2 /* pngpriv.h - private declarations for use inside libpng
4 * For conditions of distribution and use, see copyright notice in png.h
5 * Copyright (c) 1998-2013 Glenn Randers-Pehrson
6 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
7 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
9 * Last changed in libpng 1.6.0 [February 14, 2013]
11 * This code is released under the libpng license.
12 * For conditions of distribution and use, see the disclaimer
13 * and license in png.h
16 /* The symbols declared in this file (including the functions declared
17 * as extern) are PRIVATE. They are not part of the libpng public
18 * interface, and are not recommended for use by regular applications.
19 * Some of them may become public in the future; others may stay private,
20 * change in an incompatible way, or even disappear.
21 * Although the libpng users are not forbidden to include this header,
22 * they should be well aware of the issues that may arise from doing so.
28 /* Feature Test Macros. The following are defined here to ensure that correctly
29 * implemented libraries reveal the APIs libpng needs to build and hide those
30 * that are not needed and potentially damaging to the compilation.
32 * Feature Test Macros must be defined before any system header is included (see
33 * POSIX 1003.1 2.8.2 "POSIX Symbols."
35 * These macros only have an effect if the operating system supports either
36 * POSIX 1003.1 or C99, or both. On other operating systems (particularly
37 * Windows/Visual Studio) there is no effect; the OS specific tests below are
38 * still required (as of 2011-05-02.)
40 #define _POSIX_SOURCE 1 /* Just the POSIX 1003.1 and C89 APIs */
42 /* Standard library headers not required by png.h: */
46 #define PNGLIB_BUILD /*libpng is being built, not used*/
48 /* If HAVE_CONFIG_H is defined during the build then the build system must
49 * provide an appropriate "config.h" file on the include path. The header file
50 * must provide definitions as required below (search for "HAVE_CONFIG_H");
51 * see configure.ac for more details of the requirements. The macro
52 * "PNG_NO_CONFIG_H" is provided for maintainers to test for dependencies on
53 * 'configure'; define this macro to prevent the configure build including the
54 * configure generated config.h. Libpng is expected to compile without *any*
55 * special build system support on a reasonably ANSI-C compliant system.
57 #if (defined HAVE_CONFIG_H) && !(defined PNG_NO_CONFIG_H)
60 /* Pick up the definition of 'restrict' from config.h if it was read: */
61 # define PNG_RESTRICT restrict
64 /* To support symbol prefixing it is necessary to know *before* including png.h
65 * whether the fixed point (and maybe other) APIs are exported, because if they
66 * are not internal definitions may be required. This is handled below just
67 * before png.h is included, but load the configuration now if it is available.
70 # include "pnglibconf.h"
73 /* Local renames may change non-exported API functions from png.h */
74 #if defined PNG_PREFIX && !defined PNGPREFIX_H
75 # include "pngprefix.h"
78 #ifdef PNG_USER_CONFIG
80 /* These should have been defined in pngusr.h */
81 # ifndef PNG_USER_PRIVATEBUILD
82 # define PNG_USER_PRIVATEBUILD "Custom libpng build"
84 # ifndef PNG_USER_DLLFNAME_POSTFIX
85 # define PNG_USER_DLLFNAME_POSTFIX "Cb"
89 /* Is this a build of a DLL where compilation of the object modules requires
90 * different preprocessor settings to those required for a simple library? If
91 * so PNG_BUILD_DLL must be set.
93 * If libpng is used inside a DLL but that DLL does not export the libpng APIs
94 * PNG_BUILD_DLL must not be set. To avoid the code below kicking in build a
95 * static library of libpng then link the DLL against that.
99 /* This is set by libtool when files are compiled for a DLL; libtool
100 * always compiles twice, even on systems where it isn't necessary. Set
101 * PNG_BUILD_DLL in case it is necessary:
103 # define PNG_BUILD_DLL
106 /* This is set by the Microsoft Visual Studio IDE in projects that
107 * build a DLL. It can't easily be removed from those projects (it
108 * isn't visible in the Visual Studio UI) so it is a fairly reliable
109 * indication that PNG_IMPEXP needs to be set to the DLL export
112 # define PNG_BUILD_DLL
115 /* This is set by the Borland C system when compiling for a DLL
118 # define PNG_BUILD_DLL
120 /* Add additional compiler cases here. */
124 #endif /* Setting PNG_BUILD_DLL if required */
126 /* See pngconf.h for more details: the builder of the library may set this on
127 * the command line to the right thing for the specific compilation system or it
128 * may be automagically set above (at present we know of no system where it does
129 * need to be set on the command line.)
131 * PNG_IMPEXP must be set here when building the library to prevent pngconf.h
132 * setting it to the "import" setting for a DLL build.
135 # ifdef PNG_BUILD_DLL
136 # define PNG_IMPEXP PNG_DLL_EXPORT
138 /* Not building a DLL, or the DLL doesn't require specific export
145 /* No warnings for private or deprecated functions in the build: */
146 #ifndef PNG_DEPRECATED
147 # define PNG_DEPRECATED
153 /* Symbol preprocessing support.
155 * To enable listing global, but internal, symbols the following macros should
156 * always be used to declare an extern data or function object in this file.
158 #ifndef PNG_INTERNAL_DATA
159 # define PNG_INTERNAL_DATA(type, name, array) extern type name array
162 #ifndef PNG_INTERNAL_FUNCTION
163 # define PNG_INTERNAL_FUNCTION(type, name, args, attributes)\
164 extern PNG_FUNCTION(type, name, args, PNG_EMPTY attributes)
167 /* If floating or fixed point APIs are disabled they may still be compiled
168 * internally. To handle this make sure they are declared as the appropriate
169 * internal extern function (otherwise the symbol prefixing stuff won't work and
170 * the functions will be used without definitions.)
172 * NOTE: although all the API functions are declared here they are not all
173 * actually built! Because the declarations are still made it is necessary to
174 * fake out types that they depend on.
176 #ifndef PNG_FP_EXPORT
177 # ifndef PNG_FLOATING_POINT_SUPPORTED
178 # define PNG_FP_EXPORT(ordinal, type, name, args)\
179 PNG_INTERNAL_FUNCTION(type, name, args, PNG_EMPTY);
180 typedef struct png_incomplete png_double;
181 typedef png_double* png_doublep;
182 typedef const png_double* png_const_doublep;
183 typedef png_double** png_doublepp;
186 #ifndef PNG_FIXED_EXPORT
187 # ifndef PNG_FIXED_POINT_SUPPORTED
188 # define PNG_FIXED_EXPORT(ordinal, type, name, args)\
189 PNG_INTERNAL_FUNCTION(type, name, args, PNG_EMPTY);
194 #include "pngstruct.h"
197 /* pngconf.h does not set PNG_DLL_EXPORT unless it is required, so: */
198 #ifndef PNG_DLL_EXPORT
199 # define PNG_DLL_EXPORT
202 /* SECURITY and SAFETY:
204 * By default libpng is built without any internal limits on image size,
205 * individual heap (png_malloc) allocations or the total amount of memory used.
206 * If PNG_SAFE_LIMITS_SUPPORTED is defined, however, the limits below are used
207 * (unless individually overridden). These limits are believed to be fairly
208 * safe, but builders of secure systems should verify the values against the
209 * real system capabilities.
211 #ifdef PNG_SAFE_LIMITS_SUPPORTED
213 # ifndef PNG_USER_WIDTH_MAX
214 # define PNG_USER_WIDTH_MAX 1000000
216 # ifndef PNG_USER_HEIGHT_MAX
217 # define PNG_USER_HEIGHT_MAX 1000000
219 # ifndef PNG_USER_CHUNK_CACHE_MAX
220 # define PNG_USER_CHUNK_CACHE_MAX 128
222 # ifndef PNG_USER_CHUNK_MALLOC_MAX
223 # define PNG_USER_CHUNK_MALLOC_MAX 8000000
226 /* values for no limits */
227 # ifndef PNG_USER_WIDTH_MAX
228 # define PNG_USER_WIDTH_MAX 0x7fffffff
230 # ifndef PNG_USER_HEIGHT_MAX
231 # define PNG_USER_HEIGHT_MAX 0x7fffffff
233 # ifndef PNG_USER_CHUNK_CACHE_MAX
234 # define PNG_USER_CHUNK_CACHE_MAX 0
236 # ifndef PNG_USER_CHUNK_MALLOC_MAX
237 # define PNG_USER_CHUNK_MALLOC_MAX 0
241 /* This is used for 16 bit gamma tables -- only the top level pointers are
242 * const; this could be changed:
244 typedef const png_uint_16p * png_const_uint_16pp;
246 /* Moved to pngpriv.h at libpng-1.5.0 */
247 /* NOTE: some of these may have been used in external applications as
248 * these definitions were exposed in pngconf.h prior to 1.5.
251 /* If you are running on a machine where you cannot allocate more
252 * than 64K of memory at once, uncomment this. While libpng will not
253 * normally need that much memory in a chunk (unless you load up a very
254 * large file), zlib needs to know how big of a chunk it can use, and
255 * libpng thus makes sure to check any memory allocation to verify it
256 * will fit into memory.
258 * zlib provides 'MAXSEG_64K' which, if defined, indicates the
259 * same limit and pngconf.h (already included) sets the limit
260 * if certain operating systems are detected.
262 #if defined(MAXSEG_64K) && !defined(PNG_MAX_MALLOC_64K)
263 # define PNG_MAX_MALLOC_64K
267 /* Unused formal parameter warnings are silenced using the following macro
268 * which is expected to have no bad effects on performance (optimizing
269 * compilers will probably remove it entirely). Note that if you replace
270 * it with something other than whitespace, you must include the terminating
273 # define PNG_UNUSED(param) (void)param;
276 /* Just a little check that someone hasn't tried to define something
279 #if (PNG_ZBUF_SIZE > 65536L) && defined(PNG_MAX_MALLOC_64K)
280 # undef PNG_ZBUF_SIZE
281 # define PNG_ZBUF_SIZE 65536L
284 /* If warnings or errors are turned off the code is disabled or redirected here.
285 * From 1.5.4 functions have been added to allow very limited formatting of
286 * error and warning messages - this code will also be disabled here.
288 #ifdef PNG_WARNINGS_SUPPORTED
289 # define PNG_WARNING_PARAMETERS(p) png_warning_parameters p;
291 # define png_warning(s1,s2) ((void)(s1))
292 # define png_chunk_warning(s1,s2) ((void)(s1))
293 # define png_warning_parameter(p,number,string) ((void)0)
294 # define png_warning_parameter_unsigned(p,number,format,value) ((void)0)
295 # define png_warning_parameter_signed(p,number,format,value) ((void)0)
296 # define png_formatted_warning(pp,p,message) ((void)(pp))
297 # define PNG_WARNING_PARAMETERS(p)
299 #ifndef PNG_ERROR_TEXT_SUPPORTED
300 # define png_error(s1,s2) png_err(s1)
301 # define png_chunk_error(s1,s2) png_err(s1)
302 # define png_fixed_error(s1,s2) png_err(s1)
305 /* C allows up-casts from (void*) to any pointer and (const void*) to any
306 * pointer to a const object. C++ regards this as a type error and requires an
307 * explicit, static, cast and provides the static_cast<> rune to ensure that
308 * const is not cast away.
311 # define png_voidcast(type, value) static_cast<type>(value)
312 # define png_constcast(type, value) const_cast<type>(value)
313 # define png_aligncast(type, value) \
314 static_cast<type>(static_cast<void*>(value))
315 # define png_aligncastconst(type, value) \
316 static_cast<type>(static_cast<const void*>(value))
318 # define png_voidcast(type, value) (value)
319 # define png_constcast(type, value) ((type)(value))
320 # define png_aligncast(type, value) ((void*)(value))
321 # define png_aligncastconst(type, value) ((const void*)(value))
322 #endif /* __cplusplus */
324 /* Some fixed point APIs are still required even if not exported because
325 * they get used by the corresponding floating point APIs. This magic
328 #ifdef PNG_FIXED_POINT_SUPPORTED
329 # define PNGFAPI PNGAPI
331 # define PNGFAPI /* PRIVATE */
334 /* Other defines specific to compilers can go here. Try to keep
335 * them inside an appropriate ifdef/endif pair for portability.
337 #if defined(PNG_FLOATING_POINT_SUPPORTED) ||\
338 defined(PNG_FLOATING_ARITHMETIC_SUPPORTED)
339 /* png.c requires the following ANSI-C constants if the conversion of
340 * floating point to ASCII is implemented therein:
342 * DBL_DIG Maximum number of decimal digits (can be set to any constant)
343 * DBL_MIN Smallest normalized fp number (can be set to an arbitrary value)
344 * DBL_MAX Maximum floating point number (can be set to an arbitrary value)
348 # if (defined(__MWERKS__) && defined(macintosh)) || defined(applec) || \
349 defined(THINK_C) || defined(__SC__) || defined(TARGET_OS_MAC)
350 /* We need to check that <math.h> hasn't already been included earlier
351 * as it seems it doesn't agree with <fp.h>, yet we should really use
352 * <fp.h> if possible.
354 # if !defined(__MATH_H__) && !defined(__MATH_H) && !defined(__cmath__)
360 # if defined(_AMIGA) && defined(__SASC) && defined(_M68881)
361 /* Amiga SAS/C: We must include builtin FPU functions when compiling using
368 /* This provides the non-ANSI (far) memory allocation routines. */
369 #if defined(__TURBOC__) && defined(__MSDOS__)
374 #if defined(WIN32) || defined(_Windows) || defined(_WINDOWS) || \
375 defined(_WIN32) || defined(__WIN32__)
376 # include <windows.h> /* defines _WINDOWS_ macro */
379 /* Moved here around 1.5.0beta36 from pngconf.h */
380 /* Users may want to use these so they are not private. Any library
381 * functions that are passed far data must be model-independent.
384 /* Memory model/platform independent fns */
387 # define PNG_ABORT() ExitProcess(0)
389 # define PNG_ABORT() abort()
393 /* These macros may need to be architecture dependent. */
394 #define PNG_ALIGN_NONE 0 /* do not use data alignment */
395 #define PNG_ALIGN_ALWAYS 1 /* assume unaligned accesses are OK */
397 # define PNG_ALIGN_OFFSET 2 /* use offsetof to determine alignment */
399 # define PNG_ALIGN_OFFSET -1 /* prevent the use of this */
401 #define PNG_ALIGN_SIZE 3 /* use sizeof to determine alignment */
403 #ifndef PNG_ALIGN_TYPE
404 /* Default to using aligned access optimizations and requiring alignment to a
405 * multiple of the data type size. Override in a compiler specific fashion
406 * if necessary by inserting tests here:
408 # define PNG_ALIGN_TYPE PNG_ALIGN_SIZE
411 #if PNG_ALIGN_TYPE == PNG_ALIGN_SIZE
412 /* This is used because in some compiler implementations non-aligned
413 * structure members are supported, so the offsetof approach below fails.
414 * Set PNG_ALIGN_SIZE=0 for compiler combinations where unaligned access
415 * is good for performance. Do not do this unless you have tested the result
418 # define png_alignof(type) (sizeof (type))
420 # if PNG_ALIGN_TYPE == PNG_ALIGN_OFFSET
421 # define png_alignof(type) offsetof(struct{char c; type t;}, t)
423 # if PNG_ALIGN_TYPE == PNG_ALIGN_ALWAYS
424 # define png_alignof(type) (1)
426 /* Else leave png_alignof undefined to prevent use thereof */
430 /* This implicitly assumes alignment is always to a power of 2. */
432 # define png_isaligned(ptr, type)\
433 ((((const char*)ptr-(const char*)0) & (png_alignof(type)-1)) == 0)
435 # define png_isaligned(ptr, type) 0
438 /* End of memory model/platform independent support */
439 /* End of 1.5.0beta36 move from pngconf.h */
441 /* CONSTANTS and UTILITY MACROS
442 * These are used internally by libpng and not exposed in the API
445 /* Various modes of operation. Note that after an init, mode is set to
446 * zero automatically when the structure is created. Three of these
447 * are defined in png.h because they need to be visible to applications
448 * that call png_set_unknown_chunk().
450 /* #define PNG_HAVE_IHDR 0x01 (defined in png.h) */
451 /* #define PNG_HAVE_PLTE 0x02 (defined in png.h) */
452 #define PNG_HAVE_IDAT 0x04
453 /* #define PNG_AFTER_IDAT 0x08 (defined in png.h) */
454 #define PNG_HAVE_IEND 0x10
458 #define PNG_HAVE_CHUNK_HEADER 0x100
459 #define PNG_WROTE_tIME 0x200
460 #define PNG_WROTE_INFO_BEFORE_PLTE 0x400
461 #define PNG_BACKGROUND_IS_GRAY 0x800
462 #define PNG_HAVE_PNG_SIGNATURE 0x1000
463 #define PNG_HAVE_CHUNK_AFTER_IDAT 0x2000 /* Have another chunk after IDAT */
464 /* 0x4000 (unused) */
465 #define PNG_IS_READ_STRUCT 0x8000 /* Else is a write struct */
467 /* Flags for the transformations the PNG library does on the image data */
468 #define PNG_BGR 0x0001
469 #define PNG_INTERLACE 0x0002
470 #define PNG_PACK 0x0004
471 #define PNG_SHIFT 0x0008
472 #define PNG_SWAP_BYTES 0x0010
473 #define PNG_INVERT_MONO 0x0020
474 #define PNG_QUANTIZE 0x0040
475 #define PNG_COMPOSE 0x0080 /* Was PNG_BACKGROUND */
476 #define PNG_BACKGROUND_EXPAND 0x0100
477 #define PNG_EXPAND_16 0x0200 /* Added to libpng 1.5.2 */
478 #define PNG_16_TO_8 0x0400 /* Becomes 'chop' in 1.5.4 */
479 #define PNG_RGBA 0x0800
480 #define PNG_EXPAND 0x1000
481 #define PNG_GAMMA 0x2000
482 #define PNG_GRAY_TO_RGB 0x4000
483 #define PNG_FILLER 0x8000
484 #define PNG_PACKSWAP 0x10000
485 #define PNG_SWAP_ALPHA 0x20000
486 #define PNG_STRIP_ALPHA 0x40000
487 #define PNG_INVERT_ALPHA 0x80000
488 #define PNG_USER_TRANSFORM 0x100000
489 #define PNG_RGB_TO_GRAY_ERR 0x200000
490 #define PNG_RGB_TO_GRAY_WARN 0x400000
491 #define PNG_RGB_TO_GRAY 0x600000 /* two bits, RGB_TO_GRAY_ERR|WARN */
492 #define PNG_ENCODE_ALPHA 0x800000 /* Added to libpng-1.5.4 */
493 #define PNG_ADD_ALPHA 0x1000000 /* Added to libpng-1.2.7 */
494 #define PNG_EXPAND_tRNS 0x2000000 /* Added to libpng-1.2.9 */
495 #define PNG_SCALE_16_TO_8 0x4000000 /* Added to libpng-1.5.4 */
496 /* 0x8000000 unused */
497 /* 0x10000000 unused */
498 /* 0x20000000 unused */
499 /* 0x40000000 unused */
500 /* Flags for png_create_struct */
501 #define PNG_STRUCT_PNG 0x0001
502 #define PNG_STRUCT_INFO 0x0002
504 /* Scaling factor for filter heuristic weighting calculations */
505 #define PNG_WEIGHT_FACTOR (1<<(PNG_WEIGHT_SHIFT))
506 #define PNG_COST_FACTOR (1<<(PNG_COST_SHIFT))
508 /* Flags for the png_ptr->flags rather than declaring a byte for each one */
509 #define PNG_FLAG_ZLIB_CUSTOM_STRATEGY 0x0001
510 #define PNG_FLAG_ZSTREAM_INITIALIZED 0x0002 /* Added to libpng-1.6.0 */
512 #define PNG_FLAG_ZSTREAM_ENDED 0x0008 /* Added to libpng-1.6.0 */
515 #define PNG_FLAG_ROW_INIT 0x0040
516 #define PNG_FLAG_FILLER_AFTER 0x0080
517 #define PNG_FLAG_CRC_ANCILLARY_USE 0x0100
518 #define PNG_FLAG_CRC_ANCILLARY_NOWARN 0x0200
519 #define PNG_FLAG_CRC_CRITICAL_USE 0x0400
520 #define PNG_FLAG_CRC_CRITICAL_IGNORE 0x0800
521 #define PNG_FLAG_ASSUME_sRGB 0x1000 /* Added to libpng-1.5.4 */
522 #define PNG_FLAG_OPTIMIZE_ALPHA 0x2000 /* Added to libpng-1.5.4 */
523 #define PNG_FLAG_DETECT_UNINITIALIZED 0x4000 /* Added to libpng-1.5.4 */
524 /* #define PNG_FLAG_KEEP_UNKNOWN_CHUNKS 0x8000 */
525 /* #define PNG_FLAG_KEEP_UNSAFE_CHUNKS 0x10000 */
526 #define PNG_FLAG_LIBRARY_MISMATCH 0x20000
527 #define PNG_FLAG_STRIP_ERROR_NUMBERS 0x40000
528 #define PNG_FLAG_STRIP_ERROR_TEXT 0x80000
529 #define PNG_FLAG_BENIGN_ERRORS_WARN 0x100000 /* Added to libpng-1.4.0 */
530 #define PNG_FLAG_APP_WARNINGS_WARN 0x200000 /* Added to libpng-1.6.0 */
531 #define PNG_FLAG_APP_ERRORS_WARN 0x400000 /* Added to libpng-1.6.0 */
532 /* 0x800000 unused */
533 /* 0x1000000 unused */
534 /* 0x2000000 unused */
535 /* 0x4000000 unused */
536 /* 0x8000000 unused */
537 /* 0x10000000 unused */
538 /* 0x20000000 unused */
539 /* 0x40000000 unused */
541 #define PNG_FLAG_CRC_ANCILLARY_MASK (PNG_FLAG_CRC_ANCILLARY_USE | \
542 PNG_FLAG_CRC_ANCILLARY_NOWARN)
544 #define PNG_FLAG_CRC_CRITICAL_MASK (PNG_FLAG_CRC_CRITICAL_USE | \
545 PNG_FLAG_CRC_CRITICAL_IGNORE)
547 #define PNG_FLAG_CRC_MASK (PNG_FLAG_CRC_ANCILLARY_MASK | \
548 PNG_FLAG_CRC_CRITICAL_MASK)
550 /* Save typing and make code easier to understand */
552 #define PNG_COLOR_DIST(c1, c2) (abs((int)((c1).red) - (int)((c2).red)) + \
553 abs((int)((c1).green) - (int)((c2).green)) + \
554 abs((int)((c1).blue) - (int)((c2).blue)))
556 /* Added to libpng-1.5.7: sRGB conversion tables */
557 #if defined PNG_SIMPLIFIED_READ_SUPPORTED ||\
558 defined PNG_SIMPLIFIED_WRITE_SUPPORTED
559 #ifdef PNG_SIMPLIFIED_READ_SUPPORTED
560 PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_table, [256]);
561 /* Convert from an sRGB encoded value 0..255 to a 16-bit linear value,
562 * 0..65535. This table gives the closest 16-bit answers (no errors).
566 PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_base, [512]);
567 PNG_INTERNAL_DATA(const png_byte, png_sRGB_delta, [512]);
569 #define PNG_sRGB_FROM_LINEAR(linear) ((png_byte)((png_sRGB_base[(linear)>>15] +\
570 ((((linear)&0x7fff)*png_sRGB_delta[(linear)>>15])>>12)) >> 8))
571 /* Given a value 'linear' in the range 0..255*65535 calculate the 8-bit sRGB
572 * encoded value with maximum error 0.646365. Note that the input is not a
573 * 16-bit value; it has been multiplied by 255! */
574 #endif /* PNG_SIMPLIFIED_READ/WRITE */
576 /* Added to libpng-1.6.0: scale a 16-bit value in the range 0..65535 to 0..255
577 * by dividing by 257 *with rounding*. This macro is exact for the given range.
578 * See the discourse in pngrtran.c png_do_scale_16_to_8. The values in the
579 * macro were established by experiment (modifying the added value). The macro
580 * has a second variant that takes a value already scaled by 255 and divides by
581 * 65535 - this has a maximum error of .502. Over the range 0..65535*65535 it
582 * only gives off-by-one errors and only for 0.5% (1 in 200) of the values.
584 #define PNG_DIV65535(v24) (((v24) + 32895) >> 16)
585 #define PNG_DIV257(v16) PNG_DIV65535((png_uint_32)(v16) * 255)
587 /* Added to libpng-1.2.6 JB */
588 #define PNG_ROWBYTES(pixel_bits, width) \
589 ((pixel_bits) >= 8 ? \
590 ((png_size_t)(width) * (((png_size_t)(pixel_bits)) >> 3)) : \
591 (( ((png_size_t)(width) * ((png_size_t)(pixel_bits))) + 7) >> 3) )
593 /* PNG_OUT_OF_RANGE returns true if value is outside the range
594 * ideal-delta..ideal+delta. Each argument is evaluated twice.
595 * "ideal" and "delta" should be constants, normally simple
596 * integers, "value" a variable. Added to libpng-1.2.6 JB
598 #define PNG_OUT_OF_RANGE(value, ideal, delta) \
599 ( (value) < (ideal)-(delta) || (value) > (ideal)+(delta) )
601 /* Conversions between fixed and floating point, only defined if
602 * required (to make sure the code doesn't accidentally use float
603 * when it is supposedly disabled.)
605 #ifdef PNG_FLOATING_POINT_SUPPORTED
606 /* The floating point conversion can't overflow, though it can and
607 * does lose accuracy relative to the original fixed point value.
608 * In practice this doesn't matter because png_fixed_point only
609 * stores numbers with very low precision. The png_ptr and s
610 * arguments are unused by default but are there in case error
611 * checking becomes a requirement.
613 #define png_float(png_ptr, fixed, s) (.00001 * (fixed))
615 /* The fixed point conversion performs range checking and evaluates
616 * its argument multiple times, so must be used with care. The
617 * range checking uses the PNG specification values for a signed
618 * 32 bit fixed point value except that the values are deliberately
619 * rounded-to-zero to an integral value - 21474 (21474.83 is roughly
620 * (2^31-1) * 100000). 's' is a string that describes the value being
623 * NOTE: this macro will raise a png_error if the range check fails,
624 * therefore it is normally only appropriate to use this on values
625 * that come from API calls or other sources where an out of range
626 * error indicates a programming error, not a data error!
628 * NOTE: by default this is off - the macro is not used - because the
629 * function call saves a lot of code.
631 #ifdef PNG_FIXED_POINT_MACRO_SUPPORTED
632 #define png_fixed(png_ptr, fp, s) ((fp) <= 21474 && (fp) >= -21474 ?\
633 ((png_fixed_point)(100000 * (fp))) : (png_fixed_error(png_ptr, s),0))
635 /* else the corresponding function is defined below, inside the scope of the
640 /* Constants for known chunk types. If you need to add a chunk, define the name
641 * here. For historical reasons these constants have the form png_<name>; i.e.
642 * the prefix is lower case. Please use decimal values as the parameters to
643 * match the ISO PNG specification and to avoid relying on the C locale
644 * interpretation of character values.
646 * Prior to 1.5.6 these constants were strings, as of 1.5.6 png_uint_32 values
647 * are computed and a new macro (PNG_STRING_FROM_CHUNK) added to allow a string
648 * to be generated if required.
650 * PNG_32b correctly produces a value shifted by up to 24 bits, even on
651 * architectures where (int) is only 16 bits.
653 #define PNG_32b(b,s) ((png_uint_32)(b) << (s))
654 #define PNG_CHUNK(b1,b2,b3,b4) \
655 (PNG_32b(b1,24) | PNG_32b(b2,16) | PNG_32b(b3,8) | PNG_32b(b4,0))
657 #define png_IHDR PNG_CHUNK( 73, 72, 68, 82)
658 #define png_IDAT PNG_CHUNK( 73, 68, 65, 84)
659 #define png_IEND PNG_CHUNK( 73, 69, 78, 68)
660 #define png_PLTE PNG_CHUNK( 80, 76, 84, 69)
661 #define png_bKGD PNG_CHUNK( 98, 75, 71, 68)
662 #define png_cHRM PNG_CHUNK( 99, 72, 82, 77)
663 #define png_gAMA PNG_CHUNK(103, 65, 77, 65)
664 #define png_hIST PNG_CHUNK(104, 73, 83, 84)
665 #define png_iCCP PNG_CHUNK(105, 67, 67, 80)
666 #define png_iTXt PNG_CHUNK(105, 84, 88, 116)
667 #define png_oFFs PNG_CHUNK(111, 70, 70, 115)
668 #define png_pCAL PNG_CHUNK(112, 67, 65, 76)
669 #define png_sCAL PNG_CHUNK(115, 67, 65, 76)
670 #define png_pHYs PNG_CHUNK(112, 72, 89, 115)
671 #define png_sBIT PNG_CHUNK(115, 66, 73, 84)
672 #define png_sPLT PNG_CHUNK(115, 80, 76, 84)
673 #define png_sRGB PNG_CHUNK(115, 82, 71, 66)
674 #define png_sTER PNG_CHUNK(115, 84, 69, 82)
675 #define png_tEXt PNG_CHUNK(116, 69, 88, 116)
676 #define png_tIME PNG_CHUNK(116, 73, 77, 69)
677 #define png_tRNS PNG_CHUNK(116, 82, 78, 83)
678 #define png_zTXt PNG_CHUNK(122, 84, 88, 116)
680 /* The following will work on (signed char*) strings, whereas the get_uint_32
681 * macro will fail on top-bit-set values because of the sign extension.
683 #define PNG_CHUNK_FROM_STRING(s)\
684 PNG_CHUNK(0xff&(s)[0], 0xff&(s)[1], 0xff&(s)[2], 0xff&(s)[3])
686 /* This uses (char), not (png_byte) to avoid warnings on systems where (char) is
687 * signed and the argument is a (char[]) This macro will fail miserably on
688 * systems where (char) is more than 8 bits.
690 #define PNG_STRING_FROM_CHUNK(s,c)\
691 (void)(((char*)(s))[0]=(char)((c)>>24), ((char*)(s))[1]=(char)((c)>>16),\
692 ((char*)(s))[2]=(char)((c)>>8), ((char*)(s))[3]=(char)((c)))
694 /* Do the same but terminate with a null character. */
695 #define PNG_CSTRING_FROM_CHUNK(s,c)\
696 (void)(PNG_STRING_FROM_CHUNK(s,c), ((char*)(s))[4] = 0)
698 /* Test on flag values as defined in the spec (section 5.4): */
699 #define PNG_CHUNK_ANCILLIARY(c) (1 & ((c) >> 29))
700 #define PNG_CHUNK_CRITICAL(c) (!PNG_CHUNK_ANCILLIARY(c))
701 #define PNG_CHUNK_PRIVATE(c) (1 & ((c) >> 21))
702 #define PNG_CHUNK_RESERVED(c) (1 & ((c) >> 13))
703 #define PNG_CHUNK_SAFE_TO_COPY(c) (1 & ((c) >> 5))
705 /* Gamma values (new at libpng-1.5.4): */
706 #define PNG_GAMMA_MAC_OLD 151724 /* Assume '1.8' is really 2.2/1.45! */
707 #define PNG_GAMMA_MAC_INVERSE 65909
708 #define PNG_GAMMA_sRGB_INVERSE 45455
711 /* Inhibit C++ name-mangling for libpng functions but not for system calls. */
714 #endif /* __cplusplus */
716 /* Internal functions; these are not exported from a DLL however because they
717 * are used within several of the C source files they have to be C extern.
719 * All of these functions must be declared with PNG_INTERNAL_FUNCTION.
723 #define PNG_UNEXPECTED_ZLIB_RETURN (-7)
724 PNG_INTERNAL_FUNCTION(void, png_zstream_error,(png_structrp png_ptr, int ret),
726 /* Used by the zlib handling functions to ensure that z_stream::msg is always
727 * set before they return.
730 #ifdef PNG_WRITE_SUPPORTED
731 PNG_INTERNAL_FUNCTION(void,png_free_buffer_list,(png_structrp png_ptr,
732 png_compression_bufferp *list),PNG_EMPTY);
733 /* Free the buffer list used by the compressed write code. */
736 #if defined(PNG_FLOATING_POINT_SUPPORTED) && \
737 !defined(PNG_FIXED_POINT_MACRO_SUPPORTED) && \
738 (defined(PNG_gAMA_SUPPORTED) || defined(PNG_cHRM_SUPPORTED) || \
739 defined(PNG_sCAL_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) || \
740 defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)) || \
741 (defined(PNG_sCAL_SUPPORTED) && \
742 defined(PNG_FLOATING_ARITHMETIC_SUPPORTED))
743 PNG_INTERNAL_FUNCTION(png_fixed_point,png_fixed,(png_const_structrp png_ptr,
744 double fp, png_const_charp text),PNG_EMPTY);
747 /* Check the user version string for compatibility, returns false if the version
748 * numbers aren't compatible.
750 PNG_INTERNAL_FUNCTION(int,png_user_version_check,(png_structrp png_ptr,
751 png_const_charp user_png_ver),PNG_EMPTY);
753 /* Internal base allocator - no messages, NULL on failure to allocate. This
754 * does, however, call the application provided allocator and that could call
755 * png_error (although that would be a bug in the application implementation.)
757 PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_base,(png_const_structrp png_ptr,
758 png_alloc_size_t size),PNG_ALLOCATED);
760 #if defined PNG_TEXT_SUPPORTED || defined PNG_sPLT_SUPPORTED ||\
761 defined PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
762 /* Internal array allocator, outputs no error or warning messages on failure,
765 PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_array,(png_const_structrp png_ptr,
766 int nelements, size_t element_size),PNG_ALLOCATED);
768 /* The same but an existing array is extended by add_elements. This function
769 * also memsets the new elements to 0 and copies the old elements. The old
770 * array is not freed or altered.
772 PNG_INTERNAL_FUNCTION(png_voidp,png_realloc_array,(png_const_structrp png_ptr,
773 png_const_voidp array, int old_elements, int add_elements,
774 size_t element_size),PNG_ALLOCATED);
775 #endif /* text, sPLT or unknown chunks */
777 /* Magic to create a struct when there is no struct to call the user supplied
778 * memory allocators. Because error handling has not been set up the memory
779 * handlers can't safely call png_error, but this is an obscure and undocumented
780 * restriction so libpng has to assume that the 'free' handler, at least, might
783 PNG_INTERNAL_FUNCTION(png_structp,png_create_png_struct,
784 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
785 png_error_ptr warn_fn, png_voidp mem_ptr, png_malloc_ptr malloc_fn,
786 png_free_ptr free_fn),PNG_ALLOCATED);
788 /* Free memory from internal libpng struct */
789 PNG_INTERNAL_FUNCTION(void,png_destroy_png_struct,(png_structrp png_ptr),
792 /* Free an allocated jmp_buf (always succeeds) */
793 PNG_INTERNAL_FUNCTION(void,png_free_jmpbuf,(png_structrp png_ptr),PNG_EMPTY);
795 /* Function to allocate memory for zlib. PNGAPI is disallowed. */
796 PNG_INTERNAL_FUNCTION(voidpf,png_zalloc,(voidpf png_ptr, uInt items, uInt size),
799 /* Function to free memory for zlib. PNGAPI is disallowed. */
800 PNG_INTERNAL_FUNCTION(void,png_zfree,(voidpf png_ptr, voidpf ptr),PNG_EMPTY);
802 /* Next four functions are used internally as callbacks. PNGCBAPI is required
803 * but not PNG_EXPORT. PNGAPI added at libpng version 1.2.3, changed to
807 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_read_data,(png_structp png_ptr,
808 png_bytep data, png_size_t length),PNG_EMPTY);
810 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
811 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_push_fill_buffer,(png_structp png_ptr,
812 png_bytep buffer, png_size_t length),PNG_EMPTY);
815 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_write_data,(png_structp png_ptr,
816 png_bytep data, png_size_t length),PNG_EMPTY);
818 #ifdef PNG_WRITE_FLUSH_SUPPORTED
819 # ifdef PNG_STDIO_SUPPORTED
820 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_flush,(png_structp png_ptr),
825 /* Reset the CRC variable */
826 PNG_INTERNAL_FUNCTION(void,png_reset_crc,(png_structrp png_ptr),PNG_EMPTY);
828 /* Write the "data" buffer to whatever output you are using */
829 PNG_INTERNAL_FUNCTION(void,png_write_data,(png_structrp png_ptr,
830 png_const_bytep data, png_size_t length),PNG_EMPTY);
832 /* Read and check the PNG file signature */
833 PNG_INTERNAL_FUNCTION(void,png_read_sig,(png_structrp png_ptr,
834 png_inforp info_ptr),PNG_EMPTY);
836 /* Read the chunk header (length + type name) */
837 PNG_INTERNAL_FUNCTION(png_uint_32,png_read_chunk_header,(png_structrp png_ptr),
840 /* Read data from whatever input you are using into the "data" buffer */
841 PNG_INTERNAL_FUNCTION(void,png_read_data,(png_structrp png_ptr, png_bytep data,
842 png_size_t length),PNG_EMPTY);
844 /* Read bytes into buf, and update png_ptr->crc */
845 PNG_INTERNAL_FUNCTION(void,png_crc_read,(png_structrp png_ptr, png_bytep buf,
846 png_uint_32 length),PNG_EMPTY);
848 /* Read "skip" bytes, read the file crc, and (optionally) verify png_ptr->crc */
849 PNG_INTERNAL_FUNCTION(int,png_crc_finish,(png_structrp png_ptr,
850 png_uint_32 skip),PNG_EMPTY);
852 /* Read the CRC from the file and compare it to the libpng calculated CRC */
853 PNG_INTERNAL_FUNCTION(int,png_crc_error,(png_structrp png_ptr),PNG_EMPTY);
855 /* Calculate the CRC over a section of data. Note that we are only
856 * passing a maximum of 64K on systems that have this as a memory limit,
857 * since this is the maximum buffer size we can specify.
859 PNG_INTERNAL_FUNCTION(void,png_calculate_crc,(png_structrp png_ptr,
860 png_const_bytep ptr, png_size_t length),PNG_EMPTY);
862 #ifdef PNG_WRITE_FLUSH_SUPPORTED
863 PNG_INTERNAL_FUNCTION(void,png_flush,(png_structrp png_ptr),PNG_EMPTY);
866 /* Write various chunks */
868 /* Write the IHDR chunk, and update the png_struct with the necessary
871 PNG_INTERNAL_FUNCTION(void,png_write_IHDR,(png_structrp png_ptr,
872 png_uint_32 width, png_uint_32 height, int bit_depth, int color_type,
873 int compression_method, int filter_method, int interlace_method),PNG_EMPTY);
875 PNG_INTERNAL_FUNCTION(void,png_write_PLTE,(png_structrp png_ptr,
876 png_const_colorp palette, png_uint_32 num_pal),PNG_EMPTY);
878 PNG_INTERNAL_FUNCTION(void,png_compress_IDAT,(png_structrp png_ptr,
879 png_const_bytep row_data, png_alloc_size_t row_data_length, int flush),
882 PNG_INTERNAL_FUNCTION(void,png_write_IEND,(png_structrp png_ptr),PNG_EMPTY);
884 #ifdef PNG_WRITE_gAMA_SUPPORTED
885 PNG_INTERNAL_FUNCTION(void,png_write_gAMA_fixed,(png_structrp png_ptr,
886 png_fixed_point file_gamma),PNG_EMPTY);
889 #ifdef PNG_WRITE_sBIT_SUPPORTED
890 PNG_INTERNAL_FUNCTION(void,png_write_sBIT,(png_structrp png_ptr,
891 png_const_color_8p sbit, int color_type),PNG_EMPTY);
894 #ifdef PNG_WRITE_cHRM_SUPPORTED
895 PNG_INTERNAL_FUNCTION(void,png_write_cHRM_fixed,(png_structrp png_ptr,
896 const png_xy *xy), PNG_EMPTY);
897 /* The xy value must have been previously validated */
900 #ifdef PNG_WRITE_sRGB_SUPPORTED
901 PNG_INTERNAL_FUNCTION(void,png_write_sRGB,(png_structrp png_ptr,
902 int intent),PNG_EMPTY);
905 #ifdef PNG_WRITE_iCCP_SUPPORTED
906 PNG_INTERNAL_FUNCTION(void,png_write_iCCP,(png_structrp png_ptr,
907 png_const_charp name, png_const_bytep profile), PNG_EMPTY);
908 /* The profile must have been previously validated for correctness, the
909 * length comes from the first four bytes. Only the base, deflate,
910 * compression is supported.
914 #ifdef PNG_WRITE_sPLT_SUPPORTED
915 PNG_INTERNAL_FUNCTION(void,png_write_sPLT,(png_structrp png_ptr,
916 png_const_sPLT_tp palette),PNG_EMPTY);
919 #ifdef PNG_WRITE_tRNS_SUPPORTED
920 PNG_INTERNAL_FUNCTION(void,png_write_tRNS,(png_structrp png_ptr,
921 png_const_bytep trans, png_const_color_16p values, int number,
922 int color_type),PNG_EMPTY);
925 #ifdef PNG_WRITE_bKGD_SUPPORTED
926 PNG_INTERNAL_FUNCTION(void,png_write_bKGD,(png_structrp png_ptr,
927 png_const_color_16p values, int color_type),PNG_EMPTY);
930 #ifdef PNG_WRITE_hIST_SUPPORTED
931 PNG_INTERNAL_FUNCTION(void,png_write_hIST,(png_structrp png_ptr,
932 png_const_uint_16p hist, int num_hist),PNG_EMPTY);
935 /* Chunks that have keywords */
936 #ifdef PNG_WRITE_tEXt_SUPPORTED
937 PNG_INTERNAL_FUNCTION(void,png_write_tEXt,(png_structrp png_ptr,
938 png_const_charp key, png_const_charp text, png_size_t text_len),PNG_EMPTY);
941 #ifdef PNG_WRITE_zTXt_SUPPORTED
942 PNG_INTERNAL_FUNCTION(void,png_write_zTXt,(png_structrp png_ptr, png_const_charp
943 key, png_const_charp text, png_size_t text_len, int compression),PNG_EMPTY);
946 #ifdef PNG_WRITE_iTXt_SUPPORTED
947 PNG_INTERNAL_FUNCTION(void,png_write_iTXt,(png_structrp png_ptr,
948 int compression, png_const_charp key, png_const_charp lang,
949 png_const_charp lang_key, png_const_charp text),PNG_EMPTY);
952 #ifdef PNG_TEXT_SUPPORTED /* Added at version 1.0.14 and 1.2.4 */
953 PNG_INTERNAL_FUNCTION(int,png_set_text_2,(png_const_structrp png_ptr,
954 png_inforp info_ptr, png_const_textp text_ptr, int num_text),PNG_EMPTY);
957 #ifdef PNG_WRITE_oFFs_SUPPORTED
958 PNG_INTERNAL_FUNCTION(void,png_write_oFFs,(png_structrp png_ptr,
959 png_int_32 x_offset, png_int_32 y_offset, int unit_type),PNG_EMPTY);
962 #ifdef PNG_WRITE_pCAL_SUPPORTED
963 PNG_INTERNAL_FUNCTION(void,png_write_pCAL,(png_structrp png_ptr,
964 png_charp purpose, png_int_32 X0, png_int_32 X1, int type, int nparams,
965 png_const_charp units, png_charpp params),PNG_EMPTY);
968 #ifdef PNG_WRITE_pHYs_SUPPORTED
969 PNG_INTERNAL_FUNCTION(void,png_write_pHYs,(png_structrp png_ptr,
970 png_uint_32 x_pixels_per_unit, png_uint_32 y_pixels_per_unit,
971 int unit_type),PNG_EMPTY);
974 #ifdef PNG_WRITE_tIME_SUPPORTED
975 PNG_INTERNAL_FUNCTION(void,png_write_tIME,(png_structrp png_ptr,
976 png_const_timep mod_time),PNG_EMPTY);
979 #ifdef PNG_WRITE_sCAL_SUPPORTED
980 PNG_INTERNAL_FUNCTION(void,png_write_sCAL_s,(png_structrp png_ptr,
981 int unit, png_const_charp width, png_const_charp height),PNG_EMPTY);
984 /* Called when finished processing a row of data */
985 PNG_INTERNAL_FUNCTION(void,png_write_finish_row,(png_structrp png_ptr),
988 /* Internal use only. Called before first row of data */
989 PNG_INTERNAL_FUNCTION(void,png_write_start_row,(png_structrp png_ptr),
992 /* Combine a row of data, dealing with alpha, etc. if requested. 'row' is an
993 * array of png_ptr->width pixels. If the image is not interlaced or this
994 * is the final pass this just does a memcpy, otherwise the "display" flag
995 * is used to determine whether to copy pixels that are not in the current pass.
997 * Because 'png_do_read_interlace' (below) replicates pixels this allows this
998 * function to achieve the documented 'blocky' appearance during interlaced read
999 * if display is 1 and the 'sparkle' appearance, where existing pixels in 'row'
1000 * are not changed if they are not in the current pass, when display is 0.
1002 * 'display' must be 0 or 1, otherwise the memcpy will be done regardless.
1004 * The API always reads from the png_struct row buffer and always assumes that
1005 * it is full width (png_do_read_interlace has already been called.)
1007 * This function is only ever used to write to row buffers provided by the
1008 * caller of the relevant libpng API and the row must have already been
1009 * transformed by the read transformations.
1011 * The PNG_USE_COMPILE_TIME_MASKS option causes generation of pre-computed
1012 * bitmasks for use within the code, otherwise runtime generated masks are used.
1013 * The default is compile time masks.
1015 #ifndef PNG_USE_COMPILE_TIME_MASKS
1016 # define PNG_USE_COMPILE_TIME_MASKS 1
1018 PNG_INTERNAL_FUNCTION(void,png_combine_row,(png_const_structrp png_ptr,
1019 png_bytep row, int display),PNG_EMPTY);
1021 #ifdef PNG_READ_INTERLACING_SUPPORTED
1022 /* Expand an interlaced row: the 'row_info' describes the pass data that has
1023 * been read in and must correspond to the pixels in 'row', the pixels are
1024 * expanded (moved apart) in 'row' to match the final layout, when doing this
1025 * the pixels are *replicated* to the intervening space. This is essential for
1026 * the correct operation of png_combine_row, above.
1028 PNG_INTERNAL_FUNCTION(void,png_do_read_interlace,(png_row_infop row_info,
1029 png_bytep row, int pass, png_uint_32 transformations),PNG_EMPTY);
1032 /* GRR TO DO (2.0 or whenever): simplify other internal calling interfaces */
1034 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1035 /* Grab pixels out of a row for an interlaced pass */
1036 PNG_INTERNAL_FUNCTION(void,png_do_write_interlace,(png_row_infop row_info,
1037 png_bytep row, int pass),PNG_EMPTY);
1040 /* Unfilter a row: check the filter value before calling this, there is no point
1041 * calling it for PNG_FILTER_VALUE_NONE.
1043 PNG_INTERNAL_FUNCTION(void,png_read_filter_row,(png_structrp pp, png_row_infop
1044 row_info, png_bytep row, png_const_bytep prev_row, int filter),PNG_EMPTY);
1046 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_up_neon,(png_row_infop row_info,
1047 png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1048 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_neon,(png_row_infop
1049 row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1050 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_neon,(png_row_infop
1051 row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1052 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_neon,(png_row_infop
1053 row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1054 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_neon,(png_row_infop
1055 row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1056 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_neon,(png_row_infop
1057 row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1058 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_neon,(png_row_infop
1059 row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1061 /* Choose the best filter to use and filter the row data */
1062 PNG_INTERNAL_FUNCTION(void,png_write_find_filter,(png_structrp png_ptr,
1063 png_row_infop row_info),PNG_EMPTY);
1065 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1066 PNG_INTERNAL_FUNCTION(void,png_read_IDAT_data,(png_structrp png_ptr,
1067 png_bytep output, png_alloc_size_t avail_out),PNG_EMPTY);
1068 /* Read 'avail_out' bytes of data from the IDAT stream. If the output buffer
1069 * is NULL the function checks, instead, for the end of the stream. In this
1070 * case a benign error will be issued if the stream end is not found or if
1071 * extra data has to be consumed.
1073 PNG_INTERNAL_FUNCTION(void,png_read_finish_IDAT,(png_structrp png_ptr),
1075 /* This cleans up when the IDAT LZ stream does not end when the last image
1076 * byte is read; there is still some pending input.
1079 PNG_INTERNAL_FUNCTION(void,png_read_finish_row,(png_structrp png_ptr),
1081 /* Finish a row while reading, dealing with interlacing passes, etc. */
1084 /* Initialize the row buffers, etc. */
1085 PNG_INTERNAL_FUNCTION(void,png_read_start_row,(png_structrp png_ptr),PNG_EMPTY);
1087 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1088 /* Optional call to update the users info structure */
1089 PNG_INTERNAL_FUNCTION(void,png_read_transform_info,(png_structrp png_ptr,
1090 png_inforp info_ptr),PNG_EMPTY);
1093 /* These are the functions that do the transformations */
1094 #ifdef PNG_READ_FILLER_SUPPORTED
1095 PNG_INTERNAL_FUNCTION(void,png_do_read_filler,(png_row_infop row_info,
1096 png_bytep row, png_uint_32 filler, png_uint_32 flags),PNG_EMPTY);
1099 #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
1100 PNG_INTERNAL_FUNCTION(void,png_do_read_swap_alpha,(png_row_infop row_info,
1101 png_bytep row),PNG_EMPTY);
1104 #ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
1105 PNG_INTERNAL_FUNCTION(void,png_do_write_swap_alpha,(png_row_infop row_info,
1106 png_bytep row),PNG_EMPTY);
1109 #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
1110 PNG_INTERNAL_FUNCTION(void,png_do_read_invert_alpha,(png_row_infop row_info,
1111 png_bytep row),PNG_EMPTY);
1114 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
1115 PNG_INTERNAL_FUNCTION(void,png_do_write_invert_alpha,(png_row_infop row_info,
1116 png_bytep row),PNG_EMPTY);
1119 #if defined(PNG_WRITE_FILLER_SUPPORTED) || \
1120 defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
1121 PNG_INTERNAL_FUNCTION(void,png_do_strip_channel,(png_row_infop row_info,
1122 png_bytep row, int at_start),PNG_EMPTY);
1125 #ifdef PNG_16BIT_SUPPORTED
1126 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
1127 PNG_INTERNAL_FUNCTION(void,png_do_swap,(png_row_infop row_info,
1128 png_bytep row),PNG_EMPTY);
1132 #if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
1133 defined(PNG_WRITE_PACKSWAP_SUPPORTED)
1134 PNG_INTERNAL_FUNCTION(void,png_do_packswap,(png_row_infop row_info,
1135 png_bytep row),PNG_EMPTY);
1138 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1139 PNG_INTERNAL_FUNCTION(int,png_do_rgb_to_gray,(png_structrp png_ptr,
1140 png_row_infop row_info, png_bytep row),PNG_EMPTY);
1143 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
1144 PNG_INTERNAL_FUNCTION(void,png_do_gray_to_rgb,(png_row_infop row_info,
1145 png_bytep row),PNG_EMPTY);
1148 #ifdef PNG_READ_PACK_SUPPORTED
1149 PNG_INTERNAL_FUNCTION(void,png_do_unpack,(png_row_infop row_info,
1150 png_bytep row),PNG_EMPTY);
1153 #ifdef PNG_READ_SHIFT_SUPPORTED
1154 PNG_INTERNAL_FUNCTION(void,png_do_unshift,(png_row_infop row_info,
1155 png_bytep row, png_const_color_8p sig_bits),PNG_EMPTY);
1158 #if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
1159 PNG_INTERNAL_FUNCTION(void,png_do_invert,(png_row_infop row_info,
1160 png_bytep row),PNG_EMPTY);
1163 #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
1164 PNG_INTERNAL_FUNCTION(void,png_do_scale_16_to_8,(png_row_infop row_info,
1165 png_bytep row),PNG_EMPTY);
1168 #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
1169 PNG_INTERNAL_FUNCTION(void,png_do_chop,(png_row_infop row_info,
1170 png_bytep row),PNG_EMPTY);
1173 #ifdef PNG_READ_QUANTIZE_SUPPORTED
1174 PNG_INTERNAL_FUNCTION(void,png_do_quantize,(png_row_infop row_info,
1175 png_bytep row, png_const_bytep palette_lookup,
1176 png_const_bytep quantize_lookup),PNG_EMPTY);
1178 # ifdef PNG_CORRECT_PALETTE_SUPPORTED
1179 PNG_INTERNAL_FUNCTION(void,png_correct_palette,(png_structrp png_ptr,
1180 png_colorp palette, int num_palette),PNG_EMPTY);
1184 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
1185 PNG_INTERNAL_FUNCTION(void,png_do_bgr,(png_row_infop row_info,
1186 png_bytep row),PNG_EMPTY);
1189 #ifdef PNG_WRITE_PACK_SUPPORTED
1190 PNG_INTERNAL_FUNCTION(void,png_do_pack,(png_row_infop row_info,
1191 png_bytep row, png_uint_32 bit_depth),PNG_EMPTY);
1194 #ifdef PNG_WRITE_SHIFT_SUPPORTED
1195 PNG_INTERNAL_FUNCTION(void,png_do_shift,(png_row_infop row_info,
1196 png_bytep row, png_const_color_8p bit_depth),PNG_EMPTY);
1199 #if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
1200 defined(PNG_READ_ALPHA_MODE_SUPPORTED)
1201 PNG_INTERNAL_FUNCTION(void,png_do_compose,(png_row_infop row_info,
1202 png_bytep row, png_structrp png_ptr),PNG_EMPTY);
1205 #ifdef PNG_READ_GAMMA_SUPPORTED
1206 PNG_INTERNAL_FUNCTION(void,png_do_gamma,(png_row_infop row_info,
1207 png_bytep row, png_structrp png_ptr),PNG_EMPTY);
1210 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
1211 PNG_INTERNAL_FUNCTION(void,png_do_encode_alpha,(png_row_infop row_info,
1212 png_bytep row, png_structrp png_ptr),PNG_EMPTY);
1215 #ifdef PNG_READ_EXPAND_SUPPORTED
1216 PNG_INTERNAL_FUNCTION(void,png_do_expand_palette,(png_row_infop row_info,
1217 png_bytep row, png_const_colorp palette, png_const_bytep trans,
1218 int num_trans),PNG_EMPTY);
1219 PNG_INTERNAL_FUNCTION(void,png_do_expand,(png_row_infop row_info,
1220 png_bytep row, png_const_color_16p trans_color),PNG_EMPTY);
1223 #ifdef PNG_READ_EXPAND_16_SUPPORTED
1224 PNG_INTERNAL_FUNCTION(void,png_do_expand_16,(png_row_infop row_info,
1225 png_bytep row),PNG_EMPTY);
1228 /* The following decodes the appropriate chunks, and does error correction,
1229 * then calls the appropriate callback for the chunk if it is valid.
1232 /* Decode the IHDR chunk */
1233 PNG_INTERNAL_FUNCTION(void,png_handle_IHDR,(png_structrp png_ptr,
1234 png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1235 PNG_INTERNAL_FUNCTION(void,png_handle_PLTE,(png_structrp png_ptr,
1236 png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1237 PNG_INTERNAL_FUNCTION(void,png_handle_IEND,(png_structrp png_ptr,
1238 png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1240 #ifdef PNG_READ_bKGD_SUPPORTED
1241 PNG_INTERNAL_FUNCTION(void,png_handle_bKGD,(png_structrp png_ptr,
1242 png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1245 #ifdef PNG_READ_cHRM_SUPPORTED
1246 PNG_INTERNAL_FUNCTION(void,png_handle_cHRM,(png_structrp png_ptr,
1247 png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1250 #ifdef PNG_READ_gAMA_SUPPORTED
1251 PNG_INTERNAL_FUNCTION(void,png_handle_gAMA,(png_structrp png_ptr,
1252 png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1255 #ifdef PNG_READ_hIST_SUPPORTED
1256 PNG_INTERNAL_FUNCTION(void,png_handle_hIST,(png_structrp png_ptr,
1257 png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1260 #ifdef PNG_READ_iCCP_SUPPORTED
1261 PNG_INTERNAL_FUNCTION(void,png_handle_iCCP,(png_structrp png_ptr,
1262 png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1263 #endif /* PNG_READ_iCCP_SUPPORTED */
1265 #ifdef PNG_READ_iTXt_SUPPORTED
1266 PNG_INTERNAL_FUNCTION(void,png_handle_iTXt,(png_structrp png_ptr,
1267 png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1270 #ifdef PNG_READ_oFFs_SUPPORTED
1271 PNG_INTERNAL_FUNCTION(void,png_handle_oFFs,(png_structrp png_ptr,
1272 png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1275 #ifdef PNG_READ_pCAL_SUPPORTED
1276 PNG_INTERNAL_FUNCTION(void,png_handle_pCAL,(png_structrp png_ptr,
1277 png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1280 #ifdef PNG_READ_pHYs_SUPPORTED
1281 PNG_INTERNAL_FUNCTION(void,png_handle_pHYs,(png_structrp png_ptr,
1282 png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1285 #ifdef PNG_READ_sBIT_SUPPORTED
1286 PNG_INTERNAL_FUNCTION(void,png_handle_sBIT,(png_structrp png_ptr,
1287 png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1290 #ifdef PNG_READ_sCAL_SUPPORTED
1291 PNG_INTERNAL_FUNCTION(void,png_handle_sCAL,(png_structrp png_ptr,
1292 png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1295 #ifdef PNG_READ_sPLT_SUPPORTED
1296 PNG_INTERNAL_FUNCTION(void,png_handle_sPLT,(png_structrp png_ptr,
1297 png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1298 #endif /* PNG_READ_sPLT_SUPPORTED */
1300 #ifdef PNG_READ_sRGB_SUPPORTED
1301 PNG_INTERNAL_FUNCTION(void,png_handle_sRGB,(png_structrp png_ptr,
1302 png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1305 #ifdef PNG_READ_tEXt_SUPPORTED
1306 PNG_INTERNAL_FUNCTION(void,png_handle_tEXt,(png_structrp png_ptr,
1307 png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1310 #ifdef PNG_READ_tIME_SUPPORTED
1311 PNG_INTERNAL_FUNCTION(void,png_handle_tIME,(png_structrp png_ptr,
1312 png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1315 #ifdef PNG_READ_tRNS_SUPPORTED
1316 PNG_INTERNAL_FUNCTION(void,png_handle_tRNS,(png_structrp png_ptr,
1317 png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1320 #ifdef PNG_READ_zTXt_SUPPORTED
1321 PNG_INTERNAL_FUNCTION(void,png_handle_zTXt,(png_structrp png_ptr,
1322 png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1325 PNG_INTERNAL_FUNCTION(void,png_check_chunk_name,(png_structrp png_ptr,
1326 png_uint_32 chunk_name),PNG_EMPTY);
1328 #ifdef PNG_READ_SUPPORTED
1329 PNG_INTERNAL_FUNCTION(void,png_handle_unknown,(png_structrp png_ptr,
1330 png_inforp info_ptr, png_uint_32 length, int keep),PNG_EMPTY);
1331 /* This is the function that gets called for unknown chunks. The 'keep'
1332 * argument is either non-zero for a known chunk that has been set to be
1333 * handled as unknown or zero for an unknown chunk. By default the function
1334 * just skips the chunk or errors out if it is critical.
1337 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
1338 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
1339 PNG_INTERNAL_FUNCTION(int,png_chunk_unknown_handling,
1340 (png_const_structrp png_ptr, png_uint_32 chunk_name),PNG_EMPTY);
1341 /* Exactly as the API png_handle_as_unknown() except that the argument is a
1342 * 32-bit chunk name, not a string.
1345 #endif /* PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */
1346 #endif /* PNG_READ_SUPPORTED */
1348 /* Handle the transformations for reading and writing */
1349 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1350 PNG_INTERNAL_FUNCTION(void,png_do_read_transformations,(png_structrp png_ptr,
1351 png_row_infop row_info),PNG_EMPTY);
1353 #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
1354 PNG_INTERNAL_FUNCTION(void,png_do_write_transformations,(png_structrp png_ptr,
1355 png_row_infop row_info),PNG_EMPTY);
1358 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1359 PNG_INTERNAL_FUNCTION(void,png_init_read_transformations,(png_structrp png_ptr),
1363 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1364 PNG_INTERNAL_FUNCTION(void,png_push_read_chunk,(png_structrp png_ptr,
1365 png_inforp info_ptr),PNG_EMPTY);
1366 PNG_INTERNAL_FUNCTION(void,png_push_read_sig,(png_structrp png_ptr,
1367 png_inforp info_ptr),PNG_EMPTY);
1368 PNG_INTERNAL_FUNCTION(void,png_push_check_crc,(png_structrp png_ptr),PNG_EMPTY);
1369 PNG_INTERNAL_FUNCTION(void,png_push_crc_skip,(png_structrp png_ptr,
1370 png_uint_32 length),PNG_EMPTY);
1371 PNG_INTERNAL_FUNCTION(void,png_push_crc_finish,(png_structrp png_ptr),
1373 PNG_INTERNAL_FUNCTION(void,png_push_save_buffer,(png_structrp png_ptr),
1375 PNG_INTERNAL_FUNCTION(void,png_push_restore_buffer,(png_structrp png_ptr,
1376 png_bytep buffer, png_size_t buffer_length),PNG_EMPTY);
1377 PNG_INTERNAL_FUNCTION(void,png_push_read_IDAT,(png_structrp png_ptr),PNG_EMPTY);
1378 PNG_INTERNAL_FUNCTION(void,png_process_IDAT_data,(png_structrp png_ptr,
1379 png_bytep buffer, png_size_t buffer_length),PNG_EMPTY);
1380 PNG_INTERNAL_FUNCTION(void,png_push_process_row,(png_structrp png_ptr),
1382 PNG_INTERNAL_FUNCTION(void,png_push_handle_unknown,(png_structrp png_ptr,
1383 png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1384 PNG_INTERNAL_FUNCTION(void,png_push_have_info,(png_structrp png_ptr,
1385 png_inforp info_ptr),PNG_EMPTY);
1386 PNG_INTERNAL_FUNCTION(void,png_push_have_end,(png_structrp png_ptr,
1387 png_inforp info_ptr),PNG_EMPTY);
1388 PNG_INTERNAL_FUNCTION(void,png_push_have_row,(png_structrp png_ptr,
1389 png_bytep row),PNG_EMPTY);
1390 PNG_INTERNAL_FUNCTION(void,png_push_read_end,(png_structrp png_ptr,
1391 png_inforp info_ptr),PNG_EMPTY);
1392 PNG_INTERNAL_FUNCTION(void,png_process_some_data,(png_structrp png_ptr,
1393 png_inforp info_ptr),PNG_EMPTY);
1394 PNG_INTERNAL_FUNCTION(void,png_read_push_finish_row,(png_structrp png_ptr),
1396 # ifdef PNG_READ_tEXt_SUPPORTED
1397 PNG_INTERNAL_FUNCTION(void,png_push_handle_tEXt,(png_structrp png_ptr,
1398 png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1399 PNG_INTERNAL_FUNCTION(void,png_push_read_tEXt,(png_structrp png_ptr,
1400 png_inforp info_ptr),PNG_EMPTY);
1402 # ifdef PNG_READ_zTXt_SUPPORTED
1403 PNG_INTERNAL_FUNCTION(void,png_push_handle_zTXt,(png_structrp png_ptr,
1404 png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1405 PNG_INTERNAL_FUNCTION(void,png_push_read_zTXt,(png_structrp png_ptr,
1406 png_inforp info_ptr),PNG_EMPTY);
1408 # ifdef PNG_READ_iTXt_SUPPORTED
1409 PNG_INTERNAL_FUNCTION(void,png_push_handle_iTXt,(png_structrp png_ptr,
1410 png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1411 PNG_INTERNAL_FUNCTION(void,png_push_read_iTXt,(png_structrp png_ptr,
1412 png_inforp info_ptr),PNG_EMPTY);
1415 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
1417 #ifdef PNG_MNG_FEATURES_SUPPORTED
1418 PNG_INTERNAL_FUNCTION(void,png_do_read_intrapixel,(png_row_infop row_info,
1419 png_bytep row),PNG_EMPTY);
1420 PNG_INTERNAL_FUNCTION(void,png_do_write_intrapixel,(png_row_infop row_info,
1421 png_bytep row),PNG_EMPTY);
1424 /* Added at libpng version 1.6.0 */
1425 #ifdef PNG_GAMMA_SUPPORTED
1426 PNG_INTERNAL_FUNCTION(void,png_colorspace_set_gamma,(png_const_structrp png_ptr,
1427 png_colorspacerp colorspace, png_fixed_point gAMA), PNG_EMPTY);
1428 /* Set the colorspace gamma with a value provided by the application or by
1429 * the gAMA chunk on read. The value will override anything set by an ICC
1433 PNG_INTERNAL_FUNCTION(void,png_colorspace_sync_info,(png_const_structrp png_ptr,
1434 png_inforp info_ptr), PNG_EMPTY);
1435 /* Synchronize the info 'valid' flags with the colorspace */
1437 PNG_INTERNAL_FUNCTION(void,png_colorspace_sync,(png_const_structrp png_ptr,
1438 png_inforp info_ptr), PNG_EMPTY);
1439 /* Copy the png_struct colorspace to the info_struct and call the above to
1440 * synchronize the flags. Checks for NULL info_ptr and does nothing.
1444 /* Added at libpng version 1.4.0 */
1445 #ifdef PNG_COLORSPACE_SUPPORTED
1446 /* These internal functions are for maintaining the colorspace structure within
1447 * a png_info or png_struct (or, indeed, both).
1449 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_chromaticities,
1450 (png_const_structrp png_ptr, png_colorspacerp colorspace, const png_xy *xy,
1451 int preferred), PNG_EMPTY);
1453 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_endpoints,
1454 (png_const_structrp png_ptr, png_colorspacerp colorspace, const png_XYZ *XYZ,
1455 int preferred), PNG_EMPTY);
1457 #ifdef PNG_sRGB_SUPPORTED
1458 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_sRGB,(png_const_structrp png_ptr,
1459 png_colorspacerp colorspace, int intent), PNG_EMPTY);
1460 /* This does set the colorspace gAMA and cHRM values too, but doesn't set the
1461 * flags to write them, if it returns false there was a problem and an error
1462 * message has already been output (but the colorspace may still need to be
1463 * synced to record the invalid flag).
1467 #ifdef PNG_iCCP_SUPPORTED
1468 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_ICC,(png_const_structrp png_ptr,
1469 png_colorspacerp colorspace, png_const_charp name,
1470 png_uint_32 profile_length, png_const_bytep profile, int color_type),
1472 /* The 'name' is used for information only */
1474 /* Routines for checking parts of an ICC profile. */
1475 PNG_INTERNAL_FUNCTION(int,png_icc_check_length,(png_const_structrp png_ptr,
1476 png_colorspacerp colorspace, png_const_charp name,
1477 png_uint_32 profile_length), PNG_EMPTY);
1478 PNG_INTERNAL_FUNCTION(int,png_icc_check_header,(png_const_structrp png_ptr,
1479 png_colorspacerp colorspace, png_const_charp name,
1480 png_uint_32 profile_length,
1481 png_const_bytep profile /* first 132 bytes only */, int color_type),
1483 PNG_INTERNAL_FUNCTION(int,png_icc_check_tag_table,(png_const_structrp png_ptr,
1484 png_colorspacerp colorspace, png_const_charp name,
1485 png_uint_32 profile_length,
1486 png_const_bytep profile /* header plus whole tag table */), PNG_EMPTY);
1487 #ifdef PNG_sRGB_SUPPORTED
1488 PNG_INTERNAL_FUNCTION(void,png_icc_set_sRGB,(
1489 png_const_structrp png_ptr, png_colorspacerp colorspace,
1490 png_const_bytep profile, uLong adler), PNG_EMPTY);
1491 /* 'adler' is the Adler32 checksum of the uncompressed profile data. It may
1492 * be zero to indicate that it is not available. It is used, if provided,
1493 * as a fast check on the profile when checking to see if it is sRGB.
1498 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1499 PNG_INTERNAL_FUNCTION(void,png_colorspace_set_rgb_coefficients,
1500 (png_structrp png_ptr), PNG_EMPTY);
1501 /* Set the rgb_to_gray coefficients from the colorspace Y values */
1502 #endif /* READ_RGB_TO_GRAY */
1503 #endif /* COLORSPACE */
1505 /* Added at libpng version 1.4.0 */
1506 PNG_INTERNAL_FUNCTION(void,png_check_IHDR,(png_const_structrp png_ptr,
1507 png_uint_32 width, png_uint_32 height, int bit_depth,
1508 int color_type, int interlace_type, int compression_type,
1509 int filter_type),PNG_EMPTY);
1511 /* Added at libpng version 1.5.10 */
1512 #if defined(PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED) || \
1513 defined(PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED)
1514 PNG_INTERNAL_FUNCTION(void,png_do_check_palette_indexes,
1515 (png_structrp png_ptr, png_row_infop row_info),PNG_EMPTY);
1518 #if defined(PNG_FLOATING_POINT_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED)
1519 PNG_INTERNAL_FUNCTION(void,png_fixed_error,(png_const_structrp png_ptr,
1520 png_const_charp name),PNG_NORETURN);
1523 /* Puts 'string' into 'buffer' at buffer[pos], taking care never to overwrite
1524 * the end. Always leaves the buffer nul terminated. Never errors out (and
1525 * there is no error code.)
1527 PNG_INTERNAL_FUNCTION(size_t,png_safecat,(png_charp buffer, size_t bufsize,
1528 size_t pos, png_const_charp string),PNG_EMPTY);
1530 /* Various internal functions to handle formatted warning messages, currently
1531 * only implemented for warnings.
1533 #if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_TIME_RFC1123_SUPPORTED)
1534 /* Utility to dump an unsigned value into a buffer, given a start pointer and
1535 * and end pointer (which should point just *beyond* the end of the buffer!)
1536 * Returns the pointer to the start of the formatted string. This utility only
1537 * does unsigned values.
1539 PNG_INTERNAL_FUNCTION(png_charp,png_format_number,(png_const_charp start,
1540 png_charp end, int format, png_alloc_size_t number),PNG_EMPTY);
1542 /* Convenience macro that takes an array: */
1543 #define PNG_FORMAT_NUMBER(buffer,format,number) \
1544 png_format_number(buffer, buffer + (sizeof buffer), format, number)
1546 /* Suggested size for a number buffer (enough for 64 bits and a sign!) */
1547 #define PNG_NUMBER_BUFFER_SIZE 24
1549 /* These are the integer formats currently supported, the name is formed from
1550 * the standard printf(3) format string.
1552 #define PNG_NUMBER_FORMAT_u 1 /* chose unsigned API! */
1553 #define PNG_NUMBER_FORMAT_02u 2
1554 #define PNG_NUMBER_FORMAT_d 1 /* chose signed API! */
1555 #define PNG_NUMBER_FORMAT_02d 2
1556 #define PNG_NUMBER_FORMAT_x 3
1557 #define PNG_NUMBER_FORMAT_02x 4
1558 #define PNG_NUMBER_FORMAT_fixed 5 /* choose the signed API */
1561 #ifdef PNG_WARNINGS_SUPPORTED
1562 /* New defines and members adding in libpng-1.5.4 */
1563 # define PNG_WARNING_PARAMETER_SIZE 32
1564 # define PNG_WARNING_PARAMETER_COUNT 8 /* Maximum 9; see pngerror.c */
1566 /* An l-value of this type has to be passed to the APIs below to cache the
1567 * values of the parameters to a formatted warning message.
1569 typedef char png_warning_parameters[PNG_WARNING_PARAMETER_COUNT][
1570 PNG_WARNING_PARAMETER_SIZE];
1572 PNG_INTERNAL_FUNCTION(void,png_warning_parameter,(png_warning_parameters p,
1573 int number, png_const_charp string),PNG_EMPTY);
1574 /* Parameters are limited in size to PNG_WARNING_PARAMETER_SIZE characters,
1575 * including the trailing '\0'.
1577 PNG_INTERNAL_FUNCTION(void,png_warning_parameter_unsigned,
1578 (png_warning_parameters p, int number, int format, png_alloc_size_t value),
1580 /* Use png_alloc_size_t because it is an unsigned type as big as any we
1581 * need to output. Use the following for a signed value.
1583 PNG_INTERNAL_FUNCTION(void,png_warning_parameter_signed,
1584 (png_warning_parameters p, int number, int format, png_int_32 value),
1587 PNG_INTERNAL_FUNCTION(void,png_formatted_warning,(png_const_structrp png_ptr,
1588 png_warning_parameters p, png_const_charp message),PNG_EMPTY);
1589 /* 'message' follows the X/Open approach of using @1, @2 to insert
1590 * parameters previously supplied using the above functions. Errors in
1591 * specifying the parameters will simply result in garbage substitutions.
1595 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
1596 /* Application errors (new in 1.6); use these functions (declared below) for
1597 * errors in the parameters or order of API function calls on read. The
1598 * 'warning' should be used for an error that can be handled completely; the
1599 * 'error' for one which can be handled safely but which may lose application
1600 * information or settings.
1602 * By default these both result in a png_error call prior to release, while in a
1603 * released version the 'warning' is just a warning. However if the application
1604 * explicitly disables benign errors (explicitly permitting the code to lose
1605 * information) they both turn into warnings.
1607 * If benign errors aren't supported they end up as the corresponding base call
1608 * (png_warning or png_error.)
1610 PNG_INTERNAL_FUNCTION(void,png_app_warning,(png_const_structrp png_ptr,
1611 png_const_charp message),PNG_EMPTY);
1612 /* The application provided invalid parameters to an API function or called
1613 * an API function at the wrong time, libpng can completely recover.
1616 PNG_INTERNAL_FUNCTION(void,png_app_error,(png_const_structrp png_ptr,
1617 png_const_charp message),PNG_EMPTY);
1618 /* As above but libpng will ignore the call, or attempt some other partial
1619 * recovery from the error.
1622 # define png_app_warning(pp,s) png_warning(pp,s)
1623 # define png_app_error(pp,s) png_error(pp,s)
1626 PNG_INTERNAL_FUNCTION(void,png_chunk_report,(png_const_structrp png_ptr,
1627 png_const_charp message, int error),PNG_EMPTY);
1628 /* Report a recoverable issue in chunk data. On read this is used to report
1629 * a problem found while reading a particular chunk and the
1630 * png_chunk_benign_error or png_chunk_warning function is used as
1631 * appropriate. On write this is used to report an error that comes from
1632 * data set via an application call to a png_set_ API and png_app_error or
1633 * png_app_warning is used as appropriate.
1635 * The 'error' parameter must have one of the following values:
1637 #define PNG_CHUNK_WARNING 0 /* never an error */
1638 #define PNG_CHUNK_WRITE_ERROR 1 /* an error only on write */
1639 #define PNG_CHUNK_ERROR 2 /* always an error */
1641 /* ASCII to FP interfaces, currently only implemented if sCAL
1642 * support is required.
1644 #if defined(PNG_sCAL_SUPPORTED)
1645 /* MAX_DIGITS is actually the maximum number of characters in an sCAL
1646 * width or height, derived from the precision (number of significant
1647 * digits - a build time settable option) and assumptions about the
1648 * maximum ridiculous exponent.
1650 #define PNG_sCAL_MAX_DIGITS (PNG_sCAL_PRECISION+1/*.*/+1/*E*/+10/*exponent*/)
1652 #ifdef PNG_FLOATING_POINT_SUPPORTED
1653 PNG_INTERNAL_FUNCTION(void,png_ascii_from_fp,(png_const_structrp png_ptr,
1654 png_charp ascii, png_size_t size, double fp, unsigned int precision),
1656 #endif /* FLOATING_POINT */
1658 #ifdef PNG_FIXED_POINT_SUPPORTED
1659 PNG_INTERNAL_FUNCTION(void,png_ascii_from_fixed,(png_const_structrp png_ptr,
1660 png_charp ascii, png_size_t size, png_fixed_point fp),PNG_EMPTY);
1661 #endif /* FIXED_POINT */
1664 #if defined(PNG_sCAL_SUPPORTED) || defined(PNG_pCAL_SUPPORTED)
1665 /* An internal API to validate the format of a floating point number.
1666 * The result is the index of the next character. If the number is
1667 * not valid it will be the index of a character in the supposed number.
1669 * The format of a number is defined in the PNG extensions specification
1670 * and this API is strictly conformant to that spec, not anyone elses!
1672 * The format as a regular expression is:
1674 * [+-]?[0-9]+.?([Ee][+-]?[0-9]+)?
1678 * [+-]?.[0-9]+(.[0-9]+)?([Ee][+-]?[0-9]+)?
1680 * The complexity is that either integer or fraction must be present and the
1681 * fraction is permitted to have no digits only if the integer is present.
1683 * NOTE: The dangling E problem.
1684 * There is a PNG valid floating point number in the following:
1686 * PNG floating point numbers are not greedy.
1688 * Working this out requires *TWO* character lookahead (because of the
1689 * sign), the parser does not do this - it will fail at the 'r' - this
1690 * doesn't matter for PNG sCAL chunk values, but it requires more care
1691 * if the value were ever to be embedded in something more complex. Use
1692 * ANSI-C strtod if you need the lookahead.
1694 /* State table for the parser. */
1695 #define PNG_FP_INTEGER 0 /* before or in integer */
1696 #define PNG_FP_FRACTION 1 /* before or in fraction */
1697 #define PNG_FP_EXPONENT 2 /* before or in exponent */
1698 #define PNG_FP_STATE 3 /* mask for the above */
1699 #define PNG_FP_SAW_SIGN 4 /* Saw +/- in current state */
1700 #define PNG_FP_SAW_DIGIT 8 /* Saw a digit in current state */
1701 #define PNG_FP_SAW_DOT 16 /* Saw a dot in current state */
1702 #define PNG_FP_SAW_E 32 /* Saw an E (or e) in current state */
1703 #define PNG_FP_SAW_ANY 60 /* Saw any of the above 4 */
1705 /* These three values don't affect the parser. They are set but not used.
1707 #define PNG_FP_WAS_VALID 64 /* Preceding substring is a valid fp number */
1708 #define PNG_FP_NEGATIVE 128 /* A negative number, including "-0" */
1709 #define PNG_FP_NONZERO 256 /* A non-zero value */
1710 #define PNG_FP_STICKY 448 /* The above three flags */
1712 /* This is available for the caller to store in 'state' if required. Do not
1713 * call the parser after setting it (the parser sometimes clears it.)
1715 #define PNG_FP_INVALID 512 /* Available for callers as a distinct value */
1717 /* Result codes for the parser (boolean - true meants ok, false means
1720 #define PNG_FP_MAYBE 0 /* The number may be valid in the future */
1721 #define PNG_FP_OK 1 /* The number is valid */
1723 /* Tests on the sticky non-zero and negative flags. To pass these checks
1724 * the state must also indicate that the whole number is valid - this is
1725 * achieved by testing PNG_FP_SAW_DIGIT (see the implementation for why this
1726 * is equivalent to PNG_FP_OK above.)
1728 #define PNG_FP_NZ_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NEGATIVE | PNG_FP_NONZERO)
1729 /* NZ_MASK: the string is valid and a non-zero negative value */
1730 #define PNG_FP_Z_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NONZERO)
1731 /* Z MASK: the string is valid and a non-zero value. */
1732 /* PNG_FP_SAW_DIGIT: the string is valid. */
1733 #define PNG_FP_IS_ZERO(state) (((state) & PNG_FP_Z_MASK) == PNG_FP_SAW_DIGIT)
1734 #define PNG_FP_IS_POSITIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_Z_MASK)
1735 #define PNG_FP_IS_NEGATIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_NZ_MASK)
1737 /* The actual parser. This can be called repeatedly. It updates
1738 * the index into the string and the state variable (which must
1739 * be initialized to 0). It returns a result code, as above. There
1740 * is no point calling the parser any more if it fails to advance to
1741 * the end of the string - it is stuck on an invalid character (or
1742 * terminated by '\0').
1744 * Note that the pointer will consume an E or even an E+ and then leave
1745 * a 'maybe' state even though a preceding integer.fraction is valid.
1746 * The PNG_FP_WAS_VALID flag indicates that a preceding substring was
1747 * a valid number. It's possible to recover from this by calling
1748 * the parser again (from the start, with state 0) but with a string
1749 * that omits the last character (i.e. set the size to the index of
1750 * the problem character.) This has not been tested within libpng.
1752 PNG_INTERNAL_FUNCTION(int,png_check_fp_number,(png_const_charp string,
1753 png_size_t size, int *statep, png_size_tp whereami),PNG_EMPTY);
1755 /* This is the same but it checks a complete string and returns true
1756 * only if it just contains a floating point number. As of 1.5.4 this
1757 * function also returns the state at the end of parsing the number if
1758 * it was valid (otherwise it returns 0.) This can be used for testing
1759 * for negative or zero values using the sticky flag.
1761 PNG_INTERNAL_FUNCTION(int,png_check_fp_string,(png_const_charp string,
1762 png_size_t size),PNG_EMPTY);
1763 #endif /* pCAL || sCAL */
1765 #if defined(PNG_READ_GAMMA_SUPPORTED) ||\
1766 defined(PNG_INCH_CONVERSIONS_SUPPORTED) || defined(PNG_READ_pHYs_SUPPORTED)
1767 /* Added at libpng version 1.5.0 */
1768 /* This is a utility to provide a*times/div (rounded) and indicate
1769 * if there is an overflow. The result is a boolean - false (0)
1770 * for overflow, true (1) if no overflow, in which case *res
1773 PNG_INTERNAL_FUNCTION(int,png_muldiv,(png_fixed_point_p res, png_fixed_point a,
1774 png_int_32 multiplied_by, png_int_32 divided_by),PNG_EMPTY);
1777 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_INCH_CONVERSIONS_SUPPORTED)
1778 /* Same deal, but issue a warning on overflow and return 0. */
1779 PNG_INTERNAL_FUNCTION(png_fixed_point,png_muldiv_warn,
1780 (png_const_structrp png_ptr, png_fixed_point a, png_int_32 multiplied_by,
1781 png_int_32 divided_by),PNG_EMPTY);
1784 #ifdef PNG_GAMMA_SUPPORTED
1785 /* Calculate a reciprocal - used for gamma values. This returns
1786 * 0 if the argument is 0 in order to maintain an undefined value;
1787 * there are no warnings.
1789 PNG_INTERNAL_FUNCTION(png_fixed_point,png_reciprocal,(png_fixed_point a),
1792 #ifdef PNG_READ_GAMMA_SUPPORTED
1793 /* The same but gives a reciprocal of the product of two fixed point
1794 * values. Accuracy is suitable for gamma calculations but this is
1795 * not exact - use png_muldiv for that. Only required at present on read.
1797 PNG_INTERNAL_FUNCTION(png_fixed_point,png_reciprocal2,(png_fixed_point a,
1798 png_fixed_point b),PNG_EMPTY);
1801 /* Return true if the gamma value is significantly different from 1.0 */
1802 PNG_INTERNAL_FUNCTION(int,png_gamma_significant,(png_fixed_point gamma_value),
1806 #ifdef PNG_READ_GAMMA_SUPPORTED
1807 /* Internal fixed point gamma correction. These APIs are called as
1808 * required to convert single values - they don't need to be fast,
1809 * they are not used when processing image pixel values.
1811 * While the input is an 'unsigned' value it must actually be the
1812 * correct bit value - 0..255 or 0..65535 as required.
1814 PNG_INTERNAL_FUNCTION(png_uint_16,png_gamma_correct,(png_structrp png_ptr,
1815 unsigned int value, png_fixed_point gamma_value),PNG_EMPTY);
1816 PNG_INTERNAL_FUNCTION(png_uint_16,png_gamma_16bit_correct,(unsigned int value,
1817 png_fixed_point gamma_value),PNG_EMPTY);
1818 PNG_INTERNAL_FUNCTION(png_byte,png_gamma_8bit_correct,(unsigned int value,
1819 png_fixed_point gamma_value),PNG_EMPTY);
1820 PNG_INTERNAL_FUNCTION(void,png_destroy_gamma_table,(png_structrp png_ptr),
1822 PNG_INTERNAL_FUNCTION(void,png_build_gamma_table,(png_structrp png_ptr,
1823 int bit_depth),PNG_EMPTY);
1826 /* SIMPLIFIED READ/WRITE SUPPORT */
1827 #if defined PNG_SIMPLIFIED_READ_SUPPORTED ||\
1828 defined PNG_SIMPLIFIED_WRITE_SUPPORTED
1829 /* The internal structure that png_image::opaque points to. */
1830 typedef struct png_control
1832 png_structp png_ptr;
1834 png_voidp error_buf; /* Always a jmp_buf at present. */
1836 png_const_bytep memory; /* Memory buffer. */
1837 png_size_t size; /* Size of the memory buffer. */
1839 unsigned int for_write :1; /* Otherwise it is a read structure */
1840 unsigned int owned_file :1; /* We own the file in io_ptr */
1843 /* Return the pointer to the jmp_buf from a png_control: necessary because C
1844 * does not reveal the type of the elements of jmp_buf.
1847 # define png_control_jmp_buf(pc) (((jmp_buf*)((pc)->error_buf))[0])
1849 # define png_control_jmp_buf(pc) ((pc)->error_buf)
1852 /* Utility to safely execute a piece of libpng code catching and logging any
1853 * errors that might occur. Returns true on success, false on failure (either
1854 * of the function or as a result of a png_error.)
1856 PNG_INTERNAL_FUNCTION(void,png_safe_error,(png_structp png_ptr,
1857 png_const_charp error_message),PNG_NORETURN);
1859 #ifdef PNG_WARNINGS_SUPPORTED
1860 PNG_INTERNAL_FUNCTION(void,png_safe_warning,(png_structp png_ptr,
1861 png_const_charp warning_message),PNG_EMPTY);
1863 # define png_safe_warning 0/*dummy argument*/
1866 PNG_INTERNAL_FUNCTION(int,png_safe_execute,(png_imagep image,
1867 int (*function)(png_voidp), png_voidp arg),PNG_EMPTY);
1869 /* Utility to log an error; this also cleans up the png_image; the function
1870 * always returns 0 (false).
1872 PNG_INTERNAL_FUNCTION(int,png_image_error,(png_imagep image,
1873 png_const_charp error_message),PNG_EMPTY);
1875 #ifndef PNG_SIMPLIFIED_READ_SUPPORTED
1876 /* png_image_free is used by the write code but not exported */
1877 PNG_INTERNAL_FUNCTION(void, png_image_free, (png_imagep image), PNG_EMPTY);
1878 #endif /* !SIMPLIFIED_READ */
1880 #endif /* SIMPLIFIED READ/WRITE */
1882 #ifdef PNG_FILTER_OPTIMIZATIONS
1883 PNG_INTERNAL_FUNCTION(void, PNG_FILTER_OPTIMIZATIONS, (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
1884 /* This is the initialization function for hardware specific optimizations,
1885 * one implementation (for ARM NEON machines) is contained in
1886 * arm/filter_neon.c. It need not be defined - the generic code will be used
1891 /* Maintainer: Put new private prototypes here ^ */
1893 #include "pngdebug.h"
1899 #endif /* PNGPRIV_H */