xref: /aosp_15_r20/external/libpng/pngpriv.h (revision a67afe4df73cf47866eedc69947994b8ff839aba)
1 
2 /* pngpriv.h - private declarations for use inside libpng
3  *
4  * Copyright (c) 2018-2024 Cosmin Truta
5  * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
6  * Copyright (c) 1996-1997 Andreas Dilger
7  * 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 #ifndef _POSIX_SOURCE
39 #  define _POSIX_SOURCE 1 /* Just the POSIX 1003.1 and C89 APIs */
40 #endif
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 the deprecated
124     * __ARM_NEON__, so we check both variants.
125     *
126     * To disable ARM_NEON optimizations entirely, and skip compiling the
127     * associated assembler code, pass --enable-arm-neon=no to configure
128     * or put -DPNG_ARM_NEON_OPT=0 in CPPFLAGS.
129     */
130 #  if (defined(__ARM_NEON__) || defined(__ARM_NEON)) && \
131    defined(PNG_ALIGNED_MEMORY_SUPPORTED)
132 #     define PNG_ARM_NEON_OPT 2
133 #  else
134 #     define PNG_ARM_NEON_OPT 0
135 #  endif
136 #endif
137 
138 #if PNG_ARM_NEON_OPT > 0
139    /* NEON optimizations are to be at least considered by libpng, so enable the
140     * callbacks to do this.
141     */
142 #  define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_neon
143 #  ifndef PNG_ARM_NEON_IMPLEMENTATION
144       /* Use the intrinsics code by default. */
145 #     define PNG_ARM_NEON_IMPLEMENTATION 1
146 #  endif
147 #else /* PNG_ARM_NEON_OPT == 0 */
148 #     define PNG_ARM_NEON_IMPLEMENTATION 0
149 #endif /* PNG_ARM_NEON_OPT > 0 */
150 
151 #ifndef PNG_MIPS_MSA_OPT
152 #  if defined(__mips_msa) && (__mips_isa_rev >= 5) && \
153    defined(PNG_ALIGNED_MEMORY_SUPPORTED)
154 #     define PNG_MIPS_MSA_OPT 2
155 #  else
156 #     define PNG_MIPS_MSA_OPT 0
157 #  endif
158 #endif
159 
160 #ifndef PNG_MIPS_MMI_OPT
161 #  ifdef PNG_MIPS_MMI
162 #    if defined(__mips_loongson_mmi) && (_MIPS_SIM == _ABI64) && \
163      defined(PNG_ALIGNED_MEMORY_SUPPORTED)
164 #       define PNG_MIPS_MMI_OPT 1
165 #    else
166 #       define PNG_MIPS_MMI_OPT 0
167 #    endif
168 #  else
169 #    define PNG_MIPS_MMI_OPT 0
170 #  endif
171 #endif
172 
173 #ifndef PNG_POWERPC_VSX_OPT
174 #  if defined(__PPC64__) && defined(__ALTIVEC__) && defined(__VSX__)
175 #     define PNG_POWERPC_VSX_OPT 2
176 #  else
177 #     define PNG_POWERPC_VSX_OPT 0
178 #  endif
179 #endif
180 
181 #ifndef PNG_LOONGARCH_LSX_OPT
182 #  if defined(__loongarch_sx)
183 #     define PNG_LOONGARCH_LSX_OPT 1
184 #  else
185 #     define PNG_LOONGARCH_LSX_OPT 0
186 #  endif
187 #endif
188 
189 #ifndef PNG_INTEL_SSE_OPT
190 #   ifdef PNG_INTEL_SSE
191       /* Only check for SSE if the build configuration has been modified to
192        * enable SSE optimizations.  This means that these optimizations will
193        * be off by default.  See contrib/intel for more details.
194        */
195 #      if defined(__SSE4_1__) || defined(__AVX__) || defined(__SSSE3__) || \
196        defined(__SSE2__) || defined(_M_X64) || defined(_M_AMD64) || \
197        (defined(_M_IX86_FP) && _M_IX86_FP >= 2)
198 #         define PNG_INTEL_SSE_OPT 1
199 #      else
200 #         define PNG_INTEL_SSE_OPT 0
201 #      endif
202 #   else
203 #      define PNG_INTEL_SSE_OPT 0
204 #   endif
205 #endif
206 
207 #if PNG_INTEL_SSE_OPT > 0
208 #   ifndef PNG_INTEL_SSE_IMPLEMENTATION
209 #      if defined(__SSE4_1__) || defined(__AVX__)
210           /* We are not actually using AVX, but checking for AVX is the best
211              way we can detect SSE4.1 and SSSE3 on MSVC.
212           */
213 #         define PNG_INTEL_SSE_IMPLEMENTATION 3
214 #      elif defined(__SSSE3__)
215 #         define PNG_INTEL_SSE_IMPLEMENTATION 2
216 #      elif defined(__SSE2__) || defined(_M_X64) || defined(_M_AMD64) || \
217        (defined(_M_IX86_FP) && _M_IX86_FP >= 2)
218 #         define PNG_INTEL_SSE_IMPLEMENTATION 1
219 #      else
220 #         define PNG_INTEL_SSE_IMPLEMENTATION 0
221 #      endif
222 #   endif
223 
224 #   if PNG_INTEL_SSE_IMPLEMENTATION > 0
225 #      define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_sse2
226 #   endif
227 #else
228 #   define PNG_INTEL_SSE_IMPLEMENTATION 0
229 #endif
230 
231 #if PNG_MIPS_MSA_OPT > 0
232 #  ifndef PNG_MIPS_MSA_IMPLEMENTATION
233 #     if defined(__mips_msa)
234 #        if defined(__clang__)
235 #        elif defined(__GNUC__)
236 #           if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 7)
237 #              define PNG_MIPS_MSA_IMPLEMENTATION 2
238 #           endif /* no GNUC support */
239 #        endif /* __GNUC__ */
240 #     else /* !defined __mips_msa */
241 #        define PNG_MIPS_MSA_IMPLEMENTATION 2
242 #     endif /* __mips_msa */
243 #  endif /* !PNG_MIPS_MSA_IMPLEMENTATION */
244 
245 #  ifndef PNG_MIPS_MSA_IMPLEMENTATION
246 #     define PNG_MIPS_MSA_IMPLEMENTATION 1
247 #     define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_mips
248 #  endif
249 #else
250 #  define PNG_MIPS_MSA_IMPLEMENTATION 0
251 #endif /* PNG_MIPS_MSA_OPT > 0 */
252 
253 #if PNG_MIPS_MMI_OPT > 0
254 #  ifndef PNG_MIPS_MMI_IMPLEMENTATION
255 #     if defined(__mips_loongson_mmi) && (_MIPS_SIM == _ABI64)
256 #        define PNG_MIPS_MMI_IMPLEMENTATION 2
257 #     else /* !defined __mips_loongson_mmi  || _MIPS_SIM != _ABI64 */
258 #        define PNG_MIPS_MMI_IMPLEMENTATION 0
259 #     endif /* __mips_loongson_mmi  && _MIPS_SIM == _ABI64 */
260 #  endif /* !PNG_MIPS_MMI_IMPLEMENTATION */
261 
262 #   if PNG_MIPS_MMI_IMPLEMENTATION > 0
263 #      define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_mips
264 #   endif
265 #else
266 #   define PNG_MIPS_MMI_IMPLEMENTATION 0
267 #endif /* PNG_MIPS_MMI_OPT > 0 */
268 
269 #if PNG_POWERPC_VSX_OPT > 0
270 #  define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_vsx
271 #  define PNG_POWERPC_VSX_IMPLEMENTATION 1
272 #else
273 #  define PNG_POWERPC_VSX_IMPLEMENTATION 0
274 #endif
275 
276 #if PNG_LOONGARCH_LSX_OPT > 0
277 #   define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_lsx
278 #   define PNG_LOONGARCH_LSX_IMPLEMENTATION 1
279 #else
280 #   define PNG_LOONGARCH_LSX_IMPLEMENTATION 0
281 #endif
282 
283 /* Is this a build of a DLL where compilation of the object modules requires
284  * different preprocessor settings to those required for a simple library?  If
285  * so PNG_BUILD_DLL must be set.
286  *
287  * If libpng is used inside a DLL but that DLL does not export the libpng APIs
288  * PNG_BUILD_DLL must not be set.  To avoid the code below kicking in build a
289  * static library of libpng then link the DLL against that.
290  */
291 #ifndef PNG_BUILD_DLL
292 #  ifdef DLL_EXPORT
293       /* This is set by libtool when files are compiled for a DLL; libtool
294        * always compiles twice, even on systems where it isn't necessary.  Set
295        * PNG_BUILD_DLL in case it is necessary:
296        */
297 #     define PNG_BUILD_DLL
298 #  else
299 #     ifdef _WINDLL
300          /* This is set by the Microsoft Visual Studio IDE in projects that
301           * build a DLL.  It can't easily be removed from those projects (it
302           * isn't visible in the Visual Studio UI) so it is a fairly reliable
303           * indication that PNG_IMPEXP needs to be set to the DLL export
304           * attributes.
305           */
306 #        define PNG_BUILD_DLL
307 #     else
308 #        ifdef __DLL__
309             /* This is set by the Borland C system when compiling for a DLL
310              * (as above.)
311              */
312 #           define PNG_BUILD_DLL
313 #        else
314             /* Add additional compiler cases here. */
315 #        endif
316 #     endif
317 #  endif
318 #endif /* Setting PNG_BUILD_DLL if required */
319 
320 /* See pngconf.h for more details: the builder of the library may set this on
321  * the command line to the right thing for the specific compilation system or it
322  * may be automagically set above (at present we know of no system where it does
323  * need to be set on the command line.)
324  *
325  * PNG_IMPEXP must be set here when building the library to prevent pngconf.h
326  * setting it to the "import" setting for a DLL build.
327  */
328 #ifndef PNG_IMPEXP
329 #  ifdef PNG_BUILD_DLL
330 #     define PNG_IMPEXP PNG_DLL_EXPORT
331 #  else
332       /* Not building a DLL, or the DLL doesn't require specific export
333        * definitions.
334        */
335 #     define PNG_IMPEXP
336 #  endif
337 #endif
338 
339 /* No warnings for private or deprecated functions in the build: */
340 #ifndef PNG_DEPRECATED
341 #  define PNG_DEPRECATED
342 #endif
343 #ifndef PNG_PRIVATE
344 #  define PNG_PRIVATE
345 #endif
346 
347 /* Symbol preprocessing support.
348  *
349  * To enable listing global, but internal, symbols the following macros should
350  * always be used to declare an extern data or function object in this file.
351  */
352 #ifndef PNG_INTERNAL_DATA
353 #  define PNG_INTERNAL_DATA(type, name, array) PNG_LINKAGE_DATA type name array
354 #endif
355 
356 #ifndef PNG_INTERNAL_FUNCTION
357 #  define PNG_INTERNAL_FUNCTION(type, name, args, attributes)\
358       PNG_LINKAGE_FUNCTION PNG_FUNCTION(type, name, args, PNG_EMPTY attributes)
359 #endif
360 
361 #ifndef PNG_INTERNAL_CALLBACK
362 #  define PNG_INTERNAL_CALLBACK(type, name, args, attributes)\
363       PNG_LINKAGE_CALLBACK PNG_FUNCTION(type, (PNGCBAPI name), args,\
364          PNG_EMPTY attributes)
365 #endif
366 
367 /* If floating or fixed point APIs are disabled they may still be compiled
368  * internally.  To handle this make sure they are declared as the appropriate
369  * internal extern function (otherwise the symbol prefixing stuff won't work and
370  * the functions will be used without definitions.)
371  *
372  * NOTE: although all the API functions are declared here they are not all
373  * actually built!  Because the declarations are still made it is necessary to
374  * fake out types that they depend on.
375  */
376 #ifndef PNG_FP_EXPORT
377 #  ifndef PNG_FLOATING_POINT_SUPPORTED
378 #     define PNG_FP_EXPORT(ordinal, type, name, args)\
379          PNG_INTERNAL_FUNCTION(type, name, args, PNG_EMPTY);
380 #     ifndef PNG_VERSION_INFO_ONLY
381          typedef struct png_incomplete png_double;
382          typedef png_double*           png_doublep;
383          typedef const png_double*     png_const_doublep;
384          typedef png_double**          png_doublepp;
385 #     endif
386 #  endif
387 #endif
388 #ifndef PNG_FIXED_EXPORT
389 #  ifndef PNG_FIXED_POINT_SUPPORTED
390 #     define PNG_FIXED_EXPORT(ordinal, type, name, args)\
391          PNG_INTERNAL_FUNCTION(type, name, args, PNG_EMPTY);
392 #  endif
393 #endif
394 
395 #include "png.h"
396 
397 /* pngconf.h does not set PNG_DLL_EXPORT unless it is required, so: */
398 #ifndef PNG_DLL_EXPORT
399 #  define PNG_DLL_EXPORT
400 #endif
401 
402 /* This is a global switch to set the compilation for an installed system
403  * (a release build).  It can be set for testing debug builds to ensure that
404  * they will compile when the build type is switched to RC or STABLE, the
405  * default is just to use PNG_LIBPNG_BUILD_BASE_TYPE.  Set this in CPPFLAGS
406  * with either:
407  *
408  *   -DPNG_RELEASE_BUILD Turns on the release compile path
409  *   -DPNG_RELEASE_BUILD=0 Turns it off
410  * or in your pngusr.h with
411  *   #define PNG_RELEASE_BUILD=1 Turns on the release compile path
412  *   #define PNG_RELEASE_BUILD=0 Turns it off
413  */
414 #ifndef PNG_RELEASE_BUILD
415 #  define PNG_RELEASE_BUILD (PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC)
416 #endif
417 
418 /* SECURITY and SAFETY:
419  *
420  * libpng is built with support for internal limits on image dimensions and
421  * memory usage.  These are documented in scripts/pnglibconf.dfa of the
422  * source and recorded in the machine generated header file pnglibconf.h.
423  */
424 
425 /* If you are running on a machine where you cannot allocate more
426  * than 64K of memory at once, uncomment this.  While libpng will not
427  * normally need that much memory in a chunk (unless you load up a very
428  * large file), zlib needs to know how big of a chunk it can use, and
429  * libpng thus makes sure to check any memory allocation to verify it
430  * will fit into memory.
431  *
432  * zlib provides 'MAXSEG_64K' which, if defined, indicates the
433  * same limit and pngconf.h (already included) sets the limit
434  * if certain operating systems are detected.
435  */
436 #if defined(MAXSEG_64K) && !defined(PNG_MAX_MALLOC_64K)
437 #  define PNG_MAX_MALLOC_64K
438 #endif
439 
440 #ifndef PNG_UNUSED
441 /* Unused formal parameter warnings are silenced using the following macro
442  * which is expected to have no bad effects on performance (optimizing
443  * compilers will probably remove it entirely).  Note that if you replace
444  * it with something other than whitespace, you must include the terminating
445  * semicolon.
446  */
447 #  define PNG_UNUSED(param) (void)param;
448 #endif
449 
450 /* Just a little check that someone hasn't tried to define something
451  * contradictory.
452  */
453 #if (PNG_ZBUF_SIZE > 65536L) && defined(PNG_MAX_MALLOC_64K)
454 #  undef PNG_ZBUF_SIZE
455 #  define PNG_ZBUF_SIZE 65536L
456 #endif
457 
458 /* If warnings or errors are turned off the code is disabled or redirected here.
459  * From 1.5.4 functions have been added to allow very limited formatting of
460  * error and warning messages - this code will also be disabled here.
461  */
462 #ifdef PNG_WARNINGS_SUPPORTED
463 #  define PNG_WARNING_PARAMETERS(p) png_warning_parameters p;
464 #else
465 #  define png_warning_parameter(p,number,string) ((void)0)
466 #  define png_warning_parameter_unsigned(p,number,format,value) ((void)0)
467 #  define png_warning_parameter_signed(p,number,format,value) ((void)0)
468 #  define png_formatted_warning(pp,p,message) ((void)(pp))
469 #  define PNG_WARNING_PARAMETERS(p)
470 #endif
471 #ifndef PNG_ERROR_TEXT_SUPPORTED
472 #  define png_fixed_error(s1,s2) png_err(s1)
473 #endif
474 
475 /* Some fixed point APIs are still required even if not exported because
476  * they get used by the corresponding floating point APIs.  This magic
477  * deals with this:
478  */
479 #ifdef PNG_FIXED_POINT_SUPPORTED
480 #  define PNGFAPI PNGAPI
481 #else
482 #  define PNGFAPI /* PRIVATE */
483 #endif
484 
485 #ifndef PNG_VERSION_INFO_ONLY
486 /* Other defines specific to compilers can go here.  Try to keep
487  * them inside an appropriate ifdef/endif pair for portability.
488  */
489 
490 /* C allows up-casts from (void*) to any pointer and (const void*) to any
491  * pointer to a const object.  C++ regards this as a type error and requires an
492  * explicit, static, cast and provides the static_cast<> rune to ensure that
493  * const is not cast away.
494  */
495 #ifdef __cplusplus
496 #  define png_voidcast(type, value) static_cast<type>(value)
497 #  define png_constcast(type, value) const_cast<type>(value)
498 #  define png_aligncast(type, value) \
499    static_cast<type>(static_cast<void*>(value))
500 #  define png_aligncastconst(type, value) \
501    static_cast<type>(static_cast<const void*>(value))
502 #else
503 #  define png_voidcast(type, value) (value)
504 #  define png_constcast(type, value) ((type)(void*)(const void*)(value))
505 #  define png_aligncast(type, value) ((void*)(value))
506 #  define png_aligncastconst(type, value) ((const void*)(value))
507 #endif /* __cplusplus */
508 
509 #if defined(PNG_FLOATING_POINT_SUPPORTED) ||\
510     defined(PNG_FLOATING_ARITHMETIC_SUPPORTED)
511    /* png.c requires the following ANSI-C constants if the conversion of
512     * floating point to ASCII is implemented therein:
513     *
514     *  DBL_DIG  Maximum number of decimal digits (can be set to any constant)
515     *  DBL_MIN  Smallest normalized fp number (can be set to an arbitrary value)
516     *  DBL_MAX  Maximum floating point number (can be set to an arbitrary value)
517     */
518 #  include <float.h>
519 
520 #  include <math.h>
521 
522 #  if defined(_AMIGA) && defined(__SASC) && defined(_M68881)
523    /* Amiga SAS/C: We must include builtin FPU functions when compiling using
524     * MATH=68881
525     */
526 #    include <m68881.h>
527 #  endif
528 #endif
529 
530 /* This provides the non-ANSI (far) memory allocation routines. */
531 #if defined(__TURBOC__) && defined(__MSDOS__)
532 #  include <mem.h>
533 #  include <alloc.h>
534 #endif
535 
536 #if defined(_WIN32) || defined(__WIN32__) || defined(__NT__)
537 #  include <windows.h>
538 #endif
539 #endif /* PNG_VERSION_INFO_ONLY */
540 
541 /* Moved here around 1.5.0beta36 from pngconf.h */
542 /* Users may want to use these so they are not private.  Any library
543  * functions that are passed far data must be model-independent.
544  */
545 
546 /* Platform-independent functions */
547 #ifndef PNG_ABORT
548 #  define PNG_ABORT() abort()
549 #endif
550 
551 /* These macros may need to be architecture dependent. */
552 #define PNG_ALIGN_NONE      0 /* do not use data alignment */
553 #define PNG_ALIGN_ALWAYS    1 /* assume unaligned accesses are OK */
554 #ifdef offsetof
555 #  define PNG_ALIGN_OFFSET  2 /* use offsetof to determine alignment */
556 #else
557 #  define PNG_ALIGN_OFFSET -1 /* prevent the use of this */
558 #endif
559 #define PNG_ALIGN_SIZE      3 /* use sizeof to determine alignment */
560 
561 #ifndef PNG_ALIGN_TYPE
562    /* Default to using aligned access optimizations and requiring alignment to a
563     * multiple of the data type size.  Override in a compiler specific fashion
564     * if necessary by inserting tests here:
565     */
566 #  define PNG_ALIGN_TYPE PNG_ALIGN_SIZE
567 #endif
568 
569 #if PNG_ALIGN_TYPE == PNG_ALIGN_SIZE
570    /* This is used because in some compiler implementations non-aligned
571     * structure members are supported, so the offsetof approach below fails.
572     * Set PNG_ALIGN_SIZE=0 for compiler combinations where unaligned access
573     * is good for performance.  Do not do this unless you have tested the
574     * result and understand it.
575     */
576 #  define png_alignof(type) (sizeof(type))
577 #else
578 #  if PNG_ALIGN_TYPE == PNG_ALIGN_OFFSET
579 #    define png_alignof(type) offsetof(struct{char c; type t;}, t)
580 #  else
581 #    if PNG_ALIGN_TYPE == PNG_ALIGN_ALWAYS
582 #      define png_alignof(type) 1
583 #    endif
584      /* Else leave png_alignof undefined to prevent use thereof */
585 #  endif
586 #endif
587 
588 /* This implicitly assumes alignment is always a multiple of 2. */
589 #ifdef png_alignof
590 #  define png_isaligned(ptr, type) \
591    (((type)(size_t)((const void*)(ptr)) & (type)(png_alignof(type)-1)) == 0)
592 #else
593 #  define png_isaligned(ptr, type) 0
594 #endif
595 
596 /* End of memory model/platform independent support */
597 /* End of 1.5.0beta36 move from pngconf.h */
598 
599 /* CONSTANTS and UTILITY MACROS
600  * These are used internally by libpng and not exposed in the API
601  */
602 
603 /* Various modes of operation.  Note that after an init, mode is set to
604  * zero automatically when the structure is created.  Three of these
605  * are defined in png.h because they need to be visible to applications
606  * that call png_set_unknown_chunk().
607  */
608 /* #define PNG_HAVE_IHDR            0x01U (defined in png.h) */
609 /* #define PNG_HAVE_PLTE            0x02U (defined in png.h) */
610 #define PNG_HAVE_IDAT               0x04U
611 /* #define PNG_AFTER_IDAT           0x08U (defined in png.h) */
612 #define PNG_HAVE_IEND               0x10U
613                    /*               0x20U (unused) */
614                    /*               0x40U (unused) */
615                    /*               0x80U (unused) */
616 #define PNG_HAVE_CHUNK_HEADER      0x100U
617 #define PNG_WROTE_tIME             0x200U
618 #define PNG_WROTE_INFO_BEFORE_PLTE 0x400U
619 #define PNG_BACKGROUND_IS_GRAY     0x800U
620 #define PNG_HAVE_PNG_SIGNATURE    0x1000U
621 #define PNG_HAVE_CHUNK_AFTER_IDAT 0x2000U /* Have another chunk after IDAT */
622 #define PNG_WROTE_eXIf            0x4000U
623 #define PNG_IS_READ_STRUCT        0x8000U /* Else is a write struct */
624 
625 /* Flags for the transformations the PNG library does on the image data */
626 #define PNG_BGR                 0x0001U
627 #define PNG_INTERLACE           0x0002U
628 #define PNG_PACK                0x0004U
629 #define PNG_SHIFT               0x0008U
630 #define PNG_SWAP_BYTES          0x0010U
631 #define PNG_INVERT_MONO         0x0020U
632 #define PNG_QUANTIZE            0x0040U
633 #define PNG_COMPOSE             0x0080U    /* Was PNG_BACKGROUND */
634 #define PNG_BACKGROUND_EXPAND   0x0100U
635 #define PNG_EXPAND_16           0x0200U    /* Added to libpng 1.5.2 */
636 #define PNG_16_TO_8             0x0400U    /* Becomes 'chop' in 1.5.4 */
637 #define PNG_RGBA                0x0800U
638 #define PNG_EXPAND              0x1000U
639 #define PNG_GAMMA               0x2000U
640 #define PNG_GRAY_TO_RGB         0x4000U
641 #define PNG_FILLER              0x8000U
642 #define PNG_PACKSWAP           0x10000U
643 #define PNG_SWAP_ALPHA         0x20000U
644 #define PNG_STRIP_ALPHA        0x40000U
645 #define PNG_INVERT_ALPHA       0x80000U
646 #define PNG_USER_TRANSFORM    0x100000U
647 #define PNG_RGB_TO_GRAY_ERR   0x200000U
648 #define PNG_RGB_TO_GRAY_WARN  0x400000U
649 #define PNG_RGB_TO_GRAY       0x600000U /* two bits, RGB_TO_GRAY_ERR|WARN */
650 #define PNG_ENCODE_ALPHA      0x800000U /* Added to libpng-1.5.4 */
651 #define PNG_ADD_ALPHA        0x1000000U /* Added to libpng-1.2.7 */
652 #define PNG_EXPAND_tRNS      0x2000000U /* Added to libpng-1.2.9 */
653 #define PNG_SCALE_16_TO_8    0x4000000U /* Added to libpng-1.5.4 */
654                        /*    0x8000000U unused */
655                        /*   0x10000000U unused */
656                        /*   0x20000000U unused */
657                        /*   0x40000000U unused */
658 /* Flags for png_create_struct */
659 #define PNG_STRUCT_PNG   0x0001U
660 #define PNG_STRUCT_INFO  0x0002U
661 
662 /* Flags for the png_ptr->flags rather than declaring a byte for each one */
663 #define PNG_FLAG_ZLIB_CUSTOM_STRATEGY     0x0001U
664 #define PNG_FLAG_ZSTREAM_INITIALIZED      0x0002U /* Added to libpng-1.6.0 */
665                                   /*      0x0004U    unused */
666 #define PNG_FLAG_ZSTREAM_ENDED            0x0008U /* Added to libpng-1.6.0 */
667                                   /*      0x0010U    unused */
668                                   /*      0x0020U    unused */
669 #define PNG_FLAG_ROW_INIT                 0x0040U
670 #define PNG_FLAG_FILLER_AFTER             0x0080U
671 #define PNG_FLAG_CRC_ANCILLARY_USE        0x0100U
672 #define PNG_FLAG_CRC_ANCILLARY_NOWARN     0x0200U
673 #define PNG_FLAG_CRC_CRITICAL_USE         0x0400U
674 #define PNG_FLAG_CRC_CRITICAL_IGNORE      0x0800U
675 #define PNG_FLAG_ASSUME_sRGB              0x1000U /* Added to libpng-1.5.4 */
676 #define PNG_FLAG_OPTIMIZE_ALPHA           0x2000U /* Added to libpng-1.5.4 */
677 #define PNG_FLAG_DETECT_UNINITIALIZED     0x4000U /* Added to libpng-1.5.4 */
678 /* #define PNG_FLAG_KEEP_UNKNOWN_CHUNKS      0x8000U */
679 /* #define PNG_FLAG_KEEP_UNSAFE_CHUNKS      0x10000U */
680 #define PNG_FLAG_LIBRARY_MISMATCH        0x20000U
681 #define PNG_FLAG_STRIP_ERROR_NUMBERS     0x40000U
682 #define PNG_FLAG_STRIP_ERROR_TEXT        0x80000U
683 #define PNG_FLAG_BENIGN_ERRORS_WARN     0x100000U /* Added to libpng-1.4.0 */
684 #define PNG_FLAG_APP_WARNINGS_WARN      0x200000U /* Added to libpng-1.6.0 */
685 #define PNG_FLAG_APP_ERRORS_WARN        0x400000U /* Added to libpng-1.6.0 */
686                                   /*    0x800000U    unused */
687                                   /*   0x1000000U    unused */
688                                   /*   0x2000000U    unused */
689                                   /*   0x4000000U    unused */
690                                   /*   0x8000000U    unused */
691                                   /*  0x10000000U    unused */
692                                   /*  0x20000000U    unused */
693                                   /*  0x40000000U    unused */
694 
695 #define PNG_FLAG_CRC_ANCILLARY_MASK (PNG_FLAG_CRC_ANCILLARY_USE | \
696                                      PNG_FLAG_CRC_ANCILLARY_NOWARN)
697 
698 #define PNG_FLAG_CRC_CRITICAL_MASK  (PNG_FLAG_CRC_CRITICAL_USE | \
699                                      PNG_FLAG_CRC_CRITICAL_IGNORE)
700 
701 #define PNG_FLAG_CRC_MASK           (PNG_FLAG_CRC_ANCILLARY_MASK | \
702                                      PNG_FLAG_CRC_CRITICAL_MASK)
703 
704 /* Save typing and make code easier to understand */
705 
706 #define PNG_COLOR_DIST(c1, c2) (abs((int)((c1).red) - (int)((c2).red)) + \
707    abs((int)((c1).green) - (int)((c2).green)) + \
708    abs((int)((c1).blue) - (int)((c2).blue)))
709 
710 /* Added to libpng-1.6.0: scale a 16-bit value in the range 0..65535 to 0..255
711  * by dividing by 257 *with rounding*.  This macro is exact for the given range.
712  * See the discourse in pngrtran.c png_do_scale_16_to_8.  The values in the
713  * macro were established by experiment (modifying the added value).  The macro
714  * has a second variant that takes a value already scaled by 255 and divides by
715  * 65535 - this has a maximum error of .502.  Over the range 0..65535*65535 it
716  * only gives off-by-one errors and only for 0.5% (1 in 200) of the values.
717  */
718 #define PNG_DIV65535(v24) (((v24) + 32895) >> 16)
719 #define PNG_DIV257(v16) PNG_DIV65535((png_uint_32)(v16) * 255)
720 
721 /* Added to libpng-1.2.6 JB */
722 #define PNG_ROWBYTES(pixel_bits, width) \
723     ((pixel_bits) >= 8 ? \
724     ((size_t)(width) * (((size_t)(pixel_bits)) >> 3)) : \
725     (( ((size_t)(width) * ((size_t)(pixel_bits))) + 7) >> 3) )
726 
727 /* This returns the number of trailing bits in the last byte of a row, 0 if the
728  * last byte is completely full of pixels.  It is, in principle, (pixel_bits x
729  * width) % 8, but that would overflow for large 'width'.  The second macro is
730  * the same except that it returns the number of unused bits in the last byte;
731  * (8-TRAILBITS), but 0 when TRAILBITS is 0.
732  *
733  * NOTE: these macros are intended to be self-evidently correct and never
734  * overflow on the assumption that pixel_bits is in the range 0..255.  The
735  * arguments are evaluated only once and they can be signed (e.g. as a result of
736  * the integral promotions).  The result of the expression always has type
737  * (png_uint_32), however the compiler always knows it is in the range 0..7.
738  */
739 #define PNG_TRAILBITS(pixel_bits, width) \
740     (((pixel_bits) * ((width) % (png_uint_32)8)) % 8)
741 
742 #define PNG_PADBITS(pixel_bits, width) \
743     ((8 - PNG_TRAILBITS(pixel_bits, width)) % 8)
744 
745 /* PNG_OUT_OF_RANGE returns true if value is outside the range
746  * ideal-delta..ideal+delta.  Each argument is evaluated twice.
747  * "ideal" and "delta" should be constants, normally simple
748  * integers, "value" a variable. Added to libpng-1.2.6 JB
749  */
750 #define PNG_OUT_OF_RANGE(value, ideal, delta) \
751    ( (value) < (ideal)-(delta) || (value) > (ideal)+(delta) )
752 
753 /* Conversions between fixed and floating point, only defined if
754  * required (to make sure the code doesn't accidentally use float
755  * when it is supposedly disabled.)
756  */
757 #ifdef PNG_FLOATING_POINT_SUPPORTED
758 /* The floating point conversion can't overflow, though it can and
759  * does lose accuracy relative to the original fixed point value.
760  * In practice this doesn't matter because png_fixed_point only
761  * stores numbers with very low precision.  The png_ptr and s
762  * arguments are unused by default but are there in case error
763  * checking becomes a requirement.
764  */
765 #define png_float(png_ptr, fixed, s) (.00001 * (fixed))
766 
767 /* The fixed point conversion performs range checking and evaluates
768  * its argument multiple times, so must be used with care.  The
769  * range checking uses the PNG specification values for a signed
770  * 32-bit fixed point value except that the values are deliberately
771  * rounded-to-zero to an integral value - 21474 (21474.83 is roughly
772  * (2^31-1) * 100000). 's' is a string that describes the value being
773  * converted.
774  *
775  * NOTE: this macro will raise a png_error if the range check fails,
776  * therefore it is normally only appropriate to use this on values
777  * that come from API calls or other sources where an out of range
778  * error indicates a programming error, not a data error!
779  *
780  * NOTE: by default this is off - the macro is not used - because the
781  * function call saves a lot of code.
782  */
783 #ifdef PNG_FIXED_POINT_MACRO_SUPPORTED
784 #define png_fixed(png_ptr, fp, s) ((fp) <= 21474 && (fp) >= -21474 ?\
785     ((png_fixed_point)(100000 * (fp))) : (png_fixed_error(png_ptr, s),0))
786 #endif
787 /* else the corresponding function is defined below, inside the scope of the
788  * cplusplus test.
789  */
790 #endif
791 
792 /* Constants for known chunk types.  If you need to add a chunk, define the name
793  * here.  For historical reasons these constants have the form png_<name>; i.e.
794  * the prefix is lower case.  Please use decimal values as the parameters to
795  * match the ISO PNG specification and to avoid relying on the C locale
796  * interpretation of character values.
797  *
798  * Prior to 1.5.6 these constants were strings, as of 1.5.6 png_uint_32 values
799  * are computed and a new macro (PNG_STRING_FROM_CHUNK) added to allow a string
800  * to be generated if required.
801  *
802  * PNG_32b correctly produces a value shifted by up to 24 bits, even on
803  * architectures where (int) is only 16 bits.
804  */
805 #define PNG_32b(b,s) ((png_uint_32)(b) << (s))
806 #define PNG_U32(b1,b2,b3,b4) \
807    (PNG_32b(b1,24) | PNG_32b(b2,16) | PNG_32b(b3,8) | PNG_32b(b4,0))
808 
809 /* Constants for known chunk types.
810  *
811  * MAINTAINERS: If you need to add a chunk, define the name here.
812  * For historical reasons these constants have the form png_<name>; i.e.
813  * the prefix is lower case.  Please use decimal values as the parameters to
814  * match the ISO PNG specification and to avoid relying on the C locale
815  * interpretation of character values.  Please keep the list sorted.
816  *
817  * Notice that PNG_U32 is used to define a 32-bit value for the 4 byte chunk
818  * type.  In fact the specification does not express chunk types this way,
819  * however using a 32-bit value means that the chunk type can be read from the
820  * stream using exactly the same code as used for a 32-bit unsigned value and
821  * can be examined far more efficiently (using one arithmetic compare).
822  *
823  * Prior to 1.5.6 the chunk type constants were expressed as C strings.  The
824  * libpng API still uses strings for 'unknown' chunks and a macro,
825  * PNG_STRING_FROM_CHUNK, allows a string to be generated if required.  Notice
826  * that for portable code numeric values must still be used; the string "IHDR"
827  * is not portable and neither is PNG_U32('I', 'H', 'D', 'R').
828  *
829  * In 1.7.0 the definitions will be made public in png.h to avoid having to
830  * duplicate the same definitions in application code.
831  */
832 #define png_IDAT PNG_U32( 73,  68,  65,  84)
833 #define png_IEND PNG_U32( 73,  69,  78,  68)
834 #define png_IHDR PNG_U32( 73,  72,  68,  82)
835 #define png_PLTE PNG_U32( 80,  76,  84,  69)
836 #define png_bKGD PNG_U32( 98,  75,  71,  68)
837 #define png_cHRM PNG_U32( 99,  72,  82,  77)
838 #define png_eXIf PNG_U32(101,  88,  73, 102) /* registered July 2017 */
839 #define png_fRAc PNG_U32(102,  82,  65,  99) /* registered, not defined */
840 #define png_gAMA PNG_U32(103,  65,  77,  65)
841 #define png_gIFg PNG_U32(103,  73,  70, 103)
842 #define png_gIFt PNG_U32(103,  73,  70, 116) /* deprecated */
843 #define png_gIFx PNG_U32(103,  73,  70, 120)
844 #define png_hIST PNG_U32(104,  73,  83,  84)
845 #define png_iCCP PNG_U32(105,  67,  67,  80)
846 #define png_iTXt PNG_U32(105,  84,  88, 116)
847 #define png_oFFs PNG_U32(111,  70,  70, 115)
848 #define png_pCAL PNG_U32(112,  67,  65,  76)
849 #define png_pHYs PNG_U32(112,  72,  89, 115)
850 #define png_sBIT PNG_U32(115,  66,  73,  84)
851 #define png_sCAL PNG_U32(115,  67,  65,  76)
852 #define png_sPLT PNG_U32(115,  80,  76,  84)
853 #define png_sRGB PNG_U32(115,  82,  71,  66)
854 #define png_sTER PNG_U32(115,  84,  69,  82)
855 #define png_tEXt PNG_U32(116,  69,  88, 116)
856 #define png_tIME PNG_U32(116,  73,  77,  69)
857 #define png_tRNS PNG_U32(116,  82,  78,  83)
858 #define png_zTXt PNG_U32(122,  84,  88, 116)
859 
860 /* The following will work on (signed char*) strings, whereas the get_uint_32
861  * macro will fail on top-bit-set values because of the sign extension.
862  */
863 #define PNG_CHUNK_FROM_STRING(s)\
864    PNG_U32(0xff & (s)[0], 0xff & (s)[1], 0xff & (s)[2], 0xff & (s)[3])
865 
866 /* This uses (char), not (png_byte) to avoid warnings on systems where (char) is
867  * signed and the argument is a (char[])  This macro will fail miserably on
868  * systems where (char) is more than 8 bits.
869  */
870 #define PNG_STRING_FROM_CHUNK(s,c)\
871    (void)(((char*)(s))[0]=(char)(((c)>>24) & 0xff), \
872    ((char*)(s))[1]=(char)(((c)>>16) & 0xff),\
873    ((char*)(s))[2]=(char)(((c)>>8) & 0xff), \
874    ((char*)(s))[3]=(char)((c & 0xff)))
875 
876 /* Do the same but terminate with a null character. */
877 #define PNG_CSTRING_FROM_CHUNK(s,c)\
878    (void)(PNG_STRING_FROM_CHUNK(s,c), ((char*)(s))[4] = 0)
879 
880 /* Test on flag values as defined in the spec (section 5.4): */
881 #define PNG_CHUNK_ANCILLARY(c)   (1 & ((c) >> 29))
882 #define PNG_CHUNK_CRITICAL(c)     (!PNG_CHUNK_ANCILLARY(c))
883 #define PNG_CHUNK_PRIVATE(c)      (1 & ((c) >> 21))
884 #define PNG_CHUNK_RESERVED(c)     (1 & ((c) >> 13))
885 #define PNG_CHUNK_SAFE_TO_COPY(c) (1 & ((c) >>  5))
886 
887 /* Gamma values (new at libpng-1.5.4): */
888 #define PNG_GAMMA_MAC_OLD 151724  /* Assume '1.8' is really 2.2/1.45! */
889 #define PNG_GAMMA_MAC_INVERSE 65909
890 #define PNG_GAMMA_sRGB_INVERSE 45455
891 
892 /* Almost everything below is C specific; the #defines above can be used in
893  * non-C code (so long as it is C-preprocessed) the rest of this stuff cannot.
894  */
895 #ifndef PNG_VERSION_INFO_ONLY
896 
897 #include "pngstruct.h"
898 #include "pnginfo.h"
899 
900 /* Validate the include paths - the include path used to generate pnglibconf.h
901  * must match that used in the build, or we must be using pnglibconf.h.prebuilt:
902  */
903 #if PNG_ZLIB_VERNUM != 0 && PNG_ZLIB_VERNUM != ZLIB_VERNUM
904 #  error ZLIB_VERNUM != PNG_ZLIB_VERNUM \
905       "-I (include path) error: see the notes in pngpriv.h"
906    /* This means that when pnglibconf.h was built the copy of zlib.h that it
907     * used is not the same as the one being used here.  Because the build of
908     * libpng makes decisions to use inflateInit2 and inflateReset2 based on the
909     * zlib version number and because this affects handling of certain broken
910     * PNG files the -I directives must match.
911     *
912     * The most likely explanation is that you passed a -I in CFLAGS. This will
913     * not work; all the preprocessor directives and in particular all the -I
914     * directives must be in CPPFLAGS.
915     */
916 #endif
917 
918 /* This is used for 16-bit gamma tables -- only the top level pointers are
919  * const; this could be changed:
920  */
921 typedef const png_uint_16p * png_const_uint_16pp;
922 
923 /* Added to libpng-1.5.7: sRGB conversion tables */
924 #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
925    defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
926 #ifdef PNG_SIMPLIFIED_READ_SUPPORTED
927 PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_table, [256]);
928    /* Convert from an sRGB encoded value 0..255 to a 16-bit linear value,
929     * 0..65535.  This table gives the closest 16-bit answers (no errors).
930     */
931 #endif
932 
933 PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_base, [512]);
934 PNG_INTERNAL_DATA(const png_byte, png_sRGB_delta, [512]);
935 
936 #define PNG_sRGB_FROM_LINEAR(linear) \
937   ((png_byte)(0xff & ((png_sRGB_base[(linear)>>15] \
938    + ((((linear) & 0x7fff)*png_sRGB_delta[(linear)>>15])>>12)) >> 8)))
939    /* Given a value 'linear' in the range 0..255*65535 calculate the 8-bit sRGB
940     * encoded value with maximum error 0.646365.  Note that the input is not a
941     * 16-bit value; it has been multiplied by 255! */
942 #endif /* SIMPLIFIED_READ/WRITE */
943 
944 
945 /* Inhibit C++ name-mangling for libpng functions but not for system calls. */
946 #ifdef __cplusplus
947 extern "C" {
948 #endif /* __cplusplus */
949 
950 /* Internal functions; these are not exported from a DLL however because they
951  * are used within several of the C source files they have to be C extern.
952  *
953  * All of these functions must be declared with PNG_INTERNAL_FUNCTION.
954  */
955 
956 /* Zlib support */
957 #define PNG_UNEXPECTED_ZLIB_RETURN (-7)
958 PNG_INTERNAL_FUNCTION(void, png_zstream_error,(png_structrp png_ptr, int ret),
959    PNG_EMPTY);
960    /* Used by the zlib handling functions to ensure that z_stream::msg is always
961     * set before they return.
962     */
963 
964 #ifdef PNG_WRITE_SUPPORTED
965 PNG_INTERNAL_FUNCTION(void,png_free_buffer_list,(png_structrp png_ptr,
966    png_compression_bufferp *list),PNG_EMPTY);
967    /* Free the buffer list used by the compressed write code. */
968 #endif
969 
970 #if defined(PNG_FLOATING_POINT_SUPPORTED) && \
971    !defined(PNG_FIXED_POINT_MACRO_SUPPORTED) && \
972    (defined(PNG_gAMA_SUPPORTED) || defined(PNG_cHRM_SUPPORTED) || \
973    defined(PNG_sCAL_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) || \
974    defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)) || \
975    (defined(PNG_sCAL_SUPPORTED) && \
976    defined(PNG_FLOATING_ARITHMETIC_SUPPORTED))
977 PNG_INTERNAL_FUNCTION(png_fixed_point,png_fixed,(png_const_structrp png_ptr,
978    double fp, png_const_charp text),PNG_EMPTY);
979 #endif
980 
981 /* Check the user version string for compatibility, returns false if the version
982  * numbers aren't compatible.
983  */
984 PNG_INTERNAL_FUNCTION(int,png_user_version_check,(png_structrp png_ptr,
985    png_const_charp user_png_ver),PNG_EMPTY);
986 
987 /* Internal base allocator - no messages, NULL on failure to allocate.  This
988  * does, however, call the application provided allocator and that could call
989  * png_error (although that would be a bug in the application implementation.)
990  */
991 PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_base,(png_const_structrp png_ptr,
992    png_alloc_size_t size),PNG_ALLOCATED);
993 
994 #if defined(PNG_TEXT_SUPPORTED) || defined(PNG_sPLT_SUPPORTED) ||\
995    defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED)
996 /* Internal array allocator, outputs no error or warning messages on failure,
997  * just returns NULL.
998  */
999 PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_array,(png_const_structrp png_ptr,
1000    int nelements, size_t element_size),PNG_ALLOCATED);
1001 
1002 /* The same but an existing array is extended by add_elements.  This function
1003  * also memsets the new elements to 0 and copies the old elements.  The old
1004  * array is not freed or altered.
1005  */
1006 PNG_INTERNAL_FUNCTION(png_voidp,png_realloc_array,(png_const_structrp png_ptr,
1007    png_const_voidp array, int old_elements, int add_elements,
1008    size_t element_size),PNG_ALLOCATED);
1009 #endif /* text, sPLT or unknown chunks */
1010 
1011 /* Magic to create a struct when there is no struct to call the user supplied
1012  * memory allocators.  Because error handling has not been set up the memory
1013  * handlers can't safely call png_error, but this is an obscure and undocumented
1014  * restriction so libpng has to assume that the 'free' handler, at least, might
1015  * call png_error.
1016  */
1017 PNG_INTERNAL_FUNCTION(png_structp,png_create_png_struct,
1018    (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
1019     png_error_ptr warn_fn, png_voidp mem_ptr, png_malloc_ptr malloc_fn,
1020     png_free_ptr free_fn),PNG_ALLOCATED);
1021 
1022 /* Free memory from internal libpng struct */
1023 PNG_INTERNAL_FUNCTION(void,png_destroy_png_struct,(png_structrp png_ptr),
1024    PNG_EMPTY);
1025 
1026 /* Free an allocated jmp_buf (always succeeds) */
1027 PNG_INTERNAL_FUNCTION(void,png_free_jmpbuf,(png_structrp png_ptr),PNG_EMPTY);
1028 
1029 /* Function to allocate memory for zlib.  PNGAPI is disallowed. */
1030 PNG_INTERNAL_FUNCTION(voidpf,png_zalloc,(voidpf png_ptr, uInt items, uInt size),
1031    PNG_ALLOCATED);
1032 
1033 /* Function to free memory for zlib.  PNGAPI is disallowed. */
1034 PNG_INTERNAL_FUNCTION(void,png_zfree,(voidpf png_ptr, voidpf ptr),PNG_EMPTY);
1035 
1036 /* Next four functions are used internally as callbacks.  PNGCBAPI is required
1037  * but not PNG_EXPORT.  PNGAPI added at libpng version 1.2.3, changed to
1038  * PNGCBAPI at 1.5.0
1039  */
1040 
1041 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_read_data,(png_structp png_ptr,
1042     png_bytep data, size_t length),PNG_EMPTY);
1043 
1044 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1045 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_push_fill_buffer,(png_structp png_ptr,
1046     png_bytep buffer, size_t length),PNG_EMPTY);
1047 #endif
1048 
1049 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_write_data,(png_structp png_ptr,
1050     png_bytep data, size_t length),PNG_EMPTY);
1051 
1052 #ifdef PNG_WRITE_FLUSH_SUPPORTED
1053 #  ifdef PNG_STDIO_SUPPORTED
1054 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_flush,(png_structp png_ptr),
1055    PNG_EMPTY);
1056 #  endif
1057 #endif
1058 
1059 /* Reset the CRC variable */
1060 PNG_INTERNAL_FUNCTION(void,png_reset_crc,(png_structrp png_ptr),PNG_EMPTY);
1061 
1062 /* Write the "data" buffer to whatever output you are using */
1063 PNG_INTERNAL_FUNCTION(void,png_write_data,(png_structrp png_ptr,
1064     png_const_bytep data, size_t length),PNG_EMPTY);
1065 
1066 /* Read and check the PNG file signature */
1067 PNG_INTERNAL_FUNCTION(void,png_read_sig,(png_structrp png_ptr,
1068    png_inforp info_ptr),PNG_EMPTY);
1069 
1070 /* Read the chunk header (length + type name) */
1071 PNG_INTERNAL_FUNCTION(png_uint_32,png_read_chunk_header,(png_structrp png_ptr),
1072    PNG_EMPTY);
1073 
1074 /* Read data from whatever input you are using into the "data" buffer */
1075 PNG_INTERNAL_FUNCTION(void,png_read_data,(png_structrp png_ptr, png_bytep data,
1076     size_t length),PNG_EMPTY);
1077 
1078 /* Read bytes into buf, and update png_ptr->crc */
1079 PNG_INTERNAL_FUNCTION(void,png_crc_read,(png_structrp png_ptr, png_bytep buf,
1080     png_uint_32 length),PNG_EMPTY);
1081 
1082 /* Read "skip" bytes, read the file crc, and (optionally) verify png_ptr->crc */
1083 PNG_INTERNAL_FUNCTION(int,png_crc_finish,(png_structrp png_ptr,
1084    png_uint_32 skip),PNG_EMPTY);
1085 
1086 /* Read the CRC from the file and compare it to the libpng calculated CRC */
1087 PNG_INTERNAL_FUNCTION(int,png_crc_error,(png_structrp png_ptr),PNG_EMPTY);
1088 
1089 /* Calculate the CRC over a section of data.  Note that we are only
1090  * passing a maximum of 64K on systems that have this as a memory limit,
1091  * since this is the maximum buffer size we can specify.
1092  */
1093 PNG_INTERNAL_FUNCTION(void,png_calculate_crc,(png_structrp png_ptr,
1094    png_const_bytep ptr, size_t length),PNG_EMPTY);
1095 
1096 #ifdef PNG_WRITE_FLUSH_SUPPORTED
1097 PNG_INTERNAL_FUNCTION(void,png_flush,(png_structrp png_ptr),PNG_EMPTY);
1098 #endif
1099 
1100 /* Write various chunks */
1101 
1102 /* Write the IHDR chunk, and update the png_struct with the necessary
1103  * information.
1104  */
1105 PNG_INTERNAL_FUNCTION(void,png_write_IHDR,(png_structrp png_ptr,
1106    png_uint_32 width, png_uint_32 height, int bit_depth, int color_type,
1107    int compression_method, int filter_method, int interlace_method),PNG_EMPTY);
1108 
1109 PNG_INTERNAL_FUNCTION(void,png_write_PLTE,(png_structrp png_ptr,
1110    png_const_colorp palette, png_uint_32 num_pal),PNG_EMPTY);
1111 
1112 PNG_INTERNAL_FUNCTION(void,png_compress_IDAT,(png_structrp png_ptr,
1113    png_const_bytep row_data, png_alloc_size_t row_data_length, int flush),
1114    PNG_EMPTY);
1115 
1116 PNG_INTERNAL_FUNCTION(void,png_write_IEND,(png_structrp png_ptr),PNG_EMPTY);
1117 
1118 #ifdef PNG_WRITE_gAMA_SUPPORTED
1119 PNG_INTERNAL_FUNCTION(void,png_write_gAMA_fixed,(png_structrp png_ptr,
1120     png_fixed_point file_gamma),PNG_EMPTY);
1121 #endif
1122 
1123 #ifdef PNG_WRITE_sBIT_SUPPORTED
1124 PNG_INTERNAL_FUNCTION(void,png_write_sBIT,(png_structrp png_ptr,
1125     png_const_color_8p sbit, int color_type),PNG_EMPTY);
1126 #endif
1127 
1128 #ifdef PNG_WRITE_cHRM_SUPPORTED
1129 PNG_INTERNAL_FUNCTION(void,png_write_cHRM_fixed,(png_structrp png_ptr,
1130     const png_xy *xy), PNG_EMPTY);
1131    /* The xy value must have been previously validated */
1132 #endif
1133 
1134 #ifdef PNG_WRITE_sRGB_SUPPORTED
1135 PNG_INTERNAL_FUNCTION(void,png_write_sRGB,(png_structrp png_ptr,
1136     int intent),PNG_EMPTY);
1137 #endif
1138 
1139 #ifdef PNG_WRITE_eXIf_SUPPORTED
1140 PNG_INTERNAL_FUNCTION(void,png_write_eXIf,(png_structrp png_ptr,
1141     png_bytep exif, int num_exif),PNG_EMPTY);
1142 #endif
1143 
1144 #ifdef PNG_WRITE_iCCP_SUPPORTED
1145 PNG_INTERNAL_FUNCTION(void,png_write_iCCP,(png_structrp png_ptr,
1146    png_const_charp name, png_const_bytep profile), PNG_EMPTY);
1147    /* The profile must have been previously validated for correctness, the
1148     * length comes from the first four bytes.  Only the base, deflate,
1149     * compression is supported.
1150     */
1151 #endif
1152 
1153 #ifdef PNG_WRITE_sPLT_SUPPORTED
1154 PNG_INTERNAL_FUNCTION(void,png_write_sPLT,(png_structrp png_ptr,
1155     png_const_sPLT_tp palette),PNG_EMPTY);
1156 #endif
1157 
1158 #ifdef PNG_WRITE_tRNS_SUPPORTED
1159 PNG_INTERNAL_FUNCTION(void,png_write_tRNS,(png_structrp png_ptr,
1160     png_const_bytep trans, png_const_color_16p values, int number,
1161     int color_type),PNG_EMPTY);
1162 #endif
1163 
1164 #ifdef PNG_WRITE_bKGD_SUPPORTED
1165 PNG_INTERNAL_FUNCTION(void,png_write_bKGD,(png_structrp png_ptr,
1166     png_const_color_16p values, int color_type),PNG_EMPTY);
1167 #endif
1168 
1169 #ifdef PNG_WRITE_hIST_SUPPORTED
1170 PNG_INTERNAL_FUNCTION(void,png_write_hIST,(png_structrp png_ptr,
1171     png_const_uint_16p hist, int num_hist),PNG_EMPTY);
1172 #endif
1173 
1174 /* Chunks that have keywords */
1175 #ifdef PNG_WRITE_tEXt_SUPPORTED
1176 PNG_INTERNAL_FUNCTION(void,png_write_tEXt,(png_structrp png_ptr,
1177    png_const_charp key, png_const_charp text, size_t text_len),PNG_EMPTY);
1178 #endif
1179 
1180 #ifdef PNG_WRITE_zTXt_SUPPORTED
1181 PNG_INTERNAL_FUNCTION(void,png_write_zTXt,(png_structrp png_ptr, png_const_charp
1182     key, png_const_charp text, int compression),PNG_EMPTY);
1183 #endif
1184 
1185 #ifdef PNG_WRITE_iTXt_SUPPORTED
1186 PNG_INTERNAL_FUNCTION(void,png_write_iTXt,(png_structrp png_ptr,
1187     int compression, png_const_charp key, png_const_charp lang,
1188     png_const_charp lang_key, png_const_charp text),PNG_EMPTY);
1189 #endif
1190 
1191 #ifdef PNG_TEXT_SUPPORTED  /* Added at version 1.0.14 and 1.2.4 */
1192 PNG_INTERNAL_FUNCTION(int,png_set_text_2,(png_const_structrp png_ptr,
1193     png_inforp info_ptr, png_const_textp text_ptr, int num_text),PNG_EMPTY);
1194 #endif
1195 
1196 #ifdef PNG_WRITE_oFFs_SUPPORTED
1197 PNG_INTERNAL_FUNCTION(void,png_write_oFFs,(png_structrp png_ptr,
1198     png_int_32 x_offset, png_int_32 y_offset, int unit_type),PNG_EMPTY);
1199 #endif
1200 
1201 #ifdef PNG_WRITE_pCAL_SUPPORTED
1202 PNG_INTERNAL_FUNCTION(void,png_write_pCAL,(png_structrp png_ptr,
1203     png_charp purpose, png_int_32 X0, png_int_32 X1, int type, int nparams,
1204     png_const_charp units, png_charpp params),PNG_EMPTY);
1205 #endif
1206 
1207 #ifdef PNG_WRITE_pHYs_SUPPORTED
1208 PNG_INTERNAL_FUNCTION(void,png_write_pHYs,(png_structrp png_ptr,
1209     png_uint_32 x_pixels_per_unit, png_uint_32 y_pixels_per_unit,
1210     int unit_type),PNG_EMPTY);
1211 #endif
1212 
1213 #ifdef PNG_WRITE_tIME_SUPPORTED
1214 PNG_INTERNAL_FUNCTION(void,png_write_tIME,(png_structrp png_ptr,
1215     png_const_timep mod_time),PNG_EMPTY);
1216 #endif
1217 
1218 #ifdef PNG_WRITE_sCAL_SUPPORTED
1219 PNG_INTERNAL_FUNCTION(void,png_write_sCAL_s,(png_structrp png_ptr,
1220     int unit, png_const_charp width, png_const_charp height),PNG_EMPTY);
1221 #endif
1222 
1223 /* Called when finished processing a row of data */
1224 PNG_INTERNAL_FUNCTION(void,png_write_finish_row,(png_structrp png_ptr),
1225     PNG_EMPTY);
1226 
1227 /* Internal use only.   Called before first row of data */
1228 PNG_INTERNAL_FUNCTION(void,png_write_start_row,(png_structrp png_ptr),
1229     PNG_EMPTY);
1230 
1231 /* Combine a row of data, dealing with alpha, etc. if requested.  'row' is an
1232  * array of png_ptr->width pixels.  If the image is not interlaced or this
1233  * is the final pass this just does a memcpy, otherwise the "display" flag
1234  * is used to determine whether to copy pixels that are not in the current pass.
1235  *
1236  * Because 'png_do_read_interlace' (below) replicates pixels this allows this
1237  * function to achieve the documented 'blocky' appearance during interlaced read
1238  * if display is 1 and the 'sparkle' appearance, where existing pixels in 'row'
1239  * are not changed if they are not in the current pass, when display is 0.
1240  *
1241  * 'display' must be 0 or 1, otherwise the memcpy will be done regardless.
1242  *
1243  * The API always reads from the png_struct row buffer and always assumes that
1244  * it is full width (png_do_read_interlace has already been called.)
1245  *
1246  * This function is only ever used to write to row buffers provided by the
1247  * caller of the relevant libpng API and the row must have already been
1248  * transformed by the read transformations.
1249  *
1250  * The PNG_USE_COMPILE_TIME_MASKS option causes generation of pre-computed
1251  * bitmasks for use within the code, otherwise runtime generated masks are used.
1252  * The default is compile time masks.
1253  */
1254 #ifndef PNG_USE_COMPILE_TIME_MASKS
1255 #  define PNG_USE_COMPILE_TIME_MASKS 1
1256 #endif
1257 PNG_INTERNAL_FUNCTION(void,png_combine_row,(png_const_structrp png_ptr,
1258     png_bytep row, int display),PNG_EMPTY);
1259 
1260 #ifdef PNG_READ_INTERLACING_SUPPORTED
1261 /* Expand an interlaced row: the 'row_info' describes the pass data that has
1262  * been read in and must correspond to the pixels in 'row', the pixels are
1263  * expanded (moved apart) in 'row' to match the final layout, when doing this
1264  * the pixels are *replicated* to the intervening space.  This is essential for
1265  * the correct operation of png_combine_row, above.
1266  */
1267 PNG_INTERNAL_FUNCTION(void,png_do_read_interlace,(png_row_infop row_info,
1268     png_bytep row, int pass, png_uint_32 transformations),PNG_EMPTY);
1269 #endif
1270 
1271 /* GRR TO DO (2.0 or whenever):  simplify other internal calling interfaces */
1272 
1273 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1274 /* Grab pixels out of a row for an interlaced pass */
1275 PNG_INTERNAL_FUNCTION(void,png_do_write_interlace,(png_row_infop row_info,
1276     png_bytep row, int pass),PNG_EMPTY);
1277 #endif
1278 
1279 /* Unfilter a row: check the filter value before calling this, there is no point
1280  * calling it for PNG_FILTER_VALUE_NONE.
1281  */
1282 PNG_INTERNAL_FUNCTION(void,png_read_filter_row,(png_structrp pp, png_row_infop
1283     row_info, png_bytep row, png_const_bytep prev_row, int filter),PNG_EMPTY);
1284 
1285 #if PNG_ARM_NEON_OPT > 0
1286 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_up_neon,(png_row_infop row_info,
1287     png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1288 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_neon,(png_row_infop
1289     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1290 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_neon,(png_row_infop
1291     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1292 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_neon,(png_row_infop
1293     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1294 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_neon,(png_row_infop
1295     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1296 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_neon,(png_row_infop
1297     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1298 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_neon,(png_row_infop
1299     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1300 #endif
1301 
1302 #if PNG_MIPS_MSA_IMPLEMENTATION == 1
1303 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_up_msa,(png_row_infop row_info,
1304     png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1305 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_msa,(png_row_infop
1306     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1307 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_msa,(png_row_infop
1308     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1309 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_msa,(png_row_infop
1310     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1311 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_msa,(png_row_infop
1312     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1313 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_msa,(png_row_infop
1314     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1315 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_msa,(png_row_infop
1316     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1317 #endif
1318 
1319 #if PNG_MIPS_MMI_IMPLEMENTATION > 0
1320 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_up_mmi,(png_row_infop row_info,
1321     png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1322 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_mmi,(png_row_infop
1323     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1324 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_mmi,(png_row_infop
1325     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1326 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_mmi,(png_row_infop
1327     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1328 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_mmi,(png_row_infop
1329     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1330 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_mmi,(png_row_infop
1331     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1332 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_mmi,(png_row_infop
1333     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1334 #endif
1335 
1336 #if PNG_POWERPC_VSX_OPT > 0
1337 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_up_vsx,(png_row_infop row_info,
1338     png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1339 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_vsx,(png_row_infop
1340     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1341 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_vsx,(png_row_infop
1342     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1343 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_vsx,(png_row_infop
1344     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1345 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_vsx,(png_row_infop
1346     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1347 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_vsx,(png_row_infop
1348     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1349 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_vsx,(png_row_infop
1350     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1351 #endif
1352 
1353 #if PNG_INTEL_SSE_IMPLEMENTATION > 0
1354 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_sse2,(png_row_infop
1355     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1356 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_sse2,(png_row_infop
1357     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1358 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_sse2,(png_row_infop
1359     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1360 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_sse2,(png_row_infop
1361     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1362 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_sse2,(png_row_infop
1363     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1364 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_sse2,(png_row_infop
1365     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1366 #endif
1367 
1368 #if PNG_LOONGARCH_LSX_IMPLEMENTATION == 1
1369 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_up_lsx,(png_row_infop
1370     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1371 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_lsx,(png_row_infop
1372     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1373 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_lsx,(png_row_infop
1374     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1375 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_lsx,(png_row_infop
1376     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1377 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_lsx,(png_row_infop
1378     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1379 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_lsx,(png_row_infop
1380     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1381 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_lsx,(png_row_infop
1382     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1383 #endif
1384 
1385 /* Choose the best filter to use and filter the row data */
1386 PNG_INTERNAL_FUNCTION(void,png_write_find_filter,(png_structrp png_ptr,
1387     png_row_infop row_info),PNG_EMPTY);
1388 
1389 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1390 PNG_INTERNAL_FUNCTION(void,png_read_IDAT_data,(png_structrp png_ptr,
1391    png_bytep output, png_alloc_size_t avail_out),PNG_EMPTY);
1392    /* Read 'avail_out' bytes of data from the IDAT stream.  If the output buffer
1393     * is NULL the function checks, instead, for the end of the stream.  In this
1394     * case a benign error will be issued if the stream end is not found or if
1395     * extra data has to be consumed.
1396     */
1397 PNG_INTERNAL_FUNCTION(void,png_read_finish_IDAT,(png_structrp png_ptr),
1398    PNG_EMPTY);
1399    /* This cleans up when the IDAT LZ stream does not end when the last image
1400     * byte is read; there is still some pending input.
1401     */
1402 
1403 PNG_INTERNAL_FUNCTION(void,png_read_finish_row,(png_structrp png_ptr),
1404    PNG_EMPTY);
1405    /* Finish a row while reading, dealing with interlacing passes, etc. */
1406 #endif /* SEQUENTIAL_READ */
1407 
1408 /* Initialize the row buffers, etc. */
1409 PNG_INTERNAL_FUNCTION(void,png_read_start_row,(png_structrp png_ptr),PNG_EMPTY);
1410 
1411 #if ZLIB_VERNUM >= 0x1240
1412 PNG_INTERNAL_FUNCTION(int,png_zlib_inflate,(png_structrp png_ptr, int flush),
1413       PNG_EMPTY);
1414 #  define PNG_INFLATE(pp, flush) png_zlib_inflate(pp, flush)
1415 #else /* Zlib < 1.2.4 */
1416 #  define PNG_INFLATE(pp, flush) inflate(&(pp)->zstream, flush)
1417 #endif /* Zlib < 1.2.4 */
1418 
1419 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1420 /* Optional call to update the users info structure */
1421 PNG_INTERNAL_FUNCTION(void,png_read_transform_info,(png_structrp png_ptr,
1422     png_inforp info_ptr),PNG_EMPTY);
1423 #endif
1424 
1425 /* Shared transform functions, defined in pngtran.c */
1426 #if defined(PNG_WRITE_FILLER_SUPPORTED) || \
1427     defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
1428 PNG_INTERNAL_FUNCTION(void,png_do_strip_channel,(png_row_infop row_info,
1429     png_bytep row, int at_start),PNG_EMPTY);
1430 #endif
1431 
1432 #ifdef PNG_16BIT_SUPPORTED
1433 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
1434 PNG_INTERNAL_FUNCTION(void,png_do_swap,(png_row_infop row_info,
1435     png_bytep row),PNG_EMPTY);
1436 #endif
1437 #endif
1438 
1439 #if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
1440     defined(PNG_WRITE_PACKSWAP_SUPPORTED)
1441 PNG_INTERNAL_FUNCTION(void,png_do_packswap,(png_row_infop row_info,
1442     png_bytep row),PNG_EMPTY);
1443 #endif
1444 
1445 #if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
1446 PNG_INTERNAL_FUNCTION(void,png_do_invert,(png_row_infop row_info,
1447     png_bytep row),PNG_EMPTY);
1448 #endif
1449 
1450 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
1451 PNG_INTERNAL_FUNCTION(void,png_do_bgr,(png_row_infop row_info,
1452     png_bytep row),PNG_EMPTY);
1453 #endif
1454 
1455 /* The following decodes the appropriate chunks, and does error correction,
1456  * then calls the appropriate callback for the chunk if it is valid.
1457  */
1458 
1459 /* Decode the IHDR chunk */
1460 PNG_INTERNAL_FUNCTION(void,png_handle_IHDR,(png_structrp png_ptr,
1461     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1462 PNG_INTERNAL_FUNCTION(void,png_handle_PLTE,(png_structrp png_ptr,
1463     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1464 PNG_INTERNAL_FUNCTION(void,png_handle_IEND,(png_structrp png_ptr,
1465     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1466 
1467 #ifdef PNG_READ_bKGD_SUPPORTED
1468 PNG_INTERNAL_FUNCTION(void,png_handle_bKGD,(png_structrp png_ptr,
1469     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1470 #endif
1471 
1472 #ifdef PNG_READ_cHRM_SUPPORTED
1473 PNG_INTERNAL_FUNCTION(void,png_handle_cHRM,(png_structrp png_ptr,
1474     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1475 #endif
1476 
1477 #ifdef PNG_READ_eXIf_SUPPORTED
1478 PNG_INTERNAL_FUNCTION(void,png_handle_eXIf,(png_structrp png_ptr,
1479     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1480 #endif
1481 
1482 #ifdef PNG_READ_gAMA_SUPPORTED
1483 PNG_INTERNAL_FUNCTION(void,png_handle_gAMA,(png_structrp png_ptr,
1484     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1485 #endif
1486 
1487 #ifdef PNG_READ_hIST_SUPPORTED
1488 PNG_INTERNAL_FUNCTION(void,png_handle_hIST,(png_structrp png_ptr,
1489     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1490 #endif
1491 
1492 #ifdef PNG_READ_iCCP_SUPPORTED
1493 PNG_INTERNAL_FUNCTION(void,png_handle_iCCP,(png_structrp png_ptr,
1494     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1495 #endif /* READ_iCCP */
1496 
1497 #ifdef PNG_READ_iTXt_SUPPORTED
1498 PNG_INTERNAL_FUNCTION(void,png_handle_iTXt,(png_structrp png_ptr,
1499     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1500 #endif
1501 
1502 #ifdef PNG_READ_oFFs_SUPPORTED
1503 PNG_INTERNAL_FUNCTION(void,png_handle_oFFs,(png_structrp png_ptr,
1504     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1505 #endif
1506 
1507 #ifdef PNG_READ_pCAL_SUPPORTED
1508 PNG_INTERNAL_FUNCTION(void,png_handle_pCAL,(png_structrp png_ptr,
1509     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1510 #endif
1511 
1512 #ifdef PNG_READ_pHYs_SUPPORTED
1513 PNG_INTERNAL_FUNCTION(void,png_handle_pHYs,(png_structrp png_ptr,
1514     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1515 #endif
1516 
1517 #ifdef PNG_READ_sBIT_SUPPORTED
1518 PNG_INTERNAL_FUNCTION(void,png_handle_sBIT,(png_structrp png_ptr,
1519     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1520 #endif
1521 
1522 #ifdef PNG_READ_sCAL_SUPPORTED
1523 PNG_INTERNAL_FUNCTION(void,png_handle_sCAL,(png_structrp png_ptr,
1524     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1525 #endif
1526 
1527 #ifdef PNG_READ_sPLT_SUPPORTED
1528 PNG_INTERNAL_FUNCTION(void,png_handle_sPLT,(png_structrp png_ptr,
1529     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1530 #endif /* READ_sPLT */
1531 
1532 #ifdef PNG_READ_sRGB_SUPPORTED
1533 PNG_INTERNAL_FUNCTION(void,png_handle_sRGB,(png_structrp png_ptr,
1534     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1535 #endif
1536 
1537 #ifdef PNG_READ_tEXt_SUPPORTED
1538 PNG_INTERNAL_FUNCTION(void,png_handle_tEXt,(png_structrp png_ptr,
1539     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1540 #endif
1541 
1542 #ifdef PNG_READ_tIME_SUPPORTED
1543 PNG_INTERNAL_FUNCTION(void,png_handle_tIME,(png_structrp png_ptr,
1544     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1545 #endif
1546 
1547 #ifdef PNG_READ_tRNS_SUPPORTED
1548 PNG_INTERNAL_FUNCTION(void,png_handle_tRNS,(png_structrp png_ptr,
1549     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1550 #endif
1551 
1552 #ifdef PNG_READ_zTXt_SUPPORTED
1553 PNG_INTERNAL_FUNCTION(void,png_handle_zTXt,(png_structrp png_ptr,
1554     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1555 #endif
1556 
1557 PNG_INTERNAL_FUNCTION(void,png_check_chunk_name,(png_const_structrp png_ptr,
1558     png_uint_32 chunk_name),PNG_EMPTY);
1559 
1560 PNG_INTERNAL_FUNCTION(void,png_check_chunk_length,(png_const_structrp png_ptr,
1561     png_uint_32 chunk_length),PNG_EMPTY);
1562 
1563 PNG_INTERNAL_FUNCTION(void,png_handle_unknown,(png_structrp png_ptr,
1564     png_inforp info_ptr, png_uint_32 length, int keep),PNG_EMPTY);
1565    /* This is the function that gets called for unknown chunks.  The 'keep'
1566     * argument is either non-zero for a known chunk that has been set to be
1567     * handled as unknown or zero for an unknown chunk.  By default the function
1568     * just skips the chunk or errors out if it is critical.
1569     */
1570 
1571 #if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) ||\
1572     defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
1573 PNG_INTERNAL_FUNCTION(int,png_chunk_unknown_handling,
1574     (png_const_structrp png_ptr, png_uint_32 chunk_name),PNG_EMPTY);
1575    /* Exactly as the API png_handle_as_unknown() except that the argument is a
1576     * 32-bit chunk name, not a string.
1577     */
1578 #endif /* READ_UNKNOWN_CHUNKS || HANDLE_AS_UNKNOWN */
1579 
1580 /* Handle the transformations for reading and writing */
1581 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1582 PNG_INTERNAL_FUNCTION(void,png_do_read_transformations,(png_structrp png_ptr,
1583    png_row_infop row_info),PNG_EMPTY);
1584 #endif
1585 #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
1586 PNG_INTERNAL_FUNCTION(void,png_do_write_transformations,(png_structrp png_ptr,
1587    png_row_infop row_info),PNG_EMPTY);
1588 #endif
1589 
1590 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1591 PNG_INTERNAL_FUNCTION(void,png_init_read_transformations,(png_structrp png_ptr),
1592     PNG_EMPTY);
1593 #endif
1594 
1595 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1596 PNG_INTERNAL_FUNCTION(void,png_push_read_chunk,(png_structrp png_ptr,
1597     png_inforp info_ptr),PNG_EMPTY);
1598 PNG_INTERNAL_FUNCTION(void,png_push_read_sig,(png_structrp png_ptr,
1599     png_inforp info_ptr),PNG_EMPTY);
1600 PNG_INTERNAL_FUNCTION(void,png_push_check_crc,(png_structrp png_ptr),PNG_EMPTY);
1601 PNG_INTERNAL_FUNCTION(void,png_push_save_buffer,(png_structrp png_ptr),
1602     PNG_EMPTY);
1603 PNG_INTERNAL_FUNCTION(void,png_push_restore_buffer,(png_structrp png_ptr,
1604     png_bytep buffer, size_t buffer_length),PNG_EMPTY);
1605 PNG_INTERNAL_FUNCTION(void,png_push_read_IDAT,(png_structrp png_ptr),PNG_EMPTY);
1606 PNG_INTERNAL_FUNCTION(void,png_process_IDAT_data,(png_structrp png_ptr,
1607     png_bytep buffer, size_t buffer_length),PNG_EMPTY);
1608 PNG_INTERNAL_FUNCTION(void,png_push_process_row,(png_structrp png_ptr),
1609     PNG_EMPTY);
1610 PNG_INTERNAL_FUNCTION(void,png_push_handle_unknown,(png_structrp png_ptr,
1611    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1612 PNG_INTERNAL_FUNCTION(void,png_push_have_info,(png_structrp png_ptr,
1613    png_inforp info_ptr),PNG_EMPTY);
1614 PNG_INTERNAL_FUNCTION(void,png_push_have_end,(png_structrp png_ptr,
1615    png_inforp info_ptr),PNG_EMPTY);
1616 PNG_INTERNAL_FUNCTION(void,png_push_have_row,(png_structrp png_ptr,
1617     png_bytep row),PNG_EMPTY);
1618 PNG_INTERNAL_FUNCTION(void,png_push_read_end,(png_structrp png_ptr,
1619     png_inforp info_ptr),PNG_EMPTY);
1620 PNG_INTERNAL_FUNCTION(void,png_process_some_data,(png_structrp png_ptr,
1621     png_inforp info_ptr),PNG_EMPTY);
1622 PNG_INTERNAL_FUNCTION(void,png_read_push_finish_row,(png_structrp png_ptr),
1623     PNG_EMPTY);
1624 #  ifdef PNG_READ_tEXt_SUPPORTED
1625 PNG_INTERNAL_FUNCTION(void,png_push_handle_tEXt,(png_structrp png_ptr,
1626     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1627 PNG_INTERNAL_FUNCTION(void,png_push_read_tEXt,(png_structrp png_ptr,
1628     png_inforp info_ptr),PNG_EMPTY);
1629 #  endif
1630 #  ifdef PNG_READ_zTXt_SUPPORTED
1631 PNG_INTERNAL_FUNCTION(void,png_push_handle_zTXt,(png_structrp png_ptr,
1632     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1633 PNG_INTERNAL_FUNCTION(void,png_push_read_zTXt,(png_structrp png_ptr,
1634     png_inforp info_ptr),PNG_EMPTY);
1635 #  endif
1636 #  ifdef PNG_READ_iTXt_SUPPORTED
1637 PNG_INTERNAL_FUNCTION(void,png_push_handle_iTXt,(png_structrp png_ptr,
1638     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1639 PNG_INTERNAL_FUNCTION(void,png_push_read_iTXt,(png_structrp png_ptr,
1640     png_inforp info_ptr),PNG_EMPTY);
1641 #  endif
1642 
1643 #endif /* PROGRESSIVE_READ */
1644 
1645 /* Added at libpng version 1.6.0 */
1646 #ifdef PNG_GAMMA_SUPPORTED
1647 PNG_INTERNAL_FUNCTION(void,png_colorspace_set_gamma,(png_const_structrp png_ptr,
1648     png_colorspacerp colorspace, png_fixed_point gAMA), PNG_EMPTY);
1649    /* Set the colorspace gamma with a value provided by the application or by
1650     * the gAMA chunk on read.  The value will override anything set by an ICC
1651     * profile.
1652     */
1653 
1654 PNG_INTERNAL_FUNCTION(void,png_colorspace_sync_info,(png_const_structrp png_ptr,
1655     png_inforp info_ptr), PNG_EMPTY);
1656    /* Synchronize the info 'valid' flags with the colorspace */
1657 
1658 PNG_INTERNAL_FUNCTION(void,png_colorspace_sync,(png_const_structrp png_ptr,
1659     png_inforp info_ptr), PNG_EMPTY);
1660    /* Copy the png_struct colorspace to the info_struct and call the above to
1661     * synchronize the flags.  Checks for NULL info_ptr and does nothing.
1662     */
1663 #endif
1664 
1665 /* Added at libpng version 1.4.0 */
1666 #ifdef PNG_COLORSPACE_SUPPORTED
1667 /* These internal functions are for maintaining the colorspace structure within
1668  * a png_info or png_struct (or, indeed, both).
1669  */
1670 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_chromaticities,
1671    (png_const_structrp png_ptr, png_colorspacerp colorspace, const png_xy *xy,
1672     int preferred), PNG_EMPTY);
1673 
1674 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_endpoints,
1675    (png_const_structrp png_ptr, png_colorspacerp colorspace, const png_XYZ *XYZ,
1676     int preferred), PNG_EMPTY);
1677 
1678 #ifdef PNG_sRGB_SUPPORTED
1679 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_sRGB,(png_const_structrp png_ptr,
1680    png_colorspacerp colorspace, int intent), PNG_EMPTY);
1681    /* This does set the colorspace gAMA and cHRM values too, but doesn't set the
1682     * flags to write them, if it returns false there was a problem and an error
1683     * message has already been output (but the colorspace may still need to be
1684     * synced to record the invalid flag).
1685     */
1686 #endif /* sRGB */
1687 
1688 #ifdef PNG_iCCP_SUPPORTED
1689 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_ICC,(png_const_structrp png_ptr,
1690    png_colorspacerp colorspace, png_const_charp name,
1691    png_uint_32 profile_length, png_const_bytep profile, int color_type),
1692    PNG_EMPTY);
1693    /* The 'name' is used for information only */
1694 
1695 /* Routines for checking parts of an ICC profile. */
1696 #ifdef PNG_READ_iCCP_SUPPORTED
1697 PNG_INTERNAL_FUNCTION(int,png_icc_check_length,(png_const_structrp png_ptr,
1698    png_colorspacerp colorspace, png_const_charp name,
1699    png_uint_32 profile_length), PNG_EMPTY);
1700 #endif /* READ_iCCP */
1701 PNG_INTERNAL_FUNCTION(int,png_icc_check_header,(png_const_structrp png_ptr,
1702    png_colorspacerp colorspace, png_const_charp name,
1703    png_uint_32 profile_length,
1704    png_const_bytep profile /* first 132 bytes only */, int color_type),
1705    PNG_EMPTY);
1706 PNG_INTERNAL_FUNCTION(int,png_icc_check_tag_table,(png_const_structrp png_ptr,
1707    png_colorspacerp colorspace, png_const_charp name,
1708    png_uint_32 profile_length,
1709    png_const_bytep profile /* header plus whole tag table */), PNG_EMPTY);
1710 #ifdef PNG_sRGB_SUPPORTED
1711 PNG_INTERNAL_FUNCTION(void,png_icc_set_sRGB,(
1712    png_const_structrp png_ptr, png_colorspacerp colorspace,
1713    png_const_bytep profile, uLong adler), PNG_EMPTY);
1714    /* 'adler' is the Adler32 checksum of the uncompressed profile data. It may
1715     * be zero to indicate that it is not available.  It is used, if provided,
1716     * as a fast check on the profile when checking to see if it is sRGB.
1717     */
1718 #endif
1719 #endif /* iCCP */
1720 
1721 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1722 PNG_INTERNAL_FUNCTION(void,png_colorspace_set_rgb_coefficients,
1723    (png_structrp png_ptr), PNG_EMPTY);
1724    /* Set the rgb_to_gray coefficients from the colorspace Y values */
1725 #endif /* READ_RGB_TO_GRAY */
1726 #endif /* COLORSPACE */
1727 
1728 /* Added at libpng version 1.4.0 */
1729 PNG_INTERNAL_FUNCTION(void,png_check_IHDR,(png_const_structrp png_ptr,
1730     png_uint_32 width, png_uint_32 height, int bit_depth,
1731     int color_type, int interlace_type, int compression_type,
1732     int filter_type),PNG_EMPTY);
1733 
1734 /* Added at libpng version 1.5.10 */
1735 #if defined(PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED) || \
1736     defined(PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED)
1737 PNG_INTERNAL_FUNCTION(void,png_do_check_palette_indexes,
1738    (png_structrp png_ptr, png_row_infop row_info),PNG_EMPTY);
1739 #endif
1740 
1741 #if defined(PNG_FLOATING_POINT_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED)
1742 PNG_INTERNAL_FUNCTION(void,png_fixed_error,(png_const_structrp png_ptr,
1743    png_const_charp name),PNG_NORETURN);
1744 #endif
1745 
1746 /* Puts 'string' into 'buffer' at buffer[pos], taking care never to overwrite
1747  * the end.  Always leaves the buffer nul terminated.  Never errors out (and
1748  * there is no error code.)
1749  */
1750 PNG_INTERNAL_FUNCTION(size_t,png_safecat,(png_charp buffer, size_t bufsize,
1751    size_t pos, png_const_charp string),PNG_EMPTY);
1752 
1753 /* Various internal functions to handle formatted warning messages, currently
1754  * only implemented for warnings.
1755  */
1756 #if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_TIME_RFC1123_SUPPORTED)
1757 /* Utility to dump an unsigned value into a buffer, given a start pointer and
1758  * and end pointer (which should point just *beyond* the end of the buffer!)
1759  * Returns the pointer to the start of the formatted string.  This utility only
1760  * does unsigned values.
1761  */
1762 PNG_INTERNAL_FUNCTION(png_charp,png_format_number,(png_const_charp start,
1763    png_charp end, int format, png_alloc_size_t number),PNG_EMPTY);
1764 
1765 /* Convenience macro that takes an array: */
1766 #define PNG_FORMAT_NUMBER(buffer,format,number) \
1767    png_format_number(buffer, buffer + (sizeof buffer), format, number)
1768 
1769 /* Suggested size for a number buffer (enough for 64 bits and a sign!) */
1770 #define PNG_NUMBER_BUFFER_SIZE 24
1771 
1772 /* These are the integer formats currently supported, the name is formed from
1773  * the standard printf(3) format string.
1774  */
1775 #define PNG_NUMBER_FORMAT_u     1 /* chose unsigned API! */
1776 #define PNG_NUMBER_FORMAT_02u   2
1777 #define PNG_NUMBER_FORMAT_d     1 /* chose signed API! */
1778 #define PNG_NUMBER_FORMAT_02d   2
1779 #define PNG_NUMBER_FORMAT_x     3
1780 #define PNG_NUMBER_FORMAT_02x   4
1781 #define PNG_NUMBER_FORMAT_fixed 5 /* choose the signed API */
1782 #endif
1783 
1784 #ifdef PNG_WARNINGS_SUPPORTED
1785 /* New defines and members adding in libpng-1.5.4 */
1786 #  define PNG_WARNING_PARAMETER_SIZE 32
1787 #  define PNG_WARNING_PARAMETER_COUNT 8 /* Maximum 9; see pngerror.c */
1788 
1789 /* An l-value of this type has to be passed to the APIs below to cache the
1790  * values of the parameters to a formatted warning message.
1791  */
1792 typedef char png_warning_parameters[PNG_WARNING_PARAMETER_COUNT][
1793    PNG_WARNING_PARAMETER_SIZE];
1794 
1795 PNG_INTERNAL_FUNCTION(void,png_warning_parameter,(png_warning_parameters p,
1796    int number, png_const_charp string),PNG_EMPTY);
1797    /* Parameters are limited in size to PNG_WARNING_PARAMETER_SIZE characters,
1798     * including the trailing '\0'.
1799     */
1800 PNG_INTERNAL_FUNCTION(void,png_warning_parameter_unsigned,
1801    (png_warning_parameters p, int number, int format, png_alloc_size_t value),
1802    PNG_EMPTY);
1803    /* Use png_alloc_size_t because it is an unsigned type as big as any we
1804     * need to output.  Use the following for a signed value.
1805     */
1806 PNG_INTERNAL_FUNCTION(void,png_warning_parameter_signed,
1807    (png_warning_parameters p, int number, int format, png_int_32 value),
1808    PNG_EMPTY);
1809 
1810 PNG_INTERNAL_FUNCTION(void,png_formatted_warning,(png_const_structrp png_ptr,
1811    png_warning_parameters p, png_const_charp message),PNG_EMPTY);
1812    /* 'message' follows the X/Open approach of using @1, @2 to insert
1813     * parameters previously supplied using the above functions.  Errors in
1814     * specifying the parameters will simply result in garbage substitutions.
1815     */
1816 #endif
1817 
1818 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
1819 /* Application errors (new in 1.6); use these functions (declared below) for
1820  * errors in the parameters or order of API function calls on read.  The
1821  * 'warning' should be used for an error that can be handled completely; the
1822  * 'error' for one which can be handled safely but which may lose application
1823  * information or settings.
1824  *
1825  * By default these both result in a png_error call prior to release, while in a
1826  * released version the 'warning' is just a warning.  However if the application
1827  * explicitly disables benign errors (explicitly permitting the code to lose
1828  * information) they both turn into warnings.
1829  *
1830  * If benign errors aren't supported they end up as the corresponding base call
1831  * (png_warning or png_error.)
1832  */
1833 PNG_INTERNAL_FUNCTION(void,png_app_warning,(png_const_structrp png_ptr,
1834    png_const_charp message),PNG_EMPTY);
1835    /* The application provided invalid parameters to an API function or called
1836     * an API function at the wrong time, libpng can completely recover.
1837     */
1838 
1839 PNG_INTERNAL_FUNCTION(void,png_app_error,(png_const_structrp png_ptr,
1840    png_const_charp message),PNG_EMPTY);
1841    /* As above but libpng will ignore the call, or attempt some other partial
1842     * recovery from the error.
1843     */
1844 #else
1845 #  define png_app_warning(pp,s) png_warning(pp,s)
1846 #  define png_app_error(pp,s) png_error(pp,s)
1847 #endif
1848 
1849 PNG_INTERNAL_FUNCTION(void,png_chunk_report,(png_const_structrp png_ptr,
1850    png_const_charp message, int error),PNG_EMPTY);
1851    /* Report a recoverable issue in chunk data.  On read this is used to report
1852     * a problem found while reading a particular chunk and the
1853     * png_chunk_benign_error or png_chunk_warning function is used as
1854     * appropriate.  On write this is used to report an error that comes from
1855     * data set via an application call to a png_set_ API and png_app_error or
1856     * png_app_warning is used as appropriate.
1857     *
1858     * The 'error' parameter must have one of the following values:
1859     */
1860 #define PNG_CHUNK_WARNING     0 /* never an error */
1861 #define PNG_CHUNK_WRITE_ERROR 1 /* an error only on write */
1862 #define PNG_CHUNK_ERROR       2 /* always an error */
1863 
1864 /* ASCII to FP interfaces, currently only implemented if sCAL
1865  * support is required.
1866  */
1867 #if defined(PNG_sCAL_SUPPORTED)
1868 /* MAX_DIGITS is actually the maximum number of characters in an sCAL
1869  * width or height, derived from the precision (number of significant
1870  * digits - a build time settable option) and assumptions about the
1871  * maximum ridiculous exponent.
1872  */
1873 #define PNG_sCAL_MAX_DIGITS (PNG_sCAL_PRECISION+1/*.*/+1/*E*/+10/*exponent*/)
1874 
1875 #ifdef PNG_FLOATING_POINT_SUPPORTED
1876 PNG_INTERNAL_FUNCTION(void,png_ascii_from_fp,(png_const_structrp png_ptr,
1877    png_charp ascii, size_t size, double fp, unsigned int precision),
1878    PNG_EMPTY);
1879 #endif /* FLOATING_POINT */
1880 
1881 #ifdef PNG_FIXED_POINT_SUPPORTED
1882 PNG_INTERNAL_FUNCTION(void,png_ascii_from_fixed,(png_const_structrp png_ptr,
1883    png_charp ascii, size_t size, png_fixed_point fp),PNG_EMPTY);
1884 #endif /* FIXED_POINT */
1885 #endif /* sCAL */
1886 
1887 #if defined(PNG_sCAL_SUPPORTED) || defined(PNG_pCAL_SUPPORTED)
1888 /* An internal API to validate the format of a floating point number.
1889  * The result is the index of the next character.  If the number is
1890  * not valid it will be the index of a character in the supposed number.
1891  *
1892  * The format of a number is defined in the PNG extensions specification
1893  * and this API is strictly conformant to that spec, not anyone elses!
1894  *
1895  * The format as a regular expression is:
1896  *
1897  * [+-]?[0-9]+.?([Ee][+-]?[0-9]+)?
1898  *
1899  * or:
1900  *
1901  * [+-]?.[0-9]+(.[0-9]+)?([Ee][+-]?[0-9]+)?
1902  *
1903  * The complexity is that either integer or fraction must be present and the
1904  * fraction is permitted to have no digits only if the integer is present.
1905  *
1906  * NOTE: The dangling E problem.
1907  *   There is a PNG valid floating point number in the following:
1908  *
1909  *       PNG floating point numbers are not greedy.
1910  *
1911  *   Working this out requires *TWO* character lookahead (because of the
1912  *   sign), the parser does not do this - it will fail at the 'r' - this
1913  *   doesn't matter for PNG sCAL chunk values, but it requires more care
1914  *   if the value were ever to be embedded in something more complex.  Use
1915  *   ANSI-C strtod if you need the lookahead.
1916  */
1917 /* State table for the parser. */
1918 #define PNG_FP_INTEGER    0  /* before or in integer */
1919 #define PNG_FP_FRACTION   1  /* before or in fraction */
1920 #define PNG_FP_EXPONENT   2  /* before or in exponent */
1921 #define PNG_FP_STATE      3  /* mask for the above */
1922 #define PNG_FP_SAW_SIGN   4  /* Saw +/- in current state */
1923 #define PNG_FP_SAW_DIGIT  8  /* Saw a digit in current state */
1924 #define PNG_FP_SAW_DOT   16  /* Saw a dot in current state */
1925 #define PNG_FP_SAW_E     32  /* Saw an E (or e) in current state */
1926 #define PNG_FP_SAW_ANY   60  /* Saw any of the above 4 */
1927 
1928 /* These three values don't affect the parser.  They are set but not used.
1929  */
1930 #define PNG_FP_WAS_VALID 64  /* Preceding substring is a valid fp number */
1931 #define PNG_FP_NEGATIVE 128  /* A negative number, including "-0" */
1932 #define PNG_FP_NONZERO  256  /* A non-zero value */
1933 #define PNG_FP_STICKY   448  /* The above three flags */
1934 
1935 /* This is available for the caller to store in 'state' if required.  Do not
1936  * call the parser after setting it (the parser sometimes clears it.)
1937  */
1938 #define PNG_FP_INVALID  512  /* Available for callers as a distinct value */
1939 
1940 /* Result codes for the parser (boolean - true means ok, false means
1941  * not ok yet.)
1942  */
1943 #define PNG_FP_MAYBE      0  /* The number may be valid in the future */
1944 #define PNG_FP_OK         1  /* The number is valid */
1945 
1946 /* Tests on the sticky non-zero and negative flags.  To pass these checks
1947  * the state must also indicate that the whole number is valid - this is
1948  * achieved by testing PNG_FP_SAW_DIGIT (see the implementation for why this
1949  * is equivalent to PNG_FP_OK above.)
1950  */
1951 #define PNG_FP_NZ_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NEGATIVE | PNG_FP_NONZERO)
1952    /* NZ_MASK: the string is valid and a non-zero negative value */
1953 #define PNG_FP_Z_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NONZERO)
1954    /* Z MASK: the string is valid and a non-zero value. */
1955    /* PNG_FP_SAW_DIGIT: the string is valid. */
1956 #define PNG_FP_IS_ZERO(state) (((state) & PNG_FP_Z_MASK) == PNG_FP_SAW_DIGIT)
1957 #define PNG_FP_IS_POSITIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_Z_MASK)
1958 #define PNG_FP_IS_NEGATIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_NZ_MASK)
1959 
1960 /* The actual parser.  This can be called repeatedly. It updates
1961  * the index into the string and the state variable (which must
1962  * be initialized to 0).  It returns a result code, as above.  There
1963  * is no point calling the parser any more if it fails to advance to
1964  * the end of the string - it is stuck on an invalid character (or
1965  * terminated by '\0').
1966  *
1967  * Note that the pointer will consume an E or even an E+ and then leave
1968  * a 'maybe' state even though a preceding integer.fraction is valid.
1969  * The PNG_FP_WAS_VALID flag indicates that a preceding substring was
1970  * a valid number.  It's possible to recover from this by calling
1971  * the parser again (from the start, with state 0) but with a string
1972  * that omits the last character (i.e. set the size to the index of
1973  * the problem character.)  This has not been tested within libpng.
1974  */
1975 PNG_INTERNAL_FUNCTION(int,png_check_fp_number,(png_const_charp string,
1976    size_t size, int *statep, size_t *whereami),PNG_EMPTY);
1977 
1978 /* This is the same but it checks a complete string and returns true
1979  * only if it just contains a floating point number.  As of 1.5.4 this
1980  * function also returns the state at the end of parsing the number if
1981  * it was valid (otherwise it returns 0.)  This can be used for testing
1982  * for negative or zero values using the sticky flag.
1983  */
1984 PNG_INTERNAL_FUNCTION(int,png_check_fp_string,(png_const_charp string,
1985    size_t size),PNG_EMPTY);
1986 #endif /* pCAL || sCAL */
1987 
1988 #if defined(PNG_GAMMA_SUPPORTED) ||\
1989     defined(PNG_INCH_CONVERSIONS_SUPPORTED) || defined(PNG_READ_pHYs_SUPPORTED)
1990 /* Added at libpng version 1.5.0 */
1991 /* This is a utility to provide a*times/div (rounded) and indicate
1992  * if there is an overflow.  The result is a boolean - false (0)
1993  * for overflow, true (1) if no overflow, in which case *res
1994  * holds the result.
1995  */
1996 PNG_INTERNAL_FUNCTION(int,png_muldiv,(png_fixed_point_p res, png_fixed_point a,
1997    png_int_32 multiplied_by, png_int_32 divided_by),PNG_EMPTY);
1998 #endif
1999 
2000 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_INCH_CONVERSIONS_SUPPORTED)
2001 /* Same deal, but issue a warning on overflow and return 0. */
2002 PNG_INTERNAL_FUNCTION(png_fixed_point,png_muldiv_warn,
2003    (png_const_structrp png_ptr, png_fixed_point a, png_int_32 multiplied_by,
2004    png_int_32 divided_by),PNG_EMPTY);
2005 #endif
2006 
2007 #ifdef PNG_GAMMA_SUPPORTED
2008 /* Calculate a reciprocal - used for gamma values.  This returns
2009  * 0 if the argument is 0 in order to maintain an undefined value;
2010  * there are no warnings.
2011  */
2012 PNG_INTERNAL_FUNCTION(png_fixed_point,png_reciprocal,(png_fixed_point a),
2013    PNG_EMPTY);
2014 
2015 #ifdef PNG_READ_GAMMA_SUPPORTED
2016 /* The same but gives a reciprocal of the product of two fixed point
2017  * values.  Accuracy is suitable for gamma calculations but this is
2018  * not exact - use png_muldiv for that.  Only required at present on read.
2019  */
2020 PNG_INTERNAL_FUNCTION(png_fixed_point,png_reciprocal2,(png_fixed_point a,
2021    png_fixed_point b),PNG_EMPTY);
2022 #endif
2023 
2024 /* Return true if the gamma value is significantly different from 1.0 */
2025 PNG_INTERNAL_FUNCTION(int,png_gamma_significant,(png_fixed_point gamma_value),
2026    PNG_EMPTY);
2027 #endif
2028 
2029 #ifdef PNG_READ_GAMMA_SUPPORTED
2030 /* Internal fixed point gamma correction.  These APIs are called as
2031  * required to convert single values - they don't need to be fast,
2032  * they are not used when processing image pixel values.
2033  *
2034  * While the input is an 'unsigned' value it must actually be the
2035  * correct bit value - 0..255 or 0..65535 as required.
2036  */
2037 PNG_INTERNAL_FUNCTION(png_uint_16,png_gamma_correct,(png_structrp png_ptr,
2038    unsigned int value, png_fixed_point gamma_value),PNG_EMPTY);
2039 PNG_INTERNAL_FUNCTION(png_uint_16,png_gamma_16bit_correct,(unsigned int value,
2040    png_fixed_point gamma_value),PNG_EMPTY);
2041 PNG_INTERNAL_FUNCTION(png_byte,png_gamma_8bit_correct,(unsigned int value,
2042    png_fixed_point gamma_value),PNG_EMPTY);
2043 PNG_INTERNAL_FUNCTION(void,png_destroy_gamma_table,(png_structrp png_ptr),
2044    PNG_EMPTY);
2045 PNG_INTERNAL_FUNCTION(void,png_build_gamma_table,(png_structrp png_ptr,
2046    int bit_depth),PNG_EMPTY);
2047 #endif
2048 
2049 /* SIMPLIFIED READ/WRITE SUPPORT */
2050 #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
2051    defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
2052 /* The internal structure that png_image::opaque points to. */
2053 typedef struct png_control
2054 {
2055    png_structp png_ptr;
2056    png_infop   info_ptr;
2057    png_voidp   error_buf;           /* Always a jmp_buf at present. */
2058 
2059    png_const_bytep memory;          /* Memory buffer. */
2060    size_t          size;            /* Size of the memory buffer. */
2061 
2062    unsigned int for_write       :1; /* Otherwise it is a read structure */
2063    unsigned int owned_file      :1; /* We own the file in io_ptr */
2064 } png_control;
2065 
2066 /* Return the pointer to the jmp_buf from a png_control: necessary because C
2067  * does not reveal the type of the elements of jmp_buf.
2068  */
2069 #ifdef __cplusplus
2070 #  define png_control_jmp_buf(pc) (((jmp_buf*)((pc)->error_buf))[0])
2071 #else
2072 #  define png_control_jmp_buf(pc) ((pc)->error_buf)
2073 #endif
2074 
2075 /* Utility to safely execute a piece of libpng code catching and logging any
2076  * errors that might occur.  Returns true on success, false on failure (either
2077  * of the function or as a result of a png_error.)
2078  */
2079 PNG_INTERNAL_CALLBACK(void,png_safe_error,(png_structp png_ptr,
2080    png_const_charp error_message),PNG_NORETURN);
2081 
2082 #ifdef PNG_WARNINGS_SUPPORTED
2083 PNG_INTERNAL_CALLBACK(void,png_safe_warning,(png_structp png_ptr,
2084    png_const_charp warning_message),PNG_EMPTY);
2085 #else
2086 #  define png_safe_warning 0/*dummy argument*/
2087 #endif
2088 
2089 PNG_INTERNAL_FUNCTION(int,png_safe_execute,(png_imagep image,
2090    int (*function)(png_voidp), png_voidp arg),PNG_EMPTY);
2091 
2092 /* Utility to log an error; this also cleans up the png_image; the function
2093  * always returns 0 (false).
2094  */
2095 PNG_INTERNAL_FUNCTION(int,png_image_error,(png_imagep image,
2096    png_const_charp error_message),PNG_EMPTY);
2097 
2098 #ifndef PNG_SIMPLIFIED_READ_SUPPORTED
2099 /* png_image_free is used by the write code but not exported */
2100 PNG_INTERNAL_FUNCTION(void, png_image_free, (png_imagep image), PNG_EMPTY);
2101 #endif /* !SIMPLIFIED_READ */
2102 
2103 #endif /* SIMPLIFIED READ/WRITE */
2104 
2105 /* These are initialization functions for hardware specific PNG filter
2106  * optimizations; list these here then select the appropriate one at compile
2107  * time using the macro PNG_FILTER_OPTIMIZATIONS.  If the macro is not defined
2108  * the generic code is used.
2109  */
2110 #ifdef PNG_FILTER_OPTIMIZATIONS
2111 PNG_INTERNAL_FUNCTION(void, PNG_FILTER_OPTIMIZATIONS, (png_structp png_ptr,
2112    unsigned int bpp), PNG_EMPTY);
2113    /* Just declare the optimization that will be used */
2114 #else
2115    /* List *all* the possible optimizations here - this branch is required if
2116     * the builder of libpng passes the definition of PNG_FILTER_OPTIMIZATIONS in
2117     * CFLAGS in place of CPPFLAGS *and* uses symbol prefixing.
2118     */
2119 #  if PNG_ARM_NEON_OPT > 0
2120 PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_neon,
2121    (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
2122 #endif
2123 
2124 #if PNG_MIPS_MSA_IMPLEMENTATION == 1
2125 PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_mips,
2126    (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
2127 #endif
2128 
2129 #  if PNG_MIPS_MMI_IMPLEMENTATION > 0
2130 PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_mips,
2131    (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
2132 #  endif
2133 
2134 #  if PNG_INTEL_SSE_IMPLEMENTATION > 0
2135 PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_sse2,
2136    (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
2137 #  endif
2138 #endif
2139 
2140 #if PNG_LOONGARCH_LSX_OPT > 0
2141 PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_lsx,
2142     (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
2143 #endif
2144 
2145 PNG_INTERNAL_FUNCTION(png_uint_32, png_check_keyword, (png_structrp png_ptr,
2146    png_const_charp key, png_bytep new_key), PNG_EMPTY);
2147 
2148 #if PNG_ARM_NEON_IMPLEMENTATION == 1
2149 PNG_INTERNAL_FUNCTION(void,
2150                       png_riffle_palette_neon,
2151                       (png_structrp),
2152                       PNG_EMPTY);
2153 PNG_INTERNAL_FUNCTION(int,
2154                       png_do_expand_palette_rgba8_neon,
2155                       (png_structrp,
2156                        png_row_infop,
2157                        png_const_bytep,
2158                        const png_bytepp,
2159                        const png_bytepp),
2160                       PNG_EMPTY);
2161 PNG_INTERNAL_FUNCTION(int,
2162                       png_do_expand_palette_rgb8_neon,
2163                       (png_structrp,
2164                        png_row_infop,
2165                        png_const_bytep,
2166                        const png_bytepp,
2167                        const png_bytepp),
2168                       PNG_EMPTY);
2169 #endif
2170 
2171 /* Maintainer: Put new private prototypes here ^ */
2172 
2173 #include "pngdebug.h"
2174 
2175 #ifdef __cplusplus
2176 }
2177 #endif
2178 
2179 #endif /* PNG_VERSION_INFO_ONLY */
2180 #endif /* PNGPRIV_H */
2181