_formatted_warning,(png_const_structrp png_ptr,
1651    png_warning_parameters p, png_const_charp message),PNG_EMPTY);
1652    /* 'message' follows the X/Open approach of using @1, @2 to insert
1653     * parameters previously supplied using the above functions.  Errors in
1654     * specifying the parameters will simply result in garbage substitutions.
1655     */
1656 #endif
1657 
1658 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
1659 /* Application errors (new in 1.6); use these functions (declared below) for
1660  * errors in the parameters or order of API function calls on read.  The
1661  * 'warning' should be used for an error that can be handled completely; the
1662  * 'error' for one which can be handled safely but which may lose application
1663  * information or settings.
1664  *
1665  * By default these both result in a png_error call prior to release, while in a
1666  * released version the 'warning' is just a warning.  However if the application
1667  * explicitly disables benign errors (explicitly permitting the code to lose
1668  * information) they both turn into warnings.
1669  *
1670  * If benign errors aren't supported they end up as the corresponding base call
1671  * (png_warning or png_error.)
1672  */
1673 PNG_INTERNAL_FUNCTION(void,png_app_warning,(png_const_structrp png_ptr,
1674    png_const_charp message),PNG_EMPTY);
1675    /* The application provided invalid parameters to an API function or called
1676     * an API function at the wrong time, libpng can completely recover.
1677     */
1678 
1679 PNG_INTERNAL_FUNCTION(void,png_app_error,(png_const_structrp png_ptr,
1680    png_const_charp message),PNG_EMPTY);
1681    /* As above but libpng will ignore the call, or attempt some other partial
1682     * recovery from the error.
1683     */
1684 #else
1685 #  define png_app_warning(pp,s) png_warning(pp,s)
1686 #  define png_app_error(pp,s) png_error(pp,s)
1687 #endif
1688 
1689 PNG_INTERNAL_FUNCTION(void,png_chunk_report,(png_const_structrp png_ptr,
1690    png_const_charp message, int error),PNG_EMPTY);
1691    /* Report a recoverable issue in chunk data.  On read this is used to report
1692     * a problem found while reading a particular chunk and the
1693     * png_chunk_benign_error or png_chunk_warning function is used as
1694     * appropriate.  On write this is used to report an error that comes from
1695     * data set via an application call to a png_set_ API and png_app_error or
1696     * png_app_warning is used as appropriate.
1697     *
1698     * The 'error' parameter must have one of the following values:
1699     */
1700 #define PNG_CHUNK_WARNING     0 /* never an error */
1701 #define PNG_CHUNK_WRITE_ERROR 1 /* an error only on write */
1702 #define PNG_CHUNK_ERROR       2 /* always an error */
1703 
1704 /* ASCII to FP interfaces, currently only implemented if sCAL
1705  * support is required.
1706  */
1707 #if defined(PNG_sCAL_SUPPORTED)
1708 /* MAX_DIGITS is actually the maximum number of characters in an sCAL
1709  * width or height, derived from the precision (number of significant
1710  * digits - a build time settable option) and assumptions about the
1711  * maximum ridiculous exponent.
1712  */
1713 #define PNG_sCAL_MAX_DIGITS (PNG_sCAL_PRECISION+1/*.*/+1/*E*/+10/*exponent*/)
1714 
1715 #ifdef PNG_FLOATING_POINT_SUPPORTED
1716 PNG_INTERNAL_FUNCTION(void,png_ascii_from_fp,(png_const_structrp png_ptr,
1717    png_charp ascii, png_size_t size, double fp, unsigned int precision),
1718    PNG_EMPTY);
1719 #endif /* FLOATING_POINT */
1720 
1721 #ifdef PNG_FIXED_POINT_SUPPORTED
1722 PNG_INTERNAL_FUNCTION(void,png_ascii_from_fixed,(png_const_structrp png_ptr,
1723    png_charp ascii, png_size_t size, png_fixed_point fp),PNG_EMPTY);
1724 #endif /* FIXED_POINT */
1725 #endif /* sCAL */
1726 
1727 #if defined(PNG_sCAL_SUPPORTED) || defined(PNG_pCAL_SUPPORTED)
1728 /* An internal API to validate the format of a floating point number.
1729  * The result is the index of the next character.  If the number is
1730  * not valid it will be the index of a character in the supposed number.
1731  *
1732  * The format of a number is defined in the PNG extensions specification
1733  * and this API is strictly conformant to that spec, not anyone elses!
1734  *
1735  * The format as a regular expression is:
1736  *
1737  * [+-]?[0-9]+.?([Ee][+-]?[0-9]+)?
1738  *
1739  * or:
1740  *
1741  * [+-]?.[0-9]+(.[0-9]+)?([Ee][+-]?[0-9]+)?
1742  *
1743  * The complexity is that either integer or fraction must be present and the
1744  * fraction is permitted to have no digits only if the integer is present.
1745  *
1746  * NOTE: The dangling E problem.
1747  *   There is a PNG valid floating point number in the following:
1748  *
1749  *       PNG floating point numbers are not greedy.
1750  *
1751  *   Working this out requires *TWO* character lookahead (because of the
1752  *   sign), the parser does not do this - it will fail at the 'r' - this
1753  *   doesn't matter for PNG sCAL chunk values, but it requires more care
1754  *   if the value were ever to be embedded in something more complex.  Use
1755  *   ANSI-C strtod if you need the lookahead.
1756  */
1757 /* State table for the parser. */
1758 #define PNG_FP_INTEGER    0  /* before or in integer */
1759 #define PNG_FP_FRACTION   1  /* before or in fraction */
1760 #define PNG_FP_EXPONENT   2  /* before or in exponent */
1761 #define PNG_FP_STATE      3  /* mask for the above */
1762 #define PNG_FP_SAW_SIGN   4  /* Saw +/- in current state */
1763 #define PNG_FP_SAW_DIGIT  8  /* Saw a digit in current state */
1764 #define PNG_FP_SAW_DOT   16  /* Saw a dot in current state */
1765 #define PNG_FP_SAW_E     32  /* Saw an E (or e) in current state */
1766 #define PNG_FP_SAW_ANY   60  /* Saw any of the above 4 */
1767 
1768 /* These three values don't affect the parser.  They are set but not used.
1769  */
1770 #define PNG_FP_WAS_VALID 64  /* Preceding substring is a valid fp number */
1771 #define PNG_FP_NEGATIVE 128  /* A negative number, including "-0" */
1772 #define PNG_FP_NONZERO  256  /* A non-zero value */
1773 #define PNG_FP_STICKY   448  /* The above three flags */
1774 
1775 /* This is available for the caller to store in 'state' if required.  Do not
1776  * call the parser after setting it (the parser sometimes clears it.)
1777  */
1778 #define PNG_FP_INVALID  512  /* Available for callers as a distinct value */
1779 
1780 /* Result codes for the parser (boolean - true meants ok, false means
1781  * not ok yet.)
1782  */
1783 #define PNG_FP_MAYBE      0  /* The number may be valid in the future */
1784 #define PNG_FP_OK         1  /* The number is valid */
1785 
1786 /* Tests on the sticky non-zero and negative flags.  To pass these checks
1787  * the state must also indicate that the whole number is valid - this is
1788  * achieved by testing PNG_FP_SAW_DIGIT (see the implementation for why this
1789  * is equivalent to PNG_FP_OK above.)
1790  */
1791 #define PNG_FP_NZ_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NEGATIVE | PNG_FP_NONZERO)
1792    /* NZ_MASK: the string is valid and a non-zero negative value */
1793 #define PNG_FP_Z_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NONZERO)
1794    /* Z MASK: the string is valid and a non-zero value. */
1795    /* PNG_FP_SAW_DIGIT: the string is valid. */
1796 #define PNG_FP_IS_ZERO(state) (((state) & PNG_FP_Z_MASK) == PNG_FP_SAW_DIGIT)
1797 #define PNG_FP_IS_POSITIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_Z_MASK)
1798 #define PNG_FP_IS_NEGATIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_NZ_MASK)
1799 
1800 /* The actual parser.  This can be called repeatedly. It updates
1801  * the index into the string and the state variable (which must
1802  * be initialized to 0).  It returns a result code, as above.  There
1803  * is no point calling the parser any more if it fails to advance to
1804  * the end of the string - it is stuck on an invalid character (or
1805  * terminated by '\0').
1806  *
1807  * Note that the pointer will consume an E or even an E+ and then leave
1808  * a 'maybe' state even though a preceding integer.fraction is valid.
1809  * The PNG_FP_WAS_VALID flag indicates that a preceding substring was
1810  * a valid number.  It's possible to recover from this by calling
1811  * the parser again (from the start, with state 0) but with a string
1812  * that omits the last character (i.e. set the size to the index of
1813  * the problem character.)  This has not been tested within libpng.
1814  */
1815 PNG_INTERNAL_FUNCTION(int,png_check_fp_number,(png_const_charp string,
1816    png_size_t size, int *statep, png_size_tp whereami),PNG_EMPTY);
1817 
1818 /* This is the same but it checks a complete string and returns true
1819  * only if it just contains a floating point number.  As of 1.5.4 this
1820  * function also returns the state at the end of parsing the number if
1821  * it was valid (otherwise it returns 0.)  This can be used for testing
1822  * for negative or zero values using the sticky flag.
1823  */
1824 PNG_INTERNAL_FUNCTION(int,png_check_fp_string,(png_const_charp string,
1825    png_size_t size),PNG_EMPTY);
1826 #endif /* pCAL || sCAL */
1827 
1828 #if defined(PNG_GAMMA_SUPPORTED) ||\
1829     defined(PNG_INCH_CONVERSIONS_SUPPORTED) || defined(PNG_READ_pHYs_SUPPORTED)
1830 /* Added at libpng version 1.5.0 */
1831 /* This is a utility to provide a*times/div (rounded) and indicate
1832  * if there is an overflow.  The result is a boolean - false (0)
1833  * for overflow, true (1) if no overflow, in which case *res
1834  * holds the result.
1835  */
1836 PNG_INTERNAL_FUNCTION(int,png_muldiv,(png_fixed_point_p res, png_fixed_point a,
1837    png_int_32 multiplied_by, png_int_32 divided_by),PNG_EMPTY);
1838 #endif
1839 
1840 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_INCH_CONVERSIONS_SUPPORTED)
1841 /* Same deal, but issue a warning on overflow and return 0. */
1842 PNG_INTERNAL_FUNCTION(png_fixed_point,png_muldiv_warn,
1843    (png_const_structrp png_ptr, png_fixed_point a, png_int_32 multiplied_by,
1844    png_int_32 divided_by),PNG_EMPTY);
1845 #endif
1846 
1847 #ifdef PNG_GAMMA_SUPPORTED
1848 /* Calculate a reciprocal - used for gamma values.  This returns
1849  * 0 if the argument is 0 in order to maintain an undefined value;
1850  * there are no warnings.
1851  */
1852 PNG_INTERNAL_FUNCTION(png_fixed_point,png_reciprocal,(png_fixed_point a),
1853    PNG_EMPTY);
1854 
1855 #ifdef PNG_READ_GAMMA_SUPPORTED
1856 /* The same but gives a reciprocal of the product of two fixed point
1857  * values.  Accuracy is suitable for gamma calculations but this is
1858  * not exact - use png_muldiv for that.  Only required at present on read.
1859  */
1860 PNG_INTERNAL_FUNCTION(png_fixed_point,png_reciprocal2,(png_fixed_point a,
1861    png_fixed_point b),PNG_EMPTY);
1862 #endif
1863 
1864 /* Return true if the gamma value is significantly different from 1.0 */
1865 PNG_INTERNAL_FUNCTION(int,png_gamma_significant,(png_fixed_point gamma_value),
1866    PNG_EMPTY);
1867 #endif
1868 
1869 #ifdef PNG_READ_GAMMA_SUPPORTED
1870 /* Internal fixed point gamma correction.  These APIs are called as
1871  * required to convert single values - they don't need to be fast,
1872  * they are not used when processing image pixel values.
1873  *
1874  * While the input is an 'unsigned' value it must actually be the
1875  * correct bit value - 0..255 or 0..65535 as required.
1876  */
1877 PNG_INTERNAL_FUNCTION(png_uint_16,png_gamma_correct,(png_structrp png_ptr,
1878    unsigned int value, png_fixed_point gamma_value),PNG_EMPTY);
1879 PNG_INTERNAL_FUNCTION(png_uint_16,png_gamma_16bit_correct,(unsigned int value,
1880    png_fixed_point gamma_value),PNG_EMPTY);
1881 PNG_INTERNAL_FUNCTION(png_byte,png_gamma_8bit_correct,(unsigned int value,
1882    png_fixed_point gamma_value),PNG_EMPTY);
1883 PNG_INTERNAL_FUNCTION(void,png_destroy_gamma_table,(png_structrp png_ptr),
1884    PNG_EMPTY);
1885 PNG_INTERNAL_FUNCTION(void,png_build_gamma_table,(png_structrp png_ptr,
1886    int bit_depth),PNG_EMPTY);
1887 #endif
1888 
1889 /* SIMPLIFIED READ/WRITE SUPPORT */
1890 #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
1891    defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
1892 /* The internal structure that png_image::opaque points to. */
1893 typedef struct png_control
1894 {
1895    png_structp png_ptr;
1896    png_infop   info_ptr;
1897    png_voidp   error_buf;           /* Always a jmp_buf at present. */
1898 
1899    png_const_bytep memory;          /* Memory buffer. */
1900    png_size_t      size;            /* Size of the memory buffer. */
1901 
1902    unsigned int for_write       :1; /* Otherwise it is a read structure */
1903    unsigned int owned_file      :1; /* We own the file in io_ptr */
1904 } png_control;
1905 
1906 /* Return the pointer to the jmp_buf from a png_control: necessary because C
1907  * does not reveal the type of the elements of jmp_buf.
1908  */
1909 #ifdef __cplusplus
1910 #  define png_control_jmp_buf(pc) (((jmp_buf*)((pc)->error_buf))[0])
1911 #else
1912 #  define png_control_jmp_buf(pc) ((pc)->error_buf)
1913 #endif
1914 
1915 /* Utility to safely execute a piece of libpng code catching and logging any
1916  * errors that might occur.  Returns true on success, false on failure (either
1917  * of the function or as a result of a png_error.)
1918  */
1919 PNG_INTERNAL_CALLBACK(void,png_safe_error,(png_structp png_ptr,
1920    png_const_charp error_message),PNG_NORETURN);
1921 
1922 #ifdef PNG_WARNINGS_SUPPORTED
1923 PNG_INTERNAL_CALLBACK(void,png_safe_warning,(png_structp png_ptr,
1924    png_const_charp warning_message),PNG_EMPTY);
1925 #else
1926 #  define png_safe_warning 0/*dummy argument*/
1927 #endif
1928 
1929 PNG_INTERNAL_FUNCTION(int,png_safe_execute,(png_imagep image,
1930    int (*function)(png_voidp), png_voidp arg),PNG_EMPTY);
1931 
1932 /* Utility to log an error; this also cleans up the png_image; the function
1933  * always returns 0 (false).
1934  */
1935 PNG_INTERNAL_FUNCTION(int,png_image_error,(png_imagep image,
1936    png_const_charp error_message),PNG_EMPTY);
1937 
1938 #ifndef PNG_SIMPLIFIED_READ_SUPPORTED
1939 /* png_image_free is used by the write code but not exported */
1940 PNG_INTERNAL_FUNCTION(void, png_image_free, (png_imagep image), PNG_EMPTY);
1941 #endif /* !SIMPLIFIED_READ */
1942 
1943 #endif /* SIMPLIFIED READ/WRITE */
1944 
1945 /* These are initialization functions for hardware specific PNG filter
1946  * optimizations; list these here then select the appropriate one at compile
1947  * time using the macro PNG_FILTER_OPTIMIZATIONS.  If the macro is not defined
1948  * the generic code is used.
1949  */
1950 #ifdef PNG_FILTER_OPTIMIZATIONS
1951 PNG_INTERNAL_FUNCTION(void, PNG_FILTER_OPTIMIZATIONS, (png_structp png_ptr,
1952    unsigned int bpp), PNG_EMPTY);
1953    /* Just declare the optimization that will be used */
1954 #else
1955    /* List *all* the possible optimizations here - this branch is required if
1956     * the builder of libpng passes the definition of PNG_FILTER_OPTIMIZATIONS in
1957     * CFLAGS in place of CPPFLAGS *and* uses symbol prefixing.
1958     */
1959 PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_neon,
1960    (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
1961 #endif
1962 
1963 /* Maintainer: Put new private prototypes here ^ */
1964 
1965 #include "pngdebug.h"
1966 
1967 #ifdef __cplusplus
1968 }
1969 #endif
1970 
1971 #endif /* PNG_VERSION_INFO_ONLY */
1972 #endif /* PNGPRIV_H */