Line data Source code
1 :
2 : /* png.c - location for general purpose libpng functions
3 : *
4 : * Last changed in libpng 1.6.29 [March 16, 2017]
5 : * Copyright (c) 1998-2002,2004,2006-2017 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 : * This code is released under the libpng license.
10 : * For conditions of distribution and use, see the disclaimer
11 : * and license in png.h
12 : */
13 :
14 : #include "pngpriv.h"
15 :
16 : /* Generate a compiler error if there is an old png.h in the search path. */
17 : typedef png_libpng_version_1_6_29 Your_png_h_is_not_version_1_6_29;
18 :
19 : /* Tells libpng that we have already handled the first "num_bytes" bytes
20 : * of the PNG file signature. If the PNG data is embedded into another
21 : * stream we can set num_bytes = 8 so that libpng will not attempt to read
22 : * or write any of the magic bytes before it starts on the IHDR.
23 : */
24 :
25 : #ifdef PNG_READ_SUPPORTED
26 : void PNGAPI
27 0 : png_set_sig_bytes(png_structrp png_ptr, int num_bytes)
28 : {
29 0 : unsigned int nb = (unsigned int)num_bytes;
30 :
31 : png_debug(1, "in png_set_sig_bytes");
32 :
33 0 : if (png_ptr == NULL)
34 0 : return;
35 :
36 0 : if (num_bytes < 0)
37 0 : nb = 0;
38 :
39 0 : if (nb > 8)
40 0 : png_error(png_ptr, "Too many bytes for PNG signature");
41 :
42 0 : png_ptr->sig_bytes = (png_byte)nb;
43 : }
44 :
45 : /* Checks whether the supplied bytes match the PNG signature. We allow
46 : * checking less than the full 8-byte signature so that those apps that
47 : * already read the first few bytes of a file to determine the file type
48 : * can simply check the remaining bytes for extra assurance. Returns
49 : * an integer less than, equal to, or greater than zero if sig is found,
50 : * respectively, to be less than, to match, or be greater than the correct
51 : * PNG signature (this is the same behavior as strcmp, memcmp, etc).
52 : */
53 : int PNGAPI
54 31 : png_sig_cmp(png_const_bytep sig, png_size_t start, png_size_t num_to_check)
55 : {
56 31 : png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
57 :
58 31 : if (num_to_check > 8)
59 0 : num_to_check = 8;
60 :
61 31 : else if (num_to_check < 1)
62 0 : return (-1);
63 :
64 31 : if (start > 7)
65 0 : return (-1);
66 :
67 31 : if (start + num_to_check > 8)
68 0 : num_to_check = 8 - start;
69 :
70 31 : return ((int)(memcmp(&sig[start], &png_signature[start], num_to_check)));
71 : }
72 :
73 : #endif /* READ */
74 :
75 : #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
76 : /* Function to allocate memory for zlib */
77 44 : PNG_FUNCTION(voidpf /* PRIVATE */,
78 : png_zalloc,(voidpf png_ptr, uInt items, uInt size),PNG_ALLOCATED)
79 : {
80 44 : png_alloc_size_t num_bytes = size;
81 :
82 44 : if (png_ptr == NULL)
83 0 : return NULL;
84 :
85 44 : if (items >= (~(png_alloc_size_t)0)/size)
86 : {
87 0 : png_warning (png_voidcast(png_structrp, png_ptr),
88 : "Potential overflow in png_zalloc()");
89 0 : return NULL;
90 : }
91 :
92 44 : num_bytes *= items;
93 44 : return png_malloc_warn(png_voidcast(png_structrp, png_ptr), num_bytes);
94 : }
95 :
96 : /* Function to free memory for zlib */
97 : void /* PRIVATE */
98 44 : png_zfree(voidpf png_ptr, voidpf ptr)
99 : {
100 44 : png_free(png_voidcast(png_const_structrp,png_ptr), ptr);
101 44 : }
102 :
103 : /* Reset the CRC variable to 32 bits of 1's. Care must be taken
104 : * in case CRC is > 32 bits to leave the top bits 0.
105 : */
106 : void /* PRIVATE */
107 206 : png_reset_crc(png_structrp png_ptr)
108 : {
109 : /* The cast is safe because the crc is a 32-bit value. */
110 206 : png_ptr->crc = (png_uint_32)crc32(0, Z_NULL, 0);
111 206 : }
112 :
113 : /* Calculate the CRC over a section of data. We can only pass as
114 : * much data to this routine as the largest single buffer size. We
115 : * also check that this data will actually be used before going to the
116 : * trouble of calculating it.
117 : */
118 : void /* PRIVATE */
119 561 : png_calculate_crc(png_structrp png_ptr, png_const_bytep ptr, png_size_t length)
120 : {
121 561 : int need_crc = 1;
122 :
123 561 : if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0)
124 : {
125 330 : if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
126 : (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
127 0 : need_crc = 0;
128 : }
129 :
130 : else /* critical */
131 : {
132 231 : if ((png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) != 0)
133 0 : need_crc = 0;
134 : }
135 :
136 : /* 'uLong' is defined in zlib.h as unsigned long; this means that on some
137 : * systems it is a 64-bit value. crc32, however, returns 32 bits so the
138 : * following cast is safe. 'uInt' may be no more than 16 bits, so it is
139 : * necessary to perform a loop here.
140 : */
141 561 : if (need_crc != 0 && length > 0)
142 : {
143 561 : uLong crc = png_ptr->crc; /* Should never issue a warning */
144 :
145 : do
146 : {
147 561 : uInt safe_length = (uInt)length;
148 : #ifndef __COVERITY__
149 561 : if (safe_length == 0)
150 0 : safe_length = (uInt)-1; /* evil, but safe */
151 : #endif
152 :
153 561 : crc = crc32(crc, ptr, safe_length);
154 :
155 : /* The following should never issue compiler warnings; if they do the
156 : * target system has characteristics that will probably violate other
157 : * assumptions within the libpng code.
158 : */
159 561 : ptr += safe_length;
160 561 : length -= safe_length;
161 : }
162 561 : while (length > 0);
163 :
164 : /* And the following is always safe because the crc is only 32 bits. */
165 561 : png_ptr->crc = (png_uint_32)crc;
166 : }
167 561 : }
168 :
169 : /* Check a user supplied version number, called from both read and write
170 : * functions that create a png_struct.
171 : */
172 : int
173 31 : png_user_version_check(png_structrp png_ptr, png_const_charp user_png_ver)
174 : {
175 : /* Libpng versions 1.0.0 and later are binary compatible if the version
176 : * string matches through the second '.'; we must recompile any
177 : * applications that use any older library version.
178 : */
179 :
180 31 : if (user_png_ver != NULL)
181 : {
182 31 : int i = -1;
183 31 : int found_dots = 0;
184 :
185 : do
186 : {
187 124 : i++;
188 124 : if (user_png_ver[i] != PNG_LIBPNG_VER_STRING[i])
189 0 : png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
190 124 : if (user_png_ver[i] == '.')
191 62 : found_dots++;
192 186 : } while (found_dots < 2 && user_png_ver[i] != 0 &&
193 217 : PNG_LIBPNG_VER_STRING[i] != 0);
194 : }
195 :
196 : else
197 0 : png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
198 :
199 31 : if ((png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH) != 0)
200 : {
201 : #ifdef PNG_WARNINGS_SUPPORTED
202 0 : size_t pos = 0;
203 : char m[128];
204 :
205 0 : pos = png_safecat(m, (sizeof m), pos,
206 : "Application built with libpng-");
207 0 : pos = png_safecat(m, (sizeof m), pos, user_png_ver);
208 0 : pos = png_safecat(m, (sizeof m), pos, " but running with ");
209 0 : pos = png_safecat(m, (sizeof m), pos, PNG_LIBPNG_VER_STRING);
210 : PNG_UNUSED(pos)
211 :
212 0 : png_warning(png_ptr, m);
213 : #endif
214 :
215 : #ifdef PNG_ERROR_NUMBERS_SUPPORTED
216 : png_ptr->flags = 0;
217 : #endif
218 :
219 0 : return 0;
220 : }
221 :
222 : /* Success return. */
223 31 : return 1;
224 : }
225 :
226 : /* Generic function to create a png_struct for either read or write - this
227 : * contains the common initialization.
228 : */
229 31 : PNG_FUNCTION(png_structp /* PRIVATE */,
230 : png_create_png_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
231 : png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
232 : png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
233 : {
234 : png_struct create_struct;
235 : # ifdef PNG_SETJMP_SUPPORTED
236 : jmp_buf create_jmp_buf;
237 : # endif
238 :
239 : /* This temporary stack-allocated structure is used to provide a place to
240 : * build enough context to allow the user provided memory allocator (if any)
241 : * to be called.
242 : */
243 31 : memset(&create_struct, 0, (sizeof create_struct));
244 :
245 : /* Added at libpng-1.2.6 */
246 : # ifdef PNG_USER_LIMITS_SUPPORTED
247 31 : create_struct.user_width_max = PNG_USER_WIDTH_MAX;
248 31 : create_struct.user_height_max = PNG_USER_HEIGHT_MAX;
249 :
250 : # ifdef PNG_USER_CHUNK_CACHE_MAX
251 : /* Added at libpng-1.2.43 and 1.4.0 */
252 31 : create_struct.user_chunk_cache_max = PNG_USER_CHUNK_CACHE_MAX;
253 : # endif
254 :
255 : # ifdef PNG_USER_CHUNK_MALLOC_MAX
256 : /* Added at libpng-1.2.43 and 1.4.1, required only for read but exists
257 : * in png_struct regardless.
258 : */
259 31 : create_struct.user_chunk_malloc_max = PNG_USER_CHUNK_MALLOC_MAX;
260 : # endif
261 : # endif
262 :
263 : /* The following two API calls simply set fields in png_struct, so it is safe
264 : * to do them now even though error handling is not yet set up.
265 : */
266 : # ifdef PNG_USER_MEM_SUPPORTED
267 : png_set_mem_fn(&create_struct, mem_ptr, malloc_fn, free_fn);
268 : # else
269 : PNG_UNUSED(mem_ptr)
270 : PNG_UNUSED(malloc_fn)
271 : PNG_UNUSED(free_fn)
272 : # endif
273 :
274 : /* (*error_fn) can return control to the caller after the error_ptr is set,
275 : * this will result in a memory leak unless the error_fn does something
276 : * extremely sophisticated. The design lacks merit but is implicit in the
277 : * API.
278 : */
279 31 : png_set_error_fn(&create_struct, error_ptr, error_fn, warn_fn);
280 :
281 : # ifdef PNG_SETJMP_SUPPORTED
282 31 : if (!setjmp(create_jmp_buf))
283 : # endif
284 : {
285 : # ifdef PNG_SETJMP_SUPPORTED
286 : /* Temporarily fake out the longjmp information until we have
287 : * successfully completed this function. This only works if we have
288 : * setjmp() support compiled in, but it is safe - this stuff should
289 : * never happen.
290 : */
291 31 : create_struct.jmp_buf_ptr = &create_jmp_buf;
292 31 : create_struct.jmp_buf_size = 0; /*stack allocation*/
293 31 : create_struct.longjmp_fn = longjmp;
294 : # endif
295 : /* Call the general version checker (shared with read and write code):
296 : */
297 31 : if (png_user_version_check(&create_struct, user_png_ver) != 0)
298 : {
299 31 : png_structrp png_ptr = png_voidcast(png_structrp,
300 : png_malloc_warn(&create_struct, (sizeof *png_ptr)));
301 :
302 31 : if (png_ptr != NULL)
303 : {
304 : /* png_ptr->zstream holds a back-pointer to the png_struct, so
305 : * this can only be done now:
306 : */
307 31 : create_struct.zstream.zalloc = png_zalloc;
308 31 : create_struct.zstream.zfree = png_zfree;
309 31 : create_struct.zstream.opaque = png_ptr;
310 :
311 : # ifdef PNG_SETJMP_SUPPORTED
312 : /* Eliminate the local error handling: */
313 31 : create_struct.jmp_buf_ptr = NULL;
314 31 : create_struct.jmp_buf_size = 0;
315 31 : create_struct.longjmp_fn = 0;
316 : # endif
317 :
318 31 : *png_ptr = create_struct;
319 :
320 : /* This is the successful return point */
321 31 : return png_ptr;
322 : }
323 : }
324 : }
325 :
326 : /* A longjmp because of a bug in the application storage allocator or a
327 : * simple failure to allocate the png_struct.
328 : */
329 0 : return NULL;
330 : }
331 :
332 : /* Allocate the memory for an info_struct for the application. */
333 31 : PNG_FUNCTION(png_infop,PNGAPI
334 : png_create_info_struct,(png_const_structrp png_ptr),PNG_ALLOCATED)
335 : {
336 : png_inforp info_ptr;
337 :
338 : png_debug(1, "in png_create_info_struct");
339 :
340 31 : if (png_ptr == NULL)
341 0 : return NULL;
342 :
343 : /* Use the internal API that does not (or at least should not) error out, so
344 : * that this call always returns ok. The application typically sets up the
345 : * error handling *after* creating the info_struct because this is the way it
346 : * has always been done in 'example.c'.
347 : */
348 31 : info_ptr = png_voidcast(png_inforp, png_malloc_base(png_ptr,
349 : (sizeof *info_ptr)));
350 :
351 31 : if (info_ptr != NULL)
352 31 : memset(info_ptr, 0, (sizeof *info_ptr));
353 :
354 31 : return info_ptr;
355 : }
356 :
357 : /* This function frees the memory associated with a single info struct.
358 : * Normally, one would use either png_destroy_read_struct() or
359 : * png_destroy_write_struct() to free an info struct, but this may be
360 : * useful for some applications. From libpng 1.6.0 this function is also used
361 : * internally to implement the png_info release part of the 'struct' destroy
362 : * APIs. This ensures that all possible approaches free the same data (all of
363 : * it).
364 : */
365 : void PNGAPI
366 62 : png_destroy_info_struct(png_const_structrp png_ptr, png_infopp info_ptr_ptr)
367 : {
368 62 : png_inforp info_ptr = NULL;
369 :
370 : png_debug(1, "in png_destroy_info_struct");
371 :
372 62 : if (png_ptr == NULL)
373 0 : return;
374 :
375 62 : if (info_ptr_ptr != NULL)
376 31 : info_ptr = *info_ptr_ptr;
377 :
378 62 : if (info_ptr != NULL)
379 : {
380 : /* Do this first in case of an error below; if the app implements its own
381 : * memory management this can lead to png_free calling png_error, which
382 : * will abort this routine and return control to the app error handler.
383 : * An infinite loop may result if it then tries to free the same info
384 : * ptr.
385 : */
386 31 : *info_ptr_ptr = NULL;
387 :
388 31 : png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
389 31 : memset(info_ptr, 0, (sizeof *info_ptr));
390 31 : png_free(png_ptr, info_ptr);
391 : }
392 : }
393 :
394 : /* Initialize the info structure. This is now an internal function (0.89)
395 : * and applications using it are urged to use png_create_info_struct()
396 : * instead. Use deprecated in 1.6.0, internal use removed (used internally it
397 : * is just a memset).
398 : *
399 : * NOTE: it is almost inconceivable that this API is used because it bypasses
400 : * the user-memory mechanism and the user error handling/warning mechanisms in
401 : * those cases where it does anything other than a memset.
402 : */
403 0 : PNG_FUNCTION(void,PNGAPI
404 : png_info_init_3,(png_infopp ptr_ptr, png_size_t png_info_struct_size),
405 : PNG_DEPRECATED)
406 : {
407 0 : png_inforp info_ptr = *ptr_ptr;
408 :
409 : png_debug(1, "in png_info_init_3");
410 :
411 0 : if (info_ptr == NULL)
412 0 : return;
413 :
414 0 : if ((sizeof (png_info)) > png_info_struct_size)
415 : {
416 0 : *ptr_ptr = NULL;
417 : /* The following line is why this API should not be used: */
418 0 : free(info_ptr);
419 0 : info_ptr = png_voidcast(png_inforp, png_malloc_base(NULL,
420 : (sizeof *info_ptr)));
421 0 : if (info_ptr == NULL)
422 0 : return;
423 0 : *ptr_ptr = info_ptr;
424 : }
425 :
426 : /* Set everything to 0 */
427 0 : memset(info_ptr, 0, (sizeof *info_ptr));
428 : }
429 :
430 : /* The following API is not called internally */
431 : void PNGAPI
432 0 : png_data_freer(png_const_structrp png_ptr, png_inforp info_ptr,
433 : int freer, png_uint_32 mask)
434 : {
435 : png_debug(1, "in png_data_freer");
436 :
437 0 : if (png_ptr == NULL || info_ptr == NULL)
438 0 : return;
439 :
440 0 : if (freer == PNG_DESTROY_WILL_FREE_DATA)
441 0 : info_ptr->free_me |= mask;
442 :
443 0 : else if (freer == PNG_USER_WILL_FREE_DATA)
444 0 : info_ptr->free_me &= ~mask;
445 :
446 : else
447 0 : png_error(png_ptr, "Unknown freer parameter in png_data_freer");
448 : }
449 :
450 : void PNGAPI
451 35 : png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask,
452 : int num)
453 : {
454 : png_debug(1, "in png_free_data");
455 :
456 35 : if (png_ptr == NULL || info_ptr == NULL)
457 0 : return;
458 :
459 : #ifdef PNG_TEXT_SUPPORTED
460 : /* Free text item num or (if num == -1) all text items */
461 : if (info_ptr->text != NULL &&
462 : ((mask & PNG_FREE_TEXT) & info_ptr->free_me) != 0)
463 : {
464 : if (num != -1)
465 : {
466 : png_free(png_ptr, info_ptr->text[num].key);
467 : info_ptr->text[num].key = NULL;
468 : }
469 :
470 : else
471 : {
472 : int i;
473 :
474 : for (i = 0; i < info_ptr->num_text; i++)
475 : png_free(png_ptr, info_ptr->text[i].key);
476 :
477 : png_free(png_ptr, info_ptr->text);
478 : info_ptr->text = NULL;
479 : info_ptr->num_text = 0;
480 : info_ptr->max_text = 0;
481 : }
482 : }
483 : #endif
484 :
485 : #ifdef PNG_tRNS_SUPPORTED
486 : /* Free any tRNS entry */
487 35 : if (((mask & PNG_FREE_TRNS) & info_ptr->free_me) != 0)
488 : {
489 2 : info_ptr->valid &= ~PNG_INFO_tRNS;
490 2 : png_free(png_ptr, info_ptr->trans_alpha);
491 2 : info_ptr->trans_alpha = NULL;
492 2 : info_ptr->num_trans = 0;
493 : }
494 : #endif
495 :
496 : #ifdef PNG_sCAL_SUPPORTED
497 : /* Free any sCAL entry */
498 : if (((mask & PNG_FREE_SCAL) & info_ptr->free_me) != 0)
499 : {
500 : png_free(png_ptr, info_ptr->scal_s_width);
501 : png_free(png_ptr, info_ptr->scal_s_height);
502 : info_ptr->scal_s_width = NULL;
503 : info_ptr->scal_s_height = NULL;
504 : info_ptr->valid &= ~PNG_INFO_sCAL;
505 : }
506 : #endif
507 :
508 : #ifdef PNG_pCAL_SUPPORTED
509 : /* Free any pCAL entry */
510 : if (((mask & PNG_FREE_PCAL) & info_ptr->free_me) != 0)
511 : {
512 : png_free(png_ptr, info_ptr->pcal_purpose);
513 : png_free(png_ptr, info_ptr->pcal_units);
514 : info_ptr->pcal_purpose = NULL;
515 : info_ptr->pcal_units = NULL;
516 :
517 : if (info_ptr->pcal_params != NULL)
518 : {
519 : int i;
520 :
521 : for (i = 0; i < info_ptr->pcal_nparams; i++)
522 : png_free(png_ptr, info_ptr->pcal_params[i]);
523 :
524 : png_free(png_ptr, info_ptr->pcal_params);
525 : info_ptr->pcal_params = NULL;
526 : }
527 : info_ptr->valid &= ~PNG_INFO_pCAL;
528 : }
529 : #endif
530 :
531 : #ifdef PNG_iCCP_SUPPORTED
532 : /* Free any profile entry */
533 35 : if (((mask & PNG_FREE_ICCP) & info_ptr->free_me) != 0)
534 : {
535 0 : png_free(png_ptr, info_ptr->iccp_name);
536 0 : png_free(png_ptr, info_ptr->iccp_profile);
537 0 : info_ptr->iccp_name = NULL;
538 0 : info_ptr->iccp_profile = NULL;
539 0 : info_ptr->valid &= ~PNG_INFO_iCCP;
540 : }
541 : #endif
542 :
543 : #ifdef PNG_sPLT_SUPPORTED
544 : /* Free a given sPLT entry, or (if num == -1) all sPLT entries */
545 : if (info_ptr->splt_palettes != NULL &&
546 : ((mask & PNG_FREE_SPLT) & info_ptr->free_me) != 0)
547 : {
548 : if (num != -1)
549 : {
550 : png_free(png_ptr, info_ptr->splt_palettes[num].name);
551 : png_free(png_ptr, info_ptr->splt_palettes[num].entries);
552 : info_ptr->splt_palettes[num].name = NULL;
553 : info_ptr->splt_palettes[num].entries = NULL;
554 : }
555 :
556 : else
557 : {
558 : int i;
559 :
560 : for (i = 0; i < info_ptr->splt_palettes_num; i++)
561 : {
562 : png_free(png_ptr, info_ptr->splt_palettes[i].name);
563 : png_free(png_ptr, info_ptr->splt_palettes[i].entries);
564 : }
565 :
566 : png_free(png_ptr, info_ptr->splt_palettes);
567 : info_ptr->splt_palettes = NULL;
568 : info_ptr->splt_palettes_num = 0;
569 : info_ptr->valid &= ~PNG_INFO_sPLT;
570 : }
571 : }
572 : #endif
573 :
574 : #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
575 : if (info_ptr->unknown_chunks != NULL &&
576 : ((mask & PNG_FREE_UNKN) & info_ptr->free_me) != 0)
577 : {
578 : if (num != -1)
579 : {
580 : png_free(png_ptr, info_ptr->unknown_chunks[num].data);
581 : info_ptr->unknown_chunks[num].data = NULL;
582 : }
583 :
584 : else
585 : {
586 : int i;
587 :
588 : for (i = 0; i < info_ptr->unknown_chunks_num; i++)
589 : png_free(png_ptr, info_ptr->unknown_chunks[i].data);
590 :
591 : png_free(png_ptr, info_ptr->unknown_chunks);
592 : info_ptr->unknown_chunks = NULL;
593 : info_ptr->unknown_chunks_num = 0;
594 : }
595 : }
596 : #endif
597 :
598 : #ifdef PNG_hIST_SUPPORTED
599 : /* Free any hIST entry */
600 : if (((mask & PNG_FREE_HIST) & info_ptr->free_me) != 0)
601 : {
602 : png_free(png_ptr, info_ptr->hist);
603 : info_ptr->hist = NULL;
604 : info_ptr->valid &= ~PNG_INFO_hIST;
605 : }
606 : #endif
607 :
608 : /* Free any PLTE entry that was internally allocated */
609 35 : if (((mask & PNG_FREE_PLTE) & info_ptr->free_me) != 0)
610 : {
611 2 : png_free(png_ptr, info_ptr->palette);
612 2 : info_ptr->palette = NULL;
613 2 : info_ptr->valid &= ~PNG_INFO_PLTE;
614 2 : info_ptr->num_palette = 0;
615 : }
616 :
617 : #ifdef PNG_INFO_IMAGE_SUPPORTED
618 : /* Free any image bits attached to the info structure */
619 : if (((mask & PNG_FREE_ROWS) & info_ptr->free_me) != 0)
620 : {
621 : if (info_ptr->row_pointers != NULL)
622 : {
623 : png_uint_32 row;
624 : for (row = 0; row < info_ptr->height; row++)
625 : png_free(png_ptr, info_ptr->row_pointers[row]);
626 :
627 : png_free(png_ptr, info_ptr->row_pointers);
628 : info_ptr->row_pointers = NULL;
629 : }
630 : info_ptr->valid &= ~PNG_INFO_IDAT;
631 : }
632 : #endif
633 :
634 35 : if (num != -1)
635 4 : mask &= ~PNG_FREE_MUL;
636 :
637 35 : info_ptr->free_me &= ~mask;
638 : }
639 : #endif /* READ || WRITE */
640 :
641 : /* This function returns a pointer to the io_ptr associated with the user
642 : * functions. The application should free any memory associated with this
643 : * pointer before png_write_destroy() or png_read_destroy() are called.
644 : */
645 : png_voidp PNGAPI
646 0 : png_get_io_ptr(png_const_structrp png_ptr)
647 : {
648 0 : if (png_ptr == NULL)
649 0 : return (NULL);
650 :
651 0 : return (png_ptr->io_ptr);
652 : }
653 :
654 : #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
655 : # ifdef PNG_STDIO_SUPPORTED
656 : /* Initialize the default input/output functions for the PNG file. If you
657 : * use your own read or write routines, you can call either png_set_read_fn()
658 : * or png_set_write_fn() instead of png_init_io(). If you have defined
659 : * PNG_NO_STDIO or otherwise disabled PNG_STDIO_SUPPORTED, you must use a
660 : * function of your own because "FILE *" isn't necessarily available.
661 : */
662 : void PNGAPI
663 0 : png_init_io(png_structrp png_ptr, png_FILE_p fp)
664 : {
665 : png_debug(1, "in png_init_io");
666 :
667 0 : if (png_ptr == NULL)
668 0 : return;
669 :
670 0 : png_ptr->io_ptr = (png_voidp)fp;
671 : }
672 : # endif
673 :
674 : # ifdef PNG_SAVE_INT_32_SUPPORTED
675 : /* PNG signed integers are saved in 32-bit 2's complement format. ANSI C-90
676 : * defines a cast of a signed integer to an unsigned integer either to preserve
677 : * the value, if it is positive, or to calculate:
678 : *
679 : * (UNSIGNED_MAX+1) + integer
680 : *
681 : * Where UNSIGNED_MAX is the appropriate maximum unsigned value, so when the
682 : * negative integral value is added the result will be an unsigned value
683 : * correspnding to the 2's complement representation.
684 : */
685 : void PNGAPI
686 : png_save_int_32(png_bytep buf, png_int_32 i)
687 : {
688 : png_save_uint_32(buf, (png_uint_32)i);
689 : }
690 : # endif
691 :
692 : # ifdef PNG_TIME_RFC1123_SUPPORTED
693 : /* Convert the supplied time into an RFC 1123 string suitable for use in
694 : * a "Creation Time" or other text-based time string.
695 : */
696 : int PNGAPI
697 : png_convert_to_rfc1123_buffer(char out[29], png_const_timep ptime)
698 : {
699 : static PNG_CONST char short_months[12][4] =
700 : {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
701 : "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
702 :
703 : if (out == NULL)
704 : return 0;
705 :
706 : if (ptime->year > 9999 /* RFC1123 limitation */ ||
707 : ptime->month == 0 || ptime->month > 12 ||
708 : ptime->day == 0 || ptime->day > 31 ||
709 : ptime->hour > 23 || ptime->minute > 59 ||
710 : ptime->second > 60)
711 : return 0;
712 :
713 : {
714 : size_t pos = 0;
715 : char number_buf[5]; /* enough for a four-digit year */
716 :
717 : # define APPEND_STRING(string) pos = png_safecat(out, 29, pos, (string))
718 : # define APPEND_NUMBER(format, value)\
719 : APPEND_STRING(PNG_FORMAT_NUMBER(number_buf, format, (value)))
720 : # define APPEND(ch) if (pos < 28) out[pos++] = (ch)
721 :
722 : APPEND_NUMBER(PNG_NUMBER_FORMAT_u, (unsigned)ptime->day);
723 : APPEND(' ');
724 : APPEND_STRING(short_months[(ptime->month - 1)]);
725 : APPEND(' ');
726 : APPEND_NUMBER(PNG_NUMBER_FORMAT_u, ptime->year);
727 : APPEND(' ');
728 : APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->hour);
729 : APPEND(':');
730 : APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->minute);
731 : APPEND(':');
732 : APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->second);
733 : APPEND_STRING(" +0000"); /* This reliably terminates the buffer */
734 : PNG_UNUSED (pos)
735 :
736 : # undef APPEND
737 : # undef APPEND_NUMBER
738 : # undef APPEND_STRING
739 : }
740 :
741 : return 1;
742 : }
743 :
744 : # if PNG_LIBPNG_VER < 10700
745 : /* To do: remove the following from libpng-1.7 */
746 : /* Original API that uses a private buffer in png_struct.
747 : * Deprecated because it causes png_struct to carry a spurious temporary
748 : * buffer (png_struct::time_buffer), better to have the caller pass this in.
749 : */
750 : png_const_charp PNGAPI
751 : png_convert_to_rfc1123(png_structrp png_ptr, png_const_timep ptime)
752 : {
753 : if (png_ptr != NULL)
754 : {
755 : /* The only failure above if png_ptr != NULL is from an invalid ptime */
756 : if (png_convert_to_rfc1123_buffer(png_ptr->time_buffer, ptime) == 0)
757 : png_warning(png_ptr, "Ignoring invalid time value");
758 :
759 : else
760 : return png_ptr->time_buffer;
761 : }
762 :
763 : return NULL;
764 : }
765 : # endif /* LIBPNG_VER < 10700 */
766 : # endif /* TIME_RFC1123 */
767 :
768 : #endif /* READ || WRITE */
769 :
770 : png_const_charp PNGAPI
771 0 : png_get_copyright(png_const_structrp png_ptr)
772 : {
773 : PNG_UNUSED(png_ptr) /* Silence compiler warning about unused png_ptr */
774 : #ifdef PNG_STRING_COPYRIGHT
775 : return PNG_STRING_COPYRIGHT
776 : #else
777 : # ifdef __STDC__
778 0 : return PNG_STRING_NEWLINE \
779 : "libpng version 1.6.29+apng - March 16, 2017" PNG_STRING_NEWLINE \
780 : "Copyright (c) 1998-2002,2004,2006-2017 Glenn Randers-Pehrson" \
781 : PNG_STRING_NEWLINE \
782 : "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \
783 : "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \
784 : PNG_STRING_NEWLINE \
785 : "Portions Copyright (c) 2006-2007 Andrew Smith" PNG_STRING_NEWLINE \
786 : "Portions Copyright (c) 2008-2017 Max Stepin" PNG_STRING_NEWLINE ;
787 : # else
788 : return "libpng version 1.6.29+apng - March 16, 2017\
789 : Copyright (c) 1998-2002,2004,2006-2017 Glenn Randers-Pehrson\
790 : Copyright (c) 1996-1997 Andreas Dilger\
791 : Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.\
792 : Portions Copyright (c) 2006-2007 Andrew Smith\
793 : Portions Copyright (c) 2008-2017 Max Stepin";
794 : # endif
795 : #endif
796 : }
797 :
798 : /* The following return the library version as a short string in the
799 : * format 1.0.0 through 99.99.99zz. To get the version of *.h files
800 : * used with your application, print out PNG_LIBPNG_VER_STRING, which
801 : * is defined in png.h.
802 : * Note: now there is no difference between png_get_libpng_ver() and
803 : * png_get_header_ver(). Due to the version_nn_nn_nn typedef guard,
804 : * it is guaranteed that png.c uses the correct version of png.h.
805 : */
806 : png_const_charp PNGAPI
807 0 : png_get_libpng_ver(png_const_structrp png_ptr)
808 : {
809 : /* Version of *.c files used when building libpng */
810 0 : return png_get_header_ver(png_ptr);
811 : }
812 :
813 : png_const_charp PNGAPI
814 0 : png_get_header_ver(png_const_structrp png_ptr)
815 : {
816 : /* Version of *.h files used when building libpng */
817 : PNG_UNUSED(png_ptr) /* Silence compiler warning about unused png_ptr */
818 0 : return PNG_LIBPNG_VER_STRING;
819 : }
820 :
821 : png_const_charp PNGAPI
822 0 : png_get_header_version(png_const_structrp png_ptr)
823 : {
824 : /* Returns longer string containing both version and date */
825 : PNG_UNUSED(png_ptr) /* Silence compiler warning about unused png_ptr */
826 : #ifdef __STDC__
827 0 : return PNG_HEADER_VERSION_STRING
828 : # ifndef PNG_READ_SUPPORTED
829 : " (NO READ SUPPORT)"
830 : # endif
831 : PNG_STRING_NEWLINE;
832 : #else
833 : return PNG_HEADER_VERSION_STRING;
834 : #endif
835 : }
836 :
837 : #ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
838 : /* NOTE: this routine is not used internally! */
839 : /* Build a grayscale palette. Palette is assumed to be 1 << bit_depth
840 : * large of png_color. This lets grayscale images be treated as
841 : * paletted. Most useful for gamma correction and simplification
842 : * of code. This API is not used internally.
843 : */
844 : void PNGAPI
845 : png_build_grayscale_palette(int bit_depth, png_colorp palette)
846 : {
847 : int num_palette;
848 : int color_inc;
849 : int i;
850 : int v;
851 :
852 : png_debug(1, "in png_do_build_grayscale_palette");
853 :
854 : if (palette == NULL)
855 : return;
856 :
857 : switch (bit_depth)
858 : {
859 : case 1:
860 : num_palette = 2;
861 : color_inc = 0xff;
862 : break;
863 :
864 : case 2:
865 : num_palette = 4;
866 : color_inc = 0x55;
867 : break;
868 :
869 : case 4:
870 : num_palette = 16;
871 : color_inc = 0x11;
872 : break;
873 :
874 : case 8:
875 : num_palette = 256;
876 : color_inc = 1;
877 : break;
878 :
879 : default:
880 : num_palette = 0;
881 : color_inc = 0;
882 : break;
883 : }
884 :
885 : for (i = 0, v = 0; i < num_palette; i++, v += color_inc)
886 : {
887 : palette[i].red = (png_byte)(v & 0xff);
888 : palette[i].green = (png_byte)(v & 0xff);
889 : palette[i].blue = (png_byte)(v & 0xff);
890 : }
891 : }
892 : #endif
893 :
894 : #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
895 : int PNGAPI
896 : png_handle_as_unknown(png_const_structrp png_ptr, png_const_bytep chunk_name)
897 : {
898 : /* Check chunk_name and return "keep" value if it's on the list, else 0 */
899 : png_const_bytep p, p_end;
900 :
901 : if (png_ptr == NULL || chunk_name == NULL || png_ptr->num_chunk_list == 0)
902 : return PNG_HANDLE_CHUNK_AS_DEFAULT;
903 :
904 : p_end = png_ptr->chunk_list;
905 : p = p_end + png_ptr->num_chunk_list*5; /* beyond end */
906 :
907 : /* The code is the fifth byte after each four byte string. Historically this
908 : * code was always searched from the end of the list, this is no longer
909 : * necessary because the 'set' routine handles duplicate entries correcty.
910 : */
911 : do /* num_chunk_list > 0, so at least one */
912 : {
913 : p -= 5;
914 :
915 : if (memcmp(chunk_name, p, 4) == 0)
916 : return p[4];
917 : }
918 : while (p > p_end);
919 :
920 : /* This means that known chunks should be processed and unknown chunks should
921 : * be handled according to the value of png_ptr->unknown_default; this can be
922 : * confusing because, as a result, there are two levels of defaulting for
923 : * unknown chunks.
924 : */
925 : return PNG_HANDLE_CHUNK_AS_DEFAULT;
926 : }
927 :
928 : #if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) ||\
929 : defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
930 : int /* PRIVATE */
931 : png_chunk_unknown_handling(png_const_structrp png_ptr, png_uint_32 chunk_name)
932 : {
933 : png_byte chunk_string[5];
934 :
935 : PNG_CSTRING_FROM_CHUNK(chunk_string, chunk_name);
936 : return png_handle_as_unknown(png_ptr, chunk_string);
937 : }
938 : #endif /* READ_UNKNOWN_CHUNKS || HANDLE_AS_UNKNOWN */
939 : #endif /* SET_UNKNOWN_CHUNKS */
940 :
941 : #ifdef PNG_READ_SUPPORTED
942 : /* This function, added to libpng-1.0.6g, is untested. */
943 : int PNGAPI
944 0 : png_reset_zstream(png_structrp png_ptr)
945 : {
946 0 : if (png_ptr == NULL)
947 0 : return Z_STREAM_ERROR;
948 :
949 : /* WARNING: this resets the window bits to the maximum! */
950 0 : return (inflateReset(&png_ptr->zstream));
951 : }
952 : #endif /* READ */
953 :
954 : /* This function was added to libpng-1.0.7 */
955 : png_uint_32 PNGAPI
956 0 : png_access_version_number(void)
957 : {
958 : /* Version of *.c files used when building libpng */
959 0 : return((png_uint_32)PNG_LIBPNG_VER);
960 : }
961 :
962 : #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
963 : /* Ensure that png_ptr->zstream.msg holds some appropriate error message string.
964 : * If it doesn't 'ret' is used to set it to something appropriate, even in cases
965 : * like Z_OK or Z_STREAM_END where the error code is apparently a success code.
966 : */
967 : void /* PRIVATE */
968 0 : png_zstream_error(png_structrp png_ptr, int ret)
969 : {
970 : /* Translate 'ret' into an appropriate error string, priority is given to the
971 : * one in zstream if set. This always returns a string, even in cases like
972 : * Z_OK or Z_STREAM_END where the error code is a success code.
973 : */
974 0 : if (png_ptr->zstream.msg == NULL) switch (ret)
975 : {
976 : default:
977 : case Z_OK:
978 0 : png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected zlib return code");
979 0 : break;
980 :
981 : case Z_STREAM_END:
982 : /* Normal exit */
983 0 : png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected end of LZ stream");
984 0 : break;
985 :
986 : case Z_NEED_DICT:
987 : /* This means the deflate stream did not have a dictionary; this
988 : * indicates a bogus PNG.
989 : */
990 0 : png_ptr->zstream.msg = PNGZ_MSG_CAST("missing LZ dictionary");
991 0 : break;
992 :
993 : case Z_ERRNO:
994 : /* gz APIs only: should not happen */
995 0 : png_ptr->zstream.msg = PNGZ_MSG_CAST("zlib IO error");
996 0 : break;
997 :
998 : case Z_STREAM_ERROR:
999 : /* internal libpng error */
1000 0 : png_ptr->zstream.msg = PNGZ_MSG_CAST("bad parameters to zlib");
1001 0 : break;
1002 :
1003 : case Z_DATA_ERROR:
1004 0 : png_ptr->zstream.msg = PNGZ_MSG_CAST("damaged LZ stream");
1005 0 : break;
1006 :
1007 : case Z_MEM_ERROR:
1008 0 : png_ptr->zstream.msg = PNGZ_MSG_CAST("insufficient memory");
1009 0 : break;
1010 :
1011 : case Z_BUF_ERROR:
1012 : /* End of input or output; not a problem if the caller is doing
1013 : * incremental read or write.
1014 : */
1015 0 : png_ptr->zstream.msg = PNGZ_MSG_CAST("truncated");
1016 0 : break;
1017 :
1018 : case Z_VERSION_ERROR:
1019 0 : png_ptr->zstream.msg = PNGZ_MSG_CAST("unsupported zlib version");
1020 0 : break;
1021 :
1022 : case PNG_UNEXPECTED_ZLIB_RETURN:
1023 : /* Compile errors here mean that zlib now uses the value co-opted in
1024 : * pngpriv.h for PNG_UNEXPECTED_ZLIB_RETURN; update the switch above
1025 : * and change pngpriv.h. Note that this message is "... return",
1026 : * whereas the default/Z_OK one is "... return code".
1027 : */
1028 0 : png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected zlib return");
1029 0 : break;
1030 : }
1031 0 : }
1032 :
1033 : /* png_convert_size: a PNGAPI but no longer in png.h, so deleted
1034 : * at libpng 1.5.5!
1035 : */
1036 :
1037 : /* Added at libpng version 1.2.34 and 1.4.0 (moved from pngset.c) */
1038 : #ifdef PNG_GAMMA_SUPPORTED /* always set if COLORSPACE */
1039 : static int
1040 8 : png_colorspace_check_gamma(png_const_structrp png_ptr,
1041 : png_colorspacerp colorspace, png_fixed_point gAMA, int from)
1042 : /* This is called to check a new gamma value against an existing one. The
1043 : * routine returns false if the new gamma value should not be written.
1044 : *
1045 : * 'from' says where the new gamma value comes from:
1046 : *
1047 : * 0: the new gamma value is the libpng estimate for an ICC profile
1048 : * 1: the new gamma value comes from a gAMA chunk
1049 : * 2: the new gamma value comes from an sRGB chunk
1050 : */
1051 : {
1052 : png_fixed_point gtest;
1053 :
1054 8 : if ((colorspace->flags & PNG_COLORSPACE_HAVE_GAMMA) != 0 &&
1055 0 : (png_muldiv(>est, colorspace->gamma, PNG_FP_1, gAMA) == 0 ||
1056 0 : png_gamma_significant(gtest) != 0))
1057 : {
1058 : /* Either this is an sRGB image, in which case the calculated gamma
1059 : * approximation should match, or this is an image with a profile and the
1060 : * value libpng calculates for the gamma of the profile does not match the
1061 : * value recorded in the file. The former, sRGB, case is an error, the
1062 : * latter is just a warning.
1063 : */
1064 0 : if ((colorspace->flags & PNG_COLORSPACE_FROM_sRGB) != 0 || from == 2)
1065 : {
1066 0 : png_chunk_report(png_ptr, "gamma value does not match sRGB",
1067 : PNG_CHUNK_ERROR);
1068 : /* Do not overwrite an sRGB value */
1069 0 : return from == 2;
1070 : }
1071 :
1072 : else /* sRGB tag not involved */
1073 : {
1074 0 : png_chunk_report(png_ptr, "gamma value does not match libpng estimate",
1075 : PNG_CHUNK_WARNING);
1076 0 : return from == 1;
1077 : }
1078 : }
1079 :
1080 8 : return 1;
1081 : }
1082 :
1083 : void /* PRIVATE */
1084 0 : png_colorspace_set_gamma(png_const_structrp png_ptr,
1085 : png_colorspacerp colorspace, png_fixed_point gAMA)
1086 : {
1087 : /* Changed in libpng-1.5.4 to limit the values to ensure overflow can't
1088 : * occur. Since the fixed point representation is asymetrical it is
1089 : * possible for 1/gamma to overflow the limit of 21474 and this means the
1090 : * gamma value must be at least 5/100000 and hence at most 20000.0. For
1091 : * safety the limits here are a little narrower. The values are 0.00016 to
1092 : * 6250.0, which are truly ridiculous gamma values (and will produce
1093 : * displays that are all black or all white.)
1094 : *
1095 : * In 1.6.0 this test replaces the ones in pngrutil.c, in the gAMA chunk
1096 : * handling code, which only required the value to be >0.
1097 : */
1098 : png_const_charp errmsg;
1099 :
1100 0 : if (gAMA < 16 || gAMA > 625000000)
1101 0 : errmsg = "gamma value out of range";
1102 :
1103 : # ifdef PNG_READ_gAMA_SUPPORTED
1104 : /* Allow the application to set the gamma value more than once */
1105 0 : else if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 &&
1106 0 : (colorspace->flags & PNG_COLORSPACE_FROM_gAMA) != 0)
1107 0 : errmsg = "duplicate";
1108 : # endif
1109 :
1110 : /* Do nothing if the colorspace is already invalid */
1111 0 : else if ((colorspace->flags & PNG_COLORSPACE_INVALID) != 0)
1112 0 : return;
1113 :
1114 : else
1115 : {
1116 0 : if (png_colorspace_check_gamma(png_ptr, colorspace, gAMA,
1117 : 1/*from gAMA*/) != 0)
1118 : {
1119 : /* Store this gamma value. */
1120 0 : colorspace->gamma = gAMA;
1121 0 : colorspace->flags |=
1122 : (PNG_COLORSPACE_HAVE_GAMMA | PNG_COLORSPACE_FROM_gAMA);
1123 : }
1124 :
1125 : /* At present if the check_gamma test fails the gamma of the colorspace is
1126 : * not updated however the colorspace is not invalidated. This
1127 : * corresponds to the case where the existing gamma comes from an sRGB
1128 : * chunk or profile. An error message has already been output.
1129 : */
1130 0 : return;
1131 : }
1132 :
1133 : /* Error exit - errmsg has been set. */
1134 0 : colorspace->flags |= PNG_COLORSPACE_INVALID;
1135 0 : png_chunk_report(png_ptr, errmsg, PNG_CHUNK_WRITE_ERROR);
1136 : }
1137 :
1138 : void /* PRIVATE */
1139 8 : png_colorspace_sync_info(png_const_structrp png_ptr, png_inforp info_ptr)
1140 : {
1141 8 : if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
1142 : {
1143 : /* Everything is invalid */
1144 0 : info_ptr->valid &= ~(PNG_INFO_gAMA|PNG_INFO_cHRM|PNG_INFO_sRGB|
1145 : PNG_INFO_iCCP);
1146 :
1147 : # ifdef PNG_COLORSPACE_SUPPORTED
1148 : /* Clean up the iCCP profile now if it won't be used. */
1149 0 : png_free_data(png_ptr, info_ptr, PNG_FREE_ICCP, -1/*not used*/);
1150 : # else
1151 : PNG_UNUSED(png_ptr)
1152 : # endif
1153 : }
1154 :
1155 : else
1156 : {
1157 : # ifdef PNG_COLORSPACE_SUPPORTED
1158 : /* Leave the INFO_iCCP flag set if the pngset.c code has already set
1159 : * it; this allows a PNG to contain a profile which matches sRGB and
1160 : * yet still have that profile retrievable by the application.
1161 : */
1162 8 : if ((info_ptr->colorspace.flags & PNG_COLORSPACE_MATCHES_sRGB) != 0)
1163 8 : info_ptr->valid |= PNG_INFO_sRGB;
1164 :
1165 : else
1166 0 : info_ptr->valid &= ~PNG_INFO_sRGB;
1167 :
1168 8 : if ((info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
1169 8 : info_ptr->valid |= PNG_INFO_cHRM;
1170 :
1171 : else
1172 0 : info_ptr->valid &= ~PNG_INFO_cHRM;
1173 : # endif
1174 :
1175 8 : if ((info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) != 0)
1176 8 : info_ptr->valid |= PNG_INFO_gAMA;
1177 :
1178 : else
1179 0 : info_ptr->valid &= ~PNG_INFO_gAMA;
1180 : }
1181 8 : }
1182 :
1183 : #ifdef PNG_READ_SUPPORTED
1184 : void /* PRIVATE */
1185 8 : png_colorspace_sync(png_const_structrp png_ptr, png_inforp info_ptr)
1186 : {
1187 8 : if (info_ptr == NULL) /* reduce code size; check here not in the caller */
1188 0 : return;
1189 :
1190 8 : info_ptr->colorspace = png_ptr->colorspace;
1191 8 : png_colorspace_sync_info(png_ptr, info_ptr);
1192 : }
1193 : #endif
1194 : #endif /* GAMMA */
1195 :
1196 : #ifdef PNG_COLORSPACE_SUPPORTED
1197 : /* Added at libpng-1.5.5 to support read and write of true CIEXYZ values for
1198 : * cHRM, as opposed to using chromaticities. These internal APIs return
1199 : * non-zero on a parameter error. The X, Y and Z values are required to be
1200 : * positive and less than 1.0.
1201 : */
1202 : static int
1203 0 : png_xy_from_XYZ(png_xy *xy, const png_XYZ *XYZ)
1204 : {
1205 : png_int_32 d, dwhite, whiteX, whiteY;
1206 :
1207 0 : d = XYZ->red_X + XYZ->red_Y + XYZ->red_Z;
1208 0 : if (png_muldiv(&xy->redx, XYZ->red_X, PNG_FP_1, d) == 0)
1209 0 : return 1;
1210 0 : if (png_muldiv(&xy->redy, XYZ->red_Y, PNG_FP_1, d) == 0)
1211 0 : return 1;
1212 0 : dwhite = d;
1213 0 : whiteX = XYZ->red_X;
1214 0 : whiteY = XYZ->red_Y;
1215 :
1216 0 : d = XYZ->green_X + XYZ->green_Y + XYZ->green_Z;
1217 0 : if (png_muldiv(&xy->greenx, XYZ->green_X, PNG_FP_1, d) == 0)
1218 0 : return 1;
1219 0 : if (png_muldiv(&xy->greeny, XYZ->green_Y, PNG_FP_1, d) == 0)
1220 0 : return 1;
1221 0 : dwhite += d;
1222 0 : whiteX += XYZ->green_X;
1223 0 : whiteY += XYZ->green_Y;
1224 :
1225 0 : d = XYZ->blue_X + XYZ->blue_Y + XYZ->blue_Z;
1226 0 : if (png_muldiv(&xy->bluex, XYZ->blue_X, PNG_FP_1, d) == 0)
1227 0 : return 1;
1228 0 : if (png_muldiv(&xy->bluey, XYZ->blue_Y, PNG_FP_1, d) == 0)
1229 0 : return 1;
1230 0 : dwhite += d;
1231 0 : whiteX += XYZ->blue_X;
1232 0 : whiteY += XYZ->blue_Y;
1233 :
1234 : /* The reference white is simply the sum of the end-point (X,Y,Z) vectors,
1235 : * thus:
1236 : */
1237 0 : if (png_muldiv(&xy->whitex, whiteX, PNG_FP_1, dwhite) == 0)
1238 0 : return 1;
1239 0 : if (png_muldiv(&xy->whitey, whiteY, PNG_FP_1, dwhite) == 0)
1240 0 : return 1;
1241 :
1242 0 : return 0;
1243 : }
1244 :
1245 : static int
1246 0 : png_XYZ_from_xy(png_XYZ *XYZ, const png_xy *xy)
1247 : {
1248 : png_fixed_point red_inverse, green_inverse, blue_scale;
1249 : png_fixed_point left, right, denominator;
1250 :
1251 : /* Check xy and, implicitly, z. Note that wide gamut color spaces typically
1252 : * have end points with 0 tristimulus values (these are impossible end
1253 : * points, but they are used to cover the possible colors). We check
1254 : * xy->whitey against 5, not 0, to avoid a possible integer overflow.
1255 : */
1256 0 : if (xy->redx < 0 || xy->redx > PNG_FP_1) return 1;
1257 0 : if (xy->redy < 0 || xy->redy > PNG_FP_1-xy->redx) return 1;
1258 0 : if (xy->greenx < 0 || xy->greenx > PNG_FP_1) return 1;
1259 0 : if (xy->greeny < 0 || xy->greeny > PNG_FP_1-xy->greenx) return 1;
1260 0 : if (xy->bluex < 0 || xy->bluex > PNG_FP_1) return 1;
1261 0 : if (xy->bluey < 0 || xy->bluey > PNG_FP_1-xy->bluex) return 1;
1262 0 : if (xy->whitex < 0 || xy->whitex > PNG_FP_1) return 1;
1263 0 : if (xy->whitey < 5 || xy->whitey > PNG_FP_1-xy->whitex) return 1;
1264 :
1265 : /* The reverse calculation is more difficult because the original tristimulus
1266 : * value had 9 independent values (red,green,blue)x(X,Y,Z) however only 8
1267 : * derived values were recorded in the cHRM chunk;
1268 : * (red,green,blue,white)x(x,y). This loses one degree of freedom and
1269 : * therefore an arbitrary ninth value has to be introduced to undo the
1270 : * original transformations.
1271 : *
1272 : * Think of the original end-points as points in (X,Y,Z) space. The
1273 : * chromaticity values (c) have the property:
1274 : *
1275 : * C
1276 : * c = ---------
1277 : * X + Y + Z
1278 : *
1279 : * For each c (x,y,z) from the corresponding original C (X,Y,Z). Thus the
1280 : * three chromaticity values (x,y,z) for each end-point obey the
1281 : * relationship:
1282 : *
1283 : * x + y + z = 1
1284 : *
1285 : * This describes the plane in (X,Y,Z) space that intersects each axis at the
1286 : * value 1.0; call this the chromaticity plane. Thus the chromaticity
1287 : * calculation has scaled each end-point so that it is on the x+y+z=1 plane
1288 : * and chromaticity is the intersection of the vector from the origin to the
1289 : * (X,Y,Z) value with the chromaticity plane.
1290 : *
1291 : * To fully invert the chromaticity calculation we would need the three
1292 : * end-point scale factors, (red-scale, green-scale, blue-scale), but these
1293 : * were not recorded. Instead we calculated the reference white (X,Y,Z) and
1294 : * recorded the chromaticity of this. The reference white (X,Y,Z) would have
1295 : * given all three of the scale factors since:
1296 : *
1297 : * color-C = color-c * color-scale
1298 : * white-C = red-C + green-C + blue-C
1299 : * = red-c*red-scale + green-c*green-scale + blue-c*blue-scale
1300 : *
1301 : * But cHRM records only white-x and white-y, so we have lost the white scale
1302 : * factor:
1303 : *
1304 : * white-C = white-c*white-scale
1305 : *
1306 : * To handle this the inverse transformation makes an arbitrary assumption
1307 : * about white-scale:
1308 : *
1309 : * Assume: white-Y = 1.0
1310 : * Hence: white-scale = 1/white-y
1311 : * Or: red-Y + green-Y + blue-Y = 1.0
1312 : *
1313 : * Notice the last statement of the assumption gives an equation in three of
1314 : * the nine values we want to calculate. 8 more equations come from the
1315 : * above routine as summarised at the top above (the chromaticity
1316 : * calculation):
1317 : *
1318 : * Given: color-x = color-X / (color-X + color-Y + color-Z)
1319 : * Hence: (color-x - 1)*color-X + color.x*color-Y + color.x*color-Z = 0
1320 : *
1321 : * This is 9 simultaneous equations in the 9 variables "color-C" and can be
1322 : * solved by Cramer's rule. Cramer's rule requires calculating 10 9x9 matrix
1323 : * determinants, however this is not as bad as it seems because only 28 of
1324 : * the total of 90 terms in the various matrices are non-zero. Nevertheless
1325 : * Cramer's rule is notoriously numerically unstable because the determinant
1326 : * calculation involves the difference of large, but similar, numbers. It is
1327 : * difficult to be sure that the calculation is stable for real world values
1328 : * and it is certain that it becomes unstable where the end points are close
1329 : * together.
1330 : *
1331 : * So this code uses the perhaps slightly less optimal but more
1332 : * understandable and totally obvious approach of calculating color-scale.
1333 : *
1334 : * This algorithm depends on the precision in white-scale and that is
1335 : * (1/white-y), so we can immediately see that as white-y approaches 0 the
1336 : * accuracy inherent in the cHRM chunk drops off substantially.
1337 : *
1338 : * libpng arithmetic: a simple inversion of the above equations
1339 : * ------------------------------------------------------------
1340 : *
1341 : * white_scale = 1/white-y
1342 : * white-X = white-x * white-scale
1343 : * white-Y = 1.0
1344 : * white-Z = (1 - white-x - white-y) * white_scale
1345 : *
1346 : * white-C = red-C + green-C + blue-C
1347 : * = red-c*red-scale + green-c*green-scale + blue-c*blue-scale
1348 : *
1349 : * This gives us three equations in (red-scale,green-scale,blue-scale) where
1350 : * all the coefficients are now known:
1351 : *
1352 : * red-x*red-scale + green-x*green-scale + blue-x*blue-scale
1353 : * = white-x/white-y
1354 : * red-y*red-scale + green-y*green-scale + blue-y*blue-scale = 1
1355 : * red-z*red-scale + green-z*green-scale + blue-z*blue-scale
1356 : * = (1 - white-x - white-y)/white-y
1357 : *
1358 : * In the last equation color-z is (1 - color-x - color-y) so we can add all
1359 : * three equations together to get an alternative third:
1360 : *
1361 : * red-scale + green-scale + blue-scale = 1/white-y = white-scale
1362 : *
1363 : * So now we have a Cramer's rule solution where the determinants are just
1364 : * 3x3 - far more tractible. Unfortunately 3x3 determinants still involve
1365 : * multiplication of three coefficients so we can't guarantee to avoid
1366 : * overflow in the libpng fixed point representation. Using Cramer's rule in
1367 : * floating point is probably a good choice here, but it's not an option for
1368 : * fixed point. Instead proceed to simplify the first two equations by
1369 : * eliminating what is likely to be the largest value, blue-scale:
1370 : *
1371 : * blue-scale = white-scale - red-scale - green-scale
1372 : *
1373 : * Hence:
1374 : *
1375 : * (red-x - blue-x)*red-scale + (green-x - blue-x)*green-scale =
1376 : * (white-x - blue-x)*white-scale
1377 : *
1378 : * (red-y - blue-y)*red-scale + (green-y - blue-y)*green-scale =
1379 : * 1 - blue-y*white-scale
1380 : *
1381 : * And now we can trivially solve for (red-scale,green-scale):
1382 : *
1383 : * green-scale =
1384 : * (white-x - blue-x)*white-scale - (red-x - blue-x)*red-scale
1385 : * -----------------------------------------------------------
1386 : * green-x - blue-x
1387 : *
1388 : * red-scale =
1389 : * 1 - blue-y*white-scale - (green-y - blue-y) * green-scale
1390 : * ---------------------------------------------------------
1391 : * red-y - blue-y
1392 : *
1393 : * Hence:
1394 : *
1395 : * red-scale =
1396 : * ( (green-x - blue-x) * (white-y - blue-y) -
1397 : * (green-y - blue-y) * (white-x - blue-x) ) / white-y
1398 : * -------------------------------------------------------------------------
1399 : * (green-x - blue-x)*(red-y - blue-y)-(green-y - blue-y)*(red-x - blue-x)
1400 : *
1401 : * green-scale =
1402 : * ( (red-y - blue-y) * (white-x - blue-x) -
1403 : * (red-x - blue-x) * (white-y - blue-y) ) / white-y
1404 : * -------------------------------------------------------------------------
1405 : * (green-x - blue-x)*(red-y - blue-y)-(green-y - blue-y)*(red-x - blue-x)
1406 : *
1407 : * Accuracy:
1408 : * The input values have 5 decimal digits of accuracy. The values are all in
1409 : * the range 0 < value < 1, so simple products are in the same range but may
1410 : * need up to 10 decimal digits to preserve the original precision and avoid
1411 : * underflow. Because we are using a 32-bit signed representation we cannot
1412 : * match this; the best is a little over 9 decimal digits, less than 10.
1413 : *
1414 : * The approach used here is to preserve the maximum precision within the
1415 : * signed representation. Because the red-scale calculation above uses the
1416 : * difference between two products of values that must be in the range -1..+1
1417 : * it is sufficient to divide the product by 7; ceil(100,000/32767*2). The
1418 : * factor is irrelevant in the calculation because it is applied to both
1419 : * numerator and denominator.
1420 : *
1421 : * Note that the values of the differences of the products of the
1422 : * chromaticities in the above equations tend to be small, for example for
1423 : * the sRGB chromaticities they are:
1424 : *
1425 : * red numerator: -0.04751
1426 : * green numerator: -0.08788
1427 : * denominator: -0.2241 (without white-y multiplication)
1428 : *
1429 : * The resultant Y coefficients from the chromaticities of some widely used
1430 : * color space definitions are (to 15 decimal places):
1431 : *
1432 : * sRGB
1433 : * 0.212639005871510 0.715168678767756 0.072192315360734
1434 : * Kodak ProPhoto
1435 : * 0.288071128229293 0.711843217810102 0.000085653960605
1436 : * Adobe RGB
1437 : * 0.297344975250536 0.627363566255466 0.075291458493998
1438 : * Adobe Wide Gamut RGB
1439 : * 0.258728243040113 0.724682314948566 0.016589442011321
1440 : */
1441 : /* By the argument, above overflow should be impossible here. The return
1442 : * value of 2 indicates an internal error to the caller.
1443 : */
1444 0 : if (png_muldiv(&left, xy->greenx-xy->bluex, xy->redy - xy->bluey, 7) == 0)
1445 0 : return 2;
1446 0 : if (png_muldiv(&right, xy->greeny-xy->bluey, xy->redx - xy->bluex, 7) == 0)
1447 0 : return 2;
1448 0 : denominator = left - right;
1449 :
1450 : /* Now find the red numerator. */
1451 0 : if (png_muldiv(&left, xy->greenx-xy->bluex, xy->whitey-xy->bluey, 7) == 0)
1452 0 : return 2;
1453 0 : if (png_muldiv(&right, xy->greeny-xy->bluey, xy->whitex-xy->bluex, 7) == 0)
1454 0 : return 2;
1455 :
1456 : /* Overflow is possible here and it indicates an extreme set of PNG cHRM
1457 : * chunk values. This calculation actually returns the reciprocal of the
1458 : * scale value because this allows us to delay the multiplication of white-y
1459 : * into the denominator, which tends to produce a small number.
1460 : */
1461 0 : if (png_muldiv(&red_inverse, xy->whitey, denominator, left-right) == 0 ||
1462 0 : red_inverse <= xy->whitey /* r+g+b scales = white scale */)
1463 0 : return 1;
1464 :
1465 : /* Similarly for green_inverse: */
1466 0 : if (png_muldiv(&left, xy->redy-xy->bluey, xy->whitex-xy->bluex, 7) == 0)
1467 0 : return 2;
1468 0 : if (png_muldiv(&right, xy->redx-xy->bluex, xy->whitey-xy->bluey, 7) == 0)
1469 0 : return 2;
1470 0 : if (png_muldiv(&green_inverse, xy->whitey, denominator, left-right) == 0 ||
1471 0 : green_inverse <= xy->whitey)
1472 0 : return 1;
1473 :
1474 : /* And the blue scale, the checks above guarantee this can't overflow but it
1475 : * can still produce 0 for extreme cHRM values.
1476 : */
1477 0 : blue_scale = png_reciprocal(xy->whitey) - png_reciprocal(red_inverse) -
1478 0 : png_reciprocal(green_inverse);
1479 0 : if (blue_scale <= 0)
1480 0 : return 1;
1481 :
1482 :
1483 : /* And fill in the png_XYZ: */
1484 0 : if (png_muldiv(&XYZ->red_X, xy->redx, PNG_FP_1, red_inverse) == 0)
1485 0 : return 1;
1486 0 : if (png_muldiv(&XYZ->red_Y, xy->redy, PNG_FP_1, red_inverse) == 0)
1487 0 : return 1;
1488 0 : if (png_muldiv(&XYZ->red_Z, PNG_FP_1 - xy->redx - xy->redy, PNG_FP_1,
1489 : red_inverse) == 0)
1490 0 : return 1;
1491 :
1492 0 : if (png_muldiv(&XYZ->green_X, xy->greenx, PNG_FP_1, green_inverse) == 0)
1493 0 : return 1;
1494 0 : if (png_muldiv(&XYZ->green_Y, xy->greeny, PNG_FP_1, green_inverse) == 0)
1495 0 : return 1;
1496 0 : if (png_muldiv(&XYZ->green_Z, PNG_FP_1 - xy->greenx - xy->greeny, PNG_FP_1,
1497 : green_inverse) == 0)
1498 0 : return 1;
1499 :
1500 0 : if (png_muldiv(&XYZ->blue_X, xy->bluex, blue_scale, PNG_FP_1) == 0)
1501 0 : return 1;
1502 0 : if (png_muldiv(&XYZ->blue_Y, xy->bluey, blue_scale, PNG_FP_1) == 0)
1503 0 : return 1;
1504 0 : if (png_muldiv(&XYZ->blue_Z, PNG_FP_1 - xy->bluex - xy->bluey, blue_scale,
1505 : PNG_FP_1) == 0)
1506 0 : return 1;
1507 :
1508 0 : return 0; /*success*/
1509 : }
1510 :
1511 : static int
1512 0 : png_XYZ_normalize(png_XYZ *XYZ)
1513 : {
1514 : png_int_32 Y;
1515 :
1516 0 : if (XYZ->red_Y < 0 || XYZ->green_Y < 0 || XYZ->blue_Y < 0 ||
1517 0 : XYZ->red_X < 0 || XYZ->green_X < 0 || XYZ->blue_X < 0 ||
1518 0 : XYZ->red_Z < 0 || XYZ->green_Z < 0 || XYZ->blue_Z < 0)
1519 0 : return 1;
1520 :
1521 : /* Normalize by scaling so the sum of the end-point Y values is PNG_FP_1.
1522 : * IMPLEMENTATION NOTE: ANSI requires signed overflow not to occur, therefore
1523 : * relying on addition of two positive values producing a negative one is not
1524 : * safe.
1525 : */
1526 0 : Y = XYZ->red_Y;
1527 0 : if (0x7fffffff - Y < XYZ->green_X)
1528 0 : return 1;
1529 0 : Y += XYZ->green_Y;
1530 0 : if (0x7fffffff - Y < XYZ->blue_X)
1531 0 : return 1;
1532 0 : Y += XYZ->blue_Y;
1533 :
1534 0 : if (Y != PNG_FP_1)
1535 : {
1536 0 : if (png_muldiv(&XYZ->red_X, XYZ->red_X, PNG_FP_1, Y) == 0)
1537 0 : return 1;
1538 0 : if (png_muldiv(&XYZ->red_Y, XYZ->red_Y, PNG_FP_1, Y) == 0)
1539 0 : return 1;
1540 0 : if (png_muldiv(&XYZ->red_Z, XYZ->red_Z, PNG_FP_1, Y) == 0)
1541 0 : return 1;
1542 :
1543 0 : if (png_muldiv(&XYZ->green_X, XYZ->green_X, PNG_FP_1, Y) == 0)
1544 0 : return 1;
1545 0 : if (png_muldiv(&XYZ->green_Y, XYZ->green_Y, PNG_FP_1, Y) == 0)
1546 0 : return 1;
1547 0 : if (png_muldiv(&XYZ->green_Z, XYZ->green_Z, PNG_FP_1, Y) == 0)
1548 0 : return 1;
1549 :
1550 0 : if (png_muldiv(&XYZ->blue_X, XYZ->blue_X, PNG_FP_1, Y) == 0)
1551 0 : return 1;
1552 0 : if (png_muldiv(&XYZ->blue_Y, XYZ->blue_Y, PNG_FP_1, Y) == 0)
1553 0 : return 1;
1554 0 : if (png_muldiv(&XYZ->blue_Z, XYZ->blue_Z, PNG_FP_1, Y) == 0)
1555 0 : return 1;
1556 : }
1557 :
1558 0 : return 0;
1559 : }
1560 :
1561 : static int
1562 0 : png_colorspace_endpoints_match(const png_xy *xy1, const png_xy *xy2, int delta)
1563 : {
1564 : /* Allow an error of +/-0.01 (absolute value) on each chromaticity */
1565 0 : if (PNG_OUT_OF_RANGE(xy1->whitex, xy2->whitex,delta) ||
1566 0 : PNG_OUT_OF_RANGE(xy1->whitey, xy2->whitey,delta) ||
1567 0 : PNG_OUT_OF_RANGE(xy1->redx, xy2->redx, delta) ||
1568 0 : PNG_OUT_OF_RANGE(xy1->redy, xy2->redy, delta) ||
1569 0 : PNG_OUT_OF_RANGE(xy1->greenx, xy2->greenx,delta) ||
1570 0 : PNG_OUT_OF_RANGE(xy1->greeny, xy2->greeny,delta) ||
1571 0 : PNG_OUT_OF_RANGE(xy1->bluex, xy2->bluex, delta) ||
1572 0 : PNG_OUT_OF_RANGE(xy1->bluey, xy2->bluey, delta))
1573 0 : return 0;
1574 0 : return 1;
1575 : }
1576 :
1577 : /* Added in libpng-1.6.0, a different check for the validity of a set of cHRM
1578 : * chunk chromaticities. Earlier checks used to simply look for the overflow
1579 : * condition (where the determinant of the matrix to solve for XYZ ends up zero
1580 : * because the chromaticity values are not all distinct.) Despite this it is
1581 : * theoretically possible to produce chromaticities that are apparently valid
1582 : * but that rapidly degrade to invalid, potentially crashing, sets because of
1583 : * arithmetic inaccuracies when calculations are performed on them. The new
1584 : * check is to round-trip xy -> XYZ -> xy and then check that the result is
1585 : * within a small percentage of the original.
1586 : */
1587 : static int
1588 0 : png_colorspace_check_xy(png_XYZ *XYZ, const png_xy *xy)
1589 : {
1590 : int result;
1591 : png_xy xy_test;
1592 :
1593 : /* As a side-effect this routine also returns the XYZ endpoints. */
1594 0 : result = png_XYZ_from_xy(XYZ, xy);
1595 0 : if (result != 0)
1596 0 : return result;
1597 :
1598 0 : result = png_xy_from_XYZ(&xy_test, XYZ);
1599 0 : if (result != 0)
1600 0 : return result;
1601 :
1602 0 : if (png_colorspace_endpoints_match(xy, &xy_test,
1603 : 5/*actually, the math is pretty accurate*/) != 0)
1604 0 : return 0;
1605 :
1606 : /* Too much slip */
1607 0 : return 1;
1608 : }
1609 :
1610 : /* This is the check going the other way. The XYZ is modified to normalize it
1611 : * (another side-effect) and the xy chromaticities are returned.
1612 : */
1613 : static int
1614 0 : png_colorspace_check_XYZ(png_xy *xy, png_XYZ *XYZ)
1615 : {
1616 : int result;
1617 : png_XYZ XYZtemp;
1618 :
1619 0 : result = png_XYZ_normalize(XYZ);
1620 0 : if (result != 0)
1621 0 : return result;
1622 :
1623 0 : result = png_xy_from_XYZ(xy, XYZ);
1624 0 : if (result != 0)
1625 0 : return result;
1626 :
1627 0 : XYZtemp = *XYZ;
1628 0 : return png_colorspace_check_xy(&XYZtemp, xy);
1629 : }
1630 :
1631 : /* Used to check for an endpoint match against sRGB */
1632 : static const png_xy sRGB_xy = /* From ITU-R BT.709-3 */
1633 : {
1634 : /* color x y */
1635 : /* red */ 64000, 33000,
1636 : /* green */ 30000, 60000,
1637 : /* blue */ 15000, 6000,
1638 : /* white */ 31270, 32900
1639 : };
1640 :
1641 : static int
1642 0 : png_colorspace_set_xy_and_XYZ(png_const_structrp png_ptr,
1643 : png_colorspacerp colorspace, const png_xy *xy, const png_XYZ *XYZ,
1644 : int preferred)
1645 : {
1646 0 : if ((colorspace->flags & PNG_COLORSPACE_INVALID) != 0)
1647 0 : return 0;
1648 :
1649 : /* The consistency check is performed on the chromaticities; this factors out
1650 : * variations because of the normalization (or not) of the end point Y
1651 : * values.
1652 : */
1653 0 : if (preferred < 2 &&
1654 0 : (colorspace->flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
1655 : {
1656 : /* The end points must be reasonably close to any we already have. The
1657 : * following allows an error of up to +/-.001
1658 : */
1659 0 : if (png_colorspace_endpoints_match(xy, &colorspace->end_points_xy,
1660 : 100) == 0)
1661 : {
1662 0 : colorspace->flags |= PNG_COLORSPACE_INVALID;
1663 0 : png_benign_error(png_ptr, "inconsistent chromaticities");
1664 0 : return 0; /* failed */
1665 : }
1666 :
1667 : /* Only overwrite with preferred values */
1668 0 : if (preferred == 0)
1669 0 : return 1; /* ok, but no change */
1670 : }
1671 :
1672 0 : colorspace->end_points_xy = *xy;
1673 0 : colorspace->end_points_XYZ = *XYZ;
1674 0 : colorspace->flags |= PNG_COLORSPACE_HAVE_ENDPOINTS;
1675 :
1676 : /* The end points are normally quoted to two decimal digits, so allow +/-0.01
1677 : * on this test.
1678 : */
1679 0 : if (png_colorspace_endpoints_match(xy, &sRGB_xy, 1000) != 0)
1680 0 : colorspace->flags |= PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB;
1681 :
1682 : else
1683 0 : colorspace->flags &= PNG_COLORSPACE_CANCEL(
1684 : PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB);
1685 :
1686 0 : return 2; /* ok and changed */
1687 : }
1688 :
1689 : int /* PRIVATE */
1690 0 : png_colorspace_set_chromaticities(png_const_structrp png_ptr,
1691 : png_colorspacerp colorspace, const png_xy *xy, int preferred)
1692 : {
1693 : /* We must check the end points to ensure they are reasonable - in the past
1694 : * color management systems have crashed as a result of getting bogus
1695 : * colorant values, while this isn't the fault of libpng it is the
1696 : * responsibility of libpng because PNG carries the bomb and libpng is in a
1697 : * position to protect against it.
1698 : */
1699 : png_XYZ XYZ;
1700 :
1701 0 : switch (png_colorspace_check_xy(&XYZ, xy))
1702 : {
1703 : case 0: /* success */
1704 0 : return png_colorspace_set_xy_and_XYZ(png_ptr, colorspace, xy, &XYZ,
1705 : preferred);
1706 :
1707 : case 1:
1708 : /* We can't invert the chromaticities so we can't produce value XYZ
1709 : * values. Likely as not a color management system will fail too.
1710 : */
1711 0 : colorspace->flags |= PNG_COLORSPACE_INVALID;
1712 0 : png_benign_error(png_ptr, "invalid chromaticities");
1713 0 : break;
1714 :
1715 : default:
1716 : /* libpng is broken; this should be a warning but if it happens we
1717 : * want error reports so for the moment it is an error.
1718 : */
1719 0 : colorspace->flags |= PNG_COLORSPACE_INVALID;
1720 0 : png_error(png_ptr, "internal error checking chromaticities");
1721 : }
1722 :
1723 0 : return 0; /* failed */
1724 : }
1725 :
1726 : int /* PRIVATE */
1727 0 : png_colorspace_set_endpoints(png_const_structrp png_ptr,
1728 : png_colorspacerp colorspace, const png_XYZ *XYZ_in, int preferred)
1729 : {
1730 0 : png_XYZ XYZ = *XYZ_in;
1731 : png_xy xy;
1732 :
1733 0 : switch (png_colorspace_check_XYZ(&xy, &XYZ))
1734 : {
1735 : case 0:
1736 0 : return png_colorspace_set_xy_and_XYZ(png_ptr, colorspace, &xy, &XYZ,
1737 : preferred);
1738 :
1739 : case 1:
1740 : /* End points are invalid. */
1741 0 : colorspace->flags |= PNG_COLORSPACE_INVALID;
1742 0 : png_benign_error(png_ptr, "invalid end points");
1743 0 : break;
1744 :
1745 : default:
1746 0 : colorspace->flags |= PNG_COLORSPACE_INVALID;
1747 0 : png_error(png_ptr, "internal error checking chromaticities");
1748 : }
1749 :
1750 0 : return 0; /* failed */
1751 : }
1752 :
1753 : #if defined(PNG_sRGB_SUPPORTED) || defined(PNG_iCCP_SUPPORTED)
1754 : /* Error message generation */
1755 : static char
1756 0 : png_icc_tag_char(png_uint_32 byte)
1757 : {
1758 0 : byte &= 0xff;
1759 0 : if (byte >= 32 && byte <= 126)
1760 0 : return (char)byte;
1761 : else
1762 0 : return '?';
1763 : }
1764 :
1765 : static void
1766 0 : png_icc_tag_name(char *name, png_uint_32 tag)
1767 : {
1768 0 : name[0] = '\'';
1769 0 : name[1] = png_icc_tag_char(tag >> 24);
1770 0 : name[2] = png_icc_tag_char(tag >> 16);
1771 0 : name[3] = png_icc_tag_char(tag >> 8);
1772 0 : name[4] = png_icc_tag_char(tag );
1773 0 : name[5] = '\'';
1774 0 : }
1775 :
1776 : static int
1777 0 : is_ICC_signature_char(png_alloc_size_t it)
1778 : {
1779 0 : return it == 32 || (it >= 48 && it <= 57) || (it >= 65 && it <= 90) ||
1780 0 : (it >= 97 && it <= 122);
1781 : }
1782 :
1783 : static int
1784 0 : is_ICC_signature(png_alloc_size_t it)
1785 : {
1786 0 : return is_ICC_signature_char(it >> 24) /* checks all the top bits */ &&
1787 0 : is_ICC_signature_char((it >> 16) & 0xff) &&
1788 0 : is_ICC_signature_char((it >> 8) & 0xff) &&
1789 0 : is_ICC_signature_char(it & 0xff);
1790 : }
1791 :
1792 : static int
1793 0 : png_icc_profile_error(png_const_structrp png_ptr, png_colorspacerp colorspace,
1794 : png_const_charp name, png_alloc_size_t value, png_const_charp reason)
1795 : {
1796 : size_t pos;
1797 : char message[196]; /* see below for calculation */
1798 :
1799 0 : if (colorspace != NULL)
1800 0 : colorspace->flags |= PNG_COLORSPACE_INVALID;
1801 :
1802 0 : pos = png_safecat(message, (sizeof message), 0, "profile '"); /* 9 chars */
1803 0 : pos = png_safecat(message, pos+79, pos, name); /* Truncate to 79 chars */
1804 0 : pos = png_safecat(message, (sizeof message), pos, "': "); /* +2 = 90 */
1805 0 : if (is_ICC_signature(value) != 0)
1806 : {
1807 : /* So 'value' is at most 4 bytes and the following cast is safe */
1808 0 : png_icc_tag_name(message+pos, (png_uint_32)value);
1809 0 : pos += 6; /* total +8; less than the else clause */
1810 0 : message[pos++] = ':';
1811 0 : message[pos++] = ' ';
1812 : }
1813 : # ifdef PNG_WARNINGS_SUPPORTED
1814 : else
1815 : {
1816 : char number[PNG_NUMBER_BUFFER_SIZE]; /* +24 = 114*/
1817 :
1818 0 : pos = png_safecat(message, (sizeof message), pos,
1819 0 : png_format_number(number, number+(sizeof number),
1820 : PNG_NUMBER_FORMAT_x, value));
1821 0 : pos = png_safecat(message, (sizeof message), pos, "h: "); /*+2 = 116*/
1822 : }
1823 : # endif
1824 : /* The 'reason' is an arbitrary message, allow +79 maximum 195 */
1825 0 : pos = png_safecat(message, (sizeof message), pos, reason);
1826 : PNG_UNUSED(pos)
1827 :
1828 : /* This is recoverable, but make it unconditionally an app_error on write to
1829 : * avoid writing invalid ICC profiles into PNG files (i.e., we handle them
1830 : * on read, with a warning, but on write unless the app turns off
1831 : * application errors the PNG won't be written.)
1832 : */
1833 0 : png_chunk_report(png_ptr, message,
1834 : (colorspace != NULL) ? PNG_CHUNK_ERROR : PNG_CHUNK_WRITE_ERROR);
1835 :
1836 0 : return 0;
1837 : }
1838 : #endif /* sRGB || iCCP */
1839 :
1840 : #ifdef PNG_sRGB_SUPPORTED
1841 : int /* PRIVATE */
1842 8 : png_colorspace_set_sRGB(png_const_structrp png_ptr, png_colorspacerp colorspace,
1843 : int intent)
1844 : {
1845 : /* sRGB sets known gamma, end points and (from the chunk) intent. */
1846 : /* IMPORTANT: these are not necessarily the values found in an ICC profile
1847 : * because ICC profiles store values adapted to a D50 environment; it is
1848 : * expected that the ICC profile mediaWhitePointTag will be D50; see the
1849 : * checks and code elsewhere to understand this better.
1850 : *
1851 : * These XYZ values, which are accurate to 5dp, produce rgb to gray
1852 : * coefficients of (6968,23435,2366), which are reduced (because they add up
1853 : * to 32769 not 32768) to (6968,23434,2366). These are the values that
1854 : * libpng has traditionally used (and are the best values given the 15bit
1855 : * algorithm used by the rgb to gray code.)
1856 : */
1857 : static const png_XYZ sRGB_XYZ = /* D65 XYZ (*not* the D50 adapted values!) */
1858 : {
1859 : /* color X Y Z */
1860 : /* red */ 41239, 21264, 1933,
1861 : /* green */ 35758, 71517, 11919,
1862 : /* blue */ 18048, 7219, 95053
1863 : };
1864 :
1865 : /* Do nothing if the colorspace is already invalidated. */
1866 8 : if ((colorspace->flags & PNG_COLORSPACE_INVALID) != 0)
1867 0 : return 0;
1868 :
1869 : /* Check the intent, then check for existing settings. It is valid for the
1870 : * PNG file to have cHRM or gAMA chunks along with sRGB, but the values must
1871 : * be consistent with the correct values. If, however, this function is
1872 : * called below because an iCCP chunk matches sRGB then it is quite
1873 : * conceivable that an older app recorded incorrect gAMA and cHRM because of
1874 : * an incorrect calculation based on the values in the profile - this does
1875 : * *not* invalidate the profile (though it still produces an error, which can
1876 : * be ignored.)
1877 : */
1878 8 : if (intent < 0 || intent >= PNG_sRGB_INTENT_LAST)
1879 0 : return png_icc_profile_error(png_ptr, colorspace, "sRGB",
1880 0 : (unsigned)intent, "invalid sRGB rendering intent");
1881 :
1882 8 : if ((colorspace->flags & PNG_COLORSPACE_HAVE_INTENT) != 0 &&
1883 0 : colorspace->rendering_intent != intent)
1884 0 : return png_icc_profile_error(png_ptr, colorspace, "sRGB",
1885 0 : (unsigned)intent, "inconsistent rendering intents");
1886 :
1887 8 : if ((colorspace->flags & PNG_COLORSPACE_FROM_sRGB) != 0)
1888 : {
1889 0 : png_benign_error(png_ptr, "duplicate sRGB information ignored");
1890 0 : return 0;
1891 : }
1892 :
1893 : /* If the standard sRGB cHRM chunk does not match the one from the PNG file
1894 : * warn but overwrite the value with the correct one.
1895 : */
1896 8 : if ((colorspace->flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0 &&
1897 0 : !png_colorspace_endpoints_match(&sRGB_xy, &colorspace->end_points_xy,
1898 : 100))
1899 0 : png_chunk_report(png_ptr, "cHRM chunk does not match sRGB",
1900 : PNG_CHUNK_ERROR);
1901 :
1902 : /* This check is just done for the error reporting - the routine always
1903 : * returns true when the 'from' argument corresponds to sRGB (2).
1904 : */
1905 8 : (void)png_colorspace_check_gamma(png_ptr, colorspace, PNG_GAMMA_sRGB_INVERSE,
1906 : 2/*from sRGB*/);
1907 :
1908 : /* intent: bugs in GCC force 'int' to be used as the parameter type. */
1909 8 : colorspace->rendering_intent = (png_uint_16)intent;
1910 8 : colorspace->flags |= PNG_COLORSPACE_HAVE_INTENT;
1911 :
1912 : /* endpoints */
1913 8 : colorspace->end_points_xy = sRGB_xy;
1914 8 : colorspace->end_points_XYZ = sRGB_XYZ;
1915 8 : colorspace->flags |=
1916 : (PNG_COLORSPACE_HAVE_ENDPOINTS|PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB);
1917 :
1918 : /* gamma */
1919 8 : colorspace->gamma = PNG_GAMMA_sRGB_INVERSE;
1920 8 : colorspace->flags |= PNG_COLORSPACE_HAVE_GAMMA;
1921 :
1922 : /* Finally record that we have an sRGB profile */
1923 8 : colorspace->flags |=
1924 : (PNG_COLORSPACE_MATCHES_sRGB|PNG_COLORSPACE_FROM_sRGB);
1925 :
1926 8 : return 1; /* set */
1927 : }
1928 : #endif /* sRGB */
1929 :
1930 : #ifdef PNG_iCCP_SUPPORTED
1931 : /* Encoded value of D50 as an ICC XYZNumber. From the ICC 2010 spec the value
1932 : * is XYZ(0.9642,1.0,0.8249), which scales to:
1933 : *
1934 : * (63189.8112, 65536, 54060.6464)
1935 : */
1936 : static const png_byte D50_nCIEXYZ[12] =
1937 : { 0x00, 0x00, 0xf6, 0xd6, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0xd3, 0x2d };
1938 :
1939 : static int /* bool */
1940 0 : icc_check_length(png_const_structrp png_ptr, png_colorspacerp colorspace,
1941 : png_const_charp name, png_uint_32 profile_length)
1942 : {
1943 0 : if (profile_length < 132)
1944 0 : return png_icc_profile_error(png_ptr, colorspace, name, profile_length,
1945 : "too short");
1946 :
1947 0 : return 1;
1948 : }
1949 :
1950 : #ifdef PNG_READ_iCCP_SUPPORTED
1951 : int /* PRIVATE */
1952 0 : png_icc_check_length(png_const_structrp png_ptr, png_colorspacerp colorspace,
1953 : png_const_charp name, png_uint_32 profile_length)
1954 : {
1955 0 : if (!icc_check_length(png_ptr, colorspace, name, profile_length))
1956 0 : return 0;
1957 :
1958 : /* This needs to be here because the 'normal' check is in
1959 : * png_decompress_chunk, yet this happens after the attempt to
1960 : * png_malloc_base the required data. We only need this on read; on write
1961 : * the caller supplies the profile buffer so libpng doesn't allocate it. See
1962 : * the call to icc_check_length below (the write case).
1963 : */
1964 : # ifdef PNG_SET_USER_LIMITS_SUPPORTED
1965 0 : else if (png_ptr->user_chunk_malloc_max > 0 &&
1966 0 : png_ptr->user_chunk_malloc_max < profile_length)
1967 0 : return png_icc_profile_error(png_ptr, colorspace, name, profile_length,
1968 : "exceeds application limits");
1969 : # elif PNG_USER_CHUNK_MALLOC_MAX > 0
1970 : else if (PNG_USER_CHUNK_MALLOC_MAX < profile_length)
1971 : return png_icc_profile_error(png_ptr, colorspace, name, profile_length,
1972 : "exceeds libpng limits");
1973 : # else /* !SET_USER_LIMITS */
1974 : /* This will get compiled out on all 32-bit and better systems. */
1975 : else if (PNG_SIZE_MAX < profile_length)
1976 : return png_icc_profile_error(png_ptr, colorspace, name, profile_length,
1977 : "exceeds system limits");
1978 : # endif /* !SET_USER_LIMITS */
1979 :
1980 0 : return 1;
1981 : }
1982 : #endif /* READ_iCCP */
1983 :
1984 : int /* PRIVATE */
1985 0 : png_icc_check_header(png_const_structrp png_ptr, png_colorspacerp colorspace,
1986 : png_const_charp name, png_uint_32 profile_length,
1987 : png_const_bytep profile/* first 132 bytes only */, int color_type)
1988 : {
1989 : png_uint_32 temp;
1990 :
1991 : /* Length check; this cannot be ignored in this code because profile_length
1992 : * is used later to check the tag table, so even if the profile seems over
1993 : * long profile_length from the caller must be correct. The caller can fix
1994 : * this up on read or write by just passing in the profile header length.
1995 : */
1996 0 : temp = png_get_uint_32(profile);
1997 0 : if (temp != profile_length)
1998 0 : return png_icc_profile_error(png_ptr, colorspace, name, temp,
1999 : "length does not match profile");
2000 :
2001 0 : temp = (png_uint_32) (*(profile+8));
2002 0 : if (temp > 3 && (profile_length & 3))
2003 0 : return png_icc_profile_error(png_ptr, colorspace, name, profile_length,
2004 : "invalid length");
2005 :
2006 0 : temp = png_get_uint_32(profile+128); /* tag count: 12 bytes/tag */
2007 0 : if (temp > 357913930 || /* (2^32-4-132)/12: maximum possible tag count */
2008 0 : profile_length < 132+12*temp) /* truncated tag table */
2009 0 : return png_icc_profile_error(png_ptr, colorspace, name, temp,
2010 : "tag count too large");
2011 :
2012 : /* The 'intent' must be valid or we can't store it, ICC limits the intent to
2013 : * 16 bits.
2014 : */
2015 0 : temp = png_get_uint_32(profile+64);
2016 0 : if (temp >= 0xffff) /* The ICC limit */
2017 0 : return png_icc_profile_error(png_ptr, colorspace, name, temp,
2018 : "invalid rendering intent");
2019 :
2020 : /* This is just a warning because the profile may be valid in future
2021 : * versions.
2022 : */
2023 0 : if (temp >= PNG_sRGB_INTENT_LAST)
2024 0 : (void)png_icc_profile_error(png_ptr, NULL, name, temp,
2025 : "intent outside defined range");
2026 :
2027 : /* At this point the tag table can't be checked because it hasn't necessarily
2028 : * been loaded; however, various header fields can be checked. These checks
2029 : * are for values permitted by the PNG spec in an ICC profile; the PNG spec
2030 : * restricts the profiles that can be passed in an iCCP chunk (they must be
2031 : * appropriate to processing PNG data!)
2032 : */
2033 :
2034 : /* Data checks (could be skipped). These checks must be independent of the
2035 : * version number; however, the version number doesn't accomodate changes in
2036 : * the header fields (just the known tags and the interpretation of the
2037 : * data.)
2038 : */
2039 0 : temp = png_get_uint_32(profile+36); /* signature 'ascp' */
2040 0 : if (temp != 0x61637370)
2041 0 : return png_icc_profile_error(png_ptr, colorspace, name, temp,
2042 : "invalid signature");
2043 :
2044 : /* Currently the PCS illuminant/adopted white point (the computational
2045 : * white point) are required to be D50,
2046 : * however the profile contains a record of the illuminant so perhaps ICC
2047 : * expects to be able to change this in the future (despite the rationale in
2048 : * the introduction for using a fixed PCS adopted white.) Consequently the
2049 : * following is just a warning.
2050 : */
2051 0 : if (memcmp(profile+68, D50_nCIEXYZ, 12) != 0)
2052 0 : (void)png_icc_profile_error(png_ptr, NULL, name, 0/*no tag value*/,
2053 : "PCS illuminant is not D50");
2054 :
2055 : /* The PNG spec requires this:
2056 : * "If the iCCP chunk is present, the image samples conform to the colour
2057 : * space represented by the embedded ICC profile as defined by the
2058 : * International Color Consortium [ICC]. The colour space of the ICC profile
2059 : * shall be an RGB colour space for colour images (PNG colour types 2, 3, and
2060 : * 6), or a greyscale colour space for greyscale images (PNG colour types 0
2061 : * and 4)."
2062 : *
2063 : * This checking code ensures the embedded profile (on either read or write)
2064 : * conforms to the specification requirements. Notice that an ICC 'gray'
2065 : * color-space profile contains the information to transform the monochrome
2066 : * data to XYZ or L*a*b (according to which PCS the profile uses) and this
2067 : * should be used in preference to the standard libpng K channel replication
2068 : * into R, G and B channels.
2069 : *
2070 : * Previously it was suggested that an RGB profile on grayscale data could be
2071 : * handled. However it it is clear that using an RGB profile in this context
2072 : * must be an error - there is no specification of what it means. Thus it is
2073 : * almost certainly more correct to ignore the profile.
2074 : */
2075 0 : temp = png_get_uint_32(profile+16); /* data colour space field */
2076 0 : switch (temp)
2077 : {
2078 : case 0x52474220: /* 'RGB ' */
2079 0 : if ((color_type & PNG_COLOR_MASK_COLOR) == 0)
2080 0 : return png_icc_profile_error(png_ptr, colorspace, name, temp,
2081 : "RGB color space not permitted on grayscale PNG");
2082 0 : break;
2083 :
2084 : case 0x47524159: /* 'GRAY' */
2085 0 : if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
2086 0 : return png_icc_profile_error(png_ptr, colorspace, name, temp,
2087 : "Gray color space not permitted on RGB PNG");
2088 0 : break;
2089 :
2090 : default:
2091 0 : return png_icc_profile_error(png_ptr, colorspace, name, temp,
2092 : "invalid ICC profile color space");
2093 : }
2094 :
2095 : /* It is up to the application to check that the profile class matches the
2096 : * application requirements; the spec provides no guidance, but it's pretty
2097 : * weird if the profile is not scanner ('scnr'), monitor ('mntr'), printer
2098 : * ('prtr') or 'spac' (for generic color spaces). Issue a warning in these
2099 : * cases. Issue an error for device link or abstract profiles - these don't
2100 : * contain the records necessary to transform the color-space to anything
2101 : * other than the target device (and not even that for an abstract profile).
2102 : * Profiles of these classes may not be embedded in images.
2103 : */
2104 0 : temp = png_get_uint_32(profile+12); /* profile/device class */
2105 0 : switch (temp)
2106 : {
2107 : case 0x73636e72: /* 'scnr' */
2108 : case 0x6d6e7472: /* 'mntr' */
2109 : case 0x70727472: /* 'prtr' */
2110 : case 0x73706163: /* 'spac' */
2111 : /* All supported */
2112 0 : break;
2113 :
2114 : case 0x61627374: /* 'abst' */
2115 : /* May not be embedded in an image */
2116 0 : return png_icc_profile_error(png_ptr, colorspace, name, temp,
2117 : "invalid embedded Abstract ICC profile");
2118 :
2119 : case 0x6c696e6b: /* 'link' */
2120 : /* DeviceLink profiles cannot be interpreted in a non-device specific
2121 : * fashion, if an app uses the AToB0Tag in the profile the results are
2122 : * undefined unless the result is sent to the intended device,
2123 : * therefore a DeviceLink profile should not be found embedded in a
2124 : * PNG.
2125 : */
2126 0 : return png_icc_profile_error(png_ptr, colorspace, name, temp,
2127 : "unexpected DeviceLink ICC profile class");
2128 :
2129 : case 0x6e6d636c: /* 'nmcl' */
2130 : /* A NamedColor profile is also device specific, however it doesn't
2131 : * contain an AToB0 tag that is open to misinterpretation. Almost
2132 : * certainly it will fail the tests below.
2133 : */
2134 0 : (void)png_icc_profile_error(png_ptr, NULL, name, temp,
2135 : "unexpected NamedColor ICC profile class");
2136 0 : break;
2137 :
2138 : default:
2139 : /* To allow for future enhancements to the profile accept unrecognized
2140 : * profile classes with a warning, these then hit the test below on the
2141 : * tag content to ensure they are backward compatible with one of the
2142 : * understood profiles.
2143 : */
2144 0 : (void)png_icc_profile_error(png_ptr, NULL, name, temp,
2145 : "unrecognized ICC profile class");
2146 0 : break;
2147 : }
2148 :
2149 : /* For any profile other than a device link one the PCS must be encoded
2150 : * either in XYZ or Lab.
2151 : */
2152 0 : temp = png_get_uint_32(profile+20);
2153 0 : switch (temp)
2154 : {
2155 : case 0x58595a20: /* 'XYZ ' */
2156 : case 0x4c616220: /* 'Lab ' */
2157 0 : break;
2158 :
2159 : default:
2160 0 : return png_icc_profile_error(png_ptr, colorspace, name, temp,
2161 : "unexpected ICC PCS encoding");
2162 : }
2163 :
2164 0 : return 1;
2165 : }
2166 :
2167 : int /* PRIVATE */
2168 0 : png_icc_check_tag_table(png_const_structrp png_ptr, png_colorspacerp colorspace,
2169 : png_const_charp name, png_uint_32 profile_length,
2170 : png_const_bytep profile /* header plus whole tag table */)
2171 : {
2172 0 : png_uint_32 tag_count = png_get_uint_32(profile+128);
2173 : png_uint_32 itag;
2174 0 : png_const_bytep tag = profile+132; /* The first tag */
2175 :
2176 : /* First scan all the tags in the table and add bits to the icc_info value
2177 : * (temporarily in 'tags').
2178 : */
2179 0 : for (itag=0; itag < tag_count; ++itag, tag += 12)
2180 : {
2181 0 : png_uint_32 tag_id = png_get_uint_32(tag+0);
2182 0 : png_uint_32 tag_start = png_get_uint_32(tag+4); /* must be aligned */
2183 0 : png_uint_32 tag_length = png_get_uint_32(tag+8);/* not padded */
2184 :
2185 : /* The ICC specification does not exclude zero length tags, therefore the
2186 : * start might actually be anywhere if there is no data, but this would be
2187 : * a clear abuse of the intent of the standard so the start is checked for
2188 : * being in range. All defined tag types have an 8 byte header - a 4 byte
2189 : * type signature then 0.
2190 : */
2191 0 : if ((tag_start & 3) != 0)
2192 : {
2193 : /* CNHP730S.icc shipped with Microsoft Windows 64 violates this, it is
2194 : * only a warning here because libpng does not care about the
2195 : * alignment.
2196 : */
2197 0 : (void)png_icc_profile_error(png_ptr, NULL, name, tag_id,
2198 : "ICC profile tag start not a multiple of 4");
2199 : }
2200 :
2201 : /* This is a hard error; potentially it can cause read outside the
2202 : * profile.
2203 : */
2204 0 : if (tag_start > profile_length || tag_length > profile_length - tag_start)
2205 0 : return png_icc_profile_error(png_ptr, colorspace, name, tag_id,
2206 : "ICC profile tag outside profile");
2207 : }
2208 :
2209 0 : return 1; /* success, maybe with warnings */
2210 : }
2211 :
2212 : #ifdef PNG_sRGB_SUPPORTED
2213 : #if PNG_sRGB_PROFILE_CHECKS >= 0
2214 : /* Information about the known ICC sRGB profiles */
2215 : static const struct
2216 : {
2217 : png_uint_32 adler, crc, length;
2218 : png_uint_32 md5[4];
2219 : png_byte have_md5;
2220 : png_byte is_broken;
2221 : png_uint_16 intent;
2222 :
2223 : # define PNG_MD5(a,b,c,d) { a, b, c, d }, (a!=0)||(b!=0)||(c!=0)||(d!=0)
2224 : # define PNG_ICC_CHECKSUM(adler, crc, md5, intent, broke, date, length, fname)\
2225 : { adler, crc, length, md5, broke, intent },
2226 :
2227 : } png_sRGB_checks[] =
2228 : {
2229 : /* This data comes from contrib/tools/checksum-icc run on downloads of
2230 : * all four ICC sRGB profiles from www.color.org.
2231 : */
2232 : /* adler32, crc32, MD5[4], intent, date, length, file-name */
2233 : PNG_ICC_CHECKSUM(0x0a3fd9f6, 0x3b8772b9,
2234 : PNG_MD5(0x29f83dde, 0xaff255ae, 0x7842fae4, 0xca83390d), 0, 0,
2235 : "2009/03/27 21:36:31", 3048, "sRGB_IEC61966-2-1_black_scaled.icc")
2236 :
2237 : /* ICC sRGB v2 perceptual no black-compensation: */
2238 : PNG_ICC_CHECKSUM(0x4909e5e1, 0x427ebb21,
2239 : PNG_MD5(0xc95bd637, 0xe95d8a3b, 0x0df38f99, 0xc1320389), 1, 0,
2240 : "2009/03/27 21:37:45", 3052, "sRGB_IEC61966-2-1_no_black_scaling.icc")
2241 :
2242 : PNG_ICC_CHECKSUM(0xfd2144a1, 0x306fd8ae,
2243 : PNG_MD5(0xfc663378, 0x37e2886b, 0xfd72e983, 0x8228f1b8), 0, 0,
2244 : "2009/08/10 17:28:01", 60988, "sRGB_v4_ICC_preference_displayclass.icc")
2245 :
2246 : /* ICC sRGB v4 perceptual */
2247 : PNG_ICC_CHECKSUM(0x209c35d2, 0xbbef7812,
2248 : PNG_MD5(0x34562abf, 0x994ccd06, 0x6d2c5721, 0xd0d68c5d), 0, 0,
2249 : "2007/07/25 00:05:37", 60960, "sRGB_v4_ICC_preference.icc")
2250 :
2251 : /* The following profiles have no known MD5 checksum. If there is a match
2252 : * on the (empty) MD5 the other fields are used to attempt a match and
2253 : * a warning is produced. The first two of these profiles have a 'cprt' tag
2254 : * which suggests that they were also made by Hewlett Packard.
2255 : */
2256 : PNG_ICC_CHECKSUM(0xa054d762, 0x5d5129ce,
2257 : PNG_MD5(0x00000000, 0x00000000, 0x00000000, 0x00000000), 1, 0,
2258 : "2004/07/21 18:57:42", 3024, "sRGB_IEC61966-2-1_noBPC.icc")
2259 :
2260 : /* This is a 'mntr' (display) profile with a mediaWhitePointTag that does not
2261 : * match the D50 PCS illuminant in the header (it is in fact the D65 values,
2262 : * so the white point is recorded as the un-adapted value.) The profiles
2263 : * below only differ in one byte - the intent - and are basically the same as
2264 : * the previous profile except for the mediaWhitePointTag error and a missing
2265 : * chromaticAdaptationTag.
2266 : */
2267 : PNG_ICC_CHECKSUM(0xf784f3fb, 0x182ea552,
2268 : PNG_MD5(0x00000000, 0x00000000, 0x00000000, 0x00000000), 0, 1/*broken*/,
2269 : "1998/02/09 06:49:00", 3144, "HP-Microsoft sRGB v2 perceptual")
2270 :
2271 : PNG_ICC_CHECKSUM(0x0398f3fc, 0xf29e526d,
2272 : PNG_MD5(0x00000000, 0x00000000, 0x00000000, 0x00000000), 1, 1/*broken*/,
2273 : "1998/02/09 06:49:00", 3144, "HP-Microsoft sRGB v2 media-relative")
2274 : };
2275 :
2276 : static int
2277 : png_compare_ICC_profile_with_sRGB(png_const_structrp png_ptr,
2278 : png_const_bytep profile, uLong adler)
2279 : {
2280 : /* The quick check is to verify just the MD5 signature and trust the
2281 : * rest of the data. Because the profile has already been verified for
2282 : * correctness this is safe. png_colorspace_set_sRGB will check the 'intent'
2283 : * field too, so if the profile has been edited with an intent not defined
2284 : * by sRGB (but maybe defined by a later ICC specification) the read of
2285 : * the profile will fail at that point.
2286 : */
2287 :
2288 : png_uint_32 length = 0;
2289 : png_uint_32 intent = 0x10000; /* invalid */
2290 : #if PNG_sRGB_PROFILE_CHECKS > 1
2291 : uLong crc = 0; /* the value for 0 length data */
2292 : #endif
2293 : unsigned int i;
2294 :
2295 : #ifdef PNG_SET_OPTION_SUPPORTED
2296 : /* First see if PNG_SKIP_sRGB_CHECK_PROFILE has been set to "on" */
2297 : if (((png_ptr->options >> PNG_SKIP_sRGB_CHECK_PROFILE) & 3) ==
2298 : PNG_OPTION_ON)
2299 : return 0;
2300 : #endif
2301 :
2302 : for (i=0; i < (sizeof png_sRGB_checks) / (sizeof png_sRGB_checks[0]); ++i)
2303 : {
2304 : if (png_get_uint_32(profile+84) == png_sRGB_checks[i].md5[0] &&
2305 : png_get_uint_32(profile+88) == png_sRGB_checks[i].md5[1] &&
2306 : png_get_uint_32(profile+92) == png_sRGB_checks[i].md5[2] &&
2307 : png_get_uint_32(profile+96) == png_sRGB_checks[i].md5[3])
2308 : {
2309 : /* This may be one of the old HP profiles without an MD5, in that
2310 : * case we can only use the length and Adler32 (note that these
2311 : * are not used by default if there is an MD5!)
2312 : */
2313 : # if PNG_sRGB_PROFILE_CHECKS == 0
2314 : if (png_sRGB_checks[i].have_md5 != 0)
2315 : return 1+png_sRGB_checks[i].is_broken;
2316 : # endif
2317 :
2318 : /* Profile is unsigned or more checks have been configured in. */
2319 : if (length == 0)
2320 : {
2321 : length = png_get_uint_32(profile);
2322 : intent = png_get_uint_32(profile+64);
2323 : }
2324 :
2325 : /* Length *and* intent must match */
2326 : if (length == (png_uint_32) png_sRGB_checks[i].length &&
2327 : intent == (png_uint_32) png_sRGB_checks[i].intent)
2328 : {
2329 : /* Now calculate the adler32 if not done already. */
2330 : if (adler == 0)
2331 : {
2332 : adler = adler32(0, NULL, 0);
2333 : adler = adler32(adler, profile, length);
2334 : }
2335 :
2336 : if (adler == png_sRGB_checks[i].adler)
2337 : {
2338 : /* These basic checks suggest that the data has not been
2339 : * modified, but if the check level is more than 1 perform
2340 : * our own crc32 checksum on the data.
2341 : */
2342 : # if PNG_sRGB_PROFILE_CHECKS > 1
2343 : if (crc == 0)
2344 : {
2345 : crc = crc32(0, NULL, 0);
2346 : crc = crc32(crc, profile, length);
2347 : }
2348 :
2349 : /* So this check must pass for the 'return' below to happen.
2350 : */
2351 : if (crc == png_sRGB_checks[i].crc)
2352 : # endif
2353 : {
2354 : if (png_sRGB_checks[i].is_broken != 0)
2355 : {
2356 : /* These profiles are known to have bad data that may cause
2357 : * problems if they are used, therefore attempt to
2358 : * discourage their use, skip the 'have_md5' warning below,
2359 : * which is made irrelevant by this error.
2360 : */
2361 : png_chunk_report(png_ptr, "known incorrect sRGB profile",
2362 : PNG_CHUNK_ERROR);
2363 : }
2364 :
2365 : /* Warn that this being done; this isn't even an error since
2366 : * the profile is perfectly valid, but it would be nice if
2367 : * people used the up-to-date ones.
2368 : */
2369 : else if (png_sRGB_checks[i].have_md5 == 0)
2370 : {
2371 : png_chunk_report(png_ptr,
2372 : "out-of-date sRGB profile with no signature",
2373 : PNG_CHUNK_WARNING);
2374 : }
2375 :
2376 : return 1+png_sRGB_checks[i].is_broken;
2377 : }
2378 : }
2379 :
2380 : # if PNG_sRGB_PROFILE_CHECKS > 0
2381 : /* The signature matched, but the profile had been changed in some
2382 : * way. This probably indicates a data error or uninformed hacking.
2383 : * Fall through to "no match".
2384 : */
2385 : png_chunk_report(png_ptr,
2386 : "Not recognizing known sRGB profile that has been edited",
2387 : PNG_CHUNK_WARNING);
2388 : break;
2389 : # endif
2390 : }
2391 : }
2392 : }
2393 :
2394 : return 0; /* no match */
2395 : }
2396 :
2397 : void /* PRIVATE */
2398 : png_icc_set_sRGB(png_const_structrp png_ptr,
2399 : png_colorspacerp colorspace, png_const_bytep profile, uLong adler)
2400 : {
2401 : /* Is this profile one of the known ICC sRGB profiles? If it is, just set
2402 : * the sRGB information.
2403 : */
2404 : if (png_compare_ICC_profile_with_sRGB(png_ptr, profile, adler) != 0)
2405 : (void)png_colorspace_set_sRGB(png_ptr, colorspace,
2406 : (int)/*already checked*/png_get_uint_32(profile+64));
2407 : }
2408 : #endif /* PNG_sRGB_PROFILE_CHECKS >= 0 */
2409 : #endif /* sRGB */
2410 :
2411 : int /* PRIVATE */
2412 0 : png_colorspace_set_ICC(png_const_structrp png_ptr, png_colorspacerp colorspace,
2413 : png_const_charp name, png_uint_32 profile_length, png_const_bytep profile,
2414 : int color_type)
2415 : {
2416 0 : if ((colorspace->flags & PNG_COLORSPACE_INVALID) != 0)
2417 0 : return 0;
2418 :
2419 0 : if (icc_check_length(png_ptr, colorspace, name, profile_length) != 0 &&
2420 0 : png_icc_check_header(png_ptr, colorspace, name, profile_length, profile,
2421 0 : color_type) != 0 &&
2422 0 : png_icc_check_tag_table(png_ptr, colorspace, name, profile_length,
2423 : profile) != 0)
2424 : {
2425 : # if defined(PNG_sRGB_SUPPORTED) && PNG_sRGB_PROFILE_CHECKS >= 0
2426 : /* If no sRGB support, don't try storing sRGB information */
2427 : png_icc_set_sRGB(png_ptr, colorspace, profile, 0);
2428 : # endif
2429 0 : return 1;
2430 : }
2431 :
2432 : /* Failure case */
2433 0 : return 0;
2434 : }
2435 : #endif /* iCCP */
2436 :
2437 : #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
2438 : void /* PRIVATE */
2439 : png_colorspace_set_rgb_coefficients(png_structrp png_ptr)
2440 : {
2441 : /* Set the rgb_to_gray coefficients from the colorspace. */
2442 : if (png_ptr->rgb_to_gray_coefficients_set == 0 &&
2443 : (png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
2444 : {
2445 : /* png_set_background has not been called, get the coefficients from the Y
2446 : * values of the colorspace colorants.
2447 : */
2448 : png_fixed_point r = png_ptr->colorspace.end_points_XYZ.red_Y;
2449 : png_fixed_point g = png_ptr->colorspace.end_points_XYZ.green_Y;
2450 : png_fixed_point b = png_ptr->colorspace.end_points_XYZ.blue_Y;
2451 : png_fixed_point total = r+g+b;
2452 :
2453 : if (total > 0 &&
2454 : r >= 0 && png_muldiv(&r, r, 32768, total) && r >= 0 && r <= 32768 &&
2455 : g >= 0 && png_muldiv(&g, g, 32768, total) && g >= 0 && g <= 32768 &&
2456 : b >= 0 && png_muldiv(&b, b, 32768, total) && b >= 0 && b <= 32768 &&
2457 : r+g+b <= 32769)
2458 : {
2459 : /* We allow 0 coefficients here. r+g+b may be 32769 if two or
2460 : * all of the coefficients were rounded up. Handle this by
2461 : * reducing the *largest* coefficient by 1; this matches the
2462 : * approach used for the default coefficients in pngrtran.c
2463 : */
2464 : int add = 0;
2465 :
2466 : if (r+g+b > 32768)
2467 : add = -1;
2468 : else if (r+g+b < 32768)
2469 : add = 1;
2470 :
2471 : if (add != 0)
2472 : {
2473 : if (g >= r && g >= b)
2474 : g += add;
2475 : else if (r >= g && r >= b)
2476 : r += add;
2477 : else
2478 : b += add;
2479 : }
2480 :
2481 : /* Check for an internal error. */
2482 : if (r+g+b != 32768)
2483 : png_error(png_ptr,
2484 : "internal error handling cHRM coefficients");
2485 :
2486 : else
2487 : {
2488 : png_ptr->rgb_to_gray_red_coeff = (png_uint_16)r;
2489 : png_ptr->rgb_to_gray_green_coeff = (png_uint_16)g;
2490 : }
2491 : }
2492 :
2493 : /* This is a png_error at present even though it could be ignored -
2494 : * it should never happen, but it is important that if it does, the
2495 : * bug is fixed.
2496 : */
2497 : else
2498 : png_error(png_ptr, "internal error handling cHRM->XYZ");
2499 : }
2500 : }
2501 : #endif /* READ_RGB_TO_GRAY */
2502 :
2503 : #endif /* COLORSPACE */
2504 :
2505 : #ifdef __GNUC__
2506 : /* This exists solely to work round a warning from GNU C. */
2507 : static int /* PRIVATE */
2508 62 : png_gt(size_t a, size_t b)
2509 : {
2510 62 : return a > b;
2511 : }
2512 : #else
2513 : # define png_gt(a,b) ((a) > (b))
2514 : #endif
2515 :
2516 : void /* PRIVATE */
2517 62 : png_check_IHDR(png_const_structrp png_ptr,
2518 : png_uint_32 width, png_uint_32 height, int bit_depth,
2519 : int color_type, int interlace_type, int compression_type,
2520 : int filter_type)
2521 : {
2522 62 : int error = 0;
2523 :
2524 : /* Check for width and height valid values */
2525 62 : if (width == 0)
2526 : {
2527 0 : png_warning(png_ptr, "Image width is zero in IHDR");
2528 0 : error = 1;
2529 : }
2530 :
2531 62 : if (width > PNG_UINT_31_MAX)
2532 : {
2533 0 : png_warning(png_ptr, "Invalid image width in IHDR");
2534 0 : error = 1;
2535 : }
2536 :
2537 62 : if (png_gt(((width + 7) & (~7U)),
2538 : ((PNG_SIZE_MAX
2539 : - 48 /* big_row_buf hack */
2540 : - 1) /* filter byte */
2541 : / 8) /* 8-byte RGBA pixels */
2542 : - 1)) /* extra max_pixel_depth pad */
2543 : {
2544 : /* The size of the row must be within the limits of this architecture.
2545 : * Because the read code can perform arbitrary transformations the
2546 : * maximum size is checked here. Because the code in png_read_start_row
2547 : * adds extra space "for safety's sake" in several places a conservative
2548 : * limit is used here.
2549 : *
2550 : * NOTE: it would be far better to check the size that is actually used,
2551 : * but the effect in the real world is minor and the changes are more
2552 : * extensive, therefore much more dangerous and much more difficult to
2553 : * write in a way that avoids compiler warnings.
2554 : */
2555 0 : png_warning(png_ptr, "Image width is too large for this architecture");
2556 0 : error = 1;
2557 : }
2558 :
2559 : #ifdef PNG_SET_USER_LIMITS_SUPPORTED
2560 62 : if (width > png_ptr->user_width_max)
2561 : #else
2562 : if (width > PNG_USER_WIDTH_MAX)
2563 : #endif
2564 : {
2565 0 : png_warning(png_ptr, "Image width exceeds user limit in IHDR");
2566 0 : error = 1;
2567 : }
2568 :
2569 62 : if (height == 0)
2570 : {
2571 0 : png_warning(png_ptr, "Image height is zero in IHDR");
2572 0 : error = 1;
2573 : }
2574 :
2575 62 : if (height > PNG_UINT_31_MAX)
2576 : {
2577 0 : png_warning(png_ptr, "Invalid image height in IHDR");
2578 0 : error = 1;
2579 : }
2580 :
2581 : #ifdef PNG_SET_USER_LIMITS_SUPPORTED
2582 62 : if (height > png_ptr->user_height_max)
2583 : #else
2584 : if (height > PNG_USER_HEIGHT_MAX)
2585 : #endif
2586 : {
2587 0 : png_warning(png_ptr, "Image height exceeds user limit in IHDR");
2588 0 : error = 1;
2589 : }
2590 :
2591 : /* Check other values */
2592 62 : if (bit_depth != 1 && bit_depth != 2 && bit_depth != 4 &&
2593 0 : bit_depth != 8 && bit_depth != 16)
2594 : {
2595 0 : png_warning(png_ptr, "Invalid bit depth in IHDR");
2596 0 : error = 1;
2597 : }
2598 :
2599 62 : if (color_type < 0 || color_type == 1 ||
2600 62 : color_type == 5 || color_type > 6)
2601 : {
2602 0 : png_warning(png_ptr, "Invalid color type in IHDR");
2603 0 : error = 1;
2604 : }
2605 :
2606 62 : if (((color_type == PNG_COLOR_TYPE_PALETTE) && bit_depth > 8) ||
2607 62 : ((color_type == PNG_COLOR_TYPE_RGB ||
2608 54 : color_type == PNG_COLOR_TYPE_GRAY_ALPHA ||
2609 58 : color_type == PNG_COLOR_TYPE_RGB_ALPHA) && bit_depth < 8))
2610 : {
2611 0 : png_warning(png_ptr, "Invalid color type/bit depth combination in IHDR");
2612 0 : error = 1;
2613 : }
2614 :
2615 62 : if (interlace_type >= PNG_INTERLACE_LAST)
2616 : {
2617 0 : png_warning(png_ptr, "Unknown interlace method in IHDR");
2618 0 : error = 1;
2619 : }
2620 :
2621 62 : if (compression_type != PNG_COMPRESSION_TYPE_BASE)
2622 : {
2623 0 : png_warning(png_ptr, "Unknown compression method in IHDR");
2624 0 : error = 1;
2625 : }
2626 :
2627 : #ifdef PNG_MNG_FEATURES_SUPPORTED
2628 : /* Accept filter_method 64 (intrapixel differencing) only if
2629 : * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
2630 : * 2. Libpng did not read a PNG signature (this filter_method is only
2631 : * used in PNG datastreams that are embedded in MNG datastreams) and
2632 : * 3. The application called png_permit_mng_features with a mask that
2633 : * included PNG_FLAG_MNG_FILTER_64 and
2634 : * 4. The filter_method is 64 and
2635 : * 5. The color_type is RGB or RGBA
2636 : */
2637 : if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) != 0 &&
2638 : png_ptr->mng_features_permitted != 0)
2639 : png_warning(png_ptr, "MNG features are not allowed in a PNG datastream");
2640 :
2641 : if (filter_type != PNG_FILTER_TYPE_BASE)
2642 : {
2643 : if (!((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
2644 : (filter_type == PNG_INTRAPIXEL_DIFFERENCING) &&
2645 : ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) == 0) &&
2646 : (color_type == PNG_COLOR_TYPE_RGB ||
2647 : color_type == PNG_COLOR_TYPE_RGB_ALPHA)))
2648 : {
2649 : png_warning(png_ptr, "Unknown filter method in IHDR");
2650 : error = 1;
2651 : }
2652 :
2653 : if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) != 0)
2654 : {
2655 : png_warning(png_ptr, "Invalid filter method in IHDR");
2656 : error = 1;
2657 : }
2658 : }
2659 :
2660 : #else
2661 62 : if (filter_type != PNG_FILTER_TYPE_BASE)
2662 : {
2663 0 : png_warning(png_ptr, "Unknown filter method in IHDR");
2664 0 : error = 1;
2665 : }
2666 : #endif
2667 :
2668 62 : if (error == 1)
2669 0 : png_error(png_ptr, "Invalid IHDR data");
2670 62 : }
2671 :
2672 : #if defined(PNG_sCAL_SUPPORTED) || defined(PNG_pCAL_SUPPORTED)
2673 : /* ASCII to fp functions */
2674 : /* Check an ASCII formated floating point value, see the more detailed
2675 : * comments in pngpriv.h
2676 : */
2677 : /* The following is used internally to preserve the sticky flags */
2678 : #define png_fp_add(state, flags) ((state) |= (flags))
2679 : #define png_fp_set(state, value) ((state) = (value) | ((state) & PNG_FP_STICKY))
2680 :
2681 : int /* PRIVATE */
2682 : png_check_fp_number(png_const_charp string, png_size_t size, int *statep,
2683 : png_size_tp whereami)
2684 : {
2685 : int state = *statep;
2686 : png_size_t i = *whereami;
2687 :
2688 : while (i < size)
2689 : {
2690 : int type;
2691 : /* First find the type of the next character */
2692 : switch (string[i])
2693 : {
2694 : case 43: type = PNG_FP_SAW_SIGN; break;
2695 : case 45: type = PNG_FP_SAW_SIGN + PNG_FP_NEGATIVE; break;
2696 : case 46: type = PNG_FP_SAW_DOT; break;
2697 : case 48: type = PNG_FP_SAW_DIGIT; break;
2698 : case 49: case 50: case 51: case 52:
2699 : case 53: case 54: case 55: case 56:
2700 : case 57: type = PNG_FP_SAW_DIGIT + PNG_FP_NONZERO; break;
2701 : case 69:
2702 : case 101: type = PNG_FP_SAW_E; break;
2703 : default: goto PNG_FP_End;
2704 : }
2705 :
2706 : /* Now deal with this type according to the current
2707 : * state, the type is arranged to not overlap the
2708 : * bits of the PNG_FP_STATE.
2709 : */
2710 : switch ((state & PNG_FP_STATE) + (type & PNG_FP_SAW_ANY))
2711 : {
2712 : case PNG_FP_INTEGER + PNG_FP_SAW_SIGN:
2713 : if ((state & PNG_FP_SAW_ANY) != 0)
2714 : goto PNG_FP_End; /* not a part of the number */
2715 :
2716 : png_fp_add(state, type);
2717 : break;
2718 :
2719 : case PNG_FP_INTEGER + PNG_FP_SAW_DOT:
2720 : /* Ok as trailer, ok as lead of fraction. */
2721 : if ((state & PNG_FP_SAW_DOT) != 0) /* two dots */
2722 : goto PNG_FP_End;
2723 :
2724 : else if ((state & PNG_FP_SAW_DIGIT) != 0) /* trailing dot? */
2725 : png_fp_add(state, type);
2726 :
2727 : else
2728 : png_fp_set(state, PNG_FP_FRACTION | type);
2729 :
2730 : break;
2731 :
2732 : case PNG_FP_INTEGER + PNG_FP_SAW_DIGIT:
2733 : if ((state & PNG_FP_SAW_DOT) != 0) /* delayed fraction */
2734 : png_fp_set(state, PNG_FP_FRACTION | PNG_FP_SAW_DOT);
2735 :
2736 : png_fp_add(state, type | PNG_FP_WAS_VALID);
2737 :
2738 : break;
2739 :
2740 : case PNG_FP_INTEGER + PNG_FP_SAW_E:
2741 : if ((state & PNG_FP_SAW_DIGIT) == 0)
2742 : goto PNG_FP_End;
2743 :
2744 : png_fp_set(state, PNG_FP_EXPONENT);
2745 :
2746 : break;
2747 :
2748 : /* case PNG_FP_FRACTION + PNG_FP_SAW_SIGN:
2749 : goto PNG_FP_End; ** no sign in fraction */
2750 :
2751 : /* case PNG_FP_FRACTION + PNG_FP_SAW_DOT:
2752 : goto PNG_FP_End; ** Because SAW_DOT is always set */
2753 :
2754 : case PNG_FP_FRACTION + PNG_FP_SAW_DIGIT:
2755 : png_fp_add(state, type | PNG_FP_WAS_VALID);
2756 : break;
2757 :
2758 : case PNG_FP_FRACTION + PNG_FP_SAW_E:
2759 : /* This is correct because the trailing '.' on an
2760 : * integer is handled above - so we can only get here
2761 : * with the sequence ".E" (with no preceding digits).
2762 : */
2763 : if ((state & PNG_FP_SAW_DIGIT) == 0)
2764 : goto PNG_FP_End;
2765 :
2766 : png_fp_set(state, PNG_FP_EXPONENT);
2767 :
2768 : break;
2769 :
2770 : case PNG_FP_EXPONENT + PNG_FP_SAW_SIGN:
2771 : if ((state & PNG_FP_SAW_ANY) != 0)
2772 : goto PNG_FP_End; /* not a part of the number */
2773 :
2774 : png_fp_add(state, PNG_FP_SAW_SIGN);
2775 :
2776 : break;
2777 :
2778 : /* case PNG_FP_EXPONENT + PNG_FP_SAW_DOT:
2779 : goto PNG_FP_End; */
2780 :
2781 : case PNG_FP_EXPONENT + PNG_FP_SAW_DIGIT:
2782 : png_fp_add(state, PNG_FP_SAW_DIGIT | PNG_FP_WAS_VALID);
2783 :
2784 : break;
2785 :
2786 : /* case PNG_FP_EXPONEXT + PNG_FP_SAW_E:
2787 : goto PNG_FP_End; */
2788 :
2789 : default: goto PNG_FP_End; /* I.e. break 2 */
2790 : }
2791 :
2792 : /* The character seems ok, continue. */
2793 : ++i;
2794 : }
2795 :
2796 : PNG_FP_End:
2797 : /* Here at the end, update the state and return the correct
2798 : * return code.
2799 : */
2800 : *statep = state;
2801 : *whereami = i;
2802 :
2803 : return (state & PNG_FP_SAW_DIGIT) != 0;
2804 : }
2805 :
2806 :
2807 : /* The same but for a complete string. */
2808 : int
2809 : png_check_fp_string(png_const_charp string, png_size_t size)
2810 : {
2811 : int state=0;
2812 : png_size_t char_index=0;
2813 :
2814 : if (png_check_fp_number(string, size, &state, &char_index) != 0 &&
2815 : (char_index == size || string[char_index] == 0))
2816 : return state /* must be non-zero - see above */;
2817 :
2818 : return 0; /* i.e. fail */
2819 : }
2820 : #endif /* pCAL || sCAL */
2821 :
2822 : #ifdef PNG_sCAL_SUPPORTED
2823 : # ifdef PNG_FLOATING_POINT_SUPPORTED
2824 : /* Utility used below - a simple accurate power of ten from an integral
2825 : * exponent.
2826 : */
2827 : static double
2828 : png_pow10(int power)
2829 : {
2830 : int recip = 0;
2831 : double d = 1;
2832 :
2833 : /* Handle negative exponent with a reciprocal at the end because
2834 : * 10 is exact whereas .1 is inexact in base 2
2835 : */
2836 : if (power < 0)
2837 : {
2838 : if (power < DBL_MIN_10_EXP) return 0;
2839 : recip = 1, power = -power;
2840 : }
2841 :
2842 : if (power > 0)
2843 : {
2844 : /* Decompose power bitwise. */
2845 : double mult = 10;
2846 : do
2847 : {
2848 : if (power & 1) d *= mult;
2849 : mult *= mult;
2850 : power >>= 1;
2851 : }
2852 : while (power > 0);
2853 :
2854 : if (recip != 0) d = 1/d;
2855 : }
2856 : /* else power is 0 and d is 1 */
2857 :
2858 : return d;
2859 : }
2860 :
2861 : /* Function to format a floating point value in ASCII with a given
2862 : * precision.
2863 : */
2864 : void /* PRIVATE */
2865 : png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,
2866 : double fp, unsigned int precision)
2867 : {
2868 : /* We use standard functions from math.h, but not printf because
2869 : * that would require stdio. The caller must supply a buffer of
2870 : * sufficient size or we will png_error. The tests on size and
2871 : * the space in ascii[] consumed are indicated below.
2872 : */
2873 : if (precision < 1)
2874 : precision = DBL_DIG;
2875 :
2876 : /* Enforce the limit of the implementation precision too. */
2877 : if (precision > DBL_DIG+1)
2878 : precision = DBL_DIG+1;
2879 :
2880 : /* Basic sanity checks */
2881 : if (size >= precision+5) /* See the requirements below. */
2882 : {
2883 : if (fp < 0)
2884 : {
2885 : fp = -fp;
2886 : *ascii++ = 45; /* '-' PLUS 1 TOTAL 1 */
2887 : --size;
2888 : }
2889 :
2890 : if (fp >= DBL_MIN && fp <= DBL_MAX)
2891 : {
2892 : int exp_b10; /* A base 10 exponent */
2893 : double base; /* 10^exp_b10 */
2894 :
2895 : /* First extract a base 10 exponent of the number,
2896 : * the calculation below rounds down when converting
2897 : * from base 2 to base 10 (multiply by log10(2) -
2898 : * 0.3010, but 77/256 is 0.3008, so exp_b10 needs to
2899 : * be increased. Note that the arithmetic shift
2900 : * performs a floor() unlike C arithmetic - using a
2901 : * C multiply would break the following for negative
2902 : * exponents.
2903 : */
2904 : (void)frexp(fp, &exp_b10); /* exponent to base 2 */
2905 :
2906 : exp_b10 = (exp_b10 * 77) >> 8; /* <= exponent to base 10 */
2907 :
2908 : /* Avoid underflow here. */
2909 : base = png_pow10(exp_b10); /* May underflow */
2910 :
2911 : while (base < DBL_MIN || base < fp)
2912 : {
2913 : /* And this may overflow. */
2914 : double test = png_pow10(exp_b10+1);
2915 :
2916 : if (test <= DBL_MAX)
2917 : ++exp_b10, base = test;
2918 :
2919 : else
2920 : break;
2921 : }
2922 :
2923 : /* Normalize fp and correct exp_b10, after this fp is in the
2924 : * range [.1,1) and exp_b10 is both the exponent and the digit
2925 : * *before* which the decimal point should be inserted
2926 : * (starting with 0 for the first digit). Note that this
2927 : * works even if 10^exp_b10 is out of range because of the
2928 : * test on DBL_MAX above.
2929 : */
2930 : fp /= base;
2931 : while (fp >= 1) fp /= 10, ++exp_b10;
2932 :
2933 : /* Because of the code above fp may, at this point, be
2934 : * less than .1, this is ok because the code below can
2935 : * handle the leading zeros this generates, so no attempt
2936 : * is made to correct that here.
2937 : */
2938 :
2939 : {
2940 : unsigned int czero, clead, cdigits;
2941 : char exponent[10];
2942 :
2943 : /* Allow up to two leading zeros - this will not lengthen
2944 : * the number compared to using E-n.
2945 : */
2946 : if (exp_b10 < 0 && exp_b10 > -3) /* PLUS 3 TOTAL 4 */
2947 : {
2948 : czero = (unsigned int)(-exp_b10); /* PLUS 2 digits: TOTAL 3 */
2949 : exp_b10 = 0; /* Dot added below before first output. */
2950 : }
2951 : else
2952 : czero = 0; /* No zeros to add */
2953 :
2954 : /* Generate the digit list, stripping trailing zeros and
2955 : * inserting a '.' before a digit if the exponent is 0.
2956 : */
2957 : clead = czero; /* Count of leading zeros */
2958 : cdigits = 0; /* Count of digits in list. */
2959 :
2960 : do
2961 : {
2962 : double d;
2963 :
2964 : fp *= 10;
2965 : /* Use modf here, not floor and subtract, so that
2966 : * the separation is done in one step. At the end
2967 : * of the loop don't break the number into parts so
2968 : * that the final digit is rounded.
2969 : */
2970 : if (cdigits+czero+1 < precision+clead)
2971 : fp = modf(fp, &d);
2972 :
2973 : else
2974 : {
2975 : d = floor(fp + .5);
2976 :
2977 : if (d > 9)
2978 : {
2979 : /* Rounding up to 10, handle that here. */
2980 : if (czero > 0)
2981 : {
2982 : --czero, d = 1;
2983 : if (cdigits == 0) --clead;
2984 : }
2985 : else
2986 : {
2987 : while (cdigits > 0 && d > 9)
2988 : {
2989 : int ch = *--ascii;
2990 :
2991 : if (exp_b10 != (-1))
2992 : ++exp_b10;
2993 :
2994 : else if (ch == 46)
2995 : {
2996 : ch = *--ascii, ++size;
2997 : /* Advance exp_b10 to '1', so that the
2998 : * decimal point happens after the
2999 : * previous digit.
3000 : */
3001 : exp_b10 = 1;
3002 : }
3003 :
3004 : --cdigits;
3005 : d = ch - 47; /* I.e. 1+(ch-48) */
3006 : }
3007 :
3008 : /* Did we reach the beginning? If so adjust the
3009 : * exponent but take into account the leading
3010 : * decimal point.
3011 : */
3012 : if (d > 9) /* cdigits == 0 */
3013 : {
3014 : if (exp_b10 == (-1))
3015 : {
3016 : /* Leading decimal point (plus zeros?), if
3017 : * we lose the decimal point here it must
3018 : * be reentered below.
3019 : */
3020 : int ch = *--ascii;
3021 :
3022 : if (ch == 46)
3023 : ++size, exp_b10 = 1;
3024 :
3025 : /* Else lost a leading zero, so 'exp_b10' is
3026 : * still ok at (-1)
3027 : */
3028 : }
3029 : else
3030 : ++exp_b10;
3031 :
3032 : /* In all cases we output a '1' */
3033 : d = 1;
3034 : }
3035 : }
3036 : }
3037 : fp = 0; /* Guarantees termination below. */
3038 : }
3039 :
3040 : if (d == 0)
3041 : {
3042 : ++czero;
3043 : if (cdigits == 0) ++clead;
3044 : }
3045 : else
3046 : {
3047 : /* Included embedded zeros in the digit count. */
3048 : cdigits += czero - clead;
3049 : clead = 0;
3050 :
3051 : while (czero > 0)
3052 : {
3053 : /* exp_b10 == (-1) means we just output the decimal
3054 : * place - after the DP don't adjust 'exp_b10' any
3055 : * more!
3056 : */
3057 : if (exp_b10 != (-1))
3058 : {
3059 : if (exp_b10 == 0) *ascii++ = 46, --size;
3060 : /* PLUS 1: TOTAL 4 */
3061 : --exp_b10;
3062 : }
3063 : *ascii++ = 48, --czero;
3064 : }
3065 :
3066 : if (exp_b10 != (-1))
3067 : {
3068 : if (exp_b10 == 0)
3069 : *ascii++ = 46, --size; /* counted above */
3070 :
3071 : --exp_b10;
3072 : }
3073 : *ascii++ = (char)(48 + (int)d), ++cdigits;
3074 : }
3075 : }
3076 : while (cdigits+czero < precision+clead && fp > DBL_MIN);
3077 :
3078 : /* The total output count (max) is now 4+precision */
3079 :
3080 : /* Check for an exponent, if we don't need one we are
3081 : * done and just need to terminate the string. At
3082 : * this point exp_b10==(-1) is effectively if flag - it got
3083 : * to '-1' because of the decrement after outputting
3084 : * the decimal point above (the exponent required is
3085 : * *not* -1!)
3086 : */
3087 : if (exp_b10 >= (-1) && exp_b10 <= 2)
3088 : {
3089 : /* The following only happens if we didn't output the
3090 : * leading zeros above for negative exponent, so this
3091 : * doesn't add to the digit requirement. Note that the
3092 : * two zeros here can only be output if the two leading
3093 : * zeros were *not* output, so this doesn't increase
3094 : * the output count.
3095 : */
3096 : while (--exp_b10 >= 0) *ascii++ = 48;
3097 :
3098 : *ascii = 0;
3099 :
3100 : /* Total buffer requirement (including the '\0') is
3101 : * 5+precision - see check at the start.
3102 : */
3103 : return;
3104 : }
3105 :
3106 : /* Here if an exponent is required, adjust size for
3107 : * the digits we output but did not count. The total
3108 : * digit output here so far is at most 1+precision - no
3109 : * decimal point and no leading or trailing zeros have
3110 : * been output.
3111 : */
3112 : size -= cdigits;
3113 :
3114 : *ascii++ = 69, --size; /* 'E': PLUS 1 TOTAL 2+precision */
3115 :
3116 : /* The following use of an unsigned temporary avoids ambiguities in
3117 : * the signed arithmetic on exp_b10 and permits GCC at least to do
3118 : * better optimization.
3119 : */
3120 : {
3121 : unsigned int uexp_b10;
3122 :
3123 : if (exp_b10 < 0)
3124 : {
3125 : *ascii++ = 45, --size; /* '-': PLUS 1 TOTAL 3+precision */
3126 : uexp_b10 = (unsigned int)(-exp_b10);
3127 : }
3128 :
3129 : else
3130 : uexp_b10 = (unsigned int)exp_b10;
3131 :
3132 : cdigits = 0;
3133 :
3134 : while (uexp_b10 > 0)
3135 : {
3136 : exponent[cdigits++] = (char)(48 + uexp_b10 % 10);
3137 : uexp_b10 /= 10;
3138 : }
3139 : }
3140 :
3141 : /* Need another size check here for the exponent digits, so
3142 : * this need not be considered above.
3143 : */
3144 : if (size > cdigits)
3145 : {
3146 : while (cdigits > 0) *ascii++ = exponent[--cdigits];
3147 :
3148 : *ascii = 0;
3149 :
3150 : return;
3151 : }
3152 : }
3153 : }
3154 : else if (!(fp >= DBL_MIN))
3155 : {
3156 : *ascii++ = 48; /* '0' */
3157 : *ascii = 0;
3158 : return;
3159 : }
3160 : else
3161 : {
3162 : *ascii++ = 105; /* 'i' */
3163 : *ascii++ = 110; /* 'n' */
3164 : *ascii++ = 102; /* 'f' */
3165 : *ascii = 0;
3166 : return;
3167 : }
3168 : }
3169 :
3170 : /* Here on buffer too small. */
3171 : png_error(png_ptr, "ASCII conversion buffer too small");
3172 : }
3173 :
3174 : # endif /* FLOATING_POINT */
3175 :
3176 : # ifdef PNG_FIXED_POINT_SUPPORTED
3177 : /* Function to format a fixed point value in ASCII.
3178 : */
3179 : void /* PRIVATE */
3180 : png_ascii_from_fixed(png_const_structrp png_ptr, png_charp ascii,
3181 : png_size_t size, png_fixed_point fp)
3182 : {
3183 : /* Require space for 10 decimal digits, a decimal point, a minus sign and a
3184 : * trailing \0, 13 characters:
3185 : */
3186 : if (size > 12)
3187 : {
3188 : png_uint_32 num;
3189 :
3190 : /* Avoid overflow here on the minimum integer. */
3191 : if (fp < 0)
3192 : *ascii++ = 45, num = (png_uint_32)(-fp);
3193 : else
3194 : num = (png_uint_32)fp;
3195 :
3196 : if (num <= 0x80000000) /* else overflowed */
3197 : {
3198 : unsigned int ndigits = 0, first = 16 /* flag value */;
3199 : char digits[10];
3200 :
3201 : while (num)
3202 : {
3203 : /* Split the low digit off num: */
3204 : unsigned int tmp = num/10;
3205 : num -= tmp*10;
3206 : digits[ndigits++] = (char)(48 + num);
3207 : /* Record the first non-zero digit, note that this is a number
3208 : * starting at 1, it's not actually the array index.
3209 : */
3210 : if (first == 16 && num > 0)
3211 : first = ndigits;
3212 : num = tmp;
3213 : }
3214 :
3215 : if (ndigits > 0)
3216 : {
3217 : while (ndigits > 5) *ascii++ = digits[--ndigits];
3218 : /* The remaining digits are fractional digits, ndigits is '5' or
3219 : * smaller at this point. It is certainly not zero. Check for a
3220 : * non-zero fractional digit:
3221 : */
3222 : if (first <= 5)
3223 : {
3224 : unsigned int i;
3225 : *ascii++ = 46; /* decimal point */
3226 : /* ndigits may be <5 for small numbers, output leading zeros
3227 : * then ndigits digits to first:
3228 : */
3229 : i = 5;
3230 : while (ndigits < i) *ascii++ = 48, --i;
3231 : while (ndigits >= first) *ascii++ = digits[--ndigits];
3232 : /* Don't output the trailing zeros! */
3233 : }
3234 : }
3235 : else
3236 : *ascii++ = 48;
3237 :
3238 : /* And null terminate the string: */
3239 : *ascii = 0;
3240 : return;
3241 : }
3242 : }
3243 :
3244 : /* Here on buffer too small. */
3245 : png_error(png_ptr, "ASCII conversion buffer too small");
3246 : }
3247 : # endif /* FIXED_POINT */
3248 : #endif /* SCAL */
3249 :
3250 : #if defined(PNG_FLOATING_POINT_SUPPORTED) && \
3251 : !defined(PNG_FIXED_POINT_MACRO_SUPPORTED) && \
3252 : (defined(PNG_gAMA_SUPPORTED) || defined(PNG_cHRM_SUPPORTED) || \
3253 : defined(PNG_sCAL_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) || \
3254 : defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)) || \
3255 : (defined(PNG_sCAL_SUPPORTED) && \
3256 : defined(PNG_FLOATING_ARITHMETIC_SUPPORTED))
3257 : png_fixed_point
3258 0 : png_fixed(png_const_structrp png_ptr, double fp, png_const_charp text)
3259 : {
3260 0 : double r = floor(100000 * fp + .5);
3261 :
3262 0 : if (r > 2147483647. || r < -2147483648.)
3263 0 : png_fixed_error(png_ptr, text);
3264 :
3265 : # ifndef PNG_ERROR_TEXT_SUPPORTED
3266 : PNG_UNUSED(text)
3267 : # endif
3268 :
3269 0 : return (png_fixed_point)r;
3270 : }
3271 : #endif
3272 :
3273 : #if defined(PNG_GAMMA_SUPPORTED) || defined(PNG_COLORSPACE_SUPPORTED) ||\
3274 : defined(PNG_INCH_CONVERSIONS_SUPPORTED) || defined(PNG_READ_pHYs_SUPPORTED)
3275 : /* muldiv functions */
3276 : /* This API takes signed arguments and rounds the result to the nearest
3277 : * integer (or, for a fixed point number - the standard argument - to
3278 : * the nearest .00001). Overflow and divide by zero are signalled in
3279 : * the result, a boolean - true on success, false on overflow.
3280 : */
3281 : int
3282 23 : png_muldiv(png_fixed_point_p res, png_fixed_point a, png_int_32 times,
3283 : png_int_32 divisor)
3284 : {
3285 : /* Return a * times / divisor, rounded. */
3286 23 : if (divisor != 0)
3287 : {
3288 23 : if (a == 0 || times == 0)
3289 : {
3290 0 : *res = 0;
3291 0 : return 1;
3292 : }
3293 : else
3294 : {
3295 : #ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
3296 23 : double r = a;
3297 23 : r *= times;
3298 23 : r /= divisor;
3299 23 : r = floor(r+.5);
3300 :
3301 : /* A png_fixed_point is a 32-bit integer. */
3302 23 : if (r <= 2147483647. && r >= -2147483648.)
3303 : {
3304 23 : *res = (png_fixed_point)r;
3305 23 : return 1;
3306 : }
3307 : #else
3308 : int negative = 0;
3309 : png_uint_32 A, T, D;
3310 : png_uint_32 s16, s32, s00;
3311 :
3312 : if (a < 0)
3313 : negative = 1, A = -a;
3314 : else
3315 : A = a;
3316 :
3317 : if (times < 0)
3318 : negative = !negative, T = -times;
3319 : else
3320 : T = times;
3321 :
3322 : if (divisor < 0)
3323 : negative = !negative, D = -divisor;
3324 : else
3325 : D = divisor;
3326 :
3327 : /* Following can't overflow because the arguments only
3328 : * have 31 bits each, however the result may be 32 bits.
3329 : */
3330 : s16 = (A >> 16) * (T & 0xffff) +
3331 : (A & 0xffff) * (T >> 16);
3332 : /* Can't overflow because the a*times bit is only 30
3333 : * bits at most.
3334 : */
3335 : s32 = (A >> 16) * (T >> 16) + (s16 >> 16);
3336 : s00 = (A & 0xffff) * (T & 0xffff);
3337 :
3338 : s16 = (s16 & 0xffff) << 16;
3339 : s00 += s16;
3340 :
3341 : if (s00 < s16)
3342 : ++s32; /* carry */
3343 :
3344 : if (s32 < D) /* else overflow */
3345 : {
3346 : /* s32.s00 is now the 64-bit product, do a standard
3347 : * division, we know that s32 < D, so the maximum
3348 : * required shift is 31.
3349 : */
3350 : int bitshift = 32;
3351 : png_fixed_point result = 0; /* NOTE: signed */
3352 :
3353 : while (--bitshift >= 0)
3354 : {
3355 : png_uint_32 d32, d00;
3356 :
3357 : if (bitshift > 0)
3358 : d32 = D >> (32-bitshift), d00 = D << bitshift;
3359 :
3360 : else
3361 : d32 = 0, d00 = D;
3362 :
3363 : if (s32 > d32)
3364 : {
3365 : if (s00 < d00) --s32; /* carry */
3366 : s32 -= d32, s00 -= d00, result += 1<<bitshift;
3367 : }
3368 :
3369 : else
3370 : if (s32 == d32 && s00 >= d00)
3371 : s32 = 0, s00 -= d00, result += 1<<bitshift;
3372 : }
3373 :
3374 : /* Handle the rounding. */
3375 : if (s00 >= (D >> 1))
3376 : ++result;
3377 :
3378 : if (negative != 0)
3379 : result = -result;
3380 :
3381 : /* Check for overflow. */
3382 : if ((negative != 0 && result <= 0) ||
3383 : (negative == 0 && result >= 0))
3384 : {
3385 : *res = result;
3386 : return 1;
3387 : }
3388 : }
3389 : #endif
3390 : }
3391 : }
3392 :
3393 0 : return 0;
3394 : }
3395 : #endif /* READ_GAMMA || INCH_CONVERSIONS */
3396 :
3397 : #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_INCH_CONVERSIONS_SUPPORTED)
3398 : /* The following is for when the caller doesn't much care about the
3399 : * result.
3400 : */
3401 : png_fixed_point
3402 0 : png_muldiv_warn(png_const_structrp png_ptr, png_fixed_point a, png_int_32 times,
3403 : png_int_32 divisor)
3404 : {
3405 : png_fixed_point result;
3406 :
3407 0 : if (png_muldiv(&result, a, times, divisor) != 0)
3408 0 : return result;
3409 :
3410 0 : png_warning(png_ptr, "fixed point overflow ignored");
3411 0 : return 0;
3412 : }
3413 : #endif
3414 :
3415 : #ifdef PNG_GAMMA_SUPPORTED /* more fixed point functions for gamma */
3416 : /* Calculate a reciprocal, return 0 on div-by-zero or overflow. */
3417 : png_fixed_point
3418 8 : png_reciprocal(png_fixed_point a)
3419 : {
3420 : #ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
3421 8 : double r = floor(1E10/a+.5);
3422 :
3423 8 : if (r <= 2147483647. && r >= -2147483648.)
3424 8 : return (png_fixed_point)r;
3425 : #else
3426 : png_fixed_point res;
3427 :
3428 : if (png_muldiv(&res, 100000, 100000, a) != 0)
3429 : return res;
3430 : #endif
3431 :
3432 0 : return 0; /* error/overflow */
3433 : }
3434 :
3435 : /* This is the shared test on whether a gamma value is 'significant' - whether
3436 : * it is worth doing gamma correction.
3437 : */
3438 : int /* PRIVATE */
3439 23 : png_gamma_significant(png_fixed_point gamma_val)
3440 : {
3441 23 : return gamma_val < PNG_FP_1 - PNG_GAMMA_THRESHOLD_FIXED ||
3442 : gamma_val > PNG_FP_1 + PNG_GAMMA_THRESHOLD_FIXED;
3443 : }
3444 : #endif
3445 :
3446 : #ifdef PNG_READ_GAMMA_SUPPORTED
3447 : #ifdef PNG_16BIT_SUPPORTED
3448 : /* A local convenience routine. */
3449 : static png_fixed_point
3450 0 : png_product2(png_fixed_point a, png_fixed_point b)
3451 : {
3452 : /* The required result is 1/a * 1/b; the following preserves accuracy. */
3453 : #ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
3454 0 : double r = a * 1E-5;
3455 0 : r *= b;
3456 0 : r = floor(r+.5);
3457 :
3458 0 : if (r <= 2147483647. && r >= -2147483648.)
3459 0 : return (png_fixed_point)r;
3460 : #else
3461 : png_fixed_point res;
3462 :
3463 : if (png_muldiv(&res, a, b, 100000) != 0)
3464 : return res;
3465 : #endif
3466 :
3467 0 : return 0; /* overflow */
3468 : }
3469 : #endif /* 16BIT */
3470 :
3471 : /* The inverse of the above. */
3472 : png_fixed_point
3473 0 : png_reciprocal2(png_fixed_point a, png_fixed_point b)
3474 : {
3475 : /* The required result is 1/a * 1/b; the following preserves accuracy. */
3476 : #ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
3477 0 : if (a != 0 && b != 0)
3478 : {
3479 0 : double r = 1E15/a;
3480 0 : r /= b;
3481 0 : r = floor(r+.5);
3482 :
3483 0 : if (r <= 2147483647. && r >= -2147483648.)
3484 0 : return (png_fixed_point)r;
3485 : }
3486 : #else
3487 : /* This may overflow because the range of png_fixed_point isn't symmetric,
3488 : * but this API is only used for the product of file and screen gamma so it
3489 : * doesn't matter that the smallest number it can produce is 1/21474, not
3490 : * 1/100000
3491 : */
3492 : png_fixed_point res = png_product2(a, b);
3493 :
3494 : if (res != 0)
3495 : return png_reciprocal(res);
3496 : #endif
3497 :
3498 0 : return 0; /* overflow */
3499 : }
3500 : #endif /* READ_GAMMA */
3501 :
3502 : #ifdef PNG_READ_GAMMA_SUPPORTED /* gamma table code */
3503 : #ifndef PNG_FLOATING_ARITHMETIC_SUPPORTED
3504 : /* Fixed point gamma.
3505 : *
3506 : * The code to calculate the tables used below can be found in the shell script
3507 : * contrib/tools/intgamma.sh
3508 : *
3509 : * To calculate gamma this code implements fast log() and exp() calls using only
3510 : * fixed point arithmetic. This code has sufficient precision for either 8-bit
3511 : * or 16-bit sample values.
3512 : *
3513 : * The tables used here were calculated using simple 'bc' programs, but C double
3514 : * precision floating point arithmetic would work fine.
3515 : *
3516 : * 8-bit log table
3517 : * This is a table of -log(value/255)/log(2) for 'value' in the range 128 to
3518 : * 255, so it's the base 2 logarithm of a normalized 8-bit floating point
3519 : * mantissa. The numbers are 32-bit fractions.
3520 : */
3521 : static const png_uint_32
3522 : png_8bit_l2[128] =
3523 : {
3524 : 4270715492U, 4222494797U, 4174646467U, 4127164793U, 4080044201U, 4033279239U,
3525 : 3986864580U, 3940795015U, 3895065449U, 3849670902U, 3804606499U, 3759867474U,
3526 : 3715449162U, 3671346997U, 3627556511U, 3584073329U, 3540893168U, 3498011834U,
3527 : 3455425220U, 3413129301U, 3371120137U, 3329393864U, 3287946700U, 3246774933U,
3528 : 3205874930U, 3165243125U, 3124876025U, 3084770202U, 3044922296U, 3005329011U,
3529 : 2965987113U, 2926893432U, 2888044853U, 2849438323U, 2811070844U, 2772939474U,
3530 : 2735041326U, 2697373562U, 2659933400U, 2622718104U, 2585724991U, 2548951424U,
3531 : 2512394810U, 2476052606U, 2439922311U, 2404001468U, 2368287663U, 2332778523U,
3532 : 2297471715U, 2262364947U, 2227455964U, 2192742551U, 2158222529U, 2123893754U,
3533 : 2089754119U, 2055801552U, 2022034013U, 1988449497U, 1955046031U, 1921821672U,
3534 : 1888774511U, 1855902668U, 1823204291U, 1790677560U, 1758320682U, 1726131893U,
3535 : 1694109454U, 1662251657U, 1630556815U, 1599023271U, 1567649391U, 1536433567U,
3536 : 1505374214U, 1474469770U, 1443718700U, 1413119487U, 1382670639U, 1352370686U,
3537 : 1322218179U, 1292211689U, 1262349810U, 1232631153U, 1203054352U, 1173618059U,
3538 : 1144320946U, 1115161701U, 1086139034U, 1057251672U, 1028498358U, 999877854U,
3539 : 971388940U, 943030410U, 914801076U, 886699767U, 858725327U, 830876614U,
3540 : 803152505U, 775551890U, 748073672U, 720716771U, 693480120U, 666362667U,
3541 : 639363374U, 612481215U, 585715177U, 559064263U, 532527486U, 506103872U,
3542 : 479792461U, 453592303U, 427502463U, 401522014U, 375650043U, 349885648U,
3543 : 324227938U, 298676034U, 273229066U, 247886176U, 222646516U, 197509248U,
3544 : 172473545U, 147538590U, 122703574U, 97967701U, 73330182U, 48790236U,
3545 : 24347096U, 0U
3546 :
3547 : #if 0
3548 : /* The following are the values for 16-bit tables - these work fine for the
3549 : * 8-bit conversions but produce very slightly larger errors in the 16-bit
3550 : * log (about 1.2 as opposed to 0.7 absolute error in the final value). To
3551 : * use these all the shifts below must be adjusted appropriately.
3552 : */
3553 : 65166, 64430, 63700, 62976, 62257, 61543, 60835, 60132, 59434, 58741, 58054,
3554 : 57371, 56693, 56020, 55352, 54689, 54030, 53375, 52726, 52080, 51439, 50803,
3555 : 50170, 49542, 48918, 48298, 47682, 47070, 46462, 45858, 45257, 44661, 44068,
3556 : 43479, 42894, 42312, 41733, 41159, 40587, 40020, 39455, 38894, 38336, 37782,
3557 : 37230, 36682, 36137, 35595, 35057, 34521, 33988, 33459, 32932, 32408, 31887,
3558 : 31369, 30854, 30341, 29832, 29325, 28820, 28319, 27820, 27324, 26830, 26339,
3559 : 25850, 25364, 24880, 24399, 23920, 23444, 22970, 22499, 22029, 21562, 21098,
3560 : 20636, 20175, 19718, 19262, 18808, 18357, 17908, 17461, 17016, 16573, 16132,
3561 : 15694, 15257, 14822, 14390, 13959, 13530, 13103, 12678, 12255, 11834, 11415,
3562 : 10997, 10582, 10168, 9756, 9346, 8937, 8531, 8126, 7723, 7321, 6921, 6523,
3563 : 6127, 5732, 5339, 4947, 4557, 4169, 3782, 3397, 3014, 2632, 2251, 1872, 1495,
3564 : 1119, 744, 372
3565 : #endif
3566 : };
3567 :
3568 : static png_int_32
3569 : png_log8bit(unsigned int x)
3570 : {
3571 : unsigned int lg2 = 0;
3572 : /* Each time 'x' is multiplied by 2, 1 must be subtracted off the final log,
3573 : * because the log is actually negate that means adding 1. The final
3574 : * returned value thus has the range 0 (for 255 input) to 7.994 (for 1
3575 : * input), return -1 for the overflow (log 0) case, - so the result is
3576 : * always at most 19 bits.
3577 : */
3578 : if ((x &= 0xff) == 0)
3579 : return -1;
3580 :
3581 : if ((x & 0xf0) == 0)
3582 : lg2 = 4, x <<= 4;
3583 :
3584 : if ((x & 0xc0) == 0)
3585 : lg2 += 2, x <<= 2;
3586 :
3587 : if ((x & 0x80) == 0)
3588 : lg2 += 1, x <<= 1;
3589 :
3590 : /* result is at most 19 bits, so this cast is safe: */
3591 : return (png_int_32)((lg2 << 16) + ((png_8bit_l2[x-128]+32768)>>16));
3592 : }
3593 :
3594 : /* The above gives exact (to 16 binary places) log2 values for 8-bit images,
3595 : * for 16-bit images we use the most significant 8 bits of the 16-bit value to
3596 : * get an approximation then multiply the approximation by a correction factor
3597 : * determined by the remaining up to 8 bits. This requires an additional step
3598 : * in the 16-bit case.
3599 : *
3600 : * We want log2(value/65535), we have log2(v'/255), where:
3601 : *
3602 : * value = v' * 256 + v''
3603 : * = v' * f
3604 : *
3605 : * So f is value/v', which is equal to (256+v''/v') since v' is in the range 128
3606 : * to 255 and v'' is in the range 0 to 255 f will be in the range 256 to less
3607 : * than 258. The final factor also needs to correct for the fact that our 8-bit
3608 : * value is scaled by 255, whereas the 16-bit values must be scaled by 65535.
3609 : *
3610 : * This gives a final formula using a calculated value 'x' which is value/v' and
3611 : * scaling by 65536 to match the above table:
3612 : *
3613 : * log2(x/257) * 65536
3614 : *
3615 : * Since these numbers are so close to '1' we can use simple linear
3616 : * interpolation between the two end values 256/257 (result -368.61) and 258/257
3617 : * (result 367.179). The values used below are scaled by a further 64 to give
3618 : * 16-bit precision in the interpolation:
3619 : *
3620 : * Start (256): -23591
3621 : * Zero (257): 0
3622 : * End (258): 23499
3623 : */
3624 : #ifdef PNG_16BIT_SUPPORTED
3625 : static png_int_32
3626 : png_log16bit(png_uint_32 x)
3627 : {
3628 : unsigned int lg2 = 0;
3629 :
3630 : /* As above, but now the input has 16 bits. */
3631 : if ((x &= 0xffff) == 0)
3632 : return -1;
3633 :
3634 : if ((x & 0xff00) == 0)
3635 : lg2 = 8, x <<= 8;
3636 :
3637 : if ((x & 0xf000) == 0)
3638 : lg2 += 4, x <<= 4;
3639 :
3640 : if ((x & 0xc000) == 0)
3641 : lg2 += 2, x <<= 2;
3642 :
3643 : if ((x & 0x8000) == 0)
3644 : lg2 += 1, x <<= 1;
3645 :
3646 : /* Calculate the base logarithm from the top 8 bits as a 28-bit fractional
3647 : * value.
3648 : */
3649 : lg2 <<= 28;
3650 : lg2 += (png_8bit_l2[(x>>8)-128]+8) >> 4;
3651 :
3652 : /* Now we need to interpolate the factor, this requires a division by the top
3653 : * 8 bits. Do this with maximum precision.
3654 : */
3655 : x = ((x << 16) + (x >> 9)) / (x >> 8);
3656 :
3657 : /* Since we divided by the top 8 bits of 'x' there will be a '1' at 1<<24,
3658 : * the value at 1<<16 (ignoring this) will be 0 or 1; this gives us exactly
3659 : * 16 bits to interpolate to get the low bits of the result. Round the
3660 : * answer. Note that the end point values are scaled by 64 to retain overall
3661 : * precision and that 'lg2' is current scaled by an extra 12 bits, so adjust
3662 : * the overall scaling by 6-12. Round at every step.
3663 : */
3664 : x -= 1U << 24;
3665 :
3666 : if (x <= 65536U) /* <= '257' */
3667 : lg2 += ((23591U * (65536U-x)) + (1U << (16+6-12-1))) >> (16+6-12);
3668 :
3669 : else
3670 : lg2 -= ((23499U * (x-65536U)) + (1U << (16+6-12-1))) >> (16+6-12);
3671 :
3672 : /* Safe, because the result can't have more than 20 bits: */
3673 : return (png_int_32)((lg2 + 2048) >> 12);
3674 : }
3675 : #endif /* 16BIT */
3676 :
3677 : /* The 'exp()' case must invert the above, taking a 20-bit fixed point
3678 : * logarithmic value and returning a 16 or 8-bit number as appropriate. In
3679 : * each case only the low 16 bits are relevant - the fraction - since the
3680 : * integer bits (the top 4) simply determine a shift.
3681 : *
3682 : * The worst case is the 16-bit distinction between 65535 and 65534. This
3683 : * requires perhaps spurious accuracy in the decoding of the logarithm to
3684 : * distinguish log2(65535/65534.5) - 10^-5 or 17 bits. There is little chance
3685 : * of getting this accuracy in practice.
3686 : *
3687 : * To deal with this the following exp() function works out the exponent of the
3688 : * frational part of the logarithm by using an accurate 32-bit value from the
3689 : * top four fractional bits then multiplying in the remaining bits.
3690 : */
3691 : static const png_uint_32
3692 : png_32bit_exp[16] =
3693 : {
3694 : /* NOTE: the first entry is deliberately set to the maximum 32-bit value. */
3695 : 4294967295U, 4112874773U, 3938502376U, 3771522796U, 3611622603U, 3458501653U,
3696 : 3311872529U, 3171459999U, 3037000500U, 2908241642U, 2784941738U, 2666869345U,
3697 : 2553802834U, 2445529972U, 2341847524U, 2242560872U
3698 : };
3699 :
3700 : /* Adjustment table; provided to explain the numbers in the code below. */
3701 : #if 0
3702 : for (i=11;i>=0;--i){ print i, " ", (1 - e(-(2^i)/65536*l(2))) * 2^(32-i), "\n"}
3703 : 11 44937.64284865548751208448
3704 : 10 45180.98734845585101160448
3705 : 9 45303.31936980687359311872
3706 : 8 45364.65110595323018870784
3707 : 7 45395.35850361789624614912
3708 : 6 45410.72259715102037508096
3709 : 5 45418.40724413220722311168
3710 : 4 45422.25021786898173001728
3711 : 3 45424.17186732298419044352
3712 : 2 45425.13273269940811464704
3713 : 1 45425.61317555035558641664
3714 : 0 45425.85339951654943850496
3715 : #endif
3716 :
3717 : static png_uint_32
3718 : png_exp(png_fixed_point x)
3719 : {
3720 : if (x > 0 && x <= 0xfffff) /* Else overflow or zero (underflow) */
3721 : {
3722 : /* Obtain a 4-bit approximation */
3723 : png_uint_32 e = png_32bit_exp[(x >> 12) & 0x0f];
3724 :
3725 : /* Incorporate the low 12 bits - these decrease the returned value by
3726 : * multiplying by a number less than 1 if the bit is set. The multiplier
3727 : * is determined by the above table and the shift. Notice that the values
3728 : * converge on 45426 and this is used to allow linear interpolation of the
3729 : * low bits.
3730 : */
3731 : if (x & 0x800)
3732 : e -= (((e >> 16) * 44938U) + 16U) >> 5;
3733 :
3734 : if (x & 0x400)
3735 : e -= (((e >> 16) * 45181U) + 32U) >> 6;
3736 :
3737 : if (x & 0x200)
3738 : e -= (((e >> 16) * 45303U) + 64U) >> 7;
3739 :
3740 : if (x & 0x100)
3741 : e -= (((e >> 16) * 45365U) + 128U) >> 8;
3742 :
3743 : if (x & 0x080)
3744 : e -= (((e >> 16) * 45395U) + 256U) >> 9;
3745 :
3746 : if (x & 0x040)
3747 : e -= (((e >> 16) * 45410U) + 512U) >> 10;
3748 :
3749 : /* And handle the low 6 bits in a single block. */
3750 : e -= (((e >> 16) * 355U * (x & 0x3fU)) + 256U) >> 9;
3751 :
3752 : /* Handle the upper bits of x. */
3753 : e >>= x >> 16;
3754 : return e;
3755 : }
3756 :
3757 : /* Check for overflow */
3758 : if (x <= 0)
3759 : return png_32bit_exp[0];
3760 :
3761 : /* Else underflow */
3762 : return 0;
3763 : }
3764 :
3765 : static png_byte
3766 : png_exp8bit(png_fixed_point lg2)
3767 : {
3768 : /* Get a 32-bit value: */
3769 : png_uint_32 x = png_exp(lg2);
3770 :
3771 : /* Convert the 32-bit value to 0..255 by multiplying by 256-1. Note that the
3772 : * second, rounding, step can't overflow because of the first, subtraction,
3773 : * step.
3774 : */
3775 : x -= x >> 8;
3776 : return (png_byte)(((x + 0x7fffffU) >> 24) & 0xff);
3777 : }
3778 :
3779 : #ifdef PNG_16BIT_SUPPORTED
3780 : static png_uint_16
3781 : png_exp16bit(png_fixed_point lg2)
3782 : {
3783 : /* Get a 32-bit value: */
3784 : png_uint_32 x = png_exp(lg2);
3785 :
3786 : /* Convert the 32-bit value to 0..65535 by multiplying by 65536-1: */
3787 : x -= x >> 16;
3788 : return (png_uint_16)((x + 32767U) >> 16);
3789 : }
3790 : #endif /* 16BIT */
3791 : #endif /* FLOATING_ARITHMETIC */
3792 :
3793 : png_byte
3794 0 : png_gamma_8bit_correct(unsigned int value, png_fixed_point gamma_val)
3795 : {
3796 0 : if (value > 0 && value < 255)
3797 : {
3798 : # ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
3799 : /* 'value' is unsigned, ANSI-C90 requires the compiler to correctly
3800 : * convert this to a floating point value. This includes values that
3801 : * would overflow if 'value' were to be converted to 'int'.
3802 : *
3803 : * Apparently GCC, however, does an intermediate conversion to (int)
3804 : * on some (ARM) but not all (x86) platforms, possibly because of
3805 : * hardware FP limitations. (E.g. if the hardware conversion always
3806 : * assumes the integer register contains a signed value.) This results
3807 : * in ANSI-C undefined behavior for large values.
3808 : *
3809 : * Other implementations on the same machine might actually be ANSI-C90
3810 : * conformant and therefore compile spurious extra code for the large
3811 : * values.
3812 : *
3813 : * We can be reasonably sure that an unsigned to float conversion
3814 : * won't be faster than an int to float one. Therefore this code
3815 : * assumes responsibility for the undefined behavior, which it knows
3816 : * can't happen because of the check above.
3817 : *
3818 : * Note the argument to this routine is an (unsigned int) because, on
3819 : * 16-bit platforms, it is assigned a value which might be out of
3820 : * range for an (int); that would result in undefined behavior in the
3821 : * caller if the *argument* ('value') were to be declared (int).
3822 : */
3823 0 : double r = floor(255*pow((int)/*SAFE*/value/255.,gamma_val*.00001)+.5);
3824 0 : return (png_byte)r;
3825 : # else
3826 : png_int_32 lg2 = png_log8bit(value);
3827 : png_fixed_point res;
3828 :
3829 : if (png_muldiv(&res, gamma_val, lg2, PNG_FP_1) != 0)
3830 : return png_exp8bit(res);
3831 :
3832 : /* Overflow. */
3833 : value = 0;
3834 : # endif
3835 : }
3836 :
3837 0 : return (png_byte)(value & 0xff);
3838 : }
3839 :
3840 : #ifdef PNG_16BIT_SUPPORTED
3841 : png_uint_16
3842 0 : png_gamma_16bit_correct(unsigned int value, png_fixed_point gamma_val)
3843 : {
3844 0 : if (value > 0 && value < 65535)
3845 : {
3846 : # ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
3847 : /* The same (unsigned int)->(double) constraints apply here as above,
3848 : * however in this case the (unsigned int) to (int) conversion can
3849 : * overflow on an ANSI-C90 compliant system so the cast needs to ensure
3850 : * that this is not possible.
3851 : */
3852 0 : double r = floor(65535*pow((png_int_32)value/65535.,
3853 : gamma_val*.00001)+.5);
3854 0 : return (png_uint_16)r;
3855 : # else
3856 : png_int_32 lg2 = png_log16bit(value);
3857 : png_fixed_point res;
3858 :
3859 : if (png_muldiv(&res, gamma_val, lg2, PNG_FP_1) != 0)
3860 : return png_exp16bit(res);
3861 :
3862 : /* Overflow. */
3863 : value = 0;
3864 : # endif
3865 : }
3866 :
3867 0 : return (png_uint_16)value;
3868 : }
3869 : #endif /* 16BIT */
3870 :
3871 : /* This does the right thing based on the bit_depth field of the
3872 : * png_struct, interpreting values as 8-bit or 16-bit. While the result
3873 : * is nominally a 16-bit value if bit depth is 8 then the result is
3874 : * 8-bit (as are the arguments.)
3875 : */
3876 : png_uint_16 /* PRIVATE */
3877 0 : png_gamma_correct(png_structrp png_ptr, unsigned int value,
3878 : png_fixed_point gamma_val)
3879 : {
3880 0 : if (png_ptr->bit_depth == 8)
3881 0 : return png_gamma_8bit_correct(value, gamma_val);
3882 :
3883 : #ifdef PNG_16BIT_SUPPORTED
3884 : else
3885 0 : return png_gamma_16bit_correct(value, gamma_val);
3886 : #else
3887 : /* should not reach this */
3888 : return 0;
3889 : #endif /* 16BIT */
3890 : }
3891 :
3892 : #ifdef PNG_16BIT_SUPPORTED
3893 : /* Internal function to build a single 16-bit table - the table consists of
3894 : * 'num' 256 entry subtables, where 'num' is determined by 'shift' - the amount
3895 : * to shift the input values right (or 16-number_of_signifiant_bits).
3896 : *
3897 : * The caller is responsible for ensuring that the table gets cleaned up on
3898 : * png_error (i.e. if one of the mallocs below fails) - i.e. the *table argument
3899 : * should be somewhere that will be cleaned.
3900 : */
3901 : static void
3902 0 : png_build_16bit_table(png_structrp png_ptr, png_uint_16pp *ptable,
3903 : PNG_CONST unsigned int shift, PNG_CONST png_fixed_point gamma_val)
3904 : {
3905 : /* Various values derived from 'shift': */
3906 0 : PNG_CONST unsigned int num = 1U << (8U - shift);
3907 : #ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
3908 : /* CSE the division and work round wacky GCC warnings (see the comments
3909 : * in png_gamma_8bit_correct for where these come from.)
3910 : */
3911 0 : PNG_CONST double fmax = 1./(((png_int_32)1 << (16U - shift))-1);
3912 : #endif
3913 0 : PNG_CONST unsigned int max = (1U << (16U - shift))-1U;
3914 0 : PNG_CONST unsigned int max_by_2 = 1U << (15U-shift);
3915 : unsigned int i;
3916 :
3917 0 : png_uint_16pp table = *ptable =
3918 0 : (png_uint_16pp)png_calloc(png_ptr, num * (sizeof (png_uint_16p)));
3919 :
3920 0 : for (i = 0; i < num; i++)
3921 : {
3922 0 : png_uint_16p sub_table = table[i] =
3923 0 : (png_uint_16p)png_malloc(png_ptr, 256 * (sizeof (png_uint_16)));
3924 :
3925 : /* The 'threshold' test is repeated here because it can arise for one of
3926 : * the 16-bit tables even if the others don't hit it.
3927 : */
3928 0 : if (png_gamma_significant(gamma_val) != 0)
3929 : {
3930 : /* The old code would overflow at the end and this would cause the
3931 : * 'pow' function to return a result >1, resulting in an
3932 : * arithmetic error. This code follows the spec exactly; ig is
3933 : * the recovered input sample, it always has 8-16 bits.
3934 : *
3935 : * We want input * 65535/max, rounded, the arithmetic fits in 32
3936 : * bits (unsigned) so long as max <= 32767.
3937 : */
3938 : unsigned int j;
3939 0 : for (j = 0; j < 256; j++)
3940 : {
3941 0 : png_uint_32 ig = (j << (8-shift)) + i;
3942 : # ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
3943 : /* Inline the 'max' scaling operation: */
3944 : /* See png_gamma_8bit_correct for why the cast to (int) is
3945 : * required here.
3946 : */
3947 0 : double d = floor(65535.*pow(ig*fmax, gamma_val*.00001)+.5);
3948 0 : sub_table[j] = (png_uint_16)d;
3949 : # else
3950 : if (shift != 0)
3951 : ig = (ig * 65535U + max_by_2)/max;
3952 :
3953 : sub_table[j] = png_gamma_16bit_correct(ig, gamma_val);
3954 : # endif
3955 : }
3956 : }
3957 : else
3958 : {
3959 : /* We must still build a table, but do it the fast way. */
3960 : unsigned int j;
3961 :
3962 0 : for (j = 0; j < 256; j++)
3963 : {
3964 0 : png_uint_32 ig = (j << (8-shift)) + i;
3965 :
3966 0 : if (shift != 0)
3967 0 : ig = (ig * 65535U + max_by_2)/max;
3968 :
3969 0 : sub_table[j] = (png_uint_16)ig;
3970 : }
3971 : }
3972 : }
3973 0 : }
3974 :
3975 : /* NOTE: this function expects the *inverse* of the overall gamma transformation
3976 : * required.
3977 : */
3978 : static void
3979 0 : png_build_16to8_table(png_structrp png_ptr, png_uint_16pp *ptable,
3980 : PNG_CONST unsigned int shift, PNG_CONST png_fixed_point gamma_val)
3981 : {
3982 0 : PNG_CONST unsigned int num = 1U << (8U - shift);
3983 0 : PNG_CONST unsigned int max = (1U << (16U - shift))-1U;
3984 : unsigned int i;
3985 : png_uint_32 last;
3986 :
3987 0 : png_uint_16pp table = *ptable =
3988 0 : (png_uint_16pp)png_calloc(png_ptr, num * (sizeof (png_uint_16p)));
3989 :
3990 : /* 'num' is the number of tables and also the number of low bits of low
3991 : * bits of the input 16-bit value used to select a table. Each table is
3992 : * itself indexed by the high 8 bits of the value.
3993 : */
3994 0 : for (i = 0; i < num; i++)
3995 0 : table[i] = (png_uint_16p)png_malloc(png_ptr,
3996 : 256 * (sizeof (png_uint_16)));
3997 :
3998 : /* 'gamma_val' is set to the reciprocal of the value calculated above, so
3999 : * pow(out,g) is an *input* value. 'last' is the last input value set.
4000 : *
4001 : * In the loop 'i' is used to find output values. Since the output is
4002 : * 8-bit there are only 256 possible values. The tables are set up to
4003 : * select the closest possible output value for each input by finding
4004 : * the input value at the boundary between each pair of output values
4005 : * and filling the table up to that boundary with the lower output
4006 : * value.
4007 : *
4008 : * The boundary values are 0.5,1.5..253.5,254.5. Since these are 9-bit
4009 : * values the code below uses a 16-bit value in i; the values start at
4010 : * 128.5 (for 0.5) and step by 257, for a total of 254 values (the last
4011 : * entries are filled with 255). Start i at 128 and fill all 'last'
4012 : * table entries <= 'max'
4013 : */
4014 0 : last = 0;
4015 0 : for (i = 0; i < 255; ++i) /* 8-bit output value */
4016 : {
4017 : /* Find the corresponding maximum input value */
4018 0 : png_uint_16 out = (png_uint_16)(i * 257U); /* 16-bit output value */
4019 :
4020 : /* Find the boundary value in 16 bits: */
4021 0 : png_uint_32 bound = png_gamma_16bit_correct(out+128U, gamma_val);
4022 :
4023 : /* Adjust (round) to (16-shift) bits: */
4024 0 : bound = (bound * max + 32768U)/65535U + 1U;
4025 :
4026 0 : while (last < bound)
4027 : {
4028 0 : table[last & (0xffU >> shift)][last >> (8U - shift)] = out;
4029 0 : last++;
4030 : }
4031 : }
4032 :
4033 : /* And fill in the final entries. */
4034 0 : while (last < (num << 8))
4035 : {
4036 0 : table[last & (0xff >> shift)][last >> (8U - shift)] = 65535U;
4037 0 : last++;
4038 : }
4039 0 : }
4040 : #endif /* 16BIT */
4041 :
4042 : /* Build a single 8-bit table: same as the 16-bit case but much simpler (and
4043 : * typically much faster). Note that libpng currently does no sBIT processing
4044 : * (apparently contrary to the spec) so a 256-entry table is always generated.
4045 : */
4046 : static void
4047 0 : png_build_8bit_table(png_structrp png_ptr, png_bytepp ptable,
4048 : PNG_CONST png_fixed_point gamma_val)
4049 : {
4050 : unsigned int i;
4051 0 : png_bytep table = *ptable = (png_bytep)png_malloc(png_ptr, 256);
4052 :
4053 0 : if (png_gamma_significant(gamma_val) != 0)
4054 0 : for (i=0; i<256; i++)
4055 0 : table[i] = png_gamma_8bit_correct(i, gamma_val);
4056 :
4057 : else
4058 0 : for (i=0; i<256; ++i)
4059 0 : table[i] = (png_byte)(i & 0xff);
4060 0 : }
4061 :
4062 : /* Used from png_read_destroy and below to release the memory used by the gamma
4063 : * tables.
4064 : */
4065 : void /* PRIVATE */
4066 31 : png_destroy_gamma_table(png_structrp png_ptr)
4067 : {
4068 31 : png_free(png_ptr, png_ptr->gamma_table);
4069 31 : png_ptr->gamma_table = NULL;
4070 :
4071 : #ifdef PNG_16BIT_SUPPORTED
4072 31 : if (png_ptr->gamma_16_table != NULL)
4073 : {
4074 : int i;
4075 0 : int istop = (1 << (8 - png_ptr->gamma_shift));
4076 0 : for (i = 0; i < istop; i++)
4077 : {
4078 0 : png_free(png_ptr, png_ptr->gamma_16_table[i]);
4079 : }
4080 0 : png_free(png_ptr, png_ptr->gamma_16_table);
4081 0 : png_ptr->gamma_16_table = NULL;
4082 : }
4083 : #endif /* 16BIT */
4084 :
4085 : #if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
4086 : defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
4087 : defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
4088 : png_free(png_ptr, png_ptr->gamma_from_1);
4089 : png_ptr->gamma_from_1 = NULL;
4090 : png_free(png_ptr, png_ptr->gamma_to_1);
4091 : png_ptr->gamma_to_1 = NULL;
4092 :
4093 : #ifdef PNG_16BIT_SUPPORTED
4094 : if (png_ptr->gamma_16_from_1 != NULL)
4095 : {
4096 : int i;
4097 : int istop = (1 << (8 - png_ptr->gamma_shift));
4098 : for (i = 0; i < istop; i++)
4099 : {
4100 : png_free(png_ptr, png_ptr->gamma_16_from_1[i]);
4101 : }
4102 : png_free(png_ptr, png_ptr->gamma_16_from_1);
4103 : png_ptr->gamma_16_from_1 = NULL;
4104 : }
4105 : if (png_ptr->gamma_16_to_1 != NULL)
4106 : {
4107 : int i;
4108 : int istop = (1 << (8 - png_ptr->gamma_shift));
4109 : for (i = 0; i < istop; i++)
4110 : {
4111 : png_free(png_ptr, png_ptr->gamma_16_to_1[i]);
4112 : }
4113 : png_free(png_ptr, png_ptr->gamma_16_to_1);
4114 : png_ptr->gamma_16_to_1 = NULL;
4115 : }
4116 : #endif /* 16BIT */
4117 : #endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
4118 31 : }
4119 :
4120 : /* We build the 8- or 16-bit gamma tables here. Note that for 16-bit
4121 : * tables, we don't make a full table if we are reducing to 8-bit in
4122 : * the future. Note also how the gamma_16 tables are segmented so that
4123 : * we don't need to allocate > 64K chunks for a full 16-bit table.
4124 : */
4125 : void /* PRIVATE */
4126 0 : png_build_gamma_table(png_structrp png_ptr, int bit_depth)
4127 : {
4128 : png_debug(1, "in png_build_gamma_table");
4129 :
4130 : /* Remove any existing table; this copes with multiple calls to
4131 : * png_read_update_info. The warning is because building the gamma tables
4132 : * multiple times is a performance hit - it's harmless but the ability to
4133 : * call png_read_update_info() multiple times is new in 1.5.6 so it seems
4134 : * sensible to warn if the app introduces such a hit.
4135 : */
4136 0 : if (png_ptr->gamma_table != NULL || png_ptr->gamma_16_table != NULL)
4137 : {
4138 0 : png_warning(png_ptr, "gamma table being rebuilt");
4139 0 : png_destroy_gamma_table(png_ptr);
4140 : }
4141 :
4142 0 : if (bit_depth <= 8)
4143 : {
4144 0 : png_build_8bit_table(png_ptr, &png_ptr->gamma_table,
4145 0 : png_ptr->screen_gamma > 0 ?
4146 0 : png_reciprocal2(png_ptr->colorspace.gamma,
4147 : png_ptr->screen_gamma) : PNG_FP_1);
4148 :
4149 : #if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
4150 : defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
4151 : defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
4152 : if ((png_ptr->transformations & (PNG_COMPOSE | PNG_RGB_TO_GRAY)) != 0)
4153 : {
4154 : png_build_8bit_table(png_ptr, &png_ptr->gamma_to_1,
4155 : png_reciprocal(png_ptr->colorspace.gamma));
4156 :
4157 : png_build_8bit_table(png_ptr, &png_ptr->gamma_from_1,
4158 : png_ptr->screen_gamma > 0 ?
4159 : png_reciprocal(png_ptr->screen_gamma) :
4160 : png_ptr->colorspace.gamma/* Probably doing rgb_to_gray */);
4161 : }
4162 : #endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
4163 : }
4164 : #ifdef PNG_16BIT_SUPPORTED
4165 : else
4166 : {
4167 : png_byte shift, sig_bit;
4168 :
4169 0 : if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
4170 : {
4171 0 : sig_bit = png_ptr->sig_bit.red;
4172 :
4173 0 : if (png_ptr->sig_bit.green > sig_bit)
4174 0 : sig_bit = png_ptr->sig_bit.green;
4175 :
4176 0 : if (png_ptr->sig_bit.blue > sig_bit)
4177 0 : sig_bit = png_ptr->sig_bit.blue;
4178 : }
4179 : else
4180 0 : sig_bit = png_ptr->sig_bit.gray;
4181 :
4182 : /* 16-bit gamma code uses this equation:
4183 : *
4184 : * ov = table[(iv & 0xff) >> gamma_shift][iv >> 8]
4185 : *
4186 : * Where 'iv' is the input color value and 'ov' is the output value -
4187 : * pow(iv, gamma).
4188 : *
4189 : * Thus the gamma table consists of up to 256 256-entry tables. The table
4190 : * is selected by the (8-gamma_shift) most significant of the low 8 bits
4191 : * of the color value then indexed by the upper 8 bits:
4192 : *
4193 : * table[low bits][high 8 bits]
4194 : *
4195 : * So the table 'n' corresponds to all those 'iv' of:
4196 : *
4197 : * <all high 8-bit values><n << gamma_shift>..<(n+1 << gamma_shift)-1>
4198 : *
4199 : */
4200 0 : if (sig_bit > 0 && sig_bit < 16U)
4201 : /* shift == insignificant bits */
4202 0 : shift = (png_byte)((16U - sig_bit) & 0xff);
4203 :
4204 : else
4205 0 : shift = 0; /* keep all 16 bits */
4206 :
4207 0 : if ((png_ptr->transformations & (PNG_16_TO_8 | PNG_SCALE_16_TO_8)) != 0)
4208 : {
4209 : /* PNG_MAX_GAMMA_8 is the number of bits to keep - effectively
4210 : * the significant bits in the *input* when the output will
4211 : * eventually be 8 bits. By default it is 11.
4212 : */
4213 0 : if (shift < (16U - PNG_MAX_GAMMA_8))
4214 0 : shift = (16U - PNG_MAX_GAMMA_8);
4215 : }
4216 :
4217 0 : if (shift > 8U)
4218 0 : shift = 8U; /* Guarantees at least one table! */
4219 :
4220 0 : png_ptr->gamma_shift = shift;
4221 :
4222 : /* NOTE: prior to 1.5.4 this test used to include PNG_BACKGROUND (now
4223 : * PNG_COMPOSE). This effectively smashed the background calculation for
4224 : * 16-bit output because the 8-bit table assumes the result will be
4225 : * reduced to 8 bits.
4226 : */
4227 0 : if ((png_ptr->transformations & (PNG_16_TO_8 | PNG_SCALE_16_TO_8)) != 0)
4228 0 : png_build_16to8_table(png_ptr, &png_ptr->gamma_16_table, shift,
4229 0 : png_ptr->screen_gamma > 0 ? png_product2(png_ptr->colorspace.gamma,
4230 : png_ptr->screen_gamma) : PNG_FP_1);
4231 :
4232 : else
4233 0 : png_build_16bit_table(png_ptr, &png_ptr->gamma_16_table, shift,
4234 0 : png_ptr->screen_gamma > 0 ? png_reciprocal2(png_ptr->colorspace.gamma,
4235 : png_ptr->screen_gamma) : PNG_FP_1);
4236 :
4237 : #if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
4238 : defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
4239 : defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
4240 : if ((png_ptr->transformations & (PNG_COMPOSE | PNG_RGB_TO_GRAY)) != 0)
4241 : {
4242 : png_build_16bit_table(png_ptr, &png_ptr->gamma_16_to_1, shift,
4243 : png_reciprocal(png_ptr->colorspace.gamma));
4244 :
4245 : /* Notice that the '16 from 1' table should be full precision, however
4246 : * the lookup on this table still uses gamma_shift, so it can't be.
4247 : * TODO: fix this.
4248 : */
4249 : png_build_16bit_table(png_ptr, &png_ptr->gamma_16_from_1, shift,
4250 : png_ptr->screen_gamma > 0 ? png_reciprocal(png_ptr->screen_gamma) :
4251 : png_ptr->colorspace.gamma/* Probably doing rgb_to_gray */);
4252 : }
4253 : #endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
4254 : }
4255 : #endif /* 16BIT */
4256 0 : }
4257 : #endif /* READ_GAMMA */
4258 :
4259 : /* HARDWARE OR SOFTWARE OPTION SUPPORT */
4260 : #ifdef PNG_SET_OPTION_SUPPORTED
4261 : int PNGAPI
4262 31 : png_set_option(png_structrp png_ptr, int option, int onoff)
4263 : {
4264 62 : if (png_ptr != NULL && option >= 0 && option < PNG_OPTION_NEXT &&
4265 31 : (option & 1) == 0)
4266 : {
4267 31 : png_uint_32 mask = 3U << option;
4268 31 : png_uint_32 setting = (2U + (onoff != 0)) << option;
4269 31 : png_uint_32 current = png_ptr->options;
4270 :
4271 31 : png_ptr->options = (png_uint_32)(((current & ~mask) | setting) & 0xff);
4272 :
4273 31 : return (int)(current & mask) >> option;
4274 : }
4275 :
4276 0 : return PNG_OPTION_INVALID;
4277 : }
4278 : #endif
4279 :
4280 : /* sRGB support */
4281 : #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
4282 : defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
4283 : /* sRGB conversion tables; these are machine generated with the code in
4284 : * contrib/tools/makesRGB.c. The actual sRGB transfer curve defined in the
4285 : * specification (see the article at http://en.wikipedia.org/wiki/SRGB)
4286 : * is used, not the gamma=1/2.2 approximation use elsewhere in libpng.
4287 : * The sRGB to linear table is exact (to the nearest 16-bit linear fraction).
4288 : * The inverse (linear to sRGB) table has accuracies as follows:
4289 : *
4290 : * For all possible (255*65535+1) input values:
4291 : *
4292 : * error: -0.515566 - 0.625971, 79441 (0.475369%) of readings inexact
4293 : *
4294 : * For the input values corresponding to the 65536 16-bit values:
4295 : *
4296 : * error: -0.513727 - 0.607759, 308 (0.469978%) of readings inexact
4297 : *
4298 : * In all cases the inexact readings are only off by one.
4299 : */
4300 :
4301 : #ifdef PNG_SIMPLIFIED_READ_SUPPORTED
4302 : /* The convert-to-sRGB table is only currently required for read. */
4303 : const png_uint_16 png_sRGB_table[256] =
4304 : {
4305 : 0,20,40,60,80,99,119,139,
4306 : 159,179,199,219,241,264,288,313,
4307 : 340,367,396,427,458,491,526,562,
4308 : 599,637,677,718,761,805,851,898,
4309 : 947,997,1048,1101,1156,1212,1270,1330,
4310 : 1391,1453,1517,1583,1651,1720,1790,1863,
4311 : 1937,2013,2090,2170,2250,2333,2418,2504,
4312 : 2592,2681,2773,2866,2961,3058,3157,3258,
4313 : 3360,3464,3570,3678,3788,3900,4014,4129,
4314 : 4247,4366,4488,4611,4736,4864,4993,5124,
4315 : 5257,5392,5530,5669,5810,5953,6099,6246,
4316 : 6395,6547,6700,6856,7014,7174,7335,7500,
4317 : 7666,7834,8004,8177,8352,8528,8708,8889,
4318 : 9072,9258,9445,9635,9828,10022,10219,10417,
4319 : 10619,10822,11028,11235,11446,11658,11873,12090,
4320 : 12309,12530,12754,12980,13209,13440,13673,13909,
4321 : 14146,14387,14629,14874,15122,15371,15623,15878,
4322 : 16135,16394,16656,16920,17187,17456,17727,18001,
4323 : 18277,18556,18837,19121,19407,19696,19987,20281,
4324 : 20577,20876,21177,21481,21787,22096,22407,22721,
4325 : 23038,23357,23678,24002,24329,24658,24990,25325,
4326 : 25662,26001,26344,26688,27036,27386,27739,28094,
4327 : 28452,28813,29176,29542,29911,30282,30656,31033,
4328 : 31412,31794,32179,32567,32957,33350,33745,34143,
4329 : 34544,34948,35355,35764,36176,36591,37008,37429,
4330 : 37852,38278,38706,39138,39572,40009,40449,40891,
4331 : 41337,41785,42236,42690,43147,43606,44069,44534,
4332 : 45002,45473,45947,46423,46903,47385,47871,48359,
4333 : 48850,49344,49841,50341,50844,51349,51858,52369,
4334 : 52884,53401,53921,54445,54971,55500,56032,56567,
4335 : 57105,57646,58190,58737,59287,59840,60396,60955,
4336 : 61517,62082,62650,63221,63795,64372,64952,65535
4337 : };
4338 : #endif /* SIMPLIFIED_READ */
4339 :
4340 : /* The base/delta tables are required for both read and write (but currently
4341 : * only the simplified versions.)
4342 : */
4343 : const png_uint_16 png_sRGB_base[512] =
4344 : {
4345 : 128,1782,3383,4644,5675,6564,7357,8074,
4346 : 8732,9346,9921,10463,10977,11466,11935,12384,
4347 : 12816,13233,13634,14024,14402,14769,15125,15473,
4348 : 15812,16142,16466,16781,17090,17393,17690,17981,
4349 : 18266,18546,18822,19093,19359,19621,19879,20133,
4350 : 20383,20630,20873,21113,21349,21583,21813,22041,
4351 : 22265,22487,22707,22923,23138,23350,23559,23767,
4352 : 23972,24175,24376,24575,24772,24967,25160,25352,
4353 : 25542,25730,25916,26101,26284,26465,26645,26823,
4354 : 27000,27176,27350,27523,27695,27865,28034,28201,
4355 : 28368,28533,28697,28860,29021,29182,29341,29500,
4356 : 29657,29813,29969,30123,30276,30429,30580,30730,
4357 : 30880,31028,31176,31323,31469,31614,31758,31902,
4358 : 32045,32186,32327,32468,32607,32746,32884,33021,
4359 : 33158,33294,33429,33564,33697,33831,33963,34095,
4360 : 34226,34357,34486,34616,34744,34873,35000,35127,
4361 : 35253,35379,35504,35629,35753,35876,35999,36122,
4362 : 36244,36365,36486,36606,36726,36845,36964,37083,
4363 : 37201,37318,37435,37551,37668,37783,37898,38013,
4364 : 38127,38241,38354,38467,38580,38692,38803,38915,
4365 : 39026,39136,39246,39356,39465,39574,39682,39790,
4366 : 39898,40005,40112,40219,40325,40431,40537,40642,
4367 : 40747,40851,40955,41059,41163,41266,41369,41471,
4368 : 41573,41675,41777,41878,41979,42079,42179,42279,
4369 : 42379,42478,42577,42676,42775,42873,42971,43068,
4370 : 43165,43262,43359,43456,43552,43648,43743,43839,
4371 : 43934,44028,44123,44217,44311,44405,44499,44592,
4372 : 44685,44778,44870,44962,45054,45146,45238,45329,
4373 : 45420,45511,45601,45692,45782,45872,45961,46051,
4374 : 46140,46229,46318,46406,46494,46583,46670,46758,
4375 : 46846,46933,47020,47107,47193,47280,47366,47452,
4376 : 47538,47623,47709,47794,47879,47964,48048,48133,
4377 : 48217,48301,48385,48468,48552,48635,48718,48801,
4378 : 48884,48966,49048,49131,49213,49294,49376,49458,
4379 : 49539,49620,49701,49782,49862,49943,50023,50103,
4380 : 50183,50263,50342,50422,50501,50580,50659,50738,
4381 : 50816,50895,50973,51051,51129,51207,51285,51362,
4382 : 51439,51517,51594,51671,51747,51824,51900,51977,
4383 : 52053,52129,52205,52280,52356,52432,52507,52582,
4384 : 52657,52732,52807,52881,52956,53030,53104,53178,
4385 : 53252,53326,53400,53473,53546,53620,53693,53766,
4386 : 53839,53911,53984,54056,54129,54201,54273,54345,
4387 : 54417,54489,54560,54632,54703,54774,54845,54916,
4388 : 54987,55058,55129,55199,55269,55340,55410,55480,
4389 : 55550,55620,55689,55759,55828,55898,55967,56036,
4390 : 56105,56174,56243,56311,56380,56448,56517,56585,
4391 : 56653,56721,56789,56857,56924,56992,57059,57127,
4392 : 57194,57261,57328,57395,57462,57529,57595,57662,
4393 : 57728,57795,57861,57927,57993,58059,58125,58191,
4394 : 58256,58322,58387,58453,58518,58583,58648,58713,
4395 : 58778,58843,58908,58972,59037,59101,59165,59230,
4396 : 59294,59358,59422,59486,59549,59613,59677,59740,
4397 : 59804,59867,59930,59993,60056,60119,60182,60245,
4398 : 60308,60370,60433,60495,60558,60620,60682,60744,
4399 : 60806,60868,60930,60992,61054,61115,61177,61238,
4400 : 61300,61361,61422,61483,61544,61605,61666,61727,
4401 : 61788,61848,61909,61969,62030,62090,62150,62211,
4402 : 62271,62331,62391,62450,62510,62570,62630,62689,
4403 : 62749,62808,62867,62927,62986,63045,63104,63163,
4404 : 63222,63281,63340,63398,63457,63515,63574,63632,
4405 : 63691,63749,63807,63865,63923,63981,64039,64097,
4406 : 64155,64212,64270,64328,64385,64443,64500,64557,
4407 : 64614,64672,64729,64786,64843,64900,64956,65013,
4408 : 65070,65126,65183,65239,65296,65352,65409,65465
4409 : };
4410 :
4411 : const png_byte png_sRGB_delta[512] =
4412 : {
4413 : 207,201,158,129,113,100,90,82,77,72,68,64,61,59,56,54,
4414 : 52,50,49,47,46,45,43,42,41,40,39,39,38,37,36,36,
4415 : 35,34,34,33,33,32,32,31,31,30,30,30,29,29,28,28,
4416 : 28,27,27,27,27,26,26,26,25,25,25,25,24,24,24,24,
4417 : 23,23,23,23,23,22,22,22,22,22,22,21,21,21,21,21,
4418 : 21,20,20,20,20,20,20,20,20,19,19,19,19,19,19,19,
4419 : 19,18,18,18,18,18,18,18,18,18,18,17,17,17,17,17,
4420 : 17,17,17,17,17,17,16,16,16,16,16,16,16,16,16,16,
4421 : 16,16,16,16,15,15,15,15,15,15,15,15,15,15,15,15,
4422 : 15,15,15,15,14,14,14,14,14,14,14,14,14,14,14,14,
4423 : 14,14,14,14,14,14,14,13,13,13,13,13,13,13,13,13,
4424 : 13,13,13,13,13,13,13,13,13,13,13,13,13,13,12,12,
4425 : 12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,
4426 : 12,12,12,12,12,12,12,12,12,12,12,12,11,11,11,11,
4427 : 11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,
4428 : 11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,
4429 : 11,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,
4430 : 10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,
4431 : 10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,
4432 : 10,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
4433 : 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
4434 : 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
4435 : 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
4436 : 9,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
4437 : 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
4438 : 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
4439 : 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
4440 : 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
4441 : 8,8,8,8,8,8,8,8,8,7,7,7,7,7,7,7,
4442 : 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
4443 : 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
4444 : 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7
4445 : };
4446 : #endif /* SIMPLIFIED READ/WRITE sRGB support */
4447 :
4448 : /* SIMPLIFIED READ/WRITE SUPPORT */
4449 : #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
4450 : defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
4451 : static int
4452 : png_image_free_function(png_voidp argument)
4453 : {
4454 : png_imagep image = png_voidcast(png_imagep, argument);
4455 : png_controlp cp = image->opaque;
4456 : png_control c;
4457 :
4458 : /* Double check that we have a png_ptr - it should be impossible to get here
4459 : * without one.
4460 : */
4461 : if (cp->png_ptr == NULL)
4462 : return 0;
4463 :
4464 : /* First free any data held in the control structure. */
4465 : # ifdef PNG_STDIO_SUPPORTED
4466 : if (cp->owned_file != 0)
4467 : {
4468 : FILE *fp = png_voidcast(FILE*, cp->png_ptr->io_ptr);
4469 : cp->owned_file = 0;
4470 :
4471 : /* Ignore errors here. */
4472 : if (fp != NULL)
4473 : {
4474 : cp->png_ptr->io_ptr = NULL;
4475 : (void)fclose(fp);
4476 : }
4477 : }
4478 : # endif
4479 :
4480 : /* Copy the control structure so that the original, allocated, version can be
4481 : * safely freed. Notice that a png_error here stops the remainder of the
4482 : * cleanup, but this is probably fine because that would indicate bad memory
4483 : * problems anyway.
4484 : */
4485 : c = *cp;
4486 : image->opaque = &c;
4487 : png_free(c.png_ptr, cp);
4488 :
4489 : /* Then the structures, calling the correct API. */
4490 : if (c.for_write != 0)
4491 : {
4492 : # ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
4493 : png_destroy_write_struct(&c.png_ptr, &c.info_ptr);
4494 : # else
4495 : png_error(c.png_ptr, "simplified write not supported");
4496 : # endif
4497 : }
4498 : else
4499 : {
4500 : # ifdef PNG_SIMPLIFIED_READ_SUPPORTED
4501 : png_destroy_read_struct(&c.png_ptr, &c.info_ptr, NULL);
4502 : # else
4503 : png_error(c.png_ptr, "simplified read not supported");
4504 : # endif
4505 : }
4506 :
4507 : /* Success. */
4508 : return 1;
4509 : }
4510 :
4511 : void PNGAPI
4512 : png_image_free(png_imagep image)
4513 : {
4514 : /* Safely call the real function, but only if doing so is safe at this point
4515 : * (if not inside an error handling context). Otherwise assume
4516 : * png_safe_execute will call this API after the return.
4517 : */
4518 : if (image != NULL && image->opaque != NULL &&
4519 : image->opaque->error_buf == NULL)
4520 : {
4521 : /* Ignore errors here: */
4522 : (void)png_safe_execute(image, png_image_free_function, image);
4523 : image->opaque = NULL;
4524 : }
4525 : }
4526 :
4527 : int /* PRIVATE */
4528 : png_image_error(png_imagep image, png_const_charp error_message)
4529 : {
4530 : /* Utility to log an error. */
4531 : png_safecat(image->message, (sizeof image->message), 0, error_message);
4532 : image->warning_or_error |= PNG_IMAGE_ERROR;
4533 : png_image_free(image);
4534 : return 0;
4535 : }
4536 :
4537 : #endif /* SIMPLIFIED READ/WRITE */
4538 : #endif /* READ || WRITE */
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