2 /* pngrutil.c - utilities to read a PNG file
4 * Last changed in libpng 1.6.20 [December 3, 2014]
5 * Copyright (c) 1998-2002,2004,2006-2015 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 if ((uval
& 0x80000000) == 0) /* no overflow */
93 return -(png_int_32
)uval
;
94 /* The following has to be safe; this function only gets called on PNG data
95 * and if we get here that data is invalid. 0 is the most safe value and
96 * if not then an attacker would surely just generate a PNG with 0 instead.
101 /* Grab an unsigned 16-bit integer from a buffer in big-endian format. */
103 png_get_uint_16
)(png_const_bytep buf
)
105 /* ANSI-C requires an int value to accomodate at least 16 bits so this
106 * works and allows the compiler not to worry about possible narrowing
107 * on 32-bit systems. (Pre-ANSI systems did not make integers smaller
108 * than 16 bits either.)
111 ((unsigned int)(*buf
) << 8) +
112 ((unsigned int)(*(buf
+ 1)));
114 return (png_uint_16
)val
;
117 #endif /* READ_INT_FUNCTIONS */
119 /* Read and check the PNG file signature */
121 png_read_sig(png_structrp png_ptr
, png_inforp info_ptr
)
123 png_size_t num_checked
, num_to_check
;
125 /* Exit if the user application does not expect a signature. */
126 if (png_ptr
->sig_bytes
>= 8)
129 num_checked
= png_ptr
->sig_bytes
;
130 num_to_check
= 8 - num_checked
;
132 #ifdef PNG_IO_STATE_SUPPORTED
133 png_ptr
->io_state
= PNG_IO_READING
| PNG_IO_SIGNATURE
;
136 /* The signature must be serialized in a single I/O call. */
137 png_read_data(png_ptr
, &(info_ptr
->signature
[num_checked
]), num_to_check
);
138 png_ptr
->sig_bytes
= 8;
140 if (png_sig_cmp(info_ptr
->signature
, num_checked
, num_to_check
) != 0)
142 if (num_checked
< 4 &&
143 png_sig_cmp(info_ptr
->signature
, num_checked
, num_to_check
- 4))
144 png_error(png_ptr
, "Not a PNG file");
146 png_error(png_ptr
, "PNG file corrupted by ASCII conversion");
149 png_ptr
->mode
|= PNG_HAVE_PNG_SIGNATURE
;
152 /* Read the chunk header (length + type name).
153 * Put the type name into png_ptr->chunk_name, and return the length.
155 png_uint_32
/* PRIVATE */
156 png_read_chunk_header(png_structrp png_ptr
)
161 #ifdef PNG_IO_STATE_SUPPORTED
162 png_ptr
->io_state
= PNG_IO_READING
| PNG_IO_CHUNK_HDR
;
165 /* Read the length and the chunk name.
166 * This must be performed in a single I/O call.
168 png_read_data(png_ptr
, buf
, 8);
169 length
= png_get_uint_31(png_ptr
, buf
);
171 /* Put the chunk name into png_ptr->chunk_name. */
172 png_ptr
->chunk_name
= PNG_CHUNK_FROM_STRING(buf
+4);
174 png_debug2(0, "Reading %lx chunk, length = %lu",
175 (unsigned long)png_ptr
->chunk_name
, (unsigned long)length
);
177 /* Reset the crc and run it over the chunk name. */
178 png_reset_crc(png_ptr
);
179 png_calculate_crc(png_ptr
, buf
+ 4, 4);
181 /* Check to see if chunk name is valid. */
182 png_check_chunk_name(png_ptr
, png_ptr
->chunk_name
);
184 #ifdef PNG_IO_STATE_SUPPORTED
185 png_ptr
->io_state
= PNG_IO_READING
| PNG_IO_CHUNK_DATA
;
191 /* Read data, and (optionally) run it through the CRC. */
193 png_crc_read(png_structrp png_ptr
, png_bytep buf
, png_uint_32 length
)
198 png_read_data(png_ptr
, buf
, length
);
199 png_calculate_crc(png_ptr
, buf
, length
);
202 /* Optionally skip data and then check the CRC. Depending on whether we
203 * are reading an ancillary or critical chunk, and how the program has set
204 * things up, we may calculate the CRC on the data and print a message.
205 * Returns '1' if there was a CRC error, '0' otherwise.
208 png_crc_finish(png_structrp png_ptr
, png_uint_32 skip
)
210 /* The size of the local buffer for inflate is a good guess as to a
211 * reasonable size to use for buffering reads from the application.
216 png_byte tmpbuf
[PNG_INFLATE_BUF_SIZE
];
218 len
= (sizeof tmpbuf
);
223 png_crc_read(png_ptr
, tmpbuf
, len
);
226 if (png_crc_error(png_ptr
) != 0)
228 if (PNG_CHUNK_ANCILLARY(png_ptr
->chunk_name
) != 0 ?
229 (png_ptr
->flags
& PNG_FLAG_CRC_ANCILLARY_NOWARN
) == 0 :
230 (png_ptr
->flags
& PNG_FLAG_CRC_CRITICAL_USE
) != 0)
232 png_chunk_warning(png_ptr
, "CRC error");
236 png_chunk_error(png_ptr
, "CRC error");
244 /* Compare the CRC stored in the PNG file with that calculated by libpng from
245 * the data it has read thus far.
248 png_crc_error(png_structrp png_ptr
)
250 png_byte crc_bytes
[4];
254 if (PNG_CHUNK_ANCILLARY(png_ptr
->chunk_name
) != 0)
256 if ((png_ptr
->flags
& PNG_FLAG_CRC_ANCILLARY_MASK
) ==
257 (PNG_FLAG_CRC_ANCILLARY_USE
| PNG_FLAG_CRC_ANCILLARY_NOWARN
))
263 if ((png_ptr
->flags
& PNG_FLAG_CRC_CRITICAL_IGNORE
) != 0)
267 #ifdef PNG_IO_STATE_SUPPORTED
268 png_ptr
->io_state
= PNG_IO_READING
| PNG_IO_CHUNK_CRC
;
271 /* The chunk CRC must be serialized in a single I/O call. */
272 png_read_data(png_ptr
, crc_bytes
, 4);
276 crc
= png_get_uint_32(crc_bytes
);
277 return ((int)(crc
!= png_ptr
->crc
));
284 #if defined(PNG_READ_iCCP_SUPPORTED) || defined(PNG_READ_iTXt_SUPPORTED) ||\
285 defined(PNG_READ_pCAL_SUPPORTED) || defined(PNG_READ_sCAL_SUPPORTED) ||\
286 defined(PNG_READ_sPLT_SUPPORTED) || defined(PNG_READ_tEXt_SUPPORTED) ||\
287 defined(PNG_READ_zTXt_SUPPORTED) || defined(PNG_SEQUENTIAL_READ_SUPPORTED)
288 /* Manage the read buffer; this simply reallocates the buffer if it is not small
289 * enough (or if it is not allocated). The routine returns a pointer to the
290 * buffer; if an error occurs and 'warn' is set the routine returns NULL, else
291 * it will call png_error (via png_malloc) on failure. (warn == 2 means
295 png_read_buffer(png_structrp png_ptr
, png_alloc_size_t new_size
, int warn
)
297 png_bytep buffer
= png_ptr
->read_buffer
;
299 if (buffer
!= NULL
&& new_size
> png_ptr
->read_buffer_size
)
301 png_ptr
->read_buffer
= NULL
;
302 png_ptr
->read_buffer
= NULL
;
303 png_ptr
->read_buffer_size
= 0;
304 png_free(png_ptr
, buffer
);
310 buffer
= png_voidcast(png_bytep
, png_malloc_base(png_ptr
, new_size
));
314 png_ptr
->read_buffer
= buffer
;
315 png_ptr
->read_buffer_size
= new_size
;
318 else if (warn
< 2) /* else silent */
321 png_chunk_warning(png_ptr
, "insufficient memory to read chunk");
324 png_chunk_error(png_ptr
, "insufficient memory to read chunk");
330 #endif /* READ_iCCP|iTXt|pCAL|sCAL|sPLT|tEXt|zTXt|SEQUENTIAL_READ */
332 /* png_inflate_claim: claim the zstream for some nefarious purpose that involves
333 * decompression. Returns Z_OK on success, else a zlib error code. It checks
334 * the owner but, in final release builds, just issues a warning if some other
335 * chunk apparently owns the stream. Prior to release it does a png_error.
338 png_inflate_claim(png_structrp png_ptr
, png_uint_32 owner
)
340 if (png_ptr
->zowner
!= 0)
344 PNG_STRING_FROM_CHUNK(msg
, png_ptr
->zowner
);
345 /* So the message that results is "<chunk> using zstream"; this is an
346 * internal error, but is very useful for debugging. i18n requirements
349 (void)png_safecat(msg
, (sizeof msg
), 4, " using zstream");
350 #if PNG_RELEASE_BUILD
351 png_chunk_warning(png_ptr
, msg
);
354 png_chunk_error(png_ptr
, msg
);
358 /* Implementation note: unlike 'png_deflate_claim' this internal function
359 * does not take the size of the data as an argument. Some efficiency could
360 * be gained by using this when it is known *if* the zlib stream itself does
361 * not record the number; however, this is an illusion: the original writer
362 * of the PNG may have selected a lower window size, and we really must
363 * follow that because, for systems with with limited capabilities, we
364 * would otherwise reject the application's attempts to use a smaller window
365 * size (zlib doesn't have an interface to say "this or lower"!).
367 * inflateReset2 was added to zlib 1.2.4; before this the window could not be
368 * reset, therefore it is necessary to always allocate the maximum window
369 * size with earlier zlibs just in case later compressed chunks need it.
372 int ret
; /* zlib return code */
373 #if PNG_ZLIB_VERNUM >= 0x1240
375 # if defined(PNG_SET_OPTION_SUPPORTED) && defined(PNG_MAXIMUM_INFLATE_WINDOW)
378 if (((png_ptr
->options
>> PNG_MAXIMUM_INFLATE_WINDOW
) & 3) ==
382 png_ptr
->zstream_start
= 0; /* fixed window size */
388 png_ptr
->zstream_start
= 1;
391 # define window_bits 0
395 /* Set this for safety, just in case the previous owner left pointers to
396 * memory allocations.
398 png_ptr
->zstream
.next_in
= NULL
;
399 png_ptr
->zstream
.avail_in
= 0;
400 png_ptr
->zstream
.next_out
= NULL
;
401 png_ptr
->zstream
.avail_out
= 0;
403 if ((png_ptr
->flags
& PNG_FLAG_ZSTREAM_INITIALIZED
) != 0)
405 #if PNG_ZLIB_VERNUM < 0x1240
406 ret
= inflateReset(&png_ptr
->zstream
);
408 ret
= inflateReset2(&png_ptr
->zstream
, window_bits
);
414 #if PNG_ZLIB_VERNUM < 0x1240
415 ret
= inflateInit(&png_ptr
->zstream
);
417 ret
= inflateInit2(&png_ptr
->zstream
, window_bits
);
421 png_ptr
->flags
|= PNG_FLAG_ZSTREAM_INITIALIZED
;
425 png_ptr
->zowner
= owner
;
428 png_zstream_error(png_ptr
, ret
);
438 #if PNG_ZLIB_VERNUM >= 0x1240
439 /* Handle the start of the inflate stream if we called inflateInit2(strm,0);
440 * in this case some zlib versions skip validation of the CINFO field and, in
441 * certain circumstances, libpng may end up displaying an invalid image, in
442 * contrast to implementations that call zlib in the normal way (e.g. libpng
446 png_zlib_inflate(png_structrp png_ptr
, int flush
)
448 if (png_ptr
->zstream_start
&& png_ptr
->zstream
.avail_in
> 0)
450 if ((*png_ptr
->zstream
.next_in
>> 4) > 7)
452 png_ptr
->zstream
.msg
= "invalid window size (libpng)";
456 png_ptr
->zstream_start
= 0;
459 return inflate(&png_ptr
->zstream
, flush
);
461 #endif /* Zlib >= 1.2.4 */
463 #ifdef PNG_READ_COMPRESSED_TEXT_SUPPORTED
464 /* png_inflate now returns zlib error codes including Z_OK and Z_STREAM_END to
465 * allow the caller to do multiple calls if required. If the 'finish' flag is
466 * set Z_FINISH will be passed to the final inflate() call and Z_STREAM_END must
467 * be returned or there has been a problem, otherwise Z_SYNC_FLUSH is used and
468 * Z_OK or Z_STREAM_END will be returned on success.
470 * The input and output sizes are updated to the actual amounts of data consumed
471 * or written, not the amount available (as in a z_stream). The data pointers
472 * are not changed, so the next input is (data+input_size) and the next
473 * available output is (output+output_size).
476 png_inflate(png_structrp png_ptr
, png_uint_32 owner
, int finish
,
477 /* INPUT: */ png_const_bytep input
, png_uint_32p input_size_ptr
,
478 /* OUTPUT: */ png_bytep output
, png_alloc_size_t
*output_size_ptr
)
480 if (png_ptr
->zowner
== owner
) /* Else not claimed */
483 png_alloc_size_t avail_out
= *output_size_ptr
;
484 png_uint_32 avail_in
= *input_size_ptr
;
486 /* zlib can't necessarily handle more than 65535 bytes at once (i.e. it
487 * can't even necessarily handle 65536 bytes) because the type uInt is
488 * "16 bits or more". Consequently it is necessary to chunk the input to
489 * zlib. This code uses ZLIB_IO_MAX, from pngpriv.h, as the maximum (the
490 * maximum value that can be stored in a uInt.) It is possible to set
491 * ZLIB_IO_MAX to a lower value in pngpriv.h and this may sometimes have
492 * a performance advantage, because it reduces the amount of data accessed
493 * at each step and that may give the OS more time to page it in.
495 png_ptr
->zstream
.next_in
= PNGZ_INPUT_CAST(input
);
496 /* avail_in and avail_out are set below from 'size' */
497 png_ptr
->zstream
.avail_in
= 0;
498 png_ptr
->zstream
.avail_out
= 0;
500 /* Read directly into the output if it is available (this is set to
501 * a local buffer below if output is NULL).
504 png_ptr
->zstream
.next_out
= output
;
509 Byte local_buffer
[PNG_INFLATE_BUF_SIZE
];
511 /* zlib INPUT BUFFER */
512 /* The setting of 'avail_in' used to be outside the loop; by setting it
513 * inside it is possible to chunk the input to zlib and simply rely on
514 * zlib to advance the 'next_in' pointer. This allows arbitrary
515 * amounts of data to be passed through zlib at the unavoidable cost of
516 * requiring a window save (memcpy of up to 32768 output bytes)
517 * every ZLIB_IO_MAX input bytes.
519 avail_in
+= png_ptr
->zstream
.avail_in
; /* not consumed last time */
523 if (avail_in
< avail
)
524 avail
= (uInt
)avail_in
; /* safe: < than ZLIB_IO_MAX */
527 png_ptr
->zstream
.avail_in
= avail
;
529 /* zlib OUTPUT BUFFER */
530 avail_out
+= png_ptr
->zstream
.avail_out
; /* not written last time */
532 avail
= ZLIB_IO_MAX
; /* maximum zlib can process */
536 /* Reset the output buffer each time round if output is NULL and
537 * make available the full buffer, up to 'remaining_space'
539 png_ptr
->zstream
.next_out
= local_buffer
;
540 if ((sizeof local_buffer
) < avail
)
541 avail
= (sizeof local_buffer
);
544 if (avail_out
< avail
)
545 avail
= (uInt
)avail_out
; /* safe: < ZLIB_IO_MAX */
547 png_ptr
->zstream
.avail_out
= avail
;
550 /* zlib inflate call */
551 /* In fact 'avail_out' may be 0 at this point, that happens at the end
552 * of the read when the final LZ end code was not passed at the end of
553 * the previous chunk of input data. Tell zlib if we have reached the
554 * end of the output buffer.
556 ret
= PNG_INFLATE(png_ptr
, avail_out
> 0 ? Z_NO_FLUSH
:
557 (finish
? Z_FINISH
: Z_SYNC_FLUSH
));
558 } while (ret
== Z_OK
);
560 /* For safety kill the local buffer pointer now */
562 png_ptr
->zstream
.next_out
= NULL
;
564 /* Claw back the 'size' and 'remaining_space' byte counts. */
565 avail_in
+= png_ptr
->zstream
.avail_in
;
566 avail_out
+= png_ptr
->zstream
.avail_out
;
568 /* Update the input and output sizes; the updated values are the amount
569 * consumed or written, effectively the inverse of what zlib uses.
572 *output_size_ptr
-= avail_out
;
575 *input_size_ptr
-= avail_in
;
577 /* Ensure png_ptr->zstream.msg is set (even in the success case!) */
578 png_zstream_error(png_ptr
, ret
);
584 /* This is a bad internal error. The recovery assigns to the zstream msg
585 * pointer, which is not owned by the caller, but this is safe; it's only
588 png_ptr
->zstream
.msg
= PNGZ_MSG_CAST("zstream unclaimed");
589 return Z_STREAM_ERROR
;
594 * Decompress trailing data in a chunk. The assumption is that read_buffer
595 * points at an allocated area holding the contents of a chunk with a
596 * trailing compressed part. What we get back is an allocated area
597 * holding the original prefix part and an uncompressed version of the
598 * trailing part (the malloc area passed in is freed).
601 png_decompress_chunk(png_structrp png_ptr
,
602 png_uint_32 chunklength
, png_uint_32 prefix_size
,
603 png_alloc_size_t
*newlength
/* must be initialized to the maximum! */,
604 int terminate
/*add a '\0' to the end of the uncompressed data*/)
606 /* TODO: implement different limits for different types of chunk.
608 * The caller supplies *newlength set to the maximum length of the
609 * uncompressed data, but this routine allocates space for the prefix and
610 * maybe a '\0' terminator too. We have to assume that 'prefix_size' is
611 * limited only by the maximum chunk size.
613 png_alloc_size_t limit
= PNG_SIZE_MAX
;
615 # ifdef PNG_SET_USER_LIMITS_SUPPORTED
616 if (png_ptr
->user_chunk_malloc_max
> 0 &&
617 png_ptr
->user_chunk_malloc_max
< limit
)
618 limit
= png_ptr
->user_chunk_malloc_max
;
619 # elif PNG_USER_CHUNK_MALLOC_MAX > 0
620 if (PNG_USER_CHUNK_MALLOC_MAX
< limit
)
621 limit
= PNG_USER_CHUNK_MALLOC_MAX
;
624 if (limit
>= prefix_size
+ (terminate
!= 0))
628 limit
-= prefix_size
+ (terminate
!= 0);
630 if (limit
< *newlength
)
633 /* Now try to claim the stream. */
634 ret
= png_inflate_claim(png_ptr
, png_ptr
->chunk_name
);
638 png_uint_32 lzsize
= chunklength
- prefix_size
;
640 ret
= png_inflate(png_ptr
, png_ptr
->chunk_name
, 1/*finish*/,
641 /* input: */ png_ptr
->read_buffer
+ prefix_size
, &lzsize
,
642 /* output: */ NULL
, newlength
);
644 if (ret
== Z_STREAM_END
)
646 /* Use 'inflateReset' here, not 'inflateReset2' because this
647 * preserves the previously decided window size (otherwise it would
648 * be necessary to store the previous window size.) In practice
649 * this doesn't matter anyway, because png_inflate will call inflate
650 * with Z_FINISH in almost all cases, so the window will not be
653 if (inflateReset(&png_ptr
->zstream
) == Z_OK
)
655 /* Because of the limit checks above we know that the new,
656 * expanded, size will fit in a size_t (let alone an
657 * png_alloc_size_t). Use png_malloc_base here to avoid an
660 png_alloc_size_t new_size
= *newlength
;
661 png_alloc_size_t buffer_size
= prefix_size
+ new_size
+
663 png_bytep text
= png_voidcast(png_bytep
, png_malloc_base(png_ptr
,
668 ret
= png_inflate(png_ptr
, png_ptr
->chunk_name
, 1/*finish*/,
669 png_ptr
->read_buffer
+ prefix_size
, &lzsize
,
670 text
+ prefix_size
, newlength
);
672 if (ret
== Z_STREAM_END
)
674 if (new_size
== *newlength
)
677 text
[prefix_size
+ *newlength
] = 0;
680 memcpy(text
, png_ptr
->read_buffer
, prefix_size
);
683 png_bytep old_ptr
= png_ptr
->read_buffer
;
685 png_ptr
->read_buffer
= text
;
686 png_ptr
->read_buffer_size
= buffer_size
;
687 text
= old_ptr
; /* freed below */
693 /* The size changed on the second read, there can be no
694 * guarantee that anything is correct at this point.
695 * The 'msg' pointer has been set to "unexpected end of
696 * LZ stream", which is fine, but return an error code
697 * that the caller won't accept.
699 ret
= PNG_UNEXPECTED_ZLIB_RETURN
;
703 else if (ret
== Z_OK
)
704 ret
= PNG_UNEXPECTED_ZLIB_RETURN
; /* for safety */
706 /* Free the text pointer (this is the old read_buffer on
709 png_free(png_ptr
, text
);
711 /* This really is very benign, but it's still an error because
712 * the extra space may otherwise be used as a Trojan Horse.
714 if (ret
== Z_STREAM_END
&&
715 chunklength
- prefix_size
!= lzsize
)
716 png_chunk_benign_error(png_ptr
, "extra compressed data");
721 /* Out of memory allocating the buffer */
723 png_zstream_error(png_ptr
, Z_MEM_ERROR
);
729 /* inflateReset failed, store the error message */
730 png_zstream_error(png_ptr
, ret
);
732 if (ret
== Z_STREAM_END
)
733 ret
= PNG_UNEXPECTED_ZLIB_RETURN
;
737 else if (ret
== Z_OK
)
738 ret
= PNG_UNEXPECTED_ZLIB_RETURN
;
740 /* Release the claimed stream */
744 else /* the claim failed */ if (ret
== Z_STREAM_END
) /* impossible! */
745 ret
= PNG_UNEXPECTED_ZLIB_RETURN
;
752 /* Application/configuration limits exceeded */
753 png_zstream_error(png_ptr
, Z_MEM_ERROR
);
757 #endif /* READ_COMPRESSED_TEXT */
759 #ifdef PNG_READ_iCCP_SUPPORTED
760 /* Perform a partial read and decompress, producing 'avail_out' bytes and
761 * reading from the current chunk as required.
764 png_inflate_read(png_structrp png_ptr
, png_bytep read_buffer
, uInt read_size
,
765 png_uint_32p chunk_bytes
, png_bytep next_out
, png_alloc_size_t
*out_size
,
768 if (png_ptr
->zowner
== png_ptr
->chunk_name
)
772 /* next_in and avail_in must have been initialized by the caller. */
773 png_ptr
->zstream
.next_out
= next_out
;
774 png_ptr
->zstream
.avail_out
= 0; /* set in the loop */
778 if (png_ptr
->zstream
.avail_in
== 0)
780 if (read_size
> *chunk_bytes
)
781 read_size
= (uInt
)*chunk_bytes
;
782 *chunk_bytes
-= read_size
;
785 png_crc_read(png_ptr
, read_buffer
, read_size
);
787 png_ptr
->zstream
.next_in
= read_buffer
;
788 png_ptr
->zstream
.avail_in
= read_size
;
791 if (png_ptr
->zstream
.avail_out
== 0)
793 uInt avail
= ZLIB_IO_MAX
;
794 if (avail
> *out_size
)
795 avail
= (uInt
)*out_size
;
798 png_ptr
->zstream
.avail_out
= avail
;
801 /* Use Z_SYNC_FLUSH when there is no more chunk data to ensure that all
802 * the available output is produced; this allows reading of truncated
805 ret
= PNG_INFLATE(png_ptr
,
806 *chunk_bytes
> 0 ? Z_NO_FLUSH
: (finish
? Z_FINISH
: Z_SYNC_FLUSH
));
808 while (ret
== Z_OK
&& (*out_size
> 0 || png_ptr
->zstream
.avail_out
> 0));
810 *out_size
+= png_ptr
->zstream
.avail_out
;
811 png_ptr
->zstream
.avail_out
= 0; /* Should not be required, but is safe */
813 /* Ensure the error message pointer is always set: */
814 png_zstream_error(png_ptr
, ret
);
820 png_ptr
->zstream
.msg
= PNGZ_MSG_CAST("zstream unclaimed");
821 return Z_STREAM_ERROR
;
826 /* Read and check the IDHR chunk */
829 png_handle_IHDR(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
832 png_uint_32 width
, height
;
833 int bit_depth
, color_type
, compression_type
, filter_type
;
836 png_debug(1, "in png_handle_IHDR");
838 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) != 0)
839 png_chunk_error(png_ptr
, "out of place");
841 /* Check the length */
843 png_chunk_error(png_ptr
, "invalid");
845 png_ptr
->mode
|= PNG_HAVE_IHDR
;
847 png_crc_read(png_ptr
, buf
, 13);
848 png_crc_finish(png_ptr
, 0);
850 width
= png_get_uint_31(png_ptr
, buf
);
851 height
= png_get_uint_31(png_ptr
, buf
+ 4);
854 compression_type
= buf
[10];
855 filter_type
= buf
[11];
856 interlace_type
= buf
[12];
858 /* Set internal variables */
859 png_ptr
->width
= width
;
860 png_ptr
->height
= height
;
861 png_ptr
->bit_depth
= (png_byte
)bit_depth
;
862 png_ptr
->interlaced
= (png_byte
)interlace_type
;
863 png_ptr
->color_type
= (png_byte
)color_type
;
864 #ifdef PNG_MNG_FEATURES_SUPPORTED
865 png_ptr
->filter_type
= (png_byte
)filter_type
;
867 png_ptr
->compression_type
= (png_byte
)compression_type
;
869 /* Find number of channels */
870 switch (png_ptr
->color_type
)
872 default: /* invalid, png_set_IHDR calls png_error */
873 case PNG_COLOR_TYPE_GRAY
:
874 case PNG_COLOR_TYPE_PALETTE
:
875 png_ptr
->channels
= 1;
878 case PNG_COLOR_TYPE_RGB
:
879 png_ptr
->channels
= 3;
882 case PNG_COLOR_TYPE_GRAY_ALPHA
:
883 png_ptr
->channels
= 2;
886 case PNG_COLOR_TYPE_RGB_ALPHA
:
887 png_ptr
->channels
= 4;
891 /* Set up other useful info */
892 png_ptr
->pixel_depth
= (png_byte
)(png_ptr
->bit_depth
* png_ptr
->channels
);
893 png_ptr
->rowbytes
= PNG_ROWBYTES(png_ptr
->pixel_depth
, png_ptr
->width
);
894 png_debug1(3, "bit_depth = %d", png_ptr
->bit_depth
);
895 png_debug1(3, "channels = %d", png_ptr
->channels
);
896 png_debug1(3, "rowbytes = %lu", (unsigned long)png_ptr
->rowbytes
);
897 png_set_IHDR(png_ptr
, info_ptr
, width
, height
, bit_depth
,
898 color_type
, interlace_type
, compression_type
, filter_type
);
901 /* Read and check the palette */
903 png_handle_PLTE(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
905 png_color palette
[PNG_MAX_PALETTE_LENGTH
];
906 int max_palette_length
, num
, i
;
907 #ifdef PNG_POINTER_INDEXING_SUPPORTED
911 png_debug(1, "in png_handle_PLTE");
913 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
914 png_chunk_error(png_ptr
, "missing IHDR");
916 /* Moved to before the 'after IDAT' check below because otherwise duplicate
917 * PLTE chunks are potentially ignored (the spec says there shall not be more
918 * than one PLTE, the error is not treated as benign, so this check trumps
919 * the requirement that PLTE appears before IDAT.)
921 else if ((png_ptr
->mode
& PNG_HAVE_PLTE
) != 0)
922 png_chunk_error(png_ptr
, "duplicate");
924 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
926 /* This is benign because the non-benign error happened before, when an
927 * IDAT was encountered in a color-mapped image with no PLTE.
929 png_crc_finish(png_ptr
, length
);
930 png_chunk_benign_error(png_ptr
, "out of place");
934 png_ptr
->mode
|= PNG_HAVE_PLTE
;
936 if ((png_ptr
->color_type
& PNG_COLOR_MASK_COLOR
) == 0)
938 png_crc_finish(png_ptr
, length
);
939 png_chunk_benign_error(png_ptr
, "ignored in grayscale PNG");
943 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
944 if (png_ptr
->color_type
!= PNG_COLOR_TYPE_PALETTE
)
946 png_crc_finish(png_ptr
, length
);
951 if (length
> 3*PNG_MAX_PALETTE_LENGTH
|| length
% 3)
953 png_crc_finish(png_ptr
, length
);
955 if (png_ptr
->color_type
!= PNG_COLOR_TYPE_PALETTE
)
956 png_chunk_benign_error(png_ptr
, "invalid");
959 png_chunk_error(png_ptr
, "invalid");
964 /* The cast is safe because 'length' is less than 3*PNG_MAX_PALETTE_LENGTH */
965 num
= (int)length
/ 3;
967 /* If the palette has 256 or fewer entries but is too large for the bit
968 * depth, we don't issue an error, to preserve the behavior of previous
969 * libpng versions. We silently truncate the unused extra palette entries
972 if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
973 max_palette_length
= (1 << png_ptr
->bit_depth
);
975 max_palette_length
= PNG_MAX_PALETTE_LENGTH
;
977 if (num
> max_palette_length
)
978 num
= max_palette_length
;
980 #ifdef PNG_POINTER_INDEXING_SUPPORTED
981 for (i
= 0, pal_ptr
= palette
; i
< num
; i
++, pal_ptr
++)
985 png_crc_read(png_ptr
, buf
, 3);
986 pal_ptr
->red
= buf
[0];
987 pal_ptr
->green
= buf
[1];
988 pal_ptr
->blue
= buf
[2];
991 for (i
= 0; i
< num
; i
++)
995 png_crc_read(png_ptr
, buf
, 3);
996 /* Don't depend upon png_color being any order */
997 palette
[i
].red
= buf
[0];
998 palette
[i
].green
= buf
[1];
999 palette
[i
].blue
= buf
[2];
1003 /* If we actually need the PLTE chunk (ie for a paletted image), we do
1004 * whatever the normal CRC configuration tells us. However, if we
1005 * have an RGB image, the PLTE can be considered ancillary, so
1006 * we will act as though it is.
1008 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
1009 if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
1012 png_crc_finish(png_ptr
, (int) length
- num
* 3);
1015 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
1016 else if (png_crc_error(png_ptr
) != 0) /* Only if we have a CRC error */
1018 /* If we don't want to use the data from an ancillary chunk,
1019 * we have two options: an error abort, or a warning and we
1020 * ignore the data in this chunk (which should be OK, since
1021 * it's considered ancillary for a RGB or RGBA image).
1023 * IMPLEMENTATION NOTE: this is only here because png_crc_finish uses the
1024 * chunk type to determine whether to check the ancillary or the critical
1027 if ((png_ptr
->flags
& PNG_FLAG_CRC_ANCILLARY_USE
) == 0)
1029 if ((png_ptr
->flags
& PNG_FLAG_CRC_ANCILLARY_NOWARN
) != 0)
1033 png_chunk_error(png_ptr
, "CRC error");
1036 /* Otherwise, we (optionally) emit a warning and use the chunk. */
1037 else if ((png_ptr
->flags
& PNG_FLAG_CRC_ANCILLARY_NOWARN
) == 0)
1038 png_chunk_warning(png_ptr
, "CRC error");
1042 /* TODO: png_set_PLTE has the side effect of setting png_ptr->palette to its
1043 * own copy of the palette. This has the side effect that when png_start_row
1044 * is called (this happens after any call to png_read_update_info) the
1045 * info_ptr palette gets changed. This is extremely unexpected and
1048 * Fix this by not sharing the palette in this way.
1050 png_set_PLTE(png_ptr
, info_ptr
, palette
, num
);
1052 /* The three chunks, bKGD, hIST and tRNS *must* appear after PLTE and before
1053 * IDAT. Prior to 1.6.0 this was not checked; instead the code merely
1054 * checked the apparent validity of a tRNS chunk inserted before PLTE on a
1055 * palette PNG. 1.6.0 attempts to rigorously follow the standard and
1056 * therefore does a benign error if the erroneous condition is detected *and*
1057 * cancels the tRNS if the benign error returns. The alternative is to
1058 * amend the standard since it would be rather hypocritical of the standards
1059 * maintainers to ignore it.
1061 #ifdef PNG_READ_tRNS_SUPPORTED
1062 if (png_ptr
->num_trans
> 0 ||
1063 (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_tRNS
) != 0))
1065 /* Cancel this because otherwise it would be used if the transforms
1066 * require it. Don't cancel the 'valid' flag because this would prevent
1067 * detection of duplicate chunks.
1069 png_ptr
->num_trans
= 0;
1071 if (info_ptr
!= NULL
)
1072 info_ptr
->num_trans
= 0;
1074 png_chunk_benign_error(png_ptr
, "tRNS must be after");
1078 #ifdef PNG_READ_hIST_SUPPORTED
1079 if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_hIST
) != 0)
1080 png_chunk_benign_error(png_ptr
, "hIST must be after");
1083 #ifdef PNG_READ_bKGD_SUPPORTED
1084 if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_bKGD
) != 0)
1085 png_chunk_benign_error(png_ptr
, "bKGD must be after");
1090 png_handle_IEND(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1092 png_debug(1, "in png_handle_IEND");
1094 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0 ||
1095 (png_ptr
->mode
& PNG_HAVE_IDAT
) == 0)
1096 png_chunk_error(png_ptr
, "out of place");
1098 png_ptr
->mode
|= (PNG_AFTER_IDAT
| PNG_HAVE_IEND
);
1100 png_crc_finish(png_ptr
, length
);
1103 png_chunk_benign_error(png_ptr
, "invalid");
1105 PNG_UNUSED(info_ptr
)
1108 #ifdef PNG_READ_gAMA_SUPPORTED
1110 png_handle_gAMA(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1112 png_fixed_point igamma
;
1115 png_debug(1, "in png_handle_gAMA");
1117 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1118 png_chunk_error(png_ptr
, "missing IHDR");
1120 else if ((png_ptr
->mode
& (PNG_HAVE_IDAT
|PNG_HAVE_PLTE
)) != 0)
1122 png_crc_finish(png_ptr
, length
);
1123 png_chunk_benign_error(png_ptr
, "out of place");
1129 png_crc_finish(png_ptr
, length
);
1130 png_chunk_benign_error(png_ptr
, "invalid");
1134 png_crc_read(png_ptr
, buf
, 4);
1136 if (png_crc_finish(png_ptr
, 0) != 0)
1139 igamma
= png_get_fixed_point(NULL
, buf
);
1141 png_colorspace_set_gamma(png_ptr
, &png_ptr
->colorspace
, igamma
);
1142 png_colorspace_sync(png_ptr
, info_ptr
);
1146 #ifdef PNG_READ_sBIT_SUPPORTED
1148 png_handle_sBIT(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1150 unsigned int truelen
, i
;
1151 png_byte sample_depth
;
1154 png_debug(1, "in png_handle_sBIT");
1156 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1157 png_chunk_error(png_ptr
, "missing IHDR");
1159 else if ((png_ptr
->mode
& (PNG_HAVE_IDAT
|PNG_HAVE_PLTE
)) != 0)
1161 png_crc_finish(png_ptr
, length
);
1162 png_chunk_benign_error(png_ptr
, "out of place");
1166 if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_sBIT
) != 0)
1168 png_crc_finish(png_ptr
, length
);
1169 png_chunk_benign_error(png_ptr
, "duplicate");
1173 if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
1181 truelen
= png_ptr
->channels
;
1182 sample_depth
= png_ptr
->bit_depth
;
1185 if (length
!= truelen
|| length
> 4)
1187 png_chunk_benign_error(png_ptr
, "invalid");
1188 png_crc_finish(png_ptr
, length
);
1192 buf
[0] = buf
[1] = buf
[2] = buf
[3] = sample_depth
;
1193 png_crc_read(png_ptr
, buf
, truelen
);
1195 if (png_crc_finish(png_ptr
, 0) != 0)
1198 for (i
=0; i
<truelen
; ++i
)
1200 if (buf
[i
] == 0 || buf
[i
] > sample_depth
)
1202 png_chunk_benign_error(png_ptr
, "invalid");
1207 if ((png_ptr
->color_type
& PNG_COLOR_MASK_COLOR
) != 0)
1209 png_ptr
->sig_bit
.red
= buf
[0];
1210 png_ptr
->sig_bit
.green
= buf
[1];
1211 png_ptr
->sig_bit
.blue
= buf
[2];
1212 png_ptr
->sig_bit
.alpha
= buf
[3];
1217 png_ptr
->sig_bit
.gray
= buf
[0];
1218 png_ptr
->sig_bit
.red
= buf
[0];
1219 png_ptr
->sig_bit
.green
= buf
[0];
1220 png_ptr
->sig_bit
.blue
= buf
[0];
1221 png_ptr
->sig_bit
.alpha
= buf
[1];
1224 png_set_sBIT(png_ptr
, info_ptr
, &(png_ptr
->sig_bit
));
1228 #ifdef PNG_READ_cHRM_SUPPORTED
1230 png_handle_cHRM(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1235 png_debug(1, "in png_handle_cHRM");
1237 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1238 png_chunk_error(png_ptr
, "missing IHDR");
1240 else if ((png_ptr
->mode
& (PNG_HAVE_IDAT
|PNG_HAVE_PLTE
)) != 0)
1242 png_crc_finish(png_ptr
, length
);
1243 png_chunk_benign_error(png_ptr
, "out of place");
1249 png_crc_finish(png_ptr
, length
);
1250 png_chunk_benign_error(png_ptr
, "invalid");
1254 png_crc_read(png_ptr
, buf
, 32);
1256 if (png_crc_finish(png_ptr
, 0) != 0)
1259 xy
.whitex
= png_get_fixed_point(NULL
, buf
);
1260 xy
.whitey
= png_get_fixed_point(NULL
, buf
+ 4);
1261 xy
.redx
= png_get_fixed_point(NULL
, buf
+ 8);
1262 xy
.redy
= png_get_fixed_point(NULL
, buf
+ 12);
1263 xy
.greenx
= png_get_fixed_point(NULL
, buf
+ 16);
1264 xy
.greeny
= png_get_fixed_point(NULL
, buf
+ 20);
1265 xy
.bluex
= png_get_fixed_point(NULL
, buf
+ 24);
1266 xy
.bluey
= png_get_fixed_point(NULL
, buf
+ 28);
1268 if (xy
.whitex
== PNG_FIXED_ERROR
||
1269 xy
.whitey
== PNG_FIXED_ERROR
||
1270 xy
.redx
== PNG_FIXED_ERROR
||
1271 xy
.redy
== PNG_FIXED_ERROR
||
1272 xy
.greenx
== PNG_FIXED_ERROR
||
1273 xy
.greeny
== PNG_FIXED_ERROR
||
1274 xy
.bluex
== PNG_FIXED_ERROR
||
1275 xy
.bluey
== PNG_FIXED_ERROR
)
1277 png_chunk_benign_error(png_ptr
, "invalid values");
1281 /* If a colorspace error has already been output skip this chunk */
1282 if ((png_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
) != 0)
1285 if ((png_ptr
->colorspace
.flags
& PNG_COLORSPACE_FROM_cHRM
) != 0)
1287 png_ptr
->colorspace
.flags
|= PNG_COLORSPACE_INVALID
;
1288 png_colorspace_sync(png_ptr
, info_ptr
);
1289 png_chunk_benign_error(png_ptr
, "duplicate");
1293 png_ptr
->colorspace
.flags
|= PNG_COLORSPACE_FROM_cHRM
;
1294 (void)png_colorspace_set_chromaticities(png_ptr
, &png_ptr
->colorspace
, &xy
,
1295 1/*prefer cHRM values*/);
1296 png_colorspace_sync(png_ptr
, info_ptr
);
1300 #ifdef PNG_READ_sRGB_SUPPORTED
1302 png_handle_sRGB(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1306 png_debug(1, "in png_handle_sRGB");
1308 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1309 png_chunk_error(png_ptr
, "missing IHDR");
1311 else if ((png_ptr
->mode
& (PNG_HAVE_IDAT
|PNG_HAVE_PLTE
)) != 0)
1313 png_crc_finish(png_ptr
, length
);
1314 png_chunk_benign_error(png_ptr
, "out of place");
1320 png_crc_finish(png_ptr
, length
);
1321 png_chunk_benign_error(png_ptr
, "invalid");
1325 png_crc_read(png_ptr
, &intent
, 1);
1327 if (png_crc_finish(png_ptr
, 0) != 0)
1330 /* If a colorspace error has already been output skip this chunk */
1331 if ((png_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
) != 0)
1334 /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
1337 if ((png_ptr
->colorspace
.flags
& PNG_COLORSPACE_HAVE_INTENT
) != 0)
1339 png_ptr
->colorspace
.flags
|= PNG_COLORSPACE_INVALID
;
1340 png_colorspace_sync(png_ptr
, info_ptr
);
1341 png_chunk_benign_error(png_ptr
, "too many profiles");
1345 (void)png_colorspace_set_sRGB(png_ptr
, &png_ptr
->colorspace
, intent
);
1346 png_colorspace_sync(png_ptr
, info_ptr
);
1348 #endif /* READ_sRGB */
1350 #ifdef PNG_READ_iCCP_SUPPORTED
1352 png_handle_iCCP(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1353 /* Note: this does not properly handle profiles that are > 64K under DOS */
1355 png_const_charp errmsg
= NULL
; /* error message output, or no error */
1356 int finished
= 0; /* crc checked */
1358 png_debug(1, "in png_handle_iCCP");
1360 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1361 png_chunk_error(png_ptr
, "missing IHDR");
1363 else if ((png_ptr
->mode
& (PNG_HAVE_IDAT
|PNG_HAVE_PLTE
)) != 0)
1365 png_crc_finish(png_ptr
, length
);
1366 png_chunk_benign_error(png_ptr
, "out of place");
1370 /* Consistent with all the above colorspace handling an obviously *invalid*
1371 * chunk is just ignored, so does not invalidate the color space. An
1372 * alternative is to set the 'invalid' flags at the start of this routine
1373 * and only clear them in they were not set before and all the tests pass.
1374 * The minimum 'deflate' stream is assumed to be just the 2 byte header and
1375 * 4 byte checksum. The keyword must be at least one character and there is
1376 * a terminator (0) byte and the compression method.
1380 png_crc_finish(png_ptr
, length
);
1381 png_chunk_benign_error(png_ptr
, "too short");
1385 /* If a colorspace error has already been output skip this chunk */
1386 if ((png_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
) != 0)
1388 png_crc_finish(png_ptr
, length
);
1392 /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
1395 if ((png_ptr
->colorspace
.flags
& PNG_COLORSPACE_HAVE_INTENT
) == 0)
1397 uInt read_length
, keyword_length
;
1400 /* Find the keyword; the keyword plus separator and compression method
1401 * bytes can be at most 81 characters long.
1403 read_length
= 81; /* maximum */
1404 if (read_length
> length
)
1405 read_length
= (uInt
)length
;
1407 png_crc_read(png_ptr
, (png_bytep
)keyword
, read_length
);
1408 length
-= read_length
;
1411 while (keyword_length
< 80 && keyword_length
< read_length
&&
1412 keyword
[keyword_length
] != 0)
1415 /* TODO: make the keyword checking common */
1416 if (keyword_length
>= 1 && keyword_length
<= 79)
1418 /* We only understand '0' compression - deflate - so if we get a
1419 * different value we can't safely decode the chunk.
1421 if (keyword_length
+1 < read_length
&&
1422 keyword
[keyword_length
+1] == PNG_COMPRESSION_TYPE_BASE
)
1424 read_length
-= keyword_length
+2;
1426 if (png_inflate_claim(png_ptr
, png_iCCP
) == Z_OK
)
1428 Byte profile_header
[132];
1429 Byte local_buffer
[PNG_INFLATE_BUF_SIZE
];
1430 png_alloc_size_t size
= (sizeof profile_header
);
1432 png_ptr
->zstream
.next_in
= (Bytef
*)keyword
+ (keyword_length
+2);
1433 png_ptr
->zstream
.avail_in
= read_length
;
1434 (void)png_inflate_read(png_ptr
, local_buffer
,
1435 (sizeof local_buffer
), &length
, profile_header
, &size
,
1436 0/*finish: don't, because the output is too small*/);
1440 /* We have the ICC profile header; do the basic header checks.
1442 const png_uint_32 profile_length
=
1443 png_get_uint_32(profile_header
);
1445 if (png_icc_check_length(png_ptr
, &png_ptr
->colorspace
,
1446 keyword
, profile_length
) != 0)
1448 /* The length is apparently ok, so we can check the 132
1451 if (png_icc_check_header(png_ptr
, &png_ptr
->colorspace
,
1452 keyword
, profile_length
, profile_header
,
1453 png_ptr
->color_type
) != 0)
1455 /* Now read the tag table; a variable size buffer is
1456 * needed at this point, allocate one for the whole
1457 * profile. The header check has already validated
1458 * that none of these stuff will overflow.
1460 const png_uint_32 tag_count
= png_get_uint_32(
1461 profile_header
+128);
1462 png_bytep profile
= png_read_buffer(png_ptr
,
1463 profile_length
, 2/*silent*/);
1465 if (profile
!= NULL
)
1467 memcpy(profile
, profile_header
,
1468 (sizeof profile_header
));
1470 size
= 12 * tag_count
;
1472 (void)png_inflate_read(png_ptr
, local_buffer
,
1473 (sizeof local_buffer
), &length
,
1474 profile
+ (sizeof profile_header
), &size
, 0);
1476 /* Still expect a buffer error because we expect
1477 * there to be some tag data!
1481 if (png_icc_check_tag_table(png_ptr
,
1482 &png_ptr
->colorspace
, keyword
, profile_length
,
1485 /* The profile has been validated for basic
1486 * security issues, so read the whole thing in.
1488 size
= profile_length
- (sizeof profile_header
)
1491 (void)png_inflate_read(png_ptr
, local_buffer
,
1492 (sizeof local_buffer
), &length
,
1493 profile
+ (sizeof profile_header
) +
1494 12 * tag_count
, &size
, 1/*finish*/);
1496 if (length
> 0 && !(png_ptr
->flags
&
1497 PNG_FLAG_BENIGN_ERRORS_WARN
))
1498 errmsg
= "extra compressed data";
1500 /* But otherwise allow extra data: */
1505 /* This can be handled completely, so
1508 png_chunk_warning(png_ptr
,
1509 "extra compressed data");
1512 png_crc_finish(png_ptr
, length
);
1515 # ifdef PNG_sRGB_SUPPORTED
1516 /* Check for a match against sRGB */
1517 png_icc_set_sRGB(png_ptr
,
1518 &png_ptr
->colorspace
, profile
,
1519 png_ptr
->zstream
.adler
);
1522 /* Steal the profile for info_ptr. */
1523 if (info_ptr
!= NULL
)
1525 png_free_data(png_ptr
, info_ptr
,
1528 info_ptr
->iccp_name
= png_voidcast(char*,
1529 png_malloc_base(png_ptr
,
1531 if (info_ptr
->iccp_name
!= NULL
)
1533 memcpy(info_ptr
->iccp_name
, keyword
,
1535 info_ptr
->iccp_proflen
=
1537 info_ptr
->iccp_profile
= profile
;
1538 png_ptr
->read_buffer
= NULL
; /*steal*/
1539 info_ptr
->free_me
|= PNG_FREE_ICCP
;
1540 info_ptr
->valid
|= PNG_INFO_iCCP
;
1545 png_ptr
->colorspace
.flags
|=
1546 PNG_COLORSPACE_INVALID
;
1547 errmsg
= "out of memory";
1551 /* else the profile remains in the read
1552 * buffer which gets reused for subsequent
1556 if (info_ptr
!= NULL
)
1557 png_colorspace_sync(png_ptr
, info_ptr
);
1561 png_ptr
->zowner
= 0;
1567 errmsg
= "truncated";
1569 #ifndef __COVERITY__
1571 errmsg
= png_ptr
->zstream
.msg
;
1575 /* else png_icc_check_tag_table output an error */
1578 else /* profile truncated */
1579 errmsg
= png_ptr
->zstream
.msg
;
1583 errmsg
= "out of memory";
1586 /* else png_icc_check_header output an error */
1589 /* else png_icc_check_length output an error */
1592 else /* profile truncated */
1593 errmsg
= png_ptr
->zstream
.msg
;
1595 /* Release the stream */
1596 png_ptr
->zowner
= 0;
1599 else /* png_inflate_claim failed */
1600 errmsg
= png_ptr
->zstream
.msg
;
1604 errmsg
= "bad compression method"; /* or missing */
1608 errmsg
= "bad keyword";
1612 errmsg
= "too many profiles";
1614 /* Failure: the reason is in 'errmsg' */
1616 png_crc_finish(png_ptr
, length
);
1618 png_ptr
->colorspace
.flags
|= PNG_COLORSPACE_INVALID
;
1619 png_colorspace_sync(png_ptr
, info_ptr
);
1620 if (errmsg
!= NULL
) /* else already output */
1621 png_chunk_benign_error(png_ptr
, errmsg
);
1623 #endif /* READ_iCCP */
1625 #ifdef PNG_READ_sPLT_SUPPORTED
1627 png_handle_sPLT(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1628 /* Note: this does not properly handle chunks that are > 64K under DOS */
1630 png_bytep entry_start
, buffer
;
1631 png_sPLT_t new_palette
;
1633 png_uint_32 data_length
;
1635 png_uint_32 skip
= 0;
1639 png_debug(1, "in png_handle_sPLT");
1641 #ifdef PNG_USER_LIMITS_SUPPORTED
1642 if (png_ptr
->user_chunk_cache_max
!= 0)
1644 if (png_ptr
->user_chunk_cache_max
== 1)
1646 png_crc_finish(png_ptr
, length
);
1650 if (--png_ptr
->user_chunk_cache_max
== 1)
1652 png_warning(png_ptr
, "No space in chunk cache for sPLT");
1653 png_crc_finish(png_ptr
, length
);
1659 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1660 png_chunk_error(png_ptr
, "missing IHDR");
1662 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
1664 png_crc_finish(png_ptr
, length
);
1665 png_chunk_benign_error(png_ptr
, "out of place");
1669 #ifdef PNG_MAX_MALLOC_64K
1670 if (length
> 65535U)
1672 png_crc_finish(png_ptr
, length
);
1673 png_chunk_benign_error(png_ptr
, "too large to fit in memory");
1678 buffer
= png_read_buffer(png_ptr
, length
+1, 2/*silent*/);
1681 png_crc_finish(png_ptr
, length
);
1682 png_chunk_benign_error(png_ptr
, "out of memory");
1687 /* WARNING: this may break if size_t is less than 32 bits; it is assumed
1688 * that the PNG_MAX_MALLOC_64K test is enabled in this case, but this is a
1689 * potential breakage point if the types in pngconf.h aren't exactly right.
1691 png_crc_read(png_ptr
, buffer
, length
);
1693 if (png_crc_finish(png_ptr
, skip
) != 0)
1698 for (entry_start
= buffer
; *entry_start
; entry_start
++)
1699 /* Empty loop to find end of name */ ;
1703 /* A sample depth should follow the separator, and we should be on it */
1704 if (length
< 2U || entry_start
> buffer
+ (length
- 2U))
1706 png_warning(png_ptr
, "malformed sPLT chunk");
1710 new_palette
.depth
= *entry_start
++;
1711 entry_size
= (new_palette
.depth
== 8 ? 6 : 10);
1712 /* This must fit in a png_uint_32 because it is derived from the original
1713 * chunk data length.
1715 data_length
= length
- (png_uint_32
)(entry_start
- buffer
);
1717 /* Integrity-check the data length */
1718 if ((data_length
% entry_size
) != 0)
1720 png_warning(png_ptr
, "sPLT chunk has bad length");
1724 dl
= (png_int_32
)(data_length
/ entry_size
);
1725 max_dl
= PNG_SIZE_MAX
/ (sizeof (png_sPLT_entry
));
1729 png_warning(png_ptr
, "sPLT chunk too long");
1733 new_palette
.nentries
= (png_int_32
)(data_length
/ entry_size
);
1735 new_palette
.entries
= (png_sPLT_entryp
)png_malloc_warn(
1736 png_ptr
, new_palette
.nentries
* (sizeof (png_sPLT_entry
)));
1738 if (new_palette
.entries
== NULL
)
1740 png_warning(png_ptr
, "sPLT chunk requires too much memory");
1744 #ifdef PNG_POINTER_INDEXING_SUPPORTED
1745 for (i
= 0; i
< new_palette
.nentries
; i
++)
1747 pp
= new_palette
.entries
+ i
;
1749 if (new_palette
.depth
== 8)
1751 pp
->red
= *entry_start
++;
1752 pp
->green
= *entry_start
++;
1753 pp
->blue
= *entry_start
++;
1754 pp
->alpha
= *entry_start
++;
1759 pp
->red
= png_get_uint_16(entry_start
); entry_start
+= 2;
1760 pp
->green
= png_get_uint_16(entry_start
); entry_start
+= 2;
1761 pp
->blue
= png_get_uint_16(entry_start
); entry_start
+= 2;
1762 pp
->alpha
= png_get_uint_16(entry_start
); entry_start
+= 2;
1765 pp
->frequency
= png_get_uint_16(entry_start
); entry_start
+= 2;
1768 pp
= new_palette
.entries
;
1770 for (i
= 0; i
< new_palette
.nentries
; i
++)
1773 if (new_palette
.depth
== 8)
1775 pp
[i
].red
= *entry_start
++;
1776 pp
[i
].green
= *entry_start
++;
1777 pp
[i
].blue
= *entry_start
++;
1778 pp
[i
].alpha
= *entry_start
++;
1783 pp
[i
].red
= png_get_uint_16(entry_start
); entry_start
+= 2;
1784 pp
[i
].green
= png_get_uint_16(entry_start
); entry_start
+= 2;
1785 pp
[i
].blue
= png_get_uint_16(entry_start
); entry_start
+= 2;
1786 pp
[i
].alpha
= png_get_uint_16(entry_start
); entry_start
+= 2;
1789 pp
[i
].frequency
= png_get_uint_16(entry_start
); entry_start
+= 2;
1793 /* Discard all chunk data except the name and stash that */
1794 new_palette
.name
= (png_charp
)buffer
;
1796 png_set_sPLT(png_ptr
, info_ptr
, &new_palette
, 1);
1798 png_free(png_ptr
, new_palette
.entries
);
1800 #endif /* READ_sPLT */
1802 #ifdef PNG_READ_tRNS_SUPPORTED
1804 png_handle_tRNS(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1806 png_byte readbuf
[PNG_MAX_PALETTE_LENGTH
];
1808 png_debug(1, "in png_handle_tRNS");
1810 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1811 png_chunk_error(png_ptr
, "missing IHDR");
1813 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
1815 png_crc_finish(png_ptr
, length
);
1816 png_chunk_benign_error(png_ptr
, "out of place");
1820 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_tRNS
) != 0)
1822 png_crc_finish(png_ptr
, length
);
1823 png_chunk_benign_error(png_ptr
, "duplicate");
1827 if (png_ptr
->color_type
== PNG_COLOR_TYPE_GRAY
)
1833 png_crc_finish(png_ptr
, length
);
1834 png_chunk_benign_error(png_ptr
, "invalid");
1838 png_crc_read(png_ptr
, buf
, 2);
1839 png_ptr
->num_trans
= 1;
1840 png_ptr
->trans_color
.gray
= png_get_uint_16(buf
);
1843 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_RGB
)
1849 png_crc_finish(png_ptr
, length
);
1850 png_chunk_benign_error(png_ptr
, "invalid");
1854 png_crc_read(png_ptr
, buf
, length
);
1855 png_ptr
->num_trans
= 1;
1856 png_ptr
->trans_color
.red
= png_get_uint_16(buf
);
1857 png_ptr
->trans_color
.green
= png_get_uint_16(buf
+ 2);
1858 png_ptr
->trans_color
.blue
= png_get_uint_16(buf
+ 4);
1861 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
1863 if ((png_ptr
->mode
& PNG_HAVE_PLTE
) == 0)
1865 /* TODO: is this actually an error in the ISO spec? */
1866 png_crc_finish(png_ptr
, length
);
1867 png_chunk_benign_error(png_ptr
, "out of place");
1871 if (length
> (unsigned int) png_ptr
->num_palette
||
1872 length
> (unsigned int) PNG_MAX_PALETTE_LENGTH
||
1875 png_crc_finish(png_ptr
, length
);
1876 png_chunk_benign_error(png_ptr
, "invalid");
1880 png_crc_read(png_ptr
, readbuf
, length
);
1881 png_ptr
->num_trans
= (png_uint_16
)length
;
1886 png_crc_finish(png_ptr
, length
);
1887 png_chunk_benign_error(png_ptr
, "invalid with alpha channel");
1891 if (png_crc_finish(png_ptr
, 0) != 0)
1893 png_ptr
->num_trans
= 0;
1897 /* TODO: this is a horrible side effect in the palette case because the
1898 * png_struct ends up with a pointer to the tRNS buffer owned by the
1899 * png_info. Fix this.
1901 png_set_tRNS(png_ptr
, info_ptr
, readbuf
, png_ptr
->num_trans
,
1902 &(png_ptr
->trans_color
));
1906 #ifdef PNG_READ_bKGD_SUPPORTED
1908 png_handle_bKGD(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1910 unsigned int truelen
;
1912 png_color_16 background
;
1914 png_debug(1, "in png_handle_bKGD");
1916 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1917 png_chunk_error(png_ptr
, "missing IHDR");
1919 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0 ||
1920 (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
&&
1921 (png_ptr
->mode
& PNG_HAVE_PLTE
) == 0))
1923 png_crc_finish(png_ptr
, length
);
1924 png_chunk_benign_error(png_ptr
, "out of place");
1928 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_bKGD
) != 0)
1930 png_crc_finish(png_ptr
, length
);
1931 png_chunk_benign_error(png_ptr
, "duplicate");
1935 if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
1938 else if ((png_ptr
->color_type
& PNG_COLOR_MASK_COLOR
) != 0)
1944 if (length
!= truelen
)
1946 png_crc_finish(png_ptr
, length
);
1947 png_chunk_benign_error(png_ptr
, "invalid");
1951 png_crc_read(png_ptr
, buf
, truelen
);
1953 if (png_crc_finish(png_ptr
, 0) != 0)
1956 /* We convert the index value into RGB components so that we can allow
1957 * arbitrary RGB values for background when we have transparency, and
1958 * so it is easy to determine the RGB values of the background color
1959 * from the info_ptr struct.
1961 if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
1963 background
.index
= buf
[0];
1965 if (info_ptr
!= NULL
&& info_ptr
->num_palette
!= 0)
1967 if (buf
[0] >= info_ptr
->num_palette
)
1969 png_chunk_benign_error(png_ptr
, "invalid index");
1973 background
.red
= (png_uint_16
)png_ptr
->palette
[buf
[0]].red
;
1974 background
.green
= (png_uint_16
)png_ptr
->palette
[buf
[0]].green
;
1975 background
.blue
= (png_uint_16
)png_ptr
->palette
[buf
[0]].blue
;
1979 background
.red
= background
.green
= background
.blue
= 0;
1981 background
.gray
= 0;
1984 else if ((png_ptr
->color_type
& PNG_COLOR_MASK_COLOR
) == 0) /* GRAY */
1986 background
.index
= 0;
1990 background
.gray
= png_get_uint_16(buf
);
1995 background
.index
= 0;
1996 background
.red
= png_get_uint_16(buf
);
1997 background
.green
= png_get_uint_16(buf
+ 2);
1998 background
.blue
= png_get_uint_16(buf
+ 4);
1999 background
.gray
= 0;
2002 png_set_bKGD(png_ptr
, info_ptr
, &background
);
2006 #ifdef PNG_READ_hIST_SUPPORTED
2008 png_handle_hIST(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2010 unsigned int num
, i
;
2011 png_uint_16 readbuf
[PNG_MAX_PALETTE_LENGTH
];
2013 png_debug(1, "in png_handle_hIST");
2015 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2016 png_chunk_error(png_ptr
, "missing IHDR");
2018 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0 ||
2019 (png_ptr
->mode
& PNG_HAVE_PLTE
) == 0)
2021 png_crc_finish(png_ptr
, length
);
2022 png_chunk_benign_error(png_ptr
, "out of place");
2026 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_hIST
) != 0)
2028 png_crc_finish(png_ptr
, length
);
2029 png_chunk_benign_error(png_ptr
, "duplicate");
2035 if (num
!= (unsigned int) png_ptr
->num_palette
||
2036 num
> (unsigned int) PNG_MAX_PALETTE_LENGTH
)
2038 png_crc_finish(png_ptr
, length
);
2039 png_chunk_benign_error(png_ptr
, "invalid");
2043 for (i
= 0; i
< num
; i
++)
2047 png_crc_read(png_ptr
, buf
, 2);
2048 readbuf
[i
] = png_get_uint_16(buf
);
2051 if (png_crc_finish(png_ptr
, 0) != 0)
2054 png_set_hIST(png_ptr
, info_ptr
, readbuf
);
2058 #ifdef PNG_READ_pHYs_SUPPORTED
2060 png_handle_pHYs(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2063 png_uint_32 res_x
, res_y
;
2066 png_debug(1, "in png_handle_pHYs");
2068 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2069 png_chunk_error(png_ptr
, "missing IHDR");
2071 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2073 png_crc_finish(png_ptr
, length
);
2074 png_chunk_benign_error(png_ptr
, "out of place");
2078 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_pHYs
) != 0)
2080 png_crc_finish(png_ptr
, length
);
2081 png_chunk_benign_error(png_ptr
, "duplicate");
2087 png_crc_finish(png_ptr
, length
);
2088 png_chunk_benign_error(png_ptr
, "invalid");
2092 png_crc_read(png_ptr
, buf
, 9);
2094 if (png_crc_finish(png_ptr
, 0) != 0)
2097 res_x
= png_get_uint_32(buf
);
2098 res_y
= png_get_uint_32(buf
+ 4);
2100 png_set_pHYs(png_ptr
, info_ptr
, res_x
, res_y
, unit_type
);
2104 #ifdef PNG_READ_oFFs_SUPPORTED
2106 png_handle_oFFs(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2109 png_int_32 offset_x
, offset_y
;
2112 png_debug(1, "in png_handle_oFFs");
2114 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2115 png_chunk_error(png_ptr
, "missing IHDR");
2117 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2119 png_crc_finish(png_ptr
, length
);
2120 png_chunk_benign_error(png_ptr
, "out of place");
2124 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_oFFs
) != 0)
2126 png_crc_finish(png_ptr
, length
);
2127 png_chunk_benign_error(png_ptr
, "duplicate");
2133 png_crc_finish(png_ptr
, length
);
2134 png_chunk_benign_error(png_ptr
, "invalid");
2138 png_crc_read(png_ptr
, buf
, 9);
2140 if (png_crc_finish(png_ptr
, 0) != 0)
2143 offset_x
= png_get_int_32(buf
);
2144 offset_y
= png_get_int_32(buf
+ 4);
2146 png_set_oFFs(png_ptr
, info_ptr
, offset_x
, offset_y
, unit_type
);
2150 #ifdef PNG_READ_pCAL_SUPPORTED
2151 /* Read the pCAL chunk (described in the PNG Extensions document) */
2153 png_handle_pCAL(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2156 png_byte type
, nparams
;
2157 png_bytep buffer
, buf
, units
, endptr
;
2161 png_debug(1, "in png_handle_pCAL");
2163 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2164 png_chunk_error(png_ptr
, "missing IHDR");
2166 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2168 png_crc_finish(png_ptr
, length
);
2169 png_chunk_benign_error(png_ptr
, "out of place");
2173 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_pCAL
) != 0)
2175 png_crc_finish(png_ptr
, length
);
2176 png_chunk_benign_error(png_ptr
, "duplicate");
2180 png_debug1(2, "Allocating and reading pCAL chunk data (%u bytes)",
2183 buffer
= png_read_buffer(png_ptr
, length
+1, 2/*silent*/);
2187 png_crc_finish(png_ptr
, length
);
2188 png_chunk_benign_error(png_ptr
, "out of memory");
2192 png_crc_read(png_ptr
, buffer
, length
);
2194 if (png_crc_finish(png_ptr
, 0) != 0)
2197 buffer
[length
] = 0; /* Null terminate the last string */
2199 png_debug(3, "Finding end of pCAL purpose string");
2200 for (buf
= buffer
; *buf
; buf
++)
2203 endptr
= buffer
+ length
;
2205 /* We need to have at least 12 bytes after the purpose string
2206 * in order to get the parameter information.
2208 if (endptr
- buf
<= 12)
2210 png_chunk_benign_error(png_ptr
, "invalid");
2214 png_debug(3, "Reading pCAL X0, X1, type, nparams, and units");
2215 X0
= png_get_int_32((png_bytep
)buf
+1);
2216 X1
= png_get_int_32((png_bytep
)buf
+5);
2221 png_debug(3, "Checking pCAL equation type and number of parameters");
2222 /* Check that we have the right number of parameters for known
2225 if ((type
== PNG_EQUATION_LINEAR
&& nparams
!= 2) ||
2226 (type
== PNG_EQUATION_BASE_E
&& nparams
!= 3) ||
2227 (type
== PNG_EQUATION_ARBITRARY
&& nparams
!= 3) ||
2228 (type
== PNG_EQUATION_HYPERBOLIC
&& nparams
!= 4))
2230 png_chunk_benign_error(png_ptr
, "invalid parameter count");
2234 else if (type
>= PNG_EQUATION_LAST
)
2236 png_chunk_benign_error(png_ptr
, "unrecognized equation type");
2239 for (buf
= units
; *buf
; buf
++)
2240 /* Empty loop to move past the units string. */ ;
2242 png_debug(3, "Allocating pCAL parameters array");
2244 params
= png_voidcast(png_charpp
, png_malloc_warn(png_ptr
,
2245 nparams
* (sizeof (png_charp
))));
2249 png_chunk_benign_error(png_ptr
, "out of memory");
2253 /* Get pointers to the start of each parameter string. */
2254 for (i
= 0; i
< nparams
; i
++)
2256 buf
++; /* Skip the null string terminator from previous parameter. */
2258 png_debug1(3, "Reading pCAL parameter %d", i
);
2260 for (params
[i
] = (png_charp
)buf
; buf
<= endptr
&& *buf
!= 0; buf
++)
2261 /* Empty loop to move past each parameter string */ ;
2263 /* Make sure we haven't run out of data yet */
2266 png_free(png_ptr
, params
);
2267 png_chunk_benign_error(png_ptr
, "invalid data");
2272 png_set_pCAL(png_ptr
, info_ptr
, (png_charp
)buffer
, X0
, X1
, type
, nparams
,
2273 (png_charp
)units
, params
);
2275 png_free(png_ptr
, params
);
2279 #ifdef PNG_READ_sCAL_SUPPORTED
2280 /* Read the sCAL chunk */
2282 png_handle_sCAL(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2288 png_debug(1, "in png_handle_sCAL");
2290 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2291 png_chunk_error(png_ptr
, "missing IHDR");
2293 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2295 png_crc_finish(png_ptr
, length
);
2296 png_chunk_benign_error(png_ptr
, "out of place");
2300 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_sCAL
) != 0)
2302 png_crc_finish(png_ptr
, length
);
2303 png_chunk_benign_error(png_ptr
, "duplicate");
2307 /* Need unit type, width, \0, height: minimum 4 bytes */
2308 else if (length
< 4)
2310 png_crc_finish(png_ptr
, length
);
2311 png_chunk_benign_error(png_ptr
, "invalid");
2315 png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)",
2318 buffer
= png_read_buffer(png_ptr
, length
+1, 2/*silent*/);
2322 png_chunk_benign_error(png_ptr
, "out of memory");
2323 png_crc_finish(png_ptr
, length
);
2327 png_crc_read(png_ptr
, buffer
, length
);
2328 buffer
[length
] = 0; /* Null terminate the last string */
2330 if (png_crc_finish(png_ptr
, 0) != 0)
2333 /* Validate the unit. */
2334 if (buffer
[0] != 1 && buffer
[0] != 2)
2336 png_chunk_benign_error(png_ptr
, "invalid unit");
2340 /* Validate the ASCII numbers, need two ASCII numbers separated by
2341 * a '\0' and they need to fit exactly in the chunk data.
2346 if (png_check_fp_number((png_const_charp
)buffer
, length
, &state
, &i
) == 0 ||
2347 i
>= length
|| buffer
[i
++] != 0)
2348 png_chunk_benign_error(png_ptr
, "bad width format");
2350 else if (PNG_FP_IS_POSITIVE(state
) == 0)
2351 png_chunk_benign_error(png_ptr
, "non-positive width");
2355 png_size_t heighti
= i
;
2358 if (png_check_fp_number((png_const_charp
)buffer
, length
,
2359 &state
, &i
) == 0 || i
!= length
)
2360 png_chunk_benign_error(png_ptr
, "bad height format");
2362 else if (PNG_FP_IS_POSITIVE(state
) == 0)
2363 png_chunk_benign_error(png_ptr
, "non-positive height");
2366 /* This is the (only) success case. */
2367 png_set_sCAL_s(png_ptr
, info_ptr
, buffer
[0],
2368 (png_charp
)buffer
+1, (png_charp
)buffer
+heighti
);
2373 #ifdef PNG_READ_tIME_SUPPORTED
2375 png_handle_tIME(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2380 png_debug(1, "in png_handle_tIME");
2382 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2383 png_chunk_error(png_ptr
, "missing IHDR");
2385 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_tIME
) != 0)
2387 png_crc_finish(png_ptr
, length
);
2388 png_chunk_benign_error(png_ptr
, "duplicate");
2392 if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2393 png_ptr
->mode
|= PNG_AFTER_IDAT
;
2397 png_crc_finish(png_ptr
, length
);
2398 png_chunk_benign_error(png_ptr
, "invalid");
2402 png_crc_read(png_ptr
, buf
, 7);
2404 if (png_crc_finish(png_ptr
, 0) != 0)
2407 mod_time
.second
= buf
[6];
2408 mod_time
.minute
= buf
[5];
2409 mod_time
.hour
= buf
[4];
2410 mod_time
.day
= buf
[3];
2411 mod_time
.month
= buf
[2];
2412 mod_time
.year
= png_get_uint_16(buf
);
2414 png_set_tIME(png_ptr
, info_ptr
, &mod_time
);
2418 #ifdef PNG_READ_tEXt_SUPPORTED
2419 /* Note: this does not properly handle chunks that are > 64K under DOS */
2421 png_handle_tEXt(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2427 png_uint_32 skip
= 0;
2429 png_debug(1, "in png_handle_tEXt");
2431 #ifdef PNG_USER_LIMITS_SUPPORTED
2432 if (png_ptr
->user_chunk_cache_max
!= 0)
2434 if (png_ptr
->user_chunk_cache_max
== 1)
2436 png_crc_finish(png_ptr
, length
);
2440 if (--png_ptr
->user_chunk_cache_max
== 1)
2442 png_crc_finish(png_ptr
, length
);
2443 png_chunk_benign_error(png_ptr
, "no space in chunk cache");
2449 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2450 png_chunk_error(png_ptr
, "missing IHDR");
2452 if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2453 png_ptr
->mode
|= PNG_AFTER_IDAT
;
2455 #ifdef PNG_MAX_MALLOC_64K
2456 if (length
> 65535U)
2458 png_crc_finish(png_ptr
, length
);
2459 png_chunk_benign_error(png_ptr
, "too large to fit in memory");
2464 buffer
= png_read_buffer(png_ptr
, length
+1, 1/*warn*/);
2468 png_chunk_benign_error(png_ptr
, "out of memory");
2472 png_crc_read(png_ptr
, buffer
, length
);
2474 if (png_crc_finish(png_ptr
, skip
) != 0)
2477 key
= (png_charp
)buffer
;
2480 for (text
= key
; *text
; text
++)
2481 /* Empty loop to find end of key */ ;
2483 if (text
!= key
+ length
)
2486 text_info
.compression
= PNG_TEXT_COMPRESSION_NONE
;
2487 text_info
.key
= key
;
2488 text_info
.lang
= NULL
;
2489 text_info
.lang_key
= NULL
;
2490 text_info
.itxt_length
= 0;
2491 text_info
.text
= text
;
2492 text_info
.text_length
= strlen(text
);
2494 if (png_set_text_2(png_ptr
, info_ptr
, &text_info
, 1) != 0)
2495 png_warning(png_ptr
, "Insufficient memory to process text chunk");
2499 #ifdef PNG_READ_zTXt_SUPPORTED
2500 /* Note: this does not correctly handle chunks that are > 64K under DOS */
2502 png_handle_zTXt(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2504 png_const_charp errmsg
= NULL
;
2506 png_uint_32 keyword_length
;
2508 png_debug(1, "in png_handle_zTXt");
2510 #ifdef PNG_USER_LIMITS_SUPPORTED
2511 if (png_ptr
->user_chunk_cache_max
!= 0)
2513 if (png_ptr
->user_chunk_cache_max
== 1)
2515 png_crc_finish(png_ptr
, length
);
2519 if (--png_ptr
->user_chunk_cache_max
== 1)
2521 png_crc_finish(png_ptr
, length
);
2522 png_chunk_benign_error(png_ptr
, "no space in chunk cache");
2528 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2529 png_chunk_error(png_ptr
, "missing IHDR");
2531 if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2532 png_ptr
->mode
|= PNG_AFTER_IDAT
;
2534 buffer
= png_read_buffer(png_ptr
, length
, 2/*silent*/);
2538 png_crc_finish(png_ptr
, length
);
2539 png_chunk_benign_error(png_ptr
, "out of memory");
2543 png_crc_read(png_ptr
, buffer
, length
);
2545 if (png_crc_finish(png_ptr
, 0) != 0)
2548 /* TODO: also check that the keyword contents match the spec! */
2549 for (keyword_length
= 0;
2550 keyword_length
< length
&& buffer
[keyword_length
] != 0;
2552 /* Empty loop to find end of name */ ;
2554 if (keyword_length
> 79 || keyword_length
< 1)
2555 errmsg
= "bad keyword";
2557 /* zTXt must have some LZ data after the keyword, although it may expand to
2558 * zero bytes; we need a '\0' at the end of the keyword, the compression type
2561 else if (keyword_length
+ 3 > length
)
2562 errmsg
= "truncated";
2564 else if (buffer
[keyword_length
+1] != PNG_COMPRESSION_TYPE_BASE
)
2565 errmsg
= "unknown compression type";
2569 png_alloc_size_t uncompressed_length
= PNG_SIZE_MAX
;
2571 /* TODO: at present png_decompress_chunk imposes a single application
2572 * level memory limit, this should be split to different values for iCCP
2575 if (png_decompress_chunk(png_ptr
, length
, keyword_length
+2,
2576 &uncompressed_length
, 1/*terminate*/) == Z_STREAM_END
)
2580 /* It worked; png_ptr->read_buffer now looks like a tEXt chunk except
2581 * for the extra compression type byte and the fact that it isn't
2582 * necessarily '\0' terminated.
2584 buffer
= png_ptr
->read_buffer
;
2585 buffer
[uncompressed_length
+(keyword_length
+2)] = 0;
2587 text
.compression
= PNG_TEXT_COMPRESSION_zTXt
;
2588 text
.key
= (png_charp
)buffer
;
2589 text
.text
= (png_charp
)(buffer
+ keyword_length
+2);
2590 text
.text_length
= uncompressed_length
;
2591 text
.itxt_length
= 0;
2593 text
.lang_key
= NULL
;
2595 if (png_set_text_2(png_ptr
, info_ptr
, &text
, 1) != 0)
2596 errmsg
= "insufficient memory";
2600 errmsg
= png_ptr
->zstream
.msg
;
2604 png_chunk_benign_error(png_ptr
, errmsg
);
2608 #ifdef PNG_READ_iTXt_SUPPORTED
2609 /* Note: this does not correctly handle chunks that are > 64K under DOS */
2611 png_handle_iTXt(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2613 png_const_charp errmsg
= NULL
;
2615 png_uint_32 prefix_length
;
2617 png_debug(1, "in png_handle_iTXt");
2619 #ifdef PNG_USER_LIMITS_SUPPORTED
2620 if (png_ptr
->user_chunk_cache_max
!= 0)
2622 if (png_ptr
->user_chunk_cache_max
== 1)
2624 png_crc_finish(png_ptr
, length
);
2628 if (--png_ptr
->user_chunk_cache_max
== 1)
2630 png_crc_finish(png_ptr
, length
);
2631 png_chunk_benign_error(png_ptr
, "no space in chunk cache");
2637 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2638 png_chunk_error(png_ptr
, "missing IHDR");
2640 if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2641 png_ptr
->mode
|= PNG_AFTER_IDAT
;
2643 buffer
= png_read_buffer(png_ptr
, length
+1, 1/*warn*/);
2647 png_crc_finish(png_ptr
, length
);
2648 png_chunk_benign_error(png_ptr
, "out of memory");
2652 png_crc_read(png_ptr
, buffer
, length
);
2654 if (png_crc_finish(png_ptr
, 0) != 0)
2657 /* First the keyword. */
2658 for (prefix_length
=0;
2659 prefix_length
< length
&& buffer
[prefix_length
] != 0;
2663 /* Perform a basic check on the keyword length here. */
2664 if (prefix_length
> 79 || prefix_length
< 1)
2665 errmsg
= "bad keyword";
2667 /* Expect keyword, compression flag, compression type, language, translated
2668 * keyword (both may be empty but are 0 terminated) then the text, which may
2671 else if (prefix_length
+ 5 > length
)
2672 errmsg
= "truncated";
2674 else if (buffer
[prefix_length
+1] == 0 ||
2675 (buffer
[prefix_length
+1] == 1 &&
2676 buffer
[prefix_length
+2] == PNG_COMPRESSION_TYPE_BASE
))
2678 int compressed
= buffer
[prefix_length
+1] != 0;
2679 png_uint_32 language_offset
, translated_keyword_offset
;
2680 png_alloc_size_t uncompressed_length
= 0;
2682 /* Now the language tag */
2684 language_offset
= prefix_length
;
2686 for (; prefix_length
< length
&& buffer
[prefix_length
] != 0;
2690 /* WARNING: the length may be invalid here, this is checked below. */
2691 translated_keyword_offset
= ++prefix_length
;
2693 for (; prefix_length
< length
&& buffer
[prefix_length
] != 0;
2697 /* prefix_length should now be at the trailing '\0' of the translated
2698 * keyword, but it may already be over the end. None of this arithmetic
2699 * can overflow because chunks are at most 2^31 bytes long, but on 16-bit
2700 * systems the available allocation may overflow.
2704 if (compressed
== 0 && prefix_length
<= length
)
2705 uncompressed_length
= length
- prefix_length
;
2707 else if (compressed
!= 0 && prefix_length
< length
)
2709 uncompressed_length
= PNG_SIZE_MAX
;
2711 /* TODO: at present png_decompress_chunk imposes a single application
2712 * level memory limit, this should be split to different values for
2713 * iCCP and text chunks.
2715 if (png_decompress_chunk(png_ptr
, length
, prefix_length
,
2716 &uncompressed_length
, 1/*terminate*/) == Z_STREAM_END
)
2717 buffer
= png_ptr
->read_buffer
;
2720 errmsg
= png_ptr
->zstream
.msg
;
2724 errmsg
= "truncated";
2730 buffer
[uncompressed_length
+prefix_length
] = 0;
2732 if (compressed
== 0)
2733 text
.compression
= PNG_ITXT_COMPRESSION_NONE
;
2736 text
.compression
= PNG_ITXT_COMPRESSION_zTXt
;
2738 text
.key
= (png_charp
)buffer
;
2739 text
.lang
= (png_charp
)buffer
+ language_offset
;
2740 text
.lang_key
= (png_charp
)buffer
+ translated_keyword_offset
;
2741 text
.text
= (png_charp
)buffer
+ prefix_length
;
2742 text
.text_length
= 0;
2743 text
.itxt_length
= uncompressed_length
;
2745 if (png_set_text_2(png_ptr
, info_ptr
, &text
, 1) != 0)
2746 errmsg
= "insufficient memory";
2751 errmsg
= "bad compression info";
2754 png_chunk_benign_error(png_ptr
, errmsg
);
2758 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
2759 /* Utility function for png_handle_unknown; set up png_ptr::unknown_chunk */
2761 png_cache_unknown_chunk(png_structrp png_ptr
, png_uint_32 length
)
2763 png_alloc_size_t limit
= PNG_SIZE_MAX
;
2765 if (png_ptr
->unknown_chunk
.data
!= NULL
)
2767 png_free(png_ptr
, png_ptr
->unknown_chunk
.data
);
2768 png_ptr
->unknown_chunk
.data
= NULL
;
2771 # ifdef PNG_SET_USER_LIMITS_SUPPORTED
2772 if (png_ptr
->user_chunk_malloc_max
> 0 &&
2773 png_ptr
->user_chunk_malloc_max
< limit
)
2774 limit
= png_ptr
->user_chunk_malloc_max
;
2776 # elif PNG_USER_CHUNK_MALLOC_MAX > 0
2777 if (PNG_USER_CHUNK_MALLOC_MAX
< limit
)
2778 limit
= PNG_USER_CHUNK_MALLOC_MAX
;
2781 if (length
<= limit
)
2783 PNG_CSTRING_FROM_CHUNK(png_ptr
->unknown_chunk
.name
, png_ptr
->chunk_name
);
2784 /* The following is safe because of the PNG_SIZE_MAX init above */
2785 png_ptr
->unknown_chunk
.size
= (png_size_t
)length
/*SAFE*/;
2786 /* 'mode' is a flag array, only the bottom four bits matter here */
2787 png_ptr
->unknown_chunk
.location
= (png_byte
)png_ptr
->mode
/*SAFE*/;
2790 png_ptr
->unknown_chunk
.data
= NULL
;
2794 /* Do a 'warn' here - it is handled below. */
2795 png_ptr
->unknown_chunk
.data
= png_voidcast(png_bytep
,
2796 png_malloc_warn(png_ptr
, length
));
2800 if (png_ptr
->unknown_chunk
.data
== NULL
&& length
> 0)
2802 /* This is benign because we clean up correctly */
2803 png_crc_finish(png_ptr
, length
);
2804 png_chunk_benign_error(png_ptr
, "unknown chunk exceeds memory limits");
2811 png_crc_read(png_ptr
, png_ptr
->unknown_chunk
.data
, length
);
2812 png_crc_finish(png_ptr
, 0);
2816 #endif /* READ_UNKNOWN_CHUNKS */
2818 /* Handle an unknown, or known but disabled, chunk */
2820 png_handle_unknown(png_structrp png_ptr
, png_inforp info_ptr
,
2821 png_uint_32 length
, int keep
)
2823 int handled
= 0; /* the chunk was handled */
2825 png_debug(1, "in png_handle_unknown");
2827 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
2828 /* NOTE: this code is based on the code in libpng-1.4.12 except for fixing
2829 * the bug which meant that setting a non-default behavior for a specific
2830 * chunk would be ignored (the default was always used unless a user
2831 * callback was installed).
2833 * 'keep' is the value from the png_chunk_unknown_handling, the setting for
2834 * this specific chunk_name, if PNG_HANDLE_AS_UNKNOWN_SUPPORTED, if not it
2835 * will always be PNG_HANDLE_CHUNK_AS_DEFAULT and it needs to be set here.
2836 * This is just an optimization to avoid multiple calls to the lookup
2839 # ifndef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
2840 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
2841 keep
= png_chunk_unknown_handling(png_ptr
, png_ptr
->chunk_name
);
2845 /* One of the following methods will read the chunk or skip it (at least one
2846 * of these is always defined because this is the only way to switch on
2847 * PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
2849 # ifdef PNG_READ_USER_CHUNKS_SUPPORTED
2850 /* The user callback takes precedence over the chunk keep value, but the
2851 * keep value is still required to validate a save of a critical chunk.
2853 if (png_ptr
->read_user_chunk_fn
!= NULL
)
2855 if (png_cache_unknown_chunk(png_ptr
, length
) != 0)
2857 /* Callback to user unknown chunk handler */
2858 int ret
= (*(png_ptr
->read_user_chunk_fn
))(png_ptr
,
2859 &png_ptr
->unknown_chunk
);
2862 * negative: An error occurred; png_chunk_error will be called.
2863 * zero: The chunk was not handled, the chunk will be discarded
2864 * unless png_set_keep_unknown_chunks has been used to set
2865 * a 'keep' behavior for this particular chunk, in which
2866 * case that will be used. A critical chunk will cause an
2867 * error at this point unless it is to be saved.
2868 * positive: The chunk was handled, libpng will ignore/discard it.
2871 png_chunk_error(png_ptr
, "error in user chunk");
2875 /* If the keep value is 'default' or 'never' override it, but
2876 * still error out on critical chunks unless the keep value is
2877 * 'always' While this is weird it is the behavior in 1.4.12.
2878 * A possible improvement would be to obey the value set for the
2879 * chunk, but this would be an API change that would probably
2880 * damage some applications.
2882 * The png_app_warning below catches the case that matters, where
2883 * the application has not set specific save or ignore for this
2884 * chunk or global save or ignore.
2886 if (keep
< PNG_HANDLE_CHUNK_IF_SAFE
)
2888 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
2889 if (png_ptr
->unknown_default
< PNG_HANDLE_CHUNK_IF_SAFE
)
2891 png_chunk_warning(png_ptr
, "Saving unknown chunk:");
2892 png_app_warning(png_ptr
,
2893 "forcing save of an unhandled chunk;"
2894 " please call png_set_keep_unknown_chunks");
2895 /* with keep = PNG_HANDLE_CHUNK_IF_SAFE */
2898 keep
= PNG_HANDLE_CHUNK_IF_SAFE
;
2902 else /* chunk was handled */
2905 /* Critical chunks can be safely discarded at this point. */
2906 keep
= PNG_HANDLE_CHUNK_NEVER
;
2911 keep
= PNG_HANDLE_CHUNK_NEVER
; /* insufficient memory */
2915 /* Use the SAVE_UNKNOWN_CHUNKS code or skip the chunk */
2916 # endif /* READ_USER_CHUNKS */
2918 # ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
2920 /* keep is currently just the per-chunk setting, if there was no
2921 * setting change it to the global default now (not that this may
2922 * still be AS_DEFAULT) then obtain the cache of the chunk if required,
2923 * if not simply skip the chunk.
2925 if (keep
== PNG_HANDLE_CHUNK_AS_DEFAULT
)
2926 keep
= png_ptr
->unknown_default
;
2928 if (keep
== PNG_HANDLE_CHUNK_ALWAYS
||
2929 (keep
== PNG_HANDLE_CHUNK_IF_SAFE
&&
2930 PNG_CHUNK_ANCILLARY(png_ptr
->chunk_name
)))
2932 if (png_cache_unknown_chunk(png_ptr
, length
) == 0)
2933 keep
= PNG_HANDLE_CHUNK_NEVER
;
2937 png_crc_finish(png_ptr
, length
);
2940 # ifndef PNG_READ_USER_CHUNKS_SUPPORTED
2941 # error no method to support READ_UNKNOWN_CHUNKS
2945 /* If here there is no read callback pointer set and no support is
2946 * compiled in to just save the unknown chunks, so simply skip this
2947 * chunk. If 'keep' is something other than AS_DEFAULT or NEVER then
2948 * the app has erroneously asked for unknown chunk saving when there
2951 if (keep
> PNG_HANDLE_CHUNK_NEVER
)
2952 png_app_error(png_ptr
, "no unknown chunk support available");
2954 png_crc_finish(png_ptr
, length
);
2958 # ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
2959 /* Now store the chunk in the chunk list if appropriate, and if the limits
2962 if (keep
== PNG_HANDLE_CHUNK_ALWAYS
||
2963 (keep
== PNG_HANDLE_CHUNK_IF_SAFE
&&
2964 PNG_CHUNK_ANCILLARY(png_ptr
->chunk_name
)))
2966 # ifdef PNG_USER_LIMITS_SUPPORTED
2967 switch (png_ptr
->user_chunk_cache_max
)
2970 png_ptr
->user_chunk_cache_max
= 1;
2971 png_chunk_benign_error(png_ptr
, "no space in chunk cache");
2974 /* NOTE: prior to 1.6.0 this case resulted in an unknown critical
2975 * chunk being skipped, now there will be a hard error below.
2979 default: /* not at limit */
2980 --(png_ptr
->user_chunk_cache_max
);
2982 case 0: /* no limit */
2983 # endif /* USER_LIMITS */
2984 /* Here when the limit isn't reached or when limits are compiled
2985 * out; store the chunk.
2987 png_set_unknown_chunks(png_ptr
, info_ptr
,
2988 &png_ptr
->unknown_chunk
, 1);
2990 # ifdef PNG_USER_LIMITS_SUPPORTED
2995 # else /* no store support: the chunk must be handled by the user callback */
2996 PNG_UNUSED(info_ptr
)
2999 /* Regardless of the error handling below the cached data (if any) can be
3000 * freed now. Notice that the data is not freed if there is a png_error, but
3001 * it will be freed by destroy_read_struct.
3003 if (png_ptr
->unknown_chunk
.data
!= NULL
)
3004 png_free(png_ptr
, png_ptr
->unknown_chunk
.data
);
3005 png_ptr
->unknown_chunk
.data
= NULL
;
3007 #else /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */
3008 /* There is no support to read an unknown chunk, so just skip it. */
3009 png_crc_finish(png_ptr
, length
);
3010 PNG_UNUSED(info_ptr
)
3012 #endif /* !READ_UNKNOWN_CHUNKS */
3014 /* Check for unhandled critical chunks */
3015 if (handled
== 0 && PNG_CHUNK_CRITICAL(png_ptr
->chunk_name
))
3016 png_chunk_error(png_ptr
, "unhandled critical chunk");
3019 /* This function is called to verify that a chunk name is valid.
3020 * This function can't have the "critical chunk check" incorporated
3021 * into it, since in the future we will need to be able to call user
3022 * functions to handle unknown critical chunks after we check that
3023 * the chunk name itself is valid.
3026 /* Bit hacking: the test for an invalid byte in the 4 byte chunk name is:
3028 * ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
3032 png_check_chunk_name(png_structrp png_ptr
, png_uint_32 chunk_name
)
3036 png_debug(1, "in png_check_chunk_name");
3038 for (i
=1; i
<=4; ++i
)
3040 int c
= chunk_name
& 0xff;
3042 if (c
< 65 || c
> 122 || (c
> 90 && c
< 97))
3043 png_chunk_error(png_ptr
, "invalid chunk type");
3049 /* Combines the row recently read in with the existing pixels in the row. This
3050 * routine takes care of alpha and transparency if requested. This routine also
3051 * handles the two methods of progressive display of interlaced images,
3052 * depending on the 'display' value; if 'display' is true then the whole row
3053 * (dp) is filled from the start by replicating the available pixels. If
3054 * 'display' is false only those pixels present in the pass are filled in.
3057 png_combine_row(png_const_structrp png_ptr
, png_bytep dp
, int display
)
3059 unsigned int pixel_depth
= png_ptr
->transformed_pixel_depth
;
3060 png_const_bytep sp
= png_ptr
->row_buf
+ 1;
3061 png_alloc_size_t row_width
= png_ptr
->width
;
3062 unsigned int pass
= png_ptr
->pass
;
3063 png_bytep end_ptr
= 0;
3064 png_byte end_byte
= 0;
3065 unsigned int end_mask
;
3067 png_debug(1, "in png_combine_row");
3069 /* Added in 1.5.6: it should not be possible to enter this routine until at
3070 * least one row has been read from the PNG data and transformed.
3072 if (pixel_depth
== 0)
3073 png_error(png_ptr
, "internal row logic error");
3075 /* Added in 1.5.4: the pixel depth should match the information returned by
3076 * any call to png_read_update_info at this point. Do not continue if we got
3079 if (png_ptr
->info_rowbytes
!= 0 && png_ptr
->info_rowbytes
!=
3080 PNG_ROWBYTES(pixel_depth
, row_width
))
3081 png_error(png_ptr
, "internal row size calculation error");
3083 /* Don't expect this to ever happen: */
3085 png_error(png_ptr
, "internal row width error");
3087 /* Preserve the last byte in cases where only part of it will be overwritten,
3088 * the multiply below may overflow, we don't care because ANSI-C guarantees
3089 * we get the low bits.
3091 end_mask
= (pixel_depth
* row_width
) & 7;
3094 /* end_ptr == NULL is a flag to say do nothing */
3095 end_ptr
= dp
+ PNG_ROWBYTES(pixel_depth
, row_width
) - 1;
3096 end_byte
= *end_ptr
;
3097 # ifdef PNG_READ_PACKSWAP_SUPPORTED
3098 if ((png_ptr
->transformations
& PNG_PACKSWAP
) != 0)
3099 /* little-endian byte */
3100 end_mask
= 0xff << end_mask
;
3102 else /* big-endian byte */
3104 end_mask
= 0xff >> end_mask
;
3105 /* end_mask is now the bits to *keep* from the destination row */
3108 /* For non-interlaced images this reduces to a memcpy(). A memcpy()
3109 * will also happen if interlacing isn't supported or if the application
3110 * does not call png_set_interlace_handling(). In the latter cases the
3111 * caller just gets a sequence of the unexpanded rows from each interlace
3114 #ifdef PNG_READ_INTERLACING_SUPPORTED
3115 if (png_ptr
->interlaced
!= 0 &&
3116 (png_ptr
->transformations
& PNG_INTERLACE
) != 0 &&
3117 pass
< 6 && (display
== 0 ||
3118 /* The following copies everything for 'display' on passes 0, 2 and 4. */
3119 (display
== 1 && (pass
& 1) != 0)))
3121 /* Narrow images may have no bits in a pass; the caller should handle
3122 * this, but this test is cheap:
3124 if (row_width
<= PNG_PASS_START_COL(pass
))
3127 if (pixel_depth
< 8)
3129 /* For pixel depths up to 4 bpp the 8-pixel mask can be expanded to fit
3130 * into 32 bits, then a single loop over the bytes using the four byte
3131 * values in the 32-bit mask can be used. For the 'display' option the
3132 * expanded mask may also not require any masking within a byte. To
3133 * make this work the PACKSWAP option must be taken into account - it
3134 * simply requires the pixels to be reversed in each byte.
3136 * The 'regular' case requires a mask for each of the first 6 passes,
3137 * the 'display' case does a copy for the even passes in the range
3138 * 0..6. This has already been handled in the test above.
3140 * The masks are arranged as four bytes with the first byte to use in
3141 * the lowest bits (little-endian) regardless of the order (PACKSWAP or
3142 * not) of the pixels in each byte.
3144 * NOTE: the whole of this logic depends on the caller of this function
3145 * only calling it on rows appropriate to the pass. This function only
3146 * understands the 'x' logic; the 'y' logic is handled by the caller.
3148 * The following defines allow generation of compile time constant bit
3149 * masks for each pixel depth and each possibility of swapped or not
3150 * swapped bytes. Pass 'p' is in the range 0..6; 'x', a pixel index,
3151 * is in the range 0..7; and the result is 1 if the pixel is to be
3152 * copied in the pass, 0 if not. 'S' is for the sparkle method, 'B'
3153 * for the block method.
3155 * With some compilers a compile time expression of the general form:
3157 * (shift >= 32) ? (a >> (shift-32)) : (b >> shift)
3159 * Produces warnings with values of 'shift' in the range 33 to 63
3160 * because the right hand side of the ?: expression is evaluated by
3161 * the compiler even though it isn't used. Microsoft Visual C (various
3162 * versions) and the Intel C compiler are known to do this. To avoid
3163 * this the following macros are used in 1.5.6. This is a temporary
3164 * solution to avoid destabilizing the code during the release process.
3166 # if PNG_USE_COMPILE_TIME_MASKS
3167 # define PNG_LSR(x,s) ((x)>>((s) & 0x1f))
3168 # define PNG_LSL(x,s) ((x)<<((s) & 0x1f))
3170 # define PNG_LSR(x,s) ((x)>>(s))
3171 # define PNG_LSL(x,s) ((x)<<(s))
3173 # define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\
3174 PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1)
3175 # define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\
3176 PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1)
3178 /* Return a mask for pass 'p' pixel 'x' at depth 'd'. The mask is
3179 * little endian - the first pixel is at bit 0 - however the extra
3180 * parameter 's' can be set to cause the mask position to be swapped
3181 * within each byte, to match the PNG format. This is done by XOR of
3182 * the shift with 7, 6 or 4 for bit depths 1, 2 and 4.
3184 # define PIXEL_MASK(p,x,d,s) \
3185 (PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0))))
3187 /* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask.
3189 # define S_MASKx(p,x,d,s) (S_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
3190 # define B_MASKx(p,x,d,s) (B_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
3192 /* Combine 8 of these to get the full mask. For the 1-bpp and 2-bpp
3193 * cases the result needs replicating, for the 4-bpp case the above
3194 * generates a full 32 bits.
3196 # define MASK_EXPAND(m,d) ((m)*((d)==1?0x01010101:((d)==2?0x00010001:1)))
3198 # define S_MASK(p,d,s) MASK_EXPAND(S_MASKx(p,0,d,s) + S_MASKx(p,1,d,s) +\
3199 S_MASKx(p,2,d,s) + S_MASKx(p,3,d,s) + S_MASKx(p,4,d,s) +\
3200 S_MASKx(p,5,d,s) + S_MASKx(p,6,d,s) + S_MASKx(p,7,d,s), d)
3202 # define B_MASK(p,d,s) MASK_EXPAND(B_MASKx(p,0,d,s) + B_MASKx(p,1,d,s) +\
3203 B_MASKx(p,2,d,s) + B_MASKx(p,3,d,s) + B_MASKx(p,4,d,s) +\
3204 B_MASKx(p,5,d,s) + B_MASKx(p,6,d,s) + B_MASKx(p,7,d,s), d)
3206 #if PNG_USE_COMPILE_TIME_MASKS
3207 /* Utility macros to construct all the masks for a depth/swap
3208 * combination. The 's' parameter says whether the format is PNG
3209 * (big endian bytes) or not. Only the three odd-numbered passes are
3210 * required for the display/block algorithm.
3212 # define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\
3213 S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) }
3215 # define B_MASKS(d,s) { B_MASK(1,d,s), B_MASK(3,d,s), B_MASK(5,d,s) }
3217 # define DEPTH_INDEX(d) ((d)==1?0:((d)==2?1:2))
3219 /* Hence the pre-compiled masks indexed by PACKSWAP (or not), depth and
3222 static PNG_CONST png_uint_32 row_mask
[2/*PACKSWAP*/][3/*depth*/][6] =
3224 /* Little-endian byte masks for PACKSWAP */
3225 { S_MASKS(1,0), S_MASKS(2,0), S_MASKS(4,0) },
3226 /* Normal (big-endian byte) masks - PNG format */
3227 { S_MASKS(1,1), S_MASKS(2,1), S_MASKS(4,1) }
3230 /* display_mask has only three entries for the odd passes, so index by
3233 static PNG_CONST png_uint_32 display_mask
[2][3][3] =
3235 /* Little-endian byte masks for PACKSWAP */
3236 { B_MASKS(1,0), B_MASKS(2,0), B_MASKS(4,0) },
3237 /* Normal (big-endian byte) masks - PNG format */
3238 { B_MASKS(1,1), B_MASKS(2,1), B_MASKS(4,1) }
3241 # define MASK(pass,depth,display,png)\
3242 ((display)?display_mask[png][DEPTH_INDEX(depth)][pass>>1]:\
3243 row_mask[png][DEPTH_INDEX(depth)][pass])
3245 #else /* !PNG_USE_COMPILE_TIME_MASKS */
3246 /* This is the runtime alternative: it seems unlikely that this will
3247 * ever be either smaller or faster than the compile time approach.
3249 # define MASK(pass,depth,display,png)\
3250 ((display)?B_MASK(pass,depth,png):S_MASK(pass,depth,png))
3251 #endif /* !USE_COMPILE_TIME_MASKS */
3253 /* Use the appropriate mask to copy the required bits. In some cases
3254 * the byte mask will be 0 or 0xff; optimize these cases. row_width is
3255 * the number of pixels, but the code copies bytes, so it is necessary
3256 * to special case the end.
3258 png_uint_32 pixels_per_byte
= 8 / pixel_depth
;
3261 # ifdef PNG_READ_PACKSWAP_SUPPORTED
3262 if ((png_ptr
->transformations
& PNG_PACKSWAP
) != 0)
3263 mask
= MASK(pass
, pixel_depth
, display
, 0);
3267 mask
= MASK(pass
, pixel_depth
, display
, 1);
3273 /* It doesn't matter in the following if png_uint_32 has more than
3274 * 32 bits because the high bits always match those in m<<24; it is,
3275 * however, essential to use OR here, not +, because of this.
3278 mask
= (m
>> 8) | (m
<< 24); /* rotate right to good compilers */
3281 if (m
!= 0) /* something to copy */
3284 *dp
= (png_byte
)((*dp
& ~m
) | (*sp
& m
));
3289 /* NOTE: this may overwrite the last byte with garbage if the image
3290 * is not an exact number of bytes wide; libpng has always done
3293 if (row_width
<= pixels_per_byte
)
3294 break; /* May need to restore part of the last byte */
3296 row_width
-= pixels_per_byte
;
3302 else /* pixel_depth >= 8 */
3304 unsigned int bytes_to_copy
, bytes_to_jump
;
3306 /* Validate the depth - it must be a multiple of 8 */
3307 if (pixel_depth
& 7)
3308 png_error(png_ptr
, "invalid user transform pixel depth");
3310 pixel_depth
>>= 3; /* now in bytes */
3311 row_width
*= pixel_depth
;
3313 /* Regardless of pass number the Adam 7 interlace always results in a
3314 * fixed number of pixels to copy then to skip. There may be a
3315 * different number of pixels to skip at the start though.
3318 unsigned int offset
= PNG_PASS_START_COL(pass
) * pixel_depth
;
3320 row_width
-= offset
;
3325 /* Work out the bytes to copy. */
3328 /* When doing the 'block' algorithm the pixel in the pass gets
3329 * replicated to adjacent pixels. This is why the even (0,2,4,6)
3330 * passes are skipped above - the entire expanded row is copied.
3332 bytes_to_copy
= (1<<((6-pass
)>>1)) * pixel_depth
;
3334 /* But don't allow this number to exceed the actual row width. */
3335 if (bytes_to_copy
> row_width
)
3336 bytes_to_copy
= (unsigned int)/*SAFE*/row_width
;
3339 else /* normal row; Adam7 only ever gives us one pixel to copy. */
3340 bytes_to_copy
= pixel_depth
;
3342 /* In Adam7 there is a constant offset between where the pixels go. */
3343 bytes_to_jump
= PNG_PASS_COL_OFFSET(pass
) * pixel_depth
;
3345 /* And simply copy these bytes. Some optimization is possible here,
3346 * depending on the value of 'bytes_to_copy'. Special case the low
3347 * byte counts, which we know to be frequent.
3349 * Notice that these cases all 'return' rather than 'break' - this
3350 * avoids an unnecessary test on whether to restore the last byte
3353 switch (bytes_to_copy
)
3360 if (row_width
<= bytes_to_jump
)
3363 dp
+= bytes_to_jump
;
3364 sp
+= bytes_to_jump
;
3365 row_width
-= bytes_to_jump
;
3369 /* There is a possibility of a partial copy at the end here; this
3370 * slows the code down somewhat.
3374 dp
[0] = sp
[0], dp
[1] = sp
[1];
3376 if (row_width
<= bytes_to_jump
)
3379 sp
+= bytes_to_jump
;
3380 dp
+= bytes_to_jump
;
3381 row_width
-= bytes_to_jump
;
3383 while (row_width
> 1);
3385 /* And there can only be one byte left at this point: */
3390 /* This can only be the RGB case, so each copy is exactly one
3391 * pixel and it is not necessary to check for a partial copy.
3395 dp
[0] = sp
[0], dp
[1] = sp
[1], dp
[2] = sp
[2];
3397 if (row_width
<= bytes_to_jump
)
3400 sp
+= bytes_to_jump
;
3401 dp
+= bytes_to_jump
;
3402 row_width
-= bytes_to_jump
;
3406 #if PNG_ALIGN_TYPE != PNG_ALIGN_NONE
3407 /* Check for double byte alignment and, if possible, use a
3408 * 16-bit copy. Don't attempt this for narrow images - ones that
3409 * are less than an interlace panel wide. Don't attempt it for
3410 * wide bytes_to_copy either - use the memcpy there.
3412 if (bytes_to_copy
< 16 /*else use memcpy*/ &&
3413 png_isaligned(dp
, png_uint_16
) &&
3414 png_isaligned(sp
, png_uint_16
) &&
3415 bytes_to_copy
% (sizeof (png_uint_16
)) == 0 &&
3416 bytes_to_jump
% (sizeof (png_uint_16
)) == 0)
3418 /* Everything is aligned for png_uint_16 copies, but try for
3419 * png_uint_32 first.
3421 if (png_isaligned(dp
, png_uint_32
) != 0 &&
3422 png_isaligned(sp
, png_uint_32
) != 0 &&
3423 bytes_to_copy
% (sizeof (png_uint_32
)) == 0 &&
3424 bytes_to_jump
% (sizeof (png_uint_32
)) == 0)
3426 png_uint_32p dp32
= png_aligncast(png_uint_32p
,dp
);
3427 png_const_uint_32p sp32
= png_aligncastconst(
3428 png_const_uint_32p
, sp
);
3429 size_t skip
= (bytes_to_jump
-bytes_to_copy
) /
3430 (sizeof (png_uint_32
));
3434 size_t c
= bytes_to_copy
;
3438 c
-= (sizeof (png_uint_32
));
3442 if (row_width
<= bytes_to_jump
)
3447 row_width
-= bytes_to_jump
;
3449 while (bytes_to_copy
<= row_width
);
3451 /* Get to here when the row_width truncates the final copy.
3452 * There will be 1-3 bytes left to copy, so don't try the
3453 * 16-bit loop below.
3455 dp
= (png_bytep
)dp32
;
3456 sp
= (png_const_bytep
)sp32
;
3459 while (--row_width
> 0);
3463 /* Else do it in 16-bit quantities, but only if the size is
3468 png_uint_16p dp16
= png_aligncast(png_uint_16p
, dp
);
3469 png_const_uint_16p sp16
= png_aligncastconst(
3470 png_const_uint_16p
, sp
);
3471 size_t skip
= (bytes_to_jump
-bytes_to_copy
) /
3472 (sizeof (png_uint_16
));
3476 size_t c
= bytes_to_copy
;
3480 c
-= (sizeof (png_uint_16
));
3484 if (row_width
<= bytes_to_jump
)
3489 row_width
-= bytes_to_jump
;
3491 while (bytes_to_copy
<= row_width
);
3493 /* End of row - 1 byte left, bytes_to_copy > row_width: */
3494 dp
= (png_bytep
)dp16
;
3495 sp
= (png_const_bytep
)sp16
;
3498 while (--row_width
> 0);
3502 #endif /* ALIGN_TYPE code */
3504 /* The true default - use a memcpy: */
3507 memcpy(dp
, sp
, bytes_to_copy
);
3509 if (row_width
<= bytes_to_jump
)
3512 sp
+= bytes_to_jump
;
3513 dp
+= bytes_to_jump
;
3514 row_width
-= bytes_to_jump
;
3515 if (bytes_to_copy
> row_width
)
3516 bytes_to_copy
= (unsigned int)/*SAFE*/row_width
;
3521 } /* pixel_depth >= 8 */
3523 /* Here if pixel_depth < 8 to check 'end_ptr' below. */
3526 #endif /* READ_INTERLACING */
3528 /* If here then the switch above wasn't used so just memcpy the whole row
3529 * from the temporary row buffer (notice that this overwrites the end of the
3530 * destination row if it is a partial byte.)
3532 memcpy(dp
, sp
, PNG_ROWBYTES(pixel_depth
, row_width
));
3534 /* Restore the overwritten bits from the last byte if necessary. */
3535 if (end_ptr
!= NULL
)
3536 *end_ptr
= (png_byte
)((end_byte
& end_mask
) | (*end_ptr
& ~end_mask
));
3539 #ifdef PNG_READ_INTERLACING_SUPPORTED
3541 png_do_read_interlace(png_row_infop row_info
, png_bytep row
, int pass
,
3542 png_uint_32 transformations
/* Because these may affect the byte layout */)
3544 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
3545 /* Offset to next interlace block */
3546 static PNG_CONST
int png_pass_inc
[7] = {8, 8, 4, 4, 2, 2, 1};
3548 png_debug(1, "in png_do_read_interlace");
3549 if (row
!= NULL
&& row_info
!= NULL
)
3551 png_uint_32 final_width
;
3553 final_width
= row_info
->width
* png_pass_inc
[pass
];
3555 switch (row_info
->pixel_depth
)
3559 png_bytep sp
= row
+ (png_size_t
)((row_info
->width
- 1) >> 3);
3560 png_bytep dp
= row
+ (png_size_t
)((final_width
- 1) >> 3);
3562 int s_start
, s_end
, s_inc
;
3563 int jstop
= png_pass_inc
[pass
];
3568 #ifdef PNG_READ_PACKSWAP_SUPPORTED
3569 if ((transformations
& PNG_PACKSWAP
) != 0)
3571 sshift
= (int)((row_info
->width
+ 7) & 0x07);
3572 dshift
= (int)((final_width
+ 7) & 0x07);
3581 sshift
= 7 - (int)((row_info
->width
+ 7) & 0x07);
3582 dshift
= 7 - (int)((final_width
+ 7) & 0x07);
3588 for (i
= 0; i
< row_info
->width
; i
++)
3590 v
= (png_byte
)((*sp
>> sshift
) & 0x01);
3591 for (j
= 0; j
< jstop
; j
++)
3593 unsigned int tmp
= *dp
& (0x7f7f >> (7 - dshift
));
3595 *dp
= (png_byte
)(tmp
& 0xff);
3597 if (dshift
== s_end
)
3607 if (sshift
== s_end
)
3621 png_bytep sp
= row
+ (png_uint_32
)((row_info
->width
- 1) >> 2);
3622 png_bytep dp
= row
+ (png_uint_32
)((final_width
- 1) >> 2);
3624 int s_start
, s_end
, s_inc
;
3625 int jstop
= png_pass_inc
[pass
];
3628 #ifdef PNG_READ_PACKSWAP_SUPPORTED
3629 if ((transformations
& PNG_PACKSWAP
) != 0)
3631 sshift
= (int)(((row_info
->width
+ 3) & 0x03) << 1);
3632 dshift
= (int)(((final_width
+ 3) & 0x03) << 1);
3641 sshift
= (int)((3 - ((row_info
->width
+ 3) & 0x03)) << 1);
3642 dshift
= (int)((3 - ((final_width
+ 3) & 0x03)) << 1);
3648 for (i
= 0; i
< row_info
->width
; i
++)
3653 v
= (png_byte
)((*sp
>> sshift
) & 0x03);
3654 for (j
= 0; j
< jstop
; j
++)
3656 unsigned int tmp
= *dp
& (0x3f3f >> (6 - dshift
));
3658 *dp
= (png_byte
)(tmp
& 0xff);
3660 if (dshift
== s_end
)
3670 if (sshift
== s_end
)
3684 png_bytep sp
= row
+ (png_size_t
)((row_info
->width
- 1) >> 1);
3685 png_bytep dp
= row
+ (png_size_t
)((final_width
- 1) >> 1);
3687 int s_start
, s_end
, s_inc
;
3689 int jstop
= png_pass_inc
[pass
];
3691 #ifdef PNG_READ_PACKSWAP_SUPPORTED
3692 if ((transformations
& PNG_PACKSWAP
) != 0)
3694 sshift
= (int)(((row_info
->width
+ 1) & 0x01) << 2);
3695 dshift
= (int)(((final_width
+ 1) & 0x01) << 2);
3704 sshift
= (int)((1 - ((row_info
->width
+ 1) & 0x01)) << 2);
3705 dshift
= (int)((1 - ((final_width
+ 1) & 0x01)) << 2);
3711 for (i
= 0; i
< row_info
->width
; i
++)
3713 png_byte v
= (png_byte
)((*sp
>> sshift
) & 0x0f);
3716 for (j
= 0; j
< jstop
; j
++)
3718 unsigned int tmp
= *dp
& (0xf0f >> (4 - dshift
));
3720 *dp
= (png_byte
)(tmp
& 0xff);
3722 if (dshift
== s_end
)
3732 if (sshift
== s_end
)
3746 png_size_t pixel_bytes
= (row_info
->pixel_depth
>> 3);
3748 png_bytep sp
= row
+ (png_size_t
)(row_info
->width
- 1)
3751 png_bytep dp
= row
+ (png_size_t
)(final_width
- 1) * pixel_bytes
;
3753 int jstop
= png_pass_inc
[pass
];
3756 for (i
= 0; i
< row_info
->width
; i
++)
3758 png_byte v
[8]; /* SAFE; pixel_depth does not exceed 64 */
3761 memcpy(v
, sp
, pixel_bytes
);
3763 for (j
= 0; j
< jstop
; j
++)
3765 memcpy(dp
, v
, pixel_bytes
);
3775 row_info
->width
= final_width
;
3776 row_info
->rowbytes
= PNG_ROWBYTES(row_info
->pixel_depth
, final_width
);
3778 #ifndef PNG_READ_PACKSWAP_SUPPORTED
3779 PNG_UNUSED(transformations
) /* Silence compiler warning */
3782 #endif /* READ_INTERLACING */
3785 png_read_filter_row_sub(png_row_infop row_info
, png_bytep row
,
3786 png_const_bytep prev_row
)
3789 png_size_t istop
= row_info
->rowbytes
;
3790 unsigned int bpp
= (row_info
->pixel_depth
+ 7) >> 3;
3791 png_bytep rp
= row
+ bpp
;
3793 PNG_UNUSED(prev_row
)
3795 for (i
= bpp
; i
< istop
; i
++)
3797 *rp
= (png_byte
)(((int)(*rp
) + (int)(*(rp
-bpp
))) & 0xff);
3803 png_read_filter_row_up(png_row_infop row_info
, png_bytep row
,
3804 png_const_bytep prev_row
)
3807 png_size_t istop
= row_info
->rowbytes
;
3809 png_const_bytep pp
= prev_row
;
3811 for (i
= 0; i
< istop
; i
++)
3813 *rp
= (png_byte
)(((int)(*rp
) + (int)(*pp
++)) & 0xff);
3819 png_read_filter_row_avg(png_row_infop row_info
, png_bytep row
,
3820 png_const_bytep prev_row
)
3824 png_const_bytep pp
= prev_row
;
3825 unsigned int bpp
= (row_info
->pixel_depth
+ 7) >> 3;
3826 png_size_t istop
= row_info
->rowbytes
- bpp
;
3828 for (i
= 0; i
< bpp
; i
++)
3830 *rp
= (png_byte
)(((int)(*rp
) +
3831 ((int)(*pp
++) / 2 )) & 0xff);
3836 for (i
= 0; i
< istop
; i
++)
3838 *rp
= (png_byte
)(((int)(*rp
) +
3839 (int)(*pp
++ + *(rp
-bpp
)) / 2 ) & 0xff);
3846 png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info
, png_bytep row
,
3847 png_const_bytep prev_row
)
3849 png_bytep rp_end
= row
+ row_info
->rowbytes
;
3852 /* First pixel/byte */
3855 *row
++ = (png_byte
)a
;
3858 while (row
< rp_end
)
3860 int b
, pa
, pb
, pc
, p
;
3862 a
&= 0xff; /* From previous iteration or start */
3873 pa
= p
< 0 ? -p
: p
;
3874 pb
= pc
< 0 ? -pc
: pc
;
3875 pc
= (p
+ pc
) < 0 ? -(p
+ pc
) : p
+ pc
;
3878 /* Find the best predictor, the least of pa, pb, pc favoring the earlier
3879 * ones in the case of a tie.
3881 if (pb
< pa
) pa
= pb
, a
= b
;
3884 /* Calculate the current pixel in a, and move the previous row pixel to c
3885 * for the next time round the loop
3889 *row
++ = (png_byte
)a
;
3894 png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info
, png_bytep row
,
3895 png_const_bytep prev_row
)
3897 int bpp
= (row_info
->pixel_depth
+ 7) >> 3;
3898 png_bytep rp_end
= row
+ bpp
;
3900 /* Process the first pixel in the row completely (this is the same as 'up'
3901 * because there is only one candidate predictor for the first row).
3903 while (row
< rp_end
)
3905 int a
= *row
+ *prev_row
++;
3906 *row
++ = (png_byte
)a
;
3910 rp_end
+= row_info
->rowbytes
- bpp
;
3912 while (row
< rp_end
)
3914 int a
, b
, c
, pa
, pb
, pc
, p
;
3916 c
= *(prev_row
- bpp
);
3928 pa
= p
< 0 ? -p
: p
;
3929 pb
= pc
< 0 ? -pc
: pc
;
3930 pc
= (p
+ pc
) < 0 ? -(p
+ pc
) : p
+ pc
;
3933 if (pb
< pa
) pa
= pb
, a
= b
;
3937 *row
++ = (png_byte
)a
;
3942 png_init_filter_functions(png_structrp pp
)
3943 /* This function is called once for every PNG image (except for PNG images
3944 * that only use PNG_FILTER_VALUE_NONE for all rows) to set the
3945 * implementations required to reverse the filtering of PNG rows. Reversing
3946 * the filter is the first transformation performed on the row data. It is
3947 * performed in place, therefore an implementation can be selected based on
3948 * the image pixel format. If the implementation depends on image width then
3949 * take care to ensure that it works correctly if the image is interlaced -
3950 * interlacing causes the actual row width to vary.
3953 unsigned int bpp
= (pp
->pixel_depth
+ 7) >> 3;
3955 pp
->read_filter
[PNG_FILTER_VALUE_SUB
-1] = png_read_filter_row_sub
;
3956 pp
->read_filter
[PNG_FILTER_VALUE_UP
-1] = png_read_filter_row_up
;
3957 pp
->read_filter
[PNG_FILTER_VALUE_AVG
-1] = png_read_filter_row_avg
;
3959 pp
->read_filter
[PNG_FILTER_VALUE_PAETH
-1] =
3960 png_read_filter_row_paeth_1byte_pixel
;
3962 pp
->read_filter
[PNG_FILTER_VALUE_PAETH
-1] =
3963 png_read_filter_row_paeth_multibyte_pixel
;
3965 #ifdef PNG_FILTER_OPTIMIZATIONS
3966 /* To use this define PNG_FILTER_OPTIMIZATIONS as the name of a function to
3967 * call to install hardware optimizations for the above functions; simply
3968 * replace whatever elements of the pp->read_filter[] array with a hardware
3969 * specific (or, for that matter, generic) optimization.
3971 * To see an example of this examine what configure.ac does when
3972 * --enable-arm-neon is specified on the command line.
3974 PNG_FILTER_OPTIMIZATIONS(pp
, bpp
);
3979 png_read_filter_row(png_structrp pp
, png_row_infop row_info
, png_bytep row
,
3980 png_const_bytep prev_row
, int filter
)
3982 /* OPTIMIZATION: DO NOT MODIFY THIS FUNCTION, instead #define
3983 * PNG_FILTER_OPTIMIZATIONS to a function that overrides the generic
3984 * implementations. See png_init_filter_functions above.
3986 if (filter
> PNG_FILTER_VALUE_NONE
&& filter
< PNG_FILTER_VALUE_LAST
)
3988 if (pp
->read_filter
[0] == NULL
)
3989 png_init_filter_functions(pp
);
3991 pp
->read_filter
[filter
-1](row_info
, row
, prev_row
);
3995 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
3997 png_read_IDAT_data(png_structrp png_ptr
, png_bytep output
,
3998 png_alloc_size_t avail_out
)
4000 /* Loop reading IDATs and decompressing the result into output[avail_out] */
4001 png_ptr
->zstream
.next_out
= output
;
4002 png_ptr
->zstream
.avail_out
= 0; /* safety: set below */
4010 png_byte tmpbuf
[PNG_INFLATE_BUF_SIZE
];
4012 if (png_ptr
->zstream
.avail_in
== 0)
4017 while (png_ptr
->idat_size
== 0)
4019 png_crc_finish(png_ptr
, 0);
4021 png_ptr
->idat_size
= png_read_chunk_header(png_ptr
);
4022 /* This is an error even in the 'check' case because the code just
4023 * consumed a non-IDAT header.
4025 if (png_ptr
->chunk_name
!= png_IDAT
)
4026 png_error(png_ptr
, "Not enough image data");
4029 avail_in
= png_ptr
->IDAT_read_size
;
4031 if (avail_in
> png_ptr
->idat_size
)
4032 avail_in
= (uInt
)png_ptr
->idat_size
;
4034 /* A PNG with a gradually increasing IDAT size will defeat this attempt
4035 * to minimize memory usage by causing lots of re-allocs, but
4036 * realistically doing IDAT_read_size re-allocs is not likely to be a
4039 buffer
= png_read_buffer(png_ptr
, avail_in
, 0/*error*/);
4041 png_crc_read(png_ptr
, buffer
, avail_in
);
4042 png_ptr
->idat_size
-= avail_in
;
4044 png_ptr
->zstream
.next_in
= buffer
;
4045 png_ptr
->zstream
.avail_in
= avail_in
;
4048 /* And set up the output side. */
4049 if (output
!= NULL
) /* standard read */
4051 uInt out
= ZLIB_IO_MAX
;
4053 if (out
> avail_out
)
4054 out
= (uInt
)avail_out
;
4057 png_ptr
->zstream
.avail_out
= out
;
4060 else /* after last row, checking for end */
4062 png_ptr
->zstream
.next_out
= tmpbuf
;
4063 png_ptr
->zstream
.avail_out
= (sizeof tmpbuf
);
4066 /* Use NO_FLUSH; this gives zlib the maximum opportunity to optimize the
4067 * process. If the LZ stream is truncated the sequential reader will
4068 * terminally damage the stream, above, by reading the chunk header of the
4069 * following chunk (it then exits with png_error).
4071 * TODO: deal more elegantly with truncated IDAT lists.
4073 ret
= PNG_INFLATE(png_ptr
, Z_NO_FLUSH
);
4075 /* Take the unconsumed output back. */
4077 avail_out
+= png_ptr
->zstream
.avail_out
;
4079 else /* avail_out counts the extra bytes */
4080 avail_out
+= (sizeof tmpbuf
) - png_ptr
->zstream
.avail_out
;
4082 png_ptr
->zstream
.avail_out
= 0;
4084 if (ret
== Z_STREAM_END
)
4086 /* Do this for safety; we won't read any more into this row. */
4087 png_ptr
->zstream
.next_out
= NULL
;
4089 png_ptr
->mode
|= PNG_AFTER_IDAT
;
4090 png_ptr
->flags
|= PNG_FLAG_ZSTREAM_ENDED
;
4092 if (png_ptr
->zstream
.avail_in
> 0 || png_ptr
->idat_size
> 0)
4093 png_chunk_benign_error(png_ptr
, "Extra compressed data");
4099 png_zstream_error(png_ptr
, ret
);
4102 png_chunk_error(png_ptr
, png_ptr
->zstream
.msg
);
4106 png_chunk_benign_error(png_ptr
, png_ptr
->zstream
.msg
);
4110 } while (avail_out
> 0);
4114 /* The stream ended before the image; this is the same as too few IDATs so
4115 * should be handled the same way.
4118 png_error(png_ptr
, "Not enough image data");
4120 else /* the deflate stream contained extra data */
4121 png_chunk_benign_error(png_ptr
, "Too much image data");
4126 png_read_finish_IDAT(png_structrp png_ptr
)
4128 /* We don't need any more data and the stream should have ended, however the
4129 * LZ end code may actually not have been processed. In this case we must
4130 * read it otherwise stray unread IDAT data or, more likely, an IDAT chunk
4131 * may still remain to be consumed.
4133 if ((png_ptr
->flags
& PNG_FLAG_ZSTREAM_ENDED
) == 0)
4135 /* The NULL causes png_read_IDAT_data to swallow any remaining bytes in
4136 * the compressed stream, but the stream may be damaged too, so even after
4137 * this call we may need to terminate the zstream ownership.
4139 png_read_IDAT_data(png_ptr
, NULL
, 0);
4140 png_ptr
->zstream
.next_out
= NULL
; /* safety */
4142 /* Now clear everything out for safety; the following may not have been
4145 if ((png_ptr
->flags
& PNG_FLAG_ZSTREAM_ENDED
) == 0)
4147 png_ptr
->mode
|= PNG_AFTER_IDAT
;
4148 png_ptr
->flags
|= PNG_FLAG_ZSTREAM_ENDED
;
4152 /* If the zstream has not been released do it now *and* terminate the reading
4153 * of the final IDAT chunk.
4155 if (png_ptr
->zowner
== png_IDAT
)
4157 /* Always do this; the pointers otherwise point into the read buffer. */
4158 png_ptr
->zstream
.next_in
= NULL
;
4159 png_ptr
->zstream
.avail_in
= 0;
4161 /* Now we no longer own the zstream. */
4162 png_ptr
->zowner
= 0;
4164 /* The slightly weird semantics of the sequential IDAT reading is that we
4165 * are always in or at the end of an IDAT chunk, so we always need to do a
4166 * crc_finish here. If idat_size is non-zero we also need to read the
4167 * spurious bytes at the end of the chunk now.
4169 (void)png_crc_finish(png_ptr
, png_ptr
->idat_size
);
4174 png_read_finish_row(png_structrp png_ptr
)
4176 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
4178 /* Start of interlace block */
4179 static PNG_CONST png_byte png_pass_start
[7] = {0, 4, 0, 2, 0, 1, 0};
4181 /* Offset to next interlace block */
4182 static PNG_CONST png_byte png_pass_inc
[7] = {8, 8, 4, 4, 2, 2, 1};
4184 /* Start of interlace block in the y direction */
4185 static PNG_CONST png_byte png_pass_ystart
[7] = {0, 0, 4, 0, 2, 0, 1};
4187 /* Offset to next interlace block in the y direction */
4188 static PNG_CONST png_byte png_pass_yinc
[7] = {8, 8, 8, 4, 4, 2, 2};
4190 png_debug(1, "in png_read_finish_row");
4191 png_ptr
->row_number
++;
4192 if (png_ptr
->row_number
< png_ptr
->num_rows
)
4195 if (png_ptr
->interlaced
!= 0)
4197 png_ptr
->row_number
= 0;
4199 /* TO DO: don't do this if prev_row isn't needed (requires
4200 * read-ahead of the next row's filter byte.
4202 memset(png_ptr
->prev_row
, 0, png_ptr
->rowbytes
+ 1);
4208 if (png_ptr
->pass
>= 7)
4211 png_ptr
->iwidth
= (png_ptr
->width
+
4212 png_pass_inc
[png_ptr
->pass
] - 1 -
4213 png_pass_start
[png_ptr
->pass
]) /
4214 png_pass_inc
[png_ptr
->pass
];
4216 if ((png_ptr
->transformations
& PNG_INTERLACE
) == 0)
4218 png_ptr
->num_rows
= (png_ptr
->height
+
4219 png_pass_yinc
[png_ptr
->pass
] - 1 -
4220 png_pass_ystart
[png_ptr
->pass
]) /
4221 png_pass_yinc
[png_ptr
->pass
];
4224 else /* if (png_ptr->transformations & PNG_INTERLACE) */
4225 break; /* libpng deinterlacing sees every row */
4227 } while (png_ptr
->num_rows
== 0 || png_ptr
->iwidth
== 0);
4229 if (png_ptr
->pass
< 7)
4233 /* Here after at the end of the last row of the last pass. */
4234 png_read_finish_IDAT(png_ptr
);
4236 #endif /* SEQUENTIAL_READ */
4239 png_read_start_row(png_structrp png_ptr
)
4241 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
4243 /* Start of interlace block */
4244 static PNG_CONST png_byte png_pass_start
[7] = {0, 4, 0, 2, 0, 1, 0};
4246 /* Offset to next interlace block */
4247 static PNG_CONST png_byte png_pass_inc
[7] = {8, 8, 4, 4, 2, 2, 1};
4249 /* Start of interlace block in the y direction */
4250 static PNG_CONST png_byte png_pass_ystart
[7] = {0, 0, 4, 0, 2, 0, 1};
4252 /* Offset to next interlace block in the y direction */
4253 static PNG_CONST png_byte png_pass_yinc
[7] = {8, 8, 8, 4, 4, 2, 2};
4255 int max_pixel_depth
;
4256 png_size_t row_bytes
;
4258 png_debug(1, "in png_read_start_row");
4260 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
4261 png_init_read_transformations(png_ptr
);
4263 if (png_ptr
->interlaced
!= 0)
4265 if ((png_ptr
->transformations
& PNG_INTERLACE
) == 0)
4266 png_ptr
->num_rows
= (png_ptr
->height
+ png_pass_yinc
[0] - 1 -
4267 png_pass_ystart
[0]) / png_pass_yinc
[0];
4270 png_ptr
->num_rows
= png_ptr
->height
;
4272 png_ptr
->iwidth
= (png_ptr
->width
+
4273 png_pass_inc
[png_ptr
->pass
] - 1 -
4274 png_pass_start
[png_ptr
->pass
]) /
4275 png_pass_inc
[png_ptr
->pass
];
4280 png_ptr
->num_rows
= png_ptr
->height
;
4281 png_ptr
->iwidth
= png_ptr
->width
;
4284 max_pixel_depth
= png_ptr
->pixel_depth
;
4286 /* WARNING: * png_read_transform_info (pngrtran.c) performs a simpler set of
4287 * calculations to calculate the final pixel depth, then
4288 * png_do_read_transforms actually does the transforms. This means that the
4289 * code which effectively calculates this value is actually repeated in three
4290 * separate places. They must all match. Innocent changes to the order of
4291 * transformations can and will break libpng in a way that causes memory
4296 #ifdef PNG_READ_PACK_SUPPORTED
4297 if ((png_ptr
->transformations
& PNG_PACK
) != 0 && png_ptr
->bit_depth
< 8)
4298 max_pixel_depth
= 8;
4301 #ifdef PNG_READ_EXPAND_SUPPORTED
4302 if ((png_ptr
->transformations
& PNG_EXPAND
) != 0)
4304 if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
4306 if (png_ptr
->num_trans
!= 0)
4307 max_pixel_depth
= 32;
4310 max_pixel_depth
= 24;
4313 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_GRAY
)
4315 if (max_pixel_depth
< 8)
4316 max_pixel_depth
= 8;
4318 if (png_ptr
->num_trans
!= 0)
4319 max_pixel_depth
*= 2;
4322 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_RGB
)
4324 if (png_ptr
->num_trans
!= 0)
4326 max_pixel_depth
*= 4;
4327 max_pixel_depth
/= 3;
4333 #ifdef PNG_READ_EXPAND_16_SUPPORTED
4334 if ((png_ptr
->transformations
& PNG_EXPAND_16
) != 0)
4336 # ifdef PNG_READ_EXPAND_SUPPORTED
4337 /* In fact it is an error if it isn't supported, but checking is
4340 if ((png_ptr
->transformations
& PNG_EXPAND
) != 0)
4342 if (png_ptr
->bit_depth
< 16)
4343 max_pixel_depth
*= 2;
4347 png_ptr
->transformations
&= ~PNG_EXPAND_16
;
4351 #ifdef PNG_READ_FILLER_SUPPORTED
4352 if ((png_ptr
->transformations
& (PNG_FILLER
)) != 0)
4354 if (png_ptr
->color_type
== PNG_COLOR_TYPE_GRAY
)
4356 if (max_pixel_depth
<= 8)
4357 max_pixel_depth
= 16;
4360 max_pixel_depth
= 32;
4363 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_RGB
||
4364 png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
4366 if (max_pixel_depth
<= 32)
4367 max_pixel_depth
= 32;
4370 max_pixel_depth
= 64;
4375 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
4376 if ((png_ptr
->transformations
& PNG_GRAY_TO_RGB
) != 0)
4379 #ifdef PNG_READ_EXPAND_SUPPORTED
4380 (png_ptr
->num_trans
!= 0 &&
4381 (png_ptr
->transformations
& PNG_EXPAND
) != 0) ||
4383 #ifdef PNG_READ_FILLER_SUPPORTED
4384 (png_ptr
->transformations
& (PNG_FILLER
)) != 0 ||
4386 png_ptr
->color_type
== PNG_COLOR_TYPE_GRAY_ALPHA
)
4388 if (max_pixel_depth
<= 16)
4389 max_pixel_depth
= 32;
4392 max_pixel_depth
= 64;
4397 if (max_pixel_depth
<= 8)
4399 if (png_ptr
->color_type
== PNG_COLOR_TYPE_RGB_ALPHA
)
4400 max_pixel_depth
= 32;
4403 max_pixel_depth
= 24;
4406 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_RGB_ALPHA
)
4407 max_pixel_depth
= 64;
4410 max_pixel_depth
= 48;
4415 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) && \
4416 defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
4417 if ((png_ptr
->transformations
& PNG_USER_TRANSFORM
) != 0)
4419 int user_pixel_depth
= png_ptr
->user_transform_depth
*
4420 png_ptr
->user_transform_channels
;
4422 if (user_pixel_depth
> max_pixel_depth
)
4423 max_pixel_depth
= user_pixel_depth
;
4427 /* This value is stored in png_struct and double checked in the row read
4430 png_ptr
->maximum_pixel_depth
= (png_byte
)max_pixel_depth
;
4431 png_ptr
->transformed_pixel_depth
= 0; /* calculated on demand */
4433 /* Align the width on the next larger 8 pixels. Mainly used
4436 row_bytes
= ((png_ptr
->width
+ 7) & ~((png_uint_32
)7));
4437 /* Calculate the maximum bytes needed, adding a byte and a pixel
4440 row_bytes
= PNG_ROWBYTES(max_pixel_depth
, row_bytes
) +
4441 1 + ((max_pixel_depth
+ 7) >> 3);
4443 #ifdef PNG_MAX_MALLOC_64K
4444 if (row_bytes
> (png_uint_32
)65536L)
4445 png_error(png_ptr
, "This image requires a row greater than 64KB");
4448 if (row_bytes
+ 48 > png_ptr
->old_big_row_buf_size
)
4450 png_free(png_ptr
, png_ptr
->big_row_buf
);
4451 png_free(png_ptr
, png_ptr
->big_prev_row
);
4453 if (png_ptr
->interlaced
!= 0)
4454 png_ptr
->big_row_buf
= (png_bytep
)png_calloc(png_ptr
,
4458 png_ptr
->big_row_buf
= (png_bytep
)png_malloc(png_ptr
, row_bytes
+ 48);
4460 png_ptr
->big_prev_row
= (png_bytep
)png_malloc(png_ptr
, row_bytes
+ 48);
4462 #ifdef PNG_ALIGNED_MEMORY_SUPPORTED
4463 /* Use 16-byte aligned memory for row_buf with at least 16 bytes
4464 * of padding before and after row_buf; treat prev_row similarly.
4465 * NOTE: the alignment is to the start of the pixels, one beyond the start
4466 * of the buffer, because of the filter byte. Prior to libpng 1.5.6 this
4467 * was incorrect; the filter byte was aligned, which had the exact
4468 * opposite effect of that intended.
4471 png_bytep temp
= png_ptr
->big_row_buf
+ 32;
4472 int extra
= (int)((temp
- (png_bytep
)0) & 0x0f);
4473 png_ptr
->row_buf
= temp
- extra
- 1/*filter byte*/;
4475 temp
= png_ptr
->big_prev_row
+ 32;
4476 extra
= (int)((temp
- (png_bytep
)0) & 0x0f);
4477 png_ptr
->prev_row
= temp
- extra
- 1/*filter byte*/;
4481 /* Use 31 bytes of padding before and 17 bytes after row_buf. */
4482 png_ptr
->row_buf
= png_ptr
->big_row_buf
+ 31;
4483 png_ptr
->prev_row
= png_ptr
->big_prev_row
+ 31;
4485 png_ptr
->old_big_row_buf_size
= row_bytes
+ 48;
4488 #ifdef PNG_MAX_MALLOC_64K
4489 if (png_ptr
->rowbytes
> 65535)
4490 png_error(png_ptr
, "This image requires a row greater than 64KB");
4493 if (png_ptr
->rowbytes
> (PNG_SIZE_MAX
- 1))
4494 png_error(png_ptr
, "Row has too many bytes to allocate in memory");
4496 memset(png_ptr
->prev_row
, 0, png_ptr
->rowbytes
+ 1);
4498 png_debug1(3, "width = %u,", png_ptr
->width
);
4499 png_debug1(3, "height = %u,", png_ptr
->height
);
4500 png_debug1(3, "iwidth = %u,", png_ptr
->iwidth
);
4501 png_debug1(3, "num_rows = %u,", png_ptr
->num_rows
);
4502 png_debug1(3, "rowbytes = %lu,", (unsigned long)png_ptr
->rowbytes
);
4503 png_debug1(3, "irowbytes = %lu",
4504 (unsigned long)PNG_ROWBYTES(png_ptr
->pixel_depth
, png_ptr
->iwidth
) + 1);
4506 /* The sequential reader needs a buffer for IDAT, but the progressive reader
4507 * does not, so free the read buffer now regardless; the sequential reader
4508 * reallocates it on demand.
4510 if (png_ptr
->read_buffer
!= 0)
4512 png_bytep buffer
= png_ptr
->read_buffer
;
4514 png_ptr
->read_buffer_size
= 0;
4515 png_ptr
->read_buffer
= NULL
;
4516 png_free(png_ptr
, buffer
);
4519 /* Finally claim the zstream for the inflate of the IDAT data, use the bits
4520 * value from the stream (note that this will result in a fatal error if the
4521 * IDAT stream has a bogus deflate header window_bits value, but this should
4522 * not be happening any longer!)
4524 if (png_inflate_claim(png_ptr
, png_IDAT
) != Z_OK
)
4525 png_error(png_ptr
, png_ptr
->zstream
.msg
);
4527 png_ptr
->flags
|= PNG_FLAG_ROW_INIT
;