1 
2 /* pngpriv.h - private declarations for use inside libpng
3  *
4  * Last changed in libpng 1.6.21 [(PENDING RELEASE)]
5  * Copyright (c) 1998-2002,2004,2006-2015 Glenn Randers-Pehrson
6  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
7  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
8  *
9  * This code is released under the libpng license.
10  * For conditions of distribution and use, see the disclaimer
11  * and license in png.h
12  */
13 
14 /* The symbols declared in this file (including the functions declared
15  * as extern) are PRIVATE.  They are not part of the libpng public
16  * interface, and are not recommended for use by regular applications.
17  * Some of them may become public in the future; others may stay private,
18  * change in an incompatible way, or even disappear.
19  * Although the libpng users are not forbidden to include this header,
20  * they should be well aware of the issues that may arise from doing so.
21  */
22 
23 #ifndef PNGPRIV_H
24 #define PNGPRIV_H
25 
26 /* Feature Test Macros.  The following are defined here to ensure that correctly
27  * implemented libraries reveal the APIs libpng needs to build and hide those
28  * that are not needed and potentially damaging to the compilation.
29  *
30  * Feature Test Macros must be defined before any system header is included (see
31  * POSIX 1003.1 2.8.2 "POSIX Symbols."
32  *
33  * These macros only have an effect if the operating system supports either
34  * POSIX 1003.1 or C99, or both.  On other operating systems (particularly
35  * Windows/Visual Studio) there is no effect; the OS specific tests below are
36  * still required (as of 2011-05-02.)
37  */
38 #define _POSIX_SOURCE 1 /* Just the POSIX 1003.1 and C89 APIs */
39 
40 #ifndef PNG_VERSION_INFO_ONLY
41 /* Standard library headers not required by png.h: */
42 #  include <stdlib.h>
43 #  include <string.h>
44 #endif
45 
46 #define PNGLIB_BUILD /*libpng is being built, not used*/
47 
48 /* If HAVE_CONFIG_H is defined during the build then the build system must
49  * provide an appropriate "config.h" file on the include path.  The header file
50  * must provide definitions as required below (search for "HAVE_CONFIG_H");
51  * see configure.ac for more details of the requirements.  The macro
52  * "PNG_NO_CONFIG_H" is provided for maintainers to test for dependencies on
53  * 'configure'; define this macro to prevent the configure build including the
54  * configure generated config.h.  Libpng is expected to compile without *any*
55  * special build system support on a reasonably ANSI-C compliant system.
56  */
57 #if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
58 #  include <config.h>
59 
60    /* Pick up the definition of 'restrict' from config.h if it was read: */
61 #  define PNG_RESTRICT restrict
62 #endif
63 
64 /* To support symbol prefixing it is necessary to know *before* including png.h
65  * whether the fixed point (and maybe other) APIs are exported, because if they
66  * are not internal definitions may be required.  This is handled below just
67  * before png.h is included, but load the configuration now if it is available.
68  */
69 #ifndef PNGLCONF_H
70 #  include "pnglibconf.h"
71 #endif
72 
73 /* Local renames may change non-exported API functions from png.h */
74 #if defined(PNG_PREFIX) && !defined(PNGPREFIX_H)
75 #  include "pngprefix.h"
76 #endif
77 
78 #ifdef PNG_USER_CONFIG
79 #  include "pngusr.h"
80    /* These should have been defined in pngusr.h */
81 #  ifndef PNG_USER_PRIVATEBUILD
82 #    define PNG_USER_PRIVATEBUILD "Custom libpng build"
83 #  endif
84 #  ifndef PNG_USER_DLLFNAME_POSTFIX
85 #    define PNG_USER_DLLFNAME_POSTFIX "Cb"
86 #  endif
87 #endif
88 
89 /* Compile time options.
90  * =====================
91  * In a multi-arch build the compiler may compile the code several times for the
92  * same object module, producing different binaries for different architectures.
93  * When this happens configure-time setting of the target host options cannot be
94  * done and this interferes with the handling of the ARM NEON optimizations, and
95  * possibly other similar optimizations.  Put additional tests here; in general
96  * this is needed when the same option can be changed at both compile time and
97  * run time depending on the target OS (i.e. iOS vs Android.)
98  *
99  * NOTE: symbol prefixing does not pass $(CFLAGS) to the preprocessor, because
100  * this is not possible with certain compilers (Oracle SUN OS CC), as a result
101  * it is necessary to ensure that all extern functions that *might* be used
102  * regardless of $(CFLAGS) get declared in this file.  The test on __ARM_NEON__
103  * below is one example of this behavior because it is controlled by the
104  * presence or not of -mfpu=neon on the GCC command line, it is possible to do
105  * this in $(CC), e.g. "CC=gcc -mfpu=neon", but people who build libpng rarely
106  * do this.
107  */
108 #ifndef PNG_ARM_NEON_OPT
109    /* ARM NEON optimizations are being controlled by the compiler settings,
110     * typically the target FPU.  If the FPU has been set to NEON (-mfpu=neon
111     * with GCC) then the compiler will define __ARM_NEON__ and we can rely
112     * unconditionally on NEON instructions not crashing, otherwise we must
113     * disable use of NEON instructions.
114     *
115     * NOTE: at present these optimizations depend on 'ALIGNED_MEMORY', so they
116     * can only be turned on automatically if that is supported too.  If
117     * PNG_ARM_NEON_OPT is set in CPPFLAGS (to >0) then arm/arm_init.c will fail
118     * to compile with an appropriate #error if ALIGNED_MEMORY has been turned
119     * off.
120     *
121     * Note that gcc-4.9 defines __ARM_NEON instead of the deprecated
122     * __ARM_NEON__, so we check both variants.
123     *
124     * To disable ARM_NEON optimizations entirely, and skip compiling the
125     * associated assembler code, pass --enable-arm-neon=no to configure
126     * or put -DPNG_ARM_NEON_OPT=0 in CPPFLAGS.
127     */
128 #  if (defined(__ARM_NEON__) || defined(__ARM_NEON)) && \
129    defined(PNG_ALIGNED_MEMORY_SUPPORTED)
130 #     define PNG_ARM_NEON_OPT 2
131 #  else
132 #     define PNG_ARM_NEON_OPT 0
133 #  endif
134 #endif
135 
136 #if PNG_ARM_NEON_OPT > 0
137    /* NEON optimizations are to be at least considered by libpng, so enable the
138     * callbacks to do this.
139     */
140 #  define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_neon
141 
142    /* By default the 'intrinsics' code in arm/filter_neon_intrinsics.c is used
143     * if possible - if __ARM_NEON__ is set and the compiler version is not known
144     * to be broken.  This is controlled by PNG_ARM_NEON_IMPLEMENTATION which can
145     * be:
146     *
147     *    1  The intrinsics code (the default with __ARM_NEON__)
148     *    2  The hand coded assembler (the default without __ARM_NEON__)
149     *
150     * It is possible to set PNG_ARM_NEON_IMPLEMENTATION in CPPFLAGS, however
151     * this is *NOT* supported and may cease to work even after a minor revision
152     * to libpng.  It *is* valid to do this for testing purposes, e.g. speed
153     * testing or a new compiler, but the results should be communicated to the
154     * libpng implementation list for incorporation in the next minor release.
155     */
156 #  ifndef PNG_ARM_NEON_IMPLEMENTATION
157 #     if defined(__ARM_NEON__) || defined(__ARM_NEON)
158 #        if defined(__clang__)
159             /* At present it is unknown by the libpng developers which versions
160              * of clang support the intrinsics, however some or perhaps all
161              * versions do not work with the assembler so this may be
162              * irrelevant, so just use the default (do nothing here.)
163              */
164 #        elif defined(__GNUC__)
165             /* GCC 4.5.4 NEON support is known to be broken.  4.6.3 is known to
166              * work, so if this *is* GCC, or G++, look for a version >4.5
167              */
168 #           if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 6)
169 #              define PNG_ARM_NEON_IMPLEMENTATION 2
170 #           endif /* no GNUC support */
171 #        endif /* __GNUC__ */
172 #     else /* !defined __ARM_NEON__ */
173          /* The 'intrinsics' code simply won't compile without this -mfpu=neon:
174           */
175 #        define PNG_ARM_NEON_IMPLEMENTATION 2
176 #     endif /* __ARM_NEON__ */
177 #  endif /* !PNG_ARM_NEON_IMPLEMENTATION */
178 
179 #  ifndef PNG_ARM_NEON_IMPLEMENTATION
180       /* Use the intrinsics code by default. */
181 #     define PNG_ARM_NEON_IMPLEMENTATION 1
182 #  endif
183 #endif /* PNG_ARM_NEON_OPT > 0 */
184 
185 #ifndef PNG_INTEL_SSE_OPT
186 #   ifdef PNG_INTEL_SSE
187       /* Only check for SSE if the build configuration has been modified to
188        * enable SSE optimizations.  This means that these optimizations will
189        * be off by default.  See contrib/intel for more details.
190        */
191 #     if defined(__SSE4_1__) || defined(__AVX__) || defined(__SSSE3__) || \
192        defined(__SSE2__) || defined(_M_X64) || defined(_M_AMD64) || \
193        (defined(_M_IX86_FP) && _M_IX86_FP >= 2)
194 #         define PNG_INTEL_SSE_OPT 1
195 #      endif
196 #   endif
197 #endif
198 
199 #if PNG_INTEL_SSE_OPT > 0
200 #   ifndef PNG_INTEL_SSE_IMPLEMENTATION
201 #      if defined(__SSE4_1__) || defined(__AVX__)
202           /* We are not actually using AVX, but checking for AVX is the best
203              way we can detect SSE4.1 and SSSE3 on MSVC.
204           */
205 #         define PNG_INTEL_SSE_IMPLEMENTATION 3
206 #      elif defined(__SSSE3__)
207 #         define PNG_INTEL_SSE_IMPLEMENTATION 2
208 #      elif defined(__SSE2__) || defined(_M_X64) || defined(_M_AMD64) || \
209        (defined(_M_IX86_FP) && _M_IX86_FP >= 2)
210 #         define PNG_INTEL_SSE_IMPLEMENTATION 1
211 #      else
212 #         define PNG_INTEL_SSE_IMPLEMENTATION 0
213 #      endif
214 #   endif
215 
216 #   if PNG_INTEL_SSE_IMPLEMENTATION > 0
217 #      define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_sse2
218 #   endif
219 #endif
220 
221 /* Is this a build of a DLL where compilation of the object modules requires
222  * different preprocessor settings to those required for a simple library?  If
223  * so PNG_BUILD_DLL must be set.
224  *
225  * If libpng is used inside a DLL but that DLL does not export the libpng APIs
226  * PNG_BUILD_DLL must not be set.  To avoid the code below kicking in build a
227  * static library of libpng then link the DLL against that.
228  */
229 #ifndef PNG_BUILD_DLL
230 #  ifdef DLL_EXPORT
231       /* This is set by libtool when files are compiled for a DLL; libtool
232        * always compiles twice, even on systems where it isn't necessary.  Set
233        * PNG_BUILD_DLL in case it is necessary:
234        */
235 #     define PNG_BUILD_DLL
236 #  else
237 #     ifdef _WINDLL
238          /* This is set by the Microsoft Visual Studio IDE in projects that
239           * build a DLL.  It can't easily be removed from those projects (it
240           * isn't visible in the Visual Studio UI) so it is a fairly reliable
241           * indication that PNG_IMPEXP needs to be set to the DLL export
242           * attributes.
243           */
244 #        define PNG_BUILD_DLL
245 #     else
246 #        ifdef __DLL__
247             /* This is set by the Borland C system when compiling for a DLL
248              * (as above.)
249              */
250 #           define PNG_BUILD_DLL
251 #        else
252             /* Add additional compiler cases here. */
253 #        endif
254 #     endif
255 #  endif
256 #endif /* Setting PNG_BUILD_DLL if required */
257 
258 /* See pngconf.h for more details: the builder of the library may set this on
259  * the command line to the right thing for the specific compilation system or it
260  * may be automagically set above (at present we know of no system where it does
261  * need to be set on the command line.)
262  *
263  * PNG_IMPEXP must be set here when building the library to prevent pngconf.h
264  * setting it to the "import" setting for a DLL build.
265  */
266 #ifndef PNG_IMPEXP
267 #  ifdef PNG_BUILD_DLL
268 #     define PNG_IMPEXP PNG_DLL_EXPORT
269 #  else
270       /* Not building a DLL, or the DLL doesn't require specific export
271        * definitions.
272        */
273 #     define PNG_IMPEXP
274 #  endif
275 #endif
276 
277 /* No warnings for private or deprecated functions in the build: */
278 #ifndef PNG_DEPRECATED
279 #  define PNG_DEPRECATED
280 #endif
281 #ifndef PNG_PRIVATE
282 #  define PNG_PRIVATE
283 #endif
284 
285 /* Symbol preprocessing support.
286  *
287  * To enable listing global, but internal, symbols the following macros should
288  * always be used to declare an extern data or function object in this file.
289  */
290 #ifndef PNG_INTERNAL_DATA
291 #  define PNG_INTERNAL_DATA(type, name, array) PNG_LINKAGE_DATA type name array
292 #endif
293 
294 #ifndef PNG_INTERNAL_FUNCTION
295 #  define PNG_INTERNAL_FUNCTION(type, name, args, attributes)\
296       PNG_LINKAGE_FUNCTION PNG_FUNCTION(type, name, args, PNG_EMPTY attributes)
297 #endif
298 
299 #ifndef PNG_INTERNAL_CALLBACK
300 #  define PNG_INTERNAL_CALLBACK(type, name, args, attributes)\
301       PNG_LINKAGE_CALLBACK PNG_FUNCTION(type, (PNGCBAPI name), args,\
302          PNG_EMPTY attributes)
303 #endif
304 
305 /* If floating or fixed point APIs are disabled they may still be compiled
306  * internally.  To handle this make sure they are declared as the appropriate
307  * internal extern function (otherwise the symbol prefixing stuff won't work and
308  * the functions will be used without definitions.)
309  *
310  * NOTE: although all the API functions are declared here they are not all
311  * actually built!  Because the declarations are still made it is necessary to
312  * fake out types that they depend on.
313  */
314 #ifndef PNG_FP_EXPORT
315 #  ifndef PNG_FLOATING_POINT_SUPPORTED
316 #     define PNG_FP_EXPORT(ordinal, type, name, args)\
317          PNG_INTERNAL_FUNCTION(type, name, args, PNG_EMPTY);
318 #     ifndef PNG_VERSION_INFO_ONLY
319          typedef struct png_incomplete png_double;
320          typedef png_double*           png_doublep;
321          typedef const png_double*     png_const_doublep;
322          typedef png_double**          png_doublepp;
323 #     endif
324 #  endif
325 #endif
326 #ifndef PNG_FIXED_EXPORT
327 #  ifndef PNG_FIXED_POINT_SUPPORTED
328 #     define PNG_FIXED_EXPORT(ordinal, type, name, args)\
329          PNG_INTERNAL_FUNCTION(type, name, args, PNG_EMPTY);
330 #  endif
331 #endif
332 
333 #include "png.h"
334 
335 /* pngconf.h does not set PNG_DLL_EXPORT unless it is required, so: */
336 #ifndef PNG_DLL_EXPORT
337 #  define PNG_DLL_EXPORT
338 #endif
339 
340 /* This is a global switch to set the compilation for an installed system
341  * (a release build).  It can be set for testing debug builds to ensure that
342  * they will compile when the build type is switched to RC or STABLE, the
343  * default is just to use PNG_LIBPNG_BUILD_BASE_TYPE.  Set this in CPPFLAGS
344  * with either:
345  *
346  *   -DPNG_RELEASE_BUILD Turns on the release compile path
347  *   -DPNG_RELEASE_BUILD=0 Turns it off
348  * or in your pngusr.h with
349  *   #define PNG_RELEASE_BUILD=1 Turns on the release compile path
350  *   #define PNG_RELEASE_BUILD=0 Turns it off
351  */
352 #ifndef PNG_RELEASE_BUILD
353 #  define PNG_RELEASE_BUILD (PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC)
354 #endif
355 
356 /* SECURITY and SAFETY:
357  *
358  * libpng is built with support for internal limits on image dimensions and
359  * memory usage.  These are documented in scripts/pnglibconf.dfa of the
360  * source and recorded in the machine generated header file pnglibconf.h.
361  */
362 
363 /* If you are running on a machine where you cannot allocate more
364  * than 64K of memory at once, uncomment this.  While libpng will not
365  * normally need that much memory in a chunk (unless you load up a very
366  * large file), zlib needs to know how big of a chunk it can use, and
367  * libpng thus makes sure to check any memory allocation to verify it
368  * will fit into memory.
369  *
370  * zlib provides 'MAXSEG_64K' which, if defined, indicates the
371  * same limit and pngconf.h (already included) sets the limit
372  * if certain operating systems are detected.
373  */
374 #if defined(MAXSEG_64K) && !defined(PNG_MAX_MALLOC_64K)
375 #  define PNG_MAX_MALLOC_64K
376 #endif
377 
378 #ifndef PNG_UNUSED
379 /* Unused formal parameter warnings are silenced using the following macro
380  * which is expected to have no bad effects on performance (optimizing
381  * compilers will probably remove it entirely).  Note that if you replace
382  * it with something other than whitespace, you must include the terminating
383  * semicolon.
384  */
385 #  define PNG_UNUSED(param) (void)param;
386 #endif
387 
388 /* Just a little check that someone hasn't tried to define something
389  * contradictory.
390  */
391 #if (PNG_ZBUF_SIZE > 65536L) && defined(PNG_MAX_MALLOC_64K)
392 #  undef PNG_ZBUF_SIZE
393 #  define PNG_ZBUF_SIZE 65536L
394 #endif
395 
396 /* If warnings or errors are turned off the code is disabled or redirected here.
397  * From 1.5.4 functions have been added to allow very limited formatting of
398  * error and warning messages - this code will also be disabled here.
399  */
400 #ifdef PNG_WARNINGS_SUPPORTED
401 #  define PNG_WARNING_PARAMETERS(p) png_warning_parameters p;
402 #else
403 #  define png_warning_parameter(p,number,string) ((void)0)
404 #  define png_warning_parameter_unsigned(p,number,format,value) ((void)0)
405 #  define png_warning_parameter_signed(p,number,format,value) ((void)0)
406 #  define png_formatted_warning(pp,p,message) ((void)(pp))
407 #  define PNG_WARNING_PARAMETERS(p)
408 #endif
409 #ifndef PNG_ERROR_TEXT_SUPPORTED
410 #  define png_fixed_error(s1,s2) png_err(s1)
411 #endif
412 
413 /* C allows up-casts from (void*) to any pointer and (const void*) to any
414  * pointer to a const object.  C++ regards this as a type error and requires an
415  * explicit, static, cast and provides the static_cast<> rune to ensure that
416  * const is not cast away.
417  */
418 #ifdef __cplusplus
419 #  define png_voidcast(type, value) static_cast<type>(value)
420 #  define png_constcast(type, value) const_cast<type>(value)
421 #  define png_aligncast(type, value) \
422    static_cast<type>(static_cast<void*>(value))
423 #  define png_aligncastconst(type, value) \
424    static_cast<type>(static_cast<const void*>(value))
425 #else
426 #  define png_voidcast(type, value) (value)
427 #  define png_constcast(type, value) ((type)(value))
428 #  define png_aligncast(type, value) ((void*)(value))
429 #  define png_aligncastconst(type, value) ((const void*)(value))
430 #endif /* __cplusplus */
431 
432 /* Some fixed point APIs are still required even if not exported because
433  * they get used by the corresponding floating point APIs.  This magic
434  * deals with this:
435  */
436 #ifdef PNG_FIXED_POINT_SUPPORTED
437 #  define PNGFAPI PNGAPI
438 #else
439 #  define PNGFAPI /* PRIVATE */
440 #endif
441 
442 #ifndef PNG_VERSION_INFO_ONLY
443 /* Other defines specific to compilers can go here.  Try to keep
444  * them inside an appropriate ifdef/endif pair for portability.
445  */
446 #if defined(PNG_FLOATING_POINT_SUPPORTED) ||\
447     defined(PNG_FLOATING_ARITHMETIC_SUPPORTED)
448    /* png.c requires the following ANSI-C constants if the conversion of
449     * floating point to ASCII is implemented therein:
450     *
451     *  DBL_DIG  Maximum number of decimal digits (can be set to any constant)
452     *  DBL_MIN  Smallest normalized fp number (can be set to an arbitrary value)
453     *  DBL_MAX  Maximum floating point number (can be set to an arbitrary value)
454     */
455 #  include <float.h>
456 
457 #  if (defined(__MWERKS__) && defined(macintosh)) || defined(applec) || \
458     defined(THINK_C) || defined(__SC__) || defined(TARGET_OS_MAC)
459      /* We need to check that <math.h> hasn't already been included earlier
460       * as it seems it doesn't agree with <fp.h>, yet we should really use
461       * <fp.h> if possible.
462       */
463 #    if !defined(__MATH_H__) && !defined(__MATH_H) && !defined(__cmath__)
464 #      include <fp.h>
465 #    endif
466 #  else
467 #    include <math.h>
468 #  endif
469 #  if defined(_AMIGA) && defined(__SASC) && defined(_M68881)
470      /* Amiga SAS/C: We must include builtin FPU functions when compiling using
471       * MATH=68881
472       */
473 #    include <m68881.h>
474 #  endif
475 #endif
476 
477 /* This provides the non-ANSI (far) memory allocation routines. */
478 #if defined(__TURBOC__) && defined(__MSDOS__)
479 #  include <mem.h>
480 #  include <alloc.h>
481 #endif
482 
483 #if defined(WIN32) || defined(_Windows) || defined(_WINDOWS) || \
484     defined(_WIN32) || defined(__WIN32__)
485 #  include <windows.h>  /* defines _WINDOWS_ macro */
486 #endif
487 #endif /* PNG_VERSION_INFO_ONLY */
488 
489 /* Moved here around 1.5.0beta36 from pngconf.h */
490 /* Users may want to use these so they are not private.  Any library
491  * functions that are passed far data must be model-independent.
492  */
493 
494 /* Memory model/platform independent fns */
495 #ifndef PNG_ABORT
496 #  ifdef _WINDOWS_
497 #    define PNG_ABORT() ExitProcess(0)
498 #  else
499 #    define PNG_ABORT() abort()
500 #  endif
501 #endif
502 
503 /* These macros may need to be architecture dependent. */
504 #define PNG_ALIGN_NONE   0 /* do not use data alignment */
505 #define PNG_ALIGN_ALWAYS 1 /* assume unaligned accesses are OK */
506 #ifdef offsetof
507 #  define PNG_ALIGN_OFFSET 2 /* use offsetof to determine alignment */
508 #else
509 #  define PNG_ALIGN_OFFSET -1 /* prevent the use of this */
510 #endif
511 #define PNG_ALIGN_SIZE   3 /* use sizeof to determine alignment */
512 
513 #ifndef PNG_ALIGN_TYPE
514    /* Default to using aligned access optimizations and requiring alignment to a
515     * multiple of the data type size.  Override in a compiler specific fashion
516     * if necessary by inserting tests here:
517     */
518 #  define PNG_ALIGN_TYPE PNG_ALIGN_SIZE
519 #endif
520 
521 #if PNG_ALIGN_TYPE == PNG_ALIGN_SIZE
522    /* This is used because in some compiler implementations non-aligned
523     * structure members are supported, so the offsetof approach below fails.
524     * Set PNG_ALIGN_SIZE=0 for compiler combinations where unaligned access
525     * is good for performance.  Do not do this unless you have tested the result
526     * and understand it.
527     */
528 #  define png_alignof(type) (sizeof (type))
529 #else
530 #  if PNG_ALIGN_TYPE == PNG_ALIGN_OFFSET
531 #     define png_alignof(type) offsetof(struct{char c; type t;}, t)
532 #  else
533 #     if PNG_ALIGN_TYPE == PNG_ALIGN_ALWAYS
534 #        define png_alignof(type) (1)
535 #     endif
536       /* Else leave png_alignof undefined to prevent use thereof */
537 #  endif
538 #endif
539 
540 /* This implicitly assumes alignment is always to a power of 2. */
541 #ifdef png_alignof
542 #  define png_isaligned(ptr, type)\
543    ((((const char*)ptr-(const char*)0) & (png_alignof(type)-1)) == 0)
544 #else
545 #  define png_isaligned(ptr, type) 0
546 #endif
547 
548 /* End of memory model/platform independent support */
549 /* End of 1.5.0beta36 move from pngconf.h */
550 
551 /* CONSTANTS and UTILITY MACROS
552  * These are used internally by libpng and not exposed in the API
553  */
554 
555 /* Various modes of operation.  Note that after an init, mode is set to
556  * zero automatically when the structure is created.  Three of these
557  * are defined in png.h because they need to be visible to applications
558  * that call png_set_unknown_chunk().
559  */
560 /* #define PNG_HAVE_IHDR            0x01 (defined in png.h) */
561 /* #define PNG_HAVE_PLTE            0x02 (defined in png.h) */
562 #define PNG_HAVE_IDAT               0x04
563 /* #define PNG_AFTER_IDAT           0x08 (defined in png.h) */
564 #define PNG_HAVE_IEND               0x10
565                    /*               0x20 (unused) */
566                    /*               0x40 (unused) */
567                    /*               0x80 (unused) */
568 #define PNG_HAVE_CHUNK_HEADER      0x100
569 #define PNG_WROTE_tIME             0x200
570 #define PNG_WROTE_INFO_BEFORE_PLTE 0x400
571 #define PNG_BACKGROUND_IS_GRAY     0x800
572 #define PNG_HAVE_PNG_SIGNATURE    0x1000
573 #define PNG_HAVE_CHUNK_AFTER_IDAT 0x2000 /* Have another chunk after IDAT */
574                    /*             0x4000 (unused) */
575 #define PNG_IS_READ_STRUCT        0x8000 /* Else is a write struct */
576 
577 /* Flags for the transformations the PNG library does on the image data */
578 #define PNG_BGR                 0x0001
579 #define PNG_INTERLACE           0x0002
580 #define PNG_PACK                0x0004
581 #define PNG_SHIFT               0x0008
582 #define PNG_SWAP_BYTES          0x0010
583 #define PNG_INVERT_MONO         0x0020
584 #define PNG_QUANTIZE            0x0040
585 #define PNG_COMPOSE             0x0080     /* Was PNG_BACKGROUND */
586 #define PNG_BACKGROUND_EXPAND   0x0100
587 #define PNG_EXPAND_16           0x0200     /* Added to libpng 1.5.2 */
588 #define PNG_16_TO_8             0x0400     /* Becomes 'chop' in 1.5.4 */
589 #define PNG_RGBA                0x0800
590 #define PNG_EXPAND              0x1000
591 #define PNG_GAMMA               0x2000
592 #define PNG_GRAY_TO_RGB         0x4000
593 #define PNG_FILLER              0x8000
594 #define PNG_PACKSWAP           0x10000
595 #define PNG_SWAP_ALPHA         0x20000
596 #define PNG_STRIP_ALPHA        0x40000
597 #define PNG_INVERT_ALPHA       0x80000
598 #define PNG_USER_TRANSFORM    0x100000
599 #define PNG_RGB_TO_GRAY_ERR   0x200000
600 #define PNG_RGB_TO_GRAY_WARN  0x400000
601 #define PNG_RGB_TO_GRAY       0x600000 /* two bits, RGB_TO_GRAY_ERR|WARN */
602 #define PNG_ENCODE_ALPHA      0x800000 /* Added to libpng-1.5.4 */
603 #define PNG_ADD_ALPHA        0x1000000 /* Added to libpng-1.2.7 */
604 #define PNG_EXPAND_tRNS      0x2000000 /* Added to libpng-1.2.9 */
605 #define PNG_SCALE_16_TO_8    0x4000000 /* Added to libpng-1.5.4 */
606                        /*    0x8000000 unused */
607                        /*   0x10000000 unused */
608                        /*   0x20000000 unused */
609                        /*   0x40000000 unused */
610 /* Flags for png_create_struct */
611 #define PNG_STRUCT_PNG   0x0001
612 #define PNG_STRUCT_INFO  0x0002
613 
614 /* Flags for the png_ptr->flags rather than declaring a byte for each one */
615 #define PNG_FLAG_ZLIB_CUSTOM_STRATEGY     0x0001
616 #define PNG_FLAG_ZSTREAM_INITIALIZED      0x0002 /* Added to libpng-1.6.0 */
617                                   /*      0x0004    unused */
618 #define PNG_FLAG_ZSTREAM_ENDED            0x0008 /* Added to libpng-1.6.0 */
619                                   /*      0x0010    unused */
620                                   /*      0x0020    unused */
621 #define PNG_FLAG_ROW_INIT                 0x0040
622 #define PNG_FLAG_FILLER_AFTER             0x0080
623 #define PNG_FLAG_CRC_ANCILLARY_USE        0x0100
624 #define PNG_FLAG_CRC_ANCILLARY_NOWARN     0x0200
625 #define PNG_FLAG_CRC_CRITICAL_USE         0x0400
626 #define PNG_FLAG_CRC_CRITICAL_IGNORE      0x0800
627 #define PNG_FLAG_ASSUME_sRGB              0x1000 /* Added to libpng-1.5.4 */
628 #define PNG_FLAG_OPTIMIZE_ALPHA           0x2000 /* Added to libpng-1.5.4 */
629 #define PNG_FLAG_DETECT_UNINITIALIZED     0x4000 /* Added to libpng-1.5.4 */
630 /* #define PNG_FLAG_KEEP_UNKNOWN_CHUNKS      0x8000 */
631 /* #define PNG_FLAG_KEEP_UNSAFE_CHUNKS      0x10000 */
632 #define PNG_FLAG_LIBRARY_MISMATCH        0x20000
633 #define PNG_FLAG_STRIP_ERROR_NUMBERS     0x40000
634 #define PNG_FLAG_STRIP_ERROR_TEXT        0x80000
635 #define PNG_FLAG_BENIGN_ERRORS_WARN     0x100000 /* Added to libpng-1.4.0 */
636 #define PNG_FLAG_APP_WARNINGS_WARN      0x200000 /* Added to libpng-1.6.0 */
637 #define PNG_FLAG_APP_ERRORS_WARN        0x400000 /* Added to libpng-1.6.0 */
638                                   /*    0x800000    unused */
639                                   /*   0x1000000    unused */
640                                   /*   0x2000000    unused */
641                                   /*   0x4000000    unused */
642                                   /*   0x8000000    unused */
643                                   /*  0x10000000    unused */
644                                   /*  0x20000000    unused */
645                                   /*  0x40000000    unused */
646 
647 #define PNG_FLAG_CRC_ANCILLARY_MASK (PNG_FLAG_CRC_ANCILLARY_USE | \
648                                      PNG_FLAG_CRC_ANCILLARY_NOWARN)
649 
650 #define PNG_FLAG_CRC_CRITICAL_MASK  (PNG_FLAG_CRC_CRITICAL_USE | \
651                                      PNG_FLAG_CRC_CRITICAL_IGNORE)
652 
653 #define PNG_FLAG_CRC_MASK           (PNG_FLAG_CRC_ANCILLARY_MASK | \
654                                      PNG_FLAG_CRC_CRITICAL_MASK)
655 
656 /* Save typing and make code easier to understand */
657 
658 #define PNG_COLOR_DIST(c1, c2) (abs((int)((c1).red) - (int)((c2).red)) + \
659    abs((int)((c1).green) - (int)((c2).green)) + \
660    abs((int)((c1).blue) - (int)((c2).blue)))
661 
662 /* Added to libpng-1.6.0: scale a 16-bit value in the range 0..65535 to 0..255
663  * by dividing by 257 *with rounding*.  This macro is exact for the given range.
664  * See the discourse in pngrtran.c png_do_scale_16_to_8.  The values in the
665  * macro were established by experiment (modifying the added value).  The macro
666  * has a second variant that takes a value already scaled by 255 and divides by
667  * 65535 - this has a maximum error of .502.  Over the range 0..65535*65535 it
668  * only gives off-by-one errors and only for 0.5% (1 in 200) of the values.
669  */
670 #define PNG_DIV65535(v24) (((v24) + 32895) >> 16)
671 #define PNG_DIV257(v16) PNG_DIV65535((png_uint_32)(v16) * 255)
672 
673 /* Added to libpng-1.2.6 JB */
674 #define PNG_ROWBYTES(pixel_bits, width) \
675     ((pixel_bits) >= 8 ? \
676     ((png_size_t)(width) * (((png_size_t)(pixel_bits)) >> 3)) : \
677     (( ((png_size_t)(width) * ((png_size_t)(pixel_bits))) + 7) >> 3) )
678 
679 /* PNG_OUT_OF_RANGE returns true if value is outside the range
680  * ideal-delta..ideal+delta.  Each argument is evaluated twice.
681  * "ideal" and "delta" should be constants, normally simple
682  * integers, "value" a variable. Added to libpng-1.2.6 JB
683  */
684 #define PNG_OUT_OF_RANGE(value, ideal, delta) \
685    ( (value) < (ideal)-(delta) || (value) > (ideal)+(delta) )
686 
687 /* Conversions between fixed and floating point, only defined if
688  * required (to make sure the code doesn't accidentally use float
689  * when it is supposedly disabled.)
690  */
691 #ifdef PNG_FLOATING_POINT_SUPPORTED
692 /* The floating point conversion can't overflow, though it can and
693  * does lose accuracy relative to the original fixed point value.
694  * In practice this doesn't matter because png_fixed_point only
695  * stores numbers with very low precision.  The png_ptr and s
696  * arguments are unused by default but are there in case error
697  * checking becomes a requirement.
698  */
699 #define png_float(png_ptr, fixed, s) (.00001 * (fixed))
700 
701 /* The fixed point conversion performs range checking and evaluates
702  * its argument multiple times, so must be used with care.  The
703  * range checking uses the PNG specification values for a signed
704  * 32-bit fixed point value except that the values are deliberately
705  * rounded-to-zero to an integral value - 21474 (21474.83 is roughly
706  * (2^31-1) * 100000). 's' is a string that describes the value being
707  * converted.
708  *
709  * NOTE: this macro will raise a png_error if the range check fails,
710  * therefore it is normally only appropriate to use this on values
711  * that come from API calls or other sources where an out of range
712  * error indicates a programming error, not a data error!
713  *
714  * NOTE: by default this is off - the macro is not used - because the
715  * function call saves a lot of code.
716  */
717 #ifdef PNG_FIXED_POINT_MACRO_SUPPORTED
718 #define png_fixed(png_ptr, fp, s) ((fp) <= 21474 && (fp) >= -21474 ?\
719     ((png_fixed_point)(100000 * (fp))) : (png_fixed_error(png_ptr, s),0))
720 #endif
721 /* else the corresponding function is defined below, inside the scope of the
722  * cplusplus test.
723  */
724 #endif
725 
726 /* Constants for known chunk types.  If you need to add a chunk, define the name
727  * here.  For historical reasons these constants have the form png_<name>; i.e.
728  * the prefix is lower case.  Please use decimal values as the parameters to
729  * match the ISO PNG specification and to avoid relying on the C locale
730  * interpretation of character values.
731  *
732  * Prior to 1.5.6 these constants were strings, as of 1.5.6 png_uint_32 values
733  * are computed and a new macro (PNG_STRING_FROM_CHUNK) added to allow a string
734  * to be generated if required.
735  *
736  * PNG_32b correctly produces a value shifted by up to 24 bits, even on
737  * architectures where (int) is only 16 bits.
738  */
739 #define PNG_32b(b,s) ((png_uint_32)(b) << (s))
740 #define PNG_U32(b1,b2,b3,b4) \
741    (PNG_32b(b1,24) | PNG_32b(b2,16) | PNG_32b(b3,8) | PNG_32b(b4,0))
742 
743 /* Constants for known chunk types.
744  *
745  * MAINTAINERS: If you need to add a chunk, define the name here.
746  * For historical reasons these constants have the form png_<name>; i.e.
747  * the prefix is lower case.  Please use decimal values as the parameters to
748  * match the ISO PNG specification and to avoid relying on the C locale
749  * interpretation of character values.  Please keep the list sorted.
750  *
751  * Notice that PNG_U32 is used to define a 32-bit value for the 4 byte chunk
752  * type.  In fact the specification does not express chunk types this way,
753  * however using a 32-bit value means that the chunk type can be read from the
754  * stream using exactly the same code as used for a 32-bit unsigned value and
755  * can be examined far more efficiently (using one arithmetic compare).
756  *
757  * Prior to 1.5.6 the chunk type constants were expressed as C strings.  The
758  * libpng API still uses strings for 'unknown' chunks and a macro,
759  * PNG_STRING_FROM_CHUNK, allows a string to be generated if required.  Notice
760  * that for portable code numeric values must still be used; the string "IHDR"
761  * is not portable and neither is PNG_U32('I', 'H', 'D', 'R').
762  *
763  * In 1.7.0 the definitions will be made public in png.h to avoid having to
764  * duplicate the same definitions in application code.
765  */
766 #define png_IDAT PNG_U32( 73,  68,  65,  84)
767 #define png_IEND PNG_U32( 73,  69,  78,  68)
768 #define png_IHDR PNG_U32( 73,  72,  68,  82)
769 #define png_PLTE PNG_U32( 80,  76,  84,  69)
770 #define png_bKGD PNG_U32( 98,  75,  71,  68)
771 #define png_cHRM PNG_U32( 99,  72,  82,  77)
772 #define png_fRAc PNG_U32(102,  82,  65,  99) /* registered, not defined */
773 #define png_gAMA PNG_U32(103,  65,  77,  65)
774 #define png_gIFg PNG_U32(103,  73,  70, 103)
775 #define png_gIFt PNG_U32(103,  73,  70, 116) /* deprecated */
776 #define png_gIFx PNG_U32(103,  73,  70, 120)
777 #define png_hIST PNG_U32(104,  73,  83,  84)
778 #define png_iCCP PNG_U32(105,  67,  67,  80)
779 #define png_iTXt PNG_U32(105,  84,  88, 116)
780 #define png_oFFs PNG_U32(111,  70,  70, 115)
781 #define png_pCAL PNG_U32(112,  67,  65,  76)
782 #define png_pHYs PNG_U32(112,  72,  89, 115)
783 #define png_sBIT PNG_U32(115,  66,  73,  84)
784 #define png_sCAL PNG_U32(115,  67,  65,  76)
785 #define png_sPLT PNG_U32(115,  80,  76,  84)
786 #define png_sRGB PNG_U32(115,  82,  71,  66)
787 #define png_sTER PNG_U32(115,  84,  69,  82)
788 #define png_tEXt PNG_U32(116,  69,  88, 116)
789 #define png_tIME PNG_U32(116,  73,  77,  69)
790 #define png_tRNS PNG_U32(116,  82,  78,  83)
791 #define png_zTXt PNG_U32(122,  84,  88, 116)
792 
793 /* The following will work on (signed char*) strings, whereas the get_uint_32
794  * macro will fail on top-bit-set values because of the sign extension.
795  */
796 #define PNG_CHUNK_FROM_STRING(s)\
797    PNG_U32(0xff & (s)[0], 0xff & (s)[1], 0xff & (s)[2], 0xff & (s)[3])
798 
799 /* This uses (char), not (png_byte) to avoid warnings on systems where (char) is
800  * signed and the argument is a (char[])  This macro will fail miserably on
801  * systems where (char) is more than 8 bits.
802  */
803 #define PNG_STRING_FROM_CHUNK(s,c)\
804    (void)(((char*)(s))[0]=(char)(((c)>>24) & 0xff), \
805    ((char*)(s))[1]=(char)(((c)>>16) & 0xff),\
806    ((char*)(s))[2]=(char)(((c)>>8) & 0xff), \
807    ((char*)(s))[3]=(char)((c & 0xff)))
808 
809 /* Do the same but terminate with a null character. */
810 #define PNG_CSTRING_FROM_CHUNK(s,c)\
811    (void)(PNG_STRING_FROM_CHUNK(s,c), ((char*)(s))[4] = 0)
812 
813 /* Test on flag values as defined in the spec (section 5.4): */
814 #define PNG_CHUNK_ANCILLARY(c)   (1 & ((c) >> 29))
815 #define PNG_CHUNK_CRITICAL(c)     (!PNG_CHUNK_ANCILLARY(c))
816 #define PNG_CHUNK_PRIVATE(c)      (1 & ((c) >> 21))
817 #define PNG_CHUNK_RESERVED(c)     (1 & ((c) >> 13))
818 #define PNG_CHUNK_SAFE_TO_COPY(c) (1 & ((c) >>  5))
819 
820 /* Gamma values (new at libpng-1.5.4): */
821 #define PNG_GAMMA_MAC_OLD 151724  /* Assume '1.8' is really 2.2/1.45! */
822 #define PNG_GAMMA_MAC_INVERSE 65909
823 #define PNG_GAMMA_sRGB_INVERSE 45455
824 
825 /* Almost everything below is C specific; the #defines above can be used in
826  * non-C code (so long as it is C-preprocessed) the rest of this stuff cannot.
827  */
828 #ifndef PNG_VERSION_INFO_ONLY
829 
830 #include "pngstruct.h"
831 #include "pnginfo.h"
832 
833 /* Validate the include paths - the include path used to generate pnglibconf.h
834  * must match that used in the build, or we must be using pnglibconf.h.prebuilt:
835  */
836 #if PNG_ZLIB_VERNUM != 0 && PNG_ZLIB_VERNUM != ZLIB_VERNUM
837 #  error ZLIB_VERNUM != PNG_ZLIB_VERNUM \
838       "-I (include path) error: see the notes in pngpriv.h"
839    /* This means that when pnglibconf.h was built the copy of zlib.h that it
840     * used is not the same as the one being used here.  Because the build of
841     * libpng makes decisions to use inflateInit2 and inflateReset2 based on the
842     * zlib version number and because this affects handling of certain broken
843     * PNG files the -I directives must match.
844     *
845     * The most likely explanation is that you passed a -I in CFLAGS. This will
846     * not work; all the preprocessor directories and in particular all the -I
847     * directives must be in CPPFLAGS.
848     */
849 #endif
850 
851 /* This is used for 16-bit gamma tables -- only the top level pointers are
852  * const; this could be changed:
853  */
854 typedef const png_uint_16p * png_const_uint_16pp;
855 
856 /* Added to libpng-1.5.7: sRGB conversion tables */
857 #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
858    defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
859 #ifdef PNG_SIMPLIFIED_READ_SUPPORTED
860 PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_table, [256]);
861    /* Convert from an sRGB encoded value 0..255 to a 16-bit linear value,
862     * 0..65535.  This table gives the closest 16-bit answers (no errors).
863     */
864 #endif
865 
866 PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_base, [512]);
867 PNG_INTERNAL_DATA(const png_byte, png_sRGB_delta, [512]);
868 
869 #define PNG_sRGB_FROM_LINEAR(linear) \
870   ((png_byte)(0xff & ((png_sRGB_base[(linear)>>15] \
871    + ((((linear) & 0x7fff)*png_sRGB_delta[(linear)>>15])>>12)) >> 8)))
872    /* Given a value 'linear' in the range 0..255*65535 calculate the 8-bit sRGB
873     * encoded value with maximum error 0.646365.  Note that the input is not a
874     * 16-bit value; it has been multiplied by 255! */
875 #endif /* SIMPLIFIED_READ/WRITE */
876 
877 
878 /* Inhibit C++ name-mangling for libpng functions but not for system calls. */
879 #ifdef __cplusplus
880 extern "C" {
881 #endif /* __cplusplus */
882 
883 /* Internal functions; these are not exported from a DLL however because they
884  * are used within several of the C source files they have to be C extern.
885  *
886  * All of these functions must be declared with PNG_INTERNAL_FUNCTION.
887  */
888 
889 /* Zlib support */
890 #define PNG_UNEXPECTED_ZLIB_RETURN (-7)
891 PNG_INTERNAL_FUNCTION(void, png_zstream_error,(png_structrp png_ptr, int ret),
892    PNG_EMPTY);
893    /* Used by the zlib handling functions to ensure that z_stream::msg is always
894     * set before they return.
895     */
896 
897 #ifdef PNG_WRITE_SUPPORTED
898 PNG_INTERNAL_FUNCTION(void,png_free_buffer_list,(png_structrp png_ptr,
899    png_compression_bufferp *list),PNG_EMPTY);
900    /* Free the buffer list used by the compressed write code. */
901 #endif
902 
903 #if defined(PNG_FLOATING_POINT_SUPPORTED) && \
904    !defined(PNG_FIXED_POINT_MACRO_SUPPORTED) && \
905    (defined(PNG_gAMA_SUPPORTED) || defined(PNG_cHRM_SUPPORTED) || \
906    defined(PNG_sCAL_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) || \
907    defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)) || \
908    (defined(PNG_sCAL_SUPPORTED) && \
909    defined(PNG_FLOATING_ARITHMETIC_SUPPORTED))
910 PNG_INTERNAL_FUNCTION(png_fixed_point,png_fixed,(png_const_structrp png_ptr,
911    double fp, png_const_charp text),PNG_EMPTY);
912 #endif
913 
914 /* Check the user version string for compatibility, returns false if the version
915  * numbers aren't compatible.
916  */
917 PNG_INTERNAL_FUNCTION(int,png_user_version_check,(png_structrp png_ptr,
918    png_const_charp user_png_ver),PNG_EMPTY);
919 
920 /* Internal base allocator - no messages, NULL on failure to allocate.  This
921  * does, however, call the application provided allocator and that could call
922  * png_error (although that would be a bug in the application implementation.)
923  */
924 PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_base,(png_const_structrp png_ptr,
925    png_alloc_size_t size),PNG_ALLOCATED);
926 
927 #if defined(PNG_TEXT_SUPPORTED) || defined(PNG_sPLT_SUPPORTED) ||\
928    defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED)
929 /* Internal array allocator, outputs no error or warning messages on failure,
930  * just returns NULL.
931  */
932 PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_array,(png_const_structrp png_ptr,
933    int nelements, size_t element_size),PNG_ALLOCATED);
934 
935 /* The same but an existing array is extended by add_elements.  This function
936  * also memsets the new elements to 0 and copies the old elements.  The old
937  * array is not freed or altered.
938  */
939 PNG_INTERNAL_FUNCTION(png_voidp,png_realloc_array,(png_const_structrp png_ptr,
940    png_const_voidp array, int old_elements, int add_elements,
941    size_t element_size),PNG_ALLOCATED);
942 #endif /* text, sPLT or unknown chunks */
943 
944 /* Magic to create a struct when there is no struct to call the user supplied
945  * memory allocators.  Because error handling has not been set up the memory
946  * handlers can't safely call png_error, but this is an obscure and undocumented
947  * restriction so libpng has to assume that the 'free' handler, at least, might
948  * call png_error.
949  */
950 PNG_INTERNAL_FUNCTION(png_structp,png_create_png_struct,
951    (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
952     png_error_ptr warn_fn, png_voidp mem_ptr, png_malloc_ptr malloc_fn,
953     png_free_ptr free_fn),PNG_ALLOCATED);
954 
955 /* Free memory from internal libpng struct */
956 PNG_INTERNAL_FUNCTION(void,png_destroy_png_struct,(png_structrp png_ptr),
957    PNG_EMPTY);
958 
959 /* Free an allocated jmp_buf (always succeeds) */
960 PNG_INTERNAL_FUNCTION(void,png_free_jmpbuf,(png_structrp png_ptr),PNG_EMPTY);
961 
962 /* Function to allocate memory for zlib.  PNGAPI is disallowed. */
963 PNG_INTERNAL_FUNCTION(voidpf,png_zalloc,(voidpf png_ptr, uInt items, uInt size),
964    PNG_ALLOCATED);
965 
966 /* Function to free memory for zlib.  PNGAPI is disallowed. */
967 PNG_INTERNAL_FUNCTION(void,png_zfree,(voidpf png_ptr, voidpf ptr),PNG_EMPTY);
968 
969 /* Next four functions are used internally as callbacks.  PNGCBAPI is required
970  * but not PNG_EXPORT.  PNGAPI added at libpng version 1.2.3, changed to
971  * PNGCBAPI at 1.5.0
972  */
973 
974 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_read_data,(png_structp png_ptr,
975     png_bytep data, png_size_t length),PNG_EMPTY);
976 
977 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
978 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_push_fill_buffer,(png_structp png_ptr,
979     png_bytep buffer, png_size_t length),PNG_EMPTY);
980 #endif
981 
982 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_write_data,(png_structp png_ptr,
983     png_bytep data, png_size_t length),PNG_EMPTY);
984 
985 #ifdef PNG_WRITE_FLUSH_SUPPORTED
986 #  ifdef PNG_STDIO_SUPPORTED
987 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_flush,(png_structp png_ptr),
988    PNG_EMPTY);
989 #  endif
990 #endif
991 
992 /* Reset the CRC variable */
993 PNG_INTERNAL_FUNCTION(void,png_reset_crc,(png_structrp png_ptr),PNG_EMPTY);
994 
995 /* Write the "data" buffer to whatever output you are using */
996 PNG_INTERNAL_FUNCTION(void,png_write_data,(png_structrp png_ptr,
997     png_const_bytep data, png_size_t length),PNG_EMPTY);
998 
999 /* Read and check the PNG file signature */
1000 PNG_INTERNAL_FUNCTION(void,png_read_sig,(png_structrp png_ptr,
1001    png_inforp info_ptr),PNG_EMPTY);
1002 
1003 /* Read the chunk header (length + type name) */
1004 PNG_INTERNAL_FUNCTION(png_uint_32,png_read_chunk_header,(png_structrp png_ptr),
1005    PNG_EMPTY);
1006 
1007 /* Read data from whatever input you are using into the "data" buffer */
1008 PNG_INTERNAL_FUNCTION(void,png_read_data,(png_structrp png_ptr, png_bytep data,
1009     png_size_t length),PNG_EMPTY);
1010 
1011 /* Read bytes into buf, and update png_ptr->crc */
1012 PNG_INTERNAL_FUNCTION(void,png_crc_read,(png_structrp png_ptr, png_bytep buf,
1013     png_uint_32 length),PNG_EMPTY);
1014 
1015 /* Read "skip" bytes, read the file crc, and (optionally) verify png_ptr->crc */
1016 PNG_INTERNAL_FUNCTION(int,png_crc_finish,(png_structrp png_ptr,
1017    png_uint_32 skip),PNG_EMPTY);
1018 
1019 /* Read the CRC from the file and compare it to the libpng calculated CRC */
1020 PNG_INTERNAL_FUNCTION(int,png_crc_error,(png_structrp png_ptr),PNG_EMPTY);
1021 
1022 /* Calculate the CRC over a section of data.  Note that we are only
1023  * passing a maximum of 64K on systems that have this as a memory limit,
1024  * since this is the maximum buffer size we can specify.
1025  */
1026 PNG_INTERNAL_FUNCTION(void,png_calculate_crc,(png_structrp png_ptr,
1027    png_const_bytep ptr, png_size_t length),PNG_EMPTY);
1028 
1029 #ifdef PNG_WRITE_FLUSH_SUPPORTED
1030 PNG_INTERNAL_FUNCTION(void,png_flush,(png_structrp png_ptr),PNG_EMPTY);
1031 #endif
1032 
1033 /* Write various chunks */
1034 
1035 /* Write the IHDR chunk, and update the png_struct with the necessary
1036  * information.
1037  */
1038 PNG_INTERNAL_FUNCTION(void,png_write_IHDR,(png_structrp png_ptr,
1039    png_uint_32 width, png_uint_32 height, int bit_depth, int color_type,
1040    int compression_method, int filter_method, int interlace_method),PNG_EMPTY);
1041 
1042 PNG_INTERNAL_FUNCTION(void,png_write_PLTE,(png_structrp png_ptr,
1043    png_const_colorp palette, png_uint_32 num_pal),PNG_EMPTY);
1044 
1045 PNG_INTERNAL_FUNCTION(void,png_compress_IDAT,(png_structrp png_ptr,
1046    png_const_bytep row_data, png_alloc_size_t row_data_length, int flush),
1047    PNG_EMPTY);
1048 
1049 PNG_INTERNAL_FUNCTION(void,png_write_IEND,(png_structrp png_ptr),PNG_EMPTY);
1050 
1051 #ifdef PNG_WRITE_gAMA_SUPPORTED
1052 PNG_INTERNAL_FUNCTION(void,png_write_gAMA_fixed,(png_structrp png_ptr,
1053     png_fixed_point file_gamma),PNG_EMPTY);
1054 #endif
1055 
1056 #ifdef PNG_WRITE_sBIT_SUPPORTED
1057 PNG_INTERNAL_FUNCTION(void,png_write_sBIT,(png_structrp png_ptr,
1058     png_const_color_8p sbit, int color_type),PNG_EMPTY);
1059 #endif
1060 
1061 #ifdef PNG_WRITE_cHRM_SUPPORTED
1062 PNG_INTERNAL_FUNCTION(void,png_write_cHRM_fixed,(png_structrp png_ptr,
1063     const png_xy *xy), PNG_EMPTY);
1064     /* The xy value must have been previously validated */
1065 #endif
1066 
1067 #ifdef PNG_WRITE_sRGB_SUPPORTED
1068 PNG_INTERNAL_FUNCTION(void,png_write_sRGB,(png_structrp png_ptr,
1069     int intent),PNG_EMPTY);
1070 #endif
1071 
1072 #ifdef PNG_WRITE_iCCP_SUPPORTED
1073 PNG_INTERNAL_FUNCTION(void,png_write_iCCP,(png_structrp png_ptr,
1074    png_const_charp name, png_const_bytep profile), PNG_EMPTY);
1075    /* The profile must have been previously validated for correctness, the
1076     * length comes from the first four bytes.  Only the base, deflate,
1077     * compression is supported.
1078     */
1079 #endif
1080 
1081 #ifdef PNG_WRITE_sPLT_SUPPORTED
1082 PNG_INTERNAL_FUNCTION(void,png_write_sPLT,(png_structrp png_ptr,
1083     png_const_sPLT_tp palette),PNG_EMPTY);
1084 #endif
1085 
1086 #ifdef PNG_WRITE_tRNS_SUPPORTED
1087 PNG_INTERNAL_FUNCTION(void,png_write_tRNS,(png_structrp png_ptr,
1088     png_const_bytep trans, png_const_color_16p values, int number,
1089     int color_type),PNG_EMPTY);
1090 #endif
1091 
1092 #ifdef PNG_WRITE_bKGD_SUPPORTED
1093 PNG_INTERNAL_FUNCTION(void,png_write_bKGD,(png_structrp png_ptr,
1094     png_const_color_16p values, int color_type),PNG_EMPTY);
1095 #endif
1096 
1097 #ifdef PNG_WRITE_hIST_SUPPORTED
1098 PNG_INTERNAL_FUNCTION(void,png_write_hIST,(png_structrp png_ptr,
1099     png_const_uint_16p hist, int num_hist),PNG_EMPTY);
1100 #endif
1101 
1102 /* Chunks that have keywords */
1103 #ifdef PNG_WRITE_tEXt_SUPPORTED
1104 PNG_INTERNAL_FUNCTION(void,png_write_tEXt,(png_structrp png_ptr,
1105    png_const_charp key, png_const_charp text, png_size_t text_len),PNG_EMPTY);
1106 #endif
1107 
1108 #ifdef PNG_WRITE_zTXt_SUPPORTED
1109 PNG_INTERNAL_FUNCTION(void,png_write_zTXt,(png_structrp png_ptr, png_const_charp
1110     key, png_const_charp text, int compression),PNG_EMPTY);
1111 #endif
1112 
1113 #ifdef PNG_WRITE_iTXt_SUPPORTED
1114 PNG_INTERNAL_FUNCTION(void,png_write_iTXt,(png_structrp png_ptr,
1115     int compression, png_const_charp key, png_const_charp lang,
1116     png_const_charp lang_key, png_const_charp text),PNG_EMPTY);
1117 #endif
1118 
1119 #ifdef PNG_TEXT_SUPPORTED  /* Added at version 1.0.14 and 1.2.4 */
1120 PNG_INTERNAL_FUNCTION(int,png_set_text_2,(png_const_structrp png_ptr,
1121     png_inforp info_ptr, png_const_textp text_ptr, int num_text),PNG_EMPTY);
1122 #endif
1123 
1124 #ifdef PNG_WRITE_oFFs_SUPPORTED
1125 PNG_INTERNAL_FUNCTION(void,png_write_oFFs,(png_structrp png_ptr,
1126     png_int_32 x_offset, png_int_32 y_offset, int unit_type),PNG_EMPTY);
1127 #endif
1128 
1129 #ifdef PNG_WRITE_pCAL_SUPPORTED
1130 PNG_INTERNAL_FUNCTION(void,png_write_pCAL,(png_structrp png_ptr,
1131     png_charp purpose, png_int_32 X0, png_int_32 X1, int type, int nparams,
1132     png_const_charp units, png_charpp params),PNG_EMPTY);
1133 #endif
1134 
1135 #ifdef PNG_WRITE_pHYs_SUPPORTED
1136 PNG_INTERNAL_FUNCTION(void,png_write_pHYs,(png_structrp png_ptr,
1137     png_uint_32 x_pixels_per_unit, png_uint_32 y_pixels_per_unit,
1138     int unit_type),PNG_EMPTY);
1139 #endif
1140 
1141 #ifdef PNG_WRITE_tIME_SUPPORTED
1142 PNG_INTERNAL_FUNCTION(void,png_write_tIME,(png_structrp png_ptr,
1143     png_const_timep mod_time),PNG_EMPTY);
1144 #endif
1145 
1146 #ifdef PNG_WRITE_sCAL_SUPPORTED
1147 PNG_INTERNAL_FUNCTION(void,png_write_sCAL_s,(png_structrp png_ptr,
1148     int unit, png_const_charp width, png_const_charp height),PNG_EMPTY);
1149 #endif
1150 
1151 /* Called when finished processing a row of data */
1152 PNG_INTERNAL_FUNCTION(void,png_write_finish_row,(png_structrp png_ptr),
1153     PNG_EMPTY);
1154 
1155 /* Internal use only.   Called before first row of data */
1156 PNG_INTERNAL_FUNCTION(void,png_write_start_row,(png_structrp png_ptr),
1157     PNG_EMPTY);
1158 
1159 /* Combine a row of data, dealing with alpha, etc. if requested.  'row' is an
1160  * array of png_ptr->width pixels.  If the image is not interlaced or this
1161  * is the final pass this just does a memcpy, otherwise the "display" flag
1162  * is used to determine whether to copy pixels that are not in the current pass.
1163  *
1164  * Because 'png_do_read_interlace' (below) replicates pixels this allows this
1165  * function to achieve the documented 'blocky' appearance during interlaced read
1166  * if display is 1 and the 'sparkle' appearance, where existing pixels in 'row'
1167  * are not changed if they are not in the current pass, when display is 0.
1168  *
1169  * 'display' must be 0 or 1, otherwise the memcpy will be done regardless.
1170  *
1171  * The API always reads from the png_struct row buffer and always assumes that
1172  * it is full width (png_do_read_interlace has already been called.)
1173  *
1174  * This function is only ever used to write to row buffers provided by the
1175  * caller of the relevant libpng API and the row must have already been
1176  * transformed by the read transformations.
1177  *
1178  * The PNG_USE_COMPILE_TIME_MASKS option causes generation of pre-computed
1179  * bitmasks for use within the code, otherwise runtime generated masks are used.
1180  * The default is compile time masks.
1181  */
1182 #ifndef PNG_USE_COMPILE_TIME_MASKS
1183 #  define PNG_USE_COMPILE_TIME_MASKS 1
1184 #endif
1185 PNG_INTERNAL_FUNCTION(void,png_combine_row,(png_const_structrp png_ptr,
1186     png_bytep row, int display),PNG_EMPTY);
1187 
1188 #ifdef PNG_READ_INTERLACING_SUPPORTED
1189 /* Expand an interlaced row: the 'row_info' describes the pass data that has
1190  * been read in and must correspond to the pixels in 'row', the pixels are
1191  * expanded (moved apart) in 'row' to match the final layout, when doing this
1192  * the pixels are *replicated* to the intervening space.  This is essential for
1193  * the correct operation of png_combine_row, above.
1194  */
1195 PNG_INTERNAL_FUNCTION(void,png_do_read_interlace,(png_row_infop row_info,
1196     png_bytep row, int pass, png_uint_32 transformations),PNG_EMPTY);
1197 #endif
1198 
1199 /* GRR TO DO (2.0 or whenever):  simplify other internal calling interfaces */
1200 
1201 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1202 /* Grab pixels out of a row for an interlaced pass */
1203 PNG_INTERNAL_FUNCTION(void,png_do_write_interlace,(png_row_infop row_info,
1204     png_bytep row, int pass),PNG_EMPTY);
1205 #endif
1206 
1207 /* Unfilter a row: check the filter value before calling this, there is no point
1208  * calling it for PNG_FILTER_VALUE_NONE.
1209  */
1210 PNG_INTERNAL_FUNCTION(void,png_read_filter_row,(png_structrp pp, png_row_infop
1211     row_info, png_bytep row, png_const_bytep prev_row, int filter),PNG_EMPTY);
1212 
1213 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_up_neon,(png_row_infop row_info,
1214     png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1215 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_neon,(png_row_infop
1216     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1217 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_neon,(png_row_infop
1218     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1219 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_neon,(png_row_infop
1220     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1221 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_neon,(png_row_infop
1222     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1223 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_neon,(png_row_infop
1224     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1225 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_neon,(png_row_infop
1226     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1227 
1228 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_sse2,(png_row_infop
1229     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1230 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_sse2,(png_row_infop
1231     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1232 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_sse2,(png_row_infop
1233     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1234 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_sse2,(png_row_infop
1235     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1236 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_sse2,(png_row_infop
1237     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1238 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_sse2,(png_row_infop
1239     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1240 
1241 /* Choose the best filter to use and filter the row data */
1242 PNG_INTERNAL_FUNCTION(void,png_write_find_filter,(png_structrp png_ptr,
1243     png_row_infop row_info),PNG_EMPTY);
1244 
1245 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1246 PNG_INTERNAL_FUNCTION(void,png_read_IDAT_data,(png_structrp png_ptr,
1247    png_bytep output, png_alloc_size_t avail_out),PNG_EMPTY);
1248    /* Read 'avail_out' bytes of data from the IDAT stream.  If the output buffer
1249     * is NULL the function checks, instead, for the end of the stream.  In this
1250     * case a benign error will be issued if the stream end is not found or if
1251     * extra data has to be consumed.
1252     */
1253 PNG_INTERNAL_FUNCTION(void,png_read_finish_IDAT,(png_structrp png_ptr),
1254    PNG_EMPTY);
1255    /* This cleans up when the IDAT LZ stream does not end when the last image
1256     * byte is read; there is still some pending input.
1257     */
1258 
1259 PNG_INTERNAL_FUNCTION(void,png_read_finish_row,(png_structrp png_ptr),
1260    PNG_EMPTY);
1261    /* Finish a row while reading, dealing with interlacing passes, etc. */
1262 #endif /* SEQUENTIAL_READ */
1263 
1264 /* Initialize the row buffers, etc. */
1265 PNG_INTERNAL_FUNCTION(void,png_read_start_row,(png_structrp png_ptr),PNG_EMPTY);
1266 
1267 #if PNG_ZLIB_VERNUM >= 0x1240
1268 PNG_INTERNAL_FUNCTION(int,png_zlib_inflate,(png_structrp png_ptr, int flush),
1269       PNG_EMPTY);
1270 #  define PNG_INFLATE(pp, flush) png_zlib_inflate(pp, flush)
1271 #else /* Zlib < 1.2.4 */
1272 #  define PNG_INFLATE(pp, flush) inflate(&(pp)->zstream, flush)
1273 #endif /* Zlib < 1.2.4 */
1274 
1275 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1276 /* Optional call to update the users info structure */
1277 PNG_INTERNAL_FUNCTION(void,png_read_transform_info,(png_structrp png_ptr,
1278     png_inforp info_ptr),PNG_EMPTY);
1279 #endif
1280 
1281 /* Shared transform functions, defined in pngtran.c */
1282 #if defined(PNG_WRITE_FILLER_SUPPORTED) || \
1283     defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
1284 PNG_INTERNAL_FUNCTION(void,png_do_strip_channel,(png_row_infop row_info,
1285     png_bytep row, int at_start),PNG_EMPTY);
1286 #endif
1287 
1288 #ifdef PNG_16BIT_SUPPORTED
1289 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
1290 PNG_INTERNAL_FUNCTION(void,png_do_swap,(png_row_infop row_info,
1291     png_bytep row),PNG_EMPTY);
1292 #endif
1293 #endif
1294 
1295 #if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
1296     defined(PNG_WRITE_PACKSWAP_SUPPORTED)
1297 PNG_INTERNAL_FUNCTION(void,png_do_packswap,(png_row_infop row_info,
1298     png_bytep row),PNG_EMPTY);
1299 #endif
1300 
1301 #if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
1302 PNG_INTERNAL_FUNCTION(void,png_do_invert,(png_row_infop row_info,
1303     png_bytep row),PNG_EMPTY);
1304 #endif
1305 
1306 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
1307 PNG_INTERNAL_FUNCTION(void,png_do_bgr,(png_row_infop row_info,
1308     png_bytep row),PNG_EMPTY);
1309 #endif
1310 
1311 /* The following decodes the appropriate chunks, and does error correction,
1312  * then calls the appropriate callback for the chunk if it is valid.
1313  */
1314 
1315 /* Decode the IHDR chunk */
1316 PNG_INTERNAL_FUNCTION(void,png_handle_IHDR,(png_structrp png_ptr,
1317     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1318 PNG_INTERNAL_FUNCTION(void,png_handle_PLTE,(png_structrp png_ptr,
1319     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1320 PNG_INTERNAL_FUNCTION(void,png_handle_IEND,(png_structrp png_ptr,
1321     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1322 
1323 #ifdef PNG_READ_bKGD_SUPPORTED
1324 PNG_INTERNAL_FUNCTION(void,png_handle_bKGD,(png_structrp png_ptr,
1325     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1326 #endif
1327 
1328 #ifdef PNG_READ_cHRM_SUPPORTED
1329 PNG_INTERNAL_FUNCTION(void,png_handle_cHRM,(png_structrp png_ptr,
1330     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1331 #endif
1332 
1333 #ifdef PNG_READ_gAMA_SUPPORTED
1334 PNG_INTERNAL_FUNCTION(void,png_handle_gAMA,(png_structrp png_ptr,
1335     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1336 #endif
1337 
1338 #ifdef PNG_READ_hIST_SUPPORTED
1339 PNG_INTERNAL_FUNCTION(void,png_handle_hIST,(png_structrp png_ptr,
1340     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1341 #endif
1342 
1343 #ifdef PNG_READ_iCCP_SUPPORTED
1344 PNG_INTERNAL_FUNCTION(void,png_handle_iCCP,(png_structrp png_ptr,
1345     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1346 #endif /* READ_iCCP */
1347 
1348 #ifdef PNG_READ_iTXt_SUPPORTED
1349 PNG_INTERNAL_FUNCTION(void,png_handle_iTXt,(png_structrp png_ptr,
1350     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1351 #endif
1352 
1353 #ifdef PNG_READ_oFFs_SUPPORTED
1354 PNG_INTERNAL_FUNCTION(void,png_handle_oFFs,(png_structrp png_ptr,
1355     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1356 #endif
1357 
1358 #ifdef PNG_READ_pCAL_SUPPORTED
1359 PNG_INTERNAL_FUNCTION(void,png_handle_pCAL,(png_structrp png_ptr,
1360     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1361 #endif
1362 
1363 #ifdef PNG_READ_pHYs_SUPPORTED
1364 PNG_INTERNAL_FUNCTION(void,png_handle_pHYs,(png_structrp png_ptr,
1365     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1366 #endif
1367 
1368 #ifdef PNG_READ_sBIT_SUPPORTED
1369 PNG_INTERNAL_FUNCTION(void,png_handle_sBIT,(png_structrp png_ptr,
1370     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1371 #endif
1372 
1373 #ifdef PNG_READ_sCAL_SUPPORTED
1374 PNG_INTERNAL_FUNCTION(void,png_handle_sCAL,(png_structrp png_ptr,
1375     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1376 #endif
1377 
1378 #ifdef PNG_READ_sPLT_SUPPORTED
1379 PNG_INTERNAL_FUNCTION(void,png_handle_sPLT,(png_structrp png_ptr,
1380     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1381 #endif /* READ_sPLT */
1382 
1383 #ifdef PNG_READ_sRGB_SUPPORTED
1384 PNG_INTERNAL_FUNCTION(void,png_handle_sRGB,(png_structrp png_ptr,
1385     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1386 #endif
1387 
1388 #ifdef PNG_READ_tEXt_SUPPORTED
1389 PNG_INTERNAL_FUNCTION(void,png_handle_tEXt,(png_structrp png_ptr,
1390     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1391 #endif
1392 
1393 #ifdef PNG_READ_tIME_SUPPORTED
1394 PNG_INTERNAL_FUNCTION(void,png_handle_tIME,(png_structrp png_ptr,
1395     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1396 #endif
1397 
1398 #ifdef PNG_READ_tRNS_SUPPORTED
1399 PNG_INTERNAL_FUNCTION(void,png_handle_tRNS,(png_structrp png_ptr,
1400     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1401 #endif
1402 
1403 #ifdef PNG_READ_zTXt_SUPPORTED
1404 PNG_INTERNAL_FUNCTION(void,png_handle_zTXt,(png_structrp png_ptr,
1405     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1406 #endif
1407 
1408 PNG_INTERNAL_FUNCTION(void,png_check_chunk_name,(png_structrp png_ptr,
1409     png_uint_32 chunk_name),PNG_EMPTY);
1410 
1411 PNG_INTERNAL_FUNCTION(void,png_handle_unknown,(png_structrp png_ptr,
1412     png_inforp info_ptr, png_uint_32 length, int keep),PNG_EMPTY);
1413    /* This is the function that gets called for unknown chunks.  The 'keep'
1414     * argument is either non-zero for a known chunk that has been set to be
1415     * handled as unknown or zero for an unknown chunk.  By default the function
1416     * just skips the chunk or errors out if it is critical.
1417     */
1418 
1419 #if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) ||\
1420     defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
1421 PNG_INTERNAL_FUNCTION(int,png_chunk_unknown_handling,
1422     (png_const_structrp png_ptr, png_uint_32 chunk_name),PNG_EMPTY);
1423    /* Exactly as the API png_handle_as_unknown() except that the argument is a
1424     * 32-bit chunk name, not a string.
1425     */
1426 #endif /* READ_UNKNOWN_CHUNKS || HANDLE_AS_UNKNOWN */
1427 
1428 /* Handle the transformations for reading and writing */
1429 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1430 PNG_INTERNAL_FUNCTION(void,png_do_read_transformations,(png_structrp png_ptr,
1431    png_row_infop row_info),PNG_EMPTY);
1432 #endif
1433 #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
1434 PNG_INTERNAL_FUNCTION(void,png_do_write_transformations,(png_structrp png_ptr,
1435    png_row_infop row_info),PNG_EMPTY);
1436 #endif
1437 
1438 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1439 PNG_INTERNAL_FUNCTION(void,png_init_read_transformations,(png_structrp png_ptr),
1440     PNG_EMPTY);
1441 #endif
1442 
1443 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1444 PNG_INTERNAL_FUNCTION(void,png_push_read_chunk,(png_structrp png_ptr,
1445     png_inforp info_ptr),PNG_EMPTY);
1446 PNG_INTERNAL_FUNCTION(void,png_push_read_sig,(png_structrp png_ptr,
1447     png_inforp info_ptr),PNG_EMPTY);
1448 PNG_INTERNAL_FUNCTION(void,png_push_check_crc,(png_structrp png_ptr),PNG_EMPTY);
1449 PNG_INTERNAL_FUNCTION(void,png_push_save_buffer,(png_structrp png_ptr),
1450     PNG_EMPTY);
1451 PNG_INTERNAL_FUNCTION(void,png_push_restore_buffer,(png_structrp png_ptr,
1452     png_bytep buffer, png_size_t buffer_length),PNG_EMPTY);
1453 PNG_INTERNAL_FUNCTION(void,png_push_read_IDAT,(png_structrp png_ptr),PNG_EMPTY);
1454 PNG_INTERNAL_FUNCTION(void,png_process_IDAT_data,(png_structrp png_ptr,
1455     png_bytep buffer, png_size_t buffer_length),PNG_EMPTY);
1456 PNG_INTERNAL_FUNCTION(void,png_push_process_row,(png_structrp png_ptr),
1457     PNG_EMPTY);
1458 PNG_INTERNAL_FUNCTION(void,png_push_handle_unknown,(png_structrp png_ptr,
1459    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1460 PNG_INTERNAL_FUNCTION(void,png_push_have_info,(png_structrp png_ptr,
1461    png_inforp info_ptr),PNG_EMPTY);
1462 PNG_INTERNAL_FUNCTION(void,png_push_have_end,(png_structrp png_ptr,
1463    png_inforp info_ptr),PNG_EMPTY);
1464 PNG_INTERNAL_FUNCTION(void,png_push_have_row,(png_structrp png_ptr,
1465      png_bytep row),PNG_EMPTY);
1466 PNG_INTERNAL_FUNCTION(void,png_push_read_end,(png_structrp png_ptr,
1467     png_inforp info_ptr),PNG_EMPTY);
1468 PNG_INTERNAL_FUNCTION(void,png_process_some_data,(png_structrp png_ptr,
1469     png_inforp info_ptr),PNG_EMPTY);
1470 PNG_INTERNAL_FUNCTION(void,png_read_push_finish_row,(png_structrp png_ptr),
1471     PNG_EMPTY);
1472 #  ifdef PNG_READ_tEXt_SUPPORTED
1473 PNG_INTERNAL_FUNCTION(void,png_push_handle_tEXt,(png_structrp png_ptr,
1474     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1475 PNG_INTERNAL_FUNCTION(void,png_push_read_tEXt,(png_structrp png_ptr,
1476     png_inforp info_ptr),PNG_EMPTY);
1477 #  endif
1478 #  ifdef PNG_READ_zTXt_SUPPORTED
1479 PNG_INTERNAL_FUNCTION(void,png_push_handle_zTXt,(png_structrp png_ptr,
1480     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1481 PNG_INTERNAL_FUNCTION(void,png_push_read_zTXt,(png_structrp png_ptr,
1482     png_inforp info_ptr),PNG_EMPTY);
1483 #  endif
1484 #  ifdef PNG_READ_iTXt_SUPPORTED
1485 PNG_INTERNAL_FUNCTION(void,png_push_handle_iTXt,(png_structrp png_ptr,
1486     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1487 PNG_INTERNAL_FUNCTION(void,png_push_read_iTXt,(png_structrp png_ptr,
1488     png_inforp info_ptr),PNG_EMPTY);
1489 #  endif
1490 
1491 #endif /* PROGRESSIVE_READ */
1492 
1493 /* Added at libpng version 1.6.0 */
1494 #ifdef PNG_GAMMA_SUPPORTED
1495 PNG_INTERNAL_FUNCTION(void,png_colorspace_set_gamma,(png_const_structrp png_ptr,
1496     png_colorspacerp colorspace, png_fixed_point gAMA), PNG_EMPTY);
1497    /* Set the colorspace gamma with a value provided by the application or by
1498     * the gAMA chunk on read.  The value will override anything set by an ICC
1499     * profile.
1500     */
1501 
1502 PNG_INTERNAL_FUNCTION(void,png_colorspace_sync_info,(png_const_structrp png_ptr,
1503     png_inforp info_ptr), PNG_EMPTY);
1504     /* Synchronize the info 'valid' flags with the colorspace */
1505 
1506 PNG_INTERNAL_FUNCTION(void,png_colorspace_sync,(png_const_structrp png_ptr,
1507     png_inforp info_ptr), PNG_EMPTY);
1508     /* Copy the png_struct colorspace to the info_struct and call the above to
1509      * synchronize the flags.  Checks for NULL info_ptr and does nothing.
1510      */
1511 #endif
1512 
1513 /* Added at libpng version 1.4.0 */
1514 #ifdef PNG_COLORSPACE_SUPPORTED
1515 /* These internal functions are for maintaining the colorspace structure within
1516  * a png_info or png_struct (or, indeed, both).
1517  */
1518 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_chromaticities,
1519    (png_const_structrp png_ptr, png_colorspacerp colorspace, const png_xy *xy,
1520     int preferred), PNG_EMPTY);
1521 
1522 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_endpoints,
1523    (png_const_structrp png_ptr, png_colorspacerp colorspace, const png_XYZ *XYZ,
1524     int preferred), PNG_EMPTY);
1525 
1526 #ifdef PNG_sRGB_SUPPORTED
1527 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_sRGB,(png_const_structrp png_ptr,
1528    png_colorspacerp colorspace, int intent), PNG_EMPTY);
1529    /* This does set the colorspace gAMA and cHRM values too, but doesn't set the
1530     * flags to write them, if it returns false there was a problem and an error
1531     * message has already been output (but the colorspace may still need to be
1532     * synced to record the invalid flag).
1533     */
1534 #endif /* sRGB */
1535 
1536 #ifdef PNG_iCCP_SUPPORTED
1537 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_ICC,(png_const_structrp png_ptr,
1538    png_colorspacerp colorspace, png_const_charp name,
1539    png_uint_32 profile_length, png_const_bytep profile, int color_type),
1540    PNG_EMPTY);
1541    /* The 'name' is used for information only */
1542 
1543 /* Routines for checking parts of an ICC profile. */
1544 PNG_INTERNAL_FUNCTION(int,png_icc_check_length,(png_const_structrp png_ptr,
1545    png_colorspacerp colorspace, png_const_charp name,
1546    png_uint_32 profile_length), PNG_EMPTY);
1547 PNG_INTERNAL_FUNCTION(int,png_icc_check_header,(png_const_structrp png_ptr,
1548    png_colorspacerp colorspace, png_const_charp name,
1549    png_uint_32 profile_length,
1550    png_const_bytep profile /* first 132 bytes only */, int color_type),
1551    PNG_EMPTY);
1552 PNG_INTERNAL_FUNCTION(int,png_icc_check_tag_table,(png_const_structrp png_ptr,
1553    png_colorspacerp colorspace, png_const_charp name,
1554    png_uint_32 profile_length,
1555    png_const_bytep profile /* header plus whole tag table */), PNG_EMPTY);
1556 #ifdef PNG_sRGB_SUPPORTED
1557 PNG_INTERNAL_FUNCTION(void,png_icc_set_sRGB,(
1558    png_const_structrp png_ptr, png_colorspacerp colorspace,
1559    png_const_bytep profile, uLong adler), PNG_EMPTY);
1560    /* 'adler' is the Adler32 checksum of the uncompressed profile data. It may
1561     * be zero to indicate that it is not available.  It is used, if provided,
1562     * as a fast check on the profile when checking to see if it is sRGB.
1563     */
1564 #endif
1565 #endif /* iCCP */
1566 
1567 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1568 PNG_INTERNAL_FUNCTION(void,png_colorspace_set_rgb_coefficients,
1569    (png_structrp png_ptr), PNG_EMPTY);
1570    /* Set the rgb_to_gray coefficients from the colorspace Y values */
1571 #endif /* READ_RGB_TO_GRAY */
1572 #endif /* COLORSPACE */
1573 
1574 /* Added at libpng version 1.4.0 */
1575 PNG_INTERNAL_FUNCTION(void,png_check_IHDR,(png_const_structrp png_ptr,
1576     png_uint_32 width, png_uint_32 height, int bit_depth,
1577     int color_type, int interlace_type, int compression_type,
1578     int filter_type),PNG_EMPTY);
1579 
1580 /* Added at libpng version 1.5.10 */
1581 #if defined(PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED) || \
1582     defined(PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED)
1583 PNG_INTERNAL_FUNCTION(void,png_do_check_palette_indexes,
1584    (png_structrp png_ptr, png_row_infop row_info),PNG_EMPTY);
1585 #endif
1586 
1587 #if defined(PNG_FLOATING_POINT_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED)
1588 PNG_INTERNAL_FUNCTION(void,png_fixed_error,(png_const_structrp png_ptr,
1589    png_const_charp name),PNG_NORETURN);
1590 #endif
1591 
1592 /* Puts 'string' into 'buffer' at buffer[pos], taking care never to overwrite
1593  * the end.  Always leaves the buffer nul terminated.  Never errors out (and
1594  * there is no error code.)
1595  */
1596 PNG_INTERNAL_FUNCTION(size_t,png_safecat,(png_charp buffer, size_t bufsize,
1597    size_t pos, png_const_charp string),PNG_EMPTY);
1598 
1599 /* Various internal functions to handle formatted warning messages, currently
1600  * only implemented for warnings.
1601  */
1602 #if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_TIME_RFC1123_SUPPORTED)
1603 /* Utility to dump an unsigned value into a buffer, given a start pointer and
1604  * and end pointer (which should point just *beyond* the end of the buffer!)
1605  * Returns the pointer to the start of the formatted string.  This utility only
1606  * does unsigned values.
1607  */
1608 PNG_INTERNAL_FUNCTION(png_charp,png_format_number,(png_const_charp start,
1609    png_charp end, int format, png_alloc_size_t number),PNG_EMPTY);
1610 
1611 /* Convenience macro that takes an array: */
1612 #define PNG_FORMAT_NUMBER(buffer,format,number) \
1613    png_format_number(buffer, buffer + (sizeof buffer), format, number)
1614 
1615 /* Suggested size for a number buffer (enough for 64 bits and a sign!) */
1616 #define PNG_NUMBER_BUFFER_SIZE 24
1617 
1618 /* These are the integer formats currently supported, the name is formed from
1619  * the standard printf(3) format string.
1620  */
1621 #define PNG_NUMBER_FORMAT_u     1 /* chose unsigned API! */
1622 #define PNG_NUMBER_FORMAT_02u   2
1623 #define PNG_NUMBER_FORMAT_d     1 /* chose signed API! */
1624 #define PNG_NUMBER_FORMAT_02d   2
1625 #define PNG_NUMBER_FORMAT_x     3
1626 #define PNG_NUMBER_FORMAT_02x   4
1627 #define PNG_NUMBER_FORMAT_fixed 5 /* choose the signed API */
1628 #endif
1629 
1630 #ifdef PNG_WARNINGS_SUPPORTED
1631 /* New defines and members adding in libpng-1.5.4 */
1632 #  define PNG_WARNING_PARAMETER_SIZE 32
1633 #  define PNG_WARNING_PARAMETER_COUNT 8 /* Maximum 9; see pngerror.c */
1634 
1635 /* An l-value of this type has to be passed to the APIs below to cache the
1636  * values of the parameters to a formatted warning message.
1637  */
1638 typedef char png_warning_parameters[PNG_WARNING_PARAMETER_COUNT][
1639    PNG_WARNING_PARAMETER_SIZE];
1640 
1641 PNG_INTERNAL_FUNCTION(void,png_warning_parameter,(png_warning_parameters p,
1642    int number, png_const_charp string),PNG_EMPTY);
1643    /* Parameters are limited in size to PNG_WARNING_PARAMETER_SIZE characters,
1644     * including the trailing '\0'.
1645     */
1646 PNG_INTERNAL_FUNCTION(void,png_warning_parameter_unsigned,
1647    (png_warning_parameters p, int number, int format, png_alloc_size_t value),
1648    PNG_EMPTY);
1649    /* Use png_alloc_size_t because it is an unsigned type as big as any we
1650     * need to output.  Use the following for a signed value.
1651     */
1652 PNG_INTERNAL_FUNCTION(void,png_warning_parameter_signed,
1653    (png_warning_parameters p, int number, int format, png_int_32 value),
1654    PNG_EMPTY);
1655 
1656 PNG_INTERNAL_FUNCTION(void,png_formatted_warning,(png_const_structrp png_ptr,
1657    png_warning_parameters p, png_const_charp message),PNG_EMPTY);
1658    /* 'message' follows the X/Open approach of using @1, @2 to insert
1659     * parameters previously supplied using the above functions.  Errors in
1660     * specifying the parameters will simply result in garbage substitutions.
1661     */
1662 #endif
1663 
1664 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
1665 /* Application errors (new in 1.6); use these functions (declared below) for
1666  * errors in the parameters or order of API function calls on read.  The
1667  * 'warning' should be used for an error that can be handled completely; the
1668  * 'error' for one which can be handled safely but which may lose application
1669  * information or settings.
1670  *
1671  * By default these both result in a png_error call prior to release, while in a
1672  * released version the 'warning' is just a warning.  However if the application
1673  * explicitly disables benign errors (explicitly permitting the code to lose
1674  * information) they both turn into warnings.
1675  *
1676  * If benign errors aren't supported they end up as the corresponding base call
1677  * (png_warning or png_error.)
1678  */
1679 PNG_INTERNAL_FUNCTION(void,png_app_warning,(png_const_structrp png_ptr,
1680    png_const_charp message),PNG_EMPTY);
1681    /* The application provided invalid parameters to an API function or called
1682     * an API function at the wrong time, libpng can completely recover.
1683     */
1684 
1685 PNG_INTERNAL_FUNCTION(void,png_app_error,(png_const_structrp png_ptr,
1686    png_const_charp message),PNG_EMPTY);
1687    /* As above but libpng will ignore the call, or attempt some other partial
1688     * recovery from the error.
1689     */
1690 #else
1691 #  define png_app_warning(pp,s) png_warning(pp,s)
1692 #  define png_app_error(pp,s) png_error(pp,s)
1693 #endif
1694 
1695 PNG_INTERNAL_FUNCTION(void,png_chunk_report,(png_const_structrp png_ptr,
1696    png_const_charp message, int error),PNG_EMPTY);
1697    /* Report a recoverable issue in chunk data.  On read this is used to report
1698     * a problem found while reading a particular chunk and the
1699     * png_chunk_benign_error or png_chunk_warning function is used as
1700     * appropriate.  On write this is used to report an error that comes from
1701     * data set via an application call to a png_set_ API and png_app_error or
1702     * png_app_warning is used as appropriate.
1703     *
1704     * The 'error' parameter must have one of the following values:
1705     */
1706 #define PNG_CHUNK_WARNING     0 /* never an error */
1707 #define PNG_CHUNK_WRITE_ERROR 1 /* an error only on write */
1708 #define PNG_CHUNK_ERROR       2 /* always an error */
1709 
1710 /* ASCII to FP interfaces, currently only implemented if sCAL
1711  * support is required.
1712  */
1713 #if defined(PNG_sCAL_SUPPORTED)
1714 /* MAX_DIGITS is actually the maximum number of characters in an sCAL
1715  * width or height, derived from the precision (number of significant
1716  * digits - a build time settable option) and assumptions about the
1717  * maximum ridiculous exponent.
1718  */
1719 #define PNG_sCAL_MAX_DIGITS (PNG_sCAL_PRECISION+1/*.*/+1/*E*/+10/*exponent*/)
1720 
1721 #ifdef PNG_FLOATING_POINT_SUPPORTED
1722 PNG_INTERNAL_FUNCTION(void,png_ascii_from_fp,(png_const_structrp png_ptr,
1723    png_charp ascii, png_size_t size, double fp, unsigned int precision),
1724    PNG_EMPTY);
1725 #endif /* FLOATING_POINT */
1726 
1727 #ifdef PNG_FIXED_POINT_SUPPORTED
1728 PNG_INTERNAL_FUNCTION(void,png_ascii_from_fixed,(png_const_structrp png_ptr,
1729    png_charp ascii, png_size_t size, png_fixed_point fp),PNG_EMPTY);
1730 #endif /* FIXED_POINT */
1731 #endif /* sCAL */
1732 
1733 #if defined(PNG_sCAL_SUPPORTED) || defined(PNG_pCAL_SUPPORTED)
1734 /* An internal API to validate the format of a floating point number.
1735  * The result is the index of the next character.  If the number is
1736  * not valid it will be the index of a character in the supposed number.
1737  *
1738  * The format of a number is defined in the PNG extensions specification
1739  * and this API is strictly conformant to that spec, not anyone elses!
1740  *
1741  * The format as a regular expression is:
1742  *
1743  * [+-]?[0-9]+.?([Ee][+-]?[0-9]+)?
1744  *
1745  * or:
1746  *
1747  * [+-]?.[0-9]+(.[0-9]+)?([Ee][+-]?[0-9]+)?
1748  *
1749  * The complexity is that either integer or fraction must be present and the
1750  * fraction is permitted to have no digits only if the integer is present.
1751  *
1752  * NOTE: The dangling E problem.
1753  *   There is a PNG valid floating point number in the following:
1754  *
1755  *       PNG floating point numbers are not greedy.
1756  *
1757  *   Working this out requires *TWO* character lookahead (because of the
1758  *   sign), the parser does not do this - it will fail at the 'r' - this
1759  *   doesn't matter for PNG sCAL chunk values, but it requires more care
1760  *   if the value were ever to be embedded in something more complex.  Use
1761  *   ANSI-C strtod if you need the lookahead.
1762  */
1763 /* State table for the parser. */
1764 #define PNG_FP_INTEGER    0  /* before or in integer */
1765 #define PNG_FP_FRACTION   1  /* before or in fraction */
1766 #define PNG_FP_EXPONENT   2  /* before or in exponent */
1767 #define PNG_FP_STATE      3  /* mask for the above */
1768 #define PNG_FP_SAW_SIGN   4  /* Saw +/- in current state */
1769 #define PNG_FP_SAW_DIGIT  8  /* Saw a digit in current state */
1770 #define PNG_FP_SAW_DOT   16  /* Saw a dot in current state */
1771 #define PNG_FP_SAW_E     32  /* Saw an E (or e) in current state */
1772 #define PNG_FP_SAW_ANY   60  /* Saw any of the above 4 */
1773 
1774 /* These three values don't affect the parser.  They are set but not used.
1775  */
1776 #define PNG_FP_WAS_VALID 64  /* Preceding substring is a valid fp number */
1777 #define PNG_FP_NEGATIVE 128  /* A negative number, including "-0" */
1778 #define PNG_FP_NONZERO  256  /* A non-zero value */
1779 #define PNG_FP_STICKY   448  /* The above three flags */
1780 
1781 /* This is available for the caller to store in 'state' if required.  Do not
1782  * call the parser after setting it (the parser sometimes clears it.)
1783  */
1784 #define PNG_FP_INVALID  512  /* Available for callers as a distinct value */
1785 
1786 /* Result codes for the parser (boolean - true meants ok, false means
1787  * not ok yet.)
1788  */
1789 #define PNG_FP_MAYBE      0  /* The number may be valid in the future */
1790 #define PNG_FP_OK         1  /* The number is valid */
1791 
1792 /* Tests on the sticky non-zero and negative flags.  To pass these checks
1793  * the state must also indicate that the whole number is valid - this is
1794  * achieved by testing PNG_FP_SAW_DIGIT (see the implementation for why this
1795  * is equivalent to PNG_FP_OK above.)
1796  */
1797 #define PNG_FP_NZ_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NEGATIVE | PNG_FP_NONZERO)
1798    /* NZ_MASK: the string is valid and a non-zero negative value */
1799 #define PNG_FP_Z_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NONZERO)
1800    /* Z MASK: the string is valid and a non-zero value. */
1801    /* PNG_FP_SAW_DIGIT: the string is valid. */
1802 #define PNG_FP_IS_ZERO(state) (((state) & PNG_FP_Z_MASK) == PNG_FP_SAW_DIGIT)
1803 #define PNG_FP_IS_POSITIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_Z_MASK)
1804 #define PNG_FP_IS_NEGATIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_NZ_MASK)
1805 
1806 /* The actual parser.  This can be called repeatedly. It updates
1807  * the index into the string and the state variable (which must
1808  * be initialized to 0).  It returns a result code, as above.  There
1809  * is no point calling the parser any more if it fails to advance to
1810  * the end of the string - it is stuck on an invalid character (or
1811  * terminated by '\0').
1812  *
1813  * Note that the pointer will consume an E or even an E+ and then leave
1814  * a 'maybe' state even though a preceding integer.fraction is valid.
1815  * The PNG_FP_WAS_VALID flag indicates that a preceding substring was
1816  * a valid number.  It's possible to recover from this by calling
1817  * the parser again (from the start, with state 0) but with a string
1818  * that omits the last character (i.e. set the size to the index of
1819  * the problem character.)  This has not been tested within libpng.
1820  */
1821 PNG_INTERNAL_FUNCTION(int,png_check_fp_number,(png_const_charp string,
1822    png_size_t size, int *statep, png_size_tp whereami),PNG_EMPTY);
1823 
1824 /* This is the same but it checks a complete string and returns true
1825  * only if it just contains a floating point number.  As of 1.5.4 this
1826  * function also returns the state at the end of parsing the number if
1827  * it was valid (otherwise it returns 0.)  This can be used for testing
1828  * for negative or zero values using the sticky flag.
1829  */
1830 PNG_INTERNAL_FUNCTION(int,png_check_fp_string,(png_const_charp string,
1831    png_size_t size),PNG_EMPTY);
1832 #endif /* pCAL || sCAL */
1833 
1834 #if defined(PNG_GAMMA_SUPPORTED) ||\
1835     defined(PNG_INCH_CONVERSIONS_SUPPORTED) || defined(PNG_READ_pHYs_SUPPORTED)
1836 /* Added at libpng version 1.5.0 */
1837 /* This is a utility to provide a*times/div (rounded) and indicate
1838  * if there is an overflow.  The result is a boolean - false (0)
1839  * for overflow, true (1) if no overflow, in which case *res
1840  * holds the result.
1841  */
1842 PNG_INTERNAL_FUNCTION(int,png_muldiv,(png_fixed_point_p res, png_fixed_point a,
1843    png_int_32 multiplied_by, png_int_32 divided_by),PNG_EMPTY);
1844 #endif
1845 
1846 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_INCH_CONVERSIONS_SUPPORTED)
1847 /* Same deal, but issue a warning on overflow and return 0. */
1848 PNG_INTERNAL_FUNCTION(png_fixed_point,png_muldiv_warn,
1849    (png_const_structrp png_ptr, png_fixed_point a, png_int_32 multiplied_by,
1850    png_int_32 divided_by),PNG_EMPTY);
1851 #endif
1852 
1853 #ifdef PNG_GAMMA_SUPPORTED
1854 /* Calculate a reciprocal - used for gamma values.  This returns
1855  * 0 if the argument is 0 in order to maintain an undefined value;
1856  * there are no warnings.
1857  */
1858 PNG_INTERNAL_FUNCTION(png_fixed_point,png_reciprocal,(png_fixed_point a),
1859    PNG_EMPTY);
1860 
1861 #ifdef PNG_READ_GAMMA_SUPPORTED
1862 /* The same but gives a reciprocal of the product of two fixed point
1863  * values.  Accuracy is suitable for gamma calculations but this is
1864  * not exact - use png_muldiv for that.  Only required at present on read.
1865  */
1866 PNG_INTERNAL_FUNCTION(png_fixed_point,png_reciprocal2,(png_fixed_point a,
1867    png_fixed_point b),PNG_EMPTY);
1868 #endif
1869 
1870 /* Return true if the gamma value is significantly different from 1.0 */
1871 PNG_INTERNAL_FUNCTION(int,png_gamma_significant,(png_fixed_point gamma_value),
1872    PNG_EMPTY);
1873 #endif
1874 
1875 #ifdef PNG_READ_GAMMA_SUPPORTED
1876 /* Internal fixed point gamma correction.  These APIs are called as
1877  * required to convert single values - they don't need to be fast,
1878  * they are not used when processing image pixel values.
1879  *
1880  * While the input is an 'unsigned' value it must actually be the
1881  * correct bit value - 0..255 or 0..65535 as required.
1882  */
1883 PNG_INTERNAL_FUNCTION(png_uint_16,png_gamma_correct,(png_structrp png_ptr,
1884    unsigned int value, png_fixed_point gamma_value),PNG_EMPTY);
1885 PNG_INTERNAL_FUNCTION(png_uint_16,png_gamma_16bit_correct,(unsigned int value,
1886    png_fixed_point gamma_value),PNG_EMPTY);
1887 PNG_INTERNAL_FUNCTION(png_byte,png_gamma_8bit_correct,(unsigned int value,
1888    png_fixed_point gamma_value),PNG_EMPTY);
1889 PNG_INTERNAL_FUNCTION(void,png_destroy_gamma_table,(png_structrp png_ptr),
1890    PNG_EMPTY);
1891 PNG_INTERNAL_FUNCTION(void,png_build_gamma_table,(png_structrp png_ptr,
1892    int bit_depth),PNG_EMPTY);
1893 #endif
1894 
1895 /* SIMPLIFIED READ/WRITE SUPPORT */
1896 #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
1897    defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
1898 /* The internal structure that png_image::opaque points to. */
1899 typedef struct png_control
1900 {
1901    png_structp png_ptr;
1902    png_infop   info_ptr;
1903    png_voidp   error_buf;           /* Always a jmp_buf at present. */
1904 
1905    png_const_bytep memory;          /* Memory buffer. */
1906    png_size_t      size;            /* Size of the memory buffer. */
1907 
1908    unsigned int for_write       :1; /* Otherwise it is a read structure */
1909    unsigned int owned_file      :1; /* We own the file in io_ptr */
1910 } png_control;
1911 
1912 /* Return the pointer to the jmp_buf from a png_control: necessary because C
1913  * does not reveal the type of the elements of jmp_buf.
1914  */
1915 #ifdef __cplusplus
1916 #  define png_control_jmp_buf(pc) (((jmp_buf*)((pc)->error_buf))[0])
1917 #else
1918 #  define png_control_jmp_buf(pc) ((pc)->error_buf)
1919 #endif
1920 
1921 /* Utility to safely execute a piece of libpng code catching and logging any
1922  * errors that might occur.  Returns true on success, false on failure (either
1923  * of the function or as a result of a png_error.)
1924  */
1925 PNG_INTERNAL_CALLBACK(void,png_safe_error,(png_structp png_ptr,
1926    png_const_charp error_message),PNG_NORETURN);
1927 
1928 #ifdef PNG_WARNINGS_SUPPORTED
1929 PNG_INTERNAL_CALLBACK(void,png_safe_warning,(png_structp png_ptr,
1930    png_const_charp warning_message),PNG_EMPTY);
1931 #else
1932 #  define png_safe_warning 0/*dummy argument*/
1933 #endif
1934 
1935 PNG_INTERNAL_FUNCTION(int,png_safe_execute,(png_imagep image,
1936    int (*function)(png_voidp), png_voidp arg),PNG_EMPTY);
1937 
1938 /* Utility to log an error; this also cleans up the png_image; the function
1939  * always returns 0 (false).
1940  */
1941 PNG_INTERNAL_FUNCTION(int,png_image_error,(png_imagep image,
1942    png_const_charp error_message),PNG_EMPTY);
1943 
1944 #ifndef PNG_SIMPLIFIED_READ_SUPPORTED
1945 /* png_image_free is used by the write code but not exported */
1946 PNG_INTERNAL_FUNCTION(void, png_image_free, (png_imagep image), PNG_EMPTY);
1947 #endif /* !SIMPLIFIED_READ */
1948 
1949 #endif /* SIMPLIFIED READ/WRITE */
1950 
1951 /* These are initialization functions for hardware specific PNG filter
1952  * optimizations; list these here then select the appropriate one at compile
1953  * time using the macro PNG_FILTER_OPTIMIZATIONS.  If the macro is not defined
1954  * the generic code is used.
1955  */
1956 #ifdef PNG_FILTER_OPTIMIZATIONS
1957 PNG_INTERNAL_FUNCTION(void, PNG_FILTER_OPTIMIZATIONS, (png_structp png_ptr,
1958    unsigned int bpp), PNG_EMPTY);
1959    /* Just declare the optimization that will be used */
1960 #else
1961    /* List *all* the possible optimizations here - this branch is required if
1962     * the builder of libpng passes the definition of PNG_FILTER_OPTIMIZATIONS in
1963     * CFLAGS in place of CPPFLAGS *and* uses symbol prefixing.
1964     */
1965 PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_neon,
1966    (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
1967 PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_sse2,
1968    (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
1969 #endif
1970 
1971 PNG_INTERNAL_FUNCTION(png_uint_32, png_check_keyword, (png_structrp png_ptr,
1972    png_const_charp key, png_bytep new_key), PNG_EMPTY);
1973 
1974 /* Maintainer: Put new private prototypes here ^ */
1975 
1976 #include "pngdebug.h"
1977 
1978 #ifdef __cplusplus
1979 }
1980 #endif
1981 
1982 #endif /* PNG_VERSION_INFO_ONLY */
1983 #endif /* PNGPRIV_H */
1984