| blob | 9bfdb71342184cb52add5dc27a78e64615130a77 |
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 */
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 */
23 #ifndef PNGPRIV_H
24 #define PNGPRIV_H
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
40 #endif
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
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>
62 /* Pick up the definition of 'restrict' from config.h if it was read: */
63 # define PNG_RESTRICT restrict
64 #endif
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
73 #endif
75 /* Local renames may change non-exported API functions from png.h */
76 #if defined(PNG_PREFIX) && !defined(PNGPREFIX_H)
78 #endif
80 #ifdef PNG_USER_CONFIG
82 /* These should have been defined in pngusr.h */
83 # ifndef PNG_USER_PRIVATEBUILD
85 # endif
86 # ifndef PNG_USER_DLLFNAME_POSTFIX
88 # endif
89 #endif
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
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
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
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
184 # ifndef PNG_ARM_NEON_IMPLEMENTATION
185 /* Use the intrinsics code by default. */
186 # define PNG_ARM_NEON_IMPLEMENTATION 1
187 # endif
189 # define PNG_ARM_NEON_IMPLEMENTATION 0
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
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
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
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
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
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
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
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
282 # define PNG_MIPS_MSA_IMPLEMENTATION 2
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
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
299 # define PNG_MIPS_MMI_IMPLEMENTATION 0
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
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
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
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
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
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
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
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
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
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
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
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
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
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 */
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
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
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
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
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
524 #endif
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 */
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))
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>
561 # include <math.h>
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
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
577 #if defined(_WIN32) || defined(__WIN32__) || defined(__NT__)
578 # include <windows.h>
579 #endif
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 */
587 /* Platform-independent functions */
588 #ifndef PNG_ABORT
589 # define PNG_ABORT() abort()
590 #endif
592 /* These macros may need to be architecture dependent. */
595 #ifdef offsetof
597 #else
599 #endif
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
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
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
637 /* End of memory model/platform independent support */
638 /* End of 1.5.0beta36 move from pngconf.h */
640 /* CONSTANTS and UTILITY MACROS
641 * These are used internally by libpng and not exposed in the API
642 */
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
663 #define PNG_WROTE_eXIf 0x4000U
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
675 #define PNG_BACKGROUND_EXPAND 0x0100U
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
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
703 /* Flags for the png_ptr->flags rather than declaring a byte for each one */
704 #define PNG_FLAG_ZLIB_CUSTOM_STRATEGY 0x0001U
706 /* 0x0004U unused */
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
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
727 /* 0x800000U unused */
728 /* 0x1000000U unused */
729 /* 0x2000000U unused */
730 /* 0x4000000U unused */
731 /* 0x8000000U unused */
732 /* 0x10000000U unused */
733 /* 0x20000000U unused */
734 /* 0x40000000U unused */
736 #define PNG_FLAG_CRC_ANCILLARY_MASK (PNG_FLAG_CRC_ANCILLARY_USE | \
737 PNG_FLAG_CRC_ANCILLARY_NOWARN)
739 #define PNG_FLAG_CRC_CRITICAL_MASK (PNG_FLAG_CRC_CRITICAL_USE | \
740 PNG_FLAG_CRC_CRITICAL_IGNORE)
742 #define PNG_FLAG_CRC_MASK (PNG_FLAG_CRC_ANCILLARY_MASK | \
743 PNG_FLAG_CRC_CRITICAL_MASK)
745 /* Save typing and make code easier to understand */
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)))
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)
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) )
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)
783 #define PNG_PADBITS(pixel_bits, width) \
784 ((8 - PNG_TRAILBITS(pixel_bits, width)) % 8)
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) )
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))
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
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))
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)
881 #define png_gAMA PNG_U32(103, 65, 77, 65)
882 #define png_gIFg PNG_U32(103, 73, 70, 103)
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)
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])
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)))
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)
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))
928 /* Gamma values (new at libpng-1.5.4): */
930 #define PNG_GAMMA_MAC_INVERSE 65909
931 #define PNG_GAMMA_sRGB_INVERSE 45455
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
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
959 /* This is used for 16-bit gamma tables -- only the top level pointers are
960 * const; this could be changed:
961 */
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
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
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! */
986 /* Inhibit C++ name-mangling for libpng functions but not for system calls. */
987 #ifdef __cplusplus
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 */
997 /* Zlib support */
998 #define PNG_UNEXPECTED_ZLIB_RETURN (-7)
1000 PNG_EMPTY);
1001 /* Used by the zlib handling functions to ensure that z_stream::msg is always
1002 * set before they return.
1003 */
1005 #ifdef PNG_WRITE_SUPPORTED
1008 /* Free the buffer list used by the compressed write code. */
1009 #endif
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))
1020 #endif
1022 /* Check the user version string for compatibility, returns false if the version
1023 * numbers aren't compatible.
1024 */
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 */
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 */
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 */
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 */
1063 /* Free memory from internal libpng struct */
1065 PNG_EMPTY);
1067 /* Free an allocated jmp_buf (always succeeds) */
1070 /* Function to allocate memory for zlib. PNGAPI is disallowed. */
1072 PNG_ALLOCATED);
1074 /* Function to free memory for zlib. PNGAPI is disallowed. */
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 */
1085 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1088 #endif
1093 #ifdef PNG_WRITE_FLUSH_SUPPORTED
1094 # ifdef PNG_STDIO_SUPPORTED
1096 PNG_EMPTY);
1097 # endif
1098 #endif
1100 /* Reset the CRC variable */
1103 /* Write the "data" buffer to whatever output you are using */
1107 /* Read and check the PNG file signature */
1111 /* Read the chunk header (length + type name) */
1113 PNG_EMPTY);
1115 /* Read data from whatever input you are using into the "data" buffer */
1119 /* Read bytes into buf, and update png_ptr->crc */
1123 /* Read "skip" bytes, read the file crc, and (optionally) verify png_ptr->crc */
1127 /* Read the CRC from the file and compare it to the libpng calculated CRC */
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 */
1137 #ifdef PNG_WRITE_FLUSH_SUPPORTED
1139 #endif
1141 /* Write various chunks */
1143 /* Write the IHDR chunk, and update the png_struct with the necessary
1144 * information.
1145 */
1155 PNG_EMPTY);
1159 #ifdef PNG_WRITE_gAMA_SUPPORTED
1162 #endif
1164 #ifdef PNG_WRITE_sBIT_SUPPORTED
1167 #endif
1169 #ifdef PNG_WRITE_cHRM_SUPPORTED
1172 /* The xy value must have been previously validated */
1173 #endif
1175 #ifdef PNG_WRITE_sRGB_SUPPORTED
1178 #endif
1180 #ifdef PNG_WRITE_eXIf_SUPPORTED
1183 #endif
1185 #ifdef PNG_WRITE_iCCP_SUPPORTED
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
1194 #ifdef PNG_WRITE_sPLT_SUPPORTED
1197 #endif
1199 #ifdef PNG_WRITE_tRNS_SUPPORTED
1203 #endif
1205 #ifdef PNG_WRITE_bKGD_SUPPORTED
1208 #endif
1210 #ifdef PNG_WRITE_hIST_SUPPORTED
1213 #endif
1215 /* Chunks that have keywords */
1216 #ifdef PNG_WRITE_tEXt_SUPPORTED
1219 #endif
1221 #ifdef PNG_WRITE_zTXt_SUPPORTED
1224 #endif
1226 #ifdef PNG_WRITE_iTXt_SUPPORTED
1230 #endif
1235 #endif
1237 #ifdef PNG_WRITE_oFFs_SUPPORTED
1240 #endif
1242 #ifdef PNG_WRITE_pCAL_SUPPORTED
1246 #endif
1248 #ifdef PNG_WRITE_pHYs_SUPPORTED
1252 #endif
1254 #ifdef PNG_WRITE_tIME_SUPPORTED
1257 #endif
1259 #ifdef PNG_WRITE_sCAL_SUPPORTED
1262 #endif
1264 /* Called when finished processing a row of data */
1266 PNG_EMPTY);
1268 /* Internal use only. Called before first row of data */
1270 PNG_EMPTY);
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
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 */
1310 #endif
1312 /* GRR TO DO (2.0 or whenever): simplify other internal calling interfaces */
1314 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1315 /* Grab pixels out of a row for an interlaced pass */
1318 #endif
1320 /* Unfilter a row: check the filter value before calling this, there is no point
1321 * calling it for PNG_FILTER_VALUE_NONE.
1322 */
1326 #if PNG_ARM_NEON_OPT > 0
1341 #endif
1343 #if PNG_MIPS_MSA_IMPLEMENTATION == 1
1358 #endif
1360 #if PNG_MIPS_MMI_IMPLEMENTATION > 0
1375 #endif
1377 #if PNG_POWERPC_VSX_OPT > 0
1392 #endif
1394 #if PNG_INTEL_SSE_IMPLEMENTATION > 0
1407 #endif
1409 #if PNG_LOONGARCH_LSX_IMPLEMENTATION == 1
1424 #endif
1426 /* Choose the best filter to use and filter the row data */
1430 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
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 */
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 */
1445 PNG_EMPTY);
1446 /* Finish a row while reading, dealing with interlacing passes, etc. */
1449 /* Initialize the row buffers, etc. */
1452 #if ZLIB_VERNUM >= 0x1240
1454 PNG_EMPTY);
1455 # define PNG_INFLATE(pp, flush) png_zlib_inflate(pp, flush)
1457 # define PNG_INFLATE(pp, flush) inflate(&(pp)->zstream, flush)
1460 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1461 /* Optional call to update the users info structure */
1464 #endif
1466 /* Shared transform functions, defined in pngtran.c */
1467 #if defined(PNG_WRITE_FILLER_SUPPORTED) || \
1468 defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
1471 #endif
1473 #ifdef PNG_16BIT_SUPPORTED
1474 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
1477 #endif
1478 #endif
1480 #if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
1481 defined(PNG_WRITE_PACKSWAP_SUPPORTED)
1484 #endif
1486 #if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
1489 #endif
1491 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
1494 #endif
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 */
1500 /* Decode the IHDR chunk */
1508 #ifdef PNG_READ_bKGD_SUPPORTED
1511 #endif
1513 #ifdef PNG_READ_cHRM_SUPPORTED
1516 #endif
1518 #ifdef PNG_READ_eXIf_SUPPORTED
1521 #endif
1523 #ifdef PNG_READ_gAMA_SUPPORTED
1526 #endif
1528 #ifdef PNG_READ_hIST_SUPPORTED
1531 #endif
1533 #ifdef PNG_READ_iCCP_SUPPORTED
1538 #ifdef PNG_READ_iTXt_SUPPORTED
1541 #endif
1543 #ifdef PNG_READ_oFFs_SUPPORTED
1546 #endif
1548 #ifdef PNG_READ_pCAL_SUPPORTED
1551 #endif
1553 #ifdef PNG_READ_pHYs_SUPPORTED
1556 #endif
1558 #ifdef PNG_READ_sBIT_SUPPORTED
1561 #endif
1563 #ifdef PNG_READ_sCAL_SUPPORTED
1566 #endif
1568 #ifdef PNG_READ_sPLT_SUPPORTED
1573 #ifdef PNG_READ_sRGB_SUPPORTED
1576 #endif
1578 #ifdef PNG_READ_tEXt_SUPPORTED
1581 #endif
1583 #ifdef PNG_READ_tIME_SUPPORTED
1586 #endif
1588 #ifdef PNG_READ_tRNS_SUPPORTED
1591 #endif
1593 #ifdef PNG_READ_zTXt_SUPPORTED
1596 #endif
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 */
1612 #if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) ||\
1613 defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
1616 /* Exactly as the API png_handle_as_unknown() except that the argument is a
1617 * 32-bit chunk name, not a string.
1618 */
1621 /* Handle the transformations for reading and writing */
1622 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1625 #endif
1626 #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
1629 #endif
1631 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1633 PNG_EMPTY);
1634 #endif
1636 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1643 PNG_EMPTY);
1650 PNG_EMPTY);
1664 PNG_EMPTY);
1665 # ifdef PNG_READ_tEXt_SUPPORTED
1670 # endif
1671 # ifdef PNG_READ_zTXt_SUPPORTED
1676 # endif
1677 # ifdef PNG_READ_iTXt_SUPPORTED
1682 # endif
1686 /* Added at libpng version 1.6.0 */
1687 #ifdef PNG_GAMMA_SUPPORTED
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 */
1697 /* Synchronize the info 'valid' flags with the colorspace */
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
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 */
1719 #ifdef PNG_sRGB_SUPPORTED
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 */
1729 #ifdef PNG_iCCP_SUPPORTED
1733 PNG_EMPTY);
1734 /* The 'name' is used for information only */
1736 /* Routines for checking parts of an ICC profile. */
1737 #ifdef PNG_READ_iCCP_SUPPORTED
1744 png_uint_32 profile_length,
1746 PNG_EMPTY);
1749 png_uint_32 profile_length,
1751 #ifdef PNG_sRGB_SUPPORTED
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
1762 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1765 /* Set the rgb_to_gray coefficients from the colorspace Y values */
1769 /* Added at libpng version 1.4.0 */
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)
1780 #endif
1782 #if defined(PNG_FLOATING_POINT_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED)
1785 #endif
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 */
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 */
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)
1810 /* Suggested size for a number buffer (enough for 64 bits and a sign!) */
1811 #define PNG_NUMBER_BUFFER_SIZE 24
1813 /* These are the integer formats currently supported, the name is formed from
1814 * the standard printf(3) format string.
1815 */
1817 #define PNG_NUMBER_FORMAT_02u 2
1819 #define PNG_NUMBER_FORMAT_02d 2
1820 #define PNG_NUMBER_FORMAT_x 3
1821 #define PNG_NUMBER_FORMAT_02x 4
1823 #endif
1825 #ifdef PNG_WARNINGS_SUPPORTED
1826 /* New defines and members adding in libpng-1.5.4 */
1827 # define PNG_WARNING_PARAMETER_SIZE 32
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 */
1834 PNG_WARNING_PARAMETER_SIZE];
1838 /* Parameters are limited in size to PNG_WARNING_PARAMETER_SIZE characters,
1839 * including the trailing '\0'.
1840 */
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 */
1849 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
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 */
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 */
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
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 */
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 */
1916 #ifdef PNG_FLOATING_POINT_SUPPORTED
1919 PNG_EMPTY);
1922 #ifdef PNG_FIXED_POINT_SUPPORTED
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. */
1969 /* These three values don't affect the parser. They are set but not used.
1970 */
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 */
1981 /* Result codes for the parser (boolean - true means ok, false means
1982 * not ok yet.)
1983 */
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)
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 */
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 */
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 */
2039 #endif
2041 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_INCH_CONVERSIONS_SUPPORTED)
2042 /* Same deal, but issue a warning on overflow and return 0. */
2046 #endif
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 */
2054 PNG_EMPTY);
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 */
2063 #endif
2065 /* Return true if the gamma value is significantly different from 1.0 */
2067 PNG_EMPTY);
2068 #endif
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 */
2085 PNG_EMPTY);
2088 #endif
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. */
2095 {
2096 png_structp png_ptr;
2097 png_infop info_ptr;
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
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 */
2123 #ifdef PNG_WARNINGS_SUPPORTED
2126 #else
2128 #endif
2133 /* Utility to log an error; this also cleans up the png_image; the function
2134 * always returns 0 (false).
2135 */
2139 #ifndef PNG_SIMPLIFIED_READ_SUPPORTED
2140 /* png_image_free is used by the write code but not exported */
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
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
2163 #endif
2165 #if PNG_MIPS_MSA_IMPLEMENTATION == 1
2168 #endif
2170 # if PNG_MIPS_MMI_IMPLEMENTATION > 0
2173 # endif
2175 # if PNG_INTEL_SSE_IMPLEMENTATION > 0
2178 # endif
2179 #endif
2181 #if PNG_LOONGARCH_LSX_OPT > 0
2184 #endif
2189 #if PNG_ARM_NEON_IMPLEMENTATION == 1
2191 png_riffle_palette_neon,
2193 PNG_EMPTY);
2195 png_do_expand_palette_rgba8_neon,
2197 png_row_infop,
2198 png_const_bytep,
2201 PNG_EMPTY);
2203 png_do_expand_palette_rgb8_neon,
2205 png_row_infop,
2206 png_const_bytep,
2209 PNG_EMPTY);
2210 #endif
2212 /* Maintainer: Put new private prototypes here ^ */
2216 #ifdef __cplusplus
2217 }
2218 #endif