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1 
2 /* pngread.c - read a PNG file
3  *
4  * Last changed in libpng 1.2.44 [June 26, 2010]
5  * Copyright (c) 1998-2010 Glenn Randers-Pehrson
6  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
7  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
8  *
9  * This code is released under the libpng license.
10  * For conditions of distribution and use, see the disclaimer
11  * and license in png.h
12  *
13  * This file contains routines that an application calls directly to
14  * read a PNG file or stream.
15  */
16 
17 #define PNG_INTERNAL
18 #define PNG_NO_PEDANTIC_WARNINGS
19 #include "png.h"
20 #ifdef PNG_READ_SUPPORTED
21 
22 
23 /* Create a PNG structure for reading, and allocate any memory needed. */
24 png_structp PNGAPI
png_create_read_struct(png_const_charp user_png_ver,png_voidp error_ptr,png_error_ptr error_fn,png_error_ptr warn_fn)25 png_create_read_struct(png_const_charp user_png_ver, png_voidp error_ptr,
26    png_error_ptr error_fn, png_error_ptr warn_fn)
27 {
28 
29 #ifdef PNG_USER_MEM_SUPPORTED
30    return (png_create_read_struct_2(user_png_ver, error_ptr, error_fn,
31       warn_fn, png_voidp_NULL, png_malloc_ptr_NULL, png_free_ptr_NULL));
32 }
33 
34 /* Alternate create PNG structure for reading, and allocate any memory
35  * needed.
36  */
37 png_structp PNGAPI
png_create_read_struct_2(png_const_charp user_png_ver,png_voidp error_ptr,png_error_ptr error_fn,png_error_ptr warn_fn,png_voidp mem_ptr,png_malloc_ptr malloc_fn,png_free_ptr free_fn)38 png_create_read_struct_2(png_const_charp user_png_ver, png_voidp error_ptr,
39    png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
40    png_malloc_ptr malloc_fn, png_free_ptr free_fn)
41 {
42 #endif /* PNG_USER_MEM_SUPPORTED */
43 
44 #ifdef PNG_SETJMP_SUPPORTED
45    volatile
46 #endif
47    png_structp png_ptr;
48 
49 #ifdef PNG_SETJMP_SUPPORTED
50 #ifdef USE_FAR_KEYWORD
51    jmp_buf jmpbuf;
52 #endif
53 #endif
54 
55    int i;
56 
57    png_debug(1, "in png_create_read_struct");
58 
59 #ifdef PNG_USER_MEM_SUPPORTED
60    png_ptr = (png_structp)png_create_struct_2(PNG_STRUCT_PNG,
61       (png_malloc_ptr)malloc_fn, (png_voidp)mem_ptr);
62 #else
63    png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
64 #endif
65    if (png_ptr == NULL)
66       return (NULL);
67 
68    /* Added at libpng-1.2.6 */
69 #ifdef PNG_USER_LIMITS_SUPPORTED
70    png_ptr->user_width_max = PNG_USER_WIDTH_MAX;
71    png_ptr->user_height_max = PNG_USER_HEIGHT_MAX;
72 #  ifdef PNG_USER_CHUNK_CACHE_MAX
73    /* Added at libpng-1.2.43 and 1.4.0 */
74    png_ptr->user_chunk_cache_max = PNG_USER_CHUNK_CACHE_MAX;
75 #  endif
76 #  ifdef PNG_SET_USER_CHUNK_MALLOC_MAX
77    /* Added at libpng-1.2.43 and 1.4.1 */
78    png_ptr->user_chunk_malloc_max = PNG_USER_CHUNK_MALLOC_MAX;
79 #  endif
80 #endif
81 
82 #ifdef PNG_SETJMP_SUPPORTED
83 #ifdef USE_FAR_KEYWORD
84    if (setjmp(jmpbuf))
85 #else
86    if (setjmp(png_ptr->jmpbuf))
87 #endif
88    {
89       png_free(png_ptr, png_ptr->zbuf);
90       png_ptr->zbuf = NULL;
91 #ifdef PNG_USER_MEM_SUPPORTED
92       png_destroy_struct_2((png_voidp)png_ptr,
93          (png_free_ptr)free_fn, (png_voidp)mem_ptr);
94 #else
95       png_destroy_struct((png_voidp)png_ptr);
96 #endif
97       return (NULL);
98    }
99 #ifdef USE_FAR_KEYWORD
100    png_memcpy(png_ptr->jmpbuf, jmpbuf, png_sizeof(jmp_buf));
101 #endif
102 #endif /* PNG_SETJMP_SUPPORTED */
103 
104 #ifdef PNG_USER_MEM_SUPPORTED
105    png_set_mem_fn(png_ptr, mem_ptr, malloc_fn, free_fn);
106 #endif
107 
108    png_set_error_fn(png_ptr, error_ptr, error_fn, warn_fn);
109 
110    if (user_png_ver)
111    {
112       i = 0;
113       do
114       {
115          if (user_png_ver[i] != png_libpng_ver[i])
116             png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
117       } while (png_libpng_ver[i++]);
118     }
119     else
120          png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
121 
122 
123     if (png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH)
124     {
125        /* Libpng 0.90 and later are binary incompatible with libpng 0.89, so
126        * we must recompile any applications that use any older library version.
127        * For versions after libpng 1.0, we will be compatible, so we need
128        * only check the first digit.
129        */
130       if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0] ||
131           (user_png_ver[0] == '1' && user_png_ver[2] != png_libpng_ver[2]) ||
132           (user_png_ver[0] == '0' && user_png_ver[2] < '9'))
133       {
134 #if defined(PNG_STDIO_SUPPORTED) && !defined(_WIN32_WCE)
135          char msg[80];
136          if (user_png_ver)
137          {
138            png_snprintf(msg, 80,
139               "Application was compiled with png.h from libpng-%.20s",
140               user_png_ver);
141            png_warning(png_ptr, msg);
142          }
143          png_snprintf(msg, 80,
144              "Application  is  running with png.c from libpng-%.20s",
145              png_libpng_ver);
146          png_warning(png_ptr, msg);
147 #endif
148 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
149          png_ptr->flags = 0;
150 #endif
151          png_error(png_ptr,
152             "Incompatible libpng version in application and library");
153       }
154    }
155 
156    /* Initialize zbuf - compression buffer */
157    png_ptr->zbuf_size = PNG_ZBUF_SIZE;
158    png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
159      (png_uint_32)png_ptr->zbuf_size);
160    png_ptr->zstream.zalloc = png_zalloc;
161    png_ptr->zstream.zfree = png_zfree;
162    png_ptr->zstream.opaque = (voidpf)png_ptr;
163 
164       switch (inflateInit(&png_ptr->zstream))
165       {
166          case Z_OK: /* Do nothing */ break;
167          case Z_MEM_ERROR:
168          case Z_STREAM_ERROR: png_error(png_ptr, "zlib memory error");
169             break;
170          case Z_VERSION_ERROR: png_error(png_ptr, "zlib version error");
171             break;
172          default: png_error(png_ptr, "Unknown zlib error");
173       }
174 
175 
176    png_ptr->zstream.next_out = png_ptr->zbuf;
177    png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
178 
179    png_set_read_fn(png_ptr, png_voidp_NULL, png_rw_ptr_NULL);
180 
181 #ifdef PNG_SETJMP_SUPPORTED
182 /* Applications that neglect to set up their own setjmp() and then
183    encounter a png_error() will longjmp here.  Since the jmpbuf is
184    then meaningless we abort instead of returning. */
185 #ifdef USE_FAR_KEYWORD
186    if (setjmp(jmpbuf))
187        PNG_ABORT();
188    png_memcpy(png_ptr->jmpbuf, jmpbuf, png_sizeof(jmp_buf));
189 #else
190    if (setjmp(png_ptr->jmpbuf))
191        PNG_ABORT();
192 #endif
193 #endif /* PNG_SETJMP_SUPPORTED */
194 
195    return (png_ptr);
196 }
197 
198 #if defined(PNG_1_0_X) || defined(PNG_1_2_X)
199 /* Initialize PNG structure for reading, and allocate any memory needed.
200  * This interface is deprecated in favour of the png_create_read_struct(),
201  * and it will disappear as of libpng-1.3.0.
202  */
203 #undef png_read_init
204 void PNGAPI
png_read_init(png_structp png_ptr)205 png_read_init(png_structp png_ptr)
206 {
207    /* We only come here via pre-1.0.7-compiled applications */
208    png_read_init_2(png_ptr, "1.0.6 or earlier", 0, 0);
209 }
210 
211 void PNGAPI
png_read_init_2(png_structp png_ptr,png_const_charp user_png_ver,png_size_t png_struct_size,png_size_t png_info_size)212 png_read_init_2(png_structp png_ptr, png_const_charp user_png_ver,
213    png_size_t png_struct_size, png_size_t png_info_size)
214 {
215    /* We only come here via pre-1.0.12-compiled applications */
216    if (png_ptr == NULL)
217       return;
218 #if defined(PNG_STDIO_SUPPORTED) && !defined(_WIN32_WCE)
219    if (png_sizeof(png_struct) > png_struct_size ||
220       png_sizeof(png_info) > png_info_size)
221    {
222       char msg[80];
223       png_ptr->warning_fn = NULL;
224       if (user_png_ver)
225       {
226         png_snprintf(msg, 80,
227            "Application was compiled with png.h from libpng-%.20s",
228            user_png_ver);
229         png_warning(png_ptr, msg);
230       }
231       png_snprintf(msg, 80,
232          "Application  is  running with png.c from libpng-%.20s",
233          png_libpng_ver);
234       png_warning(png_ptr, msg);
235    }
236 #endif
237    if (png_sizeof(png_struct) > png_struct_size)
238    {
239       png_ptr->error_fn = NULL;
240 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
241       png_ptr->flags = 0;
242 #endif
243       png_error(png_ptr,
244       "The png struct allocated by the application for reading is"
245       " too small.");
246    }
247    if (png_sizeof(png_info) > png_info_size)
248    {
249       png_ptr->error_fn = NULL;
250 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
251       png_ptr->flags = 0;
252 #endif
253       png_error(png_ptr,
254         "The info struct allocated by application for reading is"
255         " too small.");
256    }
257    png_read_init_3(&png_ptr, user_png_ver, png_struct_size);
258 }
259 #endif /* PNG_1_0_X || PNG_1_2_X */
260 
261 void PNGAPI
png_read_init_3(png_structpp ptr_ptr,png_const_charp user_png_ver,png_size_t png_struct_size)262 png_read_init_3(png_structpp ptr_ptr, png_const_charp user_png_ver,
263    png_size_t png_struct_size)
264 {
265 #ifdef PNG_SETJMP_SUPPORTED
266    jmp_buf tmp_jmp;  /* to save current jump buffer */
267 #endif
268 
269    int i = 0;
270 
271    png_structp png_ptr=*ptr_ptr;
272 
273    if (png_ptr == NULL)
274       return;
275 
276    do
277    {
278       if (user_png_ver[i] != png_libpng_ver[i])
279       {
280 #ifdef PNG_LEGACY_SUPPORTED
281         png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
282 #else
283         png_ptr->warning_fn = NULL;
284         png_warning(png_ptr,
285          "Application uses deprecated png_read_init() and should be"
286          " recompiled.");
287         break;
288 #endif
289       }
290    } while (png_libpng_ver[i++]);
291 
292    png_debug(1, "in png_read_init_3");
293 
294 #ifdef PNG_SETJMP_SUPPORTED
295    /* Save jump buffer and error functions */
296    png_memcpy(tmp_jmp, png_ptr->jmpbuf, png_sizeof(jmp_buf));
297 #endif
298 
299    if (png_sizeof(png_struct) > png_struct_size)
300    {
301       png_destroy_struct(png_ptr);
302       *ptr_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
303       png_ptr = *ptr_ptr;
304    }
305 
306    /* Reset all variables to 0 */
307    png_memset(png_ptr, 0, png_sizeof(png_struct));
308 
309 #ifdef PNG_SETJMP_SUPPORTED
310    /* Restore jump buffer */
311    png_memcpy(png_ptr->jmpbuf, tmp_jmp, png_sizeof(jmp_buf));
312 #endif
313 
314    /* Added at libpng-1.2.6 */
315 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
316    png_ptr->user_width_max = PNG_USER_WIDTH_MAX;
317    png_ptr->user_height_max = PNG_USER_HEIGHT_MAX;
318 #endif
319 
320    /* Initialize zbuf - compression buffer */
321    png_ptr->zbuf_size = PNG_ZBUF_SIZE;
322    png_ptr->zstream.zalloc = png_zalloc;
323    png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
324      (png_uint_32)png_ptr->zbuf_size);
325    png_ptr->zstream.zalloc = png_zalloc;
326    png_ptr->zstream.zfree = png_zfree;
327    png_ptr->zstream.opaque = (voidpf)png_ptr;
328 
329    switch (inflateInit(&png_ptr->zstream))
330    {
331       case Z_OK: /* Do nothing */ break;
332       case Z_STREAM_ERROR: png_error(png_ptr, "zlib memory error"); break;
333       case Z_VERSION_ERROR: png_error(png_ptr, "zlib version error");
334           break;
335       default: png_error(png_ptr, "Unknown zlib error");
336    }
337 
338    png_ptr->zstream.next_out = png_ptr->zbuf;
339    png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
340 
341    png_set_read_fn(png_ptr, png_voidp_NULL, png_rw_ptr_NULL);
342 }
343 
344 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
345 /* Read the information before the actual image data.  This has been
346  * changed in v0.90 to allow reading a file that already has the magic
347  * bytes read from the stream.  You can tell libpng how many bytes have
348  * been read from the beginning of the stream (up to the maximum of 8)
349  * via png_set_sig_bytes(), and we will only check the remaining bytes
350  * here.  The application can then have access to the signature bytes we
351  * read if it is determined that this isn't a valid PNG file.
352  */
353 void PNGAPI
png_read_info(png_structp png_ptr,png_infop info_ptr)354 png_read_info(png_structp png_ptr, png_infop info_ptr)
355 {
356    png_debug(1, "in png_read_info");
357 
358    if (png_ptr == NULL || info_ptr == NULL)
359       return;
360 
361    /* If we haven't checked all of the PNG signature bytes, do so now. */
362    if (png_ptr->sig_bytes < 8)
363    {
364       png_size_t num_checked = png_ptr->sig_bytes,
365                  num_to_check = 8 - num_checked;
366 
367       png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check);
368       png_ptr->sig_bytes = 8;
369 
370       if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
371       {
372          if (num_checked < 4 &&
373              png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
374             png_error(png_ptr, "Not a PNG file");
375          else
376             png_error(png_ptr, "PNG file corrupted by ASCII conversion");
377       }
378       if (num_checked < 3)
379          png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
380    }
381 
382    for (;;)
383    {
384 #ifdef PNG_USE_LOCAL_ARRAYS
385       PNG_CONST PNG_IHDR;
386       PNG_CONST PNG_IDAT;
387       PNG_CONST PNG_IEND;
388       PNG_CONST PNG_PLTE;
389 #ifdef PNG_READ_bKGD_SUPPORTED
390       PNG_CONST PNG_bKGD;
391 #endif
392 #ifdef PNG_READ_cHRM_SUPPORTED
393       PNG_CONST PNG_cHRM;
394 #endif
395 #ifdef PNG_READ_gAMA_SUPPORTED
396       PNG_CONST PNG_gAMA;
397 #endif
398 #ifdef PNG_READ_hIST_SUPPORTED
399       PNG_CONST PNG_hIST;
400 #endif
401 #ifdef PNG_READ_iCCP_SUPPORTED
402       PNG_CONST PNG_iCCP;
403 #endif
404 #ifdef PNG_READ_iTXt_SUPPORTED
405       PNG_CONST PNG_iTXt;
406 #endif
407 #ifdef PNG_READ_oFFs_SUPPORTED
408       PNG_CONST PNG_oFFs;
409 #endif
410 #ifdef PNG_READ_pCAL_SUPPORTED
411       PNG_CONST PNG_pCAL;
412 #endif
413 #ifdef PNG_READ_pHYs_SUPPORTED
414       PNG_CONST PNG_pHYs;
415 #endif
416 #ifdef PNG_READ_sBIT_SUPPORTED
417       PNG_CONST PNG_sBIT;
418 #endif
419 #ifdef PNG_READ_sCAL_SUPPORTED
420       PNG_CONST PNG_sCAL;
421 #endif
422 #ifdef PNG_READ_sPLT_SUPPORTED
423       PNG_CONST PNG_sPLT;
424 #endif
425 #ifdef PNG_READ_sRGB_SUPPORTED
426       PNG_CONST PNG_sRGB;
427 #endif
428 #ifdef PNG_READ_tEXt_SUPPORTED
429       PNG_CONST PNG_tEXt;
430 #endif
431 #ifdef PNG_READ_tIME_SUPPORTED
432       PNG_CONST PNG_tIME;
433 #endif
434 #ifdef PNG_READ_tRNS_SUPPORTED
435       PNG_CONST PNG_tRNS;
436 #endif
437 #ifdef PNG_READ_zTXt_SUPPORTED
438       PNG_CONST PNG_zTXt;
439 #endif
440 #endif /* PNG_USE_LOCAL_ARRAYS */
441       png_uint_32 length = png_read_chunk_header(png_ptr);
442       PNG_CONST png_bytep chunk_name = png_ptr->chunk_name;
443 
444       /* This should be a binary subdivision search or a hash for
445        * matching the chunk name rather than a linear search.
446        */
447       if (!png_memcmp(chunk_name, png_IDAT, 4))
448         if (png_ptr->mode & PNG_AFTER_IDAT)
449           png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
450 
451       if (!png_memcmp(chunk_name, png_IHDR, 4))
452          png_handle_IHDR(png_ptr, info_ptr, length);
453       else if (!png_memcmp(chunk_name, png_IEND, 4))
454          png_handle_IEND(png_ptr, info_ptr, length);
455 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
456       else if (png_handle_as_unknown(png_ptr, chunk_name))
457       {
458          if (!png_memcmp(chunk_name, png_IDAT, 4))
459             png_ptr->mode |= PNG_HAVE_IDAT;
460          png_handle_unknown(png_ptr, info_ptr, length);
461          if (!png_memcmp(chunk_name, png_PLTE, 4))
462             png_ptr->mode |= PNG_HAVE_PLTE;
463          else if (!png_memcmp(chunk_name, png_IDAT, 4))
464          {
465             if (!(png_ptr->mode & PNG_HAVE_IHDR))
466                png_error(png_ptr, "Missing IHDR before IDAT");
467             else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
468                      !(png_ptr->mode & PNG_HAVE_PLTE))
469                png_error(png_ptr, "Missing PLTE before IDAT");
470             break;
471          }
472       }
473 #endif
474       else if (!png_memcmp(chunk_name, png_PLTE, 4))
475          png_handle_PLTE(png_ptr, info_ptr, length);
476       else if (!png_memcmp(chunk_name, png_IDAT, 4))
477       {
478          if (!(png_ptr->mode & PNG_HAVE_IHDR))
479             png_error(png_ptr, "Missing IHDR before IDAT");
480          else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
481                   !(png_ptr->mode & PNG_HAVE_PLTE))
482             png_error(png_ptr, "Missing PLTE before IDAT");
483 
484          png_ptr->idat_size = length;
485          png_ptr->mode |= PNG_HAVE_IDAT;
486          break;
487       }
488 #ifdef PNG_READ_bKGD_SUPPORTED
489       else if (!png_memcmp(chunk_name, png_bKGD, 4))
490          png_handle_bKGD(png_ptr, info_ptr, length);
491 #endif
492 #ifdef PNG_READ_cHRM_SUPPORTED
493       else if (!png_memcmp(chunk_name, png_cHRM, 4))
494          png_handle_cHRM(png_ptr, info_ptr, length);
495 #endif
496 #ifdef PNG_READ_gAMA_SUPPORTED
497       else if (!png_memcmp(chunk_name, png_gAMA, 4))
498          png_handle_gAMA(png_ptr, info_ptr, length);
499 #endif
500 #ifdef PNG_READ_hIST_SUPPORTED
501       else if (!png_memcmp(chunk_name, png_hIST, 4))
502          png_handle_hIST(png_ptr, info_ptr, length);
503 #endif
504 #ifdef PNG_READ_oFFs_SUPPORTED
505       else if (!png_memcmp(chunk_name, png_oFFs, 4))
506          png_handle_oFFs(png_ptr, info_ptr, length);
507 #endif
508 #ifdef PNG_READ_pCAL_SUPPORTED
509       else if (!png_memcmp(chunk_name, png_pCAL, 4))
510          png_handle_pCAL(png_ptr, info_ptr, length);
511 #endif
512 #ifdef PNG_READ_sCAL_SUPPORTED
513       else if (!png_memcmp(chunk_name, png_sCAL, 4))
514          png_handle_sCAL(png_ptr, info_ptr, length);
515 #endif
516 #ifdef PNG_READ_pHYs_SUPPORTED
517       else if (!png_memcmp(chunk_name, png_pHYs, 4))
518          png_handle_pHYs(png_ptr, info_ptr, length);
519 #endif
520 #ifdef PNG_READ_sBIT_SUPPORTED
521       else if (!png_memcmp(chunk_name, png_sBIT, 4))
522          png_handle_sBIT(png_ptr, info_ptr, length);
523 #endif
524 #ifdef PNG_READ_sRGB_SUPPORTED
525       else if (!png_memcmp(chunk_name, png_sRGB, 4))
526          png_handle_sRGB(png_ptr, info_ptr, length);
527 #endif
528 #ifdef PNG_READ_iCCP_SUPPORTED
529       else if (!png_memcmp(chunk_name, png_iCCP, 4))
530          png_handle_iCCP(png_ptr, info_ptr, length);
531 #endif
532 #ifdef PNG_READ_sPLT_SUPPORTED
533       else if (!png_memcmp(chunk_name, png_sPLT, 4))
534          png_handle_sPLT(png_ptr, info_ptr, length);
535 #endif
536 #ifdef PNG_READ_tEXt_SUPPORTED
537       else if (!png_memcmp(chunk_name, png_tEXt, 4))
538          png_handle_tEXt(png_ptr, info_ptr, length);
539 #endif
540 #ifdef PNG_READ_tIME_SUPPORTED
541       else if (!png_memcmp(chunk_name, png_tIME, 4))
542          png_handle_tIME(png_ptr, info_ptr, length);
543 #endif
544 #ifdef PNG_READ_tRNS_SUPPORTED
545       else if (!png_memcmp(chunk_name, png_tRNS, 4))
546          png_handle_tRNS(png_ptr, info_ptr, length);
547 #endif
548 #ifdef PNG_READ_zTXt_SUPPORTED
549       else if (!png_memcmp(chunk_name, png_zTXt, 4))
550          png_handle_zTXt(png_ptr, info_ptr, length);
551 #endif
552 #ifdef PNG_READ_iTXt_SUPPORTED
553       else if (!png_memcmp(chunk_name, png_iTXt, 4))
554          png_handle_iTXt(png_ptr, info_ptr, length);
555 #endif
556       else
557          png_handle_unknown(png_ptr, info_ptr, length);
558    }
559 }
560 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
561 
562 /* Optional call to update the users info_ptr structure */
563 void PNGAPI
png_read_update_info(png_structp png_ptr,png_infop info_ptr)564 png_read_update_info(png_structp png_ptr, png_infop info_ptr)
565 {
566    png_debug(1, "in png_read_update_info");
567 
568    if (png_ptr == NULL)
569       return;
570    if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
571       png_read_start_row(png_ptr);
572    else
573       png_warning(png_ptr,
574       "Ignoring extra png_read_update_info() call; row buffer not reallocated");
575 
576    png_read_transform_info(png_ptr, info_ptr);
577 }
578 
579 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
580 /* Initialize palette, background, etc, after transformations
581  * are set, but before any reading takes place.  This allows
582  * the user to obtain a gamma-corrected palette, for example.
583  * If the user doesn't call this, we will do it ourselves.
584  */
585 void PNGAPI
png_start_read_image(png_structp png_ptr)586 png_start_read_image(png_structp png_ptr)
587 {
588    png_debug(1, "in png_start_read_image");
589 
590    if (png_ptr == NULL)
591       return;
592    if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
593       png_read_start_row(png_ptr);
594 }
595 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
596 
597 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
598 void PNGAPI
png_read_row(png_structp png_ptr,png_bytep row,png_bytep dsp_row)599 png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
600 {
601    PNG_CONST PNG_IDAT;
602    PNG_CONST int png_pass_dsp_mask[7] = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55,
603       0xff};
604    PNG_CONST int png_pass_mask[7] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
605    int ret;
606 
607    if (png_ptr == NULL)
608       return;
609 
610    png_debug2(1, "in png_read_row (row %lu, pass %d)",
611       png_ptr->row_number, png_ptr->pass);
612 
613    if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
614       png_read_start_row(png_ptr);
615    if (png_ptr->row_number == 0 && png_ptr->pass == 0)
616    {
617    /* Check for transforms that have been set but were defined out */
618 #if defined(PNG_WRITE_INVERT_SUPPORTED) && !defined(PNG_READ_INVERT_SUPPORTED)
619    if (png_ptr->transformations & PNG_INVERT_MONO)
620       png_warning(png_ptr, "PNG_READ_INVERT_SUPPORTED is not defined.");
621 #endif
622 #if defined(PNG_WRITE_FILLER_SUPPORTED) && !defined(PNG_READ_FILLER_SUPPORTED)
623    if (png_ptr->transformations & PNG_FILLER)
624       png_warning(png_ptr, "PNG_READ_FILLER_SUPPORTED is not defined.");
625 #endif
626 #if defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
627     !defined(PNG_READ_PACKSWAP_SUPPORTED)
628    if (png_ptr->transformations & PNG_PACKSWAP)
629       png_warning(png_ptr, "PNG_READ_PACKSWAP_SUPPORTED is not defined.");
630 #endif
631 #if defined(PNG_WRITE_PACK_SUPPORTED) && !defined(PNG_READ_PACK_SUPPORTED)
632    if (png_ptr->transformations & PNG_PACK)
633       png_warning(png_ptr, "PNG_READ_PACK_SUPPORTED is not defined.");
634 #endif
635 #if defined(PNG_WRITE_SHIFT_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED)
636    if (png_ptr->transformations & PNG_SHIFT)
637       png_warning(png_ptr, "PNG_READ_SHIFT_SUPPORTED is not defined.");
638 #endif
639 #if defined(PNG_WRITE_BGR_SUPPORTED) && !defined(PNG_READ_BGR_SUPPORTED)
640    if (png_ptr->transformations & PNG_BGR)
641       png_warning(png_ptr, "PNG_READ_BGR_SUPPORTED is not defined.");
642 #endif
643 #if defined(PNG_WRITE_SWAP_SUPPORTED) && !defined(PNG_READ_SWAP_SUPPORTED)
644    if (png_ptr->transformations & PNG_SWAP_BYTES)
645       png_warning(png_ptr, "PNG_READ_SWAP_SUPPORTED is not defined.");
646 #endif
647    }
648 
649 #ifdef PNG_READ_INTERLACING_SUPPORTED
650    /* If interlaced and we do not need a new row, combine row and return */
651    if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
652    {
653       switch (png_ptr->pass)
654       {
655          case 0:
656             if (png_ptr->row_number & 0x07)
657             {
658                if (dsp_row != NULL)
659                   png_combine_row(png_ptr, dsp_row,
660                      png_pass_dsp_mask[png_ptr->pass]);
661                png_read_finish_row(png_ptr);
662                return;
663             }
664             break;
665          case 1:
666             if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
667             {
668                if (dsp_row != NULL)
669                   png_combine_row(png_ptr, dsp_row,
670                      png_pass_dsp_mask[png_ptr->pass]);
671                png_read_finish_row(png_ptr);
672                return;
673             }
674             break;
675          case 2:
676             if ((png_ptr->row_number & 0x07) != 4)
677             {
678                if (dsp_row != NULL && (png_ptr->row_number & 4))
679                   png_combine_row(png_ptr, dsp_row,
680                      png_pass_dsp_mask[png_ptr->pass]);
681                png_read_finish_row(png_ptr);
682                return;
683             }
684             break;
685          case 3:
686             if ((png_ptr->row_number & 3) || png_ptr->width < 3)
687             {
688                if (dsp_row != NULL)
689                   png_combine_row(png_ptr, dsp_row,
690                      png_pass_dsp_mask[png_ptr->pass]);
691                png_read_finish_row(png_ptr);
692                return;
693             }
694             break;
695          case 4:
696             if ((png_ptr->row_number & 3) != 2)
697             {
698                if (dsp_row != NULL && (png_ptr->row_number & 2))
699                   png_combine_row(png_ptr, dsp_row,
700                      png_pass_dsp_mask[png_ptr->pass]);
701                png_read_finish_row(png_ptr);
702                return;
703             }
704             break;
705          case 5:
706             if ((png_ptr->row_number & 1) || png_ptr->width < 2)
707             {
708                if (dsp_row != NULL)
709                   png_combine_row(png_ptr, dsp_row,
710                      png_pass_dsp_mask[png_ptr->pass]);
711                png_read_finish_row(png_ptr);
712                return;
713             }
714             break;
715          case 6:
716             if (!(png_ptr->row_number & 1))
717             {
718                png_read_finish_row(png_ptr);
719                return;
720             }
721             break;
722       }
723    }
724 #endif
725 
726    if (!(png_ptr->mode & PNG_HAVE_IDAT))
727       png_error(png_ptr, "Invalid attempt to read row data");
728 
729    png_ptr->zstream.next_out = png_ptr->row_buf;
730    png_ptr->zstream.avail_out =
731        (uInt)(PNG_ROWBYTES(png_ptr->pixel_depth,
732        png_ptr->iwidth) + 1);
733    do
734    {
735       if (!(png_ptr->zstream.avail_in))
736       {
737          while (!png_ptr->idat_size)
738          {
739             png_crc_finish(png_ptr, 0);
740 
741             png_ptr->idat_size = png_read_chunk_header(png_ptr);
742             if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
743                png_error(png_ptr, "Not enough image data");
744          }
745          png_ptr->zstream.avail_in = (uInt)png_ptr->zbuf_size;
746          png_ptr->zstream.next_in = png_ptr->zbuf;
747          if (png_ptr->zbuf_size > png_ptr->idat_size)
748             png_ptr->zstream.avail_in = (uInt)png_ptr->idat_size;
749          png_crc_read(png_ptr, png_ptr->zbuf,
750             (png_size_t)png_ptr->zstream.avail_in);
751          png_ptr->idat_size -= png_ptr->zstream.avail_in;
752       }
753       ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
754       if (ret == Z_STREAM_END)
755       {
756          if (png_ptr->zstream.avail_out || png_ptr->zstream.avail_in ||
757             png_ptr->idat_size)
758             png_error(png_ptr, "Extra compressed data");
759          png_ptr->mode |= PNG_AFTER_IDAT;
760          png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
761          break;
762       }
763       if (ret != Z_OK)
764          png_error(png_ptr, png_ptr->zstream.msg ? png_ptr->zstream.msg :
765                    "Decompression error");
766 
767    } while (png_ptr->zstream.avail_out);
768 
769    png_ptr->row_info.color_type = png_ptr->color_type;
770    png_ptr->row_info.width = png_ptr->iwidth;
771    png_ptr->row_info.channels = png_ptr->channels;
772    png_ptr->row_info.bit_depth = png_ptr->bit_depth;
773    png_ptr->row_info.pixel_depth = png_ptr->pixel_depth;
774    png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
775        png_ptr->row_info.width);
776 
777    if (png_ptr->row_buf[0])
778    png_read_filter_row(png_ptr, &(png_ptr->row_info),
779       png_ptr->row_buf + 1, png_ptr->prev_row + 1,
780       (int)(png_ptr->row_buf[0]));
781 
782    png_memcpy_check(png_ptr, png_ptr->prev_row, png_ptr->row_buf,
783       png_ptr->rowbytes + 1);
784 
785 #ifdef PNG_MNG_FEATURES_SUPPORTED
786    if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
787       (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
788    {
789       /* Intrapixel differencing */
790       png_do_read_intrapixel(&(png_ptr->row_info), png_ptr->row_buf + 1);
791    }
792 #endif
793 
794 
795    if (png_ptr->transformations || (png_ptr->flags&PNG_FLAG_STRIP_ALPHA))
796       png_do_read_transformations(png_ptr);
797 
798 #ifdef PNG_READ_INTERLACING_SUPPORTED
799    /* Blow up interlaced rows to full size */
800    if (png_ptr->interlaced &&
801       (png_ptr->transformations & PNG_INTERLACE))
802    {
803       if (png_ptr->pass < 6)
804          /* Old interface (pre-1.0.9):
805           * png_do_read_interlace(&(png_ptr->row_info),
806           *    png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations);
807           */
808          png_do_read_interlace(png_ptr);
809 
810       if (dsp_row != NULL)
811          png_combine_row(png_ptr, dsp_row,
812             png_pass_dsp_mask[png_ptr->pass]);
813       if (row != NULL)
814          png_combine_row(png_ptr, row,
815             png_pass_mask[png_ptr->pass]);
816    }
817    else
818 #endif
819    {
820       if (row != NULL)
821          png_combine_row(png_ptr, row, 0xff);
822       if (dsp_row != NULL)
823          png_combine_row(png_ptr, dsp_row, 0xff);
824    }
825    png_read_finish_row(png_ptr);
826 
827    if (png_ptr->read_row_fn != NULL)
828       (*(png_ptr->read_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
829 }
830 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
831 
832 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
833 /* Read one or more rows of image data.  If the image is interlaced,
834  * and png_set_interlace_handling() has been called, the rows need to
835  * contain the contents of the rows from the previous pass.  If the
836  * image has alpha or transparency, and png_handle_alpha()[*] has been
837  * called, the rows contents must be initialized to the contents of the
838  * screen.
839  *
840  * "row" holds the actual image, and pixels are placed in it
841  * as they arrive.  If the image is displayed after each pass, it will
842  * appear to "sparkle" in.  "display_row" can be used to display a
843  * "chunky" progressive image, with finer detail added as it becomes
844  * available.  If you do not want this "chunky" display, you may pass
845  * NULL for display_row.  If you do not want the sparkle display, and
846  * you have not called png_handle_alpha(), you may pass NULL for rows.
847  * If you have called png_handle_alpha(), and the image has either an
848  * alpha channel or a transparency chunk, you must provide a buffer for
849  * rows.  In this case, you do not have to provide a display_row buffer
850  * also, but you may.  If the image is not interlaced, or if you have
851  * not called png_set_interlace_handling(), the display_row buffer will
852  * be ignored, so pass NULL to it.
853  *
854  * [*] png_handle_alpha() does not exist yet, as of this version of libpng
855  */
856 
857 void PNGAPI
png_read_rows(png_structp png_ptr,png_bytepp row,png_bytepp display_row,png_uint_32 num_rows)858 png_read_rows(png_structp png_ptr, png_bytepp row,
859    png_bytepp display_row, png_uint_32 num_rows)
860 {
861    png_uint_32 i;
862    png_bytepp rp;
863    png_bytepp dp;
864 
865    png_debug(1, "in png_read_rows");
866 
867    if (png_ptr == NULL)
868       return;
869    rp = row;
870    dp = display_row;
871    if (rp != NULL && dp != NULL)
872       for (i = 0; i < num_rows; i++)
873       {
874          png_bytep rptr = *rp++;
875          png_bytep dptr = *dp++;
876 
877          png_read_row(png_ptr, rptr, dptr);
878       }
879    else if (rp != NULL)
880       for (i = 0; i < num_rows; i++)
881       {
882          png_bytep rptr = *rp;
883          png_read_row(png_ptr, rptr, png_bytep_NULL);
884          rp++;
885       }
886    else if (dp != NULL)
887       for (i = 0; i < num_rows; i++)
888       {
889          png_bytep dptr = *dp;
890          png_read_row(png_ptr, png_bytep_NULL, dptr);
891          dp++;
892       }
893 }
894 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
895 
896 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
897 /* Read the entire image.  If the image has an alpha channel or a tRNS
898  * chunk, and you have called png_handle_alpha()[*], you will need to
899  * initialize the image to the current image that PNG will be overlaying.
900  * We set the num_rows again here, in case it was incorrectly set in
901  * png_read_start_row() by a call to png_read_update_info() or
902  * png_start_read_image() if png_set_interlace_handling() wasn't called
903  * prior to either of these functions like it should have been.  You can
904  * only call this function once.  If you desire to have an image for
905  * each pass of a interlaced image, use png_read_rows() instead.
906  *
907  * [*] png_handle_alpha() does not exist yet, as of this version of libpng
908  */
909 void PNGAPI
png_read_image(png_structp png_ptr,png_bytepp image)910 png_read_image(png_structp png_ptr, png_bytepp image)
911 {
912    png_uint_32 i, image_height;
913    int pass, j;
914    png_bytepp rp;
915 
916    png_debug(1, "in png_read_image");
917 
918    if (png_ptr == NULL)
919       return;
920 
921 #ifdef PNG_READ_INTERLACING_SUPPORTED
922    pass = png_set_interlace_handling(png_ptr);
923 #else
924    if (png_ptr->interlaced)
925       png_error(png_ptr,
926         "Cannot read interlaced image -- interlace handler disabled.");
927    pass = 1;
928 #endif
929 
930 
931    image_height=png_ptr->height;
932    png_ptr->num_rows = image_height; /* Make sure this is set correctly */
933 
934    for (j = 0; j < pass; j++)
935    {
936       rp = image;
937       for (i = 0; i < image_height; i++)
938       {
939          png_read_row(png_ptr, *rp, png_bytep_NULL);
940          rp++;
941       }
942    }
943 }
944 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
945 
946 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
947 /* Read the end of the PNG file.  Will not read past the end of the
948  * file, will verify the end is accurate, and will read any comments
949  * or time information at the end of the file, if info is not NULL.
950  */
951 void PNGAPI
png_read_end(png_structp png_ptr,png_infop info_ptr)952 png_read_end(png_structp png_ptr, png_infop info_ptr)
953 {
954    png_debug(1, "in png_read_end");
955 
956    if (png_ptr == NULL)
957       return;
958    png_crc_finish(png_ptr, 0); /* Finish off CRC from last IDAT chunk */
959 
960    do
961    {
962 #ifdef PNG_USE_LOCAL_ARRAYS
963       PNG_CONST PNG_IHDR;
964       PNG_CONST PNG_IDAT;
965       PNG_CONST PNG_IEND;
966       PNG_CONST PNG_PLTE;
967 #ifdef PNG_READ_bKGD_SUPPORTED
968       PNG_CONST PNG_bKGD;
969 #endif
970 #ifdef PNG_READ_cHRM_SUPPORTED
971       PNG_CONST PNG_cHRM;
972 #endif
973 #ifdef PNG_READ_gAMA_SUPPORTED
974       PNG_CONST PNG_gAMA;
975 #endif
976 #ifdef PNG_READ_hIST_SUPPORTED
977       PNG_CONST PNG_hIST;
978 #endif
979 #ifdef PNG_READ_iCCP_SUPPORTED
980       PNG_CONST PNG_iCCP;
981 #endif
982 #ifdef PNG_READ_iTXt_SUPPORTED
983       PNG_CONST PNG_iTXt;
984 #endif
985 #ifdef PNG_READ_oFFs_SUPPORTED
986       PNG_CONST PNG_oFFs;
987 #endif
988 #ifdef PNG_READ_pCAL_SUPPORTED
989       PNG_CONST PNG_pCAL;
990 #endif
991 #ifdef PNG_READ_pHYs_SUPPORTED
992       PNG_CONST PNG_pHYs;
993 #endif
994 #ifdef PNG_READ_sBIT_SUPPORTED
995       PNG_CONST PNG_sBIT;
996 #endif
997 #ifdef PNG_READ_sCAL_SUPPORTED
998       PNG_CONST PNG_sCAL;
999 #endif
1000 #ifdef PNG_READ_sPLT_SUPPORTED
1001       PNG_CONST PNG_sPLT;
1002 #endif
1003 #ifdef PNG_READ_sRGB_SUPPORTED
1004       PNG_CONST PNG_sRGB;
1005 #endif
1006 #ifdef PNG_READ_tEXt_SUPPORTED
1007       PNG_CONST PNG_tEXt;
1008 #endif
1009 #ifdef PNG_READ_tIME_SUPPORTED
1010       PNG_CONST PNG_tIME;
1011 #endif
1012 #ifdef PNG_READ_tRNS_SUPPORTED
1013       PNG_CONST PNG_tRNS;
1014 #endif
1015 #ifdef PNG_READ_zTXt_SUPPORTED
1016       PNG_CONST PNG_zTXt;
1017 #endif
1018 #endif /* PNG_USE_LOCAL_ARRAYS */
1019       png_uint_32 length = png_read_chunk_header(png_ptr);
1020       PNG_CONST png_bytep chunk_name = png_ptr->chunk_name;
1021 
1022       if (!png_memcmp(chunk_name, png_IHDR, 4))
1023          png_handle_IHDR(png_ptr, info_ptr, length);
1024       else if (!png_memcmp(chunk_name, png_IEND, 4))
1025          png_handle_IEND(png_ptr, info_ptr, length);
1026 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
1027       else if (png_handle_as_unknown(png_ptr, chunk_name))
1028       {
1029          if (!png_memcmp(chunk_name, png_IDAT, 4))
1030          {
1031             if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
1032                png_error(png_ptr, "Too many IDAT's found");
1033          }
1034          png_handle_unknown(png_ptr, info_ptr, length);
1035          if (!png_memcmp(chunk_name, png_PLTE, 4))
1036             png_ptr->mode |= PNG_HAVE_PLTE;
1037       }
1038 #endif
1039       else if (!png_memcmp(chunk_name, png_IDAT, 4))
1040       {
1041          /* Zero length IDATs are legal after the last IDAT has been
1042           * read, but not after other chunks have been read.
1043           */
1044          if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
1045             png_error(png_ptr, "Too many IDAT's found");
1046          png_crc_finish(png_ptr, length);
1047       }
1048       else if (!png_memcmp(chunk_name, png_PLTE, 4))
1049          png_handle_PLTE(png_ptr, info_ptr, length);
1050 #ifdef PNG_READ_bKGD_SUPPORTED
1051       else if (!png_memcmp(chunk_name, png_bKGD, 4))
1052          png_handle_bKGD(png_ptr, info_ptr, length);
1053 #endif
1054 #ifdef PNG_READ_cHRM_SUPPORTED
1055       else if (!png_memcmp(chunk_name, png_cHRM, 4))
1056          png_handle_cHRM(png_ptr, info_ptr, length);
1057 #endif
1058 #ifdef PNG_READ_gAMA_SUPPORTED
1059       else if (!png_memcmp(chunk_name, png_gAMA, 4))
1060          png_handle_gAMA(png_ptr, info_ptr, length);
1061 #endif
1062 #ifdef PNG_READ_hIST_SUPPORTED
1063       else if (!png_memcmp(chunk_name, png_hIST, 4))
1064          png_handle_hIST(png_ptr, info_ptr, length);
1065 #endif
1066 #ifdef PNG_READ_oFFs_SUPPORTED
1067       else if (!png_memcmp(chunk_name, png_oFFs, 4))
1068          png_handle_oFFs(png_ptr, info_ptr, length);
1069 #endif
1070 #ifdef PNG_READ_pCAL_SUPPORTED
1071       else if (!png_memcmp(chunk_name, png_pCAL, 4))
1072          png_handle_pCAL(png_ptr, info_ptr, length);
1073 #endif
1074 #ifdef PNG_READ_sCAL_SUPPORTED
1075       else if (!png_memcmp(chunk_name, png_sCAL, 4))
1076          png_handle_sCAL(png_ptr, info_ptr, length);
1077 #endif
1078 #ifdef PNG_READ_pHYs_SUPPORTED
1079       else if (!png_memcmp(chunk_name, png_pHYs, 4))
1080          png_handle_pHYs(png_ptr, info_ptr, length);
1081 #endif
1082 #ifdef PNG_READ_sBIT_SUPPORTED
1083       else if (!png_memcmp(chunk_name, png_sBIT, 4))
1084          png_handle_sBIT(png_ptr, info_ptr, length);
1085 #endif
1086 #ifdef PNG_READ_sRGB_SUPPORTED
1087       else if (!png_memcmp(chunk_name, png_sRGB, 4))
1088          png_handle_sRGB(png_ptr, info_ptr, length);
1089 #endif
1090 #ifdef PNG_READ_iCCP_SUPPORTED
1091       else if (!png_memcmp(chunk_name, png_iCCP, 4))
1092          png_handle_iCCP(png_ptr, info_ptr, length);
1093 #endif
1094 #ifdef PNG_READ_sPLT_SUPPORTED
1095       else if (!png_memcmp(chunk_name, png_sPLT, 4))
1096          png_handle_sPLT(png_ptr, info_ptr, length);
1097 #endif
1098 #ifdef PNG_READ_tEXt_SUPPORTED
1099       else if (!png_memcmp(chunk_name, png_tEXt, 4))
1100          png_handle_tEXt(png_ptr, info_ptr, length);
1101 #endif
1102 #ifdef PNG_READ_tIME_SUPPORTED
1103       else if (!png_memcmp(chunk_name, png_tIME, 4))
1104          png_handle_tIME(png_ptr, info_ptr, length);
1105 #endif
1106 #ifdef PNG_READ_tRNS_SUPPORTED
1107       else if (!png_memcmp(chunk_name, png_tRNS, 4))
1108          png_handle_tRNS(png_ptr, info_ptr, length);
1109 #endif
1110 #ifdef PNG_READ_zTXt_SUPPORTED
1111       else if (!png_memcmp(chunk_name, png_zTXt, 4))
1112          png_handle_zTXt(png_ptr, info_ptr, length);
1113 #endif
1114 #ifdef PNG_READ_iTXt_SUPPORTED
1115       else if (!png_memcmp(chunk_name, png_iTXt, 4))
1116          png_handle_iTXt(png_ptr, info_ptr, length);
1117 #endif
1118       else
1119          png_handle_unknown(png_ptr, info_ptr, length);
1120    } while (!(png_ptr->mode & PNG_HAVE_IEND));
1121 }
1122 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
1123 
1124 /* Free all memory used by the read */
1125 void PNGAPI
png_destroy_read_struct(png_structpp png_ptr_ptr,png_infopp info_ptr_ptr,png_infopp end_info_ptr_ptr)1126 png_destroy_read_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr,
1127    png_infopp end_info_ptr_ptr)
1128 {
1129    png_structp png_ptr = NULL;
1130    png_infop info_ptr = NULL, end_info_ptr = NULL;
1131 #ifdef PNG_USER_MEM_SUPPORTED
1132    png_free_ptr free_fn = NULL;
1133    png_voidp mem_ptr = NULL;
1134 #endif
1135 
1136    png_debug(1, "in png_destroy_read_struct");
1137 
1138    if (png_ptr_ptr != NULL)
1139       png_ptr = *png_ptr_ptr;
1140    if (png_ptr == NULL)
1141       return;
1142 
1143 #ifdef PNG_USER_MEM_SUPPORTED
1144    free_fn = png_ptr->free_fn;
1145    mem_ptr = png_ptr->mem_ptr;
1146 #endif
1147 
1148    if (info_ptr_ptr != NULL)
1149       info_ptr = *info_ptr_ptr;
1150 
1151    if (end_info_ptr_ptr != NULL)
1152       end_info_ptr = *end_info_ptr_ptr;
1153 
1154    png_read_destroy(png_ptr, info_ptr, end_info_ptr);
1155 
1156    if (info_ptr != NULL)
1157    {
1158 #ifdef PNG_TEXT_SUPPORTED
1159       png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, -1);
1160 #endif
1161 
1162 #ifdef PNG_USER_MEM_SUPPORTED
1163       png_destroy_struct_2((png_voidp)info_ptr, (png_free_ptr)free_fn,
1164           (png_voidp)mem_ptr);
1165 #else
1166       png_destroy_struct((png_voidp)info_ptr);
1167 #endif
1168       *info_ptr_ptr = NULL;
1169    }
1170 
1171    if (end_info_ptr != NULL)
1172    {
1173 #ifdef PNG_READ_TEXT_SUPPORTED
1174       png_free_data(png_ptr, end_info_ptr, PNG_FREE_TEXT, -1);
1175 #endif
1176 #ifdef PNG_USER_MEM_SUPPORTED
1177       png_destroy_struct_2((png_voidp)end_info_ptr, (png_free_ptr)free_fn,
1178          (png_voidp)mem_ptr);
1179 #else
1180       png_destroy_struct((png_voidp)end_info_ptr);
1181 #endif
1182       *end_info_ptr_ptr = NULL;
1183    }
1184 
1185    if (png_ptr != NULL)
1186    {
1187 #ifdef PNG_USER_MEM_SUPPORTED
1188       png_destroy_struct_2((png_voidp)png_ptr, (png_free_ptr)free_fn,
1189           (png_voidp)mem_ptr);
1190 #else
1191       png_destroy_struct((png_voidp)png_ptr);
1192 #endif
1193       *png_ptr_ptr = NULL;
1194    }
1195 }
1196 
1197 /* Free all memory used by the read (old method) */
1198 void /* PRIVATE */
png_read_destroy(png_structp png_ptr,png_infop info_ptr,png_infop end_info_ptr)1199 png_read_destroy(png_structp png_ptr, png_infop info_ptr,
1200     png_infop end_info_ptr)
1201 {
1202 #ifdef PNG_SETJMP_SUPPORTED
1203    jmp_buf tmp_jmp;
1204 #endif
1205    png_error_ptr error_fn;
1206    png_error_ptr warning_fn;
1207    png_voidp error_ptr;
1208 #ifdef PNG_USER_MEM_SUPPORTED
1209    png_free_ptr free_fn;
1210 #endif
1211 
1212    png_debug(1, "in png_read_destroy");
1213 
1214    if (info_ptr != NULL)
1215       png_info_destroy(png_ptr, info_ptr);
1216 
1217    if (end_info_ptr != NULL)
1218       png_info_destroy(png_ptr, end_info_ptr);
1219 
1220    png_free(png_ptr, png_ptr->zbuf);
1221    png_free(png_ptr, png_ptr->big_row_buf);
1222    png_free(png_ptr, png_ptr->prev_row);
1223    png_free(png_ptr, png_ptr->chunkdata);
1224 #ifdef PNG_READ_DITHER_SUPPORTED
1225    png_free(png_ptr, png_ptr->palette_lookup);
1226    png_free(png_ptr, png_ptr->dither_index);
1227 #endif
1228 #ifdef PNG_READ_GAMMA_SUPPORTED
1229    png_free(png_ptr, png_ptr->gamma_table);
1230 #endif
1231 #ifdef PNG_READ_BACKGROUND_SUPPORTED
1232    png_free(png_ptr, png_ptr->gamma_from_1);
1233    png_free(png_ptr, png_ptr->gamma_to_1);
1234 #endif
1235 #ifdef PNG_FREE_ME_SUPPORTED
1236    if (png_ptr->free_me & PNG_FREE_PLTE)
1237       png_zfree(png_ptr, png_ptr->palette);
1238    png_ptr->free_me &= ~PNG_FREE_PLTE;
1239 #else
1240    if (png_ptr->flags & PNG_FLAG_FREE_PLTE)
1241       png_zfree(png_ptr, png_ptr->palette);
1242    png_ptr->flags &= ~PNG_FLAG_FREE_PLTE;
1243 #endif
1244 #if defined(PNG_tRNS_SUPPORTED) || \
1245     defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
1246 #ifdef PNG_FREE_ME_SUPPORTED
1247    if (png_ptr->free_me & PNG_FREE_TRNS)
1248       png_free(png_ptr, png_ptr->trans);
1249    png_ptr->free_me &= ~PNG_FREE_TRNS;
1250 #else
1251    if (png_ptr->flags & PNG_FLAG_FREE_TRNS)
1252       png_free(png_ptr, png_ptr->trans);
1253    png_ptr->flags &= ~PNG_FLAG_FREE_TRNS;
1254 #endif
1255 #endif
1256 #ifdef PNG_READ_hIST_SUPPORTED
1257 #ifdef PNG_FREE_ME_SUPPORTED
1258    if (png_ptr->free_me & PNG_FREE_HIST)
1259       png_free(png_ptr, png_ptr->hist);
1260    png_ptr->free_me &= ~PNG_FREE_HIST;
1261 #else
1262    if (png_ptr->flags & PNG_FLAG_FREE_HIST)
1263       png_free(png_ptr, png_ptr->hist);
1264    png_ptr->flags &= ~PNG_FLAG_FREE_HIST;
1265 #endif
1266 #endif
1267 #ifdef PNG_READ_GAMMA_SUPPORTED
1268    if (png_ptr->gamma_16_table != NULL)
1269    {
1270       int i;
1271       int istop = (1 << (8 - png_ptr->gamma_shift));
1272       for (i = 0; i < istop; i++)
1273       {
1274          png_free(png_ptr, png_ptr->gamma_16_table[i]);
1275       }
1276    png_free(png_ptr, png_ptr->gamma_16_table);
1277    }
1278 #ifdef PNG_READ_BACKGROUND_SUPPORTED
1279    if (png_ptr->gamma_16_from_1 != NULL)
1280    {
1281       int i;
1282       int istop = (1 << (8 - png_ptr->gamma_shift));
1283       for (i = 0; i < istop; i++)
1284       {
1285          png_free(png_ptr, png_ptr->gamma_16_from_1[i]);
1286       }
1287    png_free(png_ptr, png_ptr->gamma_16_from_1);
1288    }
1289    if (png_ptr->gamma_16_to_1 != NULL)
1290    {
1291       int i;
1292       int istop = (1 << (8 - png_ptr->gamma_shift));
1293       for (i = 0; i < istop; i++)
1294       {
1295          png_free(png_ptr, png_ptr->gamma_16_to_1[i]);
1296       }
1297    png_free(png_ptr, png_ptr->gamma_16_to_1);
1298    }
1299 #endif
1300 #endif
1301 #ifdef PNG_TIME_RFC1123_SUPPORTED
1302    png_free(png_ptr, png_ptr->time_buffer);
1303 #endif
1304 
1305    inflateEnd(&png_ptr->zstream);
1306 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1307    png_free(png_ptr, png_ptr->save_buffer);
1308 #endif
1309 
1310 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1311 #ifdef PNG_TEXT_SUPPORTED
1312    png_free(png_ptr, png_ptr->current_text);
1313 #endif /* PNG_TEXT_SUPPORTED */
1314 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
1315 
1316    /* Save the important info out of the png_struct, in case it is
1317     * being used again.
1318     */
1319 #ifdef PNG_SETJMP_SUPPORTED
1320    png_memcpy(tmp_jmp, png_ptr->jmpbuf, png_sizeof(jmp_buf));
1321 #endif
1322 
1323    error_fn = png_ptr->error_fn;
1324    warning_fn = png_ptr->warning_fn;
1325    error_ptr = png_ptr->error_ptr;
1326 #ifdef PNG_USER_MEM_SUPPORTED
1327    free_fn = png_ptr->free_fn;
1328 #endif
1329 
1330    png_memset(png_ptr, 0, png_sizeof(png_struct));
1331 
1332    png_ptr->error_fn = error_fn;
1333    png_ptr->warning_fn = warning_fn;
1334    png_ptr->error_ptr = error_ptr;
1335 #ifdef PNG_USER_MEM_SUPPORTED
1336    png_ptr->free_fn = free_fn;
1337 #endif
1338 
1339 #ifdef PNG_SETJMP_SUPPORTED
1340    png_memcpy(png_ptr->jmpbuf, tmp_jmp, png_sizeof(jmp_buf));
1341 #endif
1342 
1343 }
1344 
1345 void PNGAPI
png_set_read_status_fn(png_structp png_ptr,png_read_status_ptr read_row_fn)1346 png_set_read_status_fn(png_structp png_ptr, png_read_status_ptr read_row_fn)
1347 {
1348    if (png_ptr == NULL)
1349       return;
1350    png_ptr->read_row_fn = read_row_fn;
1351 }
1352 
1353 
1354 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1355 #ifdef PNG_INFO_IMAGE_SUPPORTED
1356 void PNGAPI
png_read_png(png_structp png_ptr,png_infop info_ptr,int transforms,voidp params)1357 png_read_png(png_structp png_ptr, png_infop info_ptr,
1358                            int transforms,
1359                            voidp params)
1360 {
1361    int row;
1362 
1363    if (png_ptr == NULL)
1364       return;
1365 #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
1366    /* Invert the alpha channel from opacity to transparency
1367     */
1368    if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
1369        png_set_invert_alpha(png_ptr);
1370 #endif
1371 
1372    /* png_read_info() gives us all of the information from the
1373     * PNG file before the first IDAT (image data chunk).
1374     */
1375    png_read_info(png_ptr, info_ptr);
1376    if (info_ptr->height > PNG_UINT_32_MAX/png_sizeof(png_bytep))
1377       png_error(png_ptr, "Image is too high to process with png_read_png()");
1378 
1379    /* -------------- image transformations start here ------------------- */
1380 
1381 #ifdef PNG_READ_16_TO_8_SUPPORTED
1382    /* Tell libpng to strip 16 bit/color files down to 8 bits per color.
1383     */
1384    if (transforms & PNG_TRANSFORM_STRIP_16)
1385       png_set_strip_16(png_ptr);
1386 #endif
1387 
1388 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
1389    /* Strip alpha bytes from the input data without combining with
1390     * the background (not recommended).
1391     */
1392    if (transforms & PNG_TRANSFORM_STRIP_ALPHA)
1393       png_set_strip_alpha(png_ptr);
1394 #endif
1395 
1396 #if defined(PNG_READ_PACK_SUPPORTED) && !defined(PNG_READ_EXPAND_SUPPORTED)
1397    /* Extract multiple pixels with bit depths of 1, 2, or 4 from a single
1398     * byte into separate bytes (useful for paletted and grayscale images).
1399     */
1400    if (transforms & PNG_TRANSFORM_PACKING)
1401       png_set_packing(png_ptr);
1402 #endif
1403 
1404 #ifdef PNG_READ_PACKSWAP_SUPPORTED
1405    /* Change the order of packed pixels to least significant bit first
1406     * (not useful if you are using png_set_packing).
1407     */
1408    if (transforms & PNG_TRANSFORM_PACKSWAP)
1409       png_set_packswap(png_ptr);
1410 #endif
1411 
1412 #ifdef PNG_READ_EXPAND_SUPPORTED
1413    /* Expand paletted colors into true RGB triplets
1414     * Expand grayscale images to full 8 bits from 1, 2, or 4 bits/pixel
1415     * Expand paletted or RGB images with transparency to full alpha
1416     * channels so the data will be available as RGBA quartets.
1417     */
1418    if (transforms & PNG_TRANSFORM_EXPAND)
1419       if ((png_ptr->bit_depth < 8) ||
1420           (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ||
1421           (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)))
1422          png_set_expand(png_ptr);
1423 #endif
1424 
1425    /* We don't handle background color or gamma transformation or dithering.
1426     */
1427 
1428 #ifdef PNG_READ_INVERT_SUPPORTED
1429    /* Invert monochrome files to have 0 as white and 1 as black
1430     */
1431    if (transforms & PNG_TRANSFORM_INVERT_MONO)
1432       png_set_invert_mono(png_ptr);
1433 #endif
1434 
1435 #ifdef PNG_READ_SHIFT_SUPPORTED
1436    /* If you want to shift the pixel values from the range [0,255] or
1437     * [0,65535] to the original [0,7] or [0,31], or whatever range the
1438     * colors were originally in:
1439     */
1440    if ((transforms & PNG_TRANSFORM_SHIFT)
1441        && png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT))
1442    {
1443       png_color_8p sig_bit;
1444 
1445       png_get_sBIT(png_ptr, info_ptr, &sig_bit);
1446       png_set_shift(png_ptr, sig_bit);
1447    }
1448 #endif
1449 
1450 #ifdef PNG_READ_BGR_SUPPORTED
1451    /* Flip the RGB pixels to BGR (or RGBA to BGRA)
1452     */
1453    if (transforms & PNG_TRANSFORM_BGR)
1454       png_set_bgr(png_ptr);
1455 #endif
1456 
1457 #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
1458    /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR)
1459     */
1460    if (transforms & PNG_TRANSFORM_SWAP_ALPHA)
1461        png_set_swap_alpha(png_ptr);
1462 #endif
1463 
1464 #ifdef PNG_READ_SWAP_SUPPORTED
1465    /* Swap bytes of 16 bit files to least significant byte first
1466     */
1467    if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
1468       png_set_swap(png_ptr);
1469 #endif
1470 
1471 /* Added at libpng-1.2.41 */
1472 #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
1473    /* Invert the alpha channel from opacity to transparency
1474     */
1475    if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
1476        png_set_invert_alpha(png_ptr);
1477 #endif
1478 
1479 /* Added at libpng-1.2.41 */
1480 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
1481    /* Expand grayscale image to RGB
1482     */
1483    if (transforms & PNG_TRANSFORM_GRAY_TO_RGB)
1484        png_set_gray_to_rgb(png_ptr);
1485 #endif
1486 
1487    /* We don't handle adding filler bytes */
1488 
1489    /* Optional call to gamma correct and add the background to the palette
1490     * and update info structure.  REQUIRED if you are expecting libpng to
1491     * update the palette for you (i.e., you selected such a transform above).
1492     */
1493    png_read_update_info(png_ptr, info_ptr);
1494 
1495    /* -------------- image transformations end here ------------------- */
1496 
1497 #ifdef PNG_FREE_ME_SUPPORTED
1498    png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
1499 #endif
1500    if (info_ptr->row_pointers == NULL)
1501    {
1502       info_ptr->row_pointers = (png_bytepp)png_malloc(png_ptr,
1503          info_ptr->height * png_sizeof(png_bytep));
1504       png_memset(info_ptr->row_pointers, 0, info_ptr->height
1505          * png_sizeof(png_bytep));
1506 
1507 #ifdef PNG_FREE_ME_SUPPORTED
1508       info_ptr->free_me |= PNG_FREE_ROWS;
1509 #endif
1510 
1511       for (row = 0; row < (int)info_ptr->height; row++)
1512          info_ptr->row_pointers[row] = (png_bytep)png_malloc(png_ptr,
1513             png_get_rowbytes(png_ptr, info_ptr));
1514    }
1515 
1516    png_read_image(png_ptr, info_ptr->row_pointers);
1517    info_ptr->valid |= PNG_INFO_IDAT;
1518 
1519    /* Read rest of file, and get additional chunks in info_ptr - REQUIRED */
1520    png_read_end(png_ptr, info_ptr);
1521 
1522    transforms = transforms; /* Quiet compiler warnings */
1523    params = params;
1524 
1525 }
1526 #endif /* PNG_INFO_IMAGE_SUPPORTED */
1527 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
1528 #endif /* PNG_READ_SUPPORTED */
1529