1
2 /* png.c - location for general purpose libpng functions
3 *
4 * libpng version 1.2.8 - December 3, 2004
5 * For conditions of distribution and use, see copyright notice in png.h
6 * Copyright (c) 1998-2004 Glenn Randers-Pehrson
7 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
8 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
9 */
10
11 #define PNG_INTERNAL
12 #define PNG_NO_EXTERN
13 #include "png.h"
14
15 /* Generate a compiler error if there is an old png.h in the search path. */
16 typedef version_1_2_8 Your_png_h_is_not_version_1_2_8;
17
18 /* Version information for C files. This had better match the version
19 * string defined in png.h. */
20
21 #ifdef PNG_USE_GLOBAL_ARRAYS
22 /* png_libpng_ver was changed to a function in version 1.0.5c */
23 const char png_libpng_ver[18] = PNG_LIBPNG_VER_STRING;
24
25 /* png_sig was changed to a function in version 1.0.5c */
26 /* Place to hold the signature string for a PNG file. */
27 const png_byte FARDATA png_sig[8] = {137, 80, 78, 71, 13, 10, 26, 10};
28
29 /* Invoke global declarations for constant strings for known chunk types */
30 PNG_IHDR;
31 PNG_IDAT;
32 PNG_IEND;
33 PNG_PLTE;
34 PNG_bKGD;
35 PNG_cHRM;
36 PNG_gAMA;
37 PNG_hIST;
38 PNG_iCCP;
39 PNG_iTXt;
40 PNG_oFFs;
41 PNG_pCAL;
42 PNG_sCAL;
43 PNG_pHYs;
44 PNG_sBIT;
45 PNG_sPLT;
46 PNG_sRGB;
47 PNG_tEXt;
48 PNG_tIME;
49 PNG_tRNS;
50 PNG_zTXt;
51
52 /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
53
54 /* start of interlace block */
55 const int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
56
57 /* offset to next interlace block */
58 const int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
59
60 /* start of interlace block in the y direction */
61 const int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
62
63 /* offset to next interlace block in the y direction */
64 const int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
65
66 /* width of interlace block (used in assembler routines only) */
67 #ifdef PNG_HAVE_ASSEMBLER_COMBINE_ROW
68 const int FARDATA png_pass_width[] = {8, 4, 4, 2, 2, 1, 1};
69 #endif
70
71 /* Height of interlace block. This is not currently used - if you need
72 * it, uncomment it here and in png.h
73 const int FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
74 */
75
76 /* Mask to determine which pixels are valid in a pass */
77 const int FARDATA png_pass_mask[] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
78
79 /* Mask to determine which pixels to overwrite while displaying */
80 const int FARDATA png_pass_dsp_mask[]
81 = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
82
83 #endif /* PNG_USE_GLOBAL_ARRAYS */
84
85 /* Tells libpng that we have already handled the first "num_bytes" bytes
86 * of the PNG file signature. If the PNG data is embedded into another
87 * stream we can set num_bytes = 8 so that libpng will not attempt to read
88 * or write any of the magic bytes before it starts on the IHDR.
89 */
90
91 void PNGAPI
png_set_sig_bytes(png_structp png_ptr,int num_bytes)92 png_set_sig_bytes(png_structp png_ptr, int num_bytes)
93 {
94 png_debug(1, "in png_set_sig_bytes\n");
95 if (num_bytes > 8)
96 png_error(png_ptr, "Too many bytes for PNG signature.");
97
98 png_ptr->sig_bytes = (png_byte)(num_bytes < 0 ? 0 : num_bytes);
99 }
100
101 /* Checks whether the supplied bytes match the PNG signature. We allow
102 * checking less than the full 8-byte signature so that those apps that
103 * already read the first few bytes of a file to determine the file type
104 * can simply check the remaining bytes for extra assurance. Returns
105 * an integer less than, equal to, or greater than zero if sig is found,
106 * respectively, to be less than, to match, or be greater than the correct
107 * PNG signature (this is the same behaviour as strcmp, memcmp, etc).
108 */
109 int PNGAPI
png_sig_cmp(png_bytep sig,png_size_t start,png_size_t num_to_check)110 png_sig_cmp(png_bytep sig, png_size_t start, png_size_t num_to_check)
111 {
112 png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
113 if (num_to_check > 8)
114 num_to_check = 8;
115 else if (num_to_check < 1)
116 return (0);
117
118 if (start > 7)
119 return (0);
120
121 if (start + num_to_check > 8)
122 num_to_check = 8 - start;
123
124 return ((int)(png_memcmp(&sig[start], &png_signature[start], num_to_check)));
125 }
126
127 /* (Obsolete) function to check signature bytes. It does not allow one
128 * to check a partial signature. This function might be removed in the
129 * future - use png_sig_cmp(). Returns true (nonzero) if the file is a PNG.
130 */
131 int PNGAPI
png_check_sig(png_bytep sig,int num)132 png_check_sig(png_bytep sig, int num)
133 {
134 return ((int)!png_sig_cmp(sig, (png_size_t)0, (png_size_t)num));
135 }
136
137 /* Function to allocate memory for zlib and clear it to 0. */
138 #ifdef PNG_1_0_X
139 voidpf PNGAPI
140 #else
141 voidpf /* private */
142 #endif
png_zalloc(voidpf png_ptr,uInt items,uInt size)143 png_zalloc(voidpf png_ptr, uInt items, uInt size)
144 {
145 png_voidp ptr;
146 png_structp p=png_ptr;
147 png_uint_32 save_flags=p->flags;
148 png_uint_32 num_bytes;
149
150 if (items > PNG_UINT_32_MAX/size)
151 {
152 png_warning (png_ptr, "Potential overflow in png_zalloc()");
153 return (NULL);
154 }
155 num_bytes = (png_uint_32)items * size;
156
157 p->flags|=PNG_FLAG_MALLOC_NULL_MEM_OK;
158 ptr = (png_voidp)png_malloc((png_structp)png_ptr, num_bytes);
159 p->flags=save_flags;
160
161 #if defined(PNG_1_0_X) && !defined(PNG_NO_ZALLOC_ZERO)
162 if (ptr == NULL)
163 return ((voidpf)ptr);
164
165 if (num_bytes > (png_uint_32)0x8000L)
166 {
167 png_memset(ptr, 0, (png_size_t)0x8000L);
168 png_memset((png_bytep)ptr + (png_size_t)0x8000L, 0,
169 (png_size_t)(num_bytes - (png_uint_32)0x8000L));
170 }
171 else
172 {
173 png_memset(ptr, 0, (png_size_t)num_bytes);
174 }
175 #endif
176 return ((voidpf)ptr);
177 }
178
179 /* function to free memory for zlib */
180 #ifdef PNG_1_0_X
181 void PNGAPI
182 #else
183 void /* private */
184 #endif
png_zfree(voidpf png_ptr,voidpf ptr)185 png_zfree(voidpf png_ptr, voidpf ptr)
186 {
187 png_free((png_structp)png_ptr, (png_voidp)ptr);
188 }
189
190 /* Reset the CRC variable to 32 bits of 1's. Care must be taken
191 * in case CRC is > 32 bits to leave the top bits 0.
192 */
193 void /* PRIVATE */
png_reset_crc(png_structp png_ptr)194 png_reset_crc(png_structp png_ptr)
195 {
196 png_ptr->crc = crc32(0, Z_NULL, 0);
197 }
198
199 /* Calculate the CRC over a section of data. We can only pass as
200 * much data to this routine as the largest single buffer size. We
201 * also check that this data will actually be used before going to the
202 * trouble of calculating it.
203 */
204 void /* PRIVATE */
png_calculate_crc(png_structp png_ptr,png_bytep ptr,png_size_t length)205 png_calculate_crc(png_structp png_ptr, png_bytep ptr, png_size_t length)
206 {
207 int need_crc = 1;
208
209 if (png_ptr->chunk_name[0] & 0x20) /* ancillary */
210 {
211 if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
212 (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
213 need_crc = 0;
214 }
215 else /* critical */
216 {
217 if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE)
218 need_crc = 0;
219 }
220
221 if (need_crc)
222 png_ptr->crc = crc32(png_ptr->crc, ptr, (uInt)length);
223 }
224
225 /* Allocate the memory for an info_struct for the application. We don't
226 * really need the png_ptr, but it could potentially be useful in the
227 * future. This should be used in favour of malloc(png_sizeof(png_info))
228 * and png_info_init() so that applications that want to use a shared
229 * libpng don't have to be recompiled if png_info changes size.
230 */
231 png_infop PNGAPI
png_create_info_struct(png_structp png_ptr)232 png_create_info_struct(png_structp png_ptr)
233 {
234 png_infop info_ptr;
235
236 png_debug(1, "in png_create_info_struct\n");
237 if(png_ptr == NULL) return (NULL);
238 #ifdef PNG_USER_MEM_SUPPORTED
239 info_ptr = (png_infop)png_create_struct_2(PNG_STRUCT_INFO,
240 png_ptr->malloc_fn, png_ptr->mem_ptr);
241 #else
242 info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO);
243 #endif
244 if (info_ptr != NULL)
245 png_info_init_3(&info_ptr, png_sizeof(png_info));
246
247 return (info_ptr);
248 }
249
250 /* This function frees the memory associated with a single info struct.
251 * Normally, one would use either png_destroy_read_struct() or
252 * png_destroy_write_struct() to free an info struct, but this may be
253 * useful for some applications.
254 */
255 void PNGAPI
png_destroy_info_struct(png_structp png_ptr,png_infopp info_ptr_ptr)256 png_destroy_info_struct(png_structp png_ptr, png_infopp info_ptr_ptr)
257 {
258 png_infop info_ptr = NULL;
259
260 png_debug(1, "in png_destroy_info_struct\n");
261 if (info_ptr_ptr != NULL)
262 info_ptr = *info_ptr_ptr;
263
264 if (info_ptr != NULL)
265 {
266 png_info_destroy(png_ptr, info_ptr);
267
268 #ifdef PNG_USER_MEM_SUPPORTED
269 png_destroy_struct_2((png_voidp)info_ptr, png_ptr->free_fn,
270 png_ptr->mem_ptr);
271 #else
272 png_destroy_struct((png_voidp)info_ptr);
273 #endif
274 *info_ptr_ptr = NULL;
275 }
276 }
277
278 /* Initialize the info structure. This is now an internal function (0.89)
279 * and applications using it are urged to use png_create_info_struct()
280 * instead.
281 */
282 #if defined(PNG_1_0_X) || defined (PNG_1_2_X)
283 #undef png_info_init
284 void PNGAPI
png_info_init(png_infop info_ptr)285 png_info_init(png_infop info_ptr)
286 {
287 /* We only come here via pre-1.0.12-compiled applications */
288 png_info_init_3(&info_ptr, 0);
289 }
290 #endif
291
292 void PNGAPI
png_info_init_3(png_infopp ptr_ptr,png_size_t png_info_struct_size)293 png_info_init_3(png_infopp ptr_ptr, png_size_t png_info_struct_size)
294 {
295 png_infop info_ptr = *ptr_ptr;
296
297 png_debug(1, "in png_info_init_3\n");
298
299 if(png_sizeof(png_info) > png_info_struct_size)
300 {
301 png_destroy_struct(info_ptr);
302 info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO);
303 *ptr_ptr = info_ptr;
304 }
305
306 /* set everything to 0 */
307 png_memset(info_ptr, 0, png_sizeof (png_info));
308 }
309
310 #ifdef PNG_FREE_ME_SUPPORTED
311 void PNGAPI
png_data_freer(png_structp png_ptr,png_infop info_ptr,int freer,png_uint_32 mask)312 png_data_freer(png_structp png_ptr, png_infop info_ptr,
313 int freer, png_uint_32 mask)
314 {
315 png_debug(1, "in png_data_freer\n");
316 if (png_ptr == NULL || info_ptr == NULL)
317 return;
318 if(freer == PNG_DESTROY_WILL_FREE_DATA)
319 info_ptr->free_me |= mask;
320 else if(freer == PNG_USER_WILL_FREE_DATA)
321 info_ptr->free_me &= ~mask;
322 else
323 png_warning(png_ptr,
324 "Unknown freer parameter in png_data_freer.");
325 }
326 #endif
327
328 void PNGAPI
png_free_data(png_structp png_ptr,png_infop info_ptr,png_uint_32 mask,int num)329 png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask,
330 int num)
331 {
332 png_debug(1, "in png_free_data\n");
333 if (png_ptr == NULL || info_ptr == NULL)
334 return;
335
336 #if defined(PNG_TEXT_SUPPORTED)
337 /* free text item num or (if num == -1) all text items */
338 #ifdef PNG_FREE_ME_SUPPORTED
339 if ((mask & PNG_FREE_TEXT) & info_ptr->free_me)
340 #else
341 if (mask & PNG_FREE_TEXT)
342 #endif
343 {
344 if (num != -1)
345 {
346 if (info_ptr->text && info_ptr->text[num].key)
347 {
348 png_free(png_ptr, info_ptr->text[num].key);
349 info_ptr->text[num].key = NULL;
350 }
351 }
352 else
353 {
354 int i;
355 for (i = 0; i < info_ptr->num_text; i++)
356 png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, i);
357 png_free(png_ptr, info_ptr->text);
358 info_ptr->text = NULL;
359 info_ptr->num_text=0;
360 }
361 }
362 #endif
363
364 #if defined(PNG_tRNS_SUPPORTED)
365 /* free any tRNS entry */
366 #ifdef PNG_FREE_ME_SUPPORTED
367 if ((mask & PNG_FREE_TRNS) & info_ptr->free_me)
368 #else
369 if ((mask & PNG_FREE_TRNS) && (png_ptr->flags & PNG_FLAG_FREE_TRNS))
370 #endif
371 {
372 png_free(png_ptr, info_ptr->trans);
373 info_ptr->valid &= ~PNG_INFO_tRNS;
374 #ifndef PNG_FREE_ME_SUPPORTED
375 png_ptr->flags &= ~PNG_FLAG_FREE_TRNS;
376 #endif
377 info_ptr->trans = NULL;
378 }
379 #endif
380
381 #if defined(PNG_sCAL_SUPPORTED)
382 /* free any sCAL entry */
383 #ifdef PNG_FREE_ME_SUPPORTED
384 if ((mask & PNG_FREE_SCAL) & info_ptr->free_me)
385 #else
386 if (mask & PNG_FREE_SCAL)
387 #endif
388 {
389 #if defined(PNG_FIXED_POINT_SUPPORTED) && !defined(PNG_FLOATING_POINT_SUPPORTED)
390 png_free(png_ptr, info_ptr->scal_s_width);
391 png_free(png_ptr, info_ptr->scal_s_height);
392 info_ptr->scal_s_width = NULL;
393 info_ptr->scal_s_height = NULL;
394 #endif
395 info_ptr->valid &= ~PNG_INFO_sCAL;
396 }
397 #endif
398
399 #if defined(PNG_pCAL_SUPPORTED)
400 /* free any pCAL entry */
401 #ifdef PNG_FREE_ME_SUPPORTED
402 if ((mask & PNG_FREE_PCAL) & info_ptr->free_me)
403 #else
404 if (mask & PNG_FREE_PCAL)
405 #endif
406 {
407 png_free(png_ptr, info_ptr->pcal_purpose);
408 png_free(png_ptr, info_ptr->pcal_units);
409 info_ptr->pcal_purpose = NULL;
410 info_ptr->pcal_units = NULL;
411 if (info_ptr->pcal_params != NULL)
412 {
413 int i;
414 for (i = 0; i < (int)info_ptr->pcal_nparams; i++)
415 {
416 png_free(png_ptr, info_ptr->pcal_params[i]);
417 info_ptr->pcal_params[i]=NULL;
418 }
419 png_free(png_ptr, info_ptr->pcal_params);
420 info_ptr->pcal_params = NULL;
421 }
422 info_ptr->valid &= ~PNG_INFO_pCAL;
423 }
424 #endif
425
426 #if defined(PNG_iCCP_SUPPORTED)
427 /* free any iCCP entry */
428 #ifdef PNG_FREE_ME_SUPPORTED
429 if ((mask & PNG_FREE_ICCP) & info_ptr->free_me)
430 #else
431 if (mask & PNG_FREE_ICCP)
432 #endif
433 {
434 png_free(png_ptr, info_ptr->iccp_name);
435 png_free(png_ptr, info_ptr->iccp_profile);
436 info_ptr->iccp_name = NULL;
437 info_ptr->iccp_profile = NULL;
438 info_ptr->valid &= ~PNG_INFO_iCCP;
439 }
440 #endif
441
442 #if defined(PNG_sPLT_SUPPORTED)
443 /* free a given sPLT entry, or (if num == -1) all sPLT entries */
444 #ifdef PNG_FREE_ME_SUPPORTED
445 if ((mask & PNG_FREE_SPLT) & info_ptr->free_me)
446 #else
447 if (mask & PNG_FREE_SPLT)
448 #endif
449 {
450 if (num != -1)
451 {
452 if(info_ptr->splt_palettes)
453 {
454 png_free(png_ptr, info_ptr->splt_palettes[num].name);
455 png_free(png_ptr, info_ptr->splt_palettes[num].entries);
456 info_ptr->splt_palettes[num].name = NULL;
457 info_ptr->splt_palettes[num].entries = NULL;
458 }
459 }
460 else
461 {
462 if(info_ptr->splt_palettes_num)
463 {
464 int i;
465 for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
466 png_free_data(png_ptr, info_ptr, PNG_FREE_SPLT, i);
467
468 png_free(png_ptr, info_ptr->splt_palettes);
469 info_ptr->splt_palettes = NULL;
470 info_ptr->splt_palettes_num = 0;
471 }
472 info_ptr->valid &= ~PNG_INFO_sPLT;
473 }
474 }
475 #endif
476
477 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
478 #ifdef PNG_FREE_ME_SUPPORTED
479 if ((mask & PNG_FREE_UNKN) & info_ptr->free_me)
480 #else
481 if (mask & PNG_FREE_UNKN)
482 #endif
483 {
484 if (num != -1)
485 {
486 if(info_ptr->unknown_chunks)
487 {
488 png_free(png_ptr, info_ptr->unknown_chunks[num].data);
489 info_ptr->unknown_chunks[num].data = NULL;
490 }
491 }
492 else
493 {
494 int i;
495
496 if(info_ptr->unknown_chunks_num)
497 {
498 for (i = 0; i < (int)info_ptr->unknown_chunks_num; i++)
499 png_free_data(png_ptr, info_ptr, PNG_FREE_UNKN, i);
500
501 png_free(png_ptr, info_ptr->unknown_chunks);
502 info_ptr->unknown_chunks = NULL;
503 info_ptr->unknown_chunks_num = 0;
504 }
505 }
506 }
507 #endif
508
509 #if defined(PNG_hIST_SUPPORTED)
510 /* free any hIST entry */
511 #ifdef PNG_FREE_ME_SUPPORTED
512 if ((mask & PNG_FREE_HIST) & info_ptr->free_me)
513 #else
514 if ((mask & PNG_FREE_HIST) && (png_ptr->flags & PNG_FLAG_FREE_HIST))
515 #endif
516 {
517 png_free(png_ptr, info_ptr->hist);
518 info_ptr->hist = NULL;
519 info_ptr->valid &= ~PNG_INFO_hIST;
520 #ifndef PNG_FREE_ME_SUPPORTED
521 png_ptr->flags &= ~PNG_FLAG_FREE_HIST;
522 #endif
523 }
524 #endif
525
526 /* free any PLTE entry that was internally allocated */
527 #ifdef PNG_FREE_ME_SUPPORTED
528 if ((mask & PNG_FREE_PLTE) & info_ptr->free_me)
529 #else
530 if ((mask & PNG_FREE_PLTE) && (png_ptr->flags & PNG_FLAG_FREE_PLTE))
531 #endif
532 {
533 png_zfree(png_ptr, info_ptr->palette);
534 info_ptr->palette = NULL;
535 info_ptr->valid &= ~PNG_INFO_PLTE;
536 #ifndef PNG_FREE_ME_SUPPORTED
537 png_ptr->flags &= ~PNG_FLAG_FREE_PLTE;
538 #endif
539 info_ptr->num_palette = 0;
540 }
541
542 #if defined(PNG_INFO_IMAGE_SUPPORTED)
543 /* free any image bits attached to the info structure */
544 #ifdef PNG_FREE_ME_SUPPORTED
545 if ((mask & PNG_FREE_ROWS) & info_ptr->free_me)
546 #else
547 if (mask & PNG_FREE_ROWS)
548 #endif
549 {
550 if(info_ptr->row_pointers)
551 {
552 int row;
553 for (row = 0; row < (int)info_ptr->height; row++)
554 {
555 png_free(png_ptr, info_ptr->row_pointers[row]);
556 info_ptr->row_pointers[row]=NULL;
557 }
558 png_free(png_ptr, info_ptr->row_pointers);
559 info_ptr->row_pointers=NULL;
560 }
561 info_ptr->valid &= ~PNG_INFO_IDAT;
562 }
563 #endif
564
565 #ifdef PNG_FREE_ME_SUPPORTED
566 if(num == -1)
567 info_ptr->free_me &= ~mask;
568 else
569 info_ptr->free_me &= ~(mask & ~PNG_FREE_MUL);
570 #endif
571 }
572
573 /* This is an internal routine to free any memory that the info struct is
574 * pointing to before re-using it or freeing the struct itself. Recall
575 * that png_free() checks for NULL pointers for us.
576 */
577 void /* PRIVATE */
png_info_destroy(png_structp png_ptr,png_infop info_ptr)578 png_info_destroy(png_structp png_ptr, png_infop info_ptr)
579 {
580 png_debug(1, "in png_info_destroy\n");
581
582 png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
583
584 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
585 if (png_ptr->num_chunk_list)
586 {
587 png_free(png_ptr, png_ptr->chunk_list);
588 png_ptr->chunk_list=NULL;
589 png_ptr->num_chunk_list=0;
590 }
591 #endif
592
593 png_info_init_3(&info_ptr, png_sizeof(png_info));
594 }
595
596 /* This function returns a pointer to the io_ptr associated with the user
597 * functions. The application should free any memory associated with this
598 * pointer before png_write_destroy() or png_read_destroy() are called.
599 */
600 png_voidp PNGAPI
png_get_io_ptr(png_structp png_ptr)601 png_get_io_ptr(png_structp png_ptr)
602 {
603 return (png_ptr->io_ptr);
604 }
605
606 #if !defined(PNG_NO_STDIO)
607 /* Initialize the default input/output functions for the PNG file. If you
608 * use your own read or write routines, you can call either png_set_read_fn()
609 * or png_set_write_fn() instead of png_init_io(). If you have defined
610 * PNG_NO_STDIO, you must use a function of your own because "FILE *" isn't
611 * necessarily available.
612 */
613 void PNGAPI
png_init_io(png_structp png_ptr,png_FILE_p fp)614 png_init_io(png_structp png_ptr, png_FILE_p fp)
615 {
616 png_debug(1, "in png_init_io\n");
617 png_ptr->io_ptr = (png_voidp)fp;
618 }
619 #endif
620
621 #if defined(PNG_TIME_RFC1123_SUPPORTED)
622 /* Convert the supplied time into an RFC 1123 string suitable for use in
623 * a "Creation Time" or other text-based time string.
624 */
625 png_charp PNGAPI
png_convert_to_rfc1123(png_structp png_ptr,png_timep ptime)626 png_convert_to_rfc1123(png_structp png_ptr, png_timep ptime)
627 {
628 static PNG_CONST char short_months[12][4] =
629 {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
630 "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
631
632 if (png_ptr->time_buffer == NULL)
633 {
634 png_ptr->time_buffer = (png_charp)png_malloc(png_ptr, (png_uint_32)(29*
635 png_sizeof(char)));
636 }
637
638 #if defined(_WIN32_WCE)
639 {
640 wchar_t time_buf[29];
641 wsprintf(time_buf, TEXT("%d %S %d %02d:%02d:%02d +0000"),
642 ptime->day % 32, short_months[(ptime->month - 1) % 12],
643 ptime->year, ptime->hour % 24, ptime->minute % 60,
644 ptime->second % 61);
645 WideCharToMultiByte(CP_ACP, 0, time_buf, -1, png_ptr->time_buffer, 29,
646 NULL, NULL);
647 }
648 #else
649 #ifdef USE_FAR_KEYWORD
650 {
651 char near_time_buf[29];
652 sprintf(near_time_buf, "%d %s %d %02d:%02d:%02d +0000",
653 ptime->day % 32, short_months[(ptime->month - 1) % 12],
654 ptime->year, ptime->hour % 24, ptime->minute % 60,
655 ptime->second % 61);
656 png_memcpy(png_ptr->time_buffer, near_time_buf,
657 29*png_sizeof(char));
658 }
659 #else
660 sprintf(png_ptr->time_buffer, "%d %s %d %02d:%02d:%02d +0000",
661 ptime->day % 32, short_months[(ptime->month - 1) % 12],
662 ptime->year, ptime->hour % 24, ptime->minute % 60,
663 ptime->second % 61);
664 #endif
665 #endif /* _WIN32_WCE */
666 return ((png_charp)png_ptr->time_buffer);
667 }
668 #endif /* PNG_TIME_RFC1123_SUPPORTED */
669
670 #if 0
671 /* Signature string for a PNG file. */
672 png_bytep PNGAPI
673 png_sig_bytes(void)
674 {
675 return ((png_bytep)"\211\120\116\107\015\012\032\012");
676 }
677 #endif
678
679 png_charp PNGAPI
png_get_copyright(png_structp png_ptr)680 png_get_copyright(png_structp png_ptr)
681 {
682 if (&png_ptr != NULL) /* silence compiler warning about unused png_ptr */
683 return ((png_charp) "\n libpng version 1.2.8 - December 3, 2004\n\
684 Copyright (c) 1998-2004 Glenn Randers-Pehrson\n\
685 Copyright (c) 1996-1997 Andreas Dilger\n\
686 Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.\n");
687 return ((png_charp) "");
688 }
689
690 /* The following return the library version as a short string in the
691 * format 1.0.0 through 99.99.99zz. To get the version of *.h files
692 * used with your application, print out PNG_LIBPNG_VER_STRING, which
693 * is defined in png.h.
694 * Note: now there is no difference between png_get_libpng_ver() and
695 * png_get_header_ver(). Due to the version_nn_nn_nn typedef guard,
696 * it is guaranteed that png.c uses the correct version of png.h.
697 */
698 png_charp PNGAPI
png_get_libpng_ver(png_structp png_ptr)699 png_get_libpng_ver(png_structp png_ptr)
700 {
701 /* Version of *.c files used when building libpng */
702 if (&png_ptr != NULL) /* silence compiler warning about unused png_ptr */
703 return ((png_charp) PNG_LIBPNG_VER_STRING);
704 return ((png_charp) "");
705 }
706
707 png_charp PNGAPI
png_get_header_ver(png_structp png_ptr)708 png_get_header_ver(png_structp png_ptr)
709 {
710 /* Version of *.h files used when building libpng */
711 if (&png_ptr != NULL) /* silence compiler warning about unused png_ptr */
712 return ((png_charp) PNG_LIBPNG_VER_STRING);
713 return ((png_charp) "");
714 }
715
716 png_charp PNGAPI
png_get_header_version(png_structp png_ptr)717 png_get_header_version(png_structp png_ptr)
718 {
719 /* Returns longer string containing both version and date */
720 if (&png_ptr != NULL) /* silence compiler warning about unused png_ptr */
721 return ((png_charp) PNG_HEADER_VERSION_STRING);
722 return ((png_charp) "");
723 }
724
725 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
726 int PNGAPI
png_handle_as_unknown(png_structp png_ptr,png_bytep chunk_name)727 png_handle_as_unknown(png_structp png_ptr, png_bytep chunk_name)
728 {
729 /* check chunk_name and return "keep" value if it's on the list, else 0 */
730 int i;
731 png_bytep p;
732 if((png_ptr == NULL && chunk_name == NULL) || png_ptr->num_chunk_list<=0)
733 return 0;
734 p=png_ptr->chunk_list+png_ptr->num_chunk_list*5-5;
735 for (i = png_ptr->num_chunk_list; i; i--, p-=5)
736 if (!png_memcmp(chunk_name, p, 4))
737 return ((int)*(p+4));
738 return 0;
739 }
740 #endif
741
742 /* This function, added to libpng-1.0.6g, is untested. */
743 int PNGAPI
png_reset_zstream(png_structp png_ptr)744 png_reset_zstream(png_structp png_ptr)
745 {
746 return (inflateReset(&png_ptr->zstream));
747 }
748
749 /* This function was added to libpng-1.0.7 */
750 png_uint_32 PNGAPI
png_access_version_number(void)751 png_access_version_number(void)
752 {
753 /* Version of *.c files used when building libpng */
754 return((png_uint_32) PNG_LIBPNG_VER);
755 }
756
757
758 #if !defined(PNG_1_0_X)
759 #if defined(PNG_ASSEMBLER_CODE_SUPPORTED)
760 /* GRR: could add this: && defined(PNG_MMX_CODE_SUPPORTED) */
761 /* this INTERNAL function was added to libpng 1.2.0 */
762 void /* PRIVATE */
png_init_mmx_flags(png_structp png_ptr)763 png_init_mmx_flags (png_structp png_ptr)
764 {
765 png_ptr->mmx_rowbytes_threshold = 0;
766 png_ptr->mmx_bitdepth_threshold = 0;
767
768 # if (defined(PNG_USE_PNGVCRD) || defined(PNG_USE_PNGGCCRD))
769
770 png_ptr->asm_flags |= PNG_ASM_FLAG_MMX_SUPPORT_COMPILED;
771
772 if (png_mmx_support() > 0) {
773 png_ptr->asm_flags |= PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
774 # ifdef PNG_HAVE_ASSEMBLER_COMBINE_ROW
775 | PNG_ASM_FLAG_MMX_READ_COMBINE_ROW
776 # endif
777 # ifdef PNG_HAVE_ASSEMBLER_READ_INTERLACE
778 | PNG_ASM_FLAG_MMX_READ_INTERLACE
779 # endif
780 # ifndef PNG_HAVE_ASSEMBLER_READ_FILTER_ROW
781 ;
782 # else
783 | PNG_ASM_FLAG_MMX_READ_FILTER_SUB
784 | PNG_ASM_FLAG_MMX_READ_FILTER_UP
785 | PNG_ASM_FLAG_MMX_READ_FILTER_AVG
786 | PNG_ASM_FLAG_MMX_READ_FILTER_PAETH ;
787
788 png_ptr->mmx_rowbytes_threshold = PNG_MMX_ROWBYTES_THRESHOLD_DEFAULT;
789 png_ptr->mmx_bitdepth_threshold = PNG_MMX_BITDEPTH_THRESHOLD_DEFAULT;
790 # endif
791 } else {
792 png_ptr->asm_flags &= ~( PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
793 | PNG_MMX_READ_FLAGS
794 | PNG_MMX_WRITE_FLAGS );
795 }
796
797 # else /* !((PNGVCRD || PNGGCCRD) && PNG_ASSEMBLER_CODE_SUPPORTED)) */
798
799 /* clear all MMX flags; no support is compiled in */
800 png_ptr->asm_flags &= ~( PNG_MMX_FLAGS );
801
802 # endif /* ?(PNGVCRD || PNGGCCRD) */
803 }
804
805 #endif /* !(PNG_ASSEMBLER_CODE_SUPPORTED) */
806
807 /* this function was added to libpng 1.2.0 */
808 #if !defined(PNG_USE_PNGGCCRD) && \
809 !(defined(PNG_ASSEMBLER_CODE_SUPPORTED) && defined(PNG_USE_PNGVCRD))
810 int PNGAPI
png_mmx_support(void)811 png_mmx_support(void)
812 {
813 return -1;
814 }
815 #endif
816 #endif /* PNG_1_0_X */
817
818 #ifdef PNG_SIZE_T
819 /* Added at libpng version 1.2.6 */
820 PNG_EXTERN png_size_t PNGAPI png_convert_size PNGARG((size_t size));
821 png_size_t PNGAPI
png_convert_size(size_t size)822 png_convert_size(size_t size)
823 {
824 if (size > (png_size_t)-1)
825 PNG_ABORT(); /* We haven't got access to png_ptr, so no png_error() */
826 return ((png_size_t)size);
827 }
828 #endif /* PNG_SIZE_T */
829