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pngpriv.h
1 
2 /* pngpriv.h - private declarations for use inside libpng
3  *
4  * For conditions of distribution and use, see copyright notice in png.h
5  * Copyright (c) 1998-2014 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  * Last changed in libpng 1.6.10 [March 6, 1014]]
10  *
11  * This code is released under the libpng license.
12  * For conditions of distribution and use, see the disclaimer
13  * and license in png.h
14  */
15 
16 /* The symbols declared in this file (including the functions declared
17  * as extern) are PRIVATE. They are not part of the libpng public
18  * interface, and are not recommended for use by regular applications.
19  * Some of them may become public in the future; others may stay private,
20  * change in an incompatible way, or even disappear.
21  * Although the libpng users are not forbidden to include this header,
22  * they should be well aware of the issues that may arise from doing so.
23  */
24 
25 #ifndef PNGPRIV_H
26 #define PNGPRIV_H
27 
28 /* Feature Test Macros. The following are defined here to ensure that correctly
29  * implemented libraries reveal the APIs libpng needs to build and hide those
30  * that are not needed and potentially damaging to the compilation.
31  *
32  * Feature Test Macros must be defined before any system header is included (see
33  * POSIX 1003.1 2.8.2 "POSIX Symbols."
34  *
35  * These macros only have an effect if the operating system supports either
36  * POSIX 1003.1 or C99, or both. On other operating systems (particularly
37  * Windows/Visual Studio) there is no effect; the OS specific tests below are
38  * still required (as of 2011-05-02.)
39  */
40 #define _POSIX_SOURCE 1 /* Just the POSIX 1003.1 and C89 APIs */
41 
42 #ifndef PNG_VERSION_INFO_ONLY
43 /* Standard library headers not required by png.h: */
44 # include <stdlib.h>
45 # include <string.h>
46 #endif
47 
48 #define PNGLIB_BUILD /*libpng is being built, not used*/
49 
50 /* If HAVE_CONFIG_H is defined during the build then the build system must
51  * provide an appropriate "config.h" file on the include path. The header file
52  * must provide definitions as required below (search for "HAVE_CONFIG_H");
53  * see configure.ac for more details of the requirements. The macro
54  * "PNG_NO_CONFIG_H" is provided for maintainers to test for dependencies on
55  * 'configure'; define this macro to prevent the configure build including the
56  * configure generated config.h. Libpng is expected to compile without *any*
57  * special build system support on a reasonably ANSI-C compliant system.
58  */
59 #if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
60 # include <config.h>
61 
62  /* Pick up the definition of 'restrict' from config.h if it was read: */
63 # define PNG_RESTRICT restrict
64 #endif
65 
66 /* To support symbol prefixing it is necessary to know *before* including png.h
67  * whether the fixed point (and maybe other) APIs are exported, because if they
68  * are not internal definitions may be required. This is handled below just
69  * before png.h is included, but load the configuration now if it is available.
70  */
71 #ifndef PNGLCONF_H
72 # include "pnglibconf.h"
73 #endif
74 
75 /* Local renames may change non-exported API functions from png.h */
76 #if defined(PNG_PREFIX) && !defined(PNGPREFIX_H)
77 # include "pngprefix.h"
78 #endif
79 
80 #ifdef PNG_USER_CONFIG
81 # include "pngusr.h"
82  /* These should have been defined in pngusr.h */
83 # ifndef PNG_USER_PRIVATEBUILD
84 # define PNG_USER_PRIVATEBUILD "Custom libpng build"
85 # endif
86 # ifndef PNG_USER_DLLFNAME_POSTFIX
87 # define PNG_USER_DLLFNAME_POSTFIX "Cb"
88 # endif
89 #endif
90 
91 /* Compile time options.
92  * =====================
93  * In a multi-arch build the compiler may compile the code several times for the
94  * same object module, producing different binaries for different architectures.
95  * When this happens configure-time setting of the target host options cannot be
96  * done and this interferes with the handling of the ARM NEON optimizations, and
97  * possibly other similar optimizations. Put additional tests here; in general
98  * this is needed when the same option can be changed at both compile time and
99  * run time depending on the target OS (i.e. iOS vs Android.)
100  *
101  * NOTE: symbol prefixing does not pass $(CFLAGS) to the preprocessor, because
102  * this is not possible with certain compilers (Oracle SUN OS CC), as a result
103  * it is necessary to ensure that all extern functions that *might* be used
104  * regardless of $(CFLAGS) get declared in this file. The test on __ARM_NEON__
105  * below is one example of this behavior because it is controlled by the
106  * presence or not of -mfpu=neon on the GCC command line, it is possible to do
107  * this in $(CC), e.g. "CC=gcc -mfpu=neon", but people who build libpng rarely
108  * do this.
109  */
110 #ifndef PNG_ARM_NEON_OPT
111  /* ARM NEON optimizations are being controlled by the compiler settings,
112  * typically the target FPU. If the FPU has been set to NEON (-mfpu=neon
113  * with GCC) then the compiler will define __ARM_NEON__ and we can rely
114  * unconditionally on NEON instructions not crashing, otherwise we must
115  * disable use of NEON instructions.
116  *
117  * NOTE: at present these optimizations depend on 'ALIGNED_MEMORY', so they
118  * can only be turned on automatically if that is supported too. If
119  * PNG_ARM_NEON_OPT is set in CPPFLAGS (to >0) then arm/arm_init.c will fail
120  * to compile with an appropriate #error if ALIGNED_MEMORY has been turned
121  * off.
122  *
123  * Note that gcc-4.9 defines __ARM_NEON instead of __ARM_NEON__, so we
124  * check both variants.
125  */
126 # if (defined(__ARM_NEON__) || defined(__ARM_NEON)) && \
127  defined(PNG_ALIGNED_MEMORY_SUPPORTED)
128 # define PNG_ARM_NEON_OPT 2
129 # else
130 # define PNG_ARM_NEON_OPT 0
131 # endif
132 #endif
133 
134 #if PNG_ARM_NEON_OPT > 0
135  /* NEON optimizations are to be at least considered by libpng, so enable the
136  * callbacks to do this.
137  */
138 # define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_neon
139 
140  /* By default the 'intrinsics' code in arm/filter_neon_intrinsics.c is used
141  * if possible - if __ARM_NEON__ is set and the compiler version is not known
142  * to be broken. This is controlled by PNG_ARM_NEON_IMPLEMENTATION which can
143  * be:
144  *
145  * 1 The intrinsics code (the default with __ARM_NEON__)
146  * 2 The hand coded assembler (the default without __ARM_NEON__)
147  *
148  * It is possible to set PNG_ARM_NEON_IMPLEMENTATION in CPPFLAGS, however
149  * this is *NOT* supported and may cease to work even after a minor revision
150  * to libpng. It *is* valid to do this for testing purposes, e.g. speed
151  * testing or a new compiler, but the results should be communicated to the
152  * libpng implementation list for incorporation in the next minor release.
153  */
154 # ifndef PNG_ARM_NEON_IMPLEMENTATION
155 # if defined(__ARM_NEON__) || defined(__ARM_NEON)
156 # if defined(__clang__)
157  /* At present it is unknown by the libpng developers which versions
158  * of clang support the intrinsics, however some or perhaps all
159  * versions do not work with the assembler so this may be
160  * irrelevant, so just use the default (do nothing here.)
161  */
162 # elif defined(__GNUC__)
163  /* GCC 4.5.4 NEON support is known to be broken. 4.6.3 is known to
164  * work, so if this *is* GCC, or G++, look for a version >4.5
165  */
166 # if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 6)
167 # define PNG_ARM_NEON_IMPLEMENTATION 2
168 # endif /* no GNUC support */
169 # endif /* __GNUC__ */
170 # else /* !defined __ARM_NEON__ */
171  /* The 'intrinsics' code simply won't compile without this -mfpu=neon:
172  */
173 # define PNG_ARM_NEON_IMPLEMENTATION 2
174 # endif /* __ARM_NEON__ */
175 # endif /* !PNG_ARM_NEON_IMPLEMENTATION */
176 
177 # ifndef PNG_ARM_NEON_IMPLEMENTATION
178  /* Use the intrinsics code by default. */
179 # define PNG_ARM_NEON_IMPLEMENTATION 1
180 # endif
181 #endif /* PNG_ARM_NEON_OPT > 0 */
182 
183 /* Is this a build of a DLL where compilation of the object modules requires
184  * different preprocessor settings to those required for a simple library? If
185  * so PNG_BUILD_DLL must be set.
186  *
187  * If libpng is used inside a DLL but that DLL does not export the libpng APIs
188  * PNG_BUILD_DLL must not be set. To avoid the code below kicking in build a
189  * static library of libpng then link the DLL against that.
190  */
191 #ifndef PNG_BUILD_DLL
192 # ifdef DLL_EXPORT
193  /* This is set by libtool when files are compiled for a DLL; libtool
194  * always compiles twice, even on systems where it isn't necessary. Set
195  * PNG_BUILD_DLL in case it is necessary:
196  */
197 # define PNG_BUILD_DLL
198 # else
199 # ifdef _WINDLL
200  /* This is set by the Microsoft Visual Studio IDE in projects that
201  * build a DLL. It can't easily be removed from those projects (it
202  * isn't visible in the Visual Studio UI) so it is a fairly reliable
203  * indication that PNG_IMPEXP needs to be set to the DLL export
204  * attributes.
205  */
206 # define PNG_BUILD_DLL
207 # else
208 # ifdef __DLL__
209  /* This is set by the Borland C system when compiling for a DLL
210  * (as above.)
211  */
212 # define PNG_BUILD_DLL
213 # else
214  /* Add additional compiler cases here. */
215 # endif
216 # endif
217 # endif
218 #endif /* Setting PNG_BUILD_DLL if required */
219 
220 /* See pngconf.h for more details: the builder of the library may set this on
221  * the command line to the right thing for the specific compilation system or it
222  * may be automagically set above (at present we know of no system where it does
223  * need to be set on the command line.)
224  *
225  * PNG_IMPEXP must be set here when building the library to prevent pngconf.h
226  * setting it to the "import" setting for a DLL build.
227  */
228 #ifndef PNG_IMPEXP
229 # ifdef PNG_BUILD_DLL
230 # define PNG_IMPEXP PNG_DLL_EXPORT
231 # else
232  /* Not building a DLL, or the DLL doesn't require specific export
233  * definitions.
234  */
235 # define PNG_IMPEXP
236 # endif
237 #endif
238 
239 /* No warnings for private or deprecated functions in the build: */
240 #ifndef PNG_DEPRECATED
241 # define PNG_DEPRECATED
242 #endif
243 #ifndef PNG_PRIVATE
244 # define PNG_PRIVATE
245 #endif
246 
247 /* Symbol preprocessing support.
248  *
249  * To enable listing global, but internal, symbols the following macros should
250  * always be used to declare an extern data or function object in this file.
251  */
252 #ifndef PNG_INTERNAL_DATA
253 # define PNG_INTERNAL_DATA(type, name, array) extern type name array
254 #endif
255 
256 #ifndef PNG_INTERNAL_FUNCTION
257 # define PNG_INTERNAL_FUNCTION(type, name, args, attributes)\
258  extern PNG_FUNCTION(type, name, args, PNG_EMPTY attributes)
259 #endif
260 
261 #ifndef PNG_INTERNAL_CALLBACK
262 # define PNG_INTERNAL_CALLBACK(type, name, args, attributes)\
263  extern PNG_FUNCTION(type, (PNGCBAPI name), args, PNG_EMPTY attributes)
264 #endif
265 
266 /* If floating or fixed point APIs are disabled they may still be compiled
267  * internally. To handle this make sure they are declared as the appropriate
268  * internal extern function (otherwise the symbol prefixing stuff won't work and
269  * the functions will be used without definitions.)
270  *
271  * NOTE: although all the API functions are declared here they are not all
272  * actually built! Because the declarations are still made it is necessary to
273  * fake out types that they depend on.
274  */
275 #ifndef PNG_FP_EXPORT
276 # ifndef PNG_FLOATING_POINT_SUPPORTED
277 # define PNG_FP_EXPORT(ordinal, type, name, args)\
278  PNG_INTERNAL_FUNCTION(type, name, args, PNG_EMPTY);
279 # ifndef PNG_VERSION_INFO_ONLY
280  typedef struct png_incomplete png_double;
281  typedef png_double* png_doublep;
282  typedef const png_double* png_const_doublep;
283  typedef png_double** png_doublepp;
284 # endif
285 # endif
286 #endif
287 #ifndef PNG_FIXED_EXPORT
288 # ifndef PNG_FIXED_POINT_SUPPORTED
289 # define PNG_FIXED_EXPORT(ordinal, type, name, args)\
290  PNG_INTERNAL_FUNCTION(type, name, args, PNG_EMPTY);
291 # endif
292 #endif
293 
294 #include "png.h"
295 
296 /* pngconf.h does not set PNG_DLL_EXPORT unless it is required, so: */
297 #ifndef PNG_DLL_EXPORT
298 # define PNG_DLL_EXPORT
299 #endif
300 
301 /* SECURITY and SAFETY:
302  *
303  * By default libpng is built without any internal limits on image size,
304  * individual heap (png_malloc) allocations or the total amount of memory used.
305  * If PNG_SAFE_LIMITS_SUPPORTED is defined, however, the limits below are used
306  * (unless individually overridden). These limits are believed to be fairly
307  * safe, but builders of secure systems should verify the values against the
308  * real system capabilities.
309  */
310 #ifdef PNG_SAFE_LIMITS_SUPPORTED
311  /* 'safe' limits */
312 # ifndef PNG_USER_WIDTH_MAX
313 # define PNG_USER_WIDTH_MAX 1000000
314 # endif
315 # ifndef PNG_USER_HEIGHT_MAX
316 # define PNG_USER_HEIGHT_MAX 1000000
317 # endif
318 # ifndef PNG_USER_CHUNK_CACHE_MAX
319 # define PNG_USER_CHUNK_CACHE_MAX 128
320 # endif
321 # ifndef PNG_USER_CHUNK_MALLOC_MAX
322 # define PNG_USER_CHUNK_MALLOC_MAX 8000000
323 # endif
324 #else
325  /* values for no limits */
326 # ifndef PNG_USER_WIDTH_MAX
327 # define PNG_USER_WIDTH_MAX 0x7fffffff
328 # endif
329 # ifndef PNG_USER_HEIGHT_MAX
330 # define PNG_USER_HEIGHT_MAX 0x7fffffff
331 # endif
332 # ifndef PNG_USER_CHUNK_CACHE_MAX
333 # define PNG_USER_CHUNK_CACHE_MAX 0
334 # endif
335 # ifndef PNG_USER_CHUNK_MALLOC_MAX
336 # define PNG_USER_CHUNK_MALLOC_MAX 0
337 # endif
338 #endif
339 
340 /* Moved to pngpriv.h at libpng-1.5.0 */
341 /* NOTE: some of these may have been used in external applications as
342  * these definitions were exposed in pngconf.h prior to 1.5.
343  */
344 
345 /* If you are running on a machine where you cannot allocate more
346  * than 64K of memory at once, uncomment this. While libpng will not
347  * normally need that much memory in a chunk (unless you load up a very
348  * large file), zlib needs to know how big of a chunk it can use, and
349  * libpng thus makes sure to check any memory allocation to verify it
350  * will fit into memory.
351  *
352  * zlib provides 'MAXSEG_64K' which, if defined, indicates the
353  * same limit and pngconf.h (already included) sets the limit
354  * if certain operating systems are detected.
355  */
356 #if defined(MAXSEG_64K) && !defined(PNG_MAX_MALLOC_64K)
357 # define PNG_MAX_MALLOC_64K
358 #endif
359 
360 #ifndef PNG_UNUSED
361 /* Unused formal parameter warnings are silenced using the following macro
362  * which is expected to have no bad effects on performance (optimizing
363  * compilers will probably remove it entirely). Note that if you replace
364  * it with something other than whitespace, you must include the terminating
365  * semicolon.
366  */
367 # define PNG_UNUSED(param) (void)param;
368 #endif
369 
370 /* Just a little check that someone hasn't tried to define something
371  * contradictory.
372  */
373 #if (PNG_ZBUF_SIZE > 65536L) && defined(PNG_MAX_MALLOC_64K)
374 # undef PNG_ZBUF_SIZE
375 # define PNG_ZBUF_SIZE 65536L
376 #endif
377 
378 /* If warnings or errors are turned off the code is disabled or redirected here.
379  * From 1.5.4 functions have been added to allow very limited formatting of
380  * error and warning messages - this code will also be disabled here.
381  */
382 #ifdef PNG_WARNINGS_SUPPORTED
383 # define PNG_WARNING_PARAMETERS(p) png_warning_parameters p;
384 #else
385 # define png_warning_parameter(p,number,string) ((void)0)
386 # define png_warning_parameter_unsigned(p,number,format,value) ((void)0)
387 # define png_warning_parameter_signed(p,number,format,value) ((void)0)
388 # define png_formatted_warning(pp,p,message) ((void)(pp))
389 # define PNG_WARNING_PARAMETERS(p)
390 #endif
391 #ifndef PNG_ERROR_TEXT_SUPPORTED
392 # define png_fixed_error(s1,s2) png_err(s1)
393 #endif
394 
395 /* C allows up-casts from (void*) to any pointer and (const void*) to any
396  * pointer to a const object. C++ regards this as a type error and requires an
397  * explicit, static, cast and provides the static_cast<> rune to ensure that
398  * const is not cast away.
399  */
400 #ifdef __cplusplus
401 # define png_voidcast(type, value) static_cast<type>(value)
402 # define png_constcast(type, value) const_cast<type>(value)
403 # define png_aligncast(type, value) \
404  static_cast<type>(static_cast<void*>(value))
405 # define png_aligncastconst(type, value) \
406  static_cast<type>(static_cast<const void*>(value))
407 #else
408 # define png_voidcast(type, value) (value)
409 # define png_constcast(type, value) ((type)(value))
410 # define png_aligncast(type, value) ((void*)(value))
411 # define png_aligncastconst(type, value) ((const void*)(value))
412 #endif /* __cplusplus */
413 
414 /* Some fixed point APIs are still required even if not exported because
415  * they get used by the corresponding floating point APIs. This magic
416  * deals with this:
417  */
418 #ifdef PNG_FIXED_POINT_SUPPORTED
419 # define PNGFAPI PNGAPI
420 #else
421 # define PNGFAPI /* PRIVATE */
422 #endif
423 
424 #ifndef PNG_VERSION_INFO_ONLY
425 /* Other defines specific to compilers can go here. Try to keep
426  * them inside an appropriate ifdef/endif pair for portability.
427  */
428 #if defined(PNG_FLOATING_POINT_SUPPORTED) ||\
429  defined(PNG_FLOATING_ARITHMETIC_SUPPORTED)
430  /* png.c requires the following ANSI-C constants if the conversion of
431  * floating point to ASCII is implemented therein:
432  *
433  * DBL_DIG Maximum number of decimal digits (can be set to any constant)
434  * DBL_MIN Smallest normalized fp number (can be set to an arbitrary value)
435  * DBL_MAX Maximum floating point number (can be set to an arbitrary value)
436  */
437 # include <float.h>
438 
439 # if (defined(__MWERKS__) && defined(macintosh)) || defined(applec) || \
440  defined(THINK_C) || defined(__SC__) || defined(TARGET_OS_MAC)
441  /* We need to check that <math.h> hasn't already been included earlier
442  * as it seems it doesn't agree with <fp.h>, yet we should really use
443  * <fp.h> if possible.
444  */
445 # if !defined(__MATH_H__) && !defined(__MATH_H) && !defined(__cmath__)
446 # include <fp.h>
447 # endif
448 # else
449 # include <math.h>
450 # endif
451 # if defined(_AMIGA) && defined(__SASC) && defined(_M68881)
452  /* Amiga SAS/C: We must include builtin FPU functions when compiling using
453  * MATH=68881
454  */
455 # include <m68881.h>
456 # endif
457 #endif
458 
459 /* This provides the non-ANSI (far) memory allocation routines. */
460 #if defined(__TURBOC__) && defined(__MSDOS__)
461 # include <mem.h>
462 # include <alloc.h>
463 #endif
464 
465 #if defined(WIN32) || defined(_Windows) || defined(_WINDOWS) || \
466  defined(_WIN32) || defined(__WIN32__)
467 # include <windows.h> /* defines _WINDOWS_ macro */
468 #endif
469 #endif /* PNG_VERSION_INFO_ONLY */
470 
471 /* Moved here around 1.5.0beta36 from pngconf.h */
472 /* Users may want to use these so they are not private. Any library
473  * functions that are passed far data must be model-independent.
474  */
475 
476 /* Memory model/platform independent fns */
477 #ifndef PNG_ABORT
478 # ifdef _WINDOWS_
479 # define PNG_ABORT() ExitProcess(0)
480 # else
481 # define PNG_ABORT() abort()
482 # endif
483 #endif
484 
485 /* These macros may need to be architecture dependent. */
486 #define PNG_ALIGN_NONE 0 /* do not use data alignment */
487 #define PNG_ALIGN_ALWAYS 1 /* assume unaligned accesses are OK */
488 #ifdef offsetof
489 # define PNG_ALIGN_OFFSET 2 /* use offsetof to determine alignment */
490 #else
491 # define PNG_ALIGN_OFFSET -1 /* prevent the use of this */
492 #endif
493 #define PNG_ALIGN_SIZE 3 /* use sizeof to determine alignment */
494 
495 #ifndef PNG_ALIGN_TYPE
496  /* Default to using aligned access optimizations and requiring alignment to a
497  * multiple of the data type size. Override in a compiler specific fashion
498  * if necessary by inserting tests here:
499  */
500 # define PNG_ALIGN_TYPE PNG_ALIGN_SIZE
501 #endif
502 
503 #if PNG_ALIGN_TYPE == PNG_ALIGN_SIZE
504  /* This is used because in some compiler implementations non-aligned
505  * structure members are supported, so the offsetof approach below fails.
506  * Set PNG_ALIGN_SIZE=0 for compiler combinations where unaligned access
507  * is good for performance. Do not do this unless you have tested the result
508  * and understand it.
509  */
510 # define png_alignof(type) (sizeof (type))
511 #else
512 # if PNG_ALIGN_TYPE == PNG_ALIGN_OFFSET
513 # define png_alignof(type) offsetof(struct{char c; type t;}, t)
514 # else
515 # if PNG_ALIGN_TYPE == PNG_ALIGN_ALWAYS
516 # define png_alignof(type) (1)
517 # endif
518  /* Else leave png_alignof undefined to prevent use thereof */
519 # endif
520 #endif
521 
522 /* This implicitly assumes alignment is always to a power of 2. */
523 #ifdef png_alignof
524 # define png_isaligned(ptr, type)\
525  ((((const char*)ptr-(const char*)0) & (png_alignof(type)-1)) == 0)
526 #else
527 # define png_isaligned(ptr, type) 0
528 #endif
529 
530 /* End of memory model/platform independent support */
531 /* End of 1.5.0beta36 move from pngconf.h */
532 
533 /* CONSTANTS and UTILITY MACROS
534  * These are used internally by libpng and not exposed in the API
535  */
536 
537 /* Various modes of operation. Note that after an init, mode is set to
538  * zero automatically when the structure is created. Three of these
539  * are defined in png.h because they need to be visible to applications
540  * that call png_set_unknown_chunk().
541  */
542 /* #define PNG_HAVE_IHDR 0x01 (defined in png.h) */
543 /* #define PNG_HAVE_PLTE 0x02 (defined in png.h) */
544 #define PNG_HAVE_IDAT 0x04
545 /* #define PNG_AFTER_IDAT 0x08 (defined in png.h) */
546 #define PNG_HAVE_IEND 0x10
547  /* 0x20 (unused) */
548  /* 0x40 (unused) */
549  /* 0x80 (unused) */
550 #define PNG_HAVE_CHUNK_HEADER 0x100
551 #define PNG_WROTE_tIME 0x200
552 #define PNG_WROTE_INFO_BEFORE_PLTE 0x400
553 #define PNG_BACKGROUND_IS_GRAY 0x800
554 #define PNG_HAVE_PNG_SIGNATURE 0x1000
555 #define PNG_HAVE_CHUNK_AFTER_IDAT 0x2000 /* Have another chunk after IDAT */
556  /* 0x4000 (unused) */
557 #define PNG_IS_READ_STRUCT 0x8000 /* Else is a write struct */
558 
559 /* Flags for the transformations the PNG library does on the image data */
560 #define PNG_BGR 0x0001
561 #define PNG_INTERLACE 0x0002
562 #define PNG_PACK 0x0004
563 #define PNG_SHIFT 0x0008
564 #define PNG_SWAP_BYTES 0x0010
565 #define PNG_INVERT_MONO 0x0020
566 #define PNG_QUANTIZE 0x0040
567 #define PNG_COMPOSE 0x0080 /* Was PNG_BACKGROUND */
568 #define PNG_BACKGROUND_EXPAND 0x0100
569 #define PNG_EXPAND_16 0x0200 /* Added to libpng 1.5.2 */
570 #define PNG_16_TO_8 0x0400 /* Becomes 'chop' in 1.5.4 */
571 #define PNG_RGBA 0x0800
572 #define PNG_EXPAND 0x1000
573 #define PNG_GAMMA 0x2000
574 #define PNG_GRAY_TO_RGB 0x4000
575 #define PNG_FILLER 0x8000
576 #define PNG_PACKSWAP 0x10000
577 #define PNG_SWAP_ALPHA 0x20000
578 #define PNG_STRIP_ALPHA 0x40000
579 #define PNG_INVERT_ALPHA 0x80000
580 #define PNG_USER_TRANSFORM 0x100000
581 #define PNG_RGB_TO_GRAY_ERR 0x200000
582 #define PNG_RGB_TO_GRAY_WARN 0x400000
583 #define PNG_RGB_TO_GRAY 0x600000 /* two bits, RGB_TO_GRAY_ERR|WARN */
584 #define PNG_ENCODE_ALPHA 0x800000 /* Added to libpng-1.5.4 */
585 #define PNG_ADD_ALPHA 0x1000000 /* Added to libpng-1.2.7 */
586 #define PNG_EXPAND_tRNS 0x2000000 /* Added to libpng-1.2.9 */
587 #define PNG_SCALE_16_TO_8 0x4000000 /* Added to libpng-1.5.4 */
588  /* 0x8000000 unused */
589  /* 0x10000000 unused */
590  /* 0x20000000 unused */
591  /* 0x40000000 unused */
592 /* Flags for png_create_struct */
593 #define PNG_STRUCT_PNG 0x0001
594 #define PNG_STRUCT_INFO 0x0002
595 
596 /* Scaling factor for filter heuristic weighting calculations */
597 #define PNG_WEIGHT_FACTOR (1<<(PNG_WEIGHT_SHIFT))
598 #define PNG_COST_FACTOR (1<<(PNG_COST_SHIFT))
599 
600 /* Flags for the png_ptr->flags rather than declaring a byte for each one */
601 #define PNG_FLAG_ZLIB_CUSTOM_STRATEGY 0x0001
602 #define PNG_FLAG_ZSTREAM_INITIALIZED 0x0002 /* Added to libpng-1.6.0 */
603  /* 0x0004 unused */
604 #define PNG_FLAG_ZSTREAM_ENDED 0x0008 /* Added to libpng-1.6.0 */
605  /* 0x0010 unused */
606  /* 0x0020 unused */
607 #define PNG_FLAG_ROW_INIT 0x0040
608 #define PNG_FLAG_FILLER_AFTER 0x0080
609 #define PNG_FLAG_CRC_ANCILLARY_USE 0x0100
610 #define PNG_FLAG_CRC_ANCILLARY_NOWARN 0x0200
611 #define PNG_FLAG_CRC_CRITICAL_USE 0x0400
612 #define PNG_FLAG_CRC_CRITICAL_IGNORE 0x0800
613 #define PNG_FLAG_ASSUME_sRGB 0x1000 /* Added to libpng-1.5.4 */
614 #define PNG_FLAG_OPTIMIZE_ALPHA 0x2000 /* Added to libpng-1.5.4 */
615 #define PNG_FLAG_DETECT_UNINITIALIZED 0x4000 /* Added to libpng-1.5.4 */
616 /* #define PNG_FLAG_KEEP_UNKNOWN_CHUNKS 0x8000 */
617 /* #define PNG_FLAG_KEEP_UNSAFE_CHUNKS 0x10000 */
618 #define PNG_FLAG_LIBRARY_MISMATCH 0x20000
619 #define PNG_FLAG_STRIP_ERROR_NUMBERS 0x40000
620 #define PNG_FLAG_STRIP_ERROR_TEXT 0x80000
621 #define PNG_FLAG_BENIGN_ERRORS_WARN 0x100000 /* Added to libpng-1.4.0 */
622 #define PNG_FLAG_APP_WARNINGS_WARN 0x200000 /* Added to libpng-1.6.0 */
623 #define PNG_FLAG_APP_ERRORS_WARN 0x400000 /* Added to libpng-1.6.0 */
624  /* 0x800000 unused */
625  /* 0x1000000 unused */
626  /* 0x2000000 unused */
627  /* 0x4000000 unused */
628  /* 0x8000000 unused */
629  /* 0x10000000 unused */
630  /* 0x20000000 unused */
631  /* 0x40000000 unused */
632 
633 #define PNG_FLAG_CRC_ANCILLARY_MASK (PNG_FLAG_CRC_ANCILLARY_USE | \
634  PNG_FLAG_CRC_ANCILLARY_NOWARN)
635 
636 #define PNG_FLAG_CRC_CRITICAL_MASK (PNG_FLAG_CRC_CRITICAL_USE | \
637  PNG_FLAG_CRC_CRITICAL_IGNORE)
638 
639 #define PNG_FLAG_CRC_MASK (PNG_FLAG_CRC_ANCILLARY_MASK | \
640  PNG_FLAG_CRC_CRITICAL_MASK)
641 
642 /* Save typing and make code easier to understand */
643 
644 #define PNG_COLOR_DIST(c1, c2) (abs((int)((c1).red) - (int)((c2).red)) + \
645  abs((int)((c1).green) - (int)((c2).green)) + \
646  abs((int)((c1).blue) - (int)((c2).blue)))
647 
648 /* Added to libpng-1.6.0: scale a 16-bit value in the range 0..65535 to 0..255
649  * by dividing by 257 *with rounding*. This macro is exact for the given range.
650  * See the discourse in pngrtran.c png_do_scale_16_to_8. The values in the
651  * macro were established by experiment (modifying the added value). The macro
652  * has a second variant that takes a value already scaled by 255 and divides by
653  * 65535 - this has a maximum error of .502. Over the range 0..65535*65535 it
654  * only gives off-by-one errors and only for 0.5% (1 in 200) of the values.
655  */
656 #define PNG_DIV65535(v24) (((v24) + 32895) >> 16)
657 #define PNG_DIV257(v16) PNG_DIV65535((png_uint_32)(v16) * 255)
658 
659 /* Added to libpng-1.2.6 JB */
660 #define PNG_ROWBYTES(pixel_bits, width) \
661  ((pixel_bits) >= 8 ? \
662  ((png_size_t)(width) * (((png_size_t)(pixel_bits)) >> 3)) : \
663  (( ((png_size_t)(width) * ((png_size_t)(pixel_bits))) + 7) >> 3) )
664 
665 /* PNG_OUT_OF_RANGE returns true if value is outside the range
666  * ideal-delta..ideal+delta. Each argument is evaluated twice.
667  * "ideal" and "delta" should be constants, normally simple
668  * integers, "value" a variable. Added to libpng-1.2.6 JB
669  */
670 #define PNG_OUT_OF_RANGE(value, ideal, delta) \
671  ( (value) < (ideal)-(delta) || (value) > (ideal)+(delta) )
672 
673 /* Conversions between fixed and floating point, only defined if
674  * required (to make sure the code doesn't accidentally use float
675  * when it is supposedly disabled.)
676  */
677 #ifdef PNG_FLOATING_POINT_SUPPORTED
678 /* The floating point conversion can't overflow, though it can and
679  * does lose accuracy relative to the original fixed point value.
680  * In practice this doesn't matter because png_fixed_point only
681  * stores numbers with very low precision. The png_ptr and s
682  * arguments are unused by default but are there in case error
683  * checking becomes a requirement.
684  */
685 #define png_float(png_ptr, fixed, s) (.00001 * (fixed))
686 
687 /* The fixed point conversion performs range checking and evaluates
688  * its argument multiple times, so must be used with care. The
689  * range checking uses the PNG specification values for a signed
690  * 32 bit fixed point value except that the values are deliberately
691  * rounded-to-zero to an integral value - 21474 (21474.83 is roughly
692  * (2^31-1) * 100000). 's' is a string that describes the value being
693  * converted.
694  *
695  * NOTE: this macro will raise a png_error if the range check fails,
696  * therefore it is normally only appropriate to use this on values
697  * that come from API calls or other sources where an out of range
698  * error indicates a programming error, not a data error!
699  *
700  * NOTE: by default this is off - the macro is not used - because the
701  * function call saves a lot of code.
702  */
703 #ifdef PNG_FIXED_POINT_MACRO_SUPPORTED
704 #define png_fixed(png_ptr, fp, s) ((fp) <= 21474 && (fp) >= -21474 ?\
705  ((png_fixed_point)(100000 * (fp))) : (png_fixed_error(png_ptr, s),0))
706 #endif
707 /* else the corresponding function is defined below, inside the scope of the
708  * cplusplus test.
709  */
710 #endif
711 
712 /* Constants for known chunk types. If you need to add a chunk, define the name
713  * here. For historical reasons these constants have the form png_<name>; i.e.
714  * the prefix is lower case. Please use decimal values as the parameters to
715  * match the ISO PNG specification and to avoid relying on the C locale
716  * interpretation of character values.
717  *
718  * Prior to 1.5.6 these constants were strings, as of 1.5.6 png_uint_32 values
719  * are computed and a new macro (PNG_STRING_FROM_CHUNK) added to allow a string
720  * to be generated if required.
721  *
722  * PNG_32b correctly produces a value shifted by up to 24 bits, even on
723  * architectures where (int) is only 16 bits.
724  */
725 #define PNG_32b(b,s) ((png_uint_32)(b) << (s))
726 #define PNG_U32(b1,b2,b3,b4) \
727  (PNG_32b(b1,24) | PNG_32b(b2,16) | PNG_32b(b3,8) | PNG_32b(b4,0))
728 
729 /* Constants for known chunk types.
730  *
731  * MAINTAINERS: If you need to add a chunk, define the name here.
732  * For historical reasons these constants have the form png_<name>; i.e.
733  * the prefix is lower case. Please use decimal values as the parameters to
734  * match the ISO PNG specification and to avoid relying on the C locale
735  * interpretation of character values. Please keep the list sorted.
736  *
737  * Notice that PNG_U32 is used to define a 32-bit value for the 4 byte chunk
738  * type. In fact the specification does not express chunk types this way,
739  * however using a 32-bit value means that the chunk type can be read from the
740  * stream using exactly the same code as used for a 32-bit unsigned value and
741  * can be examined far more efficiently (using one arithmetic compare).
742  *
743  * Prior to 1.5.6 the chunk type constants were expressed as C strings. The
744  * libpng API still uses strings for 'unknown' chunks and a macro,
745  * PNG_STRING_FROM_CHUNK, allows a string to be generated if required. Notice
746  * that for portable code numeric values must still be used; the string "IHDR"
747  * is not portable and neither is PNG_U32('I', 'H', 'D', 'R').
748  *
749  * In 1.7.0 the definitions will be made public in png.h to avoid having to
750  * duplicate the same definitions in application code.
751  */
752 #define png_IDAT PNG_U32( 73, 68, 65, 84)
753 #define png_IEND PNG_U32( 73, 69, 78, 68)
754 #define png_IHDR PNG_U32( 73, 72, 68, 82)
755 #define png_PLTE PNG_U32( 80, 76, 84, 69)
756 #define png_bKGD PNG_U32( 98, 75, 71, 68)
757 #define png_cHRM PNG_U32( 99, 72, 82, 77)
758 #define png_fRAc PNG_U32(102, 82, 65, 99) /* registered, not defined */
759 #define png_gAMA PNG_U32(103, 65, 77, 65)
760 #define png_gIFg PNG_U32(103, 73, 70, 103)
761 #define png_gIFt PNG_U32(103, 73, 70, 116) /* deprecated */
762 #define png_gIFx PNG_U32(103, 73, 70, 120)
763 #define png_hIST PNG_U32(104, 73, 83, 84)
764 #define png_iCCP PNG_U32(105, 67, 67, 80)
765 #define png_iTXt PNG_U32(105, 84, 88, 116)
766 #define png_oFFs PNG_U32(111, 70, 70, 115)
767 #define png_pCAL PNG_U32(112, 67, 65, 76)
768 #define png_pHYs PNG_U32(112, 72, 89, 115)
769 #define png_sBIT PNG_U32(115, 66, 73, 84)
770 #define png_sCAL PNG_U32(115, 67, 65, 76)
771 #define png_sPLT PNG_U32(115, 80, 76, 84)
772 #define png_sRGB PNG_U32(115, 82, 71, 66)
773 #define png_sTER PNG_U32(115, 84, 69, 82)
774 #define png_tEXt PNG_U32(116, 69, 88, 116)
775 #define png_tIME PNG_U32(116, 73, 77, 69)
776 #define png_tRNS PNG_U32(116, 82, 78, 83)
777 #define png_zTXt PNG_U32(122, 84, 88, 116)
778 
779 /* The following will work on (signed char*) strings, whereas the get_uint_32
780  * macro will fail on top-bit-set values because of the sign extension.
781  */
782 #define PNG_CHUNK_FROM_STRING(s)\
783  PNG_U32(0xff&(s)[0], 0xff&(s)[1], 0xff&(s)[2], 0xff&(s)[3])
784 
785 /* This uses (char), not (png_byte) to avoid warnings on systems where (char) is
786  * signed and the argument is a (char[]) This macro will fail miserably on
787  * systems where (char) is more than 8 bits.
788  */
789 #define PNG_STRING_FROM_CHUNK(s,c)\
790  (void)(((char*)(s))[0]=(char)((c)>>24), ((char*)(s))[1]=(char)((c)>>16),\
791  ((char*)(s))[2]=(char)((c)>>8), ((char*)(s))[3]=(char)((c)))
792 
793 /* Do the same but terminate with a null character. */
794 #define PNG_CSTRING_FROM_CHUNK(s,c)\
795  (void)(PNG_STRING_FROM_CHUNK(s,c), ((char*)(s))[4] = 0)
796 
797 /* Test on flag values as defined in the spec (section 5.4): */
798 #define PNG_CHUNK_ANCILLARY(c) (1 & ((c) >> 29))
799 #define PNG_CHUNK_CRITICAL(c) (!PNG_CHUNK_ANCILLARY(c))
800 #define PNG_CHUNK_PRIVATE(c) (1 & ((c) >> 21))
801 #define PNG_CHUNK_RESERVED(c) (1 & ((c) >> 13))
802 #define PNG_CHUNK_SAFE_TO_COPY(c) (1 & ((c) >> 5))
803 
804 /* Gamma values (new at libpng-1.5.4): */
805 #define PNG_GAMMA_MAC_OLD 151724 /* Assume '1.8' is really 2.2/1.45! */
806 #define PNG_GAMMA_MAC_INVERSE 65909
807 #define PNG_GAMMA_sRGB_INVERSE 45455
808 
809 /* Almost everything below is C specific; the #defines above can be used in
810  * non-C code (so long as it is C-preprocessed) the rest of this stuff cannot.
811  */
812 #ifndef PNG_VERSION_INFO_ONLY
813 
814 #include "pngstruct.h"
815 #include "pnginfo.h"
816 
817 /* Validate the include paths - the include path used to generate pnglibconf.h
818  * must match that used in the build, or we must be using pnglibconf.h.prebuilt:
819  */
820 #if PNG_ZLIB_VERNUM != 0 && PNG_ZLIB_VERNUM != ZLIB_VERNUM
821 # error ZLIB_VERNUM != PNG_ZLIB_VERNUM \
822  "-I (include path) error: see the notes in pngpriv.h"
823  /* This means that when pnglibconf.h was built the copy of zlib.h that it
824  * used is not the same as the one being used here. Because the build of
825  * libpng makes decisions to use inflateInit2 and inflateReset2 based on the
826  * zlib version number and because this affects handling of certain broken
827  * PNG files the -I directives must match.
828  *
829  * The most likely explanation is that you passed a -I in CFLAGS. This will
830  * not work; all the preprocessor directories and in particular all the -I
831  * directives must be in CPPFLAGS.
832  */
833 #endif
834 
835 /* This is used for 16 bit gamma tables -- only the top level pointers are
836  * const; this could be changed:
837  */
838 typedef const png_uint_16p * png_const_uint_16pp;
839 
840 /* Added to libpng-1.5.7: sRGB conversion tables */
841 #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
842  defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
843 #ifdef PNG_SIMPLIFIED_READ_SUPPORTED
844 PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_table, [256]);
845  /* Convert from an sRGB encoded value 0..255 to a 16-bit linear value,
846  * 0..65535. This table gives the closest 16-bit answers (no errors).
847  */
848 #endif
849 
850 PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_base, [512]);
851 PNG_INTERNAL_DATA(const png_byte, png_sRGB_delta, [512]);
852 
853 #define PNG_sRGB_FROM_LINEAR(linear) ((png_byte)((png_sRGB_base[(linear)>>15] +\
854  ((((linear)&0x7fff)*png_sRGB_delta[(linear)>>15])>>12)) >> 8))
855  /* Given a value 'linear' in the range 0..255*65535 calculate the 8-bit sRGB
856  * encoded value with maximum error 0.646365. Note that the input is not a
857  * 16-bit value; it has been multiplied by 255! */
858 #endif /* SIMPLIFIED_READ/WRITE */
859 
860 
861 /* Inhibit C++ name-mangling for libpng functions but not for system calls. */
862 #ifdef __cplusplus
863 extern "C" {
864 #endif /* __cplusplus */
865 
866 /* Internal functions; these are not exported from a DLL however because they
867  * are used within several of the C source files they have to be C extern.
868  *
869  * All of these functions must be declared with PNG_INTERNAL_FUNCTION.
870  */
871 
872 /* Zlib support */
873 #define PNG_UNEXPECTED_ZLIB_RETURN (-7)
874 PNG_INTERNAL_FUNCTION(void, png_zstream_error,(png_structrp png_ptr, int ret),
875  PNG_EMPTY);
876  /* Used by the zlib handling functions to ensure that z_stream::msg is always
877  * set before they return.
878  */
879 
880 #ifdef PNG_WRITE_SUPPORTED
881 PNG_INTERNAL_FUNCTION(void,png_free_buffer_list,(png_structrp png_ptr,
882  png_compression_bufferp *list),PNG_EMPTY);
883  /* Free the buffer list used by the compressed write code. */
884 #endif
885 
886 #if defined(PNG_FLOATING_POINT_SUPPORTED) && \
887  !defined(PNG_FIXED_POINT_MACRO_SUPPORTED) && \
888  (defined(PNG_gAMA_SUPPORTED) || defined(PNG_cHRM_SUPPORTED) || \
889  defined(PNG_sCAL_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) || \
890  defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)) || \
891  (defined(PNG_sCAL_SUPPORTED) && \
892  defined(PNG_FLOATING_ARITHMETIC_SUPPORTED))
893 PNG_INTERNAL_FUNCTION(png_fixed_point,png_fixed,(png_const_structrp png_ptr,
894  double fp, png_const_charp text),PNG_EMPTY);
895 #endif
896 
897 /* Check the user version string for compatibility, returns false if the version
898  * numbers aren't compatible.
899  */
900 PNG_INTERNAL_FUNCTION(int,png_user_version_check,(png_structrp png_ptr,
901  png_const_charp user_png_ver),PNG_EMPTY);
902 
903 /* Internal base allocator - no messages, NULL on failure to allocate. This
904  * does, however, call the application provided allocator and that could call
905  * png_error (although that would be a bug in the application implementation.)
906  */
907 PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_base,(png_const_structrp png_ptr,
908  png_alloc_size_t size),PNG_ALLOCATED);
909 
910 #if defined(PNG_TEXT_SUPPORTED) || defined(PNG_sPLT_SUPPORTED) ||\
911  defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED)
912 /* Internal array allocator, outputs no error or warning messages on failure,
913  * just returns NULL.
914  */
915 PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_array,(png_const_structrp png_ptr,
916  int nelements, size_t element_size),PNG_ALLOCATED);
917 
918 /* The same but an existing array is extended by add_elements. This function
919  * also memsets the new elements to 0 and copies the old elements. The old
920  * array is not freed or altered.
921  */
922 PNG_INTERNAL_FUNCTION(png_voidp,png_realloc_array,(png_const_structrp png_ptr,
923  png_const_voidp array, int old_elements, int add_elements,
924  size_t element_size),PNG_ALLOCATED);
925 #endif /* text, sPLT or unknown chunks */
926 
927 /* Magic to create a struct when there is no struct to call the user supplied
928  * memory allocators. Because error handling has not been set up the memory
929  * handlers can't safely call png_error, but this is an obscure and undocumented
930  * restriction so libpng has to assume that the 'free' handler, at least, might
931  * call png_error.
932  */
933 PNG_INTERNAL_FUNCTION(png_structp,png_create_png_struct,
934  (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
935  png_error_ptr warn_fn, png_voidp mem_ptr, png_malloc_ptr malloc_fn,
936  png_free_ptr free_fn),PNG_ALLOCATED);
937 
938 /* Free memory from internal libpng struct */
939 PNG_INTERNAL_FUNCTION(void,png_destroy_png_struct,(png_structrp png_ptr),
940  PNG_EMPTY);
941 
942 /* Free an allocated jmp_buf (always succeeds) */
943 PNG_INTERNAL_FUNCTION(void,png_free_jmpbuf,(png_structrp png_ptr),PNG_EMPTY);
944 
945 /* Function to allocate memory for zlib. PNGAPI is disallowed. */
946 PNG_INTERNAL_FUNCTION(voidpf,png_zalloc,(voidpf png_ptr, uInt items, uInt size),
947  PNG_ALLOCATED);
948 
949 /* Function to free memory for zlib. PNGAPI is disallowed. */
950 PNG_INTERNAL_FUNCTION(void,png_zfree,(voidpf png_ptr, voidpf ptr),PNG_EMPTY);
951 
952 /* Next four functions are used internally as callbacks. PNGCBAPI is required
953  * but not PNG_EXPORT. PNGAPI added at libpng version 1.2.3, changed to
954  * PNGCBAPI at 1.5.0
955  */
956 
957 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_read_data,(png_structp png_ptr,
958  png_bytep data, png_size_t length),PNG_EMPTY);
959 
960 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
961 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_push_fill_buffer,(png_structp png_ptr,
962  png_bytep buffer, png_size_t length),PNG_EMPTY);
963 #endif
964 
965 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_write_data,(png_structp png_ptr,
966  png_bytep data, png_size_t length),PNG_EMPTY);
967 
968 #ifdef PNG_WRITE_FLUSH_SUPPORTED
969 # ifdef PNG_STDIO_SUPPORTED
970 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_flush,(png_structp png_ptr),
971  PNG_EMPTY);
972 # endif
973 #endif
974 
975 /* Reset the CRC variable */
976 PNG_INTERNAL_FUNCTION(void,png_reset_crc,(png_structrp png_ptr),PNG_EMPTY);
977 
978 /* Write the "data" buffer to whatever output you are using */
979 PNG_INTERNAL_FUNCTION(void,png_write_data,(png_structrp png_ptr,
980  png_const_bytep data, png_size_t length),PNG_EMPTY);
981 
982 /* Read and check the PNG file signature */
983 PNG_INTERNAL_FUNCTION(void,png_read_sig,(png_structrp png_ptr,
984  png_inforp info_ptr),PNG_EMPTY);
985 
986 /* Read the chunk header (length + type name) */
987 PNG_INTERNAL_FUNCTION(png_uint_32,png_read_chunk_header,(png_structrp png_ptr),
988  PNG_EMPTY);
989 
990 /* Read data from whatever input you are using into the "data" buffer */
991 PNG_INTERNAL_FUNCTION(void,png_read_data,(png_structrp png_ptr, png_bytep data,
992  png_size_t length),PNG_EMPTY);
993 
994 /* Read bytes into buf, and update png_ptr->crc */
995 PNG_INTERNAL_FUNCTION(void,png_crc_read,(png_structrp png_ptr, png_bytep buf,
996  png_uint_32 length),PNG_EMPTY);
997 
998 /* Read "skip" bytes, read the file crc, and (optionally) verify png_ptr->crc */
999 PNG_INTERNAL_FUNCTION(int,png_crc_finish,(png_structrp png_ptr,
1000  png_uint_32 skip),PNG_EMPTY);
1001 
1002 /* Read the CRC from the file and compare it to the libpng calculated CRC */
1003 PNG_INTERNAL_FUNCTION(int,png_crc_error,(png_structrp png_ptr),PNG_EMPTY);
1004 
1005 /* Calculate the CRC over a section of data. Note that we are only
1006  * passing a maximum of 64K on systems that have this as a memory limit,
1007  * since this is the maximum buffer size we can specify.
1008  */
1009 PNG_INTERNAL_FUNCTION(void,png_calculate_crc,(png_structrp png_ptr,
1010  png_const_bytep ptr, png_size_t length),PNG_EMPTY);
1011 
1012 #ifdef PNG_WRITE_FLUSH_SUPPORTED
1013 PNG_INTERNAL_FUNCTION(void,png_flush,(png_structrp png_ptr),PNG_EMPTY);
1014 #endif
1015 
1016 /* Write various chunks */
1017 
1018 /* Write the IHDR chunk, and update the png_struct with the necessary
1019  * information.
1020  */
1021 PNG_INTERNAL_FUNCTION(void,png_write_IHDR,(png_structrp png_ptr,
1022  png_uint_32 width, png_uint_32 height, int bit_depth, int color_type,
1023  int compression_method, int filter_method, int interlace_method),PNG_EMPTY);
1024 
1025 PNG_INTERNAL_FUNCTION(void,png_write_PLTE,(png_structrp png_ptr,
1026  png_const_colorp palette, png_uint_32 num_pal),PNG_EMPTY);
1027 
1028 PNG_INTERNAL_FUNCTION(void,png_compress_IDAT,(png_structrp png_ptr,
1029  png_const_bytep row_data, png_alloc_size_t row_data_length, int flush),
1030  PNG_EMPTY);
1031 
1032 PNG_INTERNAL_FUNCTION(void,png_write_IEND,(png_structrp png_ptr),PNG_EMPTY);
1033 
1034 #ifdef PNG_WRITE_gAMA_SUPPORTED
1035 PNG_INTERNAL_FUNCTION(void,png_write_gAMA_fixed,(png_structrp png_ptr,
1036  png_fixed_point file_gamma),PNG_EMPTY);
1037 #endif
1038 
1039 #ifdef PNG_WRITE_sBIT_SUPPORTED
1040 PNG_INTERNAL_FUNCTION(void,png_write_sBIT,(png_structrp png_ptr,
1041  png_const_color_8p sbit, int color_type),PNG_EMPTY);
1042 #endif
1043 
1044 #ifdef PNG_WRITE_cHRM_SUPPORTED
1045 PNG_INTERNAL_FUNCTION(void,png_write_cHRM_fixed,(png_structrp png_ptr,
1046  const png_xy *xy), PNG_EMPTY);
1047  /* The xy value must have been previously validated */
1048 #endif
1049 
1050 #ifdef PNG_WRITE_sRGB_SUPPORTED
1051 PNG_INTERNAL_FUNCTION(void,png_write_sRGB,(png_structrp png_ptr,
1052  int intent),PNG_EMPTY);
1053 #endif
1054 
1055 #ifdef PNG_WRITE_iCCP_SUPPORTED
1056 PNG_INTERNAL_FUNCTION(void,png_write_iCCP,(png_structrp png_ptr,
1057  png_const_charp name, png_const_bytep profile), PNG_EMPTY);
1058  /* The profile must have been previously validated for correctness, the
1059  * length comes from the first four bytes. Only the base, deflate,
1060  * compression is supported.
1061  */
1062 #endif
1063 
1064 #ifdef PNG_WRITE_sPLT_SUPPORTED
1065 PNG_INTERNAL_FUNCTION(void,png_write_sPLT,(png_structrp png_ptr,
1066  png_const_sPLT_tp palette),PNG_EMPTY);
1067 #endif
1068 
1069 #ifdef PNG_WRITE_tRNS_SUPPORTED
1070 PNG_INTERNAL_FUNCTION(void,png_write_tRNS,(png_structrp png_ptr,
1071  png_const_bytep trans, png_const_color_16p values, int number,
1072  int color_type),PNG_EMPTY);
1073 #endif
1074 
1075 #ifdef PNG_WRITE_bKGD_SUPPORTED
1076 PNG_INTERNAL_FUNCTION(void,png_write_bKGD,(png_structrp png_ptr,
1077  png_const_color_16p values, int color_type),PNG_EMPTY);
1078 #endif
1079 
1080 #ifdef PNG_WRITE_hIST_SUPPORTED
1081 PNG_INTERNAL_FUNCTION(void,png_write_hIST,(png_structrp png_ptr,
1082  png_const_uint_16p hist, int num_hist),PNG_EMPTY);
1083 #endif
1084 
1085 /* Chunks that have keywords */
1086 #ifdef PNG_WRITE_tEXt_SUPPORTED
1087 PNG_INTERNAL_FUNCTION(void,png_write_tEXt,(png_structrp png_ptr,
1088  png_const_charp key, png_const_charp text, png_size_t text_len),PNG_EMPTY);
1089 #endif
1090 
1091 #ifdef PNG_WRITE_zTXt_SUPPORTED
1092 PNG_INTERNAL_FUNCTION(void,png_write_zTXt,(png_structrp png_ptr, png_const_charp
1093  key, png_const_charp text, int compression),PNG_EMPTY);
1094 #endif
1095 
1096 #ifdef PNG_WRITE_iTXt_SUPPORTED
1097 PNG_INTERNAL_FUNCTION(void,png_write_iTXt,(png_structrp png_ptr,
1098  int compression, png_const_charp key, png_const_charp lang,
1099  png_const_charp lang_key, png_const_charp text),PNG_EMPTY);
1100 #endif
1101 
1102 #ifdef PNG_TEXT_SUPPORTED /* Added at version 1.0.14 and 1.2.4 */
1103 PNG_INTERNAL_FUNCTION(int,png_set_text_2,(png_const_structrp png_ptr,
1104  png_inforp info_ptr, png_const_textp text_ptr, int num_text),PNG_EMPTY);
1105 #endif
1106 
1107 #ifdef PNG_WRITE_oFFs_SUPPORTED
1108 PNG_INTERNAL_FUNCTION(void,png_write_oFFs,(png_structrp png_ptr,
1109  png_int_32 x_offset, png_int_32 y_offset, int unit_type),PNG_EMPTY);
1110 #endif
1111 
1112 #ifdef PNG_WRITE_pCAL_SUPPORTED
1113 PNG_INTERNAL_FUNCTION(void,png_write_pCAL,(png_structrp png_ptr,
1114  png_charp purpose, png_int_32 X0, png_int_32 X1, int type, int nparams,
1115  png_const_charp units, png_charpp params),PNG_EMPTY);
1116 #endif
1117 
1118 #ifdef PNG_WRITE_pHYs_SUPPORTED
1119 PNG_INTERNAL_FUNCTION(void,png_write_pHYs,(png_structrp png_ptr,
1120  png_uint_32 x_pixels_per_unit, png_uint_32 y_pixels_per_unit,
1121  int unit_type),PNG_EMPTY);
1122 #endif
1123 
1124 #ifdef PNG_WRITE_tIME_SUPPORTED
1125 PNG_INTERNAL_FUNCTION(void,png_write_tIME,(png_structrp png_ptr,
1126  png_const_timep mod_time),PNG_EMPTY);
1127 #endif
1128 
1129 #ifdef PNG_WRITE_sCAL_SUPPORTED
1130 PNG_INTERNAL_FUNCTION(void,png_write_sCAL_s,(png_structrp png_ptr,
1131  int unit, png_const_charp width, png_const_charp height),PNG_EMPTY);
1132 #endif
1133 
1134 /* Called when finished processing a row of data */
1135 PNG_INTERNAL_FUNCTION(void,png_write_finish_row,(png_structrp png_ptr),
1136  PNG_EMPTY);
1137 
1138 /* Internal use only. Called before first row of data */
1139 PNG_INTERNAL_FUNCTION(void,png_write_start_row,(png_structrp png_ptr),
1140  PNG_EMPTY);
1141 
1142 /* Combine a row of data, dealing with alpha, etc. if requested. 'row' is an
1143  * array of png_ptr->width pixels. If the image is not interlaced or this
1144  * is the final pass this just does a memcpy, otherwise the "display" flag
1145  * is used to determine whether to copy pixels that are not in the current pass.
1146  *
1147  * Because 'png_do_read_interlace' (below) replicates pixels this allows this
1148  * function to achieve the documented 'blocky' appearance during interlaced read
1149  * if display is 1 and the 'sparkle' appearance, where existing pixels in 'row'
1150  * are not changed if they are not in the current pass, when display is 0.
1151  *
1152  * 'display' must be 0 or 1, otherwise the memcpy will be done regardless.
1153  *
1154  * The API always reads from the png_struct row buffer and always assumes that
1155  * it is full width (png_do_read_interlace has already been called.)
1156  *
1157  * This function is only ever used to write to row buffers provided by the
1158  * caller of the relevant libpng API and the row must have already been
1159  * transformed by the read transformations.
1160  *
1161  * The PNG_USE_COMPILE_TIME_MASKS option causes generation of pre-computed
1162  * bitmasks for use within the code, otherwise runtime generated masks are used.
1163  * The default is compile time masks.
1164  */
1165 #ifndef PNG_USE_COMPILE_TIME_MASKS
1166 # define PNG_USE_COMPILE_TIME_MASKS 1
1167 #endif
1168 PNG_INTERNAL_FUNCTION(void,png_combine_row,(png_const_structrp png_ptr,
1169  png_bytep row, int display),PNG_EMPTY);
1170 
1171 #ifdef PNG_READ_INTERLACING_SUPPORTED
1172 /* Expand an interlaced row: the 'row_info' describes the pass data that has
1173  * been read in and must correspond to the pixels in 'row', the pixels are
1174  * expanded (moved apart) in 'row' to match the final layout, when doing this
1175  * the pixels are *replicated* to the intervening space. This is essential for
1176  * the correct operation of png_combine_row, above.
1177  */
1178 PNG_INTERNAL_FUNCTION(void,png_do_read_interlace,(png_row_infop row_info,
1179  png_bytep row, int pass, png_uint_32 transformations),PNG_EMPTY);
1180 #endif
1181 
1182 /* GRR TO DO (2.0 or whenever): simplify other internal calling interfaces */
1183 
1184 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1185 /* Grab pixels out of a row for an interlaced pass */
1186 PNG_INTERNAL_FUNCTION(void,png_do_write_interlace,(png_row_infop row_info,
1187  png_bytep row, int pass),PNG_EMPTY);
1188 #endif
1189 
1190 /* Unfilter a row: check the filter value before calling this, there is no point
1191  * calling it for PNG_FILTER_VALUE_NONE.
1192  */
1193 PNG_INTERNAL_FUNCTION(void,png_read_filter_row,(png_structrp pp, png_row_infop
1194  row_info, png_bytep row, png_const_bytep prev_row, int filter),PNG_EMPTY);
1195 
1196 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_up_neon,(png_row_infop row_info,
1197  png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1198 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_neon,(png_row_infop
1199  row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1200 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_neon,(png_row_infop
1201  row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1202 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_neon,(png_row_infop
1203  row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1204 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_neon,(png_row_infop
1205  row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1206 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_neon,(png_row_infop
1207  row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1208 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_neon,(png_row_infop
1209  row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1210 
1211 /* Choose the best filter to use and filter the row data */
1212 PNG_INTERNAL_FUNCTION(void,png_write_find_filter,(png_structrp png_ptr,
1213  png_row_infop row_info),PNG_EMPTY);
1214 
1215 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1216 PNG_INTERNAL_FUNCTION(void,png_read_IDAT_data,(png_structrp png_ptr,
1217  png_bytep output, png_alloc_size_t avail_out),PNG_EMPTY);
1218  /* Read 'avail_out' bytes of data from the IDAT stream. If the output buffer
1219  * is NULL the function checks, instead, for the end of the stream. In this
1220  * case a benign error will be issued if the stream end is not found or if
1221  * extra data has to be consumed.
1222  */
1223 PNG_INTERNAL_FUNCTION(void,png_read_finish_IDAT,(png_structrp png_ptr),
1224  PNG_EMPTY);
1225  /* This cleans up when the IDAT LZ stream does not end when the last image
1226  * byte is read; there is still some pending input.
1227  */
1228 
1229 PNG_INTERNAL_FUNCTION(void,png_read_finish_row,(png_structrp png_ptr),
1230  PNG_EMPTY);
1231  /* Finish a row while reading, dealing with interlacing passes, etc. */
1232 #endif /* SEQUENTIAL_READ */
1233 
1234 /* Initialize the row buffers, etc. */
1235 PNG_INTERNAL_FUNCTION(void,png_read_start_row,(png_structrp png_ptr),PNG_EMPTY);
1236 
1237 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1238 /* Optional call to update the users info structure */
1239 PNG_INTERNAL_FUNCTION(void,png_read_transform_info,(png_structrp png_ptr,
1240  png_inforp info_ptr),PNG_EMPTY);
1241 #endif
1242 
1243 /* Shared transform functions, defined in pngtran.c */
1244 #if defined(PNG_WRITE_FILLER_SUPPORTED) || \
1245  defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
1246 PNG_INTERNAL_FUNCTION(void,png_do_strip_channel,(png_row_infop row_info,
1247  png_bytep row, int at_start),PNG_EMPTY);
1248 #endif
1249 
1250 #ifdef PNG_16BIT_SUPPORTED
1251 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
1252 PNG_INTERNAL_FUNCTION(void,png_do_swap,(png_row_infop row_info,
1253  png_bytep row),PNG_EMPTY);
1254 #endif
1255 #endif
1256 
1257 #if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
1258  defined(PNG_WRITE_PACKSWAP_SUPPORTED)
1259 PNG_INTERNAL_FUNCTION(void,png_do_packswap,(png_row_infop row_info,
1260  png_bytep row),PNG_EMPTY);
1261 #endif
1262 
1263 #if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
1264 PNG_INTERNAL_FUNCTION(void,png_do_invert,(png_row_infop row_info,
1265  png_bytep row),PNG_EMPTY);
1266 #endif
1267 
1268 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
1269 PNG_INTERNAL_FUNCTION(void,png_do_bgr,(png_row_infop row_info,
1270  png_bytep row),PNG_EMPTY);
1271 #endif
1272 
1273 /* The following decodes the appropriate chunks, and does error correction,
1274  * then calls the appropriate callback for the chunk if it is valid.
1275  */
1276 
1277 /* Decode the IHDR chunk */
1278 PNG_INTERNAL_FUNCTION(void,png_handle_IHDR,(png_structrp png_ptr,
1279  png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1280 PNG_INTERNAL_FUNCTION(void,png_handle_PLTE,(png_structrp png_ptr,
1281  png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1282 PNG_INTERNAL_FUNCTION(void,png_handle_IEND,(png_structrp png_ptr,
1283  png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1284 
1285 #ifdef PNG_READ_bKGD_SUPPORTED
1286 PNG_INTERNAL_FUNCTION(void,png_handle_bKGD,(png_structrp png_ptr,
1287  png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1288 #endif
1289 
1290 #ifdef PNG_READ_cHRM_SUPPORTED
1291 PNG_INTERNAL_FUNCTION(void,png_handle_cHRM,(png_structrp png_ptr,
1292  png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1293 #endif
1294 
1295 #ifdef PNG_READ_gAMA_SUPPORTED
1296 PNG_INTERNAL_FUNCTION(void,png_handle_gAMA,(png_structrp png_ptr,
1297  png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1298 #endif
1299 
1300 #ifdef PNG_READ_hIST_SUPPORTED
1301 PNG_INTERNAL_FUNCTION(void,png_handle_hIST,(png_structrp png_ptr,
1302  png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1303 #endif
1304 
1305 #ifdef PNG_READ_iCCP_SUPPORTED
1306 PNG_INTERNAL_FUNCTION(void,png_handle_iCCP,(png_structrp png_ptr,
1307  png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1308 #endif /* READ_iCCP */
1309 
1310 #ifdef PNG_READ_iTXt_SUPPORTED
1311 PNG_INTERNAL_FUNCTION(void,png_handle_iTXt,(png_structrp png_ptr,
1312  png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1313 #endif
1314 
1315 #ifdef PNG_READ_oFFs_SUPPORTED
1316 PNG_INTERNAL_FUNCTION(void,png_handle_oFFs,(png_structrp png_ptr,
1317  png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1318 #endif
1319 
1320 #ifdef PNG_READ_pCAL_SUPPORTED
1321 PNG_INTERNAL_FUNCTION(void,png_handle_pCAL,(png_structrp png_ptr,
1322  png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1323 #endif
1324 
1325 #ifdef PNG_READ_pHYs_SUPPORTED
1326 PNG_INTERNAL_FUNCTION(void,png_handle_pHYs,(png_structrp png_ptr,
1327  png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1328 #endif
1329 
1330 #ifdef PNG_READ_sBIT_SUPPORTED
1331 PNG_INTERNAL_FUNCTION(void,png_handle_sBIT,(png_structrp png_ptr,
1332  png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1333 #endif
1334 
1335 #ifdef PNG_READ_sCAL_SUPPORTED
1336 PNG_INTERNAL_FUNCTION(void,png_handle_sCAL,(png_structrp png_ptr,
1337  png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1338 #endif
1339 
1340 #ifdef PNG_READ_sPLT_SUPPORTED
1341 PNG_INTERNAL_FUNCTION(void,png_handle_sPLT,(png_structrp png_ptr,
1342  png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1343 #endif /* READ_sPLT */
1344 
1345 #ifdef PNG_READ_sRGB_SUPPORTED
1346 PNG_INTERNAL_FUNCTION(void,png_handle_sRGB,(png_structrp png_ptr,
1347  png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1348 #endif
1349 
1350 #ifdef PNG_READ_tEXt_SUPPORTED
1351 PNG_INTERNAL_FUNCTION(void,png_handle_tEXt,(png_structrp png_ptr,
1352  png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1353 #endif
1354 
1355 #ifdef PNG_READ_tIME_SUPPORTED
1356 PNG_INTERNAL_FUNCTION(void,png_handle_tIME,(png_structrp png_ptr,
1357  png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1358 #endif
1359 
1360 #ifdef PNG_READ_tRNS_SUPPORTED
1361 PNG_INTERNAL_FUNCTION(void,png_handle_tRNS,(png_structrp png_ptr,
1362  png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1363 #endif
1364 
1365 #ifdef PNG_READ_zTXt_SUPPORTED
1366 PNG_INTERNAL_FUNCTION(void,png_handle_zTXt,(png_structrp png_ptr,
1367  png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1368 #endif
1369 
1370 PNG_INTERNAL_FUNCTION(void,png_check_chunk_name,(png_structrp png_ptr,
1371  png_uint_32 chunk_name),PNG_EMPTY);
1372 
1373 PNG_INTERNAL_FUNCTION(void,png_handle_unknown,(png_structrp png_ptr,
1374  png_inforp info_ptr, png_uint_32 length, int keep),PNG_EMPTY);
1375  /* This is the function that gets called for unknown chunks. The 'keep'
1376  * argument is either non-zero for a known chunk that has been set to be
1377  * handled as unknown or zero for an unknown chunk. By default the function
1378  * just skips the chunk or errors out if it is critical.
1379  */
1380 
1381 #if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) ||\
1382  defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
1383 PNG_INTERNAL_FUNCTION(int,png_chunk_unknown_handling,
1384  (png_const_structrp png_ptr, png_uint_32 chunk_name),PNG_EMPTY);
1385  /* Exactly as the API png_handle_as_unknown() except that the argument is a
1386  * 32-bit chunk name, not a string.
1387  */
1388 #endif /* READ_UNKNOWN_CHUNKS || HANDLE_AS_UNKNOWN */
1389 
1390 /* Handle the transformations for reading and writing */
1391 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1392 PNG_INTERNAL_FUNCTION(void,png_do_read_transformations,(png_structrp png_ptr,
1393  png_row_infop row_info),PNG_EMPTY);
1394 #endif
1395 #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
1396 PNG_INTERNAL_FUNCTION(void,png_do_write_transformations,(png_structrp png_ptr,
1397  png_row_infop row_info),PNG_EMPTY);
1398 #endif
1399 
1400 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1401 PNG_INTERNAL_FUNCTION(void,png_init_read_transformations,(png_structrp png_ptr),
1402  PNG_EMPTY);
1403 #endif
1404 
1405 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1406 PNG_INTERNAL_FUNCTION(void,png_push_read_chunk,(png_structrp png_ptr,
1407  png_inforp info_ptr),PNG_EMPTY);
1408 PNG_INTERNAL_FUNCTION(void,png_push_read_sig,(png_structrp png_ptr,
1409  png_inforp info_ptr),PNG_EMPTY);
1410 PNG_INTERNAL_FUNCTION(void,png_push_check_crc,(png_structrp png_ptr),PNG_EMPTY);
1411 PNG_INTERNAL_FUNCTION(void,png_push_crc_skip,(png_structrp png_ptr,
1412  png_uint_32 length),PNG_EMPTY);
1413 PNG_INTERNAL_FUNCTION(void,png_push_crc_finish,(png_structrp png_ptr),
1414  PNG_EMPTY);
1415 PNG_INTERNAL_FUNCTION(void,png_push_save_buffer,(png_structrp png_ptr),
1416  PNG_EMPTY);
1417 PNG_INTERNAL_FUNCTION(void,png_push_restore_buffer,(png_structrp png_ptr,
1418  png_bytep buffer, png_size_t buffer_length),PNG_EMPTY);
1419 PNG_INTERNAL_FUNCTION(void,png_push_read_IDAT,(png_structrp png_ptr),PNG_EMPTY);
1420 PNG_INTERNAL_FUNCTION(void,png_process_IDAT_data,(png_structrp png_ptr,
1421  png_bytep buffer, png_size_t buffer_length),PNG_EMPTY);
1422 PNG_INTERNAL_FUNCTION(void,png_push_process_row,(png_structrp png_ptr),
1423  PNG_EMPTY);
1424 PNG_INTERNAL_FUNCTION(void,png_push_handle_unknown,(png_structrp png_ptr,
1425  png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1426 PNG_INTERNAL_FUNCTION(void,png_push_have_info,(png_structrp png_ptr,
1427  png_inforp info_ptr),PNG_EMPTY);
1428 PNG_INTERNAL_FUNCTION(void,png_push_have_end,(png_structrp png_ptr,
1429  png_inforp info_ptr),PNG_EMPTY);
1430 PNG_INTERNAL_FUNCTION(void,png_push_have_row,(png_structrp png_ptr,
1431  png_bytep row),PNG_EMPTY);
1432 PNG_INTERNAL_FUNCTION(void,png_push_read_end,(png_structrp png_ptr,
1433  png_inforp info_ptr),PNG_EMPTY);
1434 PNG_INTERNAL_FUNCTION(void,png_process_some_data,(png_structrp png_ptr,
1435  png_inforp info_ptr),PNG_EMPTY);
1436 PNG_INTERNAL_FUNCTION(void,png_read_push_finish_row,(png_structrp png_ptr),
1437  PNG_EMPTY);
1438 # ifdef PNG_READ_tEXt_SUPPORTED
1439 PNG_INTERNAL_FUNCTION(void,png_push_handle_tEXt,(png_structrp png_ptr,
1440  png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1441 PNG_INTERNAL_FUNCTION(void,png_push_read_tEXt,(png_structrp png_ptr,
1442  png_inforp info_ptr),PNG_EMPTY);
1443 # endif
1444 # ifdef PNG_READ_zTXt_SUPPORTED
1445 PNG_INTERNAL_FUNCTION(void,png_push_handle_zTXt,(png_structrp png_ptr,
1446  png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1447 PNG_INTERNAL_FUNCTION(void,png_push_read_zTXt,(png_structrp png_ptr,
1448  png_inforp info_ptr),PNG_EMPTY);
1449 # endif
1450 # ifdef PNG_READ_iTXt_SUPPORTED
1451 PNG_INTERNAL_FUNCTION(void,png_push_handle_iTXt,(png_structrp png_ptr,
1452  png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1453 PNG_INTERNAL_FUNCTION(void,png_push_read_iTXt,(png_structrp png_ptr,
1454  png_inforp info_ptr),PNG_EMPTY);
1455 # endif
1456 
1457 #endif /* PROGRESSIVE_READ */
1458 
1459 /* Added at libpng version 1.6.0 */
1460 #ifdef PNG_GAMMA_SUPPORTED
1461 PNG_INTERNAL_FUNCTION(void,png_colorspace_set_gamma,(png_const_structrp png_ptr,
1462  png_colorspacerp colorspace, png_fixed_point gAMA), PNG_EMPTY);
1463  /* Set the colorspace gamma with a value provided by the application or by
1464  * the gAMA chunk on read. The value will override anything set by an ICC
1465  * profile.
1466  */
1467 
1468 PNG_INTERNAL_FUNCTION(void,png_colorspace_sync_info,(png_const_structrp png_ptr,
1469  png_inforp info_ptr), PNG_EMPTY);
1470  /* Synchronize the info 'valid' flags with the colorspace */
1471 
1472 PNG_INTERNAL_FUNCTION(void,png_colorspace_sync,(png_const_structrp png_ptr,
1473  png_inforp info_ptr), PNG_EMPTY);
1474  /* Copy the png_struct colorspace to the info_struct and call the above to
1475  * synchronize the flags. Checks for NULL info_ptr and does nothing.
1476  */
1477 #endif
1478 
1479 /* Added at libpng version 1.4.0 */
1480 #ifdef PNG_COLORSPACE_SUPPORTED
1481 /* These internal functions are for maintaining the colorspace structure within
1482  * a png_info or png_struct (or, indeed, both).
1483  */
1484 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_chromaticities,
1485  (png_const_structrp png_ptr, png_colorspacerp colorspace, const png_xy *xy,
1486  int preferred), PNG_EMPTY);
1487 
1488 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_endpoints,
1489  (png_const_structrp png_ptr, png_colorspacerp colorspace, const png_XYZ *XYZ,
1490  int preferred), PNG_EMPTY);
1491 
1492 #ifdef PNG_sRGB_SUPPORTED
1493 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_sRGB,(png_const_structrp png_ptr,
1494  png_colorspacerp colorspace, int intent), PNG_EMPTY);
1495  /* This does set the colorspace gAMA and cHRM values too, but doesn't set the
1496  * flags to write them, if it returns false there was a problem and an error
1497  * message has already been output (but the colorspace may still need to be
1498  * synced to record the invalid flag).
1499  */
1500 #endif /* sRGB */
1501 
1502 #ifdef PNG_iCCP_SUPPORTED
1503 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_ICC,(png_const_structrp png_ptr,
1504  png_colorspacerp colorspace, png_const_charp name,
1505  png_uint_32 profile_length, png_const_bytep profile, int color_type),
1506  PNG_EMPTY);
1507  /* The 'name' is used for information only */
1508 
1509 /* Routines for checking parts of an ICC profile. */
1510 PNG_INTERNAL_FUNCTION(int,png_icc_check_length,(png_const_structrp png_ptr,
1511  png_colorspacerp colorspace, png_const_charp name,
1512  png_uint_32 profile_length), PNG_EMPTY);
1513 PNG_INTERNAL_FUNCTION(int,png_icc_check_header,(png_const_structrp png_ptr,
1514  png_colorspacerp colorspace, png_const_charp name,
1515  png_uint_32 profile_length,
1516  png_const_bytep profile /* first 132 bytes only */, int color_type),
1517  PNG_EMPTY);
1518 PNG_INTERNAL_FUNCTION(int,png_icc_check_tag_table,(png_const_structrp png_ptr,
1519  png_colorspacerp colorspace, png_const_charp name,
1520  png_uint_32 profile_length,
1521  png_const_bytep profile /* header plus whole tag table */), PNG_EMPTY);
1522 #ifdef PNG_sRGB_SUPPORTED
1523 PNG_INTERNAL_FUNCTION(void,png_icc_set_sRGB,(
1524  png_const_structrp png_ptr, png_colorspacerp colorspace,
1525  png_const_bytep profile, uLong adler), PNG_EMPTY);
1526  /* 'adler' is the Adler32 checksum of the uncompressed profile data. It may
1527  * be zero to indicate that it is not available. It is used, if provided,
1528  * as a fast check on the profile when checking to see if it is sRGB.
1529  */
1530 #endif
1531 #endif /* iCCP */
1532 
1533 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1534 PNG_INTERNAL_FUNCTION(void,png_colorspace_set_rgb_coefficients,
1535  (png_structrp png_ptr), PNG_EMPTY);
1536  /* Set the rgb_to_gray coefficients from the colorspace Y values */
1537 #endif /* READ_RGB_TO_GRAY */
1538 #endif /* COLORSPACE */
1539 
1540 /* Added at libpng version 1.4.0 */
1541 PNG_INTERNAL_FUNCTION(void,png_check_IHDR,(png_const_structrp png_ptr,
1542  png_uint_32 width, png_uint_32 height, int bit_depth,
1543  int color_type, int interlace_type, int compression_type,
1544  int filter_type),PNG_EMPTY);
1545 
1546 /* Added at libpng version 1.5.10 */
1547 #if defined(PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED) || \
1548  defined(PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED)
1549 PNG_INTERNAL_FUNCTION(void,png_do_check_palette_indexes,
1550  (png_structrp png_ptr, png_row_infop row_info),PNG_EMPTY);
1551 #endif
1552 
1553 #if defined(PNG_FLOATING_POINT_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED)
1554 PNG_INTERNAL_FUNCTION(void,png_fixed_error,(png_const_structrp png_ptr,
1555  png_const_charp name),PNG_NORETURN);
1556 #endif
1557 
1558 /* Puts 'string' into 'buffer' at buffer[pos], taking care never to overwrite
1559  * the end. Always leaves the buffer nul terminated. Never errors out (and
1560  * there is no error code.)
1561  */
1562 PNG_INTERNAL_FUNCTION(size_t,png_safecat,(png_charp buffer, size_t bufsize,
1563  size_t pos, png_const_charp string),PNG_EMPTY);
1564 
1565 /* Various internal functions to handle formatted warning messages, currently
1566  * only implemented for warnings.
1567  */
1568 #if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_TIME_RFC1123_SUPPORTED)
1569 /* Utility to dump an unsigned value into a buffer, given a start pointer and
1570  * and end pointer (which should point just *beyond* the end of the buffer!)
1571  * Returns the pointer to the start of the formatted string. This utility only
1572  * does unsigned values.
1573  */
1574 PNG_INTERNAL_FUNCTION(png_charp,png_format_number,(png_const_charp start,
1575  png_charp end, int format, png_alloc_size_t number),PNG_EMPTY);
1576 
1577 /* Convenience macro that takes an array: */
1578 #define PNG_FORMAT_NUMBER(buffer,format,number) \
1579  png_format_number(buffer, buffer + (sizeof buffer), format, number)
1580 
1581 /* Suggested size for a number buffer (enough for 64 bits and a sign!) */
1582 #define PNG_NUMBER_BUFFER_SIZE 24
1583 
1584 /* These are the integer formats currently supported, the name is formed from
1585  * the standard printf(3) format string.
1586  */
1587 #define PNG_NUMBER_FORMAT_u 1 /* chose unsigned API! */
1588 #define PNG_NUMBER_FORMAT_02u 2
1589 #define PNG_NUMBER_FORMAT_d 1 /* chose signed API! */
1590 #define PNG_NUMBER_FORMAT_02d 2
1591 #define PNG_NUMBER_FORMAT_x 3
1592 #define PNG_NUMBER_FORMAT_02x 4
1593 #define PNG_NUMBER_FORMAT_fixed 5 /* choose the signed API */
1594 #endif
1595 
1596 #ifdef PNG_WARNINGS_SUPPORTED
1597 /* New defines and members adding in libpng-1.5.4 */
1598 # define PNG_WARNING_PARAMETER_SIZE 32
1599 # define PNG_WARNING_PARAMETER_COUNT 8 /* Maximum 9; see pngerror.c */
1600 
1601 /* An l-value of this type has to be passed to the APIs below to cache the
1602  * values of the parameters to a formatted warning message.
1603  */
1604 typedef char png_warning_parameters[PNG_WARNING_PARAMETER_COUNT][
1605  PNG_WARNING_PARAMETER_SIZE];
1606 
1607 PNG_INTERNAL_FUNCTION(void,png_warning_parameter,(png_warning_parameters p,
1608  int number, png_const_charp string),PNG_EMPTY);
1609  /* Parameters are limited in size to PNG_WARNING_PARAMETER_SIZE characters,
1610  * including the trailing '\0'.
1611  */
1612 PNG_INTERNAL_FUNCTION(void,png_warning_parameter_unsigned,
1613  (png_warning_parameters p, int number, int format, png_alloc_size_t value),
1614  PNG_EMPTY);
1615  /* Use png_alloc_size_t because it is an unsigned type as big as any we
1616  * need to output. Use the following for a signed value.
1617  */
1618 PNG_INTERNAL_FUNCTION(void,png_warning_parameter_signed,
1619  (png_warning_parameters p, int number, int format, png_int_32 value),
1620  PNG_EMPTY);
1621 
1622 PNG_INTERNAL_FUNCTION(void,png_formatted_warning,(png_const_structrp png_ptr,
1623  png_warning_parameters p, png_const_charp message),PNG_EMPTY);
1624  /* 'message' follows the X/Open approach of using @1, @2 to insert
1625  * parameters previously supplied using the above functions. Errors in
1626  * specifying the parameters will simply result in garbage substitutions.
1627  */
1628 #endif
1629 
1630 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
1631 /* Application errors (new in 1.6); use these functions (declared below) for
1632  * errors in the parameters or order of API function calls on read. The
1633  * 'warning' should be used for an error that can be handled completely; the
1634  * 'error' for one which can be handled safely but which may lose application
1635  * information or settings.
1636  *
1637  * By default these both result in a png_error call prior to release, while in a
1638  * released version the 'warning' is just a warning. However if the application
1639  * explicitly disables benign errors (explicitly permitting the code to lose
1640  * information) they both turn into warnings.
1641  *
1642  * If benign errors aren't supported they end up as the corresponding base call
1643  * (png_warning or png_error.)
1644  */
1645 PNG_INTERNAL_FUNCTION(void,png_app_warning,(png_const_structrp png_ptr,
1646  png_const_charp message),PNG_EMPTY);
1647  /* The application provided invalid parameters to an API function or called
1648  * an API function at the wrong time, libpng can completely recover.
1649  */
1650 
1651 PNG_INTERNAL_FUNCTION(void,png_app_error,(png_const_structrp png_ptr,
1652  png_const_charp message),PNG_EMPTY);
1653  /* As above but libpng will ignore the call, or attempt some other partial
1654  * recovery from the error.
1655  */
1656 #else
1657 # define png_app_warning(pp,s) png_warning(pp,s)
1658 # define png_app_error(pp,s) png_error(pp,s)
1659 #endif
1660 
1661 PNG_INTERNAL_FUNCTION(void,png_chunk_report,(png_const_structrp png_ptr,
1662  png_const_charp message, int error),PNG_EMPTY);
1663  /* Report a recoverable issue in chunk data. On read this is used to report
1664  * a problem found while reading a particular chunk and the
1665  * png_chunk_benign_error or png_chunk_warning function is used as
1666  * appropriate. On write this is used to report an error that comes from
1667  * data set via an application call to a png_set_ API and png_app_error or
1668  * png_app_warning is used as appropriate.
1669  *
1670  * The 'error' parameter must have one of the following values:
1671  */
1672 #define PNG_CHUNK_WARNING 0 /* never an error */
1673 #define PNG_CHUNK_WRITE_ERROR 1 /* an error only on write */
1674 #define PNG_CHUNK_ERROR 2 /* always an error */
1675 
1676 /* ASCII to FP interfaces, currently only implemented if sCAL
1677  * support is required.
1678  */
1679 #if defined(PNG_sCAL_SUPPORTED)
1680 /* MAX_DIGITS is actually the maximum number of characters in an sCAL
1681  * width or height, derived from the precision (number of significant
1682  * digits - a build time settable option) and assumptions about the
1683  * maximum ridiculous exponent.
1684  */
1685 #define PNG_sCAL_MAX_DIGITS (PNG_sCAL_PRECISION+1/*.*/+1/*E*/+10/*exponent*/)
1686 
1687 #ifdef PNG_FLOATING_POINT_SUPPORTED
1688 PNG_INTERNAL_FUNCTION(void,png_ascii_from_fp,(png_const_structrp png_ptr,
1689  png_charp ascii, png_size_t size, double fp, unsigned int precision),
1690  PNG_EMPTY);
1691 #endif /* FLOATING_POINT */
1692 
1693 #ifdef PNG_FIXED_POINT_SUPPORTED
1694 PNG_INTERNAL_FUNCTION(void,png_ascii_from_fixed,(png_const_structrp png_ptr,
1695  png_charp ascii, png_size_t size, png_fixed_point fp),PNG_EMPTY);
1696 #endif /* FIXED_POINT */
1697 #endif /* sCAL */
1698 
1699 #if defined(PNG_sCAL_SUPPORTED) || defined(PNG_pCAL_SUPPORTED)
1700 /* An internal API to validate the format of a floating point number.
1701  * The result is the index of the next character. If the number is
1702  * not valid it will be the index of a character in the supposed number.
1703  *
1704  * The format of a number is defined in the PNG extensions specification
1705  * and this API is strictly conformant to that spec, not anyone elses!
1706  *
1707  * The format as a regular expression is:
1708  *
1709  * [+-]?[0-9]+.?([Ee][+-]?[0-9]+)?
1710  *
1711  * or:
1712  *
1713  * [+-]?.[0-9]+(.[0-9]+)?([Ee][+-]?[0-9]+)?
1714  *
1715  * The complexity is that either integer or fraction must be present and the
1716  * fraction is permitted to have no digits only if the integer is present.
1717  *
1718  * NOTE: The dangling E problem.
1719  * There is a PNG valid floating point number in the following:
1720  *
1721  * PNG floating point numbers are not greedy.
1722  *
1723  * Working this out requires *TWO* character lookahead (because of the
1724  * sign), the parser does not do this - it will fail at the 'r' - this
1725  * doesn't matter for PNG sCAL chunk values, but it requires more care
1726  * if the value were ever to be embedded in something more complex. Use
1727  * ANSI-C strtod if you need the lookahead.
1728  */
1729 /* State table for the parser. */
1730 #define PNG_FP_INTEGER 0 /* before or in integer */
1731 #define PNG_FP_FRACTION 1 /* before or in fraction */
1732 #define PNG_FP_EXPONENT 2 /* before or in exponent */
1733 #define PNG_FP_STATE 3 /* mask for the above */
1734 #define PNG_FP_SAW_SIGN 4 /* Saw +/- in current state */
1735 #define PNG_FP_SAW_DIGIT 8 /* Saw a digit in current state */
1736 #define PNG_FP_SAW_DOT 16 /* Saw a dot in current state */
1737 #define PNG_FP_SAW_E 32 /* Saw an E (or e) in current state */
1738 #define PNG_FP_SAW_ANY 60 /* Saw any of the above 4 */
1739 
1740 /* These three values don't affect the parser. They are set but not used.
1741  */
1742 #define PNG_FP_WAS_VALID 64 /* Preceding substring is a valid fp number */
1743 #define PNG_FP_NEGATIVE 128 /* A negative number, including "-0" */
1744 #define PNG_FP_NONZERO 256 /* A non-zero value */
1745 #define PNG_FP_STICKY 448 /* The above three flags */
1746 
1747 /* This is available for the caller to store in 'state' if required. Do not
1748  * call the parser after setting it (the parser sometimes clears it.)
1749  */
1750 #define PNG_FP_INVALID 512 /* Available for callers as a distinct value */
1751 
1752 /* Result codes for the parser (boolean - true meants ok, false means
1753  * not ok yet.)
1754  */
1755 #define PNG_FP_MAYBE 0 /* The number may be valid in the future */
1756 #define PNG_FP_OK 1 /* The number is valid */
1757 
1758 /* Tests on the sticky non-zero and negative flags. To pass these checks
1759  * the state must also indicate that the whole number is valid - this is
1760  * achieved by testing PNG_FP_SAW_DIGIT (see the implementation for why this
1761  * is equivalent to PNG_FP_OK above.)
1762  */
1763 #define PNG_FP_NZ_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NEGATIVE | PNG_FP_NONZERO)
1764  /* NZ_MASK: the string is valid and a non-zero negative value */
1765 #define PNG_FP_Z_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NONZERO)
1766  /* Z MASK: the string is valid and a non-zero value. */
1767  /* PNG_FP_SAW_DIGIT: the string is valid. */
1768 #define PNG_FP_IS_ZERO(state) (((state) & PNG_FP_Z_MASK) == PNG_FP_SAW_DIGIT)
1769 #define PNG_FP_IS_POSITIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_Z_MASK)
1770 #define PNG_FP_IS_NEGATIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_NZ_MASK)
1771 
1772 /* The actual parser. This can be called repeatedly. It updates
1773  * the index into the string and the state variable (which must
1774  * be initialized to 0). It returns a result code, as above. There
1775  * is no point calling the parser any more if it fails to advance to
1776  * the end of the string - it is stuck on an invalid character (or
1777  * terminated by '\0').
1778  *
1779  * Note that the pointer will consume an E or even an E+ and then leave
1780  * a 'maybe' state even though a preceding integer.fraction is valid.
1781  * The PNG_FP_WAS_VALID flag indicates that a preceding substring was
1782  * a valid number. It's possible to recover from this by calling
1783  * the parser again (from the start, with state 0) but with a string
1784  * that omits the last character (i.e. set the size to the index of
1785  * the problem character.) This has not been tested within libpng.
1786  */
1787 PNG_INTERNAL_FUNCTION(int,png_check_fp_number,(png_const_charp string,
1788  png_size_t size, int *statep, png_size_tp whereami),PNG_EMPTY);
1789 
1790 /* This is the same but it checks a complete string and returns true
1791  * only if it just contains a floating point number. As of 1.5.4 this
1792  * function also returns the state at the end of parsing the number if
1793  * it was valid (otherwise it returns 0.) This can be used for testing
1794  * for negative or zero values using the sticky flag.
1795  */
1796 PNG_INTERNAL_FUNCTION(int,png_check_fp_string,(png_const_charp string,
1797  png_size_t size),PNG_EMPTY);
1798 #endif /* pCAL || sCAL */
1799 
1800 #if defined(PNG_GAMMA_SUPPORTED) ||\
1801  defined(PNG_INCH_CONVERSIONS_SUPPORTED) || defined(PNG_READ_pHYs_SUPPORTED)
1802 /* Added at libpng version 1.5.0 */
1803 /* This is a utility to provide a*times/div (rounded) and indicate
1804  * if there is an overflow. The result is a boolean - false (0)
1805  * for overflow, true (1) if no overflow, in which case *res
1806  * holds the result.
1807  */
1808 PNG_INTERNAL_FUNCTION(int,png_muldiv,(png_fixed_point_p res, png_fixed_point a,
1809  png_int_32 multiplied_by, png_int_32 divided_by),PNG_EMPTY);
1810 #endif
1811 
1812 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_INCH_CONVERSIONS_SUPPORTED)
1813 /* Same deal, but issue a warning on overflow and return 0. */
1814 PNG_INTERNAL_FUNCTION(png_fixed_point,png_muldiv_warn,
1815  (png_const_structrp png_ptr, png_fixed_point a, png_int_32 multiplied_by,
1816  png_int_32 divided_by),PNG_EMPTY);
1817 #endif
1818 
1819 #ifdef PNG_GAMMA_SUPPORTED
1820 /* Calculate a reciprocal - used for gamma values. This returns
1821  * 0 if the argument is 0 in order to maintain an undefined value;
1822  * there are no warnings.
1823  */
1824 PNG_INTERNAL_FUNCTION(png_fixed_point,png_reciprocal,(png_fixed_point a),
1825  PNG_EMPTY);
1826 
1827 #ifdef PNG_READ_GAMMA_SUPPORTED
1828 /* The same but gives a reciprocal of the product of two fixed point
1829  * values. Accuracy is suitable for gamma calculations but this is
1830  * not exact - use png_muldiv for that. Only required at present on read.
1831  */
1832 PNG_INTERNAL_FUNCTION(png_fixed_point,png_reciprocal2,(png_fixed_point a,
1833  png_fixed_point b),PNG_EMPTY);
1834 #endif
1835 
1836 /* Return true if the gamma value is significantly different from 1.0 */
1837 PNG_INTERNAL_FUNCTION(int,png_gamma_significant,(png_fixed_point gamma_value),
1838  PNG_EMPTY);
1839 #endif
1840 
1841 #ifdef PNG_READ_GAMMA_SUPPORTED
1842 /* Internal fixed point gamma correction. These APIs are called as
1843  * required to convert single values - they don't need to be fast,
1844  * they are not used when processing image pixel values.
1845  *
1846  * While the input is an 'unsigned' value it must actually be the
1847  * correct bit value - 0..255 or 0..65535 as required.
1848  */
1849 PNG_INTERNAL_FUNCTION(png_uint_16,png_gamma_correct,(png_structrp png_ptr,
1850  unsigned int value, png_fixed_point gamma_value),PNG_EMPTY);
1851 PNG_INTERNAL_FUNCTION(png_uint_16,png_gamma_16bit_correct,(unsigned int value,
1852  png_fixed_point gamma_value),PNG_EMPTY);
1853 PNG_INTERNAL_FUNCTION(png_byte,png_gamma_8bit_correct,(unsigned int value,
1854  png_fixed_point gamma_value),PNG_EMPTY);
1855 PNG_INTERNAL_FUNCTION(void,png_destroy_gamma_table,(png_structrp png_ptr),
1856  PNG_EMPTY);
1857 PNG_INTERNAL_FUNCTION(void,png_build_gamma_table,(png_structrp png_ptr,
1858  int bit_depth),PNG_EMPTY);
1859 #endif
1860 
1861 /* SIMPLIFIED READ/WRITE SUPPORT */
1862 #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
1863  defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
1864 /* The internal structure that png_image::opaque points to. */
1865 typedef struct png_control
1866 {
1867  png_structp png_ptr;
1868  png_infop info_ptr;
1869  png_voidp error_buf; /* Always a jmp_buf at present. */
1870 
1871  png_const_bytep memory; /* Memory buffer. */
1872  png_size_t size; /* Size of the memory buffer. */
1873 
1874  unsigned int for_write :1; /* Otherwise it is a read structure */
1875  unsigned int owned_file :1; /* We own the file in io_ptr */
1876 } png_control;
1877 
1878 /* Return the pointer to the jmp_buf from a png_control: necessary because C
1879  * does not reveal the type of the elements of jmp_buf.
1880  */
1881 #ifdef __cplusplus
1882 # define png_control_jmp_buf(pc) (((jmp_buf*)((pc)->error_buf))[0])
1883 #else
1884 # define png_control_jmp_buf(pc) ((pc)->error_buf)
1885 #endif
1886 
1887 /* Utility to safely execute a piece of libpng code catching and logging any
1888  * errors that might occur. Returns true on success, false on failure (either
1889  * of the function or as a result of a png_error.)
1890  */
1891 PNG_INTERNAL_CALLBACK(void,png_safe_error,(png_structp png_ptr,
1892  png_const_charp error_message),PNG_NORETURN);
1893 
1894 #ifdef PNG_WARNINGS_SUPPORTED
1895 PNG_INTERNAL_CALLBACK(void,png_safe_warning,(png_structp png_ptr,
1896  png_const_charp warning_message),PNG_EMPTY);
1897 #else
1898 # define png_safe_warning 0/*dummy argument*/
1899 #endif
1900 
1901 PNG_INTERNAL_FUNCTION(int,png_safe_execute,(png_imagep image,
1902  int (*function)(png_voidp), png_voidp arg),PNG_EMPTY);
1903 
1904 /* Utility to log an error; this also cleans up the png_image; the function
1905  * always returns 0 (false).
1906  */
1907 PNG_INTERNAL_FUNCTION(int,png_image_error,(png_imagep image,
1908  png_const_charp error_message),PNG_EMPTY);
1909 
1910 #ifndef PNG_SIMPLIFIED_READ_SUPPORTED
1911 /* png_image_free is used by the write code but not exported */
1912 PNG_INTERNAL_FUNCTION(void, png_image_free, (png_imagep image), PNG_EMPTY);
1913 #endif /* !SIMPLIFIED_READ */
1914 
1915 #endif /* SIMPLIFIED READ/WRITE */
1916 
1917 /* These are initialization functions for hardware specific PNG filter
1918  * optimizations; list these here then select the appropriate one at compile
1919  * time using the macro PNG_FILTER_OPTIMIZATIONS. If the macro is not defined
1920  * the generic code is used.
1921  */
1922 #ifdef PNG_FILTER_OPTIMIZATIONS
1923 PNG_INTERNAL_FUNCTION(void, PNG_FILTER_OPTIMIZATIONS, (png_structp png_ptr,
1924  unsigned int bpp), PNG_EMPTY);
1925  /* Just declare the optimization that will be used */
1926 #else
1927  /* List *all* the possible optimizations here - this branch is required if
1928  * the builder of libpng passes the definition of PNG_FILTER_OPTIMIZATIONS in
1929  * CFLAGS in place of CPPFLAGS *and* uses symbol prefixing.
1930  */
1931 PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_neon,
1932  (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
1933 #endif
1934 
1935 /* Maintainer: Put new private prototypes here ^ */
1936 
1937 #include "pngdebug.h"
1938 
1939 #ifdef __cplusplus
1940 }
1941 #endif
1942 
1943 #endif /* PNG_VERSION_INFO_ONLY */
1944 #endif /* PNGPRIV_H */
png_row_info_struct
Definition: png.h:894
png_control
Definition: pngpriv.h:1865
png_struct_def
Definition: pngstruct.h:144
png_image
Definition: png.h:2807
png_info_def
Definition: pnginfo.h:56
png_text_struct
Definition: png.h:703
png_sPLT_struct
Definition: png.h:674
png_time_struct
Definition: png.h:741
png_color_struct
Definition: png.h:619
png_color_8_struct
Definition: png.h:641
png_color_16_struct
Definition: png.h:629
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