2 /* pngrutil.c - utilities to read a PNG file
4 * Copyright (c) 2018-2024 Cosmin Truta
5 * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
6 * Copyright (c) 1996-1997 Andreas Dilger
7 * 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 */
89 return (png_int_32
)uval
;
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 accommodate 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 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) != 0)
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 chunk typeid = 0x%lx, 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 /* Check for too-large chunk length */
185 png_check_chunk_length(png_ptr
, length
);
187 #ifdef PNG_IO_STATE_SUPPORTED
188 png_ptr
->io_state
= PNG_IO_READING
| PNG_IO_CHUNK_DATA
;
194 /* Read data, and (optionally) run it through the CRC. */
196 png_crc_read(png_structrp png_ptr
, png_bytep buf
, png_uint_32 length
)
201 png_read_data(png_ptr
, buf
, length
);
202 png_calculate_crc(png_ptr
, buf
, length
);
205 /* Optionally skip data and then check the CRC. Depending on whether we
206 * are reading an ancillary or critical chunk, and how the program has set
207 * things up, we may calculate the CRC on the data and print a message.
208 * Returns '1' if there was a CRC error, '0' otherwise.
211 png_crc_finish(png_structrp png_ptr
, png_uint_32 skip
)
213 /* The size of the local buffer for inflate is a good guess as to a
214 * reasonable size to use for buffering reads from the application.
219 png_byte tmpbuf
[PNG_INFLATE_BUF_SIZE
];
221 len
= (sizeof tmpbuf
);
226 png_crc_read(png_ptr
, tmpbuf
, len
);
229 if (png_crc_error(png_ptr
) != 0)
231 if (PNG_CHUNK_ANCILLARY(png_ptr
->chunk_name
) != 0 ?
232 (png_ptr
->flags
& PNG_FLAG_CRC_ANCILLARY_NOWARN
) == 0 :
233 (png_ptr
->flags
& PNG_FLAG_CRC_CRITICAL_USE
) != 0)
235 png_chunk_warning(png_ptr
, "CRC error");
239 png_chunk_error(png_ptr
, "CRC error");
247 /* Compare the CRC stored in the PNG file with that calculated by libpng from
248 * the data it has read thus far.
251 png_crc_error(png_structrp png_ptr
)
253 png_byte crc_bytes
[4];
257 if (PNG_CHUNK_ANCILLARY(png_ptr
->chunk_name
) != 0)
259 if ((png_ptr
->flags
& PNG_FLAG_CRC_ANCILLARY_MASK
) ==
260 (PNG_FLAG_CRC_ANCILLARY_USE
| PNG_FLAG_CRC_ANCILLARY_NOWARN
))
266 if ((png_ptr
->flags
& PNG_FLAG_CRC_CRITICAL_IGNORE
) != 0)
270 #ifdef PNG_IO_STATE_SUPPORTED
271 png_ptr
->io_state
= PNG_IO_READING
| PNG_IO_CHUNK_CRC
;
274 /* The chunk CRC must be serialized in a single I/O call. */
275 png_read_data(png_ptr
, crc_bytes
, 4);
279 crc
= png_get_uint_32(crc_bytes
);
280 return crc
!= png_ptr
->crc
;
287 #if defined(PNG_READ_iCCP_SUPPORTED) || defined(PNG_READ_iTXt_SUPPORTED) ||\
288 defined(PNG_READ_pCAL_SUPPORTED) || defined(PNG_READ_sCAL_SUPPORTED) ||\
289 defined(PNG_READ_sPLT_SUPPORTED) || defined(PNG_READ_tEXt_SUPPORTED) ||\
290 defined(PNG_READ_zTXt_SUPPORTED) || defined(PNG_SEQUENTIAL_READ_SUPPORTED)
291 /* Manage the read buffer; this simply reallocates the buffer if it is not small
292 * enough (or if it is not allocated). The routine returns a pointer to the
293 * buffer; if an error occurs and 'warn' is set the routine returns NULL, else
294 * it will call png_error (via png_malloc) on failure. (warn == 2 means
298 png_read_buffer(png_structrp png_ptr
, png_alloc_size_t new_size
, int warn
)
300 png_bytep buffer
= png_ptr
->read_buffer
;
302 if (buffer
!= NULL
&& new_size
> png_ptr
->read_buffer_size
)
304 png_ptr
->read_buffer
= NULL
;
305 png_ptr
->read_buffer_size
= 0;
306 png_free(png_ptr
, buffer
);
312 buffer
= png_voidcast(png_bytep
, png_malloc_base(png_ptr
, new_size
));
316 memset(buffer
, 0, new_size
); /* just in case */
317 png_ptr
->read_buffer
= buffer
;
318 png_ptr
->read_buffer_size
= new_size
;
321 else if (warn
< 2) /* else silent */
324 png_chunk_warning(png_ptr
, "insufficient memory to read chunk");
327 png_chunk_error(png_ptr
, "insufficient memory to read chunk");
333 #endif /* READ_iCCP|iTXt|pCAL|sCAL|sPLT|tEXt|zTXt|SEQUENTIAL_READ */
335 /* png_inflate_claim: claim the zstream for some nefarious purpose that involves
336 * decompression. Returns Z_OK on success, else a zlib error code. It checks
337 * the owner but, in final release builds, just issues a warning if some other
338 * chunk apparently owns the stream. Prior to release it does a png_error.
341 png_inflate_claim(png_structrp png_ptr
, png_uint_32 owner
)
343 if (png_ptr
->zowner
!= 0)
347 PNG_STRING_FROM_CHUNK(msg
, png_ptr
->zowner
);
348 /* So the message that results is "<chunk> using zstream"; this is an
349 * internal error, but is very useful for debugging. i18n requirements
352 (void)png_safecat(msg
, (sizeof msg
), 4, " using zstream");
353 #if PNG_RELEASE_BUILD
354 png_chunk_warning(png_ptr
, msg
);
357 png_chunk_error(png_ptr
, msg
);
361 /* Implementation note: unlike 'png_deflate_claim' this internal function
362 * does not take the size of the data as an argument. Some efficiency could
363 * be gained by using this when it is known *if* the zlib stream itself does
364 * not record the number; however, this is an illusion: the original writer
365 * of the PNG may have selected a lower window size, and we really must
366 * follow that because, for systems with with limited capabilities, we
367 * would otherwise reject the application's attempts to use a smaller window
368 * size (zlib doesn't have an interface to say "this or lower"!).
370 * inflateReset2 was added to zlib 1.2.4; before this the window could not be
371 * reset, therefore it is necessary to always allocate the maximum window
372 * size with earlier zlibs just in case later compressed chunks need it.
375 int ret
; /* zlib return code */
376 #if ZLIB_VERNUM >= 0x1240
379 # if defined(PNG_SET_OPTION_SUPPORTED) && defined(PNG_MAXIMUM_INFLATE_WINDOW)
380 if (((png_ptr
->options
>> PNG_MAXIMUM_INFLATE_WINDOW
) & 3) ==
384 png_ptr
->zstream_start
= 0; /* fixed window size */
389 png_ptr
->zstream_start
= 1;
393 #endif /* ZLIB_VERNUM >= 0x1240 */
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 ZLIB_VERNUM >= 0x1240
406 ret
= inflateReset2(&png_ptr
->zstream
, window_bits
);
408 ret
= inflateReset(&png_ptr
->zstream
);
414 #if ZLIB_VERNUM >= 0x1240
415 ret
= inflateInit2(&png_ptr
->zstream
, window_bits
);
417 ret
= inflateInit(&png_ptr
->zstream
);
421 png_ptr
->flags
|= PNG_FLAG_ZSTREAM_INITIALIZED
;
424 #ifdef PNG_DISABLE_ADLER32_CHECK_SUPPORTED
425 if (((png_ptr
->options
>> PNG_IGNORE_ADLER32
) & 3) == PNG_OPTION_ON
)
426 /* Turn off validation of the ADLER32 checksum in IDAT chunks */
427 ret
= inflateValidate(&png_ptr
->zstream
, 0);
431 png_ptr
->zowner
= owner
;
434 png_zstream_error(png_ptr
, ret
);
444 #if ZLIB_VERNUM >= 0x1240
445 /* Handle the start of the inflate stream if we called inflateInit2(strm,0);
446 * in this case some zlib versions skip validation of the CINFO field and, in
447 * certain circumstances, libpng may end up displaying an invalid image, in
448 * contrast to implementations that call zlib in the normal way (e.g. libpng
452 png_zlib_inflate(png_structrp png_ptr
, int flush
)
454 if (png_ptr
->zstream_start
&& png_ptr
->zstream
.avail_in
> 0)
456 if ((*png_ptr
->zstream
.next_in
>> 4) > 7)
458 png_ptr
->zstream
.msg
= "invalid window size (libpng)";
462 png_ptr
->zstream_start
= 0;
465 return inflate(&png_ptr
->zstream
, flush
);
467 #endif /* Zlib >= 1.2.4 */
469 #ifdef PNG_READ_COMPRESSED_TEXT_SUPPORTED
470 #if defined(PNG_READ_zTXt_SUPPORTED) || defined (PNG_READ_iTXt_SUPPORTED)
471 /* png_inflate now returns zlib error codes including Z_OK and Z_STREAM_END to
472 * allow the caller to do multiple calls if required. If the 'finish' flag is
473 * set Z_FINISH will be passed to the final inflate() call and Z_STREAM_END must
474 * be returned or there has been a problem, otherwise Z_SYNC_FLUSH is used and
475 * Z_OK or Z_STREAM_END will be returned on success.
477 * The input and output sizes are updated to the actual amounts of data consumed
478 * or written, not the amount available (as in a z_stream). The data pointers
479 * are not changed, so the next input is (data+input_size) and the next
480 * available output is (output+output_size).
483 png_inflate(png_structrp png_ptr
, png_uint_32 owner
, int finish
,
484 /* INPUT: */ png_const_bytep input
, png_uint_32p input_size_ptr
,
485 /* OUTPUT: */ png_bytep output
, png_alloc_size_t
*output_size_ptr
)
487 if (png_ptr
->zowner
== owner
) /* Else not claimed */
490 png_alloc_size_t avail_out
= *output_size_ptr
;
491 png_uint_32 avail_in
= *input_size_ptr
;
493 /* zlib can't necessarily handle more than 65535 bytes at once (i.e. it
494 * can't even necessarily handle 65536 bytes) because the type uInt is
495 * "16 bits or more". Consequently it is necessary to chunk the input to
496 * zlib. This code uses ZLIB_IO_MAX, from pngpriv.h, as the maximum (the
497 * maximum value that can be stored in a uInt.) It is possible to set
498 * ZLIB_IO_MAX to a lower value in pngpriv.h and this may sometimes have
499 * a performance advantage, because it reduces the amount of data accessed
500 * at each step and that may give the OS more time to page it in.
502 png_ptr
->zstream
.next_in
= PNGZ_INPUT_CAST(input
);
503 /* avail_in and avail_out are set below from 'size' */
504 png_ptr
->zstream
.avail_in
= 0;
505 png_ptr
->zstream
.avail_out
= 0;
507 /* Read directly into the output if it is available (this is set to
508 * a local buffer below if output is NULL).
511 png_ptr
->zstream
.next_out
= output
;
516 Byte local_buffer
[PNG_INFLATE_BUF_SIZE
];
518 /* zlib INPUT BUFFER */
519 /* The setting of 'avail_in' used to be outside the loop; by setting it
520 * inside it is possible to chunk the input to zlib and simply rely on
521 * zlib to advance the 'next_in' pointer. This allows arbitrary
522 * amounts of data to be passed through zlib at the unavoidable cost of
523 * requiring a window save (memcpy of up to 32768 output bytes)
524 * every ZLIB_IO_MAX input bytes.
526 avail_in
+= png_ptr
->zstream
.avail_in
; /* not consumed last time */
530 if (avail_in
< avail
)
531 avail
= (uInt
)avail_in
; /* safe: < than ZLIB_IO_MAX */
534 png_ptr
->zstream
.avail_in
= avail
;
536 /* zlib OUTPUT BUFFER */
537 avail_out
+= png_ptr
->zstream
.avail_out
; /* not written last time */
539 avail
= ZLIB_IO_MAX
; /* maximum zlib can process */
543 /* Reset the output buffer each time round if output is NULL and
544 * make available the full buffer, up to 'remaining_space'
546 png_ptr
->zstream
.next_out
= local_buffer
;
547 if ((sizeof local_buffer
) < avail
)
548 avail
= (sizeof local_buffer
);
551 if (avail_out
< avail
)
552 avail
= (uInt
)avail_out
; /* safe: < ZLIB_IO_MAX */
554 png_ptr
->zstream
.avail_out
= avail
;
557 /* zlib inflate call */
558 /* In fact 'avail_out' may be 0 at this point, that happens at the end
559 * of the read when the final LZ end code was not passed at the end of
560 * the previous chunk of input data. Tell zlib if we have reached the
561 * end of the output buffer.
563 ret
= PNG_INFLATE(png_ptr
, avail_out
> 0 ? Z_NO_FLUSH
:
564 (finish
? Z_FINISH
: Z_SYNC_FLUSH
));
565 } while (ret
== Z_OK
);
567 /* For safety kill the local buffer pointer now */
569 png_ptr
->zstream
.next_out
= NULL
;
571 /* Claw back the 'size' and 'remaining_space' byte counts. */
572 avail_in
+= png_ptr
->zstream
.avail_in
;
573 avail_out
+= png_ptr
->zstream
.avail_out
;
575 /* Update the input and output sizes; the updated values are the amount
576 * consumed or written, effectively the inverse of what zlib uses.
579 *output_size_ptr
-= avail_out
;
582 *input_size_ptr
-= avail_in
;
584 /* Ensure png_ptr->zstream.msg is set (even in the success case!) */
585 png_zstream_error(png_ptr
, ret
);
591 /* This is a bad internal error. The recovery assigns to the zstream msg
592 * pointer, which is not owned by the caller, but this is safe; it's only
595 png_ptr
->zstream
.msg
= PNGZ_MSG_CAST("zstream unclaimed");
596 return Z_STREAM_ERROR
;
601 * Decompress trailing data in a chunk. The assumption is that read_buffer
602 * points at an allocated area holding the contents of a chunk with a
603 * trailing compressed part. What we get back is an allocated area
604 * holding the original prefix part and an uncompressed version of the
605 * trailing part (the malloc area passed in is freed).
608 png_decompress_chunk(png_structrp png_ptr
,
609 png_uint_32 chunklength
, png_uint_32 prefix_size
,
610 png_alloc_size_t
*newlength
/* must be initialized to the maximum! */,
611 int terminate
/*add a '\0' to the end of the uncompressed data*/)
613 /* TODO: implement different limits for different types of chunk.
615 * The caller supplies *newlength set to the maximum length of the
616 * uncompressed data, but this routine allocates space for the prefix and
617 * maybe a '\0' terminator too. We have to assume that 'prefix_size' is
618 * limited only by the maximum chunk size.
620 png_alloc_size_t limit
= PNG_SIZE_MAX
;
622 # ifdef PNG_SET_USER_LIMITS_SUPPORTED
623 if (png_ptr
->user_chunk_malloc_max
> 0 &&
624 png_ptr
->user_chunk_malloc_max
< limit
)
625 limit
= png_ptr
->user_chunk_malloc_max
;
626 # elif PNG_USER_CHUNK_MALLOC_MAX > 0
627 if (PNG_USER_CHUNK_MALLOC_MAX
< limit
)
628 limit
= PNG_USER_CHUNK_MALLOC_MAX
;
631 if (limit
>= prefix_size
+ (terminate
!= 0))
635 limit
-= prefix_size
+ (terminate
!= 0);
637 if (limit
< *newlength
)
640 /* Now try to claim the stream. */
641 ret
= png_inflate_claim(png_ptr
, png_ptr
->chunk_name
);
645 png_uint_32 lzsize
= chunklength
- prefix_size
;
647 ret
= png_inflate(png_ptr
, png_ptr
->chunk_name
, 1/*finish*/,
648 /* input: */ png_ptr
->read_buffer
+ prefix_size
, &lzsize
,
649 /* output: */ NULL
, newlength
);
651 if (ret
== Z_STREAM_END
)
653 /* Use 'inflateReset' here, not 'inflateReset2' because this
654 * preserves the previously decided window size (otherwise it would
655 * be necessary to store the previous window size.) In practice
656 * this doesn't matter anyway, because png_inflate will call inflate
657 * with Z_FINISH in almost all cases, so the window will not be
660 if (inflateReset(&png_ptr
->zstream
) == Z_OK
)
662 /* Because of the limit checks above we know that the new,
663 * expanded, size will fit in a size_t (let alone an
664 * png_alloc_size_t). Use png_malloc_base here to avoid an
667 png_alloc_size_t new_size
= *newlength
;
668 png_alloc_size_t buffer_size
= prefix_size
+ new_size
+
670 png_bytep text
= png_voidcast(png_bytep
, png_malloc_base(png_ptr
,
675 memset(text
, 0, buffer_size
);
677 ret
= png_inflate(png_ptr
, png_ptr
->chunk_name
, 1/*finish*/,
678 png_ptr
->read_buffer
+ prefix_size
, &lzsize
,
679 text
+ prefix_size
, newlength
);
681 if (ret
== Z_STREAM_END
)
683 if (new_size
== *newlength
)
686 text
[prefix_size
+ *newlength
] = 0;
689 memcpy(text
, png_ptr
->read_buffer
, prefix_size
);
692 png_bytep old_ptr
= png_ptr
->read_buffer
;
694 png_ptr
->read_buffer
= text
;
695 png_ptr
->read_buffer_size
= buffer_size
;
696 text
= old_ptr
; /* freed below */
702 /* The size changed on the second read, there can be no
703 * guarantee that anything is correct at this point.
704 * The 'msg' pointer has been set to "unexpected end of
705 * LZ stream", which is fine, but return an error code
706 * that the caller won't accept.
708 ret
= PNG_UNEXPECTED_ZLIB_RETURN
;
712 else if (ret
== Z_OK
)
713 ret
= PNG_UNEXPECTED_ZLIB_RETURN
; /* for safety */
715 /* Free the text pointer (this is the old read_buffer on
718 png_free(png_ptr
, text
);
720 /* This really is very benign, but it's still an error because
721 * the extra space may otherwise be used as a Trojan Horse.
723 if (ret
== Z_STREAM_END
&&
724 chunklength
- prefix_size
!= lzsize
)
725 png_chunk_benign_error(png_ptr
, "extra compressed data");
730 /* Out of memory allocating the buffer */
732 png_zstream_error(png_ptr
, Z_MEM_ERROR
);
738 /* inflateReset failed, store the error message */
739 png_zstream_error(png_ptr
, ret
);
740 ret
= PNG_UNEXPECTED_ZLIB_RETURN
;
744 else if (ret
== Z_OK
)
745 ret
= PNG_UNEXPECTED_ZLIB_RETURN
;
747 /* Release the claimed stream */
751 else /* the claim failed */ if (ret
== Z_STREAM_END
) /* impossible! */
752 ret
= PNG_UNEXPECTED_ZLIB_RETURN
;
759 /* Application/configuration limits exceeded */
760 png_zstream_error(png_ptr
, Z_MEM_ERROR
);
764 #endif /* READ_zTXt || READ_iTXt */
765 #endif /* READ_COMPRESSED_TEXT */
767 #ifdef PNG_READ_iCCP_SUPPORTED
768 /* Perform a partial read and decompress, producing 'avail_out' bytes and
769 * reading from the current chunk as required.
772 png_inflate_read(png_structrp png_ptr
, png_bytep read_buffer
, uInt read_size
,
773 png_uint_32p chunk_bytes
, png_bytep next_out
, png_alloc_size_t
*out_size
,
776 if (png_ptr
->zowner
== png_ptr
->chunk_name
)
780 /* next_in and avail_in must have been initialized by the caller. */
781 png_ptr
->zstream
.next_out
= next_out
;
782 png_ptr
->zstream
.avail_out
= 0; /* set in the loop */
786 if (png_ptr
->zstream
.avail_in
== 0)
788 if (read_size
> *chunk_bytes
)
789 read_size
= (uInt
)*chunk_bytes
;
790 *chunk_bytes
-= read_size
;
793 png_crc_read(png_ptr
, read_buffer
, read_size
);
795 png_ptr
->zstream
.next_in
= read_buffer
;
796 png_ptr
->zstream
.avail_in
= read_size
;
799 if (png_ptr
->zstream
.avail_out
== 0)
801 uInt avail
= ZLIB_IO_MAX
;
802 if (avail
> *out_size
)
803 avail
= (uInt
)*out_size
;
806 png_ptr
->zstream
.avail_out
= avail
;
809 /* Use Z_SYNC_FLUSH when there is no more chunk data to ensure that all
810 * the available output is produced; this allows reading of truncated
813 ret
= PNG_INFLATE(png_ptr
, *chunk_bytes
> 0 ?
814 Z_NO_FLUSH
: (finish
? Z_FINISH
: Z_SYNC_FLUSH
));
816 while (ret
== Z_OK
&& (*out_size
> 0 || png_ptr
->zstream
.avail_out
> 0));
818 *out_size
+= png_ptr
->zstream
.avail_out
;
819 png_ptr
->zstream
.avail_out
= 0; /* Should not be required, but is safe */
821 /* Ensure the error message pointer is always set: */
822 png_zstream_error(png_ptr
, ret
);
828 png_ptr
->zstream
.msg
= PNGZ_MSG_CAST("zstream unclaimed");
829 return Z_STREAM_ERROR
;
832 #endif /* READ_iCCP */
834 /* Read and check the IDHR chunk */
837 png_handle_IHDR(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
840 png_uint_32 width
, height
;
841 int bit_depth
, color_type
, compression_type
, filter_type
;
844 png_debug(1, "in png_handle_IHDR");
846 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) != 0)
847 png_chunk_error(png_ptr
, "out of place");
849 /* Check the length */
851 png_chunk_error(png_ptr
, "invalid");
853 png_ptr
->mode
|= PNG_HAVE_IHDR
;
855 png_crc_read(png_ptr
, buf
, 13);
856 png_crc_finish(png_ptr
, 0);
858 width
= png_get_uint_31(png_ptr
, buf
);
859 height
= png_get_uint_31(png_ptr
, buf
+ 4);
862 compression_type
= buf
[10];
863 filter_type
= buf
[11];
864 interlace_type
= buf
[12];
866 #ifdef PNG_READ_APNG_SUPPORTED
867 png_ptr
->first_frame_width
= width
;
868 png_ptr
->first_frame_height
= height
;
871 /* Set internal variables */
872 png_ptr
->width
= width
;
873 png_ptr
->height
= height
;
874 png_ptr
->bit_depth
= (png_byte
)bit_depth
;
875 png_ptr
->interlaced
= (png_byte
)interlace_type
;
876 png_ptr
->color_type
= (png_byte
)color_type
;
877 #ifdef PNG_MNG_FEATURES_SUPPORTED
878 png_ptr
->filter_type
= (png_byte
)filter_type
;
880 png_ptr
->compression_type
= (png_byte
)compression_type
;
882 /* Find number of channels */
883 switch (png_ptr
->color_type
)
885 default: /* invalid, png_set_IHDR calls png_error */
886 case PNG_COLOR_TYPE_GRAY
:
887 case PNG_COLOR_TYPE_PALETTE
:
888 png_ptr
->channels
= 1;
891 case PNG_COLOR_TYPE_RGB
:
892 png_ptr
->channels
= 3;
895 case PNG_COLOR_TYPE_GRAY_ALPHA
:
896 png_ptr
->channels
= 2;
899 case PNG_COLOR_TYPE_RGB_ALPHA
:
900 png_ptr
->channels
= 4;
904 /* Set up other useful info */
905 png_ptr
->pixel_depth
= (png_byte
)(png_ptr
->bit_depth
* png_ptr
->channels
);
906 png_ptr
->rowbytes
= PNG_ROWBYTES(png_ptr
->pixel_depth
, png_ptr
->width
);
907 png_debug1(3, "bit_depth = %d", png_ptr
->bit_depth
);
908 png_debug1(3, "channels = %d", png_ptr
->channels
);
909 png_debug1(3, "rowbytes = %lu", (unsigned long)png_ptr
->rowbytes
);
910 png_set_IHDR(png_ptr
, info_ptr
, width
, height
, bit_depth
,
911 color_type
, interlace_type
, compression_type
, filter_type
);
914 /* Read and check the palette */
916 png_handle_PLTE(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
918 png_color palette
[PNG_MAX_PALETTE_LENGTH
];
919 int max_palette_length
, num
, i
;
920 #ifdef PNG_POINTER_INDEXING_SUPPORTED
924 png_debug(1, "in png_handle_PLTE");
926 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
927 png_chunk_error(png_ptr
, "missing IHDR");
929 /* Moved to before the 'after IDAT' check below because otherwise duplicate
930 * PLTE chunks are potentially ignored (the spec says there shall not be more
931 * than one PLTE, the error is not treated as benign, so this check trumps
932 * the requirement that PLTE appears before IDAT.)
934 else if ((png_ptr
->mode
& PNG_HAVE_PLTE
) != 0)
935 png_chunk_error(png_ptr
, "duplicate");
937 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
939 /* This is benign because the non-benign error happened before, when an
940 * IDAT was encountered in a color-mapped image with no PLTE.
942 png_crc_finish(png_ptr
, length
);
943 png_chunk_benign_error(png_ptr
, "out of place");
947 png_ptr
->mode
|= PNG_HAVE_PLTE
;
949 if ((png_ptr
->color_type
& PNG_COLOR_MASK_COLOR
) == 0)
951 png_crc_finish(png_ptr
, length
);
952 png_chunk_benign_error(png_ptr
, "ignored in grayscale PNG");
956 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
957 if (png_ptr
->color_type
!= PNG_COLOR_TYPE_PALETTE
)
959 png_crc_finish(png_ptr
, length
);
964 if (length
> 3*PNG_MAX_PALETTE_LENGTH
|| length
% 3)
966 png_crc_finish(png_ptr
, length
);
968 if (png_ptr
->color_type
!= PNG_COLOR_TYPE_PALETTE
)
969 png_chunk_benign_error(png_ptr
, "invalid");
972 png_chunk_error(png_ptr
, "invalid");
977 /* The cast is safe because 'length' is less than 3*PNG_MAX_PALETTE_LENGTH */
978 num
= (int)length
/ 3;
980 /* If the palette has 256 or fewer entries but is too large for the bit
981 * depth, we don't issue an error, to preserve the behavior of previous
982 * libpng versions. We silently truncate the unused extra palette entries
985 if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
986 max_palette_length
= (1 << png_ptr
->bit_depth
);
988 max_palette_length
= PNG_MAX_PALETTE_LENGTH
;
990 if (num
> max_palette_length
)
991 num
= max_palette_length
;
993 #ifdef PNG_POINTER_INDEXING_SUPPORTED
994 for (i
= 0, pal_ptr
= palette
; i
< num
; i
++, pal_ptr
++)
998 png_crc_read(png_ptr
, buf
, 3);
999 pal_ptr
->red
= buf
[0];
1000 pal_ptr
->green
= buf
[1];
1001 pal_ptr
->blue
= buf
[2];
1004 for (i
= 0; i
< num
; i
++)
1008 png_crc_read(png_ptr
, buf
, 3);
1009 /* Don't depend upon png_color being any order */
1010 palette
[i
].red
= buf
[0];
1011 palette
[i
].green
= buf
[1];
1012 palette
[i
].blue
= buf
[2];
1016 /* If we actually need the PLTE chunk (ie for a paletted image), we do
1017 * whatever the normal CRC configuration tells us. However, if we
1018 * have an RGB image, the PLTE can be considered ancillary, so
1019 * we will act as though it is.
1021 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
1022 if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
1025 png_crc_finish(png_ptr
, (png_uint_32
) (length
- (unsigned int)num
* 3));
1028 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
1029 else if (png_crc_error(png_ptr
) != 0) /* Only if we have a CRC error */
1031 /* If we don't want to use the data from an ancillary chunk,
1032 * we have two options: an error abort, or a warning and we
1033 * ignore the data in this chunk (which should be OK, since
1034 * it's considered ancillary for a RGB or RGBA image).
1036 * IMPLEMENTATION NOTE: this is only here because png_crc_finish uses the
1037 * chunk type to determine whether to check the ancillary or the critical
1040 if ((png_ptr
->flags
& PNG_FLAG_CRC_ANCILLARY_USE
) == 0)
1042 if ((png_ptr
->flags
& PNG_FLAG_CRC_ANCILLARY_NOWARN
) != 0)
1046 png_chunk_error(png_ptr
, "CRC error");
1049 /* Otherwise, we (optionally) emit a warning and use the chunk. */
1050 else if ((png_ptr
->flags
& PNG_FLAG_CRC_ANCILLARY_NOWARN
) == 0)
1051 png_chunk_warning(png_ptr
, "CRC error");
1055 /* TODO: png_set_PLTE has the side effect of setting png_ptr->palette to its
1056 * own copy of the palette. This has the side effect that when png_start_row
1057 * is called (this happens after any call to png_read_update_info) the
1058 * info_ptr palette gets changed. This is extremely unexpected and
1061 * Fix this by not sharing the palette in this way.
1063 png_set_PLTE(png_ptr
, info_ptr
, palette
, num
);
1065 /* The three chunks, bKGD, hIST and tRNS *must* appear after PLTE and before
1066 * IDAT. Prior to 1.6.0 this was not checked; instead the code merely
1067 * checked the apparent validity of a tRNS chunk inserted before PLTE on a
1068 * palette PNG. 1.6.0 attempts to rigorously follow the standard and
1069 * therefore does a benign error if the erroneous condition is detected *and*
1070 * cancels the tRNS if the benign error returns. The alternative is to
1071 * amend the standard since it would be rather hypocritical of the standards
1072 * maintainers to ignore it.
1074 #ifdef PNG_READ_tRNS_SUPPORTED
1075 if (png_ptr
->num_trans
> 0 ||
1076 (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_tRNS
) != 0))
1078 /* Cancel this because otherwise it would be used if the transforms
1079 * require it. Don't cancel the 'valid' flag because this would prevent
1080 * detection of duplicate chunks.
1082 png_ptr
->num_trans
= 0;
1084 if (info_ptr
!= NULL
)
1085 info_ptr
->num_trans
= 0;
1087 png_chunk_benign_error(png_ptr
, "tRNS must be after");
1091 #ifdef PNG_READ_hIST_SUPPORTED
1092 if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_hIST
) != 0)
1093 png_chunk_benign_error(png_ptr
, "hIST must be after");
1096 #ifdef PNG_READ_bKGD_SUPPORTED
1097 if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_bKGD
) != 0)
1098 png_chunk_benign_error(png_ptr
, "bKGD must be after");
1103 png_handle_IEND(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1105 png_debug(1, "in png_handle_IEND");
1107 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0 ||
1108 (png_ptr
->mode
& PNG_HAVE_IDAT
) == 0)
1109 png_chunk_error(png_ptr
, "out of place");
1111 png_ptr
->mode
|= (PNG_AFTER_IDAT
| PNG_HAVE_IEND
);
1113 png_crc_finish(png_ptr
, length
);
1116 png_chunk_benign_error(png_ptr
, "invalid");
1118 PNG_UNUSED(info_ptr
)
1121 #ifdef PNG_READ_gAMA_SUPPORTED
1123 png_handle_gAMA(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1125 png_fixed_point igamma
;
1128 png_debug(1, "in png_handle_gAMA");
1130 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1131 png_chunk_error(png_ptr
, "missing IHDR");
1133 else if ((png_ptr
->mode
& (PNG_HAVE_IDAT
|PNG_HAVE_PLTE
)) != 0)
1135 png_crc_finish(png_ptr
, length
);
1136 png_chunk_benign_error(png_ptr
, "out of place");
1142 png_crc_finish(png_ptr
, length
);
1143 png_chunk_benign_error(png_ptr
, "invalid");
1147 png_crc_read(png_ptr
, buf
, 4);
1149 if (png_crc_finish(png_ptr
, 0) != 0)
1152 igamma
= png_get_fixed_point(NULL
, buf
);
1154 png_colorspace_set_gamma(png_ptr
, &png_ptr
->colorspace
, igamma
);
1155 png_colorspace_sync(png_ptr
, info_ptr
);
1159 #ifdef PNG_READ_sBIT_SUPPORTED
1161 png_handle_sBIT(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1163 unsigned int truelen
, i
;
1164 png_byte sample_depth
;
1167 png_debug(1, "in png_handle_sBIT");
1169 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1170 png_chunk_error(png_ptr
, "missing IHDR");
1172 else if ((png_ptr
->mode
& (PNG_HAVE_IDAT
|PNG_HAVE_PLTE
)) != 0)
1174 png_crc_finish(png_ptr
, length
);
1175 png_chunk_benign_error(png_ptr
, "out of place");
1179 if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_sBIT
) != 0)
1181 png_crc_finish(png_ptr
, length
);
1182 png_chunk_benign_error(png_ptr
, "duplicate");
1186 if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
1194 truelen
= png_ptr
->channels
;
1195 sample_depth
= png_ptr
->bit_depth
;
1198 if (length
!= truelen
|| length
> 4)
1200 png_chunk_benign_error(png_ptr
, "invalid");
1201 png_crc_finish(png_ptr
, length
);
1205 buf
[0] = buf
[1] = buf
[2] = buf
[3] = sample_depth
;
1206 png_crc_read(png_ptr
, buf
, truelen
);
1208 if (png_crc_finish(png_ptr
, 0) != 0)
1211 for (i
=0; i
<truelen
; ++i
)
1213 if (buf
[i
] == 0 || buf
[i
] > sample_depth
)
1215 png_chunk_benign_error(png_ptr
, "invalid");
1220 if ((png_ptr
->color_type
& PNG_COLOR_MASK_COLOR
) != 0)
1222 png_ptr
->sig_bit
.red
= buf
[0];
1223 png_ptr
->sig_bit
.green
= buf
[1];
1224 png_ptr
->sig_bit
.blue
= buf
[2];
1225 png_ptr
->sig_bit
.alpha
= buf
[3];
1230 png_ptr
->sig_bit
.gray
= buf
[0];
1231 png_ptr
->sig_bit
.red
= buf
[0];
1232 png_ptr
->sig_bit
.green
= buf
[0];
1233 png_ptr
->sig_bit
.blue
= buf
[0];
1234 png_ptr
->sig_bit
.alpha
= buf
[1];
1237 png_set_sBIT(png_ptr
, info_ptr
, &(png_ptr
->sig_bit
));
1241 #ifdef PNG_READ_cHRM_SUPPORTED
1243 png_handle_cHRM(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1248 png_debug(1, "in png_handle_cHRM");
1250 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1251 png_chunk_error(png_ptr
, "missing IHDR");
1253 else if ((png_ptr
->mode
& (PNG_HAVE_IDAT
|PNG_HAVE_PLTE
)) != 0)
1255 png_crc_finish(png_ptr
, length
);
1256 png_chunk_benign_error(png_ptr
, "out of place");
1262 png_crc_finish(png_ptr
, length
);
1263 png_chunk_benign_error(png_ptr
, "invalid");
1267 png_crc_read(png_ptr
, buf
, 32);
1269 if (png_crc_finish(png_ptr
, 0) != 0)
1272 xy
.whitex
= png_get_fixed_point(NULL
, buf
);
1273 xy
.whitey
= png_get_fixed_point(NULL
, buf
+ 4);
1274 xy
.redx
= png_get_fixed_point(NULL
, buf
+ 8);
1275 xy
.redy
= png_get_fixed_point(NULL
, buf
+ 12);
1276 xy
.greenx
= png_get_fixed_point(NULL
, buf
+ 16);
1277 xy
.greeny
= png_get_fixed_point(NULL
, buf
+ 20);
1278 xy
.bluex
= png_get_fixed_point(NULL
, buf
+ 24);
1279 xy
.bluey
= png_get_fixed_point(NULL
, buf
+ 28);
1281 if (xy
.whitex
== PNG_FIXED_ERROR
||
1282 xy
.whitey
== PNG_FIXED_ERROR
||
1283 xy
.redx
== PNG_FIXED_ERROR
||
1284 xy
.redy
== PNG_FIXED_ERROR
||
1285 xy
.greenx
== PNG_FIXED_ERROR
||
1286 xy
.greeny
== PNG_FIXED_ERROR
||
1287 xy
.bluex
== PNG_FIXED_ERROR
||
1288 xy
.bluey
== PNG_FIXED_ERROR
)
1290 png_chunk_benign_error(png_ptr
, "invalid values");
1294 /* If a colorspace error has already been output skip this chunk */
1295 if ((png_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
) != 0)
1298 if ((png_ptr
->colorspace
.flags
& PNG_COLORSPACE_FROM_cHRM
) != 0)
1300 png_ptr
->colorspace
.flags
|= PNG_COLORSPACE_INVALID
;
1301 png_colorspace_sync(png_ptr
, info_ptr
);
1302 png_chunk_benign_error(png_ptr
, "duplicate");
1306 png_ptr
->colorspace
.flags
|= PNG_COLORSPACE_FROM_cHRM
;
1307 (void)png_colorspace_set_chromaticities(png_ptr
, &png_ptr
->colorspace
, &xy
,
1308 1/*prefer cHRM values*/);
1309 png_colorspace_sync(png_ptr
, info_ptr
);
1313 #ifdef PNG_READ_sRGB_SUPPORTED
1315 png_handle_sRGB(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1319 png_debug(1, "in png_handle_sRGB");
1321 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1322 png_chunk_error(png_ptr
, "missing IHDR");
1324 else if ((png_ptr
->mode
& (PNG_HAVE_IDAT
|PNG_HAVE_PLTE
)) != 0)
1326 png_crc_finish(png_ptr
, length
);
1327 png_chunk_benign_error(png_ptr
, "out of place");
1333 png_crc_finish(png_ptr
, length
);
1334 png_chunk_benign_error(png_ptr
, "invalid");
1338 png_crc_read(png_ptr
, &intent
, 1);
1340 if (png_crc_finish(png_ptr
, 0) != 0)
1343 /* If a colorspace error has already been output skip this chunk */
1344 if ((png_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
) != 0)
1347 /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
1350 if ((png_ptr
->colorspace
.flags
& PNG_COLORSPACE_HAVE_INTENT
) != 0)
1352 png_ptr
->colorspace
.flags
|= PNG_COLORSPACE_INVALID
;
1353 png_colorspace_sync(png_ptr
, info_ptr
);
1354 png_chunk_benign_error(png_ptr
, "too many profiles");
1358 (void)png_colorspace_set_sRGB(png_ptr
, &png_ptr
->colorspace
, intent
);
1359 png_colorspace_sync(png_ptr
, info_ptr
);
1361 #endif /* READ_sRGB */
1363 #ifdef PNG_READ_iCCP_SUPPORTED
1365 png_handle_iCCP(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1366 /* Note: this does not properly handle profiles that are > 64K under DOS */
1368 png_const_charp errmsg
= NULL
; /* error message output, or no error */
1369 int finished
= 0; /* crc checked */
1371 png_debug(1, "in png_handle_iCCP");
1373 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1374 png_chunk_error(png_ptr
, "missing IHDR");
1376 else if ((png_ptr
->mode
& (PNG_HAVE_IDAT
|PNG_HAVE_PLTE
)) != 0)
1378 png_crc_finish(png_ptr
, length
);
1379 png_chunk_benign_error(png_ptr
, "out of place");
1383 /* Consistent with all the above colorspace handling an obviously *invalid*
1384 * chunk is just ignored, so does not invalidate the color space. An
1385 * alternative is to set the 'invalid' flags at the start of this routine
1386 * and only clear them in they were not set before and all the tests pass.
1389 /* The keyword must be at least one character and there is a
1390 * terminator (0) byte and the compression method byte, and the
1391 * 'zlib' datastream is at least 11 bytes.
1395 png_crc_finish(png_ptr
, length
);
1396 png_chunk_benign_error(png_ptr
, "too short");
1400 /* If a colorspace error has already been output skip this chunk */
1401 if ((png_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
) != 0)
1403 png_crc_finish(png_ptr
, length
);
1407 /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
1410 if ((png_ptr
->colorspace
.flags
& PNG_COLORSPACE_HAVE_INTENT
) == 0)
1412 uInt read_length
, keyword_length
;
1415 /* Find the keyword; the keyword plus separator and compression method
1416 * bytes can be at most 81 characters long.
1418 read_length
= 81; /* maximum */
1419 if (read_length
> length
)
1420 read_length
= (uInt
)length
;
1422 png_crc_read(png_ptr
, (png_bytep
)keyword
, read_length
);
1423 length
-= read_length
;
1425 /* The minimum 'zlib' stream is assumed to be just the 2 byte header,
1426 * 5 bytes minimum 'deflate' stream, and the 4 byte checksum.
1430 png_crc_finish(png_ptr
, length
);
1431 png_chunk_benign_error(png_ptr
, "too short");
1436 while (keyword_length
< 80 && keyword_length
< read_length
&&
1437 keyword
[keyword_length
] != 0)
1440 /* TODO: make the keyword checking common */
1441 if (keyword_length
>= 1 && keyword_length
<= 79)
1443 /* We only understand '0' compression - deflate - so if we get a
1444 * different value we can't safely decode the chunk.
1446 if (keyword_length
+1 < read_length
&&
1447 keyword
[keyword_length
+1] == PNG_COMPRESSION_TYPE_BASE
)
1449 read_length
-= keyword_length
+2;
1451 if (png_inflate_claim(png_ptr
, png_iCCP
) == Z_OK
)
1453 Byte profile_header
[132]={0};
1454 Byte local_buffer
[PNG_INFLATE_BUF_SIZE
];
1455 png_alloc_size_t size
= (sizeof profile_header
);
1457 png_ptr
->zstream
.next_in
= (Bytef
*)keyword
+ (keyword_length
+2);
1458 png_ptr
->zstream
.avail_in
= read_length
;
1459 (void)png_inflate_read(png_ptr
, local_buffer
,
1460 (sizeof local_buffer
), &length
, profile_header
, &size
,
1461 0/*finish: don't, because the output is too small*/);
1465 /* We have the ICC profile header; do the basic header checks.
1467 png_uint_32 profile_length
= png_get_uint_32(profile_header
);
1469 if (png_icc_check_length(png_ptr
, &png_ptr
->colorspace
,
1470 keyword
, profile_length
) != 0)
1472 /* The length is apparently ok, so we can check the 132
1475 if (png_icc_check_header(png_ptr
, &png_ptr
->colorspace
,
1476 keyword
, profile_length
, profile_header
,
1477 png_ptr
->color_type
) != 0)
1479 /* Now read the tag table; a variable size buffer is
1480 * needed at this point, allocate one for the whole
1481 * profile. The header check has already validated
1482 * that none of this stuff will overflow.
1484 png_uint_32 tag_count
=
1485 png_get_uint_32(profile_header
+ 128);
1486 png_bytep profile
= png_read_buffer(png_ptr
,
1487 profile_length
, 2/*silent*/);
1489 if (profile
!= NULL
)
1491 memcpy(profile
, profile_header
,
1492 (sizeof profile_header
));
1494 size
= 12 * tag_count
;
1496 (void)png_inflate_read(png_ptr
, local_buffer
,
1497 (sizeof local_buffer
), &length
,
1498 profile
+ (sizeof profile_header
), &size
, 0);
1500 /* Still expect a buffer error because we expect
1501 * there to be some tag data!
1505 if (png_icc_check_tag_table(png_ptr
,
1506 &png_ptr
->colorspace
, keyword
, profile_length
,
1509 /* The profile has been validated for basic
1510 * security issues, so read the whole thing in.
1512 size
= profile_length
- (sizeof profile_header
)
1515 (void)png_inflate_read(png_ptr
, local_buffer
,
1516 (sizeof local_buffer
), &length
,
1517 profile
+ (sizeof profile_header
) +
1518 12 * tag_count
, &size
, 1/*finish*/);
1520 if (length
> 0 && !(png_ptr
->flags
&
1521 PNG_FLAG_BENIGN_ERRORS_WARN
))
1522 errmsg
= "extra compressed data";
1524 /* But otherwise allow extra data: */
1529 /* This can be handled completely, so
1532 png_chunk_warning(png_ptr
,
1533 "extra compressed data");
1536 png_crc_finish(png_ptr
, length
);
1539 # if defined(PNG_sRGB_SUPPORTED) && PNG_sRGB_PROFILE_CHECKS >= 0
1540 /* Check for a match against sRGB */
1541 png_icc_set_sRGB(png_ptr
,
1542 &png_ptr
->colorspace
, profile
,
1543 png_ptr
->zstream
.adler
);
1546 /* Steal the profile for info_ptr. */
1547 if (info_ptr
!= NULL
)
1549 png_free_data(png_ptr
, info_ptr
,
1552 info_ptr
->iccp_name
= png_voidcast(char*,
1553 png_malloc_base(png_ptr
,
1555 if (info_ptr
->iccp_name
!= NULL
)
1557 memcpy(info_ptr
->iccp_name
, keyword
,
1559 info_ptr
->iccp_proflen
=
1561 info_ptr
->iccp_profile
= profile
;
1562 png_ptr
->read_buffer
= NULL
; /*steal*/
1563 info_ptr
->free_me
|= PNG_FREE_ICCP
;
1564 info_ptr
->valid
|= PNG_INFO_iCCP
;
1569 png_ptr
->colorspace
.flags
|=
1570 PNG_COLORSPACE_INVALID
;
1571 errmsg
= "out of memory";
1575 /* else the profile remains in the read
1576 * buffer which gets reused for subsequent
1580 if (info_ptr
!= NULL
)
1581 png_colorspace_sync(png_ptr
, info_ptr
);
1585 png_ptr
->zowner
= 0;
1590 errmsg
= png_ptr
->zstream
.msg
;
1592 /* else png_icc_check_tag_table output an error */
1594 else /* profile truncated */
1595 errmsg
= png_ptr
->zstream
.msg
;
1599 errmsg
= "out of memory";
1602 /* else png_icc_check_header output an error */
1605 /* else png_icc_check_length output an error */
1608 else /* profile truncated */
1609 errmsg
= png_ptr
->zstream
.msg
;
1611 /* Release the stream */
1612 png_ptr
->zowner
= 0;
1615 else /* png_inflate_claim failed */
1616 errmsg
= png_ptr
->zstream
.msg
;
1620 errmsg
= "bad compression method"; /* or missing */
1624 errmsg
= "bad keyword";
1628 errmsg
= "too many profiles";
1630 /* Failure: the reason is in 'errmsg' */
1632 png_crc_finish(png_ptr
, length
);
1634 png_ptr
->colorspace
.flags
|= PNG_COLORSPACE_INVALID
;
1635 png_colorspace_sync(png_ptr
, info_ptr
);
1636 if (errmsg
!= NULL
) /* else already output */
1637 png_chunk_benign_error(png_ptr
, errmsg
);
1639 #endif /* READ_iCCP */
1641 #ifdef PNG_READ_sPLT_SUPPORTED
1643 png_handle_sPLT(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1644 /* Note: this does not properly handle chunks that are > 64K under DOS */
1646 png_bytep entry_start
, buffer
;
1647 png_sPLT_t new_palette
;
1649 png_uint_32 data_length
;
1651 png_uint_32 skip
= 0;
1655 png_debug(1, "in png_handle_sPLT");
1657 #ifdef PNG_USER_LIMITS_SUPPORTED
1658 if (png_ptr
->user_chunk_cache_max
!= 0)
1660 if (png_ptr
->user_chunk_cache_max
== 1)
1662 png_crc_finish(png_ptr
, length
);
1666 if (--png_ptr
->user_chunk_cache_max
== 1)
1668 png_warning(png_ptr
, "No space in chunk cache for sPLT");
1669 png_crc_finish(png_ptr
, length
);
1675 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1676 png_chunk_error(png_ptr
, "missing IHDR");
1678 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
1680 png_crc_finish(png_ptr
, length
);
1681 png_chunk_benign_error(png_ptr
, "out of place");
1685 #ifdef PNG_MAX_MALLOC_64K
1686 if (length
> 65535U)
1688 png_crc_finish(png_ptr
, length
);
1689 png_chunk_benign_error(png_ptr
, "too large to fit in memory");
1694 buffer
= png_read_buffer(png_ptr
, length
+1, 2/*silent*/);
1697 png_crc_finish(png_ptr
, length
);
1698 png_chunk_benign_error(png_ptr
, "out of memory");
1703 /* WARNING: this may break if size_t is less than 32 bits; it is assumed
1704 * that the PNG_MAX_MALLOC_64K test is enabled in this case, but this is a
1705 * potential breakage point if the types in pngconf.h aren't exactly right.
1707 png_crc_read(png_ptr
, buffer
, length
);
1709 if (png_crc_finish(png_ptr
, skip
) != 0)
1714 for (entry_start
= buffer
; *entry_start
; entry_start
++)
1715 /* Empty loop to find end of name */ ;
1719 /* A sample depth should follow the separator, and we should be on it */
1720 if (length
< 2U || entry_start
> buffer
+ (length
- 2U))
1722 png_warning(png_ptr
, "malformed sPLT chunk");
1726 new_palette
.depth
= *entry_start
++;
1727 entry_size
= (new_palette
.depth
== 8 ? 6 : 10);
1728 /* This must fit in a png_uint_32 because it is derived from the original
1729 * chunk data length.
1731 data_length
= length
- (png_uint_32
)(entry_start
- buffer
);
1733 /* Integrity-check the data length */
1734 if ((data_length
% (unsigned int)entry_size
) != 0)
1736 png_warning(png_ptr
, "sPLT chunk has bad length");
1740 dl
= (png_uint_32
)(data_length
/ (unsigned int)entry_size
);
1741 max_dl
= PNG_SIZE_MAX
/ (sizeof (png_sPLT_entry
));
1745 png_warning(png_ptr
, "sPLT chunk too long");
1749 new_palette
.nentries
= (png_int_32
)(data_length
/ (unsigned int)entry_size
);
1751 new_palette
.entries
= (png_sPLT_entryp
)png_malloc_warn(png_ptr
,
1752 (png_alloc_size_t
) new_palette
.nentries
* (sizeof (png_sPLT_entry
)));
1754 if (new_palette
.entries
== NULL
)
1756 png_warning(png_ptr
, "sPLT chunk requires too much memory");
1760 #ifdef PNG_POINTER_INDEXING_SUPPORTED
1761 for (i
= 0; i
< new_palette
.nentries
; i
++)
1763 pp
= new_palette
.entries
+ i
;
1765 if (new_palette
.depth
== 8)
1767 pp
->red
= *entry_start
++;
1768 pp
->green
= *entry_start
++;
1769 pp
->blue
= *entry_start
++;
1770 pp
->alpha
= *entry_start
++;
1775 pp
->red
= png_get_uint_16(entry_start
); entry_start
+= 2;
1776 pp
->green
= png_get_uint_16(entry_start
); entry_start
+= 2;
1777 pp
->blue
= png_get_uint_16(entry_start
); entry_start
+= 2;
1778 pp
->alpha
= png_get_uint_16(entry_start
); entry_start
+= 2;
1781 pp
->frequency
= png_get_uint_16(entry_start
); entry_start
+= 2;
1784 pp
= new_palette
.entries
;
1786 for (i
= 0; i
< new_palette
.nentries
; i
++)
1789 if (new_palette
.depth
== 8)
1791 pp
[i
].red
= *entry_start
++;
1792 pp
[i
].green
= *entry_start
++;
1793 pp
[i
].blue
= *entry_start
++;
1794 pp
[i
].alpha
= *entry_start
++;
1799 pp
[i
].red
= png_get_uint_16(entry_start
); entry_start
+= 2;
1800 pp
[i
].green
= png_get_uint_16(entry_start
); entry_start
+= 2;
1801 pp
[i
].blue
= png_get_uint_16(entry_start
); entry_start
+= 2;
1802 pp
[i
].alpha
= png_get_uint_16(entry_start
); entry_start
+= 2;
1805 pp
[i
].frequency
= png_get_uint_16(entry_start
); entry_start
+= 2;
1809 /* Discard all chunk data except the name and stash that */
1810 new_palette
.name
= (png_charp
)buffer
;
1812 png_set_sPLT(png_ptr
, info_ptr
, &new_palette
, 1);
1814 png_free(png_ptr
, new_palette
.entries
);
1816 #endif /* READ_sPLT */
1818 #ifdef PNG_READ_tRNS_SUPPORTED
1820 png_handle_tRNS(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1822 png_byte readbuf
[PNG_MAX_PALETTE_LENGTH
];
1824 png_debug(1, "in png_handle_tRNS");
1826 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1827 png_chunk_error(png_ptr
, "missing IHDR");
1829 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
1831 png_crc_finish(png_ptr
, length
);
1832 png_chunk_benign_error(png_ptr
, "out of place");
1836 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_tRNS
) != 0)
1838 png_crc_finish(png_ptr
, length
);
1839 png_chunk_benign_error(png_ptr
, "duplicate");
1843 if (png_ptr
->color_type
== PNG_COLOR_TYPE_GRAY
)
1849 png_crc_finish(png_ptr
, length
);
1850 png_chunk_benign_error(png_ptr
, "invalid");
1854 png_crc_read(png_ptr
, buf
, 2);
1855 png_ptr
->num_trans
= 1;
1856 png_ptr
->trans_color
.gray
= png_get_uint_16(buf
);
1859 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_RGB
)
1865 png_crc_finish(png_ptr
, length
);
1866 png_chunk_benign_error(png_ptr
, "invalid");
1870 png_crc_read(png_ptr
, buf
, length
);
1871 png_ptr
->num_trans
= 1;
1872 png_ptr
->trans_color
.red
= png_get_uint_16(buf
);
1873 png_ptr
->trans_color
.green
= png_get_uint_16(buf
+ 2);
1874 png_ptr
->trans_color
.blue
= png_get_uint_16(buf
+ 4);
1877 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
1879 if ((png_ptr
->mode
& PNG_HAVE_PLTE
) == 0)
1881 /* TODO: is this actually an error in the ISO spec? */
1882 png_crc_finish(png_ptr
, length
);
1883 png_chunk_benign_error(png_ptr
, "out of place");
1887 if (length
> (unsigned int) png_ptr
->num_palette
||
1888 length
> (unsigned int) PNG_MAX_PALETTE_LENGTH
||
1891 png_crc_finish(png_ptr
, length
);
1892 png_chunk_benign_error(png_ptr
, "invalid");
1896 png_crc_read(png_ptr
, readbuf
, length
);
1897 png_ptr
->num_trans
= (png_uint_16
)length
;
1902 png_crc_finish(png_ptr
, length
);
1903 png_chunk_benign_error(png_ptr
, "invalid with alpha channel");
1907 if (png_crc_finish(png_ptr
, 0) != 0)
1909 png_ptr
->num_trans
= 0;
1913 /* TODO: this is a horrible side effect in the palette case because the
1914 * png_struct ends up with a pointer to the tRNS buffer owned by the
1915 * png_info. Fix this.
1917 png_set_tRNS(png_ptr
, info_ptr
, readbuf
, png_ptr
->num_trans
,
1918 &(png_ptr
->trans_color
));
1922 #ifdef PNG_READ_bKGD_SUPPORTED
1924 png_handle_bKGD(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1926 unsigned int truelen
;
1928 png_color_16 background
;
1930 png_debug(1, "in png_handle_bKGD");
1932 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1933 png_chunk_error(png_ptr
, "missing IHDR");
1935 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0 ||
1936 (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
&&
1937 (png_ptr
->mode
& PNG_HAVE_PLTE
) == 0))
1939 png_crc_finish(png_ptr
, length
);
1940 png_chunk_benign_error(png_ptr
, "out of place");
1944 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_bKGD
) != 0)
1946 png_crc_finish(png_ptr
, length
);
1947 png_chunk_benign_error(png_ptr
, "duplicate");
1951 if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
1954 else if ((png_ptr
->color_type
& PNG_COLOR_MASK_COLOR
) != 0)
1960 if (length
!= truelen
)
1962 png_crc_finish(png_ptr
, length
);
1963 png_chunk_benign_error(png_ptr
, "invalid");
1967 png_crc_read(png_ptr
, buf
, truelen
);
1969 if (png_crc_finish(png_ptr
, 0) != 0)
1972 /* We convert the index value into RGB components so that we can allow
1973 * arbitrary RGB values for background when we have transparency, and
1974 * so it is easy to determine the RGB values of the background color
1975 * from the info_ptr struct.
1977 if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
1979 background
.index
= buf
[0];
1981 if (info_ptr
!= NULL
&& info_ptr
->num_palette
!= 0)
1983 if (buf
[0] >= info_ptr
->num_palette
)
1985 png_chunk_benign_error(png_ptr
, "invalid index");
1989 background
.red
= (png_uint_16
)png_ptr
->palette
[buf
[0]].red
;
1990 background
.green
= (png_uint_16
)png_ptr
->palette
[buf
[0]].green
;
1991 background
.blue
= (png_uint_16
)png_ptr
->palette
[buf
[0]].blue
;
1995 background
.red
= background
.green
= background
.blue
= 0;
1997 background
.gray
= 0;
2000 else if ((png_ptr
->color_type
& PNG_COLOR_MASK_COLOR
) == 0) /* GRAY */
2002 if (png_ptr
->bit_depth
<= 8)
2004 if (buf
[0] != 0 || buf
[1] >= (unsigned int)(1 << png_ptr
->bit_depth
))
2006 png_chunk_benign_error(png_ptr
, "invalid gray level");
2011 background
.index
= 0;
2015 background
.gray
= png_get_uint_16(buf
);
2020 if (png_ptr
->bit_depth
<= 8)
2022 if (buf
[0] != 0 || buf
[2] != 0 || buf
[4] != 0)
2024 png_chunk_benign_error(png_ptr
, "invalid color");
2029 background
.index
= 0;
2030 background
.red
= png_get_uint_16(buf
);
2031 background
.green
= png_get_uint_16(buf
+ 2);
2032 background
.blue
= png_get_uint_16(buf
+ 4);
2033 background
.gray
= 0;
2036 png_set_bKGD(png_ptr
, info_ptr
, &background
);
2040 #ifdef PNG_READ_eXIf_SUPPORTED
2042 png_handle_eXIf(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2046 png_debug(1, "in png_handle_eXIf");
2048 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2049 png_chunk_error(png_ptr
, "missing IHDR");
2053 png_crc_finish(png_ptr
, length
);
2054 png_chunk_benign_error(png_ptr
, "too short");
2058 else if (info_ptr
== NULL
|| (info_ptr
->valid
& PNG_INFO_eXIf
) != 0)
2060 png_crc_finish(png_ptr
, length
);
2061 png_chunk_benign_error(png_ptr
, "duplicate");
2065 info_ptr
->free_me
|= PNG_FREE_EXIF
;
2067 info_ptr
->eXIf_buf
= png_voidcast(png_bytep
,
2068 png_malloc_warn(png_ptr
, length
));
2070 if (info_ptr
->eXIf_buf
== NULL
)
2072 png_crc_finish(png_ptr
, length
);
2073 png_chunk_benign_error(png_ptr
, "out of memory");
2077 for (i
= 0; i
< length
; i
++)
2080 png_crc_read(png_ptr
, buf
, 1);
2081 info_ptr
->eXIf_buf
[i
] = buf
[0];
2084 if ((buf
[0] != 'M' && buf
[0] != 'I') ||
2085 (info_ptr
->eXIf_buf
[0] != buf
[0]))
2087 png_crc_finish(png_ptr
, length
- 2);
2088 png_chunk_benign_error(png_ptr
, "incorrect byte-order specifier");
2089 png_free(png_ptr
, info_ptr
->eXIf_buf
);
2090 info_ptr
->eXIf_buf
= NULL
;
2096 if (png_crc_finish(png_ptr
, 0) == 0)
2097 png_set_eXIf_1(png_ptr
, info_ptr
, length
, info_ptr
->eXIf_buf
);
2099 png_free(png_ptr
, info_ptr
->eXIf_buf
);
2100 info_ptr
->eXIf_buf
= NULL
;
2104 #ifdef PNG_READ_hIST_SUPPORTED
2106 png_handle_hIST(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2108 unsigned int num
, i
;
2109 png_uint_16 readbuf
[PNG_MAX_PALETTE_LENGTH
];
2111 png_debug(1, "in png_handle_hIST");
2113 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2114 png_chunk_error(png_ptr
, "missing IHDR");
2116 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0 ||
2117 (png_ptr
->mode
& PNG_HAVE_PLTE
) == 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_hIST
) != 0)
2126 png_crc_finish(png_ptr
, length
);
2127 png_chunk_benign_error(png_ptr
, "duplicate");
2133 if (length
!= num
* 2 ||
2134 num
!= (unsigned int)png_ptr
->num_palette
||
2135 num
> (unsigned int)PNG_MAX_PALETTE_LENGTH
)
2137 png_crc_finish(png_ptr
, length
);
2138 png_chunk_benign_error(png_ptr
, "invalid");
2142 for (i
= 0; i
< num
; i
++)
2146 png_crc_read(png_ptr
, buf
, 2);
2147 readbuf
[i
] = png_get_uint_16(buf
);
2150 if (png_crc_finish(png_ptr
, 0) != 0)
2153 png_set_hIST(png_ptr
, info_ptr
, readbuf
);
2157 #ifdef PNG_READ_pHYs_SUPPORTED
2159 png_handle_pHYs(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2162 png_uint_32 res_x
, res_y
;
2165 png_debug(1, "in png_handle_pHYs");
2167 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2168 png_chunk_error(png_ptr
, "missing IHDR");
2170 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2172 png_crc_finish(png_ptr
, length
);
2173 png_chunk_benign_error(png_ptr
, "out of place");
2177 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_pHYs
) != 0)
2179 png_crc_finish(png_ptr
, length
);
2180 png_chunk_benign_error(png_ptr
, "duplicate");
2186 png_crc_finish(png_ptr
, length
);
2187 png_chunk_benign_error(png_ptr
, "invalid");
2191 png_crc_read(png_ptr
, buf
, 9);
2193 if (png_crc_finish(png_ptr
, 0) != 0)
2196 res_x
= png_get_uint_32(buf
);
2197 res_y
= png_get_uint_32(buf
+ 4);
2199 png_set_pHYs(png_ptr
, info_ptr
, res_x
, res_y
, unit_type
);
2203 #ifdef PNG_READ_oFFs_SUPPORTED
2205 png_handle_oFFs(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2208 png_int_32 offset_x
, offset_y
;
2211 png_debug(1, "in png_handle_oFFs");
2213 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2214 png_chunk_error(png_ptr
, "missing IHDR");
2216 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2218 png_crc_finish(png_ptr
, length
);
2219 png_chunk_benign_error(png_ptr
, "out of place");
2223 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_oFFs
) != 0)
2225 png_crc_finish(png_ptr
, length
);
2226 png_chunk_benign_error(png_ptr
, "duplicate");
2232 png_crc_finish(png_ptr
, length
);
2233 png_chunk_benign_error(png_ptr
, "invalid");
2237 png_crc_read(png_ptr
, buf
, 9);
2239 if (png_crc_finish(png_ptr
, 0) != 0)
2242 offset_x
= png_get_int_32(buf
);
2243 offset_y
= png_get_int_32(buf
+ 4);
2245 png_set_oFFs(png_ptr
, info_ptr
, offset_x
, offset_y
, unit_type
);
2249 #ifdef PNG_READ_pCAL_SUPPORTED
2250 /* Read the pCAL chunk (described in the PNG Extensions document) */
2252 png_handle_pCAL(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2255 png_byte type
, nparams
;
2256 png_bytep buffer
, buf
, units
, endptr
;
2260 png_debug(1, "in png_handle_pCAL");
2262 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2263 png_chunk_error(png_ptr
, "missing IHDR");
2265 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2267 png_crc_finish(png_ptr
, length
);
2268 png_chunk_benign_error(png_ptr
, "out of place");
2272 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_pCAL
) != 0)
2274 png_crc_finish(png_ptr
, length
);
2275 png_chunk_benign_error(png_ptr
, "duplicate");
2279 png_debug1(2, "Allocating and reading pCAL chunk data (%u bytes)",
2282 buffer
= png_read_buffer(png_ptr
, length
+1, 2/*silent*/);
2286 png_crc_finish(png_ptr
, length
);
2287 png_chunk_benign_error(png_ptr
, "out of memory");
2291 png_crc_read(png_ptr
, buffer
, length
);
2293 if (png_crc_finish(png_ptr
, 0) != 0)
2296 buffer
[length
] = 0; /* Null terminate the last string */
2298 png_debug(3, "Finding end of pCAL purpose string");
2299 for (buf
= buffer
; *buf
; buf
++)
2302 endptr
= buffer
+ length
;
2304 /* We need to have at least 12 bytes after the purpose string
2305 * in order to get the parameter information.
2307 if (endptr
- buf
<= 12)
2309 png_chunk_benign_error(png_ptr
, "invalid");
2313 png_debug(3, "Reading pCAL X0, X1, type, nparams, and units");
2314 X0
= png_get_int_32((png_bytep
)buf
+1);
2315 X1
= png_get_int_32((png_bytep
)buf
+5);
2320 png_debug(3, "Checking pCAL equation type and number of parameters");
2321 /* Check that we have the right number of parameters for known
2324 if ((type
== PNG_EQUATION_LINEAR
&& nparams
!= 2) ||
2325 (type
== PNG_EQUATION_BASE_E
&& nparams
!= 3) ||
2326 (type
== PNG_EQUATION_ARBITRARY
&& nparams
!= 3) ||
2327 (type
== PNG_EQUATION_HYPERBOLIC
&& nparams
!= 4))
2329 png_chunk_benign_error(png_ptr
, "invalid parameter count");
2333 else if (type
>= PNG_EQUATION_LAST
)
2335 png_chunk_benign_error(png_ptr
, "unrecognized equation type");
2338 for (buf
= units
; *buf
; buf
++)
2339 /* Empty loop to move past the units string. */ ;
2341 png_debug(3, "Allocating pCAL parameters array");
2343 params
= png_voidcast(png_charpp
, png_malloc_warn(png_ptr
,
2344 nparams
* (sizeof (png_charp
))));
2348 png_chunk_benign_error(png_ptr
, "out of memory");
2352 /* Get pointers to the start of each parameter string. */
2353 for (i
= 0; i
< nparams
; i
++)
2355 buf
++; /* Skip the null string terminator from previous parameter. */
2357 png_debug1(3, "Reading pCAL parameter %d", i
);
2359 for (params
[i
] = (png_charp
)buf
; buf
<= endptr
&& *buf
!= 0; buf
++)
2360 /* Empty loop to move past each parameter string */ ;
2362 /* Make sure we haven't run out of data yet */
2365 png_free(png_ptr
, params
);
2366 png_chunk_benign_error(png_ptr
, "invalid data");
2371 png_set_pCAL(png_ptr
, info_ptr
, (png_charp
)buffer
, X0
, X1
, type
, nparams
,
2372 (png_charp
)units
, params
);
2374 png_free(png_ptr
, params
);
2378 #ifdef PNG_READ_sCAL_SUPPORTED
2379 /* Read the sCAL chunk */
2381 png_handle_sCAL(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2387 png_debug(1, "in png_handle_sCAL");
2389 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2390 png_chunk_error(png_ptr
, "missing IHDR");
2392 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2394 png_crc_finish(png_ptr
, length
);
2395 png_chunk_benign_error(png_ptr
, "out of place");
2399 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_sCAL
) != 0)
2401 png_crc_finish(png_ptr
, length
);
2402 png_chunk_benign_error(png_ptr
, "duplicate");
2406 /* Need unit type, width, \0, height: minimum 4 bytes */
2407 else if (length
< 4)
2409 png_crc_finish(png_ptr
, length
);
2410 png_chunk_benign_error(png_ptr
, "invalid");
2414 png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)",
2417 buffer
= png_read_buffer(png_ptr
, length
+1, 2/*silent*/);
2421 png_chunk_benign_error(png_ptr
, "out of memory");
2422 png_crc_finish(png_ptr
, length
);
2426 png_crc_read(png_ptr
, buffer
, length
);
2427 buffer
[length
] = 0; /* Null terminate the last string */
2429 if (png_crc_finish(png_ptr
, 0) != 0)
2432 /* Validate the unit. */
2433 if (buffer
[0] != 1 && buffer
[0] != 2)
2435 png_chunk_benign_error(png_ptr
, "invalid unit");
2439 /* Validate the ASCII numbers, need two ASCII numbers separated by
2440 * a '\0' and they need to fit exactly in the chunk data.
2445 if (png_check_fp_number((png_const_charp
)buffer
, length
, &state
, &i
) == 0 ||
2446 i
>= length
|| buffer
[i
++] != 0)
2447 png_chunk_benign_error(png_ptr
, "bad width format");
2449 else if (PNG_FP_IS_POSITIVE(state
) == 0)
2450 png_chunk_benign_error(png_ptr
, "non-positive width");
2457 if (png_check_fp_number((png_const_charp
)buffer
, length
,
2458 &state
, &i
) == 0 || i
!= length
)
2459 png_chunk_benign_error(png_ptr
, "bad height format");
2461 else if (PNG_FP_IS_POSITIVE(state
) == 0)
2462 png_chunk_benign_error(png_ptr
, "non-positive height");
2465 /* This is the (only) success case. */
2466 png_set_sCAL_s(png_ptr
, info_ptr
, buffer
[0],
2467 (png_charp
)buffer
+1, (png_charp
)buffer
+heighti
);
2472 #ifdef PNG_READ_tIME_SUPPORTED
2474 png_handle_tIME(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2479 png_debug(1, "in png_handle_tIME");
2481 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2482 png_chunk_error(png_ptr
, "missing IHDR");
2484 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_tIME
) != 0)
2486 png_crc_finish(png_ptr
, length
);
2487 png_chunk_benign_error(png_ptr
, "duplicate");
2491 if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2492 png_ptr
->mode
|= PNG_AFTER_IDAT
;
2496 png_crc_finish(png_ptr
, length
);
2497 png_chunk_benign_error(png_ptr
, "invalid");
2501 png_crc_read(png_ptr
, buf
, 7);
2503 if (png_crc_finish(png_ptr
, 0) != 0)
2506 mod_time
.second
= buf
[6];
2507 mod_time
.minute
= buf
[5];
2508 mod_time
.hour
= buf
[4];
2509 mod_time
.day
= buf
[3];
2510 mod_time
.month
= buf
[2];
2511 mod_time
.year
= png_get_uint_16(buf
);
2513 png_set_tIME(png_ptr
, info_ptr
, &mod_time
);
2517 #ifdef PNG_READ_tEXt_SUPPORTED
2518 /* Note: this does not properly handle chunks that are > 64K under DOS */
2520 png_handle_tEXt(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2526 png_uint_32 skip
= 0;
2528 png_debug(1, "in png_handle_tEXt");
2530 #ifdef PNG_USER_LIMITS_SUPPORTED
2531 if (png_ptr
->user_chunk_cache_max
!= 0)
2533 if (png_ptr
->user_chunk_cache_max
== 1)
2535 png_crc_finish(png_ptr
, length
);
2539 if (--png_ptr
->user_chunk_cache_max
== 1)
2541 png_crc_finish(png_ptr
, length
);
2542 png_chunk_benign_error(png_ptr
, "no space in chunk cache");
2548 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2549 png_chunk_error(png_ptr
, "missing IHDR");
2551 if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2552 png_ptr
->mode
|= PNG_AFTER_IDAT
;
2554 #ifdef PNG_MAX_MALLOC_64K
2555 if (length
> 65535U)
2557 png_crc_finish(png_ptr
, length
);
2558 png_chunk_benign_error(png_ptr
, "too large to fit in memory");
2563 buffer
= png_read_buffer(png_ptr
, length
+1, 1/*warn*/);
2567 png_chunk_benign_error(png_ptr
, "out of memory");
2571 png_crc_read(png_ptr
, buffer
, length
);
2573 if (png_crc_finish(png_ptr
, skip
) != 0)
2576 key
= (png_charp
)buffer
;
2579 for (text
= key
; *text
; text
++)
2580 /* Empty loop to find end of key */ ;
2582 if (text
!= key
+ length
)
2585 text_info
.compression
= PNG_TEXT_COMPRESSION_NONE
;
2586 text_info
.key
= key
;
2587 text_info
.lang
= NULL
;
2588 text_info
.lang_key
= NULL
;
2589 text_info
.itxt_length
= 0;
2590 text_info
.text
= text
;
2591 text_info
.text_length
= strlen(text
);
2593 if (png_set_text_2(png_ptr
, info_ptr
, &text_info
, 1) != 0)
2594 png_warning(png_ptr
, "Insufficient memory to process text chunk");
2598 #ifdef PNG_READ_zTXt_SUPPORTED
2599 /* Note: this does not correctly handle chunks that are > 64K under DOS */
2601 png_handle_zTXt(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2603 png_const_charp errmsg
= NULL
;
2605 png_uint_32 keyword_length
;
2607 png_debug(1, "in png_handle_zTXt");
2609 #ifdef PNG_USER_LIMITS_SUPPORTED
2610 if (png_ptr
->user_chunk_cache_max
!= 0)
2612 if (png_ptr
->user_chunk_cache_max
== 1)
2614 png_crc_finish(png_ptr
, length
);
2618 if (--png_ptr
->user_chunk_cache_max
== 1)
2620 png_crc_finish(png_ptr
, length
);
2621 png_chunk_benign_error(png_ptr
, "no space in chunk cache");
2627 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2628 png_chunk_error(png_ptr
, "missing IHDR");
2630 if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2631 png_ptr
->mode
|= PNG_AFTER_IDAT
;
2633 /* Note, "length" is sufficient here; we won't be adding
2634 * a null terminator later.
2636 buffer
= png_read_buffer(png_ptr
, length
, 2/*silent*/);
2640 png_crc_finish(png_ptr
, length
);
2641 png_chunk_benign_error(png_ptr
, "out of memory");
2645 png_crc_read(png_ptr
, buffer
, length
);
2647 if (png_crc_finish(png_ptr
, 0) != 0)
2650 /* TODO: also check that the keyword contents match the spec! */
2651 for (keyword_length
= 0;
2652 keyword_length
< length
&& buffer
[keyword_length
] != 0;
2654 /* Empty loop to find end of name */ ;
2656 if (keyword_length
> 79 || keyword_length
< 1)
2657 errmsg
= "bad keyword";
2659 /* zTXt must have some LZ data after the keyword, although it may expand to
2660 * zero bytes; we need a '\0' at the end of the keyword, the compression type
2663 else if (keyword_length
+ 3 > length
)
2664 errmsg
= "truncated";
2666 else if (buffer
[keyword_length
+1] != PNG_COMPRESSION_TYPE_BASE
)
2667 errmsg
= "unknown compression type";
2671 png_alloc_size_t uncompressed_length
= PNG_SIZE_MAX
;
2673 /* TODO: at present png_decompress_chunk imposes a single application
2674 * level memory limit, this should be split to different values for iCCP
2677 if (png_decompress_chunk(png_ptr
, length
, keyword_length
+2,
2678 &uncompressed_length
, 1/*terminate*/) == Z_STREAM_END
)
2682 if (png_ptr
->read_buffer
== NULL
)
2683 errmsg
="Read failure in png_handle_zTXt";
2686 /* It worked; png_ptr->read_buffer now looks like a tEXt chunk
2687 * except for the extra compression type byte and the fact that
2688 * it isn't necessarily '\0' terminated.
2690 buffer
= png_ptr
->read_buffer
;
2691 buffer
[uncompressed_length
+(keyword_length
+2)] = 0;
2693 text
.compression
= PNG_TEXT_COMPRESSION_zTXt
;
2694 text
.key
= (png_charp
)buffer
;
2695 text
.text
= (png_charp
)(buffer
+ keyword_length
+2);
2696 text
.text_length
= uncompressed_length
;
2697 text
.itxt_length
= 0;
2699 text
.lang_key
= NULL
;
2701 if (png_set_text_2(png_ptr
, info_ptr
, &text
, 1) != 0)
2702 errmsg
= "insufficient memory";
2707 errmsg
= png_ptr
->zstream
.msg
;
2711 png_chunk_benign_error(png_ptr
, errmsg
);
2715 #ifdef PNG_READ_iTXt_SUPPORTED
2716 /* Note: this does not correctly handle chunks that are > 64K under DOS */
2718 png_handle_iTXt(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2720 png_const_charp errmsg
= NULL
;
2722 png_uint_32 prefix_length
;
2724 png_debug(1, "in png_handle_iTXt");
2726 #ifdef PNG_USER_LIMITS_SUPPORTED
2727 if (png_ptr
->user_chunk_cache_max
!= 0)
2729 if (png_ptr
->user_chunk_cache_max
== 1)
2731 png_crc_finish(png_ptr
, length
);
2735 if (--png_ptr
->user_chunk_cache_max
== 1)
2737 png_crc_finish(png_ptr
, length
);
2738 png_chunk_benign_error(png_ptr
, "no space in chunk cache");
2744 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2745 png_chunk_error(png_ptr
, "missing IHDR");
2747 if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2748 png_ptr
->mode
|= PNG_AFTER_IDAT
;
2750 buffer
= png_read_buffer(png_ptr
, length
+1, 1/*warn*/);
2754 png_crc_finish(png_ptr
, length
);
2755 png_chunk_benign_error(png_ptr
, "out of memory");
2759 png_crc_read(png_ptr
, buffer
, length
);
2761 if (png_crc_finish(png_ptr
, 0) != 0)
2764 /* First the keyword. */
2765 for (prefix_length
=0;
2766 prefix_length
< length
&& buffer
[prefix_length
] != 0;
2770 /* Perform a basic check on the keyword length here. */
2771 if (prefix_length
> 79 || prefix_length
< 1)
2772 errmsg
= "bad keyword";
2774 /* Expect keyword, compression flag, compression type, language, translated
2775 * keyword (both may be empty but are 0 terminated) then the text, which may
2778 else if (prefix_length
+ 5 > length
)
2779 errmsg
= "truncated";
2781 else if (buffer
[prefix_length
+1] == 0 ||
2782 (buffer
[prefix_length
+1] == 1 &&
2783 buffer
[prefix_length
+2] == PNG_COMPRESSION_TYPE_BASE
))
2785 int compressed
= buffer
[prefix_length
+1] != 0;
2786 png_uint_32 language_offset
, translated_keyword_offset
;
2787 png_alloc_size_t uncompressed_length
= 0;
2789 /* Now the language tag */
2791 language_offset
= prefix_length
;
2793 for (; prefix_length
< length
&& buffer
[prefix_length
] != 0;
2797 /* WARNING: the length may be invalid here, this is checked below. */
2798 translated_keyword_offset
= ++prefix_length
;
2800 for (; prefix_length
< length
&& buffer
[prefix_length
] != 0;
2804 /* prefix_length should now be at the trailing '\0' of the translated
2805 * keyword, but it may already be over the end. None of this arithmetic
2806 * can overflow because chunks are at most 2^31 bytes long, but on 16-bit
2807 * systems the available allocation may overflow.
2811 if (compressed
== 0 && prefix_length
<= length
)
2812 uncompressed_length
= length
- prefix_length
;
2814 else if (compressed
!= 0 && prefix_length
< length
)
2816 uncompressed_length
= PNG_SIZE_MAX
;
2818 /* TODO: at present png_decompress_chunk imposes a single application
2819 * level memory limit, this should be split to different values for
2820 * iCCP and text chunks.
2822 if (png_decompress_chunk(png_ptr
, length
, prefix_length
,
2823 &uncompressed_length
, 1/*terminate*/) == Z_STREAM_END
)
2824 buffer
= png_ptr
->read_buffer
;
2827 errmsg
= png_ptr
->zstream
.msg
;
2831 errmsg
= "truncated";
2837 buffer
[uncompressed_length
+prefix_length
] = 0;
2839 if (compressed
== 0)
2840 text
.compression
= PNG_ITXT_COMPRESSION_NONE
;
2843 text
.compression
= PNG_ITXT_COMPRESSION_zTXt
;
2845 text
.key
= (png_charp
)buffer
;
2846 text
.lang
= (png_charp
)buffer
+ language_offset
;
2847 text
.lang_key
= (png_charp
)buffer
+ translated_keyword_offset
;
2848 text
.text
= (png_charp
)buffer
+ prefix_length
;
2849 text
.text_length
= 0;
2850 text
.itxt_length
= uncompressed_length
;
2852 if (png_set_text_2(png_ptr
, info_ptr
, &text
, 1) != 0)
2853 errmsg
= "insufficient memory";
2858 errmsg
= "bad compression info";
2861 png_chunk_benign_error(png_ptr
, errmsg
);
2865 #ifdef PNG_READ_APNG_SUPPORTED
2867 png_handle_acTL(png_structp png_ptr
, png_infop info_ptr
, png_uint_32 length
)
2870 png_uint_32 num_frames
;
2871 png_uint_32 num_plays
;
2874 png_debug(1, "in png_handle_acTL");
2876 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2878 png_error(png_ptr
, "Missing IHDR before acTL");
2880 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2882 png_warning(png_ptr
, "Invalid acTL after IDAT skipped");
2883 png_crc_finish(png_ptr
, length
);
2886 else if ((png_ptr
->mode
& PNG_HAVE_acTL
) != 0)
2888 png_warning(png_ptr
, "Duplicate acTL skipped");
2889 png_crc_finish(png_ptr
, length
);
2892 else if (length
!= 8)
2894 png_warning(png_ptr
, "acTL with invalid length skipped");
2895 png_crc_finish(png_ptr
, length
);
2899 png_crc_read(png_ptr
, data
, 8);
2900 png_crc_finish(png_ptr
, 0);
2902 num_frames
= png_get_uint_31(png_ptr
, data
);
2903 num_plays
= png_get_uint_31(png_ptr
, data
+ 4);
2905 /* the set function will do error checking on num_frames */
2906 didSet
= png_set_acTL(png_ptr
, info_ptr
, num_frames
, num_plays
);
2908 png_ptr
->mode
|= PNG_HAVE_acTL
;
2912 png_handle_fcTL(png_structp png_ptr
, png_infop info_ptr
, png_uint_32 length
)
2917 png_uint_32 x_offset
;
2918 png_uint_32 y_offset
;
2919 png_uint_16 delay_num
;
2920 png_uint_16 delay_den
;
2921 png_byte dispose_op
;
2924 png_debug(1, "in png_handle_fcTL");
2926 png_ensure_sequence_number(png_ptr
, length
);
2928 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2930 png_error(png_ptr
, "Missing IHDR before fcTL");
2932 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2934 /* for any frames other then the first this message may be misleading,
2935 * but correct. PNG_HAVE_IDAT is unset before the frame head is read
2936 * i can't think of a better message */
2937 png_warning(png_ptr
, "Invalid fcTL after IDAT skipped");
2938 png_crc_finish(png_ptr
, length
-4);
2941 else if ((png_ptr
->mode
& PNG_HAVE_fcTL
) != 0)
2943 png_warning(png_ptr
, "Duplicate fcTL within one frame skipped");
2944 png_crc_finish(png_ptr
, length
-4);
2947 else if (length
!= 26)
2949 png_warning(png_ptr
, "fcTL with invalid length skipped");
2950 png_crc_finish(png_ptr
, length
-4);
2954 png_crc_read(png_ptr
, data
, 22);
2955 png_crc_finish(png_ptr
, 0);
2957 width
= png_get_uint_31(png_ptr
, data
);
2958 height
= png_get_uint_31(png_ptr
, data
+ 4);
2959 x_offset
= png_get_uint_31(png_ptr
, data
+ 8);
2960 y_offset
= png_get_uint_31(png_ptr
, data
+ 12);
2961 delay_num
= png_get_uint_16(data
+ 16);
2962 delay_den
= png_get_uint_16(data
+ 18);
2963 dispose_op
= data
[20];
2964 blend_op
= data
[21];
2966 if (png_ptr
->num_frames_read
== 0 && (x_offset
!= 0 || y_offset
!= 0))
2968 png_warning(png_ptr
, "fcTL for the first frame must have zero offset");
2972 if (info_ptr
!= NULL
)
2974 if (png_ptr
->num_frames_read
== 0 &&
2975 (width
!= info_ptr
->width
|| height
!= info_ptr
->height
))
2977 png_warning(png_ptr
, "size in first frame's fcTL must match "
2978 "the size in IHDR");
2982 /* The set function will do more error checking */
2983 png_set_next_frame_fcTL(png_ptr
, info_ptr
, width
, height
,
2984 x_offset
, y_offset
, delay_num
, delay_den
,
2985 dispose_op
, blend_op
);
2987 png_read_reinit(png_ptr
, info_ptr
);
2989 png_ptr
->mode
|= PNG_HAVE_fcTL
;
2994 png_have_info(png_structp png_ptr
, png_infop info_ptr
)
2996 if ((info_ptr
->valid
& PNG_INFO_acTL
) != 0 &&
2997 (info_ptr
->valid
& PNG_INFO_fcTL
) == 0)
2999 png_ptr
->apng_flags
|= PNG_FIRST_FRAME_HIDDEN
;
3000 info_ptr
->num_frames
++;
3005 png_handle_fdAT(png_structp png_ptr
, png_infop info_ptr
, png_uint_32 length
)
3007 png_ensure_sequence_number(png_ptr
, length
);
3009 /* This function is only called from png_read_end(), png_read_info(),
3010 * and png_push_read_chunk() which means that:
3011 * - the user doesn't want to read this frame
3012 * - or this is an out-of-place fdAT
3013 * in either case it is safe to ignore the chunk with a warning */
3014 png_warning(png_ptr
, "ignoring fdAT chunk");
3015 png_crc_finish(png_ptr
, length
- 4);
3016 PNG_UNUSED(info_ptr
)
3020 png_ensure_sequence_number(png_structp png_ptr
, png_uint_32 length
)
3023 png_uint_32 sequence_number
;
3026 png_error(png_ptr
, "invalid fcTL or fdAT chunk found");
3028 png_crc_read(png_ptr
, data
, 4);
3029 sequence_number
= png_get_uint_31(png_ptr
, data
);
3031 if (sequence_number
!= png_ptr
->next_seq_num
)
3032 png_error(png_ptr
, "fcTL or fdAT chunk with out-of-order sequence "
3035 png_ptr
->next_seq_num
++;
3037 #endif /* READ_APNG */
3039 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
3040 /* Utility function for png_handle_unknown; set up png_ptr::unknown_chunk */
3042 png_cache_unknown_chunk(png_structrp png_ptr
, png_uint_32 length
)
3044 png_alloc_size_t limit
= PNG_SIZE_MAX
;
3046 if (png_ptr
->unknown_chunk
.data
!= NULL
)
3048 png_free(png_ptr
, png_ptr
->unknown_chunk
.data
);
3049 png_ptr
->unknown_chunk
.data
= NULL
;
3052 # ifdef PNG_SET_USER_LIMITS_SUPPORTED
3053 if (png_ptr
->user_chunk_malloc_max
> 0 &&
3054 png_ptr
->user_chunk_malloc_max
< limit
)
3055 limit
= png_ptr
->user_chunk_malloc_max
;
3057 # elif PNG_USER_CHUNK_MALLOC_MAX > 0
3058 if (PNG_USER_CHUNK_MALLOC_MAX
< limit
)
3059 limit
= PNG_USER_CHUNK_MALLOC_MAX
;
3062 if (length
<= limit
)
3064 PNG_CSTRING_FROM_CHUNK(png_ptr
->unknown_chunk
.name
, png_ptr
->chunk_name
);
3065 /* The following is safe because of the PNG_SIZE_MAX init above */
3066 png_ptr
->unknown_chunk
.size
= (size_t)length
/*SAFE*/;
3067 /* 'mode' is a flag array, only the bottom four bits matter here */
3068 png_ptr
->unknown_chunk
.location
= (png_byte
)png_ptr
->mode
/*SAFE*/;
3071 png_ptr
->unknown_chunk
.data
= NULL
;
3075 /* Do a 'warn' here - it is handled below. */
3076 png_ptr
->unknown_chunk
.data
= png_voidcast(png_bytep
,
3077 png_malloc_warn(png_ptr
, length
));
3081 if (png_ptr
->unknown_chunk
.data
== NULL
&& length
> 0)
3083 /* This is benign because we clean up correctly */
3084 png_crc_finish(png_ptr
, length
);
3085 png_chunk_benign_error(png_ptr
, "unknown chunk exceeds memory limits");
3092 png_crc_read(png_ptr
, png_ptr
->unknown_chunk
.data
, length
);
3093 png_crc_finish(png_ptr
, 0);
3097 #endif /* READ_UNKNOWN_CHUNKS */
3099 /* Handle an unknown, or known but disabled, chunk */
3101 png_handle_unknown(png_structrp png_ptr
, png_inforp info_ptr
,
3102 png_uint_32 length
, int keep
)
3104 int handled
= 0; /* the chunk was handled */
3106 png_debug(1, "in png_handle_unknown");
3108 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
3109 /* NOTE: this code is based on the code in libpng-1.4.12 except for fixing
3110 * the bug which meant that setting a non-default behavior for a specific
3111 * chunk would be ignored (the default was always used unless a user
3112 * callback was installed).
3114 * 'keep' is the value from the png_chunk_unknown_handling, the setting for
3115 * this specific chunk_name, if PNG_HANDLE_AS_UNKNOWN_SUPPORTED, if not it
3116 * will always be PNG_HANDLE_CHUNK_AS_DEFAULT and it needs to be set here.
3117 * This is just an optimization to avoid multiple calls to the lookup
3120 # ifndef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
3121 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
3122 keep
= png_chunk_unknown_handling(png_ptr
, png_ptr
->chunk_name
);
3126 /* One of the following methods will read the chunk or skip it (at least one
3127 * of these is always defined because this is the only way to switch on
3128 * PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
3130 # ifdef PNG_READ_USER_CHUNKS_SUPPORTED
3131 /* The user callback takes precedence over the chunk keep value, but the
3132 * keep value is still required to validate a save of a critical chunk.
3134 if (png_ptr
->read_user_chunk_fn
!= NULL
)
3136 if (png_cache_unknown_chunk(png_ptr
, length
) != 0)
3138 /* Callback to user unknown chunk handler */
3139 int ret
= (*(png_ptr
->read_user_chunk_fn
))(png_ptr
,
3140 &png_ptr
->unknown_chunk
);
3143 * negative: An error occurred; png_chunk_error will be called.
3144 * zero: The chunk was not handled, the chunk will be discarded
3145 * unless png_set_keep_unknown_chunks has been used to set
3146 * a 'keep' behavior for this particular chunk, in which
3147 * case that will be used. A critical chunk will cause an
3148 * error at this point unless it is to be saved.
3149 * positive: The chunk was handled, libpng will ignore/discard it.
3152 png_chunk_error(png_ptr
, "error in user chunk");
3156 /* If the keep value is 'default' or 'never' override it, but
3157 * still error out on critical chunks unless the keep value is
3158 * 'always' While this is weird it is the behavior in 1.4.12.
3159 * A possible improvement would be to obey the value set for the
3160 * chunk, but this would be an API change that would probably
3161 * damage some applications.
3163 * The png_app_warning below catches the case that matters, where
3164 * the application has not set specific save or ignore for this
3165 * chunk or global save or ignore.
3167 if (keep
< PNG_HANDLE_CHUNK_IF_SAFE
)
3169 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
3170 if (png_ptr
->unknown_default
< PNG_HANDLE_CHUNK_IF_SAFE
)
3172 png_chunk_warning(png_ptr
, "Saving unknown chunk:");
3173 png_app_warning(png_ptr
,
3174 "forcing save of an unhandled chunk;"
3175 " please call png_set_keep_unknown_chunks");
3176 /* with keep = PNG_HANDLE_CHUNK_IF_SAFE */
3179 keep
= PNG_HANDLE_CHUNK_IF_SAFE
;
3183 else /* chunk was handled */
3186 /* Critical chunks can be safely discarded at this point. */
3187 keep
= PNG_HANDLE_CHUNK_NEVER
;
3192 keep
= PNG_HANDLE_CHUNK_NEVER
; /* insufficient memory */
3196 /* Use the SAVE_UNKNOWN_CHUNKS code or skip the chunk */
3197 # endif /* READ_USER_CHUNKS */
3199 # ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
3201 /* keep is currently just the per-chunk setting, if there was no
3202 * setting change it to the global default now (not that this may
3203 * still be AS_DEFAULT) then obtain the cache of the chunk if required,
3204 * if not simply skip the chunk.
3206 if (keep
== PNG_HANDLE_CHUNK_AS_DEFAULT
)
3207 keep
= png_ptr
->unknown_default
;
3209 if (keep
== PNG_HANDLE_CHUNK_ALWAYS
||
3210 (keep
== PNG_HANDLE_CHUNK_IF_SAFE
&&
3211 PNG_CHUNK_ANCILLARY(png_ptr
->chunk_name
)))
3213 if (png_cache_unknown_chunk(png_ptr
, length
) == 0)
3214 keep
= PNG_HANDLE_CHUNK_NEVER
;
3218 png_crc_finish(png_ptr
, length
);
3221 # ifndef PNG_READ_USER_CHUNKS_SUPPORTED
3222 # error no method to support READ_UNKNOWN_CHUNKS
3226 /* If here there is no read callback pointer set and no support is
3227 * compiled in to just save the unknown chunks, so simply skip this
3228 * chunk. If 'keep' is something other than AS_DEFAULT or NEVER then
3229 * the app has erroneously asked for unknown chunk saving when there
3232 if (keep
> PNG_HANDLE_CHUNK_NEVER
)
3233 png_app_error(png_ptr
, "no unknown chunk support available");
3235 png_crc_finish(png_ptr
, length
);
3239 # ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
3240 /* Now store the chunk in the chunk list if appropriate, and if the limits
3243 if (keep
== PNG_HANDLE_CHUNK_ALWAYS
||
3244 (keep
== PNG_HANDLE_CHUNK_IF_SAFE
&&
3245 PNG_CHUNK_ANCILLARY(png_ptr
->chunk_name
)))
3247 # ifdef PNG_USER_LIMITS_SUPPORTED
3248 switch (png_ptr
->user_chunk_cache_max
)
3251 png_ptr
->user_chunk_cache_max
= 1;
3252 png_chunk_benign_error(png_ptr
, "no space in chunk cache");
3255 /* NOTE: prior to 1.6.0 this case resulted in an unknown critical
3256 * chunk being skipped, now there will be a hard error below.
3260 default: /* not at limit */
3261 --(png_ptr
->user_chunk_cache_max
);
3263 case 0: /* no limit */
3264 # endif /* USER_LIMITS */
3265 /* Here when the limit isn't reached or when limits are compiled
3266 * out; store the chunk.
3268 png_set_unknown_chunks(png_ptr
, info_ptr
,
3269 &png_ptr
->unknown_chunk
, 1);
3271 # ifdef PNG_USER_LIMITS_SUPPORTED
3276 # else /* no store support: the chunk must be handled by the user callback */
3277 PNG_UNUSED(info_ptr
)
3280 /* Regardless of the error handling below the cached data (if any) can be
3281 * freed now. Notice that the data is not freed if there is a png_error, but
3282 * it will be freed by destroy_read_struct.
3284 if (png_ptr
->unknown_chunk
.data
!= NULL
)
3285 png_free(png_ptr
, png_ptr
->unknown_chunk
.data
);
3286 png_ptr
->unknown_chunk
.data
= NULL
;
3288 #else /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */
3289 /* There is no support to read an unknown chunk, so just skip it. */
3290 png_crc_finish(png_ptr
, length
);
3291 PNG_UNUSED(info_ptr
)
3293 #endif /* !READ_UNKNOWN_CHUNKS */
3295 /* Check for unhandled critical chunks */
3296 if (handled
== 0 && PNG_CHUNK_CRITICAL(png_ptr
->chunk_name
))
3297 png_chunk_error(png_ptr
, "unhandled critical chunk");
3300 /* This function is called to verify that a chunk name is valid.
3301 * This function can't have the "critical chunk check" incorporated
3302 * into it, since in the future we will need to be able to call user
3303 * functions to handle unknown critical chunks after we check that
3304 * the chunk name itself is valid.
3307 /* Bit hacking: the test for an invalid byte in the 4 byte chunk name is:
3309 * ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
3313 png_check_chunk_name(png_const_structrp png_ptr
, png_uint_32 chunk_name
)
3316 png_uint_32 cn
=chunk_name
;
3318 png_debug(1, "in png_check_chunk_name");
3320 for (i
=1; i
<=4; ++i
)
3324 if (c
< 65 || c
> 122 || (c
> 90 && c
< 97))
3325 png_chunk_error(png_ptr
, "invalid chunk type");
3332 png_check_chunk_length(png_const_structrp png_ptr
, png_uint_32 length
)
3334 png_alloc_size_t limit
= PNG_UINT_31_MAX
;
3336 # ifdef PNG_SET_USER_LIMITS_SUPPORTED
3337 if (png_ptr
->user_chunk_malloc_max
> 0 &&
3338 png_ptr
->user_chunk_malloc_max
< limit
)
3339 limit
= png_ptr
->user_chunk_malloc_max
;
3340 # elif PNG_USER_CHUNK_MALLOC_MAX > 0
3341 if (PNG_USER_CHUNK_MALLOC_MAX
< limit
)
3342 limit
= PNG_USER_CHUNK_MALLOC_MAX
;
3344 #ifdef PNG_READ_APNG_SUPPORTED
3345 if (png_ptr
->chunk_name
== png_IDAT
|| png_ptr
->chunk_name
== png_fdAT
)
3347 if (png_ptr
->chunk_name
== png_IDAT
)
3350 png_alloc_size_t idat_limit
= PNG_UINT_31_MAX
;
3352 (size_t)png_ptr
->width
3353 * (size_t)png_ptr
->channels
3354 * (png_ptr
->bit_depth
> 8? 2: 1)
3356 + (png_ptr
->interlaced
? 6: 0);
3357 if (png_ptr
->height
> PNG_UINT_32_MAX
/row_factor
)
3358 idat_limit
= PNG_UINT_31_MAX
;
3360 idat_limit
= png_ptr
->height
* row_factor
;
3361 row_factor
= row_factor
> 32566? 32566 : row_factor
;
3362 idat_limit
+= 6 + 5*(idat_limit
/row_factor
+1); /* zlib+deflate overhead */
3363 idat_limit
=idat_limit
< PNG_UINT_31_MAX
? idat_limit
: PNG_UINT_31_MAX
;
3364 limit
= limit
< idat_limit
? idat_limit
: limit
;
3369 png_debug2(0," length = %lu, limit = %lu",
3370 (unsigned long)length
,(unsigned long)limit
);
3371 png_benign_error(png_ptr
, "chunk data is too large");
3375 /* Combines the row recently read in with the existing pixels in the row. This
3376 * routine takes care of alpha and transparency if requested. This routine also
3377 * handles the two methods of progressive display of interlaced images,
3378 * depending on the 'display' value; if 'display' is true then the whole row
3379 * (dp) is filled from the start by replicating the available pixels. If
3380 * 'display' is false only those pixels present in the pass are filled in.
3383 png_combine_row(png_const_structrp png_ptr
, png_bytep dp
, int display
)
3385 unsigned int pixel_depth
= png_ptr
->transformed_pixel_depth
;
3386 png_const_bytep sp
= png_ptr
->row_buf
+ 1;
3387 png_alloc_size_t row_width
= png_ptr
->width
;
3388 unsigned int pass
= png_ptr
->pass
;
3389 png_bytep end_ptr
= 0;
3390 png_byte end_byte
= 0;
3391 unsigned int end_mask
;
3393 png_debug(1, "in png_combine_row");
3395 /* Added in 1.5.6: it should not be possible to enter this routine until at
3396 * least one row has been read from the PNG data and transformed.
3398 if (pixel_depth
== 0)
3399 png_error(png_ptr
, "internal row logic error");
3401 /* Added in 1.5.4: the pixel depth should match the information returned by
3402 * any call to png_read_update_info at this point. Do not continue if we got
3405 if (png_ptr
->info_rowbytes
!= 0 && png_ptr
->info_rowbytes
!=
3406 PNG_ROWBYTES(pixel_depth
, row_width
))
3407 png_error(png_ptr
, "internal row size calculation error");
3409 /* Don't expect this to ever happen: */
3411 png_error(png_ptr
, "internal row width error");
3413 /* Preserve the last byte in cases where only part of it will be overwritten,
3414 * the multiply below may overflow, we don't care because ANSI-C guarantees
3415 * we get the low bits.
3417 end_mask
= (pixel_depth
* row_width
) & 7;
3420 /* end_ptr == NULL is a flag to say do nothing */
3421 end_ptr
= dp
+ PNG_ROWBYTES(pixel_depth
, row_width
) - 1;
3422 end_byte
= *end_ptr
;
3423 # ifdef PNG_READ_PACKSWAP_SUPPORTED
3424 if ((png_ptr
->transformations
& PNG_PACKSWAP
) != 0)
3425 /* little-endian byte */
3426 end_mask
= (unsigned int)(0xff << end_mask
);
3428 else /* big-endian byte */
3430 end_mask
= 0xff >> end_mask
;
3431 /* end_mask is now the bits to *keep* from the destination row */
3434 /* For non-interlaced images this reduces to a memcpy(). A memcpy()
3435 * will also happen if interlacing isn't supported or if the application
3436 * does not call png_set_interlace_handling(). In the latter cases the
3437 * caller just gets a sequence of the unexpanded rows from each interlace
3440 #ifdef PNG_READ_INTERLACING_SUPPORTED
3441 if (png_ptr
->interlaced
!= 0 &&
3442 (png_ptr
->transformations
& PNG_INTERLACE
) != 0 &&
3443 pass
< 6 && (display
== 0 ||
3444 /* The following copies everything for 'display' on passes 0, 2 and 4. */
3445 (display
== 1 && (pass
& 1) != 0)))
3447 /* Narrow images may have no bits in a pass; the caller should handle
3448 * this, but this test is cheap:
3450 if (row_width
<= PNG_PASS_START_COL(pass
))
3453 if (pixel_depth
< 8)
3455 /* For pixel depths up to 4 bpp the 8-pixel mask can be expanded to fit
3456 * into 32 bits, then a single loop over the bytes using the four byte
3457 * values in the 32-bit mask can be used. For the 'display' option the
3458 * expanded mask may also not require any masking within a byte. To
3459 * make this work the PACKSWAP option must be taken into account - it
3460 * simply requires the pixels to be reversed in each byte.
3462 * The 'regular' case requires a mask for each of the first 6 passes,
3463 * the 'display' case does a copy for the even passes in the range
3464 * 0..6. This has already been handled in the test above.
3466 * The masks are arranged as four bytes with the first byte to use in
3467 * the lowest bits (little-endian) regardless of the order (PACKSWAP or
3468 * not) of the pixels in each byte.
3470 * NOTE: the whole of this logic depends on the caller of this function
3471 * only calling it on rows appropriate to the pass. This function only
3472 * understands the 'x' logic; the 'y' logic is handled by the caller.
3474 * The following defines allow generation of compile time constant bit
3475 * masks for each pixel depth and each possibility of swapped or not
3476 * swapped bytes. Pass 'p' is in the range 0..6; 'x', a pixel index,
3477 * is in the range 0..7; and the result is 1 if the pixel is to be
3478 * copied in the pass, 0 if not. 'S' is for the sparkle method, 'B'
3479 * for the block method.
3481 * With some compilers a compile time expression of the general form:
3483 * (shift >= 32) ? (a >> (shift-32)) : (b >> shift)
3485 * Produces warnings with values of 'shift' in the range 33 to 63
3486 * because the right hand side of the ?: expression is evaluated by
3487 * the compiler even though it isn't used. Microsoft Visual C (various
3488 * versions) and the Intel C compiler are known to do this. To avoid
3489 * this the following macros are used in 1.5.6. This is a temporary
3490 * solution to avoid destabilizing the code during the release process.
3492 # if PNG_USE_COMPILE_TIME_MASKS
3493 # define PNG_LSR(x,s) ((x)>>((s) & 0x1f))
3494 # define PNG_LSL(x,s) ((x)<<((s) & 0x1f))
3496 # define PNG_LSR(x,s) ((x)>>(s))
3497 # define PNG_LSL(x,s) ((x)<<(s))
3499 # define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\
3500 PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1)
3501 # define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\
3502 PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1)
3504 /* Return a mask for pass 'p' pixel 'x' at depth 'd'. The mask is
3505 * little endian - the first pixel is at bit 0 - however the extra
3506 * parameter 's' can be set to cause the mask position to be swapped
3507 * within each byte, to match the PNG format. This is done by XOR of
3508 * the shift with 7, 6 or 4 for bit depths 1, 2 and 4.
3510 # define PIXEL_MASK(p,x,d,s) \
3511 (PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0))))
3513 /* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask.
3515 # define S_MASKx(p,x,d,s) (S_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
3516 # define B_MASKx(p,x,d,s) (B_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
3518 /* Combine 8 of these to get the full mask. For the 1-bpp and 2-bpp
3519 * cases the result needs replicating, for the 4-bpp case the above
3520 * generates a full 32 bits.
3522 # define MASK_EXPAND(m,d) ((m)*((d)==1?0x01010101:((d)==2?0x00010001:1)))
3524 # define S_MASK(p,d,s) MASK_EXPAND(S_MASKx(p,0,d,s) + S_MASKx(p,1,d,s) +\
3525 S_MASKx(p,2,d,s) + S_MASKx(p,3,d,s) + S_MASKx(p,4,d,s) +\
3526 S_MASKx(p,5,d,s) + S_MASKx(p,6,d,s) + S_MASKx(p,7,d,s), d)
3528 # define B_MASK(p,d,s) MASK_EXPAND(B_MASKx(p,0,d,s) + B_MASKx(p,1,d,s) +\
3529 B_MASKx(p,2,d,s) + B_MASKx(p,3,d,s) + B_MASKx(p,4,d,s) +\
3530 B_MASKx(p,5,d,s) + B_MASKx(p,6,d,s) + B_MASKx(p,7,d,s), d)
3532 #if PNG_USE_COMPILE_TIME_MASKS
3533 /* Utility macros to construct all the masks for a depth/swap
3534 * combination. The 's' parameter says whether the format is PNG
3535 * (big endian bytes) or not. Only the three odd-numbered passes are
3536 * required for the display/block algorithm.
3538 # define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\
3539 S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) }
3541 # define B_MASKS(d,s) { B_MASK(1,d,s), B_MASK(3,d,s), B_MASK(5,d,s) }
3543 # define DEPTH_INDEX(d) ((d)==1?0:((d)==2?1:2))
3545 /* Hence the pre-compiled masks indexed by PACKSWAP (or not), depth and
3548 static const png_uint_32 row_mask
[2/*PACKSWAP*/][3/*depth*/][6] =
3550 /* Little-endian byte masks for PACKSWAP */
3551 { S_MASKS(1,0), S_MASKS(2,0), S_MASKS(4,0) },
3552 /* Normal (big-endian byte) masks - PNG format */
3553 { S_MASKS(1,1), S_MASKS(2,1), S_MASKS(4,1) }
3556 /* display_mask has only three entries for the odd passes, so index by
3559 static const png_uint_32 display_mask
[2][3][3] =
3561 /* Little-endian byte masks for PACKSWAP */
3562 { B_MASKS(1,0), B_MASKS(2,0), B_MASKS(4,0) },
3563 /* Normal (big-endian byte) masks - PNG format */
3564 { B_MASKS(1,1), B_MASKS(2,1), B_MASKS(4,1) }
3567 # define MASK(pass,depth,display,png)\
3568 ((display)?display_mask[png][DEPTH_INDEX(depth)][pass>>1]:\
3569 row_mask[png][DEPTH_INDEX(depth)][pass])
3571 #else /* !PNG_USE_COMPILE_TIME_MASKS */
3572 /* This is the runtime alternative: it seems unlikely that this will
3573 * ever be either smaller or faster than the compile time approach.
3575 # define MASK(pass,depth,display,png)\
3576 ((display)?B_MASK(pass,depth,png):S_MASK(pass,depth,png))
3577 #endif /* !USE_COMPILE_TIME_MASKS */
3579 /* Use the appropriate mask to copy the required bits. In some cases
3580 * the byte mask will be 0 or 0xff; optimize these cases. row_width is
3581 * the number of pixels, but the code copies bytes, so it is necessary
3582 * to special case the end.
3584 png_uint_32 pixels_per_byte
= 8 / pixel_depth
;
3587 # ifdef PNG_READ_PACKSWAP_SUPPORTED
3588 if ((png_ptr
->transformations
& PNG_PACKSWAP
) != 0)
3589 mask
= MASK(pass
, pixel_depth
, display
, 0);
3593 mask
= MASK(pass
, pixel_depth
, display
, 1);
3599 /* It doesn't matter in the following if png_uint_32 has more than
3600 * 32 bits because the high bits always match those in m<<24; it is,
3601 * however, essential to use OR here, not +, because of this.
3604 mask
= (m
>> 8) | (m
<< 24); /* rotate right to good compilers */
3607 if (m
!= 0) /* something to copy */
3610 *dp
= (png_byte
)((*dp
& ~m
) | (*sp
& m
));
3615 /* NOTE: this may overwrite the last byte with garbage if the image
3616 * is not an exact number of bytes wide; libpng has always done
3619 if (row_width
<= pixels_per_byte
)
3620 break; /* May need to restore part of the last byte */
3622 row_width
-= pixels_per_byte
;
3628 else /* pixel_depth >= 8 */
3630 unsigned int bytes_to_copy
, bytes_to_jump
;
3632 /* Validate the depth - it must be a multiple of 8 */
3633 if (pixel_depth
& 7)
3634 png_error(png_ptr
, "invalid user transform pixel depth");
3636 pixel_depth
>>= 3; /* now in bytes */
3637 row_width
*= pixel_depth
;
3639 /* Regardless of pass number the Adam 7 interlace always results in a
3640 * fixed number of pixels to copy then to skip. There may be a
3641 * different number of pixels to skip at the start though.
3644 unsigned int offset
= PNG_PASS_START_COL(pass
) * pixel_depth
;
3646 row_width
-= offset
;
3651 /* Work out the bytes to copy. */
3654 /* When doing the 'block' algorithm the pixel in the pass gets
3655 * replicated to adjacent pixels. This is why the even (0,2,4,6)
3656 * passes are skipped above - the entire expanded row is copied.
3658 bytes_to_copy
= (1<<((6-pass
)>>1)) * pixel_depth
;
3660 /* But don't allow this number to exceed the actual row width. */
3661 if (bytes_to_copy
> row_width
)
3662 bytes_to_copy
= (unsigned int)/*SAFE*/row_width
;
3665 else /* normal row; Adam7 only ever gives us one pixel to copy. */
3666 bytes_to_copy
= pixel_depth
;
3668 /* In Adam7 there is a constant offset between where the pixels go. */
3669 bytes_to_jump
= PNG_PASS_COL_OFFSET(pass
) * pixel_depth
;
3671 /* And simply copy these bytes. Some optimization is possible here,
3672 * depending on the value of 'bytes_to_copy'. Special case the low
3673 * byte counts, which we know to be frequent.
3675 * Notice that these cases all 'return' rather than 'break' - this
3676 * avoids an unnecessary test on whether to restore the last byte
3679 switch (bytes_to_copy
)
3686 if (row_width
<= bytes_to_jump
)
3689 dp
+= bytes_to_jump
;
3690 sp
+= bytes_to_jump
;
3691 row_width
-= bytes_to_jump
;
3695 /* There is a possibility of a partial copy at the end here; this
3696 * slows the code down somewhat.
3700 dp
[0] = sp
[0]; dp
[1] = sp
[1];
3702 if (row_width
<= bytes_to_jump
)
3705 sp
+= bytes_to_jump
;
3706 dp
+= bytes_to_jump
;
3707 row_width
-= bytes_to_jump
;
3709 while (row_width
> 1);
3711 /* And there can only be one byte left at this point: */
3716 /* This can only be the RGB case, so each copy is exactly one
3717 * pixel and it is not necessary to check for a partial copy.
3721 dp
[0] = sp
[0]; dp
[1] = sp
[1]; dp
[2] = sp
[2];
3723 if (row_width
<= bytes_to_jump
)
3726 sp
+= bytes_to_jump
;
3727 dp
+= bytes_to_jump
;
3728 row_width
-= bytes_to_jump
;
3732 #if PNG_ALIGN_TYPE != PNG_ALIGN_NONE
3733 /* Check for double byte alignment and, if possible, use a
3734 * 16-bit copy. Don't attempt this for narrow images - ones that
3735 * are less than an interlace panel wide. Don't attempt it for
3736 * wide bytes_to_copy either - use the memcpy there.
3738 if (bytes_to_copy
< 16 /*else use memcpy*/ &&
3739 png_isaligned(dp
, png_uint_16
) &&
3740 png_isaligned(sp
, png_uint_16
) &&
3741 bytes_to_copy
% (sizeof (png_uint_16
)) == 0 &&
3742 bytes_to_jump
% (sizeof (png_uint_16
)) == 0)
3744 /* Everything is aligned for png_uint_16 copies, but try for
3745 * png_uint_32 first.
3747 if (png_isaligned(dp
, png_uint_32
) &&
3748 png_isaligned(sp
, png_uint_32
) &&
3749 bytes_to_copy
% (sizeof (png_uint_32
)) == 0 &&
3750 bytes_to_jump
% (sizeof (png_uint_32
)) == 0)
3752 png_uint_32p dp32
= png_aligncast(png_uint_32p
,dp
);
3753 png_const_uint_32p sp32
= png_aligncastconst(
3754 png_const_uint_32p
, sp
);
3755 size_t skip
= (bytes_to_jump
-bytes_to_copy
) /
3756 (sizeof (png_uint_32
));
3760 size_t c
= bytes_to_copy
;
3764 c
-= (sizeof (png_uint_32
));
3768 if (row_width
<= bytes_to_jump
)
3773 row_width
-= bytes_to_jump
;
3775 while (bytes_to_copy
<= row_width
);
3777 /* Get to here when the row_width truncates the final copy.
3778 * There will be 1-3 bytes left to copy, so don't try the
3779 * 16-bit loop below.
3781 dp
= (png_bytep
)dp32
;
3782 sp
= (png_const_bytep
)sp32
;
3785 while (--row_width
> 0);
3789 /* Else do it in 16-bit quantities, but only if the size is
3794 png_uint_16p dp16
= png_aligncast(png_uint_16p
, dp
);
3795 png_const_uint_16p sp16
= png_aligncastconst(
3796 png_const_uint_16p
, sp
);
3797 size_t skip
= (bytes_to_jump
-bytes_to_copy
) /
3798 (sizeof (png_uint_16
));
3802 size_t c
= bytes_to_copy
;
3806 c
-= (sizeof (png_uint_16
));
3810 if (row_width
<= bytes_to_jump
)
3815 row_width
-= bytes_to_jump
;
3817 while (bytes_to_copy
<= row_width
);
3819 /* End of row - 1 byte left, bytes_to_copy > row_width: */
3820 dp
= (png_bytep
)dp16
;
3821 sp
= (png_const_bytep
)sp16
;
3824 while (--row_width
> 0);
3828 #endif /* ALIGN_TYPE code */
3830 /* The true default - use a memcpy: */
3833 memcpy(dp
, sp
, bytes_to_copy
);
3835 if (row_width
<= bytes_to_jump
)
3838 sp
+= bytes_to_jump
;
3839 dp
+= bytes_to_jump
;
3840 row_width
-= bytes_to_jump
;
3841 if (bytes_to_copy
> row_width
)
3842 bytes_to_copy
= (unsigned int)/*SAFE*/row_width
;
3847 } /* pixel_depth >= 8 */
3849 /* Here if pixel_depth < 8 to check 'end_ptr' below. */
3852 #endif /* READ_INTERLACING */
3854 /* If here then the switch above wasn't used so just memcpy the whole row
3855 * from the temporary row buffer (notice that this overwrites the end of the
3856 * destination row if it is a partial byte.)
3858 memcpy(dp
, sp
, PNG_ROWBYTES(pixel_depth
, row_width
));
3860 /* Restore the overwritten bits from the last byte if necessary. */
3861 if (end_ptr
!= NULL
)
3862 *end_ptr
= (png_byte
)((end_byte
& end_mask
) | (*end_ptr
& ~end_mask
));
3865 #ifdef PNG_READ_INTERLACING_SUPPORTED
3867 png_do_read_interlace(png_row_infop row_info
, png_bytep row
, int pass
,
3868 png_uint_32 transformations
/* Because these may affect the byte layout */)
3870 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
3871 /* Offset to next interlace block */
3872 static const unsigned int png_pass_inc
[7] = {8, 8, 4, 4, 2, 2, 1};
3874 png_debug(1, "in png_do_read_interlace");
3875 if (row
!= NULL
&& row_info
!= NULL
)
3877 png_uint_32 final_width
;
3879 final_width
= row_info
->width
* png_pass_inc
[pass
];
3881 switch (row_info
->pixel_depth
)
3885 png_bytep sp
= row
+ (size_t)((row_info
->width
- 1) >> 3);
3886 png_bytep dp
= row
+ (size_t)((final_width
- 1) >> 3);
3887 unsigned int sshift
, dshift
;
3888 unsigned int s_start
, s_end
;
3890 int jstop
= (int)png_pass_inc
[pass
];
3895 #ifdef PNG_READ_PACKSWAP_SUPPORTED
3896 if ((transformations
& PNG_PACKSWAP
) != 0)
3898 sshift
= ((row_info
->width
+ 7) & 0x07);
3899 dshift
= ((final_width
+ 7) & 0x07);
3908 sshift
= 7 - ((row_info
->width
+ 7) & 0x07);
3909 dshift
= 7 - ((final_width
+ 7) & 0x07);
3915 for (i
= 0; i
< row_info
->width
; i
++)
3917 v
= (png_byte
)((*sp
>> sshift
) & 0x01);
3918 for (j
= 0; j
< jstop
; j
++)
3920 unsigned int tmp
= *dp
& (0x7f7f >> (7 - dshift
));
3921 tmp
|= (unsigned int)(v
<< dshift
);
3922 *dp
= (png_byte
)(tmp
& 0xff);
3924 if (dshift
== s_end
)
3931 dshift
= (unsigned int)((int)dshift
+ s_inc
);
3934 if (sshift
== s_end
)
3941 sshift
= (unsigned int)((int)sshift
+ s_inc
);
3948 png_bytep sp
= row
+ (png_uint_32
)((row_info
->width
- 1) >> 2);
3949 png_bytep dp
= row
+ (png_uint_32
)((final_width
- 1) >> 2);
3950 unsigned int sshift
, dshift
;
3951 unsigned int s_start
, s_end
;
3953 int jstop
= (int)png_pass_inc
[pass
];
3956 #ifdef PNG_READ_PACKSWAP_SUPPORTED
3957 if ((transformations
& PNG_PACKSWAP
) != 0)
3959 sshift
= (((row_info
->width
+ 3) & 0x03) << 1);
3960 dshift
= (((final_width
+ 3) & 0x03) << 1);
3969 sshift
= ((3 - ((row_info
->width
+ 3) & 0x03)) << 1);
3970 dshift
= ((3 - ((final_width
+ 3) & 0x03)) << 1);
3976 for (i
= 0; i
< row_info
->width
; i
++)
3981 v
= (png_byte
)((*sp
>> sshift
) & 0x03);
3982 for (j
= 0; j
< jstop
; j
++)
3984 unsigned int tmp
= *dp
& (0x3f3f >> (6 - dshift
));
3985 tmp
|= (unsigned int)(v
<< dshift
);
3986 *dp
= (png_byte
)(tmp
& 0xff);
3988 if (dshift
== s_end
)
3995 dshift
= (unsigned int)((int)dshift
+ s_inc
);
3998 if (sshift
== s_end
)
4005 sshift
= (unsigned int)((int)sshift
+ s_inc
);
4012 png_bytep sp
= row
+ (size_t)((row_info
->width
- 1) >> 1);
4013 png_bytep dp
= row
+ (size_t)((final_width
- 1) >> 1);
4014 unsigned int sshift
, dshift
;
4015 unsigned int s_start
, s_end
;
4018 int jstop
= (int)png_pass_inc
[pass
];
4020 #ifdef PNG_READ_PACKSWAP_SUPPORTED
4021 if ((transformations
& PNG_PACKSWAP
) != 0)
4023 sshift
= (((row_info
->width
+ 1) & 0x01) << 2);
4024 dshift
= (((final_width
+ 1) & 0x01) << 2);
4033 sshift
= ((1 - ((row_info
->width
+ 1) & 0x01)) << 2);
4034 dshift
= ((1 - ((final_width
+ 1) & 0x01)) << 2);
4040 for (i
= 0; i
< row_info
->width
; i
++)
4042 png_byte v
= (png_byte
)((*sp
>> sshift
) & 0x0f);
4045 for (j
= 0; j
< jstop
; j
++)
4047 unsigned int tmp
= *dp
& (0xf0f >> (4 - dshift
));
4048 tmp
|= (unsigned int)(v
<< dshift
);
4049 *dp
= (png_byte
)(tmp
& 0xff);
4051 if (dshift
== s_end
)
4058 dshift
= (unsigned int)((int)dshift
+ s_inc
);
4061 if (sshift
== s_end
)
4068 sshift
= (unsigned int)((int)sshift
+ s_inc
);
4075 size_t pixel_bytes
= (row_info
->pixel_depth
>> 3);
4077 png_bytep sp
= row
+ (size_t)(row_info
->width
- 1)
4080 png_bytep dp
= row
+ (size_t)(final_width
- 1) * pixel_bytes
;
4082 int jstop
= (int)png_pass_inc
[pass
];
4085 for (i
= 0; i
< row_info
->width
; i
++)
4087 png_byte v
[8]; /* SAFE; pixel_depth does not exceed 64 */
4090 memcpy(v
, sp
, pixel_bytes
);
4092 for (j
= 0; j
< jstop
; j
++)
4094 memcpy(dp
, v
, pixel_bytes
);
4104 row_info
->width
= final_width
;
4105 row_info
->rowbytes
= PNG_ROWBYTES(row_info
->pixel_depth
, final_width
);
4107 #ifndef PNG_READ_PACKSWAP_SUPPORTED
4108 PNG_UNUSED(transformations
) /* Silence compiler warning */
4111 #endif /* READ_INTERLACING */
4114 png_read_filter_row_sub(png_row_infop row_info
, png_bytep row
,
4115 png_const_bytep prev_row
)
4118 size_t istop
= row_info
->rowbytes
;
4119 unsigned int bpp
= (row_info
->pixel_depth
+ 7) >> 3;
4120 png_bytep rp
= row
+ bpp
;
4122 PNG_UNUSED(prev_row
)
4124 for (i
= bpp
; i
< istop
; i
++)
4126 *rp
= (png_byte
)(((int)(*rp
) + (int)(*(rp
-bpp
))) & 0xff);
4132 png_read_filter_row_up(png_row_infop row_info
, png_bytep row
,
4133 png_const_bytep prev_row
)
4136 size_t istop
= row_info
->rowbytes
;
4138 png_const_bytep pp
= prev_row
;
4140 for (i
= 0; i
< istop
; i
++)
4142 *rp
= (png_byte
)(((int)(*rp
) + (int)(*pp
++)) & 0xff);
4148 png_read_filter_row_avg(png_row_infop row_info
, png_bytep row
,
4149 png_const_bytep prev_row
)
4153 png_const_bytep pp
= prev_row
;
4154 unsigned int bpp
= (row_info
->pixel_depth
+ 7) >> 3;
4155 size_t istop
= row_info
->rowbytes
- bpp
;
4157 for (i
= 0; i
< bpp
; i
++)
4159 *rp
= (png_byte
)(((int)(*rp
) +
4160 ((int)(*pp
++) / 2 )) & 0xff);
4165 for (i
= 0; i
< istop
; i
++)
4167 *rp
= (png_byte
)(((int)(*rp
) +
4168 (int)(*pp
++ + *(rp
-bpp
)) / 2 ) & 0xff);
4175 png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info
, png_bytep row
,
4176 png_const_bytep prev_row
)
4178 png_bytep rp_end
= row
+ row_info
->rowbytes
;
4181 /* First pixel/byte */
4184 *row
++ = (png_byte
)a
;
4187 while (row
< rp_end
)
4189 int b
, pa
, pb
, pc
, p
;
4191 a
&= 0xff; /* From previous iteration or start */
4202 pa
= p
< 0 ? -p
: p
;
4203 pb
= pc
< 0 ? -pc
: pc
;
4204 pc
= (p
+ pc
) < 0 ? -(p
+ pc
) : p
+ pc
;
4207 /* Find the best predictor, the least of pa, pb, pc favoring the earlier
4208 * ones in the case of a tie.
4216 /* Calculate the current pixel in a, and move the previous row pixel to c
4217 * for the next time round the loop
4221 *row
++ = (png_byte
)a
;
4226 png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info
, png_bytep row
,
4227 png_const_bytep prev_row
)
4229 unsigned int bpp
= (row_info
->pixel_depth
+ 7) >> 3;
4230 png_bytep rp_end
= row
+ bpp
;
4232 /* Process the first pixel in the row completely (this is the same as 'up'
4233 * because there is only one candidate predictor for the first row).
4235 while (row
< rp_end
)
4237 int a
= *row
+ *prev_row
++;
4238 *row
++ = (png_byte
)a
;
4242 rp_end
= rp_end
+ (row_info
->rowbytes
- bpp
);
4244 while (row
< rp_end
)
4246 int a
, b
, c
, pa
, pb
, pc
, p
;
4248 c
= *(prev_row
- bpp
);
4260 pa
= p
< 0 ? -p
: p
;
4261 pb
= pc
< 0 ? -pc
: pc
;
4262 pc
= (p
+ pc
) < 0 ? -(p
+ pc
) : p
+ pc
;
4272 *row
++ = (png_byte
)a
;
4277 png_init_filter_functions(png_structrp pp
)
4278 /* This function is called once for every PNG image (except for PNG images
4279 * that only use PNG_FILTER_VALUE_NONE for all rows) to set the
4280 * implementations required to reverse the filtering of PNG rows. Reversing
4281 * the filter is the first transformation performed on the row data. It is
4282 * performed in place, therefore an implementation can be selected based on
4283 * the image pixel format. If the implementation depends on image width then
4284 * take care to ensure that it works correctly if the image is interlaced -
4285 * interlacing causes the actual row width to vary.
4288 unsigned int bpp
= (pp
->pixel_depth
+ 7) >> 3;
4290 pp
->read_filter
[PNG_FILTER_VALUE_SUB
-1] = png_read_filter_row_sub
;
4291 pp
->read_filter
[PNG_FILTER_VALUE_UP
-1] = png_read_filter_row_up
;
4292 pp
->read_filter
[PNG_FILTER_VALUE_AVG
-1] = png_read_filter_row_avg
;
4294 pp
->read_filter
[PNG_FILTER_VALUE_PAETH
-1] =
4295 png_read_filter_row_paeth_1byte_pixel
;
4297 pp
->read_filter
[PNG_FILTER_VALUE_PAETH
-1] =
4298 png_read_filter_row_paeth_multibyte_pixel
;
4300 #ifdef PNG_FILTER_OPTIMIZATIONS
4301 /* To use this define PNG_FILTER_OPTIMIZATIONS as the name of a function to
4302 * call to install hardware optimizations for the above functions; simply
4303 * replace whatever elements of the pp->read_filter[] array with a hardware
4304 * specific (or, for that matter, generic) optimization.
4306 * To see an example of this examine what configure.ac does when
4307 * --enable-arm-neon is specified on the command line.
4309 PNG_FILTER_OPTIMIZATIONS(pp
, bpp
);
4314 png_read_filter_row(png_structrp pp
, png_row_infop row_info
, png_bytep row
,
4315 png_const_bytep prev_row
, int filter
)
4317 /* OPTIMIZATION: DO NOT MODIFY THIS FUNCTION, instead #define
4318 * PNG_FILTER_OPTIMIZATIONS to a function that overrides the generic
4319 * implementations. See png_init_filter_functions above.
4321 if (filter
> PNG_FILTER_VALUE_NONE
&& filter
< PNG_FILTER_VALUE_LAST
)
4323 if (pp
->read_filter
[0] == NULL
)
4324 png_init_filter_functions(pp
);
4326 pp
->read_filter
[filter
-1](row_info
, row
, prev_row
);
4330 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
4332 png_read_IDAT_data(png_structrp png_ptr
, png_bytep output
,
4333 png_alloc_size_t avail_out
)
4335 /* Loop reading IDATs and decompressing the result into output[avail_out] */
4336 png_ptr
->zstream
.next_out
= output
;
4337 png_ptr
->zstream
.avail_out
= 0; /* safety: set below */
4345 png_byte tmpbuf
[PNG_INFLATE_BUF_SIZE
];
4347 if (png_ptr
->zstream
.avail_in
== 0)
4352 #ifdef PNG_READ_APNG_SUPPORTED
4353 png_uint_32 bytes_to_skip
= 0;
4355 while (png_ptr
->idat_size
== 0 || bytes_to_skip
!= 0)
4357 png_crc_finish(png_ptr
, bytes_to_skip
);
4360 png_ptr
->idat_size
= png_read_chunk_header(png_ptr
);
4361 if (png_ptr
->num_frames_read
== 0)
4363 if (png_ptr
->chunk_name
!= png_IDAT
)
4364 png_error(png_ptr
, "Not enough image data");
4368 if (png_ptr
->chunk_name
== png_IEND
)
4369 png_error(png_ptr
, "Not enough image data");
4370 if (png_ptr
->chunk_name
!= png_fdAT
)
4372 png_warning(png_ptr
, "Skipped (ignored) a chunk "
4373 "between APNG chunks");
4374 bytes_to_skip
= png_ptr
->idat_size
;
4378 png_ensure_sequence_number(png_ptr
, png_ptr
->idat_size
);
4380 png_ptr
->idat_size
-= 4;
4384 while (png_ptr
->idat_size
== 0)
4386 png_crc_finish(png_ptr
, 0);
4388 png_ptr
->idat_size
= png_read_chunk_header(png_ptr
);
4389 /* This is an error even in the 'check' case because the code just
4390 * consumed a non-IDAT header.
4392 if (png_ptr
->chunk_name
!= png_IDAT
)
4393 png_error(png_ptr
, "Not enough image data");
4395 #endif /* READ_APNG */
4397 avail_in
= png_ptr
->IDAT_read_size
;
4399 if (avail_in
> png_ptr
->idat_size
)
4400 avail_in
= (uInt
)png_ptr
->idat_size
;
4402 /* A PNG with a gradually increasing IDAT size will defeat this attempt
4403 * to minimize memory usage by causing lots of re-allocs, but
4404 * realistically doing IDAT_read_size re-allocs is not likely to be a
4407 buffer
= png_read_buffer(png_ptr
, avail_in
, 0/*error*/);
4409 png_crc_read(png_ptr
, buffer
, avail_in
);
4410 png_ptr
->idat_size
-= avail_in
;
4412 png_ptr
->zstream
.next_in
= buffer
;
4413 png_ptr
->zstream
.avail_in
= avail_in
;
4416 /* And set up the output side. */
4417 if (output
!= NULL
) /* standard read */
4419 uInt out
= ZLIB_IO_MAX
;
4421 if (out
> avail_out
)
4422 out
= (uInt
)avail_out
;
4425 png_ptr
->zstream
.avail_out
= out
;
4428 else /* after last row, checking for end */
4430 png_ptr
->zstream
.next_out
= tmpbuf
;
4431 png_ptr
->zstream
.avail_out
= (sizeof tmpbuf
);
4434 /* Use NO_FLUSH; this gives zlib the maximum opportunity to optimize the
4435 * process. If the LZ stream is truncated the sequential reader will
4436 * terminally damage the stream, above, by reading the chunk header of the
4437 * following chunk (it then exits with png_error).
4439 * TODO: deal more elegantly with truncated IDAT lists.
4441 ret
= PNG_INFLATE(png_ptr
, Z_NO_FLUSH
);
4443 /* Take the unconsumed output back. */
4445 avail_out
+= png_ptr
->zstream
.avail_out
;
4447 else /* avail_out counts the extra bytes */
4448 avail_out
+= (sizeof tmpbuf
) - png_ptr
->zstream
.avail_out
;
4450 png_ptr
->zstream
.avail_out
= 0;
4452 if (ret
== Z_STREAM_END
)
4454 /* Do this for safety; we won't read any more into this row. */
4455 png_ptr
->zstream
.next_out
= NULL
;
4457 png_ptr
->mode
|= PNG_AFTER_IDAT
;
4458 png_ptr
->flags
|= PNG_FLAG_ZSTREAM_ENDED
;
4459 #ifdef PNG_READ_APNG_SUPPORTED
4460 png_ptr
->num_frames_read
++;
4463 if (png_ptr
->zstream
.avail_in
> 0 || png_ptr
->idat_size
> 0)
4464 png_chunk_benign_error(png_ptr
, "Extra compressed data");
4470 png_zstream_error(png_ptr
, ret
);
4473 png_chunk_error(png_ptr
, png_ptr
->zstream
.msg
);
4477 png_chunk_benign_error(png_ptr
, png_ptr
->zstream
.msg
);
4481 } while (avail_out
> 0);
4485 /* The stream ended before the image; this is the same as too few IDATs so
4486 * should be handled the same way.
4489 png_error(png_ptr
, "Not enough image data");
4491 else /* the deflate stream contained extra data */
4492 png_chunk_benign_error(png_ptr
, "Too much image data");
4497 png_read_finish_IDAT(png_structrp png_ptr
)
4499 /* We don't need any more data and the stream should have ended, however the
4500 * LZ end code may actually not have been processed. In this case we must
4501 * read it otherwise stray unread IDAT data or, more likely, an IDAT chunk
4502 * may still remain to be consumed.
4504 if ((png_ptr
->flags
& PNG_FLAG_ZSTREAM_ENDED
) == 0)
4506 /* The NULL causes png_read_IDAT_data to swallow any remaining bytes in
4507 * the compressed stream, but the stream may be damaged too, so even after
4508 * this call we may need to terminate the zstream ownership.
4510 png_read_IDAT_data(png_ptr
, NULL
, 0);
4511 png_ptr
->zstream
.next_out
= NULL
; /* safety */
4513 /* Now clear everything out for safety; the following may not have been
4516 if ((png_ptr
->flags
& PNG_FLAG_ZSTREAM_ENDED
) == 0)
4518 png_ptr
->mode
|= PNG_AFTER_IDAT
;
4519 png_ptr
->flags
|= PNG_FLAG_ZSTREAM_ENDED
;
4523 /* If the zstream has not been released do it now *and* terminate the reading
4524 * of the final IDAT chunk.
4526 if (png_ptr
->zowner
== png_IDAT
)
4528 /* Always do this; the pointers otherwise point into the read buffer. */
4529 png_ptr
->zstream
.next_in
= NULL
;
4530 png_ptr
->zstream
.avail_in
= 0;
4532 /* Now we no longer own the zstream. */
4533 png_ptr
->zowner
= 0;
4535 /* The slightly weird semantics of the sequential IDAT reading is that we
4536 * are always in or at the end of an IDAT chunk, so we always need to do a
4537 * crc_finish here. If idat_size is non-zero we also need to read the
4538 * spurious bytes at the end of the chunk now.
4540 (void)png_crc_finish(png_ptr
, png_ptr
->idat_size
);
4545 png_read_finish_row(png_structrp png_ptr
)
4547 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
4549 /* Start of interlace block */
4550 static const png_byte png_pass_start
[7] = {0, 4, 0, 2, 0, 1, 0};
4552 /* Offset to next interlace block */
4553 static const png_byte png_pass_inc
[7] = {8, 8, 4, 4, 2, 2, 1};
4555 /* Start of interlace block in the y direction */
4556 static const png_byte png_pass_ystart
[7] = {0, 0, 4, 0, 2, 0, 1};
4558 /* Offset to next interlace block in the y direction */
4559 static const png_byte png_pass_yinc
[7] = {8, 8, 8, 4, 4, 2, 2};
4561 png_debug(1, "in png_read_finish_row");
4562 png_ptr
->row_number
++;
4563 if (png_ptr
->row_number
< png_ptr
->num_rows
)
4566 if (png_ptr
->interlaced
!= 0)
4568 png_ptr
->row_number
= 0;
4570 /* TO DO: don't do this if prev_row isn't needed (requires
4571 * read-ahead of the next row's filter byte.
4573 memset(png_ptr
->prev_row
, 0, png_ptr
->rowbytes
+ 1);
4579 if (png_ptr
->pass
>= 7)
4582 png_ptr
->iwidth
= (png_ptr
->width
+
4583 png_pass_inc
[png_ptr
->pass
] - 1 -
4584 png_pass_start
[png_ptr
->pass
]) /
4585 png_pass_inc
[png_ptr
->pass
];
4587 if ((png_ptr
->transformations
& PNG_INTERLACE
) == 0)
4589 png_ptr
->num_rows
= (png_ptr
->height
+
4590 png_pass_yinc
[png_ptr
->pass
] - 1 -
4591 png_pass_ystart
[png_ptr
->pass
]) /
4592 png_pass_yinc
[png_ptr
->pass
];
4595 else /* if (png_ptr->transformations & PNG_INTERLACE) */
4596 break; /* libpng deinterlacing sees every row */
4598 } while (png_ptr
->num_rows
== 0 || png_ptr
->iwidth
== 0);
4600 if (png_ptr
->pass
< 7)
4604 /* Here after at the end of the last row of the last pass. */
4605 png_read_finish_IDAT(png_ptr
);
4607 #endif /* SEQUENTIAL_READ */
4610 png_read_start_row(png_structrp png_ptr
)
4612 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
4614 /* Start of interlace block */
4615 static const png_byte png_pass_start
[7] = {0, 4, 0, 2, 0, 1, 0};
4617 /* Offset to next interlace block */
4618 static const png_byte png_pass_inc
[7] = {8, 8, 4, 4, 2, 2, 1};
4620 /* Start of interlace block in the y direction */
4621 static const png_byte png_pass_ystart
[7] = {0, 0, 4, 0, 2, 0, 1};
4623 /* Offset to next interlace block in the y direction */
4624 static const png_byte png_pass_yinc
[7] = {8, 8, 8, 4, 4, 2, 2};
4626 unsigned int max_pixel_depth
;
4629 png_debug(1, "in png_read_start_row");
4631 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
4632 png_init_read_transformations(png_ptr
);
4634 if (png_ptr
->interlaced
!= 0)
4636 if ((png_ptr
->transformations
& PNG_INTERLACE
) == 0)
4637 png_ptr
->num_rows
= (png_ptr
->height
+ png_pass_yinc
[0] - 1 -
4638 png_pass_ystart
[0]) / png_pass_yinc
[0];
4641 png_ptr
->num_rows
= png_ptr
->height
;
4643 png_ptr
->iwidth
= (png_ptr
->width
+
4644 png_pass_inc
[png_ptr
->pass
] - 1 -
4645 png_pass_start
[png_ptr
->pass
]) /
4646 png_pass_inc
[png_ptr
->pass
];
4651 png_ptr
->num_rows
= png_ptr
->height
;
4652 png_ptr
->iwidth
= png_ptr
->width
;
4655 max_pixel_depth
= (unsigned int)png_ptr
->pixel_depth
;
4657 /* WARNING: * png_read_transform_info (pngrtran.c) performs a simpler set of
4658 * calculations to calculate the final pixel depth, then
4659 * png_do_read_transforms actually does the transforms. This means that the
4660 * code which effectively calculates this value is actually repeated in three
4661 * separate places. They must all match. Innocent changes to the order of
4662 * transformations can and will break libpng in a way that causes memory
4667 #ifdef PNG_READ_PACK_SUPPORTED
4668 if ((png_ptr
->transformations
& PNG_PACK
) != 0 && png_ptr
->bit_depth
< 8)
4669 max_pixel_depth
= 8;
4672 #ifdef PNG_READ_EXPAND_SUPPORTED
4673 if ((png_ptr
->transformations
& PNG_EXPAND
) != 0)
4675 if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
4677 if (png_ptr
->num_trans
!= 0)
4678 max_pixel_depth
= 32;
4681 max_pixel_depth
= 24;
4684 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_GRAY
)
4686 if (max_pixel_depth
< 8)
4687 max_pixel_depth
= 8;
4689 if (png_ptr
->num_trans
!= 0)
4690 max_pixel_depth
*= 2;
4693 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_RGB
)
4695 if (png_ptr
->num_trans
!= 0)
4697 max_pixel_depth
*= 4;
4698 max_pixel_depth
/= 3;
4704 #ifdef PNG_READ_EXPAND_16_SUPPORTED
4705 if ((png_ptr
->transformations
& PNG_EXPAND_16
) != 0)
4707 # ifdef PNG_READ_EXPAND_SUPPORTED
4708 /* In fact it is an error if it isn't supported, but checking is
4711 if ((png_ptr
->transformations
& PNG_EXPAND
) != 0)
4713 if (png_ptr
->bit_depth
< 16)
4714 max_pixel_depth
*= 2;
4718 png_ptr
->transformations
&= ~PNG_EXPAND_16
;
4722 #ifdef PNG_READ_FILLER_SUPPORTED
4723 if ((png_ptr
->transformations
& (PNG_FILLER
)) != 0)
4725 if (png_ptr
->color_type
== PNG_COLOR_TYPE_GRAY
)
4727 if (max_pixel_depth
<= 8)
4728 max_pixel_depth
= 16;
4731 max_pixel_depth
= 32;
4734 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_RGB
||
4735 png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
4737 if (max_pixel_depth
<= 32)
4738 max_pixel_depth
= 32;
4741 max_pixel_depth
= 64;
4746 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
4747 if ((png_ptr
->transformations
& PNG_GRAY_TO_RGB
) != 0)
4750 #ifdef PNG_READ_EXPAND_SUPPORTED
4751 (png_ptr
->num_trans
!= 0 &&
4752 (png_ptr
->transformations
& PNG_EXPAND
) != 0) ||
4754 #ifdef PNG_READ_FILLER_SUPPORTED
4755 (png_ptr
->transformations
& (PNG_FILLER
)) != 0 ||
4757 png_ptr
->color_type
== PNG_COLOR_TYPE_GRAY_ALPHA
)
4759 if (max_pixel_depth
<= 16)
4760 max_pixel_depth
= 32;
4763 max_pixel_depth
= 64;
4768 if (max_pixel_depth
<= 8)
4770 if (png_ptr
->color_type
== PNG_COLOR_TYPE_RGB_ALPHA
)
4771 max_pixel_depth
= 32;
4774 max_pixel_depth
= 24;
4777 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_RGB_ALPHA
)
4778 max_pixel_depth
= 64;
4781 max_pixel_depth
= 48;
4786 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) && \
4787 defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
4788 if ((png_ptr
->transformations
& PNG_USER_TRANSFORM
) != 0)
4790 unsigned int user_pixel_depth
= png_ptr
->user_transform_depth
*
4791 png_ptr
->user_transform_channels
;
4793 if (user_pixel_depth
> max_pixel_depth
)
4794 max_pixel_depth
= user_pixel_depth
;
4798 /* This value is stored in png_struct and double checked in the row read
4801 png_ptr
->maximum_pixel_depth
= (png_byte
)max_pixel_depth
;
4802 png_ptr
->transformed_pixel_depth
= 0; /* calculated on demand */
4804 /* Align the width on the next larger 8 pixels. Mainly used
4807 row_bytes
= ((png_ptr
->width
+ 7) & ~((png_uint_32
)7));
4808 /* Calculate the maximum bytes needed, adding a byte and a pixel
4811 row_bytes
= PNG_ROWBYTES(max_pixel_depth
, row_bytes
) +
4812 1 + ((max_pixel_depth
+ 7) >> 3U);
4814 #ifdef PNG_MAX_MALLOC_64K
4815 if (row_bytes
> (png_uint_32
)65536L)
4816 png_error(png_ptr
, "This image requires a row greater than 64KB");
4819 if (row_bytes
+ 48 > png_ptr
->old_big_row_buf_size
)
4821 png_free(png_ptr
, png_ptr
->big_row_buf
);
4822 png_free(png_ptr
, png_ptr
->big_prev_row
);
4824 if (png_ptr
->interlaced
!= 0)
4825 png_ptr
->big_row_buf
= (png_bytep
)png_calloc(png_ptr
,
4829 png_ptr
->big_row_buf
= (png_bytep
)png_malloc(png_ptr
, row_bytes
+ 48);
4831 png_ptr
->big_prev_row
= (png_bytep
)png_malloc(png_ptr
, row_bytes
+ 48);
4833 #ifdef PNG_ALIGNED_MEMORY_SUPPORTED
4834 /* Use 16-byte aligned memory for row_buf with at least 16 bytes
4835 * of padding before and after row_buf; treat prev_row similarly.
4836 * NOTE: the alignment is to the start of the pixels, one beyond the start
4837 * of the buffer, because of the filter byte. Prior to libpng 1.5.6 this
4838 * was incorrect; the filter byte was aligned, which had the exact
4839 * opposite effect of that intended.
4842 png_bytep temp
= png_ptr
->big_row_buf
+ 32;
4843 size_t extra
= (size_t)temp
& 0x0f;
4844 png_ptr
->row_buf
= temp
- extra
- 1/*filter byte*/;
4846 temp
= png_ptr
->big_prev_row
+ 32;
4847 extra
= (size_t)temp
& 0x0f;
4848 png_ptr
->prev_row
= temp
- extra
- 1/*filter byte*/;
4851 /* Use 31 bytes of padding before and 17 bytes after row_buf. */
4852 png_ptr
->row_buf
= png_ptr
->big_row_buf
+ 31;
4853 png_ptr
->prev_row
= png_ptr
->big_prev_row
+ 31;
4855 png_ptr
->old_big_row_buf_size
= row_bytes
+ 48;
4858 #ifdef PNG_MAX_MALLOC_64K
4859 if (png_ptr
->rowbytes
> 65535)
4860 png_error(png_ptr
, "This image requires a row greater than 64KB");
4863 if (png_ptr
->rowbytes
> (PNG_SIZE_MAX
- 1))
4864 png_error(png_ptr
, "Row has too many bytes to allocate in memory");
4866 memset(png_ptr
->prev_row
, 0, png_ptr
->rowbytes
+ 1);
4868 png_debug1(3, "width = %u,", png_ptr
->width
);
4869 png_debug1(3, "height = %u,", png_ptr
->height
);
4870 png_debug1(3, "iwidth = %u,", png_ptr
->iwidth
);
4871 png_debug1(3, "num_rows = %u,", png_ptr
->num_rows
);
4872 png_debug1(3, "rowbytes = %lu,", (unsigned long)png_ptr
->rowbytes
);
4873 png_debug1(3, "irowbytes = %lu",
4874 (unsigned long)PNG_ROWBYTES(png_ptr
->pixel_depth
, png_ptr
->iwidth
) + 1);
4876 /* The sequential reader needs a buffer for IDAT, but the progressive reader
4877 * does not, so free the read buffer now regardless; the sequential reader
4878 * reallocates it on demand.
4880 if (png_ptr
->read_buffer
!= NULL
)
4882 png_bytep buffer
= png_ptr
->read_buffer
;
4884 png_ptr
->read_buffer_size
= 0;
4885 png_ptr
->read_buffer
= NULL
;
4886 png_free(png_ptr
, buffer
);
4889 /* Finally claim the zstream for the inflate of the IDAT data, use the bits
4890 * value from the stream (note that this will result in a fatal error if the
4891 * IDAT stream has a bogus deflate header window_bits value, but this should
4892 * not be happening any longer!)
4894 if (png_inflate_claim(png_ptr
, png_IDAT
) != Z_OK
)
4895 png_error(png_ptr
, png_ptr
->zstream
.msg
);
4897 png_ptr
->flags
|= PNG_FLAG_ROW_INIT
;
4900 #ifdef PNG_READ_APNG_SUPPORTED
4901 /* This function is to be called after the main IDAT set has been read and
4902 * before a new IDAT is read. It resets some parts of png_ptr
4903 * to make them usable by the read functions again */
4905 png_read_reset(png_structp png_ptr
)
4907 png_ptr
->mode
&= ~PNG_HAVE_IDAT
;
4908 png_ptr
->mode
&= ~PNG_AFTER_IDAT
;
4909 png_ptr
->row_number
= 0;
4914 png_read_reinit(png_structp png_ptr
, png_infop info_ptr
)
4916 png_ptr
->width
= info_ptr
->next_frame_width
;
4917 png_ptr
->height
= info_ptr
->next_frame_height
;
4918 png_ptr
->rowbytes
= PNG_ROWBYTES(png_ptr
->pixel_depth
,png_ptr
->width
);
4919 png_ptr
->info_rowbytes
= PNG_ROWBYTES(info_ptr
->pixel_depth
,
4921 if (png_ptr
->prev_row
!= NULL
)
4922 memset(png_ptr
->prev_row
, 0, png_ptr
->rowbytes
+ 1);
4925 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
4926 /* same as png_read_reset() but for the progressive reader */
4928 png_progressive_read_reset(png_structp png_ptr
)
4930 #ifdef PNG_READ_INTERLACING_SUPPORTED
4931 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
4933 /* Start of interlace block */
4934 static PNG_CONST png_byte png_pass_start
[] = {0, 4, 0, 2, 0, 1, 0};
4936 /* Offset to next interlace block */
4937 static PNG_CONST png_byte png_pass_inc
[] = {8, 8, 4, 4, 2, 2, 1};
4939 /* Start of interlace block in the y direction */
4940 static PNG_CONST png_byte png_pass_ystart
[] = {0, 0, 4, 0, 2, 0, 1};
4942 /* Offset to next interlace block in the y direction */
4943 static PNG_CONST png_byte png_pass_yinc
[] = {8, 8, 8, 4, 4, 2, 2};
4945 if (png_ptr
->interlaced
!= 0)
4947 if ((png_ptr
->transformations
& PNG_INTERLACE
) == 0)
4948 png_ptr
->num_rows
= (png_ptr
->height
+ png_pass_yinc
[0] - 1 -
4949 png_pass_ystart
[0]) / png_pass_yinc
[0];
4951 png_ptr
->num_rows
= png_ptr
->height
;
4953 png_ptr
->iwidth
= (png_ptr
->width
+
4954 png_pass_inc
[png_ptr
->pass
] - 1 -
4955 png_pass_start
[png_ptr
->pass
]) /
4956 png_pass_inc
[png_ptr
->pass
];
4959 #endif /* READ_INTERLACING */
4961 png_ptr
->num_rows
= png_ptr
->height
;
4962 png_ptr
->iwidth
= png_ptr
->width
;
4964 png_ptr
->flags
&= ~PNG_FLAG_ZSTREAM_ENDED
;
4965 if (inflateReset(&(png_ptr
->zstream
)) != Z_OK
)
4966 png_error(png_ptr
, "inflateReset failed");
4967 png_ptr
->zstream
.avail_in
= 0;
4968 png_ptr
->zstream
.next_in
= 0;
4969 png_ptr
->zstream
.next_out
= png_ptr
->row_buf
;
4970 png_ptr
->zstream
.avail_out
= (uInt
)PNG_ROWBYTES(png_ptr
->pixel_depth
,
4971 png_ptr
->iwidth
) + 1;
4973 #endif /* PROGRESSIVE_READ */
4974 #endif /* READ_APNG */