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source: bootcd/isolinux/syslinux-6.03/com32/lib/libpng/png.c @ e16e8f2

Last change on this file since e16e8f2 was e16e8f2, checked in by Edwin Eefting <edwin@datux.nl>, 3 years ago
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1
2	/* png.c - location for general purpose libpng functions
3	*
4	* Last changed in libpng 1.2.43 [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
14	#define PNG_INTERNAL
15	#define PNG_NO_EXTERN
16	#define PNG_NO_PEDANTIC_WARNINGS
17	#include "png.h"
18
19	/* Generate a compiler error if there is an old png.h in the search path. */
20	typedef version_1_2_44 Your_png_h_is_not_version_1_2_44;
21
22	/* Version information for C files. This had better match the version
23	* string defined in png.h.
24	*/
25
26	#ifdef PNG_USE_GLOBAL_ARRAYS
27	/* png_libpng_ver was changed to a function in version 1.0.5c */
28	PNG_CONST char png_libpng_ver[18] = PNG_LIBPNG_VER_STRING;
29
30	#ifdef PNG_READ_SUPPORTED
31
32	/* png_sig was changed to a function in version 1.0.5c */
33	/* Place to hold the signature string for a PNG file. */
34	PNG_CONST png_byte FARDATA png_sig[8] = {137, 80, 78, 71, 13, 10, 26, 10};
35	#endif /* PNG_READ_SUPPORTED */
36
37	/* Invoke global declarations for constant strings for known chunk types */
38	PNG_IHDR;
39	PNG_IDAT;
40	PNG_IEND;
41	PNG_PLTE;
42	PNG_bKGD;
43	PNG_cHRM;
44	PNG_gAMA;
45	PNG_hIST;
46	PNG_iCCP;
47	PNG_iTXt;
48	PNG_oFFs;
49	PNG_pCAL;
50	PNG_sCAL;
51	PNG_pHYs;
52	PNG_sBIT;
53	PNG_sPLT;
54	PNG_sRGB;
55	PNG_tEXt;
56	PNG_tIME;
57	PNG_tRNS;
58	PNG_zTXt;
59
60	#ifdef PNG_READ_SUPPORTED
61	/* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
62
63	/* Start of interlace block */
64	PNG_CONST int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
65
66	/* Offset to next interlace block */
67	PNG_CONST int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
68
69	/* Start of interlace block in the y direction */
70	PNG_CONST int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
71
72	/* Offset to next interlace block in the y direction */
73	PNG_CONST int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
74
75	/* Height of interlace block. This is not currently used - if you need
76	* it, uncomment it here and in png.h
77	PNG_CONST int FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
78	*/
79
80	/* Mask to determine which pixels are valid in a pass */
81	PNG_CONST int FARDATA png_pass_mask[] =
82	{0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
83
84	/* Mask to determine which pixels to overwrite while displaying */
85	PNG_CONST int FARDATA png_pass_dsp_mask[]
86	= {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
87
88	#endif /* PNG_READ_SUPPORTED */
89	#endif /* PNG_USE_GLOBAL_ARRAYS */
90
91	/* Tells libpng that we have already handled the first "num_bytes" bytes
92	* of the PNG file signature. If the PNG data is embedded into another
93	* stream we can set num_bytes = 8 so that libpng will not attempt to read
94	* or write any of the magic bytes before it starts on the IHDR.
95	*/
96
97	#ifdef PNG_READ_SUPPORTED
98	void PNGAPI
99	png_set_sig_bytes(png_structp png_ptr, int num_bytes)
100	{
101	png_debug(1, "in png_set_sig_bytes");
102
103	if (png_ptr == NULL)
104	return;
105
106	if (num_bytes > 8)
107	png_error(png_ptr, "Too many bytes for PNG signature.");
108
109	png_ptr->sig_bytes = (png_byte)(num_bytes < 0 ? 0 : num_bytes);
110	}
111
112	/* Checks whether the supplied bytes match the PNG signature. We allow
113	* checking less than the full 8-byte signature so that those apps that
114	* already read the first few bytes of a file to determine the file type
115	* can simply check the remaining bytes for extra assurance. Returns
116	* an integer less than, equal to, or greater than zero if sig is found,
117	* respectively, to be less than, to match, or be greater than the correct
118	* PNG signature (this is the same behaviour as strcmp, memcmp, etc).
119	*/
120	int PNGAPI
121	png_sig_cmp(png_bytep sig, png_size_t start, png_size_t num_to_check)
122	{
123	png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
124	if (num_to_check > 8)
125	num_to_check = 8;
126	else if (num_to_check < 1)
127	return (-1);
128
129	if (start > 7)
130	return (-1);
131
132	if (start + num_to_check > 8)
133	num_to_check = 8 - start;
134
135	return ((int)(png_memcmp(&sig[start], &png_signature[start], num_to_check)));
136	}
137
138	#if defined(PNG_1_0_X) \|\| defined(PNG_1_2_X)
139	/* (Obsolete) function to check signature bytes. It does not allow one
140	* to check a partial signature. This function might be removed in the
141	* future - use png_sig_cmp(). Returns true (nonzero) if the file is PNG.
142	*/
143	int PNGAPI
144	png_check_sig(png_bytep sig, int num)
145	{
146	return ((int)!png_sig_cmp(sig, (png_size_t)0, (png_size_t)num));
147	}
148	#endif
149	#endif /* PNG_READ_SUPPORTED */
150
151	#if defined(PNG_READ_SUPPORTED) \|\| defined(PNG_WRITE_SUPPORTED)
152	/* Function to allocate memory for zlib and clear it to 0. */
153	#ifdef PNG_1_0_X
154	voidpf PNGAPI
155	#else
156	voidpf /* PRIVATE */
157	#endif
158	png_zalloc(voidpf png_ptr, uInt items, uInt size)
159	{
160	png_voidp ptr;
161	png_structp p=(png_structp)png_ptr;
162	png_uint_32 save_flags=p->flags;
163	png_uint_32 num_bytes;
164
165	if (png_ptr == NULL)
166	return (NULL);
167	if (items > PNG_UINT_32_MAX/size)
168	{
169	png_warning (p, "Potential overflow in png_zalloc()");
170	return (NULL);
171	}
172	num_bytes = (png_uint_32)items * size;
173
174	p->flags\|=PNG_FLAG_MALLOC_NULL_MEM_OK;
175	ptr = (png_voidp)png_malloc((png_structp)png_ptr, num_bytes);
176	p->flags=save_flags;
177
178	#if defined(PNG_1_0_X) && !defined(PNG_NO_ZALLOC_ZERO)
179	if (ptr == NULL)
180	return ((voidpf)ptr);
181
182	if (num_bytes > (png_uint_32)0x8000L)
183	{
184	png_memset(ptr, 0, (png_size_t)0x8000L);
185	png_memset((png_bytep)ptr + (png_size_t)0x8000L, 0,
186	(png_size_t)(num_bytes - (png_uint_32)0x8000L));
187	}
188	else
189	{
190	png_memset(ptr, 0, (png_size_t)num_bytes);
191	}
192	#endif
193	return ((voidpf)ptr);
194	}
195
196	/* Function to free memory for zlib */
197	#ifdef PNG_1_0_X
198	void PNGAPI
199	#else
200	void /* PRIVATE */
201	#endif
202	png_zfree(voidpf png_ptr, voidpf ptr)
203	{
204	png_free((png_structp)png_ptr, (png_voidp)ptr);
205	}
206
207	/* Reset the CRC variable to 32 bits of 1's. Care must be taken
208	* in case CRC is > 32 bits to leave the top bits 0.
209	*/
210	void /* PRIVATE */
211	png_reset_crc(png_structp png_ptr)
212	{
213	png_ptr->crc = crc32(0, Z_NULL, 0);
214	}
215
216	/* Calculate the CRC over a section of data. We can only pass as
217	* much data to this routine as the largest single buffer size. We
218	* also check that this data will actually be used before going to the
219	* trouble of calculating it.
220	*/
221	void /* PRIVATE */
222	png_calculate_crc(png_structp png_ptr, png_bytep ptr, png_size_t length)
223	{
224	int need_crc = 1;
225
226	if (png_ptr->chunk_name[0] & 0x20) /* ancillary */
227	{
228	if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
229	(PNG_FLAG_CRC_ANCILLARY_USE \| PNG_FLAG_CRC_ANCILLARY_NOWARN))
230	need_crc = 0;
231	}
232	else /* critical */
233	{
234	if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE)
235	need_crc = 0;
236	}
237
238	if (need_crc)
239	png_ptr->crc = crc32(png_ptr->crc, ptr, (uInt)length);
240	}
241
242	/* Allocate the memory for an info_struct for the application. We don't
243	* really need the png_ptr, but it could potentially be useful in the
244	* future. This should be used in favour of malloc(png_sizeof(png_info))
245	* and png_info_init() so that applications that want to use a shared
246	* libpng don't have to be recompiled if png_info changes size.
247	*/
248	png_infop PNGAPI
249	png_create_info_struct(png_structp png_ptr)
250	{
251	png_infop info_ptr;
252
253	png_debug(1, "in png_create_info_struct");
254
255	if (png_ptr == NULL)
256	return (NULL);
257
258	#ifdef PNG_USER_MEM_SUPPORTED
259	info_ptr = (png_infop)png_create_struct_2(PNG_STRUCT_INFO,
260	png_ptr->malloc_fn, png_ptr->mem_ptr);
261	#else
262	info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO);
263	#endif
264	if (info_ptr != NULL)
265	png_info_init_3(&info_ptr, png_sizeof(png_info));
266
267	return (info_ptr);
268	}
269
270	/* This function frees the memory associated with a single info struct.
271	* Normally, one would use either png_destroy_read_struct() or
272	* png_destroy_write_struct() to free an info struct, but this may be
273	* useful for some applications.
274	*/
275	void PNGAPI
276	png_destroy_info_struct(png_structp png_ptr, png_infopp info_ptr_ptr)
277	{
278	png_infop info_ptr = NULL;
279
280	png_debug(1, "in png_destroy_info_struct");
281
282	if (png_ptr == NULL)
283	return;
284
285	if (info_ptr_ptr != NULL)
286	info_ptr = *info_ptr_ptr;
287
288	if (info_ptr != NULL)
289	{
290	png_info_destroy(png_ptr, info_ptr);
291
292	#ifdef PNG_USER_MEM_SUPPORTED
293	png_destroy_struct_2((png_voidp)info_ptr, png_ptr->free_fn,
294	png_ptr->mem_ptr);
295	#else
296	png_destroy_struct((png_voidp)info_ptr);
297	#endif
298	*info_ptr_ptr = NULL;
299	}
300	}
301
302	/* Initialize the info structure. This is now an internal function (0.89)
303	* and applications using it are urged to use png_create_info_struct()
304	* instead.
305	*/
306	#if defined(PNG_1_0_X) \|\| defined(PNG_1_2_X)
307	#undef png_info_init
308	void PNGAPI
309	png_info_init(png_infop info_ptr)
310	{
311	/* We only come here via pre-1.0.12-compiled applications */
312	png_info_init_3(&info_ptr, 0);
313	}
314	#endif
315
316	void PNGAPI
317	png_info_init_3(png_infopp ptr_ptr, png_size_t png_info_struct_size)
318	{
319	png_infop info_ptr = *ptr_ptr;
320
321	png_debug(1, "in png_info_init_3");
322
323	if (info_ptr == NULL)
324	return;
325
326	if (png_sizeof(png_info) > png_info_struct_size)
327	{
328	png_destroy_struct(info_ptr);
329	info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO);
330	*ptr_ptr = info_ptr;
331	}
332
333	/* Set everything to 0 */
334	png_memset(info_ptr, 0, png_sizeof(png_info));
335	}
336
337	#ifdef PNG_FREE_ME_SUPPORTED
338	void PNGAPI
339	png_data_freer(png_structp png_ptr, png_infop info_ptr,
340	int freer, png_uint_32 mask)
341	{
342	png_debug(1, "in png_data_freer");
343
344	if (png_ptr == NULL \|\| info_ptr == NULL)
345	return;
346
347	if (freer == PNG_DESTROY_WILL_FREE_DATA)
348	info_ptr->free_me \|= mask;
349	else if (freer == PNG_USER_WILL_FREE_DATA)
350	info_ptr->free_me &= ~mask;
351	else
352	png_warning(png_ptr,
353	"Unknown freer parameter in png_data_freer.");
354	}
355	#endif
356
357	void PNGAPI
358	png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask,
359	int num)
360	{
361	png_debug(1, "in png_free_data");
362
363	if (png_ptr == NULL \|\| info_ptr == NULL)
364	return;
365
366	#ifdef PNG_TEXT_SUPPORTED
367	/* Free text item num or (if num == -1) all text items */
368	#ifdef PNG_FREE_ME_SUPPORTED
369	if ((mask & PNG_FREE_TEXT) & info_ptr->free_me)
370	#else
371	if (mask & PNG_FREE_TEXT)
372	#endif
373	{
374	if (num != -1)
375	{
376	if (info_ptr->text && info_ptr->text[num].key)
377	{
378	png_free(png_ptr, info_ptr->text[num].key);
379	info_ptr->text[num].key = NULL;
380	}
381	}
382	else
383	{
384	int i;
385	for (i = 0; i < info_ptr->num_text; i++)
386	png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, i);
387	png_free(png_ptr, info_ptr->text);
388	info_ptr->text = NULL;
389	info_ptr->num_text=0;
390	}
391	}
392	#endif
393
394	#ifdef PNG_tRNS_SUPPORTED
395	/* Free any tRNS entry */
396	#ifdef PNG_FREE_ME_SUPPORTED
397	if ((mask & PNG_FREE_TRNS) & info_ptr->free_me)
398	#else
399	if ((mask & PNG_FREE_TRNS) && (png_ptr->flags & PNG_FLAG_FREE_TRNS))
400	#endif
401	{
402	png_free(png_ptr, info_ptr->trans);
403	info_ptr->trans = NULL;
404	info_ptr->valid &= ~PNG_INFO_tRNS;
405	#ifndef PNG_FREE_ME_SUPPORTED
406	png_ptr->flags &= ~PNG_FLAG_FREE_TRNS;
407	#endif
408	}
409	#endif
410
411	#ifdef PNG_sCAL_SUPPORTED
412	/* Free any sCAL entry */
413	#ifdef PNG_FREE_ME_SUPPORTED
414	if ((mask & PNG_FREE_SCAL) & info_ptr->free_me)
415	#else
416	if (mask & PNG_FREE_SCAL)
417	#endif
418	{
419	#if defined(PNG_FIXED_POINT_SUPPORTED) && !defined(PNG_FLOATING_POINT_SUPPORTED)
420	png_free(png_ptr, info_ptr->scal_s_width);
421	png_free(png_ptr, info_ptr->scal_s_height);
422	info_ptr->scal_s_width = NULL;
423	info_ptr->scal_s_height = NULL;
424	#endif
425	info_ptr->valid &= ~PNG_INFO_sCAL;
426	}
427	#endif
428
429	#ifdef PNG_pCAL_SUPPORTED
430	/* Free any pCAL entry */
431	#ifdef PNG_FREE_ME_SUPPORTED
432	if ((mask & PNG_FREE_PCAL) & info_ptr->free_me)
433	#else
434	if (mask & PNG_FREE_PCAL)
435	#endif
436	{
437	png_free(png_ptr, info_ptr->pcal_purpose);
438	png_free(png_ptr, info_ptr->pcal_units);
439	info_ptr->pcal_purpose = NULL;
440	info_ptr->pcal_units = NULL;
441	if (info_ptr->pcal_params != NULL)
442	{
443	int i;
444	for (i = 0; i < (int)info_ptr->pcal_nparams; i++)
445	{
446	png_free(png_ptr, info_ptr->pcal_params[i]);
447	info_ptr->pcal_params[i] = NULL;
448	}
449	png_free(png_ptr, info_ptr->pcal_params);
450	info_ptr->pcal_params = NULL;
451	}
452	info_ptr->valid &= ~PNG_INFO_pCAL;
453	}
454	#endif
455
456	#ifdef PNG_iCCP_SUPPORTED
457	/* Free any iCCP entry */
458	#ifdef PNG_FREE_ME_SUPPORTED
459	if ((mask & PNG_FREE_ICCP) & info_ptr->free_me)
460	#else
461	if (mask & PNG_FREE_ICCP)
462	#endif
463	{
464	png_free(png_ptr, info_ptr->iccp_name);
465	png_free(png_ptr, info_ptr->iccp_profile);
466	info_ptr->iccp_name = NULL;
467	info_ptr->iccp_profile = NULL;
468	info_ptr->valid &= ~PNG_INFO_iCCP;
469	}
470	#endif
471
472	#ifdef PNG_sPLT_SUPPORTED
473	/* Free a given sPLT entry, or (if num == -1) all sPLT entries */
474	#ifdef PNG_FREE_ME_SUPPORTED
475	if ((mask & PNG_FREE_SPLT) & info_ptr->free_me)
476	#else
477	if (mask & PNG_FREE_SPLT)
478	#endif
479	{
480	if (num != -1)
481	{
482	if (info_ptr->splt_palettes)
483	{
484	png_free(png_ptr, info_ptr->splt_palettes[num].name);
485	png_free(png_ptr, info_ptr->splt_palettes[num].entries);
486	info_ptr->splt_palettes[num].name = NULL;
487	info_ptr->splt_palettes[num].entries = NULL;
488	}
489	}
490	else
491	{
492	if (info_ptr->splt_palettes_num)
493	{
494	int i;
495	for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
496	png_free_data(png_ptr, info_ptr, PNG_FREE_SPLT, i);
497
498	png_free(png_ptr, info_ptr->splt_palettes);
499	info_ptr->splt_palettes = NULL;
500	info_ptr->splt_palettes_num = 0;
501	}
502	info_ptr->valid &= ~PNG_INFO_sPLT;
503	}
504	}
505	#endif
506
507	#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
508	if (png_ptr->unknown_chunk.data)
509	{
510	png_free(png_ptr, png_ptr->unknown_chunk.data);
511	png_ptr->unknown_chunk.data = NULL;
512	}
513
514	#ifdef PNG_FREE_ME_SUPPORTED
515	if ((mask & PNG_FREE_UNKN) & info_ptr->free_me)
516	#else
517	if (mask & PNG_FREE_UNKN)
518	#endif
519	{
520	if (num != -1)
521	{
522	if (info_ptr->unknown_chunks)
523	{
524	png_free(png_ptr, info_ptr->unknown_chunks[num].data);
525	info_ptr->unknown_chunks[num].data = NULL;
526	}
527	}
528	else
529	{
530	int i;
531
532	if (info_ptr->unknown_chunks_num)
533	{
534	for (i = 0; i < (int)info_ptr->unknown_chunks_num; i++)
535	png_free_data(png_ptr, info_ptr, PNG_FREE_UNKN, i);
536
537	png_free(png_ptr, info_ptr->unknown_chunks);
538	info_ptr->unknown_chunks = NULL;
539	info_ptr->unknown_chunks_num = 0;
540	}
541	}
542	}
543	#endif
544
545	#ifdef PNG_hIST_SUPPORTED
546	/* Free any hIST entry */
547	#ifdef PNG_FREE_ME_SUPPORTED
548	if ((mask & PNG_FREE_HIST) & info_ptr->free_me)
549	#else
550	if ((mask & PNG_FREE_HIST) && (png_ptr->flags & PNG_FLAG_FREE_HIST))
551	#endif
552	{
553	png_free(png_ptr, info_ptr->hist);
554	info_ptr->hist = NULL;
555	info_ptr->valid &= ~PNG_INFO_hIST;
556	#ifndef PNG_FREE_ME_SUPPORTED
557	png_ptr->flags &= ~PNG_FLAG_FREE_HIST;
558	#endif
559	}
560	#endif
561
562	/* Free any PLTE entry that was internally allocated */
563	#ifdef PNG_FREE_ME_SUPPORTED
564	if ((mask & PNG_FREE_PLTE) & info_ptr->free_me)
565	#else
566	if ((mask & PNG_FREE_PLTE) && (png_ptr->flags & PNG_FLAG_FREE_PLTE))
567	#endif
568	{
569	png_zfree(png_ptr, info_ptr->palette);
570	info_ptr->palette = NULL;
571	info_ptr->valid &= ~PNG_INFO_PLTE;
572	#ifndef PNG_FREE_ME_SUPPORTED
573	png_ptr->flags &= ~PNG_FLAG_FREE_PLTE;
574	#endif
575	info_ptr->num_palette = 0;
576	}
577
578	#ifdef PNG_INFO_IMAGE_SUPPORTED
579	/* Free any image bits attached to the info structure */
580	#ifdef PNG_FREE_ME_SUPPORTED
581	if ((mask & PNG_FREE_ROWS) & info_ptr->free_me)
582	#else
583	if (mask & PNG_FREE_ROWS)
584	#endif
585	{
586	if (info_ptr->row_pointers)
587	{
588	int row;
589	for (row = 0; row < (int)info_ptr->height; row++)
590	{
591	png_free(png_ptr, info_ptr->row_pointers[row]);
592	info_ptr->row_pointers[row] = NULL;
593	}
594	png_free(png_ptr, info_ptr->row_pointers);
595	info_ptr->row_pointers = NULL;
596	}
597	info_ptr->valid &= ~PNG_INFO_IDAT;
598	}
599	#endif
600
601	#ifdef PNG_FREE_ME_SUPPORTED
602	if (num == -1)
603	info_ptr->free_me &= ~mask;
604	else
605	info_ptr->free_me &= ~(mask & ~PNG_FREE_MUL);
606	#endif
607	}
608
609	/* This is an internal routine to free any memory that the info struct is
610	* pointing to before re-using it or freeing the struct itself. Recall
611	* that png_free() checks for NULL pointers for us.
612	*/
613	void /* PRIVATE */
614	png_info_destroy(png_structp png_ptr, png_infop info_ptr)
615	{
616	png_debug(1, "in png_info_destroy");
617
618	png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
619
620	#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
621	if (png_ptr->num_chunk_list)
622	{
623	png_free(png_ptr, png_ptr->chunk_list);
624	png_ptr->chunk_list = NULL;
625	png_ptr->num_chunk_list = 0;
626	}
627	#endif
628
629	png_info_init_3(&info_ptr, png_sizeof(png_info));
630	}
631	#endif /* defined(PNG_READ_SUPPORTED) \|\| defined(PNG_WRITE_SUPPORTED) */
632
633	/* This function returns a pointer to the io_ptr associated with the user
634	* functions. The application should free any memory associated with this
635	* pointer before png_write_destroy() or png_read_destroy() are called.
636	*/
637	png_voidp PNGAPI
638	png_get_io_ptr(png_structp png_ptr)
639	{
640	if (png_ptr == NULL)
641	return (NULL);
642	return (png_ptr->io_ptr);
643	}
644
645	#if defined(PNG_READ_SUPPORTED) \|\| defined(PNG_WRITE_SUPPORTED)
646	#ifdef PNG_STDIO_SUPPORTED
647	/* Initialize the default input/output functions for the PNG file. If you
648	* use your own read or write routines, you can call either png_set_read_fn()
649	* or png_set_write_fn() instead of png_init_io(). If you have defined
650	* PNG_NO_STDIO, you must use a function of your own because "FILE *" isn't
651	* necessarily available.
652	*/
653	void PNGAPI
654	png_init_io(png_structp png_ptr, png_FILE_p fp)
655	{
656	png_debug(1, "in png_init_io");
657
658	if (png_ptr == NULL)
659	return;
660
661	png_ptr->io_ptr = (png_voidp)fp;
662	}
663	#endif
664
665	#ifdef PNG_TIME_RFC1123_SUPPORTED
666	/* Convert the supplied time into an RFC 1123 string suitable for use in
667	* a "Creation Time" or other text-based time string.
668	*/
669	png_charp PNGAPI
670	png_convert_to_rfc1123(png_structp png_ptr, png_timep ptime)
671	{
672	static PNG_CONST char short_months[12][4] =
673	{"Jan", "Feb", "Mar", "Apr", "May", "Jun",
674	"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
675
676	if (png_ptr == NULL)
677	return (NULL);
678	if (png_ptr->time_buffer == NULL)
679	{
680	png_ptr->time_buffer = (png_charp)png_malloc(png_ptr, (png_uint_32)(29*
681	png_sizeof(char)));
682	}
683
684	#ifdef _WIN32_WCE
685	{
686	wchar_t time_buf[29];
687	wsprintf(time_buf, TEXT("%d %S %d %02d:%02d:%02d +0000"),
688	ptime->day % 32, short_months[(ptime->month - 1) % 12],
689	ptime->year, ptime->hour % 24, ptime->minute % 60,
690	ptime->second % 61);
691	WideCharToMultiByte(CP_ACP, 0, time_buf, -1, png_ptr->time_buffer,
692	29, NULL, NULL);
693	}
694	#else
695	#ifdef USE_FAR_KEYWORD
696	{
697	char near_time_buf[29];
698	png_snprintf6(near_time_buf, 29, "%d %s %d %02d:%02d:%02d +0000",
699	ptime->day % 32, short_months[(ptime->month - 1) % 12],
700	ptime->year, ptime->hour % 24, ptime->minute % 60,
701	ptime->second % 61);
702	png_memcpy(png_ptr->time_buffer, near_time_buf,
703	29*png_sizeof(char));
704	}
705	#else
706	png_snprintf6(png_ptr->time_buffer, 29, "%d %s %d %02d:%02d:%02d +0000",
707	ptime->day % 32, short_months[(ptime->month - 1) % 12],
708	ptime->year, ptime->hour % 24, ptime->minute % 60,
709	ptime->second % 61);
710	#endif
711	#endif /* _WIN32_WCE */
712	return ((png_charp)png_ptr->time_buffer);
713	}
714	#endif /* PNG_TIME_RFC1123_SUPPORTED */
715
716	#endif /* defined(PNG_READ_SUPPORTED) \|\| defined(PNG_WRITE_SUPPORTED) */
717
718	png_charp PNGAPI
719	png_get_copyright(png_structp png_ptr)
720	{
721	png_ptr = png_ptr; /* Silence compiler warning about unused png_ptr */
722	#ifdef PNG_STRING_COPYRIGHT
723	return PNG_STRING_COPYRIGHT
724	#else
725	#ifdef __STDC__
726	return ((png_charp) PNG_STRING_NEWLINE \
727	"libpng version 1.2.44 - June 26, 2010" PNG_STRING_NEWLINE \
728	"Copyright (c) 1998-2010 Glenn Randers-Pehrson" PNG_STRING_NEWLINE \
729	"Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \
730	"Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \
731	PNG_STRING_NEWLINE);
732	#else
733	return ((png_charp) "libpng version 1.2.44 - June 26, 2010\
734	Copyright (c) 1998-2010 Glenn Randers-Pehrson\
735	Copyright (c) 1996-1997 Andreas Dilger\
736	Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.");
737	#endif
738	#endif
739	}
740
741	/* The following return the library version as a short string in the
742	* format 1.0.0 through 99.99.99zz. To get the version of *.h files
743	* used with your application, print out PNG_LIBPNG_VER_STRING, which
744	* is defined in png.h.
745	* Note: now there is no difference between png_get_libpng_ver() and
746	* png_get_header_ver(). Due to the version_nn_nn_nn typedef guard,
747	* it is guaranteed that png.c uses the correct version of png.h.
748	*/
749	png_charp PNGAPI
750	png_get_libpng_ver(png_structp png_ptr)
751	{
752	/* Version of .c files used when building libpng /
753	png_ptr = png_ptr; /* Silence compiler warning about unused png_ptr */
754	return ((png_charp) PNG_LIBPNG_VER_STRING);
755	}
756
757	png_charp PNGAPI
758	png_get_header_ver(png_structp png_ptr)
759	{
760	/* Version of .h files used when building libpng /
761	png_ptr = png_ptr; /* Silence compiler warning about unused png_ptr */
762	return ((png_charp) PNG_LIBPNG_VER_STRING);
763	}
764
765	png_charp PNGAPI
766	png_get_header_version(png_structp png_ptr)
767	{
768	/* Returns longer string containing both version and date */
769	png_ptr = png_ptr; /* Silence compiler warning about unused png_ptr */
770	#ifdef __STDC__
771	return ((png_charp) PNG_HEADER_VERSION_STRING
772	#ifndef PNG_READ_SUPPORTED
773	" (NO READ SUPPORT)"
774	#endif
775	PNG_STRING_NEWLINE);
776	#else
777	return ((png_charp) PNG_HEADER_VERSION_STRING);
778	#endif
779	}
780
781	#if defined(PNG_READ_SUPPORTED) \|\| defined(PNG_WRITE_SUPPORTED)
782	#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
783	int PNGAPI
784	png_handle_as_unknown(png_structp png_ptr, png_bytep chunk_name)
785	{
786	/* Check chunk_name and return "keep" value if it's on the list, else 0 */
787	int i;
788	png_bytep p;
789	if (png_ptr == NULL \|\| chunk_name == NULL \|\| png_ptr->num_chunk_list<=0)
790	return 0;
791	p = png_ptr->chunk_list + png_ptr->num_chunk_list*5 - 5;
792	for (i = png_ptr->num_chunk_list; i; i--, p -= 5)
793	if (!png_memcmp(chunk_name, p, 4))
794	return ((int)*(p + 4));
795	return 0;
796	}
797	#endif
798
799	/* This function, added to libpng-1.0.6g, is untested. */
800	int PNGAPI
801	png_reset_zstream(png_structp png_ptr)
802	{
803	if (png_ptr == NULL)
804	return Z_STREAM_ERROR;
805	return (inflateReset(&png_ptr->zstream));
806	}
807	#endif /* defined(PNG_READ_SUPPORTED) \|\| defined(PNG_WRITE_SUPPORTED) */
808
809	/* This function was added to libpng-1.0.7 */
810	png_uint_32 PNGAPI
811	png_access_version_number(void)
812	{
813	/* Version of .c files used when building libpng /
814	return((png_uint_32) PNG_LIBPNG_VER);
815	}
816
817
818	#if defined(PNG_READ_SUPPORTED) && defined(PNG_ASSEMBLER_CODE_SUPPORTED)
819	#ifndef PNG_1_0_X
820	/* This function was added to libpng 1.2.0 */
821	int PNGAPI
822	png_mmx_support(void)
823	{
824	/* Obsolete, to be removed from libpng-1.4.0 */
825	return -1;
826	}
827	#endif /* PNG_1_0_X */
828	#endif /* PNG_READ_SUPPORTED && PNG_ASSEMBLER_CODE_SUPPORTED */
829
830	#if defined(PNG_READ_SUPPORTED) \|\| defined(PNG_WRITE_SUPPORTED)
831	#ifdef PNG_SIZE_T
832	/* Added at libpng version 1.2.6 */
833	PNG_EXTERN png_size_t PNGAPI png_convert_size PNGARG((size_t size));
834	png_size_t PNGAPI
835	png_convert_size(size_t size)
836	{
837	if (size > (png_size_t)-1)
838	PNG_ABORT(); /* We haven't got access to png_ptr, so no png_error() */
839	return ((png_size_t)size);
840	}
841	#endif /* PNG_SIZE_T */
842
843	/* Added at libpng version 1.2.34 and 1.4.0 (moved from pngset.c) */
844	#ifdef PNG_cHRM_SUPPORTED
845	#ifdef PNG_CHECK_cHRM_SUPPORTED
846
847	/*
848	* Multiply two 32-bit numbers, V1 and V2, using 32-bit
849	* arithmetic, to produce a 64 bit result in the HI/LO words.
850	*
851	* A B
852	* x C D
853	* ------
854	* AD \|\| BD
855	* AC \|\| CB \|\| 0
856	*
857	* where A and B are the high and low 16-bit words of V1,
858	* C and D are the 16-bit words of V2, AD is the product of
859	* A and D, and X \|\| Y is (X << 16) + Y.
860	*/
861
862	void /* PRIVATE */
863	png_64bit_product (long v1, long v2, unsigned long *hi_product,
864	unsigned long *lo_product)
865	{
866	int a, b, c, d;
867	long lo, hi, x, y;
868
869	a = (v1 >> 16) & 0xffff;
870	b = v1 & 0xffff;
871	c = (v2 >> 16) & 0xffff;
872	d = v2 & 0xffff;
873
874	lo = b * d; /* BD */
875	x = a * d + c * b; /* AD + CB */
876	y = ((lo >> 16) & 0xffff) + x;
877
878	lo = (lo & 0xffff) \| ((y & 0xffff) << 16);
879	hi = (y >> 16) & 0xffff;
880
881	hi += a * c; /* AC */
882
883	*hi_product = (unsigned long)hi;
884	*lo_product = (unsigned long)lo;
885	}
886
887	int /* PRIVATE */
888	png_check_cHRM_fixed(png_structp png_ptr,
889	png_fixed_point white_x, png_fixed_point white_y, png_fixed_point red_x,
890	png_fixed_point red_y, png_fixed_point green_x, png_fixed_point green_y,
891	png_fixed_point blue_x, png_fixed_point blue_y)
892	{
893	int ret = 1;
894	unsigned long xy_hi,xy_lo,yx_hi,yx_lo;
895
896	png_debug(1, "in function png_check_cHRM_fixed");
897
898	if (png_ptr == NULL)
899	return 0;
900
901	if (white_x < 0 \|\| white_y <= 0 \|\|
902	red_x < 0 \|\| red_y < 0 \|\|
903	green_x < 0 \|\| green_y < 0 \|\|
904	blue_x < 0 \|\| blue_y < 0)
905	{
906	png_warning(png_ptr,
907	"Ignoring attempt to set negative chromaticity value");
908	ret = 0;
909	}
910	if (white_x > (png_fixed_point) PNG_UINT_31_MAX \|\|
911	white_y > (png_fixed_point) PNG_UINT_31_MAX \|\|
912	red_x > (png_fixed_point) PNG_UINT_31_MAX \|\|
913	red_y > (png_fixed_point) PNG_UINT_31_MAX \|\|
914	green_x > (png_fixed_point) PNG_UINT_31_MAX \|\|
915	green_y > (png_fixed_point) PNG_UINT_31_MAX \|\|
916	blue_x > (png_fixed_point) PNG_UINT_31_MAX \|\|
917	blue_y > (png_fixed_point) PNG_UINT_31_MAX )
918	{
919	png_warning(png_ptr,
920	"Ignoring attempt to set chromaticity value exceeding 21474.83");
921	ret = 0;
922	}
923	if (white_x > 100000L - white_y)
924	{
925	png_warning(png_ptr, "Invalid cHRM white point");
926	ret = 0;
927	}
928	if (red_x > 100000L - red_y)
929	{
930	png_warning(png_ptr, "Invalid cHRM red point");
931	ret = 0;
932	}
933	if (green_x > 100000L - green_y)
934	{
935	png_warning(png_ptr, "Invalid cHRM green point");
936	ret = 0;
937	}
938	if (blue_x > 100000L - blue_y)
939	{
940	png_warning(png_ptr, "Invalid cHRM blue point");
941	ret = 0;
942	}
943
944	png_64bit_product(green_x - red_x, blue_y - red_y, &xy_hi, &xy_lo);
945	png_64bit_product(green_y - red_y, blue_x - red_x, &yx_hi, &yx_lo);
946
947	if (xy_hi == yx_hi && xy_lo == yx_lo)
948	{
949	png_warning(png_ptr,
950	"Ignoring attempt to set cHRM RGB triangle with zero area");
951	ret = 0;
952	}
953
954	return ret;
955	}
956	#endif /* PNG_CHECK_cHRM_SUPPORTED */
957	#endif /* PNG_cHRM_SUPPORTED */
958
959	void /* PRIVATE */
960	png_check_IHDR(png_structp png_ptr,
961	png_uint_32 width, png_uint_32 height, int bit_depth,
962	int color_type, int interlace_type, int compression_type,
963	int filter_type)
964	{
965	int error = 0;
966
967	/* Check for width and height valid values */
968	if (width == 0)
969	{
970	png_warning(png_ptr, "Image width is zero in IHDR");
971	error = 1;
972	}
973
974	if (height == 0)
975	{
976	png_warning(png_ptr, "Image height is zero in IHDR");
977	error = 1;
978	}
979
980	#ifdef PNG_SET_USER_LIMITS_SUPPORTED
981	if (width > png_ptr->user_width_max \|\| width > PNG_USER_WIDTH_MAX)
982	#else
983	if (width > PNG_USER_WIDTH_MAX)
984	#endif
985	{
986	png_warning(png_ptr, "Image width exceeds user limit in IHDR");
987	error = 1;
988	}
989
990	#ifdef PNG_SET_USER_LIMITS_SUPPORTED
991	if (height > png_ptr->user_height_max \|\| height > PNG_USER_HEIGHT_MAX)
992	#else
993	if (height > PNG_USER_HEIGHT_MAX)
994	#endif
995	{
996	png_warning(png_ptr, "Image height exceeds user limit in IHDR");
997	error = 1;
998	}
999
1000	if (width > PNG_UINT_31_MAX)
1001	{
1002	png_warning(png_ptr, "Invalid image width in IHDR");
1003	error = 1;
1004	}
1005
1006	if ( height > PNG_UINT_31_MAX)
1007	{
1008	png_warning(png_ptr, "Invalid image height in IHDR");
1009	error = 1;
1010	}
1011
1012	if ( width > (PNG_UINT_32_MAX
1013	>> 3) /* 8-byte RGBA pixels */
1014	- 64 /* bigrowbuf hack */
1015	- 1 /* filter byte */
1016	- 78 / rounding of width to multiple of 8 pixels */
1017	- 8) /* extra max_pixel_depth pad */
1018	png_warning(png_ptr, "Width is too large for libpng to process pixels");
1019
1020	/* Check other values */
1021	if (bit_depth != 1 && bit_depth != 2 && bit_depth != 4 &&
1022	bit_depth != 8 && bit_depth != 16)
1023	{
1024	png_warning(png_ptr, "Invalid bit depth in IHDR");
1025	error = 1;
1026	}
1027
1028	if (color_type < 0 \|\| color_type == 1 \|\|
1029	color_type == 5 \|\| color_type > 6)
1030	{
1031	png_warning(png_ptr, "Invalid color type in IHDR");
1032	error = 1;
1033	}
1034
1035	if (((color_type == PNG_COLOR_TYPE_PALETTE) && bit_depth > 8) \|\|
1036	((color_type == PNG_COLOR_TYPE_RGB \|\|
1037	color_type == PNG_COLOR_TYPE_GRAY_ALPHA \|\|
1038	color_type == PNG_COLOR_TYPE_RGB_ALPHA) && bit_depth < 8))
1039	{
1040	png_warning(png_ptr, "Invalid color type/bit depth combination in IHDR");
1041	error = 1;
1042	}
1043
1044	if (interlace_type >= PNG_INTERLACE_LAST)
1045	{
1046	png_warning(png_ptr, "Unknown interlace method in IHDR");
1047	error = 1;
1048	}
1049
1050	if (compression_type != PNG_COMPRESSION_TYPE_BASE)
1051	{
1052	png_warning(png_ptr, "Unknown compression method in IHDR");
1053	error = 1;
1054	}
1055
1056	#ifdef PNG_MNG_FEATURES_SUPPORTED
1057	/* Accept filter_method 64 (intrapixel differencing) only if
1058	* 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
1059	* 2. Libpng did not read a PNG signature (this filter_method is only
1060	* used in PNG datastreams that are embedded in MNG datastreams) and
1061	* 3. The application called png_permit_mng_features with a mask that
1062	* included PNG_FLAG_MNG_FILTER_64 and
1063	* 4. The filter_method is 64 and
1064	* 5. The color_type is RGB or RGBA
1065	*/
1066	if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) &&
1067	png_ptr->mng_features_permitted)
1068	png_warning(png_ptr, "MNG features are not allowed in a PNG datastream");
1069
1070	if (filter_type != PNG_FILTER_TYPE_BASE)
1071	{
1072	if (!((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
1073	(filter_type == PNG_INTRAPIXEL_DIFFERENCING) &&
1074	((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) == 0) &&
1075	(color_type == PNG_COLOR_TYPE_RGB \|\|
1076	color_type == PNG_COLOR_TYPE_RGB_ALPHA)))
1077	{
1078	png_warning(png_ptr, "Unknown filter method in IHDR");
1079	error = 1;
1080	}
1081
1082	if (png_ptr->mode & PNG_HAVE_PNG_SIGNATURE)
1083	{
1084	png_warning(png_ptr, "Invalid filter method in IHDR");
1085	error = 1;
1086	}
1087	}
1088
1089	#else
1090	if (filter_type != PNG_FILTER_TYPE_BASE)
1091	{
1092	png_warning(png_ptr, "Unknown filter method in IHDR");
1093	error = 1;
1094	}
1095	#endif
1096
1097	if (error == 1)
1098	png_error(png_ptr, "Invalid IHDR data");
1099	}
1100	#endif /* defined(PNG_READ_SUPPORTED) \|\| defined(PNG_WRITE_SUPPORTED) */

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