2 /* png.c - location for general purpose libpng functions
4 * libpng version 1.0.9 - January 31, 2001
5 * Copyright (c) 1998-2001 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.)
15 /* Generate a compiler error if there is an old png.h in the search path. */
16 typedef version_1_0_9 Your_png_h_is_not_version_1_0_9;
18 /* Version information for C files. This had better match the version
19 * string defined in png.h. */
21 #ifdef PNG_USE_GLOBAL_ARRAYS
22 /* png_libpng_ver was changed to a function in version 1.0.5c */
23 const char png_libpng_ver[18] = "1.0.9";
25 /* png_sig was changed to a function in version 1.0.5c */
26 /* Place to hold the signature string for a PNG file. */
27 const png_byte FARDATA png_sig[8] = {137, 80, 78, 71, 13, 10, 26, 10};
29 /* Invoke global declarations for constant strings for known chunk types */
52 /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
54 /* start of interlace block */
55 const int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
57 /* offset to next interlace block */
58 const int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
60 /* start of interlace block in the y direction */
61 const int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
63 /* offset to next interlace block in the y direction */
64 const int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
66 /* width of interlace block (used in assembler routines only) */
67 #ifdef PNG_HAVE_ASSEMBLER_COMBINE_ROW
68 const int FARDATA png_pass_width[] = {8, 4, 4, 2, 2, 1, 1};
71 /* Height of interlace block. This is not currently used - if you need
72 * it, uncomment it here and in png.h
73 const int FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
76 /* Mask to determine which pixels are valid in a pass */
77 const int FARDATA png_pass_mask[] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
79 /* Mask to determine which pixels to overwrite while displaying */
80 const int FARDATA png_pass_dsp_mask[]
81 = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
85 /* Tells libpng that we have already handled the first "num_bytes" bytes
86 * of the PNG file signature. If the PNG data is embedded into another
87 * stream we can set num_bytes = 8 so that libpng will not attempt to read
88 * or write any of the magic bytes before it starts on the IHDR.
92 png_set_sig_bytes(png_structp png_ptr, int num_bytes)
94 png_debug(1, "in png_set_sig_bytes\n");
96 png_error(png_ptr, "Too many bytes for PNG signature.");
98 png_ptr->sig_bytes = (png_byte)(num_bytes < 0 ? 0 : num_bytes);
101 /* Checks whether the supplied bytes match the PNG signature. We allow
102 * checking less than the full 8-byte signature so that those apps that
103 * already read the first few bytes of a file to determine the file type
104 * can simply check the remaining bytes for extra assurance. Returns
105 * an integer less than, equal to, or greater than zero if sig is found,
106 * respectively, to be less than, to match, or be greater than the correct
107 * PNG signature (this is the same behaviour as strcmp, memcmp, etc).
110 png_sig_cmp(png_bytep sig, png_size_t start, png_size_t num_to_check)
112 png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
113 if (num_to_check > 8)
115 else if (num_to_check < 1)
121 if (start + num_to_check > 8)
122 num_to_check = 8 - start;
124 return ((int)(png_memcmp(&sig[start], &png_signature[start], num_to_check)));
127 /* (Obsolete) function to check signature bytes. It does not allow one
128 * to check a partial signature. This function might be removed in the
129 * future - use png_sig_cmp(). Returns true (nonzero) if the file is a PNG.
132 png_check_sig(png_bytep sig, int num)
134 return ((int)!png_sig_cmp(sig, (png_size_t)0, (png_size_t)num));
137 /* Function to allocate memory for zlib and clear it to 0. */
139 png_zalloc(voidpf png_ptr, uInt items, uInt size)
141 png_uint_32 num_bytes = (png_uint_32)items * size;
142 png_voidp ptr = (png_voidp)png_malloc((png_structp)png_ptr, num_bytes);
144 #ifndef PNG_NO_ZALLOC_ZERO
145 if (num_bytes > (png_uint_32)0x8000L)
147 png_memset(ptr, 0, (png_size_t)0x8000L);
148 png_memset((png_bytep)ptr + (png_size_t)0x8000L, 0,
149 (png_size_t)(num_bytes - (png_uint_32)0x8000L));
153 png_memset(ptr, 0, (png_size_t)num_bytes);
156 return ((voidpf)ptr);
159 /* function to free memory for zlib */
161 png_zfree(voidpf png_ptr, voidpf ptr)
163 png_free((png_structp)png_ptr, (png_voidp)ptr);
166 /* Reset the CRC variable to 32 bits of 1's. Care must be taken
167 * in case CRC is > 32 bits to leave the top bits 0.
170 png_reset_crc(png_structp png_ptr)
172 png_ptr->crc = crc32(0, Z_NULL, 0);
175 /* Calculate the CRC over a section of data. We can only pass as
176 * much data to this routine as the largest single buffer size. We
177 * also check that this data will actually be used before going to the
178 * trouble of calculating it.
181 png_calculate_crc(png_structp png_ptr, png_bytep ptr, png_size_t length)
185 if (png_ptr->chunk_name[0] & 0x20) /* ancillary */
187 if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
188 (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
193 if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE)
198 png_ptr->crc = crc32(png_ptr->crc, ptr, (uInt)length);
201 /* Allocate the memory for an info_struct for the application. We don't
202 * really need the png_ptr, but it could potentially be useful in the
203 * future. This should be used in favour of malloc(sizeof(png_info))
204 * and png_info_init() so that applications that want to use a shared
205 * libpng don't have to be recompiled if png_info changes size.
208 png_create_info_struct(png_structp png_ptr)
212 png_debug(1, "in png_create_info_struct\n");
213 if(png_ptr == NULL) return (NULL);
214 #ifdef PNG_USER_MEM_SUPPORTED
215 if ((info_ptr = (png_infop)png_create_struct_2(PNG_STRUCT_INFO,
216 png_ptr->malloc_fn)) != NULL)
218 if ((info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO)) != NULL)
221 png_info_init(info_ptr);
227 /* This function frees the memory associated with a single info struct.
228 * Normally, one would use either png_destroy_read_struct() or
229 * png_destroy_write_struct() to free an info struct, but this may be
230 * useful for some applications.
233 png_destroy_info_struct(png_structp png_ptr, png_infopp info_ptr_ptr)
235 png_infop info_ptr = NULL;
237 png_debug(1, "in png_destroy_info_struct\n");
238 if (info_ptr_ptr != NULL)
239 info_ptr = *info_ptr_ptr;
241 if (info_ptr != NULL)
243 png_info_destroy(png_ptr, info_ptr);
245 #ifdef PNG_USER_MEM_SUPPORTED
246 png_destroy_struct_2((png_voidp)info_ptr, png_ptr->free_fn);
248 png_destroy_struct((png_voidp)info_ptr);
250 *info_ptr_ptr = (png_infop)NULL;
254 /* Initialize the info structure. This is now an internal function (0.89)
255 * and applications using it are urged to use png_create_info_struct()
259 png_info_init(png_infop info_ptr)
261 png_debug(1, "in png_info_init\n");
262 /* set everything to 0 */
263 png_memset(info_ptr, 0, sizeof (png_info));
266 #ifdef PNG_FREE_ME_SUPPORTED
268 png_data_freer(png_structp png_ptr, png_infop info_ptr,
269 int freer, png_uint_32 mask)
271 png_debug(1, "in png_data_freer\n");
272 if (png_ptr == NULL || info_ptr == NULL)
274 if(freer == PNG_DESTROY_WILL_FREE_DATA)
275 info_ptr->free_me |= mask;
276 else if(freer == PNG_USER_WILL_FREE_DATA)
277 info_ptr->free_me &= ~mask;
280 "Unknown freer parameter in png_data_freer.");
285 png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask, int num)
287 png_debug(1, "in png_free_data\n");
288 if (png_ptr == NULL || info_ptr == NULL)
291 #if defined(PNG_TEXT_SUPPORTED)
292 /* free text item num or (if num == -1) all text items */
293 #ifdef PNG_FREE_ME_SUPPORTED
294 if ((mask & PNG_FREE_TEXT) & info_ptr->free_me)
296 if (mask & PNG_FREE_TEXT)
301 if (info_ptr->text && info_ptr->text[num].key)
303 png_free(png_ptr, info_ptr->text[num].key);
304 info_ptr->text[num].key = NULL;
310 for (i = 0; i < info_ptr->num_text; i++)
311 png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, i);
312 png_free(png_ptr, info_ptr->text);
313 info_ptr->text = NULL;
314 info_ptr->num_text=0;
319 #if defined(PNG_tRNS_SUPPORTED)
320 /* free any tRNS entry */
321 #ifdef PNG_FREE_ME_SUPPORTED
322 if ((mask & PNG_FREE_TRNS) & info_ptr->free_me)
324 if ((mask & PNG_FREE_TRNS) && (png_ptr->flags & PNG_FLAG_FREE_TRNS))
327 png_free(png_ptr, info_ptr->trans);
328 info_ptr->valid &= ~PNG_INFO_tRNS;
329 info_ptr->trans = NULL;
333 #if defined(PNG_sCAL_SUPPORTED)
334 /* free any sCAL entry */
335 #ifdef PNG_FREE_ME_SUPPORTED
336 if ((mask & PNG_FREE_SCAL) & info_ptr->free_me)
338 if (mask & PNG_FREE_SCAL)
341 #if defined(PNG_FIXED_POINT_SUPPORTED) && !defined(PNG_FLOATING_POINT_SUPPORTED)
342 png_free(png_ptr, info_ptr->scal_s_width);
343 png_free(png_ptr, info_ptr->scal_s_height);
344 info_ptr->scal_s_width = NULL;
345 info_ptr->scal_s_height = NULL;
347 info_ptr->valid &= ~PNG_INFO_sCAL;
351 #if defined(PNG_pCAL_SUPPORTED)
352 /* free any pCAL entry */
353 #ifdef PNG_FREE_ME_SUPPORTED
354 if ((mask & PNG_FREE_PCAL) & info_ptr->free_me)
356 if (mask & PNG_FREE_PCAL)
359 png_free(png_ptr, info_ptr->pcal_purpose);
360 png_free(png_ptr, info_ptr->pcal_units);
361 info_ptr->pcal_purpose = NULL;
362 info_ptr->pcal_units = NULL;
363 if (info_ptr->pcal_params != NULL)
366 for (i = 0; i < (int)info_ptr->pcal_nparams; i++)
368 png_free(png_ptr, info_ptr->pcal_params[i]);
369 info_ptr->pcal_params[i]=NULL;
371 png_free(png_ptr, info_ptr->pcal_params);
372 info_ptr->pcal_params = NULL;
374 info_ptr->valid &= ~PNG_INFO_pCAL;
378 #if defined(PNG_iCCP_SUPPORTED)
379 /* free any iCCP entry */
380 #ifdef PNG_FREE_ME_SUPPORTED
381 if ((mask & PNG_FREE_ICCP) & info_ptr->free_me)
383 if (mask & PNG_FREE_ICCP)
386 png_free(png_ptr, info_ptr->iccp_name);
387 png_free(png_ptr, info_ptr->iccp_profile);
388 info_ptr->iccp_name = NULL;
389 info_ptr->iccp_profile = NULL;
390 info_ptr->valid &= ~PNG_INFO_iCCP;
394 #if defined(PNG_sPLT_SUPPORTED)
395 /* free a given sPLT entry, or (if num == -1) all sPLT entries */
396 #ifdef PNG_FREE_ME_SUPPORTED
397 if ((mask & PNG_FREE_SPLT) & info_ptr->free_me)
399 if (mask & PNG_FREE_SPLT)
404 if(info_ptr->splt_palettes)
406 png_free(png_ptr, info_ptr->splt_palettes[num].name);
407 png_free(png_ptr, info_ptr->splt_palettes[num].entries);
408 info_ptr->splt_palettes[num].name = NULL;
409 info_ptr->splt_palettes[num].entries = NULL;
414 if(info_ptr->splt_palettes_num)
417 for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
418 png_free_data(png_ptr, info_ptr, PNG_FREE_SPLT, i);
420 png_free(png_ptr, info_ptr->splt_palettes);
421 info_ptr->splt_palettes = NULL;
422 info_ptr->splt_palettes_num = 0;
424 info_ptr->valid &= ~PNG_INFO_sPLT;
429 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
430 #ifdef PNG_FREE_ME_SUPPORTED
431 if ((mask & PNG_FREE_UNKN) & info_ptr->free_me)
433 if (mask & PNG_FREE_UNKN)
438 if(info_ptr->unknown_chunks)
440 png_free(png_ptr, info_ptr->unknown_chunks[num].data);
441 info_ptr->unknown_chunks[num].data = NULL;
448 if(info_ptr->unknown_chunks_num)
450 for (i = 0; i < (int)info_ptr->unknown_chunks_num; i++)
451 png_free_data(png_ptr, info_ptr, PNG_FREE_UNKN, i);
453 png_free(png_ptr, info_ptr->unknown_chunks);
454 info_ptr->unknown_chunks = NULL;
455 info_ptr->unknown_chunks_num = 0;
461 #if defined(PNG_hIST_SUPPORTED)
462 /* free any hIST entry */
463 #ifdef PNG_FREE_ME_SUPPORTED
464 if ((mask & PNG_FREE_HIST) & info_ptr->free_me)
466 if ((mask & PNG_FREE_HIST) && (png_ptr->flags & PNG_FLAG_FREE_HIST))
469 png_free(png_ptr, info_ptr->hist);
470 info_ptr->hist = NULL;
471 info_ptr->valid &= ~PNG_INFO_hIST;
475 /* free any PLTE entry that was internally allocated */
476 #ifdef PNG_FREE_ME_SUPPORTED
477 if ((mask & PNG_FREE_PLTE) & info_ptr->free_me)
479 if ((mask & PNG_FREE_PLTE) && (png_ptr->flags & PNG_FLAG_FREE_PLTE))
482 png_zfree(png_ptr, info_ptr->palette);
483 info_ptr->palette = NULL;
484 info_ptr->valid &= ~PNG_INFO_PLTE;
485 info_ptr->num_palette = 0;
488 #if defined(PNG_INFO_IMAGE_SUPPORTED)
489 /* free any image bits attached to the info structure */
490 #ifdef PNG_FREE_ME_SUPPORTED
491 if ((mask & PNG_FREE_ROWS) & info_ptr->free_me)
493 if (mask & PNG_FREE_ROWS)
496 if(info_ptr->row_pointers)
499 for (row = 0; row < (int)info_ptr->height; row++)
501 png_free(png_ptr, info_ptr->row_pointers[row]);
502 info_ptr->row_pointers[row]=NULL;
504 png_free(png_ptr, info_ptr->row_pointers);
505 info_ptr->row_pointers=NULL;
507 info_ptr->valid &= ~PNG_INFO_IDAT;
511 #ifdef PNG_FREE_ME_SUPPORTED
513 info_ptr->free_me &= ~mask;
515 info_ptr->free_me &= ~(mask & ~PNG_FREE_MUL);
519 /* This is an internal routine to free any memory that the info struct is
520 * pointing to before re-using it or freeing the struct itself. Recall
521 * that png_free() checks for NULL pointers for us.
524 png_info_destroy(png_structp png_ptr, png_infop info_ptr)
526 png_debug(1, "in png_info_destroy\n");
528 png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
530 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
531 if (png_ptr->num_chunk_list)
533 png_free(png_ptr, png_ptr->chunk_list);
534 png_ptr->chunk_list=NULL;
535 png_ptr->num_chunk_list=0;
539 png_info_init(info_ptr);
542 /* This function returns a pointer to the io_ptr associated with the user
543 * functions. The application should free any memory associated with this
544 * pointer before png_write_destroy() or png_read_destroy() are called.
547 png_get_io_ptr(png_structp png_ptr)
549 return (png_ptr->io_ptr);
552 #if !defined(PNG_NO_STDIO)
553 /* Initialize the default input/output functions for the PNG file. If you
554 * use your own read or write routines, you can call either png_set_read_fn()
555 * or png_set_write_fn() instead of png_init_io(). If you have defined
556 * PNG_NO_STDIO, you must use a function of your own because "FILE *" isn't
557 * necessarily available.
560 png_init_io(png_structp png_ptr, png_FILE_p fp)
562 png_debug(1, "in png_init_io\n");
563 png_ptr->io_ptr = (png_voidp)fp;
567 #if defined(PNG_TIME_RFC1123_SUPPORTED)
568 /* Convert the supplied time into an RFC 1123 string suitable for use in
569 * a "Creation Time" or other text-based time string.
572 png_convert_to_rfc1123(png_structp png_ptr, png_timep ptime)
574 static PNG_CONST char short_months[12][4] =
575 {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
576 "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
578 if (png_ptr->time_buffer == NULL)
580 png_ptr->time_buffer = (png_charp)png_malloc(png_ptr, (png_uint_32)(29*
584 #if defined(_WIN32_WCE)
586 wchar_t time_buf[29];
587 wsprintf(time_buf, TEXT("%d %S %d %02d:%02d:%02d +0000"),
588 ptime->day % 32, short_months[(ptime->month - 1) % 12],
589 ptime->year, ptime->hour % 24, ptime->minute % 60,
591 WideCharToMultiByte(CP_ACP, 0, time_buf, -1, png_ptr->time_buffer, 29,
595 #ifdef USE_FAR_KEYWORD
597 char near_time_buf[29];
598 sprintf(near_time_buf, "%d %s %d %02d:%02d:%02d +0000",
599 ptime->day % 32, short_months[(ptime->month - 1) % 12],
600 ptime->year, ptime->hour % 24, ptime->minute % 60,
602 png_memcpy(png_ptr->time_buffer, near_time_buf,
606 sprintf(png_ptr->time_buffer, "%d %s %d %02d:%02d:%02d +0000",
607 ptime->day % 32, short_months[(ptime->month - 1) % 12],
608 ptime->year, ptime->hour % 24, ptime->minute % 60,
611 #endif /* _WIN32_WCE */
612 return ((png_charp)png_ptr->time_buffer);
614 #endif /* PNG_TIME_RFC1123_SUPPORTED */
617 /* Signature string for a PNG file. */
621 return ((png_bytep)"\211\120\116\107\015\012\032\012");
626 png_get_copyright(png_structp png_ptr)
628 if (png_ptr != NULL || png_ptr == NULL) /* silence compiler warning */
629 return ((png_charp) "\n libpng version 1.0.9 - January 31, 2001\n\
630 Copyright (c) 1998-2001 Glenn Randers-Pehrson\n\
631 Copyright (c) 1996, 1997 Andreas Dilger\n\
632 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.\n");
633 return ((png_charp) "");
636 /* The following return the library version as a short string in the
637 * format 1.0.0 through 99.99.99zz. To get the version of *.h files used
638 * with your application, print out PNG_LIBPNG_VER_STRING, which is defined
643 png_get_libpng_ver(png_structp png_ptr)
645 /* Version of *.c files used when building libpng */
646 if(png_ptr != NULL) /* silence compiler warning about unused png_ptr */
647 return((png_charp) "1.0.9");
648 return((png_charp) "1.0.9");
652 png_get_header_ver(png_structp png_ptr)
654 /* Version of *.h files used when building libpng */
655 if(png_ptr != NULL) /* silence compiler warning about unused png_ptr */
656 return((png_charp) PNG_LIBPNG_VER_STRING);
657 return((png_charp) PNG_LIBPNG_VER_STRING);
661 png_get_header_version(png_structp png_ptr)
663 /* Returns longer string containing both version and date */
664 if(png_ptr != NULL) /* silence compiler warning about unused png_ptr */
665 return((png_charp) PNG_HEADER_VERSION_STRING);
666 return((png_charp) PNG_HEADER_VERSION_STRING);
669 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
671 png_handle_as_unknown(png_structp png_ptr, png_bytep chunk_name)
673 /* check chunk_name and return "keep" value if it's on the list, else 0 */
676 if((png_ptr == NULL && chunk_name == NULL) || png_ptr->num_chunk_list<=0)
678 p=png_ptr->chunk_list+png_ptr->num_chunk_list*5-5;
679 for (i = png_ptr->num_chunk_list; i; i--, p-=5)
680 if (!png_memcmp(chunk_name, p, 4))
681 return ((int)*(p+4));
686 /* This function, added to libpng-1.0.6g, is untested. */
688 png_reset_zstream(png_structp png_ptr)
690 return (inflateReset(&png_ptr->zstream));
693 /* This function was added to libpng-1.0.7 */
695 png_access_version_number(void)
697 /* Version of *.c files used when building libpng */
698 return((png_uint_32) 10009L);
702 #if 0 /* delay this until version 1.2.0 */
703 /* this function was added to libpng 1.0.9 (porting aid to libpng-1.2.0) */
704 #ifndef PNG_ASSEMBLER_CODE_SUPPORTED
706 png_mmx_support(void)