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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 
144    /* By default the 'intrinsics' code in arm/filter_neon_intrinsics.c is used
145     * if possible - if __ARM_NEON__ is set and the compiler version is not known
146     * to be broken.  This is controlled by PNG_ARM_NEON_IMPLEMENTATION which can
147     * be:
148     *
149     *    1  The intrinsics code (the default with __ARM_NEON__)
150     *    2  The hand coded assembler (the default without __ARM_NEON__)
151     *
152     * It is possible to set PNG_ARM_NEON_IMPLEMENTATION in CPPFLAGS, however
153     * this is *NOT* supported and may cease to work even after a minor revision
154     * to libpng.  It *is* valid to do this for testing purposes, e.g. speed
155     * testing or a new compiler, but the results should be communicated to the
156     * libpng implementation list for incorporation in the next minor release.
157     */
158 #  ifndef PNG_ARM_NEON_IMPLEMENTATION
159 #     if defined(__ARM_NEON__) || defined(__ARM_NEON)
160 #        if defined(__clang__)
161             /* At present it is unknown by the libpng developers which versions
162              * of clang support the intrinsics, however some or perhaps all
163              * versions do not work with the assembler so this may be
164              * irrelevant, so just use the default (do nothing here.)
165              */
166 #        elif defined(__GNUC__)
167             /* GCC 4.5.4 NEON support is known to be broken.  4.6.3 is known to
168              * work, so if this *is* GCC, or G++, look for a version >4.5
169              */
170 #           if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 6)
171 #              define PNG_ARM_NEON_IMPLEMENTATION 2
172 #           endif /* no GNUC support */
173 #        endif /* __GNUC__ */
174 #     else /* !defined __ARM_NEON__ */
175          /* The 'intrinsics' code simply won't compile without this -mfpu=neon:
176           */
177 #        if !defined(__aarch64__) && !defined(_M_ARM64)
178             /* The assembler code currently does not work on ARM64 */
179 #          define PNG_ARM_NEON_IMPLEMENTATION 2
180 #        endif /* __aarch64__ */
181 #     endif /* __ARM_NEON__ */
182 #  endif /* !PNG_ARM_NEON_IMPLEMENTATION */
183 
184 #  ifndef PNG_ARM_NEON_IMPLEMENTATION
185       /* Use the intrinsics code by default. */
186 #     define PNG_ARM_NEON_IMPLEMENTATION 1
187 #  endif
188 #else /* PNG_ARM_NEON_OPT == 0 */
189 #     define PNG_ARM_NEON_IMPLEMENTATION 0
190 #endif /* PNG_ARM_NEON_OPT > 0 */
191 
192 #ifndef PNG_MIPS_MSA_OPT
193 #  if defined(__mips_msa) && (__mips_isa_rev >= 5) && \
194    defined(PNG_ALIGNED_MEMORY_SUPPORTED)
195 #     define PNG_MIPS_MSA_OPT 2
196 #  else
197 #     define PNG_MIPS_MSA_OPT 0
198 #  endif
199 #endif
200 
201 #ifndef PNG_MIPS_MMI_OPT
202 #  ifdef PNG_MIPS_MMI
203 #    if defined(__mips_loongson_mmi) && (_MIPS_SIM == _ABI64) && \
204      defined(PNG_ALIGNED_MEMORY_SUPPORTED)
205 #       define PNG_MIPS_MMI_OPT 1
206 #    else
207 #       define PNG_MIPS_MMI_OPT 0
208 #    endif
209 #  else
210 #    define PNG_MIPS_MMI_OPT 0
211 #  endif
212 #endif
213 
214 #ifndef PNG_POWERPC_VSX_OPT
215 #  if defined(__PPC64__) && defined(__ALTIVEC__) && defined(__VSX__)
216 #     define PNG_POWERPC_VSX_OPT 2
217 #  else
218 #     define PNG_POWERPC_VSX_OPT 0
219 #  endif
220 #endif
221 
222 #ifndef PNG_LOONGARCH_LSX_OPT
223 #  if defined(__loongarch_sx)
224 #     define PNG_LOONGARCH_LSX_OPT 1
225 #  else
226 #     define PNG_LOONGARCH_LSX_OPT 0
227 #  endif
228 #endif
229 
230 #ifndef PNG_INTEL_SSE_OPT
231 #   ifdef PNG_INTEL_SSE
232       /* Only check for SSE if the build configuration has been modified to
233        * enable SSE optimizations.  This means that these optimizations will
234        * be off by default.  See contrib/intel for more details.
235        */
236 #      if defined(__SSE4_1__) || defined(__AVX__) || defined(__SSSE3__) || \
237        defined(__SSE2__) || defined(_M_X64) || defined(_M_AMD64) || \
238        (defined(_M_IX86_FP) && _M_IX86_FP >= 2)
239 #         define PNG_INTEL_SSE_OPT 1
240 #      else
241 #         define PNG_INTEL_SSE_OPT 0
242 #      endif
243 #   else
244 #      define PNG_INTEL_SSE_OPT 0
245 #   endif
246 #endif
247 
248 #if PNG_INTEL_SSE_OPT > 0
249 #   ifndef PNG_INTEL_SSE_IMPLEMENTATION
250 #      if defined(__SSE4_1__) || defined(__AVX__)
251           /* We are not actually using AVX, but checking for AVX is the best
252              way we can detect SSE4.1 and SSSE3 on MSVC.
253           */
254 #         define PNG_INTEL_SSE_IMPLEMENTATION 3
255 #      elif defined(__SSSE3__)
256 #         define PNG_INTEL_SSE_IMPLEMENTATION 2
257 #      elif defined(__SSE2__) || defined(_M_X64) || defined(_M_AMD64) || \
258        (defined(_M_IX86_FP) && _M_IX86_FP >= 2)
259 #         define PNG_INTEL_SSE_IMPLEMENTATION 1
260 #      else
261 #         define PNG_INTEL_SSE_IMPLEMENTATION 0
262 #      endif
263 #   endif
264 
265 #   if PNG_INTEL_SSE_IMPLEMENTATION > 0
266 #      define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_sse2
267 #   endif
268 #else
269 #   define PNG_INTEL_SSE_IMPLEMENTATION 0
270 #endif
271 
272 #if PNG_MIPS_MSA_OPT > 0
273 #  ifndef PNG_MIPS_MSA_IMPLEMENTATION
274 #     if defined(__mips_msa)
275 #        if defined(__clang__)
276 #        elif defined(__GNUC__)
277 #           if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 7)
278 #              define PNG_MIPS_MSA_IMPLEMENTATION 2
279 #           endif /* no GNUC support */
280 #        endif /* __GNUC__ */
281 #     else /* !defined __mips_msa */
282 #        define PNG_MIPS_MSA_IMPLEMENTATION 2
283 #     endif /* __mips_msa */
284 #  endif /* !PNG_MIPS_MSA_IMPLEMENTATION */
285 
286 #  ifndef PNG_MIPS_MSA_IMPLEMENTATION
287 #     define PNG_MIPS_MSA_IMPLEMENTATION 1
288 #     define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_mips
289 #  endif
290 #else
291 #  define PNG_MIPS_MSA_IMPLEMENTATION 0
292 #endif /* PNG_MIPS_MSA_OPT > 0 */
293 
294 #if PNG_MIPS_MMI_OPT > 0
295 #  ifndef PNG_MIPS_MMI_IMPLEMENTATION
296 #     if defined(__mips_loongson_mmi) && (_MIPS_SIM == _ABI64)
297 #        define PNG_MIPS_MMI_IMPLEMENTATION 2
298 #     else /* !defined __mips_loongson_mmi  || _MIPS_SIM != _ABI64 */
299 #        define PNG_MIPS_MMI_IMPLEMENTATION 0
300 #     endif /* __mips_loongson_mmi  && _MIPS_SIM == _ABI64 */
301 #  endif /* !PNG_MIPS_MMI_IMPLEMENTATION */
302 
303 #   if PNG_MIPS_MMI_IMPLEMENTATION > 0
304 #      define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_mips
305 #   endif
306 #else
307 #   define PNG_MIPS_MMI_IMPLEMENTATION 0
308 #endif /* PNG_MIPS_MMI_OPT > 0 */
309 
310 #if PNG_POWERPC_VSX_OPT > 0
311 #  define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_vsx
312 #  define PNG_POWERPC_VSX_IMPLEMENTATION 1
313 #else
314 #  define PNG_POWERPC_VSX_IMPLEMENTATION 0
315 #endif
316 
317 #if PNG_LOONGARCH_LSX_OPT > 0
318 #   define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_lsx
319 #   define PNG_LOONGARCH_LSX_IMPLEMENTATION 1
320 #else
321 #   define PNG_LOONGARCH_LSX_IMPLEMENTATION 0
322 #endif
323 
324 /* Is this a build of a DLL where compilation of the object modules requires
325  * different preprocessor settings to those required for a simple library?  If
326  * so PNG_BUILD_DLL must be set.
327  *
328  * If libpng is used inside a DLL but that DLL does not export the libpng APIs
329  * PNG_BUILD_DLL must not be set.  To avoid the code below kicking in build a
330  * static library of libpng then link the DLL against that.
331  */
332 #ifndef PNG_BUILD_DLL
333 #  ifdef DLL_EXPORT
334       /* This is set by libtool when files are compiled for a DLL; libtool
335        * always compiles twice, even on systems where it isn't necessary.  Set
336        * PNG_BUILD_DLL in case it is necessary:
337        */
338 #     define PNG_BUILD_DLL
339 #  else
340 #     ifdef _WINDLL
341          /* This is set by the Microsoft Visual Studio IDE in projects that
342           * build a DLL.  It can't easily be removed from those projects (it
343           * isn't visible in the Visual Studio UI) so it is a fairly reliable
344           * indication that PNG_IMPEXP needs to be set to the DLL export
345           * attributes.
346           */
347 #        define PNG_BUILD_DLL
348 #     else
349 #        ifdef __DLL__
350             /* This is set by the Borland C system when compiling for a DLL
351              * (as above.)
352              */
353 #           define PNG_BUILD_DLL
354 #        else
355             /* Add additional compiler cases here. */
356 #        endif
357 #     endif
358 #  endif
359 #endif /* Setting PNG_BUILD_DLL if required */
360 
361 /* See pngconf.h for more details: the builder of the library may set this on
362  * the command line to the right thing for the specific compilation system or it
363  * may be automagically set above (at present we know of no system where it does
364  * need to be set on the command line.)
365  *
366  * PNG_IMPEXP must be set here when building the library to prevent pngconf.h
367  * setting it to the "import" setting for a DLL build.
368  */
369 #ifndef PNG_IMPEXP
370 #  ifdef PNG_BUILD_DLL
371 #     define PNG_IMPEXP PNG_DLL_EXPORT
372 #  else
373       /* Not building a DLL, or the DLL doesn't require specific export
374        * definitions.
375        */
376 #     define PNG_IMPEXP
377 #  endif
378 #endif
379 
380 /* No warnings for private or deprecated functions in the build: */
381 #ifndef PNG_DEPRECATED
382 #  define PNG_DEPRECATED
383 #endif
384 #ifndef PNG_PRIVATE
385 #  define PNG_PRIVATE
386 #endif
387 
388 /* Symbol preprocessing support.
389  *
390  * To enable listing global, but internal, symbols the following macros should
391  * always be used to declare an extern data or function object in this file.
392  */
393 #ifndef PNG_INTERNAL_DATA
394 #  define PNG_INTERNAL_DATA(type, name, array) PNG_LINKAGE_DATA type name array
395 #endif
396 
397 #ifndef PNG_INTERNAL_FUNCTION
398 #  define PNG_INTERNAL_FUNCTION(type, name, args, attributes)\
399       PNG_LINKAGE_FUNCTION PNG_FUNCTION(type, name, args, PNG_EMPTY attributes)
400 #endif
401 
402 #ifndef PNG_INTERNAL_CALLBACK
403 #  define PNG_INTERNAL_CALLBACK(type, name, args, attributes)\
404       PNG_LINKAGE_CALLBACK PNG_FUNCTION(type, (PNGCBAPI name), args,\
405          PNG_EMPTY attributes)
406 #endif
407 
408 /* If floating or fixed point APIs are disabled they may still be compiled
409  * internally.  To handle this make sure they are declared as the appropriate
410  * internal extern function (otherwise the symbol prefixing stuff won't work and
411  * the functions will be used without definitions.)
412  *
413  * NOTE: although all the API functions are declared here they are not all
414  * actually built!  Because the declarations are still made it is necessary to
415  * fake out types that they depend on.
416  */
417 #ifndef PNG_FP_EXPORT
418 #  ifndef PNG_FLOATING_POINT_SUPPORTED
419 #     define PNG_FP_EXPORT(ordinal, type, name, args)\
420          PNG_INTERNAL_FUNCTION(type, name, args, PNG_EMPTY);
421 #     ifndef PNG_VERSION_INFO_ONLY
422          typedef struct png_incomplete png_double;
423          typedef png_double*           png_doublep;
424          typedef const png_double*     png_const_doublep;
425          typedef png_double**          png_doublepp;
426 #     endif
427 #  endif
428 #endif
429 #ifndef PNG_FIXED_EXPORT
430 #  ifndef PNG_FIXED_POINT_SUPPORTED
431 #     define PNG_FIXED_EXPORT(ordinal, type, name, args)\
432          PNG_INTERNAL_FUNCTION(type, name, args, PNG_EMPTY);
433 #  endif
434 #endif
435 
436 #include "png.h"
437 
438 /* pngconf.h does not set PNG_DLL_EXPORT unless it is required, so: */
439 #ifndef PNG_DLL_EXPORT
440 #  define PNG_DLL_EXPORT
441 #endif
442 
443 /* This is a global switch to set the compilation for an installed system
444  * (a release build).  It can be set for testing debug builds to ensure that
445  * they will compile when the build type is switched to RC or STABLE, the
446  * default is just to use PNG_LIBPNG_BUILD_BASE_TYPE.  Set this in CPPFLAGS
447  * with either:
448  *
449  *   -DPNG_RELEASE_BUILD Turns on the release compile path
450  *   -DPNG_RELEASE_BUILD=0 Turns it off
451  * or in your pngusr.h with
452  *   #define PNG_RELEASE_BUILD=1 Turns on the release compile path
453  *   #define PNG_RELEASE_BUILD=0 Turns it off
454  */
455 #ifndef PNG_RELEASE_BUILD
456 #  define PNG_RELEASE_BUILD (PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC)
457 #endif
458 
459 /* SECURITY and SAFETY:
460  *
461  * libpng is built with support for internal limits on image dimensions and
462  * memory usage.  These are documented in scripts/pnglibconf.dfa of the
463  * source and recorded in the machine generated header file pnglibconf.h.
464  */
465 
466 /* If you are running on a machine where you cannot allocate more
467  * than 64K of memory at once, uncomment this.  While libpng will not
468  * normally need that much memory in a chunk (unless you load up a very
469  * large file), zlib needs to know how big of a chunk it can use, and
470  * libpng thus makes sure to check any memory allocation to verify it
471  * will fit into memory.
472  *
473  * zlib provides 'MAXSEG_64K' which, if defined, indicates the
474  * same limit and pngconf.h (already included) sets the limit
475  * if certain operating systems are detected.
476  */
477 #if defined(MAXSEG_64K) && !defined(PNG_MAX_MALLOC_64K)
478 #  define PNG_MAX_MALLOC_64K
479 #endif
480 
481 #ifndef PNG_UNUSED
482 /* Unused formal parameter warnings are silenced using the following macro
483  * which is expected to have no bad effects on performance (optimizing
484  * compilers will probably remove it entirely).  Note that if you replace
485  * it with something other than whitespace, you must include the terminating
486  * semicolon.
487  */
488 #  define PNG_UNUSED(param) (void)param;
489 #endif
490 
491 /* Just a little check that someone hasn't tried to define something
492  * contradictory.
493  */
494 #if (PNG_ZBUF_SIZE > 65536L) && defined(PNG_MAX_MALLOC_64K)
495 #  undef PNG_ZBUF_SIZE
496 #  define PNG_ZBUF_SIZE 65536L
497 #endif
498 
499 /* If warnings or errors are turned off the code is disabled or redirected here.
500  * From 1.5.4 functions have been added to allow very limited formatting of
501  * error and warning messages - this code will also be disabled here.
502  */
503 #ifdef PNG_WARNINGS_SUPPORTED
504 #  define PNG_WARNING_PARAMETERS(p) png_warning_parameters p;
505 #else
506 #  define png_warning_parameter(p,number,string) ((void)0)
507 #  define png_warning_parameter_unsigned(p,number,format,value) ((void)0)
508 #  define png_warning_parameter_signed(p,number,format,value) ((void)0)
509 #  define png_formatted_warning(pp,p,message) ((void)(pp))
510 #  define PNG_WARNING_PARAMETERS(p)
511 #endif
512 #ifndef PNG_ERROR_TEXT_SUPPORTED
513 #  define png_fixed_error(s1,s2) png_err(s1)
514 #endif
515 
516 /* Some fixed point APIs are still required even if not exported because
517  * they get used by the corresponding floating point APIs.  This magic
518  * deals with this:
519  */
520 #ifdef PNG_FIXED_POINT_SUPPORTED
521 #  define PNGFAPI PNGAPI
522 #else
523 #  define PNGFAPI /* PRIVATE */
524 #endif
525 
526 #ifndef PNG_VERSION_INFO_ONLY
527 /* Other defines specific to compilers can go here.  Try to keep
528  * them inside an appropriate ifdef/endif pair for portability.
529  */
530 
531 /* C allows up-casts from (void*) to any pointer and (const void*) to any
532  * pointer to a const object.  C++ regards this as a type error and requires an
533  * explicit, static, cast and provides the static_cast<> rune to ensure that
534  * const is not cast away.
535  */
536 #ifdef __cplusplus
537 #  define png_voidcast(type, value) static_cast<type>(value)
538 #  define png_constcast(type, value) const_cast<type>(value)
539 #  define png_aligncast(type, value) \
540    static_cast<type>(static_cast<void*>(value))
541 #  define png_aligncastconst(type, value) \
542    static_cast<type>(static_cast<const void*>(value))
543 #else
544 #  define png_voidcast(type, value) (value)
545 #  define png_constcast(type, value) ((type)(void*)(const void*)(value))
546 #  define png_aligncast(type, value) ((void*)(value))
547 #  define png_aligncastconst(type, value) ((const void*)(value))
548 #endif /* __cplusplus */
549 
550 #if defined(PNG_FLOATING_POINT_SUPPORTED) ||\
551     defined(PNG_FLOATING_ARITHMETIC_SUPPORTED)
552    /* png.c requires the following ANSI-C constants if the conversion of
553     * floating point to ASCII is implemented therein:
554     *
555     *  DBL_DIG  Maximum number of decimal digits (can be set to any constant)
556     *  DBL_MIN  Smallest normalized fp number (can be set to an arbitrary value)
557     *  DBL_MAX  Maximum floating point number (can be set to an arbitrary value)
558     */
559 #  include <float.h>
560 
561 #  include <math.h>
562 
563 #  if defined(_AMIGA) && defined(__SASC) && defined(_M68881)
564    /* Amiga SAS/C: We must include builtin FPU functions when compiling using
565     * MATH=68881
566     */
567 #    include <m68881.h>
568 #  endif
569 #endif
570 
571 /* This provides the non-ANSI (far) memory allocation routines. */
572 #if defined(__TURBOC__) && defined(__MSDOS__)
573 #  include <mem.h>
574 #  include <alloc.h>
575 #endif
576 
577 #if defined(_WIN32) || defined(__WIN32__) || defined(__NT__)
578 #  include <windows.h>
579 #endif
580 #endif /* PNG_VERSION_INFO_ONLY */
581 
582 /* Moved here around 1.5.0beta36 from pngconf.h */
583 /* Users may want to use these so they are not private.  Any library
584  * functions that are passed far data must be model-independent.
585  */
586 
587 /* Platform-independent functions */
588 #ifndef PNG_ABORT
589 #  define PNG_ABORT() abort()
590 #endif
591 
592 /* These macros may need to be architecture dependent. */
593 #define PNG_ALIGN_NONE      0 /* do not use data alignment */
594 #define PNG_ALIGN_ALWAYS    1 /* assume unaligned accesses are OK */
595 #ifdef offsetof
596 #  define PNG_ALIGN_OFFSET  2 /* use offsetof to determine alignment */
597 #else
598 #  define PNG_ALIGN_OFFSET -1 /* prevent the use of this */
599 #endif
600 #define PNG_ALIGN_SIZE      3 /* use sizeof to determine alignment */
601 
602 #ifndef PNG_ALIGN_TYPE
603    /* Default to using aligned access optimizations and requiring alignment to a
604     * multiple of the data type size.  Override in a compiler specific fashion
605     * if necessary by inserting tests here:
606     */
607 #  define PNG_ALIGN_TYPE PNG_ALIGN_SIZE
608 #endif
609 
610 #if PNG_ALIGN_TYPE == PNG_ALIGN_SIZE
611    /* This is used because in some compiler implementations non-aligned
612     * structure members are supported, so the offsetof approach below fails.
613     * Set PNG_ALIGN_SIZE=0 for compiler combinations where unaligned access
614     * is good for performance.  Do not do this unless you have tested the
615     * result and understand it.
616     */
617 #  define png_alignof(type) (sizeof(type))
618 #else
619 #  if PNG_ALIGN_TYPE == PNG_ALIGN_OFFSET
620 #    define png_alignof(type) offsetof(struct{char c; type t;}, t)
621 #  else
622 #    if PNG_ALIGN_TYPE == PNG_ALIGN_ALWAYS
623 #      define png_alignof(type) 1
624 #    endif
625      /* Else leave png_alignof undefined to prevent use thereof */
626 #  endif
627 #endif
628 
629 /* This implicitly assumes alignment is always a multiple of 2. */
630 #ifdef png_alignof
631 #  define png_isaligned(ptr, type) \
632    (((type)(size_t)((const void*)(ptr)) & (type)(png_alignof(type)-1)) == 0)
633 #else
634 #  define png_isaligned(ptr, type) 0
635 #endif
636 
637 /* End of memory model/platform independent support */
638 /* End of 1.5.0beta36 move from pngconf.h */
639 
640 /* CONSTANTS and UTILITY MACROS
641  * These are used internally by libpng and not exposed in the API
642  */
643 
644 /* Various modes of operation.  Note that after an init, mode is set to
645  * zero automatically when the structure is created.  Three of these
646  * are defined in png.h because they need to be visible to applications
647  * that call png_set_unknown_chunk().
648  */
649 /* #define PNG_HAVE_IHDR            0x01U (defined in png.h) */
650 /* #define PNG_HAVE_PLTE            0x02U (defined in png.h) */
651 #define PNG_HAVE_IDAT               0x04U
652 /* #define PNG_AFTER_IDAT           0x08U (defined in png.h) */
653 #define PNG_HAVE_IEND               0x10U
654                    /*               0x20U (unused) */
655                    /*               0x40U (unused) */
656                    /*               0x80U (unused) */
657 #define PNG_HAVE_CHUNK_HEADER      0x100U
658 #define PNG_WROTE_tIME             0x200U
659 #define PNG_WROTE_INFO_BEFORE_PLTE 0x400U
660 #define PNG_BACKGROUND_IS_GRAY     0x800U
661 #define PNG_HAVE_PNG_SIGNATURE    0x1000U
662 #define PNG_HAVE_CHUNK_AFTER_IDAT 0x2000U /* Have another chunk after IDAT */
663 #define PNG_WROTE_eXIf            0x4000U
664 #define PNG_IS_READ_STRUCT        0x8000U /* Else is a write struct */
665 
666 /* Flags for the transformations the PNG library does on the image data */
667 #define PNG_BGR                 0x0001U
668 #define PNG_INTERLACE           0x0002U
669 #define PNG_PACK                0x0004U
670 #define PNG_SHIFT               0x0008U
671 #define PNG_SWAP_BYTES          0x0010U
672 #define PNG_INVERT_MONO         0x0020U
673 #define PNG_QUANTIZE            0x0040U
674 #define PNG_COMPOSE             0x0080U    /* Was PNG_BACKGROUND */
675 #define PNG_BACKGROUND_EXPAND   0x0100U
676 #define PNG_EXPAND_16           0x0200U    /* Added to libpng 1.5.2 */
677 #define PNG_16_TO_8             0x0400U    /* Becomes 'chop' in 1.5.4 */
678 #define PNG_RGBA                0x0800U
679 #define PNG_EXPAND              0x1000U
680 #define PNG_GAMMA               0x2000U
681 #define PNG_GRAY_TO_RGB         0x4000U
682 #define PNG_FILLER              0x8000U
683 #define PNG_PACKSWAP           0x10000U
684 #define PNG_SWAP_ALPHA         0x20000U
685 #define PNG_STRIP_ALPHA        0x40000U
686 #define PNG_INVERT_ALPHA       0x80000U
687 #define PNG_USER_TRANSFORM    0x100000U
688 #define PNG_RGB_TO_GRAY_ERR   0x200000U
689 #define PNG_RGB_TO_GRAY_WARN  0x400000U
690 #define PNG_RGB_TO_GRAY       0x600000U /* two bits, RGB_TO_GRAY_ERR|WARN */
691 #define PNG_ENCODE_ALPHA      0x800000U /* Added to libpng-1.5.4 */
692 #define PNG_ADD_ALPHA        0x1000000U /* Added to libpng-1.2.7 */
693 #define PNG_EXPAND_tRNS      0x2000000U /* Added to libpng-1.2.9 */
694 #define PNG_SCALE_16_TO_8    0x4000000U /* Added to libpng-1.5.4 */
695                        /*    0x8000000U unused */
696                        /*   0x10000000U unused */
697                        /*   0x20000000U unused */
698                        /*   0x40000000U unused */
699 /* Flags for png_create_struct */
700 #define PNG_STRUCT_PNG   0x0001U
701 #define PNG_STRUCT_INFO  0x0002U
702 
703 /* Flags for the png_ptr->flags rather than declaring a byte for each one */
704 #define PNG_FLAG_ZLIB_CUSTOM_STRATEGY     0x0001U
705 #define PNG_FLAG_ZSTREAM_INITIALIZED      0x0002U /* Added to libpng-1.6.0 */
706                                   /*      0x0004U    unused */
707 #define PNG_FLAG_ZSTREAM_ENDED            0x0008U /* Added to libpng-1.6.0 */
708                                   /*      0x0010U    unused */
709                                   /*      0x0020U    unused */
710 #define PNG_FLAG_ROW_INIT                 0x0040U
711 #define PNG_FLAG_FILLER_AFTER             0x0080U
712 #define PNG_FLAG_CRC_ANCILLARY_USE        0x0100U
713 #define PNG_FLAG_CRC_ANCILLARY_NOWARN     0x0200U
714 #define PNG_FLAG_CRC_CRITICAL_USE         0x0400U
715 #define PNG_FLAG_CRC_CRITICAL_IGNORE      0x0800U
716 #define PNG_FLAG_ASSUME_sRGB              0x1000U /* Added to libpng-1.5.4 */
717 #define PNG_FLAG_OPTIMIZE_ALPHA           0x2000U /* Added to libpng-1.5.4 */
718 #define PNG_FLAG_DETECT_UNINITIALIZED     0x4000U /* Added to libpng-1.5.4 */
719 /* #define PNG_FLAG_KEEP_UNKNOWN_CHUNKS      0x8000U */
720 /* #define PNG_FLAG_KEEP_UNSAFE_CHUNKS      0x10000U */
721 #define PNG_FLAG_LIBRARY_MISMATCH        0x20000U
722 #define PNG_FLAG_STRIP_ERROR_NUMBERS     0x40000U
723 #define PNG_FLAG_STRIP_ERROR_TEXT        0x80000U
724 #define PNG_FLAG_BENIGN_ERRORS_WARN     0x100000U /* Added to libpng-1.4.0 */
725 #define PNG_FLAG_APP_WARNINGS_WARN      0x200000U /* Added to libpng-1.6.0 */
726 #define PNG_FLAG_APP_ERRORS_WARN        0x400000U /* Added to libpng-1.6.0 */
727                                   /*    0x800000U    unused */
728                                   /*   0x1000000U    unused */
729                                   /*   0x2000000U    unused */
730                                   /*   0x4000000U    unused */
731                                   /*   0x8000000U    unused */
732                                   /*  0x10000000U    unused */
733                                   /*  0x20000000U    unused */
734                                   /*  0x40000000U    unused */
735 
736 #define PNG_FLAG_CRC_ANCILLARY_MASK (PNG_FLAG_CRC_ANCILLARY_USE | \
737                                      PNG_FLAG_CRC_ANCILLARY_NOWARN)
738 
739 #define PNG_FLAG_CRC_CRITICAL_MASK  (PNG_FLAG_CRC_CRITICAL_USE | \
740                                      PNG_FLAG_CRC_CRITICAL_IGNORE)
741 
742 #define PNG_FLAG_CRC_MASK           (PNG_FLAG_CRC_ANCILLARY_MASK | \
743                                      PNG_FLAG_CRC_CRITICAL_MASK)
744 
745 /* Save typing and make code easier to understand */
746 
747 #define PNG_COLOR_DIST(c1, c2) (abs((int)((c1).red) - (int)((c2).red)) + \
748    abs((int)((c1).green) - (int)((c2).green)) + \
749    abs((int)((c1).blue) - (int)((c2).blue)))
750 
751 /* Added to libpng-1.6.0: scale a 16-bit value in the range 0..65535 to 0..255
752  * by dividing by 257 *with rounding*.  This macro is exact for the given range.
753  * See the discourse in pngrtran.c png_do_scale_16_to_8.  The values in the
754  * macro were established by experiment (modifying the added value).  The macro
755  * has a second variant that takes a value already scaled by 255 and divides by
756  * 65535 - this has a maximum error of .502.  Over the range 0..65535*65535 it
757  * only gives off-by-one errors and only for 0.5% (1 in 200) of the values.
758  */
759 #define PNG_DIV65535(v24) (((v24) + 32895) >> 16)
760 #define PNG_DIV257(v16) PNG_DIV65535((png_uint_32)(v16) * 255)
761 
762 /* Added to libpng-1.2.6 JB */
763 #define PNG_ROWBYTES(pixel_bits, width) \
764     ((pixel_bits) >= 8 ? \
765     ((size_t)(width) * (((size_t)(pixel_bits)) >> 3)) : \
766     (( ((size_t)(width) * ((size_t)(pixel_bits))) + 7) >> 3) )
767 
768 /* This returns the number of trailing bits in the last byte of a row, 0 if the
769  * last byte is completely full of pixels.  It is, in principle, (pixel_bits x
770  * width) % 8, but that would overflow for large 'width'.  The second macro is
771  * the same except that it returns the number of unused bits in the last byte;
772  * (8-TRAILBITS), but 0 when TRAILBITS is 0.
773  *
774  * NOTE: these macros are intended to be self-evidently correct and never
775  * overflow on the assumption that pixel_bits is in the range 0..255.  The
776  * arguments are evaluated only once and they can be signed (e.g. as a result of
777  * the integral promotions).  The result of the expression always has type
778  * (png_uint_32), however the compiler always knows it is in the range 0..7.
779  */
780 #define PNG_TRAILBITS(pixel_bits, width) \
781     (((pixel_bits) * ((width) % (png_uint_32)8)) % 8)
782 
783 #define PNG_PADBITS(pixel_bits, width) \
784     ((8 - PNG_TRAILBITS(pixel_bits, width)) % 8)
785 
786 /* PNG_OUT_OF_RANGE returns true if value is outside the range
787  * ideal-delta..ideal+delta.  Each argument is evaluated twice.
788  * "ideal" and "delta" should be constants, normally simple
789  * integers, "value" a variable. Added to libpng-1.2.6 JB
790  */
791 #define PNG_OUT_OF_RANGE(value, ideal, delta) \
792    ( (value) < (ideal)-(delta) || (value) > (ideal)+(delta) )
793 
794 /* Conversions between fixed and floating point, only defined if
795  * required (to make sure the code doesn't accidentally use float
796  * when it is supposedly disabled.)
797  */
798 #ifdef PNG_FLOATING_POINT_SUPPORTED
799 /* The floating point conversion can't overflow, though it can and
800  * does lose accuracy relative to the original fixed point value.
801  * In practice this doesn't matter because png_fixed_point only
802  * stores numbers with very low precision.  The png_ptr and s
803  * arguments are unused by default but are there in case error
804  * checking becomes a requirement.
805  */
806 #define png_float(png_ptr, fixed, s) (.00001 * (fixed))
807 
808 /* The fixed point conversion performs range checking and evaluates
809  * its argument multiple times, so must be used with care.  The
810  * range checking uses the PNG specification values for a signed
811  * 32-bit fixed point value except that the values are deliberately
812  * rounded-to-zero to an integral value - 21474 (21474.83 is roughly
813  * (2^31-1) * 100000). 's' is a string that describes the value being
814  * converted.
815  *
816  * NOTE: this macro will raise a png_error if the range check fails,
817  * therefore it is normally only appropriate to use this on values
818  * that come from API calls or other sources where an out of range
819  * error indicates a programming error, not a data error!
820  *
821  * NOTE: by default this is off - the macro is not used - because the
822  * function call saves a lot of code.
823  */
824 #ifdef PNG_FIXED_POINT_MACRO_SUPPORTED
825 #define png_fixed(png_ptr, fp, s) ((fp) <= 21474 && (fp) >= -21474 ?\
826     ((png_fixed_point)(100000 * (fp))) : (png_fixed_error(png_ptr, s),0))
827 #endif
828 /* else the corresponding function is defined below, inside the scope of the
829  * cplusplus test.
830  */
831 #endif
832 
833 /* Constants for known chunk types.  If you need to add a chunk, define the name
834  * here.  For historical reasons these constants have the form png_<name>; i.e.
835  * the prefix is lower case.  Please use decimal values as the parameters to
836  * match the ISO PNG specification and to avoid relying on the C locale
837  * interpretation of character values.
838  *
839  * Prior to 1.5.6 these constants were strings, as of 1.5.6 png_uint_32 values
840  * are computed and a new macro (PNG_STRING_FROM_CHUNK) added to allow a string
841  * to be generated if required.
842  *
843  * PNG_32b correctly produces a value shifted by up to 24 bits, even on
844  * architectures where (int) is only 16 bits.
845  */
846 #define PNG_32b(b,s) ((png_uint_32)(b) << (s))
847 #define PNG_U32(b1,b2,b3,b4) \
848    (PNG_32b(b1,24) | PNG_32b(b2,16) | PNG_32b(b3,8) | PNG_32b(b4,0))
849 
850 /* Constants for known chunk types.
851  *
852  * MAINTAINERS: If you need to add a chunk, define the name here.
853  * For historical reasons these constants have the form png_<name>; i.e.
854  * the prefix is lower case.  Please use decimal values as the parameters to
855  * match the ISO PNG specification and to avoid relying on the C locale
856  * interpretation of character values.  Please keep the list sorted.
857  *
858  * Notice that PNG_U32 is used to define a 32-bit value for the 4 byte chunk
859  * type.  In fact the specification does not express chunk types this way,
860  * however using a 32-bit value means that the chunk type can be read from the
861  * stream using exactly the same code as used for a 32-bit unsigned value and
862  * can be examined far more efficiently (using one arithmetic compare).
863  *
864  * Prior to 1.5.6 the chunk type constants were expressed as C strings.  The
865  * libpng API still uses strings for 'unknown' chunks and a macro,
866  * PNG_STRING_FROM_CHUNK, allows a string to be generated if required.  Notice
867  * that for portable code numeric values must still be used; the string "IHDR"
868  * is not portable and neither is PNG_U32('I', 'H', 'D', 'R').
869  *
870  * In 1.7.0 the definitions will be made public in png.h to avoid having to
871  * duplicate the same definitions in application code.
872  */
873 #define png_IDAT PNG_U32( 73,  68,  65,  84)
874 #define png_IEND PNG_U32( 73,  69,  78,  68)
875 #define png_IHDR PNG_U32( 73,  72,  68,  82)
876 #define png_PLTE PNG_U32( 80,  76,  84,  69)
877 #define png_bKGD PNG_U32( 98,  75,  71,  68)
878 #define png_cHRM PNG_U32( 99,  72,  82,  77)
879 #define png_eXIf PNG_U32(101,  88,  73, 102) /* registered July 2017 */
880 #define png_fRAc PNG_U32(102,  82,  65,  99) /* registered, not defined */
881 #define png_gAMA PNG_U32(103,  65,  77,  65)
882 #define png_gIFg PNG_U32(103,  73,  70, 103)
883 #define png_gIFt PNG_U32(103,  73,  70, 116) /* deprecated */
884 #define png_gIFx PNG_U32(103,  73,  70, 120)
885 #define png_hIST PNG_U32(104,  73,  83,  84)
886 #define png_iCCP PNG_U32(105,  67,  67,  80)
887 #define png_iTXt PNG_U32(105,  84,  88, 116)
888 #define png_oFFs PNG_U32(111,  70,  70, 115)
889 #define png_pCAL PNG_U32(112,  67,  65,  76)
890 #define png_pHYs PNG_U32(112,  72,  89, 115)
891 #define png_sBIT PNG_U32(115,  66,  73,  84)
892 #define png_sCAL PNG_U32(115,  67,  65,  76)
893 #define png_sPLT PNG_U32(115,  80,  76,  84)
894 #define png_sRGB PNG_U32(115,  82,  71,  66)
895 #define png_sTER PNG_U32(115,  84,  69,  82)
896 #define png_tEXt PNG_U32(116,  69,  88, 116)
897 #define png_tIME PNG_U32(116,  73,  77,  69)
898 #define png_tRNS PNG_U32(116,  82,  78,  83)
899 #define png_zTXt PNG_U32(122,  84,  88, 116)
900 
901 /* The following will work on (signed char*) strings, whereas the get_uint_32
902  * macro will fail on top-bit-set values because of the sign extension.
903  */
904 #define PNG_CHUNK_FROM_STRING(s)\
905    PNG_U32(0xff & (s)[0], 0xff & (s)[1], 0xff & (s)[2], 0xff & (s)[3])
906 
907 /* This uses (char), not (png_byte) to avoid warnings on systems where (char) is
908  * signed and the argument is a (char[])  This macro will fail miserably on
909  * systems where (char) is more than 8 bits.
910  */
911 #define PNG_STRING_FROM_CHUNK(s,c)\
912    (void)(((char*)(s))[0]=(char)(((c)>>24) & 0xff), \
913    ((char*)(s))[1]=(char)(((c)>>16) & 0xff),\
914    ((char*)(s))[2]=(char)(((c)>>8) & 0xff), \
915    ((char*)(s))[3]=(char)((c & 0xff)))
916 
917 /* Do the same but terminate with a null character. */
918 #define PNG_CSTRING_FROM_CHUNK(s,c)\
919    (void)(PNG_STRING_FROM_CHUNK(s,c), ((char*)(s))[4] = 0)
920 
921 /* Test on flag values as defined in the spec (section 5.4): */
922 #define PNG_CHUNK_ANCILLARY(c)   (1 & ((c) >> 29))
923 #define PNG_CHUNK_CRITICAL(c)     (!PNG_CHUNK_ANCILLARY(c))
924 #define PNG_CHUNK_PRIVATE(c)      (1 & ((c) >> 21))
925 #define PNG_CHUNK_RESERVED(c)     (1 & ((c) >> 13))
926 #define PNG_CHUNK_SAFE_TO_COPY(c) (1 & ((c) >>  5))
927 
928 /* Gamma values (new at libpng-1.5.4): */
929 #define PNG_GAMMA_MAC_OLD 151724  /* Assume '1.8' is really 2.2/1.45! */
930 #define PNG_GAMMA_MAC_INVERSE 65909
931 #define PNG_GAMMA_sRGB_INVERSE 45455
932 
933 /* Almost everything below is C specific; the #defines above can be used in
934  * non-C code (so long as it is C-preprocessed) the rest of this stuff cannot.
935  */
936 #ifndef PNG_VERSION_INFO_ONLY
937 
938 #include "pngstruct.h"
939 #include "pnginfo.h"
940 
941 /* Validate the include paths - the include path used to generate pnglibconf.h
942  * must match that used in the build, or we must be using pnglibconf.h.prebuilt:
943  */
944 #if PNG_ZLIB_VERNUM != 0 && PNG_ZLIB_VERNUM != ZLIB_VERNUM
945 #  error ZLIB_VERNUM != PNG_ZLIB_VERNUM \
946       "-I (include path) error: see the notes in pngpriv.h"
947    /* This means that when pnglibconf.h was built the copy of zlib.h that it
948     * used is not the same as the one being used here.  Because the build of
949     * libpng makes decisions to use inflateInit2 and inflateReset2 based on the
950     * zlib version number and because this affects handling of certain broken
951     * PNG files the -I directives must match.
952     *
953     * The most likely explanation is that you passed a -I in CFLAGS. This will
954     * not work; all the preprocessor directives and in particular all the -I
955     * directives must be in CPPFLAGS.
956     */
957 #endif
958 
959 /* This is used for 16-bit gamma tables -- only the top level pointers are
960  * const; this could be changed:
961  */
962 typedef const png_uint_16p * png_const_uint_16pp;
963 
964 /* Added to libpng-1.5.7: sRGB conversion tables */
965 #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
966    defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
967 #ifdef PNG_SIMPLIFIED_READ_SUPPORTED
968 PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_table, [256]);
969    /* Convert from an sRGB encoded value 0..255 to a 16-bit linear value,
970     * 0..65535.  This table gives the closest 16-bit answers (no errors).
971     */
972 #endif
973 
974 PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_base, [512]);
975 PNG_INTERNAL_DATA(const png_byte, png_sRGB_delta, [512]);
976 
977 #define PNG_sRGB_FROM_LINEAR(linear) \
978   ((png_byte)(0xff & ((png_sRGB_base[(linear)>>15] \
979    + ((((linear) & 0x7fff)*png_sRGB_delta[(linear)>>15])>>12)) >> 8)))
980    /* Given a value 'linear' in the range 0..255*65535 calculate the 8-bit sRGB
981     * encoded value with maximum error 0.646365.  Note that the input is not a
982     * 16-bit value; it has been multiplied by 255! */
983 #endif /* SIMPLIFIED_READ/WRITE */
984 
985 
986 /* Inhibit C++ name-mangling for libpng functions but not for system calls. */
987 #ifdef __cplusplus
988 extern "C" {
989 #endif /* __cplusplus */
990 
991 /* Internal functions; these are not exported from a DLL however because they
992  * are used within several of the C source files they have to be C extern.
993  *
994  * All of these functions must be declared with PNG_INTERNAL_FUNCTION.
995  */
996 
997 /* Zlib support */
998 #define PNG_UNEXPECTED_ZLIB_RETURN (-7)
999 PNG_INTERNAL_FUNCTION(void, png_zstream_error,(png_structrp png_ptr, int ret),
1000    PNG_EMPTY);
1001    /* Used by the zlib handling functions to ensure that z_stream::msg is always
1002     * set before they return.
1003     */
1004 
1005 #ifdef PNG_WRITE_SUPPORTED
1006 PNG_INTERNAL_FUNCTION(void,png_free_buffer_list,(png_structrp png_ptr,
1007    png_compression_bufferp *list),PNG_EMPTY);
1008    /* Free the buffer list used by the compressed write code. */
1009 #endif
1010 
1011 #if defined(PNG_FLOATING_POINT_SUPPORTED) && \
1012    !defined(PNG_FIXED_POINT_MACRO_SUPPORTED) && \
1013    (defined(PNG_gAMA_SUPPORTED) || defined(PNG_cHRM_SUPPORTED) || \
1014    defined(PNG_sCAL_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) || \
1015    defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)) || \
1016    (defined(PNG_sCAL_SUPPORTED) && \
1017    defined(PNG_FLOATING_ARITHMETIC_SUPPORTED))
1018 PNG_INTERNAL_FUNCTION(png_fixed_point,png_fixed,(png_const_structrp png_ptr,
1019    double fp, png_const_charp text),PNG_EMPTY);
1020 #endif
1021 
1022 /* Check the user version string for compatibility, returns false if the version
1023  * numbers aren't compatible.
1024  */
1025 PNG_INTERNAL_FUNCTION(int,png_user_version_check,(png_structrp png_ptr,
1026    png_const_charp user_png_ver),PNG_EMPTY);
1027 
1028 /* Internal base allocator - no messages, NULL on failure to allocate.  This
1029  * does, however, call the application provided allocator and that could call
1030  * png_error (although that would be a bug in the application implementation.)
1031  */
1032 PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_base,(png_const_structrp png_ptr,
1033    png_alloc_size_t size),PNG_ALLOCATED);
1034 
1035 #if defined(PNG_TEXT_SUPPORTED) || defined(PNG_sPLT_SUPPORTED) ||\
1036    defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED)
1037 /* Internal array allocator, outputs no error or warning messages on failure,
1038  * just returns NULL.
1039  */
1040 PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_array,(png_const_structrp png_ptr,
1041    int nelements, size_t element_size),PNG_ALLOCATED);
1042 
1043 /* The same but an existing array is extended by add_elements.  This function
1044  * also memsets the new elements to 0 and copies the old elements.  The old
1045  * array is not freed or altered.
1046  */
1047 PNG_INTERNAL_FUNCTION(png_voidp,png_realloc_array,(png_const_structrp png_ptr,
1048    png_const_voidp array, int old_elements, int add_elements,
1049    size_t element_size),PNG_ALLOCATED);
1050 #endif /* text, sPLT or unknown chunks */
1051 
1052 /* Magic to create a struct when there is no struct to call the user supplied
1053  * memory allocators.  Because error handling has not been set up the memory
1054  * handlers can't safely call png_error, but this is an obscure and undocumented
1055  * restriction so libpng has to assume that the 'free' handler, at least, might
1056  * call png_error.
1057  */
1058 PNG_INTERNAL_FUNCTION(png_structp,png_create_png_struct,
1059    (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
1060     png_error_ptr warn_fn, png_voidp mem_ptr, png_malloc_ptr malloc_fn,
1061     png_free_ptr free_fn),PNG_ALLOCATED);
1062 
1063 /* Free memory from internal libpng struct */
1064 PNG_INTERNAL_FUNCTION(void,png_destroy_png_struct,(png_structrp png_ptr),
1065    PNG_EMPTY);
1066 
1067 /* Free an allocated jmp_buf (always succeeds) */
1068 PNG_INTERNAL_FUNCTION(void,png_free_jmpbuf,(png_structrp png_ptr),PNG_EMPTY);
1069 
1070 /* Function to allocate memory for zlib.  PNGAPI is disallowed. */
1071 PNG_INTERNAL_FUNCTION(voidpf,png_zalloc,(voidpf png_ptr, uInt items, uInt size),
1072    PNG_ALLOCATED);
1073 
1074 /* Function to free memory for zlib.  PNGAPI is disallowed. */
1075 PNG_INTERNAL_FUNCTION(void,png_zfree,(voidpf png_ptr, voidpf ptr),PNG_EMPTY);
1076 
1077 /* Next four functions are used internally as callbacks.  PNGCBAPI is required
1078  * but not PNG_EXPORT.  PNGAPI added at libpng version 1.2.3, changed to
1079  * PNGCBAPI at 1.5.0
1080  */
1081 
1082 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_read_data,(png_structp png_ptr,
1083     png_bytep data, size_t length),PNG_EMPTY);
1084 
1085 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1086 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_push_fill_buffer,(png_structp png_ptr,
1087     png_bytep buffer, size_t length),PNG_EMPTY);
1088 #endif
1089 
1090 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_write_data,(png_structp png_ptr,
1091     png_bytep data, size_t length),PNG_EMPTY);
1092 
1093 #ifdef PNG_WRITE_FLUSH_SUPPORTED
1094 #  ifdef PNG_STDIO_SUPPORTED
1095 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_flush,(png_structp png_ptr),
1096    PNG_EMPTY);
1097 #  endif
1098 #endif
1099 
1100 /* Reset the CRC variable */
1101 PNG_INTERNAL_FUNCTION(void,png_reset_crc,(png_structrp png_ptr),PNG_EMPTY);
1102 
1103 /* Write the "data" buffer to whatever output you are using */
1104 PNG_INTERNAL_FUNCTION(void,png_write_data,(png_structrp png_ptr,
1105     png_const_bytep data, size_t length),PNG_EMPTY);
1106 
1107 /* Read and check the PNG file signature */
1108 PNG_INTERNAL_FUNCTION(void,png_read_sig,(png_structrp png_ptr,
1109    png_inforp info_ptr),PNG_EMPTY);
1110 
1111 /* Read the chunk header (length + type name) */
1112 PNG_INTERNAL_FUNCTION(png_uint_32,png_read_chunk_header,(png_structrp png_ptr),
1113    PNG_EMPTY);
1114 
1115 /* Read data from whatever input you are using into the "data" buffer */
1116 PNG_INTERNAL_FUNCTION(void,png_read_data,(png_structrp png_ptr, png_bytep data,
1117     size_t length),PNG_EMPTY);
1118 
1119 /* Read bytes into buf, and update png_ptr->crc */
1120 PNG_INTERNAL_FUNCTION(void,png_crc_read,(png_structrp png_ptr, png_bytep buf,
1121     png_uint_32 length),PNG_EMPTY);
1122 
1123 /* Read "skip" bytes, read the file crc, and (optionally) verify png_ptr->crc */
1124 PNG_INTERNAL_FUNCTION(int,png_crc_finish,(png_structrp png_ptr,
1125    png_uint_32 skip),PNG_EMPTY);
1126 
1127 /* Read the CRC from the file and compare it to the libpng calculated CRC */
1128 PNG_INTERNAL_FUNCTION(int,png_crc_error,(png_structrp png_ptr),PNG_EMPTY);
1129 
1130 /* Calculate the CRC over a section of data.  Note that we are only
1131  * passing a maximum of 64K on systems that have this as a memory limit,
1132  * since this is the maximum buffer size we can specify.
1133  */
1134 PNG_INTERNAL_FUNCTION(void,png_calculate_crc,(png_structrp png_ptr,
1135    png_const_bytep ptr, size_t length),PNG_EMPTY);
1136 
1137 #ifdef PNG_WRITE_FLUSH_SUPPORTED
1138 PNG_INTERNAL_FUNCTION(void,png_flush,(png_structrp png_ptr),PNG_EMPTY);
1139 #endif
1140 
1141 /* Write various chunks */
1142 
1143 /* Write the IHDR chunk, and update the png_struct with the necessary
1144  * information.
1145  */
1146 PNG_INTERNAL_FUNCTION(void,png_write_IHDR,(png_structrp png_ptr,
1147    png_uint_32 width, png_uint_32 height, int bit_depth, int color_type,
1148    int compression_method, int filter_method, int interlace_method),PNG_EMPTY);
1149 
1150 PNG_INTERNAL_FUNCTION(void,png_write_PLTE,(png_structrp png_ptr,
1151    png_const_colorp palette, png_uint_32 num_pal),PNG_EMPTY);
1152 
1153 PNG_INTERNAL_FUNCTION(void,png_compress_IDAT,(png_structrp png_ptr,
1154    png_const_bytep row_data, png_alloc_size_t row_data_length, int flush),
1155    PNG_EMPTY);
1156 
1157 PNG_INTERNAL_FUNCTION(void,png_write_IEND,(png_structrp png_ptr),PNG_EMPTY);
1158 
1159 #ifdef PNG_WRITE_gAMA_SUPPORTED
1160 PNG_INTERNAL_FUNCTION(void,png_write_gAMA_fixed,(png_structrp png_ptr,
1161     png_fixed_point file_gamma),PNG_EMPTY);
1162 #endif
1163 
1164 #ifdef PNG_WRITE_sBIT_SUPPORTED
1165 PNG_INTERNAL_FUNCTION(void,png_write_sBIT,(png_structrp png_ptr,
1166     png_const_color_8p sbit, int color_type),PNG_EMPTY);
1167 #endif
1168 
1169 #ifdef PNG_WRITE_cHRM_SUPPORTED
1170 PNG_INTERNAL_FUNCTION(void,png_write_cHRM_fixed,(png_structrp png_ptr,
1171     const png_xy *xy), PNG_EMPTY);
1172    /* The xy value must have been previously validated */
1173 #endif
1174 
1175 #ifdef PNG_WRITE_sRGB_SUPPORTED
1176 PNG_INTERNAL_FUNCTION(void,png_write_sRGB,(png_structrp png_ptr,
1177     int intent),PNG_EMPTY);
1178 #endif
1179 
1180 #ifdef PNG_WRITE_eXIf_SUPPORTED
1181 PNG_INTERNAL_FUNCTION(void,png_write_eXIf,(png_structrp png_ptr,
1182     png_bytep exif, int num_exif),PNG_EMPTY);
1183 #endif
1184 
1185 #ifdef PNG_WRITE_iCCP_SUPPORTED
1186 PNG_INTERNAL_FUNCTION(void,png_write_iCCP,(png_structrp png_ptr,
1187    png_const_charp name, png_const_bytep profile), PNG_EMPTY);
1188    /* The profile must have been previously validated for correctness, the
1189     * length comes from the first four bytes.  Only the base, deflate,
1190     * compression is supported.
1191     */
1192 #endif
1193 
1194 #ifdef PNG_WRITE_sPLT_SUPPORTED
1195 PNG_INTERNAL_FUNCTION(void,png_write_sPLT,(png_structrp png_ptr,
1196     png_const_sPLT_tp palette),PNG_EMPTY);
1197 #endif
1198 
1199 #ifdef PNG_WRITE_tRNS_SUPPORTED
1200 PNG_INTERNAL_FUNCTION(void,png_write_tRNS,(png_structrp png_ptr,
1201     png_const_bytep trans, png_const_color_16p values, int number,
1202     int color_type),PNG_EMPTY);
1203 #endif
1204 
1205 #ifdef PNG_WRITE_bKGD_SUPPORTED
1206 PNG_INTERNAL_FUNCTION(void,png_write_bKGD,(png_structrp png_ptr,
1207     png_const_color_16p values, int color_type),PNG_EMPTY);
1208 #endif
1209 
1210 #ifdef PNG_WRITE_hIST_SUPPORTED
1211 PNG_INTERNAL_FUNCTION(void,png_write_hIST,(png_structrp png_ptr,
1212     png_const_uint_16p hist, int num_hist),PNG_EMPTY);
1213 #endif
1214 
1215 /* Chunks that have keywords */
1216 #ifdef PNG_WRITE_tEXt_SUPPORTED
1217 PNG_INTERNAL_FUNCTION(void,png_write_tEXt,(png_structrp png_ptr,
1218    png_const_charp key, png_const_charp text, size_t text_len),PNG_EMPTY);
1219 #endif
1220 
1221 #ifdef PNG_WRITE_zTXt_SUPPORTED
1222 PNG_INTERNAL_FUNCTION(void,png_write_zTXt,(png_structrp png_ptr, png_const_charp
1223     key, png_const_charp text, int compression),PNG_EMPTY);
1224 #endif
1225 
1226 #ifdef PNG_WRITE_iTXt_SUPPORTED
1227 PNG_INTERNAL_FUNCTION(void,png_write_iTXt,(png_structrp png_ptr,
1228     int compression, png_const_charp key, png_const_charp lang,
1229     png_const_charp lang_key, png_const_charp text),PNG_EMPTY);
1230 #endif
1231 
1232 #ifdef PNG_TEXT_SUPPORTED  /* Added at version 1.0.14 and 1.2.4 */
1233 PNG_INTERNAL_FUNCTION(int,png_set_text_2,(png_const_structrp png_ptr,
1234     png_inforp info_ptr, png_const_textp text_ptr, int num_text),PNG_EMPTY);
1235 #endif
1236 
1237 #ifdef PNG_WRITE_oFFs_SUPPORTED
1238 PNG_INTERNAL_FUNCTION(void,png_write_oFFs,(png_structrp png_ptr,
1239     png_int_32 x_offset, png_int_32 y_offset, int unit_type),PNG_EMPTY);
1240 #endif
1241 
1242 #ifdef PNG_WRITE_pCAL_SUPPORTED
1243 PNG_INTERNAL_FUNCTION(void,png_write_pCAL,(png_structrp png_ptr,
1244     png_charp purpose, png_int_32 X0, png_int_32 X1, int type, int nparams,
1245     png_const_charp units, png_charpp params),PNG_EMPTY);
1246 #endif
1247 
1248 #ifdef PNG_WRITE_pHYs_SUPPORTED
1249 PNG_INTERNAL_FUNCTION(void,png_write_pHYs,(png_structrp png_ptr,
1250     png_uint_32 x_pixels_per_unit, png_uint_32 y_pixels_per_unit,
1251     int unit_type),PNG_EMPTY);
1252 #endif
1253 
1254 #ifdef PNG_WRITE_tIME_SUPPORTED
1255 PNG_INTERNAL_FUNCTION(void,png_write_tIME,(png_structrp png_ptr,
1256     png_const_timep mod_time),PNG_EMPTY);
1257 #endif
1258 
1259 #ifdef PNG_WRITE_sCAL_SUPPORTED
1260 PNG_INTERNAL_FUNCTION(void,png_write_sCAL_s,(png_structrp png_ptr,
1261     int unit, png_const_charp width, png_const_charp height),PNG_EMPTY);
1262 #endif
1263 
1264 /* Called when finished processing a row of data */
1265 PNG_INTERNAL_FUNCTION(void,png_write_finish_row,(png_structrp png_ptr),
1266     PNG_EMPTY);
1267 
1268 /* Internal use only.   Called before first row of data */
1269 PNG_INTERNAL_FUNCTION(void,png_write_start_row,(png_structrp png_ptr),
1270     PNG_EMPTY);
1271 
1272 /* Combine a row of data, dealing with alpha, etc. if requested.  'row' is an
1273  * array of png_ptr->width pixels.  If the image is not interlaced or this
1274  * is the final pass this just does a memcpy, otherwise the "display" flag
1275  * is used to determine whether to copy pixels that are not in the current pass.
1276  *
1277  * Because 'png_do_read_interlace' (below) replicates pixels this allows this
1278  * function to achieve the documented 'blocky' appearance during interlaced read
1279  * if display is 1 and the 'sparkle' appearance, where existing pixels in 'row'
1280  * are not changed if they are not in the current pass, when display is 0.
1281  *
1282  * 'display' must be 0 or 1, otherwise the memcpy will be done regardless.
1283  *
1284  * The API always reads from the png_struct row buffer and always assumes that
1285  * it is full width (png_do_read_interlace has already been called.)
1286  *
1287  * This function is only ever used to write to row buffers provided by the
1288  * caller of the relevant libpng API and the row must have already been
1289  * transformed by the read transformations.
1290  *
1291  * The PNG_USE_COMPILE_TIME_MASKS option causes generation of pre-computed
1292  * bitmasks for use within the code, otherwise runtime generated masks are used.
1293  * The default is compile time masks.
1294  */
1295 #ifndef PNG_USE_COMPILE_TIME_MASKS
1296 #  define PNG_USE_COMPILE_TIME_MASKS 1
1297 #endif
1298 PNG_INTERNAL_FUNCTION(void,png_combine_row,(png_const_structrp png_ptr,
1299     png_bytep row, int display),PNG_EMPTY);
1300 
1301 #ifdef PNG_READ_INTERLACING_SUPPORTED
1302 /* Expand an interlaced row: the 'row_info' describes the pass data that has
1303  * been read in and must correspond to the pixels in 'row', the pixels are
1304  * expanded (moved apart) in 'row' to match the final layout, when doing this
1305  * the pixels are *replicated* to the intervening space.  This is essential for
1306  * the correct operation of png_combine_row, above.
1307  */
1308 PNG_INTERNAL_FUNCTION(void,png_do_read_interlace,(png_row_infop row_info,
1309     png_bytep row, int pass, png_uint_32 transformations),PNG_EMPTY);
1310 #endif
1311 
1312 /* GRR TO DO (2.0 or whenever):  simplify other internal calling interfaces */
1313 
1314 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1315 /* Grab pixels out of a row for an interlaced pass */
1316 PNG_INTERNAL_FUNCTION(void,png_do_write_interlace,(png_row_infop row_info,
1317     png_bytep row, int pass),PNG_EMPTY);
1318 #endif
1319 
1320 /* Unfilter a row: check the filter value before calling this, there is no point
1321  * calling it for PNG_FILTER_VALUE_NONE.
1322  */
1323 PNG_INTERNAL_FUNCTION(void,png_read_filter_row,(png_structrp pp, png_row_infop
1324     row_info, png_bytep row, png_const_bytep prev_row, int filter),PNG_EMPTY);
1325 
1326 #if PNG_ARM_NEON_OPT > 0
1327 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_up_neon,(png_row_infop row_info,
1328     png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1329 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_neon,(png_row_infop
1330     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1331 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_neon,(png_row_infop
1332     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1333 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_neon,(png_row_infop
1334     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1335 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_neon,(png_row_infop
1336     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1337 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_neon,(png_row_infop
1338     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1339 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_neon,(png_row_infop
1340     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1341 #endif
1342 
1343 #if PNG_MIPS_MSA_IMPLEMENTATION == 1
1344 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_up_msa,(png_row_infop row_info,
1345     png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1346 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_msa,(png_row_infop
1347     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1348 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_msa,(png_row_infop
1349     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1350 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_msa,(png_row_infop
1351     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1352 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_msa,(png_row_infop
1353     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1354 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_msa,(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_paeth4_msa,(png_row_infop
1357     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1358 #endif
1359 
1360 #if PNG_MIPS_MMI_IMPLEMENTATION > 0
1361 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_up_mmi,(png_row_infop row_info,
1362     png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1363 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_mmi,(png_row_infop
1364     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1365 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_mmi,(png_row_infop
1366     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1367 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_mmi,(png_row_infop
1368     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1369 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_mmi,(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_paeth3_mmi,(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_paeth4_mmi,(png_row_infop
1374     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1375 #endif
1376 
1377 #if PNG_POWERPC_VSX_OPT > 0
1378 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_up_vsx,(png_row_infop row_info,
1379     png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1380 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_vsx,(png_row_infop
1381     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1382 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_vsx,(png_row_infop
1383     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1384 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_vsx,(png_row_infop
1385     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1386 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_vsx,(png_row_infop
1387     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1388 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_vsx,(png_row_infop
1389     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1390 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_vsx,(png_row_infop
1391     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1392 #endif
1393 
1394 #if PNG_INTEL_SSE_IMPLEMENTATION > 0
1395 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_sse2,(png_row_infop
1396     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1397 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_sse2,(png_row_infop
1398     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1399 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_sse2,(png_row_infop
1400     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1401 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_sse2,(png_row_infop
1402     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1403 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_sse2,(png_row_infop
1404     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1405 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_sse2,(png_row_infop
1406     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1407 #endif
1408 
1409 #if PNG_LOONGARCH_LSX_IMPLEMENTATION == 1
1410 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_up_lsx,(png_row_infop
1411     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1412 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_lsx,(png_row_infop
1413     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1414 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_lsx,(png_row_infop
1415     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1416 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_lsx,(png_row_infop
1417     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1418 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_lsx,(png_row_infop
1419     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1420 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_lsx,(png_row_infop
1421     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1422 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_lsx,(png_row_infop
1423     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1424 #endif
1425 
1426 /* Choose the best filter to use and filter the row data */
1427 PNG_INTERNAL_FUNCTION(void,png_write_find_filter,(png_structrp png_ptr,
1428     png_row_infop row_info),PNG_EMPTY);
1429 
1430 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1431 PNG_INTERNAL_FUNCTION(void,png_read_IDAT_data,(png_structrp png_ptr,
1432    png_bytep output, png_alloc_size_t avail_out),PNG_EMPTY);
1433    /* Read 'avail_out' bytes of data from the IDAT stream.  If the output buffer
1434     * is NULL the function checks, instead, for the end of the stream.  In this
1435     * case a benign error will be issued if the stream end is not found or if
1436     * extra data has to be consumed.
1437     */
1438 PNG_INTERNAL_FUNCTION(void,png_read_finish_IDAT,(png_structrp png_ptr),
1439    PNG_EMPTY);
1440    /* This cleans up when the IDAT LZ stream does not end when the last image
1441     * byte is read; there is still some pending input.
1442     */
1443 
1444 PNG_INTERNAL_FUNCTION(void,png_read_finish_row,(png_structrp png_ptr),
1445    PNG_EMPTY);
1446    /* Finish a row while reading, dealing with interlacing passes, etc. */
1447 #endif /* SEQUENTIAL_READ */
1448 
1449 /* Initialize the row buffers, etc. */
1450 PNG_INTERNAL_FUNCTION(void,png_read_start_row,(png_structrp png_ptr),PNG_EMPTY);
1451 
1452 #if ZLIB_VERNUM >= 0x1240
1453 PNG_INTERNAL_FUNCTION(int,png_zlib_inflate,(png_structrp png_ptr, int flush),
1454       PNG_EMPTY);
1455 #  define PNG_INFLATE(pp, flush) png_zlib_inflate(pp, flush)
1456 #else /* Zlib < 1.2.4 */
1457 #  define PNG_INFLATE(pp, flush) inflate(&(pp)->zstream, flush)
1458 #endif /* Zlib < 1.2.4 */
1459 
1460 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1461 /* Optional call to update the users info structure */
1462 PNG_INTERNAL_FUNCTION(void,png_read_transform_info,(png_structrp png_ptr,
1463     png_inforp info_ptr),PNG_EMPTY);
1464 #endif
1465 
1466 /* Shared transform functions, defined in pngtran.c */
1467 #if defined(PNG_WRITE_FILLER_SUPPORTED) || \
1468     defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
1469 PNG_INTERNAL_FUNCTION(void,png_do_strip_channel,(png_row_infop row_info,
1470     png_bytep row, int at_start),PNG_EMPTY);
1471 #endif
1472 
1473 #ifdef PNG_16BIT_SUPPORTED
1474 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
1475 PNG_INTERNAL_FUNCTION(void,png_do_swap,(png_row_infop row_info,
1476     png_bytep row),PNG_EMPTY);
1477 #endif
1478 #endif
1479 
1480 #if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
1481     defined(PNG_WRITE_PACKSWAP_SUPPORTED)
1482 PNG_INTERNAL_FUNCTION(void,png_do_packswap,(png_row_infop row_info,
1483     png_bytep row),PNG_EMPTY);
1484 #endif
1485 
1486 #if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
1487 PNG_INTERNAL_FUNCTION(void,png_do_invert,(png_row_infop row_info,
1488     png_bytep row),PNG_EMPTY);
1489 #endif
1490 
1491 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
1492 PNG_INTERNAL_FUNCTION(void,png_do_bgr,(png_row_infop row_info,
1493     png_bytep row),PNG_EMPTY);
1494 #endif
1495 
1496 /* The following decodes the appropriate chunks, and does error correction,
1497  * then calls the appropriate callback for the chunk if it is valid.
1498  */
1499 
1500 /* Decode the IHDR chunk */
1501 PNG_INTERNAL_FUNCTION(void,png_handle_IHDR,(png_structrp png_ptr,
1502     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1503 PNG_INTERNAL_FUNCTION(void,png_handle_PLTE,(png_structrp png_ptr,
1504     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1505 PNG_INTERNAL_FUNCTION(void,png_handle_IEND,(png_structrp png_ptr,
1506     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1507 
1508 #ifdef PNG_READ_bKGD_SUPPORTED
1509 PNG_INTERNAL_FUNCTION(void,png_handle_bKGD,(png_structrp png_ptr,
1510     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1511 #endif
1512 
1513 #ifdef PNG_READ_cHRM_SUPPORTED
1514 PNG_INTERNAL_FUNCTION(void,png_handle_cHRM,(png_structrp png_ptr,
1515     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1516 #endif
1517 
1518 #ifdef PNG_READ_eXIf_SUPPORTED
1519 PNG_INTERNAL_FUNCTION(void,png_handle_eXIf,(png_structrp png_ptr,
1520     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1521 #endif
1522 
1523 #ifdef PNG_READ_gAMA_SUPPORTED
1524 PNG_INTERNAL_FUNCTION(void,png_handle_gAMA,(png_structrp png_ptr,
1525     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1526 #endif
1527 
1528 #ifdef PNG_READ_hIST_SUPPORTED
1529 PNG_INTERNAL_FUNCTION(void,png_handle_hIST,(png_structrp png_ptr,
1530     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1531 #endif
1532 
1533 #ifdef PNG_READ_iCCP_SUPPORTED
1534 PNG_INTERNAL_FUNCTION(void,png_handle_iCCP,(png_structrp png_ptr,
1535     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1536 #endif /* READ_iCCP */
1537 
1538 #ifdef PNG_READ_iTXt_SUPPORTED
1539 PNG_INTERNAL_FUNCTION(void,png_handle_iTXt,(png_structrp png_ptr,
1540     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1541 #endif
1542 
1543 #ifdef PNG_READ_oFFs_SUPPORTED
1544 PNG_INTERNAL_FUNCTION(void,png_handle_oFFs,(png_structrp png_ptr,
1545     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1546 #endif
1547 
1548 #ifdef PNG_READ_pCAL_SUPPORTED
1549 PNG_INTERNAL_FUNCTION(void,png_handle_pCAL,(png_structrp png_ptr,
1550     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1551 #endif
1552 
1553 #ifdef PNG_READ_pHYs_SUPPORTED
1554 PNG_INTERNAL_FUNCTION(void,png_handle_pHYs,(png_structrp png_ptr,
1555     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1556 #endif
1557 
1558 #ifdef PNG_READ_sBIT_SUPPORTED
1559 PNG_INTERNAL_FUNCTION(void,png_handle_sBIT,(png_structrp png_ptr,
1560     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1561 #endif
1562 
1563 #ifdef PNG_READ_sCAL_SUPPORTED
1564 PNG_INTERNAL_FUNCTION(void,png_handle_sCAL,(png_structrp png_ptr,
1565     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1566 #endif
1567 
1568 #ifdef PNG_READ_sPLT_SUPPORTED
1569 PNG_INTERNAL_FUNCTION(void,png_handle_sPLT,(png_structrp png_ptr,
1570     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1571 #endif /* READ_sPLT */
1572 
1573 #ifdef PNG_READ_sRGB_SUPPORTED
1574 PNG_INTERNAL_FUNCTION(void,png_handle_sRGB,(png_structrp png_ptr,
1575     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1576 #endif
1577 
1578 #ifdef PNG_READ_tEXt_SUPPORTED
1579 PNG_INTERNAL_FUNCTION(void,png_handle_tEXt,(png_structrp png_ptr,
1580     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1581 #endif
1582 
1583 #ifdef PNG_READ_tIME_SUPPORTED
1584 PNG_INTERNAL_FUNCTION(void,png_handle_tIME,(png_structrp png_ptr,
1585     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1586 #endif
1587 
1588 #ifdef PNG_READ_tRNS_SUPPORTED
1589 PNG_INTERNAL_FUNCTION(void,png_handle_tRNS,(png_structrp png_ptr,
1590     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1591 #endif
1592 
1593 #ifdef PNG_READ_zTXt_SUPPORTED
1594 PNG_INTERNAL_FUNCTION(void,png_handle_zTXt,(png_structrp png_ptr,
1595     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1596 #endif
1597 
1598 PNG_INTERNAL_FUNCTION(void,png_check_chunk_name,(png_const_structrp png_ptr,
1599     png_uint_32 chunk_name),PNG_EMPTY);
1600 
1601 PNG_INTERNAL_FUNCTION(void,png_check_chunk_length,(png_const_structrp png_ptr,
1602     png_uint_32 chunk_length),PNG_EMPTY);
1603 
1604 PNG_INTERNAL_FUNCTION(void,png_handle_unknown,(png_structrp png_ptr,
1605     png_inforp info_ptr, png_uint_32 length, int keep),PNG_EMPTY);
1606    /* This is the function that gets called for unknown chunks.  The 'keep'
1607     * argument is either non-zero for a known chunk that has been set to be
1608     * handled as unknown or zero for an unknown chunk.  By default the function
1609     * just skips the chunk or errors out if it is critical.
1610     */
1611 
1612 #if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) ||\
1613     defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
1614 PNG_INTERNAL_FUNCTION(int,png_chunk_unknown_handling,
1615     (png_const_structrp png_ptr, png_uint_32 chunk_name),PNG_EMPTY);
1616    /* Exactly as the API png_handle_as_unknown() except that the argument is a
1617     * 32-bit chunk name, not a string.
1618     */
1619 #endif /* READ_UNKNOWN_CHUNKS || HANDLE_AS_UNKNOWN */
1620 
1621 /* Handle the transformations for reading and writing */
1622 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1623 PNG_INTERNAL_FUNCTION(void,png_do_read_transformations,(png_structrp png_ptr,
1624    png_row_infop row_info),PNG_EMPTY);
1625 #endif
1626 #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
1627 PNG_INTERNAL_FUNCTION(void,png_do_write_transformations,(png_structrp png_ptr,
1628    png_row_infop row_info),PNG_EMPTY);
1629 #endif
1630 
1631 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1632 PNG_INTERNAL_FUNCTION(void,png_init_read_transformations,(png_structrp png_ptr),
1633     PNG_EMPTY);
1634 #endif
1635 
1636 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1637 PNG_INTERNAL_FUNCTION(void,png_push_read_chunk,(png_structrp png_ptr,
1638     png_inforp info_ptr),PNG_EMPTY);
1639 PNG_INTERNAL_FUNCTION(void,png_push_read_sig,(png_structrp png_ptr,
1640     png_inforp info_ptr),PNG_EMPTY);
1641 PNG_INTERNAL_FUNCTION(void,png_push_check_crc,(png_structrp png_ptr),PNG_EMPTY);
1642 PNG_INTERNAL_FUNCTION(void,png_push_save_buffer,(png_structrp png_ptr),
1643     PNG_EMPTY);
1644 PNG_INTERNAL_FUNCTION(void,png_push_restore_buffer,(png_structrp png_ptr,
1645     png_bytep buffer, size_t buffer_length),PNG_EMPTY);
1646 PNG_INTERNAL_FUNCTION(void,png_push_read_IDAT,(png_structrp png_ptr),PNG_EMPTY);
1647 PNG_INTERNAL_FUNCTION(void,png_process_IDAT_data,(png_structrp png_ptr,
1648     png_bytep buffer, size_t buffer_length),PNG_EMPTY);
1649 PNG_INTERNAL_FUNCTION(void,png_push_process_row,(png_structrp png_ptr),
1650     PNG_EMPTY);
1651 PNG_INTERNAL_FUNCTION(void,png_push_handle_unknown,(png_structrp png_ptr,
1652    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1653 PNG_INTERNAL_FUNCTION(void,png_push_have_info,(png_structrp png_ptr,
1654    png_inforp info_ptr),PNG_EMPTY);
1655 PNG_INTERNAL_FUNCTION(void,png_push_have_end,(png_structrp png_ptr,
1656    png_inforp info_ptr),PNG_EMPTY);
1657 PNG_INTERNAL_FUNCTION(void,png_push_have_row,(png_structrp png_ptr,
1658     png_bytep row),PNG_EMPTY);
1659 PNG_INTERNAL_FUNCTION(void,png_push_read_end,(png_structrp png_ptr,
1660     png_inforp info_ptr),PNG_EMPTY);
1661 PNG_INTERNAL_FUNCTION(void,png_process_some_data,(png_structrp png_ptr,
1662     png_inforp info_ptr),PNG_EMPTY);
1663 PNG_INTERNAL_FUNCTION(void,png_read_push_finish_row,(png_structrp png_ptr),
1664     PNG_EMPTY);
1665 #  ifdef PNG_READ_tEXt_SUPPORTED
1666 PNG_INTERNAL_FUNCTION(void,png_push_handle_tEXt,(png_structrp png_ptr,
1667     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1668 PNG_INTERNAL_FUNCTION(void,png_push_read_tEXt,(png_structrp png_ptr,
1669     png_inforp info_ptr),PNG_EMPTY);
1670 #  endif
1671 #  ifdef PNG_READ_zTXt_SUPPORTED
1672 PNG_INTERNAL_FUNCTION(void,png_push_handle_zTXt,(png_structrp png_ptr,
1673     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1674 PNG_INTERNAL_FUNCTION(void,png_push_read_zTXt,(png_structrp png_ptr,
1675     png_inforp info_ptr),PNG_EMPTY);
1676 #  endif
1677 #  ifdef PNG_READ_iTXt_SUPPORTED
1678 PNG_INTERNAL_FUNCTION(void,png_push_handle_iTXt,(png_structrp png_ptr,
1679     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1680 PNG_INTERNAL_FUNCTION(void,png_push_read_iTXt,(png_structrp png_ptr,
1681     png_inforp info_ptr),PNG_EMPTY);
1682 #  endif
1683 
1684 #endif /* PROGRESSIVE_READ */
1685 
1686 /* Added at libpng version 1.6.0 */
1687 #ifdef PNG_GAMMA_SUPPORTED
1688 PNG_INTERNAL_FUNCTION(void,png_colorspace_set_gamma,(png_const_structrp png_ptr,
1689     png_colorspacerp colorspace, png_fixed_point gAMA), PNG_EMPTY);
1690    /* Set the colorspace gamma with a value provided by the application or by
1691     * the gAMA chunk on read.  The value will override anything set by an ICC
1692     * profile.
1693     */
1694 
1695 PNG_INTERNAL_FUNCTION(void,png_colorspace_sync_info,(png_const_structrp png_ptr,
1696     png_inforp info_ptr), PNG_EMPTY);
1697    /* Synchronize the info 'valid' flags with the colorspace */
1698 
1699 PNG_INTERNAL_FUNCTION(void,png_colorspace_sync,(png_const_structrp png_ptr,
1700     png_inforp info_ptr), PNG_EMPTY);
1701    /* Copy the png_struct colorspace to the info_struct and call the above to
1702     * synchronize the flags.  Checks for NULL info_ptr and does nothing.
1703     */
1704 #endif
1705 
1706 /* Added at libpng version 1.4.0 */
1707 #ifdef PNG_COLORSPACE_SUPPORTED
1708 /* These internal functions are for maintaining the colorspace structure within
1709  * a png_info or png_struct (or, indeed, both).
1710  */
1711 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_chromaticities,
1712    (png_const_structrp png_ptr, png_colorspacerp colorspace, const png_xy *xy,
1713     int preferred), PNG_EMPTY);
1714 
1715 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_endpoints,
1716    (png_const_structrp png_ptr, png_colorspacerp colorspace, const png_XYZ *XYZ,
1717     int preferred), PNG_EMPTY);
1718 
1719 #ifdef PNG_sRGB_SUPPORTED
1720 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_sRGB,(png_const_structrp png_ptr,
1721    png_colorspacerp colorspace, int intent), PNG_EMPTY);
1722    /* This does set the colorspace gAMA and cHRM values too, but doesn't set the
1723     * flags to write them, if it returns false there was a problem and an error
1724     * message has already been output (but the colorspace may still need to be
1725     * synced to record the invalid flag).
1726     */
1727 #endif /* sRGB */
1728 
1729 #ifdef PNG_iCCP_SUPPORTED
1730 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_ICC,(png_const_structrp png_ptr,
1731    png_colorspacerp colorspace, png_const_charp name,
1732    png_uint_32 profile_length, png_const_bytep profile, int color_type),
1733    PNG_EMPTY);
1734    /* The 'name' is used for information only */
1735 
1736 /* Routines for checking parts of an ICC profile. */
1737 #ifdef PNG_READ_iCCP_SUPPORTED
1738 PNG_INTERNAL_FUNCTION(int,png_icc_check_length,(png_const_structrp png_ptr,
1739    png_colorspacerp colorspace, png_const_charp name,
1740    png_uint_32 profile_length), PNG_EMPTY);
1741 #endif /* READ_iCCP */
1742 PNG_INTERNAL_FUNCTION(int,png_icc_check_header,(png_const_structrp png_ptr,
1743    png_colorspacerp colorspace, png_const_charp name,
1744    png_uint_32 profile_length,
1745    png_const_bytep profile /* first 132 bytes only */, int color_type),
1746    PNG_EMPTY);
1747 PNG_INTERNAL_FUNCTION(int,png_icc_check_tag_table,(png_const_structrp png_ptr,
1748    png_colorspacerp colorspace, png_const_charp name,
1749    png_uint_32 profile_length,
1750    png_const_bytep profile /* header plus whole tag table */), PNG_EMPTY);
1751 #ifdef PNG_sRGB_SUPPORTED
1752 PNG_INTERNAL_FUNCTION(void,png_icc_set_sRGB,(
1753    png_const_structrp png_ptr, png_colorspacerp colorspace,
1754    png_const_bytep profile, uLong adler), PNG_EMPTY);
1755    /* 'adler' is the Adler32 checksum of the uncompressed profile data. It may
1756     * be zero to indicate that it is not available.  It is used, if provided,
1757     * as a fast check on the profile when checking to see if it is sRGB.
1758     */
1759 #endif
1760 #endif /* iCCP */
1761 
1762 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1763 PNG_INTERNAL_FUNCTION(void,png_colorspace_set_rgb_coefficients,
1764    (png_structrp png_ptr), PNG_EMPTY);
1765    /* Set the rgb_to_gray coefficients from the colorspace Y values */
1766 #endif /* READ_RGB_TO_GRAY */
1767 #endif /* COLORSPACE */
1768 
1769 /* Added at libpng version 1.4.0 */
1770 PNG_INTERNAL_FUNCTION(void,png_check_IHDR,(png_const_structrp png_ptr,
1771     png_uint_32 width, png_uint_32 height, int bit_depth,
1772     int color_type, int interlace_type, int compression_type,
1773     int filter_type),PNG_EMPTY);
1774 
1775 /* Added at libpng version 1.5.10 */
1776 #if defined(PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED) || \
1777     defined(PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED)
1778 PNG_INTERNAL_FUNCTION(void,png_do_check_palette_indexes,
1779    (png_structrp png_ptr, png_row_infop row_info),PNG_EMPTY);
1780 #endif
1781 
1782 #if defined(PNG_FLOATING_POINT_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED)
1783 PNG_INTERNAL_FUNCTION(void,png_fixed_error,(png_const_structrp png_ptr,
1784    png_const_charp name),PNG_NORETURN);
1785 #endif
1786 
1787 /* Puts 'string' into 'buffer' at buffer[pos], taking care never to overwrite
1788  * the end.  Always leaves the buffer nul terminated.  Never errors out (and
1789  * there is no error code.)
1790  */
1791 PNG_INTERNAL_FUNCTION(size_t,png_safecat,(png_charp buffer, size_t bufsize,
1792    size_t pos, png_const_charp string),PNG_EMPTY);
1793 
1794 /* Various internal functions to handle formatted warning messages, currently
1795  * only implemented for warnings.
1796  */
1797 #if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_TIME_RFC1123_SUPPORTED)
1798 /* Utility to dump an unsigned value into a buffer, given a start pointer and
1799  * and end pointer (which should point just *beyond* the end of the buffer!)
1800  * Returns the pointer to the start of the formatted string.  This utility only
1801  * does unsigned values.
1802  */
1803 PNG_INTERNAL_FUNCTION(png_charp,png_format_number,(png_const_charp start,
1804    png_charp end, int format, png_alloc_size_t number),PNG_EMPTY);
1805 
1806 /* Convenience macro that takes an array: */
1807 #define PNG_FORMAT_NUMBER(buffer,format,number) \
1808    png_format_number(buffer, buffer + (sizeof buffer), format, number)
1809 
1810 /* Suggested size for a number buffer (enough for 64 bits and a sign!) */
1811 #define PNG_NUMBER_BUFFER_SIZE 24
1812 
1813 /* These are the integer formats currently supported, the name is formed from
1814  * the standard printf(3) format string.
1815  */
1816 #define PNG_NUMBER_FORMAT_u     1 /* chose unsigned API! */
1817 #define PNG_NUMBER_FORMAT_02u   2
1818 #define PNG_NUMBER_FORMAT_d     1 /* chose signed API! */
1819 #define PNG_NUMBER_FORMAT_02d   2
1820 #define PNG_NUMBER_FORMAT_x     3
1821 #define PNG_NUMBER_FORMAT_02x   4
1822 #define PNG_NUMBER_FORMAT_fixed 5 /* choose the signed API */
1823 #endif
1824 
1825 #ifdef PNG_WARNINGS_SUPPORTED
1826 /* New defines and members adding in libpng-1.5.4 */
1827 #  define PNG_WARNING_PARAMETER_SIZE 32
1828 #  define PNG_WARNING_PARAMETER_COUNT 8 /* Maximum 9; see pngerror.c */
1829 
1830 /* An l-value of this type has to be passed to the APIs below to cache the
1831  * values of the parameters to a formatted warning message.
1832  */
1833 typedef char png_warning_parameters[PNG_WARNING_PARAMETER_COUNT][
1834    PNG_WARNING_PARAMETER_SIZE];
1835 
1836 PNG_INTERNAL_FUNCTION(void,png_warning_parameter,(png_warning_parameters p,
1837    int number, png_const_charp string),PNG_EMPTY);
1838    /* Parameters are limited in size to PNG_WARNING_PARAMETER_SIZE characters,
1839     * including the trailing '\0'.
1840     */
1841 PNG_INTERNAL_FUNCTION(void,png_warning_parameter_unsigned,
1842    (png_warning_parameters p, int number, int format, png_alloc_size_t value),
1843    PNG_EMPTY);
1844    /* Use png_alloc_size_t because it is an unsigned type as big as any we
1845     * need to output.  Use the following for a signed value.
1846     */
1847 PNG_INTERNAL_FUNCTION(void,png_warning_parameter_signed,
1848    (png_warning_parameters p, int number, int format, png_int_32 value),
1849    PNG_EMPTY);
1850 
1851 PNG_INTERNAL_FUNCTION(void,png_formatted_warning,(png_const_structrp png_ptr,
1852    png_warning_parameters p, png_const_charp message),PNG_EMPTY);
1853    /* 'message' follows the X/Open approach of using @1, @2 to insert
1854     * parameters previously supplied using the above functions.  Errors in
1855     * specifying the parameters will simply result in garbage substitutions.
1856     */
1857 #endif
1858 
1859 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
1860 /* Application errors (new in 1.6); use these functions (declared below) for
1861  * errors in the parameters or order of API function calls on read.  The
1862  * 'warning' should be used for an error that can be handled completely; the
1863  * 'error' for one which can be handled safely but which may lose application
1864  * information or settings.
1865  *
1866  * By default these both result in a png_error call prior to release, while in a
1867  * released version the 'warning' is just a warning.  However if the application
1868  * explicitly disables benign errors (explicitly permitting the code to lose
1869  * information) they both turn into warnings.
1870  *
1871  * If benign errors aren't supported they end up as the corresponding base call
1872  * (png_warning or png_error.)
1873  */
1874 PNG_INTERNAL_FUNCTION(void,png_app_warning,(png_const_structrp png_ptr,
1875    png_const_charp message),PNG_EMPTY);
1876    /* The application provided invalid parameters to an API function or called
1877     * an API function at the wrong time, libpng can completely recover.
1878     */
1879 
1880 PNG_INTERNAL_FUNCTION(void,png_app_error,(png_const_structrp png_ptr,
1881    png_const_charp message),PNG_EMPTY);
1882    /* As above but libpng will ignore the call, or attempt some other partial
1883     * recovery from the error.
1884     */
1885 #else
1886 #  define png_app_warning(pp,s) png_warning(pp,s)
1887 #  define png_app_error(pp,s) png_error(pp,s)
1888 #endif
1889 
1890 PNG_INTERNAL_FUNCTION(void,png_chunk_report,(png_const_structrp png_ptr,
1891    png_const_charp message, int error),PNG_EMPTY);
1892    /* Report a recoverable issue in chunk data.  On read this is used to report
1893     * a problem found while reading a particular chunk and the
1894     * png_chunk_benign_error or png_chunk_warning function is used as
1895     * appropriate.  On write this is used to report an error that comes from
1896     * data set via an application call to a png_set_ API and png_app_error or
1897     * png_app_warning is used as appropriate.
1898     *
1899     * The 'error' parameter must have one of the following values:
1900     */
1901 #define PNG_CHUNK_WARNING     0 /* never an error */
1902 #define PNG_CHUNK_WRITE_ERROR 1 /* an error only on write */
1903 #define PNG_CHUNK_ERROR       2 /* always an error */
1904 
1905 /* ASCII to FP interfaces, currently only implemented if sCAL
1906  * support is required.
1907  */
1908 #if defined(PNG_sCAL_SUPPORTED)
1909 /* MAX_DIGITS is actually the maximum number of characters in an sCAL
1910  * width or height, derived from the precision (number of significant
1911  * digits - a build time settable option) and assumptions about the
1912  * maximum ridiculous exponent.
1913  */
1914 #define PNG_sCAL_MAX_DIGITS (PNG_sCAL_PRECISION+1/*.*/+1/*E*/+10/*exponent*/)
1915 
1916 #ifdef PNG_FLOATING_POINT_SUPPORTED
1917 PNG_INTERNAL_FUNCTION(void,png_ascii_from_fp,(png_const_structrp png_ptr,
1918    png_charp ascii, size_t size, double fp, unsigned int precision),
1919    PNG_EMPTY);
1920 #endif /* FLOATING_POINT */
1921 
1922 #ifdef PNG_FIXED_POINT_SUPPORTED
1923 PNG_INTERNAL_FUNCTION(void,png_ascii_from_fixed,(png_const_structrp png_ptr,
1924    png_charp ascii, size_t size, png_fixed_point fp),PNG_EMPTY);
1925 #endif /* FIXED_POINT */
1926 #endif /* sCAL */
1927 
1928 #if defined(PNG_sCAL_SUPPORTED) || defined(PNG_pCAL_SUPPORTED)
1929 /* An internal API to validate the format of a floating point number.
1930  * The result is the index of the next character.  If the number is
1931  * not valid it will be the index of a character in the supposed number.
1932  *
1933  * The format of a number is defined in the PNG extensions specification
1934  * and this API is strictly conformant to that spec, not anyone elses!
1935  *
1936  * The format as a regular expression is:
1937  *
1938  * [+-]?[0-9]+.?([Ee][+-]?[0-9]+)?
1939  *
1940  * or:
1941  *
1942  * [+-]?.[0-9]+(.[0-9]+)?([Ee][+-]?[0-9]+)?
1943  *
1944  * The complexity is that either integer or fraction must be present and the
1945  * fraction is permitted to have no digits only if the integer is present.
1946  *
1947  * NOTE: The dangling E problem.
1948  *   There is a PNG valid floating point number in the following:
1949  *
1950  *       PNG floating point numbers are not greedy.
1951  *
1952  *   Working this out requires *TWO* character lookahead (because of the
1953  *   sign), the parser does not do this - it will fail at the 'r' - this
1954  *   doesn't matter for PNG sCAL chunk values, but it requires more care
1955  *   if the value were ever to be embedded in something more complex.  Use
1956  *   ANSI-C strtod if you need the lookahead.
1957  */
1958 /* State table for the parser. */
1959 #define PNG_FP_INTEGER    0  /* before or in integer */
1960 #define PNG_FP_FRACTION   1  /* before or in fraction */
1961 #define PNG_FP_EXPONENT   2  /* before or in exponent */
1962 #define PNG_FP_STATE      3  /* mask for the above */
1963 #define PNG_FP_SAW_SIGN   4  /* Saw +/- in current state */
1964 #define PNG_FP_SAW_DIGIT  8  /* Saw a digit in current state */
1965 #define PNG_FP_SAW_DOT   16  /* Saw a dot in current state */
1966 #define PNG_FP_SAW_E     32  /* Saw an E (or e) in current state */
1967 #define PNG_FP_SAW_ANY   60  /* Saw any of the above 4 */
1968 
1969 /* These three values don't affect the parser.  They are set but not used.
1970  */
1971 #define PNG_FP_WAS_VALID 64  /* Preceding substring is a valid fp number */
1972 #define PNG_FP_NEGATIVE 128  /* A negative number, including "-0" */
1973 #define PNG_FP_NONZERO  256  /* A non-zero value */
1974 #define PNG_FP_STICKY   448  /* The above three flags */
1975 
1976 /* This is available for the caller to store in 'state' if required.  Do not
1977  * call the parser after setting it (the parser sometimes clears it.)
1978  */
1979 #define PNG_FP_INVALID  512  /* Available for callers as a distinct value */
1980 
1981 /* Result codes for the parser (boolean - true means ok, false means
1982  * not ok yet.)
1983  */
1984 #define PNG_FP_MAYBE      0  /* The number may be valid in the future */
1985 #define PNG_FP_OK         1  /* The number is valid */
1986 
1987 /* Tests on the sticky non-zero and negative flags.  To pass these checks
1988  * the state must also indicate that the whole number is valid - this is
1989  * achieved by testing PNG_FP_SAW_DIGIT (see the implementation for why this
1990  * is equivalent to PNG_FP_OK above.)
1991  */
1992 #define PNG_FP_NZ_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NEGATIVE | PNG_FP_NONZERO)
1993    /* NZ_MASK: the string is valid and a non-zero negative value */
1994 #define PNG_FP_Z_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NONZERO)
1995    /* Z MASK: the string is valid and a non-zero value. */
1996    /* PNG_FP_SAW_DIGIT: the string is valid. */
1997 #define PNG_FP_IS_ZERO(state) (((state) & PNG_FP_Z_MASK) == PNG_FP_SAW_DIGIT)
1998 #define PNG_FP_IS_POSITIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_Z_MASK)
1999 #define PNG_FP_IS_NEGATIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_NZ_MASK)
2000 
2001 /* The actual parser.  This can be called repeatedly. It updates
2002  * the index into the string and the state variable (which must
2003  * be initialized to 0).  It returns a result code, as above.  There
2004  * is no point calling the parser any more if it fails to advance to
2005  * the end of the string - it is stuck on an invalid character (or
2006  * terminated by '\0').
2007  *
2008  * Note that the pointer will consume an E or even an E+ and then leave
2009  * a 'maybe' state even though a preceding integer.fraction is valid.
2010  * The PNG_FP_WAS_VALID flag indicates that a preceding substring was
2011  * a valid number.  It's possible to recover from this by calling
2012  * the parser again (from the start, with state 0) but with a string
2013  * that omits the last character (i.e. set the size to the index of
2014  * the problem character.)  This has not been tested within libpng.
2015  */
2016 PNG_INTERNAL_FUNCTION(int,png_check_fp_number,(png_const_charp string,
2017    size_t size, int *statep, size_t *whereami),PNG_EMPTY);
2018 
2019 /* This is the same but it checks a complete string and returns true
2020  * only if it just contains a floating point number.  As of 1.5.4 this
2021  * function also returns the state at the end of parsing the number if
2022  * it was valid (otherwise it returns 0.)  This can be used for testing
2023  * for negative or zero values using the sticky flag.
2024  */
2025 PNG_INTERNAL_FUNCTION(int,png_check_fp_string,(png_const_charp string,
2026    size_t size),PNG_EMPTY);
2027 #endif /* pCAL || sCAL */
2028 
2029 #if defined(PNG_GAMMA_SUPPORTED) ||\
2030     defined(PNG_INCH_CONVERSIONS_SUPPORTED) || defined(PNG_READ_pHYs_SUPPORTED)
2031 /* Added at libpng version 1.5.0 */
2032 /* This is a utility to provide a*times/div (rounded) and indicate
2033  * if there is an overflow.  The result is a boolean - false (0)
2034  * for overflow, true (1) if no overflow, in which case *res
2035  * holds the result.
2036  */
2037 PNG_INTERNAL_FUNCTION(int,png_muldiv,(png_fixed_point_p res, png_fixed_point a,
2038    png_int_32 multiplied_by, png_int_32 divided_by),PNG_EMPTY);
2039 #endif
2040 
2041 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_INCH_CONVERSIONS_SUPPORTED)
2042 /* Same deal, but issue a warning on overflow and return 0. */
2043 PNG_INTERNAL_FUNCTION(png_fixed_point,png_muldiv_warn,
2044    (png_const_structrp png_ptr, png_fixed_point a, png_int_32 multiplied_by,
2045    png_int_32 divided_by),PNG_EMPTY);
2046 #endif
2047 
2048 #ifdef PNG_GAMMA_SUPPORTED
2049 /* Calculate a reciprocal - used for gamma values.  This returns
2050  * 0 if the argument is 0 in order to maintain an undefined value;
2051  * there are no warnings.
2052  */
2053 PNG_INTERNAL_FUNCTION(png_fixed_point,png_reciprocal,(png_fixed_point a),
2054    PNG_EMPTY);
2055 
2056 #ifdef PNG_READ_GAMMA_SUPPORTED
2057 /* The same but gives a reciprocal of the product of two fixed point
2058  * values.  Accuracy is suitable for gamma calculations but this is
2059  * not exact - use png_muldiv for that.  Only required at present on read.
2060  */
2061 PNG_INTERNAL_FUNCTION(png_fixed_point,png_reciprocal2,(png_fixed_point a,
2062    png_fixed_point b),PNG_EMPTY);
2063 #endif
2064 
2065 /* Return true if the gamma value is significantly different from 1.0 */
2066 PNG_INTERNAL_FUNCTION(int,png_gamma_significant,(png_fixed_point gamma_value),
2067    PNG_EMPTY);
2068 #endif
2069 
2070 #ifdef PNG_READ_GAMMA_SUPPORTED
2071 /* Internal fixed point gamma correction.  These APIs are called as
2072  * required to convert single values - they don't need to be fast,
2073  * they are not used when processing image pixel values.
2074  *
2075  * While the input is an 'unsigned' value it must actually be the
2076  * correct bit value - 0..255 or 0..65535 as required.
2077  */
2078 PNG_INTERNAL_FUNCTION(png_uint_16,png_gamma_correct,(png_structrp png_ptr,
2079    unsigned int value, png_fixed_point gamma_value),PNG_EMPTY);
2080 PNG_INTERNAL_FUNCTION(png_uint_16,png_gamma_16bit_correct,(unsigned int value,
2081    png_fixed_point gamma_value),PNG_EMPTY);
2082 PNG_INTERNAL_FUNCTION(png_byte,png_gamma_8bit_correct,(unsigned int value,
2083    png_fixed_point gamma_value),PNG_EMPTY);
2084 PNG_INTERNAL_FUNCTION(void,png_destroy_gamma_table,(png_structrp png_ptr),
2085    PNG_EMPTY);
2086 PNG_INTERNAL_FUNCTION(void,png_build_gamma_table,(png_structrp png_ptr,
2087    int bit_depth),PNG_EMPTY);
2088 #endif
2089 
2090 /* SIMPLIFIED READ/WRITE SUPPORT */
2091 #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
2092    defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
2093 /* The internal structure that png_image::opaque points to. */
2094 typedef struct png_control
2095 {
2096    png_structp png_ptr;
2097    png_infop   info_ptr;
2098    png_voidp   error_buf;           /* Always a jmp_buf at present. */
2099 
2100    png_const_bytep memory;          /* Memory buffer. */
2101    size_t          size;            /* Size of the memory buffer. */
2102 
2103    unsigned int for_write       :1; /* Otherwise it is a read structure */
2104    unsigned int owned_file      :1; /* We own the file in io_ptr */
2105 } png_control;
2106 
2107 /* Return the pointer to the jmp_buf from a png_control: necessary because C
2108  * does not reveal the type of the elements of jmp_buf.
2109  */
2110 #ifdef __cplusplus
2111 #  define png_control_jmp_buf(pc) (((jmp_buf*)((pc)->error_buf))[0])
2112 #else
2113 #  define png_control_jmp_buf(pc) ((pc)->error_buf)
2114 #endif
2115 
2116 /* Utility to safely execute a piece of libpng code catching and logging any
2117  * errors that might occur.  Returns true on success, false on failure (either
2118  * of the function or as a result of a png_error.)
2119  */
2120 PNG_INTERNAL_CALLBACK(void,png_safe_error,(png_structp png_ptr,
2121    png_const_charp error_message),PNG_NORETURN);
2122 
2123 #ifdef PNG_WARNINGS_SUPPORTED
2124 PNG_INTERNAL_CALLBACK(void,png_safe_warning,(png_structp png_ptr,
2125    png_const_charp warning_message),PNG_EMPTY);
2126 #else
2127 #  define png_safe_warning 0/*dummy argument*/
2128 #endif
2129 
2130 PNG_INTERNAL_FUNCTION(int,png_safe_execute,(png_imagep image,
2131    int (*function)(png_voidp), png_voidp arg),PNG_EMPTY);
2132 
2133 /* Utility to log an error; this also cleans up the png_image; the function
2134  * always returns 0 (false).
2135  */
2136 PNG_INTERNAL_FUNCTION(int,png_image_error,(png_imagep image,
2137    png_const_charp error_message),PNG_EMPTY);
2138 
2139 #ifndef PNG_SIMPLIFIED_READ_SUPPORTED
2140 /* png_image_free is used by the write code but not exported */
2141 PNG_INTERNAL_FUNCTION(void, png_image_free, (png_imagep image), PNG_EMPTY);
2142 #endif /* !SIMPLIFIED_READ */
2143 
2144 #endif /* SIMPLIFIED READ/WRITE */
2145 
2146 /* These are initialization functions for hardware specific PNG filter
2147  * optimizations; list these here then select the appropriate one at compile
2148  * time using the macro PNG_FILTER_OPTIMIZATIONS.  If the macro is not defined
2149  * the generic code is used.
2150  */
2151 #ifdef PNG_FILTER_OPTIMIZATIONS
2152 PNG_INTERNAL_FUNCTION(void, PNG_FILTER_OPTIMIZATIONS, (png_structp png_ptr,
2153    unsigned int bpp), PNG_EMPTY);
2154    /* Just declare the optimization that will be used */
2155 #else
2156    /* List *all* the possible optimizations here - this branch is required if
2157     * the builder of libpng passes the definition of PNG_FILTER_OPTIMIZATIONS in
2158     * CFLAGS in place of CPPFLAGS *and* uses symbol prefixing.
2159     */
2160 #  if PNG_ARM_NEON_OPT > 0
2161 PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_neon,
2162    (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
2163 #endif
2164 
2165 #if PNG_MIPS_MSA_IMPLEMENTATION == 1
2166 PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_mips,
2167    (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
2168 #endif
2169 
2170 #  if PNG_MIPS_MMI_IMPLEMENTATION > 0
2171 PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_mips,
2172    (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
2173 #  endif
2174 
2175 #  if PNG_INTEL_SSE_IMPLEMENTATION > 0
2176 PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_sse2,
2177    (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
2178 #  endif
2179 #endif
2180 
2181 #if PNG_LOONGARCH_LSX_OPT > 0
2182 PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_lsx,
2183     (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
2184 #endif
2185 
2186 PNG_INTERNAL_FUNCTION(png_uint_32, png_check_keyword, (png_structrp png_ptr,
2187    png_const_charp key, png_bytep new_key), PNG_EMPTY);
2188 
2189 #if PNG_ARM_NEON_IMPLEMENTATION == 1
2190 PNG_INTERNAL_FUNCTION(void,
2191                       png_riffle_palette_neon,
2192                       (png_structrp),
2193                       PNG_EMPTY);
2194 PNG_INTERNAL_FUNCTION(int,
2195                       png_do_expand_palette_rgba8_neon,
2196                       (png_structrp,
2197                        png_row_infop,
2198                        png_const_bytep,
2199                        const png_bytepp,
2200                        const png_bytepp),
2201                       PNG_EMPTY);
2202 PNG_INTERNAL_FUNCTION(int,
2203                       png_do_expand_palette_rgb8_neon,
2204                       (png_structrp,
2205                        png_row_infop,
2206                        png_const_bytep,
2207                        const png_bytepp,
2208                        const png_bytepp),
2209                       PNG_EMPTY);
2210 #endif
2211 
2212 /* Maintainer: Put new private prototypes here ^ */
2213 
2214 #include "pngdebug.h"
2215 
2216 #ifdef __cplusplus
2217 }
2218 #endif
2219 
2220 #endif /* PNG_VERSION_INFO_ONLY */
2221 #endif /* PNGPRIV_H */
2222