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1
2/* pngread.c - read a PNG file
3 *
4 * Last changed in libpng 1.4.1 [February 25, 2010]
5 * Copyright (c) 1998-2010 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 * This file contains routines that an application calls directly to
14 * read a PNG file or stream.
15 */
16
17#define PNG_NO_PEDANTIC_WARNINGS
18#include "png.h"
19#ifdef PNG_READ_SUPPORTED
20#include "pngpriv.h"
21
22
23/* Create a PNG structure for reading, and allocate any memory needed. */
24png_structp PNGAPI
25png_create_read_struct(png_const_charp user_png_ver, png_voidp error_ptr,
26 png_error_ptr error_fn, png_error_ptr warn_fn)
27{
28
29#ifdef PNG_USER_MEM_SUPPORTED
30 return (png_create_read_struct_2(user_png_ver, error_ptr, error_fn,
31 warn_fn, NULL, NULL, NULL));
32}
33
34/* Alternate create PNG structure for reading, and allocate any memory
35 * needed.
36 */
37png_structp PNGAPI
38png_create_read_struct_2(png_const_charp user_png_ver, png_voidp error_ptr,
39 png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
40 png_malloc_ptr malloc_fn, png_free_ptr free_fn)
41{
42#endif /* PNG_USER_MEM_SUPPORTED */
43
44#ifdef PNG_SETJMP_SUPPORTED
45 volatile
46#endif
47 png_structp png_ptr;
48 volatile int png_cleanup_needed = 0;
49
50#ifdef PNG_SETJMP_SUPPORTED
51#ifdef USE_FAR_KEYWORD
52 jmp_buf jmpbuf;
53#endif
54#endif
55
56 int i;
57
58 png_debug(1, "in png_create_read_struct");
59
60#ifdef PNG_USER_MEM_SUPPORTED
61 png_ptr = (png_structp)png_create_struct_2(PNG_STRUCT_PNG,
62 malloc_fn, mem_ptr);
63#else
64 png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
65#endif
66 if (png_ptr == NULL)
67 return (NULL);
68
69 /* Added at libpng-1.2.6 */
70#ifdef PNG_USER_LIMITS_SUPPORTED
71 png_ptr->user_width_max = PNG_USER_WIDTH_MAX;
72 png_ptr->user_height_max = PNG_USER_HEIGHT_MAX;
73# ifdef PNG_USER_CHUNK_CACHE_MAX
74 /* Added at libpng-1.2.43 and 1.4.0 */
75 png_ptr->user_chunk_cache_max = PNG_USER_CHUNK_CACHE_MAX;
76# endif
77# ifdef PNG_SET_USER_CHUNK_MALLOC_MAX
78 /* Added at libpng-1.2.43 and 1.4.1 */
79 png_ptr->user_chunk_malloc_max = PNG_USER_CHUNK_MALLOC_MAX;
80# endif
81#endif
82
83#ifdef PNG_SETJMP_SUPPORTED
84/* Applications that neglect to set up their own setjmp() and then
85 encounter a png_error() will longjmp here. Since the jmpbuf is
86 then meaningless we abort instead of returning. */
87#ifdef USE_FAR_KEYWORD
88 if (setjmp(jmpbuf))
89#else
90 if (setjmp(png_jmpbuf(png_ptr))) /* Sets longjmp to match setjmp */
91#endif
92 PNG_ABORT();
93#ifdef USE_FAR_KEYWORD
94 png_memcpy(png_jmpbuf(png_ptr), jmpbuf, png_sizeof(jmp_buf));
95#endif
96#endif /* PNG_SETJMP_SUPPORTED */
97
98#ifdef PNG_USER_MEM_SUPPORTED
99 png_set_mem_fn(png_ptr, mem_ptr, malloc_fn, free_fn);
100#endif
101
102 png_set_error_fn(png_ptr, error_ptr, error_fn, warn_fn);
103
104 if (user_png_ver)
105 {
106 i = 0;
107 do
108 {
109 if (user_png_ver[i] != png_libpng_ver[i])
110 png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
111 } while (png_libpng_ver[i++]);
112 }
113 else
114 png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
115
116
117 if (png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH)
118 {
119 /* Libpng 0.90 and later are binary incompatible with libpng 0.89, so
120 * we must recompile any applications that use any older library version.
121 * For versions after libpng 1.0, we will be compatible, so we need
122 * only check the first digit.
123 */
124 if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0] ||
125 (user_png_ver[0] == '1' && user_png_ver[2] != png_libpng_ver[2]) ||
126 (user_png_ver[0] == '0' && user_png_ver[2] < '9'))
127 {
128#ifdef PNG_STDIO_SUPPORTED
129 char msg[80];
130 if (user_png_ver)
131 {
132 png_snprintf(msg, 80,
133 "Application was compiled with png.h from libpng-%.20s",
134 user_png_ver);
135 png_warning(png_ptr, msg);
136 }
137 png_snprintf(msg, 80,
138 "Application is running with png.c from libpng-%.20s",
139 png_libpng_ver);
140 png_warning(png_ptr, msg);
141#endif
142#ifdef PNG_ERROR_NUMBERS_SUPPORTED
143 png_ptr->flags = 0;
144#endif
145 png_warning(png_ptr,
146 "Incompatible libpng version in application and library");
147
148 png_cleanup_needed = 1;
149 }
150 }
151
152 if (!png_cleanup_needed)
153 {
154 /* Initialize zbuf - compression buffer */
155 png_ptr->zbuf_size = PNG_ZBUF_SIZE;
156 png_ptr->zbuf = (png_bytep)png_malloc_warn(png_ptr,
157 png_ptr->zbuf_size);
158 if (png_ptr->zbuf == NULL)
159 png_cleanup_needed = 1;
160 }
161 png_ptr->zstream.zalloc = png_zalloc;
162 png_ptr->zstream.zfree = png_zfree;
163 png_ptr->zstream.opaque = (voidpf)png_ptr;
164
165 if (!png_cleanup_needed)
166 {
167 switch (inflateInit(&png_ptr->zstream))
168 {
169 case Z_OK: /* Do nothing */ break;
170 case Z_MEM_ERROR:
171 case Z_STREAM_ERROR: png_warning(png_ptr, "zlib memory error");
172 png_cleanup_needed = 1; break;
173 case Z_VERSION_ERROR: png_warning(png_ptr, "zlib version error");
174 png_cleanup_needed = 1; break;
175 default: png_warning(png_ptr, "Unknown zlib error");
176 png_cleanup_needed = 1;
177 }
178 }
179
180 if (png_cleanup_needed)
181 {
182 /* Clean up PNG structure and deallocate any memory. */
183 png_free(png_ptr, png_ptr->zbuf);
184 png_ptr->zbuf = NULL;
185#ifdef PNG_USER_MEM_SUPPORTED
186 png_destroy_struct_2((png_voidp)png_ptr,
187 (png_free_ptr)free_fn, (png_voidp)mem_ptr);
188#else
189 png_destroy_struct((png_voidp)png_ptr);
190#endif
191 return (NULL);
192 }
193
194 png_ptr->zstream.next_out = png_ptr->zbuf;
195 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
196
197 png_set_read_fn(png_ptr, NULL, NULL);
198
199
200 return (png_ptr);
201}
202
203
204#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
205/* Read the information before the actual image data. This has been
206 * changed in v0.90 to allow reading a file that already has the magic
207 * bytes read from the stream. You can tell libpng how many bytes have
208 * been read from the beginning of the stream (up to the maximum of 8)
209 * via png_set_sig_bytes(), and we will only check the remaining bytes
210 * here. The application can then have access to the signature bytes we
211 * read if it is determined that this isn't a valid PNG file.
212 */
213void PNGAPI
214png_read_info(png_structp png_ptr, png_infop info_ptr)
215{
216 png_debug(1, "in png_read_info");
217
218 if (png_ptr == NULL || info_ptr == NULL)
219 return;
220
221 /* If we haven't checked all of the PNG signature bytes, do so now. */
222 if (png_ptr->sig_bytes < 8)
223 {
224 png_size_t num_checked = png_ptr->sig_bytes,
225 num_to_check = 8 - num_checked;
226
227#ifdef PNG_IO_STATE_SUPPORTED
228 png_ptr->io_state = PNG_IO_READING | PNG_IO_SIGNATURE;
229#endif
230
231 png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check);
232 png_ptr->sig_bytes = 8;
233
234 if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
235 {
236 if (num_checked < 4 &&
237 png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
238 png_error(png_ptr, "Not a PNG file");
239 else
240 png_error(png_ptr, "PNG file corrupted by ASCII conversion");
241 }
242 if (num_checked < 3)
243 png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
244 }
245
246 for (;;)
247 {
248 PNG_IHDR;
249 PNG_IDAT;
250 PNG_IEND;
251 PNG_PLTE;
252#ifdef PNG_READ_bKGD_SUPPORTED
253 PNG_bKGD;
254#endif
255#ifdef PNG_READ_cHRM_SUPPORTED
256 PNG_cHRM;
257#endif
258#ifdef PNG_READ_gAMA_SUPPORTED
259 PNG_gAMA;
260#endif
261#ifdef PNG_READ_hIST_SUPPORTED
262 PNG_hIST;
263#endif
264#ifdef PNG_READ_iCCP_SUPPORTED
265 PNG_iCCP;
266#endif
267#ifdef PNG_READ_iTXt_SUPPORTED
268 PNG_iTXt;
269#endif
270#ifdef PNG_READ_oFFs_SUPPORTED
271 PNG_oFFs;
272#endif
273#ifdef PNG_READ_pCAL_SUPPORTED
274 PNG_pCAL;
275#endif
276#ifdef PNG_READ_pHYs_SUPPORTED
277 PNG_pHYs;
278#endif
279#ifdef PNG_READ_sBIT_SUPPORTED
280 PNG_sBIT;
281#endif
282#ifdef PNG_READ_sCAL_SUPPORTED
283 PNG_sCAL;
284#endif
285#ifdef PNG_READ_sPLT_SUPPORTED
286 PNG_sPLT;
287#endif
288#ifdef PNG_READ_sRGB_SUPPORTED
289 PNG_sRGB;
290#endif
291#ifdef PNG_READ_tEXt_SUPPORTED
292 PNG_tEXt;
293#endif
294#ifdef PNG_READ_tIME_SUPPORTED
295 PNG_tIME;
296#endif
297#ifdef PNG_READ_tRNS_SUPPORTED
298 PNG_tRNS;
299#endif
300#ifdef PNG_READ_zTXt_SUPPORTED
301 PNG_zTXt;
302#endif
303 png_uint_32 length = png_read_chunk_header(png_ptr);
304 PNG_CONST png_bytep chunk_name = png_ptr->chunk_name;
305
306 /* This should be a binary subdivision search or a hash for
307 * matching the chunk name rather than a linear search.
308 */
309 if (!png_memcmp(chunk_name, png_IDAT, 4))
310 if (png_ptr->mode & PNG_AFTER_IDAT)
311 png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
312
313 if (!png_memcmp(chunk_name, png_IHDR, 4))
314 png_handle_IHDR(png_ptr, info_ptr, length);
315 else if (!png_memcmp(chunk_name, png_IEND, 4))
316 png_handle_IEND(png_ptr, info_ptr, length);
317#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
318 else if (png_handle_as_unknown(png_ptr, chunk_name))
319 {
320 if (!png_memcmp(chunk_name, png_IDAT, 4))
321 png_ptr->mode |= PNG_HAVE_IDAT;
322 png_handle_unknown(png_ptr, info_ptr, length);
323 if (!png_memcmp(chunk_name, png_PLTE, 4))
324 png_ptr->mode |= PNG_HAVE_PLTE;
325 else if (!png_memcmp(chunk_name, png_IDAT, 4))
326 {
327 if (!(png_ptr->mode & PNG_HAVE_IHDR))
328 png_error(png_ptr, "Missing IHDR before IDAT");
329 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
330 !(png_ptr->mode & PNG_HAVE_PLTE))
331 png_error(png_ptr, "Missing PLTE before IDAT");
332 break;
333 }
334 }
335#endif
336 else if (!png_memcmp(chunk_name, png_PLTE, 4))
337 png_handle_PLTE(png_ptr, info_ptr, length);
338 else if (!png_memcmp(chunk_name, png_IDAT, 4))
339 {
340 if (!(png_ptr->mode & PNG_HAVE_IHDR))
341 png_error(png_ptr, "Missing IHDR before IDAT");
342 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
343 !(png_ptr->mode & PNG_HAVE_PLTE))
344 png_error(png_ptr, "Missing PLTE before IDAT");
345
346 png_ptr->idat_size = length;
347 png_ptr->mode |= PNG_HAVE_IDAT;
348 break;
349 }
350#ifdef PNG_READ_bKGD_SUPPORTED
351 else if (!png_memcmp(chunk_name, png_bKGD, 4))
352 png_handle_bKGD(png_ptr, info_ptr, length);
353#endif
354#ifdef PNG_READ_cHRM_SUPPORTED
355 else if (!png_memcmp(chunk_name, png_cHRM, 4))
356 png_handle_cHRM(png_ptr, info_ptr, length);
357#endif
358#ifdef PNG_READ_gAMA_SUPPORTED
359 else if (!png_memcmp(chunk_name, png_gAMA, 4))
360 png_handle_gAMA(png_ptr, info_ptr, length);
361#endif
362#ifdef PNG_READ_hIST_SUPPORTED
363 else if (!png_memcmp(chunk_name, png_hIST, 4))
364 png_handle_hIST(png_ptr, info_ptr, length);
365#endif
366#ifdef PNG_READ_oFFs_SUPPORTED
367 else if (!png_memcmp(chunk_name, png_oFFs, 4))
368 png_handle_oFFs(png_ptr, info_ptr, length);
369#endif
370#ifdef PNG_READ_pCAL_SUPPORTED
371 else if (!png_memcmp(chunk_name, png_pCAL, 4))
372 png_handle_pCAL(png_ptr, info_ptr, length);
373#endif
374#ifdef PNG_READ_sCAL_SUPPORTED
375 else if (!png_memcmp(chunk_name, png_sCAL, 4))
376 png_handle_sCAL(png_ptr, info_ptr, length);
377#endif
378#ifdef PNG_READ_pHYs_SUPPORTED
379 else if (!png_memcmp(chunk_name, png_pHYs, 4))
380 png_handle_pHYs(png_ptr, info_ptr, length);
381#endif
382#ifdef PNG_READ_sBIT_SUPPORTED
383 else if (!png_memcmp(chunk_name, png_sBIT, 4))
384 png_handle_sBIT(png_ptr, info_ptr, length);
385#endif
386#ifdef PNG_READ_sRGB_SUPPORTED
387 else if (!png_memcmp(chunk_name, png_sRGB, 4))
388 png_handle_sRGB(png_ptr, info_ptr, length);
389#endif
390#ifdef PNG_READ_iCCP_SUPPORTED
391 else if (!png_memcmp(chunk_name, png_iCCP, 4))
392 png_handle_iCCP(png_ptr, info_ptr, length);
393#endif
394#ifdef PNG_READ_sPLT_SUPPORTED
395 else if (!png_memcmp(chunk_name, png_sPLT, 4))
396 png_handle_sPLT(png_ptr, info_ptr, length);
397#endif
398#ifdef PNG_READ_tEXt_SUPPORTED
399 else if (!png_memcmp(chunk_name, png_tEXt, 4))
400 png_handle_tEXt(png_ptr, info_ptr, length);
401#endif
402#ifdef PNG_READ_tIME_SUPPORTED
403 else if (!png_memcmp(chunk_name, png_tIME, 4))
404 png_handle_tIME(png_ptr, info_ptr, length);
405#endif
406#ifdef PNG_READ_tRNS_SUPPORTED
407 else if (!png_memcmp(chunk_name, png_tRNS, 4))
408 png_handle_tRNS(png_ptr, info_ptr, length);
409#endif
410#ifdef PNG_READ_zTXt_SUPPORTED
411 else if (!png_memcmp(chunk_name, png_zTXt, 4))
412 png_handle_zTXt(png_ptr, info_ptr, length);
413#endif
414#ifdef PNG_READ_iTXt_SUPPORTED
415 else if (!png_memcmp(chunk_name, png_iTXt, 4))
416 png_handle_iTXt(png_ptr, info_ptr, length);
417#endif
418 else
419 png_handle_unknown(png_ptr, info_ptr, length);
420 }
421}
422#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
423
424/* Optional call to update the users info_ptr structure */
425void PNGAPI
426png_read_update_info(png_structp png_ptr, png_infop info_ptr)
427{
428 png_debug(1, "in png_read_update_info");
429
430 if (png_ptr == NULL)
431 return;
432 if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
433 png_read_start_row(png_ptr);
434 else
435 png_warning(png_ptr,
436 "Ignoring extra png_read_update_info() call; row buffer not reallocated");
437
438 png_read_transform_info(png_ptr, info_ptr);
439}
440
441#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
442/* Initialize palette, background, etc, after transformations
443 * are set, but before any reading takes place. This allows
444 * the user to obtain a gamma-corrected palette, for example.
445 * If the user doesn't call this, we will do it ourselves.
446 */
447void PNGAPI
448png_start_read_image(png_structp png_ptr)
449{
450 png_debug(1, "in png_start_read_image");
451
452 if (png_ptr == NULL)
453 return;
454 if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
455 png_read_start_row(png_ptr);
456}
457#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
458
459#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
460void PNGAPI
461png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
462{
463 PNG_IDAT;
464 PNG_CONST int png_pass_dsp_mask[7] = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55,
465 0xff};
466 PNG_CONST int png_pass_mask[7] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
467 int ret;
468
469 if (png_ptr == NULL)
470 return;
471
472 png_debug2(1, "in png_read_row (row %lu, pass %d)",
473 (unsigned long) png_ptr->row_number, png_ptr->pass);
474
475 if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
476 png_read_start_row(png_ptr);
477 if (png_ptr->row_number == 0 && png_ptr->pass == 0)
478 {
479 /* Check for transforms that have been set but were defined out */
480#if defined(PNG_WRITE_INVERT_SUPPORTED) && !defined(PNG_READ_INVERT_SUPPORTED)
481 if (png_ptr->transformations & PNG_INVERT_MONO)
482 png_warning(png_ptr, "PNG_READ_INVERT_SUPPORTED is not defined");
483#endif
484#if defined(PNG_WRITE_FILLER_SUPPORTED) && !defined(PNG_READ_FILLER_SUPPORTED)
485 if (png_ptr->transformations & PNG_FILLER)
486 png_warning(png_ptr, "PNG_READ_FILLER_SUPPORTED is not defined");
487#endif
488#if defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
489 !defined(PNG_READ_PACKSWAP_SUPPORTED)
490 if (png_ptr->transformations & PNG_PACKSWAP)
491 png_warning(png_ptr, "PNG_READ_PACKSWAP_SUPPORTED is not defined");
492#endif
493#if defined(PNG_WRITE_PACK_SUPPORTED) && !defined(PNG_READ_PACK_SUPPORTED)
494 if (png_ptr->transformations & PNG_PACK)
495 png_warning(png_ptr, "PNG_READ_PACK_SUPPORTED is not defined");
496#endif
497#if defined(PNG_WRITE_SHIFT_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED)
498 if (png_ptr->transformations & PNG_SHIFT)
499 png_warning(png_ptr, "PNG_READ_SHIFT_SUPPORTED is not defined");
500#endif
501#if defined(PNG_WRITE_BGR_SUPPORTED) && !defined(PNG_READ_BGR_SUPPORTED)
502 if (png_ptr->transformations & PNG_BGR)
503 png_warning(png_ptr, "PNG_READ_BGR_SUPPORTED is not defined");
504#endif
505#if defined(PNG_WRITE_SWAP_SUPPORTED) && !defined(PNG_READ_SWAP_SUPPORTED)
506 if (png_ptr->transformations & PNG_SWAP_BYTES)
507 png_warning(png_ptr, "PNG_READ_SWAP_SUPPORTED is not defined");
508#endif
509 }
510
511#ifdef PNG_READ_INTERLACING_SUPPORTED
512 /* If interlaced and we do not need a new row, combine row and return */
513 if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
514 {
515 switch (png_ptr->pass)
516 {
517 case 0:
518 if (png_ptr->row_number & 0x07)
519 {
520 if (dsp_row != NULL)
521 png_combine_row(png_ptr, dsp_row,
522 png_pass_dsp_mask[png_ptr->pass]);
523 png_read_finish_row(png_ptr);
524 return;
525 }
526 break;
527 case 1:
528 if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
529 {
530 if (dsp_row != NULL)
531 png_combine_row(png_ptr, dsp_row,
532 png_pass_dsp_mask[png_ptr->pass]);
533 png_read_finish_row(png_ptr);
534 return;
535 }
536 break;
537 case 2:
538 if ((png_ptr->row_number & 0x07) != 4)
539 {
540 if (dsp_row != NULL && (png_ptr->row_number & 4))
541 png_combine_row(png_ptr, dsp_row,
542 png_pass_dsp_mask[png_ptr->pass]);
543 png_read_finish_row(png_ptr);
544 return;
545 }
546 break;
547 case 3:
548 if ((png_ptr->row_number & 3) || png_ptr->width < 3)
549 {
550 if (dsp_row != NULL)
551 png_combine_row(png_ptr, dsp_row,
552 png_pass_dsp_mask[png_ptr->pass]);
553 png_read_finish_row(png_ptr);
554 return;
555 }
556 break;
557 case 4:
558 if ((png_ptr->row_number & 3) != 2)
559 {
560 if (dsp_row != NULL && (png_ptr->row_number & 2))
561 png_combine_row(png_ptr, dsp_row,
562 png_pass_dsp_mask[png_ptr->pass]);
563 png_read_finish_row(png_ptr);
564 return;
565 }
566 break;
567 case 5:
568 if ((png_ptr->row_number & 1) || png_ptr->width < 2)
569 {
570 if (dsp_row != NULL)
571 png_combine_row(png_ptr, dsp_row,
572 png_pass_dsp_mask[png_ptr->pass]);
573 png_read_finish_row(png_ptr);
574 return;
575 }
576 break;
577 case 6:
578 if (!(png_ptr->row_number & 1))
579 {
580 png_read_finish_row(png_ptr);
581 return;
582 }
583 break;
584 }
585 }
586#endif
587
588 if (!(png_ptr->mode & PNG_HAVE_IDAT))
589 png_error(png_ptr, "Invalid attempt to read row data");
590
591 png_ptr->zstream.next_out = png_ptr->row_buf;
592 png_ptr->zstream.avail_out =
593 (uInt)(PNG_ROWBYTES(png_ptr->pixel_depth,
594 png_ptr->iwidth) + 1);
595 do
596 {
597 if (!(png_ptr->zstream.avail_in))
598 {
599 while (!png_ptr->idat_size)
600 {
601 png_crc_finish(png_ptr, 0);
602
603 png_ptr->idat_size = png_read_chunk_header(png_ptr);
604 if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
605 png_error(png_ptr, "Not enough image data");
606 }
607 png_ptr->zstream.avail_in = (uInt)png_ptr->zbuf_size;
608 png_ptr->zstream.next_in = png_ptr->zbuf;
609 if (png_ptr->zbuf_size > png_ptr->idat_size)
610 png_ptr->zstream.avail_in = (uInt)png_ptr->idat_size;
611 png_crc_read(png_ptr, png_ptr->zbuf,
612 (png_size_t)png_ptr->zstream.avail_in);
613 png_ptr->idat_size -= png_ptr->zstream.avail_in;
614 }
615 ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
616 if (ret == Z_STREAM_END)
617 {
618 if (png_ptr->zstream.avail_out || png_ptr->zstream.avail_in ||
619 png_ptr->idat_size)
620 png_benign_error(png_ptr, "Extra compressed data");
621 png_ptr->mode |= PNG_AFTER_IDAT;
622 png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
623 break;
624 }
625 if (ret != Z_OK)
626 png_error(png_ptr, png_ptr->zstream.msg ? png_ptr->zstream.msg :
627 "Decompression error");
628
629 } while (png_ptr->zstream.avail_out);
630
631 png_ptr->row_info.color_type = png_ptr->color_type;
632 png_ptr->row_info.width = png_ptr->iwidth;
633 png_ptr->row_info.channels = png_ptr->channels;
634 png_ptr->row_info.bit_depth = png_ptr->bit_depth;
635 png_ptr->row_info.pixel_depth = png_ptr->pixel_depth;
636 png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
637 png_ptr->row_info.width);
638
639 if (png_ptr->row_buf[0])
640 png_read_filter_row(png_ptr, &(png_ptr->row_info),
641 png_ptr->row_buf + 1, png_ptr->prev_row + 1,
642 (int)(png_ptr->row_buf[0]));
643
644 png_memcpy(png_ptr->prev_row, png_ptr->row_buf, png_ptr->rowbytes + 1);
645
646#ifdef PNG_MNG_FEATURES_SUPPORTED
647 if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
648 (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
649 {
650 /* Intrapixel differencing */
651 png_do_read_intrapixel(&(png_ptr->row_info), png_ptr->row_buf + 1);
652 }
653#endif
654
655
656 if (png_ptr->transformations || (png_ptr->flags&PNG_FLAG_STRIP_ALPHA))
657 png_do_read_transformations(png_ptr);
658
659#ifdef PNG_READ_INTERLACING_SUPPORTED
660 /* Blow up interlaced rows to full size */
661 if (png_ptr->interlaced &&
662 (png_ptr->transformations & PNG_INTERLACE))
663 {
664 if (png_ptr->pass < 6)
665 /* Old interface (pre-1.0.9):
666 * png_do_read_interlace(&(png_ptr->row_info),
667 * png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations);
668 */
669 png_do_read_interlace(png_ptr);
670
671 if (dsp_row != NULL)
672 png_combine_row(png_ptr, dsp_row,
673 png_pass_dsp_mask[png_ptr->pass]);
674 if (row != NULL)
675 png_combine_row(png_ptr, row,
676 png_pass_mask[png_ptr->pass]);
677 }
678 else
679#endif
680 {
681 if (row != NULL)
682 png_combine_row(png_ptr, row, 0xff);
683 if (dsp_row != NULL)
684 png_combine_row(png_ptr, dsp_row, 0xff);
685 }
686 png_read_finish_row(png_ptr);
687
688 if (png_ptr->read_row_fn != NULL)
689 (*(png_ptr->read_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
690}
691#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
692
693#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
694/* Read one or more rows of image data. If the image is interlaced,
695 * and png_set_interlace_handling() has been called, the rows need to
696 * contain the contents of the rows from the previous pass. If the
697 * image has alpha or transparency, and png_handle_alpha()[*] has been
698 * called, the rows contents must be initialized to the contents of the
699 * screen.
700 *
701 * "row" holds the actual image, and pixels are placed in it
702 * as they arrive. If the image is displayed after each pass, it will
703 * appear to "sparkle" in. "display_row" can be used to display a
704 * "chunky" progressive image, with finer detail added as it becomes
705 * available. If you do not want this "chunky" display, you may pass
706 * NULL for display_row. If you do not want the sparkle display, and
707 * you have not called png_handle_alpha(), you may pass NULL for rows.
708 * If you have called png_handle_alpha(), and the image has either an
709 * alpha channel or a transparency chunk, you must provide a buffer for
710 * rows. In this case, you do not have to provide a display_row buffer
711 * also, but you may. If the image is not interlaced, or if you have
712 * not called png_set_interlace_handling(), the display_row buffer will
713 * be ignored, so pass NULL to it.
714 *
715 * [*] png_handle_alpha() does not exist yet, as of this version of libpng
716 */
717
718void PNGAPI
719png_read_rows(png_structp png_ptr, png_bytepp row,
720 png_bytepp display_row, png_uint_32 num_rows)
721{
722 png_uint_32 i;
723 png_bytepp rp;
724 png_bytepp dp;
725
726 png_debug(1, "in png_read_rows");
727
728 if (png_ptr == NULL)
729 return;
730 rp = row;
731 dp = display_row;
732 if (rp != NULL && dp != NULL)
733 for (i = 0; i < num_rows; i++)
734 {
735 png_bytep rptr = *rp++;
736 png_bytep dptr = *dp++;
737
738 png_read_row(png_ptr, rptr, dptr);
739 }
740 else if (rp != NULL)
741 for (i = 0; i < num_rows; i++)
742 {
743 png_bytep rptr = *rp;
744 png_read_row(png_ptr, rptr, NULL);
745 rp++;
746 }
747 else if (dp != NULL)
748 for (i = 0; i < num_rows; i++)
749 {
750 png_bytep dptr = *dp;
751 png_read_row(png_ptr, NULL, dptr);
752 dp++;
753 }
754}
755#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
756
757#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
758/* Read the entire image. If the image has an alpha channel or a tRNS
759 * chunk, and you have called png_handle_alpha()[*], you will need to
760 * initialize the image to the current image that PNG will be overlaying.
761 * We set the num_rows again here, in case it was incorrectly set in
762 * png_read_start_row() by a call to png_read_update_info() or
763 * png_start_read_image() if png_set_interlace_handling() wasn't called
764 * prior to either of these functions like it should have been. You can
765 * only call this function once. If you desire to have an image for
766 * each pass of a interlaced image, use png_read_rows() instead.
767 *
768 * [*] png_handle_alpha() does not exist yet, as of this version of libpng
769 */
770void PNGAPI
771png_read_image(png_structp png_ptr, png_bytepp image)
772{
773 png_uint_32 i, image_height;
774 int pass, j;
775 png_bytepp rp;
776
777 png_debug(1, "in png_read_image");
778
779 if (png_ptr == NULL)
780 return;
781
782#ifdef PNG_READ_INTERLACING_SUPPORTED
783 pass = png_set_interlace_handling(png_ptr);
784#else
785 if (png_ptr->interlaced)
786 png_error(png_ptr,
787 "Cannot read interlaced image -- interlace handler disabled");
788 pass = 1;
789#endif
790
791
792 image_height=png_ptr->height;
793 png_ptr->num_rows = image_height; /* Make sure this is set correctly */
794
795 for (j = 0; j < pass; j++)
796 {
797 rp = image;
798 for (i = 0; i < image_height; i++)
799 {
800 png_read_row(png_ptr, *rp, NULL);
801 rp++;
802 }
803 }
804}
805#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
806
807#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
808/* Read the end of the PNG file. Will not read past the end of the
809 * file, will verify the end is accurate, and will read any comments
810 * or time information at the end of the file, if info is not NULL.
811 */
812void PNGAPI
813png_read_end(png_structp png_ptr, png_infop info_ptr)
814{
815 png_debug(1, "in png_read_end");
816
817 if (png_ptr == NULL)
818 return;
819 png_crc_finish(png_ptr, 0); /* Finish off CRC from last IDAT chunk */
820
821 do
822 {
823 PNG_IHDR;
824 PNG_IDAT;
825 PNG_IEND;
826 PNG_PLTE;
827#ifdef PNG_READ_bKGD_SUPPORTED
828 PNG_bKGD;
829#endif
830#ifdef PNG_READ_cHRM_SUPPORTED
831 PNG_cHRM;
832#endif
833#ifdef PNG_READ_gAMA_SUPPORTED
834 PNG_gAMA;
835#endif
836#ifdef PNG_READ_hIST_SUPPORTED
837 PNG_hIST;
838#endif
839#ifdef PNG_READ_iCCP_SUPPORTED
840 PNG_iCCP;
841#endif
842#ifdef PNG_READ_iTXt_SUPPORTED
843 PNG_iTXt;
844#endif
845#ifdef PNG_READ_oFFs_SUPPORTED
846 PNG_oFFs;
847#endif
848#ifdef PNG_READ_pCAL_SUPPORTED
849 PNG_pCAL;
850#endif
851#ifdef PNG_READ_pHYs_SUPPORTED
852 PNG_pHYs;
853#endif
854#ifdef PNG_READ_sBIT_SUPPORTED
855 PNG_sBIT;
856#endif
857#ifdef PNG_READ_sCAL_SUPPORTED
858 PNG_sCAL;
859#endif
860#ifdef PNG_READ_sPLT_SUPPORTED
861 PNG_sPLT;
862#endif
863#ifdef PNG_READ_sRGB_SUPPORTED
864 PNG_sRGB;
865#endif
866#ifdef PNG_READ_tEXt_SUPPORTED
867 PNG_tEXt;
868#endif
869#ifdef PNG_READ_tIME_SUPPORTED
870 PNG_tIME;
871#endif
872#ifdef PNG_READ_tRNS_SUPPORTED
873 PNG_tRNS;
874#endif
875#ifdef PNG_READ_zTXt_SUPPORTED
876 PNG_zTXt;
877#endif
878 png_uint_32 length = png_read_chunk_header(png_ptr);
879 PNG_CONST png_bytep chunk_name = png_ptr->chunk_name;
880
881 if (!png_memcmp(chunk_name, png_IHDR, 4))
882 png_handle_IHDR(png_ptr, info_ptr, length);
883 else if (!png_memcmp(chunk_name, png_IEND, 4))
884 png_handle_IEND(png_ptr, info_ptr, length);
885#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
886 else if (png_handle_as_unknown(png_ptr, chunk_name))
887 {
888 if (!png_memcmp(chunk_name, png_IDAT, 4))
889 {
890 if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
891 png_benign_error(png_ptr, "Too many IDATs found");
892 }
893 png_handle_unknown(png_ptr, info_ptr, length);
894 if (!png_memcmp(chunk_name, png_PLTE, 4))
895 png_ptr->mode |= PNG_HAVE_PLTE;
896 }
897#endif
898 else if (!png_memcmp(chunk_name, png_IDAT, 4))
899 {
900 /* Zero length IDATs are legal after the last IDAT has been
901 * read, but not after other chunks have been read.
902 */
903 if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
904 png_benign_error(png_ptr, "Too many IDATs found");
905 png_crc_finish(png_ptr, length);
906 }
907 else if (!png_memcmp(chunk_name, png_PLTE, 4))
908 png_handle_PLTE(png_ptr, info_ptr, length);
909#ifdef PNG_READ_bKGD_SUPPORTED
910 else if (!png_memcmp(chunk_name, png_bKGD, 4))
911 png_handle_bKGD(png_ptr, info_ptr, length);
912#endif
913#ifdef PNG_READ_cHRM_SUPPORTED
914 else if (!png_memcmp(chunk_name, png_cHRM, 4))
915 png_handle_cHRM(png_ptr, info_ptr, length);
916#endif
917#ifdef PNG_READ_gAMA_SUPPORTED
918 else if (!png_memcmp(chunk_name, png_gAMA, 4))
919 png_handle_gAMA(png_ptr, info_ptr, length);
920#endif
921#ifdef PNG_READ_hIST_SUPPORTED
922 else if (!png_memcmp(chunk_name, png_hIST, 4))
923 png_handle_hIST(png_ptr, info_ptr, length);
924#endif
925#ifdef PNG_READ_oFFs_SUPPORTED
926 else if (!png_memcmp(chunk_name, png_oFFs, 4))
927 png_handle_oFFs(png_ptr, info_ptr, length);
928#endif
929#ifdef PNG_READ_pCAL_SUPPORTED
930 else if (!png_memcmp(chunk_name, png_pCAL, 4))
931 png_handle_pCAL(png_ptr, info_ptr, length);
932#endif
933#ifdef PNG_READ_sCAL_SUPPORTED
934 else if (!png_memcmp(chunk_name, png_sCAL, 4))
935 png_handle_sCAL(png_ptr, info_ptr, length);
936#endif
937#ifdef PNG_READ_pHYs_SUPPORTED
938 else if (!png_memcmp(chunk_name, png_pHYs, 4))
939 png_handle_pHYs(png_ptr, info_ptr, length);
940#endif
941#ifdef PNG_READ_sBIT_SUPPORTED
942 else if (!png_memcmp(chunk_name, png_sBIT, 4))
943 png_handle_sBIT(png_ptr, info_ptr, length);
944#endif
945#ifdef PNG_READ_sRGB_SUPPORTED
946 else if (!png_memcmp(chunk_name, png_sRGB, 4))
947 png_handle_sRGB(png_ptr, info_ptr, length);
948#endif
949#ifdef PNG_READ_iCCP_SUPPORTED
950 else if (!png_memcmp(chunk_name, png_iCCP, 4))
951 png_handle_iCCP(png_ptr, info_ptr, length);
952#endif
953#ifdef PNG_READ_sPLT_SUPPORTED
954 else if (!png_memcmp(chunk_name, png_sPLT, 4))
955 png_handle_sPLT(png_ptr, info_ptr, length);
956#endif
957#ifdef PNG_READ_tEXt_SUPPORTED
958 else if (!png_memcmp(chunk_name, png_tEXt, 4))
959 png_handle_tEXt(png_ptr, info_ptr, length);
960#endif
961#ifdef PNG_READ_tIME_SUPPORTED
962 else if (!png_memcmp(chunk_name, png_tIME, 4))
963 png_handle_tIME(png_ptr, info_ptr, length);
964#endif
965#ifdef PNG_READ_tRNS_SUPPORTED
966 else if (!png_memcmp(chunk_name, png_tRNS, 4))
967 png_handle_tRNS(png_ptr, info_ptr, length);
968#endif
969#ifdef PNG_READ_zTXt_SUPPORTED
970 else if (!png_memcmp(chunk_name, png_zTXt, 4))
971 png_handle_zTXt(png_ptr, info_ptr, length);
972#endif
973#ifdef PNG_READ_iTXt_SUPPORTED
974 else if (!png_memcmp(chunk_name, png_iTXt, 4))
975 png_handle_iTXt(png_ptr, info_ptr, length);
976#endif
977 else
978 png_handle_unknown(png_ptr, info_ptr, length);
979 } while (!(png_ptr->mode & PNG_HAVE_IEND));
980}
981#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
982
983/* Free all memory used by the read */
984void PNGAPI
985png_destroy_read_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr,
986 png_infopp end_info_ptr_ptr)
987{
988 png_structp png_ptr = NULL;
989 png_infop info_ptr = NULL, end_info_ptr = NULL;
990#ifdef PNG_USER_MEM_SUPPORTED
991 png_free_ptr free_fn = NULL;
992 png_voidp mem_ptr = NULL;
993#endif
994
995 png_debug(1, "in png_destroy_read_struct");
996
997 if (png_ptr_ptr != NULL)
998 png_ptr = *png_ptr_ptr;
999 if (png_ptr == NULL)
1000 return;
1001
1002#ifdef PNG_USER_MEM_SUPPORTED
1003 free_fn = png_ptr->free_fn;
1004 mem_ptr = png_ptr->mem_ptr;
1005#endif
1006
1007 if (info_ptr_ptr != NULL)
1008 info_ptr = *info_ptr_ptr;
1009
1010 if (end_info_ptr_ptr != NULL)
1011 end_info_ptr = *end_info_ptr_ptr;
1012
1013 png_read_destroy(png_ptr, info_ptr, end_info_ptr);
1014
1015 if (info_ptr != NULL)
1016 {
1017#ifdef PNG_TEXT_SUPPORTED
1018 png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, -1);
1019#endif
1020
1021#ifdef PNG_USER_MEM_SUPPORTED
1022 png_destroy_struct_2((png_voidp)info_ptr, (png_free_ptr)free_fn,
1023 (png_voidp)mem_ptr);
1024#else
1025 png_destroy_struct((png_voidp)info_ptr);
1026#endif
1027 *info_ptr_ptr = NULL;
1028 }
1029
1030 if (end_info_ptr != NULL)
1031 {
1032#ifdef PNG_READ_TEXT_SUPPORTED
1033 png_free_data(png_ptr, end_info_ptr, PNG_FREE_TEXT, -1);
1034#endif
1035#ifdef PNG_USER_MEM_SUPPORTED
1036 png_destroy_struct_2((png_voidp)end_info_ptr, (png_free_ptr)free_fn,
1037 (png_voidp)mem_ptr);
1038#else
1039 png_destroy_struct((png_voidp)end_info_ptr);
1040#endif
1041 *end_info_ptr_ptr = NULL;
1042 }
1043
1044 if (png_ptr != NULL)
1045 {
1046#ifdef PNG_USER_MEM_SUPPORTED
1047 png_destroy_struct_2((png_voidp)png_ptr, (png_free_ptr)free_fn,
1048 (png_voidp)mem_ptr);
1049#else
1050 png_destroy_struct((png_voidp)png_ptr);
1051#endif
1052 *png_ptr_ptr = NULL;
1053 }
1054}
1055
1056/* Free all memory used by the read (old method) */
1057void /* PRIVATE */
1058png_read_destroy(png_structp png_ptr, png_infop info_ptr,
1059 png_infop end_info_ptr)
1060{
1061#ifdef PNG_SETJMP_SUPPORTED
1062 jmp_buf tmp_jmp;
1063#endif
1064 png_error_ptr error_fn;
1065 png_error_ptr warning_fn;
1066 png_voidp error_ptr;
1067#ifdef PNG_USER_MEM_SUPPORTED
1068 png_free_ptr free_fn;
1069#endif
1070
1071 png_debug(1, "in png_read_destroy");
1072
1073 if (info_ptr != NULL)
1074 png_info_destroy(png_ptr, info_ptr);
1075
1076 if (end_info_ptr != NULL)
1077 png_info_destroy(png_ptr, end_info_ptr);
1078
1079 png_free(png_ptr, png_ptr->zbuf);
1080 png_free(png_ptr, png_ptr->big_row_buf);
1081 png_free(png_ptr, png_ptr->prev_row);
1082 png_free(png_ptr, png_ptr->chunkdata);
1083#ifdef PNG_READ_QUANTIZE_SUPPORTED
1084 png_free(png_ptr, png_ptr->palette_lookup);
1085 png_free(png_ptr, png_ptr->quantize_index);
1086#endif
1087#ifdef PNG_READ_GAMMA_SUPPORTED
1088 png_free(png_ptr, png_ptr->gamma_table);
1089#endif
1090#ifdef PNG_READ_BACKGROUND_SUPPORTED
1091 png_free(png_ptr, png_ptr->gamma_from_1);
1092 png_free(png_ptr, png_ptr->gamma_to_1);
1093#endif
1094 if (png_ptr->free_me & PNG_FREE_PLTE)
1095 png_zfree(png_ptr, png_ptr->palette);
1096 png_ptr->free_me &= ~PNG_FREE_PLTE;
1097#if defined(PNG_tRNS_SUPPORTED) || \
1098 defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
1099 if (png_ptr->free_me & PNG_FREE_TRNS)
1100 png_free(png_ptr, png_ptr->trans_alpha);
1101 png_ptr->free_me &= ~PNG_FREE_TRNS;
1102#endif
1103#ifdef PNG_READ_hIST_SUPPORTED
1104 if (png_ptr->free_me & PNG_FREE_HIST)
1105 png_free(png_ptr, png_ptr->hist);
1106 png_ptr->free_me &= ~PNG_FREE_HIST;
1107#endif
1108#ifdef PNG_READ_GAMMA_SUPPORTED
1109 if (png_ptr->gamma_16_table != NULL)
1110 {
1111 int i;
1112 int istop = (1 << (8 - png_ptr->gamma_shift));
1113 for (i = 0; i < istop; i++)
1114 {
1115 png_free(png_ptr, png_ptr->gamma_16_table[i]);
1116 }
1117 png_free(png_ptr, png_ptr->gamma_16_table);
1118 }
1119#ifdef PNG_READ_BACKGROUND_SUPPORTED
1120 if (png_ptr->gamma_16_from_1 != NULL)
1121 {
1122 int i;
1123 int istop = (1 << (8 - png_ptr->gamma_shift));
1124 for (i = 0; i < istop; i++)
1125 {
1126 png_free(png_ptr, png_ptr->gamma_16_from_1[i]);
1127 }
1128 png_free(png_ptr, png_ptr->gamma_16_from_1);
1129 }
1130 if (png_ptr->gamma_16_to_1 != NULL)
1131 {
1132 int i;
1133 int istop = (1 << (8 - png_ptr->gamma_shift));
1134 for (i = 0; i < istop; i++)
1135 {
1136 png_free(png_ptr, png_ptr->gamma_16_to_1[i]);
1137 }
1138 png_free(png_ptr, png_ptr->gamma_16_to_1);
1139 }
1140#endif
1141#endif
1142#ifdef PNG_TIME_RFC1123_SUPPORTED
1143 png_free(png_ptr, png_ptr->time_buffer);
1144#endif
1145
1146 inflateEnd(&png_ptr->zstream);
1147#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1148 png_free(png_ptr, png_ptr->save_buffer);
1149#endif
1150
1151#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1152#ifdef PNG_TEXT_SUPPORTED
1153 png_free(png_ptr, png_ptr->current_text);
1154#endif /* PNG_TEXT_SUPPORTED */
1155#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
1156
1157 /* Save the important info out of the png_struct, in case it is
1158 * being used again.
1159 */
1160#ifdef PNG_SETJMP_SUPPORTED
1161 png_memcpy(tmp_jmp, png_ptr->jmpbuf, png_sizeof(jmp_buf));
1162#endif
1163
1164 error_fn = png_ptr->error_fn;
1165 warning_fn = png_ptr->warning_fn;
1166 error_ptr = png_ptr->error_ptr;
1167#ifdef PNG_USER_MEM_SUPPORTED
1168 free_fn = png_ptr->free_fn;
1169#endif
1170
1171 png_memset(png_ptr, 0, png_sizeof(png_struct));
1172
1173 png_ptr->error_fn = error_fn;
1174 png_ptr->warning_fn = warning_fn;
1175 png_ptr->error_ptr = error_ptr;
1176#ifdef PNG_USER_MEM_SUPPORTED
1177 png_ptr->free_fn = free_fn;
1178#endif
1179
1180#ifdef PNG_SETJMP_SUPPORTED
1181 png_memcpy(png_ptr->jmpbuf, tmp_jmp, png_sizeof(jmp_buf));
1182#endif
1183
1184}
1185
1186void PNGAPI
1187png_set_read_status_fn(png_structp png_ptr, png_read_status_ptr read_row_fn)
1188{
1189 if (png_ptr == NULL)
1190 return;
1191 png_ptr->read_row_fn = read_row_fn;
1192}
1193
1194
1195#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1196#ifdef PNG_INFO_IMAGE_SUPPORTED
1197void PNGAPI
1198png_read_png(png_structp png_ptr, png_infop info_ptr,
1199 int transforms,
1200 voidp params)
1201{
1202 int row;
1203
1204 if (png_ptr == NULL)
1205 return;
1206
1207 /* png_read_info() gives us all of the information from the
1208 * PNG file before the first IDAT (image data chunk).
1209 */
1210 png_read_info(png_ptr, info_ptr);
1211 if (info_ptr->height > PNG_UINT_32_MAX/png_sizeof(png_bytep))
1212 png_error(png_ptr, "Image is too high to process with png_read_png()");
1213
1214 /* -------------- image transformations start here ------------------- */
1215
1216#ifdef PNG_READ_16_TO_8_SUPPORTED
1217 /* Tell libpng to strip 16 bit/color files down to 8 bits per color.
1218 */
1219 if (transforms & PNG_TRANSFORM_STRIP_16)
1220 png_set_strip_16(png_ptr);
1221#endif
1222
1223#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
1224 /* Strip alpha bytes from the input data without combining with
1225 * the background (not recommended).
1226 */
1227 if (transforms & PNG_TRANSFORM_STRIP_ALPHA)
1228 png_set_strip_alpha(png_ptr);
1229#endif
1230
1231#if defined(PNG_READ_PACK_SUPPORTED) && !defined(PNG_READ_EXPAND_SUPPORTED)
1232 /* Extract multiple pixels with bit depths of 1, 2, or 4 from a single
1233 * byte into separate bytes (useful for paletted and grayscale images).
1234 */
1235 if (transforms & PNG_TRANSFORM_PACKING)
1236 png_set_packing(png_ptr);
1237#endif
1238
1239#ifdef PNG_READ_PACKSWAP_SUPPORTED
1240 /* Change the order of packed pixels to least significant bit first
1241 * (not useful if you are using png_set_packing).
1242 */
1243 if (transforms & PNG_TRANSFORM_PACKSWAP)
1244 png_set_packswap(png_ptr);
1245#endif
1246
1247#ifdef PNG_READ_EXPAND_SUPPORTED
1248 /* Expand paletted colors into true RGB triplets
1249 * Expand grayscale images to full 8 bits from 1, 2, or 4 bits/pixel
1250 * Expand paletted or RGB images with transparency to full alpha
1251 * channels so the data will be available as RGBA quartets.
1252 */
1253 if (transforms & PNG_TRANSFORM_EXPAND)
1254 if ((png_ptr->bit_depth < 8) ||
1255 (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ||
1256 (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)))
1257 png_set_expand(png_ptr);
1258#endif
1259
1260 /* We don't handle background color or gamma transformation or quantizing.
1261 */
1262
1263#ifdef PNG_READ_INVERT_SUPPORTED
1264 /* Invert monochrome files to have 0 as white and 1 as black
1265 */
1266 if (transforms & PNG_TRANSFORM_INVERT_MONO)
1267 png_set_invert_mono(png_ptr);
1268#endif
1269
1270#ifdef PNG_READ_SHIFT_SUPPORTED
1271 /* If you want to shift the pixel values from the range [0,255] or
1272 * [0,65535] to the original [0,7] or [0,31], or whatever range the
1273 * colors were originally in:
1274 */
1275 if ((transforms & PNG_TRANSFORM_SHIFT)
1276 && png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT))
1277 {
1278 png_color_8p sig_bit;
1279
1280 png_get_sBIT(png_ptr, info_ptr, &sig_bit);
1281 png_set_shift(png_ptr, sig_bit);
1282 }
1283#endif
1284
1285#ifdef PNG_READ_BGR_SUPPORTED
1286 /* Flip the RGB pixels to BGR (or RGBA to BGRA)
1287 */
1288 if (transforms & PNG_TRANSFORM_BGR)
1289 png_set_bgr(png_ptr);
1290#endif
1291
1292#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
1293 /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR)
1294 */
1295 if (transforms & PNG_TRANSFORM_SWAP_ALPHA)
1296 png_set_swap_alpha(png_ptr);
1297#endif
1298
1299#ifdef PNG_READ_SWAP_SUPPORTED
1300 /* Swap bytes of 16 bit files to least significant byte first
1301 */
1302 if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
1303 png_set_swap(png_ptr);
1304#endif
1305
1306/* Added at libpng-1.2.41 */
1307#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
1308 /* Invert the alpha channel from opacity to transparency
1309 */
1310 if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
1311 png_set_invert_alpha(png_ptr);
1312#endif
1313
1314/* Added at libpng-1.2.41 */
1315#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
1316 /* Expand grayscale image to RGB
1317 */
1318 if (transforms & PNG_TRANSFORM_GRAY_TO_RGB)
1319 png_set_gray_to_rgb(png_ptr);
1320#endif
1321
1322 /* We don't handle adding filler bytes */
1323
1324 /* Optional call to gamma correct and add the background to the palette
1325 * and update info structure. REQUIRED if you are expecting libpng to
1326 * update the palette for you (i.e., you selected such a transform above).
1327 */
1328 png_read_update_info(png_ptr, info_ptr);
1329
1330 /* -------------- image transformations end here ------------------- */
1331
1332 png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
1333 if (info_ptr->row_pointers == NULL)
1334 {
1335 png_uint_32 iptr;
1336
1337 info_ptr->row_pointers = (png_bytepp)png_malloc(png_ptr,
1338 info_ptr->height * png_sizeof(png_bytep));
1339 for (iptr=0; iptr<info_ptr->height; iptr++)
1340 info_ptr->row_pointers[iptr] = NULL;
1341
1342 info_ptr->free_me |= PNG_FREE_ROWS;
1343
1344 for (row = 0; row < (int)info_ptr->height; row++)
1345 info_ptr->row_pointers[row] = (png_bytep)png_malloc(png_ptr,
1346 png_get_rowbytes(png_ptr, info_ptr));
1347 }
1348
1349 png_read_image(png_ptr, info_ptr->row_pointers);
1350 info_ptr->valid |= PNG_INFO_IDAT;
1351
1352 /* Read rest of file, and get additional chunks in info_ptr - REQUIRED */
1353 png_read_end(png_ptr, info_ptr);
1354
1355 transforms = transforms; /* Quiet compiler warnings */
1356 params = params;
1357
1358}
1359#endif /* PNG_INFO_IMAGE_SUPPORTED */
1360#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
1361#endif /* PNG_READ_SUPPORTED */
wxWidgets (Impactor)