• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 
2 /* pngpriv.h - private declarations for use inside libpng
3  *
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.)
8  *
9  * Last changed in libpng 1.6.3 [July 18, 2013]
10  *
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
14  */
15 
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.
23  */
24 
25 #ifndef PNGPRIV_H
26 #define PNGPRIV_H
27 
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.
31  *
32  * Feature Test Macros must be defined before any system header is included (see
33  * POSIX 1003.1 2.8.2 "POSIX Symbols."
34  *
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.)
39  */
40 #define _POSIX_SOURCE 1 /* Just the POSIX 1003.1 and C89 APIs */
41 
42 #ifndef PNG_VERSION_INFO_ONLY
43 /* Standard library headers not required by png.h: */
44 #  include <stdlib.h>
45 #  include <string.h>
46 #endif
47 
48 #define PNGLIB_BUILD /*libpng is being built, not used*/
49 
50 /* If HAVE_CONFIG_H is defined during the build then the build system must
51  * provide an appropriate "config.h" file on the include path.  The header file
52  * must provide definitions as required below (search for "HAVE_CONFIG_H");
53  * see configure.ac for more details of the requirements.  The macro
54  * "PNG_NO_CONFIG_H" is provided for maintainers to test for dependencies on
55  * 'configure'; define this macro to prevent the configure build including the
56  * configure generated config.h.  Libpng is expected to compile without *any*
57  * special build system support on a reasonably ANSI-C compliant system.
58  */
59 #if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
60 #  include <config.h>
61 
62    /* Pick up the definition of 'restrict' from config.h if it was read: */
63 #  define PNG_RESTRICT restrict
64 #endif
65 
66 /* To support symbol prefixing it is necessary to know *before* including png.h
67  * whether the fixed point (and maybe other) APIs are exported, because if they
68  * are not internal definitions may be required.  This is handled below just
69  * before png.h is included, but load the configuration now if it is available.
70  */
71 #ifndef PNGLCONF_H
72 #  include "pnglibconf.h"
73 #endif
74 
75 /* Local renames may change non-exported API functions from png.h */
76 #if defined(PNG_PREFIX) && !defined(PNGPREFIX_H)
77 #  include "pngprefix.h"
78 #endif
79 
80 #ifdef PNG_USER_CONFIG
81 #  include "pngusr.h"
82    /* These should have been defined in pngusr.h */
83 #  ifndef PNG_USER_PRIVATEBUILD
84 #    define PNG_USER_PRIVATEBUILD "Custom libpng build"
85 #  endif
86 #  ifndef PNG_USER_DLLFNAME_POSTFIX
87 #    define PNG_USER_DLLFNAME_POSTFIX "Cb"
88 #  endif
89 #endif
90 
91 /* Compile time options.
92  * =====================
93  * In a multi-arch build the compiler may compile the code several times for the
94  * same object module, producing different binaries for different architectures.
95  * When this happens configure-time setting of the target host options cannot be
96  * done and this interferes with the handling of the ARM NEON optimizations, and
97  * possibly other similar optimizations.  Put additional tests here; in general
98  * this is needed when the same option can be changed at both compile time and
99  * run time depending on the target OS (i.e. iOS vs Android.)
100  *
101  * NOTE: symbol prefixing does not pass $(CFLAGS) to the preprocessor, because
102  * this is not possible with certain compilers (Oracle SUN OS CC), as a result
103  * it is necessary to ensure that all extern functions that *might* be used
104  * regardless of $(CFLAGS) get declared in this file.  The test on __ARM_NEON__
105  * below is one example of this behavior because it is controlled by the
106  * presence or not of -mfpu=neon on the GCC command line, it is possible to do
107  * this in $(CC), e.g. "CC=gcc -mfpu=neon", but people who build libpng rarely
108  * do this.
109  */
110 #ifndef PNG_ARM_NEON_OPT
111    /* ARM NEON optimizations are being controlled by the compiler settings,
112     * typically the target FPU.  If the FPU has been set to NEON (-mfpu=neon
113     * with GCC) then the compiler will define __ARM_NEON__ and we can rely
114     * unconditionally on NEON instructions not crashing, otherwise we must
115     * disable use of NEON instructions:
116     */
117 #  ifdef __ARM_NEON__
118 #     define PNG_ARM_NEON_OPT 2
119 #  else
120 #     define PNG_ARM_NEON_OPT 0
121 #  endif
122 #endif
123 
124 #if PNG_ARM_NEON_OPT > 0
125    /* NEON optimizations are to be at least considered by libpng, so enable the
126     * callbacks to do this.
127     */
128 #  define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_neon
129 #endif
130 
131 /* Is this a build of a DLL where compilation of the object modules requires
132  * different preprocessor settings to those required for a simple library?  If
133  * so PNG_BUILD_DLL must be set.
134  *
135  * If libpng is used inside a DLL but that DLL does not export the libpng APIs
136  * PNG_BUILD_DLL must not be set.  To avoid the code below kicking in build a
137  * static library of libpng then link the DLL against that.
138  */
139 #ifndef PNG_BUILD_DLL
140 #  ifdef DLL_EXPORT
141       /* This is set by libtool when files are compiled for a DLL; libtool
142        * always compiles twice, even on systems where it isn't necessary.  Set
143        * PNG_BUILD_DLL in case it is necessary:
144        */
145 #     define PNG_BUILD_DLL
146 #  else
147 #     ifdef _WINDLL
148          /* This is set by the Microsoft Visual Studio IDE in projects that
149           * build a DLL.  It can't easily be removed from those projects (it
150           * isn't visible in the Visual Studio UI) so it is a fairly reliable
151           * indication that PNG_IMPEXP needs to be set to the DLL export
152           * attributes.
153           */
154 #        define PNG_BUILD_DLL
155 #     else
156 #        ifdef __DLL__
157             /* This is set by the Borland C system when compiling for a DLL
158              * (as above.)
159              */
160 #           define PNG_BUILD_DLL
161 #        else
162             /* Add additional compiler cases here. */
163 #        endif
164 #     endif
165 #  endif
166 #endif /* Setting PNG_BUILD_DLL if required */
167 
168 /* See pngconf.h for more details: the builder of the library may set this on
169  * the command line to the right thing for the specific compilation system or it
170  * may be automagically set above (at present we know of no system where it does
171  * need to be set on the command line.)
172  *
173  * PNG_IMPEXP must be set here when building the library to prevent pngconf.h
174  * setting it to the "import" setting for a DLL build.
175  */
176 #ifndef PNG_IMPEXP
177 #  ifdef PNG_BUILD_DLL
178 #     define PNG_IMPEXP PNG_DLL_EXPORT
179 #  else
180       /* Not building a DLL, or the DLL doesn't require specific export
181        * definitions.
182        */
183 #     define PNG_IMPEXP
184 #  endif
185 #endif
186 
187 /* No warnings for private or deprecated functions in the build: */
188 #ifndef PNG_DEPRECATED
189 #  define PNG_DEPRECATED
190 #endif
191 #ifndef PNG_PRIVATE
192 #  define PNG_PRIVATE
193 #endif
194 
195 /* Symbol preprocessing support.
196  *
197  * To enable listing global, but internal, symbols the following macros should
198  * always be used to declare an extern data or function object in this file.
199  */
200 #ifndef PNG_INTERNAL_DATA
201 #  define PNG_INTERNAL_DATA(type, name, array) extern type name array
202 #endif
203 
204 #ifndef PNG_INTERNAL_FUNCTION
205 #  define PNG_INTERNAL_FUNCTION(type, name, args, attributes)\
206       extern PNG_FUNCTION(type, name, args, PNG_EMPTY attributes)
207 #endif
208 
209 /* If floating or fixed point APIs are disabled they may still be compiled
210  * internally.  To handle this make sure they are declared as the appropriate
211  * internal extern function (otherwise the symbol prefixing stuff won't work and
212  * the functions will be used without definitions.)
213  *
214  * NOTE: although all the API functions are declared here they are not all
215  * actually built!  Because the declarations are still made it is necessary to
216  * fake out types that they depend on.
217  */
218 #ifndef PNG_FP_EXPORT
219 #  ifndef PNG_FLOATING_POINT_SUPPORTED
220 #     define PNG_FP_EXPORT(ordinal, type, name, args)\
221          PNG_INTERNAL_FUNCTION(type, name, args, PNG_EMPTY);
222 #     ifndef PNG_VERSION_INFO_ONLY
223          typedef struct png_incomplete png_double;
224          typedef png_double*           png_doublep;
225          typedef const png_double*     png_const_doublep;
226          typedef png_double**          png_doublepp;
227 #     endif
228 #  endif
229 #endif
230 #ifndef PNG_FIXED_EXPORT
231 #  ifndef PNG_FIXED_POINT_SUPPORTED
232 #     define PNG_FIXED_EXPORT(ordinal, type, name, args)\
233          PNG_INTERNAL_FUNCTION(type, name, args, PNG_EMPTY);
234 #  endif
235 #endif
236 
237 #include "png.h"
238 
239 /* pngconf.h does not set PNG_DLL_EXPORT unless it is required, so: */
240 #ifndef PNG_DLL_EXPORT
241 #  define PNG_DLL_EXPORT
242 #endif
243 
244 /* SECURITY and SAFETY:
245  *
246  * By default libpng is built without any internal limits on image size,
247  * individual heap (png_malloc) allocations or the total amount of memory used.
248  * If PNG_SAFE_LIMITS_SUPPORTED is defined, however, the limits below are used
249  * (unless individually overridden).  These limits are believed to be fairly
250  * safe, but builders of secure systems should verify the values against the
251  * real system capabilities.
252  */
253 #ifdef PNG_SAFE_LIMITS_SUPPORTED
254    /* 'safe' limits */
255 #  ifndef PNG_USER_WIDTH_MAX
256 #     define PNG_USER_WIDTH_MAX 1000000
257 #  endif
258 #  ifndef PNG_USER_HEIGHT_MAX
259 #     define PNG_USER_HEIGHT_MAX 1000000
260 #  endif
261 #  ifndef PNG_USER_CHUNK_CACHE_MAX
262 #     define PNG_USER_CHUNK_CACHE_MAX 128
263 #  endif
264 #  ifndef PNG_USER_CHUNK_MALLOC_MAX
265 #     define PNG_USER_CHUNK_MALLOC_MAX 8000000
266 #  endif
267 #else
268    /* values for no limits */
269 #  ifndef PNG_USER_WIDTH_MAX
270 #     define PNG_USER_WIDTH_MAX 0x7fffffff
271 #  endif
272 #  ifndef PNG_USER_HEIGHT_MAX
273 #     define PNG_USER_HEIGHT_MAX 0x7fffffff
274 #  endif
275 #  ifndef PNG_USER_CHUNK_CACHE_MAX
276 #     define PNG_USER_CHUNK_CACHE_MAX 0
277 #  endif
278 #  ifndef PNG_USER_CHUNK_MALLOC_MAX
279 #     define PNG_USER_CHUNK_MALLOC_MAX 0
280 #  endif
281 #endif
282 
283 /* Moved to pngpriv.h at libpng-1.5.0 */
284 /* NOTE: some of these may have been used in external applications as
285  * these definitions were exposed in pngconf.h prior to 1.5.
286  */
287 
288 /* If you are running on a machine where you cannot allocate more
289  * than 64K of memory at once, uncomment this.  While libpng will not
290  * normally need that much memory in a chunk (unless you load up a very
291  * large file), zlib needs to know how big of a chunk it can use, and
292  * libpng thus makes sure to check any memory allocation to verify it
293  * will fit into memory.
294  *
295  * zlib provides 'MAXSEG_64K' which, if defined, indicates the
296  * same limit and pngconf.h (already included) sets the limit
297  * if certain operating systems are detected.
298  */
299 #if defined(MAXSEG_64K) && !defined(PNG_MAX_MALLOC_64K)
300 #  define PNG_MAX_MALLOC_64K
301 #endif
302 
303 #ifndef PNG_UNUSED
304 /* Unused formal parameter warnings are silenced using the following macro
305  * which is expected to have no bad effects on performance (optimizing
306  * compilers will probably remove it entirely).  Note that if you replace
307  * it with something other than whitespace, you must include the terminating
308  * semicolon.
309  */
310 #  define PNG_UNUSED(param) (void)param;
311 #endif
312 
313 /* Just a little check that someone hasn't tried to define something
314  * contradictory.
315  */
316 #if (PNG_ZBUF_SIZE > 65536L) && defined(PNG_MAX_MALLOC_64K)
317 #  undef PNG_ZBUF_SIZE
318 #  define PNG_ZBUF_SIZE 65536L
319 #endif
320 
321 /* If warnings or errors are turned off the code is disabled or redirected here.
322  * From 1.5.4 functions have been added to allow very limited formatting of
323  * error and warning messages - this code will also be disabled here.
324  */
325 #ifdef PNG_WARNINGS_SUPPORTED
326 #  define PNG_WARNING_PARAMETERS(p) png_warning_parameters p;
327 #else
328 #  define png_warning(s1,s2) ((void)(s1))
329 #  define png_chunk_warning(s1,s2) ((void)(s1))
330 #  define png_warning_parameter(p,number,string) ((void)0)
331 #  define png_warning_parameter_unsigned(p,number,format,value) ((void)0)
332 #  define png_warning_parameter_signed(p,number,format,value) ((void)0)
333 #  define png_formatted_warning(pp,p,message) ((void)(pp))
334 #  define PNG_WARNING_PARAMETERS(p)
335 #endif
336 #ifndef PNG_ERROR_TEXT_SUPPORTED
337 #  define png_error(s1,s2) png_err(s1)
338 #  define png_chunk_error(s1,s2) png_err(s1)
339 #  define png_fixed_error(s1,s2) png_err(s1)
340 #endif
341 
342 /* C allows up-casts from (void*) to any pointer and (const void*) to any
343  * pointer to a const object.  C++ regards this as a type error and requires an
344  * explicit, static, cast and provides the static_cast<> rune to ensure that
345  * const is not cast away.
346  */
347 #ifdef __cplusplus
348 #  define png_voidcast(type, value) static_cast<type>(value)
349 #  define png_constcast(type, value) const_cast<type>(value)
350 #  define png_aligncast(type, value) \
351    static_cast<type>(static_cast<void*>(value))
352 #  define png_aligncastconst(type, value) \
353    static_cast<type>(static_cast<const void*>(value))
354 #else
355 #  define png_voidcast(type, value) (value)
356 #  define png_constcast(type, value) ((type)(value))
357 #  define png_aligncast(type, value) ((void*)(value))
358 #  define png_aligncastconst(type, value) ((const void*)(value))
359 #endif /* __cplusplus */
360 
361 /* Some fixed point APIs are still required even if not exported because
362  * they get used by the corresponding floating point APIs.  This magic
363  * deals with this:
364  */
365 #ifdef PNG_FIXED_POINT_SUPPORTED
366 #  define PNGFAPI PNGAPI
367 #else
368 #  define PNGFAPI /* PRIVATE */
369 #endif
370 
371 #ifndef PNG_VERSION_INFO_ONLY
372 /* Other defines specific to compilers can go here.  Try to keep
373  * them inside an appropriate ifdef/endif pair for portability.
374  */
375 #if defined(PNG_FLOATING_POINT_SUPPORTED) ||\
376     defined(PNG_FLOATING_ARITHMETIC_SUPPORTED)
377    /* png.c requires the following ANSI-C constants if the conversion of
378     * floating point to ASCII is implemented therein:
379     *
380     *  DBL_DIG  Maximum number of decimal digits (can be set to any constant)
381     *  DBL_MIN  Smallest normalized fp number (can be set to an arbitrary value)
382     *  DBL_MAX  Maximum floating point number (can be set to an arbitrary value)
383     */
384 #  include <float.h>
385 
386 #  if (defined(__MWERKS__) && defined(macintosh)) || defined(applec) || \
387     defined(THINK_C) || defined(__SC__) || defined(TARGET_OS_MAC)
388      /* We need to check that <math.h> hasn't already been included earlier
389       * as it seems it doesn't agree with <fp.h>, yet we should really use
390       * <fp.h> if possible.
391       */
392 #    if !defined(__MATH_H__) && !defined(__MATH_H) && !defined(__cmath__)
393 #      include <fp.h>
394 #    endif
395 #  else
396 #    include <math.h>
397 #  endif
398 #  if defined(_AMIGA) && defined(__SASC) && defined(_M68881)
399      /* Amiga SAS/C: We must include builtin FPU functions when compiling using
400       * MATH=68881
401       */
402 #    include <m68881.h>
403 #  endif
404 #endif
405 
406 /* This provides the non-ANSI (far) memory allocation routines. */
407 #if defined(__TURBOC__) && defined(__MSDOS__)
408 #  include <mem.h>
409 #  include <alloc.h>
410 #endif
411 
412 #if defined(WIN32) || defined(_Windows) || defined(_WINDOWS) || \
413     defined(_WIN32) || defined(__WIN32__)
414 #  include <windows.h>  /* defines _WINDOWS_ macro */
415 #endif
416 #endif /* PNG_VERSION_INFO_ONLY */
417 
418 /* Moved here around 1.5.0beta36 from pngconf.h */
419 /* Users may want to use these so they are not private.  Any library
420  * functions that are passed far data must be model-independent.
421  */
422 
423 /* Memory model/platform independent fns */
424 #ifndef PNG_ABORT
425 #  ifdef _WINDOWS_
426 #    define PNG_ABORT() ExitProcess(0)
427 #  else
428 #    define PNG_ABORT() abort()
429 #  endif
430 #endif
431 
432 /* These macros may need to be architecture dependent. */
433 #define PNG_ALIGN_NONE   0 /* do not use data alignment */
434 #define PNG_ALIGN_ALWAYS 1 /* assume unaligned accesses are OK */
435 #ifdef offsetof
436 #  define PNG_ALIGN_OFFSET 2 /* use offsetof to determine alignment */
437 #else
438 #  define PNG_ALIGN_OFFSET -1 /* prevent the use of this */
439 #endif
440 #define PNG_ALIGN_SIZE   3 /* use sizeof to determine alignment */
441 
442 #ifndef PNG_ALIGN_TYPE
443    /* Default to using aligned access optimizations and requiring alignment to a
444     * multiple of the data type size.  Override in a compiler specific fashion
445     * if necessary by inserting tests here:
446     */
447 #  define PNG_ALIGN_TYPE PNG_ALIGN_SIZE
448 #endif
449 
450 #if PNG_ALIGN_TYPE == PNG_ALIGN_SIZE
451    /* This is used because in some compiler implementations non-aligned
452     * structure members are supported, so the offsetof approach below fails.
453     * Set PNG_ALIGN_SIZE=0 for compiler combinations where unaligned access
454     * is good for performance.  Do not do this unless you have tested the result
455     * and understand it.
456     */
457 #  define png_alignof(type) (sizeof (type))
458 #else
459 #  if PNG_ALIGN_TYPE == PNG_ALIGN_OFFSET
460 #     define png_alignof(type) offsetof(struct{char c; type t;}, t)
461 #  else
462 #     if PNG_ALIGN_TYPE == PNG_ALIGN_ALWAYS
463 #        define png_alignof(type) (1)
464 #     endif
465       /* Else leave png_alignof undefined to prevent use thereof */
466 #  endif
467 #endif
468 
469 /* This implicitly assumes alignment is always to a power of 2. */
470 #ifdef png_alignof
471 #  define png_isaligned(ptr, type)\
472    ((((const char*)ptr-(const char*)0) & (png_alignof(type)-1)) == 0)
473 #else
474 #  define png_isaligned(ptr, type) 0
475 #endif
476 
477 /* End of memory model/platform independent support */
478 /* End of 1.5.0beta36 move from pngconf.h */
479 
480 /* CONSTANTS and UTILITY MACROS
481  * These are used internally by libpng and not exposed in the API
482  */
483 
484 /* Various modes of operation.  Note that after an init, mode is set to
485  * zero automatically when the structure is created.  Three of these
486  * are defined in png.h because they need to be visible to applications
487  * that call png_set_unknown_chunk().
488  */
489 /* #define PNG_HAVE_IHDR            0x01 (defined in png.h) */
490 /* #define PNG_HAVE_PLTE            0x02 (defined in png.h) */
491 #define PNG_HAVE_IDAT               0x04
492 /* #define PNG_AFTER_IDAT           0x08 (defined in png.h) */
493 #define PNG_HAVE_IEND               0x10
494                    /*               0x20 (unused) */
495                    /*               0x40 (unused) */
496                    /*               0x80 (unused) */
497 #define PNG_HAVE_CHUNK_HEADER      0x100
498 #define PNG_WROTE_tIME             0x200
499 #define PNG_WROTE_INFO_BEFORE_PLTE 0x400
500 #define PNG_BACKGROUND_IS_GRAY     0x800
501 #define PNG_HAVE_PNG_SIGNATURE    0x1000
502 #define PNG_HAVE_CHUNK_AFTER_IDAT 0x2000 /* Have another chunk after IDAT */
503                    /*             0x4000 (unused) */
504 #define PNG_IS_READ_STRUCT        0x8000 /* Else is a write struct */
505 
506 /* Flags for the transformations the PNG library does on the image data */
507 #define PNG_BGR                 0x0001
508 #define PNG_INTERLACE           0x0002
509 #define PNG_PACK                0x0004
510 #define PNG_SHIFT               0x0008
511 #define PNG_SWAP_BYTES          0x0010
512 #define PNG_INVERT_MONO         0x0020
513 #define PNG_QUANTIZE            0x0040
514 #define PNG_COMPOSE             0x0080     /* Was PNG_BACKGROUND */
515 #define PNG_BACKGROUND_EXPAND   0x0100
516 #define PNG_EXPAND_16           0x0200     /* Added to libpng 1.5.2 */
517 #define PNG_16_TO_8             0x0400     /* Becomes 'chop' in 1.5.4 */
518 #define PNG_RGBA                0x0800
519 #define PNG_EXPAND              0x1000
520 #define PNG_GAMMA               0x2000
521 #define PNG_GRAY_TO_RGB         0x4000
522 #define PNG_FILLER              0x8000
523 #define PNG_PACKSWAP           0x10000
524 #define PNG_SWAP_ALPHA         0x20000
525 #define PNG_STRIP_ALPHA        0x40000
526 #define PNG_INVERT_ALPHA       0x80000
527 #define PNG_USER_TRANSFORM    0x100000
528 #define PNG_RGB_TO_GRAY_ERR   0x200000
529 #define PNG_RGB_TO_GRAY_WARN  0x400000
530 #define PNG_RGB_TO_GRAY       0x600000 /* two bits, RGB_TO_GRAY_ERR|WARN */
531 #define PNG_ENCODE_ALPHA      0x800000 /* Added to libpng-1.5.4 */
532 #define PNG_ADD_ALPHA         0x1000000 /* Added to libpng-1.2.7 */
533 #define PNG_EXPAND_tRNS       0x2000000 /* Added to libpng-1.2.9 */
534 #define PNG_SCALE_16_TO_8     0x4000000 /* Added to libpng-1.5.4 */
535                        /*   0x8000000 unused */
536                        /*  0x10000000 unused */
537                        /*  0x20000000 unused */
538                        /*  0x40000000 unused */
539 /* Flags for png_create_struct */
540 #define PNG_STRUCT_PNG   0x0001
541 #define PNG_STRUCT_INFO  0x0002
542 
543 /* Scaling factor for filter heuristic weighting calculations */
544 #define PNG_WEIGHT_FACTOR (1<<(PNG_WEIGHT_SHIFT))
545 #define PNG_COST_FACTOR (1<<(PNG_COST_SHIFT))
546 
547 /* Flags for the png_ptr->flags rather than declaring a byte for each one */
548 #define PNG_FLAG_ZLIB_CUSTOM_STRATEGY     0x0001
549 #define PNG_FLAG_ZSTREAM_INITIALIZED      0x0002 /* Added to libpng-1.6.0 */
550                                   /*      0x0004    unused */
551 #define PNG_FLAG_ZSTREAM_ENDED            0x0008 /* Added to libpng-1.6.0 */
552                                   /*      0x0010    unused */
553                                   /*      0x0020    unused */
554 #define PNG_FLAG_ROW_INIT                 0x0040
555 #define PNG_FLAG_FILLER_AFTER             0x0080
556 #define PNG_FLAG_CRC_ANCILLARY_USE        0x0100
557 #define PNG_FLAG_CRC_ANCILLARY_NOWARN     0x0200
558 #define PNG_FLAG_CRC_CRITICAL_USE         0x0400
559 #define PNG_FLAG_CRC_CRITICAL_IGNORE      0x0800
560 #define PNG_FLAG_ASSUME_sRGB              0x1000 /* Added to libpng-1.5.4 */
561 #define PNG_FLAG_OPTIMIZE_ALPHA           0x2000 /* Added to libpng-1.5.4 */
562 #define PNG_FLAG_DETECT_UNINITIALIZED     0x4000 /* Added to libpng-1.5.4 */
563 /* #define PNG_FLAG_KEEP_UNKNOWN_CHUNKS      0x8000 */
564 /* #define PNG_FLAG_KEEP_UNSAFE_CHUNKS      0x10000 */
565 #define PNG_FLAG_LIBRARY_MISMATCH        0x20000
566 #define PNG_FLAG_STRIP_ERROR_NUMBERS     0x40000
567 #define PNG_FLAG_STRIP_ERROR_TEXT        0x80000
568 #define PNG_FLAG_BENIGN_ERRORS_WARN     0x100000 /* Added to libpng-1.4.0 */
569 #define PNG_FLAG_APP_WARNINGS_WARN      0x200000 /* Added to libpng-1.6.0 */
570 #define PNG_FLAG_APP_ERRORS_WARN        0x400000 /* Added to libpng-1.6.0 */
571                                   /*    0x800000    unused */
572                                   /*   0x1000000    unused */
573                                   /*   0x2000000    unused */
574                                   /*   0x4000000    unused */
575                                   /*   0x8000000    unused */
576                                   /*  0x10000000    unused */
577                                   /*  0x20000000    unused */
578                                   /*  0x40000000    unused */
579 
580 #define PNG_FLAG_CRC_ANCILLARY_MASK (PNG_FLAG_CRC_ANCILLARY_USE | \
581                                      PNG_FLAG_CRC_ANCILLARY_NOWARN)
582 
583 #define PNG_FLAG_CRC_CRITICAL_MASK  (PNG_FLAG_CRC_CRITICAL_USE | \
584                                      PNG_FLAG_CRC_CRITICAL_IGNORE)
585 
586 #define PNG_FLAG_CRC_MASK           (PNG_FLAG_CRC_ANCILLARY_MASK | \
587                                      PNG_FLAG_CRC_CRITICAL_MASK)
588 
589 /* Save typing and make code easier to understand */
590 
591 #define PNG_COLOR_DIST(c1, c2) (abs((int)((c1).red) - (int)((c2).red)) + \
592    abs((int)((c1).green) - (int)((c2).green)) + \
593    abs((int)((c1).blue) - (int)((c2).blue)))
594 
595 /* Added to libpng-1.6.0: scale a 16-bit value in the range 0..65535 to 0..255
596  * by dividing by 257 *with rounding*.  This macro is exact for the given range.
597  * See the discourse in pngrtran.c png_do_scale_16_to_8.  The values in the
598  * macro were established by experiment (modifying the added value).  The macro
599  * has a second variant that takes a value already scaled by 255 and divides by
600  * 65535 - this has a maximum error of .502.  Over the range 0..65535*65535 it
601  * only gives off-by-one errors and only for 0.5% (1 in 200) of the values.
602  */
603 #define PNG_DIV65535(v24) (((v24) + 32895) >> 16)
604 #define PNG_DIV257(v16) PNG_DIV65535((png_uint_32)(v16) * 255)
605 
606 /* Added to libpng-1.2.6 JB */
607 #define PNG_ROWBYTES(pixel_bits, width) \
608     ((pixel_bits) >= 8 ? \
609     ((png_size_t)(width) * (((png_size_t)(pixel_bits)) >> 3)) : \
610     (( ((png_size_t)(width) * ((png_size_t)(pixel_bits))) + 7) >> 3) )
611 
612 /* PNG_OUT_OF_RANGE returns true if value is outside the range
613  * ideal-delta..ideal+delta.  Each argument is evaluated twice.
614  * "ideal" and "delta" should be constants, normally simple
615  * integers, "value" a variable. Added to libpng-1.2.6 JB
616  */
617 #define PNG_OUT_OF_RANGE(value, ideal, delta) \
618    ( (value) < (ideal)-(delta) || (value) > (ideal)+(delta) )
619 
620 /* Conversions between fixed and floating point, only defined if
621  * required (to make sure the code doesn't accidentally use float
622  * when it is supposedly disabled.)
623  */
624 #ifdef PNG_FLOATING_POINT_SUPPORTED
625 /* The floating point conversion can't overflow, though it can and
626  * does lose accuracy relative to the original fixed point value.
627  * In practice this doesn't matter because png_fixed_point only
628  * stores numbers with very low precision.  The png_ptr and s
629  * arguments are unused by default but are there in case error
630  * checking becomes a requirement.
631  */
632 #define png_float(png_ptr, fixed, s) (.00001 * (fixed))
633 
634 /* The fixed point conversion performs range checking and evaluates
635  * its argument multiple times, so must be used with care.  The
636  * range checking uses the PNG specification values for a signed
637  * 32 bit fixed point value except that the values are deliberately
638  * rounded-to-zero to an integral value - 21474 (21474.83 is roughly
639  * (2^31-1) * 100000). 's' is a string that describes the value being
640  * converted.
641  *
642  * NOTE: this macro will raise a png_error if the range check fails,
643  * therefore it is normally only appropriate to use this on values
644  * that come from API calls or other sources where an out of range
645  * error indicates a programming error, not a data error!
646  *
647  * NOTE: by default this is off - the macro is not used - because the
648  * function call saves a lot of code.
649  */
650 #ifdef PNG_FIXED_POINT_MACRO_SUPPORTED
651 #define png_fixed(png_ptr, fp, s) ((fp) <= 21474 && (fp) >= -21474 ?\
652     ((png_fixed_point)(100000 * (fp))) : (png_fixed_error(png_ptr, s),0))
653 #endif
654 /* else the corresponding function is defined below, inside the scope of the
655  * cplusplus test.
656  */
657 #endif
658 
659 /* Constants for known chunk types.  If you need to add a chunk, define the name
660  * here.  For historical reasons these constants have the form png_<name>; i.e.
661  * the prefix is lower case.  Please use decimal values as the parameters to
662  * match the ISO PNG specification and to avoid relying on the C locale
663  * interpretation of character values.
664  *
665  * Prior to 1.5.6 these constants were strings, as of 1.5.6 png_uint_32 values
666  * are computed and a new macro (PNG_STRING_FROM_CHUNK) added to allow a string
667  * to be generated if required.
668  *
669  * PNG_32b correctly produces a value shifted by up to 24 bits, even on
670  * architectures where (int) is only 16 bits.
671  */
672 #define PNG_32b(b,s) ((png_uint_32)(b) << (s))
673 #define PNG_U32(b1,b2,b3,b4) \
674    (PNG_32b(b1,24) | PNG_32b(b2,16) | PNG_32b(b3,8) | PNG_32b(b4,0))
675 
676 /* Constants for known chunk types.
677  *
678  * MAINTAINERS: If you need to add a chunk, define the name here.
679  * For historical reasons these constants have the form png_<name>; i.e.
680  * the prefix is lower case.  Please use decimal values as the parameters to
681  * match the ISO PNG specification and to avoid relying on the C locale
682  * interpretation of character values.  Please keep the list sorted.
683  *
684  * Notice that PNG_U32 is used to define a 32-bit value for the 4 byte chunk
685  * type.  In fact the specification does not express chunk types this way,
686  * however using a 32-bit value means that the chunk type can be read from the
687  * stream using exactly the same code as used for a 32-bit unsigned value and
688  * can be examined far more efficiently (using one arithmetic compare).
689  *
690  * Prior to 1.5.6 the chunk type constants were expressed as C strings.  The
691  * libpng API still uses strings for 'unknown' chunks and a macro,
692  * PNG_STRING_FROM_CHUNK, allows a string to be generated if required.  Notice
693  * that for portable code numeric values must still be used; the string "IHDR"
694  * is not portable and neither is PNG_U32('I', 'H', 'D', 'R').
695  *
696  * In 1.7.0 the definitions will be made public in png.h to avoid having to
697  * duplicate the same definitions in application code.
698  */
699 #define png_IDAT PNG_U32( 73,  68,  65,  84)
700 #define png_IEND PNG_U32( 73,  69,  78,  68)
701 #define png_IHDR PNG_U32( 73,  72,  68,  82)
702 #define png_PLTE PNG_U32( 80,  76,  84,  69)
703 #define png_bKGD PNG_U32( 98,  75,  71,  68)
704 #define png_cHRM PNG_U32( 99,  72,  82,  77)
705 #define png_fRAc PNG_U32(102,  82,  65,  99) /* registered, not defined */
706 #define png_gAMA PNG_U32(103,  65,  77,  65)
707 #define png_gIFg PNG_U32(103,  73,  70, 103)
708 #define png_gIFt PNG_U32(103,  73,  70, 116) /* deprecated */
709 #define png_gIFx PNG_U32(103,  73,  70, 120)
710 #define png_hIST PNG_U32(104,  73,  83,  84)
711 #define png_iCCP PNG_U32(105,  67,  67,  80)
712 #define png_iTXt PNG_U32(105,  84,  88, 116)
713 #define png_oFFs PNG_U32(111,  70,  70, 115)
714 #define png_pCAL PNG_U32(112,  67,  65,  76)
715 #define png_pHYs PNG_U32(112,  72,  89, 115)
716 #define png_sBIT PNG_U32(115,  66,  73,  84)
717 #define png_sCAL PNG_U32(115,  67,  65,  76)
718 #define png_sPLT PNG_U32(115,  80,  76,  84)
719 #define png_sRGB PNG_U32(115,  82,  71,  66)
720 #define png_sTER PNG_U32(115,  84,  69,  82)
721 #define png_tEXt PNG_U32(116,  69,  88, 116)
722 #define png_tIME PNG_U32(116,  73,  77,  69)
723 #define png_tRNS PNG_U32(116,  82,  78,  83)
724 #define png_zTXt PNG_U32(122,  84,  88, 116)
725 
726 /* The following will work on (signed char*) strings, whereas the get_uint_32
727  * macro will fail on top-bit-set values because of the sign extension.
728  */
729 #define PNG_CHUNK_FROM_STRING(s)\
730    PNG_U32(0xff&(s)[0], 0xff&(s)[1], 0xff&(s)[2], 0xff&(s)[3])
731 
732 /* This uses (char), not (png_byte) to avoid warnings on systems where (char) is
733  * signed and the argument is a (char[])  This macro will fail miserably on
734  * systems where (char) is more than 8 bits.
735  */
736 #define PNG_STRING_FROM_CHUNK(s,c)\
737    (void)(((char*)(s))[0]=(char)((c)>>24), ((char*)(s))[1]=(char)((c)>>16),\
738    ((char*)(s))[2]=(char)((c)>>8), ((char*)(s))[3]=(char)((c)))
739 
740 /* Do the same but terminate with a null character. */
741 #define PNG_CSTRING_FROM_CHUNK(s,c)\
742    (void)(PNG_STRING_FROM_CHUNK(s,c), ((char*)(s))[4] = 0)
743 
744 /* Test on flag values as defined in the spec (section 5.4): */
745 #define PNG_CHUNK_ANCILLARY(c)   (1 & ((c) >> 29))
746 #define PNG_CHUNK_CRITICAL(c)     (!PNG_CHUNK_ANCILLARY(c))
747 #define PNG_CHUNK_PRIVATE(c)      (1 & ((c) >> 21))
748 #define PNG_CHUNK_RESERVED(c)     (1 & ((c) >> 13))
749 #define PNG_CHUNK_SAFE_TO_COPY(c) (1 & ((c) >>  5))
750 
751 /* Gamma values (new at libpng-1.5.4): */
752 #define PNG_GAMMA_MAC_OLD 151724  /* Assume '1.8' is really 2.2/1.45! */
753 #define PNG_GAMMA_MAC_INVERSE 65909
754 #define PNG_GAMMA_sRGB_INVERSE 45455
755 
756 /* Almost everything below is C specific; the #defines above can be used in
757  * non-C code (so long as it is C-preprocessed) the rest of this stuff cannot.
758  */
759 #ifndef PNG_VERSION_INFO_ONLY
760 
761 #include "pngstruct.h"
762 #include "pnginfo.h"
763 
764 /* Validate the include paths - the include path used to generate pnglibconf.h
765  * must match that used in the build, or we must be using pnglibconf.h.prebuilt:
766  */
767 #if PNG_ZLIB_VERNUM != 0 && PNG_ZLIB_VERNUM != ZLIB_VERNUM
768 #  error ZLIB_VERNUM != PNG_ZLIB_VERNUM \
769       "-I (include path) error: see the notes in pngpriv.h"
770    /* This means that when pnglibconf.h was built the copy of zlib.h that it
771     * used is not the same as the one being used here.  Because the build of
772     * libpng makes decisions to use inflateInit2 and inflateReset2 based on the
773     * zlib version number and because this affects handling of certain broken
774     * PNG files the -I directives must match.
775     *
776     * The most likely explanation is that you passed a -I in CFLAGS, this will
777     * not work; all the preprocessor directories and in particular all the -I
778     * directives must be in CPPFLAGS.
779     */
780 #endif
781 
782 /* This is used for 16 bit gamma tables -- only the top level pointers are
783  * const; this could be changed:
784  */
785 typedef const png_uint_16p * png_const_uint_16pp;
786 
787 /* Added to libpng-1.5.7: sRGB conversion tables */
788 #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
789    defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
790 #ifdef PNG_SIMPLIFIED_READ_SUPPORTED
791 PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_table, [256]);
792    /* Convert from an sRGB encoded value 0..255 to a 16-bit linear value,
793     * 0..65535.  This table gives the closest 16-bit answers (no errors).
794     */
795 #endif
796 
797 PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_base, [512]);
798 PNG_INTERNAL_DATA(const png_byte, png_sRGB_delta, [512]);
799 
800 #define PNG_sRGB_FROM_LINEAR(linear) ((png_byte)((png_sRGB_base[(linear)>>15] +\
801    ((((linear)&0x7fff)*png_sRGB_delta[(linear)>>15])>>12)) >> 8))
802    /* Given a value 'linear' in the range 0..255*65535 calculate the 8-bit sRGB
803     * encoded value with maximum error 0.646365.  Note that the input is not a
804     * 16-bit value; it has been multiplied by 255! */
805 #endif /* PNG_SIMPLIFIED_READ/WRITE */
806 
807 
808 /* Inhibit C++ name-mangling for libpng functions but not for system calls. */
809 #ifdef __cplusplus
810 extern "C" {
811 #endif /* __cplusplus */
812 
813 /* Internal functions; these are not exported from a DLL however because they
814  * are used within several of the C source files they have to be C extern.
815  *
816  * All of these functions must be declared with PNG_INTERNAL_FUNCTION.
817  */
818 
819 /* Zlib support */
820 #define PNG_UNEXPECTED_ZLIB_RETURN (-7)
821 PNG_INTERNAL_FUNCTION(void, png_zstream_error,(png_structrp png_ptr, int ret),
822    PNG_EMPTY);
823    /* Used by the zlib handling functions to ensure that z_stream::msg is always
824     * set before they return.
825     */
826 
827 #ifdef PNG_WRITE_SUPPORTED
828 PNG_INTERNAL_FUNCTION(void,png_free_buffer_list,(png_structrp png_ptr,
829    png_compression_bufferp *list),PNG_EMPTY);
830    /* Free the buffer list used by the compressed write code. */
831 #endif
832 
833 #if defined(PNG_FLOATING_POINT_SUPPORTED) && \
834    !defined(PNG_FIXED_POINT_MACRO_SUPPORTED) && \
835    (defined(PNG_gAMA_SUPPORTED) || defined(PNG_cHRM_SUPPORTED) || \
836    defined(PNG_sCAL_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) || \
837    defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)) || \
838    (defined(PNG_sCAL_SUPPORTED) && \
839    defined(PNG_FLOATING_ARITHMETIC_SUPPORTED))
840 PNG_INTERNAL_FUNCTION(png_fixed_point,png_fixed,(png_const_structrp png_ptr,
841    double fp, png_const_charp text),PNG_EMPTY);
842 #endif
843 
844 /* Check the user version string for compatibility, returns false if the version
845  * numbers aren't compatible.
846  */
847 PNG_INTERNAL_FUNCTION(int,png_user_version_check,(png_structrp png_ptr,
848    png_const_charp user_png_ver),PNG_EMPTY);
849 
850 /* Internal base allocator - no messages, NULL on failure to allocate.  This
851  * does, however, call the application provided allocator and that could call
852  * png_error (although that would be a bug in the application implementation.)
853  */
854 PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_base,(png_const_structrp png_ptr,
855    png_alloc_size_t size),PNG_ALLOCATED);
856 
857 #if defined(PNG_TEXT_SUPPORTED) || defined(PNG_sPLT_SUPPORTED) ||\
858    defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED)
859 /* Internal array allocator, outputs no error or warning messages on failure,
860  * just returns NULL.
861  */
862 PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_array,(png_const_structrp png_ptr,
863    int nelements, size_t element_size),PNG_ALLOCATED);
864 
865 /* The same but an existing array is extended by add_elements.  This function
866  * also memsets the new elements to 0 and copies the old elements.  The old
867  * array is not freed or altered.
868  */
869 PNG_INTERNAL_FUNCTION(png_voidp,png_realloc_array,(png_const_structrp png_ptr,
870    png_const_voidp array, int old_elements, int add_elements,
871    size_t element_size),PNG_ALLOCATED);
872 #endif /* text, sPLT or unknown chunks */
873 
874 /* Magic to create a struct when there is no struct to call the user supplied
875  * memory allocators.  Because error handling has not been set up the memory
876  * handlers can't safely call png_error, but this is an obscure and undocumented
877  * restriction so libpng has to assume that the 'free' handler, at least, might
878  * call png_error.
879  */
880 PNG_INTERNAL_FUNCTION(png_structp,png_create_png_struct,
881    (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
882     png_error_ptr warn_fn, png_voidp mem_ptr, png_malloc_ptr malloc_fn,
883     png_free_ptr free_fn),PNG_ALLOCATED);
884 
885 /* Free memory from internal libpng struct */
886 PNG_INTERNAL_FUNCTION(void,png_destroy_png_struct,(png_structrp png_ptr),
887    PNG_EMPTY);
888 
889 /* Free an allocated jmp_buf (always succeeds) */
890 PNG_INTERNAL_FUNCTION(void,png_free_jmpbuf,(png_structrp png_ptr),PNG_EMPTY);
891 
892 /* Function to allocate memory for zlib.  PNGAPI is disallowed. */
893 PNG_INTERNAL_FUNCTION(voidpf,png_zalloc,(voidpf png_ptr, uInt items, uInt size),
894    PNG_ALLOCATED);
895 
896 /* Function to free memory for zlib.  PNGAPI is disallowed. */
897 PNG_INTERNAL_FUNCTION(void,png_zfree,(voidpf png_ptr, voidpf ptr),PNG_EMPTY);
898 
899 /* Next four functions are used internally as callbacks.  PNGCBAPI is required
900  * but not PNG_EXPORT.  PNGAPI added at libpng version 1.2.3, changed to
901  * PNGCBAPI at 1.5.0
902  */
903 
904 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_read_data,(png_structp png_ptr,
905     png_bytep data, png_size_t length),PNG_EMPTY);
906 
907 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
908 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_push_fill_buffer,(png_structp png_ptr,
909     png_bytep buffer, png_size_t length),PNG_EMPTY);
910 #endif
911 
912 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_write_data,(png_structp png_ptr,
913     png_bytep data, png_size_t length),PNG_EMPTY);
914 
915 #ifdef PNG_WRITE_FLUSH_SUPPORTED
916 #  ifdef PNG_STDIO_SUPPORTED
917 PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_flush,(png_structp png_ptr),
918    PNG_EMPTY);
919 #  endif
920 #endif
921 
922 /* Reset the CRC variable */
923 PNG_INTERNAL_FUNCTION(void,png_reset_crc,(png_structrp png_ptr),PNG_EMPTY);
924 
925 /* Write the "data" buffer to whatever output you are using */
926 PNG_INTERNAL_FUNCTION(void,png_write_data,(png_structrp png_ptr,
927     png_const_bytep data, png_size_t length),PNG_EMPTY);
928 
929 /* Read and check the PNG file signature */
930 PNG_INTERNAL_FUNCTION(void,png_read_sig,(png_structrp png_ptr,
931    png_inforp info_ptr),PNG_EMPTY);
932 
933 /* Read the chunk header (length + type name) */
934 PNG_INTERNAL_FUNCTION(png_uint_32,png_read_chunk_header,(png_structrp png_ptr),
935    PNG_EMPTY);
936 
937 /* Read data from whatever input you are using into the "data" buffer */
938 PNG_INTERNAL_FUNCTION(void,png_read_data,(png_structrp png_ptr, png_bytep data,
939     png_size_t length),PNG_EMPTY);
940 
941 /* Read bytes into buf, and update png_ptr->crc */
942 PNG_INTERNAL_FUNCTION(void,png_crc_read,(png_structrp png_ptr, png_bytep buf,
943     png_uint_32 length),PNG_EMPTY);
944 
945 /* Read "skip" bytes, read the file crc, and (optionally) verify png_ptr->crc */
946 PNG_INTERNAL_FUNCTION(int,png_crc_finish,(png_structrp png_ptr,
947    png_uint_32 skip),PNG_EMPTY);
948 
949 /* Read the CRC from the file and compare it to the libpng calculated CRC */
950 PNG_INTERNAL_FUNCTION(int,png_crc_error,(png_structrp png_ptr),PNG_EMPTY);
951 
952 /* Calculate the CRC over a section of data.  Note that we are only
953  * passing a maximum of 64K on systems that have this as a memory limit,
954  * since this is the maximum buffer size we can specify.
955  */
956 PNG_INTERNAL_FUNCTION(void,png_calculate_crc,(png_structrp png_ptr,
957    png_const_bytep ptr, png_size_t length),PNG_EMPTY);
958 
959 #ifdef PNG_WRITE_FLUSH_SUPPORTED
960 PNG_INTERNAL_FUNCTION(void,png_flush,(png_structrp png_ptr),PNG_EMPTY);
961 #endif
962 
963 /* Write various chunks */
964 
965 /* Write the IHDR chunk, and update the png_struct with the necessary
966  * information.
967  */
968 PNG_INTERNAL_FUNCTION(void,png_write_IHDR,(png_structrp png_ptr,
969    png_uint_32 width, png_uint_32 height, int bit_depth, int color_type,
970    int compression_method, int filter_method, int interlace_method),PNG_EMPTY);
971 
972 PNG_INTERNAL_FUNCTION(void,png_write_PLTE,(png_structrp png_ptr,
973    png_const_colorp palette, png_uint_32 num_pal),PNG_EMPTY);
974 
975 PNG_INTERNAL_FUNCTION(void,png_compress_IDAT,(png_structrp png_ptr,
976    png_const_bytep row_data, png_alloc_size_t row_data_length, int flush),
977    PNG_EMPTY);
978 
979 PNG_INTERNAL_FUNCTION(void,png_write_IEND,(png_structrp png_ptr),PNG_EMPTY);
980 
981 #ifdef PNG_WRITE_gAMA_SUPPORTED
982 PNG_INTERNAL_FUNCTION(void,png_write_gAMA_fixed,(png_structrp png_ptr,
983     png_fixed_point file_gamma),PNG_EMPTY);
984 #endif
985 
986 #ifdef PNG_WRITE_sBIT_SUPPORTED
987 PNG_INTERNAL_FUNCTION(void,png_write_sBIT,(png_structrp png_ptr,
988     png_const_color_8p sbit, int color_type),PNG_EMPTY);
989 #endif
990 
991 #ifdef PNG_WRITE_cHRM_SUPPORTED
992 PNG_INTERNAL_FUNCTION(void,png_write_cHRM_fixed,(png_structrp png_ptr,
993     const png_xy *xy), PNG_EMPTY);
994     /* The xy value must have been previously validated */
995 #endif
996 
997 #ifdef PNG_WRITE_sRGB_SUPPORTED
998 PNG_INTERNAL_FUNCTION(void,png_write_sRGB,(png_structrp png_ptr,
999     int intent),PNG_EMPTY);
1000 #endif
1001 
1002 #ifdef PNG_WRITE_iCCP_SUPPORTED
1003 PNG_INTERNAL_FUNCTION(void,png_write_iCCP,(png_structrp png_ptr,
1004    png_const_charp name, png_const_bytep profile), PNG_EMPTY);
1005    /* The profile must have been previously validated for correctness, the
1006     * length comes from the first four bytes.  Only the base, deflate,
1007     * compression is supported.
1008     */
1009 #endif
1010 
1011 #ifdef PNG_WRITE_sPLT_SUPPORTED
1012 PNG_INTERNAL_FUNCTION(void,png_write_sPLT,(png_structrp png_ptr,
1013     png_const_sPLT_tp palette),PNG_EMPTY);
1014 #endif
1015 
1016 #ifdef PNG_WRITE_tRNS_SUPPORTED
1017 PNG_INTERNAL_FUNCTION(void,png_write_tRNS,(png_structrp png_ptr,
1018     png_const_bytep trans, png_const_color_16p values, int number,
1019     int color_type),PNG_EMPTY);
1020 #endif
1021 
1022 #ifdef PNG_WRITE_bKGD_SUPPORTED
1023 PNG_INTERNAL_FUNCTION(void,png_write_bKGD,(png_structrp png_ptr,
1024     png_const_color_16p values, int color_type),PNG_EMPTY);
1025 #endif
1026 
1027 #ifdef PNG_WRITE_hIST_SUPPORTED
1028 PNG_INTERNAL_FUNCTION(void,png_write_hIST,(png_structrp png_ptr,
1029     png_const_uint_16p hist, int num_hist),PNG_EMPTY);
1030 #endif
1031 
1032 /* Chunks that have keywords */
1033 #ifdef PNG_WRITE_tEXt_SUPPORTED
1034 PNG_INTERNAL_FUNCTION(void,png_write_tEXt,(png_structrp png_ptr,
1035    png_const_charp key, png_const_charp text, png_size_t text_len),PNG_EMPTY);
1036 #endif
1037 
1038 #ifdef PNG_WRITE_zTXt_SUPPORTED
1039 PNG_INTERNAL_FUNCTION(void,png_write_zTXt,(png_structrp png_ptr, png_const_charp
1040     key, png_const_charp text, png_size_t text_len, int compression),PNG_EMPTY);
1041 #endif
1042 
1043 #ifdef PNG_WRITE_iTXt_SUPPORTED
1044 PNG_INTERNAL_FUNCTION(void,png_write_iTXt,(png_structrp png_ptr,
1045     int compression, png_const_charp key, png_const_charp lang,
1046     png_const_charp lang_key, png_const_charp text),PNG_EMPTY);
1047 #endif
1048 
1049 #ifdef PNG_TEXT_SUPPORTED  /* Added at version 1.0.14 and 1.2.4 */
1050 PNG_INTERNAL_FUNCTION(int,png_set_text_2,(png_const_structrp png_ptr,
1051     png_inforp info_ptr, png_const_textp text_ptr, int num_text),PNG_EMPTY);
1052 #endif
1053 
1054 #ifdef PNG_WRITE_oFFs_SUPPORTED
1055 PNG_INTERNAL_FUNCTION(void,png_write_oFFs,(png_structrp png_ptr,
1056     png_int_32 x_offset, png_int_32 y_offset, int unit_type),PNG_EMPTY);
1057 #endif
1058 
1059 #ifdef PNG_WRITE_pCAL_SUPPORTED
1060 PNG_INTERNAL_FUNCTION(void,png_write_pCAL,(png_structrp png_ptr,
1061     png_charp purpose, png_int_32 X0, png_int_32 X1, int type, int nparams,
1062     png_const_charp units, png_charpp params),PNG_EMPTY);
1063 #endif
1064 
1065 #ifdef PNG_WRITE_pHYs_SUPPORTED
1066 PNG_INTERNAL_FUNCTION(void,png_write_pHYs,(png_structrp png_ptr,
1067     png_uint_32 x_pixels_per_unit, png_uint_32 y_pixels_per_unit,
1068     int unit_type),PNG_EMPTY);
1069 #endif
1070 
1071 #ifdef PNG_WRITE_tIME_SUPPORTED
1072 PNG_INTERNAL_FUNCTION(void,png_write_tIME,(png_structrp png_ptr,
1073     png_const_timep mod_time),PNG_EMPTY);
1074 #endif
1075 
1076 #ifdef PNG_WRITE_sCAL_SUPPORTED
1077 PNG_INTERNAL_FUNCTION(void,png_write_sCAL_s,(png_structrp png_ptr,
1078     int unit, png_const_charp width, png_const_charp height),PNG_EMPTY);
1079 #endif
1080 
1081 /* Called when finished processing a row of data */
1082 PNG_INTERNAL_FUNCTION(void,png_write_finish_row,(png_structrp png_ptr),
1083     PNG_EMPTY);
1084 
1085 /* Internal use only.   Called before first row of data */
1086 PNG_INTERNAL_FUNCTION(void,png_write_start_row,(png_structrp png_ptr),
1087     PNG_EMPTY);
1088 
1089 /* Combine a row of data, dealing with alpha, etc. if requested.  'row' is an
1090  * array of png_ptr->width pixels.  If the image is not interlaced or this
1091  * is the final pass this just does a memcpy, otherwise the "display" flag
1092  * is used to determine whether to copy pixels that are not in the current pass.
1093  *
1094  * Because 'png_do_read_interlace' (below) replicates pixels this allows this
1095  * function to achieve the documented 'blocky' appearance during interlaced read
1096  * if display is 1 and the 'sparkle' appearance, where existing pixels in 'row'
1097  * are not changed if they are not in the current pass, when display is 0.
1098  *
1099  * 'display' must be 0 or 1, otherwise the memcpy will be done regardless.
1100  *
1101  * The API always reads from the png_struct row buffer and always assumes that
1102  * it is full width (png_do_read_interlace has already been called.)
1103  *
1104  * This function is only ever used to write to row buffers provided by the
1105  * caller of the relevant libpng API and the row must have already been
1106  * transformed by the read transformations.
1107  *
1108  * The PNG_USE_COMPILE_TIME_MASKS option causes generation of pre-computed
1109  * bitmasks for use within the code, otherwise runtime generated masks are used.
1110  * The default is compile time masks.
1111  */
1112 #ifndef PNG_USE_COMPILE_TIME_MASKS
1113 #  define PNG_USE_COMPILE_TIME_MASKS 1
1114 #endif
1115 PNG_INTERNAL_FUNCTION(void,png_combine_row,(png_const_structrp png_ptr,
1116     png_bytep row, int display),PNG_EMPTY);
1117 
1118 #ifdef PNG_READ_INTERLACING_SUPPORTED
1119 /* Expand an interlaced row: the 'row_info' describes the pass data that has
1120  * been read in and must correspond to the pixels in 'row', the pixels are
1121  * expanded (moved apart) in 'row' to match the final layout, when doing this
1122  * the pixels are *replicated* to the intervening space.  This is essential for
1123  * the correct operation of png_combine_row, above.
1124  */
1125 PNG_INTERNAL_FUNCTION(void,png_do_read_interlace,(png_row_infop row_info,
1126     png_bytep row, int pass, png_uint_32 transformations),PNG_EMPTY);
1127 #endif
1128 
1129 /* GRR TO DO (2.0 or whenever):  simplify other internal calling interfaces */
1130 
1131 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1132 /* Grab pixels out of a row for an interlaced pass */
1133 PNG_INTERNAL_FUNCTION(void,png_do_write_interlace,(png_row_infop row_info,
1134     png_bytep row, int pass),PNG_EMPTY);
1135 #endif
1136 
1137 /* Unfilter a row: check the filter value before calling this, there is no point
1138  * calling it for PNG_FILTER_VALUE_NONE.
1139  */
1140 PNG_INTERNAL_FUNCTION(void,png_read_filter_row,(png_structrp pp, png_row_infop
1141     row_info, png_bytep row, png_const_bytep prev_row, int filter),PNG_EMPTY);
1142 
1143 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_up_neon,(png_row_infop row_info,
1144     png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1145 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_neon,(png_row_infop
1146     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1147 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_neon,(png_row_infop
1148     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1149 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_neon,(png_row_infop
1150     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1151 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_neon,(png_row_infop
1152     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1153 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_neon,(png_row_infop
1154     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1155 PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_neon,(png_row_infop
1156     row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
1157 
1158 /* Choose the best filter to use and filter the row data */
1159 PNG_INTERNAL_FUNCTION(void,png_write_find_filter,(png_structrp png_ptr,
1160     png_row_infop row_info),PNG_EMPTY);
1161 
1162 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1163 PNG_INTERNAL_FUNCTION(void,png_read_IDAT_data,(png_structrp png_ptr,
1164    png_bytep output, png_alloc_size_t avail_out),PNG_EMPTY);
1165    /* Read 'avail_out' bytes of data from the IDAT stream.  If the output buffer
1166     * is NULL the function checks, instead, for the end of the stream.  In this
1167     * case a benign error will be issued if the stream end is not found or if
1168     * extra data has to be consumed.
1169     */
1170 PNG_INTERNAL_FUNCTION(void,png_read_finish_IDAT,(png_structrp png_ptr),
1171    PNG_EMPTY);
1172    /* This cleans up when the IDAT LZ stream does not end when the last image
1173     * byte is read; there is still some pending input.
1174     */
1175 
1176 PNG_INTERNAL_FUNCTION(void,png_read_finish_row,(png_structrp png_ptr),
1177    PNG_EMPTY);
1178    /* Finish a row while reading, dealing with interlacing passes, etc. */
1179 #endif
1180 
1181 /* Initialize the row buffers, etc. */
1182 PNG_INTERNAL_FUNCTION(void,png_read_start_row,(png_structrp png_ptr),PNG_EMPTY);
1183 
1184 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1185 /* Optional call to update the users info structure */
1186 PNG_INTERNAL_FUNCTION(void,png_read_transform_info,(png_structrp png_ptr,
1187     png_inforp info_ptr),PNG_EMPTY);
1188 #endif
1189 
1190 /* These are the functions that do the transformations */
1191 #ifdef PNG_READ_FILLER_SUPPORTED
1192 PNG_INTERNAL_FUNCTION(void,png_do_read_filler,(png_row_infop row_info,
1193     png_bytep row, png_uint_32 filler, png_uint_32 flags),PNG_EMPTY);
1194 #endif
1195 
1196 #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
1197 PNG_INTERNAL_FUNCTION(void,png_do_read_swap_alpha,(png_row_infop row_info,
1198     png_bytep row),PNG_EMPTY);
1199 #endif
1200 
1201 #ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
1202 PNG_INTERNAL_FUNCTION(void,png_do_write_swap_alpha,(png_row_infop row_info,
1203     png_bytep row),PNG_EMPTY);
1204 #endif
1205 
1206 #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
1207 PNG_INTERNAL_FUNCTION(void,png_do_read_invert_alpha,(png_row_infop row_info,
1208     png_bytep row),PNG_EMPTY);
1209 #endif
1210 
1211 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
1212 PNG_INTERNAL_FUNCTION(void,png_do_write_invert_alpha,(png_row_infop row_info,
1213     png_bytep row),PNG_EMPTY);
1214 #endif
1215 
1216 #if defined(PNG_WRITE_FILLER_SUPPORTED) || \
1217     defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
1218 PNG_INTERNAL_FUNCTION(void,png_do_strip_channel,(png_row_infop row_info,
1219     png_bytep row, int at_start),PNG_EMPTY);
1220 #endif
1221 
1222 #ifdef PNG_16BIT_SUPPORTED
1223 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
1224 PNG_INTERNAL_FUNCTION(void,png_do_swap,(png_row_infop row_info,
1225     png_bytep row),PNG_EMPTY);
1226 #endif
1227 #endif
1228 
1229 #if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
1230     defined(PNG_WRITE_PACKSWAP_SUPPORTED)
1231 PNG_INTERNAL_FUNCTION(void,png_do_packswap,(png_row_infop row_info,
1232     png_bytep row),PNG_EMPTY);
1233 #endif
1234 
1235 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1236 PNG_INTERNAL_FUNCTION(int,png_do_rgb_to_gray,(png_structrp png_ptr,
1237     png_row_infop row_info, png_bytep row),PNG_EMPTY);
1238 #endif
1239 
1240 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
1241 PNG_INTERNAL_FUNCTION(void,png_do_gray_to_rgb,(png_row_infop row_info,
1242     png_bytep row),PNG_EMPTY);
1243 #endif
1244 
1245 #ifdef PNG_READ_PACK_SUPPORTED
1246 PNG_INTERNAL_FUNCTION(void,png_do_unpack,(png_row_infop row_info,
1247     png_bytep row),PNG_EMPTY);
1248 #endif
1249 
1250 #ifdef PNG_READ_SHIFT_SUPPORTED
1251 PNG_INTERNAL_FUNCTION(void,png_do_unshift,(png_row_infop row_info,
1252     png_bytep row, png_const_color_8p sig_bits),PNG_EMPTY);
1253 #endif
1254 
1255 #if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
1256 PNG_INTERNAL_FUNCTION(void,png_do_invert,(png_row_infop row_info,
1257     png_bytep row),PNG_EMPTY);
1258 #endif
1259 
1260 #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
1261 PNG_INTERNAL_FUNCTION(void,png_do_scale_16_to_8,(png_row_infop row_info,
1262     png_bytep row),PNG_EMPTY);
1263 #endif
1264 
1265 #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
1266 PNG_INTERNAL_FUNCTION(void,png_do_chop,(png_row_infop row_info,
1267     png_bytep row),PNG_EMPTY);
1268 #endif
1269 
1270 #ifdef PNG_READ_QUANTIZE_SUPPORTED
1271 PNG_INTERNAL_FUNCTION(void,png_do_quantize,(png_row_infop row_info,
1272     png_bytep row, png_const_bytep palette_lookup,
1273     png_const_bytep quantize_lookup),PNG_EMPTY);
1274 
1275 #  ifdef PNG_CORRECT_PALETTE_SUPPORTED
1276 PNG_INTERNAL_FUNCTION(void,png_correct_palette,(png_structrp png_ptr,
1277     png_colorp palette, int num_palette),PNG_EMPTY);
1278 #  endif
1279 #endif
1280 
1281 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
1282 PNG_INTERNAL_FUNCTION(void,png_do_bgr,(png_row_infop row_info,
1283     png_bytep row),PNG_EMPTY);
1284 #endif
1285 
1286 #ifdef PNG_WRITE_PACK_SUPPORTED
1287 PNG_INTERNAL_FUNCTION(void,png_do_pack,(png_row_infop row_info,
1288    png_bytep row, png_uint_32 bit_depth),PNG_EMPTY);
1289 #endif
1290 
1291 #ifdef PNG_WRITE_SHIFT_SUPPORTED
1292 PNG_INTERNAL_FUNCTION(void,png_do_shift,(png_row_infop row_info,
1293     png_bytep row, png_const_color_8p bit_depth),PNG_EMPTY);
1294 #endif
1295 
1296 #if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
1297     defined(PNG_READ_ALPHA_MODE_SUPPORTED)
1298 PNG_INTERNAL_FUNCTION(void,png_do_compose,(png_row_infop row_info,
1299     png_bytep row, png_structrp png_ptr),PNG_EMPTY);
1300 #endif
1301 
1302 #ifdef PNG_READ_GAMMA_SUPPORTED
1303 PNG_INTERNAL_FUNCTION(void,png_do_gamma,(png_row_infop row_info,
1304     png_bytep row, png_structrp png_ptr),PNG_EMPTY);
1305 #endif
1306 
1307 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
1308 PNG_INTERNAL_FUNCTION(void,png_do_encode_alpha,(png_row_infop row_info,
1309    png_bytep row, png_structrp png_ptr),PNG_EMPTY);
1310 #endif
1311 
1312 #ifdef PNG_READ_EXPAND_SUPPORTED
1313 PNG_INTERNAL_FUNCTION(void,png_do_expand_palette,(png_row_infop row_info,
1314     png_bytep row, png_const_colorp palette, png_const_bytep trans,
1315     int num_trans),PNG_EMPTY);
1316 PNG_INTERNAL_FUNCTION(void,png_do_expand,(png_row_infop row_info,
1317     png_bytep row, png_const_color_16p trans_color),PNG_EMPTY);
1318 #endif
1319 
1320 #ifdef PNG_READ_EXPAND_16_SUPPORTED
1321 PNG_INTERNAL_FUNCTION(void,png_do_expand_16,(png_row_infop row_info,
1322     png_bytep row),PNG_EMPTY);
1323 #endif
1324 
1325 /* The following decodes the appropriate chunks, and does error correction,
1326  * then calls the appropriate callback for the chunk if it is valid.
1327  */
1328 
1329 /* Decode the IHDR chunk */
1330 PNG_INTERNAL_FUNCTION(void,png_handle_IHDR,(png_structrp png_ptr,
1331     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1332 PNG_INTERNAL_FUNCTION(void,png_handle_PLTE,(png_structrp png_ptr,
1333     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1334 PNG_INTERNAL_FUNCTION(void,png_handle_IEND,(png_structrp png_ptr,
1335     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1336 
1337 #ifdef PNG_READ_bKGD_SUPPORTED
1338 PNG_INTERNAL_FUNCTION(void,png_handle_bKGD,(png_structrp png_ptr,
1339     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1340 #endif
1341 
1342 #ifdef PNG_READ_cHRM_SUPPORTED
1343 PNG_INTERNAL_FUNCTION(void,png_handle_cHRM,(png_structrp png_ptr,
1344     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1345 #endif
1346 
1347 #ifdef PNG_READ_gAMA_SUPPORTED
1348 PNG_INTERNAL_FUNCTION(void,png_handle_gAMA,(png_structrp png_ptr,
1349     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1350 #endif
1351 
1352 #ifdef PNG_READ_hIST_SUPPORTED
1353 PNG_INTERNAL_FUNCTION(void,png_handle_hIST,(png_structrp png_ptr,
1354     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1355 #endif
1356 
1357 #ifdef PNG_READ_iCCP_SUPPORTED
1358 PNG_INTERNAL_FUNCTION(void,png_handle_iCCP,(png_structrp png_ptr,
1359     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1360 #endif /* PNG_READ_iCCP_SUPPORTED */
1361 
1362 #ifdef PNG_READ_iTXt_SUPPORTED
1363 PNG_INTERNAL_FUNCTION(void,png_handle_iTXt,(png_structrp png_ptr,
1364     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1365 #endif
1366 
1367 #ifdef PNG_READ_oFFs_SUPPORTED
1368 PNG_INTERNAL_FUNCTION(void,png_handle_oFFs,(png_structrp png_ptr,
1369     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1370 #endif
1371 
1372 #ifdef PNG_READ_pCAL_SUPPORTED
1373 PNG_INTERNAL_FUNCTION(void,png_handle_pCAL,(png_structrp png_ptr,
1374     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1375 #endif
1376 
1377 #ifdef PNG_READ_pHYs_SUPPORTED
1378 PNG_INTERNAL_FUNCTION(void,png_handle_pHYs,(png_structrp png_ptr,
1379     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1380 #endif
1381 
1382 #ifdef PNG_READ_sBIT_SUPPORTED
1383 PNG_INTERNAL_FUNCTION(void,png_handle_sBIT,(png_structrp png_ptr,
1384     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1385 #endif
1386 
1387 #ifdef PNG_READ_sCAL_SUPPORTED
1388 PNG_INTERNAL_FUNCTION(void,png_handle_sCAL,(png_structrp png_ptr,
1389     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1390 #endif
1391 
1392 #ifdef PNG_READ_sPLT_SUPPORTED
1393 PNG_INTERNAL_FUNCTION(void,png_handle_sPLT,(png_structrp png_ptr,
1394     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1395 #endif /* PNG_READ_sPLT_SUPPORTED */
1396 
1397 #ifdef PNG_READ_sRGB_SUPPORTED
1398 PNG_INTERNAL_FUNCTION(void,png_handle_sRGB,(png_structrp png_ptr,
1399     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1400 #endif
1401 
1402 #ifdef PNG_READ_tEXt_SUPPORTED
1403 PNG_INTERNAL_FUNCTION(void,png_handle_tEXt,(png_structrp png_ptr,
1404     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1405 #endif
1406 
1407 #ifdef PNG_READ_tIME_SUPPORTED
1408 PNG_INTERNAL_FUNCTION(void,png_handle_tIME,(png_structrp png_ptr,
1409     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1410 #endif
1411 
1412 #ifdef PNG_READ_tRNS_SUPPORTED
1413 PNG_INTERNAL_FUNCTION(void,png_handle_tRNS,(png_structrp png_ptr,
1414     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1415 #endif
1416 
1417 #ifdef PNG_READ_zTXt_SUPPORTED
1418 PNG_INTERNAL_FUNCTION(void,png_handle_zTXt,(png_structrp png_ptr,
1419     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1420 #endif
1421 
1422 PNG_INTERNAL_FUNCTION(void,png_check_chunk_name,(png_structrp png_ptr,
1423     png_uint_32 chunk_name),PNG_EMPTY);
1424 
1425 #ifdef PNG_READ_SUPPORTED
1426 PNG_INTERNAL_FUNCTION(void,png_handle_unknown,(png_structrp png_ptr,
1427     png_inforp info_ptr, png_uint_32 length, int keep),PNG_EMPTY);
1428    /* This is the function that gets called for unknown chunks.  The 'keep'
1429     * argument is either non-zero for a known chunk that has been set to be
1430     * handled as unknown or zero for an unknown chunk.  By default the function
1431     * just skips the chunk or errors out if it is critical.
1432     */
1433 
1434 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
1435 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
1436 PNG_INTERNAL_FUNCTION(int,png_chunk_unknown_handling,
1437     (png_const_structrp png_ptr, png_uint_32 chunk_name),PNG_EMPTY);
1438    /* Exactly as the API png_handle_as_unknown() except that the argument is a
1439     * 32-bit chunk name, not a string.
1440     */
1441 #endif
1442 #endif /* PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */
1443 #endif /* PNG_READ_SUPPORTED */
1444 
1445 /* Handle the transformations for reading and writing */
1446 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1447 PNG_INTERNAL_FUNCTION(void,png_do_read_transformations,(png_structrp png_ptr,
1448    png_row_infop row_info),PNG_EMPTY);
1449 #endif
1450 #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
1451 PNG_INTERNAL_FUNCTION(void,png_do_write_transformations,(png_structrp png_ptr,
1452    png_row_infop row_info),PNG_EMPTY);
1453 #endif
1454 
1455 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1456 PNG_INTERNAL_FUNCTION(void,png_init_read_transformations,(png_structrp png_ptr),
1457     PNG_EMPTY);
1458 #endif
1459 
1460 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1461 PNG_INTERNAL_FUNCTION(void,png_push_read_chunk,(png_structrp png_ptr,
1462     png_inforp info_ptr),PNG_EMPTY);
1463 PNG_INTERNAL_FUNCTION(void,png_push_read_sig,(png_structrp png_ptr,
1464     png_inforp info_ptr),PNG_EMPTY);
1465 PNG_INTERNAL_FUNCTION(void,png_push_check_crc,(png_structrp png_ptr),PNG_EMPTY);
1466 PNG_INTERNAL_FUNCTION(void,png_push_crc_skip,(png_structrp png_ptr,
1467     png_uint_32 length),PNG_EMPTY);
1468 PNG_INTERNAL_FUNCTION(void,png_push_crc_finish,(png_structrp png_ptr),
1469     PNG_EMPTY);
1470 PNG_INTERNAL_FUNCTION(void,png_push_save_buffer,(png_structrp png_ptr),
1471     PNG_EMPTY);
1472 PNG_INTERNAL_FUNCTION(void,png_push_restore_buffer,(png_structrp png_ptr,
1473     png_bytep buffer, png_size_t buffer_length),PNG_EMPTY);
1474 PNG_INTERNAL_FUNCTION(void,png_push_read_IDAT,(png_structrp png_ptr),PNG_EMPTY);
1475 PNG_INTERNAL_FUNCTION(void,png_process_IDAT_data,(png_structrp png_ptr,
1476     png_bytep buffer, png_size_t buffer_length),PNG_EMPTY);
1477 PNG_INTERNAL_FUNCTION(void,png_push_process_row,(png_structrp png_ptr),
1478     PNG_EMPTY);
1479 PNG_INTERNAL_FUNCTION(void,png_push_handle_unknown,(png_structrp png_ptr,
1480    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1481 PNG_INTERNAL_FUNCTION(void,png_push_have_info,(png_structrp png_ptr,
1482    png_inforp info_ptr),PNG_EMPTY);
1483 PNG_INTERNAL_FUNCTION(void,png_push_have_end,(png_structrp png_ptr,
1484    png_inforp info_ptr),PNG_EMPTY);
1485 PNG_INTERNAL_FUNCTION(void,png_push_have_row,(png_structrp png_ptr,
1486      png_bytep row),PNG_EMPTY);
1487 PNG_INTERNAL_FUNCTION(void,png_push_read_end,(png_structrp png_ptr,
1488     png_inforp info_ptr),PNG_EMPTY);
1489 PNG_INTERNAL_FUNCTION(void,png_process_some_data,(png_structrp png_ptr,
1490     png_inforp info_ptr),PNG_EMPTY);
1491 PNG_INTERNAL_FUNCTION(void,png_read_push_finish_row,(png_structrp png_ptr),
1492     PNG_EMPTY);
1493 #  ifdef PNG_READ_tEXt_SUPPORTED
1494 PNG_INTERNAL_FUNCTION(void,png_push_handle_tEXt,(png_structrp png_ptr,
1495     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1496 PNG_INTERNAL_FUNCTION(void,png_push_read_tEXt,(png_structrp png_ptr,
1497     png_inforp info_ptr),PNG_EMPTY);
1498 #  endif
1499 #  ifdef PNG_READ_zTXt_SUPPORTED
1500 PNG_INTERNAL_FUNCTION(void,png_push_handle_zTXt,(png_structrp png_ptr,
1501     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1502 PNG_INTERNAL_FUNCTION(void,png_push_read_zTXt,(png_structrp png_ptr,
1503     png_inforp info_ptr),PNG_EMPTY);
1504 #  endif
1505 #  ifdef PNG_READ_iTXt_SUPPORTED
1506 PNG_INTERNAL_FUNCTION(void,png_push_handle_iTXt,(png_structrp png_ptr,
1507     png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
1508 PNG_INTERNAL_FUNCTION(void,png_push_read_iTXt,(png_structrp png_ptr,
1509     png_inforp info_ptr),PNG_EMPTY);
1510 #  endif
1511 
1512 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
1513 
1514 #ifdef PNG_MNG_FEATURES_SUPPORTED
1515 PNG_INTERNAL_FUNCTION(void,png_do_read_intrapixel,(png_row_infop row_info,
1516     png_bytep row),PNG_EMPTY);
1517 PNG_INTERNAL_FUNCTION(void,png_do_write_intrapixel,(png_row_infop row_info,
1518     png_bytep row),PNG_EMPTY);
1519 #endif
1520 
1521 /* Added at libpng version 1.6.0 */
1522 #ifdef PNG_GAMMA_SUPPORTED
1523 PNG_INTERNAL_FUNCTION(void,png_colorspace_set_gamma,(png_const_structrp png_ptr,
1524     png_colorspacerp colorspace, png_fixed_point gAMA), PNG_EMPTY);
1525    /* Set the colorspace gamma with a value provided by the application or by
1526     * the gAMA chunk on read.  The value will override anything set by an ICC
1527     * profile.
1528     */
1529 
1530 PNG_INTERNAL_FUNCTION(void,png_colorspace_sync_info,(png_const_structrp png_ptr,
1531     png_inforp info_ptr), PNG_EMPTY);
1532     /* Synchronize the info 'valid' flags with the colorspace */
1533 
1534 PNG_INTERNAL_FUNCTION(void,png_colorspace_sync,(png_const_structrp png_ptr,
1535     png_inforp info_ptr), PNG_EMPTY);
1536     /* Copy the png_struct colorspace to the info_struct and call the above to
1537      * synchronize the flags.  Checks for NULL info_ptr and does nothing.
1538      */
1539 #endif
1540 
1541 /* Added at libpng version 1.4.0 */
1542 #ifdef PNG_COLORSPACE_SUPPORTED
1543 /* These internal functions are for maintaining the colorspace structure within
1544  * a png_info or png_struct (or, indeed, both).
1545  */
1546 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_chromaticities,
1547    (png_const_structrp png_ptr, png_colorspacerp colorspace, const png_xy *xy,
1548     int preferred), PNG_EMPTY);
1549 
1550 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_endpoints,
1551    (png_const_structrp png_ptr, png_colorspacerp colorspace, const png_XYZ *XYZ,
1552     int preferred), PNG_EMPTY);
1553 
1554 #ifdef PNG_sRGB_SUPPORTED
1555 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_sRGB,(png_const_structrp png_ptr,
1556    png_colorspacerp colorspace, int intent), PNG_EMPTY);
1557    /* This does set the colorspace gAMA and cHRM values too, but doesn't set the
1558     * flags to write them, if it returns false there was a problem and an error
1559     * message has already been output (but the colorspace may still need to be
1560     * synced to record the invalid flag).
1561     */
1562 #endif /* sRGB */
1563 
1564 #ifdef PNG_iCCP_SUPPORTED
1565 PNG_INTERNAL_FUNCTION(int,png_colorspace_set_ICC,(png_const_structrp png_ptr,
1566    png_colorspacerp colorspace, png_const_charp name,
1567    png_uint_32 profile_length, png_const_bytep profile, int color_type),
1568    PNG_EMPTY);
1569    /* The 'name' is used for information only */
1570 
1571 /* Routines for checking parts of an ICC profile. */
1572 PNG_INTERNAL_FUNCTION(int,png_icc_check_length,(png_const_structrp png_ptr,
1573    png_colorspacerp colorspace, png_const_charp name,
1574    png_uint_32 profile_length), PNG_EMPTY);
1575 PNG_INTERNAL_FUNCTION(int,png_icc_check_header,(png_const_structrp png_ptr,
1576    png_colorspacerp colorspace, png_const_charp name,
1577    png_uint_32 profile_length,
1578    png_const_bytep profile /* first 132 bytes only */, int color_type),
1579    PNG_EMPTY);
1580 PNG_INTERNAL_FUNCTION(int,png_icc_check_tag_table,(png_const_structrp png_ptr,
1581    png_colorspacerp colorspace, png_const_charp name,
1582    png_uint_32 profile_length,
1583    png_const_bytep profile /* header plus whole tag table */), PNG_EMPTY);
1584 #ifdef PNG_sRGB_SUPPORTED
1585 PNG_INTERNAL_FUNCTION(void,png_icc_set_sRGB,(
1586    png_const_structrp png_ptr, png_colorspacerp colorspace,
1587    png_const_bytep profile, uLong adler), PNG_EMPTY);
1588    /* 'adler' is the Adler32 checksum of the uncompressed profile data. It may
1589     * be zero to indicate that it is not available.  It is used, if provided,
1590     * as a fast check on the profile when checking to see if it is sRGB.
1591     */
1592 #endif
1593 #endif /* iCCP */
1594 
1595 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1596 PNG_INTERNAL_FUNCTION(void,png_colorspace_set_rgb_coefficients,
1597    (png_structrp png_ptr), PNG_EMPTY);
1598    /* Set the rgb_to_gray coefficients from the colorspace Y values */
1599 #endif /* READ_RGB_TO_GRAY */
1600 #endif /* COLORSPACE */
1601 
1602 /* Added at libpng version 1.4.0 */
1603 PNG_INTERNAL_FUNCTION(void,png_check_IHDR,(png_const_structrp png_ptr,
1604     png_uint_32 width, png_uint_32 height, int bit_depth,
1605     int color_type, int interlace_type, int compression_type,
1606     int filter_type),PNG_EMPTY);
1607 
1608 /* Added at libpng version 1.5.10 */
1609 #if defined(PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED) || \
1610     defined(PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED)
1611 PNG_INTERNAL_FUNCTION(void,png_do_check_palette_indexes,
1612    (png_structrp png_ptr, png_row_infop row_info),PNG_EMPTY);
1613 #endif
1614 
1615 #if defined(PNG_FLOATING_POINT_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED)
1616 PNG_INTERNAL_FUNCTION(void,png_fixed_error,(png_const_structrp png_ptr,
1617    png_const_charp name),PNG_NORETURN);
1618 #endif
1619 
1620 /* Puts 'string' into 'buffer' at buffer[pos], taking care never to overwrite
1621  * the end.  Always leaves the buffer nul terminated.  Never errors out (and
1622  * there is no error code.)
1623  */
1624 PNG_INTERNAL_FUNCTION(size_t,png_safecat,(png_charp buffer, size_t bufsize,
1625    size_t pos, png_const_charp string),PNG_EMPTY);
1626 
1627 /* Various internal functions to handle formatted warning messages, currently
1628  * only implemented for warnings.
1629  */
1630 #if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_TIME_RFC1123_SUPPORTED)
1631 /* Utility to dump an unsigned value into a buffer, given a start pointer and
1632  * and end pointer (which should point just *beyond* the end of the buffer!)
1633  * Returns the pointer to the start of the formatted string.  This utility only
1634  * does unsigned values.
1635  */
1636 PNG_INTERNAL_FUNCTION(png_charp,png_format_number,(png_const_charp start,
1637    png_charp end, int format, png_alloc_size_t number),PNG_EMPTY);
1638 
1639 /* Convenience macro that takes an array: */
1640 #define PNG_FORMAT_NUMBER(buffer,format,number) \
1641    png_format_number(buffer, buffer + (sizeof buffer), format, number)
1642 
1643 /* Suggested size for a number buffer (enough for 64 bits and a sign!) */
1644 #define PNG_NUMBER_BUFFER_SIZE 24
1645 
1646 /* These are the integer formats currently supported, the name is formed from
1647  * the standard printf(3) format string.
1648  */
1649 #define PNG_NUMBER_FORMAT_u     1 /* chose unsigned API! */
1650 #define PNG_NUMBER_FORMAT_02u   2
1651 #define PNG_NUMBER_FORMAT_d     1 /* chose signed API! */
1652 #define PNG_NUMBER_FORMAT_02d   2
1653 #define PNG_NUMBER_FORMAT_x     3
1654 #define PNG_NUMBER_FORMAT_02x   4
1655 #define PNG_NUMBER_FORMAT_fixed 5 /* choose the signed API */
1656 #endif
1657 
1658 #ifdef PNG_WARNINGS_SUPPORTED
1659 /* New defines and members adding in libpng-1.5.4 */
1660 #  define PNG_WARNING_PARAMETER_SIZE 32
1661 #  define PNG_WARNING_PARAMETER_COUNT 8 /* Maximum 9; see pngerror.c */
1662 
1663 /* An l-value of this type has to be passed to the APIs below to cache the
1664  * values of the parameters to a formatted warning message.
1665  */
1666 typedef char png_warning_parameters[PNG_WARNING_PARAMETER_COUNT][
1667    PNG_WARNING_PARAMETER_SIZE];
1668 
1669 PNG_INTERNAL_FUNCTION(void,png_warning_parameter,(png_warning_parameters p,
1670    int number, png_const_charp string),PNG_EMPTY);
1671    /* Parameters are limited in size to PNG_WARNING_PARAMETER_SIZE characters,
1672     * including the trailing '\0'.
1673     */
1674 PNG_INTERNAL_FUNCTION(void,png_warning_parameter_unsigned,
1675    (png_warning_parameters p, int number, int format, png_alloc_size_t value),
1676    PNG_EMPTY);
1677    /* Use png_alloc_size_t because it is an unsigned type as big as any we
1678     * need to output.  Use the following for a signed value.
1679     */
1680 PNG_INTERNAL_FUNCTION(void,png_warning_parameter_signed,
1681    (png_warning_parameters p, int number, int format, png_int_32 value),
1682    PNG_EMPTY);
1683 
1684 PNG_INTERNAL_FUNCTION(void,png_formatted_warning,(png_const_structrp png_ptr,
1685    png_warning_parameters p, png_const_charp message),PNG_EMPTY);
1686    /* 'message' follows the X/Open approach of using @1, @2 to insert
1687     * parameters previously supplied using the above functions.  Errors in
1688     * specifying the parameters will simply result in garbage substitutions.
1689     */
1690 #endif
1691 
1692 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
1693 /* Application errors (new in 1.6); use these functions (declared below) for
1694  * errors in the parameters or order of API function calls on read.  The
1695  * 'warning' should be used for an error that can be handled completely; the
1696  * 'error' for one which can be handled safely but which may lose application
1697  * information or settings.
1698  *
1699  * By default these both result in a png_error call prior to release, while in a
1700  * released version the 'warning' is just a warning.  However if the application
1701  * explicitly disables benign errors (explicitly permitting the code to lose
1702  * information) they both turn into warnings.
1703  *
1704  * If benign errors aren't supported they end up as the corresponding base call
1705  * (png_warning or png_error.)
1706  */
1707 PNG_INTERNAL_FUNCTION(void,png_app_warning,(png_const_structrp png_ptr,
1708    png_const_charp message),PNG_EMPTY);
1709    /* The application provided invalid parameters to an API function or called
1710     * an API function at the wrong time, libpng can completely recover.
1711     */
1712 
1713 PNG_INTERNAL_FUNCTION(void,png_app_error,(png_const_structrp png_ptr,
1714    png_const_charp message),PNG_EMPTY);
1715    /* As above but libpng will ignore the call, or attempt some other partial
1716     * recovery from the error.
1717     */
1718 #else
1719 #  define png_app_warning(pp,s) png_warning(pp,s)
1720 #  define png_app_error(pp,s) png_error(pp,s)
1721 #endif
1722 
1723 PNG_INTERNAL_FUNCTION(void,png_chunk_report,(png_const_structrp png_ptr,
1724    png_const_charp message, int error),PNG_EMPTY);
1725    /* Report a recoverable issue in chunk data.  On read this is used to report
1726     * a problem found while reading a particular chunk and the
1727     * png_chunk_benign_error or png_chunk_warning function is used as
1728     * appropriate.  On write this is used to report an error that comes from
1729     * data set via an application call to a png_set_ API and png_app_error or
1730     * png_app_warning is used as appropriate.
1731     *
1732     * The 'error' parameter must have one of the following values:
1733     */
1734 #define PNG_CHUNK_WARNING     0 /* never an error */
1735 #define PNG_CHUNK_WRITE_ERROR 1 /* an error only on write */
1736 #define PNG_CHUNK_ERROR       2 /* always an error */
1737 
1738 /* ASCII to FP interfaces, currently only implemented if sCAL
1739  * support is required.
1740  */
1741 #if defined(PNG_sCAL_SUPPORTED)
1742 /* MAX_DIGITS is actually the maximum number of characters in an sCAL
1743  * width or height, derived from the precision (number of significant
1744  * digits - a build time settable option) and assumptions about the
1745  * maximum ridiculous exponent.
1746  */
1747 #define PNG_sCAL_MAX_DIGITS (PNG_sCAL_PRECISION+1/*.*/+1/*E*/+10/*exponent*/)
1748 
1749 #ifdef PNG_FLOATING_POINT_SUPPORTED
1750 PNG_INTERNAL_FUNCTION(void,png_ascii_from_fp,(png_const_structrp png_ptr,
1751    png_charp ascii, png_size_t size, double fp, unsigned int precision),
1752    PNG_EMPTY);
1753 #endif /* FLOATING_POINT */
1754 
1755 #ifdef PNG_FIXED_POINT_SUPPORTED
1756 PNG_INTERNAL_FUNCTION(void,png_ascii_from_fixed,(png_const_structrp png_ptr,
1757    png_charp ascii, png_size_t size, png_fixed_point fp),PNG_EMPTY);
1758 #endif /* FIXED_POINT */
1759 #endif /* sCAL */
1760 
1761 #if defined(PNG_sCAL_SUPPORTED) || defined(PNG_pCAL_SUPPORTED)
1762 /* An internal API to validate the format of a floating point number.
1763  * The result is the index of the next character.  If the number is
1764  * not valid it will be the index of a character in the supposed number.
1765  *
1766  * The format of a number is defined in the PNG extensions specification
1767  * and this API is strictly conformant to that spec, not anyone elses!
1768  *
1769  * The format as a regular expression is:
1770  *
1771  * [+-]?[0-9]+.?([Ee][+-]?[0-9]+)?
1772  *
1773  * or:
1774  *
1775  * [+-]?.[0-9]+(.[0-9]+)?([Ee][+-]?[0-9]+)?
1776  *
1777  * The complexity is that either integer or fraction must be present and the
1778  * fraction is permitted to have no digits only if the integer is present.
1779  *
1780  * NOTE: The dangling E problem.
1781  *   There is a PNG valid floating point number in the following:
1782  *
1783  *       PNG floating point numbers are not greedy.
1784  *
1785  *   Working this out requires *TWO* character lookahead (because of the
1786  *   sign), the parser does not do this - it will fail at the 'r' - this
1787  *   doesn't matter for PNG sCAL chunk values, but it requires more care
1788  *   if the value were ever to be embedded in something more complex.  Use
1789  *   ANSI-C strtod if you need the lookahead.
1790  */
1791 /* State table for the parser. */
1792 #define PNG_FP_INTEGER    0  /* before or in integer */
1793 #define PNG_FP_FRACTION   1  /* before or in fraction */
1794 #define PNG_FP_EXPONENT   2  /* before or in exponent */
1795 #define PNG_FP_STATE      3  /* mask for the above */
1796 #define PNG_FP_SAW_SIGN   4  /* Saw +/- in current state */
1797 #define PNG_FP_SAW_DIGIT  8  /* Saw a digit in current state */
1798 #define PNG_FP_SAW_DOT   16  /* Saw a dot in current state */
1799 #define PNG_FP_SAW_E     32  /* Saw an E (or e) in current state */
1800 #define PNG_FP_SAW_ANY   60  /* Saw any of the above 4 */
1801 
1802 /* These three values don't affect the parser.  They are set but not used.
1803  */
1804 #define PNG_FP_WAS_VALID 64  /* Preceding substring is a valid fp number */
1805 #define PNG_FP_NEGATIVE 128  /* A negative number, including "-0" */
1806 #define PNG_FP_NONZERO  256  /* A non-zero value */
1807 #define PNG_FP_STICKY   448  /* The above three flags */
1808 
1809 /* This is available for the caller to store in 'state' if required.  Do not
1810  * call the parser after setting it (the parser sometimes clears it.)
1811  */
1812 #define PNG_FP_INVALID  512  /* Available for callers as a distinct value */
1813 
1814 /* Result codes for the parser (boolean - true meants ok, false means
1815  * not ok yet.)
1816  */
1817 #define PNG_FP_MAYBE      0  /* The number may be valid in the future */
1818 #define PNG_FP_OK         1  /* The number is valid */
1819 
1820 /* Tests on the sticky non-zero and negative flags.  To pass these checks
1821  * the state must also indicate that the whole number is valid - this is
1822  * achieved by testing PNG_FP_SAW_DIGIT (see the implementation for why this
1823  * is equivalent to PNG_FP_OK above.)
1824  */
1825 #define PNG_FP_NZ_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NEGATIVE | PNG_FP_NONZERO)
1826    /* NZ_MASK: the string is valid and a non-zero negative value */
1827 #define PNG_FP_Z_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NONZERO)
1828    /* Z MASK: the string is valid and a non-zero value. */
1829    /* PNG_FP_SAW_DIGIT: the string is valid. */
1830 #define PNG_FP_IS_ZERO(state) (((state) & PNG_FP_Z_MASK) == PNG_FP_SAW_DIGIT)
1831 #define PNG_FP_IS_POSITIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_Z_MASK)
1832 #define PNG_FP_IS_NEGATIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_NZ_MASK)
1833 
1834 /* The actual parser.  This can be called repeatedly. It updates
1835  * the index into the string and the state variable (which must
1836  * be initialized to 0).  It returns a result code, as above.  There
1837  * is no point calling the parser any more if it fails to advance to
1838  * the end of the string - it is stuck on an invalid character (or
1839  * terminated by '\0').
1840  *
1841  * Note that the pointer will consume an E or even an E+ and then leave
1842  * a 'maybe' state even though a preceding integer.fraction is valid.
1843  * The PNG_FP_WAS_VALID flag indicates that a preceding substring was
1844  * a valid number.  It's possible to recover from this by calling
1845  * the parser again (from the start, with state 0) but with a string
1846  * that omits the last character (i.e. set the size to the index of
1847  * the problem character.)  This has not been tested within libpng.
1848  */
1849 PNG_INTERNAL_FUNCTION(int,png_check_fp_number,(png_const_charp string,
1850    png_size_t size, int *statep, png_size_tp whereami),PNG_EMPTY);
1851 
1852 /* This is the same but it checks a complete string and returns true
1853  * only if it just contains a floating point number.  As of 1.5.4 this
1854  * function also returns the state at the end of parsing the number if
1855  * it was valid (otherwise it returns 0.)  This can be used for testing
1856  * for negative or zero values using the sticky flag.
1857  */
1858 PNG_INTERNAL_FUNCTION(int,png_check_fp_string,(png_const_charp string,
1859    png_size_t size),PNG_EMPTY);
1860 #endif /* pCAL || sCAL */
1861 
1862 #if defined(PNG_READ_GAMMA_SUPPORTED) ||\
1863     defined(PNG_INCH_CONVERSIONS_SUPPORTED) || defined(PNG_READ_pHYs_SUPPORTED)
1864 /* Added at libpng version 1.5.0 */
1865 /* This is a utility to provide a*times/div (rounded) and indicate
1866  * if there is an overflow.  The result is a boolean - false (0)
1867  * for overflow, true (1) if no overflow, in which case *res
1868  * holds the result.
1869  */
1870 PNG_INTERNAL_FUNCTION(int,png_muldiv,(png_fixed_point_p res, png_fixed_point a,
1871    png_int_32 multiplied_by, png_int_32 divided_by),PNG_EMPTY);
1872 #endif
1873 
1874 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_INCH_CONVERSIONS_SUPPORTED)
1875 /* Same deal, but issue a warning on overflow and return 0. */
1876 PNG_INTERNAL_FUNCTION(png_fixed_point,png_muldiv_warn,
1877    (png_const_structrp png_ptr, png_fixed_point a, png_int_32 multiplied_by,
1878    png_int_32 divided_by),PNG_EMPTY);
1879 #endif
1880 
1881 #ifdef PNG_GAMMA_SUPPORTED
1882 /* Calculate a reciprocal - used for gamma values.  This returns
1883  * 0 if the argument is 0 in order to maintain an undefined value;
1884  * there are no warnings.
1885  */
1886 PNG_INTERNAL_FUNCTION(png_fixed_point,png_reciprocal,(png_fixed_point a),
1887    PNG_EMPTY);
1888 
1889 #ifdef PNG_READ_GAMMA_SUPPORTED
1890 /* The same but gives a reciprocal of the product of two fixed point
1891  * values.  Accuracy is suitable for gamma calculations but this is
1892  * not exact - use png_muldiv for that.  Only required at present on read.
1893  */
1894 PNG_INTERNAL_FUNCTION(png_fixed_point,png_reciprocal2,(png_fixed_point a,
1895    png_fixed_point b),PNG_EMPTY);
1896 #endif
1897 
1898 /* Return true if the gamma value is significantly different from 1.0 */
1899 PNG_INTERNAL_FUNCTION(int,png_gamma_significant,(png_fixed_point gamma_value),
1900    PNG_EMPTY);
1901 #endif
1902 
1903 #ifdef PNG_READ_GAMMA_SUPPORTED
1904 /* Internal fixed point gamma correction.  These APIs are called as
1905  * required to convert single values - they don't need to be fast,
1906  * they are not used when processing image pixel values.
1907  *
1908  * While the input is an 'unsigned' value it must actually be the
1909  * correct bit value - 0..255 or 0..65535 as required.
1910  */
1911 PNG_INTERNAL_FUNCTION(png_uint_16,png_gamma_correct,(png_structrp png_ptr,
1912    unsigned int value, png_fixed_point gamma_value),PNG_EMPTY);
1913 PNG_INTERNAL_FUNCTION(png_uint_16,png_gamma_16bit_correct,(unsigned int value,
1914    png_fixed_point gamma_value),PNG_EMPTY);
1915 PNG_INTERNAL_FUNCTION(png_byte,png_gamma_8bit_correct,(unsigned int value,
1916    png_fixed_point gamma_value),PNG_EMPTY);
1917 PNG_INTERNAL_FUNCTION(void,png_destroy_gamma_table,(png_structrp png_ptr),
1918    PNG_EMPTY);
1919 PNG_INTERNAL_FUNCTION(void,png_build_gamma_table,(png_structrp png_ptr,
1920    int bit_depth),PNG_EMPTY);
1921 #endif
1922 
1923 /* SIMPLIFIED READ/WRITE SUPPORT */
1924 #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
1925    defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
1926 /* The internal structure that png_image::opaque points to. */
1927 typedef struct png_control
1928 {
1929    png_structp png_ptr;
1930    png_infop   info_ptr;
1931    png_voidp   error_buf;           /* Always a jmp_buf at present. */
1932 
1933    png_const_bytep memory;          /* Memory buffer. */
1934    png_size_t      size;            /* Size of the memory buffer. */
1935 
1936    unsigned int for_write       :1; /* Otherwise it is a read structure */
1937    unsigned int owned_file      :1; /* We own the file in io_ptr */
1938 } png_control;
1939 
1940 /* Return the pointer to the jmp_buf from a png_control: necessary because C
1941  * does not reveal the type of the elements of jmp_buf.
1942  */
1943 #ifdef __cplusplus
1944 #  define png_control_jmp_buf(pc) (((jmp_buf*)((pc)->error_buf))[0])
1945 #else
1946 #  define png_control_jmp_buf(pc) ((pc)->error_buf)
1947 #endif
1948 
1949 /* Utility to safely execute a piece of libpng code catching and logging any
1950  * errors that might occur.  Returns true on success, false on failure (either
1951  * of the function or as a result of a png_error.)
1952  */
1953 PNG_INTERNAL_FUNCTION(void,png_safe_error,(png_structp png_ptr,
1954    png_const_charp error_message),PNG_NORETURN);
1955 
1956 #ifdef PNG_WARNINGS_SUPPORTED
1957 PNG_INTERNAL_FUNCTION(void,png_safe_warning,(png_structp png_ptr,
1958    png_const_charp warning_message),PNG_EMPTY);
1959 #else
1960 #  define png_safe_warning 0/*dummy argument*/
1961 #endif
1962 
1963 PNG_INTERNAL_FUNCTION(int,png_safe_execute,(png_imagep image,
1964    int (*function)(png_voidp), png_voidp arg),PNG_EMPTY);
1965 
1966 /* Utility to log an error; this also cleans up the png_image; the function
1967  * always returns 0 (false).
1968  */
1969 PNG_INTERNAL_FUNCTION(int,png_image_error,(png_imagep image,
1970    png_const_charp error_message),PNG_EMPTY);
1971 
1972 #ifndef PNG_SIMPLIFIED_READ_SUPPORTED
1973 /* png_image_free is used by the write code but not exported */
1974 PNG_INTERNAL_FUNCTION(void, png_image_free, (png_imagep image), PNG_EMPTY);
1975 #endif /* !SIMPLIFIED_READ */
1976 
1977 #endif /* SIMPLIFIED READ/WRITE */
1978 
1979 /* These are initialization functions for hardware specific PNG filter
1980  * optimizations; list these here then select the appropriate one at compile
1981  * time using the macro PNG_FILTER_OPTIMIZATIONS.  If the macro is not defined
1982  * the generic code is used.
1983  */
1984 #ifdef PNG_FILTER_OPTIMIZATIONS
1985 PNG_INTERNAL_FUNCTION(void, PNG_FILTER_OPTIMIZATIONS, (png_structp png_ptr,
1986    unsigned int bpp), PNG_EMPTY);
1987    /* Just declare the optimization that will be used */
1988 #else
1989    /* List *all* the possible optimizations here - this branch is required if
1990     * the builder of libpng passes the definition of PNG_FILTER_OPTIMIZATIONS in
1991     * CFLAGS in place of CPPFLAGS *and* uses symbol prefixing.
1992     */
1993 PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_neon,
1994    (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
1995 #endif
1996 
1997 /* Maintainer: Put new private prototypes here ^ */
1998 
1999 #include "pngdebug.h"
2000 
2001 #ifdef __cplusplus
2002 }
2003 #endif
2004 
2005 #endif /* PNG_VERSION_INFO_ONLY */
2006 #endif /* PNGPRIV_H */
2007