1
2/* png.c - location for general purpose libpng functions
3 *
4 * Last changed in libpng 1.2.46 [February 25, 2011]
5 * Copyright (c) 1998-2011 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. */
20typedef version_1_2_46 Your_png_h_is_not_version_1_2_46;
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 */
28PNG_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. */
34PNG_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 */
38PNG_IHDR;
39PNG_IDAT;
40PNG_IEND;
41PNG_PLTE;
42PNG_bKGD;
43PNG_cHRM;
44PNG_gAMA;
45PNG_hIST;
46PNG_iCCP;
47PNG_iTXt;
48PNG_oFFs;
49PNG_pCAL;
50PNG_sCAL;
51PNG_pHYs;
52PNG_sBIT;
53PNG_sPLT;
54PNG_sRGB;
55PNG_tEXt;
56PNG_tIME;
57PNG_tRNS;
58PNG_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 */
64PNG_CONST int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
65
66/* Offset to next interlace block */
67PNG_CONST int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
68
69/* Start of interlace block in the y direction */
70PNG_CONST int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
71
72/* Offset to next interlace block in the y direction */
73PNG_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
77PNG_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 */
81PNG_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 */
85PNG_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
98void PNGAPI
99png_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 */
120int PNGAPI
121png_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 */
143int PNGAPI
144png_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
154voidpf PNGAPI
155#else
156voidpf /* PRIVATE */
157#endif
158png_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
198void PNGAPI
199#else
200void /* PRIVATE */
201#endif
202png_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 */
210void /* PRIVATE */
211png_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 */
221void /* PRIVATE */
222png_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 */
248png_infop PNGAPI
249png_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 */
275void PNGAPI
276png_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
308void PNGAPI
309png_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
316void PNGAPI
317png_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
338void PNGAPI
339png_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
357void PNGAPI
358png_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 */
613void /* PRIVATE */
614png_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 */
637png_voidp PNGAPI
638png_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 */
653void PNGAPI
654png_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 */
669png_charp PNGAPI
670png_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
718png_charp PNGAPI
719png_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 1.2.46 - July 9, 2011" PNG_STRING_NEWLINE \
728     "Copyright (c) 1998-2011 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 1.2.46 - July 9, 2011\
734      Copyright (c) 1998-2011 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 */
749png_charp PNGAPI
750png_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
757png_charp PNGAPI
758png_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
765png_charp PNGAPI
766png_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
783int PNGAPI
784png_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. */
800int PNGAPI
801png_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 */
810png_uint_32 PNGAPI
811png_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 */
821int PNGAPI
822png_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));
834png_size_t PNGAPI
835png_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
862void /* PRIVATE */
863png_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
887int /* PRIVATE */
888png_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
959void /* PRIVATE */
960png_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                 - 7*8      /* 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) */
1101