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  * Last changed in libpng 1.6.26 [October 20, 2016]
  33  * Copyright (c) 1998-2002,2004,2006-2016 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  * This code is released under the libpng license.
  38  * For conditions of distribution and use, see the disclaimer
  39  * and license in png.h
  40  */
  41 
  42 /* The symbols declared in this file (including the functions declared
  43  * as extern) are PRIVATE.  They are not part of the libpng public
  44  * interface, and are not recommended for use by regular applications.
  45  * Some of them may become public in the future; others may stay private,
  46  * change in an incompatible way, or even disappear.
  47  * Although the libpng users are not forbidden to include this header,
  48  * they should be well aware of the issues that may arise from doing so.
  49  */
  50 
  51 #ifndef PNGPRIV_H
  52 #define PNGPRIV_H
  53 
  54 /* Feature Test Macros.  The following are defined here to ensure that correctly
  55  * implemented libraries reveal the APIs libpng needs to build and hide those
  56  * that are not needed and potentially damaging to the compilation.
  57  *
  58  * Feature Test Macros must be defined before any system header is included (see
  59  * POSIX 1003.1 2.8.2 "POSIX Symbols."
  60  *
  61  * These macros only have an effect if the operating system supports either
  62  * POSIX 1003.1 or C99, or both.  On other operating systems (particularly
  63  * Windows/Visual Studio) there is no effect; the OS specific tests below are
  64  * still required (as of 2011-05-02.)
  65  */
  66 #define _POSIX_SOURCE 1 /* Just the POSIX 1003.1 and C89 APIs */
  67 
  68 #ifndef PNG_VERSION_INFO_ONLY
  69 /* Standard library headers not required by png.h: */
  70 #  include <stdlib.h>
  71 #  include <string.h>
  72 #endif
  73 
  74 #define PNGLIB_BUILD /*libpng is being built, not used*/
  75 
  76 /* If HAVE_CONFIG_H is defined during the build then the build system must
  77  * provide an appropriate "config.h" file on the include path.  The header file
  78  * must provide definitions as required below (search for "HAVE_CONFIG_H");
  79  * see configure.ac for more details of the requirements.  The macro
  80  * "PNG_NO_CONFIG_H" is provided for maintainers to test for dependencies on
  81  * 'configure'; define this macro to prevent the configure build including the
  82  * configure generated config.h.  Libpng is expected to compile without *any*
  83  * special build system support on a reasonably ANSI-C compliant system.
  84  */
  85 #if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
  86 #  include <config.h>
  87 
  88    /* Pick up the definition of 'restrict' from config.h if it was read: */
  89 #  define PNG_RESTRICT restrict
  90 #endif
  91 
  92 /* To support symbol prefixing it is necessary to know *before* including png.h
  93  * whether the fixed point (and maybe other) APIs are exported, because if they
  94  * are not internal definitions may be required.  This is handled below just
  95  * before png.h is included, but load the configuration now if it is available.
  96  */
  97 #ifndef PNGLCONF_H
  98 #  include "pnglibconf.h"
  99 #endif
 100 
 101 /* Local renames may change non-exported API functions from png.h */
 102 #if defined(PNG_PREFIX) && !defined(PNGPREFIX_H)
 103 #  include "pngprefix.h"
 104 #endif
 105 
 106 #ifdef PNG_USER_CONFIG
 107 #  include "pngusr.h"
 108    /* These should have been defined in pngusr.h */
 109 #  ifndef PNG_USER_PRIVATEBUILD
 110 #    define PNG_USER_PRIVATEBUILD "Custom libpng build"
 111 #  endif
 112 #  ifndef PNG_USER_DLLFNAME_POSTFIX
 113 #    define PNG_USER_DLLFNAME_POSTFIX "Cb"
 114 #  endif
 115 #endif
 116 
 117 /* Compile time options.
 118  * =====================
 119  * In a multi-arch build the compiler may compile the code several times for the
 120  * same object module, producing different binaries for different architectures.
 121  * When this happens configure-time setting of the target host options cannot be
 122  * done and this interferes with the handling of the ARM NEON optimizations, and
 123  * possibly other similar optimizations.  Put additional tests here; in general
 124  * this is needed when the same option can be changed at both compile time and
 125  * run time depending on the target OS (i.e. iOS vs Android.)
 126  *
 127  * NOTE: symbol prefixing does not pass $(CFLAGS) to the preprocessor, because
 128  * this is not possible with certain compilers (Oracle SUN OS CC), as a result
 129  * it is necessary to ensure that all extern functions that *might* be used
 130  * regardless of $(CFLAGS) get declared in this file.  The test on __ARM_NEON__
 131  * below is one example of this behavior because it is controlled by the
 132  * presence or not of -mfpu=neon on the GCC command line, it is possible to do
 133  * this in $(CC), e.g. "CC=gcc -mfpu=neon", but people who build libpng rarely
 134  * do this.
 135  */
 136 #ifndef PNG_ARM_NEON_OPT
 137    /* ARM NEON optimizations are being controlled by the compiler settings,
 138     * typically the target FPU.  If the FPU has been set to NEON (-mfpu=neon
 139     * with GCC) then the compiler will define __ARM_NEON__ and we can rely
 140     * unconditionally on NEON instructions not crashing, otherwise we must
 141     * disable use of NEON instructions.
 142     *
 143     * NOTE: at present these optimizations depend on 'ALIGNED_MEMORY', so they
 144     * can only be turned on automatically if that is supported too.  If
 145     * PNG_ARM_NEON_OPT is set in CPPFLAGS (to >0) then arm/arm_init.c will fail
 146     * to compile with an appropriate #error if ALIGNED_MEMORY has been turned
 147     * off.
 148     *
 149     * Note that gcc-4.9 defines __ARM_NEON instead of the deprecated
 150     * __ARM_NEON__, so we check both variants.
 151     *
 152     * To disable ARM_NEON optimizations entirely, and skip compiling the
 153     * associated assembler code, pass --enable-arm-neon=no to configure
 154     * or put -DPNG_ARM_NEON_OPT=0 in CPPFLAGS.
 155     */
 156 #  if (defined(__ARM_NEON__) || defined(__ARM_NEON)) && \
 157    defined(PNG_ALIGNED_MEMORY_SUPPORTED)
 158 #     define PNG_ARM_NEON_OPT 2
 159 #  else
 160 #     define PNG_ARM_NEON_OPT 0
 161 #  endif
 162 #endif
 163 
 164 #if PNG_ARM_NEON_OPT > 0
 165    /* NEON optimizations are to be at least considered by libpng, so enable the
 166     * callbacks to do this.
 167     */
 168 #  define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_neon
 169 
 170    /* By default the 'intrinsics' code in arm/filter_neon_intrinsics.c is used
 171     * if possible - if __ARM_NEON__ is set and the compiler version is not known
 172     * to be broken.  This is controlled by PNG_ARM_NEON_IMPLEMENTATION which can
 173     * be:
 174     *
 175     *    1  The intrinsics code (the default with __ARM_NEON__)
 176     *    2  The hand coded assembler (the default without __ARM_NEON__)
 177     *
 178     * It is possible to set PNG_ARM_NEON_IMPLEMENTATION in CPPFLAGS, however
 179     * this is *NOT* supported and may cease to work even after a minor revision
 180     * to libpng.  It *is* valid to do this for testing purposes, e.g. speed
 181     * testing or a new compiler, but the results should be communicated to the
 182     * libpng implementation list for incorporation in the next minor release.
 183     */
 184 #  ifndef PNG_ARM_NEON_IMPLEMENTATION
 185 #     if defined(__ARM_NEON__) || defined(__ARM_NEON)
 186 #        if defined(__clang__)
 187             /* At present it is unknown by the libpng developers which versions
 188              * of clang support the intrinsics, however some or perhaps all
 189              * versions do not work with the assembler so this may be
 190              * irrelevant, so just use the default (do nothing here.)
 191              */
 192 #        elif defined(__GNUC__)
 193             /* GCC 4.5.4 NEON support is known to be broken.  4.6.3 is known to
 194              * work, so if this *is* GCC, or G++, look for a version >4.5
 195              */
 196 #           if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 6)
 197 #              define PNG_ARM_NEON_IMPLEMENTATION 2
 198 #           endif /* no GNUC support */
 199 #        endif /* __GNUC__ */
 200 #     else /* !defined __ARM_NEON__ */
 201          /* The 'intrinsics' code simply won't compile without this -mfpu=neon:
 202           */
 203 #        define PNG_ARM_NEON_IMPLEMENTATION 2
 204 #     endif /* __ARM_NEON__ */
 205 #  endif /* !PNG_ARM_NEON_IMPLEMENTATION */
 206 
 207 #  ifndef PNG_ARM_NEON_IMPLEMENTATION
 208       /* Use the intrinsics code by default. */
 209 #     define PNG_ARM_NEON_IMPLEMENTATION 1
 210 #  endif
 211 #endif /* PNG_ARM_NEON_OPT > 0 */
 212 
 213 #ifndef PNG_MIPS_MSA_OPT
 214 #  if defined(__mips_msa) && (__mips_isa_rev >= 5) && defined(PNG_ALIGNED_MEMORY_SUPPORTED)
 215 #     define PNG_MIPS_MSA_OPT 2
 216 #  else
 217 #     define PNG_MIPS_MSA_OPT 0
 218 #  endif
 219 #endif
 220 
 221 #if PNG_MIPS_MSA_OPT > 0
 222 #  define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_msa
 223 #  ifndef PNG_MIPS_MSA_IMPLEMENTATION
 224 #     if defined(__mips_msa)
 225 #        if defined(__clang__)
 226 #        elif defined(__GNUC__)
 227 #           if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 7)
 228 #              define PNG_MIPS_MSA_IMPLEMENTATION 2
 229 #           endif /* no GNUC support */
 230 #        endif /* __GNUC__ */
 231 #     else /* !defined __mips_msa */
 232 #        define PNG_MIPS_MSA_IMPLEMENTATION 2
 233 #     endif /* __mips_msa */
 234 #  endif /* !PNG_MIPS_MSA_IMPLEMENTATION */
 235 
 236 #  ifndef PNG_MIPS_MSA_IMPLEMENTATION
 237 #     define PNG_MIPS_MSA_IMPLEMENTATION 1
 238 #  endif
 239 #endif /* PNG_MIPS_MSA_OPT > 0 */
 240 
 241 
 242 /* Is this a build of a DLL where compilation of the object modules requires
 243  * different preprocessor settings to those required for a simple library?  If
 244  * so PNG_BUILD_DLL must be set.
 245  *
 246  * If libpng is used inside a DLL but that DLL does not export the libpng APIs
 247  * PNG_BUILD_DLL must not be set.  To avoid the code below kicking in build a
 248  * static library of libpng then link the DLL against that.
 249  */
 250 #ifndef PNG_BUILD_DLL
 251 #  ifdef DLL_EXPORT
 252       /* This is set by libtool when files are compiled for a DLL; libtool
 253        * always compiles twice, even on systems where it isn't necessary.  Set
 254        * PNG_BUILD_DLL in case it is necessary:
 255        */
 256 #     define PNG_BUILD_DLL
 257 #  else
 258 #     ifdef _WINDLL
 259          /* This is set by the Microsoft Visual Studio IDE in projects that
 260           * build a DLL.  It can't easily be removed from those projects (it
 261           * isn't visible in the Visual Studio UI) so it is a fairly reliable
 262           * indication that PNG_IMPEXP needs to be set to the DLL export
 263           * attributes.
 264           */
 265 #        define PNG_BUILD_DLL
 266 #     else
 267 #        ifdef __DLL__
 268             /* This is set by the Borland C system when compiling for a DLL
 269              * (as above.)
 270              */
 271 #           define PNG_BUILD_DLL
 272 #        else
 273             /* Add additional compiler cases here. */
 274 #        endif
 275 #     endif
 276 #  endif
 277 #endif /* Setting PNG_BUILD_DLL if required */
 278 
 279 /* See pngconf.h for more details: the builder of the library may set this on
 280  * the command line to the right thing for the specific compilation system or it
 281  * may be automagically set above (at present we know of no system where it does
 282  * need to be set on the command line.)
 283  *
 284  * PNG_IMPEXP must be set here when building the library to prevent pngconf.h
 285  * setting it to the "import" setting for a DLL build.
 286  */
 287 #ifndef PNG_IMPEXP
 288 #  ifdef PNG_BUILD_DLL
 289 #     define PNG_IMPEXP PNG_DLL_EXPORT
 290 #  else
 291       /* Not building a DLL, or the DLL doesn't require specific export
 292        * definitions.
 293        */
 294 #     define PNG_IMPEXP
 295 #  endif
 296 #endif
 297 
 298 /* No warnings for private or deprecated functions in the build: */
 299 #ifndef PNG_DEPRECATED
 300 #  define PNG_DEPRECATED
 301 #endif
 302 #ifndef PNG_PRIVATE
 303 #  define PNG_PRIVATE
 304 #endif
 305 
 306 /* Symbol preprocessing support.
 307  *
 308  * To enable listing global, but internal, symbols the following macros should
 309  * always be used to declare an extern data or function object in this file.
 310  */
 311 #ifndef PNG_INTERNAL_DATA
 312 #  define PNG_INTERNAL_DATA(type, name, array) PNG_LINKAGE_DATA type name array
 313 #endif
 314 
 315 #ifndef PNG_INTERNAL_FUNCTION
 316 #  define PNG_INTERNAL_FUNCTION(type, name, args, attributes)\
 317       PNG_LINKAGE_FUNCTION PNG_FUNCTION(type, name, args, PNG_EMPTY attributes)
 318 #endif
 319 
 320 #ifndef PNG_INTERNAL_CALLBACK
 321 #  define PNG_INTERNAL_CALLBACK(type, name, args, attributes)\
 322       PNG_LINKAGE_CALLBACK PNG_FUNCTION(type, (PNGCBAPI name), args,\
 323          PNG_EMPTY attributes)
 324 #endif
 325 
 326 /* If floating or fixed point APIs are disabled they may still be compiled
 327  * internally.  To handle this make sure they are declared as the appropriate
 328  * internal extern function (otherwise the symbol prefixing stuff won't work and
 329  * the functions will be used without definitions.)
 330  *
 331  * NOTE: although all the API functions are declared here they are not all
 332  * actually built!  Because the declarations are still made it is necessary to
 333  * fake out types that they depend on.
 334  */
 335 #ifndef PNG_FP_EXPORT
 336 #  ifndef PNG_FLOATING_POINT_SUPPORTED
 337 #     define PNG_FP_EXPORT(ordinal, type, name, args)\
 338          PNG_INTERNAL_FUNCTION(type, name, args, PNG_EMPTY);
 339 #     ifndef PNG_VERSION_INFO_ONLY
 340          typedef struct png_incomplete png_double;
 341          typedef png_double*           png_doublep;
 342          typedef const png_double*     png_const_doublep;
 343          typedef png_double**          png_doublepp;
 344 #     endif
 345 #  endif
 346 #endif
 347 #ifndef PNG_FIXED_EXPORT
 348 #  ifndef PNG_FIXED_POINT_SUPPORTED
 349 #     define PNG_FIXED_EXPORT(ordinal, type, name, args)\
 350          PNG_INTERNAL_FUNCTION(type, name, args, PNG_EMPTY);
 351 #  endif
 352 #endif
 353 
 354 #include "png.h"
 355 
 356 /* pngconf.h does not set PNG_DLL_EXPORT unless it is required, so: */
 357 #ifndef PNG_DLL_EXPORT
 358 #  define PNG_DLL_EXPORT
 359 #endif
 360 
 361 /* This is a global switch to set the compilation for an installed system
 362  * (a release build).  It can be set for testing debug builds to ensure that
 363  * they will compile when the build type is switched to RC or STABLE, the
 364  * default is just to use PNG_LIBPNG_BUILD_BASE_TYPE.  Set this in CPPFLAGS
 365  * with either:
 366  *
 367  *   -DPNG_RELEASE_BUILD Turns on the release compile path
 368  *   -DPNG_RELEASE_BUILD=0 Turns it off
 369  * or in your pngusr.h with
 370  *   #define PNG_RELEASE_BUILD=1 Turns on the release compile path
 371  *   #define PNG_RELEASE_BUILD=0 Turns it off
 372  */
 373 #ifndef PNG_RELEASE_BUILD
 374 #  define PNG_RELEASE_BUILD (PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC)
 375 #endif
 376 
 377 /* SECURITY and SAFETY:
 378  *
 379  * libpng is built with support for internal limits on image dimensions and
 380  * memory usage.  These are documented in scripts/pnglibconf.dfa of the
 381  * source and recorded in the machine generated header file pnglibconf.h.
 382  */
 383 
 384 /* If you are running on a machine where you cannot allocate more
 385  * than 64K of memory at once, uncomment this.  While libpng will not
 386  * normally need that much memory in a chunk (unless you load up a very
 387  * large file), zlib needs to know how big of a chunk it can use, and
 388  * libpng thus makes sure to check any memory allocation to verify it
 389  * will fit into memory.
 390  *
 391  * zlib provides 'MAXSEG_64K' which, if defined, indicates the
 392  * same limit and pngconf.h (already included) sets the limit
 393  * if certain operating systems are detected.
 394  */
 395 #if defined(MAXSEG_64K) && !defined(PNG_MAX_MALLOC_64K)
 396 #  define PNG_MAX_MALLOC_64K
 397 #endif
 398 
 399 #ifndef PNG_UNUSED
 400 /* Unused formal parameter warnings are silenced using the following macro
 401  * which is expected to have no bad effects on performance (optimizing
 402  * compilers will probably remove it entirely).  Note that if you replace
 403  * it with something other than whitespace, you must include the terminating
 404  * semicolon.
 405  */
 406 #  define PNG_UNUSED(param) (void)param;
 407 #endif
 408 
 409 /* Just a little check that someone hasn't tried to define something
 410  * contradictory.
 411  */
 412 #if (PNG_ZBUF_SIZE > 65536L) && defined(PNG_MAX_MALLOC_64K)
 413 #  undef PNG_ZBUF_SIZE
 414 #  define PNG_ZBUF_SIZE 65536L
 415 #endif
 416 
 417 /* If warnings or errors are turned off the code is disabled or redirected here.
 418  * From 1.5.4 functions have been added to allow very limited formatting of
 419  * error and warning messages - this code will also be disabled here.
 420  */
 421 #ifdef PNG_WARNINGS_SUPPORTED
 422 #  define PNG_WARNING_PARAMETERS(p) png_warning_parameters p;
 423 #else
 424 #  define png_warning_parameter(p,number,string) ((void)0)
 425 #  define png_warning_parameter_unsigned(p,number,format,value) ((void)0)
 426 #  define png_warning_parameter_signed(p,number,format,value) ((void)0)
 427 #  define png_formatted_warning(pp,p,message) ((void)(pp))
 428 #  define PNG_WARNING_PARAMETERS(p)
 429 #endif
 430 #ifndef PNG_ERROR_TEXT_SUPPORTED
 431 #  define png_fixed_error(s1,s2) png_err(s1)
 432 #endif
 433 
 434 /* C allows up-casts from (void*) to any pointer and (const void*) to any
 435  * pointer to a const object.  C++ regards this as a type error and requires an
 436  * explicit, static, cast and provides the static_cast<> rune to ensure that
 437  * const is not cast away.
 438  */
 439 #ifdef __cplusplus
 440 #  define png_voidcast(type, value) static_cast<type>(value)
 441 #  define png_constcast(type, value) const_cast<type>(value)
 442 #  define png_aligncast(type, value) \
 443    static_cast<type>(static_cast<void*>(value))
 444 #  define png_aligncastconst(type, value) \
 445    static_cast<type>(static_cast<const void*>(value))
 446 #else
 447 #  define png_voidcast(type, value) (value)
 448 #  define png_constcast(type, value) ((type)(value))
 449 #  define png_aligncast(type, value) ((void*)(value))
 450 #  define png_aligncastconst(type, value) ((const void*)(value))
 451 #endif /* __cplusplus */
 452 
 453 /* Some fixed point APIs are still required even if not exported because
 454  * they get used by the corresponding floating point APIs.  This magic
 455  * deals with this:
 456  */
 457 #ifdef PNG_FIXED_POINT_SUPPORTED
 458 #  define PNGFAPI PNGAPI
 459 #else
 460 #  define PNGFAPI /* PRIVATE */
 461 #endif
 462 
 463 #ifndef PNG_VERSION_INFO_ONLY
 464 /* Other defines specific to compilers can go here.  Try to keep
 465  * them inside an appropriate ifdef/endif pair for portability.
 466  */
 467 #if defined(PNG_FLOATING_POINT_SUPPORTED) ||\
 468     defined(PNG_FLOATING_ARITHMETIC_SUPPORTED)
 469    /* png.c requires the following ANSI-C constants if the conversion of
 470     * floating point to ASCII is implemented therein:
 471     *
 472     *  DBL_DIG  Maximum number of decimal digits (can be set to any constant)
 473     *  DBL_MIN  Smallest normalized fp number (can be set to an arbitrary value)
 474     *  DBL_MAX  Maximum floating point number (can be set to an arbitrary value)
 475     */
 476 #  include <float.h>
 477 
 478 #  if (defined(__MWERKS__) && defined(macintosh)) || defined(applec) || \
 479     defined(THINK_C) || defined(__SC__) || defined(TARGET_OS_MAC)
 480    /* We need to check that <math.h> hasn't already been included earlier
 481     * as it seems it doesn't agree with <fp.h>, yet we should really use
 482     * <fp.h> if possible.
 483     */
 484 #    if !defined(__MATH_H__) && !defined(__MATH_H) && !defined(__cmath__)
 485 #      include <fp.h>
 486 #    endif
 487 #  else
 488 #    include <math.h>
 489 #  endif
 490 #  if defined(_AMIGA) && defined(__SASC) && defined(_M68881)
 491    /* Amiga SAS/C: We must include builtin FPU functions when compiling using
 492     * MATH=68881
 493     */
 494 #    include <m68881.h>
 495 #  endif
 496 #endif
 497 
 498 /* This provides the non-ANSI (far) memory allocation routines. */
 499 #if defined(__TURBOC__) && defined(__MSDOS__)
 500 #  include <mem.h>
 501 #  include <alloc.h>
 502 #endif
 503 
 504 #if defined(WIN32) || defined(_Windows) || defined(_WINDOWS) || \
 505     defined(_WIN32) || defined(__WIN32__)
 506 #  include <windows.h>  /* defines _WINDOWS_ macro */
 507 #endif
 508 #endif /* PNG_VERSION_INFO_ONLY */
 509 
 510 /* Moved here around 1.5.0beta36 from pngconf.h */
 511 /* Users may want to use these so they are not private.  Any library
 512  * functions that are passed far data must be model-independent.
 513  */
 514 
 515 /* Memory model/platform independent fns */
 516 #ifndef PNG_ABORT
 517 #  ifdef _WINDOWS_
 518 #    define PNG_ABORT() ExitProcess(0)
 519 #  else
 520 #    define PNG_ABORT() abort()
 521 #  endif
 522 #endif
 523 
 524 /* These macros may need to be architecture dependent. */
 525 #define PNG_ALIGN_NONE   0 /* do not use data alignment */
 526 #define PNG_ALIGN_ALWAYS 1 /* assume unaligned accesses are OK */
 527 #ifdef offsetof
 528 #  define PNG_ALIGN_OFFSET 2 /* use offsetof to determine alignment */
 529 #else
 530 #  define PNG_ALIGN_OFFSET -1 /* prevent the use of this */
 531 #endif
 532 #define PNG_ALIGN_SIZE   3 /* use sizeof to determine alignment */
 533 
 534 #ifndef PNG_ALIGN_TYPE
 535    /* Default to using aligned access optimizations and requiring alignment to a
 536     * multiple of the data type size.  Override in a compiler specific fashion
 537     * if necessary by inserting tests here:
 538     */
 539 #  define PNG_ALIGN_TYPE PNG_ALIGN_SIZE
 540 #endif
 541 
 542 #if PNG_ALIGN_TYPE == PNG_ALIGN_SIZE
 543    /* This is used because in some compiler implementations non-aligned
 544     * structure members are supported, so the offsetof approach below fails.
 545     * Set PNG_ALIGN_SIZE=0 for compiler combinations where unaligned access
 546     * is good for performance.  Do not do this unless you have tested the result
 547     * and understand it.
 548     */
 549 #  define png_alignof(type) (sizeof (type))
 550 #else
 551 #  if PNG_ALIGN_TYPE == PNG_ALIGN_OFFSET
 552 #     define png_alignof(type) offsetof(struct{char c; type t;}, t)
 553 #  else
 554 #     if PNG_ALIGN_TYPE == PNG_ALIGN_ALWAYS
 555 #        define png_alignof(type) (1)
 556 #     endif
 557       /* Else leave png_alignof undefined to prevent use thereof */
 558 #  endif
 559 #endif
 560 
 561 /* This implicitly assumes alignment is always to a power of 2. */
 562 #ifdef png_alignof
 563 #  define png_isaligned(ptr, type)\
 564    (((type)((const char*)ptr-(const char*)0) & \
 565    (type)(png_alignof(type)-1)) == 0)
 566 #else
 567 #  define png_isaligned(ptr, type) 0
 568 #endif
 569 
 570 /* End of memory model/platform independent support */
 571 /* End of 1.5.0beta36 move from pngconf.h */
 572 
 573 /* CONSTANTS and UTILITY MACROS
 574  * These are used internally by libpng and not exposed in the API
 575  */
 576 
 577 /* Various modes of operation.  Note that after an init, mode is set to
 578  * zero automatically when the structure is created.  Three of these
 579  * are defined in png.h because they need to be visible to applications
 580  * that call png_set_unknown_chunk().
 581  */
 582 /* #define PNG_HAVE_IHDR            0x01U (defined in png.h) */
 583 /* #define PNG_HAVE_PLTE            0x02U (defined in png.h) */
 584 #define PNG_HAVE_IDAT               0x04U
 585 /* #define PNG_AFTER_IDAT           0x08U (defined in png.h) */
 586 #define PNG_HAVE_IEND               0x10U
 587                    /*               0x20U (unused) */
 588                    /*               0x40U (unused) */
 589                    /*               0x80U (unused) */
 590 #define PNG_HAVE_CHUNK_HEADER      0x100U
 591 #define PNG_WROTE_tIME             0x200U
 592 #define PNG_WROTE_INFO_BEFORE_PLTE 0x400U
 593 #define PNG_BACKGROUND_IS_GRAY     0x800U
 594 #define PNG_HAVE_PNG_SIGNATURE    0x1000U
 595 #define PNG_HAVE_CHUNK_AFTER_IDAT 0x2000U /* Have another chunk after IDAT */
 596                    /*             0x4000U (unused) */
 597 #define PNG_IS_READ_STRUCT        0x8000U /* Else is a write struct */
 598 
 599 /* Flags for the transformations the PNG library does on the image data */
 600 #define PNG_BGR                 0x0001U
 601 #define PNG_INTERLACE           0x0002U
 602 #define PNG_PACK                0x0004U
 603 #define PNG_SHIFT               0x0008U
 604 #define PNG_SWAP_BYTES          0x0010U
 605 #define PNG_INVERT_MONO         0x0020U
 606 #define PNG_QUANTIZE            0x0040U
 607 #define PNG_COMPOSE             0x0080U    /* Was PNG_BACKGROUND */
 608 #define PNG_BACKGROUND_EXPAND   0x0100U
 609 #define PNG_EXPAND_16           0x0200U    /* Added to libpng 1.5.2 */
 610 #define PNG_16_TO_8             0x0400U    /* Becomes 'chop' in 1.5.4 */
 611 #define PNG_RGBA                0x0800U
 612 #define PNG_EXPAND              0x1000U
 613 #define PNG_GAMMA               0x2000U
 614 #define PNG_GRAY_TO_RGB         0x4000U
 615 #define PNG_FILLER              0x8000U
 616 #define PNG_PACKSWAP           0x10000U
 617 #define PNG_SWAP_ALPHA         0x20000U
 618 #define PNG_STRIP_ALPHA        0x40000U
 619 #define PNG_INVERT_ALPHA       0x80000U
 620 #define PNG_USER_TRANSFORM    0x100000U
 621 #define PNG_RGB_TO_GRAY_ERR   0x200000U
 622 #define PNG_RGB_TO_GRAY_WARN  0x400000U
 623 #define PNG_RGB_TO_GRAY       0x600000U /* two bits, RGB_TO_GRAY_ERR|WARN */
 624 #define PNG_ENCODE_ALPHA      0x800000U /* Added to libpng-1.5.4 */
 625 #define PNG_ADD_ALPHA        0x1000000U /* Added to libpng-1.2.7 */
 626 #define PNG_EXPAND_tRNS      0x2000000U /* Added to libpng-1.2.9 */
 627 #define PNG_SCALE_16_TO_8    0x4000000U /* Added to libpng-1.5.4 */
 628                        /*    0x8000000U unused */
 629                        /*   0x10000000U unused */
 630                        /*   0x20000000U unused */
 631                        /*   0x40000000U unused */
 632 /* Flags for png_create_struct */
 633 #define PNG_STRUCT_PNG   0x0001U
 634 #define PNG_STRUCT_INFO  0x0002U
 635 
 636 /* Flags for the png_ptr->flags rather than declaring a byte for each one */
 637 #define PNG_FLAG_ZLIB_CUSTOM_STRATEGY     0x0001U
 638 #define PNG_FLAG_ZSTREAM_INITIALIZED      0x0002U /* Added to libpng-1.6.0 */
 639                                   /*      0x0004U    unused */
 640 #define PNG_FLAG_ZSTREAM_ENDED            0x0008U /* Added to libpng-1.6.0 */
 641                                   /*      0x0010U    unused */
 642                                   /*      0x0020U    unused */
 643 #define PNG_FLAG_ROW_INIT                 0x0040U
 644 #define PNG_FLAG_FILLER_AFTER             0x0080U
 645 #define PNG_FLAG_CRC_ANCILLARY_USE        0x0100U
 646 #define PNG_FLAG_CRC_ANCILLARY_NOWARN     0x0200U
 647 #define PNG_FLAG_CRC_CRITICAL_USE         0x0400U
 648 #define PNG_FLAG_CRC_CRITICAL_IGNORE      0x0800U
 649 #define PNG_FLAG_ASSUME_sRGB              0x1000U /* Added to libpng-1.5.4 */
 650 #define PNG_FLAG_OPTIMIZE_ALPHA           0x2000U /* Added to libpng-1.5.4 */
 651 #define PNG_FLAG_DETECT_UNINITIALIZED     0x4000U /* Added to libpng-1.5.4 */
 652 /* #define PNG_FLAG_KEEP_UNKNOWN_CHUNKS      0x8000U */
 653 /* #define PNG_FLAG_KEEP_UNSAFE_CHUNKS      0x10000U */
 654 #define PNG_FLAG_LIBRARY_MISMATCH        0x20000U
 655 #define PNG_FLAG_STRIP_ERROR_NUMBERS     0x40000U
 656 #define PNG_FLAG_STRIP_ERROR_TEXT        0x80000U
 657 #define PNG_FLAG_BENIGN_ERRORS_WARN     0x100000U /* Added to libpng-1.4.0 */
 658 #define PNG_FLAG_APP_WARNINGS_WARN      0x200000U /* Added to libpng-1.6.0 */
 659 #define PNG_FLAG_APP_ERRORS_WARN        0x400000U /* Added to libpng-1.6.0 */
 660                                   /*    0x800000U    unused */
 661                                   /*   0x1000000U    unused */
 662                                   /*   0x2000000U    unused */
 663                                   /*   0x4000000U    unused */
 664                                   /*   0x8000000U    unused */
 665                                   /*  0x10000000U    unused */
 666                                   /*  0x20000000U    unused */
 667                                   /*  0x40000000U    unused */
 668 
 669 #define PNG_FLAG_CRC_ANCILLARY_MASK (PNG_FLAG_CRC_ANCILLARY_USE | \
 670                                      PNG_FLAG_CRC_ANCILLARY_NOWARN)
 671 
 672 #define PNG_FLAG_CRC_CRITICAL_MASK  (PNG_FLAG_CRC_CRITICAL_USE | \
 673                                      PNG_FLAG_CRC_CRITICAL_IGNORE)
 674 
 675 #define PNG_FLAG_CRC_MASK           (PNG_FLAG_CRC_ANCILLARY_MASK | \
 676                                      PNG_FLAG_CRC_CRITICAL_MASK)
 677 
 678 /* Save typing and make code easier to understand */
 679 
 680 #define PNG_COLOR_DIST(c1, c2) (abs((int)((c1).red) - (int)((c2).red)) + \
 681    abs((int)((c1).green) - (int)((c2).green)) + \
 682    abs((int)((c1).blue) - (int)((c2).blue)))
 683 
 684 /* Added to libpng-1.6.0: scale a 16-bit value in the range 0..65535 to 0..255
 685  * by dividing by 257 *with rounding*.  This macro is exact for the given range.
 686  * See the discourse in pngrtran.c png_do_scale_16_to_8.  The values in the
 687  * macro were established by experiment (modifying the added value).  The macro
 688  * has a second variant that takes a value already scaled by 255 and divides by
 689  * 65535 - this has a maximum error of .502.  Over the range 0..65535*65535 it
 690  * only gives off-by-one errors and only for 0.5% (1 in 200) of the values.
 691  */
 692 #define PNG_DIV65535(v24) (((v24) + 32895) >> 16)
 693 #define PNG_DIV257(v16) PNG_DIV65535((png_uint_32)(v16) * 255)
 694 
 695 /* Added to libpng-1.2.6 JB */
 696 #define PNG_ROWBYTES(pixel_bits, width) \
 697     ((pixel_bits) >= 8 ? \
 698     ((png_size_t)(width) * (((png_size_t)(pixel_bits)) >> 3)) : \
 699     (( ((png_size_t)(width) * ((png_size_t)(pixel_bits))) + 7) >> 3) )
 700 
 701 /* This returns the number of trailing bits in the last byte of a row, 0 if the
 702  * last byte is completely full of pixels.  It is, in principle, (pixel_bits x
 703  * width) % 8, but that would overflow for large 'width'.  The second macro is
 704  * the same except that it returns the number of unused bits in the last byte;
 705  * (8-TRAILBITS), but 0 when TRAILBITS is 0.
 706  *
 707  * NOTE: these macros are intended to be self-evidently correct and never
 708  * overflow on the assumption that pixel_bits is in the range 0..255.  The
 709  * arguments are evaluated only once and they can be signed (e.g. as a result of
 710  * the integral promotions).  The result of the expression always has type
 711  * (png_uint_32), however the compiler always knows it is in the range 0..7.
 712  */
 713 #define PNG_TRAILBITS(pixel_bits, width) \
 714     (((pixel_bits) * ((width) % (png_uint_32)8)) % 8)
 715 
 716 #define PNG_PADBITS(pixel_bits, width) \
 717     ((8 - PNG_TRAILBITS(pixel_bits, width)) % 8)
 718 
 719 /* PNG_OUT_OF_RANGE returns true if value is outside the range
 720  * ideal-delta..ideal+delta.  Each argument is evaluated twice.
 721  * "ideal" and "delta" should be constants, normally simple
 722  * integers, "value" a variable. Added to libpng-1.2.6 JB
 723  */
 724 #define PNG_OUT_OF_RANGE(value, ideal, delta) \
 725    ( (value) < (ideal)-(delta) || (value) > (ideal)+(delta) )
 726 
 727 /* Conversions between fixed and floating point, only defined if
 728  * required (to make sure the code doesn't accidentally use float
 729  * when it is supposedly disabled.)
 730  */
 731 #ifdef PNG_FLOATING_POINT_SUPPORTED
 732 /* The floating point conversion can't overflow, though it can and
 733  * does lose accuracy relative to the original fixed point value.
 734  * In practice this doesn't matter because png_fixed_point only
 735  * stores numbers with very low precision.  The png_ptr and s
 736  * arguments are unused by default but are there in case error
 737  * checking becomes a requirement.
 738  */
 739 #define png_float(png_ptr, fixed, s) (.00001 * (fixed))
 740 
 741 /* The fixed point conversion performs range checking and evaluates
 742  * its argument multiple times, so must be used with care.  The
 743  * range checking uses the PNG specification values for a signed
 744  * 32-bit fixed point value except that the values are deliberately
 745  * rounded-to-zero to an integral value - 21474 (21474.83 is roughly
 746  * (2^31-1) * 100000). 's' is a string that describes the value being
 747  * converted.
 748  *
 749  * NOTE: this macro will raise a png_error if the range check fails,
 750  * therefore it is normally only appropriate to use this on values
 751  * that come from API calls or other sources where an out of range
 752  * error indicates a programming error, not a data error!
 753  *
 754  * NOTE: by default this is off - the macro is not used - because the
 755  * function call saves a lot of code.
 756  */
 757 #ifdef PNG_FIXED_POINT_MACRO_SUPPORTED
 758 #define png_fixed(png_ptr, fp, s) ((fp) <= 21474 && (fp) >= -21474 ?\
 759     ((png_fixed_point)(100000 * (fp))) : (png_fixed_error(png_ptr, s),0))
 760 #endif
 761 /* else the corresponding function is defined below, inside the scope of the
 762  * cplusplus test.
 763  */
 764 #endif
 765 
 766 /* Constants for known chunk types.  If you need to add a chunk, define the name
 767  * here.  For historical reasons these constants have the form png_<name>; i.e.
 768  * the prefix is lower case.  Please use decimal values as the parameters to
 769  * match the ISO PNG specification and to avoid relying on the C locale
 770  * interpretation of character values.
 771  *
 772  * Prior to 1.5.6 these constants were strings, as of 1.5.6 png_uint_32 values
 773  * are computed and a new macro (PNG_STRING_FROM_CHUNK) added to allow a string
 774  * to be generated if required.
 775  *
 776  * PNG_32b correctly produces a value shifted by up to 24 bits, even on
 777  * architectures where (int) is only 16 bits.
 778  */
 779 #define PNG_32b(b,s) ((png_uint_32)(b) << (s))
 780 #define PNG_U32(b1,b2,b3,b4) \
 781    (PNG_32b(b1,24) | PNG_32b(b2,16) | PNG_32b(b3,8) | PNG_32b(b4,0))
 782 
 783 /* Constants for known chunk types.
 784  *
 785  * MAINTAINERS: If you need to add a chunk, define the name here.
 786  * For historical reasons these constants have the form png_<name>; i.e.
 787  * the prefix is lower case.  Please use decimal values as the parameters to
 788  * match the ISO PNG specification and to avoid relying on the C locale
 789  * interpretation of character values.  Please keep the list sorted.
 790  *
 791  * Notice that PNG_U32 is used to define a 32-bit value for the 4 byte chunk
 792  * type.  In fact the specification does not express chunk types this way,
 793  * however using a 32-bit value means that the chunk type can be read from the
 794  * stream using exactly the same code as used for a 32-bit unsigned value and
 795  * can be examined far more efficiently (using one arithmetic compare).
 796  *
 797  * Prior to 1.5.6 the chunk type constants were expressed as C strings.  The
 798  * libpng API still uses strings for 'unknown' chunks and a macro,
 799  * PNG_STRING_FROM_CHUNK, allows a string to be generated if required.  Notice
 800  * that for portable code numeric values must still be used; the string "IHDR"
 801  * is not portable and neither is PNG_U32('I', 'H', 'D', 'R').
 802  *
 803  * In 1.7.0 the definitions will be made public in png.h to avoid having to
 804  * duplicate the same definitions in application code.
 805  */
 806 #define png_IDAT PNG_U32( 73,  68,  65,  84)
 807 #define png_IEND PNG_U32( 73,  69,  78,  68)
 808 #define png_IHDR PNG_U32( 73,  72,  68,  82)
 809 #define png_PLTE PNG_U32( 80,  76,  84,  69)
 810 #define png_bKGD PNG_U32( 98,  75,  71,  68)
 811 #define png_cHRM PNG_U32( 99,  72,  82,  77)
 812 #define png_fRAc PNG_U32(102,  82,  65,  99) /* registered, not defined */
 813 #define png_gAMA PNG_U32(103,  65,  77,  65)
 814 #define png_gIFg PNG_U32(103,  73,  70, 103)
 815 #define png_gIFt PNG_U32(103,  73,  70, 116) /* deprecated */
 816 #define png_gIFx PNG_U32(103,  73,  70, 120)
 817 #define png_hIST PNG_U32(104,  73,  83,  84)
 818 #define png_iCCP PNG_U32(105,  67,  67,  80)
 819 #define png_iTXt PNG_U32(105,  84,  88, 116)
 820 #define png_oFFs PNG_U32(111,  70,  70, 115)
 821 #define png_pCAL PNG_U32(112,  67,  65,  76)
 822 #define png_pHYs PNG_U32(112,  72,  89, 115)
 823 #define png_sBIT PNG_U32(115,  66,  73,  84)
 824 #define png_sCAL PNG_U32(115,  67,  65,  76)
 825 #define png_sPLT PNG_U32(115,  80,  76,  84)
 826 #define png_sRGB PNG_U32(115,  82,  71,  66)
 827 #define png_sTER PNG_U32(115,  84,  69,  82)
 828 #define png_tEXt PNG_U32(116,  69,  88, 116)
 829 #define png_tIME PNG_U32(116,  73,  77,  69)
 830 #define png_tRNS PNG_U32(116,  82,  78,  83)
 831 #define png_zTXt PNG_U32(122,  84,  88, 116)
 832 
 833 /* The following will work on (signed char*) strings, whereas the get_uint_32
 834  * macro will fail on top-bit-set values because of the sign extension.
 835  */
 836 #define PNG_CHUNK_FROM_STRING(s)\
 837    PNG_U32(0xff & (s)[0], 0xff & (s)[1], 0xff & (s)[2], 0xff & (s)[3])
 838 
 839 /* This uses (char), not (png_byte) to avoid warnings on systems where (char) is
 840  * signed and the argument is a (char[])  This macro will fail miserably on
 841  * systems where (char) is more than 8 bits.
 842  */
 843 #define PNG_STRING_FROM_CHUNK(s,c)\
 844    (void)(((char*)(s))[0]=(char)(((c)>>24) & 0xff), \
 845    ((char*)(s))[1]=(char)(((c)>>16) & 0xff),\
 846    ((char*)(s))[2]=(char)(((c)>>8) & 0xff), \
 847    ((char*)(s))[3]=(char)((c & 0xff)))
 848 
 849 /* Do the same but terminate with a null character. */
 850 #define PNG_CSTRING_FROM_CHUNK(s,c)\
 851    (void)(PNG_STRING_FROM_CHUNK(s,c), ((char*)(s))[4] = 0)
 852 
 853 /* Test on flag values as defined in the spec (section 5.4): */
 854 #define PNG_CHUNK_ANCILLARY(c)   (1 & ((c) >> 29))
 855 #define PNG_CHUNK_CRITICAL(c)     (!PNG_CHUNK_ANCILLARY(c))
 856 #define PNG_CHUNK_PRIVATE(c)      (1 & ((c) >> 21))
 857 #define PNG_CHUNK_RESERVED(c)     (1 & ((c) >> 13))
 858 #define PNG_CHUNK_SAFE_TO_COPY(c) (1 & ((c) >>  5))
 859 
 860 /* Gamma values (new at libpng-1.5.4): */
 861 #define PNG_GAMMA_MAC_OLD 151724  /* Assume '1.8' is really 2.2/1.45! */
 862 #define PNG_GAMMA_MAC_INVERSE 65909
 863 #define PNG_GAMMA_sRGB_INVERSE 45455
 864 
 865 /* Almost everything below is C specific; the #defines above can be used in
 866  * non-C code (so long as it is C-preprocessed) the rest of this stuff cannot.
 867  */
 868 #ifndef PNG_VERSION_INFO_ONLY
 869 
 870 #include "pngstruct.h"
 871 #include "pnginfo.h"
 872 
 873 /* Validate the include paths - the include path used to generate pnglibconf.h
 874  * must match that used in the build, or we must be using pnglibconf.h.prebuilt:
 875  */
 876 #if PNG_ZLIB_VERNUM != 0 && PNG_ZLIB_VERNUM != ZLIB_VERNUM
 877 #  error ZLIB_VERNUM != PNG_ZLIB_VERNUM \
 878       "-I (include path) error: see the notes in pngpriv.h"
 879    /* This means that when pnglibconf.h was built the copy of zlib.h that it
 880     * used is not the same as the one being used here.  Because the build of
 881     * libpng makes decisions to use inflateInit2 and inflateReset2 based on the
 882     * zlib version number and because this affects handling of certain broken
 883     * PNG files the -I directives must match.
 884     *
 885     * The most likely explanation is that you passed a -I in CFLAGS. This will
 886     * not work; all the preprocessor directories and in particular all the -I
 887     * directives must be in CPPFLAGS.
 888     */
 889 #endif
 890 
 891 /* This is used for 16-bit gamma tables -- only the top level pointers are
 892  * const; this could be changed:
 893  */
 894 typedef const png_uint_16p * png_const_uint_16pp;
 895 
 896 /* Added to libpng-1.5.7: sRGB conversion tables */
 897 #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
 898    defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
 899 #ifdef PNG_SIMPLIFIED_READ_SUPPORTED
 900 PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_table, [256]);
 901    /* Convert from an sRGB encoded value 0..255 to a 16-bit linear value,
 902     * 0..65535.  This table gives the closest 16-bit answers (no errors).
 903     */
 904 #endif
 905 
 906 PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_base, [512]);
 907 PNG_INTERNAL_DATA(const png_byte, png_sRGB_delta, [512]);
 908 
 909 #define PNG_sRGB_FROM_LINEAR(linear) \
 910   ((png_byte)(0xff & ((png_sRGB_base[(linear)>>15] \
 911    + ((((linear) & 0x7fff)*png_sRGB_delta[(linear)>>15])>>12)) >> 8)))
 912    /* Given a value 'linear' in the range 0..255*65535 calculate the 8-bit sRGB
 913     * encoded value with maximum error 0.646365.  Note that the input is not a
 914     * 16-bit value; it has been multiplied by 255! */
 915 #endif /* SIMPLIFIED_READ/WRITE */
 916 
 917 
 918 /* Inhibit C++ name-mangling for libpng functions but not for system calls. */
 919 #ifdef __cplusplus
 920 extern "C" {
 921 #endif /* __cplusplus */
 922 
 923 /* Internal functions; these are not exported from a DLL however because they
 924  * are used within several of the C source files they have to be C extern.
 925  *
 926  * All of these functions must be declared with PNG_INTERNAL_FUNCTION.
 927  */
 928 
 929 /* Zlib support */
 930 #define PNG_UNEXPECTED_ZLIB_RETURN (-7)
 931 PNG_INTERNAL_FUNCTION(void, png_zstream_error,(png_structrp png_ptr, int ret),
 932    PNG_EMPTY);
 933    /* Used by the zlib handling functions to ensure that z_stream::msg is always
 934     * set before they return.
 935     */
 936 
 937 #ifdef PNG_WRITE_SUPPORTED
 938 PNG_INTERNAL_FUNCTION(void,png_free_buffer_list,(png_structrp png_ptr,
 939    png_compression_bufferp *list),PNG_EMPTY);
 940    /* Free the buffer list used by the compressed write code. */
 941 #endif
 942 
 943 #if defined(PNG_FLOATING_POINT_SUPPORTED) && \
 944    !defined(PNG_FIXED_POINT_MACRO_SUPPORTED) && \
 945    (defined(PNG_gAMA_SUPPORTED) || defined(PNG_cHRM_SUPPORTED) || \
 946    defined(PNG_sCAL_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) || \
 947    defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)) || \
 948    (defined(PNG_sCAL_SUPPORTED) && \
 949    defined(PNG_FLOATING_ARITHMETIC_SUPPORTED))
 950 PNG_INTERNAL_FUNCTION(png_fixed_point,png_fixed,(png_const_structrp png_ptr,
 951    double fp, png_const_charp text),PNG_EMPTY);
 952 #endif
 953 
 954 /* Check the user version string for compatibility, returns false if the version
 955  * numbers aren't compatible.
 956  */
 957 PNG_INTERNAL_FUNCTION(int,png_user_version_check,(png_structrp png_ptr,
 958    png_const_charp user_png_ver),PNG_EMPTY);
 959 
 960 /* Internal base allocator - no messages, NULL on failure to allocate.  This
 961  * does, however, call the application provided allocator and that could call
 962  * png_error (although that would be a bug in the application implementation.)
 963  */
 964 PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_base,(png_const_structrp png_ptr,
 965    png_alloc_size_t size),PNG_ALLOCATED);
 966 
 967 #if defined(PNG_TEXT_SUPPORTED) || defined(PNG_sPLT_SUPPORTED) ||\
 968    defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED)
 969 /* Internal array allocator, outputs no error or warning messages on failure,
 970  * just returns NULL.
 971  */
 972 PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_array,(png_const_structrp png_ptr,
 973    int nelements, size_t element_size),PNG_ALLOCATED);
 974 
 975 /* The same but an existing array is extended by add_elements.  This function
 976  * also memsets the new elements to 0 and copies the old elements.  The old
 977  * array is not freed or altered.
 978  */
 979 PNG_INTERNAL_FUNCTION(png_voidp,png_realloc_array,(png_const_structrp png_ptr,
 980    png_const_voidp array, int old_elements, int add_elements,
 981    size_t element_size),PNG_ALLOCATED);
 982 #endif /* text, sPLT or unknown chunks */
 983 
 984 /* Magic to create a struct when there is no struct to call the user supplied
 985  * memory allocators.  Because error handling has not been set up the memory
 986  * handlers can't safely call png_error, but this is an obscure and undocumented
 987  * restriction so libpng has to assume that the 'free' handler, at least, might
 988  * call png_error.
 989  */
 990 PNG_INTERNAL_FUNCTION(png_structp,png_create_png_struct,
 991    (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
 992     png_error_ptr warn_fn, png_voidp mem_ptr, png_malloc_ptr malloc_fn,
 993     png_free_ptr free_fn),PNG_ALLOCATED);
 994 
 995 /* Free memory from internal libpng struct */
 996 PNG_INTERNAL_FUNCTION(void,png_destroy_png_struct,(png_structrp png_ptr),
 997    PNG_EMPTY);
 998 
 999 /* Free an allocated jmp_buf (always succeeds) */
1000 PNG_INTERNAL_FUNCTION(void,png_free_jmpbuf,(png_structrp png_ptr),PNG_EMPTY);
1001 
1002 /* Function to allocate memory for zlib.  PNGAPI is disallowed. */
1003 PNG_INTERNAL_FUNCTION(voidpf,png_zalloc,(voidpf png_ptr, uInt items, uInt size),
1004    PNG_ALLOCATED);
1005 
1006 /* Function to free memory for zlib.  PNGAPI is disallowed. */
1007 PNG_INTERNAL_FUNCTION(void,png_zfree,(voidpf png_ptr, voidpf ptr),PNG_EMPTY);
1008 
1009 /* Next four functions are used internally as callbacks.  PNGCBAPI is required
1010  * but not PNG_EXPORT.  PNGAPI added at libpng version 1.2.3, changed to
1011  * PNGCBAPI at 1.5.0
1012  */
1013 
1014 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_read_data,(png_structp png_ptr,
1015     png_bytep data, png_size_t length),PNG_EMPTY);
1016 
1017 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1018 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_push_fill_buffer,(png_structp png_ptr,
1019     png_bytep buffer, png_size_t length),PNG_EMPTY);
1020 #endif
1021 
1022 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_write_data,(png_structp png_ptr,
1023     png_bytep data, png_size_t length),PNG_EMPTY);
1024 
1025 #ifdef PNG_WRITE_FLUSH_SUPPORTED
1026 #  ifdef PNG_STDIO_SUPPORTED
1027 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_flush,(png_structp png_ptr),
1028    PNG_EMPTY);
1029 #  endif
1030 #endif
1031 
1032 /* Reset the CRC variable */
1033 PNG_INTERNAL_FUNCTION(void,png_reset_crc,(png_structrp png_ptr),PNG_EMPTY);
1034 
1035 /* Write the "data" buffer to whatever output you are using */
1036 PNG_INTERNAL_FUNCTION(void,png_write_data,(png_structrp png_ptr,
1037     png_const_bytep data, png_size_t length),PNG_EMPTY);
1038 
1039 /* Read and check the PNG file signature */
1040 PNG_INTERNAL_FUNCTION(void,png_read_sig,(png_structrp png_ptr,
1041    png_inforp info_ptr),PNG_EMPTY);
1042 
1043 /* Read the chunk header (length + type name) */
1044 PNG_INTERNAL_FUNCTION(png_uint_32,png_read_chunk_header,(png_structrp png_ptr),
1045    PNG_EMPTY);
1046 
1047 /* Read data from whatever input you are using into the "data" buffer */
1048 PNG_INTERNAL_FUNCTION(void,png_read_data,(png_structrp png_ptr, png_bytep data,
1049     png_size_t length),PNG_EMPTY);
1050 
1051 /* Read bytes into buf, and update png_ptr->crc */
1052 PNG_INTERNAL_FUNCTION(void,png_crc_read,(png_structrp png_ptr, png_bytep buf,
1053     png_uint_32 length),PNG_EMPTY);
1054 
1055 /* Read "skip" bytes, read the file crc, and (optionally) verify png_ptr->crc */
1056 PNG_INTERNAL_FUNCTION(int,png_crc_finish,(png_structrp png_ptr,
1057    png_uint_32 skip),PNG_EMPTY);
1058 
1059 /* Read the CRC from the file and compare it to the libpng calculated CRC */
1060 PNG_INTERNAL_FUNCTION(int,png_crc_error,(png_structrp png_ptr),PNG_EMPTY);
1061 
1062 /* Calculate the CRC over a section of data.  Note that we are only
1063  * passing a maximum of 64K on systems that have this as a memory limit,
1064  * since this is the maximum buffer size we can specify.
1065  */
1066 PNG_INTERNAL_FUNCTION(void,png_calculate_crc,(png_structrp png_ptr,
1067    png_const_bytep ptr, png_size_t length),PNG_EMPTY);
1068 
1069 #ifdef PNG_WRITE_FLUSH_SUPPORTED
1070 PNG_INTERNAL_FUNCTION(void,png_flush,(png_structrp png_ptr),PNG_EMPTY);
1071 #endif
1072 
1073 /* Write various chunks */
1074 
1075 /* Write the IHDR chunk, and update the png_struct with the necessary
1076  * information.
1077  */
1078 PNG_INTERNAL_FUNCTION(void,png_write_IHDR,(png_structrp png_ptr,
1079    png_uint_32 width, png_uint_32 height, int bit_depth, int color_type,
1080    int compression_method, int filter_method, int interlace_method),PNG_EMPTY);
1081 
1082 PNG_INTERNAL_FUNCTION(void,png_write_PLTE,(png_structrp png_ptr,
1083    png_const_colorp palette, png_uint_32 num_pal),PNG_EMPTY);
1084 
1085 PNG_INTERNAL_FUNCTION(void,png_compress_IDAT,(png_structrp png_ptr,
1086    png_const_bytep row_data, png_alloc_size_t row_data_length, int flush),
1087    PNG_EMPTY);
1088 
1089 PNG_INTERNAL_FUNCTION(void,png_write_IEND,(png_structrp png_ptr),PNG_EMPTY);
1090 
1091 #ifdef PNG_WRITE_gAMA_SUPPORTED
1092 PNG_INTERNAL_FUNCTION(void,png_write_gAMA_fixed,(png_structrp png_ptr,
1093     png_fixed_point file_gamma),PNG_EMPTY);
1094 #endif
1095 
1096 #ifdef PNG_WRITE_sBIT_SUPPORTED
1097 PNG_INTERNAL_FUNCTION(void,png_write_sBIT,(png_structrp png_ptr,
1098     png_const_color_8p sbit, int color_type),PNG_EMPTY);
1099 #endif
1100 
1101 #ifdef PNG_WRITE_cHRM_SUPPORTED
1102 PNG_INTERNAL_FUNCTION(void,png_write_cHRM_fixed,(png_structrp png_ptr,
1103     const png_xy *xy), PNG_EMPTY);
1104    /* The xy value must have been previously validated */
1105 #endif
1106 
1107 #ifdef PNG_WRITE_sRGB_SUPPORTED
1108 PNG_INTERNAL_FUNCTION(void,png_write_sRGB,(png_structrp png_ptr,
1109     int intent),PNG_EMPTY);
1110 #endif
1111 
1112 #ifdef PNG_WRITE_iCCP_SUPPORTED
1113 PNG_INTERNAL_FUNCTION(void,png_write_iCCP,(png_structrp png_ptr,
1114    png_const_charp name, png_const_bytep profile), PNG_EMPTY);
1115    /* The profile must have been previously validated for correctness, the
1116     * length comes from the first four bytes.  Only the base, deflate,
1117     * compression is supported.
1118     */
1119 #endif
1120 
1121 #ifdef PNG_WRITE_sPLT_SUPPORTED
1122 PNG_INTERNAL_FUNCTION(void,png_write_sPLT,(png_structrp png_ptr,
1123     png_const_sPLT_tp palette),PNG_EMPTY);
1124 #endif
1125 
1126 #ifdef PNG_WRITE_tRNS_SUPPORTED
1127 PNG_INTERNAL_FUNCTION(void,png_write_tRNS,(png_structrp png_ptr,
1128     png_const_bytep trans, png_const_color_16p values, int number,
1129     int color_type),PNG_EMPTY);
1130 #endif
1131 
1132 #ifdef PNG_WRITE_bKGD_SUPPORTED
1133 PNG_INTERNAL_FUNCTION(void,png_write_bKGD,(png_structrp png_ptr,
1134     png_const_color_16p values, int color_type),PNG_EMPTY);
1135 #endif
1136 
1137 #ifdef PNG_WRITE_hIST_SUPPORTED
1138 PNG_INTERNAL_FUNCTION(void,png_write_hIST,(png_structrp png_ptr,
1139     png_const_uint_16p hist, int num_hist),PNG_EMPTY);
1140 #endif
1141 
1142 /* Chunks that have keywords */
1143 #ifdef PNG_WRITE_tEXt_SUPPORTED
1144 PNG_INTERNAL_FUNCTION(void,png_write_tEXt,(png_structrp png_ptr,
1145    png_const_charp key, png_const_charp text, png_size_t text_len),PNG_EMPTY);
1146 #endif
1147 
1148 #ifdef PNG_WRITE_zTXt_SUPPORTED
1149 PNG_INTERNAL_FUNCTION(void,png_write_zTXt,(png_structrp png_ptr, png_const_charp
1150     key, png_const_charp text, int compression),PNG_EMPTY);
1151 #endif
1152 
1153 #ifdef PNG_WRITE_iTXt_SUPPORTED
1154 PNG_INTERNAL_FUNCTION(void,png_write_iTXt,(png_structrp png_ptr,
1155     int compression, png_const_charp key, png_const_charp lang,
1156     png_const_charp lang_key, png_const_charp text),PNG_EMPTY);
1157 #endif
1158 
1159 #ifdef PNG_TEXT_SUPPORTED  /* Added at version 1.0.14 and 1.2.4 */
1160 PNG_INTERNAL_FUNCTION(int,png_set_text_2,(png_const_structrp png_ptr,
1161     png_inforp info_ptr, png_const_textp text_ptr, int num_text),PNG_EMPTY);
1162 #endif
1163 
1164 #ifdef PNG_WRITE_oFFs_SUPPORTED
1165 PNG_INTERNAL_FUNCTION(void,png_write_oFFs,(png_structrp png_ptr,
1166     png_int_32 x_offset, png_int_32 y_offset, int unit_type),PNG_EMPTY);
1167 #endif
1168 
1169 #ifdef PNG_WRITE_pCAL_SUPPORTED
1170 PNG_INTERNAL_FUNCTION(void,png_write_pCAL,(png_structrp png_ptr,
1171     png_charp purpose, png_int_32 X0, png_int_32 X1, int type, int nparams,
1172     png_const_charp units, png_charpp params),PNG_EMPTY);
1173 #endif
1174 
1175 #ifdef PNG_WRITE_pHYs_SUPPORTED
1176 PNG_INTERNAL_FUNCTION(void,png_write_pHYs,(png_structrp png_ptr,
1177     png_uint_32 x_pixels_per_unit, png_uint_32 y_pixels_per_unit,
1178     int unit_type),PNG_EMPTY);
1179 #endif
1180 
1181 #ifdef PNG_WRITE_tIME_SUPPORTED
1182 PNG_INTERNAL_FUNCTION(void,png_write_tIME,(png_structrp png_ptr,
1183     png_const_timep mod_time),PNG_EMPTY);
1184 #endif
1185 
1186 #ifdef PNG_WRITE_sCAL_SUPPORTED
1187 PNG_INTERNAL_FUNCTION(void,png_write_sCAL_s,(png_structrp png_ptr,
1188     int unit, png_const_charp width, png_const_charp height),PNG_EMPTY);
1189 #endif
1190 
1191 /* Called when finished processing a row of data */
1192 PNG_INTERNAL_FUNCTION(void,png_write_finish_row,(png_structrp png_ptr),
1193     PNG_EMPTY);
1194 
1195 /* Internal use only.   Called before first row of data */
1196 PNG_INTERNAL_FUNCTION(void,png_write_start_row,(png_structrp png_ptr),
1197     PNG_EMPTY);
1198 
1199 /* Combine a row of data, dealing with alpha, etc. if requested.  'row' is an
1200  * array of png_ptr->width pixels.  If the image is not interlaced or this
1201  * is the final pass this just does a memcpy, otherwise the "display" flag
1202  * is used to determine whether to copy pixels that are not in the current pass.
1203  *
1204  * Because 'png_do_read_interlace' (below) replicates pixels this allows this
1205  * function to achieve the documented 'blocky' appearance during interlaced read
1206  * if display is 1 and the 'sparkle' appearance, where existing pixels in 'row'
1207  * are not changed if they are not in the current pass, when display is 0.
1208  *
1209  * 'display' must be 0 or 1, otherwise the memcpy will be done regardless.
1210  *
1211  * The API always reads from the png_struct row buffer and always assumes that
1212  * it is full width (png_do_read_interlace has already been called.)
1213  *
1214  * This function is only ever used to write to row buffers provided by the
1215  * caller of the relevant libpng API and the row must have already been
1216  * transformed by the read transformations.
1217  *
1218  * The PNG_USE_COMPILE_TIME_MASKS option causes generation of pre-computed
1219  * bitmasks for use within the code, otherwise runtime generated masks are used.
1220  * The default is compile time masks.
1221  */
1222 #ifndef PNG_USE_COMPILE_TIME_MASKS
1223 #  define PNG_USE_COMPILE_TIME_MASKS 1
1224 #endif
1225 PNG_INTERNAL_FUNCTION(void,png_combine_row,(png_const_structrp png_ptr,
1226     png_bytep row, int display),PNG_EMPTY);
1227 
1228 #ifdef PNG_READ_INTERLACING_SUPPORTED
1229 /* Expand an interlaced row: the 'row_info' describes the pass data that has
1230  * been read in and must correspond to the pixels in 'row', the pixels are
1231  * expanded (moved apart) in 'row' to match the final layout, when doing this
1232  * the pixels are *replicated* to the intervening space.  This is essential for
1233  * the correct operation of png_combine_row, above.
1234  */
1235 PNG_INTERNAL_FUNCTION(void,png_do_read_interlace,(png_row_infop row_info,
1236     png_bytep row, int pass, png_uint_32 transformations),PNG_EMPTY);
1237 #endif
1238 
1239 /* GRR TO DO (2.0 or whenever):  simplify other internal calling interfaces */
1240 
1241 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1242 /* Grab pixels out of a row for an interlaced pass */
1243 PNG_INTERNAL_FUNCTION(void,png_do_write_interlace,(png_row_infop row_info,
1244     png_bytep row, int pass),PNG_EMPTY);
1245 #endif
1246 
1247 /* Unfilter a row: check the filter value before calling this, there is no point
1248  * calling it for PNG_FILTER_VALUE_NONE.
1249  */
1250 PNG_INTERNAL_FUNCTION(void,png_read_filter_row,(png_structrp pp, png_row_infop
1251     row_info, png_bytep row, png_const_bytep prev_row, int filter),PNG_EMPTY);
1252 
1253 #if PNG_ARM_NEON_OPT > 0
1254 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_up_neon,(png_row_infop row_info,
1255     png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1256 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_neon,(png_row_infop
1257     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1258 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_neon,(png_row_infop
1259     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1260 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_neon,(png_row_infop
1261     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1262 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_neon,(png_row_infop
1263     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1264 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_neon,(png_row_infop
1265     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1266 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_neon,(png_row_infop
1267     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1268 #endif
1269 
1270 #if PNG_MIPS_MSA_OPT > 0
1271 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_up_msa,(png_row_infop row_info,
1272     png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1273 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_msa,(png_row_infop
1274     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1275 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_msa,(png_row_infop
1276     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1277 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_msa,(png_row_infop
1278     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1279 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_msa,(png_row_infop
1280     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1281 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_msa,(png_row_infop
1282     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1283 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_msa,(png_row_infop
1284     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1285 #endif
1286 
1287 /* Choose the best filter to use and filter the row data */
1288 PNG_INTERNAL_FUNCTION(void,png_write_find_filter,(png_structrp png_ptr,
1289     png_row_infop row_info),PNG_EMPTY);
1290 
1291 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1292 PNG_INTERNAL_FUNCTION(void,png_read_IDAT_data,(png_structrp png_ptr,
1293    png_bytep output, png_alloc_size_t avail_out),PNG_EMPTY);
1294    /* Read 'avail_out' bytes of data from the IDAT stream.  If the output buffer
1295     * is NULL the function checks, instead, for the end of the stream.  In this
1296     * case a benign error will be issued if the stream end is not found or if
1297     * extra data has to be consumed.
1298     */
1299 PNG_INTERNAL_FUNCTION(void,png_read_finish_IDAT,(png_structrp png_ptr),
1300    PNG_EMPTY);
1301    /* This cleans up when the IDAT LZ stream does not end when the last image
1302     * byte is read; there is still some pending input.
1303     */
1304 
1305 PNG_INTERNAL_FUNCTION(void,png_read_finish_row,(png_structrp png_ptr),
1306    PNG_EMPTY);
1307    /* Finish a row while reading, dealing with interlacing passes, etc. */
1308 #endif /* SEQUENTIAL_READ */
1309 
1310 /* Initialize the row buffers, etc. */
1311 PNG_INTERNAL_FUNCTION(void,png_read_start_row,(png_structrp png_ptr),PNG_EMPTY);
1312 
1313 #if ZLIB_VERNUM >= 0x1240
1314 PNG_INTERNAL_FUNCTION(int,png_zlib_inflate,(png_structrp png_ptr, int flush),
1315       PNG_EMPTY);
1316 #  define PNG_INFLATE(pp, flush) png_zlib_inflate(pp, flush)
1317 #else /* Zlib < 1.2.4 */
1318 #  define PNG_INFLATE(pp, flush) inflate(&(pp)->zstream, flush)
1319 #endif /* Zlib < 1.2.4 */
1320 
1321 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1322 /* Optional call to update the users info structure */
1323 PNG_INTERNAL_FUNCTION(void,png_read_transform_info,(png_structrp png_ptr,
1324     png_inforp info_ptr),PNG_EMPTY);
1325 #endif
1326 
1327 /* Shared transform functions, defined in pngtran.c */
1328 #if defined(PNG_WRITE_FILLER_SUPPORTED) || \
1329     defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
1330 PNG_INTERNAL_FUNCTION(void,png_do_strip_channel,(png_row_infop row_info,
1331     png_bytep row, int at_start),PNG_EMPTY);
1332 #endif
1333 
1334 #ifdef PNG_16BIT_SUPPORTED
1335 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
1336 PNG_INTERNAL_FUNCTION(void,png_do_swap,(png_row_infop row_info,
1337     png_bytep row),PNG_EMPTY);
1338 #endif
1339 #endif
1340 
1341 #if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
1342     defined(PNG_WRITE_PACKSWAP_SUPPORTED)
1343 PNG_INTERNAL_FUNCTION(void,png_do_packswap,(png_row_infop row_info,
1344     png_bytep row),PNG_EMPTY);
1345 #endif
1346 
1347 #if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
1348 PNG_INTERNAL_FUNCTION(void,png_do_invert,(png_row_infop row_info,
1349     png_bytep row),PNG_EMPTY);
1350 #endif
1351 
1352 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
1353 PNG_INTERNAL_FUNCTION(void,png_do_bgr,(png_row_infop row_info,
1354     png_bytep row),PNG_EMPTY);
1355 #endif
1356 
1357 /* The following decodes the appropriate chunks, and does error correction,
1358  * then calls the appropriate callback for the chunk if it is valid.
1359  */
1360 
1361 /* Decode the IHDR chunk */
1362 PNG_INTERNAL_FUNCTION(void,png_handle_IHDR,(png_structrp png_ptr,
1363     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1364 PNG_INTERNAL_FUNCTION(void,png_handle_PLTE,(png_structrp png_ptr,
1365     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1366 PNG_INTERNAL_FUNCTION(void,png_handle_IEND,(png_structrp png_ptr,
1367     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1368 
1369 #ifdef PNG_READ_bKGD_SUPPORTED
1370 PNG_INTERNAL_FUNCTION(void,png_handle_bKGD,(png_structrp png_ptr,
1371     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1372 #endif
1373 
1374 #ifdef PNG_READ_cHRM_SUPPORTED
1375 PNG_INTERNAL_FUNCTION(void,png_handle_cHRM,(png_structrp png_ptr,
1376     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1377 #endif
1378 
1379 #ifdef PNG_READ_gAMA_SUPPORTED
1380 PNG_INTERNAL_FUNCTION(void,png_handle_gAMA,(png_structrp png_ptr,
1381     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1382 #endif
1383 
1384 #ifdef PNG_READ_hIST_SUPPORTED
1385 PNG_INTERNAL_FUNCTION(void,png_handle_hIST,(png_structrp png_ptr,
1386     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1387 #endif
1388 
1389 #ifdef PNG_READ_iCCP_SUPPORTED
1390 PNG_INTERNAL_FUNCTION(void,png_handle_iCCP,(png_structrp png_ptr,
1391     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1392 #endif /* READ_iCCP */
1393 
1394 #ifdef PNG_READ_iTXt_SUPPORTED
1395 PNG_INTERNAL_FUNCTION(void,png_handle_iTXt,(png_structrp png_ptr,
1396     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1397 #endif
1398 
1399 #ifdef PNG_READ_oFFs_SUPPORTED
1400 PNG_INTERNAL_FUNCTION(void,png_handle_oFFs,(png_structrp png_ptr,
1401     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1402 #endif
1403 
1404 #ifdef PNG_READ_pCAL_SUPPORTED
1405 PNG_INTERNAL_FUNCTION(void,png_handle_pCAL,(png_structrp png_ptr,
1406     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1407 #endif
1408 
1409 #ifdef PNG_READ_pHYs_SUPPORTED
1410 PNG_INTERNAL_FUNCTION(void,png_handle_pHYs,(png_structrp png_ptr,
1411     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1412 #endif
1413 
1414 #ifdef PNG_READ_sBIT_SUPPORTED
1415 PNG_INTERNAL_FUNCTION(void,png_handle_sBIT,(png_structrp png_ptr,
1416     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1417 #endif
1418 
1419 #ifdef PNG_READ_sCAL_SUPPORTED
1420 PNG_INTERNAL_FUNCTION(void,png_handle_sCAL,(png_structrp png_ptr,
1421     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1422 #endif
1423 
1424 #ifdef PNG_READ_sPLT_SUPPORTED
1425 PNG_INTERNAL_FUNCTION(void,png_handle_sPLT,(png_structrp png_ptr,
1426     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1427 #endif /* READ_sPLT */
1428 
1429 #ifdef PNG_READ_sRGB_SUPPORTED
1430 PNG_INTERNAL_FUNCTION(void,png_handle_sRGB,(png_structrp png_ptr,
1431     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1432 #endif
1433 
1434 #ifdef PNG_READ_tEXt_SUPPORTED
1435 PNG_INTERNAL_FUNCTION(void,png_handle_tEXt,(png_structrp png_ptr,
1436     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1437 #endif
1438 
1439 #ifdef PNG_READ_tIME_SUPPORTED
1440 PNG_INTERNAL_FUNCTION(void,png_handle_tIME,(png_structrp png_ptr,
1441     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1442 #endif
1443 
1444 #ifdef PNG_READ_tRNS_SUPPORTED
1445 PNG_INTERNAL_FUNCTION(void,png_handle_tRNS,(png_structrp png_ptr,
1446     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1447 #endif
1448 
1449 #ifdef PNG_READ_zTXt_SUPPORTED
1450 PNG_INTERNAL_FUNCTION(void,png_handle_zTXt,(png_structrp png_ptr,
1451     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1452 #endif
1453 
1454 PNG_INTERNAL_FUNCTION(void,png_check_chunk_name,(png_structrp png_ptr,
1455     png_uint_32 chunk_name),PNG_EMPTY);
1456 
1457 PNG_INTERNAL_FUNCTION(void,png_handle_unknown,(png_structrp png_ptr,
1458     png_inforp info_ptr, png_uint_32 length, int keep),PNG_EMPTY);
1459    /* This is the function that gets called for unknown chunks.  The 'keep'
1460     * argument is either non-zero for a known chunk that has been set to be
1461     * handled as unknown or zero for an unknown chunk.  By default the function
1462     * just skips the chunk or errors out if it is critical.
1463     */
1464 
1465 #if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) ||\
1466     defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
1467 PNG_INTERNAL_FUNCTION(int,png_chunk_unknown_handling,
1468     (png_const_structrp png_ptr, png_uint_32 chunk_name),PNG_EMPTY);
1469    /* Exactly as the API png_handle_as_unknown() except that the argument is a
1470     * 32-bit chunk name, not a string.
1471     */
1472 #endif /* READ_UNKNOWN_CHUNKS || HANDLE_AS_UNKNOWN */
1473 
1474 /* Handle the transformations for reading and writing */
1475 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1476 PNG_INTERNAL_FUNCTION(void,png_do_read_transformations,(png_structrp png_ptr,
1477    png_row_infop row_info),PNG_EMPTY);
1478 #endif
1479 #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
1480 PNG_INTERNAL_FUNCTION(void,png_do_write_transformations,(png_structrp png_ptr,
1481    png_row_infop row_info),PNG_EMPTY);
1482 #endif
1483 
1484 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1485 PNG_INTERNAL_FUNCTION(void,png_init_read_transformations,(png_structrp png_ptr),
1486     PNG_EMPTY);
1487 #endif
1488 
1489 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1490 PNG_INTERNAL_FUNCTION(void,png_push_read_chunk,(png_structrp png_ptr,
1491     png_inforp info_ptr),PNG_EMPTY);
1492 PNG_INTERNAL_FUNCTION(void,png_push_read_sig,(png_structrp png_ptr,
1493     png_inforp info_ptr),PNG_EMPTY);
1494 PNG_INTERNAL_FUNCTION(void,png_push_check_crc,(png_structrp png_ptr),PNG_EMPTY);
1495 PNG_INTERNAL_FUNCTION(void,png_push_save_buffer,(png_structrp png_ptr),
1496     PNG_EMPTY);
1497 PNG_INTERNAL_FUNCTION(void,png_push_restore_buffer,(png_structrp png_ptr,
1498     png_bytep buffer, png_size_t buffer_length),PNG_EMPTY);
1499 PNG_INTERNAL_FUNCTION(void,png_push_read_IDAT,(png_structrp png_ptr),PNG_EMPTY);
1500 PNG_INTERNAL_FUNCTION(void,png_process_IDAT_data,(png_structrp png_ptr,
1501     png_bytep buffer, png_size_t buffer_length),PNG_EMPTY);
1502 PNG_INTERNAL_FUNCTION(void,png_push_process_row,(png_structrp png_ptr),
1503     PNG_EMPTY);
1504 PNG_INTERNAL_FUNCTION(void,png_push_handle_unknown,(png_structrp png_ptr,
1505    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1506 PNG_INTERNAL_FUNCTION(void,png_push_have_info,(png_structrp png_ptr,
1507    png_inforp info_ptr),PNG_EMPTY);
1508 PNG_INTERNAL_FUNCTION(void,png_push_have_end,(png_structrp png_ptr,
1509    png_inforp info_ptr),PNG_EMPTY);
1510 PNG_INTERNAL_FUNCTION(void,png_push_have_row,(png_structrp png_ptr,
1511     png_bytep row),PNG_EMPTY);
1512 PNG_INTERNAL_FUNCTION(void,png_push_read_end,(png_structrp png_ptr,
1513     png_inforp info_ptr),PNG_EMPTY);
1514 PNG_INTERNAL_FUNCTION(void,png_process_some_data,(png_structrp png_ptr,
1515     png_inforp info_ptr),PNG_EMPTY);
1516 PNG_INTERNAL_FUNCTION(void,png_read_push_finish_row,(png_structrp png_ptr),
1517     PNG_EMPTY);
1518 #  ifdef PNG_READ_tEXt_SUPPORTED
1519 PNG_INTERNAL_FUNCTION(void,png_push_handle_tEXt,(png_structrp png_ptr,
1520     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1521 PNG_INTERNAL_FUNCTION(void,png_push_read_tEXt,(png_structrp png_ptr,
1522     png_inforp info_ptr),PNG_EMPTY);
1523 #  endif
1524 #  ifdef PNG_READ_zTXt_SUPPORTED
1525 PNG_INTERNAL_FUNCTION(void,png_push_handle_zTXt,(png_structrp png_ptr,
1526     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1527 PNG_INTERNAL_FUNCTION(void,png_push_read_zTXt,(png_structrp png_ptr,
1528     png_inforp info_ptr),PNG_EMPTY);
1529 #  endif
1530 #  ifdef PNG_READ_iTXt_SUPPORTED
1531 PNG_INTERNAL_FUNCTION(void,png_push_handle_iTXt,(png_structrp png_ptr,
1532     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1533 PNG_INTERNAL_FUNCTION(void,png_push_read_iTXt,(png_structrp png_ptr,
1534     png_inforp info_ptr),PNG_EMPTY);
1535 #  endif
1536 
1537 #endif /* PROGRESSIVE_READ */
1538 
1539 /* Added at libpng version 1.6.0 */
1540 #ifdef PNG_GAMMA_SUPPORTED
1541 PNG_INTERNAL_FUNCTION(void,png_colorspace_set_gamma,(png_const_structrp png_ptr,
1542     png_colorspacerp colorspace, png_fixed_point gAMA), PNG_EMPTY);
1543    /* Set the colorspace gamma with a value provided by the application or by
1544     * the gAMA chunk on read.  The value will override anything set by an ICC
1545     * profile.
1546     */
1547 
1548 PNG_INTERNAL_FUNCTION(void,png_colorspace_sync_info,(png_const_structrp png_ptr,
1549     png_inforp info_ptr), PNG_EMPTY);
1550    /* Synchronize the info 'valid' flags with the colorspace */
1551 
1552 PNG_INTERNAL_FUNCTION(void,png_colorspace_sync,(png_const_structrp png_ptr,
1553     png_inforp info_ptr), PNG_EMPTY);
1554    /* Copy the png_struct colorspace to the info_struct and call the above to
1555     * synchronize the flags.  Checks for NULL info_ptr and does nothing.
1556     */
1557 #endif
1558 
1559 /* Added at libpng version 1.4.0 */
1560 #ifdef PNG_COLORSPACE_SUPPORTED
1561 /* These internal functions are for maintaining the colorspace structure within
1562  * a png_info or png_struct (or, indeed, both).
1563  */
1564 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_chromaticities,
1565    (png_const_structrp png_ptr, png_colorspacerp colorspace, const png_xy *xy,
1566     int preferred), PNG_EMPTY);
1567 
1568 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_endpoints,
1569    (png_const_structrp png_ptr, png_colorspacerp colorspace, const png_XYZ *XYZ,
1570     int preferred), PNG_EMPTY);
1571 
1572 #ifdef PNG_sRGB_SUPPORTED
1573 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_sRGB,(png_const_structrp png_ptr,
1574    png_colorspacerp colorspace, int intent), PNG_EMPTY);
1575    /* This does set the colorspace gAMA and cHRM values too, but doesn't set the
1576     * flags to write them, if it returns false there was a problem and an error
1577     * message has already been output (but the colorspace may still need to be
1578     * synced to record the invalid flag).
1579     */
1580 #endif /* sRGB */
1581 
1582 #ifdef PNG_iCCP_SUPPORTED
1583 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_ICC,(png_const_structrp png_ptr,
1584    png_colorspacerp colorspace, png_const_charp name,
1585    png_uint_32 profile_length, png_const_bytep profile, int color_type),
1586    PNG_EMPTY);
1587    /* The 'name' is used for information only */
1588 
1589 /* Routines for checking parts of an ICC profile. */
1590 #ifdef PNG_READ_iCCP_SUPPORTED
1591 PNG_INTERNAL_FUNCTION(int,png_icc_check_length,(png_const_structrp png_ptr,
1592    png_colorspacerp colorspace, png_const_charp name,
1593    png_uint_32 profile_length), PNG_EMPTY);
1594 #endif /* READ_iCCP */
1595 PNG_INTERNAL_FUNCTION(int,png_icc_check_header,(png_const_structrp png_ptr,
1596    png_colorspacerp colorspace, png_const_charp name,
1597    png_uint_32 profile_length,
1598    png_const_bytep profile /* first 132 bytes only */, int color_type),
1599    PNG_EMPTY);
1600 PNG_INTERNAL_FUNCTION(int,png_icc_check_tag_table,(png_const_structrp png_ptr,
1601    png_colorspacerp colorspace, png_const_charp name,
1602    png_uint_32 profile_length,
1603    png_const_bytep profile /* header plus whole tag table */), PNG_EMPTY);
1604 #ifdef PNG_sRGB_SUPPORTED
1605 PNG_INTERNAL_FUNCTION(void,png_icc_set_sRGB,(
1606    png_const_structrp png_ptr, png_colorspacerp colorspace,
1607    png_const_bytep profile, uLong adler), PNG_EMPTY);
1608    /* 'adler' is the Adler32 checksum of the uncompressed profile data. It may
1609     * be zero to indicate that it is not available.  It is used, if provided,
1610     * as a fast check on the profile when checking to see if it is sRGB.
1611     */
1612 #endif
1613 #endif /* iCCP */
1614 
1615 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1616 PNG_INTERNAL_FUNCTION(void,png_colorspace_set_rgb_coefficients,
1617    (png_structrp png_ptr), PNG_EMPTY);
1618    /* Set the rgb_to_gray coefficients from the colorspace Y values */
1619 #endif /* READ_RGB_TO_GRAY */
1620 #endif /* COLORSPACE */
1621 
1622 /* Added at libpng version 1.4.0 */
1623 PNG_INTERNAL_FUNCTION(void,png_check_IHDR,(png_const_structrp png_ptr,
1624     png_uint_32 width, png_uint_32 height, int bit_depth,
1625     int color_type, int interlace_type, int compression_type,
1626     int filter_type),PNG_EMPTY);
1627 
1628 /* Added at libpng version 1.5.10 */
1629 #if defined(PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED) || \
1630     defined(PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED)
1631 PNG_INTERNAL_FUNCTION(void,png_do_check_palette_indexes,
1632    (png_structrp png_ptr, png_row_infop row_info),PNG_EMPTY);
1633 #endif
1634 
1635 #if defined(PNG_FLOATING_POINT_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED)
1636 PNG_INTERNAL_FUNCTION(void,png_fixed_error,(png_const_structrp png_ptr,
1637    png_const_charp name),PNG_NORETURN);
1638 #endif
1639 
1640 /* Puts 'string' into 'buffer' at buffer[pos], taking care never to overwrite
1641  * the end.  Always leaves the buffer nul terminated.  Never errors out (and
1642  * there is no error code.)
1643  */
1644 PNG_INTERNAL_FUNCTION(size_t,png_safecat,(png_charp buffer, size_t bufsize,
1645    size_t pos, png_const_charp string),PNG_EMPTY);
1646 
1647 /* Various internal functions to handle formatted warning messages, currently
1648  * only implemented for warnings.
1649  */
1650 #if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_TIME_RFC1123_SUPPORTED)
1651 /* Utility to dump an unsigned value into a buffer, given a start pointer and
1652  * and end pointer (which should point just *beyond* the end of the buffer!)
1653  * Returns the pointer to the start of the formatted string.  This utility only
1654  * does unsigned values.
1655  */
1656 PNG_INTERNAL_FUNCTION(png_charp,png_format_number,(png_const_charp start,
1657    png_charp end, int format, png_alloc_size_t number),PNG_EMPTY);
1658 
1659 /* Convenience macro that takes an array: */
1660 #define PNG_FORMAT_NUMBER(buffer,format,number) \
1661    png_format_number(buffer, buffer + (sizeof buffer), format, number)
1662 
1663 /* Suggested size for a number buffer (enough for 64 bits and a sign!) */
1664 #define PNG_NUMBER_BUFFER_SIZE 24
1665 
1666 /* These are the integer formats currently supported, the name is formed from
1667  * the standard printf(3) format string.
1668  */
1669 #define PNG_NUMBER_FORMAT_u     1 /* chose unsigned API! */
1670 #define PNG_NUMBER_FORMAT_02u   2
1671 #define PNG_NUMBER_FORMAT_d     1 /* chose signed API! */
1672 #define PNG_NUMBER_FORMAT_02d   2
1673 #define PNG_NUMBER_FORMAT_x     3
1674 #define PNG_NUMBER_FORMAT_02x   4
1675 #define PNG_NUMBER_FORMAT_fixed 5 /* choose the signed API */
1676 #endif
1677 
1678 #ifdef PNG_WARNINGS_SUPPORTED
1679 /* New defines and members adding in libpng-1.5.4 */
1680 #  define PNG_WARNING_PARAMETER_SIZE 32
1681 #  define PNG_WARNING_PARAMETER_COUNT 8 /* Maximum 9; see pngerror.c */
1682 
1683 /* An l-value of this type has to be passed to the APIs below to cache the
1684  * values of the parameters to a formatted warning message.
1685  */
1686 typedef char png_warning_parameters[PNG_WARNING_PARAMETER_COUNT][
1687    PNG_WARNING_PARAMETER_SIZE];
1688 
1689 PNG_INTERNAL_FUNCTION(void,png_warning_parameter,(png_warning_parameters p,
1690    int number, png_const_charp string),PNG_EMPTY);
1691    /* Parameters are limited in size to PNG_WARNING_PARAMETER_SIZE characters,
1692     * including the trailing '\0'.
1693     */
1694 PNG_INTERNAL_FUNCTION(void,png_warning_parameter_unsigned,
1695    (png_warning_parameters p, int number, int format, png_alloc_size_t value),
1696    PNG_EMPTY);
1697    /* Use png_alloc_size_t because it is an unsigned type as big as any we
1698     * need to output.  Use the following for a signed value.
1699     */
1700 PNG_INTERNAL_FUNCTION(void,png_warning_parameter_signed,
1701    (png_warning_parameters p, int number, int format, png_int_32 value),
1702    PNG_EMPTY);
1703 
1704 PNG_INTERNAL_FUNCTION(void,png_formatted_warning,(png_const_structrp png_ptr,
1705    png_warning_parameters p, png_const_charp message),PNG_EMPTY);
1706    /* 'message' follows the X/Open approach of using @1, @2 to insert
1707     * parameters previously supplied using the above functions.  Errors in
1708     * specifying the parameters will simply result in garbage substitutions.
1709     */
1710 #endif
1711 
1712 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
1713 /* Application errors (new in 1.6); use these functions (declared below) for
1714  * errors in the parameters or order of API function calls on read.  The
1715  * 'warning' should be used for an error that can be handled completely; the
1716  * 'error' for one which can be handled safely but which may lose application
1717  * information or settings.
1718  *
1719  * By default these both result in a png_error call prior to release, while in a
1720  * released version the 'warning' is just a warning.  However if the application
1721  * explicitly disables benign errors (explicitly permitting the code to lose
1722  * information) they both turn into warnings.
1723  *
1724  * If benign errors aren't supported they end up as the corresponding base call
1725  * (png_warning or png_error.)
1726  */
1727 PNG_INTERNAL_FUNCTION(void,png_app_warning,(png_const_structrp png_ptr,
1728    png_const_charp message),PNG_EMPTY);
1729    /* The application provided invalid parameters to an API function or called
1730     * an API function at the wrong time, libpng can completely recover.
1731     */
1732 
1733 PNG_INTERNAL_FUNCTION(void,png_app_error,(png_const_structrp png_ptr,
1734    png_const_charp message),PNG_EMPTY);
1735    /* As above but libpng will ignore the call, or attempt some other partial
1736     * recovery from the error.
1737     */
1738 #else
1739 #  define png_app_warning(pp,s) png_warning(pp,s)
1740 #  define png_app_error(pp,s) png_error(pp,s)
1741 #endif
1742 
1743 PNG_INTERNAL_FUNCTION(void,png_chunk_report,(png_const_structrp png_ptr,
1744    png_const_charp message, int error),PNG_EMPTY);
1745    /* Report a recoverable issue in chunk data.  On read this is used to report
1746     * a problem found while reading a particular chunk and the
1747     * png_chunk_benign_error or png_chunk_warning function is used as
1748     * appropriate.  On write this is used to report an error that comes from
1749     * data set via an application call to a png_set_ API and png_app_error or
1750     * png_app_warning is used as appropriate.
1751     *
1752     * The 'error' parameter must have one of the following values:
1753     */
1754 #define PNG_CHUNK_WARNING     0 /* never an error */
1755 #define PNG_CHUNK_WRITE_ERROR 1 /* an error only on write */
1756 #define PNG_CHUNK_ERROR       2 /* always an error */
1757 
1758 /* ASCII to FP interfaces, currently only implemented if sCAL
1759  * support is required.
1760  */
1761 #if defined(PNG_sCAL_SUPPORTED)
1762 /* MAX_DIGITS is actually the maximum number of characters in an sCAL
1763  * width or height, derived from the precision (number of significant
1764  * digits - a build time settable option) and assumptions about the
1765  * maximum ridiculous exponent.
1766  */
1767 #define PNG_sCAL_MAX_DIGITS (PNG_sCAL_PRECISION+1/*.*/+1/*E*/+10/*exponent*/)
1768 
1769 #ifdef PNG_FLOATING_POINT_SUPPORTED
1770 PNG_INTERNAL_FUNCTION(void,png_ascii_from_fp,(png_const_structrp png_ptr,
1771    png_charp ascii, png_size_t size, double fp, unsigned int precision),
1772    PNG_EMPTY);
1773 #endif /* FLOATING_POINT */
1774 
1775 #ifdef PNG_FIXED_POINT_SUPPORTED
1776 PNG_INTERNAL_FUNCTION(void,png_ascii_from_fixed,(png_const_structrp png_ptr,
1777    png_charp ascii, png_size_t size, png_fixed_point fp),PNG_EMPTY);
1778 #endif /* FIXED_POINT */
1779 #endif /* sCAL */
1780 
1781 #if defined(PNG_sCAL_SUPPORTED) || defined(PNG_pCAL_SUPPORTED)
1782 /* An internal API to validate the format of a floating point number.
1783  * The result is the index of the next character.  If the number is
1784  * not valid it will be the index of a character in the supposed number.
1785  *
1786  * The format of a number is defined in the PNG extensions specification
1787  * and this API is strictly conformant to that spec, not anyone elses!
1788  *
1789  * The format as a regular expression is:
1790  *
1791  * [+-]?[0-9]+.?([Ee][+-]?[0-9]+)?
1792  *
1793  * or:
1794  *
1795  * [+-]?.[0-9]+(.[0-9]+)?([Ee][+-]?[0-9]+)?
1796  *
1797  * The complexity is that either integer or fraction must be present and the
1798  * fraction is permitted to have no digits only if the integer is present.
1799  *
1800  * NOTE: The dangling E problem.
1801  *   There is a PNG valid floating point number in the following:
1802  *
1803  *       PNG floating point numbers are not greedy.
1804  *
1805  *   Working this out requires *TWO* character lookahead (because of the
1806  *   sign), the parser does not do this - it will fail at the 'r' - this
1807  *   doesn't matter for PNG sCAL chunk values, but it requires more care
1808  *   if the value were ever to be embedded in something more complex.  Use
1809  *   ANSI-C strtod if you need the lookahead.
1810  */
1811 /* State table for the parser. */
1812 #define PNG_FP_INTEGER    0  /* before or in integer */
1813 #define PNG_FP_FRACTION   1  /* before or in fraction */
1814 #define PNG_FP_EXPONENT   2  /* before or in exponent */
1815 #define PNG_FP_STATE      3  /* mask for the above */
1816 #define PNG_FP_SAW_SIGN   4  /* Saw +/- in current state */
1817 #define PNG_FP_SAW_DIGIT  8  /* Saw a digit in current state */
1818 #define PNG_FP_SAW_DOT   16  /* Saw a dot in current state */
1819 #define PNG_FP_SAW_E     32  /* Saw an E (or e) in current state */
1820 #define PNG_FP_SAW_ANY   60  /* Saw any of the above 4 */
1821 
1822 /* These three values don't affect the parser.  They are set but not used.
1823  */
1824 #define PNG_FP_WAS_VALID 64  /* Preceding substring is a valid fp number */
1825 #define PNG_FP_NEGATIVE 128  /* A negative number, including "-0" */
1826 #define PNG_FP_NONZERO  256  /* A non-zero value */
1827 #define PNG_FP_STICKY   448  /* The above three flags */
1828 
1829 /* This is available for the caller to store in 'state' if required.  Do not
1830  * call the parser after setting it (the parser sometimes clears it.)
1831  */
1832 #define PNG_FP_INVALID  512  /* Available for callers as a distinct value */
1833 
1834 /* Result codes for the parser (boolean - true meants ok, false means
1835  * not ok yet.)
1836  */
1837 #define PNG_FP_MAYBE      0  /* The number may be valid in the future */
1838 #define PNG_FP_OK         1  /* The number is valid */
1839 
1840 /* Tests on the sticky non-zero and negative flags.  To pass these checks
1841  * the state must also indicate that the whole number is valid - this is
1842  * achieved by testing PNG_FP_SAW_DIGIT (see the implementation for why this
1843  * is equivalent to PNG_FP_OK above.)
1844  */
1845 #define PNG_FP_NZ_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NEGATIVE | PNG_FP_NONZERO)
1846    /* NZ_MASK: the string is valid and a non-zero negative value */
1847 #define PNG_FP_Z_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NONZERO)
1848    /* Z MASK: the string is valid and a non-zero value. */
1849    /* PNG_FP_SAW_DIGIT: the string is valid. */
1850 #define PNG_FP_IS_ZERO(state) (((state) & PNG_FP_Z_MASK) == PNG_FP_SAW_DIGIT)
1851 #define PNG_FP_IS_POSITIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_Z_MASK)
1852 #define PNG_FP_IS_NEGATIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_NZ_MASK)
1853 
1854 /* The actual parser.  This can be called repeatedly. It updates
1855  * the index into the string and the state variable (which must
1856  * be initialized to 0).  It returns a result code, as above.  There
1857  * is no point calling the parser any more if it fails to advance to
1858  * the end of the string - it is stuck on an invalid character (or
1859  * terminated by '\0').
1860  *
1861  * Note that the pointer will consume an E or even an E+ and then leave
1862  * a 'maybe' state even though a preceding integer.fraction is valid.
1863  * The PNG_FP_WAS_VALID flag indicates that a preceding substring was
1864  * a valid number.  It's possible to recover from this by calling
1865  * the parser again (from the start, with state 0) but with a string
1866  * that omits the last character (i.e. set the size to the index of
1867  * the problem character.)  This has not been tested within libpng.
1868  */
1869 PNG_INTERNAL_FUNCTION(int,png_check_fp_number,(png_const_charp string,
1870    png_size_t size, int *statep, png_size_tp whereami),PNG_EMPTY);
1871 
1872 /* This is the same but it checks a complete string and returns true
1873  * only if it just contains a floating point number.  As of 1.5.4 this
1874  * function also returns the state at the end of parsing the number if
1875  * it was valid (otherwise it returns 0.)  This can be used for testing
1876  * for negative or zero values using the sticky flag.
1877  */
1878 PNG_INTERNAL_FUNCTION(int,png_check_fp_string,(png_const_charp string,
1879    png_size_t size),PNG_EMPTY);
1880 #endif /* pCAL || sCAL */
1881 
1882 #if defined(PNG_GAMMA_SUPPORTED) ||\
1883     defined(PNG_INCH_CONVERSIONS_SUPPORTED) || defined(PNG_READ_pHYs_SUPPORTED)
1884 /* Added at libpng version 1.5.0 */
1885 /* This is a utility to provide a*times/div (rounded) and indicate
1886  * if there is an overflow.  The result is a boolean - false (0)
1887  * for overflow, true (1) if no overflow, in which case *res
1888  * holds the result.
1889  */
1890 PNG_INTERNAL_FUNCTION(int,png_muldiv,(png_fixed_point_p res, png_fixed_point a,
1891    png_int_32 multiplied_by, png_int_32 divided_by),PNG_EMPTY);
1892 #endif
1893 
1894 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_INCH_CONVERSIONS_SUPPORTED)
1895 /* Same deal, but issue a warning on overflow and return 0. */
1896 PNG_INTERNAL_FUNCTION(png_fixed_point,png_muldiv_warn,
1897    (png_const_structrp png_ptr, png_fixed_point a, png_int_32 multiplied_by,
1898    png_int_32 divided_by),PNG_EMPTY);
1899 #endif
1900 
1901 #ifdef PNG_GAMMA_SUPPORTED
1902 /* Calculate a reciprocal - used for gamma values.  This returns
1903  * 0 if the argument is 0 in order to maintain an undefined value;
1904  * there are no warnings.
1905  */
1906 PNG_INTERNAL_FUNCTION(png_fixed_point,png_reciprocal,(png_fixed_point a),
1907    PNG_EMPTY);
1908 
1909 #ifdef PNG_READ_GAMMA_SUPPORTED
1910 /* The same but gives a reciprocal of the product of two fixed point
1911  * values.  Accuracy is suitable for gamma calculations but this is
1912  * not exact - use png_muldiv for that.  Only required at present on read.
1913  */
1914 PNG_INTERNAL_FUNCTION(png_fixed_point,png_reciprocal2,(png_fixed_point a,
1915    png_fixed_point b),PNG_EMPTY);
1916 #endif
1917 
1918 /* Return true if the gamma value is significantly different from 1.0 */
1919 PNG_INTERNAL_FUNCTION(int,png_gamma_significant,(png_fixed_point gamma_value),
1920    PNG_EMPTY);
1921 #endif
1922 
1923 #ifdef PNG_READ_GAMMA_SUPPORTED
1924 /* Internal fixed point gamma correction.  These APIs are called as
1925  * required to convert single values - they don't need to be fast,
1926  * they are not used when processing image pixel values.
1927  *
1928  * While the input is an 'unsigned' value it must actually be the
1929  * correct bit value - 0..255 or 0..65535 as required.
1930  */
1931 PNG_INTERNAL_FUNCTION(png_uint_16,png_gamma_correct,(png_structrp png_ptr,
1932    unsigned int value, png_fixed_point gamma_value),PNG_EMPTY);
1933 PNG_INTERNAL_FUNCTION(png_uint_16,png_gamma_16bit_correct,(unsigned int value,
1934    png_fixed_point gamma_value),PNG_EMPTY);
1935 PNG_INTERNAL_FUNCTION(png_byte,png_gamma_8bit_correct,(unsigned int value,
1936    png_fixed_point gamma_value),PNG_EMPTY);
1937 PNG_INTERNAL_FUNCTION(void,png_destroy_gamma_table,(png_structrp png_ptr),
1938    PNG_EMPTY);
1939 PNG_INTERNAL_FUNCTION(void,png_build_gamma_table,(png_structrp png_ptr,
1940    int bit_depth),PNG_EMPTY);
1941 #endif
1942 
1943 /* SIMPLIFIED READ/WRITE SUPPORT */
1944 #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
1945    defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
1946 /* The internal structure that png_image::opaque points to. */
1947 typedef struct png_control
1948 {
1949    png_structp png_ptr;
1950    png_infop   info_ptr;
1951    png_voidp   error_buf;           /* Always a jmp_buf at present. */
1952 
1953    png_const_bytep memory;          /* Memory buffer. */
1954    png_size_t      size;            /* Size of the memory buffer. */
1955 
1956    unsigned int for_write       :1; /* Otherwise it is a read structure */
1957    unsigned int owned_file      :1; /* We own the file in io_ptr */
1958 } png_control;
1959 
1960 /* Return the pointer to the jmp_buf from a png_control: necessary because C
1961  * does not reveal the type of the elements of jmp_buf.
1962  */
1963 #ifdef __cplusplus
1964 #  define png_control_jmp_buf(pc) (((jmp_buf*)((pc)->error_buf))[0])
1965 #else
1966 #  define png_control_jmp_buf(pc) ((pc)->error_buf)
1967 #endif
1968 
1969 /* Utility to safely execute a piece of libpng code catching and logging any
1970  * errors that might occur.  Returns true on success, false on failure (either
1971  * of the function or as a result of a png_error.)
1972  */
1973 PNG_INTERNAL_CALLBACK(void,png_safe_error,(png_structp png_ptr,
1974    png_const_charp error_message),PNG_NORETURN);
1975 
1976 #ifdef PNG_WARNINGS_SUPPORTED
1977 PNG_INTERNAL_CALLBACK(void,png_safe_warning,(png_structp png_ptr,
1978    png_const_charp warning_message),PNG_EMPTY);
1979 #else
1980 #  define png_safe_warning 0/*dummy argument*/
1981 #endif
1982 
1983 PNG_INTERNAL_FUNCTION(int,png_safe_execute,(png_imagep image,
1984    int (*function)(png_voidp), png_voidp arg),PNG_EMPTY);
1985 
1986 /* Utility to log an error; this also cleans up the png_image; the function
1987  * always returns 0 (false).
1988  */
1989 PNG_INTERNAL_FUNCTION(int,png_image_error,(png_imagep image,
1990    png_const_charp error_message),PNG_EMPTY);
1991 
1992 #ifndef PNG_SIMPLIFIED_READ_SUPPORTED
1993 /* png_image_free is used by the write code but not exported */
1994 PNG_INTERNAL_FUNCTION(void, png_image_free, (png_imagep image), PNG_EMPTY);
1995 #endif /* !SIMPLIFIED_READ */
1996 
1997 #endif /* SIMPLIFIED READ/WRITE */
1998 
1999 /* These are initialization functions for hardware specific PNG filter
2000  * optimizations; list these here then select the appropriate one at compile
2001  * time using the macro PNG_FILTER_OPTIMIZATIONS.  If the macro is not defined
2002  * the generic code is used.
2003  */
2004 #ifdef PNG_FILTER_OPTIMIZATIONS
2005 PNG_INTERNAL_FUNCTION(void, PNG_FILTER_OPTIMIZATIONS, (png_structp png_ptr,
2006    unsigned int bpp), PNG_EMPTY);
2007    /* Just declare the optimization that will be used */
2008 #else
2009    /* List *all* the possible optimizations here - this branch is required if
2010     * the builder of libpng passes the definition of PNG_FILTER_OPTIMIZATIONS in
2011     * CFLAGS in place of CPPFLAGS *and* uses symbol prefixing.
2012     */
2013 #  if PNG_ARM_NEON_OPT > 0
2014 PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_neon,
2015    (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
2016 #endif
2017 
2018 #if PNG_MIPS_MSA_OPT > 0
2019 PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_msa,
2020    (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
2021 #endif
2022 #endif
2023 
2024 PNG_INTERNAL_FUNCTION(png_uint_32, png_check_keyword, (png_structrp png_ptr,
2025    png_const_charp key, png_bytep new_key), PNG_EMPTY);
2026 
2027 /* Maintainer: Put new private prototypes here ^ */
2028 
2029 #include "pngdebug.h"
2030 
2031 #ifdef __cplusplus
2032 }
2033 #endif
2034 
2035 #endif /* PNG_VERSION_INFO_ONLY */
2036 #endif /* PNGPRIV_H */