| blob | d7c74f9bf53563e22ed634504734d45e8ac62ee5 |
2 /* pngpriv.h - private declarations for use inside libpng
3 *
4 * Copyright (c) 2018-2022 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) && defined(PNG_ALIGNED_MEMORY_SUPPORTED)
194 # define PNG_MIPS_MSA_OPT 2
195 # else
196 # define PNG_MIPS_MSA_OPT 0
197 # endif
198 #endif
200 #ifndef PNG_POWERPC_VSX_OPT
201 # if defined(__PPC64__) && defined(__ALTIVEC__) && defined(__VSX__)
202 # define PNG_POWERPC_VSX_OPT 2
203 # else
204 # define PNG_POWERPC_VSX_OPT 0
205 # endif
206 #endif
208 #ifndef PNG_INTEL_SSE_OPT
209 # ifdef PNG_INTEL_SSE
210 /* Only check for SSE if the build configuration has been modified to
211 * enable SSE optimizations. This means that these optimizations will
212 * be off by default. See contrib/intel for more details.
213 */
214 # if defined(__SSE4_1__) || defined(__AVX__) || defined(__SSSE3__) || \
215 defined(__SSE2__) || defined(_M_X64) || defined(_M_AMD64) || \
216 (defined(_M_IX86_FP) && _M_IX86_FP >= 2)
217 # define PNG_INTEL_SSE_OPT 1
218 # else
219 # define PNG_INTEL_SSE_OPT 0
220 # endif
221 # else
222 # define PNG_INTEL_SSE_OPT 0
223 # endif
224 #endif
226 #if PNG_INTEL_SSE_OPT > 0
227 # ifndef PNG_INTEL_SSE_IMPLEMENTATION
228 # if defined(__SSE4_1__) || defined(__AVX__)
229 /* We are not actually using AVX, but checking for AVX is the best
230 way we can detect SSE4.1 and SSSE3 on MSVC.
231 */
232 # define PNG_INTEL_SSE_IMPLEMENTATION 3
233 # elif defined(__SSSE3__)
234 # define PNG_INTEL_SSE_IMPLEMENTATION 2
235 # elif defined(__SSE2__) || defined(_M_X64) || defined(_M_AMD64) || \
236 (defined(_M_IX86_FP) && _M_IX86_FP >= 2)
237 # define PNG_INTEL_SSE_IMPLEMENTATION 1
238 # else
239 # define PNG_INTEL_SSE_IMPLEMENTATION 0
240 # endif
241 # endif
243 # if PNG_INTEL_SSE_IMPLEMENTATION > 0
244 # define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_sse2
245 # endif
246 #else
247 # define PNG_INTEL_SSE_IMPLEMENTATION 0
248 #endif
250 #if PNG_MIPS_MSA_OPT > 0
251 # define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_msa
252 # ifndef PNG_MIPS_MSA_IMPLEMENTATION
253 # if defined(__mips_msa)
254 # if defined(__clang__)
255 # elif defined(__GNUC__)
256 # if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 7)
257 # define PNG_MIPS_MSA_IMPLEMENTATION 2
261 # define PNG_MIPS_MSA_IMPLEMENTATION 2
265 # ifndef PNG_MIPS_MSA_IMPLEMENTATION
266 # define PNG_MIPS_MSA_IMPLEMENTATION 1
267 # endif
268 #else
269 # define PNG_MIPS_MSA_IMPLEMENTATION 0
272 #if PNG_POWERPC_VSX_OPT > 0
273 # define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_vsx
274 # define PNG_POWERPC_VSX_IMPLEMENTATION 1
275 #else
276 # define PNG_POWERPC_VSX_IMPLEMENTATION 0
277 #endif
280 /* Is this a build of a DLL where compilation of the object modules requires
281 * different preprocessor settings to those required for a simple library? If
282 * so PNG_BUILD_DLL must be set.
283 *
284 * If libpng is used inside a DLL but that DLL does not export the libpng APIs
285 * PNG_BUILD_DLL must not be set. To avoid the code below kicking in build a
286 * static library of libpng then link the DLL against that.
287 */
288 #ifndef PNG_BUILD_DLL
289 # ifdef DLL_EXPORT
290 /* This is set by libtool when files are compiled for a DLL; libtool
291 * always compiles twice, even on systems where it isn't necessary. Set
292 * PNG_BUILD_DLL in case it is necessary:
293 */
294 # define PNG_BUILD_DLL
295 # else
296 # ifdef _WINDLL
297 /* This is set by the Microsoft Visual Studio IDE in projects that
298 * build a DLL. It can't easily be removed from those projects (it
299 * isn't visible in the Visual Studio UI) so it is a fairly reliable
300 * indication that PNG_IMPEXP needs to be set to the DLL export
301 * attributes.
302 */
303 # define PNG_BUILD_DLL
304 # else
305 # ifdef __DLL__
306 /* This is set by the Borland C system when compiling for a DLL
307 * (as above.)
308 */
309 # define PNG_BUILD_DLL
310 # else
311 /* Add additional compiler cases here. */
312 # endif
313 # endif
314 # endif
317 /* See pngconf.h for more details: the builder of the library may set this on
318 * the command line to the right thing for the specific compilation system or it
319 * may be automagically set above (at present we know of no system where it does
320 * need to be set on the command line.)
321 *
322 * PNG_IMPEXP must be set here when building the library to prevent pngconf.h
323 * setting it to the "import" setting for a DLL build.
324 */
325 #ifndef PNG_IMPEXP
326 # ifdef PNG_BUILD_DLL
327 # define PNG_IMPEXP PNG_DLL_EXPORT
328 # else
329 /* Not building a DLL, or the DLL doesn't require specific export
330 * definitions.
331 */
332 # define PNG_IMPEXP
333 # endif
334 #endif
336 /* No warnings for private or deprecated functions in the build: */
337 #ifndef PNG_DEPRECATED
338 # define PNG_DEPRECATED
339 #endif
340 #ifndef PNG_PRIVATE
341 # define PNG_PRIVATE
342 #endif
344 /* Symbol preprocessing support.
345 *
346 * To enable listing global, but internal, symbols the following macros should
347 * always be used to declare an extern data or function object in this file.
348 */
349 #ifndef PNG_INTERNAL_DATA
350 # define PNG_INTERNAL_DATA(type, name, array) PNG_LINKAGE_DATA type name array
351 #endif
353 #ifndef PNG_INTERNAL_FUNCTION
354 # define PNG_INTERNAL_FUNCTION(type, name, args, attributes)\
355 PNG_LINKAGE_FUNCTION PNG_FUNCTION(type, name, args, PNG_EMPTY attributes)
356 #endif
358 #ifndef PNG_INTERNAL_CALLBACK
359 # define PNG_INTERNAL_CALLBACK(type, name, args, attributes)\
360 PNG_LINKAGE_CALLBACK PNG_FUNCTION(type, (PNGCBAPI name), args,\
361 PNG_EMPTY attributes)
362 #endif
364 /* If floating or fixed point APIs are disabled they may still be compiled
365 * internally. To handle this make sure they are declared as the appropriate
366 * internal extern function (otherwise the symbol prefixing stuff won't work and
367 * the functions will be used without definitions.)
368 *
369 * NOTE: although all the API functions are declared here they are not all
370 * actually built! Because the declarations are still made it is necessary to
371 * fake out types that they depend on.
372 */
373 #ifndef PNG_FP_EXPORT
374 # ifndef PNG_FLOATING_POINT_SUPPORTED
375 # define PNG_FP_EXPORT(ordinal, type, name, args)\
376 PNG_INTERNAL_FUNCTION(type, name, args, PNG_EMPTY);
377 # ifndef PNG_VERSION_INFO_ONLY
382 # endif
383 # endif
384 #endif
385 #ifndef PNG_FIXED_EXPORT
386 # ifndef PNG_FIXED_POINT_SUPPORTED
387 # define PNG_FIXED_EXPORT(ordinal, type, name, args)\
388 PNG_INTERNAL_FUNCTION(type, name, args, PNG_EMPTY);
389 # endif
390 #endif
394 /* pngconf.h does not set PNG_DLL_EXPORT unless it is required, so: */
395 #ifndef PNG_DLL_EXPORT
396 # define PNG_DLL_EXPORT
397 #endif
399 /* This is a global switch to set the compilation for an installed system
400 * (a release build). It can be set for testing debug builds to ensure that
401 * they will compile when the build type is switched to RC or STABLE, the
402 * default is just to use PNG_LIBPNG_BUILD_BASE_TYPE. Set this in CPPFLAGS
403 * with either:
404 *
405 * -DPNG_RELEASE_BUILD Turns on the release compile path
406 * -DPNG_RELEASE_BUILD=0 Turns it off
407 * or in your pngusr.h with
408 * #define PNG_RELEASE_BUILD=1 Turns on the release compile path
409 * #define PNG_RELEASE_BUILD=0 Turns it off
410 */
411 #ifndef PNG_RELEASE_BUILD
412 # define PNG_RELEASE_BUILD (PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC)
413 #endif
415 /* SECURITY and SAFETY:
416 *
417 * libpng is built with support for internal limits on image dimensions and
418 * memory usage. These are documented in scripts/pnglibconf.dfa of the
419 * source and recorded in the machine generated header file pnglibconf.h.
420 */
422 /* If you are running on a machine where you cannot allocate more
423 * than 64K of memory at once, uncomment this. While libpng will not
424 * normally need that much memory in a chunk (unless you load up a very
425 * large file), zlib needs to know how big of a chunk it can use, and
426 * libpng thus makes sure to check any memory allocation to verify it
427 * will fit into memory.
428 *
429 * zlib provides 'MAXSEG_64K' which, if defined, indicates the
430 * same limit and pngconf.h (already included) sets the limit
431 * if certain operating systems are detected.
432 */
433 #if defined(MAXSEG_64K) && !defined(PNG_MAX_MALLOC_64K)
434 # define PNG_MAX_MALLOC_64K
435 #endif
437 #ifndef PNG_UNUSED
438 /* Unused formal parameter warnings are silenced using the following macro
439 * which is expected to have no bad effects on performance (optimizing
440 * compilers will probably remove it entirely). Note that if you replace
441 * it with something other than whitespace, you must include the terminating
442 * semicolon.
443 */
444 # define PNG_UNUSED(param) (void)param;
445 #endif
447 /* Just a little check that someone hasn't tried to define something
448 * contradictory.
449 */
450 #if (PNG_ZBUF_SIZE > 65536L) && defined(PNG_MAX_MALLOC_64K)
451 # undef PNG_ZBUF_SIZE
452 # define PNG_ZBUF_SIZE 65536L
453 #endif
455 /* If warnings or errors are turned off the code is disabled or redirected here.
456 * From 1.5.4 functions have been added to allow very limited formatting of
457 * error and warning messages - this code will also be disabled here.
458 */
459 #ifdef PNG_WARNINGS_SUPPORTED
460 # define PNG_WARNING_PARAMETERS(p) png_warning_parameters p;
461 #else
462 # define png_warning_parameter(p,number,string) ((void)0)
463 # define png_warning_parameter_unsigned(p,number,format,value) ((void)0)
464 # define png_warning_parameter_signed(p,number,format,value) ((void)0)
465 # define png_formatted_warning(pp,p,message) ((void)(pp))
466 # define PNG_WARNING_PARAMETERS(p)
467 #endif
468 #ifndef PNG_ERROR_TEXT_SUPPORTED
469 # define png_fixed_error(s1,s2) png_err(s1)
470 #endif
472 /* Some fixed point APIs are still required even if not exported because
473 * they get used by the corresponding floating point APIs. This magic
474 * deals with this:
475 */
476 #ifdef PNG_FIXED_POINT_SUPPORTED
477 # define PNGFAPI PNGAPI
478 #else
480 #endif
482 #ifndef PNG_VERSION_INFO_ONLY
483 /* Other defines specific to compilers can go here. Try to keep
484 * them inside an appropriate ifdef/endif pair for portability.
485 */
487 /* C allows up-casts from (void*) to any pointer and (const void*) to any
488 * pointer to a const object. C++ regards this as a type error and requires an
489 * explicit, static, cast and provides the static_cast<> rune to ensure that
490 * const is not cast away.
491 */
492 #ifdef __cplusplus
493 # define png_voidcast(type, value) static_cast<type>(value)
494 # define png_constcast(type, value) const_cast<type>(value)
495 # define png_aligncast(type, value) \
496 static_cast<type>(static_cast<void*>(value))
497 # define png_aligncastconst(type, value) \
498 static_cast<type>(static_cast<const void*>(value))
499 #else
500 # define png_voidcast(type, value) (value)
501 # define png_constcast(type, value) ((type)(void*)(const void*)(value))
502 # define png_aligncast(type, value) ((void*)(value))
503 # define png_aligncastconst(type, value) ((const void*)(value))
506 #if defined(PNG_FLOATING_POINT_SUPPORTED) ||\
507 defined(PNG_FLOATING_ARITHMETIC_SUPPORTED)
508 /* png.c requires the following ANSI-C constants if the conversion of
509 * floating point to ASCII is implemented therein:
510 *
511 * DBL_DIG Maximum number of decimal digits (can be set to any constant)
512 * DBL_MIN Smallest normalized fp number (can be set to an arbitrary value)
513 * DBL_MAX Maximum floating point number (can be set to an arbitrary value)
514 */
515 # include <float.h>
517 # if (defined(__MWERKS__) && defined(macintosh)) || defined(applec) || \
518 defined(THINK_C) || defined(__SC__) || defined(TARGET_OS_MAC)
519 /* We need to check that <math.h> hasn't already been included earlier
520 * as it seems it doesn't agree with <fp.h>, yet we should really use
521 * <fp.h> if possible.
522 */
523 # if !defined(__MATH_H__) && !defined(__MATH_H) && !defined(__cmath__)
524 # include <fp.h>
525 # endif
526 # else
527 # include <math.h>
528 # endif
529 # if defined(_AMIGA) && defined(__SASC) && defined(_M68881)
530 /* Amiga SAS/C: We must include builtin FPU functions when compiling using
531 * MATH=68881
532 */
533 # include <m68881.h>
534 # endif
535 #endif
537 /* This provides the non-ANSI (far) memory allocation routines. */
538 #if defined(__TURBOC__) && defined(__MSDOS__)
539 # include <mem.h>
540 # include <alloc.h>
541 #endif
543 #if defined(_WIN32) || defined(__WIN32__) || defined(__NT__)
544 # include <windows.h>
545 #endif
548 /* Moved here around 1.5.0beta36 from pngconf.h */
549 /* Users may want to use these so they are not private. Any library
550 * functions that are passed far data must be model-independent.
551 */
553 /* Platform-independent functions */
554 #ifndef PNG_ABORT
555 # define PNG_ABORT() abort()
556 #endif
558 /* These macros may need to be architecture dependent. */
561 #ifdef offsetof
563 #else
565 #endif
568 #ifndef PNG_ALIGN_TYPE
569 /* Default to using aligned access optimizations and requiring alignment to a
570 * multiple of the data type size. Override in a compiler specific fashion
571 * if necessary by inserting tests here:
572 */
573 # define PNG_ALIGN_TYPE PNG_ALIGN_SIZE
574 #endif
576 #if PNG_ALIGN_TYPE == PNG_ALIGN_SIZE
577 /* This is used because in some compiler implementations non-aligned
578 * structure members are supported, so the offsetof approach below fails.
579 * Set PNG_ALIGN_SIZE=0 for compiler combinations where unaligned access
580 * is good for performance. Do not do this unless you have tested the
581 * result and understand it.
582 */
583 # define png_alignof(type) (sizeof(type))
584 #else
585 # if PNG_ALIGN_TYPE == PNG_ALIGN_OFFSET
586 # define png_alignof(type) offsetof(struct{char c; type t;}, t)
587 # else
588 # if PNG_ALIGN_TYPE == PNG_ALIGN_ALWAYS
589 # define png_alignof(type) 1
590 # endif
591 /* Else leave png_alignof undefined to prevent use thereof */
592 # endif
593 #endif
595 /* This implicitly assumes alignment is always a multiple of 2. */
596 #ifdef png_alignof
597 # define png_isaligned(ptr, type) \
598 (((type)(size_t)((const void*)(ptr)) & (type)(png_alignof(type)-1)) == 0)
599 #else
600 # define png_isaligned(ptr, type) 0
601 #endif
603 /* End of memory model/platform independent support */
604 /* End of 1.5.0beta36 move from pngconf.h */
606 /* CONSTANTS and UTILITY MACROS
607 * These are used internally by libpng and not exposed in the API
608 */
610 /* Various modes of operation. Note that after an init, mode is set to
611 * zero automatically when the structure is created. Three of these
612 * are defined in png.h because they need to be visible to applications
613 * that call png_set_unknown_chunk().
614 */
615 /* #define PNG_HAVE_IHDR 0x01U (defined in png.h) */
616 /* #define PNG_HAVE_PLTE 0x02U (defined in png.h) */
617 #define PNG_HAVE_IDAT 0x04U
618 /* #define PNG_AFTER_IDAT 0x08U (defined in png.h) */
619 #define PNG_HAVE_IEND 0x10U
620 /* 0x20U (unused) */
621 /* 0x40U (unused) */
622 /* 0x80U (unused) */
623 #define PNG_HAVE_CHUNK_HEADER 0x100U
624 #define PNG_WROTE_tIME 0x200U
625 #define PNG_WROTE_INFO_BEFORE_PLTE 0x400U
626 #define PNG_BACKGROUND_IS_GRAY 0x800U
627 #define PNG_HAVE_PNG_SIGNATURE 0x1000U
629 /* 0x4000U (unused) */
631 #ifdef PNG_APNG_SUPPORTED
632 #define PNG_HAVE_acTL 0x10000U
633 #define PNG_HAVE_fcTL 0x20000U
634 #endif
636 /* Flags for the transformations the PNG library does on the image data */
637 #define PNG_BGR 0x0001U
638 #define PNG_INTERLACE 0x0002U
639 #define PNG_PACK 0x0004U
640 #define PNG_SHIFT 0x0008U
641 #define PNG_SWAP_BYTES 0x0010U
642 #define PNG_INVERT_MONO 0x0020U
643 #define PNG_QUANTIZE 0x0040U
645 #define PNG_BACKGROUND_EXPAND 0x0100U
648 #define PNG_RGBA 0x0800U
649 #define PNG_EXPAND 0x1000U
650 #define PNG_GAMMA 0x2000U
651 #define PNG_GRAY_TO_RGB 0x4000U
652 #define PNG_FILLER 0x8000U
653 #define PNG_PACKSWAP 0x10000U
654 #define PNG_SWAP_ALPHA 0x20000U
655 #define PNG_STRIP_ALPHA 0x40000U
656 #define PNG_INVERT_ALPHA 0x80000U
657 #define PNG_USER_TRANSFORM 0x100000U
658 #define PNG_RGB_TO_GRAY_ERR 0x200000U
659 #define PNG_RGB_TO_GRAY_WARN 0x400000U
665 /* 0x8000000U unused */
666 /* 0x10000000U unused */
667 /* 0x20000000U unused */
668 /* 0x40000000U unused */
669 /* Flags for png_create_struct */
670 #define PNG_STRUCT_PNG 0x0001U
671 #define PNG_STRUCT_INFO 0x0002U
673 /* Flags for the png_ptr->flags rather than declaring a byte for each one */
674 #define PNG_FLAG_ZLIB_CUSTOM_STRATEGY 0x0001U
676 /* 0x0004U unused */
678 /* 0x0010U unused */
679 /* 0x0020U unused */
680 #define PNG_FLAG_ROW_INIT 0x0040U
681 #define PNG_FLAG_FILLER_AFTER 0x0080U
682 #define PNG_FLAG_CRC_ANCILLARY_USE 0x0100U
683 #define PNG_FLAG_CRC_ANCILLARY_NOWARN 0x0200U
684 #define PNG_FLAG_CRC_CRITICAL_USE 0x0400U
685 #define PNG_FLAG_CRC_CRITICAL_IGNORE 0x0800U
689 /* #define PNG_FLAG_KEEP_UNKNOWN_CHUNKS 0x8000U */
690 /* #define PNG_FLAG_KEEP_UNSAFE_CHUNKS 0x10000U */
691 #define PNG_FLAG_LIBRARY_MISMATCH 0x20000U
692 #define PNG_FLAG_STRIP_ERROR_NUMBERS 0x40000U
693 #define PNG_FLAG_STRIP_ERROR_TEXT 0x80000U
697 /* 0x800000U unused */
698 /* 0x1000000U unused */
699 /* 0x2000000U unused */
700 /* 0x4000000U unused */
701 /* 0x8000000U unused */
702 /* 0x10000000U unused */
703 /* 0x20000000U unused */
704 /* 0x40000000U unused */
706 #define PNG_FLAG_CRC_ANCILLARY_MASK (PNG_FLAG_CRC_ANCILLARY_USE | \
707 PNG_FLAG_CRC_ANCILLARY_NOWARN)
709 #define PNG_FLAG_CRC_CRITICAL_MASK (PNG_FLAG_CRC_CRITICAL_USE | \
710 PNG_FLAG_CRC_CRITICAL_IGNORE)
712 #define PNG_FLAG_CRC_MASK (PNG_FLAG_CRC_ANCILLARY_MASK | \
713 PNG_FLAG_CRC_CRITICAL_MASK)
715 /* Save typing and make code easier to understand */
717 #define PNG_COLOR_DIST(c1, c2) (abs((int)((c1).red) - (int)((c2).red)) + \
718 abs((int)((c1).green) - (int)((c2).green)) + \
719 abs((int)((c1).blue) - (int)((c2).blue)))
721 /* Added to libpng-1.6.0: scale a 16-bit value in the range 0..65535 to 0..255
722 * by dividing by 257 *with rounding*. This macro is exact for the given range.
723 * See the discourse in pngrtran.c png_do_scale_16_to_8. The values in the
724 * macro were established by experiment (modifying the added value). The macro
725 * has a second variant that takes a value already scaled by 255 and divides by
726 * 65535 - this has a maximum error of .502. Over the range 0..65535*65535 it
727 * only gives off-by-one errors and only for 0.5% (1 in 200) of the values.
728 */
729 #define PNG_DIV65535(v24) (((v24) + 32895) >> 16)
730 #define PNG_DIV257(v16) PNG_DIV65535((png_uint_32)(v16) * 255)
732 /* Added to libpng-1.2.6 JB */
733 #define PNG_ROWBYTES(pixel_bits, width) \
734 ((pixel_bits) >= 8 ? \
735 ((size_t)(width) * (((size_t)(pixel_bits)) >> 3)) : \
736 (( ((size_t)(width) * ((size_t)(pixel_bits))) + 7) >> 3) )
738 /* This returns the number of trailing bits in the last byte of a row, 0 if the
739 * last byte is completely full of pixels. It is, in principle, (pixel_bits x
740 * width) % 8, but that would overflow for large 'width'. The second macro is
741 * the same except that it returns the number of unused bits in the last byte;
742 * (8-TRAILBITS), but 0 when TRAILBITS is 0.
743 *
744 * NOTE: these macros are intended to be self-evidently correct and never
745 * overflow on the assumption that pixel_bits is in the range 0..255. The
746 * arguments are evaluated only once and they can be signed (e.g. as a result of
747 * the integral promotions). The result of the expression always has type
748 * (png_uint_32), however the compiler always knows it is in the range 0..7.
749 */
750 #define PNG_TRAILBITS(pixel_bits, width) \
751 (((pixel_bits) * ((width) % (png_uint_32)8)) % 8)
753 #define PNG_PADBITS(pixel_bits, width) \
754 ((8 - PNG_TRAILBITS(pixel_bits, width)) % 8)
756 /* PNG_OUT_OF_RANGE returns true if value is outside the range
757 * ideal-delta..ideal+delta. Each argument is evaluated twice.
758 * "ideal" and "delta" should be constants, normally simple
759 * integers, "value" a variable. Added to libpng-1.2.6 JB
760 */
761 #define PNG_OUT_OF_RANGE(value, ideal, delta) \
762 ( (value) < (ideal)-(delta) || (value) > (ideal)+(delta) )
764 /* Conversions between fixed and floating point, only defined if
765 * required (to make sure the code doesn't accidentally use float
766 * when it is supposedly disabled.)
767 */
768 #ifdef PNG_FLOATING_POINT_SUPPORTED
769 /* The floating point conversion can't overflow, though it can and
770 * does lose accuracy relative to the original fixed point value.
771 * In practice this doesn't matter because png_fixed_point only
772 * stores numbers with very low precision. The png_ptr and s
773 * arguments are unused by default but are there in case error
774 * checking becomes a requirement.
775 */
776 #define png_float(png_ptr, fixed, s) (.00001 * (fixed))
778 /* The fixed point conversion performs range checking and evaluates
779 * its argument multiple times, so must be used with care. The
780 * range checking uses the PNG specification values for a signed
781 * 32-bit fixed point value except that the values are deliberately
782 * rounded-to-zero to an integral value - 21474 (21474.83 is roughly
783 * (2^31-1) * 100000). 's' is a string that describes the value being
784 * converted.
785 *
786 * NOTE: this macro will raise a png_error if the range check fails,
787 * therefore it is normally only appropriate to use this on values
788 * that come from API calls or other sources where an out of range
789 * error indicates a programming error, not a data error!
790 *
791 * NOTE: by default this is off - the macro is not used - because the
792 * function call saves a lot of code.
793 */
794 #ifdef PNG_FIXED_POINT_MACRO_SUPPORTED
795 #define png_fixed(png_ptr, fp, s) ((fp) <= 21474 && (fp) >= -21474 ?\
796 ((png_fixed_point)(100000 * (fp))) : (png_fixed_error(png_ptr, s),0))
797 #endif
798 /* else the corresponding function is defined below, inside the scope of the
799 * cplusplus test.
800 */
801 #endif
803 /* Constants for known chunk types. If you need to add a chunk, define the name
804 * here. For historical reasons these constants have the form png_<name>; i.e.
805 * the prefix is lower case. Please use decimal values as the parameters to
806 * match the ISO PNG specification and to avoid relying on the C locale
807 * interpretation of character values.
808 *
809 * Prior to 1.5.6 these constants were strings, as of 1.5.6 png_uint_32 values
810 * are computed and a new macro (PNG_STRING_FROM_CHUNK) added to allow a string
811 * to be generated if required.
812 *
813 * PNG_32b correctly produces a value shifted by up to 24 bits, even on
814 * architectures where (int) is only 16 bits.
815 */
816 #define PNG_32b(b,s) ((png_uint_32)(b) << (s))
817 #define PNG_U32(b1,b2,b3,b4) \
818 (PNG_32b(b1,24) | PNG_32b(b2,16) | PNG_32b(b3,8) | PNG_32b(b4,0))
820 /* Constants for known chunk types.
821 *
822 * MAINTAINERS: If you need to add a chunk, define the name here.
823 * For historical reasons these constants have the form png_<name>; i.e.
824 * the prefix is lower case. Please use decimal values as the parameters to
825 * match the ISO PNG specification and to avoid relying on the C locale
826 * interpretation of character values. Please keep the list sorted.
827 *
828 * Notice that PNG_U32 is used to define a 32-bit value for the 4 byte chunk
829 * type. In fact the specification does not express chunk types this way,
830 * however using a 32-bit value means that the chunk type can be read from the
831 * stream using exactly the same code as used for a 32-bit unsigned value and
832 * can be examined far more efficiently (using one arithmetic compare).
833 *
834 * Prior to 1.5.6 the chunk type constants were expressed as C strings. The
835 * libpng API still uses strings for 'unknown' chunks and a macro,
836 * PNG_STRING_FROM_CHUNK, allows a string to be generated if required. Notice
837 * that for portable code numeric values must still be used; the string "IHDR"
838 * is not portable and neither is PNG_U32('I', 'H', 'D', 'R').
839 *
840 * In 1.7.0 the definitions will be made public in png.h to avoid having to
841 * duplicate the same definitions in application code.
842 */
843 #define png_IDAT PNG_U32( 73, 68, 65, 84)
844 #define png_IEND PNG_U32( 73, 69, 78, 68)
845 #define png_IHDR PNG_U32( 73, 72, 68, 82)
846 #define png_PLTE PNG_U32( 80, 76, 84, 69)
847 #define png_bKGD PNG_U32( 98, 75, 71, 68)
848 #define png_cHRM PNG_U32( 99, 72, 82, 77)
851 #define png_gAMA PNG_U32(103, 65, 77, 65)
852 #define png_gIFg PNG_U32(103, 73, 70, 103)
854 #define png_gIFx PNG_U32(103, 73, 70, 120)
855 #define png_hIST PNG_U32(104, 73, 83, 84)
856 #define png_iCCP PNG_U32(105, 67, 67, 80)
857 #define png_iTXt PNG_U32(105, 84, 88, 116)
858 #define png_oFFs PNG_U32(111, 70, 70, 115)
859 #define png_pCAL PNG_U32(112, 67, 65, 76)
860 #define png_pHYs PNG_U32(112, 72, 89, 115)
861 #define png_sBIT PNG_U32(115, 66, 73, 84)
862 #define png_sCAL PNG_U32(115, 67, 65, 76)
863 #define png_sPLT PNG_U32(115, 80, 76, 84)
864 #define png_sRGB PNG_U32(115, 82, 71, 66)
865 #define png_sTER PNG_U32(115, 84, 69, 82)
866 #define png_tEXt PNG_U32(116, 69, 88, 116)
867 #define png_tIME PNG_U32(116, 73, 77, 69)
868 #define png_tRNS PNG_U32(116, 82, 78, 83)
869 #define png_zTXt PNG_U32(122, 84, 88, 116)
871 #ifdef PNG_APNG_SUPPORTED
872 #define png_acTL PNG_U32( 97, 99, 84, 76)
873 #define png_fcTL PNG_U32(102, 99, 84, 76)
874 #define png_fdAT PNG_U32(102, 100, 65, 84)
876 /* For png_struct.apng_flags: */
877 #define PNG_FIRST_FRAME_HIDDEN 0x0001U
878 #define PNG_APNG_APP 0x0002U
879 #endif
881 /* The following will work on (signed char*) strings, whereas the get_uint_32
882 * macro will fail on top-bit-set values because of the sign extension.
883 */
884 #define PNG_CHUNK_FROM_STRING(s)\
885 PNG_U32(0xff & (s)[0], 0xff & (s)[1], 0xff & (s)[2], 0xff & (s)[3])
887 /* This uses (char), not (png_byte) to avoid warnings on systems where (char) is
888 * signed and the argument is a (char[]) This macro will fail miserably on
889 * systems where (char) is more than 8 bits.
890 */
891 #define PNG_STRING_FROM_CHUNK(s,c)\
892 (void)(((char*)(s))[0]=(char)(((c)>>24) & 0xff), \
893 ((char*)(s))[1]=(char)(((c)>>16) & 0xff),\
894 ((char*)(s))[2]=(char)(((c)>>8) & 0xff), \
895 ((char*)(s))[3]=(char)((c & 0xff)))
897 /* Do the same but terminate with a null character. */
898 #define PNG_CSTRING_FROM_CHUNK(s,c)\
899 (void)(PNG_STRING_FROM_CHUNK(s,c), ((char*)(s))[4] = 0)
901 /* Test on flag values as defined in the spec (section 5.4): */
902 #define PNG_CHUNK_ANCILLARY(c) (1 & ((c) >> 29))
903 #define PNG_CHUNK_CRITICAL(c) (!PNG_CHUNK_ANCILLARY(c))
904 #define PNG_CHUNK_PRIVATE(c) (1 & ((c) >> 21))
905 #define PNG_CHUNK_RESERVED(c) (1 & ((c) >> 13))
906 #define PNG_CHUNK_SAFE_TO_COPY(c) (1 & ((c) >> 5))
908 /* Gamma values (new at libpng-1.5.4): */
910 #define PNG_GAMMA_MAC_INVERSE 65909
911 #define PNG_GAMMA_sRGB_INVERSE 45455
913 /* Almost everything below is C specific; the #defines above can be used in
914 * non-C code (so long as it is C-preprocessed) the rest of this stuff cannot.
915 */
916 #ifndef PNG_VERSION_INFO_ONLY
921 /* Validate the include paths - the include path used to generate pnglibconf.h
922 * must match that used in the build, or we must be using pnglibconf.h.prebuilt:
923 */
924 #if PNG_ZLIB_VERNUM != 0 && PNG_ZLIB_VERNUM != ZLIB_VERNUM
925 # error ZLIB_VERNUM != PNG_ZLIB_VERNUM \
926 "-I (include path) error: see the notes in pngpriv.h"
927 /* This means that when pnglibconf.h was built the copy of zlib.h that it
928 * used is not the same as the one being used here. Because the build of
929 * libpng makes decisions to use inflateInit2 and inflateReset2 based on the
930 * zlib version number and because this affects handling of certain broken
931 * PNG files the -I directives must match.
932 *
933 * The most likely explanation is that you passed a -I in CFLAGS. This will
934 * not work; all the preprocessor directives and in particular all the -I
935 * directives must be in CPPFLAGS.
936 */
937 #endif
939 /* This is used for 16-bit gamma tables -- only the top level pointers are
940 * const; this could be changed:
941 */
944 /* Added to libpng-1.5.7: sRGB conversion tables */
945 #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
946 defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
947 #ifdef PNG_SIMPLIFIED_READ_SUPPORTED
949 /* Convert from an sRGB encoded value 0..255 to a 16-bit linear value,
950 * 0..65535. This table gives the closest 16-bit answers (no errors).
951 */
952 #endif
957 #define PNG_sRGB_FROM_LINEAR(linear) \
958 ((png_byte)(0xff & ((png_sRGB_base[(linear)>>15] \
959 + ((((linear) & 0x7fff)*png_sRGB_delta[(linear)>>15])>>12)) >> 8)))
960 /* Given a value 'linear' in the range 0..255*65535 calculate the 8-bit sRGB
961 * encoded value with maximum error 0.646365. Note that the input is not a
962 * 16-bit value; it has been multiplied by 255! */
966 /* Inhibit C++ name-mangling for libpng functions but not for system calls. */
967 #ifdef __cplusplus
971 /* Internal functions; these are not exported from a DLL however because they
972 * are used within several of the C source files they have to be C extern.
973 *
974 * All of these functions must be declared with PNG_INTERNAL_FUNCTION.
975 */
977 /* Zlib support */
978 #define PNG_UNEXPECTED_ZLIB_RETURN (-7)
980 PNG_EMPTY);
981 /* Used by the zlib handling functions to ensure that z_stream::msg is always
982 * set before they return.
983 */
985 #ifdef PNG_WRITE_SUPPORTED
988 /* Free the buffer list used by the compressed write code. */
989 #endif
991 #if defined(PNG_FLOATING_POINT_SUPPORTED) && \
992 !defined(PNG_FIXED_POINT_MACRO_SUPPORTED) && \
993 (defined(PNG_gAMA_SUPPORTED) || defined(PNG_cHRM_SUPPORTED) || \
994 defined(PNG_sCAL_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) || \
995 defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)) || \
996 (defined(PNG_sCAL_SUPPORTED) && \
997 defined(PNG_FLOATING_ARITHMETIC_SUPPORTED))
1000 #endif
1002 /* Check the user version string for compatibility, returns false if the version
1003 * numbers aren't compatible.
1004 */
1008 /* Internal base allocator - no messages, NULL on failure to allocate. This
1009 * does, however, call the application provided allocator and that could call
1010 * png_error (although that would be a bug in the application implementation.)
1011 */
1015 #if defined(PNG_TEXT_SUPPORTED) || defined(PNG_sPLT_SUPPORTED) ||\
1016 defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED)
1017 /* Internal array allocator, outputs no error or warning messages on failure,
1018 * just returns NULL.
1019 */
1023 /* The same but an existing array is extended by add_elements. This function
1024 * also memsets the new elements to 0 and copies the old elements. The old
1025 * array is not freed or altered.
1026 */
1032 /* Magic to create a struct when there is no struct to call the user supplied
1033 * memory allocators. Because error handling has not been set up the memory
1034 * handlers can't safely call png_error, but this is an obscure and undocumented
1035 * restriction so libpng has to assume that the 'free' handler, at least, might
1036 * call png_error.
1037 */
1043 /* Free memory from internal libpng struct */
1045 PNG_EMPTY);
1047 /* Free an allocated jmp_buf (always succeeds) */
1050 /* Function to allocate memory for zlib. PNGAPI is disallowed. */
1052 PNG_ALLOCATED);
1054 /* Function to free memory for zlib. PNGAPI is disallowed. */
1057 /* Next four functions are used internally as callbacks. PNGCBAPI is required
1058 * but not PNG_EXPORT. PNGAPI added at libpng version 1.2.3, changed to
1059 * PNGCBAPI at 1.5.0
1060 */
1065 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1068 #endif
1073 #ifdef PNG_WRITE_FLUSH_SUPPORTED
1074 # ifdef PNG_STDIO_SUPPORTED
1076 PNG_EMPTY);
1077 # endif
1078 #endif
1080 /* Reset the CRC variable */
1083 /* Write the "data" buffer to whatever output you are using */
1087 /* Read and check the PNG file signature */
1091 /* Read the chunk header (length + type name) */
1093 PNG_EMPTY);
1095 /* Read data from whatever input you are using into the "data" buffer */
1099 /* Read bytes into buf, and update png_ptr->crc */
1103 /* Read "skip" bytes, read the file crc, and (optionally) verify png_ptr->crc */
1107 /* Read the CRC from the file and compare it to the libpng calculated CRC */
1110 /* Calculate the CRC over a section of data. Note that we are only
1111 * passing a maximum of 64K on systems that have this as a memory limit,
1112 * since this is the maximum buffer size we can specify.
1113 */
1117 #ifdef PNG_WRITE_FLUSH_SUPPORTED
1119 #endif
1121 /* Write various chunks */
1123 /* Write the IHDR chunk, and update the png_struct with the necessary
1124 * information.
1125 */
1135 PNG_EMPTY);
1139 #ifdef PNG_WRITE_gAMA_SUPPORTED
1142 #endif
1144 #ifdef PNG_WRITE_sBIT_SUPPORTED
1147 #endif
1149 #ifdef PNG_WRITE_cHRM_SUPPORTED
1152 /* The xy value must have been previously validated */
1153 #endif
1155 #ifdef PNG_WRITE_sRGB_SUPPORTED
1158 #endif
1160 #ifdef PNG_WRITE_eXIf_SUPPORTED
1163 #endif
1165 #ifdef PNG_WRITE_iCCP_SUPPORTED
1168 /* The profile must have been previously validated for correctness, the
1169 * length comes from the first four bytes. Only the base, deflate,
1170 * compression is supported.
1171 */
1172 #endif
1174 #ifdef PNG_WRITE_sPLT_SUPPORTED
1177 #endif
1179 #ifdef PNG_WRITE_tRNS_SUPPORTED
1183 #endif
1185 #ifdef PNG_WRITE_bKGD_SUPPORTED
1188 #endif
1190 #ifdef PNG_WRITE_hIST_SUPPORTED
1193 #endif
1195 /* Chunks that have keywords */
1196 #ifdef PNG_WRITE_tEXt_SUPPORTED
1199 #endif
1201 #ifdef PNG_WRITE_zTXt_SUPPORTED
1204 #endif
1206 #ifdef PNG_WRITE_iTXt_SUPPORTED
1210 #endif
1215 #endif
1217 #ifdef PNG_WRITE_oFFs_SUPPORTED
1220 #endif
1222 #ifdef PNG_WRITE_pCAL_SUPPORTED
1226 #endif
1228 #ifdef PNG_WRITE_pHYs_SUPPORTED
1232 #endif
1234 #ifdef PNG_WRITE_tIME_SUPPORTED
1237 #endif
1239 #ifdef PNG_WRITE_sCAL_SUPPORTED
1242 #endif
1244 /* Called when finished processing a row of data */
1246 PNG_EMPTY);
1248 /* Internal use only. Called before first row of data */
1250 PNG_EMPTY);
1252 /* Combine a row of data, dealing with alpha, etc. if requested. 'row' is an
1253 * array of png_ptr->width pixels. If the image is not interlaced or this
1254 * is the final pass this just does a memcpy, otherwise the "display" flag
1255 * is used to determine whether to copy pixels that are not in the current pass.
1256 *
1257 * Because 'png_do_read_interlace' (below) replicates pixels this allows this
1258 * function to achieve the documented 'blocky' appearance during interlaced read
1259 * if display is 1 and the 'sparkle' appearance, where existing pixels in 'row'
1260 * are not changed if they are not in the current pass, when display is 0.
1261 *
1262 * 'display' must be 0 or 1, otherwise the memcpy will be done regardless.
1263 *
1264 * The API always reads from the png_struct row buffer and always assumes that
1265 * it is full width (png_do_read_interlace has already been called.)
1266 *
1267 * This function is only ever used to write to row buffers provided by the
1268 * caller of the relevant libpng API and the row must have already been
1269 * transformed by the read transformations.
1270 *
1271 * The PNG_USE_COMPILE_TIME_MASKS option causes generation of pre-computed
1272 * bitmasks for use within the code, otherwise runtime generated masks are used.
1273 * The default is compile time masks.
1274 */
1275 #ifndef PNG_USE_COMPILE_TIME_MASKS
1276 # define PNG_USE_COMPILE_TIME_MASKS 1
1277 #endif
1281 #ifdef PNG_READ_INTERLACING_SUPPORTED
1282 /* Expand an interlaced row: the 'row_info' describes the pass data that has
1283 * been read in and must correspond to the pixels in 'row', the pixels are
1284 * expanded (moved apart) in 'row' to match the final layout, when doing this
1285 * the pixels are *replicated* to the intervening space. This is essential for
1286 * the correct operation of png_combine_row, above.
1287 */
1290 #endif
1292 /* GRR TO DO (2.0 or whenever): simplify other internal calling interfaces */
1294 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1295 /* Grab pixels out of a row for an interlaced pass */
1298 #endif
1300 /* Unfilter a row: check the filter value before calling this, there is no point
1301 * calling it for PNG_FILTER_VALUE_NONE.
1302 */
1306 #if PNG_ARM_NEON_OPT > 0
1321 #endif
1323 #if PNG_MIPS_MSA_OPT > 0
1338 #endif
1340 #if PNG_POWERPC_VSX_OPT > 0
1355 #endif
1357 #if PNG_INTEL_SSE_IMPLEMENTATION > 0
1370 #endif
1372 /* Choose the best filter to use and filter the row data */
1376 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1379 /* Read 'avail_out' bytes of data from the IDAT stream. If the output buffer
1380 * is NULL the function checks, instead, for the end of the stream. In this
1381 * case a benign error will be issued if the stream end is not found or if
1382 * extra data has to be consumed.
1383 */
1385 PNG_EMPTY);
1386 /* This cleans up when the IDAT LZ stream does not end when the last image
1387 * byte is read; there is still some pending input.
1388 */
1391 PNG_EMPTY);
1392 /* Finish a row while reading, dealing with interlacing passes, etc. */
1395 /* Initialize the row buffers, etc. */
1398 #if ZLIB_VERNUM >= 0x1240
1400 PNG_EMPTY);
1401 # define PNG_INFLATE(pp, flush) png_zlib_inflate(pp, flush)
1403 # define PNG_INFLATE(pp, flush) inflate(&(pp)->zstream, flush)
1406 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1407 /* Optional call to update the users info structure */
1410 #endif
1412 /* Shared transform functions, defined in pngtran.c */
1413 #if defined(PNG_WRITE_FILLER_SUPPORTED) || \
1414 defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
1417 #endif
1419 #ifdef PNG_16BIT_SUPPORTED
1420 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
1423 #endif
1424 #endif
1426 #if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
1427 defined(PNG_WRITE_PACKSWAP_SUPPORTED)
1430 #endif
1432 #if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
1435 #endif
1437 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
1440 #endif
1442 /* The following decodes the appropriate chunks, and does error correction,
1443 * then calls the appropriate callback for the chunk if it is valid.
1444 */
1446 /* Decode the IHDR chunk */
1454 #ifdef PNG_READ_bKGD_SUPPORTED
1457 #endif
1459 #ifdef PNG_READ_cHRM_SUPPORTED
1462 #endif
1464 #ifdef PNG_READ_eXIf_SUPPORTED
1467 #endif
1469 #ifdef PNG_READ_gAMA_SUPPORTED
1472 #endif
1474 #ifdef PNG_READ_hIST_SUPPORTED
1477 #endif
1479 #ifdef PNG_READ_iCCP_SUPPORTED
1484 #ifdef PNG_READ_iTXt_SUPPORTED
1487 #endif
1489 #ifdef PNG_READ_oFFs_SUPPORTED
1492 #endif
1494 #ifdef PNG_READ_pCAL_SUPPORTED
1497 #endif
1499 #ifdef PNG_READ_pHYs_SUPPORTED
1502 #endif
1504 #ifdef PNG_READ_sBIT_SUPPORTED
1507 #endif
1509 #ifdef PNG_READ_sCAL_SUPPORTED
1512 #endif
1514 #ifdef PNG_READ_sPLT_SUPPORTED
1519 #ifdef PNG_READ_sRGB_SUPPORTED
1522 #endif
1524 #ifdef PNG_READ_tEXt_SUPPORTED
1527 #endif
1529 #ifdef PNG_READ_tIME_SUPPORTED
1532 #endif
1534 #ifdef PNG_READ_tRNS_SUPPORTED
1537 #endif
1539 #ifdef PNG_READ_zTXt_SUPPORTED
1542 #endif
1552 /* This is the function that gets called for unknown chunks. The 'keep'
1553 * argument is either non-zero for a known chunk that has been set to be
1554 * handled as unknown or zero for an unknown chunk. By default the function
1555 * just skips the chunk or errors out if it is critical.
1556 */
1558 #if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) ||\
1559 defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
1562 /* Exactly as the API png_handle_as_unknown() except that the argument is a
1563 * 32-bit chunk name, not a string.
1564 */
1567 /* Handle the transformations for reading and writing */
1568 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1571 #endif
1572 #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
1575 #endif
1577 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1579 PNG_EMPTY);
1580 #endif
1582 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1589 PNG_EMPTY);
1596 PNG_EMPTY);
1610 PNG_EMPTY);
1611 # ifdef PNG_READ_tEXt_SUPPORTED
1616 # endif
1617 # ifdef PNG_READ_zTXt_SUPPORTED
1622 # endif
1623 # ifdef PNG_READ_iTXt_SUPPORTED
1628 # endif
1632 #ifdef PNG_APNG_SUPPORTED
1639 #ifdef PNG_READ_APNG_SUPPORTED
1653 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1655 PNG_EMPTY);
1659 #ifdef PNG_WRITE_APNG_SUPPORTED
1675 /* Added at libpng version 1.6.0 */
1676 #ifdef PNG_GAMMA_SUPPORTED
1679 /* Set the colorspace gamma with a value provided by the application or by
1680 * the gAMA chunk on read. The value will override anything set by an ICC
1681 * profile.
1682 */
1686 /* Synchronize the info 'valid' flags with the colorspace */
1690 /* Copy the png_struct colorspace to the info_struct and call the above to
1691 * synchronize the flags. Checks for NULL info_ptr and does nothing.
1692 */
1693 #endif
1695 /* Added at libpng version 1.4.0 */
1696 #ifdef PNG_COLORSPACE_SUPPORTED
1697 /* These internal functions are for maintaining the colorspace structure within
1698 * a png_info or png_struct (or, indeed, both).
1699 */
1708 #ifdef PNG_sRGB_SUPPORTED
1711 /* This does set the colorspace gAMA and cHRM values too, but doesn't set the
1712 * flags to write them, if it returns false there was a problem and an error
1713 * message has already been output (but the colorspace may still need to be
1714 * synced to record the invalid flag).
1715 */
1718 #ifdef PNG_iCCP_SUPPORTED
1722 PNG_EMPTY);
1723 /* The 'name' is used for information only */
1725 /* Routines for checking parts of an ICC profile. */
1726 #ifdef PNG_READ_iCCP_SUPPORTED
1733 png_uint_32 profile_length,
1735 PNG_EMPTY);
1738 png_uint_32 profile_length,
1740 #ifdef PNG_sRGB_SUPPORTED
1744 /* 'adler' is the Adler32 checksum of the uncompressed profile data. It may
1745 * be zero to indicate that it is not available. It is used, if provided,
1746 * as a fast check on the profile when checking to see if it is sRGB.
1747 */
1748 #endif
1751 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1754 /* Set the rgb_to_gray coefficients from the colorspace Y values */
1758 /* Added at libpng version 1.4.0 */
1764 /* Added at libpng version 1.5.10 */
1765 #if defined(PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED) || \
1766 defined(PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED)
1769 #endif
1771 #if defined(PNG_FLOATING_POINT_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED)
1774 #endif
1776 /* Puts 'string' into 'buffer' at buffer[pos], taking care never to overwrite
1777 * the end. Always leaves the buffer nul terminated. Never errors out (and
1778 * there is no error code.)
1779 */
1783 /* Various internal functions to handle formatted warning messages, currently
1784 * only implemented for warnings.
1785 */
1786 #if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_TIME_RFC1123_SUPPORTED)
1787 /* Utility to dump an unsigned value into a buffer, given a start pointer and
1788 * and end pointer (which should point just *beyond* the end of the buffer!)
1789 * Returns the pointer to the start of the formatted string. This utility only
1790 * does unsigned values.
1791 */
1795 /* Convenience macro that takes an array: */
1796 #define PNG_FORMAT_NUMBER(buffer,format,number) \
1797 png_format_number(buffer, buffer + (sizeof buffer), format, number)
1799 /* Suggested size for a number buffer (enough for 64 bits and a sign!) */
1800 #define PNG_NUMBER_BUFFER_SIZE 24
1802 /* These are the integer formats currently supported, the name is formed from
1803 * the standard printf(3) format string.
1804 */
1806 #define PNG_NUMBER_FORMAT_02u 2
1808 #define PNG_NUMBER_FORMAT_02d 2
1809 #define PNG_NUMBER_FORMAT_x 3
1810 #define PNG_NUMBER_FORMAT_02x 4
1812 #endif
1814 #ifdef PNG_WARNINGS_SUPPORTED
1815 /* New defines and members adding in libpng-1.5.4 */
1816 # define PNG_WARNING_PARAMETER_SIZE 32
1819 /* An l-value of this type has to be passed to the APIs below to cache the
1820 * values of the parameters to a formatted warning message.
1821 */
1823 PNG_WARNING_PARAMETER_SIZE];
1827 /* Parameters are limited in size to PNG_WARNING_PARAMETER_SIZE characters,
1828 * including the trailing '\0'.
1829 */
1832 PNG_EMPTY);
1833 /* Use png_alloc_size_t because it is an unsigned type as big as any we
1834 * need to output. Use the following for a signed value.
1835 */
1838 PNG_EMPTY);
1842 /* 'message' follows the X/Open approach of using @1, @2 to insert
1843 * parameters previously supplied using the above functions. Errors in
1844 * specifying the parameters will simply result in garbage substitutions.
1845 */
1846 #endif
1848 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
1849 /* Application errors (new in 1.6); use these functions (declared below) for
1850 * errors in the parameters or order of API function calls on read. The
1851 * 'warning' should be used for an error that can be handled completely; the
1852 * 'error' for one which can be handled safely but which may lose application
1853 * information or settings.
1854 *
1855 * By default these both result in a png_error call prior to release, while in a
1856 * released version the 'warning' is just a warning. However if the application
1857 * explicitly disables benign errors (explicitly permitting the code to lose
1858 * information) they both turn into warnings.
1859 *
1860 * If benign errors aren't supported they end up as the corresponding base call
1861 * (png_warning or png_error.)
1862 */
1865 /* The application provided invalid parameters to an API function or called
1866 * an API function at the wrong time, libpng can completely recover.
1867 */
1871 /* As above but libpng will ignore the call, or attempt some other partial
1872 * recovery from the error.
1873 */
1874 #else
1875 # define png_app_warning(pp,s) png_warning(pp,s)
1876 # define png_app_error(pp,s) png_error(pp,s)
1877 #endif
1881 /* Report a recoverable issue in chunk data. On read this is used to report
1882 * a problem found while reading a particular chunk and the
1883 * png_chunk_benign_error or png_chunk_warning function is used as
1884 * appropriate. On write this is used to report an error that comes from
1885 * data set via an application call to a png_set_ API and png_app_error or
1886 * png_app_warning is used as appropriate.
1887 *
1888 * The 'error' parameter must have one of the following values:
1889 */
1894 /* ASCII to FP interfaces, currently only implemented if sCAL
1895 * support is required.
1896 */
1897 #if defined(PNG_sCAL_SUPPORTED)
1898 /* MAX_DIGITS is actually the maximum number of characters in an sCAL
1899 * width or height, derived from the precision (number of significant
1900 * digits - a build time settable option) and assumptions about the
1901 * maximum ridiculous exponent.
1902 */
1905 #ifdef PNG_FLOATING_POINT_SUPPORTED
1908 PNG_EMPTY);
1911 #ifdef PNG_FIXED_POINT_SUPPORTED
1917 #if defined(PNG_sCAL_SUPPORTED) || defined(PNG_pCAL_SUPPORTED)
1918 /* An internal API to validate the format of a floating point number.
1919 * The result is the index of the next character. If the number is
1920 * not valid it will be the index of a character in the supposed number.
1921 *
1922 * The format of a number is defined in the PNG extensions specification
1923 * and this API is strictly conformant to that spec, not anyone elses!
1924 *
1925 * The format as a regular expression is:
1926 *
1927 * [+-]?[0-9]+.?([Ee][+-]?[0-9]+)?
1928 *
1929 * or:
1930 *
1931 * [+-]?.[0-9]+(.[0-9]+)?([Ee][+-]?[0-9]+)?
1932 *
1933 * The complexity is that either integer or fraction must be present and the
1934 * fraction is permitted to have no digits only if the integer is present.
1935 *
1936 * NOTE: The dangling E problem.
1937 * There is a PNG valid floating point number in the following:
1938 *
1939 * PNG floating point numbers are not greedy.
1940 *
1941 * Working this out requires *TWO* character lookahead (because of the
1942 * sign), the parser does not do this - it will fail at the 'r' - this
1943 * doesn't matter for PNG sCAL chunk values, but it requires more care
1944 * if the value were ever to be embedded in something more complex. Use
1945 * ANSI-C strtod if you need the lookahead.
1946 */
1947 /* State table for the parser. */
1958 /* These three values don't affect the parser. They are set but not used.
1959 */
1965 /* This is available for the caller to store in 'state' if required. Do not
1966 * call the parser after setting it (the parser sometimes clears it.)
1967 */
1970 /* Result codes for the parser (boolean - true meants ok, false means
1971 * not ok yet.)
1972 */
1976 /* Tests on the sticky non-zero and negative flags. To pass these checks
1977 * the state must also indicate that the whole number is valid - this is
1978 * achieved by testing PNG_FP_SAW_DIGIT (see the implementation for why this
1979 * is equivalent to PNG_FP_OK above.)
1980 */
1981 #define PNG_FP_NZ_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NEGATIVE | PNG_FP_NONZERO)
1982 /* NZ_MASK: the string is valid and a non-zero negative value */
1983 #define PNG_FP_Z_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NONZERO)
1984 /* Z MASK: the string is valid and a non-zero value. */
1985 /* PNG_FP_SAW_DIGIT: the string is valid. */
1986 #define PNG_FP_IS_ZERO(state) (((state) & PNG_FP_Z_MASK) == PNG_FP_SAW_DIGIT)
1987 #define PNG_FP_IS_POSITIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_Z_MASK)
1988 #define PNG_FP_IS_NEGATIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_NZ_MASK)
1990 /* The actual parser. This can be called repeatedly. It updates
1991 * the index into the string and the state variable (which must
1992 * be initialized to 0). It returns a result code, as above. There
1993 * is no point calling the parser any more if it fails to advance to
1994 * the end of the string - it is stuck on an invalid character (or
1995 * terminated by '\0').
1996 *
1997 * Note that the pointer will consume an E or even an E+ and then leave
1998 * a 'maybe' state even though a preceding integer.fraction is valid.
1999 * The PNG_FP_WAS_VALID flag indicates that a preceding substring was
2000 * a valid number. It's possible to recover from this by calling
2001 * the parser again (from the start, with state 0) but with a string
2002 * that omits the last character (i.e. set the size to the index of
2003 * the problem character.) This has not been tested within libpng.
2004 */
2008 /* This is the same but it checks a complete string and returns true
2009 * only if it just contains a floating point number. As of 1.5.4 this
2010 * function also returns the state at the end of parsing the number if
2011 * it was valid (otherwise it returns 0.) This can be used for testing
2012 * for negative or zero values using the sticky flag.
2013 */
2018 #if defined(PNG_GAMMA_SUPPORTED) ||\
2019 defined(PNG_INCH_CONVERSIONS_SUPPORTED) || defined(PNG_READ_pHYs_SUPPORTED)
2020 /* Added at libpng version 1.5.0 */
2021 /* This is a utility to provide a*times/div (rounded) and indicate
2022 * if there is an overflow. The result is a boolean - false (0)
2023 * for overflow, true (1) if no overflow, in which case *res
2024 * holds the result.
2025 */
2028 #endif
2030 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_INCH_CONVERSIONS_SUPPORTED)
2031 /* Same deal, but issue a warning on overflow and return 0. */
2035 #endif
2037 #ifdef PNG_GAMMA_SUPPORTED
2038 /* Calculate a reciprocal - used for gamma values. This returns
2039 * 0 if the argument is 0 in order to maintain an undefined value;
2040 * there are no warnings.
2041 */
2043 PNG_EMPTY);
2045 #ifdef PNG_READ_GAMMA_SUPPORTED
2046 /* The same but gives a reciprocal of the product of two fixed point
2047 * values. Accuracy is suitable for gamma calculations but this is
2048 * not exact - use png_muldiv for that. Only required at present on read.
2049 */
2052 #endif
2054 /* Return true if the gamma value is significantly different from 1.0 */
2056 PNG_EMPTY);
2057 #endif
2059 #ifdef PNG_READ_GAMMA_SUPPORTED
2060 /* Internal fixed point gamma correction. These APIs are called as
2061 * required to convert single values - they don't need to be fast,
2062 * they are not used when processing image pixel values.
2063 *
2064 * While the input is an 'unsigned' value it must actually be the
2065 * correct bit value - 0..255 or 0..65535 as required.
2066 */
2074 PNG_EMPTY);
2077 #endif
2079 /* SIMPLIFIED READ/WRITE SUPPORT */
2080 #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
2081 defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
2082 /* The internal structure that png_image::opaque points to. */
2084 {
2085 png_structp png_ptr;
2086 png_infop info_ptr;
2096 /* Return the pointer to the jmp_buf from a png_control: necessary because C
2097 * does not reveal the type of the elements of jmp_buf.
2098 */
2099 #ifdef __cplusplus
2100 # define png_control_jmp_buf(pc) (((jmp_buf*)((pc)->error_buf))[0])
2101 #else
2102 # define png_control_jmp_buf(pc) ((pc)->error_buf)
2103 #endif
2105 /* Utility to safely execute a piece of libpng code catching and logging any
2106 * errors that might occur. Returns true on success, false on failure (either
2107 * of the function or as a result of a png_error.)
2108 */
2112 #ifdef PNG_WARNINGS_SUPPORTED
2115 #else
2117 #endif
2122 /* Utility to log an error; this also cleans up the png_image; the function
2123 * always returns 0 (false).
2124 */
2128 #ifndef PNG_SIMPLIFIED_READ_SUPPORTED
2129 /* png_image_free is used by the write code but not exported */
2135 /* These are initialization functions for hardware specific PNG filter
2136 * optimizations; list these here then select the appropriate one at compile
2137 * time using the macro PNG_FILTER_OPTIMIZATIONS. If the macro is not defined
2138 * the generic code is used.
2139 */
2140 #ifdef PNG_FILTER_OPTIMIZATIONS
2143 /* Just declare the optimization that will be used */
2144 #else
2145 /* List *all* the possible optimizations here - this branch is required if
2146 * the builder of libpng passes the definition of PNG_FILTER_OPTIMIZATIONS in
2147 * CFLAGS in place of CPPFLAGS *and* uses symbol prefixing.
2148 */
2149 # if PNG_ARM_NEON_OPT > 0
2152 #endif
2154 #if PNG_MIPS_MSA_OPT > 0
2157 #endif
2159 # if PNG_INTEL_SSE_IMPLEMENTATION > 0
2162 # endif
2163 #endif
2168 #if PNG_ARM_NEON_IMPLEMENTATION == 1
2170 png_riffle_palette_neon,
2172 PNG_EMPTY);
2174 png_do_expand_palette_rgba8_neon,
2176 png_row_infop,
2177 png_const_bytep,
2180 PNG_EMPTY);
2182 png_do_expand_palette_rgb8_neon,
2184 png_row_infop,
2185 png_const_bytep,
2188 PNG_EMPTY);
2189 #endif
2191 /* Maintainer: Put new private prototypes here ^ */
2195 #ifdef __cplusplus
2196 }
2197 #endif