2
/* pngrutil.c - utilities to read a PNG file
4
* Last changed in libpng 1.6.19 [November 12, 2015]
5
* Copyright (c) 1998-2015 Glenn Randers-Pehrson
6
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
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* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
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* This code is released under the libpng license.
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* For conditions of distribution and use, see the disclaimer
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* and license in png.h
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* This file contains routines that are only called from within
14
* libpng itself during the course of reading an image.
19
#ifdef PNG_READ_SUPPORTED
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png_get_uint_31(png_const_structrp png_ptr, png_const_bytep buf)
24
png_uint_32 uval = png_get_uint_32(buf);
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if (uval > PNG_UINT_31_MAX)
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png_error(png_ptr, "PNG unsigned integer out of range");
32
#if defined(PNG_READ_gAMA_SUPPORTED) || defined(PNG_READ_cHRM_SUPPORTED)
33
/* The following is a variation on the above for use with the fixed
34
* point values used for gAMA and cHRM. Instead of png_error it
35
* issues a warning and returns (-1) - an invalid value because both
36
* gAMA and cHRM use *unsigned* integers for fixed point values.
38
#define PNG_FIXED_ERROR (-1)
40
static png_fixed_point /* PRIVATE */
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png_get_fixed_point(png_structrp png_ptr, png_const_bytep buf)
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png_uint_32 uval = png_get_uint_32(buf);
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if (uval <= PNG_UINT_31_MAX)
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return (png_fixed_point)uval; /* known to be in range */
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/* The caller can turn off the warning by passing NULL. */
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png_warning(png_ptr, "PNG fixed point integer out of range");
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return PNG_FIXED_ERROR;
56
#ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
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/* NOTE: the read macros will obscure these definitions, so that if
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* PNG_USE_READ_MACROS is set the library will not use them internally,
59
* but the APIs will still be available externally.
61
* The parentheses around "PNGAPI function_name" in the following three
62
* functions are necessary because they allow the macros to co-exist with
63
* these (unused but exported) functions.
66
/* Grab an unsigned 32-bit integer from a buffer in big-endian format. */
68
png_get_uint_32)(png_const_bytep buf)
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((png_uint_32)(*(buf )) << 24) +
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((png_uint_32)(*(buf + 1)) << 16) +
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((png_uint_32)(*(buf + 2)) << 8) +
74
((png_uint_32)(*(buf + 3)) ) ;
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/* Grab a signed 32-bit integer from a buffer in big-endian format. The
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* data is stored in the PNG file in two's complement format and there
81
* is no guarantee that a 'png_int_32' is exactly 32 bits, therefore
82
* the following code does a two's complement to native conversion.
85
png_get_int_32)(png_const_bytep buf)
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png_uint_32 uval = png_get_uint_32(buf);
88
if ((uval & 0x80000000) == 0) /* non-negative */
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uval = (uval ^ 0xffffffff) + 1; /* 2's complement: -x = ~x+1 */
92
if ((uval & 0x80000000) == 0) /* no overflow */
93
return -(png_int_32)uval;
94
/* The following has to be safe; this function only gets called on PNG data
95
* and if we get here that data is invalid. 0 is the most safe value and
96
* if not then an attacker would surely just generate a PNG with 0 instead.
101
/* Grab an unsigned 16-bit integer from a buffer in big-endian format. */
103
png_get_uint_16)(png_const_bytep buf)
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/* ANSI-C requires an int value to accomodate at least 16 bits so this
106
* works and allows the compiler not to worry about possible narrowing
107
* on 32-bit systems. (Pre-ANSI systems did not make integers smaller
108
* than 16 bits either.)
111
((unsigned int)(*buf) << 8) +
112
((unsigned int)(*(buf + 1)));
114
return (png_uint_16)val;
117
#endif /* READ_INT_FUNCTIONS */
119
/* Read and check the PNG file signature */
121
png_read_sig(png_structrp png_ptr, png_inforp info_ptr)
123
png_size_t num_checked, num_to_check;
125
/* Exit if the user application does not expect a signature. */
126
if (png_ptr->sig_bytes >= 8)
129
num_checked = png_ptr->sig_bytes;
130
num_to_check = 8 - num_checked;
132
#ifdef PNG_IO_STATE_SUPPORTED
133
png_ptr->io_state = PNG_IO_READING | PNG_IO_SIGNATURE;
136
/* The signature must be serialized in a single I/O call. */
137
png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check);
138
png_ptr->sig_bytes = 8;
140
if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check) != 0)
142
if (num_checked < 4 &&
143
png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
144
png_error(png_ptr, "Not a PNG file");
146
png_error(png_ptr, "PNG file corrupted by ASCII conversion");
149
png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
152
/* Read the chunk header (length + type name).
153
* Put the type name into png_ptr->chunk_name, and return the length.
155
png_uint_32 /* PRIVATE */
156
png_read_chunk_header(png_structrp png_ptr)
161
#ifdef PNG_IO_STATE_SUPPORTED
162
png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_HDR;
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/* Read the length and the chunk name.
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* This must be performed in a single I/O call.
168
png_read_data(png_ptr, buf, 8);
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length = png_get_uint_31(png_ptr, buf);
171
/* Put the chunk name into png_ptr->chunk_name. */
172
png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(buf+4);
174
png_debug2(0, "Reading %lx chunk, length = %lu",
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(unsigned long)png_ptr->chunk_name, (unsigned long)length);
177
/* Reset the crc and run it over the chunk name. */
178
png_reset_crc(png_ptr);
179
png_calculate_crc(png_ptr, buf + 4, 4);
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/* Check to see if chunk name is valid. */
182
png_check_chunk_name(png_ptr, png_ptr->chunk_name);
184
#ifdef PNG_IO_STATE_SUPPORTED
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png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_DATA;
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/* Read data, and (optionally) run it through the CRC. */
193
png_crc_read(png_structrp png_ptr, png_bytep buf, png_uint_32 length)
198
png_read_data(png_ptr, buf, length);
199
png_calculate_crc(png_ptr, buf, length);
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/* Optionally skip data and then check the CRC. Depending on whether we
203
* are reading an ancillary or critical chunk, and how the program has set
204
* things up, we may calculate the CRC on the data and print a message.
205
* Returns '1' if there was a CRC error, '0' otherwise.
208
png_crc_finish(png_structrp png_ptr, png_uint_32 skip)
210
/* The size of the local buffer for inflate is a good guess as to a
211
* reasonable size to use for buffering reads from the application.
216
png_byte tmpbuf[PNG_INFLATE_BUF_SIZE];
218
len = (sizeof tmpbuf);
223
png_crc_read(png_ptr, tmpbuf, len);
226
if (png_crc_error(png_ptr) != 0)
228
if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0 ?
229
(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) == 0 :
230
(png_ptr->flags & PNG_FLAG_CRC_CRITICAL_USE) != 0)
232
png_chunk_warning(png_ptr, "CRC error");
236
png_chunk_error(png_ptr, "CRC error");
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/* Compare the CRC stored in the PNG file with that calculated by libpng from
245
* the data it has read thus far.
248
png_crc_error(png_structrp png_ptr)
250
png_byte crc_bytes[4];
254
if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0)
256
if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
257
(PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
263
if ((png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) != 0)
267
#ifdef PNG_IO_STATE_SUPPORTED
268
png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_CRC;
271
/* The chunk CRC must be serialized in a single I/O call. */
272
png_read_data(png_ptr, crc_bytes, 4);
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crc = png_get_uint_32(crc_bytes);
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return ((int)(crc != png_ptr->crc));
284
#if defined(PNG_READ_iCCP_SUPPORTED) || defined(PNG_READ_iTXt_SUPPORTED) ||\
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defined(PNG_READ_pCAL_SUPPORTED) || defined(PNG_READ_sCAL_SUPPORTED) ||\
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defined(PNG_READ_sPLT_SUPPORTED) || defined(PNG_READ_tEXt_SUPPORTED) ||\
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defined(PNG_READ_zTXt_SUPPORTED) || defined(PNG_SEQUENTIAL_READ_SUPPORTED)
288
/* Manage the read buffer; this simply reallocates the buffer if it is not small
289
* enough (or if it is not allocated). The routine returns a pointer to the
290
* buffer; if an error occurs and 'warn' is set the routine returns NULL, else
291
* it will call png_error (via png_malloc) on failure. (warn == 2 means
295
png_read_buffer(png_structrp png_ptr, png_alloc_size_t new_size, int warn)
297
png_bytep buffer = png_ptr->read_buffer;
299
if (buffer != NULL && new_size > png_ptr->read_buffer_size)
301
png_ptr->read_buffer = NULL;
302
png_ptr->read_buffer = NULL;
303
png_ptr->read_buffer_size = 0;
304
png_free(png_ptr, buffer);
310
buffer = png_voidcast(png_bytep, png_malloc_base(png_ptr, new_size));
314
png_ptr->read_buffer = buffer;
315
png_ptr->read_buffer_size = new_size;
318
else if (warn < 2) /* else silent */
321
png_chunk_warning(png_ptr, "insufficient memory to read chunk");
324
png_chunk_error(png_ptr, "insufficient memory to read chunk");
330
#endif /* READ_iCCP|iTXt|pCAL|sCAL|sPLT|tEXt|zTXt|SEQUENTIAL_READ */
332
/* png_inflate_claim: claim the zstream for some nefarious purpose that involves
333
* decompression. Returns Z_OK on success, else a zlib error code. It checks
334
* the owner but, in final release builds, just issues a warning if some other
335
* chunk apparently owns the stream. Prior to release it does a png_error.
338
png_inflate_claim(png_structrp png_ptr, png_uint_32 owner)
340
if (png_ptr->zowner != 0)
344
PNG_STRING_FROM_CHUNK(msg, png_ptr->zowner);
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/* So the message that results is "<chunk> using zstream"; this is an
346
* internal error, but is very useful for debugging. i18n requirements
349
(void)png_safecat(msg, (sizeof msg), 4, " using zstream");
350
#if PNG_RELEASE_BUILD
351
png_chunk_warning(png_ptr, msg);
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png_chunk_error(png_ptr, msg);
358
/* Implementation note: unlike 'png_deflate_claim' this internal function
359
* does not take the size of the data as an argument. Some efficiency could
360
* be gained by using this when it is known *if* the zlib stream itself does
361
* not record the number; however, this is an illusion: the original writer
362
* of the PNG may have selected a lower window size, and we really must
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* follow that because, for systems with with limited capabilities, we
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* would otherwise reject the application's attempts to use a smaller window
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* size (zlib doesn't have an interface to say "this or lower"!).
367
* inflateReset2 was added to zlib 1.2.4; before this the window could not be
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* reset, therefore it is necessary to always allocate the maximum window
369
* size with earlier zlibs just in case later compressed chunks need it.
372
int ret; /* zlib return code */
373
#if PNG_ZLIB_VERNUM >= 0x1240
375
# if defined(PNG_SET_OPTION_SUPPORTED) && defined(PNG_MAXIMUM_INFLATE_WINDOW)
378
if (((png_ptr->options >> PNG_MAXIMUM_INFLATE_WINDOW) & 3) ==
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# define window_bits 0
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/* Set this for safety, just in case the previous owner left pointers to
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* memory allocations.
392
png_ptr->zstream.next_in = NULL;
393
png_ptr->zstream.avail_in = 0;
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png_ptr->zstream.next_out = NULL;
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png_ptr->zstream.avail_out = 0;
397
if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
399
#if PNG_ZLIB_VERNUM < 0x1240
400
ret = inflateReset(&png_ptr->zstream);
402
ret = inflateReset2(&png_ptr->zstream, window_bits);
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#if PNG_ZLIB_VERNUM < 0x1240
409
ret = inflateInit(&png_ptr->zstream);
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ret = inflateInit2(&png_ptr->zstream, window_bits);
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png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED;
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png_ptr->zowner = owner;
422
png_zstream_error(png_ptr, ret);
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#ifdef PNG_READ_COMPRESSED_TEXT_SUPPORTED
433
/* png_inflate now returns zlib error codes including Z_OK and Z_STREAM_END to
434
* allow the caller to do multiple calls if required. If the 'finish' flag is
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* set Z_FINISH will be passed to the final inflate() call and Z_STREAM_END must
436
* be returned or there has been a problem, otherwise Z_SYNC_FLUSH is used and
437
* Z_OK or Z_STREAM_END will be returned on success.
439
* The input and output sizes are updated to the actual amounts of data consumed
440
* or written, not the amount available (as in a z_stream). The data pointers
441
* are not changed, so the next input is (data+input_size) and the next
442
* available output is (output+output_size).
445
png_inflate(png_structrp png_ptr, png_uint_32 owner, int finish,
446
/* INPUT: */ png_const_bytep input, png_uint_32p input_size_ptr,
447
/* OUTPUT: */ png_bytep output, png_alloc_size_t *output_size_ptr)
449
if (png_ptr->zowner == owner) /* Else not claimed */
452
png_alloc_size_t avail_out = *output_size_ptr;
453
png_uint_32 avail_in = *input_size_ptr;
455
/* zlib can't necessarily handle more than 65535 bytes at once (i.e. it
456
* can't even necessarily handle 65536 bytes) because the type uInt is
457
* "16 bits or more". Consequently it is necessary to chunk the input to
458
* zlib. This code uses ZLIB_IO_MAX, from pngpriv.h, as the maximum (the
459
* maximum value that can be stored in a uInt.) It is possible to set
460
* ZLIB_IO_MAX to a lower value in pngpriv.h and this may sometimes have
461
* a performance advantage, because it reduces the amount of data accessed
462
* at each step and that may give the OS more time to page it in.
464
png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input);
465
/* avail_in and avail_out are set below from 'size' */
466
png_ptr->zstream.avail_in = 0;
467
png_ptr->zstream.avail_out = 0;
469
/* Read directly into the output if it is available (this is set to
470
* a local buffer below if output is NULL).
473
png_ptr->zstream.next_out = output;
478
Byte local_buffer[PNG_INFLATE_BUF_SIZE];
480
/* zlib INPUT BUFFER */
481
/* The setting of 'avail_in' used to be outside the loop; by setting it
482
* inside it is possible to chunk the input to zlib and simply rely on
483
* zlib to advance the 'next_in' pointer. This allows arbitrary
484
* amounts of data to be passed through zlib at the unavoidable cost of
485
* requiring a window save (memcpy of up to 32768 output bytes)
486
* every ZLIB_IO_MAX input bytes.
488
avail_in += png_ptr->zstream.avail_in; /* not consumed last time */
492
if (avail_in < avail)
493
avail = (uInt)avail_in; /* safe: < than ZLIB_IO_MAX */
496
png_ptr->zstream.avail_in = avail;
498
/* zlib OUTPUT BUFFER */
499
avail_out += png_ptr->zstream.avail_out; /* not written last time */
501
avail = ZLIB_IO_MAX; /* maximum zlib can process */
505
/* Reset the output buffer each time round if output is NULL and
506
* make available the full buffer, up to 'remaining_space'
508
png_ptr->zstream.next_out = local_buffer;
509
if ((sizeof local_buffer) < avail)
510
avail = (sizeof local_buffer);
513
if (avail_out < avail)
514
avail = (uInt)avail_out; /* safe: < ZLIB_IO_MAX */
516
png_ptr->zstream.avail_out = avail;
519
/* zlib inflate call */
520
/* In fact 'avail_out' may be 0 at this point, that happens at the end
521
* of the read when the final LZ end code was not passed at the end of
522
* the previous chunk of input data. Tell zlib if we have reached the
523
* end of the output buffer.
525
ret = inflate(&png_ptr->zstream, avail_out > 0 ? Z_NO_FLUSH :
526
(finish ? Z_FINISH : Z_SYNC_FLUSH));
527
} while (ret == Z_OK);
529
/* For safety kill the local buffer pointer now */
531
png_ptr->zstream.next_out = NULL;
533
/* Claw back the 'size' and 'remaining_space' byte counts. */
534
avail_in += png_ptr->zstream.avail_in;
535
avail_out += png_ptr->zstream.avail_out;
537
/* Update the input and output sizes; the updated values are the amount
538
* consumed or written, effectively the inverse of what zlib uses.
541
*output_size_ptr -= avail_out;
544
*input_size_ptr -= avail_in;
546
/* Ensure png_ptr->zstream.msg is set (even in the success case!) */
547
png_zstream_error(png_ptr, ret);
553
/* This is a bad internal error. The recovery assigns to the zstream msg
554
* pointer, which is not owned by the caller, but this is safe; it's only
557
png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed");
558
return Z_STREAM_ERROR;
563
* Decompress trailing data in a chunk. The assumption is that read_buffer
564
* points at an allocated area holding the contents of a chunk with a
565
* trailing compressed part. What we get back is an allocated area
566
* holding the original prefix part and an uncompressed version of the
567
* trailing part (the malloc area passed in is freed).
570
png_decompress_chunk(png_structrp png_ptr,
571
png_uint_32 chunklength, png_uint_32 prefix_size,
572
png_alloc_size_t *newlength /* must be initialized to the maximum! */,
573
int terminate /*add a '\0' to the end of the uncompressed data*/)
575
/* TODO: implement different limits for different types of chunk.
577
* The caller supplies *newlength set to the maximum length of the
578
* uncompressed data, but this routine allocates space for the prefix and
579
* maybe a '\0' terminator too. We have to assume that 'prefix_size' is
580
* limited only by the maximum chunk size.
582
png_alloc_size_t limit = PNG_SIZE_MAX;
584
# ifdef PNG_SET_USER_LIMITS_SUPPORTED
585
if (png_ptr->user_chunk_malloc_max > 0 &&
586
png_ptr->user_chunk_malloc_max < limit)
587
limit = png_ptr->user_chunk_malloc_max;
588
# elif PNG_USER_CHUNK_MALLOC_MAX > 0
589
if (PNG_USER_CHUNK_MALLOC_MAX < limit)
590
limit = PNG_USER_CHUNK_MALLOC_MAX;
593
if (limit >= prefix_size + (terminate != 0))
597
limit -= prefix_size + (terminate != 0);
599
if (limit < *newlength)
602
/* Now try to claim the stream. */
603
ret = png_inflate_claim(png_ptr, png_ptr->chunk_name);
607
png_uint_32 lzsize = chunklength - prefix_size;
609
ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/,
610
/* input: */ png_ptr->read_buffer + prefix_size, &lzsize,
611
/* output: */ NULL, newlength);
613
if (ret == Z_STREAM_END)
615
/* Use 'inflateReset' here, not 'inflateReset2' because this
616
* preserves the previously decided window size (otherwise it would
617
* be necessary to store the previous window size.) In practice
618
* this doesn't matter anyway, because png_inflate will call inflate
619
* with Z_FINISH in almost all cases, so the window will not be
622
if (inflateReset(&png_ptr->zstream) == Z_OK)
624
/* Because of the limit checks above we know that the new,
625
* expanded, size will fit in a size_t (let alone an
626
* png_alloc_size_t). Use png_malloc_base here to avoid an
629
png_alloc_size_t new_size = *newlength;
630
png_alloc_size_t buffer_size = prefix_size + new_size +
632
png_bytep text = png_voidcast(png_bytep, png_malloc_base(png_ptr,
637
ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/,
638
png_ptr->read_buffer + prefix_size, &lzsize,
639
text + prefix_size, newlength);
641
if (ret == Z_STREAM_END)
643
if (new_size == *newlength)
646
text[prefix_size + *newlength] = 0;
649
memcpy(text, png_ptr->read_buffer, prefix_size);
652
png_bytep old_ptr = png_ptr->read_buffer;
654
png_ptr->read_buffer = text;
655
png_ptr->read_buffer_size = buffer_size;
656
text = old_ptr; /* freed below */
662
/* The size changed on the second read, there can be no
663
* guarantee that anything is correct at this point.
664
* The 'msg' pointer has been set to "unexpected end of
665
* LZ stream", which is fine, but return an error code
666
* that the caller won't accept.
668
ret = PNG_UNEXPECTED_ZLIB_RETURN;
672
else if (ret == Z_OK)
673
ret = PNG_UNEXPECTED_ZLIB_RETURN; /* for safety */
675
/* Free the text pointer (this is the old read_buffer on
678
png_free(png_ptr, text);
680
/* This really is very benign, but it's still an error because
681
* the extra space may otherwise be used as a Trojan Horse.
683
if (ret == Z_STREAM_END &&
684
chunklength - prefix_size != lzsize)
685
png_chunk_benign_error(png_ptr, "extra compressed data");
690
/* Out of memory allocating the buffer */
692
png_zstream_error(png_ptr, Z_MEM_ERROR);
698
/* inflateReset failed, store the error message */
699
png_zstream_error(png_ptr, ret);
701
if (ret == Z_STREAM_END)
702
ret = PNG_UNEXPECTED_ZLIB_RETURN;
706
else if (ret == Z_OK)
707
ret = PNG_UNEXPECTED_ZLIB_RETURN;
709
/* Release the claimed stream */
713
else /* the claim failed */ if (ret == Z_STREAM_END) /* impossible! */
714
ret = PNG_UNEXPECTED_ZLIB_RETURN;
721
/* Application/configuration limits exceeded */
722
png_zstream_error(png_ptr, Z_MEM_ERROR);
726
#endif /* READ_COMPRESSED_TEXT */
728
#ifdef PNG_READ_iCCP_SUPPORTED
729
/* Perform a partial read and decompress, producing 'avail_out' bytes and
730
* reading from the current chunk as required.
733
png_inflate_read(png_structrp png_ptr, png_bytep read_buffer, uInt read_size,
734
png_uint_32p chunk_bytes, png_bytep next_out, png_alloc_size_t *out_size,
737
if (png_ptr->zowner == png_ptr->chunk_name)
741
/* next_in and avail_in must have been initialized by the caller. */
742
png_ptr->zstream.next_out = next_out;
743
png_ptr->zstream.avail_out = 0; /* set in the loop */
747
if (png_ptr->zstream.avail_in == 0)
749
if (read_size > *chunk_bytes)
750
read_size = (uInt)*chunk_bytes;
751
*chunk_bytes -= read_size;
754
png_crc_read(png_ptr, read_buffer, read_size);
756
png_ptr->zstream.next_in = read_buffer;
757
png_ptr->zstream.avail_in = read_size;
760
if (png_ptr->zstream.avail_out == 0)
762
uInt avail = ZLIB_IO_MAX;
763
if (avail > *out_size)
764
avail = (uInt)*out_size;
767
png_ptr->zstream.avail_out = avail;
770
/* Use Z_SYNC_FLUSH when there is no more chunk data to ensure that all
771
* the available output is produced; this allows reading of truncated
774
ret = inflate(&png_ptr->zstream,
775
*chunk_bytes > 0 ? Z_NO_FLUSH : (finish ? Z_FINISH : Z_SYNC_FLUSH));
777
while (ret == Z_OK && (*out_size > 0 || png_ptr->zstream.avail_out > 0));
779
*out_size += png_ptr->zstream.avail_out;
780
png_ptr->zstream.avail_out = 0; /* Should not be required, but is safe */
782
/* Ensure the error message pointer is always set: */
783
png_zstream_error(png_ptr, ret);
789
png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed");
790
return Z_STREAM_ERROR;
795
/* Read and check the IDHR chunk */
798
png_handle_IHDR(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
801
png_uint_32 width, height;
802
int bit_depth, color_type, compression_type, filter_type;
805
png_debug(1, "in png_handle_IHDR");
807
if ((png_ptr->mode & PNG_HAVE_IHDR) != 0)
808
png_chunk_error(png_ptr, "out of place");
810
/* Check the length */
812
png_chunk_error(png_ptr, "invalid");
814
png_ptr->mode |= PNG_HAVE_IHDR;
816
png_crc_read(png_ptr, buf, 13);
817
png_crc_finish(png_ptr, 0);
819
width = png_get_uint_31(png_ptr, buf);
820
height = png_get_uint_31(png_ptr, buf + 4);
823
compression_type = buf[10];
824
filter_type = buf[11];
825
interlace_type = buf[12];
827
/* Set internal variables */
828
png_ptr->width = width;
829
png_ptr->height = height;
830
png_ptr->bit_depth = (png_byte)bit_depth;
831
png_ptr->interlaced = (png_byte)interlace_type;
832
png_ptr->color_type = (png_byte)color_type;
833
#ifdef PNG_MNG_FEATURES_SUPPORTED
834
png_ptr->filter_type = (png_byte)filter_type;
836
png_ptr->compression_type = (png_byte)compression_type;
838
/* Find number of channels */
839
switch (png_ptr->color_type)
841
default: /* invalid, png_set_IHDR calls png_error */
842
case PNG_COLOR_TYPE_GRAY:
843
case PNG_COLOR_TYPE_PALETTE:
844
png_ptr->channels = 1;
847
case PNG_COLOR_TYPE_RGB:
848
png_ptr->channels = 3;
851
case PNG_COLOR_TYPE_GRAY_ALPHA:
852
png_ptr->channels = 2;
855
case PNG_COLOR_TYPE_RGB_ALPHA:
856
png_ptr->channels = 4;
860
/* Set up other useful info */
861
png_ptr->pixel_depth = (png_byte)(png_ptr->bit_depth * png_ptr->channels);
862
png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->width);
863
png_debug1(3, "bit_depth = %d", png_ptr->bit_depth);
864
png_debug1(3, "channels = %d", png_ptr->channels);
865
png_debug1(3, "rowbytes = %lu", (unsigned long)png_ptr->rowbytes);
866
png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth,
867
color_type, interlace_type, compression_type, filter_type);
870
/* Read and check the palette */
872
png_handle_PLTE(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
874
png_color palette[PNG_MAX_PALETTE_LENGTH];
875
int max_palette_length, num, i;
876
#ifdef PNG_POINTER_INDEXING_SUPPORTED
880
png_debug(1, "in png_handle_PLTE");
882
if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
883
png_chunk_error(png_ptr, "missing IHDR");
885
/* Moved to before the 'after IDAT' check below because otherwise duplicate
886
* PLTE chunks are potentially ignored (the spec says there shall not be more
887
* than one PLTE, the error is not treated as benign, so this check trumps
888
* the requirement that PLTE appears before IDAT.)
890
else if ((png_ptr->mode & PNG_HAVE_PLTE) != 0)
891
png_chunk_error(png_ptr, "duplicate");
893
else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
895
/* This is benign because the non-benign error happened before, when an
896
* IDAT was encountered in a color-mapped image with no PLTE.
898
png_crc_finish(png_ptr, length);
899
png_chunk_benign_error(png_ptr, "out of place");
903
png_ptr->mode |= PNG_HAVE_PLTE;
905
if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
907
png_crc_finish(png_ptr, length);
908
png_chunk_benign_error(png_ptr, "ignored in grayscale PNG");
912
#ifndef PNG_READ_OPT_PLTE_SUPPORTED
913
if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
915
png_crc_finish(png_ptr, length);
920
if (length > 3*PNG_MAX_PALETTE_LENGTH || length % 3)
922
png_crc_finish(png_ptr, length);
924
if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
925
png_chunk_benign_error(png_ptr, "invalid");
928
png_chunk_error(png_ptr, "invalid");
933
/* The cast is safe because 'length' is less than 3*PNG_MAX_PALETTE_LENGTH */
934
num = (int)length / 3;
936
/* If the palette has 256 or fewer entries but is too large for the bit
937
* depth, we don't issue an error, to preserve the behavior of previous
938
* libpng versions. We silently truncate the unused extra palette entries
941
if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
942
max_palette_length = (1 << png_ptr->bit_depth);
944
max_palette_length = PNG_MAX_PALETTE_LENGTH;
946
if (num > max_palette_length)
947
num = max_palette_length;
949
#ifdef PNG_POINTER_INDEXING_SUPPORTED
950
for (i = 0, pal_ptr = palette; i < num; i++, pal_ptr++)
954
png_crc_read(png_ptr, buf, 3);
955
pal_ptr->red = buf[0];
956
pal_ptr->green = buf[1];
957
pal_ptr->blue = buf[2];
960
for (i = 0; i < num; i++)
964
png_crc_read(png_ptr, buf, 3);
965
/* Don't depend upon png_color being any order */
966
palette[i].red = buf[0];
967
palette[i].green = buf[1];
968
palette[i].blue = buf[2];
972
/* If we actually need the PLTE chunk (ie for a paletted image), we do
973
* whatever the normal CRC configuration tells us. However, if we
974
* have an RGB image, the PLTE can be considered ancillary, so
975
* we will act as though it is.
977
#ifndef PNG_READ_OPT_PLTE_SUPPORTED
978
if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
981
png_crc_finish(png_ptr, (int) length - num * 3);
984
#ifndef PNG_READ_OPT_PLTE_SUPPORTED
985
else if (png_crc_error(png_ptr) != 0) /* Only if we have a CRC error */
987
/* If we don't want to use the data from an ancillary chunk,
988
* we have two options: an error abort, or a warning and we
989
* ignore the data in this chunk (which should be OK, since
990
* it's considered ancillary for a RGB or RGBA image).
992
* IMPLEMENTATION NOTE: this is only here because png_crc_finish uses the
993
* chunk type to determine whether to check the ancillary or the critical
996
if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_USE) == 0)
998
if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) != 0)
1002
png_chunk_error(png_ptr, "CRC error");
1005
/* Otherwise, we (optionally) emit a warning and use the chunk. */
1006
else if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) == 0)
1007
png_chunk_warning(png_ptr, "CRC error");
1011
/* TODO: png_set_PLTE has the side effect of setting png_ptr->palette to its
1012
* own copy of the palette. This has the side effect that when png_start_row
1013
* is called (this happens after any call to png_read_update_info) the
1014
* info_ptr palette gets changed. This is extremely unexpected and
1017
* Fix this by not sharing the palette in this way.
1019
png_set_PLTE(png_ptr, info_ptr, palette, num);
1021
/* The three chunks, bKGD, hIST and tRNS *must* appear after PLTE and before
1022
* IDAT. Prior to 1.6.0 this was not checked; instead the code merely
1023
* checked the apparent validity of a tRNS chunk inserted before PLTE on a
1024
* palette PNG. 1.6.0 attempts to rigorously follow the standard and
1025
* therefore does a benign error if the erroneous condition is detected *and*
1026
* cancels the tRNS if the benign error returns. The alternative is to
1027
* amend the standard since it would be rather hypocritical of the standards
1028
* maintainers to ignore it.
1030
#ifdef PNG_READ_tRNS_SUPPORTED
1031
if (png_ptr->num_trans > 0 ||
1032
(info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0))
1034
/* Cancel this because otherwise it would be used if the transforms
1035
* require it. Don't cancel the 'valid' flag because this would prevent
1036
* detection of duplicate chunks.
1038
png_ptr->num_trans = 0;
1040
if (info_ptr != NULL)
1041
info_ptr->num_trans = 0;
1043
png_chunk_benign_error(png_ptr, "tRNS must be after");
1047
#ifdef PNG_READ_hIST_SUPPORTED
1048
if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0)
1049
png_chunk_benign_error(png_ptr, "hIST must be after");
1052
#ifdef PNG_READ_bKGD_SUPPORTED
1053
if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0)
1054
png_chunk_benign_error(png_ptr, "bKGD must be after");
1059
png_handle_IEND(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1061
png_debug(1, "in png_handle_IEND");
1063
if ((png_ptr->mode & PNG_HAVE_IHDR) == 0 ||
1064
(png_ptr->mode & PNG_HAVE_IDAT) == 0)
1065
png_chunk_error(png_ptr, "out of place");
1067
png_ptr->mode |= (PNG_AFTER_IDAT | PNG_HAVE_IEND);
1069
png_crc_finish(png_ptr, length);
1072
png_chunk_benign_error(png_ptr, "invalid");
1074
PNG_UNUSED(info_ptr)
1077
#ifdef PNG_READ_gAMA_SUPPORTED
1079
png_handle_gAMA(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1081
png_fixed_point igamma;
1084
png_debug(1, "in png_handle_gAMA");
1086
if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1087
png_chunk_error(png_ptr, "missing IHDR");
1089
else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
1091
png_crc_finish(png_ptr, length);
1092
png_chunk_benign_error(png_ptr, "out of place");
1098
png_crc_finish(png_ptr, length);
1099
png_chunk_benign_error(png_ptr, "invalid");
1103
png_crc_read(png_ptr, buf, 4);
1105
if (png_crc_finish(png_ptr, 0) != 0)
1108
igamma = png_get_fixed_point(NULL, buf);
1110
png_colorspace_set_gamma(png_ptr, &png_ptr->colorspace, igamma);
1111
png_colorspace_sync(png_ptr, info_ptr);
1115
#ifdef PNG_READ_sBIT_SUPPORTED
1117
png_handle_sBIT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1119
unsigned int truelen, i;
1120
png_byte sample_depth;
1123
png_debug(1, "in png_handle_sBIT");
1125
if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1126
png_chunk_error(png_ptr, "missing IHDR");
1128
else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
1130
png_crc_finish(png_ptr, length);
1131
png_chunk_benign_error(png_ptr, "out of place");
1135
if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT) != 0)
1137
png_crc_finish(png_ptr, length);
1138
png_chunk_benign_error(png_ptr, "duplicate");
1142
if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1150
truelen = png_ptr->channels;
1151
sample_depth = png_ptr->bit_depth;
1154
if (length != truelen || length > 4)
1156
png_chunk_benign_error(png_ptr, "invalid");
1157
png_crc_finish(png_ptr, length);
1161
buf[0] = buf[1] = buf[2] = buf[3] = sample_depth;
1162
png_crc_read(png_ptr, buf, truelen);
1164
if (png_crc_finish(png_ptr, 0) != 0)
1167
for (i=0; i<truelen; ++i)
1169
if (buf[i] == 0 || buf[i] > sample_depth)
1171
png_chunk_benign_error(png_ptr, "invalid");
1176
if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
1178
png_ptr->sig_bit.red = buf[0];
1179
png_ptr->sig_bit.green = buf[1];
1180
png_ptr->sig_bit.blue = buf[2];
1181
png_ptr->sig_bit.alpha = buf[3];
1186
png_ptr->sig_bit.gray = buf[0];
1187
png_ptr->sig_bit.red = buf[0];
1188
png_ptr->sig_bit.green = buf[0];
1189
png_ptr->sig_bit.blue = buf[0];
1190
png_ptr->sig_bit.alpha = buf[1];
1193
png_set_sBIT(png_ptr, info_ptr, &(png_ptr->sig_bit));
1197
#ifdef PNG_READ_cHRM_SUPPORTED
1199
png_handle_cHRM(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1204
png_debug(1, "in png_handle_cHRM");
1206
if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1207
png_chunk_error(png_ptr, "missing IHDR");
1209
else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
1211
png_crc_finish(png_ptr, length);
1212
png_chunk_benign_error(png_ptr, "out of place");
1218
png_crc_finish(png_ptr, length);
1219
png_chunk_benign_error(png_ptr, "invalid");
1223
png_crc_read(png_ptr, buf, 32);
1225
if (png_crc_finish(png_ptr, 0) != 0)
1228
xy.whitex = png_get_fixed_point(NULL, buf);
1229
xy.whitey = png_get_fixed_point(NULL, buf + 4);
1230
xy.redx = png_get_fixed_point(NULL, buf + 8);
1231
xy.redy = png_get_fixed_point(NULL, buf + 12);
1232
xy.greenx = png_get_fixed_point(NULL, buf + 16);
1233
xy.greeny = png_get_fixed_point(NULL, buf + 20);
1234
xy.bluex = png_get_fixed_point(NULL, buf + 24);
1235
xy.bluey = png_get_fixed_point(NULL, buf + 28);
1237
if (xy.whitex == PNG_FIXED_ERROR ||
1238
xy.whitey == PNG_FIXED_ERROR ||
1239
xy.redx == PNG_FIXED_ERROR ||
1240
xy.redy == PNG_FIXED_ERROR ||
1241
xy.greenx == PNG_FIXED_ERROR ||
1242
xy.greeny == PNG_FIXED_ERROR ||
1243
xy.bluex == PNG_FIXED_ERROR ||
1244
xy.bluey == PNG_FIXED_ERROR)
1246
png_chunk_benign_error(png_ptr, "invalid values");
1250
/* If a colorspace error has already been output skip this chunk */
1251
if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
1254
if ((png_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) != 0)
1256
png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
1257
png_colorspace_sync(png_ptr, info_ptr);
1258
png_chunk_benign_error(png_ptr, "duplicate");
1262
png_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;
1263
(void)png_colorspace_set_chromaticities(png_ptr, &png_ptr->colorspace, &xy,
1264
1/*prefer cHRM values*/);
1265
png_colorspace_sync(png_ptr, info_ptr);
1269
#ifdef PNG_READ_sRGB_SUPPORTED
1271
png_handle_sRGB(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1275
png_debug(1, "in png_handle_sRGB");
1277
if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1278
png_chunk_error(png_ptr, "missing IHDR");
1280
else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
1282
png_crc_finish(png_ptr, length);
1283
png_chunk_benign_error(png_ptr, "out of place");
1289
png_crc_finish(png_ptr, length);
1290
png_chunk_benign_error(png_ptr, "invalid");
1294
png_crc_read(png_ptr, &intent, 1);
1296
if (png_crc_finish(png_ptr, 0) != 0)
1299
/* If a colorspace error has already been output skip this chunk */
1300
if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
1303
/* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
1306
if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) != 0)
1308
png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
1309
png_colorspace_sync(png_ptr, info_ptr);
1310
png_chunk_benign_error(png_ptr, "too many profiles");
1314
(void)png_colorspace_set_sRGB(png_ptr, &png_ptr->colorspace, intent);
1315
png_colorspace_sync(png_ptr, info_ptr);
1317
#endif /* READ_sRGB */
1319
#ifdef PNG_READ_iCCP_SUPPORTED
1321
png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1322
/* Note: this does not properly handle profiles that are > 64K under DOS */
1324
png_const_charp errmsg = NULL; /* error message output, or no error */
1325
int finished = 0; /* crc checked */
1327
png_debug(1, "in png_handle_iCCP");
1329
if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1330
png_chunk_error(png_ptr, "missing IHDR");
1332
else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
1334
png_crc_finish(png_ptr, length);
1335
png_chunk_benign_error(png_ptr, "out of place");
1339
/* Consistent with all the above colorspace handling an obviously *invalid*
1340
* chunk is just ignored, so does not invalidate the color space. An
1341
* alternative is to set the 'invalid' flags at the start of this routine
1342
* and only clear them in they were not set before and all the tests pass.
1343
* The minimum 'deflate' stream is assumed to be just the 2 byte header and
1344
* 4 byte checksum. The keyword must be at least one character and there is
1345
* a terminator (0) byte and the compression method.
1349
png_crc_finish(png_ptr, length);
1350
png_chunk_benign_error(png_ptr, "too short");
1354
/* If a colorspace error has already been output skip this chunk */
1355
if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
1357
png_crc_finish(png_ptr, length);
1361
/* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
1364
if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) == 0)
1366
uInt read_length, keyword_length;
1369
/* Find the keyword; the keyword plus separator and compression method
1370
* bytes can be at most 81 characters long.
1372
read_length = 81; /* maximum */
1373
if (read_length > length)
1374
read_length = (uInt)length;
1376
png_crc_read(png_ptr, (png_bytep)keyword, read_length);
1377
length -= read_length;
1380
while (keyword_length < 80 && keyword_length < read_length &&
1381
keyword[keyword_length] != 0)
1384
/* TODO: make the keyword checking common */
1385
if (keyword_length >= 1 && keyword_length <= 79)
1387
/* We only understand '0' compression - deflate - so if we get a
1388
* different value we can't safely decode the chunk.
1390
if (keyword_length+1 < read_length &&
1391
keyword[keyword_length+1] == PNG_COMPRESSION_TYPE_BASE)
1393
read_length -= keyword_length+2;
1395
if (png_inflate_claim(png_ptr, png_iCCP) == Z_OK)
1397
Byte profile_header[132];
1398
Byte local_buffer[PNG_INFLATE_BUF_SIZE];
1399
png_alloc_size_t size = (sizeof profile_header);
1401
png_ptr->zstream.next_in = (Bytef*)keyword + (keyword_length+2);
1402
png_ptr->zstream.avail_in = read_length;
1403
(void)png_inflate_read(png_ptr, local_buffer,
1404
(sizeof local_buffer), &length, profile_header, &size,
1405
0/*finish: don't, because the output is too small*/);
1409
/* We have the ICC profile header; do the basic header checks.
1411
const png_uint_32 profile_length =
1412
png_get_uint_32(profile_header);
1414
if (png_icc_check_length(png_ptr, &png_ptr->colorspace,
1415
keyword, profile_length) != 0)
1417
/* The length is apparently ok, so we can check the 132
1420
if (png_icc_check_header(png_ptr, &png_ptr->colorspace,
1421
keyword, profile_length, profile_header,
1422
png_ptr->color_type) != 0)
1424
/* Now read the tag table; a variable size buffer is
1425
* needed at this point, allocate one for the whole
1426
* profile. The header check has already validated
1427
* that none of these stuff will overflow.
1429
const png_uint_32 tag_count = png_get_uint_32(
1430
profile_header+128);
1431
png_bytep profile = png_read_buffer(png_ptr,
1432
profile_length, 2/*silent*/);
1434
if (profile != NULL)
1436
memcpy(profile, profile_header,
1437
(sizeof profile_header));
1439
size = 12 * tag_count;
1441
(void)png_inflate_read(png_ptr, local_buffer,
1442
(sizeof local_buffer), &length,
1443
profile + (sizeof profile_header), &size, 0);
1445
/* Still expect a buffer error because we expect
1446
* there to be some tag data!
1450
if (png_icc_check_tag_table(png_ptr,
1451
&png_ptr->colorspace, keyword, profile_length,
1454
/* The profile has been validated for basic
1455
* security issues, so read the whole thing in.
1457
size = profile_length - (sizeof profile_header)
1460
(void)png_inflate_read(png_ptr, local_buffer,
1461
(sizeof local_buffer), &length,
1462
profile + (sizeof profile_header) +
1463
12 * tag_count, &size, 1/*finish*/);
1465
if (length > 0 && !(png_ptr->flags &
1466
PNG_FLAG_BENIGN_ERRORS_WARN))
1467
errmsg = "extra compressed data";
1469
/* But otherwise allow extra data: */
1474
/* This can be handled completely, so
1477
png_chunk_warning(png_ptr,
1478
"extra compressed data");
1481
png_crc_finish(png_ptr, length);
1484
# ifdef PNG_sRGB_SUPPORTED
1485
/* Check for a match against sRGB */
1486
png_icc_set_sRGB(png_ptr,
1487
&png_ptr->colorspace, profile,
1488
png_ptr->zstream.adler);
1491
/* Steal the profile for info_ptr. */
1492
if (info_ptr != NULL)
1494
png_free_data(png_ptr, info_ptr,
1497
info_ptr->iccp_name = png_voidcast(char*,
1498
png_malloc_base(png_ptr,
1500
if (info_ptr->iccp_name != NULL)
1502
memcpy(info_ptr->iccp_name, keyword,
1504
info_ptr->iccp_proflen =
1506
info_ptr->iccp_profile = profile;
1507
png_ptr->read_buffer = NULL; /*steal*/
1508
info_ptr->free_me |= PNG_FREE_ICCP;
1509
info_ptr->valid |= PNG_INFO_iCCP;
1514
png_ptr->colorspace.flags |=
1515
PNG_COLORSPACE_INVALID;
1516
errmsg = "out of memory";
1520
/* else the profile remains in the read
1521
* buffer which gets reused for subsequent
1525
if (info_ptr != NULL)
1526
png_colorspace_sync(png_ptr, info_ptr);
1530
png_ptr->zowner = 0;
1536
errmsg = "truncated";
1538
#ifndef __COVERITY__
1540
errmsg = png_ptr->zstream.msg;
1544
/* else png_icc_check_tag_table output an error */
1547
else /* profile truncated */
1548
errmsg = png_ptr->zstream.msg;
1552
errmsg = "out of memory";
1555
/* else png_icc_check_header output an error */
1558
/* else png_icc_check_length output an error */
1561
else /* profile truncated */
1562
errmsg = png_ptr->zstream.msg;
1564
/* Release the stream */
1565
png_ptr->zowner = 0;
1568
else /* png_inflate_claim failed */
1569
errmsg = png_ptr->zstream.msg;
1573
errmsg = "bad compression method"; /* or missing */
1577
errmsg = "bad keyword";
1581
errmsg = "too many profiles";
1583
/* Failure: the reason is in 'errmsg' */
1585
png_crc_finish(png_ptr, length);
1587
png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
1588
png_colorspace_sync(png_ptr, info_ptr);
1589
if (errmsg != NULL) /* else already output */
1590
png_chunk_benign_error(png_ptr, errmsg);
1592
#endif /* READ_iCCP */
1594
#ifdef PNG_READ_sPLT_SUPPORTED
1596
png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1597
/* Note: this does not properly handle chunks that are > 64K under DOS */
1599
png_bytep entry_start, buffer;
1600
png_sPLT_t new_palette;
1602
png_uint_32 data_length;
1604
png_uint_32 skip = 0;
1608
png_debug(1, "in png_handle_sPLT");
1610
#ifdef PNG_USER_LIMITS_SUPPORTED
1611
if (png_ptr->user_chunk_cache_max != 0)
1613
if (png_ptr->user_chunk_cache_max == 1)
1615
png_crc_finish(png_ptr, length);
1619
if (--png_ptr->user_chunk_cache_max == 1)
1621
png_warning(png_ptr, "No space in chunk cache for sPLT");
1622
png_crc_finish(png_ptr, length);
1628
if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1629
png_chunk_error(png_ptr, "missing IHDR");
1631
else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
1633
png_crc_finish(png_ptr, length);
1634
png_chunk_benign_error(png_ptr, "out of place");
1638
#ifdef PNG_MAX_MALLOC_64K
1639
if (length > 65535U)
1641
png_crc_finish(png_ptr, length);
1642
png_chunk_benign_error(png_ptr, "too large to fit in memory");
1647
buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
1650
png_crc_finish(png_ptr, length);
1651
png_chunk_benign_error(png_ptr, "out of memory");
1656
/* WARNING: this may break if size_t is less than 32 bits; it is assumed
1657
* that the PNG_MAX_MALLOC_64K test is enabled in this case, but this is a
1658
* potential breakage point if the types in pngconf.h aren't exactly right.
1660
png_crc_read(png_ptr, buffer, length);
1662
if (png_crc_finish(png_ptr, skip) != 0)
1667
for (entry_start = buffer; *entry_start; entry_start++)
1668
/* Empty loop to find end of name */ ;
1672
/* A sample depth should follow the separator, and we should be on it */
1673
if (entry_start > buffer + length - 2)
1675
png_warning(png_ptr, "malformed sPLT chunk");
1679
new_palette.depth = *entry_start++;
1680
entry_size = (new_palette.depth == 8 ? 6 : 10);
1681
/* This must fit in a png_uint_32 because it is derived from the original
1682
* chunk data length.
1684
data_length = length - (png_uint_32)(entry_start - buffer);
1686
/* Integrity-check the data length */
1687
if ((data_length % entry_size) != 0)
1689
png_warning(png_ptr, "sPLT chunk has bad length");
1693
dl = (png_int_32)(data_length / entry_size);
1694
max_dl = PNG_SIZE_MAX / (sizeof (png_sPLT_entry));
1698
png_warning(png_ptr, "sPLT chunk too long");
1702
new_palette.nentries = (png_int_32)(data_length / entry_size);
1704
new_palette.entries = (png_sPLT_entryp)png_malloc_warn(
1705
png_ptr, new_palette.nentries * (sizeof (png_sPLT_entry)));
1707
if (new_palette.entries == NULL)
1709
png_warning(png_ptr, "sPLT chunk requires too much memory");
1713
#ifdef PNG_POINTER_INDEXING_SUPPORTED
1714
for (i = 0; i < new_palette.nentries; i++)
1716
pp = new_palette.entries + i;
1718
if (new_palette.depth == 8)
1720
pp->red = *entry_start++;
1721
pp->green = *entry_start++;
1722
pp->blue = *entry_start++;
1723
pp->alpha = *entry_start++;
1728
pp->red = png_get_uint_16(entry_start); entry_start += 2;
1729
pp->green = png_get_uint_16(entry_start); entry_start += 2;
1730
pp->blue = png_get_uint_16(entry_start); entry_start += 2;
1731
pp->alpha = png_get_uint_16(entry_start); entry_start += 2;
1734
pp->frequency = png_get_uint_16(entry_start); entry_start += 2;
1737
pp = new_palette.entries;
1739
for (i = 0; i < new_palette.nentries; i++)
1742
if (new_palette.depth == 8)
1744
pp[i].red = *entry_start++;
1745
pp[i].green = *entry_start++;
1746
pp[i].blue = *entry_start++;
1747
pp[i].alpha = *entry_start++;
1752
pp[i].red = png_get_uint_16(entry_start); entry_start += 2;
1753
pp[i].green = png_get_uint_16(entry_start); entry_start += 2;
1754
pp[i].blue = png_get_uint_16(entry_start); entry_start += 2;
1755
pp[i].alpha = png_get_uint_16(entry_start); entry_start += 2;
1758
pp[i].frequency = png_get_uint_16(entry_start); entry_start += 2;
1762
/* Discard all chunk data except the name and stash that */
1763
new_palette.name = (png_charp)buffer;
1765
png_set_sPLT(png_ptr, info_ptr, &new_palette, 1);
1767
png_free(png_ptr, new_palette.entries);
1769
#endif /* READ_sPLT */
1771
#ifdef PNG_READ_tRNS_SUPPORTED
1773
png_handle_tRNS(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1775
png_byte readbuf[PNG_MAX_PALETTE_LENGTH];
1777
png_debug(1, "in png_handle_tRNS");
1779
if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1780
png_chunk_error(png_ptr, "missing IHDR");
1782
else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
1784
png_crc_finish(png_ptr, length);
1785
png_chunk_benign_error(png_ptr, "out of place");
1789
else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0)
1791
png_crc_finish(png_ptr, length);
1792
png_chunk_benign_error(png_ptr, "duplicate");
1796
if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
1802
png_crc_finish(png_ptr, length);
1803
png_chunk_benign_error(png_ptr, "invalid");
1807
png_crc_read(png_ptr, buf, 2);
1808
png_ptr->num_trans = 1;
1809
png_ptr->trans_color.gray = png_get_uint_16(buf);
1812
else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
1818
png_crc_finish(png_ptr, length);
1819
png_chunk_benign_error(png_ptr, "invalid");
1823
png_crc_read(png_ptr, buf, length);
1824
png_ptr->num_trans = 1;
1825
png_ptr->trans_color.red = png_get_uint_16(buf);
1826
png_ptr->trans_color.green = png_get_uint_16(buf + 2);
1827
png_ptr->trans_color.blue = png_get_uint_16(buf + 4);
1830
else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1832
if ((png_ptr->mode & PNG_HAVE_PLTE) == 0)
1834
/* TODO: is this actually an error in the ISO spec? */
1835
png_crc_finish(png_ptr, length);
1836
png_chunk_benign_error(png_ptr, "out of place");
1840
if (length > (unsigned int) png_ptr->num_palette ||
1841
length > (unsigned int) PNG_MAX_PALETTE_LENGTH ||
1844
png_crc_finish(png_ptr, length);
1845
png_chunk_benign_error(png_ptr, "invalid");
1849
png_crc_read(png_ptr, readbuf, length);
1850
png_ptr->num_trans = (png_uint_16)length;
1855
png_crc_finish(png_ptr, length);
1856
png_chunk_benign_error(png_ptr, "invalid with alpha channel");
1860
if (png_crc_finish(png_ptr, 0) != 0)
1862
png_ptr->num_trans = 0;
1866
/* TODO: this is a horrible side effect in the palette case because the
1867
* png_struct ends up with a pointer to the tRNS buffer owned by the
1868
* png_info. Fix this.
1870
png_set_tRNS(png_ptr, info_ptr, readbuf, png_ptr->num_trans,
1871
&(png_ptr->trans_color));
1875
#ifdef PNG_READ_bKGD_SUPPORTED
1877
png_handle_bKGD(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1879
unsigned int truelen;
1881
png_color_16 background;
1883
png_debug(1, "in png_handle_bKGD");
1885
if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1886
png_chunk_error(png_ptr, "missing IHDR");
1888
else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 ||
1889
(png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
1890
(png_ptr->mode & PNG_HAVE_PLTE) == 0))
1892
png_crc_finish(png_ptr, length);
1893
png_chunk_benign_error(png_ptr, "out of place");
1897
else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0)
1899
png_crc_finish(png_ptr, length);
1900
png_chunk_benign_error(png_ptr, "duplicate");
1904
if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1907
else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
1913
if (length != truelen)
1915
png_crc_finish(png_ptr, length);
1916
png_chunk_benign_error(png_ptr, "invalid");
1920
png_crc_read(png_ptr, buf, truelen);
1922
if (png_crc_finish(png_ptr, 0) != 0)
1925
/* We convert the index value into RGB components so that we can allow
1926
* arbitrary RGB values for background when we have transparency, and
1927
* so it is easy to determine the RGB values of the background color
1928
* from the info_ptr struct.
1930
if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1932
background.index = buf[0];
1934
if (info_ptr != NULL && info_ptr->num_palette != 0)
1936
if (buf[0] >= info_ptr->num_palette)
1938
png_chunk_benign_error(png_ptr, "invalid index");
1942
background.red = (png_uint_16)png_ptr->palette[buf[0]].red;
1943
background.green = (png_uint_16)png_ptr->palette[buf[0]].green;
1944
background.blue = (png_uint_16)png_ptr->palette[buf[0]].blue;
1948
background.red = background.green = background.blue = 0;
1950
background.gray = 0;
1953
else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0) /* GRAY */
1955
background.index = 0;
1959
background.gray = png_get_uint_16(buf);
1964
background.index = 0;
1965
background.red = png_get_uint_16(buf);
1966
background.green = png_get_uint_16(buf + 2);
1967
background.blue = png_get_uint_16(buf + 4);
1968
background.gray = 0;
1971
png_set_bKGD(png_ptr, info_ptr, &background);
1975
#ifdef PNG_READ_hIST_SUPPORTED
1977
png_handle_hIST(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1979
unsigned int num, i;
1980
png_uint_16 readbuf[PNG_MAX_PALETTE_LENGTH];
1982
png_debug(1, "in png_handle_hIST");
1984
if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1985
png_chunk_error(png_ptr, "missing IHDR");
1987
else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 ||
1988
(png_ptr->mode & PNG_HAVE_PLTE) == 0)
1990
png_crc_finish(png_ptr, length);
1991
png_chunk_benign_error(png_ptr, "out of place");
1995
else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0)
1997
png_crc_finish(png_ptr, length);
1998
png_chunk_benign_error(png_ptr, "duplicate");
2004
if (num != (unsigned int) png_ptr->num_palette ||
2005
num > (unsigned int) PNG_MAX_PALETTE_LENGTH)
2007
png_crc_finish(png_ptr, length);
2008
png_chunk_benign_error(png_ptr, "invalid");
2012
for (i = 0; i < num; i++)
2016
png_crc_read(png_ptr, buf, 2);
2017
readbuf[i] = png_get_uint_16(buf);
2020
if (png_crc_finish(png_ptr, 0) != 0)
2023
png_set_hIST(png_ptr, info_ptr, readbuf);
2027
#ifdef PNG_READ_pHYs_SUPPORTED
2029
png_handle_pHYs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2032
png_uint_32 res_x, res_y;
2035
png_debug(1, "in png_handle_pHYs");
2037
if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2038
png_chunk_error(png_ptr, "missing IHDR");
2040
else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2042
png_crc_finish(png_ptr, length);
2043
png_chunk_benign_error(png_ptr, "out of place");
2047
else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs) != 0)
2049
png_crc_finish(png_ptr, length);
2050
png_chunk_benign_error(png_ptr, "duplicate");
2056
png_crc_finish(png_ptr, length);
2057
png_chunk_benign_error(png_ptr, "invalid");
2061
png_crc_read(png_ptr, buf, 9);
2063
if (png_crc_finish(png_ptr, 0) != 0)
2066
res_x = png_get_uint_32(buf);
2067
res_y = png_get_uint_32(buf + 4);
2069
png_set_pHYs(png_ptr, info_ptr, res_x, res_y, unit_type);
2073
#ifdef PNG_READ_oFFs_SUPPORTED
2075
png_handle_oFFs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2078
png_int_32 offset_x, offset_y;
2081
png_debug(1, "in png_handle_oFFs");
2083
if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2084
png_chunk_error(png_ptr, "missing IHDR");
2086
else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2088
png_crc_finish(png_ptr, length);
2089
png_chunk_benign_error(png_ptr, "out of place");
2093
else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs) != 0)
2095
png_crc_finish(png_ptr, length);
2096
png_chunk_benign_error(png_ptr, "duplicate");
2102
png_crc_finish(png_ptr, length);
2103
png_chunk_benign_error(png_ptr, "invalid");
2107
png_crc_read(png_ptr, buf, 9);
2109
if (png_crc_finish(png_ptr, 0) != 0)
2112
offset_x = png_get_int_32(buf);
2113
offset_y = png_get_int_32(buf + 4);
2115
png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y, unit_type);
2119
#ifdef PNG_READ_pCAL_SUPPORTED
2120
/* Read the pCAL chunk (described in the PNG Extensions document) */
2122
png_handle_pCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2125
png_byte type, nparams;
2126
png_bytep buffer, buf, units, endptr;
2130
png_debug(1, "in png_handle_pCAL");
2132
if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2133
png_chunk_error(png_ptr, "missing IHDR");
2135
else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2137
png_crc_finish(png_ptr, length);
2138
png_chunk_benign_error(png_ptr, "out of place");
2142
else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL) != 0)
2144
png_crc_finish(png_ptr, length);
2145
png_chunk_benign_error(png_ptr, "duplicate");
2149
png_debug1(2, "Allocating and reading pCAL chunk data (%u bytes)",
2152
buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
2156
png_crc_finish(png_ptr, length);
2157
png_chunk_benign_error(png_ptr, "out of memory");
2161
png_crc_read(png_ptr, buffer, length);
2163
if (png_crc_finish(png_ptr, 0) != 0)
2166
buffer[length] = 0; /* Null terminate the last string */
2168
png_debug(3, "Finding end of pCAL purpose string");
2169
for (buf = buffer; *buf; buf++)
2172
endptr = buffer + length;
2174
/* We need to have at least 12 bytes after the purpose string
2175
* in order to get the parameter information.
2177
if (endptr <= buf + 12)
2179
png_chunk_benign_error(png_ptr, "invalid");
2183
png_debug(3, "Reading pCAL X0, X1, type, nparams, and units");
2184
X0 = png_get_int_32((png_bytep)buf+1);
2185
X1 = png_get_int_32((png_bytep)buf+5);
2190
png_debug(3, "Checking pCAL equation type and number of parameters");
2191
/* Check that we have the right number of parameters for known
2194
if ((type == PNG_EQUATION_LINEAR && nparams != 2) ||
2195
(type == PNG_EQUATION_BASE_E && nparams != 3) ||
2196
(type == PNG_EQUATION_ARBITRARY && nparams != 3) ||
2197
(type == PNG_EQUATION_HYPERBOLIC && nparams != 4))
2199
png_chunk_benign_error(png_ptr, "invalid parameter count");
2203
else if (type >= PNG_EQUATION_LAST)
2205
png_chunk_benign_error(png_ptr, "unrecognized equation type");
2208
for (buf = units; *buf; buf++)
2209
/* Empty loop to move past the units string. */ ;
2211
png_debug(3, "Allocating pCAL parameters array");
2213
params = png_voidcast(png_charpp, png_malloc_warn(png_ptr,
2214
nparams * (sizeof (png_charp))));
2218
png_chunk_benign_error(png_ptr, "out of memory");
2222
/* Get pointers to the start of each parameter string. */
2223
for (i = 0; i < nparams; i++)
2225
buf++; /* Skip the null string terminator from previous parameter. */
2227
png_debug1(3, "Reading pCAL parameter %d", i);
2229
for (params[i] = (png_charp)buf; buf <= endptr && *buf != 0; buf++)
2230
/* Empty loop to move past each parameter string */ ;
2232
/* Make sure we haven't run out of data yet */
2235
png_free(png_ptr, params);
2236
png_chunk_benign_error(png_ptr, "invalid data");
2241
png_set_pCAL(png_ptr, info_ptr, (png_charp)buffer, X0, X1, type, nparams,
2242
(png_charp)units, params);
2244
png_free(png_ptr, params);
2248
#ifdef PNG_READ_sCAL_SUPPORTED
2249
/* Read the sCAL chunk */
2251
png_handle_sCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2257
png_debug(1, "in png_handle_sCAL");
2259
if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2260
png_chunk_error(png_ptr, "missing IHDR");
2262
else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2264
png_crc_finish(png_ptr, length);
2265
png_chunk_benign_error(png_ptr, "out of place");
2269
else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sCAL) != 0)
2271
png_crc_finish(png_ptr, length);
2272
png_chunk_benign_error(png_ptr, "duplicate");
2276
/* Need unit type, width, \0, height: minimum 4 bytes */
2277
else if (length < 4)
2279
png_crc_finish(png_ptr, length);
2280
png_chunk_benign_error(png_ptr, "invalid");
2284
png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)",
2287
buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
2291
png_chunk_benign_error(png_ptr, "out of memory");
2292
png_crc_finish(png_ptr, length);
2296
png_crc_read(png_ptr, buffer, length);
2297
buffer[length] = 0; /* Null terminate the last string */
2299
if (png_crc_finish(png_ptr, 0) != 0)
2302
/* Validate the unit. */
2303
if (buffer[0] != 1 && buffer[0] != 2)
2305
png_chunk_benign_error(png_ptr, "invalid unit");
2309
/* Validate the ASCII numbers, need two ASCII numbers separated by
2310
* a '\0' and they need to fit exactly in the chunk data.
2315
if (png_check_fp_number((png_const_charp)buffer, length, &state, &i) == 0 ||
2316
i >= length || buffer[i++] != 0)
2317
png_chunk_benign_error(png_ptr, "bad width format");
2319
else if (PNG_FP_IS_POSITIVE(state) == 0)
2320
png_chunk_benign_error(png_ptr, "non-positive width");
2324
png_size_t heighti = i;
2327
if (png_check_fp_number((png_const_charp)buffer, length,
2328
&state, &i) == 0 || i != length)
2329
png_chunk_benign_error(png_ptr, "bad height format");
2331
else if (PNG_FP_IS_POSITIVE(state) == 0)
2332
png_chunk_benign_error(png_ptr, "non-positive height");
2335
/* This is the (only) success case. */
2336
png_set_sCAL_s(png_ptr, info_ptr, buffer[0],
2337
(png_charp)buffer+1, (png_charp)buffer+heighti);
2342
#ifdef PNG_READ_tIME_SUPPORTED
2344
png_handle_tIME(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2349
png_debug(1, "in png_handle_tIME");
2351
if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2352
png_chunk_error(png_ptr, "missing IHDR");
2354
else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME) != 0)
2356
png_crc_finish(png_ptr, length);
2357
png_chunk_benign_error(png_ptr, "duplicate");
2361
if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2362
png_ptr->mode |= PNG_AFTER_IDAT;
2366
png_crc_finish(png_ptr, length);
2367
png_chunk_benign_error(png_ptr, "invalid");
2371
png_crc_read(png_ptr, buf, 7);
2373
if (png_crc_finish(png_ptr, 0) != 0)
2376
mod_time.second = buf[6];
2377
mod_time.minute = buf[5];
2378
mod_time.hour = buf[4];
2379
mod_time.day = buf[3];
2380
mod_time.month = buf[2];
2381
mod_time.year = png_get_uint_16(buf);
2383
png_set_tIME(png_ptr, info_ptr, &mod_time);
2387
#ifdef PNG_READ_tEXt_SUPPORTED
2388
/* Note: this does not properly handle chunks that are > 64K under DOS */
2390
png_handle_tEXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2396
png_uint_32 skip = 0;
2398
png_debug(1, "in png_handle_tEXt");
2400
#ifdef PNG_USER_LIMITS_SUPPORTED
2401
if (png_ptr->user_chunk_cache_max != 0)
2403
if (png_ptr->user_chunk_cache_max == 1)
2405
png_crc_finish(png_ptr, length);
2409
if (--png_ptr->user_chunk_cache_max == 1)
2411
png_crc_finish(png_ptr, length);
2412
png_chunk_benign_error(png_ptr, "no space in chunk cache");
2418
if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2419
png_chunk_error(png_ptr, "missing IHDR");
2421
if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2422
png_ptr->mode |= PNG_AFTER_IDAT;
2424
#ifdef PNG_MAX_MALLOC_64K
2425
if (length > 65535U)
2427
png_crc_finish(png_ptr, length);
2428
png_chunk_benign_error(png_ptr, "too large to fit in memory");
2433
buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/);
2437
png_chunk_benign_error(png_ptr, "out of memory");
2441
png_crc_read(png_ptr, buffer, length);
2443
if (png_crc_finish(png_ptr, skip) != 0)
2446
key = (png_charp)buffer;
2449
for (text = key; *text; text++)
2450
/* Empty loop to find end of key */ ;
2452
if (text != key + length)
2455
text_info.compression = PNG_TEXT_COMPRESSION_NONE;
2456
text_info.key = key;
2457
text_info.lang = NULL;
2458
text_info.lang_key = NULL;
2459
text_info.itxt_length = 0;
2460
text_info.text = text;
2461
text_info.text_length = strlen(text);
2463
if (png_set_text_2(png_ptr, info_ptr, &text_info, 1) != 0)
2464
png_warning(png_ptr, "Insufficient memory to process text chunk");
2468
#ifdef PNG_READ_zTXt_SUPPORTED
2469
/* Note: this does not correctly handle chunks that are > 64K under DOS */
2471
png_handle_zTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2473
png_const_charp errmsg = NULL;
2475
png_uint_32 keyword_length;
2477
png_debug(1, "in png_handle_zTXt");
2479
#ifdef PNG_USER_LIMITS_SUPPORTED
2480
if (png_ptr->user_chunk_cache_max != 0)
2482
if (png_ptr->user_chunk_cache_max == 1)
2484
png_crc_finish(png_ptr, length);
2488
if (--png_ptr->user_chunk_cache_max == 1)
2490
png_crc_finish(png_ptr, length);
2491
png_chunk_benign_error(png_ptr, "no space in chunk cache");
2497
if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2498
png_chunk_error(png_ptr, "missing IHDR");
2500
if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2501
png_ptr->mode |= PNG_AFTER_IDAT;
2503
buffer = png_read_buffer(png_ptr, length, 2/*silent*/);
2507
png_crc_finish(png_ptr, length);
2508
png_chunk_benign_error(png_ptr, "out of memory");
2512
png_crc_read(png_ptr, buffer, length);
2514
if (png_crc_finish(png_ptr, 0) != 0)
2517
/* TODO: also check that the keyword contents match the spec! */
2518
for (keyword_length = 0;
2519
keyword_length < length && buffer[keyword_length] != 0;
2521
/* Empty loop to find end of name */ ;
2523
if (keyword_length > 79 || keyword_length < 1)
2524
errmsg = "bad keyword";
2526
/* zTXt must have some LZ data after the keyword, although it may expand to
2527
* zero bytes; we need a '\0' at the end of the keyword, the compression type
2530
else if (keyword_length + 3 > length)
2531
errmsg = "truncated";
2533
else if (buffer[keyword_length+1] != PNG_COMPRESSION_TYPE_BASE)
2534
errmsg = "unknown compression type";
2538
png_alloc_size_t uncompressed_length = PNG_SIZE_MAX;
2540
/* TODO: at present png_decompress_chunk imposes a single application
2541
* level memory limit, this should be split to different values for iCCP
2544
if (png_decompress_chunk(png_ptr, length, keyword_length+2,
2545
&uncompressed_length, 1/*terminate*/) == Z_STREAM_END)
2549
/* It worked; png_ptr->read_buffer now looks like a tEXt chunk except
2550
* for the extra compression type byte and the fact that it isn't
2551
* necessarily '\0' terminated.
2553
buffer = png_ptr->read_buffer;
2554
buffer[uncompressed_length+(keyword_length+2)] = 0;
2556
text.compression = PNG_TEXT_COMPRESSION_zTXt;
2557
text.key = (png_charp)buffer;
2558
text.text = (png_charp)(buffer + keyword_length+2);
2559
text.text_length = uncompressed_length;
2560
text.itxt_length = 0;
2562
text.lang_key = NULL;
2564
if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0)
2565
errmsg = "insufficient memory";
2569
errmsg = png_ptr->zstream.msg;
2573
png_chunk_benign_error(png_ptr, errmsg);
2577
#ifdef PNG_READ_iTXt_SUPPORTED
2578
/* Note: this does not correctly handle chunks that are > 64K under DOS */
2580
png_handle_iTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2582
png_const_charp errmsg = NULL;
2584
png_uint_32 prefix_length;
2586
png_debug(1, "in png_handle_iTXt");
2588
#ifdef PNG_USER_LIMITS_SUPPORTED
2589
if (png_ptr->user_chunk_cache_max != 0)
2591
if (png_ptr->user_chunk_cache_max == 1)
2593
png_crc_finish(png_ptr, length);
2597
if (--png_ptr->user_chunk_cache_max == 1)
2599
png_crc_finish(png_ptr, length);
2600
png_chunk_benign_error(png_ptr, "no space in chunk cache");
2606
if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2607
png_chunk_error(png_ptr, "missing IHDR");
2609
if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2610
png_ptr->mode |= PNG_AFTER_IDAT;
2612
buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/);
2616
png_crc_finish(png_ptr, length);
2617
png_chunk_benign_error(png_ptr, "out of memory");
2621
png_crc_read(png_ptr, buffer, length);
2623
if (png_crc_finish(png_ptr, 0) != 0)
2626
/* First the keyword. */
2627
for (prefix_length=0;
2628
prefix_length < length && buffer[prefix_length] != 0;
2632
/* Perform a basic check on the keyword length here. */
2633
if (prefix_length > 79 || prefix_length < 1)
2634
errmsg = "bad keyword";
2636
/* Expect keyword, compression flag, compression type, language, translated
2637
* keyword (both may be empty but are 0 terminated) then the text, which may
2640
else if (prefix_length + 5 > length)
2641
errmsg = "truncated";
2643
else if (buffer[prefix_length+1] == 0 ||
2644
(buffer[prefix_length+1] == 1 &&
2645
buffer[prefix_length+2] == PNG_COMPRESSION_TYPE_BASE))
2647
int compressed = buffer[prefix_length+1] != 0;
2648
png_uint_32 language_offset, translated_keyword_offset;
2649
png_alloc_size_t uncompressed_length = 0;
2651
/* Now the language tag */
2653
language_offset = prefix_length;
2655
for (; prefix_length < length && buffer[prefix_length] != 0;
2659
/* WARNING: the length may be invalid here, this is checked below. */
2660
translated_keyword_offset = ++prefix_length;
2662
for (; prefix_length < length && buffer[prefix_length] != 0;
2666
/* prefix_length should now be at the trailing '\0' of the translated
2667
* keyword, but it may already be over the end. None of this arithmetic
2668
* can overflow because chunks are at most 2^31 bytes long, but on 16-bit
2669
* systems the available allocation may overflow.
2673
if (compressed == 0 && prefix_length <= length)
2674
uncompressed_length = length - prefix_length;
2676
else if (compressed != 0 && prefix_length < length)
2678
uncompressed_length = PNG_SIZE_MAX;
2680
/* TODO: at present png_decompress_chunk imposes a single application
2681
* level memory limit, this should be split to different values for
2682
* iCCP and text chunks.
2684
if (png_decompress_chunk(png_ptr, length, prefix_length,
2685
&uncompressed_length, 1/*terminate*/) == Z_STREAM_END)
2686
buffer = png_ptr->read_buffer;
2689
errmsg = png_ptr->zstream.msg;
2693
errmsg = "truncated";
2699
buffer[uncompressed_length+prefix_length] = 0;
2701
if (compressed == 0)
2702
text.compression = PNG_ITXT_COMPRESSION_NONE;
2705
text.compression = PNG_ITXT_COMPRESSION_zTXt;
2707
text.key = (png_charp)buffer;
2708
text.lang = (png_charp)buffer + language_offset;
2709
text.lang_key = (png_charp)buffer + translated_keyword_offset;
2710
text.text = (png_charp)buffer + prefix_length;
2711
text.text_length = 0;
2712
text.itxt_length = uncompressed_length;
2714
if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0)
2715
errmsg = "insufficient memory";
2720
errmsg = "bad compression info";
2723
png_chunk_benign_error(png_ptr, errmsg);
2727
#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
2728
/* Utility function for png_handle_unknown; set up png_ptr::unknown_chunk */
2730
png_cache_unknown_chunk(png_structrp png_ptr, png_uint_32 length)
2732
png_alloc_size_t limit = PNG_SIZE_MAX;
2734
if (png_ptr->unknown_chunk.data != NULL)
2736
png_free(png_ptr, png_ptr->unknown_chunk.data);
2737
png_ptr->unknown_chunk.data = NULL;
2740
# ifdef PNG_SET_USER_LIMITS_SUPPORTED
2741
if (png_ptr->user_chunk_malloc_max > 0 &&
2742
png_ptr->user_chunk_malloc_max < limit)
2743
limit = png_ptr->user_chunk_malloc_max;
2745
# elif PNG_USER_CHUNK_MALLOC_MAX > 0
2746
if (PNG_USER_CHUNK_MALLOC_MAX < limit)
2747
limit = PNG_USER_CHUNK_MALLOC_MAX;
2750
if (length <= limit)
2752
PNG_CSTRING_FROM_CHUNK(png_ptr->unknown_chunk.name, png_ptr->chunk_name);
2753
/* The following is safe because of the PNG_SIZE_MAX init above */
2754
png_ptr->unknown_chunk.size = (png_size_t)length/*SAFE*/;
2755
/* 'mode' is a flag array, only the bottom four bits matter here */
2756
png_ptr->unknown_chunk.location = (png_byte)png_ptr->mode/*SAFE*/;
2759
png_ptr->unknown_chunk.data = NULL;
2763
/* Do a 'warn' here - it is handled below. */
2764
png_ptr->unknown_chunk.data = png_voidcast(png_bytep,
2765
png_malloc_warn(png_ptr, length));
2769
if (png_ptr->unknown_chunk.data == NULL && length > 0)
2771
/* This is benign because we clean up correctly */
2772
png_crc_finish(png_ptr, length);
2773
png_chunk_benign_error(png_ptr, "unknown chunk exceeds memory limits");
2780
png_crc_read(png_ptr, png_ptr->unknown_chunk.data, length);
2781
png_crc_finish(png_ptr, 0);
2785
#endif /* READ_UNKNOWN_CHUNKS */
2787
/* Handle an unknown, or known but disabled, chunk */
2789
png_handle_unknown(png_structrp png_ptr, png_inforp info_ptr,
2790
png_uint_32 length, int keep)
2792
int handled = 0; /* the chunk was handled */
2794
png_debug(1, "in png_handle_unknown");
2796
#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
2797
/* NOTE: this code is based on the code in libpng-1.4.12 except for fixing
2798
* the bug which meant that setting a non-default behavior for a specific
2799
* chunk would be ignored (the default was always used unless a user
2800
* callback was installed).
2802
* 'keep' is the value from the png_chunk_unknown_handling, the setting for
2803
* this specific chunk_name, if PNG_HANDLE_AS_UNKNOWN_SUPPORTED, if not it
2804
* will always be PNG_HANDLE_CHUNK_AS_DEFAULT and it needs to be set here.
2805
* This is just an optimization to avoid multiple calls to the lookup
2808
# ifndef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
2809
# ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
2810
keep = png_chunk_unknown_handling(png_ptr, png_ptr->chunk_name);
2814
/* One of the following methods will read the chunk or skip it (at least one
2815
* of these is always defined because this is the only way to switch on
2816
* PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
2818
# ifdef PNG_READ_USER_CHUNKS_SUPPORTED
2819
/* The user callback takes precedence over the chunk keep value, but the
2820
* keep value is still required to validate a save of a critical chunk.
2822
if (png_ptr->read_user_chunk_fn != NULL)
2824
if (png_cache_unknown_chunk(png_ptr, length) != 0)
2826
/* Callback to user unknown chunk handler */
2827
int ret = (*(png_ptr->read_user_chunk_fn))(png_ptr,
2828
&png_ptr->unknown_chunk);
2831
* negative: An error occurred; png_chunk_error will be called.
2832
* zero: The chunk was not handled, the chunk will be discarded
2833
* unless png_set_keep_unknown_chunks has been used to set
2834
* a 'keep' behavior for this particular chunk, in which
2835
* case that will be used. A critical chunk will cause an
2836
* error at this point unless it is to be saved.
2837
* positive: The chunk was handled, libpng will ignore/discard it.
2840
png_chunk_error(png_ptr, "error in user chunk");
2844
/* If the keep value is 'default' or 'never' override it, but
2845
* still error out on critical chunks unless the keep value is
2846
* 'always' While this is weird it is the behavior in 1.4.12.
2847
* A possible improvement would be to obey the value set for the
2848
* chunk, but this would be an API change that would probably
2849
* damage some applications.
2851
* The png_app_warning below catches the case that matters, where
2852
* the application has not set specific save or ignore for this
2853
* chunk or global save or ignore.
2855
if (keep < PNG_HANDLE_CHUNK_IF_SAFE)
2857
# ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
2858
if (png_ptr->unknown_default < PNG_HANDLE_CHUNK_IF_SAFE)
2860
png_chunk_warning(png_ptr, "Saving unknown chunk:");
2861
png_app_warning(png_ptr,
2862
"forcing save of an unhandled chunk;"
2863
" please call png_set_keep_unknown_chunks");
2864
/* with keep = PNG_HANDLE_CHUNK_IF_SAFE */
2867
keep = PNG_HANDLE_CHUNK_IF_SAFE;
2871
else /* chunk was handled */
2874
/* Critical chunks can be safely discarded at this point. */
2875
keep = PNG_HANDLE_CHUNK_NEVER;
2880
keep = PNG_HANDLE_CHUNK_NEVER; /* insufficient memory */
2884
/* Use the SAVE_UNKNOWN_CHUNKS code or skip the chunk */
2885
# endif /* READ_USER_CHUNKS */
2887
# ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
2889
/* keep is currently just the per-chunk setting, if there was no
2890
* setting change it to the global default now (not that this may
2891
* still be AS_DEFAULT) then obtain the cache of the chunk if required,
2892
* if not simply skip the chunk.
2894
if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT)
2895
keep = png_ptr->unknown_default;
2897
if (keep == PNG_HANDLE_CHUNK_ALWAYS ||
2898
(keep == PNG_HANDLE_CHUNK_IF_SAFE &&
2899
PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)))
2901
if (png_cache_unknown_chunk(png_ptr, length) == 0)
2902
keep = PNG_HANDLE_CHUNK_NEVER;
2906
png_crc_finish(png_ptr, length);
2909
# ifndef PNG_READ_USER_CHUNKS_SUPPORTED
2910
# error no method to support READ_UNKNOWN_CHUNKS
2914
/* If here there is no read callback pointer set and no support is
2915
* compiled in to just save the unknown chunks, so simply skip this
2916
* chunk. If 'keep' is something other than AS_DEFAULT or NEVER then
2917
* the app has erroneously asked for unknown chunk saving when there
2920
if (keep > PNG_HANDLE_CHUNK_NEVER)
2921
png_app_error(png_ptr, "no unknown chunk support available");
2923
png_crc_finish(png_ptr, length);
2927
# ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
2928
/* Now store the chunk in the chunk list if appropriate, and if the limits
2931
if (keep == PNG_HANDLE_CHUNK_ALWAYS ||
2932
(keep == PNG_HANDLE_CHUNK_IF_SAFE &&
2933
PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)))
2935
# ifdef PNG_USER_LIMITS_SUPPORTED
2936
switch (png_ptr->user_chunk_cache_max)
2939
png_ptr->user_chunk_cache_max = 1;
2940
png_chunk_benign_error(png_ptr, "no space in chunk cache");
2943
/* NOTE: prior to 1.6.0 this case resulted in an unknown critical
2944
* chunk being skipped, now there will be a hard error below.
2948
default: /* not at limit */
2949
--(png_ptr->user_chunk_cache_max);
2951
case 0: /* no limit */
2952
# endif /* USER_LIMITS */
2953
/* Here when the limit isn't reached or when limits are compiled
2954
* out; store the chunk.
2956
png_set_unknown_chunks(png_ptr, info_ptr,
2957
&png_ptr->unknown_chunk, 1);
2959
# ifdef PNG_USER_LIMITS_SUPPORTED
2964
# else /* no store support: the chunk must be handled by the user callback */
2965
PNG_UNUSED(info_ptr)
2968
/* Regardless of the error handling below the cached data (if any) can be
2969
* freed now. Notice that the data is not freed if there is a png_error, but
2970
* it will be freed by destroy_read_struct.
2972
if (png_ptr->unknown_chunk.data != NULL)
2973
png_free(png_ptr, png_ptr->unknown_chunk.data);
2974
png_ptr->unknown_chunk.data = NULL;
2976
#else /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */
2977
/* There is no support to read an unknown chunk, so just skip it. */
2978
png_crc_finish(png_ptr, length);
2979
PNG_UNUSED(info_ptr)
2981
#endif /* !READ_UNKNOWN_CHUNKS */
2983
/* Check for unhandled critical chunks */
2984
if (handled == 0 && PNG_CHUNK_CRITICAL(png_ptr->chunk_name))
2985
png_chunk_error(png_ptr, "unhandled critical chunk");
2988
/* This function is called to verify that a chunk name is valid.
2989
* This function can't have the "critical chunk check" incorporated
2990
* into it, since in the future we will need to be able to call user
2991
* functions to handle unknown critical chunks after we check that
2992
* the chunk name itself is valid.
2995
/* Bit hacking: the test for an invalid byte in the 4 byte chunk name is:
2997
* ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
3001
png_check_chunk_name(png_structrp png_ptr, png_uint_32 chunk_name)
3005
png_debug(1, "in png_check_chunk_name");
3007
for (i=1; i<=4; ++i)
3009
int c = chunk_name & 0xff;
3011
if (c < 65 || c > 122 || (c > 90 && c < 97))
3012
png_chunk_error(png_ptr, "invalid chunk type");
3018
/* Combines the row recently read in with the existing pixels in the row. This
3019
* routine takes care of alpha and transparency if requested. This routine also
3020
* handles the two methods of progressive display of interlaced images,
3021
* depending on the 'display' value; if 'display' is true then the whole row
3022
* (dp) is filled from the start by replicating the available pixels. If
3023
* 'display' is false only those pixels present in the pass are filled in.
3026
png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display)
3028
unsigned int pixel_depth = png_ptr->transformed_pixel_depth;
3029
png_const_bytep sp = png_ptr->row_buf + 1;
3030
png_alloc_size_t row_width = png_ptr->width;
3031
unsigned int pass = png_ptr->pass;
3032
png_bytep end_ptr = 0;
3033
png_byte end_byte = 0;
3034
unsigned int end_mask;
3036
png_debug(1, "in png_combine_row");
3038
/* Added in 1.5.6: it should not be possible to enter this routine until at
3039
* least one row has been read from the PNG data and transformed.
3041
if (pixel_depth == 0)
3042
png_error(png_ptr, "internal row logic error");
3044
/* Added in 1.5.4: the pixel depth should match the information returned by
3045
* any call to png_read_update_info at this point. Do not continue if we got
3048
if (png_ptr->info_rowbytes != 0 && png_ptr->info_rowbytes !=
3049
PNG_ROWBYTES(pixel_depth, row_width))
3050
png_error(png_ptr, "internal row size calculation error");
3052
/* Don't expect this to ever happen: */
3054
png_error(png_ptr, "internal row width error");
3056
/* Preserve the last byte in cases where only part of it will be overwritten,
3057
* the multiply below may overflow, we don't care because ANSI-C guarantees
3058
* we get the low bits.
3060
end_mask = (pixel_depth * row_width) & 7;
3063
/* end_ptr == NULL is a flag to say do nothing */
3064
end_ptr = dp + PNG_ROWBYTES(pixel_depth, row_width) - 1;
3065
end_byte = *end_ptr;
3066
# ifdef PNG_READ_PACKSWAP_SUPPORTED
3067
if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
3068
/* little-endian byte */
3069
end_mask = 0xff << end_mask;
3071
else /* big-endian byte */
3073
end_mask = 0xff >> end_mask;
3074
/* end_mask is now the bits to *keep* from the destination row */
3077
/* For non-interlaced images this reduces to a memcpy(). A memcpy()
3078
* will also happen if interlacing isn't supported or if the application
3079
* does not call png_set_interlace_handling(). In the latter cases the
3080
* caller just gets a sequence of the unexpanded rows from each interlace
3083
#ifdef PNG_READ_INTERLACING_SUPPORTED
3084
if (png_ptr->interlaced != 0 &&
3085
(png_ptr->transformations & PNG_INTERLACE) != 0 &&
3086
pass < 6 && (display == 0 ||
3087
/* The following copies everything for 'display' on passes 0, 2 and 4. */
3088
(display == 1 && (pass & 1) != 0)))
3090
/* Narrow images may have no bits in a pass; the caller should handle
3091
* this, but this test is cheap:
3093
if (row_width <= PNG_PASS_START_COL(pass))
3096
if (pixel_depth < 8)
3098
/* For pixel depths up to 4 bpp the 8-pixel mask can be expanded to fit
3099
* into 32 bits, then a single loop over the bytes using the four byte
3100
* values in the 32-bit mask can be used. For the 'display' option the
3101
* expanded mask may also not require any masking within a byte. To
3102
* make this work the PACKSWAP option must be taken into account - it
3103
* simply requires the pixels to be reversed in each byte.
3105
* The 'regular' case requires a mask for each of the first 6 passes,
3106
* the 'display' case does a copy for the even passes in the range
3107
* 0..6. This has already been handled in the test above.
3109
* The masks are arranged as four bytes with the first byte to use in
3110
* the lowest bits (little-endian) regardless of the order (PACKSWAP or
3111
* not) of the pixels in each byte.
3113
* NOTE: the whole of this logic depends on the caller of this function
3114
* only calling it on rows appropriate to the pass. This function only
3115
* understands the 'x' logic; the 'y' logic is handled by the caller.
3117
* The following defines allow generation of compile time constant bit
3118
* masks for each pixel depth and each possibility of swapped or not
3119
* swapped bytes. Pass 'p' is in the range 0..6; 'x', a pixel index,
3120
* is in the range 0..7; and the result is 1 if the pixel is to be
3121
* copied in the pass, 0 if not. 'S' is for the sparkle method, 'B'
3122
* for the block method.
3124
* With some compilers a compile time expression of the general form:
3126
* (shift >= 32) ? (a >> (shift-32)) : (b >> shift)
3128
* Produces warnings with values of 'shift' in the range 33 to 63
3129
* because the right hand side of the ?: expression is evaluated by
3130
* the compiler even though it isn't used. Microsoft Visual C (various
3131
* versions) and the Intel C compiler are known to do this. To avoid
3132
* this the following macros are used in 1.5.6. This is a temporary
3133
* solution to avoid destabilizing the code during the release process.
3135
# if PNG_USE_COMPILE_TIME_MASKS
3136
# define PNG_LSR(x,s) ((x)>>((s) & 0x1f))
3137
# define PNG_LSL(x,s) ((x)<<((s) & 0x1f))
3139
# define PNG_LSR(x,s) ((x)>>(s))
3140
# define PNG_LSL(x,s) ((x)<<(s))
3142
# define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\
3143
PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1)
3144
# define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\
3145
PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1)
3147
/* Return a mask for pass 'p' pixel 'x' at depth 'd'. The mask is
3148
* little endian - the first pixel is at bit 0 - however the extra
3149
* parameter 's' can be set to cause the mask position to be swapped
3150
* within each byte, to match the PNG format. This is done by XOR of
3151
* the shift with 7, 6 or 4 for bit depths 1, 2 and 4.
3153
# define PIXEL_MASK(p,x,d,s) \
3154
(PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0))))
3156
/* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask.
3158
# define S_MASKx(p,x,d,s) (S_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
3159
# define B_MASKx(p,x,d,s) (B_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
3161
/* Combine 8 of these to get the full mask. For the 1-bpp and 2-bpp
3162
* cases the result needs replicating, for the 4-bpp case the above
3163
* generates a full 32 bits.
3165
# define MASK_EXPAND(m,d) ((m)*((d)==1?0x01010101:((d)==2?0x00010001:1)))
3167
# define S_MASK(p,d,s) MASK_EXPAND(S_MASKx(p,0,d,s) + S_MASKx(p,1,d,s) +\
3168
S_MASKx(p,2,d,s) + S_MASKx(p,3,d,s) + S_MASKx(p,4,d,s) +\
3169
S_MASKx(p,5,d,s) + S_MASKx(p,6,d,s) + S_MASKx(p,7,d,s), d)
3171
# define B_MASK(p,d,s) MASK_EXPAND(B_MASKx(p,0,d,s) + B_MASKx(p,1,d,s) +\
3172
B_MASKx(p,2,d,s) + B_MASKx(p,3,d,s) + B_MASKx(p,4,d,s) +\
3173
B_MASKx(p,5,d,s) + B_MASKx(p,6,d,s) + B_MASKx(p,7,d,s), d)
3175
#if PNG_USE_COMPILE_TIME_MASKS
3176
/* Utility macros to construct all the masks for a depth/swap
3177
* combination. The 's' parameter says whether the format is PNG
3178
* (big endian bytes) or not. Only the three odd-numbered passes are
3179
* required for the display/block algorithm.
3181
# define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\
3182
S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) }
3184
# define B_MASKS(d,s) { B_MASK(1,d,s), B_MASK(3,d,s), B_MASK(5,d,s) }
3186
# define DEPTH_INDEX(d) ((d)==1?0:((d)==2?1:2))
3188
/* Hence the pre-compiled masks indexed by PACKSWAP (or not), depth and
3191
static PNG_CONST png_uint_32 row_mask[2/*PACKSWAP*/][3/*depth*/][6] =
3193
/* Little-endian byte masks for PACKSWAP */
3194
{ S_MASKS(1,0), S_MASKS(2,0), S_MASKS(4,0) },
3195
/* Normal (big-endian byte) masks - PNG format */
3196
{ S_MASKS(1,1), S_MASKS(2,1), S_MASKS(4,1) }
3199
/* display_mask has only three entries for the odd passes, so index by
3202
static PNG_CONST png_uint_32 display_mask[2][3][3] =
3204
/* Little-endian byte masks for PACKSWAP */
3205
{ B_MASKS(1,0), B_MASKS(2,0), B_MASKS(4,0) },
3206
/* Normal (big-endian byte) masks - PNG format */
3207
{ B_MASKS(1,1), B_MASKS(2,1), B_MASKS(4,1) }
3210
# define MASK(pass,depth,display,png)\
3211
((display)?display_mask[png][DEPTH_INDEX(depth)][pass>>1]:\
3212
row_mask[png][DEPTH_INDEX(depth)][pass])
3214
#else /* !PNG_USE_COMPILE_TIME_MASKS */
3215
/* This is the runtime alternative: it seems unlikely that this will
3216
* ever be either smaller or faster than the compile time approach.
3218
# define MASK(pass,depth,display,png)\
3219
((display)?B_MASK(pass,depth,png):S_MASK(pass,depth,png))
3220
#endif /* !USE_COMPILE_TIME_MASKS */
3222
/* Use the appropriate mask to copy the required bits. In some cases
3223
* the byte mask will be 0 or 0xff; optimize these cases. row_width is
3224
* the number of pixels, but the code copies bytes, so it is necessary
3225
* to special case the end.
3227
png_uint_32 pixels_per_byte = 8 / pixel_depth;
3230
# ifdef PNG_READ_PACKSWAP_SUPPORTED
3231
if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
3232
mask = MASK(pass, pixel_depth, display, 0);
3236
mask = MASK(pass, pixel_depth, display, 1);
3242
/* It doesn't matter in the following if png_uint_32 has more than
3243
* 32 bits because the high bits always match those in m<<24; it is,
3244
* however, essential to use OR here, not +, because of this.
3247
mask = (m >> 8) | (m << 24); /* rotate right to good compilers */
3250
if (m != 0) /* something to copy */
3253
*dp = (png_byte)((*dp & ~m) | (*sp & m));
3258
/* NOTE: this may overwrite the last byte with garbage if the image
3259
* is not an exact number of bytes wide; libpng has always done
3262
if (row_width <= pixels_per_byte)
3263
break; /* May need to restore part of the last byte */
3265
row_width -= pixels_per_byte;
3271
else /* pixel_depth >= 8 */
3273
unsigned int bytes_to_copy, bytes_to_jump;
3275
/* Validate the depth - it must be a multiple of 8 */
3276
if (pixel_depth & 7)
3277
png_error(png_ptr, "invalid user transform pixel depth");
3279
pixel_depth >>= 3; /* now in bytes */
3280
row_width *= pixel_depth;
3282
/* Regardless of pass number the Adam 7 interlace always results in a
3283
* fixed number of pixels to copy then to skip. There may be a
3284
* different number of pixels to skip at the start though.
3287
unsigned int offset = PNG_PASS_START_COL(pass) * pixel_depth;
3289
row_width -= offset;
3294
/* Work out the bytes to copy. */
3297
/* When doing the 'block' algorithm the pixel in the pass gets
3298
* replicated to adjacent pixels. This is why the even (0,2,4,6)
3299
* passes are skipped above - the entire expanded row is copied.
3301
bytes_to_copy = (1<<((6-pass)>>1)) * pixel_depth;
3303
/* But don't allow this number to exceed the actual row width. */
3304
if (bytes_to_copy > row_width)
3305
bytes_to_copy = (unsigned int)/*SAFE*/row_width;
3308
else /* normal row; Adam7 only ever gives us one pixel to copy. */
3309
bytes_to_copy = pixel_depth;
3311
/* In Adam7 there is a constant offset between where the pixels go. */
3312
bytes_to_jump = PNG_PASS_COL_OFFSET(pass) * pixel_depth;
3314
/* And simply copy these bytes. Some optimization is possible here,
3315
* depending on the value of 'bytes_to_copy'. Special case the low
3316
* byte counts, which we know to be frequent.
3318
* Notice that these cases all 'return' rather than 'break' - this
3319
* avoids an unnecessary test on whether to restore the last byte
3322
switch (bytes_to_copy)
3329
if (row_width <= bytes_to_jump)
3332
dp += bytes_to_jump;
3333
sp += bytes_to_jump;
3334
row_width -= bytes_to_jump;
3338
/* There is a possibility of a partial copy at the end here; this
3339
* slows the code down somewhat.
3343
dp[0] = sp[0], dp[1] = sp[1];
3345
if (row_width <= bytes_to_jump)
3348
sp += bytes_to_jump;
3349
dp += bytes_to_jump;
3350
row_width -= bytes_to_jump;
3352
while (row_width > 1);
3354
/* And there can only be one byte left at this point: */
3359
/* This can only be the RGB case, so each copy is exactly one
3360
* pixel and it is not necessary to check for a partial copy.
3364
dp[0] = sp[0], dp[1] = sp[1], dp[2] = sp[2];
3366
if (row_width <= bytes_to_jump)
3369
sp += bytes_to_jump;
3370
dp += bytes_to_jump;
3371
row_width -= bytes_to_jump;
3375
#if PNG_ALIGN_TYPE != PNG_ALIGN_NONE
3376
/* Check for double byte alignment and, if possible, use a
3377
* 16-bit copy. Don't attempt this for narrow images - ones that
3378
* are less than an interlace panel wide. Don't attempt it for
3379
* wide bytes_to_copy either - use the memcpy there.
3381
if (bytes_to_copy < 16 /*else use memcpy*/ &&
3382
png_isaligned(dp, png_uint_16) &&
3383
png_isaligned(sp, png_uint_16) &&
3384
bytes_to_copy % (sizeof (png_uint_16)) == 0 &&
3385
bytes_to_jump % (sizeof (png_uint_16)) == 0)
3387
/* Everything is aligned for png_uint_16 copies, but try for
3388
* png_uint_32 first.
3390
if (png_isaligned(dp, png_uint_32) != 0 &&
3391
png_isaligned(sp, png_uint_32) != 0 &&
3392
bytes_to_copy % (sizeof (png_uint_32)) == 0 &&
3393
bytes_to_jump % (sizeof (png_uint_32)) == 0)
3395
png_uint_32p dp32 = png_aligncast(png_uint_32p,dp);
3396
png_const_uint_32p sp32 = png_aligncastconst(
3397
png_const_uint_32p, sp);
3398
size_t skip = (bytes_to_jump-bytes_to_copy) /
3399
(sizeof (png_uint_32));
3403
size_t c = bytes_to_copy;
3407
c -= (sizeof (png_uint_32));
3411
if (row_width <= bytes_to_jump)
3416
row_width -= bytes_to_jump;
3418
while (bytes_to_copy <= row_width);
3420
/* Get to here when the row_width truncates the final copy.
3421
* There will be 1-3 bytes left to copy, so don't try the
3422
* 16-bit loop below.
3424
dp = (png_bytep)dp32;
3425
sp = (png_const_bytep)sp32;
3428
while (--row_width > 0);
3432
/* Else do it in 16-bit quantities, but only if the size is
3437
png_uint_16p dp16 = png_aligncast(png_uint_16p, dp);
3438
png_const_uint_16p sp16 = png_aligncastconst(
3439
png_const_uint_16p, sp);
3440
size_t skip = (bytes_to_jump-bytes_to_copy) /
3441
(sizeof (png_uint_16));
3445
size_t c = bytes_to_copy;
3449
c -= (sizeof (png_uint_16));
3453
if (row_width <= bytes_to_jump)
3458
row_width -= bytes_to_jump;
3460
while (bytes_to_copy <= row_width);
3462
/* End of row - 1 byte left, bytes_to_copy > row_width: */
3463
dp = (png_bytep)dp16;
3464
sp = (png_const_bytep)sp16;
3467
while (--row_width > 0);
3471
#endif /* ALIGN_TYPE code */
3473
/* The true default - use a memcpy: */
3476
memcpy(dp, sp, bytes_to_copy);
3478
if (row_width <= bytes_to_jump)
3481
sp += bytes_to_jump;
3482
dp += bytes_to_jump;
3483
row_width -= bytes_to_jump;
3484
if (bytes_to_copy > row_width)
3485
bytes_to_copy = (unsigned int)/*SAFE*/row_width;
3490
} /* pixel_depth >= 8 */
3492
/* Here if pixel_depth < 8 to check 'end_ptr' below. */
3495
#endif /* READ_INTERLACING */
3497
/* If here then the switch above wasn't used so just memcpy the whole row
3498
* from the temporary row buffer (notice that this overwrites the end of the
3499
* destination row if it is a partial byte.)
3501
memcpy(dp, sp, PNG_ROWBYTES(pixel_depth, row_width));
3503
/* Restore the overwritten bits from the last byte if necessary. */
3504
if (end_ptr != NULL)
3505
*end_ptr = (png_byte)((end_byte & end_mask) | (*end_ptr & ~end_mask));
3508
#ifdef PNG_READ_INTERLACING_SUPPORTED
3510
png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
3511
png_uint_32 transformations /* Because these may affect the byte layout */)
3513
/* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
3514
/* Offset to next interlace block */
3515
static PNG_CONST int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
3517
png_debug(1, "in png_do_read_interlace");
3518
if (row != NULL && row_info != NULL)
3520
png_uint_32 final_width;
3522
final_width = row_info->width * png_pass_inc[pass];
3524
switch (row_info->pixel_depth)
3528
png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 3);
3529
png_bytep dp = row + (png_size_t)((final_width - 1) >> 3);
3531
int s_start, s_end, s_inc;
3532
int jstop = png_pass_inc[pass];
3537
#ifdef PNG_READ_PACKSWAP_SUPPORTED
3538
if ((transformations & PNG_PACKSWAP) != 0)
3540
sshift = (int)((row_info->width + 7) & 0x07);
3541
dshift = (int)((final_width + 7) & 0x07);
3550
sshift = 7 - (int)((row_info->width + 7) & 0x07);
3551
dshift = 7 - (int)((final_width + 7) & 0x07);
3557
for (i = 0; i < row_info->width; i++)
3559
v = (png_byte)((*sp >> sshift) & 0x01);
3560
for (j = 0; j < jstop; j++)
3562
unsigned int tmp = *dp & (0x7f7f >> (7 - dshift));
3564
*dp = (png_byte)(tmp & 0xff);
3566
if (dshift == s_end)
3576
if (sshift == s_end)
3590
png_bytep sp = row + (png_uint_32)((row_info->width - 1) >> 2);
3591
png_bytep dp = row + (png_uint_32)((final_width - 1) >> 2);
3593
int s_start, s_end, s_inc;
3594
int jstop = png_pass_inc[pass];
3597
#ifdef PNG_READ_PACKSWAP_SUPPORTED
3598
if ((transformations & PNG_PACKSWAP) != 0)
3600
sshift = (int)(((row_info->width + 3) & 0x03) << 1);
3601
dshift = (int)(((final_width + 3) & 0x03) << 1);
3610
sshift = (int)((3 - ((row_info->width + 3) & 0x03)) << 1);
3611
dshift = (int)((3 - ((final_width + 3) & 0x03)) << 1);
3617
for (i = 0; i < row_info->width; i++)
3622
v = (png_byte)((*sp >> sshift) & 0x03);
3623
for (j = 0; j < jstop; j++)
3625
unsigned int tmp = *dp & (0x3f3f >> (6 - dshift));
3627
*dp = (png_byte)(tmp & 0xff);
3629
if (dshift == s_end)
3639
if (sshift == s_end)
3653
png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 1);
3654
png_bytep dp = row + (png_size_t)((final_width - 1) >> 1);
3656
int s_start, s_end, s_inc;
3658
int jstop = png_pass_inc[pass];
3660
#ifdef PNG_READ_PACKSWAP_SUPPORTED
3661
if ((transformations & PNG_PACKSWAP) != 0)
3663
sshift = (int)(((row_info->width + 1) & 0x01) << 2);
3664
dshift = (int)(((final_width + 1) & 0x01) << 2);
3673
sshift = (int)((1 - ((row_info->width + 1) & 0x01)) << 2);
3674
dshift = (int)((1 - ((final_width + 1) & 0x01)) << 2);
3680
for (i = 0; i < row_info->width; i++)
3682
png_byte v = (png_byte)((*sp >> sshift) & 0x0f);
3685
for (j = 0; j < jstop; j++)
3687
unsigned int tmp = *dp & (0xf0f >> (4 - dshift));
3689
*dp = (png_byte)(tmp & 0xff);
3691
if (dshift == s_end)
3701
if (sshift == s_end)
3715
png_size_t pixel_bytes = (row_info->pixel_depth >> 3);
3717
png_bytep sp = row + (png_size_t)(row_info->width - 1)
3720
png_bytep dp = row + (png_size_t)(final_width - 1) * pixel_bytes;
3722
int jstop = png_pass_inc[pass];
3725
for (i = 0; i < row_info->width; i++)
3727
png_byte v[8]; /* SAFE; pixel_depth does not exceed 64 */
3730
memcpy(v, sp, pixel_bytes);
3732
for (j = 0; j < jstop; j++)
3734
memcpy(dp, v, pixel_bytes);
3744
row_info->width = final_width;
3745
row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, final_width);
3747
#ifndef PNG_READ_PACKSWAP_SUPPORTED
3748
PNG_UNUSED(transformations) /* Silence compiler warning */
3751
#endif /* READ_INTERLACING */
3754
png_read_filter_row_sub(png_row_infop row_info, png_bytep row,
3755
png_const_bytep prev_row)
3758
png_size_t istop = row_info->rowbytes;
3759
unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
3760
png_bytep rp = row + bpp;
3762
PNG_UNUSED(prev_row)
3764
for (i = bpp; i < istop; i++)
3766
*rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
3772
png_read_filter_row_up(png_row_infop row_info, png_bytep row,
3773
png_const_bytep prev_row)
3776
png_size_t istop = row_info->rowbytes;
3778
png_const_bytep pp = prev_row;
3780
for (i = 0; i < istop; i++)
3782
*rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
3788
png_read_filter_row_avg(png_row_infop row_info, png_bytep row,
3789
png_const_bytep prev_row)
3793
png_const_bytep pp = prev_row;
3794
unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
3795
png_size_t istop = row_info->rowbytes - bpp;
3797
for (i = 0; i < bpp; i++)
3799
*rp = (png_byte)(((int)(*rp) +
3800
((int)(*pp++) / 2 )) & 0xff);
3805
for (i = 0; i < istop; i++)
3807
*rp = (png_byte)(((int)(*rp) +
3808
(int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
3815
png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info, png_bytep row,
3816
png_const_bytep prev_row)
3818
png_bytep rp_end = row + row_info->rowbytes;
3821
/* First pixel/byte */
3824
*row++ = (png_byte)a;
3827
while (row < rp_end)
3829
int b, pa, pb, pc, p;
3831
a &= 0xff; /* From previous iteration or start */
3842
pa = p < 0 ? -p : p;
3843
pb = pc < 0 ? -pc : pc;
3844
pc = (p + pc) < 0 ? -(p + pc) : p + pc;
3847
/* Find the best predictor, the least of pa, pb, pc favoring the earlier
3848
* ones in the case of a tie.
3850
if (pb < pa) pa = pb, a = b;
3853
/* Calculate the current pixel in a, and move the previous row pixel to c
3854
* for the next time round the loop
3858
*row++ = (png_byte)a;
3863
png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row,
3864
png_const_bytep prev_row)
3866
int bpp = (row_info->pixel_depth + 7) >> 3;
3867
png_bytep rp_end = row + bpp;
3869
/* Process the first pixel in the row completely (this is the same as 'up'
3870
* because there is only one candidate predictor for the first row).
3872
while (row < rp_end)
3874
int a = *row + *prev_row++;
3875
*row++ = (png_byte)a;
3879
rp_end += row_info->rowbytes - bpp;
3881
while (row < rp_end)
3883
int a, b, c, pa, pb, pc, p;
3885
c = *(prev_row - bpp);
3897
pa = p < 0 ? -p : p;
3898
pb = pc < 0 ? -pc : pc;
3899
pc = (p + pc) < 0 ? -(p + pc) : p + pc;
3902
if (pb < pa) pa = pb, a = b;
3906
*row++ = (png_byte)a;
3911
png_init_filter_functions(png_structrp pp)
3912
/* This function is called once for every PNG image (except for PNG images
3913
* that only use PNG_FILTER_VALUE_NONE for all rows) to set the
3914
* implementations required to reverse the filtering of PNG rows. Reversing
3915
* the filter is the first transformation performed on the row data. It is
3916
* performed in place, therefore an implementation can be selected based on
3917
* the image pixel format. If the implementation depends on image width then
3918
* take care to ensure that it works correctly if the image is interlaced -
3919
* interlacing causes the actual row width to vary.
3922
unsigned int bpp = (pp->pixel_depth + 7) >> 3;
3924
pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub;
3925
pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up;
3926
pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg;
3928
pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
3929
png_read_filter_row_paeth_1byte_pixel;
3931
pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
3932
png_read_filter_row_paeth_multibyte_pixel;
3934
#ifdef PNG_FILTER_OPTIMIZATIONS
3935
/* To use this define PNG_FILTER_OPTIMIZATIONS as the name of a function to
3936
* call to install hardware optimizations for the above functions; simply
3937
* replace whatever elements of the pp->read_filter[] array with a hardware
3938
* specific (or, for that matter, generic) optimization.
3940
* To see an example of this examine what configure.ac does when
3941
* --enable-arm-neon is specified on the command line.
3943
PNG_FILTER_OPTIMIZATIONS(pp, bpp);
3948
png_read_filter_row(png_structrp pp, png_row_infop row_info, png_bytep row,
3949
png_const_bytep prev_row, int filter)
3951
/* OPTIMIZATION: DO NOT MODIFY THIS FUNCTION, instead #define
3952
* PNG_FILTER_OPTIMIZATIONS to a function that overrides the generic
3953
* implementations. See png_init_filter_functions above.
3955
if (filter > PNG_FILTER_VALUE_NONE && filter < PNG_FILTER_VALUE_LAST)
3957
if (pp->read_filter[0] == NULL)
3958
png_init_filter_functions(pp);
3960
pp->read_filter[filter-1](row_info, row, prev_row);
3964
#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
3966
png_read_IDAT_data(png_structrp png_ptr, png_bytep output,
3967
png_alloc_size_t avail_out)
3969
/* Loop reading IDATs and decompressing the result into output[avail_out] */
3970
png_ptr->zstream.next_out = output;
3971
png_ptr->zstream.avail_out = 0; /* safety: set below */
3979
png_byte tmpbuf[PNG_INFLATE_BUF_SIZE];
3981
if (png_ptr->zstream.avail_in == 0)
3986
while (png_ptr->idat_size == 0)
3988
png_crc_finish(png_ptr, 0);
3990
png_ptr->idat_size = png_read_chunk_header(png_ptr);
3991
/* This is an error even in the 'check' case because the code just
3992
* consumed a non-IDAT header.
3994
if (png_ptr->chunk_name != png_IDAT)
3995
png_error(png_ptr, "Not enough image data");
3998
avail_in = png_ptr->IDAT_read_size;
4000
if (avail_in > png_ptr->idat_size)
4001
avail_in = (uInt)png_ptr->idat_size;
4003
/* A PNG with a gradually increasing IDAT size will defeat this attempt
4004
* to minimize memory usage by causing lots of re-allocs, but
4005
* realistically doing IDAT_read_size re-allocs is not likely to be a
4008
buffer = png_read_buffer(png_ptr, avail_in, 0/*error*/);
4010
png_crc_read(png_ptr, buffer, avail_in);
4011
png_ptr->idat_size -= avail_in;
4013
png_ptr->zstream.next_in = buffer;
4014
png_ptr->zstream.avail_in = avail_in;
4017
/* And set up the output side. */
4018
if (output != NULL) /* standard read */
4020
uInt out = ZLIB_IO_MAX;
4022
if (out > avail_out)
4023
out = (uInt)avail_out;
4026
png_ptr->zstream.avail_out = out;
4029
else /* after last row, checking for end */
4031
png_ptr->zstream.next_out = tmpbuf;
4032
png_ptr->zstream.avail_out = (sizeof tmpbuf);
4035
/* Use NO_FLUSH; this gives zlib the maximum opportunity to optimize the
4036
* process. If the LZ stream is truncated the sequential reader will
4037
* terminally damage the stream, above, by reading the chunk header of the
4038
* following chunk (it then exits with png_error).
4040
* TODO: deal more elegantly with truncated IDAT lists.
4042
ret = inflate(&png_ptr->zstream, Z_NO_FLUSH);
4044
/* Take the unconsumed output back. */
4046
avail_out += png_ptr->zstream.avail_out;
4048
else /* avail_out counts the extra bytes */
4049
avail_out += (sizeof tmpbuf) - png_ptr->zstream.avail_out;
4051
png_ptr->zstream.avail_out = 0;
4053
if (ret == Z_STREAM_END)
4055
/* Do this for safety; we won't read any more into this row. */
4056
png_ptr->zstream.next_out = NULL;
4058
png_ptr->mode |= PNG_AFTER_IDAT;
4059
png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
4061
if (png_ptr->zstream.avail_in > 0 || png_ptr->idat_size > 0)
4062
png_chunk_benign_error(png_ptr, "Extra compressed data");
4068
png_zstream_error(png_ptr, ret);
4071
png_chunk_error(png_ptr, png_ptr->zstream.msg);
4075
png_chunk_benign_error(png_ptr, png_ptr->zstream.msg);
4079
} while (avail_out > 0);
4083
/* The stream ended before the image; this is the same as too few IDATs so
4084
* should be handled the same way.
4087
png_error(png_ptr, "Not enough image data");
4089
else /* the deflate stream contained extra data */
4090
png_chunk_benign_error(png_ptr, "Too much image data");
4095
png_read_finish_IDAT(png_structrp png_ptr)
4097
/* We don't need any more data and the stream should have ended, however the
4098
* LZ end code may actually not have been processed. In this case we must
4099
* read it otherwise stray unread IDAT data or, more likely, an IDAT chunk
4100
* may still remain to be consumed.
4102
if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
4104
/* The NULL causes png_read_IDAT_data to swallow any remaining bytes in
4105
* the compressed stream, but the stream may be damaged too, so even after
4106
* this call we may need to terminate the zstream ownership.
4108
png_read_IDAT_data(png_ptr, NULL, 0);
4109
png_ptr->zstream.next_out = NULL; /* safety */
4111
/* Now clear everything out for safety; the following may not have been
4114
if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
4116
png_ptr->mode |= PNG_AFTER_IDAT;
4117
png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
4121
/* If the zstream has not been released do it now *and* terminate the reading
4122
* of the final IDAT chunk.
4124
if (png_ptr->zowner == png_IDAT)
4126
/* Always do this; the pointers otherwise point into the read buffer. */
4127
png_ptr->zstream.next_in = NULL;
4128
png_ptr->zstream.avail_in = 0;
4130
/* Now we no longer own the zstream. */
4131
png_ptr->zowner = 0;
4133
/* The slightly weird semantics of the sequential IDAT reading is that we
4134
* are always in or at the end of an IDAT chunk, so we always need to do a
4135
* crc_finish here. If idat_size is non-zero we also need to read the
4136
* spurious bytes at the end of the chunk now.
4138
(void)png_crc_finish(png_ptr, png_ptr->idat_size);
4143
png_read_finish_row(png_structrp png_ptr)
4145
/* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
4147
/* Start of interlace block */
4148
static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
4150
/* Offset to next interlace block */
4151
static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
4153
/* Start of interlace block in the y direction */
4154
static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
4156
/* Offset to next interlace block in the y direction */
4157
static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
4159
png_debug(1, "in png_read_finish_row");
4160
png_ptr->row_number++;
4161
if (png_ptr->row_number < png_ptr->num_rows)
4164
if (png_ptr->interlaced != 0)
4166
png_ptr->row_number = 0;
4168
/* TO DO: don't do this if prev_row isn't needed (requires
4169
* read-ahead of the next row's filter byte.
4171
memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
4177
if (png_ptr->pass >= 7)
4180
png_ptr->iwidth = (png_ptr->width +
4181
png_pass_inc[png_ptr->pass] - 1 -
4182
png_pass_start[png_ptr->pass]) /
4183
png_pass_inc[png_ptr->pass];
4185
if ((png_ptr->transformations & PNG_INTERLACE) == 0)
4187
png_ptr->num_rows = (png_ptr->height +
4188
png_pass_yinc[png_ptr->pass] - 1 -
4189
png_pass_ystart[png_ptr->pass]) /
4190
png_pass_yinc[png_ptr->pass];
4193
else /* if (png_ptr->transformations & PNG_INTERLACE) */
4194
break; /* libpng deinterlacing sees every row */
4196
} while (png_ptr->num_rows == 0 || png_ptr->iwidth == 0);
4198
if (png_ptr->pass < 7)
4202
/* Here after at the end of the last row of the last pass. */
4203
png_read_finish_IDAT(png_ptr);
4205
#endif /* SEQUENTIAL_READ */
4208
png_read_start_row(png_structrp png_ptr)
4210
/* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
4212
/* Start of interlace block */
4213
static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
4215
/* Offset to next interlace block */
4216
static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
4218
/* Start of interlace block in the y direction */
4219
static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
4221
/* Offset to next interlace block in the y direction */
4222
static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
4224
int max_pixel_depth;
4225
png_size_t row_bytes;
4227
png_debug(1, "in png_read_start_row");
4229
#ifdef PNG_READ_TRANSFORMS_SUPPORTED
4230
png_init_read_transformations(png_ptr);
4232
if (png_ptr->interlaced != 0)
4234
if ((png_ptr->transformations & PNG_INTERLACE) == 0)
4235
png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
4236
png_pass_ystart[0]) / png_pass_yinc[0];
4239
png_ptr->num_rows = png_ptr->height;
4241
png_ptr->iwidth = (png_ptr->width +
4242
png_pass_inc[png_ptr->pass] - 1 -
4243
png_pass_start[png_ptr->pass]) /
4244
png_pass_inc[png_ptr->pass];
4249
png_ptr->num_rows = png_ptr->height;
4250
png_ptr->iwidth = png_ptr->width;
4253
max_pixel_depth = png_ptr->pixel_depth;
4255
/* WARNING: * png_read_transform_info (pngrtran.c) performs a simpler set of
4256
* calculations to calculate the final pixel depth, then
4257
* png_do_read_transforms actually does the transforms. This means that the
4258
* code which effectively calculates this value is actually repeated in three
4259
* separate places. They must all match. Innocent changes to the order of
4260
* transformations can and will break libpng in a way that causes memory
4265
#ifdef PNG_READ_PACK_SUPPORTED
4266
if ((png_ptr->transformations & PNG_PACK) != 0 && png_ptr->bit_depth < 8)
4267
max_pixel_depth = 8;
4270
#ifdef PNG_READ_EXPAND_SUPPORTED
4271
if ((png_ptr->transformations & PNG_EXPAND) != 0)
4273
if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
4275
if (png_ptr->num_trans != 0)
4276
max_pixel_depth = 32;
4279
max_pixel_depth = 24;
4282
else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
4284
if (max_pixel_depth < 8)
4285
max_pixel_depth = 8;
4287
if (png_ptr->num_trans != 0)
4288
max_pixel_depth *= 2;
4291
else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
4293
if (png_ptr->num_trans != 0)
4295
max_pixel_depth *= 4;
4296
max_pixel_depth /= 3;
4302
#ifdef PNG_READ_EXPAND_16_SUPPORTED
4303
if ((png_ptr->transformations & PNG_EXPAND_16) != 0)
4305
# ifdef PNG_READ_EXPAND_SUPPORTED
4306
/* In fact it is an error if it isn't supported, but checking is
4309
if ((png_ptr->transformations & PNG_EXPAND) != 0)
4311
if (png_ptr->bit_depth < 16)
4312
max_pixel_depth *= 2;
4316
png_ptr->transformations &= ~PNG_EXPAND_16;
4320
#ifdef PNG_READ_FILLER_SUPPORTED
4321
if ((png_ptr->transformations & (PNG_FILLER)) != 0)
4323
if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
4325
if (max_pixel_depth <= 8)
4326
max_pixel_depth = 16;
4329
max_pixel_depth = 32;
4332
else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB ||
4333
png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
4335
if (max_pixel_depth <= 32)
4336
max_pixel_depth = 32;
4339
max_pixel_depth = 64;
4344
#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
4345
if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0)
4348
#ifdef PNG_READ_EXPAND_SUPPORTED
4349
(png_ptr->num_trans != 0 &&
4350
(png_ptr->transformations & PNG_EXPAND) != 0) ||
4352
#ifdef PNG_READ_FILLER_SUPPORTED
4353
(png_ptr->transformations & (PNG_FILLER)) != 0 ||
4355
png_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
4357
if (max_pixel_depth <= 16)
4358
max_pixel_depth = 32;
4361
max_pixel_depth = 64;
4366
if (max_pixel_depth <= 8)
4368
if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
4369
max_pixel_depth = 32;
4372
max_pixel_depth = 24;
4375
else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
4376
max_pixel_depth = 64;
4379
max_pixel_depth = 48;
4384
#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) && \
4385
defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
4386
if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
4388
int user_pixel_depth = png_ptr->user_transform_depth *
4389
png_ptr->user_transform_channels;
4391
if (user_pixel_depth > max_pixel_depth)
4392
max_pixel_depth = user_pixel_depth;
4396
/* This value is stored in png_struct and double checked in the row read
4399
png_ptr->maximum_pixel_depth = (png_byte)max_pixel_depth;
4400
png_ptr->transformed_pixel_depth = 0; /* calculated on demand */
4402
/* Align the width on the next larger 8 pixels. Mainly used
4405
row_bytes = ((png_ptr->width + 7) & ~((png_uint_32)7));
4406
/* Calculate the maximum bytes needed, adding a byte and a pixel
4409
row_bytes = PNG_ROWBYTES(max_pixel_depth, row_bytes) +
4410
1 + ((max_pixel_depth + 7) >> 3);
4412
#ifdef PNG_MAX_MALLOC_64K
4413
if (row_bytes > (png_uint_32)65536L)
4414
png_error(png_ptr, "This image requires a row greater than 64KB");
4417
if (row_bytes + 48 > png_ptr->old_big_row_buf_size)
4419
png_free(png_ptr, png_ptr->big_row_buf);
4420
png_free(png_ptr, png_ptr->big_prev_row);
4422
if (png_ptr->interlaced != 0)
4423
png_ptr->big_row_buf = (png_bytep)png_calloc(png_ptr,
4427
png_ptr->big_row_buf = (png_bytep)png_malloc(png_ptr, row_bytes + 48);
4429
png_ptr->big_prev_row = (png_bytep)png_malloc(png_ptr, row_bytes + 48);
4431
#ifdef PNG_ALIGNED_MEMORY_SUPPORTED
4432
/* Use 16-byte aligned memory for row_buf with at least 16 bytes
4433
* of padding before and after row_buf; treat prev_row similarly.
4434
* NOTE: the alignment is to the start of the pixels, one beyond the start
4435
* of the buffer, because of the filter byte. Prior to libpng 1.5.6 this
4436
* was incorrect; the filter byte was aligned, which had the exact
4437
* opposite effect of that intended.
4440
png_bytep temp = png_ptr->big_row_buf + 32;
4441
int extra = (int)((temp - (png_bytep)0) & 0x0f);
4442
png_ptr->row_buf = temp - extra - 1/*filter byte*/;
4444
temp = png_ptr->big_prev_row + 32;
4445
extra = (int)((temp - (png_bytep)0) & 0x0f);
4446
png_ptr->prev_row = temp - extra - 1/*filter byte*/;
4450
/* Use 31 bytes of padding before and 17 bytes after row_buf. */
4451
png_ptr->row_buf = png_ptr->big_row_buf + 31;
4452
png_ptr->prev_row = png_ptr->big_prev_row + 31;
4454
png_ptr->old_big_row_buf_size = row_bytes + 48;
4457
#ifdef PNG_MAX_MALLOC_64K
4458
if (png_ptr->rowbytes > 65535)
4459
png_error(png_ptr, "This image requires a row greater than 64KB");
4462
if (png_ptr->rowbytes > (PNG_SIZE_MAX - 1))
4463
png_error(png_ptr, "Row has too many bytes to allocate in memory");
4465
memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
4467
png_debug1(3, "width = %u,", png_ptr->width);
4468
png_debug1(3, "height = %u,", png_ptr->height);
4469
png_debug1(3, "iwidth = %u,", png_ptr->iwidth);
4470
png_debug1(3, "num_rows = %u,", png_ptr->num_rows);
4471
png_debug1(3, "rowbytes = %lu,", (unsigned long)png_ptr->rowbytes);
4472
png_debug1(3, "irowbytes = %lu",
4473
(unsigned long)PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->iwidth) + 1);
4475
/* The sequential reader needs a buffer for IDAT, but the progressive reader
4476
* does not, so free the read buffer now regardless; the sequential reader
4477
* reallocates it on demand.
4479
if (png_ptr->read_buffer != 0)
4481
png_bytep buffer = png_ptr->read_buffer;
4483
png_ptr->read_buffer_size = 0;
4484
png_ptr->read_buffer = NULL;
4485
png_free(png_ptr, buffer);
4488
/* Finally claim the zstream for the inflate of the IDAT data, use the bits
4489
* value from the stream (note that this will result in a fatal error if the
4490
* IDAT stream has a bogus deflate header window_bits value, but this should
4491
* not be happening any longer!)
4493
if (png_inflate_claim(png_ptr, png_IDAT) != Z_OK)
4494
png_error(png_ptr, png_ptr->zstream.msg);
4496
png_ptr->flags |= PNG_FLAG_ROW_INIT;