2 /* pngrutil.c - utilities to read a PNG file
4 * Last changed in libpng 1.6.18 [July 23, 2015]
5 * Copyright (c) 1998-2015 Glenn Randers-Pehrson
6 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
7 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
9 * This code is released under the libpng license.
10 * For conditions of distribution and use, see the disclaimer
11 * and license in png.h
13 * 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
22 png_get_uint_31(png_const_structrp png_ptr
, png_const_bytep buf
)
24 png_uint_32 uval
= png_get_uint_32(buf
);
26 if (uval
> PNG_UINT_31_MAX
)
27 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 */
41 png_get_fixed_point(png_structrp png_ptr
, png_const_bytep buf
)
43 png_uint_32 uval
= png_get_uint_32(buf
);
45 if (uval
<= PNG_UINT_31_MAX
)
46 return (png_fixed_point
)uval
; /* known to be in range */
48 /* The caller can turn off the warning by passing NULL. */
50 png_warning(png_ptr
, "PNG fixed point integer out of range");
52 return PNG_FIXED_ERROR
;
56 #ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
57 /* NOTE: the read macros will obscure these definitions, so that if
58 * 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
)
71 ((png_uint_32
)(*(buf
)) << 24) +
72 ((png_uint_32
)(*(buf
+ 1)) << 16) +
73 ((png_uint_32
)(*(buf
+ 2)) << 8) +
74 ((png_uint_32
)(*(buf
+ 3)) ) ;
79 /* Grab a signed 32-bit integer from a buffer in big-endian format. The
80 * 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
)
87 png_uint_32 uval
= png_get_uint_32(buf
);
88 if ((uval
& 0x80000000) == 0) /* non-negative */
91 uval
= (uval
^ 0xffffffff) + 1; /* 2's complement: -x = ~x+1 */
92 return -(png_int_32
)uval
;
95 /* Grab an unsigned 16-bit integer from a buffer in big-endian format. */
97 png_get_uint_16
)(png_const_bytep buf
)
99 /* ANSI-C requires an int value to accomodate at least 16 bits so this
100 * works and allows the compiler not to worry about possible narrowing
101 * on 32 bit systems. (Pre-ANSI systems did not make integers smaller
102 * than 16 bits either.)
105 ((unsigned int)(*buf
) << 8) +
106 ((unsigned int)(*(buf
+ 1)));
108 return (png_uint_16
)val
;
111 #endif /* READ_INT_FUNCTIONS */
113 /* Read and check the PNG file signature */
115 png_read_sig(png_structrp png_ptr
, png_inforp info_ptr
)
117 png_size_t num_checked
, num_to_check
;
119 /* Exit if the user application does not expect a signature. */
120 if (png_ptr
->sig_bytes
>= 8)
123 num_checked
= png_ptr
->sig_bytes
;
124 num_to_check
= 8 - num_checked
;
126 #ifdef PNG_IO_STATE_SUPPORTED
127 png_ptr
->io_state
= PNG_IO_READING
| PNG_IO_SIGNATURE
;
130 /* The signature must be serialized in a single I/O call. */
131 png_read_data(png_ptr
, &(info_ptr
->signature
[num_checked
]), num_to_check
);
132 png_ptr
->sig_bytes
= 8;
134 if (png_sig_cmp(info_ptr
->signature
, num_checked
, num_to_check
) != 0)
136 if (num_checked
< 4 &&
137 png_sig_cmp(info_ptr
->signature
, num_checked
, num_to_check
- 4))
138 png_error(png_ptr
, "Not a PNG file");
140 png_error(png_ptr
, "PNG file corrupted by ASCII conversion");
143 png_ptr
->mode
|= PNG_HAVE_PNG_SIGNATURE
;
146 /* Read the chunk header (length + type name).
147 * Put the type name into png_ptr->chunk_name, and return the length.
149 png_uint_32
/* PRIVATE */
150 png_read_chunk_header(png_structrp png_ptr
)
155 #ifdef PNG_IO_STATE_SUPPORTED
156 png_ptr
->io_state
= PNG_IO_READING
| PNG_IO_CHUNK_HDR
;
159 /* Read the length and the chunk name.
160 * This must be performed in a single I/O call.
162 png_read_data(png_ptr
, buf
, 8);
163 length
= png_get_uint_31(png_ptr
, buf
);
165 /* Put the chunk name into png_ptr->chunk_name. */
166 png_ptr
->chunk_name
= PNG_CHUNK_FROM_STRING(buf
+4);
168 png_debug2(0, "Reading %lx chunk, length = %lu",
169 (unsigned long)png_ptr
->chunk_name
, (unsigned long)length
);
171 /* Reset the crc and run it over the chunk name. */
172 png_reset_crc(png_ptr
);
173 png_calculate_crc(png_ptr
, buf
+ 4, 4);
175 /* Check to see if chunk name is valid. */
176 png_check_chunk_name(png_ptr
, png_ptr
->chunk_name
);
178 #ifdef PNG_IO_STATE_SUPPORTED
179 png_ptr
->io_state
= PNG_IO_READING
| PNG_IO_CHUNK_DATA
;
185 /* Read data, and (optionally) run it through the CRC. */
187 png_crc_read(png_structrp png_ptr
, png_bytep buf
, png_uint_32 length
)
192 png_read_data(png_ptr
, buf
, length
);
193 png_calculate_crc(png_ptr
, buf
, length
);
196 /* Optionally skip data and then check the CRC. Depending on whether we
197 * are reading an ancillary or critical chunk, and how the program has set
198 * things up, we may calculate the CRC on the data and print a message.
199 * Returns '1' if there was a CRC error, '0' otherwise.
202 png_crc_finish(png_structrp png_ptr
, png_uint_32 skip
)
204 /* The size of the local buffer for inflate is a good guess as to a
205 * reasonable size to use for buffering reads from the application.
210 png_byte tmpbuf
[PNG_INFLATE_BUF_SIZE
];
212 len
= (sizeof tmpbuf
);
217 png_crc_read(png_ptr
, tmpbuf
, len
);
220 if (png_crc_error(png_ptr
) != 0)
222 if (PNG_CHUNK_ANCILLARY(png_ptr
->chunk_name
) != 0 ?
223 (png_ptr
->flags
& PNG_FLAG_CRC_ANCILLARY_NOWARN
) == 0 :
224 (png_ptr
->flags
& PNG_FLAG_CRC_CRITICAL_USE
) != 0)
226 png_chunk_warning(png_ptr
, "CRC error");
230 png_chunk_error(png_ptr
, "CRC error");
238 /* Compare the CRC stored in the PNG file with that calculated by libpng from
239 * the data it has read thus far.
242 png_crc_error(png_structrp png_ptr
)
244 png_byte crc_bytes
[4];
248 if (PNG_CHUNK_ANCILLARY(png_ptr
->chunk_name
) != 0)
250 if ((png_ptr
->flags
& PNG_FLAG_CRC_ANCILLARY_MASK
) ==
251 (PNG_FLAG_CRC_ANCILLARY_USE
| PNG_FLAG_CRC_ANCILLARY_NOWARN
))
257 if ((png_ptr
->flags
& PNG_FLAG_CRC_CRITICAL_IGNORE
) != 0)
261 #ifdef PNG_IO_STATE_SUPPORTED
262 png_ptr
->io_state
= PNG_IO_READING
| PNG_IO_CHUNK_CRC
;
265 /* The chunk CRC must be serialized in a single I/O call. */
266 png_read_data(png_ptr
, crc_bytes
, 4);
270 crc
= png_get_uint_32(crc_bytes
);
271 return ((int)(crc
!= png_ptr
->crc
));
278 #if defined(PNG_READ_iCCP_SUPPORTED) || defined(PNG_READ_iTXt_SUPPORTED) ||\
279 defined(PNG_READ_pCAL_SUPPORTED) || defined(PNG_READ_sCAL_SUPPORTED) ||\
280 defined(PNG_READ_sPLT_SUPPORTED) || defined(PNG_READ_tEXt_SUPPORTED) ||\
281 defined(PNG_READ_zTXt_SUPPORTED) || defined(PNG_SEQUENTIAL_READ_SUPPORTED)
282 /* Manage the read buffer; this simply reallocates the buffer if it is not small
283 * enough (or if it is not allocated). The routine returns a pointer to the
284 * buffer; if an error occurs and 'warn' is set the routine returns NULL, else
285 * it will call png_error (via png_malloc) on failure. (warn == 2 means
289 png_read_buffer(png_structrp png_ptr
, png_alloc_size_t new_size
, int warn
)
291 png_bytep buffer
= png_ptr
->read_buffer
;
293 if (buffer
!= NULL
&& new_size
> png_ptr
->read_buffer_size
)
295 png_ptr
->read_buffer
= NULL
;
296 png_ptr
->read_buffer
= NULL
;
297 png_ptr
->read_buffer_size
= 0;
298 png_free(png_ptr
, buffer
);
304 buffer
= png_voidcast(png_bytep
, png_malloc_base(png_ptr
, new_size
));
308 png_ptr
->read_buffer
= buffer
;
309 png_ptr
->read_buffer_size
= new_size
;
312 else if (warn
< 2) /* else silent */
315 png_chunk_warning(png_ptr
, "insufficient memory to read chunk");
318 png_chunk_error(png_ptr
, "insufficient memory to read chunk");
324 #endif /* READ_iCCP|iTXt|pCAL|sCAL|sPLT|tEXt|zTXt|SEQUENTIAL_READ */
326 /* png_inflate_claim: claim the zstream for some nefarious purpose that involves
327 * decompression. Returns Z_OK on success, else a zlib error code. It checks
328 * the owner but, in final release builds, just issues a warning if some other
329 * chunk apparently owns the stream. Prior to release it does a png_error.
332 png_inflate_claim(png_structrp png_ptr
, png_uint_32 owner
)
334 if (png_ptr
->zowner
!= 0)
338 PNG_STRING_FROM_CHUNK(msg
, png_ptr
->zowner
);
339 /* So the message that results is "<chunk> using zstream"; this is an
340 * internal error, but is very useful for debugging. i18n requirements
343 (void)png_safecat(msg
, (sizeof msg
), 4, " using zstream");
344 #if PNG_RELEASE_BUILD
345 png_chunk_warning(png_ptr
, msg
);
348 png_chunk_error(png_ptr
, msg
);
352 /* Implementation note: unlike 'png_deflate_claim' this internal function
353 * does not take the size of the data as an argument. Some efficiency could
354 * be gained by using this when it is known *if* the zlib stream itself does
355 * not record the number; however, this is an illusion: the original writer
356 * of the PNG may have selected a lower window size, and we really must
357 * follow that because, for systems with with limited capabilities, we
358 * would otherwise reject the application's attempts to use a smaller window
359 * size (zlib doesn't have an interface to say "this or lower"!).
361 * inflateReset2 was added to zlib 1.2.4; before this the window could not be
362 * reset, therefore it is necessary to always allocate the maximum window
363 * size with earlier zlibs just in case later compressed chunks need it.
366 int ret
; /* zlib return code */
367 #if PNG_ZLIB_VERNUM >= 0x1240
369 # if defined(PNG_SET_OPTION_SUPPORTED) && defined(PNG_MAXIMUM_INFLATE_WINDOW)
372 if (((png_ptr
->options
>> PNG_MAXIMUM_INFLATE_WINDOW
) & 3) ==
379 # define window_bits 0
383 /* Set this for safety, just in case the previous owner left pointers to
384 * memory allocations.
386 png_ptr
->zstream
.next_in
= NULL
;
387 png_ptr
->zstream
.avail_in
= 0;
388 png_ptr
->zstream
.next_out
= NULL
;
389 png_ptr
->zstream
.avail_out
= 0;
391 if ((png_ptr
->flags
& PNG_FLAG_ZSTREAM_INITIALIZED
) != 0)
393 #if PNG_ZLIB_VERNUM < 0x1240
394 ret
= inflateReset(&png_ptr
->zstream
);
396 ret
= inflateReset2(&png_ptr
->zstream
, window_bits
);
402 #if PNG_ZLIB_VERNUM < 0x1240
403 ret
= inflateInit(&png_ptr
->zstream
);
405 ret
= inflateInit2(&png_ptr
->zstream
, window_bits
);
409 png_ptr
->flags
|= PNG_FLAG_ZSTREAM_INITIALIZED
;
413 png_ptr
->zowner
= owner
;
416 png_zstream_error(png_ptr
, ret
);
426 #ifdef PNG_READ_COMPRESSED_TEXT_SUPPORTED
427 /* png_inflate now returns zlib error codes including Z_OK and Z_STREAM_END to
428 * allow the caller to do multiple calls if required. If the 'finish' flag is
429 * set Z_FINISH will be passed to the final inflate() call and Z_STREAM_END must
430 * be returned or there has been a problem, otherwise Z_SYNC_FLUSH is used and
431 * Z_OK or Z_STREAM_END will be returned on success.
433 * The input and output sizes are updated to the actual amounts of data consumed
434 * or written, not the amount available (as in a z_stream). The data pointers
435 * are not changed, so the next input is (data+input_size) and the next
436 * available output is (output+output_size).
439 png_inflate(png_structrp png_ptr
, png_uint_32 owner
, int finish
,
440 /* INPUT: */ png_const_bytep input
, png_uint_32p input_size_ptr
,
441 /* OUTPUT: */ png_bytep output
, png_alloc_size_t
*output_size_ptr
)
443 if (png_ptr
->zowner
== owner
) /* Else not claimed */
446 png_alloc_size_t avail_out
= *output_size_ptr
;
447 png_uint_32 avail_in
= *input_size_ptr
;
449 /* zlib can't necessarily handle more than 65535 bytes at once (i.e. it
450 * can't even necessarily handle 65536 bytes) because the type uInt is
451 * "16 bits or more". Consequently it is necessary to chunk the input to
452 * zlib. This code uses ZLIB_IO_MAX, from pngpriv.h, as the maximum (the
453 * maximum value that can be stored in a uInt.) It is possible to set
454 * ZLIB_IO_MAX to a lower value in pngpriv.h and this may sometimes have
455 * a performance advantage, because it reduces the amount of data accessed
456 * at each step and that may give the OS more time to page it in.
458 png_ptr
->zstream
.next_in
= PNGZ_INPUT_CAST(input
);
459 /* avail_in and avail_out are set below from 'size' */
460 png_ptr
->zstream
.avail_in
= 0;
461 png_ptr
->zstream
.avail_out
= 0;
463 /* Read directly into the output if it is available (this is set to
464 * a local buffer below if output is NULL).
467 png_ptr
->zstream
.next_out
= output
;
472 Byte local_buffer
[PNG_INFLATE_BUF_SIZE
];
474 /* zlib INPUT BUFFER */
475 /* The setting of 'avail_in' used to be outside the loop; by setting it
476 * inside it is possible to chunk the input to zlib and simply rely on
477 * zlib to advance the 'next_in' pointer. This allows arbitrary
478 * amounts of data to be passed through zlib at the unavoidable cost of
479 * requiring a window save (memcpy of up to 32768 output bytes)
480 * every ZLIB_IO_MAX input bytes.
482 avail_in
+= png_ptr
->zstream
.avail_in
; /* not consumed last time */
486 if (avail_in
< avail
)
487 avail
= (uInt
)avail_in
; /* safe: < than ZLIB_IO_MAX */
490 png_ptr
->zstream
.avail_in
= avail
;
492 /* zlib OUTPUT BUFFER */
493 avail_out
+= png_ptr
->zstream
.avail_out
; /* not written last time */
495 avail
= ZLIB_IO_MAX
; /* maximum zlib can process */
499 /* Reset the output buffer each time round if output is NULL and
500 * make available the full buffer, up to 'remaining_space'
502 png_ptr
->zstream
.next_out
= local_buffer
;
503 if ((sizeof local_buffer
) < avail
)
504 avail
= (sizeof local_buffer
);
507 if (avail_out
< avail
)
508 avail
= (uInt
)avail_out
; /* safe: < ZLIB_IO_MAX */
510 png_ptr
->zstream
.avail_out
= avail
;
513 /* zlib inflate call */
514 /* In fact 'avail_out' may be 0 at this point, that happens at the end
515 * of the read when the final LZ end code was not passed at the end of
516 * the previous chunk of input data. Tell zlib if we have reached the
517 * end of the output buffer.
519 ret
= inflate(&png_ptr
->zstream
, avail_out
> 0 ? Z_NO_FLUSH
:
520 (finish
? Z_FINISH
: Z_SYNC_FLUSH
));
521 } while (ret
== Z_OK
);
523 /* For safety kill the local buffer pointer now */
525 png_ptr
->zstream
.next_out
= NULL
;
527 /* Claw back the 'size' and 'remaining_space' byte counts. */
528 avail_in
+= png_ptr
->zstream
.avail_in
;
529 avail_out
+= png_ptr
->zstream
.avail_out
;
531 /* Update the input and output sizes; the updated values are the amount
532 * consumed or written, effectively the inverse of what zlib uses.
535 *output_size_ptr
-= avail_out
;
538 *input_size_ptr
-= avail_in
;
540 /* Ensure png_ptr->zstream.msg is set (even in the success case!) */
541 png_zstream_error(png_ptr
, ret
);
547 /* This is a bad internal error. The recovery assigns to the zstream msg
548 * pointer, which is not owned by the caller, but this is safe; it's only
551 png_ptr
->zstream
.msg
= PNGZ_MSG_CAST("zstream unclaimed");
552 return Z_STREAM_ERROR
;
557 * Decompress trailing data in a chunk. The assumption is that read_buffer
558 * points at an allocated area holding the contents of a chunk with a
559 * trailing compressed part. What we get back is an allocated area
560 * holding the original prefix part and an uncompressed version of the
561 * trailing part (the malloc area passed in is freed).
564 png_decompress_chunk(png_structrp png_ptr
,
565 png_uint_32 chunklength
, png_uint_32 prefix_size
,
566 png_alloc_size_t
*newlength
/* must be initialized to the maximum! */,
567 int terminate
/*add a '\0' to the end of the uncompressed data*/)
569 /* TODO: implement different limits for different types of chunk.
571 * The caller supplies *newlength set to the maximum length of the
572 * uncompressed data, but this routine allocates space for the prefix and
573 * maybe a '\0' terminator too. We have to assume that 'prefix_size' is
574 * limited only by the maximum chunk size.
576 png_alloc_size_t limit
= PNG_SIZE_MAX
;
578 # ifdef PNG_SET_USER_LIMITS_SUPPORTED
579 if (png_ptr
->user_chunk_malloc_max
> 0 &&
580 png_ptr
->user_chunk_malloc_max
< limit
)
581 limit
= png_ptr
->user_chunk_malloc_max
;
582 # elif PNG_USER_CHUNK_MALLOC_MAX > 0
583 if (PNG_USER_CHUNK_MALLOC_MAX
< limit
)
584 limit
= PNG_USER_CHUNK_MALLOC_MAX
;
587 if (limit
>= prefix_size
+ (terminate
!= 0))
591 limit
-= prefix_size
+ (terminate
!= 0);
593 if (limit
< *newlength
)
596 /* Now try to claim the stream. */
597 ret
= png_inflate_claim(png_ptr
, png_ptr
->chunk_name
);
601 png_uint_32 lzsize
= chunklength
- prefix_size
;
603 ret
= png_inflate(png_ptr
, png_ptr
->chunk_name
, 1/*finish*/,
604 /* input: */ png_ptr
->read_buffer
+ prefix_size
, &lzsize
,
605 /* output: */ NULL
, newlength
);
607 if (ret
== Z_STREAM_END
)
609 /* Use 'inflateReset' here, not 'inflateReset2' because this
610 * preserves the previously decided window size (otherwise it would
611 * be necessary to store the previous window size.) In practice
612 * this doesn't matter anyway, because png_inflate will call inflate
613 * with Z_FINISH in almost all cases, so the window will not be
616 if (inflateReset(&png_ptr
->zstream
) == Z_OK
)
618 /* Because of the limit checks above we know that the new,
619 * expanded, size will fit in a size_t (let alone an
620 * png_alloc_size_t). Use png_malloc_base here to avoid an
623 png_alloc_size_t new_size
= *newlength
;
624 png_alloc_size_t buffer_size
= prefix_size
+ new_size
+
626 png_bytep text
= png_voidcast(png_bytep
, png_malloc_base(png_ptr
,
631 ret
= png_inflate(png_ptr
, png_ptr
->chunk_name
, 1/*finish*/,
632 png_ptr
->read_buffer
+ prefix_size
, &lzsize
,
633 text
+ prefix_size
, newlength
);
635 if (ret
== Z_STREAM_END
)
637 if (new_size
== *newlength
)
640 text
[prefix_size
+ *newlength
] = 0;
643 memcpy(text
, png_ptr
->read_buffer
, prefix_size
);
646 png_bytep old_ptr
= png_ptr
->read_buffer
;
648 png_ptr
->read_buffer
= text
;
649 png_ptr
->read_buffer_size
= buffer_size
;
650 text
= old_ptr
; /* freed below */
656 /* The size changed on the second read, there can be no
657 * guarantee that anything is correct at this point.
658 * The 'msg' pointer has been set to "unexpected end of
659 * LZ stream", which is fine, but return an error code
660 * that the caller won't accept.
662 ret
= PNG_UNEXPECTED_ZLIB_RETURN
;
666 else if (ret
== Z_OK
)
667 ret
= PNG_UNEXPECTED_ZLIB_RETURN
; /* for safety */
669 /* Free the text pointer (this is the old read_buffer on
672 png_free(png_ptr
, text
);
674 /* This really is very benign, but it's still an error because
675 * the extra space may otherwise be used as a Trojan Horse.
677 if (ret
== Z_STREAM_END
&&
678 chunklength
- prefix_size
!= lzsize
)
679 png_chunk_benign_error(png_ptr
, "extra compressed data");
684 /* Out of memory allocating the buffer */
686 png_zstream_error(png_ptr
, Z_MEM_ERROR
);
692 /* inflateReset failed, store the error message */
693 png_zstream_error(png_ptr
, ret
);
695 if (ret
== Z_STREAM_END
)
696 ret
= PNG_UNEXPECTED_ZLIB_RETURN
;
700 else if (ret
== Z_OK
)
701 ret
= PNG_UNEXPECTED_ZLIB_RETURN
;
703 /* Release the claimed stream */
707 else /* the claim failed */ if (ret
== Z_STREAM_END
) /* impossible! */
708 ret
= PNG_UNEXPECTED_ZLIB_RETURN
;
715 /* Application/configuration limits exceeded */
716 png_zstream_error(png_ptr
, Z_MEM_ERROR
);
720 #endif /* READ_COMPRESSED_TEXT */
722 #ifdef PNG_READ_iCCP_SUPPORTED
723 /* Perform a partial read and decompress, producing 'avail_out' bytes and
724 * reading from the current chunk as required.
727 png_inflate_read(png_structrp png_ptr
, png_bytep read_buffer
, uInt read_size
,
728 png_uint_32p chunk_bytes
, png_bytep next_out
, png_alloc_size_t
*out_size
,
731 if (png_ptr
->zowner
== png_ptr
->chunk_name
)
735 /* next_in and avail_in must have been initialized by the caller. */
736 png_ptr
->zstream
.next_out
= next_out
;
737 png_ptr
->zstream
.avail_out
= 0; /* set in the loop */
741 if (png_ptr
->zstream
.avail_in
== 0)
743 if (read_size
> *chunk_bytes
)
744 read_size
= (uInt
)*chunk_bytes
;
745 *chunk_bytes
-= read_size
;
748 png_crc_read(png_ptr
, read_buffer
, read_size
);
750 png_ptr
->zstream
.next_in
= read_buffer
;
751 png_ptr
->zstream
.avail_in
= read_size
;
754 if (png_ptr
->zstream
.avail_out
== 0)
756 uInt avail
= ZLIB_IO_MAX
;
757 if (avail
> *out_size
)
758 avail
= (uInt
)*out_size
;
761 png_ptr
->zstream
.avail_out
= avail
;
764 /* Use Z_SYNC_FLUSH when there is no more chunk data to ensure that all
765 * the available output is produced; this allows reading of truncated
768 ret
= inflate(&png_ptr
->zstream
,
769 *chunk_bytes
> 0 ? Z_NO_FLUSH
: (finish
? Z_FINISH
: Z_SYNC_FLUSH
));
771 while (ret
== Z_OK
&& (*out_size
> 0 || png_ptr
->zstream
.avail_out
> 0));
773 *out_size
+= png_ptr
->zstream
.avail_out
;
774 png_ptr
->zstream
.avail_out
= 0; /* Should not be required, but is safe */
776 /* Ensure the error message pointer is always set: */
777 png_zstream_error(png_ptr
, ret
);
783 png_ptr
->zstream
.msg
= PNGZ_MSG_CAST("zstream unclaimed");
784 return Z_STREAM_ERROR
;
789 /* Read and check the IDHR chunk */
792 png_handle_IHDR(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
795 png_uint_32 width
, height
;
796 int bit_depth
, color_type
, compression_type
, filter_type
;
799 png_debug(1, "in png_handle_IHDR");
801 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) != 0)
802 png_chunk_error(png_ptr
, "out of place");
804 /* Check the length */
806 png_chunk_error(png_ptr
, "invalid");
808 png_ptr
->mode
|= PNG_HAVE_IHDR
;
810 png_crc_read(png_ptr
, buf
, 13);
811 png_crc_finish(png_ptr
, 0);
813 width
= png_get_uint_31(png_ptr
, buf
);
814 height
= png_get_uint_31(png_ptr
, buf
+ 4);
817 compression_type
= buf
[10];
818 filter_type
= buf
[11];
819 interlace_type
= buf
[12];
821 /* Set internal variables */
822 png_ptr
->width
= width
;
823 png_ptr
->height
= height
;
824 png_ptr
->bit_depth
= (png_byte
)bit_depth
;
825 png_ptr
->interlaced
= (png_byte
)interlace_type
;
826 png_ptr
->color_type
= (png_byte
)color_type
;
827 #ifdef PNG_MNG_FEATURES_SUPPORTED
828 png_ptr
->filter_type
= (png_byte
)filter_type
;
830 png_ptr
->compression_type
= (png_byte
)compression_type
;
832 /* Find number of channels */
833 switch (png_ptr
->color_type
)
835 default: /* invalid, png_set_IHDR calls png_error */
836 case PNG_COLOR_TYPE_GRAY
:
837 case PNG_COLOR_TYPE_PALETTE
:
838 png_ptr
->channels
= 1;
841 case PNG_COLOR_TYPE_RGB
:
842 png_ptr
->channels
= 3;
845 case PNG_COLOR_TYPE_GRAY_ALPHA
:
846 png_ptr
->channels
= 2;
849 case PNG_COLOR_TYPE_RGB_ALPHA
:
850 png_ptr
->channels
= 4;
854 /* Set up other useful info */
855 png_ptr
->pixel_depth
= (png_byte
)(png_ptr
->bit_depth
* png_ptr
->channels
);
856 png_ptr
->rowbytes
= PNG_ROWBYTES(png_ptr
->pixel_depth
, png_ptr
->width
);
857 png_debug1(3, "bit_depth = %d", png_ptr
->bit_depth
);
858 png_debug1(3, "channels = %d", png_ptr
->channels
);
859 png_debug1(3, "rowbytes = %lu", (unsigned long)png_ptr
->rowbytes
);
860 png_set_IHDR(png_ptr
, info_ptr
, width
, height
, bit_depth
,
861 color_type
, interlace_type
, compression_type
, filter_type
);
864 /* Read and check the palette */
866 png_handle_PLTE(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
868 png_color palette
[PNG_MAX_PALETTE_LENGTH
];
870 #ifdef PNG_POINTER_INDEXING_SUPPORTED
874 png_debug(1, "in png_handle_PLTE");
876 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
877 png_chunk_error(png_ptr
, "missing IHDR");
879 /* Moved to before the 'after IDAT' check below because otherwise duplicate
880 * PLTE chunks are potentially ignored (the spec says there shall not be more
881 * than one PLTE, the error is not treated as benign, so this check trumps
882 * the requirement that PLTE appears before IDAT.)
884 else if ((png_ptr
->mode
& PNG_HAVE_PLTE
) != 0)
885 png_chunk_error(png_ptr
, "duplicate");
887 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
889 /* This is benign because the non-benign error happened before, when an
890 * IDAT was encountered in a color-mapped image with no PLTE.
892 png_crc_finish(png_ptr
, length
);
893 png_chunk_benign_error(png_ptr
, "out of place");
897 png_ptr
->mode
|= PNG_HAVE_PLTE
;
899 if ((png_ptr
->color_type
& PNG_COLOR_MASK_COLOR
) == 0)
901 png_crc_finish(png_ptr
, length
);
902 png_chunk_benign_error(png_ptr
, "ignored in grayscale PNG");
906 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
907 if (png_ptr
->color_type
!= PNG_COLOR_TYPE_PALETTE
)
909 png_crc_finish(png_ptr
, length
);
914 if (length
> 3*PNG_MAX_PALETTE_LENGTH
|| length
% 3)
916 png_crc_finish(png_ptr
, length
);
918 if (png_ptr
->color_type
!= PNG_COLOR_TYPE_PALETTE
)
919 png_chunk_benign_error(png_ptr
, "invalid");
922 png_chunk_error(png_ptr
, "invalid");
927 /* The cast is safe because 'length' is less than 3*PNG_MAX_PALETTE_LENGTH */
928 num
= (int)length
/ 3;
930 #ifdef PNG_POINTER_INDEXING_SUPPORTED
931 for (i
= 0, pal_ptr
= palette
; i
< num
; i
++, pal_ptr
++)
935 png_crc_read(png_ptr
, buf
, 3);
936 pal_ptr
->red
= buf
[0];
937 pal_ptr
->green
= buf
[1];
938 pal_ptr
->blue
= buf
[2];
941 for (i
= 0; i
< num
; i
++)
945 png_crc_read(png_ptr
, buf
, 3);
946 /* Don't depend upon png_color being any order */
947 palette
[i
].red
= buf
[0];
948 palette
[i
].green
= buf
[1];
949 palette
[i
].blue
= buf
[2];
953 /* If we actually need the PLTE chunk (ie for a paletted image), we do
954 * whatever the normal CRC configuration tells us. However, if we
955 * have an RGB image, the PLTE can be considered ancillary, so
956 * we will act as though it is.
958 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
959 if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
962 png_crc_finish(png_ptr
, 0);
965 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
966 else if (png_crc_error(png_ptr
) != 0) /* Only if we have a CRC error */
968 /* If we don't want to use the data from an ancillary chunk,
969 * we have two options: an error abort, or a warning and we
970 * ignore the data in this chunk (which should be OK, since
971 * it's considered ancillary for a RGB or RGBA image).
973 * IMPLEMENTATION NOTE: this is only here because png_crc_finish uses the
974 * chunk type to determine whether to check the ancillary or the critical
977 if ((png_ptr
->flags
& PNG_FLAG_CRC_ANCILLARY_USE
) == 0)
979 if ((png_ptr
->flags
& PNG_FLAG_CRC_ANCILLARY_NOWARN
) != 0)
983 png_chunk_error(png_ptr
, "CRC error");
986 /* Otherwise, we (optionally) emit a warning and use the chunk. */
987 else if ((png_ptr
->flags
& PNG_FLAG_CRC_ANCILLARY_NOWARN
) == 0)
988 png_chunk_warning(png_ptr
, "CRC error");
992 /* TODO: png_set_PLTE has the side effect of setting png_ptr->palette to its
993 * own copy of the palette. This has the side effect that when png_start_row
994 * is called (this happens after any call to png_read_update_info) the
995 * info_ptr palette gets changed. This is extremely unexpected and
998 * Fix this by not sharing the palette in this way.
1000 png_set_PLTE(png_ptr
, info_ptr
, palette
, num
);
1002 /* The three chunks, bKGD, hIST and tRNS *must* appear after PLTE and before
1003 * IDAT. Prior to 1.6.0 this was not checked; instead the code merely
1004 * checked the apparent validity of a tRNS chunk inserted before PLTE on a
1005 * palette PNG. 1.6.0 attempts to rigorously follow the standard and
1006 * therefore does a benign error if the erroneous condition is detected *and*
1007 * cancels the tRNS if the benign error returns. The alternative is to
1008 * amend the standard since it would be rather hypocritical of the standards
1009 * maintainers to ignore it.
1011 #ifdef PNG_READ_tRNS_SUPPORTED
1012 if (png_ptr
->num_trans
> 0 ||
1013 (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_tRNS
) != 0))
1015 /* Cancel this because otherwise it would be used if the transforms
1016 * require it. Don't cancel the 'valid' flag because this would prevent
1017 * detection of duplicate chunks.
1019 png_ptr
->num_trans
= 0;
1021 if (info_ptr
!= NULL
)
1022 info_ptr
->num_trans
= 0;
1024 png_chunk_benign_error(png_ptr
, "tRNS must be after");
1028 #ifdef PNG_READ_hIST_SUPPORTED
1029 if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_hIST
) != 0)
1030 png_chunk_benign_error(png_ptr
, "hIST must be after");
1033 #ifdef PNG_READ_bKGD_SUPPORTED
1034 if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_bKGD
) != 0)
1035 png_chunk_benign_error(png_ptr
, "bKGD must be after");
1040 png_handle_IEND(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1042 png_debug(1, "in png_handle_IEND");
1044 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0 ||
1045 (png_ptr
->mode
& PNG_HAVE_IDAT
) == 0)
1046 png_chunk_error(png_ptr
, "out of place");
1048 png_ptr
->mode
|= (PNG_AFTER_IDAT
| PNG_HAVE_IEND
);
1050 png_crc_finish(png_ptr
, length
);
1053 png_chunk_benign_error(png_ptr
, "invalid");
1055 PNG_UNUSED(info_ptr
)
1058 #ifdef PNG_READ_gAMA_SUPPORTED
1060 png_handle_gAMA(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1062 png_fixed_point igamma
;
1065 png_debug(1, "in png_handle_gAMA");
1067 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1068 png_chunk_error(png_ptr
, "missing IHDR");
1070 else if ((png_ptr
->mode
& (PNG_HAVE_IDAT
|PNG_HAVE_PLTE
)) != 0)
1072 png_crc_finish(png_ptr
, length
);
1073 png_chunk_benign_error(png_ptr
, "out of place");
1079 png_crc_finish(png_ptr
, length
);
1080 png_chunk_benign_error(png_ptr
, "invalid");
1084 png_crc_read(png_ptr
, buf
, 4);
1086 if (png_crc_finish(png_ptr
, 0) != 0)
1089 igamma
= png_get_fixed_point(NULL
, buf
);
1091 png_colorspace_set_gamma(png_ptr
, &png_ptr
->colorspace
, igamma
);
1092 png_colorspace_sync(png_ptr
, info_ptr
);
1096 #ifdef PNG_READ_sBIT_SUPPORTED
1098 png_handle_sBIT(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1100 unsigned int truelen
, i
;
1101 png_byte sample_depth
;
1104 png_debug(1, "in png_handle_sBIT");
1106 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1107 png_chunk_error(png_ptr
, "missing IHDR");
1109 else if ((png_ptr
->mode
& (PNG_HAVE_IDAT
|PNG_HAVE_PLTE
)) != 0)
1111 png_crc_finish(png_ptr
, length
);
1112 png_chunk_benign_error(png_ptr
, "out of place");
1116 if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_sBIT
) != 0)
1118 png_crc_finish(png_ptr
, length
);
1119 png_chunk_benign_error(png_ptr
, "duplicate");
1123 if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
1131 truelen
= png_ptr
->channels
;
1132 sample_depth
= png_ptr
->bit_depth
;
1135 if (length
!= truelen
|| length
> 4)
1137 png_chunk_benign_error(png_ptr
, "invalid");
1138 png_crc_finish(png_ptr
, length
);
1142 buf
[0] = buf
[1] = buf
[2] = buf
[3] = sample_depth
;
1143 png_crc_read(png_ptr
, buf
, truelen
);
1145 if (png_crc_finish(png_ptr
, 0) != 0)
1148 for (i
=0; i
<truelen
; ++i
)
1150 if (buf
[i
] == 0 || buf
[i
] > sample_depth
)
1152 png_chunk_benign_error(png_ptr
, "invalid");
1157 if ((png_ptr
->color_type
& PNG_COLOR_MASK_COLOR
) != 0)
1159 png_ptr
->sig_bit
.red
= buf
[0];
1160 png_ptr
->sig_bit
.green
= buf
[1];
1161 png_ptr
->sig_bit
.blue
= buf
[2];
1162 png_ptr
->sig_bit
.alpha
= buf
[3];
1167 png_ptr
->sig_bit
.gray
= buf
[0];
1168 png_ptr
->sig_bit
.red
= buf
[0];
1169 png_ptr
->sig_bit
.green
= buf
[0];
1170 png_ptr
->sig_bit
.blue
= buf
[0];
1171 png_ptr
->sig_bit
.alpha
= buf
[1];
1174 png_set_sBIT(png_ptr
, info_ptr
, &(png_ptr
->sig_bit
));
1178 #ifdef PNG_READ_cHRM_SUPPORTED
1180 png_handle_cHRM(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1185 png_debug(1, "in png_handle_cHRM");
1187 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1188 png_chunk_error(png_ptr
, "missing IHDR");
1190 else if ((png_ptr
->mode
& (PNG_HAVE_IDAT
|PNG_HAVE_PLTE
)) != 0)
1192 png_crc_finish(png_ptr
, length
);
1193 png_chunk_benign_error(png_ptr
, "out of place");
1199 png_crc_finish(png_ptr
, length
);
1200 png_chunk_benign_error(png_ptr
, "invalid");
1204 png_crc_read(png_ptr
, buf
, 32);
1206 if (png_crc_finish(png_ptr
, 0) != 0)
1209 xy
.whitex
= png_get_fixed_point(NULL
, buf
);
1210 xy
.whitey
= png_get_fixed_point(NULL
, buf
+ 4);
1211 xy
.redx
= png_get_fixed_point(NULL
, buf
+ 8);
1212 xy
.redy
= png_get_fixed_point(NULL
, buf
+ 12);
1213 xy
.greenx
= png_get_fixed_point(NULL
, buf
+ 16);
1214 xy
.greeny
= png_get_fixed_point(NULL
, buf
+ 20);
1215 xy
.bluex
= png_get_fixed_point(NULL
, buf
+ 24);
1216 xy
.bluey
= png_get_fixed_point(NULL
, buf
+ 28);
1218 if (xy
.whitex
== PNG_FIXED_ERROR
||
1219 xy
.whitey
== PNG_FIXED_ERROR
||
1220 xy
.redx
== PNG_FIXED_ERROR
||
1221 xy
.redy
== PNG_FIXED_ERROR
||
1222 xy
.greenx
== PNG_FIXED_ERROR
||
1223 xy
.greeny
== PNG_FIXED_ERROR
||
1224 xy
.bluex
== PNG_FIXED_ERROR
||
1225 xy
.bluey
== PNG_FIXED_ERROR
)
1227 png_chunk_benign_error(png_ptr
, "invalid values");
1231 /* If a colorspace error has already been output skip this chunk */
1232 if ((png_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
) != 0)
1235 if ((png_ptr
->colorspace
.flags
& PNG_COLORSPACE_FROM_cHRM
) != 0)
1237 png_ptr
->colorspace
.flags
|= PNG_COLORSPACE_INVALID
;
1238 png_colorspace_sync(png_ptr
, info_ptr
);
1239 png_chunk_benign_error(png_ptr
, "duplicate");
1243 png_ptr
->colorspace
.flags
|= PNG_COLORSPACE_FROM_cHRM
;
1244 (void)png_colorspace_set_chromaticities(png_ptr
, &png_ptr
->colorspace
, &xy
,
1245 1/*prefer cHRM values*/);
1246 png_colorspace_sync(png_ptr
, info_ptr
);
1250 #ifdef PNG_READ_sRGB_SUPPORTED
1252 png_handle_sRGB(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1256 png_debug(1, "in png_handle_sRGB");
1258 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1259 png_chunk_error(png_ptr
, "missing IHDR");
1261 else if ((png_ptr
->mode
& (PNG_HAVE_IDAT
|PNG_HAVE_PLTE
)) != 0)
1263 png_crc_finish(png_ptr
, length
);
1264 png_chunk_benign_error(png_ptr
, "out of place");
1270 png_crc_finish(png_ptr
, length
);
1271 png_chunk_benign_error(png_ptr
, "invalid");
1275 png_crc_read(png_ptr
, &intent
, 1);
1277 if (png_crc_finish(png_ptr
, 0) != 0)
1280 /* If a colorspace error has already been output skip this chunk */
1281 if ((png_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
) != 0)
1284 /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
1287 if ((png_ptr
->colorspace
.flags
& PNG_COLORSPACE_HAVE_INTENT
) != 0)
1289 png_ptr
->colorspace
.flags
|= PNG_COLORSPACE_INVALID
;
1290 png_colorspace_sync(png_ptr
, info_ptr
);
1291 png_chunk_benign_error(png_ptr
, "too many profiles");
1295 (void)png_colorspace_set_sRGB(png_ptr
, &png_ptr
->colorspace
, intent
);
1296 png_colorspace_sync(png_ptr
, info_ptr
);
1298 #endif /* READ_sRGB */
1300 #ifdef PNG_READ_iCCP_SUPPORTED
1302 png_handle_iCCP(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1303 /* Note: this does not properly handle profiles that are > 64K under DOS */
1305 png_const_charp errmsg
= NULL
; /* error message output, or no error */
1306 int finished
= 0; /* crc checked */
1308 png_debug(1, "in png_handle_iCCP");
1310 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1311 png_chunk_error(png_ptr
, "missing IHDR");
1313 else if ((png_ptr
->mode
& (PNG_HAVE_IDAT
|PNG_HAVE_PLTE
)) != 0)
1315 png_crc_finish(png_ptr
, length
);
1316 png_chunk_benign_error(png_ptr
, "out of place");
1320 /* Consistent with all the above colorspace handling an obviously *invalid*
1321 * chunk is just ignored, so does not invalidate the color space. An
1322 * alternative is to set the 'invalid' flags at the start of this routine
1323 * and only clear them in they were not set before and all the tests pass.
1324 * The minimum 'deflate' stream is assumed to be just the 2 byte header and
1325 * 4 byte checksum. The keyword must be at least one character and there is
1326 * a terminator (0) byte and the compression method.
1330 png_crc_finish(png_ptr
, length
);
1331 png_chunk_benign_error(png_ptr
, "too short");
1335 /* If a colorspace error has already been output skip this chunk */
1336 if ((png_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
) != 0)
1338 png_crc_finish(png_ptr
, length
);
1342 /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
1345 if ((png_ptr
->colorspace
.flags
& PNG_COLORSPACE_HAVE_INTENT
) == 0)
1347 uInt read_length
, keyword_length
;
1350 /* Find the keyword; the keyword plus separator and compression method
1351 * bytes can be at most 81 characters long.
1353 read_length
= 81; /* maximum */
1354 if (read_length
> length
)
1355 read_length
= (uInt
)length
;
1357 png_crc_read(png_ptr
, (png_bytep
)keyword
, read_length
);
1358 length
-= read_length
;
1361 while (keyword_length
< 80 && keyword_length
< read_length
&&
1362 keyword
[keyword_length
] != 0)
1365 /* TODO: make the keyword checking common */
1366 if (keyword_length
>= 1 && keyword_length
<= 79)
1368 /* We only understand '0' compression - deflate - so if we get a
1369 * different value we can't safely decode the chunk.
1371 if (keyword_length
+1 < read_length
&&
1372 keyword
[keyword_length
+1] == PNG_COMPRESSION_TYPE_BASE
)
1374 read_length
-= keyword_length
+2;
1376 if (png_inflate_claim(png_ptr
, png_iCCP
) == Z_OK
)
1378 Byte profile_header
[132];
1379 Byte local_buffer
[PNG_INFLATE_BUF_SIZE
];
1380 png_alloc_size_t size
= (sizeof profile_header
);
1382 png_ptr
->zstream
.next_in
= (Bytef
*)keyword
+ (keyword_length
+2);
1383 png_ptr
->zstream
.avail_in
= read_length
;
1384 (void)png_inflate_read(png_ptr
, local_buffer
,
1385 (sizeof local_buffer
), &length
, profile_header
, &size
,
1386 0/*finish: don't, because the output is too small*/);
1390 /* We have the ICC profile header; do the basic header checks.
1392 const png_uint_32 profile_length
=
1393 png_get_uint_32(profile_header
);
1395 if (png_icc_check_length(png_ptr
, &png_ptr
->colorspace
,
1396 keyword
, profile_length
) != 0)
1398 /* The length is apparently ok, so we can check the 132
1401 if (png_icc_check_header(png_ptr
, &png_ptr
->colorspace
,
1402 keyword
, profile_length
, profile_header
,
1403 png_ptr
->color_type
) != 0)
1405 /* Now read the tag table; a variable size buffer is
1406 * needed at this point, allocate one for the whole
1407 * profile. The header check has already validated
1408 * that none of these stuff will overflow.
1410 const png_uint_32 tag_count
= png_get_uint_32(
1411 profile_header
+128);
1412 png_bytep profile
= png_read_buffer(png_ptr
,
1413 profile_length
, 2/*silent*/);
1415 if (profile
!= NULL
)
1417 memcpy(profile
, profile_header
,
1418 (sizeof profile_header
));
1420 size
= 12 * tag_count
;
1422 (void)png_inflate_read(png_ptr
, local_buffer
,
1423 (sizeof local_buffer
), &length
,
1424 profile
+ (sizeof profile_header
), &size
, 0);
1426 /* Still expect a buffer error because we expect
1427 * there to be some tag data!
1431 if (png_icc_check_tag_table(png_ptr
,
1432 &png_ptr
->colorspace
, keyword
, profile_length
,
1435 /* The profile has been validated for basic
1436 * security issues, so read the whole thing in.
1438 size
= profile_length
- (sizeof profile_header
)
1441 (void)png_inflate_read(png_ptr
, local_buffer
,
1442 (sizeof local_buffer
), &length
,
1443 profile
+ (sizeof profile_header
) +
1444 12 * tag_count
, &size
, 1/*finish*/);
1446 if (length
> 0 && !(png_ptr
->flags
&
1447 PNG_FLAG_BENIGN_ERRORS_WARN
))
1448 errmsg
= "extra compressed data";
1450 /* But otherwise allow extra data: */
1455 /* This can be handled completely, so
1458 png_chunk_warning(png_ptr
,
1459 "extra compressed data");
1462 png_crc_finish(png_ptr
, length
);
1465 # ifdef PNG_sRGB_SUPPORTED
1466 /* Check for a match against sRGB */
1467 png_icc_set_sRGB(png_ptr
,
1468 &png_ptr
->colorspace
, profile
,
1469 png_ptr
->zstream
.adler
);
1472 /* Steal the profile for info_ptr. */
1473 if (info_ptr
!= NULL
)
1475 png_free_data(png_ptr
, info_ptr
,
1478 info_ptr
->iccp_name
= png_voidcast(char*,
1479 png_malloc_base(png_ptr
,
1481 if (info_ptr
->iccp_name
!= NULL
)
1483 memcpy(info_ptr
->iccp_name
, keyword
,
1485 info_ptr
->iccp_proflen
=
1487 info_ptr
->iccp_profile
= profile
;
1488 png_ptr
->read_buffer
= NULL
; /*steal*/
1489 info_ptr
->free_me
|= PNG_FREE_ICCP
;
1490 info_ptr
->valid
|= PNG_INFO_iCCP
;
1495 png_ptr
->colorspace
.flags
|=
1496 PNG_COLORSPACE_INVALID
;
1497 errmsg
= "out of memory";
1501 /* else the profile remains in the read
1502 * buffer which gets reused for subsequent
1506 if (info_ptr
!= NULL
)
1507 png_colorspace_sync(png_ptr
, info_ptr
);
1511 png_ptr
->zowner
= 0;
1517 errmsg
= "truncated";
1519 #ifndef __COVERITY__
1521 errmsg
= png_ptr
->zstream
.msg
;
1525 /* else png_icc_check_tag_table output an error */
1528 else /* profile truncated */
1529 errmsg
= png_ptr
->zstream
.msg
;
1533 errmsg
= "out of memory";
1536 /* else png_icc_check_header output an error */
1539 /* else png_icc_check_length output an error */
1542 else /* profile truncated */
1543 errmsg
= png_ptr
->zstream
.msg
;
1545 /* Release the stream */
1546 png_ptr
->zowner
= 0;
1549 else /* png_inflate_claim failed */
1550 errmsg
= png_ptr
->zstream
.msg
;
1554 errmsg
= "bad compression method"; /* or missing */
1558 errmsg
= "bad keyword";
1562 errmsg
= "too many profiles";
1564 /* Failure: the reason is in 'errmsg' */
1566 png_crc_finish(png_ptr
, length
);
1568 png_ptr
->colorspace
.flags
|= PNG_COLORSPACE_INVALID
;
1569 png_colorspace_sync(png_ptr
, info_ptr
);
1570 if (errmsg
!= NULL
) /* else already output */
1571 png_chunk_benign_error(png_ptr
, errmsg
);
1573 #endif /* READ_iCCP */
1575 #ifdef PNG_READ_sPLT_SUPPORTED
1577 png_handle_sPLT(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1578 /* Note: this does not properly handle chunks that are > 64K under DOS */
1580 png_bytep entry_start
, buffer
;
1581 png_sPLT_t new_palette
;
1583 png_uint_32 data_length
;
1585 png_uint_32 skip
= 0;
1589 png_debug(1, "in png_handle_sPLT");
1591 #ifdef PNG_USER_LIMITS_SUPPORTED
1592 if (png_ptr
->user_chunk_cache_max
!= 0)
1594 if (png_ptr
->user_chunk_cache_max
== 1)
1596 png_crc_finish(png_ptr
, length
);
1600 if (--png_ptr
->user_chunk_cache_max
== 1)
1602 png_warning(png_ptr
, "No space in chunk cache for sPLT");
1603 png_crc_finish(png_ptr
, length
);
1609 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1610 png_chunk_error(png_ptr
, "missing IHDR");
1612 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
1614 png_crc_finish(png_ptr
, length
);
1615 png_chunk_benign_error(png_ptr
, "out of place");
1619 #ifdef PNG_MAX_MALLOC_64K
1620 if (length
> 65535U)
1622 png_crc_finish(png_ptr
, length
);
1623 png_chunk_benign_error(png_ptr
, "too large to fit in memory");
1628 buffer
= png_read_buffer(png_ptr
, length
+1, 2/*silent*/);
1631 png_crc_finish(png_ptr
, length
);
1632 png_chunk_benign_error(png_ptr
, "out of memory");
1637 /* WARNING: this may break if size_t is less than 32 bits; it is assumed
1638 * that the PNG_MAX_MALLOC_64K test is enabled in this case, but this is a
1639 * potential breakage point if the types in pngconf.h aren't exactly right.
1641 png_crc_read(png_ptr
, buffer
, length
);
1643 if (png_crc_finish(png_ptr
, skip
) != 0)
1648 for (entry_start
= buffer
; *entry_start
; entry_start
++)
1649 /* Empty loop to find end of name */ ;
1653 /* A sample depth should follow the separator, and we should be on it */
1654 if (entry_start
> buffer
+ length
- 2)
1656 png_warning(png_ptr
, "malformed sPLT chunk");
1660 new_palette
.depth
= *entry_start
++;
1661 entry_size
= (new_palette
.depth
== 8 ? 6 : 10);
1662 /* This must fit in a png_uint_32 because it is derived from the original
1663 * chunk data length.
1665 data_length
= length
- (png_uint_32
)(entry_start
- buffer
);
1667 /* Integrity-check the data length */
1668 if ((data_length
% entry_size
) != 0)
1670 png_warning(png_ptr
, "sPLT chunk has bad length");
1674 dl
= (png_int_32
)(data_length
/ entry_size
);
1675 max_dl
= PNG_SIZE_MAX
/ (sizeof (png_sPLT_entry
));
1679 png_warning(png_ptr
, "sPLT chunk too long");
1683 new_palette
.nentries
= (png_int_32
)(data_length
/ entry_size
);
1685 new_palette
.entries
= (png_sPLT_entryp
)png_malloc_warn(
1686 png_ptr
, new_palette
.nentries
* (sizeof (png_sPLT_entry
)));
1688 if (new_palette
.entries
== NULL
)
1690 png_warning(png_ptr
, "sPLT chunk requires too much memory");
1694 #ifdef PNG_POINTER_INDEXING_SUPPORTED
1695 for (i
= 0; i
< new_palette
.nentries
; i
++)
1697 pp
= new_palette
.entries
+ i
;
1699 if (new_palette
.depth
== 8)
1701 pp
->red
= *entry_start
++;
1702 pp
->green
= *entry_start
++;
1703 pp
->blue
= *entry_start
++;
1704 pp
->alpha
= *entry_start
++;
1709 pp
->red
= png_get_uint_16(entry_start
); entry_start
+= 2;
1710 pp
->green
= png_get_uint_16(entry_start
); entry_start
+= 2;
1711 pp
->blue
= png_get_uint_16(entry_start
); entry_start
+= 2;
1712 pp
->alpha
= png_get_uint_16(entry_start
); entry_start
+= 2;
1715 pp
->frequency
= png_get_uint_16(entry_start
); entry_start
+= 2;
1718 pp
= new_palette
.entries
;
1720 for (i
= 0; i
< new_palette
.nentries
; i
++)
1723 if (new_palette
.depth
== 8)
1725 pp
[i
].red
= *entry_start
++;
1726 pp
[i
].green
= *entry_start
++;
1727 pp
[i
].blue
= *entry_start
++;
1728 pp
[i
].alpha
= *entry_start
++;
1733 pp
[i
].red
= png_get_uint_16(entry_start
); entry_start
+= 2;
1734 pp
[i
].green
= png_get_uint_16(entry_start
); entry_start
+= 2;
1735 pp
[i
].blue
= png_get_uint_16(entry_start
); entry_start
+= 2;
1736 pp
[i
].alpha
= png_get_uint_16(entry_start
); entry_start
+= 2;
1739 pp
[i
].frequency
= png_get_uint_16(entry_start
); entry_start
+= 2;
1743 /* Discard all chunk data except the name and stash that */
1744 new_palette
.name
= (png_charp
)buffer
;
1746 png_set_sPLT(png_ptr
, info_ptr
, &new_palette
, 1);
1748 png_free(png_ptr
, new_palette
.entries
);
1750 #endif /* READ_sPLT */
1752 #ifdef PNG_READ_tRNS_SUPPORTED
1754 png_handle_tRNS(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1756 png_byte readbuf
[PNG_MAX_PALETTE_LENGTH
];
1758 png_debug(1, "in png_handle_tRNS");
1760 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1761 png_chunk_error(png_ptr
, "missing IHDR");
1763 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
1765 png_crc_finish(png_ptr
, length
);
1766 png_chunk_benign_error(png_ptr
, "out of place");
1770 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_tRNS
) != 0)
1772 png_crc_finish(png_ptr
, length
);
1773 png_chunk_benign_error(png_ptr
, "duplicate");
1777 if (png_ptr
->color_type
== PNG_COLOR_TYPE_GRAY
)
1783 png_crc_finish(png_ptr
, length
);
1784 png_chunk_benign_error(png_ptr
, "invalid");
1788 png_crc_read(png_ptr
, buf
, 2);
1789 png_ptr
->num_trans
= 1;
1790 png_ptr
->trans_color
.gray
= png_get_uint_16(buf
);
1793 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_RGB
)
1799 png_crc_finish(png_ptr
, length
);
1800 png_chunk_benign_error(png_ptr
, "invalid");
1804 png_crc_read(png_ptr
, buf
, length
);
1805 png_ptr
->num_trans
= 1;
1806 png_ptr
->trans_color
.red
= png_get_uint_16(buf
);
1807 png_ptr
->trans_color
.green
= png_get_uint_16(buf
+ 2);
1808 png_ptr
->trans_color
.blue
= png_get_uint_16(buf
+ 4);
1811 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
1813 if ((png_ptr
->mode
& PNG_HAVE_PLTE
) == 0)
1815 /* TODO: is this actually an error in the ISO spec? */
1816 png_crc_finish(png_ptr
, length
);
1817 png_chunk_benign_error(png_ptr
, "out of place");
1821 if (length
> png_ptr
->num_palette
||
1822 length
> (unsigned int) PNG_MAX_PALETTE_LENGTH
||
1825 png_crc_finish(png_ptr
, length
);
1826 png_chunk_benign_error(png_ptr
, "invalid");
1830 png_crc_read(png_ptr
, readbuf
, length
);
1831 png_ptr
->num_trans
= (png_uint_16
)length
;
1836 png_crc_finish(png_ptr
, length
);
1837 png_chunk_benign_error(png_ptr
, "invalid with alpha channel");
1841 if (png_crc_finish(png_ptr
, 0) != 0)
1843 png_ptr
->num_trans
= 0;
1847 /* TODO: this is a horrible side effect in the palette case because the
1848 * png_struct ends up with a pointer to the tRNS buffer owned by the
1849 * png_info. Fix this.
1851 png_set_tRNS(png_ptr
, info_ptr
, readbuf
, png_ptr
->num_trans
,
1852 &(png_ptr
->trans_color
));
1856 #ifdef PNG_READ_bKGD_SUPPORTED
1858 png_handle_bKGD(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1860 unsigned int truelen
;
1862 png_color_16 background
;
1864 png_debug(1, "in png_handle_bKGD");
1866 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1867 png_chunk_error(png_ptr
, "missing IHDR");
1869 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0 ||
1870 (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
&&
1871 (png_ptr
->mode
& PNG_HAVE_PLTE
) == 0))
1873 png_crc_finish(png_ptr
, length
);
1874 png_chunk_benign_error(png_ptr
, "out of place");
1878 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_bKGD
) != 0)
1880 png_crc_finish(png_ptr
, length
);
1881 png_chunk_benign_error(png_ptr
, "duplicate");
1885 if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
1888 else if ((png_ptr
->color_type
& PNG_COLOR_MASK_COLOR
) != 0)
1894 if (length
!= truelen
)
1896 png_crc_finish(png_ptr
, length
);
1897 png_chunk_benign_error(png_ptr
, "invalid");
1901 png_crc_read(png_ptr
, buf
, truelen
);
1903 if (png_crc_finish(png_ptr
, 0) != 0)
1906 /* We convert the index value into RGB components so that we can allow
1907 * arbitrary RGB values for background when we have transparency, and
1908 * so it is easy to determine the RGB values of the background color
1909 * from the info_ptr struct.
1911 if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
1913 background
.index
= buf
[0];
1915 if (info_ptr
!= NULL
&& info_ptr
->num_palette
!= 0)
1917 if (buf
[0] >= info_ptr
->num_palette
)
1919 png_chunk_benign_error(png_ptr
, "invalid index");
1923 background
.red
= (png_uint_16
)png_ptr
->palette
[buf
[0]].red
;
1924 background
.green
= (png_uint_16
)png_ptr
->palette
[buf
[0]].green
;
1925 background
.blue
= (png_uint_16
)png_ptr
->palette
[buf
[0]].blue
;
1929 background
.red
= background
.green
= background
.blue
= 0;
1931 background
.gray
= 0;
1934 else if ((png_ptr
->color_type
& PNG_COLOR_MASK_COLOR
) == 0) /* GRAY */
1936 background
.index
= 0;
1940 background
.gray
= png_get_uint_16(buf
);
1945 background
.index
= 0;
1946 background
.red
= png_get_uint_16(buf
);
1947 background
.green
= png_get_uint_16(buf
+ 2);
1948 background
.blue
= png_get_uint_16(buf
+ 4);
1949 background
.gray
= 0;
1952 png_set_bKGD(png_ptr
, info_ptr
, &background
);
1956 #ifdef PNG_READ_hIST_SUPPORTED
1958 png_handle_hIST(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1960 unsigned int num
, i
;
1961 png_uint_16 readbuf
[PNG_MAX_PALETTE_LENGTH
];
1963 png_debug(1, "in png_handle_hIST");
1965 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1966 png_chunk_error(png_ptr
, "missing IHDR");
1968 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0 ||
1969 (png_ptr
->mode
& PNG_HAVE_PLTE
) == 0)
1971 png_crc_finish(png_ptr
, length
);
1972 png_chunk_benign_error(png_ptr
, "out of place");
1976 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_hIST
) != 0)
1978 png_crc_finish(png_ptr
, length
);
1979 png_chunk_benign_error(png_ptr
, "duplicate");
1985 if (num
!= png_ptr
->num_palette
|| num
> (unsigned int) PNG_MAX_PALETTE_LENGTH
)
1987 png_crc_finish(png_ptr
, length
);
1988 png_chunk_benign_error(png_ptr
, "invalid");
1992 for (i
= 0; i
< num
; i
++)
1996 png_crc_read(png_ptr
, buf
, 2);
1997 readbuf
[i
] = png_get_uint_16(buf
);
2000 if (png_crc_finish(png_ptr
, 0) != 0)
2003 png_set_hIST(png_ptr
, info_ptr
, readbuf
);
2007 #ifdef PNG_READ_pHYs_SUPPORTED
2009 png_handle_pHYs(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2012 png_uint_32 res_x
, res_y
;
2015 png_debug(1, "in png_handle_pHYs");
2017 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2018 png_chunk_error(png_ptr
, "missing IHDR");
2020 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2022 png_crc_finish(png_ptr
, length
);
2023 png_chunk_benign_error(png_ptr
, "out of place");
2027 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_pHYs
) != 0)
2029 png_crc_finish(png_ptr
, length
);
2030 png_chunk_benign_error(png_ptr
, "duplicate");
2036 png_crc_finish(png_ptr
, length
);
2037 png_chunk_benign_error(png_ptr
, "invalid");
2041 png_crc_read(png_ptr
, buf
, 9);
2043 if (png_crc_finish(png_ptr
, 0) != 0)
2046 res_x
= png_get_uint_32(buf
);
2047 res_y
= png_get_uint_32(buf
+ 4);
2049 png_set_pHYs(png_ptr
, info_ptr
, res_x
, res_y
, unit_type
);
2053 #ifdef PNG_READ_oFFs_SUPPORTED
2055 png_handle_oFFs(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2058 png_int_32 offset_x
, offset_y
;
2061 png_debug(1, "in png_handle_oFFs");
2063 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2064 png_chunk_error(png_ptr
, "missing IHDR");
2066 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2068 png_crc_finish(png_ptr
, length
);
2069 png_chunk_benign_error(png_ptr
, "out of place");
2073 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_oFFs
) != 0)
2075 png_crc_finish(png_ptr
, length
);
2076 png_chunk_benign_error(png_ptr
, "duplicate");
2082 png_crc_finish(png_ptr
, length
);
2083 png_chunk_benign_error(png_ptr
, "invalid");
2087 png_crc_read(png_ptr
, buf
, 9);
2089 if (png_crc_finish(png_ptr
, 0) != 0)
2092 offset_x
= png_get_int_32(buf
);
2093 offset_y
= png_get_int_32(buf
+ 4);
2095 png_set_oFFs(png_ptr
, info_ptr
, offset_x
, offset_y
, unit_type
);
2099 #ifdef PNG_READ_pCAL_SUPPORTED
2100 /* Read the pCAL chunk (described in the PNG Extensions document) */
2102 png_handle_pCAL(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2105 png_byte type
, nparams
;
2106 png_bytep buffer
, buf
, units
, endptr
;
2110 png_debug(1, "in png_handle_pCAL");
2112 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2113 png_chunk_error(png_ptr
, "missing IHDR");
2115 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2117 png_crc_finish(png_ptr
, length
);
2118 png_chunk_benign_error(png_ptr
, "out of place");
2122 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_pCAL
) != 0)
2124 png_crc_finish(png_ptr
, length
);
2125 png_chunk_benign_error(png_ptr
, "duplicate");
2129 png_debug1(2, "Allocating and reading pCAL chunk data (%u bytes)",
2132 buffer
= png_read_buffer(png_ptr
, length
+1, 2/*silent*/);
2136 png_crc_finish(png_ptr
, length
);
2137 png_chunk_benign_error(png_ptr
, "out of memory");
2141 png_crc_read(png_ptr
, buffer
, length
);
2143 if (png_crc_finish(png_ptr
, 0) != 0)
2146 buffer
[length
] = 0; /* Null terminate the last string */
2148 png_debug(3, "Finding end of pCAL purpose string");
2149 for (buf
= buffer
; *buf
; buf
++)
2152 endptr
= buffer
+ length
;
2154 /* We need to have at least 12 bytes after the purpose string
2155 * in order to get the parameter information.
2157 if (endptr
<= buf
+ 12)
2159 png_chunk_benign_error(png_ptr
, "invalid");
2163 png_debug(3, "Reading pCAL X0, X1, type, nparams, and units");
2164 X0
= png_get_int_32((png_bytep
)buf
+1);
2165 X1
= png_get_int_32((png_bytep
)buf
+5);
2170 png_debug(3, "Checking pCAL equation type and number of parameters");
2171 /* Check that we have the right number of parameters for known
2174 if ((type
== PNG_EQUATION_LINEAR
&& nparams
!= 2) ||
2175 (type
== PNG_EQUATION_BASE_E
&& nparams
!= 3) ||
2176 (type
== PNG_EQUATION_ARBITRARY
&& nparams
!= 3) ||
2177 (type
== PNG_EQUATION_HYPERBOLIC
&& nparams
!= 4))
2179 png_chunk_benign_error(png_ptr
, "invalid parameter count");
2183 else if (type
>= PNG_EQUATION_LAST
)
2185 png_chunk_benign_error(png_ptr
, "unrecognized equation type");
2188 for (buf
= units
; *buf
; buf
++)
2189 /* Empty loop to move past the units string. */ ;
2191 png_debug(3, "Allocating pCAL parameters array");
2193 params
= png_voidcast(png_charpp
, png_malloc_warn(png_ptr
,
2194 nparams
* (sizeof (png_charp
))));
2198 png_chunk_benign_error(png_ptr
, "out of memory");
2202 /* Get pointers to the start of each parameter string. */
2203 for (i
= 0; i
< nparams
; i
++)
2205 buf
++; /* Skip the null string terminator from previous parameter. */
2207 png_debug1(3, "Reading pCAL parameter %d", i
);
2209 for (params
[i
] = (png_charp
)buf
; buf
<= endptr
&& *buf
!= 0; buf
++)
2210 /* Empty loop to move past each parameter string */ ;
2212 /* Make sure we haven't run out of data yet */
2215 png_free(png_ptr
, params
);
2216 png_chunk_benign_error(png_ptr
, "invalid data");
2221 png_set_pCAL(png_ptr
, info_ptr
, (png_charp
)buffer
, X0
, X1
, type
, nparams
,
2222 (png_charp
)units
, params
);
2224 png_free(png_ptr
, params
);
2228 #ifdef PNG_READ_sCAL_SUPPORTED
2229 /* Read the sCAL chunk */
2231 png_handle_sCAL(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2237 png_debug(1, "in png_handle_sCAL");
2239 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2240 png_chunk_error(png_ptr
, "missing IHDR");
2242 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2244 png_crc_finish(png_ptr
, length
);
2245 png_chunk_benign_error(png_ptr
, "out of place");
2249 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_sCAL
) != 0)
2251 png_crc_finish(png_ptr
, length
);
2252 png_chunk_benign_error(png_ptr
, "duplicate");
2256 /* Need unit type, width, \0, height: minimum 4 bytes */
2257 else if (length
< 4)
2259 png_crc_finish(png_ptr
, length
);
2260 png_chunk_benign_error(png_ptr
, "invalid");
2264 png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)",
2267 buffer
= png_read_buffer(png_ptr
, length
+1, 2/*silent*/);
2271 png_chunk_benign_error(png_ptr
, "out of memory");
2272 png_crc_finish(png_ptr
, length
);
2276 png_crc_read(png_ptr
, buffer
, length
);
2277 buffer
[length
] = 0; /* Null terminate the last string */
2279 if (png_crc_finish(png_ptr
, 0) != 0)
2282 /* Validate the unit. */
2283 if (buffer
[0] != 1 && buffer
[0] != 2)
2285 png_chunk_benign_error(png_ptr
, "invalid unit");
2289 /* Validate the ASCII numbers, need two ASCII numbers separated by
2290 * a '\0' and they need to fit exactly in the chunk data.
2295 if (png_check_fp_number((png_const_charp
)buffer
, length
, &state
, &i
) == 0 ||
2296 i
>= length
|| buffer
[i
++] != 0)
2297 png_chunk_benign_error(png_ptr
, "bad width format");
2299 else if (PNG_FP_IS_POSITIVE(state
) == 0)
2300 png_chunk_benign_error(png_ptr
, "non-positive width");
2304 png_size_t heighti
= i
;
2307 if (png_check_fp_number((png_const_charp
)buffer
, length
,
2308 &state
, &i
) == 0 || i
!= length
)
2309 png_chunk_benign_error(png_ptr
, "bad height format");
2311 else if (PNG_FP_IS_POSITIVE(state
) == 0)
2312 png_chunk_benign_error(png_ptr
, "non-positive height");
2315 /* This is the (only) success case. */
2316 png_set_sCAL_s(png_ptr
, info_ptr
, buffer
[0],
2317 (png_charp
)buffer
+1, (png_charp
)buffer
+heighti
);
2322 #ifdef PNG_READ_tIME_SUPPORTED
2324 png_handle_tIME(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2329 png_debug(1, "in png_handle_tIME");
2331 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2332 png_chunk_error(png_ptr
, "missing IHDR");
2334 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_tIME
) != 0)
2336 png_crc_finish(png_ptr
, length
);
2337 png_chunk_benign_error(png_ptr
, "duplicate");
2341 if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2342 png_ptr
->mode
|= PNG_AFTER_IDAT
;
2346 png_crc_finish(png_ptr
, length
);
2347 png_chunk_benign_error(png_ptr
, "invalid");
2351 png_crc_read(png_ptr
, buf
, 7);
2353 if (png_crc_finish(png_ptr
, 0) != 0)
2356 mod_time
.second
= buf
[6];
2357 mod_time
.minute
= buf
[5];
2358 mod_time
.hour
= buf
[4];
2359 mod_time
.day
= buf
[3];
2360 mod_time
.month
= buf
[2];
2361 mod_time
.year
= png_get_uint_16(buf
);
2363 png_set_tIME(png_ptr
, info_ptr
, &mod_time
);
2367 #ifdef PNG_READ_tEXt_SUPPORTED
2368 /* Note: this does not properly handle chunks that are > 64K under DOS */
2370 png_handle_tEXt(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2376 png_uint_32 skip
= 0;
2378 png_debug(1, "in png_handle_tEXt");
2380 #ifdef PNG_USER_LIMITS_SUPPORTED
2381 if (png_ptr
->user_chunk_cache_max
!= 0)
2383 if (png_ptr
->user_chunk_cache_max
== 1)
2385 png_crc_finish(png_ptr
, length
);
2389 if (--png_ptr
->user_chunk_cache_max
== 1)
2391 png_crc_finish(png_ptr
, length
);
2392 png_chunk_benign_error(png_ptr
, "no space in chunk cache");
2398 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2399 png_chunk_error(png_ptr
, "missing IHDR");
2401 if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2402 png_ptr
->mode
|= PNG_AFTER_IDAT
;
2404 #ifdef PNG_MAX_MALLOC_64K
2405 if (length
> 65535U)
2407 png_crc_finish(png_ptr
, length
);
2408 png_chunk_benign_error(png_ptr
, "too large to fit in memory");
2413 buffer
= png_read_buffer(png_ptr
, length
+1, 1/*warn*/);
2417 png_chunk_benign_error(png_ptr
, "out of memory");
2421 png_crc_read(png_ptr
, buffer
, length
);
2423 if (png_crc_finish(png_ptr
, skip
) != 0)
2426 key
= (png_charp
)buffer
;
2429 for (text
= key
; *text
; text
++)
2430 /* Empty loop to find end of key */ ;
2432 if (text
!= key
+ length
)
2435 text_info
.compression
= PNG_TEXT_COMPRESSION_NONE
;
2436 text_info
.key
= key
;
2437 text_info
.lang
= NULL
;
2438 text_info
.lang_key
= NULL
;
2439 text_info
.itxt_length
= 0;
2440 text_info
.text
= text
;
2441 text_info
.text_length
= strlen(text
);
2443 if (png_set_text_2(png_ptr
, info_ptr
, &text_info
, 1) != 0)
2444 png_warning(png_ptr
, "Insufficient memory to process text chunk");
2448 #ifdef PNG_READ_zTXt_SUPPORTED
2449 /* Note: this does not correctly handle chunks that are > 64K under DOS */
2451 png_handle_zTXt(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2453 png_const_charp errmsg
= NULL
;
2455 png_uint_32 keyword_length
;
2457 png_debug(1, "in png_handle_zTXt");
2459 #ifdef PNG_USER_LIMITS_SUPPORTED
2460 if (png_ptr
->user_chunk_cache_max
!= 0)
2462 if (png_ptr
->user_chunk_cache_max
== 1)
2464 png_crc_finish(png_ptr
, length
);
2468 if (--png_ptr
->user_chunk_cache_max
== 1)
2470 png_crc_finish(png_ptr
, length
);
2471 png_chunk_benign_error(png_ptr
, "no space in chunk cache");
2477 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2478 png_chunk_error(png_ptr
, "missing IHDR");
2480 if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2481 png_ptr
->mode
|= PNG_AFTER_IDAT
;
2483 buffer
= png_read_buffer(png_ptr
, length
, 2/*silent*/);
2487 png_crc_finish(png_ptr
, length
);
2488 png_chunk_benign_error(png_ptr
, "out of memory");
2492 png_crc_read(png_ptr
, buffer
, length
);
2494 if (png_crc_finish(png_ptr
, 0) != 0)
2497 /* TODO: also check that the keyword contents match the spec! */
2498 for (keyword_length
= 0;
2499 keyword_length
< length
&& buffer
[keyword_length
] != 0;
2501 /* Empty loop to find end of name */ ;
2503 if (keyword_length
> 79 || keyword_length
< 1)
2504 errmsg
= "bad keyword";
2506 /* zTXt must have some LZ data after the keyword, although it may expand to
2507 * zero bytes; we need a '\0' at the end of the keyword, the compression type
2510 else if (keyword_length
+ 3 > length
)
2511 errmsg
= "truncated";
2513 else if (buffer
[keyword_length
+1] != PNG_COMPRESSION_TYPE_BASE
)
2514 errmsg
= "unknown compression type";
2518 png_alloc_size_t uncompressed_length
= PNG_SIZE_MAX
;
2520 /* TODO: at present png_decompress_chunk imposes a single application
2521 * level memory limit, this should be split to different values for iCCP
2524 if (png_decompress_chunk(png_ptr
, length
, keyword_length
+2,
2525 &uncompressed_length
, 1/*terminate*/) == Z_STREAM_END
)
2529 /* It worked; png_ptr->read_buffer now looks like a tEXt chunk except
2530 * for the extra compression type byte and the fact that it isn't
2531 * necessarily '\0' terminated.
2533 buffer
= png_ptr
->read_buffer
;
2534 buffer
[uncompressed_length
+(keyword_length
+2)] = 0;
2536 text
.compression
= PNG_TEXT_COMPRESSION_zTXt
;
2537 text
.key
= (png_charp
)buffer
;
2538 text
.text
= (png_charp
)(buffer
+ keyword_length
+2);
2539 text
.text_length
= uncompressed_length
;
2540 text
.itxt_length
= 0;
2542 text
.lang_key
= NULL
;
2544 if (png_set_text_2(png_ptr
, info_ptr
, &text
, 1) != 0)
2545 errmsg
= "insufficient memory";
2549 errmsg
= png_ptr
->zstream
.msg
;
2553 png_chunk_benign_error(png_ptr
, errmsg
);
2557 #ifdef PNG_READ_iTXt_SUPPORTED
2558 /* Note: this does not correctly handle chunks that are > 64K under DOS */
2560 png_handle_iTXt(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2562 png_const_charp errmsg
= NULL
;
2564 png_uint_32 prefix_length
;
2566 png_debug(1, "in png_handle_iTXt");
2568 #ifdef PNG_USER_LIMITS_SUPPORTED
2569 if (png_ptr
->user_chunk_cache_max
!= 0)
2571 if (png_ptr
->user_chunk_cache_max
== 1)
2573 png_crc_finish(png_ptr
, length
);
2577 if (--png_ptr
->user_chunk_cache_max
== 1)
2579 png_crc_finish(png_ptr
, length
);
2580 png_chunk_benign_error(png_ptr
, "no space in chunk cache");
2586 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2587 png_chunk_error(png_ptr
, "missing IHDR");
2589 if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2590 png_ptr
->mode
|= PNG_AFTER_IDAT
;
2592 buffer
= png_read_buffer(png_ptr
, length
+1, 1/*warn*/);
2596 png_crc_finish(png_ptr
, length
);
2597 png_chunk_benign_error(png_ptr
, "out of memory");
2601 png_crc_read(png_ptr
, buffer
, length
);
2603 if (png_crc_finish(png_ptr
, 0) != 0)
2606 /* First the keyword. */
2607 for (prefix_length
=0;
2608 prefix_length
< length
&& buffer
[prefix_length
] != 0;
2612 /* Perform a basic check on the keyword length here. */
2613 if (prefix_length
> 79 || prefix_length
< 1)
2614 errmsg
= "bad keyword";
2616 /* Expect keyword, compression flag, compression type, language, translated
2617 * keyword (both may be empty but are 0 terminated) then the text, which may
2620 else if (prefix_length
+ 5 > length
)
2621 errmsg
= "truncated";
2623 else if (buffer
[prefix_length
+1] == 0 ||
2624 (buffer
[prefix_length
+1] == 1 &&
2625 buffer
[prefix_length
+2] == PNG_COMPRESSION_TYPE_BASE
))
2627 int compressed
= buffer
[prefix_length
+1] != 0;
2628 png_uint_32 language_offset
, translated_keyword_offset
;
2629 png_alloc_size_t uncompressed_length
= 0;
2631 /* Now the language tag */
2633 language_offset
= prefix_length
;
2635 for (; prefix_length
< length
&& buffer
[prefix_length
] != 0;
2639 /* WARNING: the length may be invalid here, this is checked below. */
2640 translated_keyword_offset
= ++prefix_length
;
2642 for (; prefix_length
< length
&& buffer
[prefix_length
] != 0;
2646 /* prefix_length should now be at the trailing '\0' of the translated
2647 * keyword, but it may already be over the end. None of this arithmetic
2648 * can overflow because chunks are at most 2^31 bytes long, but on 16-bit
2649 * systems the available allocation may overflow.
2653 if (compressed
== 0 && prefix_length
<= length
)
2654 uncompressed_length
= length
- prefix_length
;
2656 else if (compressed
!= 0 && prefix_length
< length
)
2658 uncompressed_length
= PNG_SIZE_MAX
;
2660 /* TODO: at present png_decompress_chunk imposes a single application
2661 * level memory limit, this should be split to different values for
2662 * iCCP and text chunks.
2664 if (png_decompress_chunk(png_ptr
, length
, prefix_length
,
2665 &uncompressed_length
, 1/*terminate*/) == Z_STREAM_END
)
2666 buffer
= png_ptr
->read_buffer
;
2669 errmsg
= png_ptr
->zstream
.msg
;
2673 errmsg
= "truncated";
2679 buffer
[uncompressed_length
+prefix_length
] = 0;
2681 if (compressed
== 0)
2682 text
.compression
= PNG_ITXT_COMPRESSION_NONE
;
2685 text
.compression
= PNG_ITXT_COMPRESSION_zTXt
;
2687 text
.key
= (png_charp
)buffer
;
2688 text
.lang
= (png_charp
)buffer
+ language_offset
;
2689 text
.lang_key
= (png_charp
)buffer
+ translated_keyword_offset
;
2690 text
.text
= (png_charp
)buffer
+ prefix_length
;
2691 text
.text_length
= 0;
2692 text
.itxt_length
= uncompressed_length
;
2694 if (png_set_text_2(png_ptr
, info_ptr
, &text
, 1) != 0)
2695 errmsg
= "insufficient memory";
2700 errmsg
= "bad compression info";
2703 png_chunk_benign_error(png_ptr
, errmsg
);
2707 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
2708 /* Utility function for png_handle_unknown; set up png_ptr::unknown_chunk */
2710 png_cache_unknown_chunk(png_structrp png_ptr
, png_uint_32 length
)
2712 png_alloc_size_t limit
= PNG_SIZE_MAX
;
2714 if (png_ptr
->unknown_chunk
.data
!= NULL
)
2716 png_free(png_ptr
, png_ptr
->unknown_chunk
.data
);
2717 png_ptr
->unknown_chunk
.data
= NULL
;
2720 # ifdef PNG_SET_USER_LIMITS_SUPPORTED
2721 if (png_ptr
->user_chunk_malloc_max
> 0 &&
2722 png_ptr
->user_chunk_malloc_max
< limit
)
2723 limit
= png_ptr
->user_chunk_malloc_max
;
2725 # elif PNG_USER_CHUNK_MALLOC_MAX > 0
2726 if (PNG_USER_CHUNK_MALLOC_MAX
< limit
)
2727 limit
= PNG_USER_CHUNK_MALLOC_MAX
;
2730 if (length
<= limit
)
2732 PNG_CSTRING_FROM_CHUNK(png_ptr
->unknown_chunk
.name
, png_ptr
->chunk_name
);
2733 /* The following is safe because of the PNG_SIZE_MAX init above */
2734 png_ptr
->unknown_chunk
.size
= (png_size_t
)length
/*SAFE*/;
2735 /* 'mode' is a flag array, only the bottom four bits matter here */
2736 png_ptr
->unknown_chunk
.location
= (png_byte
)png_ptr
->mode
/*SAFE*/;
2739 png_ptr
->unknown_chunk
.data
= NULL
;
2743 /* Do a 'warn' here - it is handled below. */
2744 png_ptr
->unknown_chunk
.data
= png_voidcast(png_bytep
,
2745 png_malloc_warn(png_ptr
, length
));
2749 if (png_ptr
->unknown_chunk
.data
== NULL
&& length
> 0)
2751 /* This is benign because we clean up correctly */
2752 png_crc_finish(png_ptr
, length
);
2753 png_chunk_benign_error(png_ptr
, "unknown chunk exceeds memory limits");
2760 png_crc_read(png_ptr
, png_ptr
->unknown_chunk
.data
, length
);
2761 png_crc_finish(png_ptr
, 0);
2765 #endif /* READ_UNKNOWN_CHUNKS */
2767 /* Handle an unknown, or known but disabled, chunk */
2769 png_handle_unknown(png_structrp png_ptr
, png_inforp info_ptr
,
2770 png_uint_32 length
, int keep
)
2772 int handled
= 0; /* the chunk was handled */
2774 png_debug(1, "in png_handle_unknown");
2776 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
2777 /* NOTE: this code is based on the code in libpng-1.4.12 except for fixing
2778 * the bug which meant that setting a non-default behavior for a specific
2779 * chunk would be ignored (the default was always used unless a user
2780 * callback was installed).
2782 * 'keep' is the value from the png_chunk_unknown_handling, the setting for
2783 * this specific chunk_name, if PNG_HANDLE_AS_UNKNOWN_SUPPORTED, if not it
2784 * will always be PNG_HANDLE_CHUNK_AS_DEFAULT and it needs to be set here.
2785 * This is just an optimization to avoid multiple calls to the lookup
2788 # ifndef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
2789 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
2790 keep
= png_chunk_unknown_handling(png_ptr
, png_ptr
->chunk_name
);
2794 /* One of the following methods will read the chunk or skip it (at least one
2795 * of these is always defined because this is the only way to switch on
2796 * PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
2798 # ifdef PNG_READ_USER_CHUNKS_SUPPORTED
2799 /* The user callback takes precedence over the chunk keep value, but the
2800 * keep value is still required to validate a save of a critical chunk.
2802 if (png_ptr
->read_user_chunk_fn
!= NULL
)
2804 if (png_cache_unknown_chunk(png_ptr
, length
) != 0)
2806 /* Callback to user unknown chunk handler */
2807 int ret
= (*(png_ptr
->read_user_chunk_fn
))(png_ptr
,
2808 &png_ptr
->unknown_chunk
);
2811 * negative: An error occurred; png_chunk_error will be called.
2812 * zero: The chunk was not handled, the chunk will be discarded
2813 * unless png_set_keep_unknown_chunks has been used to set
2814 * a 'keep' behavior for this particular chunk, in which
2815 * case that will be used. A critical chunk will cause an
2816 * error at this point unless it is to be saved.
2817 * positive: The chunk was handled, libpng will ignore/discard it.
2820 png_chunk_error(png_ptr
, "error in user chunk");
2824 /* If the keep value is 'default' or 'never' override it, but
2825 * still error out on critical chunks unless the keep value is
2826 * 'always' While this is weird it is the behavior in 1.4.12.
2827 * A possible improvement would be to obey the value set for the
2828 * chunk, but this would be an API change that would probably
2829 * damage some applications.
2831 * The png_app_warning below catches the case that matters, where
2832 * the application has not set specific save or ignore for this
2833 * chunk or global save or ignore.
2835 if (keep
< PNG_HANDLE_CHUNK_IF_SAFE
)
2837 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
2838 if (png_ptr
->unknown_default
< PNG_HANDLE_CHUNK_IF_SAFE
)
2840 png_chunk_warning(png_ptr
, "Saving unknown chunk:");
2841 png_app_warning(png_ptr
,
2842 "forcing save of an unhandled chunk;"
2843 " please call png_set_keep_unknown_chunks");
2844 /* with keep = PNG_HANDLE_CHUNK_IF_SAFE */
2847 keep
= PNG_HANDLE_CHUNK_IF_SAFE
;
2851 else /* chunk was handled */
2854 /* Critical chunks can be safely discarded at this point. */
2855 keep
= PNG_HANDLE_CHUNK_NEVER
;
2860 keep
= PNG_HANDLE_CHUNK_NEVER
; /* insufficient memory */
2864 /* Use the SAVE_UNKNOWN_CHUNKS code or skip the chunk */
2865 # endif /* READ_USER_CHUNKS */
2867 # ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
2869 /* keep is currently just the per-chunk setting, if there was no
2870 * setting change it to the global default now (not that this may
2871 * still be AS_DEFAULT) then obtain the cache of the chunk if required,
2872 * if not simply skip the chunk.
2874 if (keep
== PNG_HANDLE_CHUNK_AS_DEFAULT
)
2875 keep
= png_ptr
->unknown_default
;
2877 if (keep
== PNG_HANDLE_CHUNK_ALWAYS
||
2878 (keep
== PNG_HANDLE_CHUNK_IF_SAFE
&&
2879 PNG_CHUNK_ANCILLARY(png_ptr
->chunk_name
)))
2881 if (png_cache_unknown_chunk(png_ptr
, length
) == 0)
2882 keep
= PNG_HANDLE_CHUNK_NEVER
;
2886 png_crc_finish(png_ptr
, length
);
2889 # ifndef PNG_READ_USER_CHUNKS_SUPPORTED
2890 # error no method to support READ_UNKNOWN_CHUNKS
2894 /* If here there is no read callback pointer set and no support is
2895 * compiled in to just save the unknown chunks, so simply skip this
2896 * chunk. If 'keep' is something other than AS_DEFAULT or NEVER then
2897 * the app has erroneously asked for unknown chunk saving when there
2900 if (keep
> PNG_HANDLE_CHUNK_NEVER
)
2901 png_app_error(png_ptr
, "no unknown chunk support available");
2903 png_crc_finish(png_ptr
, length
);
2907 # ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
2908 /* Now store the chunk in the chunk list if appropriate, and if the limits
2911 if (keep
== PNG_HANDLE_CHUNK_ALWAYS
||
2912 (keep
== PNG_HANDLE_CHUNK_IF_SAFE
&&
2913 PNG_CHUNK_ANCILLARY(png_ptr
->chunk_name
)))
2915 # ifdef PNG_USER_LIMITS_SUPPORTED
2916 switch (png_ptr
->user_chunk_cache_max
)
2919 png_ptr
->user_chunk_cache_max
= 1;
2920 png_chunk_benign_error(png_ptr
, "no space in chunk cache");
2923 /* NOTE: prior to 1.6.0 this case resulted in an unknown critical
2924 * chunk being skipped, now there will be a hard error below.
2928 default: /* not at limit */
2929 --(png_ptr
->user_chunk_cache_max
);
2931 case 0: /* no limit */
2932 # endif /* USER_LIMITS */
2933 /* Here when the limit isn't reached or when limits are compiled
2934 * out; store the chunk.
2936 png_set_unknown_chunks(png_ptr
, info_ptr
,
2937 &png_ptr
->unknown_chunk
, 1);
2939 # ifdef PNG_USER_LIMITS_SUPPORTED
2944 # else /* no store support: the chunk must be handled by the user callback */
2945 PNG_UNUSED(info_ptr
)
2948 /* Regardless of the error handling below the cached data (if any) can be
2949 * freed now. Notice that the data is not freed if there is a png_error, but
2950 * it will be freed by destroy_read_struct.
2952 if (png_ptr
->unknown_chunk
.data
!= NULL
)
2953 png_free(png_ptr
, png_ptr
->unknown_chunk
.data
);
2954 png_ptr
->unknown_chunk
.data
= NULL
;
2956 #else /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */
2957 /* There is no support to read an unknown chunk, so just skip it. */
2958 png_crc_finish(png_ptr
, length
);
2959 PNG_UNUSED(info_ptr
)
2961 #endif /* !READ_UNKNOWN_CHUNKS */
2963 /* Check for unhandled critical chunks */
2964 if (handled
== 0 && PNG_CHUNK_CRITICAL(png_ptr
->chunk_name
))
2965 png_chunk_error(png_ptr
, "unhandled critical chunk");
2968 /* This function is called to verify that a chunk name is valid.
2969 * This function can't have the "critical chunk check" incorporated
2970 * into it, since in the future we will need to be able to call user
2971 * functions to handle unknown critical chunks after we check that
2972 * the chunk name itself is valid.
2975 /* Bit hacking: the test for an invalid byte in the 4 byte chunk name is:
2977 * ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
2981 png_check_chunk_name(png_structrp png_ptr
, png_uint_32 chunk_name
)
2985 png_debug(1, "in png_check_chunk_name");
2987 for (i
=1; i
<=4; ++i
)
2989 int c
= chunk_name
& 0xff;
2991 if (c
< 65 || c
> 122 || (c
> 90 && c
< 97))
2992 png_chunk_error(png_ptr
, "invalid chunk type");
2998 /* Combines the row recently read in with the existing pixels in the row. This
2999 * routine takes care of alpha and transparency if requested. This routine also
3000 * handles the two methods of progressive display of interlaced images,
3001 * depending on the 'display' value; if 'display' is true then the whole row
3002 * (dp) is filled from the start by replicating the available pixels. If
3003 * 'display' is false only those pixels present in the pass are filled in.
3006 png_combine_row(png_const_structrp png_ptr
, png_bytep dp
, int display
)
3008 unsigned int pixel_depth
= png_ptr
->transformed_pixel_depth
;
3009 png_const_bytep sp
= png_ptr
->row_buf
+ 1;
3010 png_alloc_size_t row_width
= png_ptr
->width
;
3011 unsigned int pass
= png_ptr
->pass
;
3012 png_bytep end_ptr
= 0;
3013 png_byte end_byte
= 0;
3014 unsigned int end_mask
;
3016 png_debug(1, "in png_combine_row");
3018 /* Added in 1.5.6: it should not be possible to enter this routine until at
3019 * least one row has been read from the PNG data and transformed.
3021 if (pixel_depth
== 0)
3022 png_error(png_ptr
, "internal row logic error");
3024 /* Added in 1.5.4: the pixel depth should match the information returned by
3025 * any call to png_read_update_info at this point. Do not continue if we got
3028 if (png_ptr
->info_rowbytes
!= 0 && png_ptr
->info_rowbytes
!=
3029 PNG_ROWBYTES(pixel_depth
, row_width
))
3030 png_error(png_ptr
, "internal row size calculation error");
3032 /* Don't expect this to ever happen: */
3034 png_error(png_ptr
, "internal row width error");
3036 /* Preserve the last byte in cases where only part of it will be overwritten,
3037 * the multiply below may overflow, we don't care because ANSI-C guarantees
3038 * we get the low bits.
3040 end_mask
= (pixel_depth
* row_width
) & 7;
3043 /* end_ptr == NULL is a flag to say do nothing */
3044 end_ptr
= dp
+ PNG_ROWBYTES(pixel_depth
, row_width
) - 1;
3045 end_byte
= *end_ptr
;
3046 # ifdef PNG_READ_PACKSWAP_SUPPORTED
3047 if ((png_ptr
->transformations
& PNG_PACKSWAP
) != 0)
3048 /* little-endian byte */
3049 end_mask
= 0xff << end_mask
;
3051 else /* big-endian byte */
3053 end_mask
= 0xff >> end_mask
;
3054 /* end_mask is now the bits to *keep* from the destination row */
3057 /* For non-interlaced images this reduces to a memcpy(). A memcpy()
3058 * will also happen if interlacing isn't supported or if the application
3059 * does not call png_set_interlace_handling(). In the latter cases the
3060 * caller just gets a sequence of the unexpanded rows from each interlace
3063 #ifdef PNG_READ_INTERLACING_SUPPORTED
3064 if (png_ptr
->interlaced
!= 0 &&
3065 (png_ptr
->transformations
& PNG_INTERLACE
) != 0 &&
3066 pass
< 6 && (display
== 0 ||
3067 /* The following copies everything for 'display' on passes 0, 2 and 4. */
3068 (display
== 1 && (pass
& 1) != 0)))
3070 /* Narrow images may have no bits in a pass; the caller should handle
3071 * this, but this test is cheap:
3073 if (row_width
<= PNG_PASS_START_COL(pass
))
3076 if (pixel_depth
< 8)
3078 /* For pixel depths up to 4 bpp the 8-pixel mask can be expanded to fit
3079 * into 32 bits, then a single loop over the bytes using the four byte
3080 * values in the 32-bit mask can be used. For the 'display' option the
3081 * expanded mask may also not require any masking within a byte. To
3082 * make this work the PACKSWAP option must be taken into account - it
3083 * simply requires the pixels to be reversed in each byte.
3085 * The 'regular' case requires a mask for each of the first 6 passes,
3086 * the 'display' case does a copy for the even passes in the range
3087 * 0..6. This has already been handled in the test above.
3089 * The masks are arranged as four bytes with the first byte to use in
3090 * the lowest bits (little-endian) regardless of the order (PACKSWAP or
3091 * not) of the pixels in each byte.
3093 * NOTE: the whole of this logic depends on the caller of this function
3094 * only calling it on rows appropriate to the pass. This function only
3095 * understands the 'x' logic; the 'y' logic is handled by the caller.
3097 * The following defines allow generation of compile time constant bit
3098 * masks for each pixel depth and each possibility of swapped or not
3099 * swapped bytes. Pass 'p' is in the range 0..6; 'x', a pixel index,
3100 * is in the range 0..7; and the result is 1 if the pixel is to be
3101 * copied in the pass, 0 if not. 'S' is for the sparkle method, 'B'
3102 * for the block method.
3104 * With some compilers a compile time expression of the general form:
3106 * (shift >= 32) ? (a >> (shift-32)) : (b >> shift)
3108 * Produces warnings with values of 'shift' in the range 33 to 63
3109 * because the right hand side of the ?: expression is evaluated by
3110 * the compiler even though it isn't used. Microsoft Visual C (various
3111 * versions) and the Intel C compiler are known to do this. To avoid
3112 * this the following macros are used in 1.5.6. This is a temporary
3113 * solution to avoid destabilizing the code during the release process.
3115 # if PNG_USE_COMPILE_TIME_MASKS
3116 # define PNG_LSR(x,s) ((x)>>((s) & 0x1f))
3117 # define PNG_LSL(x,s) ((x)<<((s) & 0x1f))
3119 # define PNG_LSR(x,s) ((x)>>(s))
3120 # define PNG_LSL(x,s) ((x)<<(s))
3122 # define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\
3123 PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1)
3124 # define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\
3125 PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1)
3127 /* Return a mask for pass 'p' pixel 'x' at depth 'd'. The mask is
3128 * little endian - the first pixel is at bit 0 - however the extra
3129 * parameter 's' can be set to cause the mask position to be swapped
3130 * within each byte, to match the PNG format. This is done by XOR of
3131 * the shift with 7, 6 or 4 for bit depths 1, 2 and 4.
3133 # define PIXEL_MASK(p,x,d,s) \
3134 (PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0))))
3136 /* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask.
3138 # define S_MASKx(p,x,d,s) (S_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
3139 # define B_MASKx(p,x,d,s) (B_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
3141 /* Combine 8 of these to get the full mask. For the 1-bpp and 2-bpp
3142 * cases the result needs replicating, for the 4-bpp case the above
3143 * generates a full 32 bits.
3145 # define MASK_EXPAND(m,d) ((m)*((d)==1?0x01010101:((d)==2?0x00010001:1)))
3147 # define S_MASK(p,d,s) MASK_EXPAND(S_MASKx(p,0,d,s) + S_MASKx(p,1,d,s) +\
3148 S_MASKx(p,2,d,s) + S_MASKx(p,3,d,s) + S_MASKx(p,4,d,s) +\
3149 S_MASKx(p,5,d,s) + S_MASKx(p,6,d,s) + S_MASKx(p,7,d,s), d)
3151 # define B_MASK(p,d,s) MASK_EXPAND(B_MASKx(p,0,d,s) + B_MASKx(p,1,d,s) +\
3152 B_MASKx(p,2,d,s) + B_MASKx(p,3,d,s) + B_MASKx(p,4,d,s) +\
3153 B_MASKx(p,5,d,s) + B_MASKx(p,6,d,s) + B_MASKx(p,7,d,s), d)
3155 #if PNG_USE_COMPILE_TIME_MASKS
3156 /* Utility macros to construct all the masks for a depth/swap
3157 * combination. The 's' parameter says whether the format is PNG
3158 * (big endian bytes) or not. Only the three odd-numbered passes are
3159 * required for the display/block algorithm.
3161 # define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\
3162 S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) }
3164 # define B_MASKS(d,s) { B_MASK(1,d,s), B_MASK(3,d,s), B_MASK(5,d,s) }
3166 # define DEPTH_INDEX(d) ((d)==1?0:((d)==2?1:2))
3168 /* Hence the pre-compiled masks indexed by PACKSWAP (or not), depth and
3171 static PNG_CONST png_uint_32 row_mask
[2/*PACKSWAP*/][3/*depth*/][6] =
3173 /* Little-endian byte masks for PACKSWAP */
3174 { S_MASKS(1,0), S_MASKS(2,0), S_MASKS(4,0) },
3175 /* Normal (big-endian byte) masks - PNG format */
3176 { S_MASKS(1,1), S_MASKS(2,1), S_MASKS(4,1) }
3179 /* display_mask has only three entries for the odd passes, so index by
3182 static PNG_CONST png_uint_32 display_mask
[2][3][3] =
3184 /* Little-endian byte masks for PACKSWAP */
3185 { B_MASKS(1,0), B_MASKS(2,0), B_MASKS(4,0) },
3186 /* Normal (big-endian byte) masks - PNG format */
3187 { B_MASKS(1,1), B_MASKS(2,1), B_MASKS(4,1) }
3190 # define MASK(pass,depth,display,png)\
3191 ((display)?display_mask[png][DEPTH_INDEX(depth)][pass>>1]:\
3192 row_mask[png][DEPTH_INDEX(depth)][pass])
3194 #else /* !PNG_USE_COMPILE_TIME_MASKS */
3195 /* This is the runtime alternative: it seems unlikely that this will
3196 * ever be either smaller or faster than the compile time approach.
3198 # define MASK(pass,depth,display,png)\
3199 ((display)?B_MASK(pass,depth,png):S_MASK(pass,depth,png))
3200 #endif /* !USE_COMPILE_TIME_MASKS */
3202 /* Use the appropriate mask to copy the required bits. In some cases
3203 * the byte mask will be 0 or 0xff; optimize these cases. row_width is
3204 * the number of pixels, but the code copies bytes, so it is necessary
3205 * to special case the end.
3207 png_uint_32 pixels_per_byte
= 8 / pixel_depth
;
3210 # ifdef PNG_READ_PACKSWAP_SUPPORTED
3211 if ((png_ptr
->transformations
& PNG_PACKSWAP
) != 0)
3212 mask
= MASK(pass
, pixel_depth
, display
, 0);
3216 mask
= MASK(pass
, pixel_depth
, display
, 1);
3222 /* It doesn't matter in the following if png_uint_32 has more than
3223 * 32 bits because the high bits always match those in m<<24; it is,
3224 * however, essential to use OR here, not +, because of this.
3227 mask
= (m
>> 8) | (m
<< 24); /* rotate right to good compilers */
3230 if (m
!= 0) /* something to copy */
3233 *dp
= (png_byte
)((*dp
& ~m
) | (*sp
& m
));
3238 /* NOTE: this may overwrite the last byte with garbage if the image
3239 * is not an exact number of bytes wide; libpng has always done
3242 if (row_width
<= pixels_per_byte
)
3243 break; /* May need to restore part of the last byte */
3245 row_width
-= pixels_per_byte
;
3251 else /* pixel_depth >= 8 */
3253 unsigned int bytes_to_copy
, bytes_to_jump
;
3255 /* Validate the depth - it must be a multiple of 8 */
3256 if (pixel_depth
& 7)
3257 png_error(png_ptr
, "invalid user transform pixel depth");
3259 pixel_depth
>>= 3; /* now in bytes */
3260 row_width
*= pixel_depth
;
3262 /* Regardless of pass number the Adam 7 interlace always results in a
3263 * fixed number of pixels to copy then to skip. There may be a
3264 * different number of pixels to skip at the start though.
3267 unsigned int offset
= PNG_PASS_START_COL(pass
) * pixel_depth
;
3269 row_width
-= offset
;
3274 /* Work out the bytes to copy. */
3277 /* When doing the 'block' algorithm the pixel in the pass gets
3278 * replicated to adjacent pixels. This is why the even (0,2,4,6)
3279 * passes are skipped above - the entire expanded row is copied.
3281 bytes_to_copy
= (1<<((6-pass
)>>1)) * pixel_depth
;
3283 /* But don't allow this number to exceed the actual row width. */
3284 if (bytes_to_copy
> row_width
)
3285 bytes_to_copy
= (unsigned int)/*SAFE*/row_width
;
3288 else /* normal row; Adam7 only ever gives us one pixel to copy. */
3289 bytes_to_copy
= pixel_depth
;
3291 /* In Adam7 there is a constant offset between where the pixels go. */
3292 bytes_to_jump
= PNG_PASS_COL_OFFSET(pass
) * pixel_depth
;
3294 /* And simply copy these bytes. Some optimization is possible here,
3295 * depending on the value of 'bytes_to_copy'. Special case the low
3296 * byte counts, which we know to be frequent.
3298 * Notice that these cases all 'return' rather than 'break' - this
3299 * avoids an unnecessary test on whether to restore the last byte
3302 switch (bytes_to_copy
)
3309 if (row_width
<= bytes_to_jump
)
3312 dp
+= bytes_to_jump
;
3313 sp
+= bytes_to_jump
;
3314 row_width
-= bytes_to_jump
;
3318 /* There is a possibility of a partial copy at the end here; this
3319 * slows the code down somewhat.
3323 dp
[0] = sp
[0], dp
[1] = sp
[1];
3325 if (row_width
<= bytes_to_jump
)
3328 sp
+= bytes_to_jump
;
3329 dp
+= bytes_to_jump
;
3330 row_width
-= bytes_to_jump
;
3332 while (row_width
> 1);
3334 /* And there can only be one byte left at this point: */
3339 /* This can only be the RGB case, so each copy is exactly one
3340 * pixel and it is not necessary to check for a partial copy.
3344 dp
[0] = sp
[0], dp
[1] = sp
[1], dp
[2] = sp
[2];
3346 if (row_width
<= bytes_to_jump
)
3349 sp
+= bytes_to_jump
;
3350 dp
+= bytes_to_jump
;
3351 row_width
-= bytes_to_jump
;
3355 #if PNG_ALIGN_TYPE != PNG_ALIGN_NONE
3356 /* Check for double byte alignment and, if possible, use a
3357 * 16-bit copy. Don't attempt this for narrow images - ones that
3358 * are less than an interlace panel wide. Don't attempt it for
3359 * wide bytes_to_copy either - use the memcpy there.
3361 if (bytes_to_copy
< 16 /*else use memcpy*/ &&
3362 png_isaligned(dp
, png_uint_16
) &&
3363 png_isaligned(sp
, png_uint_16
) &&
3364 bytes_to_copy
% (sizeof (png_uint_16
)) == 0 &&
3365 bytes_to_jump
% (sizeof (png_uint_16
)) == 0)
3367 /* Everything is aligned for png_uint_16 copies, but try for
3368 * png_uint_32 first.
3370 if (png_isaligned(dp
, png_uint_32
) != 0 &&
3371 png_isaligned(sp
, png_uint_32
) != 0 &&
3372 bytes_to_copy
% (sizeof (png_uint_32
)) == 0 &&
3373 bytes_to_jump
% (sizeof (png_uint_32
)) == 0)
3375 png_uint_32p dp32
= png_aligncast(png_uint_32p
,dp
);
3376 png_const_uint_32p sp32
= png_aligncastconst(
3377 png_const_uint_32p
, sp
);
3378 size_t skip
= (bytes_to_jump
-bytes_to_copy
) /
3379 (sizeof (png_uint_32
));
3383 size_t c
= bytes_to_copy
;
3387 c
-= (sizeof (png_uint_32
));
3391 if (row_width
<= bytes_to_jump
)
3396 row_width
-= bytes_to_jump
;
3398 while (bytes_to_copy
<= row_width
);
3400 /* Get to here when the row_width truncates the final copy.
3401 * There will be 1-3 bytes left to copy, so don't try the
3402 * 16-bit loop below.
3404 dp
= (png_bytep
)dp32
;
3405 sp
= (png_const_bytep
)sp32
;
3408 while (--row_width
> 0);
3412 /* Else do it in 16-bit quantities, but only if the size is
3417 png_uint_16p dp16
= png_aligncast(png_uint_16p
, dp
);
3418 png_const_uint_16p sp16
= png_aligncastconst(
3419 png_const_uint_16p
, sp
);
3420 size_t skip
= (bytes_to_jump
-bytes_to_copy
) /
3421 (sizeof (png_uint_16
));
3425 size_t c
= bytes_to_copy
;
3429 c
-= (sizeof (png_uint_16
));
3433 if (row_width
<= bytes_to_jump
)
3438 row_width
-= bytes_to_jump
;
3440 while (bytes_to_copy
<= row_width
);
3442 /* End of row - 1 byte left, bytes_to_copy > row_width: */
3443 dp
= (png_bytep
)dp16
;
3444 sp
= (png_const_bytep
)sp16
;
3447 while (--row_width
> 0);
3451 #endif /* ALIGN_TYPE code */
3453 /* The true default - use a memcpy: */
3456 memcpy(dp
, sp
, bytes_to_copy
);
3458 if (row_width
<= bytes_to_jump
)
3461 sp
+= bytes_to_jump
;
3462 dp
+= bytes_to_jump
;
3463 row_width
-= bytes_to_jump
;
3464 if (bytes_to_copy
> row_width
)
3465 bytes_to_copy
= (unsigned int)/*SAFE*/row_width
;
3470 } /* pixel_depth >= 8 */
3472 /* Here if pixel_depth < 8 to check 'end_ptr' below. */
3475 #endif /* READ_INTERLACING */
3477 /* If here then the switch above wasn't used so just memcpy the whole row
3478 * from the temporary row buffer (notice that this overwrites the end of the
3479 * destination row if it is a partial byte.)
3481 memcpy(dp
, sp
, PNG_ROWBYTES(pixel_depth
, row_width
));
3483 /* Restore the overwritten bits from the last byte if necessary. */
3484 if (end_ptr
!= NULL
)
3485 *end_ptr
= (png_byte
)((end_byte
& end_mask
) | (*end_ptr
& ~end_mask
));
3488 #ifdef PNG_READ_INTERLACING_SUPPORTED
3490 png_do_read_interlace(png_row_infop row_info
, png_bytep row
, int pass
,
3491 png_uint_32 transformations
/* Because these may affect the byte layout */)
3493 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
3494 /* Offset to next interlace block */
3495 static PNG_CONST
int png_pass_inc
[7] = {8, 8, 4, 4, 2, 2, 1};
3497 png_debug(1, "in png_do_read_interlace");
3498 if (row
!= NULL
&& row_info
!= NULL
)
3500 png_uint_32 final_width
;
3502 final_width
= row_info
->width
* png_pass_inc
[pass
];
3504 switch (row_info
->pixel_depth
)
3508 png_bytep sp
= row
+ (png_size_t
)((row_info
->width
- 1) >> 3);
3509 png_bytep dp
= row
+ (png_size_t
)((final_width
- 1) >> 3);
3511 int s_start
, s_end
, s_inc
;
3512 int jstop
= png_pass_inc
[pass
];
3517 #ifdef PNG_READ_PACKSWAP_SUPPORTED
3518 if ((transformations
& PNG_PACKSWAP
) != 0)
3520 sshift
= (int)((row_info
->width
+ 7) & 0x07);
3521 dshift
= (int)((final_width
+ 7) & 0x07);
3530 sshift
= 7 - (int)((row_info
->width
+ 7) & 0x07);
3531 dshift
= 7 - (int)((final_width
+ 7) & 0x07);
3537 for (i
= 0; i
< row_info
->width
; i
++)
3539 v
= (png_byte
)((*sp
>> sshift
) & 0x01);
3540 for (j
= 0; j
< jstop
; j
++)
3542 unsigned int tmp
= *dp
& (0x7f7f >> (7 - dshift
));
3544 *dp
= (png_byte
)(tmp
& 0xff);
3546 if (dshift
== s_end
)
3556 if (sshift
== s_end
)
3570 png_bytep sp
= row
+ (png_uint_32
)((row_info
->width
- 1) >> 2);
3571 png_bytep dp
= row
+ (png_uint_32
)((final_width
- 1) >> 2);
3573 int s_start
, s_end
, s_inc
;
3574 int jstop
= png_pass_inc
[pass
];
3577 #ifdef PNG_READ_PACKSWAP_SUPPORTED
3578 if ((transformations
& PNG_PACKSWAP
) != 0)
3580 sshift
= (int)(((row_info
->width
+ 3) & 0x03) << 1);
3581 dshift
= (int)(((final_width
+ 3) & 0x03) << 1);
3590 sshift
= (int)((3 - ((row_info
->width
+ 3) & 0x03)) << 1);
3591 dshift
= (int)((3 - ((final_width
+ 3) & 0x03)) << 1);
3597 for (i
= 0; i
< row_info
->width
; i
++)
3602 v
= (png_byte
)((*sp
>> sshift
) & 0x03);
3603 for (j
= 0; j
< jstop
; j
++)
3605 unsigned int tmp
= *dp
& (0x3f3f >> (6 - dshift
));
3607 *dp
= (png_byte
)(tmp
& 0xff);
3609 if (dshift
== s_end
)
3619 if (sshift
== s_end
)
3633 png_bytep sp
= row
+ (png_size_t
)((row_info
->width
- 1) >> 1);
3634 png_bytep dp
= row
+ (png_size_t
)((final_width
- 1) >> 1);
3636 int s_start
, s_end
, s_inc
;
3638 int jstop
= png_pass_inc
[pass
];
3640 #ifdef PNG_READ_PACKSWAP_SUPPORTED
3641 if ((transformations
& PNG_PACKSWAP
) != 0)
3643 sshift
= (int)(((row_info
->width
+ 1) & 0x01) << 2);
3644 dshift
= (int)(((final_width
+ 1) & 0x01) << 2);
3653 sshift
= (int)((1 - ((row_info
->width
+ 1) & 0x01)) << 2);
3654 dshift
= (int)((1 - ((final_width
+ 1) & 0x01)) << 2);
3660 for (i
= 0; i
< row_info
->width
; i
++)
3662 png_byte v
= (png_byte
)((*sp
>> sshift
) & 0x0f);
3665 for (j
= 0; j
< jstop
; j
++)
3667 unsigned int tmp
= *dp
& (0xf0f >> (4 - dshift
));
3669 *dp
= (png_byte
)(tmp
& 0xff);
3671 if (dshift
== s_end
)
3681 if (sshift
== s_end
)
3695 png_size_t pixel_bytes
= (row_info
->pixel_depth
>> 3);
3697 png_bytep sp
= row
+ (png_size_t
)(row_info
->width
- 1)
3700 png_bytep dp
= row
+ (png_size_t
)(final_width
- 1) * pixel_bytes
;
3702 int jstop
= png_pass_inc
[pass
];
3705 for (i
= 0; i
< row_info
->width
; i
++)
3707 png_byte v
[8]; /* SAFE; pixel_depth does not exceed 64 */
3710 memcpy(v
, sp
, pixel_bytes
);
3712 for (j
= 0; j
< jstop
; j
++)
3714 memcpy(dp
, v
, pixel_bytes
);
3724 row_info
->width
= final_width
;
3725 row_info
->rowbytes
= PNG_ROWBYTES(row_info
->pixel_depth
, final_width
);
3727 #ifndef PNG_READ_PACKSWAP_SUPPORTED
3728 PNG_UNUSED(transformations
) /* Silence compiler warning */
3731 #endif /* READ_INTERLACING */
3734 png_read_filter_row_sub(png_row_infop row_info
, png_bytep row
,
3735 png_const_bytep prev_row
)
3738 png_size_t istop
= row_info
->rowbytes
;
3739 unsigned int bpp
= (row_info
->pixel_depth
+ 7) >> 3;
3740 png_bytep rp
= row
+ bpp
;
3742 PNG_UNUSED(prev_row
)
3744 for (i
= bpp
; i
< istop
; i
++)
3746 *rp
= (png_byte
)(((int)(*rp
) + (int)(*(rp
-bpp
))) & 0xff);
3752 png_read_filter_row_up(png_row_infop row_info
, png_bytep row
,
3753 png_const_bytep prev_row
)
3756 png_size_t istop
= row_info
->rowbytes
;
3758 png_const_bytep pp
= prev_row
;
3760 for (i
= 0; i
< istop
; i
++)
3762 *rp
= (png_byte
)(((int)(*rp
) + (int)(*pp
++)) & 0xff);
3768 png_read_filter_row_avg(png_row_infop row_info
, png_bytep row
,
3769 png_const_bytep prev_row
)
3773 png_const_bytep pp
= prev_row
;
3774 unsigned int bpp
= (row_info
->pixel_depth
+ 7) >> 3;
3775 png_size_t istop
= row_info
->rowbytes
- bpp
;
3777 for (i
= 0; i
< bpp
; i
++)
3779 *rp
= (png_byte
)(((int)(*rp
) +
3780 ((int)(*pp
++) / 2 )) & 0xff);
3785 for (i
= 0; i
< istop
; i
++)
3787 *rp
= (png_byte
)(((int)(*rp
) +
3788 (int)(*pp
++ + *(rp
-bpp
)) / 2 ) & 0xff);
3795 png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info
, png_bytep row
,
3796 png_const_bytep prev_row
)
3798 png_bytep rp_end
= row
+ row_info
->rowbytes
;
3801 /* First pixel/byte */
3804 *row
++ = (png_byte
)a
;
3807 while (row
< rp_end
)
3809 int b
, pa
, pb
, pc
, p
;
3811 a
&= 0xff; /* From previous iteration or start */
3822 pa
= p
< 0 ? -p
: p
;
3823 pb
= pc
< 0 ? -pc
: pc
;
3824 pc
= (p
+ pc
) < 0 ? -(p
+ pc
) : p
+ pc
;
3827 /* Find the best predictor, the least of pa, pb, pc favoring the earlier
3828 * ones in the case of a tie.
3830 if (pb
< pa
) pa
= pb
, a
= b
;
3833 /* Calculate the current pixel in a, and move the previous row pixel to c
3834 * for the next time round the loop
3838 *row
++ = (png_byte
)a
;
3843 png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info
, png_bytep row
,
3844 png_const_bytep prev_row
)
3846 int bpp
= (row_info
->pixel_depth
+ 7) >> 3;
3847 png_bytep rp_end
= row
+ bpp
;
3849 /* Process the first pixel in the row completely (this is the same as 'up'
3850 * because there is only one candidate predictor for the first row).
3852 while (row
< rp_end
)
3854 int a
= *row
+ *prev_row
++;
3855 *row
++ = (png_byte
)a
;
3859 rp_end
+= row_info
->rowbytes
- bpp
;
3861 while (row
< rp_end
)
3863 int a
, b
, c
, pa
, pb
, pc
, p
;
3865 c
= *(prev_row
- bpp
);
3877 pa
= p
< 0 ? -p
: p
;
3878 pb
= pc
< 0 ? -pc
: pc
;
3879 pc
= (p
+ pc
) < 0 ? -(p
+ pc
) : p
+ pc
;
3882 if (pb
< pa
) pa
= pb
, a
= b
;
3886 *row
++ = (png_byte
)a
;
3891 png_init_filter_functions(png_structrp pp
)
3892 /* This function is called once for every PNG image (except for PNG images
3893 * that only use PNG_FILTER_VALUE_NONE for all rows) to set the
3894 * implementations required to reverse the filtering of PNG rows. Reversing
3895 * the filter is the first transformation performed on the row data. It is
3896 * performed in place, therefore an implementation can be selected based on
3897 * the image pixel format. If the implementation depends on image width then
3898 * take care to ensure that it works correctly if the image is interlaced -
3899 * interlacing causes the actual row width to vary.
3902 unsigned int bpp
= (pp
->pixel_depth
+ 7) >> 3;
3904 pp
->read_filter
[PNG_FILTER_VALUE_SUB
-1] = png_read_filter_row_sub
;
3905 pp
->read_filter
[PNG_FILTER_VALUE_UP
-1] = png_read_filter_row_up
;
3906 pp
->read_filter
[PNG_FILTER_VALUE_AVG
-1] = png_read_filter_row_avg
;
3908 pp
->read_filter
[PNG_FILTER_VALUE_PAETH
-1] =
3909 png_read_filter_row_paeth_1byte_pixel
;
3911 pp
->read_filter
[PNG_FILTER_VALUE_PAETH
-1] =
3912 png_read_filter_row_paeth_multibyte_pixel
;
3914 #ifdef PNG_FILTER_OPTIMIZATIONS
3915 /* To use this define PNG_FILTER_OPTIMIZATIONS as the name of a function to
3916 * call to install hardware optimizations for the above functions; simply
3917 * replace whatever elements of the pp->read_filter[] array with a hardware
3918 * specific (or, for that matter, generic) optimization.
3920 * To see an example of this examine what configure.ac does when
3921 * --enable-arm-neon is specified on the command line.
3923 PNG_FILTER_OPTIMIZATIONS(pp
, bpp
);
3928 png_read_filter_row(png_structrp pp
, png_row_infop row_info
, png_bytep row
,
3929 png_const_bytep prev_row
, int filter
)
3931 /* OPTIMIZATION: DO NOT MODIFY THIS FUNCTION, instead #define
3932 * PNG_FILTER_OPTIMIZATIONS to a function that overrides the generic
3933 * implementations. See png_init_filter_functions above.
3935 if (filter
> PNG_FILTER_VALUE_NONE
&& filter
< PNG_FILTER_VALUE_LAST
)
3937 if (pp
->read_filter
[0] == NULL
)
3938 png_init_filter_functions(pp
);
3940 pp
->read_filter
[filter
-1](row_info
, row
, prev_row
);
3944 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
3946 png_read_IDAT_data(png_structrp png_ptr
, png_bytep output
,
3947 png_alloc_size_t avail_out
)
3949 /* Loop reading IDATs and decompressing the result into output[avail_out] */
3950 png_ptr
->zstream
.next_out
= output
;
3951 png_ptr
->zstream
.avail_out
= 0; /* safety: set below */
3959 png_byte tmpbuf
[PNG_INFLATE_BUF_SIZE
];
3961 if (png_ptr
->zstream
.avail_in
== 0)
3966 while (png_ptr
->idat_size
== 0)
3968 png_crc_finish(png_ptr
, 0);
3970 png_ptr
->idat_size
= png_read_chunk_header(png_ptr
);
3971 /* This is an error even in the 'check' case because the code just
3972 * consumed a non-IDAT header.
3974 if (png_ptr
->chunk_name
!= png_IDAT
)
3975 png_error(png_ptr
, "Not enough image data");
3978 avail_in
= png_ptr
->IDAT_read_size
;
3980 if (avail_in
> png_ptr
->idat_size
)
3981 avail_in
= (uInt
)png_ptr
->idat_size
;
3983 /* A PNG with a gradually increasing IDAT size will defeat this attempt
3984 * to minimize memory usage by causing lots of re-allocs, but
3985 * realistically doing IDAT_read_size re-allocs is not likely to be a
3988 buffer
= png_read_buffer(png_ptr
, avail_in
, 0/*error*/);
3990 png_crc_read(png_ptr
, buffer
, avail_in
);
3991 png_ptr
->idat_size
-= avail_in
;
3993 png_ptr
->zstream
.next_in
= buffer
;
3994 png_ptr
->zstream
.avail_in
= avail_in
;
3997 /* And set up the output side. */
3998 if (output
!= NULL
) /* standard read */
4000 uInt out
= ZLIB_IO_MAX
;
4002 if (out
> avail_out
)
4003 out
= (uInt
)avail_out
;
4006 png_ptr
->zstream
.avail_out
= out
;
4009 else /* after last row, checking for end */
4011 png_ptr
->zstream
.next_out
= tmpbuf
;
4012 png_ptr
->zstream
.avail_out
= (sizeof tmpbuf
);
4015 /* Use NO_FLUSH; this gives zlib the maximum opportunity to optimize the
4016 * process. If the LZ stream is truncated the sequential reader will
4017 * terminally damage the stream, above, by reading the chunk header of the
4018 * following chunk (it then exits with png_error).
4020 * TODO: deal more elegantly with truncated IDAT lists.
4022 ret
= inflate(&png_ptr
->zstream
, Z_NO_FLUSH
);
4024 /* Take the unconsumed output back. */
4026 avail_out
+= png_ptr
->zstream
.avail_out
;
4028 else /* avail_out counts the extra bytes */
4029 avail_out
+= (sizeof tmpbuf
) - png_ptr
->zstream
.avail_out
;
4031 png_ptr
->zstream
.avail_out
= 0;
4033 if (ret
== Z_STREAM_END
)
4035 /* Do this for safety; we won't read any more into this row. */
4036 png_ptr
->zstream
.next_out
= NULL
;
4038 png_ptr
->mode
|= PNG_AFTER_IDAT
;
4039 png_ptr
->flags
|= PNG_FLAG_ZSTREAM_ENDED
;
4041 if (png_ptr
->zstream
.avail_in
> 0 || png_ptr
->idat_size
> 0)
4042 png_chunk_benign_error(png_ptr
, "Extra compressed data");
4048 png_zstream_error(png_ptr
, ret
);
4051 png_chunk_error(png_ptr
, png_ptr
->zstream
.msg
);
4055 png_chunk_benign_error(png_ptr
, png_ptr
->zstream
.msg
);
4059 } while (avail_out
> 0);
4063 /* The stream ended before the image; this is the same as too few IDATs so
4064 * should be handled the same way.
4067 png_error(png_ptr
, "Not enough image data");
4069 else /* the deflate stream contained extra data */
4070 png_chunk_benign_error(png_ptr
, "Too much image data");
4075 png_read_finish_IDAT(png_structrp png_ptr
)
4077 /* We don't need any more data and the stream should have ended, however the
4078 * LZ end code may actually not have been processed. In this case we must
4079 * read it otherwise stray unread IDAT data or, more likely, an IDAT chunk
4080 * may still remain to be consumed.
4082 if ((png_ptr
->flags
& PNG_FLAG_ZSTREAM_ENDED
) == 0)
4084 /* The NULL causes png_read_IDAT_data to swallow any remaining bytes in
4085 * the compressed stream, but the stream may be damaged too, so even after
4086 * this call we may need to terminate the zstream ownership.
4088 png_read_IDAT_data(png_ptr
, NULL
, 0);
4089 png_ptr
->zstream
.next_out
= NULL
; /* safety */
4091 /* Now clear everything out for safety; the following may not have been
4094 if ((png_ptr
->flags
& PNG_FLAG_ZSTREAM_ENDED
) == 0)
4096 png_ptr
->mode
|= PNG_AFTER_IDAT
;
4097 png_ptr
->flags
|= PNG_FLAG_ZSTREAM_ENDED
;
4101 /* If the zstream has not been released do it now *and* terminate the reading
4102 * of the final IDAT chunk.
4104 if (png_ptr
->zowner
== png_IDAT
)
4106 /* Always do this; the pointers otherwise point into the read buffer. */
4107 png_ptr
->zstream
.next_in
= NULL
;
4108 png_ptr
->zstream
.avail_in
= 0;
4110 /* Now we no longer own the zstream. */
4111 png_ptr
->zowner
= 0;
4113 /* The slightly weird semantics of the sequential IDAT reading is that we
4114 * are always in or at the end of an IDAT chunk, so we always need to do a
4115 * crc_finish here. If idat_size is non-zero we also need to read the
4116 * spurious bytes at the end of the chunk now.
4118 (void)png_crc_finish(png_ptr
, png_ptr
->idat_size
);
4123 png_read_finish_row(png_structrp png_ptr
)
4125 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
4127 /* Start of interlace block */
4128 static PNG_CONST png_byte png_pass_start
[7] = {0, 4, 0, 2, 0, 1, 0};
4130 /* Offset to next interlace block */
4131 static PNG_CONST png_byte png_pass_inc
[7] = {8, 8, 4, 4, 2, 2, 1};
4133 /* Start of interlace block in the y direction */
4134 static PNG_CONST png_byte png_pass_ystart
[7] = {0, 0, 4, 0, 2, 0, 1};
4136 /* Offset to next interlace block in the y direction */
4137 static PNG_CONST png_byte png_pass_yinc
[7] = {8, 8, 8, 4, 4, 2, 2};
4139 png_debug(1, "in png_read_finish_row");
4140 png_ptr
->row_number
++;
4141 if (png_ptr
->row_number
< png_ptr
->num_rows
)
4144 if (png_ptr
->interlaced
!= 0)
4146 png_ptr
->row_number
= 0;
4148 /* TO DO: don't do this if prev_row isn't needed (requires
4149 * read-ahead of the next row's filter byte.
4151 memset(png_ptr
->prev_row
, 0, png_ptr
->rowbytes
+ 1);
4157 if (png_ptr
->pass
>= 7)
4160 png_ptr
->iwidth
= (png_ptr
->width
+
4161 png_pass_inc
[png_ptr
->pass
] - 1 -
4162 png_pass_start
[png_ptr
->pass
]) /
4163 png_pass_inc
[png_ptr
->pass
];
4165 if ((png_ptr
->transformations
& PNG_INTERLACE
) == 0)
4167 png_ptr
->num_rows
= (png_ptr
->height
+
4168 png_pass_yinc
[png_ptr
->pass
] - 1 -
4169 png_pass_ystart
[png_ptr
->pass
]) /
4170 png_pass_yinc
[png_ptr
->pass
];
4173 else /* if (png_ptr->transformations & PNG_INTERLACE) */
4174 break; /* libpng deinterlacing sees every row */
4176 } while (png_ptr
->num_rows
== 0 || png_ptr
->iwidth
== 0);
4178 if (png_ptr
->pass
< 7)
4182 /* Here after at the end of the last row of the last pass. */
4183 png_read_finish_IDAT(png_ptr
);
4185 #endif /* SEQUENTIAL_READ */
4188 png_read_start_row(png_structrp png_ptr
)
4190 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
4192 /* Start of interlace block */
4193 static PNG_CONST png_byte png_pass_start
[7] = {0, 4, 0, 2, 0, 1, 0};
4195 /* Offset to next interlace block */
4196 static PNG_CONST png_byte png_pass_inc
[7] = {8, 8, 4, 4, 2, 2, 1};
4198 /* Start of interlace block in the y direction */
4199 static PNG_CONST png_byte png_pass_ystart
[7] = {0, 0, 4, 0, 2, 0, 1};
4201 /* Offset to next interlace block in the y direction */
4202 static PNG_CONST png_byte png_pass_yinc
[7] = {8, 8, 8, 4, 4, 2, 2};
4204 int max_pixel_depth
;
4205 png_size_t row_bytes
;
4207 png_debug(1, "in png_read_start_row");
4209 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
4210 png_init_read_transformations(png_ptr
);
4212 if (png_ptr
->interlaced
!= 0)
4214 if ((png_ptr
->transformations
& PNG_INTERLACE
) == 0)
4215 png_ptr
->num_rows
= (png_ptr
->height
+ png_pass_yinc
[0] - 1 -
4216 png_pass_ystart
[0]) / png_pass_yinc
[0];
4219 png_ptr
->num_rows
= png_ptr
->height
;
4221 png_ptr
->iwidth
= (png_ptr
->width
+
4222 png_pass_inc
[png_ptr
->pass
] - 1 -
4223 png_pass_start
[png_ptr
->pass
]) /
4224 png_pass_inc
[png_ptr
->pass
];
4229 png_ptr
->num_rows
= png_ptr
->height
;
4230 png_ptr
->iwidth
= png_ptr
->width
;
4233 max_pixel_depth
= png_ptr
->pixel_depth
;
4235 /* WARNING: * png_read_transform_info (pngrtran.c) performs a simpler set of
4236 * calculations to calculate the final pixel depth, then
4237 * png_do_read_transforms actually does the transforms. This means that the
4238 * code which effectively calculates this value is actually repeated in three
4239 * separate places. They must all match. Innocent changes to the order of
4240 * transformations can and will break libpng in a way that causes memory
4245 #ifdef PNG_READ_PACK_SUPPORTED
4246 if ((png_ptr
->transformations
& PNG_PACK
) != 0 && png_ptr
->bit_depth
< 8)
4247 max_pixel_depth
= 8;
4250 #ifdef PNG_READ_EXPAND_SUPPORTED
4251 if ((png_ptr
->transformations
& PNG_EXPAND
) != 0)
4253 if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
4255 if (png_ptr
->num_trans
!= 0)
4256 max_pixel_depth
= 32;
4259 max_pixel_depth
= 24;
4262 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_GRAY
)
4264 if (max_pixel_depth
< 8)
4265 max_pixel_depth
= 8;
4267 if (png_ptr
->num_trans
!= 0)
4268 max_pixel_depth
*= 2;
4271 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_RGB
)
4273 if (png_ptr
->num_trans
!= 0)
4275 max_pixel_depth
*= 4;
4276 max_pixel_depth
/= 3;
4282 #ifdef PNG_READ_EXPAND_16_SUPPORTED
4283 if ((png_ptr
->transformations
& PNG_EXPAND_16
) != 0)
4285 # ifdef PNG_READ_EXPAND_SUPPORTED
4286 /* In fact it is an error if it isn't supported, but checking is
4289 if ((png_ptr
->transformations
& PNG_EXPAND
) != 0)
4291 if (png_ptr
->bit_depth
< 16)
4292 max_pixel_depth
*= 2;
4296 png_ptr
->transformations
&= ~PNG_EXPAND_16
;
4300 #ifdef PNG_READ_FILLER_SUPPORTED
4301 if ((png_ptr
->transformations
& (PNG_FILLER
)) != 0)
4303 if (png_ptr
->color_type
== PNG_COLOR_TYPE_GRAY
)
4305 if (max_pixel_depth
<= 8)
4306 max_pixel_depth
= 16;
4309 max_pixel_depth
= 32;
4312 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_RGB
||
4313 png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
4315 if (max_pixel_depth
<= 32)
4316 max_pixel_depth
= 32;
4319 max_pixel_depth
= 64;
4324 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
4325 if ((png_ptr
->transformations
& PNG_GRAY_TO_RGB
) != 0)
4328 #ifdef PNG_READ_EXPAND_SUPPORTED
4329 (png_ptr
->num_trans
!= 0 &&
4330 (png_ptr
->transformations
& PNG_EXPAND
) != 0) ||
4332 #ifdef PNG_READ_FILLER_SUPPORTED
4333 (png_ptr
->transformations
& (PNG_FILLER
)) != 0 ||
4335 png_ptr
->color_type
== PNG_COLOR_TYPE_GRAY_ALPHA
)
4337 if (max_pixel_depth
<= 16)
4338 max_pixel_depth
= 32;
4341 max_pixel_depth
= 64;
4346 if (max_pixel_depth
<= 8)
4348 if (png_ptr
->color_type
== PNG_COLOR_TYPE_RGB_ALPHA
)
4349 max_pixel_depth
= 32;
4352 max_pixel_depth
= 24;
4355 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_RGB_ALPHA
)
4356 max_pixel_depth
= 64;
4359 max_pixel_depth
= 48;
4364 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) && \
4365 defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
4366 if ((png_ptr
->transformations
& PNG_USER_TRANSFORM
) != 0)
4368 int user_pixel_depth
= png_ptr
->user_transform_depth
*
4369 png_ptr
->user_transform_channels
;
4371 if (user_pixel_depth
> max_pixel_depth
)
4372 max_pixel_depth
= user_pixel_depth
;
4376 /* This value is stored in png_struct and double checked in the row read
4379 png_ptr
->maximum_pixel_depth
= (png_byte
)max_pixel_depth
;
4380 png_ptr
->transformed_pixel_depth
= 0; /* calculated on demand */
4382 /* Align the width on the next larger 8 pixels. Mainly used
4385 row_bytes
= ((png_ptr
->width
+ 7) & ~((png_uint_32
)7));
4386 /* Calculate the maximum bytes needed, adding a byte and a pixel
4389 row_bytes
= PNG_ROWBYTES(max_pixel_depth
, row_bytes
) +
4390 1 + ((max_pixel_depth
+ 7) >> 3);
4392 #ifdef PNG_MAX_MALLOC_64K
4393 if (row_bytes
> (png_uint_32
)65536L)
4394 png_error(png_ptr
, "This image requires a row greater than 64KB");
4397 if (row_bytes
+ 48 > png_ptr
->old_big_row_buf_size
)
4399 png_free(png_ptr
, png_ptr
->big_row_buf
);
4400 png_free(png_ptr
, png_ptr
->big_prev_row
);
4402 if (png_ptr
->interlaced
!= 0)
4403 png_ptr
->big_row_buf
= (png_bytep
)png_calloc(png_ptr
,
4407 png_ptr
->big_row_buf
= (png_bytep
)png_malloc(png_ptr
, row_bytes
+ 48);
4409 png_ptr
->big_prev_row
= (png_bytep
)png_malloc(png_ptr
, row_bytes
+ 48);
4411 #ifdef PNG_ALIGNED_MEMORY_SUPPORTED
4412 /* Use 16-byte aligned memory for row_buf with at least 16 bytes
4413 * of padding before and after row_buf; treat prev_row similarly.
4414 * NOTE: the alignment is to the start of the pixels, one beyond the start
4415 * of the buffer, because of the filter byte. Prior to libpng 1.5.6 this
4416 * was incorrect; the filter byte was aligned, which had the exact
4417 * opposite effect of that intended.
4420 png_bytep temp
= png_ptr
->big_row_buf
+ 32;
4421 int extra
= (int)((temp
- (png_bytep
)0) & 0x0f);
4422 png_ptr
->row_buf
= temp
- extra
- 1/*filter byte*/;
4424 temp
= png_ptr
->big_prev_row
+ 32;
4425 extra
= (int)((temp
- (png_bytep
)0) & 0x0f);
4426 png_ptr
->prev_row
= temp
- extra
- 1/*filter byte*/;
4430 /* Use 31 bytes of padding before and 17 bytes after row_buf. */
4431 png_ptr
->row_buf
= png_ptr
->big_row_buf
+ 31;
4432 png_ptr
->prev_row
= png_ptr
->big_prev_row
+ 31;
4434 png_ptr
->old_big_row_buf_size
= row_bytes
+ 48;
4437 #ifdef PNG_MAX_MALLOC_64K
4438 if (png_ptr
->rowbytes
> 65535)
4439 png_error(png_ptr
, "This image requires a row greater than 64KB");
4442 if (png_ptr
->rowbytes
> (PNG_SIZE_MAX
- 1))
4443 png_error(png_ptr
, "Row has too many bytes to allocate in memory");
4445 memset(png_ptr
->prev_row
, 0, png_ptr
->rowbytes
+ 1);
4447 png_debug1(3, "width = %u,", png_ptr
->width
);
4448 png_debug1(3, "height = %u,", png_ptr
->height
);
4449 png_debug1(3, "iwidth = %u,", png_ptr
->iwidth
);
4450 png_debug1(3, "num_rows = %u,", png_ptr
->num_rows
);
4451 png_debug1(3, "rowbytes = %lu,", (unsigned long)png_ptr
->rowbytes
);
4452 png_debug1(3, "irowbytes = %lu",
4453 (unsigned long)PNG_ROWBYTES(png_ptr
->pixel_depth
, png_ptr
->iwidth
) + 1);
4455 /* The sequential reader needs a buffer for IDAT, but the progressive reader
4456 * does not, so free the read buffer now regardless; the sequential reader
4457 * reallocates it on demand.
4459 if (png_ptr
->read_buffer
!= 0)
4461 png_bytep buffer
= png_ptr
->read_buffer
;
4463 png_ptr
->read_buffer_size
= 0;
4464 png_ptr
->read_buffer
= NULL
;
4465 png_free(png_ptr
, buffer
);
4468 /* Finally claim the zstream for the inflate of the IDAT data, use the bits
4469 * value from the stream (note that this will result in a fatal error if the
4470 * IDAT stream has a bogus deflate header window_bits value, but this should
4471 * not be happening any longer!)
4473 if (png_inflate_claim(png_ptr
, png_IDAT
) != Z_OK
)
4474 png_error(png_ptr
, png_ptr
->zstream
.msg
);
4476 png_ptr
->flags
|= PNG_FLAG_ROW_INIT
;