2 /* pngrutil.c - utilities to read a PNG file
4 * Copyright (c) 2018-2022 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))
144 png_error(png_ptr
, "Not a PNG file");
146 png_error(png_ptr
, "PNG file corrupted by ASCII conversion");
149 png_ptr
->mode
|= PNG_HAVE_PNG_SIGNATURE
;
152 /* Read the chunk header (length + type name).
153 * Put the type name into png_ptr->chunk_name, and return the length.
155 png_uint_32
/* PRIVATE */
156 png_read_chunk_header(png_structrp png_ptr
)
161 #ifdef PNG_IO_STATE_SUPPORTED
162 png_ptr
->io_state
= PNG_IO_READING
| PNG_IO_CHUNK_HDR
;
165 /* Read the length and the chunk name.
166 * This must be performed in a single I/O call.
168 png_read_data(png_ptr
, buf
, 8);
169 length
= png_get_uint_31(png_ptr
, buf
);
171 /* Put the chunk name into png_ptr->chunk_name. */
172 png_ptr
->chunk_name
= PNG_CHUNK_FROM_STRING(buf
+4);
174 png_debug2(0, "Reading %lx chunk, length = %lu",
175 (unsigned long)png_ptr
->chunk_name
, (unsigned long)length
);
177 /* Reset the crc and run it over the chunk name. */
178 png_reset_crc(png_ptr
);
179 png_calculate_crc(png_ptr
, buf
+ 4, 4);
181 /* Check to see if chunk name is valid. */
182 png_check_chunk_name(png_ptr
, png_ptr
->chunk_name
);
184 /* 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 ((int)(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 #if ZLIB_VERNUM >= 0x1290 && \
425 defined(PNG_SET_OPTION_SUPPORTED) && defined(PNG_IGNORE_ADLER32)
426 if (((png_ptr
->options
>> PNG_IGNORE_ADLER32
) & 3) == PNG_OPTION_ON
)
427 /* Turn off validation of the ADLER32 checksum in IDAT chunks */
428 ret
= inflateValidate(&png_ptr
->zstream
, 0);
432 png_ptr
->zowner
= owner
;
435 png_zstream_error(png_ptr
, ret
);
445 #if ZLIB_VERNUM >= 0x1240
446 /* Handle the start of the inflate stream if we called inflateInit2(strm,0);
447 * in this case some zlib versions skip validation of the CINFO field and, in
448 * certain circumstances, libpng may end up displaying an invalid image, in
449 * contrast to implementations that call zlib in the normal way (e.g. libpng
453 png_zlib_inflate(png_structrp png_ptr
, int flush
)
455 if (png_ptr
->zstream_start
&& png_ptr
->zstream
.avail_in
> 0)
457 if ((*png_ptr
->zstream
.next_in
>> 4) > 7)
459 png_ptr
->zstream
.msg
= "invalid window size (libpng)";
463 png_ptr
->zstream_start
= 0;
466 return inflate(&png_ptr
->zstream
, flush
);
468 #endif /* Zlib >= 1.2.4 */
470 #ifdef PNG_READ_COMPRESSED_TEXT_SUPPORTED
471 #if defined(PNG_READ_zTXt_SUPPORTED) || defined (PNG_READ_iTXt_SUPPORTED)
472 /* png_inflate now returns zlib error codes including Z_OK and Z_STREAM_END to
473 * allow the caller to do multiple calls if required. If the 'finish' flag is
474 * set Z_FINISH will be passed to the final inflate() call and Z_STREAM_END must
475 * be returned or there has been a problem, otherwise Z_SYNC_FLUSH is used and
476 * Z_OK or Z_STREAM_END will be returned on success.
478 * The input and output sizes are updated to the actual amounts of data consumed
479 * or written, not the amount available (as in a z_stream). The data pointers
480 * are not changed, so the next input is (data+input_size) and the next
481 * available output is (output+output_size).
484 png_inflate(png_structrp png_ptr
, png_uint_32 owner
, int finish
,
485 /* INPUT: */ png_const_bytep input
, png_uint_32p input_size_ptr
,
486 /* OUTPUT: */ png_bytep output
, png_alloc_size_t
*output_size_ptr
)
488 if (png_ptr
->zowner
== owner
) /* Else not claimed */
491 png_alloc_size_t avail_out
= *output_size_ptr
;
492 png_uint_32 avail_in
= *input_size_ptr
;
494 /* zlib can't necessarily handle more than 65535 bytes at once (i.e. it
495 * can't even necessarily handle 65536 bytes) because the type uInt is
496 * "16 bits or more". Consequently it is necessary to chunk the input to
497 * zlib. This code uses ZLIB_IO_MAX, from pngpriv.h, as the maximum (the
498 * maximum value that can be stored in a uInt.) It is possible to set
499 * ZLIB_IO_MAX to a lower value in pngpriv.h and this may sometimes have
500 * a performance advantage, because it reduces the amount of data accessed
501 * at each step and that may give the OS more time to page it in.
503 png_ptr
->zstream
.next_in
= PNGZ_INPUT_CAST(input
);
504 /* avail_in and avail_out are set below from 'size' */
505 png_ptr
->zstream
.avail_in
= 0;
506 png_ptr
->zstream
.avail_out
= 0;
508 /* Read directly into the output if it is available (this is set to
509 * a local buffer below if output is NULL).
512 png_ptr
->zstream
.next_out
= output
;
517 Byte local_buffer
[PNG_INFLATE_BUF_SIZE
];
519 /* zlib INPUT BUFFER */
520 /* The setting of 'avail_in' used to be outside the loop; by setting it
521 * inside it is possible to chunk the input to zlib and simply rely on
522 * zlib to advance the 'next_in' pointer. This allows arbitrary
523 * amounts of data to be passed through zlib at the unavoidable cost of
524 * requiring a window save (memcpy of up to 32768 output bytes)
525 * every ZLIB_IO_MAX input bytes.
527 avail_in
+= png_ptr
->zstream
.avail_in
; /* not consumed last time */
531 if (avail_in
< avail
)
532 avail
= (uInt
)avail_in
; /* safe: < than ZLIB_IO_MAX */
535 png_ptr
->zstream
.avail_in
= avail
;
537 /* zlib OUTPUT BUFFER */
538 avail_out
+= png_ptr
->zstream
.avail_out
; /* not written last time */
540 avail
= ZLIB_IO_MAX
; /* maximum zlib can process */
544 /* Reset the output buffer each time round if output is NULL and
545 * make available the full buffer, up to 'remaining_space'
547 png_ptr
->zstream
.next_out
= local_buffer
;
548 if ((sizeof local_buffer
) < avail
)
549 avail
= (sizeof local_buffer
);
552 if (avail_out
< avail
)
553 avail
= (uInt
)avail_out
; /* safe: < ZLIB_IO_MAX */
555 png_ptr
->zstream
.avail_out
= avail
;
558 /* zlib inflate call */
559 /* In fact 'avail_out' may be 0 at this point, that happens at the end
560 * of the read when the final LZ end code was not passed at the end of
561 * the previous chunk of input data. Tell zlib if we have reached the
562 * end of the output buffer.
564 ret
= PNG_INFLATE(png_ptr
, avail_out
> 0 ? Z_NO_FLUSH
:
565 (finish
? Z_FINISH
: Z_SYNC_FLUSH
));
566 } while (ret
== Z_OK
);
568 /* For safety kill the local buffer pointer now */
570 png_ptr
->zstream
.next_out
= NULL
;
572 /* Claw back the 'size' and 'remaining_space' byte counts. */
573 avail_in
+= png_ptr
->zstream
.avail_in
;
574 avail_out
+= png_ptr
->zstream
.avail_out
;
576 /* Update the input and output sizes; the updated values are the amount
577 * consumed or written, effectively the inverse of what zlib uses.
580 *output_size_ptr
-= avail_out
;
583 *input_size_ptr
-= avail_in
;
585 /* Ensure png_ptr->zstream.msg is set (even in the success case!) */
586 png_zstream_error(png_ptr
, ret
);
592 /* This is a bad internal error. The recovery assigns to the zstream msg
593 * pointer, which is not owned by the caller, but this is safe; it's only
596 png_ptr
->zstream
.msg
= PNGZ_MSG_CAST("zstream unclaimed");
597 return Z_STREAM_ERROR
;
602 * Decompress trailing data in a chunk. The assumption is that read_buffer
603 * points at an allocated area holding the contents of a chunk with a
604 * trailing compressed part. What we get back is an allocated area
605 * holding the original prefix part and an uncompressed version of the
606 * trailing part (the malloc area passed in is freed).
609 png_decompress_chunk(png_structrp png_ptr
,
610 png_uint_32 chunklength
, png_uint_32 prefix_size
,
611 png_alloc_size_t
*newlength
/* must be initialized to the maximum! */,
612 int terminate
/*add a '\0' to the end of the uncompressed data*/)
614 /* TODO: implement different limits for different types of chunk.
616 * The caller supplies *newlength set to the maximum length of the
617 * uncompressed data, but this routine allocates space for the prefix and
618 * maybe a '\0' terminator too. We have to assume that 'prefix_size' is
619 * limited only by the maximum chunk size.
621 png_alloc_size_t limit
= PNG_SIZE_MAX
;
623 # ifdef PNG_SET_USER_LIMITS_SUPPORTED
624 if (png_ptr
->user_chunk_malloc_max
> 0 &&
625 png_ptr
->user_chunk_malloc_max
< limit
)
626 limit
= png_ptr
->user_chunk_malloc_max
;
627 # elif PNG_USER_CHUNK_MALLOC_MAX > 0
628 if (PNG_USER_CHUNK_MALLOC_MAX
< limit
)
629 limit
= PNG_USER_CHUNK_MALLOC_MAX
;
632 if (limit
>= prefix_size
+ (terminate
!= 0))
636 limit
-= prefix_size
+ (terminate
!= 0);
638 if (limit
< *newlength
)
641 /* Now try to claim the stream. */
642 ret
= png_inflate_claim(png_ptr
, png_ptr
->chunk_name
);
646 png_uint_32 lzsize
= chunklength
- prefix_size
;
648 ret
= png_inflate(png_ptr
, png_ptr
->chunk_name
, 1/*finish*/,
649 /* input: */ png_ptr
->read_buffer
+ prefix_size
, &lzsize
,
650 /* output: */ NULL
, newlength
);
652 if (ret
== Z_STREAM_END
)
654 /* Use 'inflateReset' here, not 'inflateReset2' because this
655 * preserves the previously decided window size (otherwise it would
656 * be necessary to store the previous window size.) In practice
657 * this doesn't matter anyway, because png_inflate will call inflate
658 * with Z_FINISH in almost all cases, so the window will not be
661 if (inflateReset(&png_ptr
->zstream
) == Z_OK
)
663 /* Because of the limit checks above we know that the new,
664 * expanded, size will fit in a size_t (let alone an
665 * png_alloc_size_t). Use png_malloc_base here to avoid an
668 png_alloc_size_t new_size
= *newlength
;
669 png_alloc_size_t buffer_size
= prefix_size
+ new_size
+
671 png_bytep text
= png_voidcast(png_bytep
, png_malloc_base(png_ptr
,
676 memset(text
, 0, buffer_size
);
678 ret
= png_inflate(png_ptr
, png_ptr
->chunk_name
, 1/*finish*/,
679 png_ptr
->read_buffer
+ prefix_size
, &lzsize
,
680 text
+ prefix_size
, newlength
);
682 if (ret
== Z_STREAM_END
)
684 if (new_size
== *newlength
)
687 text
[prefix_size
+ *newlength
] = 0;
690 memcpy(text
, png_ptr
->read_buffer
, prefix_size
);
693 png_bytep old_ptr
= png_ptr
->read_buffer
;
695 png_ptr
->read_buffer
= text
;
696 png_ptr
->read_buffer_size
= buffer_size
;
697 text
= old_ptr
; /* freed below */
703 /* The size changed on the second read, there can be no
704 * guarantee that anything is correct at this point.
705 * The 'msg' pointer has been set to "unexpected end of
706 * LZ stream", which is fine, but return an error code
707 * that the caller won't accept.
709 ret
= PNG_UNEXPECTED_ZLIB_RETURN
;
713 else if (ret
== Z_OK
)
714 ret
= PNG_UNEXPECTED_ZLIB_RETURN
; /* for safety */
716 /* Free the text pointer (this is the old read_buffer on
719 png_free(png_ptr
, text
);
721 /* This really is very benign, but it's still an error because
722 * the extra space may otherwise be used as a Trojan Horse.
724 if (ret
== Z_STREAM_END
&&
725 chunklength
- prefix_size
!= lzsize
)
726 png_chunk_benign_error(png_ptr
, "extra compressed data");
731 /* Out of memory allocating the buffer */
733 png_zstream_error(png_ptr
, Z_MEM_ERROR
);
739 /* inflateReset failed, store the error message */
740 png_zstream_error(png_ptr
, ret
);
741 ret
= PNG_UNEXPECTED_ZLIB_RETURN
;
745 else if (ret
== Z_OK
)
746 ret
= PNG_UNEXPECTED_ZLIB_RETURN
;
748 /* Release the claimed stream */
752 else /* the claim failed */ if (ret
== Z_STREAM_END
) /* impossible! */
753 ret
= PNG_UNEXPECTED_ZLIB_RETURN
;
760 /* Application/configuration limits exceeded */
761 png_zstream_error(png_ptr
, Z_MEM_ERROR
);
765 #endif /* READ_zTXt || READ_iTXt */
766 #endif /* READ_COMPRESSED_TEXT */
768 #ifdef PNG_READ_iCCP_SUPPORTED
769 /* Perform a partial read and decompress, producing 'avail_out' bytes and
770 * reading from the current chunk as required.
773 png_inflate_read(png_structrp png_ptr
, png_bytep read_buffer
, uInt read_size
,
774 png_uint_32p chunk_bytes
, png_bytep next_out
, png_alloc_size_t
*out_size
,
777 if (png_ptr
->zowner
== png_ptr
->chunk_name
)
781 /* next_in and avail_in must have been initialized by the caller. */
782 png_ptr
->zstream
.next_out
= next_out
;
783 png_ptr
->zstream
.avail_out
= 0; /* set in the loop */
787 if (png_ptr
->zstream
.avail_in
== 0)
789 if (read_size
> *chunk_bytes
)
790 read_size
= (uInt
)*chunk_bytes
;
791 *chunk_bytes
-= read_size
;
794 png_crc_read(png_ptr
, read_buffer
, read_size
);
796 png_ptr
->zstream
.next_in
= read_buffer
;
797 png_ptr
->zstream
.avail_in
= read_size
;
800 if (png_ptr
->zstream
.avail_out
== 0)
802 uInt avail
= ZLIB_IO_MAX
;
803 if (avail
> *out_size
)
804 avail
= (uInt
)*out_size
;
807 png_ptr
->zstream
.avail_out
= avail
;
810 /* Use Z_SYNC_FLUSH when there is no more chunk data to ensure that all
811 * the available output is produced; this allows reading of truncated
814 ret
= PNG_INFLATE(png_ptr
, *chunk_bytes
> 0 ?
815 Z_NO_FLUSH
: (finish
? Z_FINISH
: Z_SYNC_FLUSH
));
817 while (ret
== Z_OK
&& (*out_size
> 0 || png_ptr
->zstream
.avail_out
> 0));
819 *out_size
+= png_ptr
->zstream
.avail_out
;
820 png_ptr
->zstream
.avail_out
= 0; /* Should not be required, but is safe */
822 /* Ensure the error message pointer is always set: */
823 png_zstream_error(png_ptr
, ret
);
829 png_ptr
->zstream
.msg
= PNGZ_MSG_CAST("zstream unclaimed");
830 return Z_STREAM_ERROR
;
833 #endif /* READ_iCCP */
835 /* Read and check the IDHR chunk */
838 png_handle_IHDR(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
841 png_uint_32 width
, height
;
842 int bit_depth
, color_type
, compression_type
, filter_type
;
845 png_debug(1, "in png_handle_IHDR");
847 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) != 0)
848 png_chunk_error(png_ptr
, "out of place");
850 /* Check the length */
852 png_chunk_error(png_ptr
, "invalid");
854 png_ptr
->mode
|= PNG_HAVE_IHDR
;
856 png_crc_read(png_ptr
, buf
, 13);
857 png_crc_finish(png_ptr
, 0);
859 width
= png_get_uint_31(png_ptr
, buf
);
860 height
= png_get_uint_31(png_ptr
, buf
+ 4);
863 compression_type
= buf
[10];
864 filter_type
= buf
[11];
865 interlace_type
= buf
[12];
867 /* Set internal variables */
868 png_ptr
->width
= width
;
869 png_ptr
->height
= height
;
870 png_ptr
->bit_depth
= (png_byte
)bit_depth
;
871 png_ptr
->interlaced
= (png_byte
)interlace_type
;
872 png_ptr
->color_type
= (png_byte
)color_type
;
873 #ifdef PNG_MNG_FEATURES_SUPPORTED
874 png_ptr
->filter_type
= (png_byte
)filter_type
;
876 png_ptr
->compression_type
= (png_byte
)compression_type
;
878 /* Find number of channels */
879 switch (png_ptr
->color_type
)
881 default: /* invalid, png_set_IHDR calls png_error */
882 case PNG_COLOR_TYPE_GRAY
:
883 case PNG_COLOR_TYPE_PALETTE
:
884 png_ptr
->channels
= 1;
887 case PNG_COLOR_TYPE_RGB
:
888 png_ptr
->channels
= 3;
891 case PNG_COLOR_TYPE_GRAY_ALPHA
:
892 png_ptr
->channels
= 2;
895 case PNG_COLOR_TYPE_RGB_ALPHA
:
896 png_ptr
->channels
= 4;
900 /* Set up other useful info */
901 png_ptr
->pixel_depth
= (png_byte
)(png_ptr
->bit_depth
* png_ptr
->channels
);
902 png_ptr
->rowbytes
= PNG_ROWBYTES(png_ptr
->pixel_depth
, png_ptr
->width
);
903 png_debug1(3, "bit_depth = %d", png_ptr
->bit_depth
);
904 png_debug1(3, "channels = %d", png_ptr
->channels
);
905 png_debug1(3, "rowbytes = %lu", (unsigned long)png_ptr
->rowbytes
);
906 png_set_IHDR(png_ptr
, info_ptr
, width
, height
, bit_depth
,
907 color_type
, interlace_type
, compression_type
, filter_type
);
910 /* Read and check the palette */
912 png_handle_PLTE(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
914 png_color palette
[PNG_MAX_PALETTE_LENGTH
];
915 int max_palette_length
, num
, i
;
916 #ifdef PNG_POINTER_INDEXING_SUPPORTED
920 png_debug(1, "in png_handle_PLTE");
922 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
923 png_chunk_error(png_ptr
, "missing IHDR");
925 /* Moved to before the 'after IDAT' check below because otherwise duplicate
926 * PLTE chunks are potentially ignored (the spec says there shall not be more
927 * than one PLTE, the error is not treated as benign, so this check trumps
928 * the requirement that PLTE appears before IDAT.)
930 else if ((png_ptr
->mode
& PNG_HAVE_PLTE
) != 0)
931 png_chunk_error(png_ptr
, "duplicate");
933 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
935 /* This is benign because the non-benign error happened before, when an
936 * IDAT was encountered in a color-mapped image with no PLTE.
938 png_crc_finish(png_ptr
, length
);
939 png_chunk_benign_error(png_ptr
, "out of place");
943 png_ptr
->mode
|= PNG_HAVE_PLTE
;
945 if ((png_ptr
->color_type
& PNG_COLOR_MASK_COLOR
) == 0)
947 png_crc_finish(png_ptr
, length
);
948 png_chunk_benign_error(png_ptr
, "ignored in grayscale PNG");
952 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
953 if (png_ptr
->color_type
!= PNG_COLOR_TYPE_PALETTE
)
955 png_crc_finish(png_ptr
, length
);
960 if (length
> 3*PNG_MAX_PALETTE_LENGTH
|| length
% 3)
962 png_crc_finish(png_ptr
, length
);
964 if (png_ptr
->color_type
!= PNG_COLOR_TYPE_PALETTE
)
965 png_chunk_benign_error(png_ptr
, "invalid");
968 png_chunk_error(png_ptr
, "invalid");
973 /* The cast is safe because 'length' is less than 3*PNG_MAX_PALETTE_LENGTH */
974 num
= (int)length
/ 3;
976 /* If the palette has 256 or fewer entries but is too large for the bit
977 * depth, we don't issue an error, to preserve the behavior of previous
978 * libpng versions. We silently truncate the unused extra palette entries
981 if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
982 max_palette_length
= (1 << png_ptr
->bit_depth
);
984 max_palette_length
= PNG_MAX_PALETTE_LENGTH
;
986 if (num
> max_palette_length
)
987 num
= max_palette_length
;
989 #ifdef PNG_POINTER_INDEXING_SUPPORTED
990 for (i
= 0, pal_ptr
= palette
; i
< num
; i
++, pal_ptr
++)
994 png_crc_read(png_ptr
, buf
, 3);
995 pal_ptr
->red
= buf
[0];
996 pal_ptr
->green
= buf
[1];
997 pal_ptr
->blue
= buf
[2];
1000 for (i
= 0; i
< num
; i
++)
1004 png_crc_read(png_ptr
, buf
, 3);
1005 /* Don't depend upon png_color being any order */
1006 palette
[i
].red
= buf
[0];
1007 palette
[i
].green
= buf
[1];
1008 palette
[i
].blue
= buf
[2];
1012 /* If we actually need the PLTE chunk (ie for a paletted image), we do
1013 * whatever the normal CRC configuration tells us. However, if we
1014 * have an RGB image, the PLTE can be considered ancillary, so
1015 * we will act as though it is.
1017 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
1018 if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
1021 png_crc_finish(png_ptr
, (png_uint_32
) (length
- (unsigned int)num
* 3));
1024 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
1025 else if (png_crc_error(png_ptr
) != 0) /* Only if we have a CRC error */
1027 /* If we don't want to use the data from an ancillary chunk,
1028 * we have two options: an error abort, or a warning and we
1029 * ignore the data in this chunk (which should be OK, since
1030 * it's considered ancillary for a RGB or RGBA image).
1032 * IMPLEMENTATION NOTE: this is only here because png_crc_finish uses the
1033 * chunk type to determine whether to check the ancillary or the critical
1036 if ((png_ptr
->flags
& PNG_FLAG_CRC_ANCILLARY_USE
) == 0)
1038 if ((png_ptr
->flags
& PNG_FLAG_CRC_ANCILLARY_NOWARN
) != 0)
1042 png_chunk_error(png_ptr
, "CRC error");
1045 /* Otherwise, we (optionally) emit a warning and use the chunk. */
1046 else if ((png_ptr
->flags
& PNG_FLAG_CRC_ANCILLARY_NOWARN
) == 0)
1047 png_chunk_warning(png_ptr
, "CRC error");
1051 /* TODO: png_set_PLTE has the side effect of setting png_ptr->palette to its
1052 * own copy of the palette. This has the side effect that when png_start_row
1053 * is called (this happens after any call to png_read_update_info) the
1054 * info_ptr palette gets changed. This is extremely unexpected and
1057 * Fix this by not sharing the palette in this way.
1059 png_set_PLTE(png_ptr
, info_ptr
, palette
, num
);
1061 /* The three chunks, bKGD, hIST and tRNS *must* appear after PLTE and before
1062 * IDAT. Prior to 1.6.0 this was not checked; instead the code merely
1063 * checked the apparent validity of a tRNS chunk inserted before PLTE on a
1064 * palette PNG. 1.6.0 attempts to rigorously follow the standard and
1065 * therefore does a benign error if the erroneous condition is detected *and*
1066 * cancels the tRNS if the benign error returns. The alternative is to
1067 * amend the standard since it would be rather hypocritical of the standards
1068 * maintainers to ignore it.
1070 #ifdef PNG_READ_tRNS_SUPPORTED
1071 if (png_ptr
->num_trans
> 0 ||
1072 (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_tRNS
) != 0))
1074 /* Cancel this because otherwise it would be used if the transforms
1075 * require it. Don't cancel the 'valid' flag because this would prevent
1076 * detection of duplicate chunks.
1078 png_ptr
->num_trans
= 0;
1080 if (info_ptr
!= NULL
)
1081 info_ptr
->num_trans
= 0;
1083 png_chunk_benign_error(png_ptr
, "tRNS must be after");
1087 #ifdef PNG_READ_hIST_SUPPORTED
1088 if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_hIST
) != 0)
1089 png_chunk_benign_error(png_ptr
, "hIST must be after");
1092 #ifdef PNG_READ_bKGD_SUPPORTED
1093 if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_bKGD
) != 0)
1094 png_chunk_benign_error(png_ptr
, "bKGD must be after");
1099 png_handle_IEND(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1101 png_debug(1, "in png_handle_IEND");
1103 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0 ||
1104 (png_ptr
->mode
& PNG_HAVE_IDAT
) == 0)
1105 png_chunk_error(png_ptr
, "out of place");
1107 png_ptr
->mode
|= (PNG_AFTER_IDAT
| PNG_HAVE_IEND
);
1109 png_crc_finish(png_ptr
, length
);
1112 png_chunk_benign_error(png_ptr
, "invalid");
1114 PNG_UNUSED(info_ptr
)
1117 #ifdef PNG_READ_gAMA_SUPPORTED
1119 png_handle_gAMA(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1121 png_fixed_point igamma
;
1124 png_debug(1, "in png_handle_gAMA");
1126 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1127 png_chunk_error(png_ptr
, "missing IHDR");
1129 else if ((png_ptr
->mode
& (PNG_HAVE_IDAT
|PNG_HAVE_PLTE
)) != 0)
1131 png_crc_finish(png_ptr
, length
);
1132 png_chunk_benign_error(png_ptr
, "out of place");
1138 png_crc_finish(png_ptr
, length
);
1139 png_chunk_benign_error(png_ptr
, "invalid");
1143 png_crc_read(png_ptr
, buf
, 4);
1145 if (png_crc_finish(png_ptr
, 0) != 0)
1148 igamma
= png_get_fixed_point(NULL
, buf
);
1150 png_colorspace_set_gamma(png_ptr
, &png_ptr
->colorspace
, igamma
);
1151 png_colorspace_sync(png_ptr
, info_ptr
);
1155 #ifdef PNG_READ_sBIT_SUPPORTED
1157 png_handle_sBIT(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1159 unsigned int truelen
, i
;
1160 png_byte sample_depth
;
1163 png_debug(1, "in png_handle_sBIT");
1165 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1166 png_chunk_error(png_ptr
, "missing IHDR");
1168 else if ((png_ptr
->mode
& (PNG_HAVE_IDAT
|PNG_HAVE_PLTE
)) != 0)
1170 png_crc_finish(png_ptr
, length
);
1171 png_chunk_benign_error(png_ptr
, "out of place");
1175 if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_sBIT
) != 0)
1177 png_crc_finish(png_ptr
, length
);
1178 png_chunk_benign_error(png_ptr
, "duplicate");
1182 if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
1190 truelen
= png_ptr
->channels
;
1191 sample_depth
= png_ptr
->bit_depth
;
1194 if (length
!= truelen
|| length
> 4)
1196 png_chunk_benign_error(png_ptr
, "invalid");
1197 png_crc_finish(png_ptr
, length
);
1201 buf
[0] = buf
[1] = buf
[2] = buf
[3] = sample_depth
;
1202 png_crc_read(png_ptr
, buf
, truelen
);
1204 if (png_crc_finish(png_ptr
, 0) != 0)
1207 for (i
=0; i
<truelen
; ++i
)
1209 if (buf
[i
] == 0 || buf
[i
] > sample_depth
)
1211 png_chunk_benign_error(png_ptr
, "invalid");
1216 if ((png_ptr
->color_type
& PNG_COLOR_MASK_COLOR
) != 0)
1218 png_ptr
->sig_bit
.red
= buf
[0];
1219 png_ptr
->sig_bit
.green
= buf
[1];
1220 png_ptr
->sig_bit
.blue
= buf
[2];
1221 png_ptr
->sig_bit
.alpha
= buf
[3];
1226 png_ptr
->sig_bit
.gray
= buf
[0];
1227 png_ptr
->sig_bit
.red
= buf
[0];
1228 png_ptr
->sig_bit
.green
= buf
[0];
1229 png_ptr
->sig_bit
.blue
= buf
[0];
1230 png_ptr
->sig_bit
.alpha
= buf
[1];
1233 png_set_sBIT(png_ptr
, info_ptr
, &(png_ptr
->sig_bit
));
1237 #ifdef PNG_READ_cHRM_SUPPORTED
1239 png_handle_cHRM(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1244 png_debug(1, "in png_handle_cHRM");
1246 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1247 png_chunk_error(png_ptr
, "missing IHDR");
1249 else if ((png_ptr
->mode
& (PNG_HAVE_IDAT
|PNG_HAVE_PLTE
)) != 0)
1251 png_crc_finish(png_ptr
, length
);
1252 png_chunk_benign_error(png_ptr
, "out of place");
1258 png_crc_finish(png_ptr
, length
);
1259 png_chunk_benign_error(png_ptr
, "invalid");
1263 png_crc_read(png_ptr
, buf
, 32);
1265 if (png_crc_finish(png_ptr
, 0) != 0)
1268 xy
.whitex
= png_get_fixed_point(NULL
, buf
);
1269 xy
.whitey
= png_get_fixed_point(NULL
, buf
+ 4);
1270 xy
.redx
= png_get_fixed_point(NULL
, buf
+ 8);
1271 xy
.redy
= png_get_fixed_point(NULL
, buf
+ 12);
1272 xy
.greenx
= png_get_fixed_point(NULL
, buf
+ 16);
1273 xy
.greeny
= png_get_fixed_point(NULL
, buf
+ 20);
1274 xy
.bluex
= png_get_fixed_point(NULL
, buf
+ 24);
1275 xy
.bluey
= png_get_fixed_point(NULL
, buf
+ 28);
1277 if (xy
.whitex
== PNG_FIXED_ERROR
||
1278 xy
.whitey
== PNG_FIXED_ERROR
||
1279 xy
.redx
== PNG_FIXED_ERROR
||
1280 xy
.redy
== PNG_FIXED_ERROR
||
1281 xy
.greenx
== PNG_FIXED_ERROR
||
1282 xy
.greeny
== PNG_FIXED_ERROR
||
1283 xy
.bluex
== PNG_FIXED_ERROR
||
1284 xy
.bluey
== PNG_FIXED_ERROR
)
1286 png_chunk_benign_error(png_ptr
, "invalid values");
1290 /* If a colorspace error has already been output skip this chunk */
1291 if ((png_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
) != 0)
1294 if ((png_ptr
->colorspace
.flags
& PNG_COLORSPACE_FROM_cHRM
) != 0)
1296 png_ptr
->colorspace
.flags
|= PNG_COLORSPACE_INVALID
;
1297 png_colorspace_sync(png_ptr
, info_ptr
);
1298 png_chunk_benign_error(png_ptr
, "duplicate");
1302 png_ptr
->colorspace
.flags
|= PNG_COLORSPACE_FROM_cHRM
;
1303 (void)png_colorspace_set_chromaticities(png_ptr
, &png_ptr
->colorspace
, &xy
,
1304 1/*prefer cHRM values*/);
1305 png_colorspace_sync(png_ptr
, info_ptr
);
1309 #ifdef PNG_READ_sRGB_SUPPORTED
1311 png_handle_sRGB(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1315 png_debug(1, "in png_handle_sRGB");
1317 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1318 png_chunk_error(png_ptr
, "missing IHDR");
1320 else if ((png_ptr
->mode
& (PNG_HAVE_IDAT
|PNG_HAVE_PLTE
)) != 0)
1322 png_crc_finish(png_ptr
, length
);
1323 png_chunk_benign_error(png_ptr
, "out of place");
1329 png_crc_finish(png_ptr
, length
);
1330 png_chunk_benign_error(png_ptr
, "invalid");
1334 png_crc_read(png_ptr
, &intent
, 1);
1336 if (png_crc_finish(png_ptr
, 0) != 0)
1339 /* If a colorspace error has already been output skip this chunk */
1340 if ((png_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
) != 0)
1343 /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
1346 if ((png_ptr
->colorspace
.flags
& PNG_COLORSPACE_HAVE_INTENT
) != 0)
1348 png_ptr
->colorspace
.flags
|= PNG_COLORSPACE_INVALID
;
1349 png_colorspace_sync(png_ptr
, info_ptr
);
1350 png_chunk_benign_error(png_ptr
, "too many profiles");
1354 (void)png_colorspace_set_sRGB(png_ptr
, &png_ptr
->colorspace
, intent
);
1355 png_colorspace_sync(png_ptr
, info_ptr
);
1357 #endif /* READ_sRGB */
1359 #ifdef PNG_READ_iCCP_SUPPORTED
1361 png_handle_iCCP(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1362 /* Note: this does not properly handle profiles that are > 64K under DOS */
1364 png_const_charp errmsg
= NULL
; /* error message output, or no error */
1365 int finished
= 0; /* crc checked */
1367 png_debug(1, "in png_handle_iCCP");
1369 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1370 png_chunk_error(png_ptr
, "missing IHDR");
1372 else if ((png_ptr
->mode
& (PNG_HAVE_IDAT
|PNG_HAVE_PLTE
)) != 0)
1374 png_crc_finish(png_ptr
, length
);
1375 png_chunk_benign_error(png_ptr
, "out of place");
1379 /* Consistent with all the above colorspace handling an obviously *invalid*
1380 * chunk is just ignored, so does not invalidate the color space. An
1381 * alternative is to set the 'invalid' flags at the start of this routine
1382 * and only clear them in they were not set before and all the tests pass.
1385 /* The keyword must be at least one character and there is a
1386 * terminator (0) byte and the compression method byte, and the
1387 * 'zlib' datastream is at least 11 bytes.
1391 png_crc_finish(png_ptr
, length
);
1392 png_chunk_benign_error(png_ptr
, "too short");
1396 /* If a colorspace error has already been output skip this chunk */
1397 if ((png_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
) != 0)
1399 png_crc_finish(png_ptr
, length
);
1403 /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
1406 if ((png_ptr
->colorspace
.flags
& PNG_COLORSPACE_HAVE_INTENT
) == 0)
1408 uInt read_length
, keyword_length
;
1411 /* Find the keyword; the keyword plus separator and compression method
1412 * bytes can be at most 81 characters long.
1414 read_length
= 81; /* maximum */
1415 if (read_length
> length
)
1416 read_length
= (uInt
)length
;
1418 png_crc_read(png_ptr
, (png_bytep
)keyword
, read_length
);
1419 length
-= read_length
;
1421 /* The minimum 'zlib' stream is assumed to be just the 2 byte header,
1422 * 5 bytes minimum 'deflate' stream, and the 4 byte checksum.
1426 png_crc_finish(png_ptr
, length
);
1427 png_chunk_benign_error(png_ptr
, "too short");
1432 while (keyword_length
< 80 && keyword_length
< read_length
&&
1433 keyword
[keyword_length
] != 0)
1436 /* TODO: make the keyword checking common */
1437 if (keyword_length
>= 1 && keyword_length
<= 79)
1439 /* We only understand '0' compression - deflate - so if we get a
1440 * different value we can't safely decode the chunk.
1442 if (keyword_length
+1 < read_length
&&
1443 keyword
[keyword_length
+1] == PNG_COMPRESSION_TYPE_BASE
)
1445 read_length
-= keyword_length
+2;
1447 if (png_inflate_claim(png_ptr
, png_iCCP
) == Z_OK
)
1449 Byte profile_header
[132]={0};
1450 Byte local_buffer
[PNG_INFLATE_BUF_SIZE
];
1451 png_alloc_size_t size
= (sizeof profile_header
);
1453 png_ptr
->zstream
.next_in
= (Bytef
*)keyword
+ (keyword_length
+2);
1454 png_ptr
->zstream
.avail_in
= read_length
;
1455 (void)png_inflate_read(png_ptr
, local_buffer
,
1456 (sizeof local_buffer
), &length
, profile_header
, &size
,
1457 0/*finish: don't, because the output is too small*/);
1461 /* We have the ICC profile header; do the basic header checks.
1463 png_uint_32 profile_length
= png_get_uint_32(profile_header
);
1465 if (png_icc_check_length(png_ptr
, &png_ptr
->colorspace
,
1466 keyword
, profile_length
) != 0)
1468 /* The length is apparently ok, so we can check the 132
1471 if (png_icc_check_header(png_ptr
, &png_ptr
->colorspace
,
1472 keyword
, profile_length
, profile_header
,
1473 png_ptr
->color_type
) != 0)
1475 /* Now read the tag table; a variable size buffer is
1476 * needed at this point, allocate one for the whole
1477 * profile. The header check has already validated
1478 * that none of this stuff will overflow.
1480 png_uint_32 tag_count
=
1481 png_get_uint_32(profile_header
+ 128);
1482 png_bytep profile
= png_read_buffer(png_ptr
,
1483 profile_length
, 2/*silent*/);
1485 if (profile
!= NULL
)
1487 memcpy(profile
, profile_header
,
1488 (sizeof profile_header
));
1490 size
= 12 * tag_count
;
1492 (void)png_inflate_read(png_ptr
, local_buffer
,
1493 (sizeof local_buffer
), &length
,
1494 profile
+ (sizeof profile_header
), &size
, 0);
1496 /* Still expect a buffer error because we expect
1497 * there to be some tag data!
1501 if (png_icc_check_tag_table(png_ptr
,
1502 &png_ptr
->colorspace
, keyword
, profile_length
,
1505 /* The profile has been validated for basic
1506 * security issues, so read the whole thing in.
1508 size
= profile_length
- (sizeof profile_header
)
1511 (void)png_inflate_read(png_ptr
, local_buffer
,
1512 (sizeof local_buffer
), &length
,
1513 profile
+ (sizeof profile_header
) +
1514 12 * tag_count
, &size
, 1/*finish*/);
1516 if (length
> 0 && !(png_ptr
->flags
&
1517 PNG_FLAG_BENIGN_ERRORS_WARN
))
1518 errmsg
= "extra compressed data";
1520 /* But otherwise allow extra data: */
1525 /* This can be handled completely, so
1528 png_chunk_warning(png_ptr
,
1529 "extra compressed data");
1532 png_crc_finish(png_ptr
, length
);
1535 # if defined(PNG_sRGB_SUPPORTED) && PNG_sRGB_PROFILE_CHECKS >= 0
1536 /* Check for a match against sRGB */
1537 png_icc_set_sRGB(png_ptr
,
1538 &png_ptr
->colorspace
, profile
,
1539 png_ptr
->zstream
.adler
);
1542 /* Steal the profile for info_ptr. */
1543 if (info_ptr
!= NULL
)
1545 png_free_data(png_ptr
, info_ptr
,
1548 info_ptr
->iccp_name
= png_voidcast(char*,
1549 png_malloc_base(png_ptr
,
1551 if (info_ptr
->iccp_name
!= NULL
)
1553 memcpy(info_ptr
->iccp_name
, keyword
,
1555 info_ptr
->iccp_proflen
=
1557 info_ptr
->iccp_profile
= profile
;
1558 png_ptr
->read_buffer
= NULL
; /*steal*/
1559 info_ptr
->free_me
|= PNG_FREE_ICCP
;
1560 info_ptr
->valid
|= PNG_INFO_iCCP
;
1565 png_ptr
->colorspace
.flags
|=
1566 PNG_COLORSPACE_INVALID
;
1567 errmsg
= "out of memory";
1571 /* else the profile remains in the read
1572 * buffer which gets reused for subsequent
1576 if (info_ptr
!= NULL
)
1577 png_colorspace_sync(png_ptr
, info_ptr
);
1581 png_ptr
->zowner
= 0;
1586 errmsg
= png_ptr
->zstream
.msg
;
1588 /* else png_icc_check_tag_table output an error */
1590 else /* profile truncated */
1591 errmsg
= png_ptr
->zstream
.msg
;
1595 errmsg
= "out of memory";
1598 /* else png_icc_check_header output an error */
1601 /* else png_icc_check_length output an error */
1604 else /* profile truncated */
1605 errmsg
= png_ptr
->zstream
.msg
;
1607 /* Release the stream */
1608 png_ptr
->zowner
= 0;
1611 else /* png_inflate_claim failed */
1612 errmsg
= png_ptr
->zstream
.msg
;
1616 errmsg
= "bad compression method"; /* or missing */
1620 errmsg
= "bad keyword";
1624 errmsg
= "too many profiles";
1626 /* Failure: the reason is in 'errmsg' */
1628 png_crc_finish(png_ptr
, length
);
1630 png_ptr
->colorspace
.flags
|= PNG_COLORSPACE_INVALID
;
1631 png_colorspace_sync(png_ptr
, info_ptr
);
1632 if (errmsg
!= NULL
) /* else already output */
1633 png_chunk_benign_error(png_ptr
, errmsg
);
1635 #endif /* READ_iCCP */
1637 #ifdef PNG_READ_sPLT_SUPPORTED
1639 png_handle_sPLT(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1640 /* Note: this does not properly handle chunks that are > 64K under DOS */
1642 png_bytep entry_start
, buffer
;
1643 png_sPLT_t new_palette
;
1645 png_uint_32 data_length
;
1647 png_uint_32 skip
= 0;
1651 png_debug(1, "in png_handle_sPLT");
1653 #ifdef PNG_USER_LIMITS_SUPPORTED
1654 if (png_ptr
->user_chunk_cache_max
!= 0)
1656 if (png_ptr
->user_chunk_cache_max
== 1)
1658 png_crc_finish(png_ptr
, length
);
1662 if (--png_ptr
->user_chunk_cache_max
== 1)
1664 png_warning(png_ptr
, "No space in chunk cache for sPLT");
1665 png_crc_finish(png_ptr
, length
);
1671 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1672 png_chunk_error(png_ptr
, "missing IHDR");
1674 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
1676 png_crc_finish(png_ptr
, length
);
1677 png_chunk_benign_error(png_ptr
, "out of place");
1681 #ifdef PNG_MAX_MALLOC_64K
1682 if (length
> 65535U)
1684 png_crc_finish(png_ptr
, length
);
1685 png_chunk_benign_error(png_ptr
, "too large to fit in memory");
1690 buffer
= png_read_buffer(png_ptr
, length
+1, 2/*silent*/);
1693 png_crc_finish(png_ptr
, length
);
1694 png_chunk_benign_error(png_ptr
, "out of memory");
1699 /* WARNING: this may break if size_t is less than 32 bits; it is assumed
1700 * that the PNG_MAX_MALLOC_64K test is enabled in this case, but this is a
1701 * potential breakage point if the types in pngconf.h aren't exactly right.
1703 png_crc_read(png_ptr
, buffer
, length
);
1705 if (png_crc_finish(png_ptr
, skip
) != 0)
1710 for (entry_start
= buffer
; *entry_start
; entry_start
++)
1711 /* Empty loop to find end of name */ ;
1715 /* A sample depth should follow the separator, and we should be on it */
1716 if (length
< 2U || entry_start
> buffer
+ (length
- 2U))
1718 png_warning(png_ptr
, "malformed sPLT chunk");
1722 new_palette
.depth
= *entry_start
++;
1723 entry_size
= (new_palette
.depth
== 8 ? 6 : 10);
1724 /* This must fit in a png_uint_32 because it is derived from the original
1725 * chunk data length.
1727 data_length
= length
- (png_uint_32
)(entry_start
- buffer
);
1729 /* Integrity-check the data length */
1730 if ((data_length
% (unsigned int)entry_size
) != 0)
1732 png_warning(png_ptr
, "sPLT chunk has bad length");
1736 dl
= (png_uint_32
)(data_length
/ (unsigned int)entry_size
);
1737 max_dl
= PNG_SIZE_MAX
/ (sizeof (png_sPLT_entry
));
1741 png_warning(png_ptr
, "sPLT chunk too long");
1745 new_palette
.nentries
= (png_int_32
)(data_length
/ (unsigned int)entry_size
);
1747 new_palette
.entries
= (png_sPLT_entryp
)png_malloc_warn(png_ptr
,
1748 (png_alloc_size_t
) new_palette
.nentries
* (sizeof (png_sPLT_entry
)));
1750 if (new_palette
.entries
== NULL
)
1752 png_warning(png_ptr
, "sPLT chunk requires too much memory");
1756 #ifdef PNG_POINTER_INDEXING_SUPPORTED
1757 for (i
= 0; i
< new_palette
.nentries
; i
++)
1759 pp
= new_palette
.entries
+ i
;
1761 if (new_palette
.depth
== 8)
1763 pp
->red
= *entry_start
++;
1764 pp
->green
= *entry_start
++;
1765 pp
->blue
= *entry_start
++;
1766 pp
->alpha
= *entry_start
++;
1771 pp
->red
= png_get_uint_16(entry_start
); entry_start
+= 2;
1772 pp
->green
= png_get_uint_16(entry_start
); entry_start
+= 2;
1773 pp
->blue
= png_get_uint_16(entry_start
); entry_start
+= 2;
1774 pp
->alpha
= png_get_uint_16(entry_start
); entry_start
+= 2;
1777 pp
->frequency
= png_get_uint_16(entry_start
); entry_start
+= 2;
1780 pp
= new_palette
.entries
;
1782 for (i
= 0; i
< new_palette
.nentries
; i
++)
1785 if (new_palette
.depth
== 8)
1787 pp
[i
].red
= *entry_start
++;
1788 pp
[i
].green
= *entry_start
++;
1789 pp
[i
].blue
= *entry_start
++;
1790 pp
[i
].alpha
= *entry_start
++;
1795 pp
[i
].red
= png_get_uint_16(entry_start
); entry_start
+= 2;
1796 pp
[i
].green
= png_get_uint_16(entry_start
); entry_start
+= 2;
1797 pp
[i
].blue
= png_get_uint_16(entry_start
); entry_start
+= 2;
1798 pp
[i
].alpha
= png_get_uint_16(entry_start
); entry_start
+= 2;
1801 pp
[i
].frequency
= png_get_uint_16(entry_start
); entry_start
+= 2;
1805 /* Discard all chunk data except the name and stash that */
1806 new_palette
.name
= (png_charp
)buffer
;
1808 png_set_sPLT(png_ptr
, info_ptr
, &new_palette
, 1);
1810 png_free(png_ptr
, new_palette
.entries
);
1812 #endif /* READ_sPLT */
1814 #ifdef PNG_READ_tRNS_SUPPORTED
1816 png_handle_tRNS(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1818 png_byte readbuf
[PNG_MAX_PALETTE_LENGTH
];
1820 png_debug(1, "in png_handle_tRNS");
1822 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1823 png_chunk_error(png_ptr
, "missing IHDR");
1825 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
1827 png_crc_finish(png_ptr
, length
);
1828 png_chunk_benign_error(png_ptr
, "out of place");
1832 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_tRNS
) != 0)
1834 png_crc_finish(png_ptr
, length
);
1835 png_chunk_benign_error(png_ptr
, "duplicate");
1839 if (png_ptr
->color_type
== PNG_COLOR_TYPE_GRAY
)
1845 png_crc_finish(png_ptr
, length
);
1846 png_chunk_benign_error(png_ptr
, "invalid");
1850 png_crc_read(png_ptr
, buf
, 2);
1851 png_ptr
->num_trans
= 1;
1852 png_ptr
->trans_color
.gray
= png_get_uint_16(buf
);
1855 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_RGB
)
1861 png_crc_finish(png_ptr
, length
);
1862 png_chunk_benign_error(png_ptr
, "invalid");
1866 png_crc_read(png_ptr
, buf
, length
);
1867 png_ptr
->num_trans
= 1;
1868 png_ptr
->trans_color
.red
= png_get_uint_16(buf
);
1869 png_ptr
->trans_color
.green
= png_get_uint_16(buf
+ 2);
1870 png_ptr
->trans_color
.blue
= png_get_uint_16(buf
+ 4);
1873 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
1875 if ((png_ptr
->mode
& PNG_HAVE_PLTE
) == 0)
1877 /* TODO: is this actually an error in the ISO spec? */
1878 png_crc_finish(png_ptr
, length
);
1879 png_chunk_benign_error(png_ptr
, "out of place");
1883 if (length
> (unsigned int) png_ptr
->num_palette
||
1884 length
> (unsigned int) PNG_MAX_PALETTE_LENGTH
||
1887 png_crc_finish(png_ptr
, length
);
1888 png_chunk_benign_error(png_ptr
, "invalid");
1892 png_crc_read(png_ptr
, readbuf
, length
);
1893 png_ptr
->num_trans
= (png_uint_16
)length
;
1898 png_crc_finish(png_ptr
, length
);
1899 png_chunk_benign_error(png_ptr
, "invalid with alpha channel");
1903 if (png_crc_finish(png_ptr
, 0) != 0)
1905 png_ptr
->num_trans
= 0;
1909 /* TODO: this is a horrible side effect in the palette case because the
1910 * png_struct ends up with a pointer to the tRNS buffer owned by the
1911 * png_info. Fix this.
1913 png_set_tRNS(png_ptr
, info_ptr
, readbuf
, png_ptr
->num_trans
,
1914 &(png_ptr
->trans_color
));
1918 #ifdef PNG_READ_bKGD_SUPPORTED
1920 png_handle_bKGD(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1922 unsigned int truelen
;
1924 png_color_16 background
;
1926 png_debug(1, "in png_handle_bKGD");
1928 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
1929 png_chunk_error(png_ptr
, "missing IHDR");
1931 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0 ||
1932 (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
&&
1933 (png_ptr
->mode
& PNG_HAVE_PLTE
) == 0))
1935 png_crc_finish(png_ptr
, length
);
1936 png_chunk_benign_error(png_ptr
, "out of place");
1940 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_bKGD
) != 0)
1942 png_crc_finish(png_ptr
, length
);
1943 png_chunk_benign_error(png_ptr
, "duplicate");
1947 if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
1950 else if ((png_ptr
->color_type
& PNG_COLOR_MASK_COLOR
) != 0)
1956 if (length
!= truelen
)
1958 png_crc_finish(png_ptr
, length
);
1959 png_chunk_benign_error(png_ptr
, "invalid");
1963 png_crc_read(png_ptr
, buf
, truelen
);
1965 if (png_crc_finish(png_ptr
, 0) != 0)
1968 /* We convert the index value into RGB components so that we can allow
1969 * arbitrary RGB values for background when we have transparency, and
1970 * so it is easy to determine the RGB values of the background color
1971 * from the info_ptr struct.
1973 if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
1975 background
.index
= buf
[0];
1977 if (info_ptr
!= NULL
&& info_ptr
->num_palette
!= 0)
1979 if (buf
[0] >= info_ptr
->num_palette
)
1981 png_chunk_benign_error(png_ptr
, "invalid index");
1985 background
.red
= (png_uint_16
)png_ptr
->palette
[buf
[0]].red
;
1986 background
.green
= (png_uint_16
)png_ptr
->palette
[buf
[0]].green
;
1987 background
.blue
= (png_uint_16
)png_ptr
->palette
[buf
[0]].blue
;
1991 background
.red
= background
.green
= background
.blue
= 0;
1993 background
.gray
= 0;
1996 else if ((png_ptr
->color_type
& PNG_COLOR_MASK_COLOR
) == 0) /* GRAY */
1998 if (png_ptr
->bit_depth
<= 8)
2000 if (buf
[0] != 0 || buf
[1] >= (unsigned int)(1 << png_ptr
->bit_depth
))
2002 png_chunk_benign_error(png_ptr
, "invalid gray level");
2007 background
.index
= 0;
2011 background
.gray
= png_get_uint_16(buf
);
2016 if (png_ptr
->bit_depth
<= 8)
2018 if (buf
[0] != 0 || buf
[2] != 0 || buf
[4] != 0)
2020 png_chunk_benign_error(png_ptr
, "invalid color");
2025 background
.index
= 0;
2026 background
.red
= png_get_uint_16(buf
);
2027 background
.green
= png_get_uint_16(buf
+ 2);
2028 background
.blue
= png_get_uint_16(buf
+ 4);
2029 background
.gray
= 0;
2032 png_set_bKGD(png_ptr
, info_ptr
, &background
);
2036 #ifdef PNG_READ_eXIf_SUPPORTED
2038 png_handle_eXIf(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2042 png_debug(1, "in png_handle_eXIf");
2044 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2045 png_chunk_error(png_ptr
, "missing IHDR");
2049 png_crc_finish(png_ptr
, length
);
2050 png_chunk_benign_error(png_ptr
, "too short");
2054 else if (info_ptr
== NULL
|| (info_ptr
->valid
& PNG_INFO_eXIf
) != 0)
2056 png_crc_finish(png_ptr
, length
);
2057 png_chunk_benign_error(png_ptr
, "duplicate");
2061 info_ptr
->free_me
|= PNG_FREE_EXIF
;
2063 info_ptr
->eXIf_buf
= png_voidcast(png_bytep
,
2064 png_malloc_warn(png_ptr
, length
));
2066 if (info_ptr
->eXIf_buf
== NULL
)
2068 png_crc_finish(png_ptr
, length
);
2069 png_chunk_benign_error(png_ptr
, "out of memory");
2073 for (i
= 0; i
< length
; i
++)
2076 png_crc_read(png_ptr
, buf
, 1);
2077 info_ptr
->eXIf_buf
[i
] = buf
[0];
2080 if ((buf
[0] != 'M' && buf
[0] != 'I') ||
2081 (info_ptr
->eXIf_buf
[0] != buf
[0]))
2083 png_crc_finish(png_ptr
, length
- 2);
2084 png_chunk_benign_error(png_ptr
, "incorrect byte-order specifier");
2085 png_free(png_ptr
, info_ptr
->eXIf_buf
);
2086 info_ptr
->eXIf_buf
= NULL
;
2092 if (png_crc_finish(png_ptr
, 0) == 0)
2093 png_set_eXIf_1(png_ptr
, info_ptr
, length
, info_ptr
->eXIf_buf
);
2095 png_free(png_ptr
, info_ptr
->eXIf_buf
);
2096 info_ptr
->eXIf_buf
= NULL
;
2100 #ifdef PNG_READ_hIST_SUPPORTED
2102 png_handle_hIST(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2104 unsigned int num
, i
;
2105 png_uint_16 readbuf
[PNG_MAX_PALETTE_LENGTH
];
2107 png_debug(1, "in png_handle_hIST");
2109 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2110 png_chunk_error(png_ptr
, "missing IHDR");
2112 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0 ||
2113 (png_ptr
->mode
& PNG_HAVE_PLTE
) == 0)
2115 png_crc_finish(png_ptr
, length
);
2116 png_chunk_benign_error(png_ptr
, "out of place");
2120 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_hIST
) != 0)
2122 png_crc_finish(png_ptr
, length
);
2123 png_chunk_benign_error(png_ptr
, "duplicate");
2129 if (length
!= num
* 2 ||
2130 num
!= (unsigned int)png_ptr
->num_palette
||
2131 num
> (unsigned int)PNG_MAX_PALETTE_LENGTH
)
2133 png_crc_finish(png_ptr
, length
);
2134 png_chunk_benign_error(png_ptr
, "invalid");
2138 for (i
= 0; i
< num
; i
++)
2142 png_crc_read(png_ptr
, buf
, 2);
2143 readbuf
[i
] = png_get_uint_16(buf
);
2146 if (png_crc_finish(png_ptr
, 0) != 0)
2149 png_set_hIST(png_ptr
, info_ptr
, readbuf
);
2153 #ifdef PNG_READ_pHYs_SUPPORTED
2155 png_handle_pHYs(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2158 png_uint_32 res_x
, res_y
;
2161 png_debug(1, "in png_handle_pHYs");
2163 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2164 png_chunk_error(png_ptr
, "missing IHDR");
2166 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2168 png_crc_finish(png_ptr
, length
);
2169 png_chunk_benign_error(png_ptr
, "out of place");
2173 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_pHYs
) != 0)
2175 png_crc_finish(png_ptr
, length
);
2176 png_chunk_benign_error(png_ptr
, "duplicate");
2182 png_crc_finish(png_ptr
, length
);
2183 png_chunk_benign_error(png_ptr
, "invalid");
2187 png_crc_read(png_ptr
, buf
, 9);
2189 if (png_crc_finish(png_ptr
, 0) != 0)
2192 res_x
= png_get_uint_32(buf
);
2193 res_y
= png_get_uint_32(buf
+ 4);
2195 png_set_pHYs(png_ptr
, info_ptr
, res_x
, res_y
, unit_type
);
2199 #ifdef PNG_READ_oFFs_SUPPORTED
2201 png_handle_oFFs(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2204 png_int_32 offset_x
, offset_y
;
2207 png_debug(1, "in png_handle_oFFs");
2209 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2210 png_chunk_error(png_ptr
, "missing IHDR");
2212 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2214 png_crc_finish(png_ptr
, length
);
2215 png_chunk_benign_error(png_ptr
, "out of place");
2219 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_oFFs
) != 0)
2221 png_crc_finish(png_ptr
, length
);
2222 png_chunk_benign_error(png_ptr
, "duplicate");
2228 png_crc_finish(png_ptr
, length
);
2229 png_chunk_benign_error(png_ptr
, "invalid");
2233 png_crc_read(png_ptr
, buf
, 9);
2235 if (png_crc_finish(png_ptr
, 0) != 0)
2238 offset_x
= png_get_int_32(buf
);
2239 offset_y
= png_get_int_32(buf
+ 4);
2241 png_set_oFFs(png_ptr
, info_ptr
, offset_x
, offset_y
, unit_type
);
2245 #ifdef PNG_READ_pCAL_SUPPORTED
2246 /* Read the pCAL chunk (described in the PNG Extensions document) */
2248 png_handle_pCAL(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2251 png_byte type
, nparams
;
2252 png_bytep buffer
, buf
, units
, endptr
;
2256 png_debug(1, "in png_handle_pCAL");
2258 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2259 png_chunk_error(png_ptr
, "missing IHDR");
2261 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2263 png_crc_finish(png_ptr
, length
);
2264 png_chunk_benign_error(png_ptr
, "out of place");
2268 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_pCAL
) != 0)
2270 png_crc_finish(png_ptr
, length
);
2271 png_chunk_benign_error(png_ptr
, "duplicate");
2275 png_debug1(2, "Allocating and reading pCAL chunk data (%u bytes)",
2278 buffer
= png_read_buffer(png_ptr
, length
+1, 2/*silent*/);
2282 png_crc_finish(png_ptr
, length
);
2283 png_chunk_benign_error(png_ptr
, "out of memory");
2287 png_crc_read(png_ptr
, buffer
, length
);
2289 if (png_crc_finish(png_ptr
, 0) != 0)
2292 buffer
[length
] = 0; /* Null terminate the last string */
2294 png_debug(3, "Finding end of pCAL purpose string");
2295 for (buf
= buffer
; *buf
; buf
++)
2298 endptr
= buffer
+ length
;
2300 /* We need to have at least 12 bytes after the purpose string
2301 * in order to get the parameter information.
2303 if (endptr
- buf
<= 12)
2305 png_chunk_benign_error(png_ptr
, "invalid");
2309 png_debug(3, "Reading pCAL X0, X1, type, nparams, and units");
2310 X0
= png_get_int_32((png_bytep
)buf
+1);
2311 X1
= png_get_int_32((png_bytep
)buf
+5);
2316 png_debug(3, "Checking pCAL equation type and number of parameters");
2317 /* Check that we have the right number of parameters for known
2320 if ((type
== PNG_EQUATION_LINEAR
&& nparams
!= 2) ||
2321 (type
== PNG_EQUATION_BASE_E
&& nparams
!= 3) ||
2322 (type
== PNG_EQUATION_ARBITRARY
&& nparams
!= 3) ||
2323 (type
== PNG_EQUATION_HYPERBOLIC
&& nparams
!= 4))
2325 png_chunk_benign_error(png_ptr
, "invalid parameter count");
2329 else if (type
>= PNG_EQUATION_LAST
)
2331 png_chunk_benign_error(png_ptr
, "unrecognized equation type");
2334 for (buf
= units
; *buf
; buf
++)
2335 /* Empty loop to move past the units string. */ ;
2337 png_debug(3, "Allocating pCAL parameters array");
2339 params
= png_voidcast(png_charpp
, png_malloc_warn(png_ptr
,
2340 nparams
* (sizeof (png_charp
))));
2344 png_chunk_benign_error(png_ptr
, "out of memory");
2348 /* Get pointers to the start of each parameter string. */
2349 for (i
= 0; i
< nparams
; i
++)
2351 buf
++; /* Skip the null string terminator from previous parameter. */
2353 png_debug1(3, "Reading pCAL parameter %d", i
);
2355 for (params
[i
] = (png_charp
)buf
; buf
<= endptr
&& *buf
!= 0; buf
++)
2356 /* Empty loop to move past each parameter string */ ;
2358 /* Make sure we haven't run out of data yet */
2361 png_free(png_ptr
, params
);
2362 png_chunk_benign_error(png_ptr
, "invalid data");
2367 png_set_pCAL(png_ptr
, info_ptr
, (png_charp
)buffer
, X0
, X1
, type
, nparams
,
2368 (png_charp
)units
, params
);
2370 png_free(png_ptr
, params
);
2374 #ifdef PNG_READ_sCAL_SUPPORTED
2375 /* Read the sCAL chunk */
2377 png_handle_sCAL(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2383 png_debug(1, "in png_handle_sCAL");
2385 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2386 png_chunk_error(png_ptr
, "missing IHDR");
2388 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2390 png_crc_finish(png_ptr
, length
);
2391 png_chunk_benign_error(png_ptr
, "out of place");
2395 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_sCAL
) != 0)
2397 png_crc_finish(png_ptr
, length
);
2398 png_chunk_benign_error(png_ptr
, "duplicate");
2402 /* Need unit type, width, \0, height: minimum 4 bytes */
2403 else if (length
< 4)
2405 png_crc_finish(png_ptr
, length
);
2406 png_chunk_benign_error(png_ptr
, "invalid");
2410 png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)",
2413 buffer
= png_read_buffer(png_ptr
, length
+1, 2/*silent*/);
2417 png_chunk_benign_error(png_ptr
, "out of memory");
2418 png_crc_finish(png_ptr
, length
);
2422 png_crc_read(png_ptr
, buffer
, length
);
2423 buffer
[length
] = 0; /* Null terminate the last string */
2425 if (png_crc_finish(png_ptr
, 0) != 0)
2428 /* Validate the unit. */
2429 if (buffer
[0] != 1 && buffer
[0] != 2)
2431 png_chunk_benign_error(png_ptr
, "invalid unit");
2435 /* Validate the ASCII numbers, need two ASCII numbers separated by
2436 * a '\0' and they need to fit exactly in the chunk data.
2441 if (png_check_fp_number((png_const_charp
)buffer
, length
, &state
, &i
) == 0 ||
2442 i
>= length
|| buffer
[i
++] != 0)
2443 png_chunk_benign_error(png_ptr
, "bad width format");
2445 else if (PNG_FP_IS_POSITIVE(state
) == 0)
2446 png_chunk_benign_error(png_ptr
, "non-positive width");
2453 if (png_check_fp_number((png_const_charp
)buffer
, length
,
2454 &state
, &i
) == 0 || i
!= length
)
2455 png_chunk_benign_error(png_ptr
, "bad height format");
2457 else if (PNG_FP_IS_POSITIVE(state
) == 0)
2458 png_chunk_benign_error(png_ptr
, "non-positive height");
2461 /* This is the (only) success case. */
2462 png_set_sCAL_s(png_ptr
, info_ptr
, buffer
[0],
2463 (png_charp
)buffer
+1, (png_charp
)buffer
+heighti
);
2468 #ifdef PNG_READ_tIME_SUPPORTED
2470 png_handle_tIME(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2475 png_debug(1, "in png_handle_tIME");
2477 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2478 png_chunk_error(png_ptr
, "missing IHDR");
2480 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_tIME
) != 0)
2482 png_crc_finish(png_ptr
, length
);
2483 png_chunk_benign_error(png_ptr
, "duplicate");
2487 if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2488 png_ptr
->mode
|= PNG_AFTER_IDAT
;
2492 png_crc_finish(png_ptr
, length
);
2493 png_chunk_benign_error(png_ptr
, "invalid");
2497 png_crc_read(png_ptr
, buf
, 7);
2499 if (png_crc_finish(png_ptr
, 0) != 0)
2502 mod_time
.second
= buf
[6];
2503 mod_time
.minute
= buf
[5];
2504 mod_time
.hour
= buf
[4];
2505 mod_time
.day
= buf
[3];
2506 mod_time
.month
= buf
[2];
2507 mod_time
.year
= png_get_uint_16(buf
);
2509 png_set_tIME(png_ptr
, info_ptr
, &mod_time
);
2513 #ifdef PNG_READ_tEXt_SUPPORTED
2514 /* Note: this does not properly handle chunks that are > 64K under DOS */
2516 png_handle_tEXt(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2522 png_uint_32 skip
= 0;
2524 png_debug(1, "in png_handle_tEXt");
2526 #ifdef PNG_USER_LIMITS_SUPPORTED
2527 if (png_ptr
->user_chunk_cache_max
!= 0)
2529 if (png_ptr
->user_chunk_cache_max
== 1)
2531 png_crc_finish(png_ptr
, length
);
2535 if (--png_ptr
->user_chunk_cache_max
== 1)
2537 png_crc_finish(png_ptr
, length
);
2538 png_chunk_benign_error(png_ptr
, "no space in chunk cache");
2544 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2545 png_chunk_error(png_ptr
, "missing IHDR");
2547 if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2548 png_ptr
->mode
|= PNG_AFTER_IDAT
;
2550 #ifdef PNG_MAX_MALLOC_64K
2551 if (length
> 65535U)
2553 png_crc_finish(png_ptr
, length
);
2554 png_chunk_benign_error(png_ptr
, "too large to fit in memory");
2559 buffer
= png_read_buffer(png_ptr
, length
+1, 1/*warn*/);
2563 png_chunk_benign_error(png_ptr
, "out of memory");
2567 png_crc_read(png_ptr
, buffer
, length
);
2569 if (png_crc_finish(png_ptr
, skip
) != 0)
2572 key
= (png_charp
)buffer
;
2575 for (text
= key
; *text
; text
++)
2576 /* Empty loop to find end of key */ ;
2578 if (text
!= key
+ length
)
2581 text_info
.compression
= PNG_TEXT_COMPRESSION_NONE
;
2582 text_info
.key
= key
;
2583 text_info
.lang
= NULL
;
2584 text_info
.lang_key
= NULL
;
2585 text_info
.itxt_length
= 0;
2586 text_info
.text
= text
;
2587 text_info
.text_length
= strlen(text
);
2589 if (png_set_text_2(png_ptr
, info_ptr
, &text_info
, 1) != 0)
2590 png_warning(png_ptr
, "Insufficient memory to process text chunk");
2594 #ifdef PNG_READ_zTXt_SUPPORTED
2595 /* Note: this does not correctly handle chunks that are > 64K under DOS */
2597 png_handle_zTXt(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2599 png_const_charp errmsg
= NULL
;
2601 png_uint_32 keyword_length
;
2603 png_debug(1, "in png_handle_zTXt");
2605 #ifdef PNG_USER_LIMITS_SUPPORTED
2606 if (png_ptr
->user_chunk_cache_max
!= 0)
2608 if (png_ptr
->user_chunk_cache_max
== 1)
2610 png_crc_finish(png_ptr
, length
);
2614 if (--png_ptr
->user_chunk_cache_max
== 1)
2616 png_crc_finish(png_ptr
, length
);
2617 png_chunk_benign_error(png_ptr
, "no space in chunk cache");
2623 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2624 png_chunk_error(png_ptr
, "missing IHDR");
2626 if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2627 png_ptr
->mode
|= PNG_AFTER_IDAT
;
2629 /* Note, "length" is sufficient here; we won't be adding
2630 * a null terminator later.
2632 buffer
= png_read_buffer(png_ptr
, length
, 2/*silent*/);
2636 png_crc_finish(png_ptr
, length
);
2637 png_chunk_benign_error(png_ptr
, "out of memory");
2641 png_crc_read(png_ptr
, buffer
, length
);
2643 if (png_crc_finish(png_ptr
, 0) != 0)
2646 /* TODO: also check that the keyword contents match the spec! */
2647 for (keyword_length
= 0;
2648 keyword_length
< length
&& buffer
[keyword_length
] != 0;
2650 /* Empty loop to find end of name */ ;
2652 if (keyword_length
> 79 || keyword_length
< 1)
2653 errmsg
= "bad keyword";
2655 /* zTXt must have some LZ data after the keyword, although it may expand to
2656 * zero bytes; we need a '\0' at the end of the keyword, the compression type
2659 else if (keyword_length
+ 3 > length
)
2660 errmsg
= "truncated";
2662 else if (buffer
[keyword_length
+1] != PNG_COMPRESSION_TYPE_BASE
)
2663 errmsg
= "unknown compression type";
2667 png_alloc_size_t uncompressed_length
= PNG_SIZE_MAX
;
2669 /* TODO: at present png_decompress_chunk imposes a single application
2670 * level memory limit, this should be split to different values for iCCP
2673 if (png_decompress_chunk(png_ptr
, length
, keyword_length
+2,
2674 &uncompressed_length
, 1/*terminate*/) == Z_STREAM_END
)
2678 if (png_ptr
->read_buffer
== NULL
)
2679 errmsg
="Read failure in png_handle_zTXt";
2682 /* It worked; png_ptr->read_buffer now looks like a tEXt chunk
2683 * except for the extra compression type byte and the fact that
2684 * it isn't necessarily '\0' terminated.
2686 buffer
= png_ptr
->read_buffer
;
2687 buffer
[uncompressed_length
+(keyword_length
+2)] = 0;
2689 text
.compression
= PNG_TEXT_COMPRESSION_zTXt
;
2690 text
.key
= (png_charp
)buffer
;
2691 text
.text
= (png_charp
)(buffer
+ keyword_length
+2);
2692 text
.text_length
= uncompressed_length
;
2693 text
.itxt_length
= 0;
2695 text
.lang_key
= NULL
;
2697 if (png_set_text_2(png_ptr
, info_ptr
, &text
, 1) != 0)
2698 errmsg
= "insufficient memory";
2703 errmsg
= png_ptr
->zstream
.msg
;
2707 png_chunk_benign_error(png_ptr
, errmsg
);
2711 #ifdef PNG_READ_iTXt_SUPPORTED
2712 /* Note: this does not correctly handle chunks that are > 64K under DOS */
2714 png_handle_iTXt(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2716 png_const_charp errmsg
= NULL
;
2718 png_uint_32 prefix_length
;
2720 png_debug(1, "in png_handle_iTXt");
2722 #ifdef PNG_USER_LIMITS_SUPPORTED
2723 if (png_ptr
->user_chunk_cache_max
!= 0)
2725 if (png_ptr
->user_chunk_cache_max
== 1)
2727 png_crc_finish(png_ptr
, length
);
2731 if (--png_ptr
->user_chunk_cache_max
== 1)
2733 png_crc_finish(png_ptr
, length
);
2734 png_chunk_benign_error(png_ptr
, "no space in chunk cache");
2740 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
2741 png_chunk_error(png_ptr
, "missing IHDR");
2743 if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
2744 png_ptr
->mode
|= PNG_AFTER_IDAT
;
2746 buffer
= png_read_buffer(png_ptr
, length
+1, 1/*warn*/);
2750 png_crc_finish(png_ptr
, length
);
2751 png_chunk_benign_error(png_ptr
, "out of memory");
2755 png_crc_read(png_ptr
, buffer
, length
);
2757 if (png_crc_finish(png_ptr
, 0) != 0)
2760 /* First the keyword. */
2761 for (prefix_length
=0;
2762 prefix_length
< length
&& buffer
[prefix_length
] != 0;
2766 /* Perform a basic check on the keyword length here. */
2767 if (prefix_length
> 79 || prefix_length
< 1)
2768 errmsg
= "bad keyword";
2770 /* Expect keyword, compression flag, compression type, language, translated
2771 * keyword (both may be empty but are 0 terminated) then the text, which may
2774 else if (prefix_length
+ 5 > length
)
2775 errmsg
= "truncated";
2777 else if (buffer
[prefix_length
+1] == 0 ||
2778 (buffer
[prefix_length
+1] == 1 &&
2779 buffer
[prefix_length
+2] == PNG_COMPRESSION_TYPE_BASE
))
2781 int compressed
= buffer
[prefix_length
+1] != 0;
2782 png_uint_32 language_offset
, translated_keyword_offset
;
2783 png_alloc_size_t uncompressed_length
= 0;
2785 /* Now the language tag */
2787 language_offset
= prefix_length
;
2789 for (; prefix_length
< length
&& buffer
[prefix_length
] != 0;
2793 /* WARNING: the length may be invalid here, this is checked below. */
2794 translated_keyword_offset
= ++prefix_length
;
2796 for (; prefix_length
< length
&& buffer
[prefix_length
] != 0;
2800 /* prefix_length should now be at the trailing '\0' of the translated
2801 * keyword, but it may already be over the end. None of this arithmetic
2802 * can overflow because chunks are at most 2^31 bytes long, but on 16-bit
2803 * systems the available allocation may overflow.
2807 if (compressed
== 0 && prefix_length
<= length
)
2808 uncompressed_length
= length
- prefix_length
;
2810 else if (compressed
!= 0 && prefix_length
< length
)
2812 uncompressed_length
= PNG_SIZE_MAX
;
2814 /* TODO: at present png_decompress_chunk imposes a single application
2815 * level memory limit, this should be split to different values for
2816 * iCCP and text chunks.
2818 if (png_decompress_chunk(png_ptr
, length
, prefix_length
,
2819 &uncompressed_length
, 1/*terminate*/) == Z_STREAM_END
)
2820 buffer
= png_ptr
->read_buffer
;
2823 errmsg
= png_ptr
->zstream
.msg
;
2827 errmsg
= "truncated";
2833 buffer
[uncompressed_length
+prefix_length
] = 0;
2835 if (compressed
== 0)
2836 text
.compression
= PNG_ITXT_COMPRESSION_NONE
;
2839 text
.compression
= PNG_ITXT_COMPRESSION_zTXt
;
2841 text
.key
= (png_charp
)buffer
;
2842 text
.lang
= (png_charp
)buffer
+ language_offset
;
2843 text
.lang_key
= (png_charp
)buffer
+ translated_keyword_offset
;
2844 text
.text
= (png_charp
)buffer
+ prefix_length
;
2845 text
.text_length
= 0;
2846 text
.itxt_length
= uncompressed_length
;
2848 if (png_set_text_2(png_ptr
, info_ptr
, &text
, 1) != 0)
2849 errmsg
= "insufficient memory";
2854 errmsg
= "bad compression info";
2857 png_chunk_benign_error(png_ptr
, errmsg
);
2861 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
2862 /* Utility function for png_handle_unknown; set up png_ptr::unknown_chunk */
2864 png_cache_unknown_chunk(png_structrp png_ptr
, png_uint_32 length
)
2866 png_alloc_size_t limit
= PNG_SIZE_MAX
;
2868 if (png_ptr
->unknown_chunk
.data
!= NULL
)
2870 png_free(png_ptr
, png_ptr
->unknown_chunk
.data
);
2871 png_ptr
->unknown_chunk
.data
= NULL
;
2874 # ifdef PNG_SET_USER_LIMITS_SUPPORTED
2875 if (png_ptr
->user_chunk_malloc_max
> 0 &&
2876 png_ptr
->user_chunk_malloc_max
< limit
)
2877 limit
= png_ptr
->user_chunk_malloc_max
;
2879 # elif PNG_USER_CHUNK_MALLOC_MAX > 0
2880 if (PNG_USER_CHUNK_MALLOC_MAX
< limit
)
2881 limit
= PNG_USER_CHUNK_MALLOC_MAX
;
2884 if (length
<= limit
)
2886 PNG_CSTRING_FROM_CHUNK(png_ptr
->unknown_chunk
.name
, png_ptr
->chunk_name
);
2887 /* The following is safe because of the PNG_SIZE_MAX init above */
2888 png_ptr
->unknown_chunk
.size
= (size_t)length
/*SAFE*/;
2889 /* 'mode' is a flag array, only the bottom four bits matter here */
2890 png_ptr
->unknown_chunk
.location
= (png_byte
)png_ptr
->mode
/*SAFE*/;
2893 png_ptr
->unknown_chunk
.data
= NULL
;
2897 /* Do a 'warn' here - it is handled below. */
2898 png_ptr
->unknown_chunk
.data
= png_voidcast(png_bytep
,
2899 png_malloc_warn(png_ptr
, length
));
2903 if (png_ptr
->unknown_chunk
.data
== NULL
&& length
> 0)
2905 /* This is benign because we clean up correctly */
2906 png_crc_finish(png_ptr
, length
);
2907 png_chunk_benign_error(png_ptr
, "unknown chunk exceeds memory limits");
2914 png_crc_read(png_ptr
, png_ptr
->unknown_chunk
.data
, length
);
2915 png_crc_finish(png_ptr
, 0);
2919 #endif /* READ_UNKNOWN_CHUNKS */
2921 /* Handle an unknown, or known but disabled, chunk */
2923 png_handle_unknown(png_structrp png_ptr
, png_inforp info_ptr
,
2924 png_uint_32 length
, int keep
)
2926 int handled
= 0; /* the chunk was handled */
2928 png_debug(1, "in png_handle_unknown");
2930 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
2931 /* NOTE: this code is based on the code in libpng-1.4.12 except for fixing
2932 * the bug which meant that setting a non-default behavior for a specific
2933 * chunk would be ignored (the default was always used unless a user
2934 * callback was installed).
2936 * 'keep' is the value from the png_chunk_unknown_handling, the setting for
2937 * this specific chunk_name, if PNG_HANDLE_AS_UNKNOWN_SUPPORTED, if not it
2938 * will always be PNG_HANDLE_CHUNK_AS_DEFAULT and it needs to be set here.
2939 * This is just an optimization to avoid multiple calls to the lookup
2942 # ifndef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
2943 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
2944 keep
= png_chunk_unknown_handling(png_ptr
, png_ptr
->chunk_name
);
2948 /* One of the following methods will read the chunk or skip it (at least one
2949 * of these is always defined because this is the only way to switch on
2950 * PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
2952 # ifdef PNG_READ_USER_CHUNKS_SUPPORTED
2953 /* The user callback takes precedence over the chunk keep value, but the
2954 * keep value is still required to validate a save of a critical chunk.
2956 if (png_ptr
->read_user_chunk_fn
!= NULL
)
2958 if (png_cache_unknown_chunk(png_ptr
, length
) != 0)
2960 /* Callback to user unknown chunk handler */
2961 int ret
= (*(png_ptr
->read_user_chunk_fn
))(png_ptr
,
2962 &png_ptr
->unknown_chunk
);
2965 * negative: An error occurred; png_chunk_error will be called.
2966 * zero: The chunk was not handled, the chunk will be discarded
2967 * unless png_set_keep_unknown_chunks has been used to set
2968 * a 'keep' behavior for this particular chunk, in which
2969 * case that will be used. A critical chunk will cause an
2970 * error at this point unless it is to be saved.
2971 * positive: The chunk was handled, libpng will ignore/discard it.
2974 png_chunk_error(png_ptr
, "error in user chunk");
2978 /* If the keep value is 'default' or 'never' override it, but
2979 * still error out on critical chunks unless the keep value is
2980 * 'always' While this is weird it is the behavior in 1.4.12.
2981 * A possible improvement would be to obey the value set for the
2982 * chunk, but this would be an API change that would probably
2983 * damage some applications.
2985 * The png_app_warning below catches the case that matters, where
2986 * the application has not set specific save or ignore for this
2987 * chunk or global save or ignore.
2989 if (keep
< PNG_HANDLE_CHUNK_IF_SAFE
)
2991 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
2992 if (png_ptr
->unknown_default
< PNG_HANDLE_CHUNK_IF_SAFE
)
2994 png_chunk_warning(png_ptr
, "Saving unknown chunk:");
2995 png_app_warning(png_ptr
,
2996 "forcing save of an unhandled chunk;"
2997 " please call png_set_keep_unknown_chunks");
2998 /* with keep = PNG_HANDLE_CHUNK_IF_SAFE */
3001 keep
= PNG_HANDLE_CHUNK_IF_SAFE
;
3005 else /* chunk was handled */
3008 /* Critical chunks can be safely discarded at this point. */
3009 keep
= PNG_HANDLE_CHUNK_NEVER
;
3014 keep
= PNG_HANDLE_CHUNK_NEVER
; /* insufficient memory */
3018 /* Use the SAVE_UNKNOWN_CHUNKS code or skip the chunk */
3019 # endif /* READ_USER_CHUNKS */
3021 # ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
3023 /* keep is currently just the per-chunk setting, if there was no
3024 * setting change it to the global default now (not that this may
3025 * still be AS_DEFAULT) then obtain the cache of the chunk if required,
3026 * if not simply skip the chunk.
3028 if (keep
== PNG_HANDLE_CHUNK_AS_DEFAULT
)
3029 keep
= png_ptr
->unknown_default
;
3031 if (keep
== PNG_HANDLE_CHUNK_ALWAYS
||
3032 (keep
== PNG_HANDLE_CHUNK_IF_SAFE
&&
3033 PNG_CHUNK_ANCILLARY(png_ptr
->chunk_name
)))
3035 if (png_cache_unknown_chunk(png_ptr
, length
) == 0)
3036 keep
= PNG_HANDLE_CHUNK_NEVER
;
3040 png_crc_finish(png_ptr
, length
);
3043 # ifndef PNG_READ_USER_CHUNKS_SUPPORTED
3044 # error no method to support READ_UNKNOWN_CHUNKS
3048 /* If here there is no read callback pointer set and no support is
3049 * compiled in to just save the unknown chunks, so simply skip this
3050 * chunk. If 'keep' is something other than AS_DEFAULT or NEVER then
3051 * the app has erroneously asked for unknown chunk saving when there
3054 if (keep
> PNG_HANDLE_CHUNK_NEVER
)
3055 png_app_error(png_ptr
, "no unknown chunk support available");
3057 png_crc_finish(png_ptr
, length
);
3061 # ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
3062 /* Now store the chunk in the chunk list if appropriate, and if the limits
3065 if (keep
== PNG_HANDLE_CHUNK_ALWAYS
||
3066 (keep
== PNG_HANDLE_CHUNK_IF_SAFE
&&
3067 PNG_CHUNK_ANCILLARY(png_ptr
->chunk_name
)))
3069 # ifdef PNG_USER_LIMITS_SUPPORTED
3070 switch (png_ptr
->user_chunk_cache_max
)
3073 png_ptr
->user_chunk_cache_max
= 1;
3074 png_chunk_benign_error(png_ptr
, "no space in chunk cache");
3077 /* NOTE: prior to 1.6.0 this case resulted in an unknown critical
3078 * chunk being skipped, now there will be a hard error below.
3082 default: /* not at limit */
3083 --(png_ptr
->user_chunk_cache_max
);
3085 case 0: /* no limit */
3086 # endif /* USER_LIMITS */
3087 /* Here when the limit isn't reached or when limits are compiled
3088 * out; store the chunk.
3090 png_set_unknown_chunks(png_ptr
, info_ptr
,
3091 &png_ptr
->unknown_chunk
, 1);
3093 # ifdef PNG_USER_LIMITS_SUPPORTED
3098 # else /* no store support: the chunk must be handled by the user callback */
3099 PNG_UNUSED(info_ptr
)
3102 /* Regardless of the error handling below the cached data (if any) can be
3103 * freed now. Notice that the data is not freed if there is a png_error, but
3104 * it will be freed by destroy_read_struct.
3106 if (png_ptr
->unknown_chunk
.data
!= NULL
)
3107 png_free(png_ptr
, png_ptr
->unknown_chunk
.data
);
3108 png_ptr
->unknown_chunk
.data
= NULL
;
3110 #else /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */
3111 /* There is no support to read an unknown chunk, so just skip it. */
3112 png_crc_finish(png_ptr
, length
);
3113 PNG_UNUSED(info_ptr
)
3115 #endif /* !READ_UNKNOWN_CHUNKS */
3117 /* Check for unhandled critical chunks */
3118 if (handled
== 0 && PNG_CHUNK_CRITICAL(png_ptr
->chunk_name
))
3119 png_chunk_error(png_ptr
, "unhandled critical chunk");
3122 /* This function is called to verify that a chunk name is valid.
3123 * This function can't have the "critical chunk check" incorporated
3124 * into it, since in the future we will need to be able to call user
3125 * functions to handle unknown critical chunks after we check that
3126 * the chunk name itself is valid.
3129 /* Bit hacking: the test for an invalid byte in the 4 byte chunk name is:
3131 * ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
3135 png_check_chunk_name(png_const_structrp png_ptr
, png_uint_32 chunk_name
)
3138 png_uint_32 cn
=chunk_name
;
3140 png_debug(1, "in png_check_chunk_name");
3142 for (i
=1; i
<=4; ++i
)
3146 if (c
< 65 || c
> 122 || (c
> 90 && c
< 97))
3147 png_chunk_error(png_ptr
, "invalid chunk type");
3154 png_check_chunk_length(png_const_structrp png_ptr
, png_uint_32 length
)
3156 png_alloc_size_t limit
= PNG_UINT_31_MAX
;
3158 # ifdef PNG_SET_USER_LIMITS_SUPPORTED
3159 if (png_ptr
->user_chunk_malloc_max
> 0 &&
3160 png_ptr
->user_chunk_malloc_max
< limit
)
3161 limit
= png_ptr
->user_chunk_malloc_max
;
3162 # elif PNG_USER_CHUNK_MALLOC_MAX > 0
3163 if (PNG_USER_CHUNK_MALLOC_MAX
< limit
)
3164 limit
= PNG_USER_CHUNK_MALLOC_MAX
;
3166 if (png_ptr
->chunk_name
== png_IDAT
)
3168 png_alloc_size_t idat_limit
= PNG_UINT_31_MAX
;
3170 (size_t)png_ptr
->width
3171 * (size_t)png_ptr
->channels
3172 * (png_ptr
->bit_depth
> 8? 2: 1)
3174 + (png_ptr
->interlaced
? 6: 0);
3175 if (png_ptr
->height
> PNG_UINT_32_MAX
/row_factor
)
3176 idat_limit
= PNG_UINT_31_MAX
;
3178 idat_limit
= png_ptr
->height
* row_factor
;
3179 row_factor
= row_factor
> 32566? 32566 : row_factor
;
3180 idat_limit
+= 6 + 5*(idat_limit
/row_factor
+1); /* zlib+deflate overhead */
3181 idat_limit
=idat_limit
< PNG_UINT_31_MAX
? idat_limit
: PNG_UINT_31_MAX
;
3182 limit
= limit
< idat_limit
? idat_limit
: limit
;
3187 png_debug2(0," length = %lu, limit = %lu",
3188 (unsigned long)length
,(unsigned long)limit
);
3189 png_benign_error(png_ptr
, "chunk data is too large");
3193 /* Combines the row recently read in with the existing pixels in the row. This
3194 * routine takes care of alpha and transparency if requested. This routine also
3195 * handles the two methods of progressive display of interlaced images,
3196 * depending on the 'display' value; if 'display' is true then the whole row
3197 * (dp) is filled from the start by replicating the available pixels. If
3198 * 'display' is false only those pixels present in the pass are filled in.
3201 png_combine_row(png_const_structrp png_ptr
, png_bytep dp
, int display
)
3203 unsigned int pixel_depth
= png_ptr
->transformed_pixel_depth
;
3204 png_const_bytep sp
= png_ptr
->row_buf
+ 1;
3205 png_alloc_size_t row_width
= png_ptr
->width
;
3206 unsigned int pass
= png_ptr
->pass
;
3207 png_bytep end_ptr
= 0;
3208 png_byte end_byte
= 0;
3209 unsigned int end_mask
;
3211 png_debug(1, "in png_combine_row");
3213 /* Added in 1.5.6: it should not be possible to enter this routine until at
3214 * least one row has been read from the PNG data and transformed.
3216 if (pixel_depth
== 0)
3217 png_error(png_ptr
, "internal row logic error");
3219 /* Added in 1.5.4: the pixel depth should match the information returned by
3220 * any call to png_read_update_info at this point. Do not continue if we got
3223 if (png_ptr
->info_rowbytes
!= 0 && png_ptr
->info_rowbytes
!=
3224 PNG_ROWBYTES(pixel_depth
, row_width
))
3225 png_error(png_ptr
, "internal row size calculation error");
3227 /* Don't expect this to ever happen: */
3229 png_error(png_ptr
, "internal row width error");
3231 /* Preserve the last byte in cases where only part of it will be overwritten,
3232 * the multiply below may overflow, we don't care because ANSI-C guarantees
3233 * we get the low bits.
3235 end_mask
= (pixel_depth
* row_width
) & 7;
3238 /* end_ptr == NULL is a flag to say do nothing */
3239 end_ptr
= dp
+ PNG_ROWBYTES(pixel_depth
, row_width
) - 1;
3240 end_byte
= *end_ptr
;
3241 # ifdef PNG_READ_PACKSWAP_SUPPORTED
3242 if ((png_ptr
->transformations
& PNG_PACKSWAP
) != 0)
3243 /* little-endian byte */
3244 end_mask
= (unsigned int)(0xff << end_mask
);
3246 else /* big-endian byte */
3248 end_mask
= 0xff >> end_mask
;
3249 /* end_mask is now the bits to *keep* from the destination row */
3252 /* For non-interlaced images this reduces to a memcpy(). A memcpy()
3253 * will also happen if interlacing isn't supported or if the application
3254 * does not call png_set_interlace_handling(). In the latter cases the
3255 * caller just gets a sequence of the unexpanded rows from each interlace
3258 #ifdef PNG_READ_INTERLACING_SUPPORTED
3259 if (png_ptr
->interlaced
!= 0 &&
3260 (png_ptr
->transformations
& PNG_INTERLACE
) != 0 &&
3261 pass
< 6 && (display
== 0 ||
3262 /* The following copies everything for 'display' on passes 0, 2 and 4. */
3263 (display
== 1 && (pass
& 1) != 0)))
3265 /* Narrow images may have no bits in a pass; the caller should handle
3266 * this, but this test is cheap:
3268 if (row_width
<= PNG_PASS_START_COL(pass
))
3271 if (pixel_depth
< 8)
3273 /* For pixel depths up to 4 bpp the 8-pixel mask can be expanded to fit
3274 * into 32 bits, then a single loop over the bytes using the four byte
3275 * values in the 32-bit mask can be used. For the 'display' option the
3276 * expanded mask may also not require any masking within a byte. To
3277 * make this work the PACKSWAP option must be taken into account - it
3278 * simply requires the pixels to be reversed in each byte.
3280 * The 'regular' case requires a mask for each of the first 6 passes,
3281 * the 'display' case does a copy for the even passes in the range
3282 * 0..6. This has already been handled in the test above.
3284 * The masks are arranged as four bytes with the first byte to use in
3285 * the lowest bits (little-endian) regardless of the order (PACKSWAP or
3286 * not) of the pixels in each byte.
3288 * NOTE: the whole of this logic depends on the caller of this function
3289 * only calling it on rows appropriate to the pass. This function only
3290 * understands the 'x' logic; the 'y' logic is handled by the caller.
3292 * The following defines allow generation of compile time constant bit
3293 * masks for each pixel depth and each possibility of swapped or not
3294 * swapped bytes. Pass 'p' is in the range 0..6; 'x', a pixel index,
3295 * is in the range 0..7; and the result is 1 if the pixel is to be
3296 * copied in the pass, 0 if not. 'S' is for the sparkle method, 'B'
3297 * for the block method.
3299 * With some compilers a compile time expression of the general form:
3301 * (shift >= 32) ? (a >> (shift-32)) : (b >> shift)
3303 * Produces warnings with values of 'shift' in the range 33 to 63
3304 * because the right hand side of the ?: expression is evaluated by
3305 * the compiler even though it isn't used. Microsoft Visual C (various
3306 * versions) and the Intel C compiler are known to do this. To avoid
3307 * this the following macros are used in 1.5.6. This is a temporary
3308 * solution to avoid destabilizing the code during the release process.
3310 # if PNG_USE_COMPILE_TIME_MASKS
3311 # define PNG_LSR(x,s) ((x)>>((s) & 0x1f))
3312 # define PNG_LSL(x,s) ((x)<<((s) & 0x1f))
3314 # define PNG_LSR(x,s) ((x)>>(s))
3315 # define PNG_LSL(x,s) ((x)<<(s))
3317 # define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\
3318 PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1)
3319 # define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\
3320 PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1)
3322 /* Return a mask for pass 'p' pixel 'x' at depth 'd'. The mask is
3323 * little endian - the first pixel is at bit 0 - however the extra
3324 * parameter 's' can be set to cause the mask position to be swapped
3325 * within each byte, to match the PNG format. This is done by XOR of
3326 * the shift with 7, 6 or 4 for bit depths 1, 2 and 4.
3328 # define PIXEL_MASK(p,x,d,s) \
3329 (PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0))))
3331 /* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask.
3333 # define S_MASKx(p,x,d,s) (S_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
3334 # define B_MASKx(p,x,d,s) (B_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
3336 /* Combine 8 of these to get the full mask. For the 1-bpp and 2-bpp
3337 * cases the result needs replicating, for the 4-bpp case the above
3338 * generates a full 32 bits.
3340 # define MASK_EXPAND(m,d) ((m)*((d)==1?0x01010101:((d)==2?0x00010001:1)))
3342 # define S_MASK(p,d,s) MASK_EXPAND(S_MASKx(p,0,d,s) + S_MASKx(p,1,d,s) +\
3343 S_MASKx(p,2,d,s) + S_MASKx(p,3,d,s) + S_MASKx(p,4,d,s) +\
3344 S_MASKx(p,5,d,s) + S_MASKx(p,6,d,s) + S_MASKx(p,7,d,s), d)
3346 # define B_MASK(p,d,s) MASK_EXPAND(B_MASKx(p,0,d,s) + B_MASKx(p,1,d,s) +\
3347 B_MASKx(p,2,d,s) + B_MASKx(p,3,d,s) + B_MASKx(p,4,d,s) +\
3348 B_MASKx(p,5,d,s) + B_MASKx(p,6,d,s) + B_MASKx(p,7,d,s), d)
3350 #if PNG_USE_COMPILE_TIME_MASKS
3351 /* Utility macros to construct all the masks for a depth/swap
3352 * combination. The 's' parameter says whether the format is PNG
3353 * (big endian bytes) or not. Only the three odd-numbered passes are
3354 * required for the display/block algorithm.
3356 # define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\
3357 S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) }
3359 # define B_MASKS(d,s) { B_MASK(1,d,s), B_MASK(3,d,s), B_MASK(5,d,s) }
3361 # define DEPTH_INDEX(d) ((d)==1?0:((d)==2?1:2))
3363 /* Hence the pre-compiled masks indexed by PACKSWAP (or not), depth and
3366 static const png_uint_32 row_mask
[2/*PACKSWAP*/][3/*depth*/][6] =
3368 /* Little-endian byte masks for PACKSWAP */
3369 { S_MASKS(1,0), S_MASKS(2,0), S_MASKS(4,0) },
3370 /* Normal (big-endian byte) masks - PNG format */
3371 { S_MASKS(1,1), S_MASKS(2,1), S_MASKS(4,1) }
3374 /* display_mask has only three entries for the odd passes, so index by
3377 static const png_uint_32 display_mask
[2][3][3] =
3379 /* Little-endian byte masks for PACKSWAP */
3380 { B_MASKS(1,0), B_MASKS(2,0), B_MASKS(4,0) },
3381 /* Normal (big-endian byte) masks - PNG format */
3382 { B_MASKS(1,1), B_MASKS(2,1), B_MASKS(4,1) }
3385 # define MASK(pass,depth,display,png)\
3386 ((display)?display_mask[png][DEPTH_INDEX(depth)][pass>>1]:\
3387 row_mask[png][DEPTH_INDEX(depth)][pass])
3389 #else /* !PNG_USE_COMPILE_TIME_MASKS */
3390 /* This is the runtime alternative: it seems unlikely that this will
3391 * ever be either smaller or faster than the compile time approach.
3393 # define MASK(pass,depth,display,png)\
3394 ((display)?B_MASK(pass,depth,png):S_MASK(pass,depth,png))
3395 #endif /* !USE_COMPILE_TIME_MASKS */
3397 /* Use the appropriate mask to copy the required bits. In some cases
3398 * the byte mask will be 0 or 0xff; optimize these cases. row_width is
3399 * the number of pixels, but the code copies bytes, so it is necessary
3400 * to special case the end.
3402 png_uint_32 pixels_per_byte
= 8 / pixel_depth
;
3405 # ifdef PNG_READ_PACKSWAP_SUPPORTED
3406 if ((png_ptr
->transformations
& PNG_PACKSWAP
) != 0)
3407 mask
= MASK(pass
, pixel_depth
, display
, 0);
3411 mask
= MASK(pass
, pixel_depth
, display
, 1);
3417 /* It doesn't matter in the following if png_uint_32 has more than
3418 * 32 bits because the high bits always match those in m<<24; it is,
3419 * however, essential to use OR here, not +, because of this.
3422 mask
= (m
>> 8) | (m
<< 24); /* rotate right to good compilers */
3425 if (m
!= 0) /* something to copy */
3428 *dp
= (png_byte
)((*dp
& ~m
) | (*sp
& m
));
3433 /* NOTE: this may overwrite the last byte with garbage if the image
3434 * is not an exact number of bytes wide; libpng has always done
3437 if (row_width
<= pixels_per_byte
)
3438 break; /* May need to restore part of the last byte */
3440 row_width
-= pixels_per_byte
;
3446 else /* pixel_depth >= 8 */
3448 unsigned int bytes_to_copy
, bytes_to_jump
;
3450 /* Validate the depth - it must be a multiple of 8 */
3451 if (pixel_depth
& 7)
3452 png_error(png_ptr
, "invalid user transform pixel depth");
3454 pixel_depth
>>= 3; /* now in bytes */
3455 row_width
*= pixel_depth
;
3457 /* Regardless of pass number the Adam 7 interlace always results in a
3458 * fixed number of pixels to copy then to skip. There may be a
3459 * different number of pixels to skip at the start though.
3462 unsigned int offset
= PNG_PASS_START_COL(pass
) * pixel_depth
;
3464 row_width
-= offset
;
3469 /* Work out the bytes to copy. */
3472 /* When doing the 'block' algorithm the pixel in the pass gets
3473 * replicated to adjacent pixels. This is why the even (0,2,4,6)
3474 * passes are skipped above - the entire expanded row is copied.
3476 bytes_to_copy
= (1<<((6-pass
)>>1)) * pixel_depth
;
3478 /* But don't allow this number to exceed the actual row width. */
3479 if (bytes_to_copy
> row_width
)
3480 bytes_to_copy
= (unsigned int)/*SAFE*/row_width
;
3483 else /* normal row; Adam7 only ever gives us one pixel to copy. */
3484 bytes_to_copy
= pixel_depth
;
3486 /* In Adam7 there is a constant offset between where the pixels go. */
3487 bytes_to_jump
= PNG_PASS_COL_OFFSET(pass
) * pixel_depth
;
3489 /* And simply copy these bytes. Some optimization is possible here,
3490 * depending on the value of 'bytes_to_copy'. Special case the low
3491 * byte counts, which we know to be frequent.
3493 * Notice that these cases all 'return' rather than 'break' - this
3494 * avoids an unnecessary test on whether to restore the last byte
3497 switch (bytes_to_copy
)
3504 if (row_width
<= bytes_to_jump
)
3507 dp
+= bytes_to_jump
;
3508 sp
+= bytes_to_jump
;
3509 row_width
-= bytes_to_jump
;
3513 /* There is a possibility of a partial copy at the end here; this
3514 * slows the code down somewhat.
3518 dp
[0] = sp
[0]; dp
[1] = sp
[1];
3520 if (row_width
<= bytes_to_jump
)
3523 sp
+= bytes_to_jump
;
3524 dp
+= bytes_to_jump
;
3525 row_width
-= bytes_to_jump
;
3527 while (row_width
> 1);
3529 /* And there can only be one byte left at this point: */
3534 /* This can only be the RGB case, so each copy is exactly one
3535 * pixel and it is not necessary to check for a partial copy.
3539 dp
[0] = sp
[0]; dp
[1] = sp
[1]; dp
[2] = sp
[2];
3541 if (row_width
<= bytes_to_jump
)
3544 sp
+= bytes_to_jump
;
3545 dp
+= bytes_to_jump
;
3546 row_width
-= bytes_to_jump
;
3550 #if PNG_ALIGN_TYPE != PNG_ALIGN_NONE
3551 /* Check for double byte alignment and, if possible, use a
3552 * 16-bit copy. Don't attempt this for narrow images - ones that
3553 * are less than an interlace panel wide. Don't attempt it for
3554 * wide bytes_to_copy either - use the memcpy there.
3556 if (bytes_to_copy
< 16 /*else use memcpy*/ &&
3557 png_isaligned(dp
, png_uint_16
) &&
3558 png_isaligned(sp
, png_uint_16
) &&
3559 bytes_to_copy
% (sizeof (png_uint_16
)) == 0 &&
3560 bytes_to_jump
% (sizeof (png_uint_16
)) == 0)
3562 /* Everything is aligned for png_uint_16 copies, but try for
3563 * png_uint_32 first.
3565 if (png_isaligned(dp
, png_uint_32
) &&
3566 png_isaligned(sp
, png_uint_32
) &&
3567 bytes_to_copy
% (sizeof (png_uint_32
)) == 0 &&
3568 bytes_to_jump
% (sizeof (png_uint_32
)) == 0)
3570 png_uint_32p dp32
= png_aligncast(png_uint_32p
,dp
);
3571 png_const_uint_32p sp32
= png_aligncastconst(
3572 png_const_uint_32p
, sp
);
3573 size_t skip
= (bytes_to_jump
-bytes_to_copy
) /
3574 (sizeof (png_uint_32
));
3578 size_t c
= bytes_to_copy
;
3582 c
-= (sizeof (png_uint_32
));
3586 if (row_width
<= bytes_to_jump
)
3591 row_width
-= bytes_to_jump
;
3593 while (bytes_to_copy
<= row_width
);
3595 /* Get to here when the row_width truncates the final copy.
3596 * There will be 1-3 bytes left to copy, so don't try the
3597 * 16-bit loop below.
3599 dp
= (png_bytep
)dp32
;
3600 sp
= (png_const_bytep
)sp32
;
3603 while (--row_width
> 0);
3607 /* Else do it in 16-bit quantities, but only if the size is
3612 png_uint_16p dp16
= png_aligncast(png_uint_16p
, dp
);
3613 png_const_uint_16p sp16
= png_aligncastconst(
3614 png_const_uint_16p
, sp
);
3615 size_t skip
= (bytes_to_jump
-bytes_to_copy
) /
3616 (sizeof (png_uint_16
));
3620 size_t c
= bytes_to_copy
;
3624 c
-= (sizeof (png_uint_16
));
3628 if (row_width
<= bytes_to_jump
)
3633 row_width
-= bytes_to_jump
;
3635 while (bytes_to_copy
<= row_width
);
3637 /* End of row - 1 byte left, bytes_to_copy > row_width: */
3638 dp
= (png_bytep
)dp16
;
3639 sp
= (png_const_bytep
)sp16
;
3642 while (--row_width
> 0);
3646 #endif /* ALIGN_TYPE code */
3648 /* The true default - use a memcpy: */
3651 memcpy(dp
, sp
, bytes_to_copy
);
3653 if (row_width
<= bytes_to_jump
)
3656 sp
+= bytes_to_jump
;
3657 dp
+= bytes_to_jump
;
3658 row_width
-= bytes_to_jump
;
3659 if (bytes_to_copy
> row_width
)
3660 bytes_to_copy
= (unsigned int)/*SAFE*/row_width
;
3665 } /* pixel_depth >= 8 */
3667 /* Here if pixel_depth < 8 to check 'end_ptr' below. */
3670 #endif /* READ_INTERLACING */
3672 /* If here then the switch above wasn't used so just memcpy the whole row
3673 * from the temporary row buffer (notice that this overwrites the end of the
3674 * destination row if it is a partial byte.)
3676 memcpy(dp
, sp
, PNG_ROWBYTES(pixel_depth
, row_width
));
3678 /* Restore the overwritten bits from the last byte if necessary. */
3679 if (end_ptr
!= NULL
)
3680 *end_ptr
= (png_byte
)((end_byte
& end_mask
) | (*end_ptr
& ~end_mask
));
3683 #ifdef PNG_READ_INTERLACING_SUPPORTED
3685 png_do_read_interlace(png_row_infop row_info
, png_bytep row
, int pass
,
3686 png_uint_32 transformations
/* Because these may affect the byte layout */)
3688 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
3689 /* Offset to next interlace block */
3690 static const unsigned int png_pass_inc
[7] = {8, 8, 4, 4, 2, 2, 1};
3692 png_debug(1, "in png_do_read_interlace");
3693 if (row
!= NULL
&& row_info
!= NULL
)
3695 png_uint_32 final_width
;
3697 final_width
= row_info
->width
* png_pass_inc
[pass
];
3699 switch (row_info
->pixel_depth
)
3703 png_bytep sp
= row
+ (size_t)((row_info
->width
- 1) >> 3);
3704 png_bytep dp
= row
+ (size_t)((final_width
- 1) >> 3);
3705 unsigned int sshift
, dshift
;
3706 unsigned int s_start
, s_end
;
3708 int jstop
= (int)png_pass_inc
[pass
];
3713 #ifdef PNG_READ_PACKSWAP_SUPPORTED
3714 if ((transformations
& PNG_PACKSWAP
) != 0)
3716 sshift
= ((row_info
->width
+ 7) & 0x07);
3717 dshift
= ((final_width
+ 7) & 0x07);
3726 sshift
= 7 - ((row_info
->width
+ 7) & 0x07);
3727 dshift
= 7 - ((final_width
+ 7) & 0x07);
3733 for (i
= 0; i
< row_info
->width
; i
++)
3735 v
= (png_byte
)((*sp
>> sshift
) & 0x01);
3736 for (j
= 0; j
< jstop
; j
++)
3738 unsigned int tmp
= *dp
& (0x7f7f >> (7 - dshift
));
3739 tmp
|= (unsigned int)(v
<< dshift
);
3740 *dp
= (png_byte
)(tmp
& 0xff);
3742 if (dshift
== s_end
)
3749 dshift
= (unsigned int)((int)dshift
+ s_inc
);
3752 if (sshift
== s_end
)
3759 sshift
= (unsigned int)((int)sshift
+ s_inc
);
3766 png_bytep sp
= row
+ (png_uint_32
)((row_info
->width
- 1) >> 2);
3767 png_bytep dp
= row
+ (png_uint_32
)((final_width
- 1) >> 2);
3768 unsigned int sshift
, dshift
;
3769 unsigned int s_start
, s_end
;
3771 int jstop
= (int)png_pass_inc
[pass
];
3774 #ifdef PNG_READ_PACKSWAP_SUPPORTED
3775 if ((transformations
& PNG_PACKSWAP
) != 0)
3777 sshift
= (((row_info
->width
+ 3) & 0x03) << 1);
3778 dshift
= (((final_width
+ 3) & 0x03) << 1);
3787 sshift
= ((3 - ((row_info
->width
+ 3) & 0x03)) << 1);
3788 dshift
= ((3 - ((final_width
+ 3) & 0x03)) << 1);
3794 for (i
= 0; i
< row_info
->width
; i
++)
3799 v
= (png_byte
)((*sp
>> sshift
) & 0x03);
3800 for (j
= 0; j
< jstop
; j
++)
3802 unsigned int tmp
= *dp
& (0x3f3f >> (6 - dshift
));
3803 tmp
|= (unsigned int)(v
<< dshift
);
3804 *dp
= (png_byte
)(tmp
& 0xff);
3806 if (dshift
== s_end
)
3813 dshift
= (unsigned int)((int)dshift
+ s_inc
);
3816 if (sshift
== s_end
)
3823 sshift
= (unsigned int)((int)sshift
+ s_inc
);
3830 png_bytep sp
= row
+ (size_t)((row_info
->width
- 1) >> 1);
3831 png_bytep dp
= row
+ (size_t)((final_width
- 1) >> 1);
3832 unsigned int sshift
, dshift
;
3833 unsigned int s_start
, s_end
;
3836 int jstop
= (int)png_pass_inc
[pass
];
3838 #ifdef PNG_READ_PACKSWAP_SUPPORTED
3839 if ((transformations
& PNG_PACKSWAP
) != 0)
3841 sshift
= (((row_info
->width
+ 1) & 0x01) << 2);
3842 dshift
= (((final_width
+ 1) & 0x01) << 2);
3851 sshift
= ((1 - ((row_info
->width
+ 1) & 0x01)) << 2);
3852 dshift
= ((1 - ((final_width
+ 1) & 0x01)) << 2);
3858 for (i
= 0; i
< row_info
->width
; i
++)
3860 png_byte v
= (png_byte
)((*sp
>> sshift
) & 0x0f);
3863 for (j
= 0; j
< jstop
; j
++)
3865 unsigned int tmp
= *dp
& (0xf0f >> (4 - dshift
));
3866 tmp
|= (unsigned int)(v
<< dshift
);
3867 *dp
= (png_byte
)(tmp
& 0xff);
3869 if (dshift
== s_end
)
3876 dshift
= (unsigned int)((int)dshift
+ s_inc
);
3879 if (sshift
== s_end
)
3886 sshift
= (unsigned int)((int)sshift
+ s_inc
);
3893 size_t pixel_bytes
= (row_info
->pixel_depth
>> 3);
3895 png_bytep sp
= row
+ (size_t)(row_info
->width
- 1)
3898 png_bytep dp
= row
+ (size_t)(final_width
- 1) * pixel_bytes
;
3900 int jstop
= (int)png_pass_inc
[pass
];
3903 for (i
= 0; i
< row_info
->width
; i
++)
3905 png_byte v
[8]; /* SAFE; pixel_depth does not exceed 64 */
3908 memcpy(v
, sp
, pixel_bytes
);
3910 for (j
= 0; j
< jstop
; j
++)
3912 memcpy(dp
, v
, pixel_bytes
);
3922 row_info
->width
= final_width
;
3923 row_info
->rowbytes
= PNG_ROWBYTES(row_info
->pixel_depth
, final_width
);
3925 #ifndef PNG_READ_PACKSWAP_SUPPORTED
3926 PNG_UNUSED(transformations
) /* Silence compiler warning */
3929 #endif /* READ_INTERLACING */
3932 png_read_filter_row_sub(png_row_infop row_info
, png_bytep row
,
3933 png_const_bytep prev_row
)
3936 size_t istop
= row_info
->rowbytes
;
3937 unsigned int bpp
= (row_info
->pixel_depth
+ 7) >> 3;
3938 png_bytep rp
= row
+ bpp
;
3940 PNG_UNUSED(prev_row
)
3942 for (i
= bpp
; i
< istop
; i
++)
3944 *rp
= (png_byte
)(((int)(*rp
) + (int)(*(rp
-bpp
))) & 0xff);
3950 png_read_filter_row_up(png_row_infop row_info
, png_bytep row
,
3951 png_const_bytep prev_row
)
3954 size_t istop
= row_info
->rowbytes
;
3956 png_const_bytep pp
= prev_row
;
3958 for (i
= 0; i
< istop
; i
++)
3960 *rp
= (png_byte
)(((int)(*rp
) + (int)(*pp
++)) & 0xff);
3966 png_read_filter_row_avg(png_row_infop row_info
, png_bytep row
,
3967 png_const_bytep prev_row
)
3971 png_const_bytep pp
= prev_row
;
3972 unsigned int bpp
= (row_info
->pixel_depth
+ 7) >> 3;
3973 size_t istop
= row_info
->rowbytes
- bpp
;
3975 for (i
= 0; i
< bpp
; i
++)
3977 *rp
= (png_byte
)(((int)(*rp
) +
3978 ((int)(*pp
++) / 2 )) & 0xff);
3983 for (i
= 0; i
< istop
; i
++)
3985 *rp
= (png_byte
)(((int)(*rp
) +
3986 (int)(*pp
++ + *(rp
-bpp
)) / 2 ) & 0xff);
3993 png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info
, png_bytep row
,
3994 png_const_bytep prev_row
)
3996 png_bytep rp_end
= row
+ row_info
->rowbytes
;
3999 /* First pixel/byte */
4002 *row
++ = (png_byte
)a
;
4005 while (row
< rp_end
)
4007 int b
, pa
, pb
, pc
, p
;
4009 a
&= 0xff; /* From previous iteration or start */
4020 pa
= p
< 0 ? -p
: p
;
4021 pb
= pc
< 0 ? -pc
: pc
;
4022 pc
= (p
+ pc
) < 0 ? -(p
+ pc
) : p
+ pc
;
4025 /* Find the best predictor, the least of pa, pb, pc favoring the earlier
4026 * ones in the case of a tie.
4034 /* Calculate the current pixel in a, and move the previous row pixel to c
4035 * for the next time round the loop
4039 *row
++ = (png_byte
)a
;
4044 png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info
, png_bytep row
,
4045 png_const_bytep prev_row
)
4047 unsigned int bpp
= (row_info
->pixel_depth
+ 7) >> 3;
4048 png_bytep rp_end
= row
+ bpp
;
4050 /* Process the first pixel in the row completely (this is the same as 'up'
4051 * because there is only one candidate predictor for the first row).
4053 while (row
< rp_end
)
4055 int a
= *row
+ *prev_row
++;
4056 *row
++ = (png_byte
)a
;
4060 rp_end
= rp_end
+ (row_info
->rowbytes
- bpp
);
4062 while (row
< rp_end
)
4064 int a
, b
, c
, pa
, pb
, pc
, p
;
4066 c
= *(prev_row
- bpp
);
4078 pa
= p
< 0 ? -p
: p
;
4079 pb
= pc
< 0 ? -pc
: pc
;
4080 pc
= (p
+ pc
) < 0 ? -(p
+ pc
) : p
+ pc
;
4090 *row
++ = (png_byte
)a
;
4095 png_init_filter_functions(png_structrp pp
)
4096 /* This function is called once for every PNG image (except for PNG images
4097 * that only use PNG_FILTER_VALUE_NONE for all rows) to set the
4098 * implementations required to reverse the filtering of PNG rows. Reversing
4099 * the filter is the first transformation performed on the row data. It is
4100 * performed in place, therefore an implementation can be selected based on
4101 * the image pixel format. If the implementation depends on image width then
4102 * take care to ensure that it works correctly if the image is interlaced -
4103 * interlacing causes the actual row width to vary.
4106 unsigned int bpp
= (pp
->pixel_depth
+ 7) >> 3;
4108 pp
->read_filter
[PNG_FILTER_VALUE_SUB
-1] = png_read_filter_row_sub
;
4109 pp
->read_filter
[PNG_FILTER_VALUE_UP
-1] = png_read_filter_row_up
;
4110 pp
->read_filter
[PNG_FILTER_VALUE_AVG
-1] = png_read_filter_row_avg
;
4112 pp
->read_filter
[PNG_FILTER_VALUE_PAETH
-1] =
4113 png_read_filter_row_paeth_1byte_pixel
;
4115 pp
->read_filter
[PNG_FILTER_VALUE_PAETH
-1] =
4116 png_read_filter_row_paeth_multibyte_pixel
;
4118 #ifdef PNG_FILTER_OPTIMIZATIONS
4119 /* To use this define PNG_FILTER_OPTIMIZATIONS as the name of a function to
4120 * call to install hardware optimizations for the above functions; simply
4121 * replace whatever elements of the pp->read_filter[] array with a hardware
4122 * specific (or, for that matter, generic) optimization.
4124 * To see an example of this examine what configure.ac does when
4125 * --enable-arm-neon is specified on the command line.
4127 PNG_FILTER_OPTIMIZATIONS(pp
, bpp
);
4132 png_read_filter_row(png_structrp pp
, png_row_infop row_info
, png_bytep row
,
4133 png_const_bytep prev_row
, int filter
)
4135 /* OPTIMIZATION: DO NOT MODIFY THIS FUNCTION, instead #define
4136 * PNG_FILTER_OPTIMIZATIONS to a function that overrides the generic
4137 * implementations. See png_init_filter_functions above.
4139 if (filter
> PNG_FILTER_VALUE_NONE
&& filter
< PNG_FILTER_VALUE_LAST
)
4141 if (pp
->read_filter
[0] == NULL
)
4142 png_init_filter_functions(pp
);
4144 pp
->read_filter
[filter
-1](row_info
, row
, prev_row
);
4148 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
4150 png_read_IDAT_data(png_structrp png_ptr
, png_bytep output
,
4151 png_alloc_size_t avail_out
)
4153 /* Loop reading IDATs and decompressing the result into output[avail_out] */
4154 png_ptr
->zstream
.next_out
= output
;
4155 png_ptr
->zstream
.avail_out
= 0; /* safety: set below */
4163 png_byte tmpbuf
[PNG_INFLATE_BUF_SIZE
];
4165 if (png_ptr
->zstream
.avail_in
== 0)
4170 while (png_ptr
->idat_size
== 0)
4172 png_crc_finish(png_ptr
, 0);
4174 png_ptr
->idat_size
= png_read_chunk_header(png_ptr
);
4175 /* This is an error even in the 'check' case because the code just
4176 * consumed a non-IDAT header.
4178 if (png_ptr
->chunk_name
!= png_IDAT
)
4179 png_error(png_ptr
, "Not enough image data");
4182 avail_in
= png_ptr
->IDAT_read_size
;
4184 if (avail_in
> png_ptr
->idat_size
)
4185 avail_in
= (uInt
)png_ptr
->idat_size
;
4187 /* A PNG with a gradually increasing IDAT size will defeat this attempt
4188 * to minimize memory usage by causing lots of re-allocs, but
4189 * realistically doing IDAT_read_size re-allocs is not likely to be a
4192 buffer
= png_read_buffer(png_ptr
, avail_in
, 0/*error*/);
4194 png_crc_read(png_ptr
, buffer
, avail_in
);
4195 png_ptr
->idat_size
-= avail_in
;
4197 png_ptr
->zstream
.next_in
= buffer
;
4198 png_ptr
->zstream
.avail_in
= avail_in
;
4201 /* And set up the output side. */
4202 if (output
!= NULL
) /* standard read */
4204 uInt out
= ZLIB_IO_MAX
;
4206 if (out
> avail_out
)
4207 out
= (uInt
)avail_out
;
4210 png_ptr
->zstream
.avail_out
= out
;
4213 else /* after last row, checking for end */
4215 png_ptr
->zstream
.next_out
= tmpbuf
;
4216 png_ptr
->zstream
.avail_out
= (sizeof tmpbuf
);
4219 /* Use NO_FLUSH; this gives zlib the maximum opportunity to optimize the
4220 * process. If the LZ stream is truncated the sequential reader will
4221 * terminally damage the stream, above, by reading the chunk header of the
4222 * following chunk (it then exits with png_error).
4224 * TODO: deal more elegantly with truncated IDAT lists.
4226 ret
= PNG_INFLATE(png_ptr
, Z_NO_FLUSH
);
4228 /* Take the unconsumed output back. */
4230 avail_out
+= png_ptr
->zstream
.avail_out
;
4232 else /* avail_out counts the extra bytes */
4233 avail_out
+= (sizeof tmpbuf
) - png_ptr
->zstream
.avail_out
;
4235 png_ptr
->zstream
.avail_out
= 0;
4237 if (ret
== Z_STREAM_END
)
4239 /* Do this for safety; we won't read any more into this row. */
4240 png_ptr
->zstream
.next_out
= NULL
;
4242 png_ptr
->mode
|= PNG_AFTER_IDAT
;
4243 png_ptr
->flags
|= PNG_FLAG_ZSTREAM_ENDED
;
4245 if (png_ptr
->zstream
.avail_in
> 0 || png_ptr
->idat_size
> 0)
4246 png_chunk_benign_error(png_ptr
, "Extra compressed data");
4252 png_zstream_error(png_ptr
, ret
);
4255 png_chunk_error(png_ptr
, png_ptr
->zstream
.msg
);
4259 png_chunk_benign_error(png_ptr
, png_ptr
->zstream
.msg
);
4263 } while (avail_out
> 0);
4267 /* The stream ended before the image; this is the same as too few IDATs so
4268 * should be handled the same way.
4271 png_error(png_ptr
, "Not enough image data");
4273 else /* the deflate stream contained extra data */
4274 png_chunk_benign_error(png_ptr
, "Too much image data");
4279 png_read_finish_IDAT(png_structrp png_ptr
)
4281 /* We don't need any more data and the stream should have ended, however the
4282 * LZ end code may actually not have been processed. In this case we must
4283 * read it otherwise stray unread IDAT data or, more likely, an IDAT chunk
4284 * may still remain to be consumed.
4286 if ((png_ptr
->flags
& PNG_FLAG_ZSTREAM_ENDED
) == 0)
4288 /* The NULL causes png_read_IDAT_data to swallow any remaining bytes in
4289 * the compressed stream, but the stream may be damaged too, so even after
4290 * this call we may need to terminate the zstream ownership.
4292 png_read_IDAT_data(png_ptr
, NULL
, 0);
4293 png_ptr
->zstream
.next_out
= NULL
; /* safety */
4295 /* Now clear everything out for safety; the following may not have been
4298 if ((png_ptr
->flags
& PNG_FLAG_ZSTREAM_ENDED
) == 0)
4300 png_ptr
->mode
|= PNG_AFTER_IDAT
;
4301 png_ptr
->flags
|= PNG_FLAG_ZSTREAM_ENDED
;
4305 /* If the zstream has not been released do it now *and* terminate the reading
4306 * of the final IDAT chunk.
4308 if (png_ptr
->zowner
== png_IDAT
)
4310 /* Always do this; the pointers otherwise point into the read buffer. */
4311 png_ptr
->zstream
.next_in
= NULL
;
4312 png_ptr
->zstream
.avail_in
= 0;
4314 /* Now we no longer own the zstream. */
4315 png_ptr
->zowner
= 0;
4317 /* The slightly weird semantics of the sequential IDAT reading is that we
4318 * are always in or at the end of an IDAT chunk, so we always need to do a
4319 * crc_finish here. If idat_size is non-zero we also need to read the
4320 * spurious bytes at the end of the chunk now.
4322 (void)png_crc_finish(png_ptr
, png_ptr
->idat_size
);
4327 png_read_finish_row(png_structrp png_ptr
)
4329 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
4331 /* Start of interlace block */
4332 static const png_byte png_pass_start
[7] = {0, 4, 0, 2, 0, 1, 0};
4334 /* Offset to next interlace block */
4335 static const png_byte png_pass_inc
[7] = {8, 8, 4, 4, 2, 2, 1};
4337 /* Start of interlace block in the y direction */
4338 static const png_byte png_pass_ystart
[7] = {0, 0, 4, 0, 2, 0, 1};
4340 /* Offset to next interlace block in the y direction */
4341 static const png_byte png_pass_yinc
[7] = {8, 8, 8, 4, 4, 2, 2};
4343 png_debug(1, "in png_read_finish_row");
4344 png_ptr
->row_number
++;
4345 if (png_ptr
->row_number
< png_ptr
->num_rows
)
4348 if (png_ptr
->interlaced
!= 0)
4350 png_ptr
->row_number
= 0;
4352 /* TO DO: don't do this if prev_row isn't needed (requires
4353 * read-ahead of the next row's filter byte.
4355 memset(png_ptr
->prev_row
, 0, png_ptr
->rowbytes
+ 1);
4361 if (png_ptr
->pass
>= 7)
4364 png_ptr
->iwidth
= (png_ptr
->width
+
4365 png_pass_inc
[png_ptr
->pass
] - 1 -
4366 png_pass_start
[png_ptr
->pass
]) /
4367 png_pass_inc
[png_ptr
->pass
];
4369 if ((png_ptr
->transformations
& PNG_INTERLACE
) == 0)
4371 png_ptr
->num_rows
= (png_ptr
->height
+
4372 png_pass_yinc
[png_ptr
->pass
] - 1 -
4373 png_pass_ystart
[png_ptr
->pass
]) /
4374 png_pass_yinc
[png_ptr
->pass
];
4377 else /* if (png_ptr->transformations & PNG_INTERLACE) */
4378 break; /* libpng deinterlacing sees every row */
4380 } while (png_ptr
->num_rows
== 0 || png_ptr
->iwidth
== 0);
4382 if (png_ptr
->pass
< 7)
4386 /* Here after at the end of the last row of the last pass. */
4387 png_read_finish_IDAT(png_ptr
);
4389 #endif /* SEQUENTIAL_READ */
4392 png_read_start_row(png_structrp png_ptr
)
4394 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
4396 /* Start of interlace block */
4397 static const png_byte png_pass_start
[7] = {0, 4, 0, 2, 0, 1, 0};
4399 /* Offset to next interlace block */
4400 static const png_byte png_pass_inc
[7] = {8, 8, 4, 4, 2, 2, 1};
4402 /* Start of interlace block in the y direction */
4403 static const png_byte png_pass_ystart
[7] = {0, 0, 4, 0, 2, 0, 1};
4405 /* Offset to next interlace block in the y direction */
4406 static const png_byte png_pass_yinc
[7] = {8, 8, 8, 4, 4, 2, 2};
4408 unsigned int max_pixel_depth
;
4411 png_debug(1, "in png_read_start_row");
4413 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
4414 png_init_read_transformations(png_ptr
);
4416 if (png_ptr
->interlaced
!= 0)
4418 if ((png_ptr
->transformations
& PNG_INTERLACE
) == 0)
4419 png_ptr
->num_rows
= (png_ptr
->height
+ png_pass_yinc
[0] - 1 -
4420 png_pass_ystart
[0]) / png_pass_yinc
[0];
4423 png_ptr
->num_rows
= png_ptr
->height
;
4425 png_ptr
->iwidth
= (png_ptr
->width
+
4426 png_pass_inc
[png_ptr
->pass
] - 1 -
4427 png_pass_start
[png_ptr
->pass
]) /
4428 png_pass_inc
[png_ptr
->pass
];
4433 png_ptr
->num_rows
= png_ptr
->height
;
4434 png_ptr
->iwidth
= png_ptr
->width
;
4437 max_pixel_depth
= (unsigned int)png_ptr
->pixel_depth
;
4439 /* WARNING: * png_read_transform_info (pngrtran.c) performs a simpler set of
4440 * calculations to calculate the final pixel depth, then
4441 * png_do_read_transforms actually does the transforms. This means that the
4442 * code which effectively calculates this value is actually repeated in three
4443 * separate places. They must all match. Innocent changes to the order of
4444 * transformations can and will break libpng in a way that causes memory
4449 #ifdef PNG_READ_PACK_SUPPORTED
4450 if ((png_ptr
->transformations
& PNG_PACK
) != 0 && png_ptr
->bit_depth
< 8)
4451 max_pixel_depth
= 8;
4454 #ifdef PNG_READ_EXPAND_SUPPORTED
4455 if ((png_ptr
->transformations
& PNG_EXPAND
) != 0)
4457 if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
4459 if (png_ptr
->num_trans
!= 0)
4460 max_pixel_depth
= 32;
4463 max_pixel_depth
= 24;
4466 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_GRAY
)
4468 if (max_pixel_depth
< 8)
4469 max_pixel_depth
= 8;
4471 if (png_ptr
->num_trans
!= 0)
4472 max_pixel_depth
*= 2;
4475 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_RGB
)
4477 if (png_ptr
->num_trans
!= 0)
4479 max_pixel_depth
*= 4;
4480 max_pixel_depth
/= 3;
4486 #ifdef PNG_READ_EXPAND_16_SUPPORTED
4487 if ((png_ptr
->transformations
& PNG_EXPAND_16
) != 0)
4489 # ifdef PNG_READ_EXPAND_SUPPORTED
4490 /* In fact it is an error if it isn't supported, but checking is
4493 if ((png_ptr
->transformations
& PNG_EXPAND
) != 0)
4495 if (png_ptr
->bit_depth
< 16)
4496 max_pixel_depth
*= 2;
4500 png_ptr
->transformations
&= ~PNG_EXPAND_16
;
4504 #ifdef PNG_READ_FILLER_SUPPORTED
4505 if ((png_ptr
->transformations
& (PNG_FILLER
)) != 0)
4507 if (png_ptr
->color_type
== PNG_COLOR_TYPE_GRAY
)
4509 if (max_pixel_depth
<= 8)
4510 max_pixel_depth
= 16;
4513 max_pixel_depth
= 32;
4516 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_RGB
||
4517 png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
4519 if (max_pixel_depth
<= 32)
4520 max_pixel_depth
= 32;
4523 max_pixel_depth
= 64;
4528 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
4529 if ((png_ptr
->transformations
& PNG_GRAY_TO_RGB
) != 0)
4532 #ifdef PNG_READ_EXPAND_SUPPORTED
4533 (png_ptr
->num_trans
!= 0 &&
4534 (png_ptr
->transformations
& PNG_EXPAND
) != 0) ||
4536 #ifdef PNG_READ_FILLER_SUPPORTED
4537 (png_ptr
->transformations
& (PNG_FILLER
)) != 0 ||
4539 png_ptr
->color_type
== PNG_COLOR_TYPE_GRAY_ALPHA
)
4541 if (max_pixel_depth
<= 16)
4542 max_pixel_depth
= 32;
4545 max_pixel_depth
= 64;
4550 if (max_pixel_depth
<= 8)
4552 if (png_ptr
->color_type
== PNG_COLOR_TYPE_RGB_ALPHA
)
4553 max_pixel_depth
= 32;
4556 max_pixel_depth
= 24;
4559 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_RGB_ALPHA
)
4560 max_pixel_depth
= 64;
4563 max_pixel_depth
= 48;
4568 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) && \
4569 defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
4570 if ((png_ptr
->transformations
& PNG_USER_TRANSFORM
) != 0)
4572 unsigned int user_pixel_depth
= png_ptr
->user_transform_depth
*
4573 png_ptr
->user_transform_channels
;
4575 if (user_pixel_depth
> max_pixel_depth
)
4576 max_pixel_depth
= user_pixel_depth
;
4580 /* This value is stored in png_struct and double checked in the row read
4583 png_ptr
->maximum_pixel_depth
= (png_byte
)max_pixel_depth
;
4584 png_ptr
->transformed_pixel_depth
= 0; /* calculated on demand */
4586 /* Align the width on the next larger 8 pixels. Mainly used
4589 row_bytes
= ((png_ptr
->width
+ 7) & ~((png_uint_32
)7));
4590 /* Calculate the maximum bytes needed, adding a byte and a pixel
4593 row_bytes
= PNG_ROWBYTES(max_pixel_depth
, row_bytes
) +
4594 1 + ((max_pixel_depth
+ 7) >> 3U);
4596 #ifdef PNG_MAX_MALLOC_64K
4597 if (row_bytes
> (png_uint_32
)65536L)
4598 png_error(png_ptr
, "This image requires a row greater than 64KB");
4601 if (row_bytes
+ 48 > png_ptr
->old_big_row_buf_size
)
4603 png_free(png_ptr
, png_ptr
->big_row_buf
);
4604 png_free(png_ptr
, png_ptr
->big_prev_row
);
4606 if (png_ptr
->interlaced
!= 0)
4607 png_ptr
->big_row_buf
= (png_bytep
)png_calloc(png_ptr
,
4611 png_ptr
->big_row_buf
= (png_bytep
)png_malloc(png_ptr
, row_bytes
+ 48);
4613 png_ptr
->big_prev_row
= (png_bytep
)png_malloc(png_ptr
, row_bytes
+ 48);
4615 #ifdef PNG_ALIGNED_MEMORY_SUPPORTED
4616 /* Use 16-byte aligned memory for row_buf with at least 16 bytes
4617 * of padding before and after row_buf; treat prev_row similarly.
4618 * NOTE: the alignment is to the start of the pixels, one beyond the start
4619 * of the buffer, because of the filter byte. Prior to libpng 1.5.6 this
4620 * was incorrect; the filter byte was aligned, which had the exact
4621 * opposite effect of that intended.
4624 png_bytep temp
= png_ptr
->big_row_buf
+ 32;
4625 size_t extra
= (size_t)temp
& 0x0f;
4626 png_ptr
->row_buf
= temp
- extra
- 1/*filter byte*/;
4628 temp
= png_ptr
->big_prev_row
+ 32;
4629 extra
= (size_t)temp
& 0x0f;
4630 png_ptr
->prev_row
= temp
- extra
- 1/*filter byte*/;
4633 /* Use 31 bytes of padding before and 17 bytes after row_buf. */
4634 png_ptr
->row_buf
= png_ptr
->big_row_buf
+ 31;
4635 png_ptr
->prev_row
= png_ptr
->big_prev_row
+ 31;
4637 png_ptr
->old_big_row_buf_size
= row_bytes
+ 48;
4640 #ifdef PNG_MAX_MALLOC_64K
4641 if (png_ptr
->rowbytes
> 65535)
4642 png_error(png_ptr
, "This image requires a row greater than 64KB");
4645 if (png_ptr
->rowbytes
> (PNG_SIZE_MAX
- 1))
4646 png_error(png_ptr
, "Row has too many bytes to allocate in memory");
4648 memset(png_ptr
->prev_row
, 0, png_ptr
->rowbytes
+ 1);
4650 png_debug1(3, "width = %u,", png_ptr
->width
);
4651 png_debug1(3, "height = %u,", png_ptr
->height
);
4652 png_debug1(3, "iwidth = %u,", png_ptr
->iwidth
);
4653 png_debug1(3, "num_rows = %u,", png_ptr
->num_rows
);
4654 png_debug1(3, "rowbytes = %lu,", (unsigned long)png_ptr
->rowbytes
);
4655 png_debug1(3, "irowbytes = %lu",
4656 (unsigned long)PNG_ROWBYTES(png_ptr
->pixel_depth
, png_ptr
->iwidth
) + 1);
4658 /* The sequential reader needs a buffer for IDAT, but the progressive reader
4659 * does not, so free the read buffer now regardless; the sequential reader
4660 * reallocates it on demand.
4662 if (png_ptr
->read_buffer
!= NULL
)
4664 png_bytep buffer
= png_ptr
->read_buffer
;
4666 png_ptr
->read_buffer_size
= 0;
4667 png_ptr
->read_buffer
= NULL
;
4668 png_free(png_ptr
, buffer
);
4671 /* Finally claim the zstream for the inflate of the IDAT data, use the bits
4672 * value from the stream (note that this will result in a fatal error if the
4673 * IDAT stream has a bogus deflate header window_bits value, but this should
4674 * not be happening any longer!)
4676 if (png_inflate_claim(png_ptr
, png_IDAT
) != Z_OK
)
4677 png_error(png_ptr
, png_ptr
->zstream
.msg
);
4679 png_ptr
->flags
|= PNG_FLAG_ROW_INIT
;