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1 
2 /* png.c - location for general purpose libpng functions
3  *
4  * Last changed in libpng 1.2.19 August 18, 2007
5  * For conditions of distribution and use, see copyright notice in png.h
6  * Copyright (c) 1998-2007 Glenn Randers-Pehrson
7  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
8  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
9  */
10 
11 #define PNG_INTERNAL
12 #define PNG_NO_EXTERN
13 #include "png.h"
14 
15 /* Generate a compiler error if there is an old png.h in the search path. */
16 typedef version_1_2_19 Your_png_h_is_not_version_1_2_19;
17 
18 /* Version information for C files.  This had better match the version
19  * string defined in png.h.  */
20 
21 #ifdef PNG_USE_GLOBAL_ARRAYS
22 /* png_libpng_ver was changed to a function in version 1.0.5c */
23 PNG_CONST char png_libpng_ver[18] = PNG_LIBPNG_VER_STRING;
24 
25 #ifdef PNG_READ_SUPPORTED
26 
27 /* png_sig was changed to a function in version 1.0.5c */
28 /* Place to hold the signature string for a PNG file. */
29 PNG_CONST png_byte FARDATA png_sig[8] = {137, 80, 78, 71, 13, 10, 26, 10};
30 #endif /* PNG_READ_SUPPORTED */
31 
32 /* Invoke global declarations for constant strings for known chunk types */
33 PNG_IHDR;
34 PNG_IDAT;
35 PNG_IEND;
36 PNG_PLTE;
37 PNG_bKGD;
38 PNG_cHRM;
39 PNG_gAMA;
40 PNG_hIST;
41 PNG_iCCP;
42 PNG_iTXt;
43 PNG_oFFs;
44 PNG_pCAL;
45 PNG_sCAL;
46 PNG_pHYs;
47 PNG_sBIT;
48 PNG_sPLT;
49 PNG_sRGB;
50 PNG_tEXt;
51 PNG_tIME;
52 PNG_tRNS;
53 PNG_zTXt;
54 
55 #ifdef PNG_READ_SUPPORTED
56 /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
57 
58 /* start of interlace block */
59 PNG_CONST int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
60 
61 /* offset to next interlace block */
62 PNG_CONST int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
63 
64 /* start of interlace block in the y direction */
65 PNG_CONST int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
66 
67 /* offset to next interlace block in the y direction */
68 PNG_CONST int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
69 
70 /* width of interlace block (used in assembler routines only) */
71 #if defined(PNG_HAVE_MMX_COMBINE_ROW) || defined(PNG_OPTIMIZED_CODE_SUPPORTED)
72 PNG_CONST int FARDATA png_pass_width[] = {8, 4, 4, 2, 2, 1, 1};
73 #endif
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[] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
82 
83 /* Mask to determine which pixels to overwrite while displaying */
84 PNG_CONST int FARDATA png_pass_dsp_mask[]
85    = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
86 
87 #endif /* PNG_READ_SUPPORTED */
88 #endif /* PNG_USE_GLOBAL_ARRAYS */
89 
90 /* Tells libpng that we have already handled the first "num_bytes" bytes
91  * of the PNG file signature.  If the PNG data is embedded into another
92  * stream we can set num_bytes = 8 so that libpng will not attempt to read
93  * or write any of the magic bytes before it starts on the IHDR.
94  */
95 
96 #ifdef PNG_READ_SUPPORTED
97 void PNGAPI
png_set_sig_bytes(png_structp png_ptr,int num_bytes)98 png_set_sig_bytes(png_structp png_ptr, int num_bytes)
99 {
100    if(png_ptr == NULL) return;
101    png_debug(1, "in png_set_sig_bytes\n");
102    if (num_bytes > 8)
103       png_error(png_ptr, "Too many bytes for PNG signature.");
104 
105    png_ptr->sig_bytes = (png_byte)(num_bytes < 0 ? 0 : num_bytes);
106 }
107 
108 /* Checks whether the supplied bytes match the PNG signature.  We allow
109  * checking less than the full 8-byte signature so that those apps that
110  * already read the first few bytes of a file to determine the file type
111  * can simply check the remaining bytes for extra assurance.  Returns
112  * an integer less than, equal to, or greater than zero if sig is found,
113  * respectively, to be less than, to match, or be greater than the correct
114  * PNG signature (this is the same behaviour as strcmp, memcmp, etc).
115  */
116 int PNGAPI
png_sig_cmp(png_bytep sig,png_size_t start,png_size_t num_to_check)117 png_sig_cmp(png_bytep sig, png_size_t start, png_size_t num_to_check)
118 {
119    png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
120    if (num_to_check > 8)
121       num_to_check = 8;
122    else if (num_to_check < 1)
123       return (-1);
124 
125    if (start > 7)
126       return (-1);
127 
128    if (start + num_to_check > 8)
129       num_to_check = 8 - start;
130 
131    return ((int)(png_memcmp(&sig[start], &png_signature[start], num_to_check)));
132 }
133 
134 #if defined(PNG_1_0_X) || defined(PNG_1_2_X)
135 /* (Obsolete) function to check signature bytes.  It does not allow one
136  * to check a partial signature.  This function might be removed in the
137  * future - use png_sig_cmp().  Returns true (nonzero) if the file is PNG.
138  */
139 int PNGAPI
png_check_sig(png_bytep sig,int num)140 png_check_sig(png_bytep sig, int num)
141 {
142   return ((int)!png_sig_cmp(sig, (png_size_t)0, (png_size_t)num));
143 }
144 #endif
145 #endif /* PNG_READ_SUPPORTED */
146 
147 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
148 /* Function to allocate memory for zlib and clear it to 0. */
149 #ifdef PNG_1_0_X
150 voidpf PNGAPI
151 #else
152 voidpf /* private */
153 #endif
png_zalloc(voidpf png_ptr,uInt items,uInt size)154 png_zalloc(voidpf png_ptr, uInt items, uInt size)
155 {
156    png_voidp ptr;
157    png_structp p=(png_structp)png_ptr;
158    png_uint_32 save_flags=p->flags;
159    png_uint_32 num_bytes;
160 
161    if(png_ptr == NULL) return (NULL);
162    if (items > PNG_UINT_32_MAX/size)
163    {
164      png_warning (p, "Potential overflow in png_zalloc()");
165      return (NULL);
166    }
167    num_bytes = (png_uint_32)items * size;
168 
169    p->flags|=PNG_FLAG_MALLOC_NULL_MEM_OK;
170    ptr = (png_voidp)png_malloc((png_structp)png_ptr, num_bytes);
171    p->flags=save_flags;
172 
173 #if defined(PNG_1_0_X) && !defined(PNG_NO_ZALLOC_ZERO)
174    if (ptr == NULL)
175        return ((voidpf)ptr);
176 
177    if (num_bytes > (png_uint_32)0x8000L)
178    {
179       png_memset(ptr, 0, (png_size_t)0x8000L);
180       png_memset((png_bytep)ptr + (png_size_t)0x8000L, 0,
181          (png_size_t)(num_bytes - (png_uint_32)0x8000L));
182    }
183    else
184    {
185       png_memset(ptr, 0, (png_size_t)num_bytes);
186    }
187 #endif
188    return ((voidpf)ptr);
189 }
190 
191 /* function to free memory for zlib */
192 #ifdef PNG_1_0_X
193 void PNGAPI
194 #else
195 void /* private */
196 #endif
png_zfree(voidpf png_ptr,voidpf ptr)197 png_zfree(voidpf png_ptr, voidpf ptr)
198 {
199    png_free((png_structp)png_ptr, (png_voidp)ptr);
200 }
201 
202 /* Reset the CRC variable to 32 bits of 1's.  Care must be taken
203  * in case CRC is > 32 bits to leave the top bits 0.
204  */
205 void /* PRIVATE */
png_reset_crc(png_structp png_ptr)206 png_reset_crc(png_structp png_ptr)
207 {
208    png_ptr->crc = crc32(0, Z_NULL, 0);
209 }
210 
211 /* Calculate the CRC over a section of data.  We can only pass as
212  * much data to this routine as the largest single buffer size.  We
213  * also check that this data will actually be used before going to the
214  * trouble of calculating it.
215  */
216 void /* PRIVATE */
png_calculate_crc(png_structp png_ptr,png_bytep ptr,png_size_t length)217 png_calculate_crc(png_structp png_ptr, png_bytep ptr, png_size_t length)
218 {
219    int need_crc = 1;
220 
221    if (png_ptr->chunk_name[0] & 0x20)                     /* ancillary */
222    {
223       if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
224           (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
225          need_crc = 0;
226    }
227    else                                                    /* critical */
228    {
229       if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE)
230          need_crc = 0;
231    }
232 
233    if (need_crc)
234       png_ptr->crc = crc32(png_ptr->crc, ptr, (uInt)length);
235 }
236 
237 /* Allocate the memory for an info_struct for the application.  We don't
238  * really need the png_ptr, but it could potentially be useful in the
239  * future.  This should be used in favour of malloc(png_sizeof(png_info))
240  * and png_info_init() so that applications that want to use a shared
241  * libpng don't have to be recompiled if png_info changes size.
242  */
243 png_infop PNGAPI
png_create_info_struct(png_structp png_ptr)244 png_create_info_struct(png_structp png_ptr)
245 {
246    png_infop info_ptr;
247 
248    png_debug(1, "in png_create_info_struct\n");
249    if(png_ptr == NULL) return (NULL);
250 #ifdef PNG_USER_MEM_SUPPORTED
251    info_ptr = (png_infop)png_create_struct_2(PNG_STRUCT_INFO,
252       png_ptr->malloc_fn, png_ptr->mem_ptr);
253 #else
254    info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO);
255 #endif
256    if (info_ptr != NULL)
257       png_info_init_3(&info_ptr, png_sizeof(png_info));
258 
259    return (info_ptr);
260 }
261 
262 /* This function frees the memory associated with a single info struct.
263  * Normally, one would use either png_destroy_read_struct() or
264  * png_destroy_write_struct() to free an info struct, but this may be
265  * useful for some applications.
266  */
267 void PNGAPI
png_destroy_info_struct(png_structp png_ptr,png_infopp info_ptr_ptr)268 png_destroy_info_struct(png_structp png_ptr, png_infopp info_ptr_ptr)
269 {
270    png_infop info_ptr = NULL;
271    if(png_ptr == NULL) return;
272 
273    png_debug(1, "in png_destroy_info_struct\n");
274    if (info_ptr_ptr != NULL)
275       info_ptr = *info_ptr_ptr;
276 
277    if (info_ptr != NULL)
278    {
279       png_info_destroy(png_ptr, info_ptr);
280 
281 #ifdef PNG_USER_MEM_SUPPORTED
282       png_destroy_struct_2((png_voidp)info_ptr, png_ptr->free_fn,
283           png_ptr->mem_ptr);
284 #else
285       png_destroy_struct((png_voidp)info_ptr);
286 #endif
287       *info_ptr_ptr = NULL;
288    }
289 }
290 
291 /* Initialize the info structure.  This is now an internal function (0.89)
292  * and applications using it are urged to use png_create_info_struct()
293  * instead.
294  */
295 #if defined(PNG_1_0_X) || defined(PNG_1_2_X)
296 #undef png_info_init
297 void PNGAPI
png_info_init(png_infop info_ptr)298 png_info_init(png_infop info_ptr)
299 {
300    /* We only come here via pre-1.0.12-compiled applications */
301    png_info_init_3(&info_ptr, 0);
302 }
303 #endif
304 
305 void PNGAPI
png_info_init_3(png_infopp ptr_ptr,png_size_t png_info_struct_size)306 png_info_init_3(png_infopp ptr_ptr, png_size_t png_info_struct_size)
307 {
308    png_infop info_ptr = *ptr_ptr;
309 
310    if(info_ptr == NULL) return;
311 
312    png_debug(1, "in png_info_init_3\n");
313 
314    if(png_sizeof(png_info) > png_info_struct_size)
315      {
316        png_destroy_struct(info_ptr);
317        info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO);
318        *ptr_ptr = info_ptr;
319      }
320 
321    /* set everything to 0 */
322    png_memset(info_ptr, 0, png_sizeof (png_info));
323 }
324 
325 #ifdef PNG_FREE_ME_SUPPORTED
326 void PNGAPI
png_data_freer(png_structp png_ptr,png_infop info_ptr,int freer,png_uint_32 mask)327 png_data_freer(png_structp png_ptr, png_infop info_ptr,
328    int freer, png_uint_32 mask)
329 {
330    png_debug(1, "in png_data_freer\n");
331    if (png_ptr == NULL || info_ptr == NULL)
332       return;
333    if(freer == PNG_DESTROY_WILL_FREE_DATA)
334       info_ptr->free_me |= mask;
335    else if(freer == PNG_USER_WILL_FREE_DATA)
336       info_ptr->free_me &= ~mask;
337    else
338       png_warning(png_ptr,
339          "Unknown freer parameter in png_data_freer.");
340 }
341 #endif
342 
343 void PNGAPI
png_free_data(png_structp png_ptr,png_infop info_ptr,png_uint_32 mask,int num)344 png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask,
345    int num)
346 {
347    png_debug(1, "in png_free_data\n");
348    if (png_ptr == NULL || info_ptr == NULL)
349       return;
350 
351 #if defined(PNG_TEXT_SUPPORTED)
352 /* free text item num or (if num == -1) all text items */
353 #ifdef PNG_FREE_ME_SUPPORTED
354 if ((mask & PNG_FREE_TEXT) & info_ptr->free_me)
355 #else
356 if (mask & PNG_FREE_TEXT)
357 #endif
358 {
359    if (num != -1)
360    {
361      if (info_ptr->text && info_ptr->text[num].key)
362      {
363          png_free(png_ptr, info_ptr->text[num].key);
364          info_ptr->text[num].key = NULL;
365      }
366    }
367    else
368    {
369        int i;
370        for (i = 0; i < info_ptr->num_text; i++)
371            png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, i);
372        png_free(png_ptr, info_ptr->text);
373        info_ptr->text = NULL;
374        info_ptr->num_text=0;
375    }
376 }
377 #endif
378 
379 #if defined(PNG_tRNS_SUPPORTED)
380 /* free any tRNS entry */
381 #ifdef PNG_FREE_ME_SUPPORTED
382 if ((mask & PNG_FREE_TRNS) & info_ptr->free_me)
383 #else
384 if ((mask & PNG_FREE_TRNS) && (png_ptr->flags & PNG_FLAG_FREE_TRNS))
385 #endif
386 {
387     png_free(png_ptr, info_ptr->trans);
388     info_ptr->valid &= ~PNG_INFO_tRNS;
389 #ifndef PNG_FREE_ME_SUPPORTED
390     png_ptr->flags &= ~PNG_FLAG_FREE_TRNS;
391 #endif
392     info_ptr->trans = NULL;
393 }
394 #endif
395 
396 #if defined(PNG_sCAL_SUPPORTED)
397 /* free any sCAL entry */
398 #ifdef PNG_FREE_ME_SUPPORTED
399 if ((mask & PNG_FREE_SCAL) & info_ptr->free_me)
400 #else
401 if (mask & PNG_FREE_SCAL)
402 #endif
403 {
404 #if defined(PNG_FIXED_POINT_SUPPORTED) && !defined(PNG_FLOATING_POINT_SUPPORTED)
405     png_free(png_ptr, info_ptr->scal_s_width);
406     png_free(png_ptr, info_ptr->scal_s_height);
407     info_ptr->scal_s_width = NULL;
408     info_ptr->scal_s_height = NULL;
409 #endif
410     info_ptr->valid &= ~PNG_INFO_sCAL;
411 }
412 #endif
413 
414 #if defined(PNG_pCAL_SUPPORTED)
415 /* free any pCAL entry */
416 #ifdef PNG_FREE_ME_SUPPORTED
417 if ((mask & PNG_FREE_PCAL) & info_ptr->free_me)
418 #else
419 if (mask & PNG_FREE_PCAL)
420 #endif
421 {
422     png_free(png_ptr, info_ptr->pcal_purpose);
423     png_free(png_ptr, info_ptr->pcal_units);
424     info_ptr->pcal_purpose = NULL;
425     info_ptr->pcal_units = NULL;
426     if (info_ptr->pcal_params != NULL)
427     {
428         int i;
429         for (i = 0; i < (int)info_ptr->pcal_nparams; i++)
430         {
431           png_free(png_ptr, info_ptr->pcal_params[i]);
432           info_ptr->pcal_params[i]=NULL;
433         }
434         png_free(png_ptr, info_ptr->pcal_params);
435         info_ptr->pcal_params = NULL;
436     }
437     info_ptr->valid &= ~PNG_INFO_pCAL;
438 }
439 #endif
440 
441 #if defined(PNG_iCCP_SUPPORTED)
442 /* free any iCCP entry */
443 #ifdef PNG_FREE_ME_SUPPORTED
444 if ((mask & PNG_FREE_ICCP) & info_ptr->free_me)
445 #else
446 if (mask & PNG_FREE_ICCP)
447 #endif
448 {
449     png_free(png_ptr, info_ptr->iccp_name);
450     png_free(png_ptr, info_ptr->iccp_profile);
451     info_ptr->iccp_name = NULL;
452     info_ptr->iccp_profile = NULL;
453     info_ptr->valid &= ~PNG_INFO_iCCP;
454 }
455 #endif
456 
457 #if defined(PNG_sPLT_SUPPORTED)
458 /* free a given sPLT entry, or (if num == -1) all sPLT entries */
459 #ifdef PNG_FREE_ME_SUPPORTED
460 if ((mask & PNG_FREE_SPLT) & info_ptr->free_me)
461 #else
462 if (mask & PNG_FREE_SPLT)
463 #endif
464 {
465    if (num != -1)
466    {
467       if(info_ptr->splt_palettes)
468       {
469           png_free(png_ptr, info_ptr->splt_palettes[num].name);
470           png_free(png_ptr, info_ptr->splt_palettes[num].entries);
471           info_ptr->splt_palettes[num].name = NULL;
472           info_ptr->splt_palettes[num].entries = NULL;
473       }
474    }
475    else
476    {
477        if(info_ptr->splt_palettes_num)
478        {
479          int i;
480          for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
481             png_free_data(png_ptr, info_ptr, PNG_FREE_SPLT, i);
482 
483          png_free(png_ptr, info_ptr->splt_palettes);
484          info_ptr->splt_palettes = NULL;
485          info_ptr->splt_palettes_num = 0;
486        }
487        info_ptr->valid &= ~PNG_INFO_sPLT;
488    }
489 }
490 #endif
491 
492 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
493   if(png_ptr->unknown_chunk.data)
494   {
495     png_free(png_ptr, png_ptr->unknown_chunk.data);
496     png_ptr->unknown_chunk.data = NULL;
497   }
498 #ifdef PNG_FREE_ME_SUPPORTED
499 if ((mask & PNG_FREE_UNKN) & info_ptr->free_me)
500 #else
501 if (mask & PNG_FREE_UNKN)
502 #endif
503 {
504    if (num != -1)
505    {
506        if(info_ptr->unknown_chunks)
507        {
508           png_free(png_ptr, info_ptr->unknown_chunks[num].data);
509           info_ptr->unknown_chunks[num].data = NULL;
510        }
511    }
512    else
513    {
514        int i;
515 
516        if(info_ptr->unknown_chunks_num)
517        {
518          for (i = 0; i < (int)info_ptr->unknown_chunks_num; i++)
519             png_free_data(png_ptr, info_ptr, PNG_FREE_UNKN, i);
520 
521          png_free(png_ptr, info_ptr->unknown_chunks);
522          info_ptr->unknown_chunks = NULL;
523          info_ptr->unknown_chunks_num = 0;
524        }
525    }
526 }
527 #endif
528 
529 #if defined(PNG_hIST_SUPPORTED)
530 /* free any hIST entry */
531 #ifdef PNG_FREE_ME_SUPPORTED
532 if ((mask & PNG_FREE_HIST)  & info_ptr->free_me)
533 #else
534 if ((mask & PNG_FREE_HIST) && (png_ptr->flags & PNG_FLAG_FREE_HIST))
535 #endif
536 {
537     png_free(png_ptr, info_ptr->hist);
538     info_ptr->hist = NULL;
539     info_ptr->valid &= ~PNG_INFO_hIST;
540 #ifndef PNG_FREE_ME_SUPPORTED
541     png_ptr->flags &= ~PNG_FLAG_FREE_HIST;
542 #endif
543 }
544 #endif
545 
546 /* free any PLTE entry that was internally allocated */
547 #ifdef PNG_FREE_ME_SUPPORTED
548 if ((mask & PNG_FREE_PLTE) & info_ptr->free_me)
549 #else
550 if ((mask & PNG_FREE_PLTE) && (png_ptr->flags & PNG_FLAG_FREE_PLTE))
551 #endif
552 {
553     png_zfree(png_ptr, info_ptr->palette);
554     info_ptr->palette = NULL;
555     info_ptr->valid &= ~PNG_INFO_PLTE;
556 #ifndef PNG_FREE_ME_SUPPORTED
557     png_ptr->flags &= ~PNG_FLAG_FREE_PLTE;
558 #endif
559     info_ptr->num_palette = 0;
560 }
561 
562 #if defined(PNG_INFO_IMAGE_SUPPORTED)
563 /* free any image bits attached to the info structure */
564 #ifdef PNG_FREE_ME_SUPPORTED
565 if ((mask & PNG_FREE_ROWS) & info_ptr->free_me)
566 #else
567 if (mask & PNG_FREE_ROWS)
568 #endif
569 {
570     if(info_ptr->row_pointers)
571     {
572        int row;
573        for (row = 0; row < (int)info_ptr->height; row++)
574        {
575           png_free(png_ptr, info_ptr->row_pointers[row]);
576           info_ptr->row_pointers[row]=NULL;
577        }
578        png_free(png_ptr, info_ptr->row_pointers);
579        info_ptr->row_pointers=NULL;
580     }
581     info_ptr->valid &= ~PNG_INFO_IDAT;
582 }
583 #endif
584 
585 #ifdef PNG_FREE_ME_SUPPORTED
586    if(num == -1)
587      info_ptr->free_me &= ~mask;
588    else
589      info_ptr->free_me &= ~(mask & ~PNG_FREE_MUL);
590 #endif
591 }
592 
593 /* This is an internal routine to free any memory that the info struct is
594  * pointing to before re-using it or freeing the struct itself.  Recall
595  * that png_free() checks for NULL pointers for us.
596  */
597 void /* PRIVATE */
png_info_destroy(png_structp png_ptr,png_infop info_ptr)598 png_info_destroy(png_structp png_ptr, png_infop info_ptr)
599 {
600    png_debug(1, "in png_info_destroy\n");
601 
602    png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
603 
604 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
605    if (png_ptr->num_chunk_list)
606    {
607        png_free(png_ptr, png_ptr->chunk_list);
608        png_ptr->chunk_list=NULL;
609        png_ptr->num_chunk_list=0;
610    }
611 #endif
612 
613    png_info_init_3(&info_ptr, png_sizeof(png_info));
614 }
615 #endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */
616 
617 /* This function returns a pointer to the io_ptr associated with the user
618  * functions.  The application should free any memory associated with this
619  * pointer before png_write_destroy() or png_read_destroy() are called.
620  */
621 png_voidp PNGAPI
png_get_io_ptr(png_structp png_ptr)622 png_get_io_ptr(png_structp png_ptr)
623 {
624    if(png_ptr == NULL) return (NULL);
625    return (png_ptr->io_ptr);
626 }
627 
628 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
629 #if !defined(PNG_NO_STDIO)
630 /* Initialize the default input/output functions for the PNG file.  If you
631  * use your own read or write routines, you can call either png_set_read_fn()
632  * or png_set_write_fn() instead of png_init_io().  If you have defined
633  * PNG_NO_STDIO, you must use a function of your own because "FILE *" isn't
634  * necessarily available.
635  */
636 void PNGAPI
png_init_io(png_structp png_ptr,png_FILE_p fp)637 png_init_io(png_structp png_ptr, png_FILE_p fp)
638 {
639    png_debug(1, "in png_init_io\n");
640    if(png_ptr == NULL) return;
641    png_ptr->io_ptr = (png_voidp)fp;
642 }
643 #endif
644 
645 #if defined(PNG_TIME_RFC1123_SUPPORTED)
646 /* Convert the supplied time into an RFC 1123 string suitable for use in
647  * a "Creation Time" or other text-based time string.
648  */
649 png_charp PNGAPI
png_convert_to_rfc1123(png_structp png_ptr,png_timep ptime)650 png_convert_to_rfc1123(png_structp png_ptr, png_timep ptime)
651 {
652    static PNG_CONST char short_months[12][4] =
653         {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
654          "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
655 
656    if(png_ptr == NULL) return (NULL);
657    if (png_ptr->time_buffer == NULL)
658    {
659       png_ptr->time_buffer = (png_charp)png_malloc(png_ptr, (png_uint_32)(29*
660          png_sizeof(char)));
661    }
662 
663 #if defined(_WIN32_WCE)
664    {
665       wchar_t time_buf[29];
666       wsprintf(time_buf, TEXT("%d %S %d %02d:%02d:%02d +0000"),
667           ptime->day % 32, short_months[(ptime->month - 1) % 12],
668         ptime->year, ptime->hour % 24, ptime->minute % 60,
669           ptime->second % 61);
670       WideCharToMultiByte(CP_ACP, 0, time_buf, -1, png_ptr->time_buffer, 29,
671           NULL, NULL);
672    }
673 #else
674 #ifdef USE_FAR_KEYWORD
675    {
676       char near_time_buf[29];
677       png_snprintf6(near_time_buf,29,"%d %s %d %02d:%02d:%02d +0000",
678           ptime->day % 32, short_months[(ptime->month - 1) % 12],
679           ptime->year, ptime->hour % 24, ptime->minute % 60,
680           ptime->second % 61);
681       png_memcpy(png_ptr->time_buffer, near_time_buf,
682           29*png_sizeof(char));
683    }
684 #else
685    png_snprintf6(png_ptr->time_buffer,29,"%d %s %d %02d:%02d:%02d +0000",
686        ptime->day % 32, short_months[(ptime->month - 1) % 12],
687        ptime->year, ptime->hour % 24, ptime->minute % 60,
688        ptime->second % 61);
689 #endif
690 #endif /* _WIN32_WCE */
691    return ((png_charp)png_ptr->time_buffer);
692 }
693 #endif /* PNG_TIME_RFC1123_SUPPORTED */
694 
695 #endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */
696 
697 png_charp PNGAPI
png_get_copyright(png_structp png_ptr)698 png_get_copyright(png_structp png_ptr)
699 {
700    png_ptr = png_ptr;  /* silence compiler warning about unused png_ptr */
701    return ((png_charp) "\n libpng version 1.2.19 - August 18, 2007\n\
702    Copyright (c) 1998-2007 Glenn Randers-Pehrson\n\
703    Copyright (c) 1996-1997 Andreas Dilger\n\
704    Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.\n");
705 }
706 
707 /* The following return the library version as a short string in the
708  * format 1.0.0 through 99.99.99zz.  To get the version of *.h files
709  * used with your application, print out PNG_LIBPNG_VER_STRING, which
710  * is defined in png.h.
711  * Note: now there is no difference between png_get_libpng_ver() and
712  * png_get_header_ver().  Due to the version_nn_nn_nn typedef guard,
713  * it is guaranteed that png.c uses the correct version of png.h.
714  */
715 png_charp PNGAPI
png_get_libpng_ver(png_structp png_ptr)716 png_get_libpng_ver(png_structp png_ptr)
717 {
718    /* Version of *.c files used when building libpng */
719    png_ptr = png_ptr;  /* silence compiler warning about unused png_ptr */
720    return ((png_charp) PNG_LIBPNG_VER_STRING);
721 }
722 
723 png_charp PNGAPI
png_get_header_ver(png_structp png_ptr)724 png_get_header_ver(png_structp png_ptr)
725 {
726    /* Version of *.h files used when building libpng */
727    png_ptr = png_ptr;  /* silence compiler warning about unused png_ptr */
728    return ((png_charp) PNG_LIBPNG_VER_STRING);
729 }
730 
731 png_charp PNGAPI
png_get_header_version(png_structp png_ptr)732 png_get_header_version(png_structp png_ptr)
733 {
734    /* Returns longer string containing both version and date */
735    png_ptr = png_ptr;  /* silence compiler warning about unused png_ptr */
736    return ((png_charp) PNG_HEADER_VERSION_STRING
737 #ifdef PNG_READ_SUPPORTED
738 #  ifdef PNG_USE_PNGGCCRD
739 #    ifdef __x86_64__
740 #      ifdef __PIC__
741    "     (PNGGCRD x86_64, PIC)\n"
742 #      else
743 #        ifdef PNG_THREAD_UNSAFE_OK
744    "     (PNGGCRD x86_64, Thread unsafe)\n"
745 #        else
746    "     (PNGGCRD x86_64, Thread safe)\n"
747 #        endif
748 #      endif
749 #    else
750 #    ifdef PNG_THREAD_UNSAFE_OK
751    "     (PNGGCRD, Thread unsafe)\n"
752 #      else
753    "     (PNGGCRD, Thread safe)\n"
754 #      endif
755 #    endif
756 #  else
757 #    ifdef PNG_USE_PNGVCRD
758 #      ifdef __x86_64__
759    "     (x86_64 PNGVCRD)\n"
760 #      else
761    "     (PNGVCRD)\n"
762 #      endif
763 #    else
764 #      ifdef __x86_64__
765 #        ifdef PNG_OPTIMIZED_CODE_SUPPORTED
766    "     (x86_64 OPTIMIZED)\n"
767 #        else
768    "     (x86_64 NOT OPTIMIZED)\n"
769 #        endif
770 #      else
771 #        ifdef PNG_OPTIMIZED_CODE_SUPPORTED
772    "     (OPTIMIZED)\n"
773 #        else
774    "     (NOT OPTIMIZED)\n"
775 #        endif
776 #      endif
777 #    endif
778 #  endif
779 #else
780    "     (NO READ SUPPORT)\n"
781 #endif
782    );
783 }
784 
785 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
786 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
787 int PNGAPI
png_handle_as_unknown(png_structp png_ptr,png_bytep chunk_name)788 png_handle_as_unknown(png_structp png_ptr, png_bytep chunk_name)
789 {
790    /* check chunk_name and return "keep" value if it's on the list, else 0 */
791    int i;
792    png_bytep p;
793    if(png_ptr == NULL || chunk_name == NULL || png_ptr->num_chunk_list<=0)
794       return 0;
795    p=png_ptr->chunk_list+png_ptr->num_chunk_list*5-5;
796    for (i = png_ptr->num_chunk_list; i; i--, p-=5)
797       if (!png_memcmp(chunk_name, p, 4))
798         return ((int)*(p+4));
799    return 0;
800 }
801 #endif
802 
803 /* This function, added to libpng-1.0.6g, is untested. */
804 int PNGAPI
png_reset_zstream(png_structp png_ptr)805 png_reset_zstream(png_structp png_ptr)
806 {
807    if (png_ptr == NULL) return Z_STREAM_ERROR;
808    return (inflateReset(&png_ptr->zstream));
809 }
810 #endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */
811 
812 /* This function was added to libpng-1.0.7 */
813 png_uint_32 PNGAPI
png_access_version_number(void)814 png_access_version_number(void)
815 {
816    /* Version of *.c files used when building libpng */
817    return((png_uint_32) PNG_LIBPNG_VER);
818 }
819 
820 
821 #if defined(PNG_READ_SUPPORTED) && defined(PNG_ASSEMBLER_CODE_SUPPORTED)
822 #if !defined(PNG_1_0_X)
823 #if defined(PNG_MMX_CODE_SUPPORTED)
824 /* this INTERNAL function was added to libpng 1.2.0 */
825 void /* PRIVATE */
png_init_mmx_flags(png_structp png_ptr)826 png_init_mmx_flags (png_structp png_ptr)
827 {
828     if(png_ptr == NULL) return;
829     png_ptr->mmx_rowbytes_threshold = 0;
830     png_ptr->mmx_bitdepth_threshold = 0;
831 
832 #  if (defined(PNG_USE_PNGVCRD) || defined(PNG_USE_PNGGCCRD))
833 
834     png_ptr->asm_flags |= PNG_ASM_FLAG_MMX_SUPPORT_COMPILED;
835 
836     if (png_mmx_support() > 0) {
837         png_ptr->asm_flags |= PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
838 #    ifdef PNG_HAVE_MMX_COMBINE_ROW
839                               | PNG_ASM_FLAG_MMX_READ_COMBINE_ROW
840 #    endif
841 #    ifdef PNG_HAVE_MMX_READ_INTERLACE
842                               | PNG_ASM_FLAG_MMX_READ_INTERLACE
843 #    endif
844 #    ifndef PNG_HAVE_MMX_READ_FILTER_ROW
845                               ;
846 #    else
847                               | PNG_ASM_FLAG_MMX_READ_FILTER_SUB
848                               | PNG_ASM_FLAG_MMX_READ_FILTER_UP
849                               | PNG_ASM_FLAG_MMX_READ_FILTER_AVG
850                               | PNG_ASM_FLAG_MMX_READ_FILTER_PAETH ;
851 
852         png_ptr->mmx_rowbytes_threshold = PNG_MMX_ROWBYTES_THRESHOLD_DEFAULT;
853         png_ptr->mmx_bitdepth_threshold = PNG_MMX_BITDEPTH_THRESHOLD_DEFAULT;
854 #    endif
855     } else {
856         png_ptr->asm_flags &= ~( PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
857                                | PNG_MMX_READ_FLAGS
858                                | PNG_MMX_WRITE_FLAGS );
859     }
860 
861 #  else /* !(PNGVCRD || PNGGCCRD) */
862 
863     /* clear all MMX flags; no support is compiled in */
864     png_ptr->asm_flags &= ~( PNG_MMX_FLAGS );
865 
866 #  endif /* ?(PNGVCRD || PNGGCCRD) */
867 }
868 
869 #endif /* !(PNG_MMX_CODE_SUPPORTED) */
870 
871 /* this function was added to libpng 1.2.0 */
872 #if !defined(PNG_USE_PNGGCCRD) && \
873     !(defined(PNG_MMX_CODE_SUPPORTED) && defined(PNG_USE_PNGVCRD))
874 int PNGAPI
png_mmx_support(void)875 png_mmx_support(void)
876 {
877     return -1;
878 }
879 #endif
880 #endif /* PNG_1_0_X */
881 #endif /* PNG_READ_SUPPORTED && PNG_ASSEMBLER_CODE_SUPPORTED */
882 
883 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
884 #ifdef PNG_SIZE_T
885 /* Added at libpng version 1.2.6 */
886    PNG_EXTERN png_size_t PNGAPI png_convert_size PNGARG((size_t size));
887 png_size_t PNGAPI
png_convert_size(size_t size)888 png_convert_size(size_t size)
889 {
890   if (size > (png_size_t)-1)
891      PNG_ABORT();  /* We haven't got access to png_ptr, so no png_error() */
892   return ((png_size_t)size);
893 }
894 #endif /* PNG_SIZE_T */
895 #endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */
896