2 /* pngrutil.c - utilities to read a PNG file
4 * Last changed in libpng 1.6.8 [December 19, 2013]
5 * Copyright (c) 1998-2013 Glenn Randers-Pehrson
6 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
7 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
9 * This code is released under the libpng license.
10 * For conditions of distribution and use, see the disclaimer
11 * and license in png.h
13 * This file contains routines that are only called from within
14 * libpng itself during the course of reading an image.
19 #ifdef PNG_READ_SUPPORTED
22 png_get_uint_31(png_const_structrp png_ptr
, png_const_bytep buf
)
24 png_uint_32 uval
= png_get_uint_32(buf
);
26 if (uval
> PNG_UINT_31_MAX
)
27 png_error(png_ptr
, "PNG unsigned integer out of range");
32 #if defined(PNG_READ_gAMA_SUPPORTED) || defined(PNG_READ_cHRM_SUPPORTED)
33 /* The following is a variation on the above for use with the fixed
34 * point values used for gAMA and cHRM. Instead of png_error it
35 * issues a warning and returns (-1) - an invalid value because both
36 * gAMA and cHRM use *unsigned* integers for fixed point values.
38 #define PNG_FIXED_ERROR (-1)
40 static png_fixed_point
/* PRIVATE */
41 png_get_fixed_point(png_structrp png_ptr
, png_const_bytep buf
)
43 png_uint_32 uval
= png_get_uint_32(buf
);
45 if (uval
<= PNG_UINT_31_MAX
)
46 return (png_fixed_point
)uval
; /* known to be in range */
48 /* The caller can turn off the warning by passing NULL. */
50 png_warning(png_ptr
, "PNG fixed point integer out of range");
52 return PNG_FIXED_ERROR
;
56 #ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
57 /* NOTE: the read macros will obscure these definitions, so that if
58 * PNG_USE_READ_MACROS is set the library will not use them internally,
59 * but the APIs will still be available externally.
61 * The parentheses around "PNGAPI function_name" in the following three
62 * functions are necessary because they allow the macros to co-exist with
63 * these (unused but exported) functions.
66 /* Grab an unsigned 32-bit integer from a buffer in big-endian format. */
68 png_get_uint_32
)(png_const_bytep buf
)
71 ((png_uint_32
)(*(buf
)) << 24) +
72 ((png_uint_32
)(*(buf
+ 1)) << 16) +
73 ((png_uint_32
)(*(buf
+ 2)) << 8) +
74 ((png_uint_32
)(*(buf
+ 3)) ) ;
79 /* Grab a signed 32-bit integer from a buffer in big-endian format. The
80 * data is stored in the PNG file in two's complement format and there
81 * is no guarantee that a 'png_int_32' is exactly 32 bits, therefore
82 * the following code does a two's complement to native conversion.
85 png_get_int_32
)(png_const_bytep buf
)
87 png_uint_32 uval
= png_get_uint_32(buf
);
88 if ((uval
& 0x80000000) == 0) /* non-negative */
91 uval
= (uval
^ 0xffffffff) + 1; /* 2's complement: -x = ~x+1 */
92 return -(png_int_32
)uval
;
95 /* Grab an unsigned 16-bit integer from a buffer in big-endian format. */
97 png_get_uint_16
)(png_const_bytep buf
)
99 /* ANSI-C requires an int value to accomodate at least 16 bits so this
100 * works and allows the compiler not to worry about possible narrowing
101 * on 32 bit systems. (Pre-ANSI systems did not make integers smaller
102 * than 16 bits either.)
105 ((unsigned int)(*buf
) << 8) +
106 ((unsigned int)(*(buf
+ 1)));
108 return (png_uint_16
)val
;
111 #endif /* PNG_READ_INT_FUNCTIONS_SUPPORTED */
113 /* Read and check the PNG file signature */
115 png_read_sig(png_structrp png_ptr
, png_inforp info_ptr
)
117 png_size_t num_checked
, num_to_check
;
119 /* Exit if the user application does not expect a signature. */
120 if (png_ptr
->sig_bytes
>= 8)
123 num_checked
= png_ptr
->sig_bytes
;
124 num_to_check
= 8 - num_checked
;
126 #ifdef PNG_IO_STATE_SUPPORTED
127 png_ptr
->io_state
= PNG_IO_READING
| PNG_IO_SIGNATURE
;
130 /* The signature must be serialized in a single I/O call. */
131 png_read_data(png_ptr
, &(info_ptr
->signature
[num_checked
]), num_to_check
);
132 png_ptr
->sig_bytes
= 8;
134 if (png_sig_cmp(info_ptr
->signature
, num_checked
, num_to_check
))
136 if (num_checked
< 4 &&
137 png_sig_cmp(info_ptr
->signature
, num_checked
, num_to_check
- 4))
138 png_error(png_ptr
, "Not a PNG file");
140 png_error(png_ptr
, "PNG file corrupted by ASCII conversion");
143 png_ptr
->mode
|= PNG_HAVE_PNG_SIGNATURE
;
146 /* Read the chunk header (length + type name).
147 * Put the type name into png_ptr->chunk_name, and return the length.
149 png_uint_32
/* PRIVATE */
150 png_read_chunk_header(png_structrp png_ptr
)
155 #ifdef PNG_IO_STATE_SUPPORTED
156 png_ptr
->io_state
= PNG_IO_READING
| PNG_IO_CHUNK_HDR
;
159 /* Read the length and the chunk name.
160 * This must be performed in a single I/O call.
162 png_read_data(png_ptr
, buf
, 8);
163 length
= png_get_uint_31(png_ptr
, buf
);
165 /* Put the chunk name into png_ptr->chunk_name. */
166 png_ptr
->chunk_name
= PNG_CHUNK_FROM_STRING(buf
+4);
168 png_debug2(0, "Reading %lx chunk, length = %lu",
169 (unsigned long)png_ptr
->chunk_name
, (unsigned long)length
);
171 /* Reset the crc and run it over the chunk name. */
172 png_reset_crc(png_ptr
);
173 png_calculate_crc(png_ptr
, buf
+ 4, 4);
175 /* Check to see if chunk name is valid. */
176 png_check_chunk_name(png_ptr
, png_ptr
->chunk_name
);
178 #ifdef PNG_IO_STATE_SUPPORTED
179 png_ptr
->io_state
= PNG_IO_READING
| PNG_IO_CHUNK_DATA
;
185 /* Read data, and (optionally) run it through the CRC. */
187 png_crc_read(png_structrp png_ptr
, png_bytep buf
, png_uint_32 length
)
192 png_read_data(png_ptr
, buf
, length
);
193 png_calculate_crc(png_ptr
, buf
, length
);
196 /* Optionally skip data and then check the CRC. Depending on whether we
197 * are reading an ancillary or critical chunk, and how the program has set
198 * things up, we may calculate the CRC on the data and print a message.
199 * Returns '1' if there was a CRC error, '0' otherwise.
202 png_crc_finish(png_structrp png_ptr
, png_uint_32 skip
)
204 /* The size of the local buffer for inflate is a good guess as to a
205 * reasonable size to use for buffering reads from the application.
210 png_byte tmpbuf
[PNG_INFLATE_BUF_SIZE
];
212 len
= (sizeof tmpbuf
);
217 png_crc_read(png_ptr
, tmpbuf
, len
);
220 if (png_crc_error(png_ptr
))
222 if (PNG_CHUNK_ANCILLARY(png_ptr
->chunk_name
) ?
223 !(png_ptr
->flags
& PNG_FLAG_CRC_ANCILLARY_NOWARN
) :
224 (png_ptr
->flags
& PNG_FLAG_CRC_CRITICAL_USE
))
226 png_chunk_warning(png_ptr
, "CRC error");
231 png_chunk_benign_error(png_ptr
, "CRC error");
241 /* Compare the CRC stored in the PNG file with that calculated by libpng from
242 * the data it has read thus far.
245 png_crc_error(png_structrp png_ptr
)
247 png_byte crc_bytes
[4];
251 if (PNG_CHUNK_ANCILLARY(png_ptr
->chunk_name
))
253 if ((png_ptr
->flags
& PNG_FLAG_CRC_ANCILLARY_MASK
) ==
254 (PNG_FLAG_CRC_ANCILLARY_USE
| PNG_FLAG_CRC_ANCILLARY_NOWARN
))
260 if (png_ptr
->flags
& PNG_FLAG_CRC_CRITICAL_IGNORE
)
264 #ifdef PNG_IO_STATE_SUPPORTED
265 png_ptr
->io_state
= PNG_IO_READING
| PNG_IO_CHUNK_CRC
;
268 /* The chunk CRC must be serialized in a single I/O call. */
269 png_read_data(png_ptr
, crc_bytes
, 4);
273 crc
= png_get_uint_32(crc_bytes
);
274 return ((int)(crc
!= png_ptr
->crc
));
281 #if defined(PNG_READ_iCCP_SUPPORTED) || defined(PNG_READ_iTXt_SUPPORTED) ||\
282 defined(PNG_READ_pCAL_SUPPORTED) || defined(PNG_READ_sCAL_SUPPORTED) ||\
283 defined(PNG_READ_sPLT_SUPPORTED) || defined(PNG_READ_tEXt_SUPPORTED) ||\
284 defined(PNG_READ_zTXt_SUPPORTED) || defined(PNG_SEQUENTIAL_READ_SUPPORTED)
285 /* Manage the read buffer; this simply reallocates the buffer if it is not small
286 * enough (or if it is not allocated). The routine returns a pointer to the
287 * buffer; if an error occurs and 'warn' is set the routine returns NULL, else
288 * it will call png_error (via png_malloc) on failure. (warn == 2 means
292 png_read_buffer(png_structrp png_ptr
, png_alloc_size_t new_size
, int warn
)
294 png_bytep buffer
= png_ptr
->read_buffer
;
296 if (buffer
!= NULL
&& new_size
> png_ptr
->read_buffer_size
)
298 png_ptr
->read_buffer
= NULL
;
299 png_ptr
->read_buffer
= NULL
;
300 png_ptr
->read_buffer_size
= 0;
301 png_free(png_ptr
, buffer
);
307 buffer
= png_voidcast(png_bytep
, png_malloc_base(png_ptr
, new_size
));
311 png_ptr
->read_buffer
= buffer
;
312 png_ptr
->read_buffer_size
= new_size
;
315 else if (warn
< 2) /* else silent */
317 #ifdef PNG_WARNINGS_SUPPORTED
319 png_chunk_warning(png_ptr
, "insufficient memory to read chunk");
323 #ifdef PNG_ERROR_TEXT_SUPPORTED
324 png_chunk_error(png_ptr
, "insufficient memory to read chunk");
332 #endif /* PNG_READ_iCCP|iTXt|pCAL|sCAL|sPLT|tEXt|zTXt|SEQUENTIAL_READ */
334 /* png_inflate_claim: claim the zstream for some nefarious purpose that involves
335 * decompression. Returns Z_OK on success, else a zlib error code. It checks
336 * the owner but, in final release builds, just issues a warning if some other
337 * chunk apparently owns the stream. Prior to release it does a png_error.
340 png_inflate_claim(png_structrp png_ptr
, png_uint_32 owner
)
342 if (png_ptr
->zowner
!= 0)
346 PNG_STRING_FROM_CHUNK(msg
, png_ptr
->zowner
);
347 /* So the message that results is "<chunk> using zstream"; this is an
348 * internal error, but is very useful for debugging. i18n requirements
351 (void)png_safecat(msg
, (sizeof msg
), 4, " using zstream");
352 # if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
353 png_chunk_warning(png_ptr
, msg
);
356 png_chunk_error(png_ptr
, msg
);
360 /* Implementation note: unlike 'png_deflate_claim' this internal function
361 * does not take the size of the data as an argument. Some efficiency could
362 * be gained by using this when it is known *if* the zlib stream itself does
363 * not record the number; however, this is an illusion: the original writer
364 * of the PNG may have selected a lower window size, and we really must
365 * follow that because, for systems with with limited capabilities, we
366 * would otherwise reject the application's attempts to use a smaller window
367 * size (zlib doesn't have an interface to say "this or lower"!).
369 * inflateReset2 was added to zlib 1.2.4; before this the window could not be
370 * reset, therefore it is necessary to always allocate the maximum window
371 * size with earlier zlibs just in case later compressed chunks need it.
374 int ret
; /* zlib return code */
375 # if PNG_ZLIB_VERNUM >= 0x1240
377 # if defined(PNG_SET_OPTION_SUPPORTED) && \
378 defined(PNG_MAXIMUM_INFLATE_WINDOW)
381 if (((png_ptr
->options
>> PNG_MAXIMUM_INFLATE_WINDOW
) & 3) ==
388 # define window_bits 0
392 /* Set this for safety, just in case the previous owner left pointers to
393 * memory allocations.
395 png_ptr
->zstream
.next_in
= NULL
;
396 png_ptr
->zstream
.avail_in
= 0;
397 png_ptr
->zstream
.next_out
= NULL
;
398 png_ptr
->zstream
.avail_out
= 0;
400 if (png_ptr
->flags
& PNG_FLAG_ZSTREAM_INITIALIZED
)
402 # if PNG_ZLIB_VERNUM < 0x1240
403 ret
= inflateReset(&png_ptr
->zstream
);
405 ret
= inflateReset2(&png_ptr
->zstream
, window_bits
);
411 # if PNG_ZLIB_VERNUM < 0x1240
412 ret
= inflateInit(&png_ptr
->zstream
);
414 ret
= inflateInit2(&png_ptr
->zstream
, window_bits
);
418 png_ptr
->flags
|= PNG_FLAG_ZSTREAM_INITIALIZED
;
422 png_ptr
->zowner
= owner
;
425 png_zstream_error(png_ptr
, ret
);
435 #ifdef PNG_READ_COMPRESSED_TEXT_SUPPORTED
436 /* png_inflate now returns zlib error codes including Z_OK and Z_STREAM_END to
437 * allow the caller to do multiple calls if required. If the 'finish' flag is
438 * set Z_FINISH will be passed to the final inflate() call and Z_STREAM_END must
439 * be returned or there has been a problem, otherwise Z_SYNC_FLUSH is used and
440 * Z_OK or Z_STREAM_END will be returned on success.
442 * The input and output sizes are updated to the actual amounts of data consumed
443 * or written, not the amount available (as in a z_stream). The data pointers
444 * are not changed, so the next input is (data+input_size) and the next
445 * available output is (output+output_size).
448 png_inflate(png_structrp png_ptr
, png_uint_32 owner
, int finish
,
449 /* INPUT: */ png_const_bytep input
, png_uint_32p input_size_ptr
,
450 /* OUTPUT: */ png_bytep output
, png_alloc_size_t
*output_size_ptr
)
452 if (png_ptr
->zowner
== owner
) /* Else not claimed */
455 png_alloc_size_t avail_out
= *output_size_ptr
;
456 png_uint_32 avail_in
= *input_size_ptr
;
458 /* zlib can't necessarily handle more than 65535 bytes at once (i.e. it
459 * can't even necessarily handle 65536 bytes) because the type uInt is
460 * "16 bits or more". Consequently it is necessary to chunk the input to
461 * zlib. This code uses ZLIB_IO_MAX, from pngpriv.h, as the maximum (the
462 * maximum value that can be stored in a uInt.) It is possible to set
463 * ZLIB_IO_MAX to a lower value in pngpriv.h and this may sometimes have
464 * a performance advantage, because it reduces the amount of data accessed
465 * at each step and that may give the OS more time to page it in.
467 png_ptr
->zstream
.next_in
= PNGZ_INPUT_CAST(input
);
468 /* avail_in and avail_out are set below from 'size' */
469 png_ptr
->zstream
.avail_in
= 0;
470 png_ptr
->zstream
.avail_out
= 0;
472 /* Read directly into the output if it is available (this is set to
473 * a local buffer below if output is NULL).
476 png_ptr
->zstream
.next_out
= output
;
481 Byte local_buffer
[PNG_INFLATE_BUF_SIZE
];
483 /* zlib INPUT BUFFER */
484 /* The setting of 'avail_in' used to be outside the loop; by setting it
485 * inside it is possible to chunk the input to zlib and simply rely on
486 * zlib to advance the 'next_in' pointer. This allows arbitrary
487 * amounts of data to be passed through zlib at the unavoidable cost of
488 * requiring a window save (memcpy of up to 32768 output bytes)
489 * every ZLIB_IO_MAX input bytes.
491 avail_in
+= png_ptr
->zstream
.avail_in
; /* not consumed last time */
495 if (avail_in
< avail
)
496 avail
= (uInt
)avail_in
; /* safe: < than ZLIB_IO_MAX */
499 png_ptr
->zstream
.avail_in
= avail
;
501 /* zlib OUTPUT BUFFER */
502 avail_out
+= png_ptr
->zstream
.avail_out
; /* not written last time */
504 avail
= ZLIB_IO_MAX
; /* maximum zlib can process */
508 /* Reset the output buffer each time round if output is NULL and
509 * make available the full buffer, up to 'remaining_space'
511 png_ptr
->zstream
.next_out
= local_buffer
;
512 if ((sizeof local_buffer
) < avail
)
513 avail
= (sizeof local_buffer
);
516 if (avail_out
< avail
)
517 avail
= (uInt
)avail_out
; /* safe: < ZLIB_IO_MAX */
519 png_ptr
->zstream
.avail_out
= avail
;
522 /* zlib inflate call */
523 /* In fact 'avail_out' may be 0 at this point, that happens at the end
524 * of the read when the final LZ end code was not passed at the end of
525 * the previous chunk of input data. Tell zlib if we have reached the
526 * end of the output buffer.
528 ret
= inflate(&png_ptr
->zstream
, avail_out
> 0 ? Z_NO_FLUSH
:
529 (finish ? Z_FINISH
: Z_SYNC_FLUSH
));
530 } while (ret
== Z_OK
);
532 /* For safety kill the local buffer pointer now */
534 png_ptr
->zstream
.next_out
= NULL
;
536 /* Claw back the 'size' and 'remaining_space' byte counts. */
537 avail_in
+= png_ptr
->zstream
.avail_in
;
538 avail_out
+= png_ptr
->zstream
.avail_out
;
540 /* Update the input and output sizes; the updated values are the amount
541 * consumed or written, effectively the inverse of what zlib uses.
544 *output_size_ptr
-= avail_out
;
547 *input_size_ptr
-= avail_in
;
549 /* Ensure png_ptr->zstream.msg is set (even in the success case!) */
550 png_zstream_error(png_ptr
, ret
);
556 /* This is a bad internal error. The recovery assigns to the zstream msg
557 * pointer, which is not owned by the caller, but this is safe; it's only
560 png_ptr
->zstream
.msg
= PNGZ_MSG_CAST("zstream unclaimed");
561 return Z_STREAM_ERROR
;
566 * Decompress trailing data in a chunk. The assumption is that read_buffer
567 * points at an allocated area holding the contents of a chunk with a
568 * trailing compressed part. What we get back is an allocated area
569 * holding the original prefix part and an uncompressed version of the
570 * trailing part (the malloc area passed in is freed).
573 png_decompress_chunk(png_structrp png_ptr
,
574 png_uint_32 chunklength
, png_uint_32 prefix_size
,
575 png_alloc_size_t
*newlength
/* must be initialized to the maximum! */,
576 int terminate
/*add a '\0' to the end of the uncompressed data*/)
578 /* TODO: implement different limits for different types of chunk.
580 * The caller supplies *newlength set to the maximum length of the
581 * uncompressed data, but this routine allocates space for the prefix and
582 * maybe a '\0' terminator too. We have to assume that 'prefix_size' is
583 * limited only by the maximum chunk size.
585 png_alloc_size_t limit
= PNG_SIZE_MAX
;
587 # ifdef PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED
588 if (png_ptr
->user_chunk_malloc_max
> 0 &&
589 png_ptr
->user_chunk_malloc_max
< limit
)
590 limit
= png_ptr
->user_chunk_malloc_max
;
591 # elif PNG_USER_CHUNK_MALLOC_MAX > 0
592 if (PNG_USER_CHUNK_MALLOC_MAX
< limit
)
593 limit
= PNG_USER_CHUNK_MALLOC_MAX
;
596 if (limit
>= prefix_size
+ (terminate
!= 0))
600 limit
-= prefix_size
+ (terminate
!= 0);
602 if (limit
< *newlength
)
605 /* Now try to claim the stream. */
606 ret
= png_inflate_claim(png_ptr
, png_ptr
->chunk_name
);
610 png_uint_32 lzsize
= chunklength
- prefix_size
;
612 ret
= png_inflate(png_ptr
, png_ptr
->chunk_name
, 1/*finish*/,
613 /* input: */ png_ptr
->read_buffer
+ prefix_size
, &lzsize
,
614 /* output: */ NULL
, newlength
);
616 if (ret
== Z_STREAM_END
)
618 /* Use 'inflateReset' here, not 'inflateReset2' because this
619 * preserves the previously decided window size (otherwise it would
620 * be necessary to store the previous window size.) In practice
621 * this doesn't matter anyway, because png_inflate will call inflate
622 * with Z_FINISH in almost all cases, so the window will not be
625 if (inflateReset(&png_ptr
->zstream
) == Z_OK
)
627 /* Because of the limit checks above we know that the new,
628 * expanded, size will fit in a size_t (let alone an
629 * png_alloc_size_t). Use png_malloc_base here to avoid an
632 png_alloc_size_t new_size
= *newlength
;
633 png_alloc_size_t buffer_size
= prefix_size
+ new_size
+
635 png_bytep text
= png_voidcast(png_bytep
, png_malloc_base(png_ptr
,
640 ret
= png_inflate(png_ptr
, png_ptr
->chunk_name
, 1/*finish*/,
641 png_ptr
->read_buffer
+ prefix_size
, &lzsize
,
642 text
+ prefix_size
, newlength
);
644 if (ret
== Z_STREAM_END
)
646 if (new_size
== *newlength
)
649 text
[prefix_size
+ *newlength
] = 0;
652 memcpy(text
, png_ptr
->read_buffer
, prefix_size
);
655 png_bytep old_ptr
= png_ptr
->read_buffer
;
657 png_ptr
->read_buffer
= text
;
658 png_ptr
->read_buffer_size
= buffer_size
;
659 text
= old_ptr
; /* freed below */
665 /* The size changed on the second read, there can be no
666 * guarantee that anything is correct at this point.
667 * The 'msg' pointer has been set to "unexpected end of
668 * LZ stream", which is fine, but return an error code
669 * that the caller won't accept.
671 ret
= PNG_UNEXPECTED_ZLIB_RETURN
;
675 else if (ret
== Z_OK
)
676 ret
= PNG_UNEXPECTED_ZLIB_RETURN
; /* for safety */
678 /* Free the text pointer (this is the old read_buffer on
681 png_free(png_ptr
, text
);
683 /* This really is very benign, but it's still an error because
684 * the extra space may otherwise be used as a Trojan Horse.
686 if (ret
== Z_STREAM_END
&&
687 chunklength
- prefix_size
!= lzsize
)
688 png_chunk_benign_error(png_ptr
, "extra compressed data");
693 /* Out of memory allocating the buffer */
695 png_zstream_error(png_ptr
, Z_MEM_ERROR
);
701 /* inflateReset failed, store the error message */
702 png_zstream_error(png_ptr
, ret
);
704 if (ret
== Z_STREAM_END
)
705 ret
= PNG_UNEXPECTED_ZLIB_RETURN
;
709 else if (ret
== Z_OK
)
710 ret
= PNG_UNEXPECTED_ZLIB_RETURN
;
712 /* Release the claimed stream */
716 else /* the claim failed */ if (ret
== Z_STREAM_END
) /* impossible! */
717 ret
= PNG_UNEXPECTED_ZLIB_RETURN
;
724 /* Application/configuration limits exceeded */
725 png_zstream_error(png_ptr
, Z_MEM_ERROR
);
729 #endif /* PNG_READ_COMPRESSED_TEXT_SUPPORTED */
731 #ifdef PNG_READ_iCCP_SUPPORTED
732 /* Perform a partial read and decompress, producing 'avail_out' bytes and
733 * reading from the current chunk as required.
736 png_inflate_read(png_structrp png_ptr
, png_bytep read_buffer
, uInt read_size
,
737 png_uint_32p chunk_bytes
, png_bytep next_out
, png_alloc_size_t
*out_size
,
740 if (png_ptr
->zowner
== png_ptr
->chunk_name
)
744 /* next_in and avail_in must have been initialized by the caller. */
745 png_ptr
->zstream
.next_out
= next_out
;
746 png_ptr
->zstream
.avail_out
= 0; /* set in the loop */
750 if (png_ptr
->zstream
.avail_in
== 0)
752 if (read_size
> *chunk_bytes
)
753 read_size
= (uInt
)*chunk_bytes
;
754 *chunk_bytes
-= read_size
;
757 png_crc_read(png_ptr
, read_buffer
, read_size
);
759 png_ptr
->zstream
.next_in
= read_buffer
;
760 png_ptr
->zstream
.avail_in
= read_size
;
763 if (png_ptr
->zstream
.avail_out
== 0)
765 uInt avail
= ZLIB_IO_MAX
;
766 if (avail
> *out_size
)
767 avail
= (uInt
)*out_size
;
770 png_ptr
->zstream
.avail_out
= avail
;
773 /* Use Z_SYNC_FLUSH when there is no more chunk data to ensure that all
774 * the available output is produced; this allows reading of truncated
777 ret
= inflate(&png_ptr
->zstream
,
778 *chunk_bytes
> 0 ? Z_NO_FLUSH
: (finish ? Z_FINISH
: Z_SYNC_FLUSH
));
780 while (ret
== Z_OK
&& (*out_size
> 0 || png_ptr
->zstream
.avail_out
> 0));
782 *out_size
+= png_ptr
->zstream
.avail_out
;
783 png_ptr
->zstream
.avail_out
= 0; /* Should not be required, but is safe */
785 /* Ensure the error message pointer is always set: */
786 png_zstream_error(png_ptr
, ret
);
792 png_ptr
->zstream
.msg
= PNGZ_MSG_CAST("zstream unclaimed");
793 return Z_STREAM_ERROR
;
798 /* Read and check the IDHR chunk */
800 png_handle_IHDR(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
803 png_uint_32 width
, height
;
804 int bit_depth
, color_type
, compression_type
, filter_type
;
807 png_debug(1, "in png_handle_IHDR");
809 if (png_ptr
->mode
& PNG_HAVE_IHDR
)
810 png_chunk_error(png_ptr
, "out of place");
812 /* Check the length */
814 png_chunk_error(png_ptr
, "invalid");
816 png_ptr
->mode
|= PNG_HAVE_IHDR
;
818 png_crc_read(png_ptr
, buf
, 13);
819 png_crc_finish(png_ptr
, 0);
821 width
= png_get_uint_31(png_ptr
, buf
);
822 height
= png_get_uint_31(png_ptr
, buf
+ 4);
825 compression_type
= buf
[10];
826 filter_type
= buf
[11];
827 interlace_type
= buf
[12];
829 /* Set internal variables */
830 png_ptr
->width
= width
;
831 png_ptr
->height
= height
;
832 png_ptr
->bit_depth
= (png_byte
)bit_depth
;
833 png_ptr
->interlaced
= (png_byte
)interlace_type
;
834 png_ptr
->color_type
= (png_byte
)color_type
;
835 #ifdef PNG_MNG_FEATURES_SUPPORTED
836 png_ptr
->filter_type
= (png_byte
)filter_type
;
838 png_ptr
->compression_type
= (png_byte
)compression_type
;
840 /* Find number of channels */
841 switch (png_ptr
->color_type
)
843 default: /* invalid, png_set_IHDR calls png_error */
844 case PNG_COLOR_TYPE_GRAY
:
845 case PNG_COLOR_TYPE_PALETTE
:
846 png_ptr
->channels
= 1;
849 case PNG_COLOR_TYPE_RGB
:
850 png_ptr
->channels
= 3;
853 case PNG_COLOR_TYPE_GRAY_ALPHA
:
854 png_ptr
->channels
= 2;
857 case PNG_COLOR_TYPE_RGB_ALPHA
:
858 png_ptr
->channels
= 4;
862 /* Set up other useful info */
863 png_ptr
->pixel_depth
= (png_byte
)(png_ptr
->bit_depth
*
865 png_ptr
->rowbytes
= PNG_ROWBYTES(png_ptr
->pixel_depth
, png_ptr
->width
);
866 png_debug1(3, "bit_depth = %d", png_ptr
->bit_depth
);
867 png_debug1(3, "channels = %d", png_ptr
->channels
);
868 png_debug1(3, "rowbytes = %lu", (unsigned long)png_ptr
->rowbytes
);
869 png_set_IHDR(png_ptr
, info_ptr
, width
, height
, bit_depth
,
870 color_type
, interlace_type
, compression_type
, filter_type
);
873 /* Read and check the palette */
875 png_handle_PLTE(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
877 png_color palette
[PNG_MAX_PALETTE_LENGTH
];
879 #ifdef PNG_POINTER_INDEXING_SUPPORTED
883 png_debug(1, "in png_handle_PLTE");
885 if (!(png_ptr
->mode
& PNG_HAVE_IHDR
))
886 png_chunk_error(png_ptr
, "missing IHDR");
888 /* Moved to before the 'after IDAT' check below because otherwise duplicate
889 * PLTE chunks are potentially ignored (the spec says there shall not be more
890 * than one PLTE, the error is not treated as benign, so this check trumps
891 * the requirement that PLTE appears before IDAT.)
893 else if (png_ptr
->mode
& PNG_HAVE_PLTE
)
894 png_chunk_error(png_ptr
, "duplicate");
896 else if (png_ptr
->mode
& PNG_HAVE_IDAT
)
898 /* This is benign because the non-benign error happened before, when an
899 * IDAT was encountered in a color-mapped image with no PLTE.
901 png_crc_finish(png_ptr
, length
);
902 png_chunk_benign_error(png_ptr
, "out of place");
906 png_ptr
->mode
|= PNG_HAVE_PLTE
;
908 if (!(png_ptr
->color_type
& PNG_COLOR_MASK_COLOR
))
910 png_crc_finish(png_ptr
, length
);
911 png_chunk_benign_error(png_ptr
, "ignored in grayscale PNG");
915 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
916 if (png_ptr
->color_type
!= PNG_COLOR_TYPE_PALETTE
)
918 png_crc_finish(png_ptr
, length
);
923 if (length
> 3*PNG_MAX_PALETTE_LENGTH
|| length
% 3)
925 png_crc_finish(png_ptr
, length
);
927 if (png_ptr
->color_type
!= PNG_COLOR_TYPE_PALETTE
)
928 png_chunk_benign_error(png_ptr
, "invalid");
931 png_chunk_error(png_ptr
, "invalid");
936 /* The cast is safe because 'length' is less than 3*PNG_MAX_PALETTE_LENGTH */
937 num
= (int)length
/ 3;
939 #ifdef PNG_POINTER_INDEXING_SUPPORTED
940 for (i
= 0, pal_ptr
= palette
; i
< num
; i
++, pal_ptr
++)
944 png_crc_read(png_ptr
, buf
, 3);
945 pal_ptr
->red
= buf
[0];
946 pal_ptr
->green
= buf
[1];
947 pal_ptr
->blue
= buf
[2];
950 for (i
= 0; i
< num
; i
++)
954 png_crc_read(png_ptr
, buf
, 3);
955 /* Don't depend upon png_color being any order */
956 palette
[i
].red
= buf
[0];
957 palette
[i
].green
= buf
[1];
958 palette
[i
].blue
= buf
[2];
962 /* If we actually need the PLTE chunk (ie for a paletted image), we do
963 * whatever the normal CRC configuration tells us. However, if we
964 * have an RGB image, the PLTE can be considered ancillary, so
965 * we will act as though it is.
967 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
968 if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
971 png_crc_finish(png_ptr
, 0);
974 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
975 else if (png_crc_error(png_ptr
)) /* Only if we have a CRC error */
977 /* If we don't want to use the data from an ancillary chunk,
978 * we have two options: an error abort, or a warning and we
979 * ignore the data in this chunk (which should be OK, since
980 * it's considered ancillary for a RGB or RGBA image).
982 * IMPLEMENTATION NOTE: this is only here because png_crc_finish uses the
983 * chunk type to determine whether to check the ancillary or the critical
986 if (!(png_ptr
->flags
& PNG_FLAG_CRC_ANCILLARY_USE
))
988 if (png_ptr
->flags
& PNG_FLAG_CRC_ANCILLARY_NOWARN
)
990 png_chunk_benign_error(png_ptr
, "CRC error");
995 png_chunk_warning(png_ptr
, "CRC error");
1000 /* Otherwise, we (optionally) emit a warning and use the chunk. */
1001 else if (!(png_ptr
->flags
& PNG_FLAG_CRC_ANCILLARY_NOWARN
))
1003 png_chunk_warning(png_ptr
, "CRC error");
1008 /* TODO: png_set_PLTE has the side effect of setting png_ptr->palette to its
1009 * own copy of the palette. This has the side effect that when png_start_row
1010 * is called (this happens after any call to png_read_update_info) the
1011 * info_ptr palette gets changed. This is extremely unexpected and
1014 * Fix this by not sharing the palette in this way.
1016 png_set_PLTE(png_ptr
, info_ptr
, palette
, num
);
1018 /* The three chunks, bKGD, hIST and tRNS *must* appear after PLTE and before
1019 * IDAT. Prior to 1.6.0 this was not checked; instead the code merely
1020 * checked the apparent validity of a tRNS chunk inserted before PLTE on a
1021 * palette PNG. 1.6.0 attempts to rigorously follow the standard and
1022 * therefore does a benign error if the erroneous condition is detected *and*
1023 * cancels the tRNS if the benign error returns. The alternative is to
1024 * amend the standard since it would be rather hypocritical of the standards
1025 * maintainers to ignore it.
1027 #ifdef PNG_READ_tRNS_SUPPORTED
1028 if (png_ptr
->num_trans
> 0 ||
1029 (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_tRNS
) != 0))
1031 /* Cancel this because otherwise it would be used if the transforms
1032 * require it. Don't cancel the 'valid' flag because this would prevent
1033 * detection of duplicate chunks.
1035 png_ptr
->num_trans
= 0;
1037 if (info_ptr
!= NULL
)
1038 info_ptr
->num_trans
= 0;
1040 png_chunk_benign_error(png_ptr
, "tRNS must be after");
1044 #ifdef PNG_READ_hIST_SUPPORTED
1045 if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_hIST
) != 0)
1046 png_chunk_benign_error(png_ptr
, "hIST must be after");
1049 #ifdef PNG_READ_bKGD_SUPPORTED
1050 if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_bKGD
) != 0)
1051 png_chunk_benign_error(png_ptr
, "bKGD must be after");
1056 png_handle_IEND(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1058 png_debug(1, "in png_handle_IEND");
1060 if (!(png_ptr
->mode
& PNG_HAVE_IHDR
) || !(png_ptr
->mode
& PNG_HAVE_IDAT
))
1061 png_chunk_error(png_ptr
, "out of place");
1063 png_ptr
->mode
|= (PNG_AFTER_IDAT
| PNG_HAVE_IEND
);
1065 png_crc_finish(png_ptr
, length
);
1068 png_chunk_benign_error(png_ptr
, "invalid");
1070 PNG_UNUSED(info_ptr
)
1073 #ifdef PNG_READ_gAMA_SUPPORTED
1075 png_handle_gAMA(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1077 png_fixed_point igamma
;
1080 png_debug(1, "in png_handle_gAMA");
1082 if (!(png_ptr
->mode
& PNG_HAVE_IHDR
))
1083 png_chunk_error(png_ptr
, "missing IHDR");
1085 else if (png_ptr
->mode
& (PNG_HAVE_IDAT
|PNG_HAVE_PLTE
))
1087 png_crc_finish(png_ptr
, length
);
1088 png_chunk_benign_error(png_ptr
, "out of place");
1094 png_crc_finish(png_ptr
, length
);
1095 png_chunk_benign_error(png_ptr
, "invalid");
1099 png_crc_read(png_ptr
, buf
, 4);
1101 if (png_crc_finish(png_ptr
, 0))
1104 igamma
= png_get_fixed_point(NULL
, buf
);
1106 png_colorspace_set_gamma(png_ptr
, &png_ptr
->colorspace
, igamma
);
1107 png_colorspace_sync(png_ptr
, info_ptr
);
1111 #ifdef PNG_READ_sBIT_SUPPORTED
1113 png_handle_sBIT(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1115 unsigned int truelen
;
1118 png_debug(1, "in png_handle_sBIT");
1120 buf
[0] = buf
[1] = buf
[2] = buf
[3] = 0;
1122 if (!(png_ptr
->mode
& PNG_HAVE_IHDR
))
1123 png_chunk_error(png_ptr
, "missing IHDR");
1125 else if (png_ptr
->mode
& (PNG_HAVE_IDAT
|PNG_HAVE_PLTE
))
1127 png_crc_finish(png_ptr
, length
);
1128 png_chunk_benign_error(png_ptr
, "out of place");
1132 if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_sBIT
))
1134 png_crc_finish(png_ptr
, length
);
1135 png_chunk_benign_error(png_ptr
, "duplicate");
1139 if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
1143 truelen
= png_ptr
->channels
;
1145 if (length
!= truelen
|| length
> 4)
1147 png_chunk_benign_error(png_ptr
, "invalid");
1148 png_crc_finish(png_ptr
, length
);
1152 png_crc_read(png_ptr
, buf
, truelen
);
1154 if (png_crc_finish(png_ptr
, 0))
1157 if (png_ptr
->color_type
& PNG_COLOR_MASK_COLOR
)
1159 png_ptr
->sig_bit
.red
= buf
[0];
1160 png_ptr
->sig_bit
.green
= buf
[1];
1161 png_ptr
->sig_bit
.blue
= buf
[2];
1162 png_ptr
->sig_bit
.alpha
= buf
[3];
1167 png_ptr
->sig_bit
.gray
= buf
[0];
1168 png_ptr
->sig_bit
.red
= buf
[0];
1169 png_ptr
->sig_bit
.green
= buf
[0];
1170 png_ptr
->sig_bit
.blue
= buf
[0];
1171 png_ptr
->sig_bit
.alpha
= buf
[1];
1174 png_set_sBIT(png_ptr
, info_ptr
, &(png_ptr
->sig_bit
));
1178 #ifdef PNG_READ_cHRM_SUPPORTED
1180 png_handle_cHRM(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1185 png_debug(1, "in png_handle_cHRM");
1187 if (!(png_ptr
->mode
& PNG_HAVE_IHDR
))
1188 png_chunk_error(png_ptr
, "missing IHDR");
1190 else if (png_ptr
->mode
& (PNG_HAVE_IDAT
|PNG_HAVE_PLTE
))
1192 png_crc_finish(png_ptr
, length
);
1193 png_chunk_benign_error(png_ptr
, "out of place");
1199 png_crc_finish(png_ptr
, length
);
1200 png_chunk_benign_error(png_ptr
, "invalid");
1204 png_crc_read(png_ptr
, buf
, 32);
1206 if (png_crc_finish(png_ptr
, 0))
1209 xy
.whitex
= png_get_fixed_point(NULL
, buf
);
1210 xy
.whitey
= png_get_fixed_point(NULL
, buf
+ 4);
1211 xy
.redx
= png_get_fixed_point(NULL
, buf
+ 8);
1212 xy
.redy
= png_get_fixed_point(NULL
, buf
+ 12);
1213 xy
.greenx
= png_get_fixed_point(NULL
, buf
+ 16);
1214 xy
.greeny
= png_get_fixed_point(NULL
, buf
+ 20);
1215 xy
.bluex
= png_get_fixed_point(NULL
, buf
+ 24);
1216 xy
.bluey
= png_get_fixed_point(NULL
, buf
+ 28);
1218 if (xy
.whitex
== PNG_FIXED_ERROR
||
1219 xy
.whitey
== PNG_FIXED_ERROR
||
1220 xy
.redx
== PNG_FIXED_ERROR
||
1221 xy
.redy
== PNG_FIXED_ERROR
||
1222 xy
.greenx
== PNG_FIXED_ERROR
||
1223 xy
.greeny
== PNG_FIXED_ERROR
||
1224 xy
.bluex
== PNG_FIXED_ERROR
||
1225 xy
.bluey
== PNG_FIXED_ERROR
)
1227 png_chunk_benign_error(png_ptr
, "invalid values");
1231 /* If a colorspace error has already been output skip this chunk */
1232 if (png_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
)
1235 if (png_ptr
->colorspace
.flags
& PNG_COLORSPACE_FROM_cHRM
)
1237 png_ptr
->colorspace
.flags
|= PNG_COLORSPACE_INVALID
;
1238 png_colorspace_sync(png_ptr
, info_ptr
);
1239 png_chunk_benign_error(png_ptr
, "duplicate");
1243 png_ptr
->colorspace
.flags
|= PNG_COLORSPACE_FROM_cHRM
;
1244 (void)png_colorspace_set_chromaticities(png_ptr
, &png_ptr
->colorspace
, &xy
,
1245 1/*prefer cHRM values*/);
1246 png_colorspace_sync(png_ptr
, info_ptr
);
1250 #ifdef PNG_READ_sRGB_SUPPORTED
1252 png_handle_sRGB(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1256 png_debug(1, "in png_handle_sRGB");
1258 if (!(png_ptr
->mode
& PNG_HAVE_IHDR
))
1259 png_chunk_error(png_ptr
, "missing IHDR");
1261 else if (png_ptr
->mode
& (PNG_HAVE_IDAT
|PNG_HAVE_PLTE
))
1263 png_crc_finish(png_ptr
, length
);
1264 png_chunk_benign_error(png_ptr
, "out of place");
1270 png_crc_finish(png_ptr
, length
);
1271 png_chunk_benign_error(png_ptr
, "invalid");
1275 png_crc_read(png_ptr
, &intent
, 1);
1277 if (png_crc_finish(png_ptr
, 0))
1280 /* If a colorspace error has already been output skip this chunk */
1281 if (png_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
)
1284 /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
1287 if (png_ptr
->colorspace
.flags
& PNG_COLORSPACE_HAVE_INTENT
)
1289 png_ptr
->colorspace
.flags
|= PNG_COLORSPACE_INVALID
;
1290 png_colorspace_sync(png_ptr
, info_ptr
);
1291 png_chunk_benign_error(png_ptr
, "too many profiles");
1295 (void)png_colorspace_set_sRGB(png_ptr
, &png_ptr
->colorspace
, intent
);
1296 png_colorspace_sync(png_ptr
, info_ptr
);
1298 #endif /* PNG_READ_sRGB_SUPPORTED */
1300 #ifdef PNG_READ_iCCP_SUPPORTED
1302 png_handle_iCCP(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1303 /* Note: this does not properly handle profiles that are > 64K under DOS */
1305 png_const_charp errmsg
= NULL
; /* error message output, or no error */
1306 int finished
= 0; /* crc checked */
1308 png_debug(1, "in png_handle_iCCP");
1310 if (!(png_ptr
->mode
& PNG_HAVE_IHDR
))
1311 png_chunk_error(png_ptr
, "missing IHDR");
1313 else if (png_ptr
->mode
& (PNG_HAVE_IDAT
|PNG_HAVE_PLTE
))
1315 png_crc_finish(png_ptr
, length
);
1316 png_chunk_benign_error(png_ptr
, "out of place");
1320 /* Consistent with all the above colorspace handling an obviously *invalid*
1321 * chunk is just ignored, so does not invalidate the color space. An
1322 * alternative is to set the 'invalid' flags at the start of this routine
1323 * and only clear them in they were not set before and all the tests pass.
1324 * The minimum 'deflate' stream is assumed to be just the 2 byte header and 4
1325 * byte checksum. The keyword must be one character and there is a
1326 * terminator (0) byte and the compression method.
1330 png_crc_finish(png_ptr
, length
);
1331 png_chunk_benign_error(png_ptr
, "too short");
1335 /* If a colorspace error has already been output skip this chunk */
1336 if (png_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
)
1338 png_crc_finish(png_ptr
, length
);
1342 /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
1345 if ((png_ptr
->colorspace
.flags
& PNG_COLORSPACE_HAVE_INTENT
) == 0)
1347 uInt read_length
, keyword_length
;
1350 /* Find the keyword; the keyword plus separator and compression method
1351 * bytes can be at most 81 characters long.
1353 read_length
= 81; /* maximum */
1354 if (read_length
> length
)
1355 read_length
= (uInt
)length
;
1357 png_crc_read(png_ptr
, (png_bytep
)keyword
, read_length
);
1358 length
-= read_length
;
1361 while (keyword_length
< 80 && keyword_length
< read_length
&&
1362 keyword
[keyword_length
] != 0)
1365 /* TODO: make the keyword checking common */
1366 if (keyword_length
>= 1 && keyword_length
<= 79)
1368 /* We only understand '0' compression - deflate - so if we get a
1369 * different value we can't safely decode the chunk.
1371 if (keyword_length
+1 < read_length
&&
1372 keyword
[keyword_length
+1] == PNG_COMPRESSION_TYPE_BASE
)
1374 read_length
-= keyword_length
+2;
1376 if (png_inflate_claim(png_ptr
, png_iCCP
) == Z_OK
)
1378 Byte profile_header
[132];
1379 Byte local_buffer
[PNG_INFLATE_BUF_SIZE
];
1380 png_alloc_size_t size
= (sizeof profile_header
);
1382 png_ptr
->zstream
.next_in
= (Bytef
*)keyword
+ (keyword_length
+2);
1383 png_ptr
->zstream
.avail_in
= read_length
;
1384 (void)png_inflate_read(png_ptr
, local_buffer
,
1385 (sizeof local_buffer
), &length
, profile_header
, &size
,
1386 0/*finish: don't, because the output is too small*/);
1390 /* We have the ICC profile header; do the basic header checks.
1392 const png_uint_32 profile_length
=
1393 png_get_uint_32(profile_header
);
1395 if (png_icc_check_length(png_ptr
, &png_ptr
->colorspace
,
1396 keyword
, profile_length
))
1398 /* The length is apparently ok, so we can check the 132
1401 if (png_icc_check_header(png_ptr
, &png_ptr
->colorspace
,
1402 keyword
, profile_length
, profile_header
,
1403 png_ptr
->color_type
))
1405 /* Now read the tag table; a variable size buffer is
1406 * needed at this point, allocate one for the whole
1407 * profile. The header check has already validated
1408 * that none of these stuff will overflow.
1410 const png_uint_32 tag_count
= png_get_uint_32(
1411 profile_header
+128);
1412 png_bytep profile
= png_read_buffer(png_ptr
,
1413 profile_length
, 2/*silent*/);
1415 if (profile
!= NULL
)
1417 memcpy(profile
, profile_header
,
1418 (sizeof profile_header
));
1420 size
= 12 * tag_count
;
1422 (void)png_inflate_read(png_ptr
, local_buffer
,
1423 (sizeof local_buffer
), &length
,
1424 profile
+ (sizeof profile_header
), &size
, 0);
1426 /* Still expect a a buffer error because we expect
1427 * there to be some tag data!
1431 if (png_icc_check_tag_table(png_ptr
,
1432 &png_ptr
->colorspace
, keyword
, profile_length
,
1435 /* The profile has been validated for basic
1436 * security issues, so read the whole thing in.
1438 size
= profile_length
- (sizeof profile_header
)
1441 (void)png_inflate_read(png_ptr
, local_buffer
,
1442 (sizeof local_buffer
), &length
,
1443 profile
+ (sizeof profile_header
) +
1444 12 * tag_count
, &size
, 1/*finish*/);
1446 if (length
> 0 && !(png_ptr
->flags
&
1447 PNG_FLAG_BENIGN_ERRORS_WARN
))
1448 errmsg
= "extra compressed data";
1450 /* But otherwise allow extra data: */
1455 /* This can be handled completely, so
1458 png_chunk_warning(png_ptr
,
1459 "extra compressed data");
1462 png_crc_finish(png_ptr
, length
);
1465 # ifdef PNG_sRGB_SUPPORTED
1466 /* Check for a match against sRGB */
1467 png_icc_set_sRGB(png_ptr
,
1468 &png_ptr
->colorspace
, profile
,
1469 png_ptr
->zstream
.adler
);
1472 /* Steal the profile for info_ptr. */
1473 if (info_ptr
!= NULL
)
1475 png_free_data(png_ptr
, info_ptr
,
1478 info_ptr
->iccp_name
= png_voidcast(char*,
1479 png_malloc_base(png_ptr
,
1481 if (info_ptr
->iccp_name
!= NULL
)
1483 memcpy(info_ptr
->iccp_name
, keyword
,
1485 info_ptr
->iccp_proflen
=
1487 info_ptr
->iccp_profile
= profile
;
1488 png_ptr
->read_buffer
= NULL
; /*steal*/
1489 info_ptr
->free_me
|= PNG_FREE_ICCP
;
1490 info_ptr
->valid
|= PNG_INFO_iCCP
;
1495 png_ptr
->colorspace
.flags
|=
1496 PNG_COLORSPACE_INVALID
;
1497 errmsg
= "out of memory";
1501 /* else the profile remains in the read
1502 * buffer which gets reused for subsequent
1506 if (info_ptr
!= NULL
)
1507 png_colorspace_sync(png_ptr
, info_ptr
);
1511 png_ptr
->zowner
= 0;
1517 errmsg
= "truncated";
1520 errmsg
= png_ptr
->zstream
.msg
;
1523 /* else png_icc_check_tag_table output an error */
1526 else /* profile truncated */
1527 errmsg
= png_ptr
->zstream
.msg
;
1531 errmsg
= "out of memory";
1534 /* else png_icc_check_header output an error */
1537 /* else png_icc_check_length output an error */
1540 else /* profile truncated */
1541 errmsg
= png_ptr
->zstream
.msg
;
1543 /* Release the stream */
1544 png_ptr
->zowner
= 0;
1547 else /* png_inflate_claim failed */
1548 errmsg
= png_ptr
->zstream
.msg
;
1552 errmsg
= "bad compression method"; /* or missing */
1556 errmsg
= "bad keyword";
1560 errmsg
= "too many profiles";
1562 /* Failure: the reason is in 'errmsg' */
1564 png_crc_finish(png_ptr
, length
);
1566 png_ptr
->colorspace
.flags
|= PNG_COLORSPACE_INVALID
;
1567 png_colorspace_sync(png_ptr
, info_ptr
);
1568 if (errmsg
!= NULL
) /* else already output */
1569 png_chunk_benign_error(png_ptr
, errmsg
);
1571 #endif /* PNG_READ_iCCP_SUPPORTED */
1573 #ifdef PNG_READ_sPLT_SUPPORTED
1575 png_handle_sPLT(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1576 /* Note: this does not properly handle chunks that are > 64K under DOS */
1578 png_bytep entry_start
, buffer
;
1579 png_sPLT_t new_palette
;
1581 png_uint_32 data_length
;
1583 png_uint_32 skip
= 0;
1587 png_debug(1, "in png_handle_sPLT");
1589 #ifdef PNG_USER_LIMITS_SUPPORTED
1590 if (png_ptr
->user_chunk_cache_max
!= 0)
1592 if (png_ptr
->user_chunk_cache_max
== 1)
1594 png_crc_finish(png_ptr
, length
);
1598 if (--png_ptr
->user_chunk_cache_max
== 1)
1600 png_warning(png_ptr
, "No space in chunk cache for sPLT");
1601 png_crc_finish(png_ptr
, length
);
1607 if (!(png_ptr
->mode
& PNG_HAVE_IHDR
))
1608 png_chunk_error(png_ptr
, "missing IHDR");
1610 else if (png_ptr
->mode
& PNG_HAVE_IDAT
)
1612 png_crc_finish(png_ptr
, length
);
1613 png_chunk_benign_error(png_ptr
, "out of place");
1617 #ifdef PNG_MAX_MALLOC_64K
1618 if (length
> 65535U)
1620 png_crc_finish(png_ptr
, length
);
1621 png_chunk_benign_error(png_ptr
, "too large to fit in memory");
1626 buffer
= png_read_buffer(png_ptr
, length
+1, 2/*silent*/);
1629 png_crc_finish(png_ptr
, length
);
1630 png_chunk_benign_error(png_ptr
, "out of memory");
1635 /* WARNING: this may break if size_t is less than 32 bits; it is assumed
1636 * that the PNG_MAX_MALLOC_64K test is enabled in this case, but this is a
1637 * potential breakage point if the types in pngconf.h aren't exactly right.
1639 png_crc_read(png_ptr
, buffer
, length
);
1641 if (png_crc_finish(png_ptr
, skip
))
1646 for (entry_start
= buffer
; *entry_start
; entry_start
++)
1647 /* Empty loop to find end of name */ ;
1651 /* A sample depth should follow the separator, and we should be on it */
1652 if (entry_start
> buffer
+ length
- 2)
1654 png_warning(png_ptr
, "malformed sPLT chunk");
1658 new_palette
.depth
= *entry_start
++;
1659 entry_size
= (new_palette
.depth
== 8 ?
6 : 10);
1660 /* This must fit in a png_uint_32 because it is derived from the original
1661 * chunk data length.
1663 data_length
= length
- (png_uint_32
)(entry_start
- buffer
);
1665 /* Integrity-check the data length */
1666 if (data_length
% entry_size
)
1668 png_warning(png_ptr
, "sPLT chunk has bad length");
1672 dl
= (png_int_32
)(data_length
/ entry_size
);
1673 max_dl
= PNG_SIZE_MAX
/ (sizeof (png_sPLT_entry
));
1677 png_warning(png_ptr
, "sPLT chunk too long");
1681 new_palette
.nentries
= (png_int_32
)(data_length
/ entry_size
);
1683 new_palette
.entries
= (png_sPLT_entryp
)png_malloc_warn(
1684 png_ptr
, new_palette
.nentries
* (sizeof (png_sPLT_entry
)));
1686 if (new_palette
.entries
== NULL
)
1688 png_warning(png_ptr
, "sPLT chunk requires too much memory");
1692 #ifdef PNG_POINTER_INDEXING_SUPPORTED
1693 for (i
= 0; i
< new_palette
.nentries
; i
++)
1695 pp
= new_palette
.entries
+ i
;
1697 if (new_palette
.depth
== 8)
1699 pp
->red
= *entry_start
++;
1700 pp
->green
= *entry_start
++;
1701 pp
->blue
= *entry_start
++;
1702 pp
->alpha
= *entry_start
++;
1707 pp
->red
= png_get_uint_16(entry_start
); entry_start
+= 2;
1708 pp
->green
= png_get_uint_16(entry_start
); entry_start
+= 2;
1709 pp
->blue
= png_get_uint_16(entry_start
); entry_start
+= 2;
1710 pp
->alpha
= png_get_uint_16(entry_start
); entry_start
+= 2;
1713 pp
->frequency
= png_get_uint_16(entry_start
); entry_start
+= 2;
1716 pp
= new_palette
.entries
;
1718 for (i
= 0; i
< new_palette
.nentries
; i
++)
1721 if (new_palette
.depth
== 8)
1723 pp
[i
].red
= *entry_start
++;
1724 pp
[i
].green
= *entry_start
++;
1725 pp
[i
].blue
= *entry_start
++;
1726 pp
[i
].alpha
= *entry_start
++;
1731 pp
[i
].red
= png_get_uint_16(entry_start
); entry_start
+= 2;
1732 pp
[i
].green
= png_get_uint_16(entry_start
); entry_start
+= 2;
1733 pp
[i
].blue
= png_get_uint_16(entry_start
); entry_start
+= 2;
1734 pp
[i
].alpha
= png_get_uint_16(entry_start
); entry_start
+= 2;
1737 pp
[i
].frequency
= png_get_uint_16(entry_start
); entry_start
+= 2;
1741 /* Discard all chunk data except the name and stash that */
1742 new_palette
.name
= (png_charp
)buffer
;
1744 png_set_sPLT(png_ptr
, info_ptr
, &new_palette
, 1);
1746 png_free(png_ptr
, new_palette
.entries
);
1748 #endif /* PNG_READ_sPLT_SUPPORTED */
1750 #ifdef PNG_READ_tRNS_SUPPORTED
1752 png_handle_tRNS(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1754 png_byte readbuf
[PNG_MAX_PALETTE_LENGTH
];
1756 png_debug(1, "in png_handle_tRNS");
1758 if (!(png_ptr
->mode
& PNG_HAVE_IHDR
))
1759 png_chunk_error(png_ptr
, "missing IHDR");
1761 else if (png_ptr
->mode
& PNG_HAVE_IDAT
)
1763 png_crc_finish(png_ptr
, length
);
1764 png_chunk_benign_error(png_ptr
, "out of place");
1768 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_tRNS
))
1770 png_crc_finish(png_ptr
, length
);
1771 png_chunk_benign_error(png_ptr
, "duplicate");
1775 if (png_ptr
->color_type
== PNG_COLOR_TYPE_GRAY
)
1781 png_crc_finish(png_ptr
, length
);
1782 png_chunk_benign_error(png_ptr
, "invalid");
1786 png_crc_read(png_ptr
, buf
, 2);
1787 png_ptr
->num_trans
= 1;
1788 png_ptr
->trans_color
.gray
= png_get_uint_16(buf
);
1791 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_RGB
)
1797 png_crc_finish(png_ptr
, length
);
1798 png_chunk_benign_error(png_ptr
, "invalid");
1802 png_crc_read(png_ptr
, buf
, length
);
1803 png_ptr
->num_trans
= 1;
1804 png_ptr
->trans_color
.red
= png_get_uint_16(buf
);
1805 png_ptr
->trans_color
.green
= png_get_uint_16(buf
+ 2);
1806 png_ptr
->trans_color
.blue
= png_get_uint_16(buf
+ 4);
1809 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
1811 if (!(png_ptr
->mode
& PNG_HAVE_PLTE
))
1813 /* TODO: is this actually an error in the ISO spec? */
1814 png_crc_finish(png_ptr
, length
);
1815 png_chunk_benign_error(png_ptr
, "out of place");
1819 if (length
> png_ptr
->num_palette
|| length
> PNG_MAX_PALETTE_LENGTH
||
1822 png_crc_finish(png_ptr
, length
);
1823 png_chunk_benign_error(png_ptr
, "invalid");
1827 png_crc_read(png_ptr
, readbuf
, length
);
1828 png_ptr
->num_trans
= (png_uint_16
)length
;
1833 png_crc_finish(png_ptr
, length
);
1834 png_chunk_benign_error(png_ptr
, "invalid with alpha channel");
1838 if (png_crc_finish(png_ptr
, 0))
1840 png_ptr
->num_trans
= 0;
1844 /* TODO: this is a horrible side effect in the palette case because the
1845 * png_struct ends up with a pointer to the tRNS buffer owned by the
1846 * png_info. Fix this.
1848 png_set_tRNS(png_ptr
, info_ptr
, readbuf
, png_ptr
->num_trans
,
1849 &(png_ptr
->trans_color
));
1853 #ifdef PNG_READ_bKGD_SUPPORTED
1855 png_handle_bKGD(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1857 unsigned int truelen
;
1859 png_color_16 background
;
1861 png_debug(1, "in png_handle_bKGD");
1863 if (!(png_ptr
->mode
& PNG_HAVE_IHDR
))
1864 png_chunk_error(png_ptr
, "missing IHDR");
1866 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) ||
1867 (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
&&
1868 !(png_ptr
->mode
& PNG_HAVE_PLTE
)))
1870 png_crc_finish(png_ptr
, length
);
1871 png_chunk_benign_error(png_ptr
, "out of place");
1875 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_bKGD
))
1877 png_crc_finish(png_ptr
, length
);
1878 png_chunk_benign_error(png_ptr
, "duplicate");
1882 if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
1885 else if (png_ptr
->color_type
& PNG_COLOR_MASK_COLOR
)
1891 if (length
!= truelen
)
1893 png_crc_finish(png_ptr
, length
);
1894 png_chunk_benign_error(png_ptr
, "invalid");
1898 png_crc_read(png_ptr
, buf
, truelen
);
1900 if (png_crc_finish(png_ptr
, 0))
1903 /* We convert the index value into RGB components so that we can allow
1904 * arbitrary RGB values for background when we have transparency, and
1905 * so it is easy to determine the RGB values of the background color
1906 * from the info_ptr struct.
1908 if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
1910 background
.index
= buf
[0];
1912 if (info_ptr
&& info_ptr
->num_palette
)
1914 if (buf
[0] >= info_ptr
->num_palette
)
1916 png_chunk_benign_error(png_ptr
, "invalid index");
1920 background
.red
= (png_uint_16
)png_ptr
->palette
[buf
[0]].red
;
1921 background
.green
= (png_uint_16
)png_ptr
->palette
[buf
[0]].green
;
1922 background
.blue
= (png_uint_16
)png_ptr
->palette
[buf
[0]].blue
;
1926 background
.red
= background
.green
= background
.blue
= 0;
1928 background
.gray
= 0;
1931 else if (!(png_ptr
->color_type
& PNG_COLOR_MASK_COLOR
)) /* GRAY */
1933 background
.index
= 0;
1937 background
.gray
= png_get_uint_16(buf
);
1942 background
.index
= 0;
1943 background
.red
= png_get_uint_16(buf
);
1944 background
.green
= png_get_uint_16(buf
+ 2);
1945 background
.blue
= png_get_uint_16(buf
+ 4);
1946 background
.gray
= 0;
1949 png_set_bKGD(png_ptr
, info_ptr
, &background
);
1953 #ifdef PNG_READ_hIST_SUPPORTED
1955 png_handle_hIST(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
1957 unsigned int num
, i
;
1958 png_uint_16 readbuf
[PNG_MAX_PALETTE_LENGTH
];
1960 png_debug(1, "in png_handle_hIST");
1962 if (!(png_ptr
->mode
& PNG_HAVE_IHDR
))
1963 png_chunk_error(png_ptr
, "missing IHDR");
1965 else if ((png_ptr
->mode
& PNG_HAVE_IDAT
) || !(png_ptr
->mode
& PNG_HAVE_PLTE
))
1967 png_crc_finish(png_ptr
, length
);
1968 png_chunk_benign_error(png_ptr
, "out of place");
1972 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_hIST
))
1974 png_crc_finish(png_ptr
, length
);
1975 png_chunk_benign_error(png_ptr
, "duplicate");
1981 if (num
!= png_ptr
->num_palette
|| num
> PNG_MAX_PALETTE_LENGTH
)
1983 png_crc_finish(png_ptr
, length
);
1984 png_chunk_benign_error(png_ptr
, "invalid");
1988 for (i
= 0; i
< num
; i
++)
1992 png_crc_read(png_ptr
, buf
, 2);
1993 readbuf
[i
] = png_get_uint_16(buf
);
1996 if (png_crc_finish(png_ptr
, 0))
1999 png_set_hIST(png_ptr
, info_ptr
, readbuf
);
2003 #ifdef PNG_READ_pHYs_SUPPORTED
2005 png_handle_pHYs(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2008 png_uint_32 res_x
, res_y
;
2011 png_debug(1, "in png_handle_pHYs");
2013 if (!(png_ptr
->mode
& PNG_HAVE_IHDR
))
2014 png_chunk_error(png_ptr
, "missing IHDR");
2016 else if (png_ptr
->mode
& PNG_HAVE_IDAT
)
2018 png_crc_finish(png_ptr
, length
);
2019 png_chunk_benign_error(png_ptr
, "out of place");
2023 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_pHYs
))
2025 png_crc_finish(png_ptr
, length
);
2026 png_chunk_benign_error(png_ptr
, "duplicate");
2032 png_crc_finish(png_ptr
, length
);
2033 png_chunk_benign_error(png_ptr
, "invalid");
2037 png_crc_read(png_ptr
, buf
, 9);
2039 if (png_crc_finish(png_ptr
, 0))
2042 res_x
= png_get_uint_32(buf
);
2043 res_y
= png_get_uint_32(buf
+ 4);
2045 png_set_pHYs(png_ptr
, info_ptr
, res_x
, res_y
, unit_type
);
2049 #ifdef PNG_READ_oFFs_SUPPORTED
2051 png_handle_oFFs(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2054 png_int_32 offset_x
, offset_y
;
2057 png_debug(1, "in png_handle_oFFs");
2059 if (!(png_ptr
->mode
& PNG_HAVE_IHDR
))
2060 png_chunk_error(png_ptr
, "missing IHDR");
2062 else if (png_ptr
->mode
& PNG_HAVE_IDAT
)
2064 png_crc_finish(png_ptr
, length
);
2065 png_chunk_benign_error(png_ptr
, "out of place");
2069 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_oFFs
))
2071 png_crc_finish(png_ptr
, length
);
2072 png_chunk_benign_error(png_ptr
, "duplicate");
2078 png_crc_finish(png_ptr
, length
);
2079 png_chunk_benign_error(png_ptr
, "invalid");
2083 png_crc_read(png_ptr
, buf
, 9);
2085 if (png_crc_finish(png_ptr
, 0))
2088 offset_x
= png_get_int_32(buf
);
2089 offset_y
= png_get_int_32(buf
+ 4);
2091 png_set_oFFs(png_ptr
, info_ptr
, offset_x
, offset_y
, unit_type
);
2095 #ifdef PNG_READ_pCAL_SUPPORTED
2096 /* Read the pCAL chunk (described in the PNG Extensions document) */
2098 png_handle_pCAL(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2101 png_byte type
, nparams
;
2102 png_bytep buffer
, buf
, units
, endptr
;
2106 png_debug(1, "in png_handle_pCAL");
2108 if (!(png_ptr
->mode
& PNG_HAVE_IHDR
))
2109 png_chunk_error(png_ptr
, "missing IHDR");
2111 else if (png_ptr
->mode
& PNG_HAVE_IDAT
)
2113 png_crc_finish(png_ptr
, length
);
2114 png_chunk_benign_error(png_ptr
, "out of place");
2118 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_pCAL
))
2120 png_crc_finish(png_ptr
, length
);
2121 png_chunk_benign_error(png_ptr
, "duplicate");
2125 png_debug1(2, "Allocating and reading pCAL chunk data (%u bytes)",
2128 buffer
= png_read_buffer(png_ptr
, length
+1, 2/*silent*/);
2132 png_crc_finish(png_ptr
, length
);
2133 png_chunk_benign_error(png_ptr
, "out of memory");
2137 png_crc_read(png_ptr
, buffer
, length
);
2139 if (png_crc_finish(png_ptr
, 0))
2142 buffer
[length
] = 0; /* Null terminate the last string */
2144 png_debug(3, "Finding end of pCAL purpose string");
2145 for (buf
= buffer
; *buf
; buf
++)
2148 endptr
= buffer
+ length
;
2150 /* We need to have at least 12 bytes after the purpose string
2151 * in order to get the parameter information.
2153 if (endptr
<= buf
+ 12)
2155 png_chunk_benign_error(png_ptr
, "invalid");
2159 png_debug(3, "Reading pCAL X0, X1, type, nparams, and units");
2160 X0
= png_get_int_32((png_bytep
)buf
+1);
2161 X1
= png_get_int_32((png_bytep
)buf
+5);
2166 png_debug(3, "Checking pCAL equation type and number of parameters");
2167 /* Check that we have the right number of parameters for known
2170 if ((type
== PNG_EQUATION_LINEAR
&& nparams
!= 2) ||
2171 (type
== PNG_EQUATION_BASE_E
&& nparams
!= 3) ||
2172 (type
== PNG_EQUATION_ARBITRARY
&& nparams
!= 3) ||
2173 (type
== PNG_EQUATION_HYPERBOLIC
&& nparams
!= 4))
2175 png_chunk_benign_error(png_ptr
, "invalid parameter count");
2179 else if (type
>= PNG_EQUATION_LAST
)
2181 png_chunk_benign_error(png_ptr
, "unrecognized equation type");
2184 for (buf
= units
; *buf
; buf
++)
2185 /* Empty loop to move past the units string. */ ;
2187 png_debug(3, "Allocating pCAL parameters array");
2189 params
= png_voidcast(png_charpp
, png_malloc_warn(png_ptr
,
2190 nparams
* (sizeof (png_charp
))));
2194 png_chunk_benign_error(png_ptr
, "out of memory");
2198 /* Get pointers to the start of each parameter string. */
2199 for (i
= 0; i
< nparams
; i
++)
2201 buf
++; /* Skip the null string terminator from previous parameter. */
2203 png_debug1(3, "Reading pCAL parameter %d", i
);
2205 for (params
[i
] = (png_charp
)buf
; buf
<= endptr
&& *buf
!= 0; buf
++)
2206 /* Empty loop to move past each parameter string */ ;
2208 /* Make sure we haven't run out of data yet */
2211 png_free(png_ptr
, params
);
2212 png_chunk_benign_error(png_ptr
, "invalid data");
2217 png_set_pCAL(png_ptr
, info_ptr
, (png_charp
)buffer
, X0
, X1
, type
, nparams
,
2218 (png_charp
)units
, params
);
2220 png_free(png_ptr
, params
);
2224 #ifdef PNG_READ_sCAL_SUPPORTED
2225 /* Read the sCAL chunk */
2227 png_handle_sCAL(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2233 png_debug(1, "in png_handle_sCAL");
2235 if (!(png_ptr
->mode
& PNG_HAVE_IHDR
))
2236 png_chunk_error(png_ptr
, "missing IHDR");
2238 else if (png_ptr
->mode
& PNG_HAVE_IDAT
)
2240 png_crc_finish(png_ptr
, length
);
2241 png_chunk_benign_error(png_ptr
, "out of place");
2245 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_sCAL
))
2247 png_crc_finish(png_ptr
, length
);
2248 png_chunk_benign_error(png_ptr
, "duplicate");
2252 /* Need unit type, width, \0, height: minimum 4 bytes */
2253 else if (length
< 4)
2255 png_crc_finish(png_ptr
, length
);
2256 png_chunk_benign_error(png_ptr
, "invalid");
2260 png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)",
2263 buffer
= png_read_buffer(png_ptr
, length
+1, 2/*silent*/);
2267 png_chunk_benign_error(png_ptr
, "out of memory");
2268 png_crc_finish(png_ptr
, length
);
2272 png_crc_read(png_ptr
, buffer
, length
);
2273 buffer
[length
] = 0; /* Null terminate the last string */
2275 if (png_crc_finish(png_ptr
, 0))
2278 /* Validate the unit. */
2279 if (buffer
[0] != 1 && buffer
[0] != 2)
2281 png_chunk_benign_error(png_ptr
, "invalid unit");
2285 /* Validate the ASCII numbers, need two ASCII numbers separated by
2286 * a '\0' and they need to fit exactly in the chunk data.
2291 if (!png_check_fp_number((png_const_charp
)buffer
, length
, &state
, &i
) ||
2292 i
>= length
|| buffer
[i
++] != 0)
2293 png_chunk_benign_error(png_ptr
, "bad width format");
2295 else if (!PNG_FP_IS_POSITIVE(state
))
2296 png_chunk_benign_error(png_ptr
, "non-positive width");
2300 png_size_t heighti
= i
;
2303 if (!png_check_fp_number((png_const_charp
)buffer
, length
, &state
, &i
) ||
2305 png_chunk_benign_error(png_ptr
, "bad height format");
2307 else if (!PNG_FP_IS_POSITIVE(state
))
2308 png_chunk_benign_error(png_ptr
, "non-positive height");
2311 /* This is the (only) success case. */
2312 png_set_sCAL_s(png_ptr
, info_ptr
, buffer
[0],
2313 (png_charp
)buffer
+1, (png_charp
)buffer
+heighti
);
2318 #ifdef PNG_READ_tIME_SUPPORTED
2320 png_handle_tIME(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2325 png_debug(1, "in png_handle_tIME");
2327 if (!(png_ptr
->mode
& PNG_HAVE_IHDR
))
2328 png_chunk_error(png_ptr
, "missing IHDR");
2330 else if (info_ptr
!= NULL
&& (info_ptr
->valid
& PNG_INFO_tIME
))
2332 png_crc_finish(png_ptr
, length
);
2333 png_chunk_benign_error(png_ptr
, "duplicate");
2337 if (png_ptr
->mode
& PNG_HAVE_IDAT
)
2338 png_ptr
->mode
|= PNG_AFTER_IDAT
;
2342 png_crc_finish(png_ptr
, length
);
2343 png_chunk_benign_error(png_ptr
, "invalid");
2347 png_crc_read(png_ptr
, buf
, 7);
2349 if (png_crc_finish(png_ptr
, 0))
2352 mod_time
.second
= buf
[6];
2353 mod_time
.minute
= buf
[5];
2354 mod_time
.hour
= buf
[4];
2355 mod_time
.day
= buf
[3];
2356 mod_time
.month
= buf
[2];
2357 mod_time
.year
= png_get_uint_16(buf
);
2359 png_set_tIME(png_ptr
, info_ptr
, &mod_time
);
2363 #ifdef PNG_READ_tEXt_SUPPORTED
2364 /* Note: this does not properly handle chunks that are > 64K under DOS */
2366 png_handle_tEXt(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2372 png_uint_32 skip
= 0;
2374 png_debug(1, "in png_handle_tEXt");
2376 #ifdef PNG_USER_LIMITS_SUPPORTED
2377 if (png_ptr
->user_chunk_cache_max
!= 0)
2379 if (png_ptr
->user_chunk_cache_max
== 1)
2381 png_crc_finish(png_ptr
, length
);
2385 if (--png_ptr
->user_chunk_cache_max
== 1)
2387 png_crc_finish(png_ptr
, length
);
2388 png_chunk_benign_error(png_ptr
, "no space in chunk cache");
2394 if (!(png_ptr
->mode
& PNG_HAVE_IHDR
))
2395 png_chunk_error(png_ptr
, "missing IHDR");
2397 if (png_ptr
->mode
& PNG_HAVE_IDAT
)
2398 png_ptr
->mode
|= PNG_AFTER_IDAT
;
2400 #ifdef PNG_MAX_MALLOC_64K
2401 if (length
> 65535U)
2403 png_crc_finish(png_ptr
, length
);
2404 png_chunk_benign_error(png_ptr
, "too large to fit in memory");
2409 buffer
= png_read_buffer(png_ptr
, length
+1, 1/*warn*/);
2413 png_chunk_benign_error(png_ptr
, "out of memory");
2417 png_crc_read(png_ptr
, buffer
, length
);
2419 if (png_crc_finish(png_ptr
, skip
))
2422 key
= (png_charp
)buffer
;
2425 for (text
= key
; *text
; text
++)
2426 /* Empty loop to find end of key */ ;
2428 if (text
!= key
+ length
)
2431 text_info
.compression
= PNG_TEXT_COMPRESSION_NONE
;
2432 text_info
.key
= key
;
2433 text_info
.lang
= NULL
;
2434 text_info
.lang_key
= NULL
;
2435 text_info
.itxt_length
= 0;
2436 text_info
.text
= text
;
2437 text_info
.text_length
= strlen(text
);
2439 if (png_set_text_2(png_ptr
, info_ptr
, &text_info
, 1))
2440 png_warning(png_ptr
, "Insufficient memory to process text chunk");
2444 #ifdef PNG_READ_zTXt_SUPPORTED
2445 /* Note: this does not correctly handle chunks that are > 64K under DOS */
2447 png_handle_zTXt(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2449 png_const_charp errmsg
= NULL
;
2451 png_uint_32 keyword_length
;
2453 png_debug(1, "in png_handle_zTXt");
2455 #ifdef PNG_USER_LIMITS_SUPPORTED
2456 if (png_ptr
->user_chunk_cache_max
!= 0)
2458 if (png_ptr
->user_chunk_cache_max
== 1)
2460 png_crc_finish(png_ptr
, length
);
2464 if (--png_ptr
->user_chunk_cache_max
== 1)
2466 png_crc_finish(png_ptr
, length
);
2467 png_chunk_benign_error(png_ptr
, "no space in chunk cache");
2473 if (!(png_ptr
->mode
& PNG_HAVE_IHDR
))
2474 png_chunk_error(png_ptr
, "missing IHDR");
2476 if (png_ptr
->mode
& PNG_HAVE_IDAT
)
2477 png_ptr
->mode
|= PNG_AFTER_IDAT
;
2479 buffer
= png_read_buffer(png_ptr
, length
, 2/*silent*/);
2483 png_crc_finish(png_ptr
, length
);
2484 png_chunk_benign_error(png_ptr
, "out of memory");
2488 png_crc_read(png_ptr
, buffer
, length
);
2490 if (png_crc_finish(png_ptr
, 0))
2493 /* TODO: also check that the keyword contents match the spec! */
2494 for (keyword_length
= 0;
2495 keyword_length
< length
&& buffer
[keyword_length
] != 0;
2497 /* Empty loop to find end of name */ ;
2499 if (keyword_length
> 79 || keyword_length
< 1)
2500 errmsg
= "bad keyword";
2502 /* zTXt must have some LZ data after the keyword, although it may expand to
2503 * zero bytes; we need a '\0' at the end of the keyword, the compression type
2506 else if (keyword_length
+ 3 > length
)
2507 errmsg
= "truncated";
2509 else if (buffer
[keyword_length
+1] != PNG_COMPRESSION_TYPE_BASE
)
2510 errmsg
= "unknown compression type";
2514 png_alloc_size_t uncompressed_length
= PNG_SIZE_MAX
;
2516 /* TODO: at present png_decompress_chunk imposes a single application
2517 * level memory limit, this should be split to different values for iCCP
2520 if (png_decompress_chunk(png_ptr
, length
, keyword_length
+2,
2521 &uncompressed_length
, 1/*terminate*/) == Z_STREAM_END
)
2525 /* It worked; png_ptr->read_buffer now looks like a tEXt chunk except
2526 * for the extra compression type byte and the fact that it isn't
2527 * necessarily '\0' terminated.
2529 buffer
= png_ptr
->read_buffer
;
2530 buffer
[uncompressed_length
+(keyword_length
+2)] = 0;
2532 text
.compression
= PNG_TEXT_COMPRESSION_zTXt
;
2533 text
.key
= (png_charp
)buffer
;
2534 text
.text
= (png_charp
)(buffer
+ keyword_length
+2);
2535 text
.text_length
= uncompressed_length
;
2536 text
.itxt_length
= 0;
2538 text
.lang_key
= NULL
;
2540 if (png_set_text_2(png_ptr
, info_ptr
, &text
, 1))
2541 errmsg
= "insufficient memory";
2545 errmsg
= png_ptr
->zstream
.msg
;
2549 png_chunk_benign_error(png_ptr
, errmsg
);
2553 #ifdef PNG_READ_iTXt_SUPPORTED
2554 /* Note: this does not correctly handle chunks that are > 64K under DOS */
2556 png_handle_iTXt(png_structrp png_ptr
, png_inforp info_ptr
, png_uint_32 length
)
2558 png_const_charp errmsg
= NULL
;
2560 png_uint_32 prefix_length
;
2562 png_debug(1, "in png_handle_iTXt");
2564 #ifdef PNG_USER_LIMITS_SUPPORTED
2565 if (png_ptr
->user_chunk_cache_max
!= 0)
2567 if (png_ptr
->user_chunk_cache_max
== 1)
2569 png_crc_finish(png_ptr
, length
);
2573 if (--png_ptr
->user_chunk_cache_max
== 1)
2575 png_crc_finish(png_ptr
, length
);
2576 png_chunk_benign_error(png_ptr
, "no space in chunk cache");
2582 if (!(png_ptr
->mode
& PNG_HAVE_IHDR
))
2583 png_chunk_error(png_ptr
, "missing IHDR");
2585 if (png_ptr
->mode
& PNG_HAVE_IDAT
)
2586 png_ptr
->mode
|= PNG_AFTER_IDAT
;
2588 buffer
= png_read_buffer(png_ptr
, length
+1, 1/*warn*/);
2592 png_crc_finish(png_ptr
, length
);
2593 png_chunk_benign_error(png_ptr
, "out of memory");
2597 png_crc_read(png_ptr
, buffer
, length
);
2599 if (png_crc_finish(png_ptr
, 0))
2602 /* First the keyword. */
2603 for (prefix_length
=0;
2604 prefix_length
< length
&& buffer
[prefix_length
] != 0;
2608 /* Perform a basic check on the keyword length here. */
2609 if (prefix_length
> 79 || prefix_length
< 1)
2610 errmsg
= "bad keyword";
2612 /* Expect keyword, compression flag, compression type, language, translated
2613 * keyword (both may be empty but are 0 terminated) then the text, which may
2616 else if (prefix_length
+ 5 > length
)
2617 errmsg
= "truncated";
2619 else if (buffer
[prefix_length
+1] == 0 ||
2620 (buffer
[prefix_length
+1] == 1 &&
2621 buffer
[prefix_length
+2] == PNG_COMPRESSION_TYPE_BASE
))
2623 int compressed
= buffer
[prefix_length
+1] != 0;
2624 png_uint_32 language_offset
, translated_keyword_offset
;
2625 png_alloc_size_t uncompressed_length
= 0;
2627 /* Now the language tag */
2629 language_offset
= prefix_length
;
2631 for (; prefix_length
< length
&& buffer
[prefix_length
] != 0;
2635 /* WARNING: the length may be invalid here, this is checked below. */
2636 translated_keyword_offset
= ++prefix_length
;
2638 for (; prefix_length
< length
&& buffer
[prefix_length
] != 0;
2642 /* prefix_length should now be at the trailing '\0' of the translated
2643 * keyword, but it may already be over the end. None of this arithmetic
2644 * can overflow because chunks are at most 2^31 bytes long, but on 16-bit
2645 * systems the available allocaton may overflow.
2649 if (!compressed
&& prefix_length
<= length
)
2650 uncompressed_length
= length
- prefix_length
;
2652 else if (compressed
&& prefix_length
< length
)
2654 uncompressed_length
= PNG_SIZE_MAX
;
2656 /* TODO: at present png_decompress_chunk imposes a single application
2657 * level memory limit, this should be split to different values for
2658 * iCCP and text chunks.
2660 if (png_decompress_chunk(png_ptr
, length
, prefix_length
,
2661 &uncompressed_length
, 1/*terminate*/) == Z_STREAM_END
)
2662 buffer
= png_ptr
->read_buffer
;
2665 errmsg
= png_ptr
->zstream
.msg
;
2669 errmsg
= "truncated";
2675 buffer
[uncompressed_length
+prefix_length
] = 0;
2678 text
.compression
= PNG_ITXT_COMPRESSION_NONE
;
2681 text
.compression
= PNG_ITXT_COMPRESSION_zTXt
;
2683 text
.key
= (png_charp
)buffer
;
2684 text
.lang
= (png_charp
)buffer
+ language_offset
;
2685 text
.lang_key
= (png_charp
)buffer
+ translated_keyword_offset
;
2686 text
.text
= (png_charp
)buffer
+ prefix_length
;
2687 text
.text_length
= 0;
2688 text
.itxt_length
= uncompressed_length
;
2690 if (png_set_text_2(png_ptr
, info_ptr
, &text
, 1))
2691 errmsg
= "insufficient memory";
2696 errmsg
= "bad compression info";
2699 png_chunk_benign_error(png_ptr
, errmsg
);
2703 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
2704 /* Utility function for png_handle_unknown; set up png_ptr::unknown_chunk */
2706 png_cache_unknown_chunk(png_structrp png_ptr
, png_uint_32 length
)
2708 png_alloc_size_t limit
= PNG_SIZE_MAX
;
2710 if (png_ptr
->unknown_chunk
.data
!= NULL
)
2712 png_free(png_ptr
, png_ptr
->unknown_chunk
.data
);
2713 png_ptr
->unknown_chunk
.data
= NULL
;
2716 # ifdef PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED
2717 if (png_ptr
->user_chunk_malloc_max
> 0 &&
2718 png_ptr
->user_chunk_malloc_max
< limit
)
2719 limit
= png_ptr
->user_chunk_malloc_max
;
2721 # elif PNG_USER_CHUNK_MALLOC_MAX > 0
2722 if (PNG_USER_CHUNK_MALLOC_MAX
< limit
)
2723 limit
= PNG_USER_CHUNK_MALLOC_MAX
;
2726 if (length
<= limit
)
2728 PNG_CSTRING_FROM_CHUNK(png_ptr
->unknown_chunk
.name
, png_ptr
->chunk_name
);
2729 /* The following is safe because of the PNG_SIZE_MAX init above */
2730 png_ptr
->unknown_chunk
.size
= (png_size_t
)length
/*SAFE*/;
2731 /* 'mode' is a flag array, only the bottom four bits matter here */
2732 png_ptr
->unknown_chunk
.location
= (png_byte
)png_ptr
->mode
/*SAFE*/;
2735 png_ptr
->unknown_chunk
.data
= NULL
;
2739 /* Do a 'warn' here - it is handled below. */
2740 png_ptr
->unknown_chunk
.data
= png_voidcast(png_bytep
,
2741 png_malloc_warn(png_ptr
, length
));
2745 if (png_ptr
->unknown_chunk
.data
== NULL
&& length
> 0)
2747 /* This is benign because we clean up correctly */
2748 png_crc_finish(png_ptr
, length
);
2749 png_chunk_benign_error(png_ptr
, "unknown chunk exceeds memory limits");
2756 png_crc_read(png_ptr
, png_ptr
->unknown_chunk
.data
, length
);
2757 png_crc_finish(png_ptr
, 0);
2761 #endif /* PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */
2763 /* Handle an unknown, or known but disabled, chunk */
2765 png_handle_unknown(png_structrp png_ptr
, png_inforp info_ptr
,
2766 png_uint_32 length
, int keep
)
2768 int handled
= 0; /* the chunk was handled */
2770 png_debug(1, "in png_handle_unknown");
2772 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
2773 /* NOTE: this code is based on the code in libpng-1.4.12 except for fixing
2774 * the bug which meant that setting a non-default behavior for a specific
2775 * chunk would be ignored (the default was always used unless a user
2776 * callback was installed).
2778 * 'keep' is the value from the png_chunk_unknown_handling, the setting for
2779 * this specific chunk_name, if PNG_HANDLE_AS_UNKNOWN_SUPPORTED, if not it
2780 * will always be PNG_HANDLE_CHUNK_AS_DEFAULT and it needs to be set here.
2781 * This is just an optimization to avoid multiple calls to the lookup
2784 # ifndef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
2785 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
2786 keep
= png_chunk_unknown_handling(png_ptr
, png_ptr
->chunk_name
);
2790 /* One of the following methods will read the chunk or skip it (at least one
2791 * of these is always defined because this is the only way to switch on
2792 * PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
2794 # ifdef PNG_READ_USER_CHUNKS_SUPPORTED
2795 /* The user callback takes precedence over the chunk keep value, but the
2796 * keep value is still required to validate a save of a critical chunk.
2798 if (png_ptr
->read_user_chunk_fn
!= NULL
)
2800 if (png_cache_unknown_chunk(png_ptr
, length
))
2802 /* Callback to user unknown chunk handler */
2803 int ret
= (*(png_ptr
->read_user_chunk_fn
))(png_ptr
,
2804 &png_ptr
->unknown_chunk
);
2807 * negative: An error occured, png_chunk_error will be called.
2808 * zero: The chunk was not handled, the chunk will be discarded
2809 * unless png_set_keep_unknown_chunks has been used to set
2810 * a 'keep' behavior for this particular chunk, in which
2811 * case that will be used. A critical chunk will cause an
2812 * error at this point unless it is to be saved.
2813 * positive: The chunk was handled, libpng will ignore/discard it.
2816 png_chunk_error(png_ptr
, "error in user chunk");
2820 /* If the keep value is 'default' or 'never' override it, but
2821 * still error out on critical chunks unless the keep value is
2822 * 'always' While this is weird it is the behavior in 1.4.12.
2823 * A possible improvement would be to obey the value set for the
2824 * chunk, but this would be an API change that would probably
2825 * damage some applications.
2827 * The png_app_warning below catches the case that matters, where
2828 * the application has not set specific save or ignore for this
2829 * chunk or global save or ignore.
2831 if (keep
< PNG_HANDLE_CHUNK_IF_SAFE
)
2833 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
2834 if (png_ptr
->unknown_default
< PNG_HANDLE_CHUNK_IF_SAFE
)
2836 png_chunk_warning(png_ptr
, "Saving unknown chunk:");
2837 png_app_warning(png_ptr
,
2838 "forcing save of an unhandled chunk;"
2839 " please call png_set_keep_unknown_chunks");
2840 /* with keep = PNG_HANDLE_CHUNK_IF_SAFE */
2843 keep
= PNG_HANDLE_CHUNK_IF_SAFE
;
2847 else /* chunk was handled */
2850 /* Critical chunks can be safely discarded at this point. */
2851 keep
= PNG_HANDLE_CHUNK_NEVER
;
2856 keep
= PNG_HANDLE_CHUNK_NEVER
; /* insufficient memory */
2860 /* Use the SAVE_UNKNOWN_CHUNKS code or skip the chunk */
2861 # endif /* PNG_READ_USER_CHUNKS_SUPPORTED */
2863 # ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
2865 /* keep is currently just the per-chunk setting, if there was no
2866 * setting change it to the global default now (not that this may
2867 * still be AS_DEFAULT) then obtain the cache of the chunk if required,
2868 * if not simply skip the chunk.
2870 if (keep
== PNG_HANDLE_CHUNK_AS_DEFAULT
)
2871 keep
= png_ptr
->unknown_default
;
2873 if (keep
== PNG_HANDLE_CHUNK_ALWAYS
||
2874 (keep
== PNG_HANDLE_CHUNK_IF_SAFE
&&
2875 PNG_CHUNK_ANCILLARY(png_ptr
->chunk_name
)))
2877 if (!png_cache_unknown_chunk(png_ptr
, length
))
2878 keep
= PNG_HANDLE_CHUNK_NEVER
;
2882 png_crc_finish(png_ptr
, length
);
2885 # ifndef PNG_READ_USER_CHUNKS_SUPPORTED
2886 # error no method to support READ_UNKNOWN_CHUNKS
2890 /* If here there is no read callback pointer set and no support is
2891 * compiled in to just save the unknown chunks, so simply skip this
2892 * chunk. If 'keep' is something other than AS_DEFAULT or NEVER then
2893 * the app has erroneously asked for unknown chunk saving when there
2896 if (keep
> PNG_HANDLE_CHUNK_NEVER
)
2897 png_app_error(png_ptr
, "no unknown chunk support available");
2899 png_crc_finish(png_ptr
, length
);
2903 # ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
2904 /* Now store the chunk in the chunk list if appropriate, and if the limits
2907 if (keep
== PNG_HANDLE_CHUNK_ALWAYS
||
2908 (keep
== PNG_HANDLE_CHUNK_IF_SAFE
&&
2909 PNG_CHUNK_ANCILLARY(png_ptr
->chunk_name
)))
2911 # ifdef PNG_USER_LIMITS_SUPPORTED
2912 switch (png_ptr
->user_chunk_cache_max
)
2915 png_ptr
->user_chunk_cache_max
= 1;
2916 png_chunk_benign_error(png_ptr
, "no space in chunk cache");
2919 /* NOTE: prior to 1.6.0 this case resulted in an unknown critical
2920 * chunk being skipped, now there will be a hard error below.
2924 default: /* not at limit */
2925 --(png_ptr
->user_chunk_cache_max
);
2927 case 0: /* no limit */
2928 # endif /* PNG_USER_LIMITS_SUPPORTED */
2929 /* Here when the limit isn't reached or when limits are compiled
2930 * out; store the chunk.
2932 png_set_unknown_chunks(png_ptr
, info_ptr
,
2933 &png_ptr
->unknown_chunk
, 1);
2935 # ifdef PNG_USER_LIMITS_SUPPORTED
2940 # else /* no store support: the chunk must be handled by the user callback */
2941 PNG_UNUSED(info_ptr
)
2944 /* Regardless of the error handling below the cached data (if any) can be
2945 * freed now. Notice that the data is not freed if there is a png_error, but
2946 * it will be freed by destroy_read_struct.
2948 if (png_ptr
->unknown_chunk
.data
!= NULL
)
2949 png_free(png_ptr
, png_ptr
->unknown_chunk
.data
);
2950 png_ptr
->unknown_chunk
.data
= NULL
;
2952 #else /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */
2953 /* There is no support to read an unknown chunk, so just skip it. */
2954 png_crc_finish(png_ptr
, length
);
2955 PNG_UNUSED(info_ptr
)
2957 #endif /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */
2959 /* Check for unhandled critical chunks */
2960 if (!handled
&& PNG_CHUNK_CRITICAL(png_ptr
->chunk_name
))
2961 png_chunk_error(png_ptr
, "unhandled critical chunk");
2964 /* This function is called to verify that a chunk name is valid.
2965 * This function can't have the "critical chunk check" incorporated
2966 * into it, since in the future we will need to be able to call user
2967 * functions to handle unknown critical chunks after we check that
2968 * the chunk name itself is valid.
2971 /* Bit hacking: the test for an invalid byte in the 4 byte chunk name is:
2973 * ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
2977 png_check_chunk_name(png_structrp png_ptr
, png_uint_32 chunk_name
)
2981 png_debug(1, "in png_check_chunk_name");
2983 for (i
=1; i
<=4; ++i
)
2985 int c
= chunk_name
& 0xff;
2987 if (c
< 65 || c
> 122 || (c
> 90 && c
< 97))
2988 png_chunk_error(png_ptr
, "invalid chunk type");
2994 /* Combines the row recently read in with the existing pixels in the row. This
2995 * routine takes care of alpha and transparency if requested. This routine also
2996 * handles the two methods of progressive display of interlaced images,
2997 * depending on the 'display' value; if 'display' is true then the whole row
2998 * (dp) is filled from the start by replicating the available pixels. If
2999 * 'display' is false only those pixels present in the pass are filled in.
3002 png_combine_row(png_const_structrp png_ptr
, png_bytep dp
, int display
)
3004 unsigned int pixel_depth
= png_ptr
->transformed_pixel_depth
;
3005 png_const_bytep sp
= png_ptr
->row_buf
+ 1;
3006 png_uint_32 row_width
= png_ptr
->width
;
3007 unsigned int pass
= png_ptr
->pass
;
3008 png_bytep end_ptr
= 0;
3009 png_byte end_byte
= 0;
3010 unsigned int end_mask
;
3012 png_debug(1, "in png_combine_row");
3014 /* Added in 1.5.6: it should not be possible to enter this routine until at
3015 * least one row has been read from the PNG data and transformed.
3017 if (pixel_depth
== 0)
3018 png_error(png_ptr
, "internal row logic error");
3020 /* Added in 1.5.4: the pixel depth should match the information returned by
3021 * any call to png_read_update_info at this point. Do not continue if we got
3024 if (png_ptr
->info_rowbytes
!= 0 && png_ptr
->info_rowbytes
!=
3025 PNG_ROWBYTES(pixel_depth
, row_width
))
3026 png_error(png_ptr
, "internal row size calculation error");
3028 /* Don't expect this to ever happen: */
3030 png_error(png_ptr
, "internal row width error");
3032 /* Preserve the last byte in cases where only part of it will be overwritten,
3033 * the multiply below may overflow, we don't care because ANSI-C guarantees
3034 * we get the low bits.
3036 end_mask
= (pixel_depth
* row_width
) & 7;
3039 /* end_ptr == NULL is a flag to say do nothing */
3040 end_ptr
= dp
+ PNG_ROWBYTES(pixel_depth
, row_width
) - 1;
3041 end_byte
= *end_ptr
;
3042 # ifdef PNG_READ_PACKSWAP_SUPPORTED
3043 if (png_ptr
->transformations
& PNG_PACKSWAP
) /* little-endian byte */
3044 end_mask
= 0xff << end_mask
;
3046 else /* big-endian byte */
3048 end_mask
= 0xff >> end_mask
;
3049 /* end_mask is now the bits to *keep* from the destination row */
3052 /* For non-interlaced images this reduces to a memcpy(). A memcpy()
3053 * will also happen if interlacing isn't supported or if the application
3054 * does not call png_set_interlace_handling(). In the latter cases the
3055 * caller just gets a sequence of the unexpanded rows from each interlace
3058 #ifdef PNG_READ_INTERLACING_SUPPORTED
3059 if (png_ptr
->interlaced
&& (png_ptr
->transformations
& PNG_INTERLACE
) &&
3060 pass
< 6 && (display
== 0 ||
3061 /* The following copies everything for 'display' on passes 0, 2 and 4. */
3062 (display
== 1 && (pass
& 1) != 0)))
3064 /* Narrow images may have no bits in a pass; the caller should handle
3065 * this, but this test is cheap:
3067 if (row_width
<= PNG_PASS_START_COL(pass
))
3070 if (pixel_depth
< 8)
3072 /* For pixel depths up to 4 bpp the 8-pixel mask can be expanded to fit
3073 * into 32 bits, then a single loop over the bytes using the four byte
3074 * values in the 32-bit mask can be used. For the 'display' option the
3075 * expanded mask may also not require any masking within a byte. To
3076 * make this work the PACKSWAP option must be taken into account - it
3077 * simply requires the pixels to be reversed in each byte.
3079 * The 'regular' case requires a mask for each of the first 6 passes,
3080 * the 'display' case does a copy for the even passes in the range
3081 * 0..6. This has already been handled in the test above.
3083 * The masks are arranged as four bytes with the first byte to use in
3084 * the lowest bits (little-endian) regardless of the order (PACKSWAP or
3085 * not) of the pixels in each byte.
3087 * NOTE: the whole of this logic depends on the caller of this function
3088 * only calling it on rows appropriate to the pass. This function only
3089 * understands the 'x' logic; the 'y' logic is handled by the caller.
3091 * The following defines allow generation of compile time constant bit
3092 * masks for each pixel depth and each possibility of swapped or not
3093 * swapped bytes. Pass 'p' is in the range 0..6; 'x', a pixel index,
3094 * is in the range 0..7; and the result is 1 if the pixel is to be
3095 * copied in the pass, 0 if not. 'S' is for the sparkle method, 'B'
3096 * for the block method.
3098 * With some compilers a compile time expression of the general form:
3100 * (shift >= 32) ? (a >> (shift-32)) : (b >> shift)
3102 * Produces warnings with values of 'shift' in the range 33 to 63
3103 * because the right hand side of the ?: expression is evaluated by
3104 * the compiler even though it isn't used. Microsoft Visual C (various
3105 * versions) and the Intel C compiler are known to do this. To avoid
3106 * this the following macros are used in 1.5.6. This is a temporary
3107 * solution to avoid destabilizing the code during the release process.
3109 # if PNG_USE_COMPILE_TIME_MASKS
3110 # define PNG_LSR(x,s) ((x)>>((s) & 0x1f))
3111 # define PNG_LSL(x,s) ((x)<<((s) & 0x1f))
3113 # define PNG_LSR(x,s) ((x)>>(s))
3114 # define PNG_LSL(x,s) ((x)<<(s))
3116 # define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\
3117 PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1)
3118 # define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\
3119 PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1)
3121 /* Return a mask for pass 'p' pixel 'x' at depth 'd'. The mask is
3122 * little endian - the first pixel is at bit 0 - however the extra
3123 * parameter 's' can be set to cause the mask position to be swapped
3124 * within each byte, to match the PNG format. This is done by XOR of
3125 * the shift with 7, 6 or 4 for bit depths 1, 2 and 4.
3127 # define PIXEL_MASK(p,x,d,s) \
3128 (PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0))))
3130 /* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask.
3132 # define S_MASKx(p,x,d,s) (S_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
3133 # define B_MASKx(p,x,d,s) (B_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
3135 /* Combine 8 of these to get the full mask. For the 1-bpp and 2-bpp
3136 * cases the result needs replicating, for the 4-bpp case the above
3137 * generates a full 32 bits.
3139 # define MASK_EXPAND(m,d) ((m)*((d)==1?0x01010101:((d)==2?0x00010001:1)))
3141 # define S_MASK(p,d,s) MASK_EXPAND(S_MASKx(p,0,d,s) + S_MASKx(p,1,d,s) +\
3142 S_MASKx(p,2,d,s) + S_MASKx(p,3,d,s) + S_MASKx(p,4,d,s) +\
3143 S_MASKx(p,5,d,s) + S_MASKx(p,6,d,s) + S_MASKx(p,7,d,s), d)
3145 # define B_MASK(p,d,s) MASK_EXPAND(B_MASKx(p,0,d,s) + B_MASKx(p,1,d,s) +\
3146 B_MASKx(p,2,d,s) + B_MASKx(p,3,d,s) + B_MASKx(p,4,d,s) +\
3147 B_MASKx(p,5,d,s) + B_MASKx(p,6,d,s) + B_MASKx(p,7,d,s), d)
3149 #if PNG_USE_COMPILE_TIME_MASKS
3150 /* Utility macros to construct all the masks for a depth/swap
3151 * combination. The 's' parameter says whether the format is PNG
3152 * (big endian bytes) or not. Only the three odd-numbered passes are
3153 * required for the display/block algorithm.
3155 # define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\
3156 S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) }
3158 # define B_MASKS(d,s) { B_MASK(1,d,s), S_MASK(3,d,s), S_MASK(5,d,s) }
3160 # define DEPTH_INDEX(d) ((d)==1?0:((d)==2?1:2))
3162 /* Hence the pre-compiled masks indexed by PACKSWAP (or not), depth and
3165 static PNG_CONST png_uint_32 row_mask
[2/*PACKSWAP*/][3/*depth*/][6] =
3167 /* Little-endian byte masks for PACKSWAP */
3168 { S_MASKS(1,0), S_MASKS(2,0), S_MASKS(4,0) },
3169 /* Normal (big-endian byte) masks - PNG format */
3170 { S_MASKS(1,1), S_MASKS(2,1), S_MASKS(4,1) }
3173 /* display_mask has only three entries for the odd passes, so index by
3176 static PNG_CONST png_uint_32 display_mask
[2][3][3] =
3178 /* Little-endian byte masks for PACKSWAP */
3179 { B_MASKS(1,0), B_MASKS(2,0), B_MASKS(4,0) },
3180 /* Normal (big-endian byte) masks - PNG format */
3181 { B_MASKS(1,1), B_MASKS(2,1), B_MASKS(4,1) }
3184 # define MASK(pass,depth,display,png)\
3185 ((display)?display_mask[png][DEPTH_INDEX(depth)][pass>>1]:\
3186 row_mask[png][DEPTH_INDEX(depth)][pass])
3188 #else /* !PNG_USE_COMPILE_TIME_MASKS */
3189 /* This is the runtime alternative: it seems unlikely that this will
3190 * ever be either smaller or faster than the compile time approach.
3192 # define MASK(pass,depth,display,png)\
3193 ((display)?B_MASK(pass,depth,png):S_MASK(pass,depth,png))
3194 #endif /* !PNG_USE_COMPILE_TIME_MASKS */
3196 /* Use the appropriate mask to copy the required bits. In some cases
3197 * the byte mask will be 0 or 0xff, optimize these cases. row_width is
3198 * the number of pixels, but the code copies bytes, so it is necessary
3199 * to special case the end.
3201 png_uint_32 pixels_per_byte
= 8 / pixel_depth
;
3204 # ifdef PNG_READ_PACKSWAP_SUPPORTED
3205 if (png_ptr
->transformations
& PNG_PACKSWAP
)
3206 mask
= MASK(pass
, pixel_depth
, display
, 0);
3210 mask
= MASK(pass
, pixel_depth
, display
, 1);
3216 /* It doesn't matter in the following if png_uint_32 has more than
3217 * 32 bits because the high bits always match those in m<<24; it is,
3218 * however, essential to use OR here, not +, because of this.
3221 mask
= (m
>> 8) | (m
<< 24); /* rotate right to good compilers */
3224 if (m
!= 0) /* something to copy */
3227 *dp
= (png_byte
)((*dp
& ~m
) | (*sp
& m
));
3232 /* NOTE: this may overwrite the last byte with garbage if the image
3233 * is not an exact number of bytes wide; libpng has always done
3236 if (row_width
<= pixels_per_byte
)
3237 break; /* May need to restore part of the last byte */
3239 row_width
-= pixels_per_byte
;
3245 else /* pixel_depth >= 8 */
3247 unsigned int bytes_to_copy
, bytes_to_jump
;
3249 /* Validate the depth - it must be a multiple of 8 */
3250 if (pixel_depth
& 7)
3251 png_error(png_ptr
, "invalid user transform pixel depth");
3253 pixel_depth
>>= 3; /* now in bytes */
3254 row_width
*= pixel_depth
;
3256 /* Regardless of pass number the Adam 7 interlace always results in a
3257 * fixed number of pixels to copy then to skip. There may be a
3258 * different number of pixels to skip at the start though.
3261 unsigned int offset
= PNG_PASS_START_COL(pass
) * pixel_depth
;
3263 row_width
-= offset
;
3268 /* Work out the bytes to copy. */
3271 /* When doing the 'block' algorithm the pixel in the pass gets
3272 * replicated to adjacent pixels. This is why the even (0,2,4,6)
3273 * passes are skipped above - the entire expanded row is copied.
3275 bytes_to_copy
= (1<<((6-pass
)>>1)) * pixel_depth
;
3277 /* But don't allow this number to exceed the actual row width. */
3278 if (bytes_to_copy
> row_width
)
3279 bytes_to_copy
= row_width
;
3282 else /* normal row; Adam7 only ever gives us one pixel to copy. */
3283 bytes_to_copy
= pixel_depth
;
3285 /* In Adam7 there is a constant offset between where the pixels go. */
3286 bytes_to_jump
= PNG_PASS_COL_OFFSET(pass
) * pixel_depth
;
3288 /* And simply copy these bytes. Some optimization is possible here,
3289 * depending on the value of 'bytes_to_copy'. Special case the low
3290 * byte counts, which we know to be frequent.
3292 * Notice that these cases all 'return' rather than 'break' - this
3293 * avoids an unnecessary test on whether to restore the last byte
3296 switch (bytes_to_copy
)
3303 if (row_width
<= bytes_to_jump
)
3306 dp
+= bytes_to_jump
;
3307 sp
+= bytes_to_jump
;
3308 row_width
-= bytes_to_jump
;
3312 /* There is a possibility of a partial copy at the end here; this
3313 * slows the code down somewhat.
3317 dp
[0] = sp
[0], dp
[1] = sp
[1];
3319 if (row_width
<= bytes_to_jump
)
3322 sp
+= bytes_to_jump
;
3323 dp
+= bytes_to_jump
;
3324 row_width
-= bytes_to_jump
;
3326 while (row_width
> 1);
3328 /* And there can only be one byte left at this point: */
3333 /* This can only be the RGB case, so each copy is exactly one
3334 * pixel and it is not necessary to check for a partial copy.
3338 dp
[0] = sp
[0], dp
[1] = sp
[1], dp
[2] = sp
[2];
3340 if (row_width
<= bytes_to_jump
)
3343 sp
+= bytes_to_jump
;
3344 dp
+= bytes_to_jump
;
3345 row_width
-= bytes_to_jump
;
3349 #if PNG_ALIGN_TYPE != PNG_ALIGN_NONE
3350 /* Check for double byte alignment and, if possible, use a
3351 * 16-bit copy. Don't attempt this for narrow images - ones that
3352 * are less than an interlace panel wide. Don't attempt it for
3353 * wide bytes_to_copy either - use the memcpy there.
3355 if (bytes_to_copy
< 16 /*else use memcpy*/ &&
3356 png_isaligned(dp
, png_uint_16
) &&
3357 png_isaligned(sp
, png_uint_16
) &&
3358 bytes_to_copy
% (sizeof (png_uint_16
)) == 0 &&
3359 bytes_to_jump
% (sizeof (png_uint_16
)) == 0)
3361 /* Everything is aligned for png_uint_16 copies, but try for
3362 * png_uint_32 first.
3364 if (png_isaligned(dp
, png_uint_32
) &&
3365 png_isaligned(sp
, png_uint_32
) &&
3366 bytes_to_copy
% (sizeof (png_uint_32
)) == 0 &&
3367 bytes_to_jump
% (sizeof (png_uint_32
)) == 0)
3369 png_uint_32p dp32
= png_aligncast(png_uint_32p
,dp
);
3370 png_const_uint_32p sp32
= png_aligncastconst(
3371 png_const_uint_32p
, sp
);
3372 size_t skip
= (bytes_to_jump
-bytes_to_copy
) /
3373 (sizeof (png_uint_32
));
3377 size_t c
= bytes_to_copy
;
3381 c
-= (sizeof (png_uint_32
));
3385 if (row_width
<= bytes_to_jump
)
3390 row_width
-= bytes_to_jump
;
3392 while (bytes_to_copy
<= row_width
);
3394 /* Get to here when the row_width truncates the final copy.
3395 * There will be 1-3 bytes left to copy, so don't try the
3396 * 16-bit loop below.
3398 dp
= (png_bytep
)dp32
;
3399 sp
= (png_const_bytep
)sp32
;
3402 while (--row_width
> 0);
3406 /* Else do it in 16-bit quantities, but only if the size is
3411 png_uint_16p dp16
= png_aligncast(png_uint_16p
, dp
);
3412 png_const_uint_16p sp16
= png_aligncastconst(
3413 png_const_uint_16p
, sp
);
3414 size_t skip
= (bytes_to_jump
-bytes_to_copy
) /
3415 (sizeof (png_uint_16
));
3419 size_t c
= bytes_to_copy
;
3423 c
-= (sizeof (png_uint_16
));
3427 if (row_width
<= bytes_to_jump
)
3432 row_width
-= bytes_to_jump
;
3434 while (bytes_to_copy
<= row_width
);
3436 /* End of row - 1 byte left, bytes_to_copy > row_width: */
3437 dp
= (png_bytep
)dp16
;
3438 sp
= (png_const_bytep
)sp16
;
3441 while (--row_width
> 0);
3445 #endif /* PNG_ALIGN_ code */
3447 /* The true default - use a memcpy: */
3450 memcpy(dp
, sp
, bytes_to_copy
);
3452 if (row_width
<= bytes_to_jump
)
3455 sp
+= bytes_to_jump
;
3456 dp
+= bytes_to_jump
;
3457 row_width
-= bytes_to_jump
;
3458 if (bytes_to_copy
> row_width
)
3459 bytes_to_copy
= row_width
;
3464 } /* pixel_depth >= 8 */
3466 /* Here if pixel_depth < 8 to check 'end_ptr' below. */
3471 /* If here then the switch above wasn't used so just memcpy the whole row
3472 * from the temporary row buffer (notice that this overwrites the end of the
3473 * destination row if it is a partial byte.)
3475 memcpy(dp
, sp
, PNG_ROWBYTES(pixel_depth
, row_width
));
3477 /* Restore the overwritten bits from the last byte if necessary. */
3478 if (end_ptr
!= NULL
)
3479 *end_ptr
= (png_byte
)((end_byte
& end_mask
) | (*end_ptr
& ~end_mask
));
3482 #ifdef PNG_READ_INTERLACING_SUPPORTED
3484 png_do_read_interlace(png_row_infop row_info
, png_bytep row
, int pass
,
3485 png_uint_32 transformations
/* Because these may affect the byte layout */)
3487 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
3488 /* Offset to next interlace block */
3489 static PNG_CONST
int png_pass_inc
[7] = {8, 8, 4, 4, 2, 2, 1};
3491 png_debug(1, "in png_do_read_interlace");
3492 if (row
!= NULL
&& row_info
!= NULL
)
3494 png_uint_32 final_width
;
3496 final_width
= row_info
->width
* png_pass_inc
[pass
];
3498 switch (row_info
->pixel_depth
)
3502 png_bytep sp
= row
+ (png_size_t
)((row_info
->width
- 1) >> 3);
3503 png_bytep dp
= row
+ (png_size_t
)((final_width
- 1) >> 3);
3505 int s_start
, s_end
, s_inc
;
3506 int jstop
= png_pass_inc
[pass
];
3511 #ifdef PNG_READ_PACKSWAP_SUPPORTED
3512 if (transformations
& PNG_PACKSWAP
)
3514 sshift
= (int)((row_info
->width
+ 7) & 0x07);
3515 dshift
= (int)((final_width
+ 7) & 0x07);
3524 sshift
= 7 - (int)((row_info
->width
+ 7) & 0x07);
3525 dshift
= 7 - (int)((final_width
+ 7) & 0x07);
3531 for (i
= 0; i
< row_info
->width
; i
++)
3533 v
= (png_byte
)((*sp
>> sshift
) & 0x01);
3534 for (j
= 0; j
< jstop
; j
++)
3536 unsigned int tmp
= *dp
& (0x7f7f >> (7 - dshift
));
3538 *dp
= (png_byte
)(tmp
& 0xff);
3540 if (dshift
== s_end
)
3550 if (sshift
== s_end
)
3564 png_bytep sp
= row
+ (png_uint_32
)((row_info
->width
- 1) >> 2);
3565 png_bytep dp
= row
+ (png_uint_32
)((final_width
- 1) >> 2);
3567 int s_start
, s_end
, s_inc
;
3568 int jstop
= png_pass_inc
[pass
];
3571 #ifdef PNG_READ_PACKSWAP_SUPPORTED
3572 if (transformations
& PNG_PACKSWAP
)
3574 sshift
= (int)(((row_info
->width
+ 3) & 0x03) << 1);
3575 dshift
= (int)(((final_width
+ 3) & 0x03) << 1);
3584 sshift
= (int)((3 - ((row_info
->width
+ 3) & 0x03)) << 1);
3585 dshift
= (int)((3 - ((final_width
+ 3) & 0x03)) << 1);
3591 for (i
= 0; i
< row_info
->width
; i
++)
3596 v
= (png_byte
)((*sp
>> sshift
) & 0x03);
3597 for (j
= 0; j
< jstop
; j
++)
3599 unsigned int tmp
= *dp
& (0x3f3f >> (6 - dshift
));
3601 *dp
= (png_byte
)(tmp
& 0xff);
3603 if (dshift
== s_end
)
3613 if (sshift
== s_end
)
3627 png_bytep sp
= row
+ (png_size_t
)((row_info
->width
- 1) >> 1);
3628 png_bytep dp
= row
+ (png_size_t
)((final_width
- 1) >> 1);
3630 int s_start
, s_end
, s_inc
;
3632 int jstop
= png_pass_inc
[pass
];
3634 #ifdef PNG_READ_PACKSWAP_SUPPORTED
3635 if (transformations
& PNG_PACKSWAP
)
3637 sshift
= (int)(((row_info
->width
+ 1) & 0x01) << 2);
3638 dshift
= (int)(((final_width
+ 1) & 0x01) << 2);
3647 sshift
= (int)((1 - ((row_info
->width
+ 1) & 0x01)) << 2);
3648 dshift
= (int)((1 - ((final_width
+ 1) & 0x01)) << 2);
3654 for (i
= 0; i
< row_info
->width
; i
++)
3656 png_byte v
= (png_byte
)((*sp
>> sshift
) & 0x0f);
3659 for (j
= 0; j
< jstop
; j
++)
3661 unsigned int tmp
= *dp
& (0xf0f >> (4 - dshift
));
3663 *dp
= (png_byte
)(tmp
& 0xff);
3665 if (dshift
== s_end
)
3675 if (sshift
== s_end
)
3689 png_size_t pixel_bytes
= (row_info
->pixel_depth
>> 3);
3691 png_bytep sp
= row
+ (png_size_t
)(row_info
->width
- 1)
3694 png_bytep dp
= row
+ (png_size_t
)(final_width
- 1) * pixel_bytes
;
3696 int jstop
= png_pass_inc
[pass
];
3699 for (i
= 0; i
< row_info
->width
; i
++)
3701 png_byte v
[8]; /* SAFE; pixel_depth does not exceed 64 */
3704 memcpy(v
, sp
, pixel_bytes
);
3706 for (j
= 0; j
< jstop
; j
++)
3708 memcpy(dp
, v
, pixel_bytes
);
3718 row_info
->width
= final_width
;
3719 row_info
->rowbytes
= PNG_ROWBYTES(row_info
->pixel_depth
, final_width
);
3721 #ifndef PNG_READ_PACKSWAP_SUPPORTED
3722 PNG_UNUSED(transformations
) /* Silence compiler warning */
3725 #endif /* PNG_READ_INTERLACING_SUPPORTED */
3728 png_read_filter_row_sub(png_row_infop row_info
, png_bytep row
,
3729 png_const_bytep prev_row
)
3732 png_size_t istop
= row_info
->rowbytes
;
3733 unsigned int bpp
= (row_info
->pixel_depth
+ 7) >> 3;
3734 png_bytep rp
= row
+ bpp
;
3736 PNG_UNUSED(prev_row
)
3738 for (i
= bpp
; i
< istop
; i
++)
3740 *rp
= (png_byte
)(((int)(*rp
) + (int)(*(rp
-bpp
))) & 0xff);
3746 png_read_filter_row_up(png_row_infop row_info
, png_bytep row
,
3747 png_const_bytep prev_row
)
3750 png_size_t istop
= row_info
->rowbytes
;
3752 png_const_bytep pp
= prev_row
;
3754 for (i
= 0; i
< istop
; i
++)
3756 *rp
= (png_byte
)(((int)(*rp
) + (int)(*pp
++)) & 0xff);
3762 png_read_filter_row_avg(png_row_infop row_info
, png_bytep row
,
3763 png_const_bytep prev_row
)
3767 png_const_bytep pp
= prev_row
;
3768 unsigned int bpp
= (row_info
->pixel_depth
+ 7) >> 3;
3769 png_size_t istop
= row_info
->rowbytes
- bpp
;
3771 for (i
= 0; i
< bpp
; i
++)
3773 *rp
= (png_byte
)(((int)(*rp
) +
3774 ((int)(*pp
++) / 2 )) & 0xff);
3779 for (i
= 0; i
< istop
; i
++)
3781 *rp
= (png_byte
)(((int)(*rp
) +
3782 (int)(*pp
++ + *(rp
-bpp
)) / 2 ) & 0xff);
3789 png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info
, png_bytep row
,
3790 png_const_bytep prev_row
)
3792 png_bytep rp_end
= row
+ row_info
->rowbytes
;
3795 /* First pixel/byte */
3798 *row
++ = (png_byte
)a
;
3801 while (row
< rp_end
)
3803 int b
, pa
, pb
, pc
, p
;
3805 a
&= 0xff; /* From previous iteration or start */
3816 pa
= p
< 0 ?
-p
: p
;
3817 pb
= pc
< 0 ?
-pc
: pc
;
3818 pc
= (p
+ pc
) < 0 ?
-(p
+ pc
) : p
+ pc
;
3821 /* Find the best predictor, the least of pa, pb, pc favoring the earlier
3822 * ones in the case of a tie.
3824 if (pb
< pa
) pa
= pb
, a
= b
;
3827 /* Calculate the current pixel in a, and move the previous row pixel to c
3828 * for the next time round the loop
3832 *row
++ = (png_byte
)a
;
3837 png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info
, png_bytep row
,
3838 png_const_bytep prev_row
)
3840 int bpp
= (row_info
->pixel_depth
+ 7) >> 3;
3841 png_bytep rp_end
= row
+ bpp
;
3843 /* Process the first pixel in the row completely (this is the same as 'up'
3844 * because there is only one candidate predictor for the first row).
3846 while (row
< rp_end
)
3848 int a
= *row
+ *prev_row
++;
3849 *row
++ = (png_byte
)a
;
3853 rp_end
+= row_info
->rowbytes
- bpp
;
3855 while (row
< rp_end
)
3857 int a
, b
, c
, pa
, pb
, pc
, p
;
3859 c
= *(prev_row
- bpp
);
3871 pa
= p
< 0 ?
-p
: p
;
3872 pb
= pc
< 0 ?
-pc
: pc
;
3873 pc
= (p
+ pc
) < 0 ?
-(p
+ pc
) : p
+ pc
;
3876 if (pb
< pa
) pa
= pb
, a
= b
;
3880 *row
++ = (png_byte
)a
;
3885 png_init_filter_functions(png_structrp pp
)
3886 /* This function is called once for every PNG image (except for PNG images
3887 * that only use PNG_FILTER_VALUE_NONE for all rows) to set the
3888 * implementations required to reverse the filtering of PNG rows. Reversing
3889 * the filter is the first transformation performed on the row data. It is
3890 * performed in place, therefore an implementation can be selected based on
3891 * the image pixel format. If the implementation depends on image width then
3892 * take care to ensure that it works correctly if the image is interlaced -
3893 * interlacing causes the actual row width to vary.
3896 unsigned int bpp
= (pp
->pixel_depth
+ 7) >> 3;
3898 pp
->read_filter
[PNG_FILTER_VALUE_SUB
-1] = png_read_filter_row_sub
;
3899 pp
->read_filter
[PNG_FILTER_VALUE_UP
-1] = png_read_filter_row_up
;
3900 pp
->read_filter
[PNG_FILTER_VALUE_AVG
-1] = png_read_filter_row_avg
;
3902 pp
->read_filter
[PNG_FILTER_VALUE_PAETH
-1] =
3903 png_read_filter_row_paeth_1byte_pixel
;
3905 pp
->read_filter
[PNG_FILTER_VALUE_PAETH
-1] =
3906 png_read_filter_row_paeth_multibyte_pixel
;
3908 #ifdef PNG_FILTER_OPTIMIZATIONS
3909 /* To use this define PNG_FILTER_OPTIMIZATIONS as the name of a function to
3910 * call to install hardware optimizations for the above functions; simply
3911 * replace whatever elements of the pp->read_filter[] array with a hardware
3912 * specific (or, for that matter, generic) optimization.
3914 * To see an example of this examine what configure.ac does when
3915 * --enable-arm-neon is specified on the command line.
3917 PNG_FILTER_OPTIMIZATIONS(pp
, bpp
);
3922 png_read_filter_row(png_structrp pp
, png_row_infop row_info
, png_bytep row
,
3923 png_const_bytep prev_row
, int filter
)
3925 /* OPTIMIZATION: DO NOT MODIFY THIS FUNCTION, instead #define
3926 * PNG_FILTER_OPTIMIZATIONS to a function that overrides the generic
3927 * implementations. See png_init_filter_functions above.
3929 if (filter
> PNG_FILTER_VALUE_NONE
&& filter
< PNG_FILTER_VALUE_LAST
)
3931 if (pp
->read_filter
[0] == NULL
)
3932 png_init_filter_functions(pp
);
3934 pp
->read_filter
[filter
-1](row_info
, row
, prev_row
);
3938 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
3940 png_read_IDAT_data(png_structrp png_ptr
, png_bytep output
,
3941 png_alloc_size_t avail_out
)
3943 /* Loop reading IDATs and decompressing the result into output[avail_out] */
3944 png_ptr
->zstream
.next_out
= output
;
3945 png_ptr
->zstream
.avail_out
= 0; /* safety: set below */
3953 png_byte tmpbuf
[PNG_INFLATE_BUF_SIZE
];
3955 if (png_ptr
->zstream
.avail_in
== 0)
3960 while (png_ptr
->idat_size
== 0)
3962 png_crc_finish(png_ptr
, 0);
3964 png_ptr
->idat_size
= png_read_chunk_header(png_ptr
);
3965 /* This is an error even in the 'check' case because the code just
3966 * consumed a non-IDAT header.
3968 if (png_ptr
->chunk_name
!= png_IDAT
)
3969 png_error(png_ptr
, "Not enough image data");
3972 avail_in
= png_ptr
->IDAT_read_size
;
3974 if (avail_in
> png_ptr
->idat_size
)
3975 avail_in
= (uInt
)png_ptr
->idat_size
;
3977 /* A PNG with a gradually increasing IDAT size will defeat this attempt
3978 * to minimize memory usage by causing lots of re-allocs, but
3979 * realistically doing IDAT_read_size re-allocs is not likely to be a
3982 buffer
= png_read_buffer(png_ptr
, avail_in
, 0/*error*/);
3984 png_crc_read(png_ptr
, buffer
, avail_in
);
3985 png_ptr
->idat_size
-= avail_in
;
3987 png_ptr
->zstream
.next_in
= buffer
;
3988 png_ptr
->zstream
.avail_in
= avail_in
;
3991 /* And set up the output side. */
3992 if (output
!= NULL
) /* standard read */
3994 uInt out
= ZLIB_IO_MAX
;
3996 if (out
> avail_out
)
3997 out
= (uInt
)avail_out
;
4000 png_ptr
->zstream
.avail_out
= out
;
4003 else /* after last row, checking for end */
4005 png_ptr
->zstream
.next_out
= tmpbuf
;
4006 png_ptr
->zstream
.avail_out
= (sizeof tmpbuf
);
4009 /* Use NO_FLUSH; this gives zlib the maximum opportunity to optimize the
4010 * process. If the LZ stream is truncated the sequential reader will
4011 * terminally damage the stream, above, by reading the chunk header of the
4012 * following chunk (it then exits with png_error).
4014 * TODO: deal more elegantly with truncated IDAT lists.
4016 ret
= inflate(&png_ptr
->zstream
, Z_NO_FLUSH
);
4018 /* Take the unconsumed output back. */
4020 avail_out
+= png_ptr
->zstream
.avail_out
;
4022 else /* avail_out counts the extra bytes */
4023 avail_out
+= (sizeof tmpbuf
) - png_ptr
->zstream
.avail_out
;
4025 png_ptr
->zstream
.avail_out
= 0;
4027 if (ret
== Z_STREAM_END
)
4029 /* Do this for safety; we won't read any more into this row. */
4030 png_ptr
->zstream
.next_out
= NULL
;
4032 png_ptr
->mode
|= PNG_AFTER_IDAT
;
4033 png_ptr
->flags
|= PNG_FLAG_ZSTREAM_ENDED
;
4035 if (png_ptr
->zstream
.avail_in
> 0 || png_ptr
->idat_size
> 0)
4036 png_chunk_benign_error(png_ptr
, "Extra compressed data");
4042 png_zstream_error(png_ptr
, ret
);
4045 png_chunk_error(png_ptr
, png_ptr
->zstream
.msg
);
4049 png_chunk_benign_error(png_ptr
, png_ptr
->zstream
.msg
);
4053 } while (avail_out
> 0);
4057 /* The stream ended before the image; this is the same as too few IDATs so
4058 * should be handled the same way.
4061 png_error(png_ptr
, "Not enough image data");
4063 else /* the deflate stream contained extra data */
4064 png_chunk_benign_error(png_ptr
, "Too much image data");
4069 png_read_finish_IDAT(png_structrp png_ptr
)
4071 /* We don't need any more data and the stream should have ended, however the
4072 * LZ end code may actually not have been processed. In this case we must
4073 * read it otherwise stray unread IDAT data or, more likely, an IDAT chunk
4074 * may still remain to be consumed.
4076 if (!(png_ptr
->flags
& PNG_FLAG_ZSTREAM_ENDED
))
4078 /* The NULL causes png_read_IDAT_data to swallow any remaining bytes in
4079 * the compressed stream, but the stream may be damaged too, so even after
4080 * this call we may need to terminate the zstream ownership.
4082 png_read_IDAT_data(png_ptr
, NULL
, 0);
4083 png_ptr
->zstream
.next_out
= NULL
; /* safety */
4085 /* Now clear everything out for safety; the following may not have been
4088 if (!(png_ptr
->flags
& PNG_FLAG_ZSTREAM_ENDED
))
4090 png_ptr
->mode
|= PNG_AFTER_IDAT
;
4091 png_ptr
->flags
|= PNG_FLAG_ZSTREAM_ENDED
;
4095 /* If the zstream has not been released do it now *and* terminate the reading
4096 * of the final IDAT chunk.
4098 if (png_ptr
->zowner
== png_IDAT
)
4100 /* Always do this; the pointers otherwise point into the read buffer. */
4101 png_ptr
->zstream
.next_in
= NULL
;
4102 png_ptr
->zstream
.avail_in
= 0;
4104 /* Now we no longer own the zstream. */
4105 png_ptr
->zowner
= 0;
4107 /* The slightly weird semantics of the sequential IDAT reading is that we
4108 * are always in or at the end of an IDAT chunk, so we always need to do a
4109 * crc_finish here. If idat_size is non-zero we also need to read the
4110 * spurious bytes at the end of the chunk now.
4112 (void)png_crc_finish(png_ptr
, png_ptr
->idat_size
);
4117 png_read_finish_row(png_structrp png_ptr
)
4119 #ifdef PNG_READ_INTERLACING_SUPPORTED
4120 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
4122 /* Start of interlace block */
4123 static PNG_CONST png_byte png_pass_start
[7] = {0, 4, 0, 2, 0, 1, 0};
4125 /* Offset to next interlace block */
4126 static PNG_CONST png_byte png_pass_inc
[7] = {8, 8, 4, 4, 2, 2, 1};
4128 /* Start of interlace block in the y direction */
4129 static PNG_CONST png_byte png_pass_ystart
[7] = {0, 0, 4, 0, 2, 0, 1};
4131 /* Offset to next interlace block in the y direction */
4132 static PNG_CONST png_byte png_pass_yinc
[7] = {8, 8, 8, 4, 4, 2, 2};
4133 #endif /* PNG_READ_INTERLACING_SUPPORTED */
4135 png_debug(1, "in png_read_finish_row");
4136 png_ptr
->row_number
++;
4137 if (png_ptr
->row_number
< png_ptr
->num_rows
)
4140 #ifdef PNG_READ_INTERLACING_SUPPORTED
4141 if (png_ptr
->interlaced
)
4143 png_ptr
->row_number
= 0;
4145 /* TO DO: don't do this if prev_row isn't needed (requires
4146 * read-ahead of the next row's filter byte.
4148 memset(png_ptr
->prev_row
, 0, png_ptr
->rowbytes
+ 1);
4154 if (png_ptr
->pass
>= 7)
4157 png_ptr
->iwidth
= (png_ptr
->width
+
4158 png_pass_inc
[png_ptr
->pass
] - 1 -
4159 png_pass_start
[png_ptr
->pass
]) /
4160 png_pass_inc
[png_ptr
->pass
];
4162 if (!(png_ptr
->transformations
& PNG_INTERLACE
))
4164 png_ptr
->num_rows
= (png_ptr
->height
+
4165 png_pass_yinc
[png_ptr
->pass
] - 1 -
4166 png_pass_ystart
[png_ptr
->pass
]) /
4167 png_pass_yinc
[png_ptr
->pass
];
4170 else /* if (png_ptr->transformations & PNG_INTERLACE) */
4171 break; /* libpng deinterlacing sees every row */
4173 } while (png_ptr
->num_rows
== 0 || png_ptr
->iwidth
== 0);
4175 if (png_ptr
->pass
< 7)
4178 #endif /* PNG_READ_INTERLACING_SUPPORTED */
4180 /* Here after at the end of the last row of the last pass. */
4181 png_read_finish_IDAT(png_ptr
);
4183 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
4186 png_read_start_row(png_structrp png_ptr
)
4188 #ifdef PNG_READ_INTERLACING_SUPPORTED
4189 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
4191 /* Start of interlace block */
4192 static PNG_CONST png_byte png_pass_start
[7] = {0, 4, 0, 2, 0, 1, 0};
4194 /* Offset to next interlace block */
4195 static PNG_CONST png_byte png_pass_inc
[7] = {8, 8, 4, 4, 2, 2, 1};
4197 /* Start of interlace block in the y direction */
4198 static PNG_CONST png_byte png_pass_ystart
[7] = {0, 0, 4, 0, 2, 0, 1};
4200 /* Offset to next interlace block in the y direction */
4201 static PNG_CONST png_byte png_pass_yinc
[7] = {8, 8, 8, 4, 4, 2, 2};
4204 int max_pixel_depth
;
4205 png_size_t row_bytes
;
4207 png_debug(1, "in png_read_start_row");
4209 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
4210 png_init_read_transformations(png_ptr
);
4212 #ifdef PNG_READ_INTERLACING_SUPPORTED
4213 if (png_ptr
->interlaced
)
4215 if (!(png_ptr
->transformations
& PNG_INTERLACE
))
4216 png_ptr
->num_rows
= (png_ptr
->height
+ png_pass_yinc
[0] - 1 -
4217 png_pass_ystart
[0]) / png_pass_yinc
[0];
4220 png_ptr
->num_rows
= png_ptr
->height
;
4222 png_ptr
->iwidth
= (png_ptr
->width
+
4223 png_pass_inc
[png_ptr
->pass
] - 1 -
4224 png_pass_start
[png_ptr
->pass
]) /
4225 png_pass_inc
[png_ptr
->pass
];
4229 #endif /* PNG_READ_INTERLACING_SUPPORTED */
4231 png_ptr
->num_rows
= png_ptr
->height
;
4232 png_ptr
->iwidth
= png_ptr
->width
;
4235 max_pixel_depth
= png_ptr
->pixel_depth
;
4237 /* WARNING: * png_read_transform_info (pngrtran.c) performs a simpliar set of
4238 * calculations to calculate the final pixel depth, then
4239 * png_do_read_transforms actually does the transforms. This means that the
4240 * code which effectively calculates this value is actually repeated in three
4241 * separate places. They must all match. Innocent changes to the order of
4242 * transformations can and will break libpng in a way that causes memory
4247 #ifdef PNG_READ_PACK_SUPPORTED
4248 if ((png_ptr
->transformations
& PNG_PACK
) && png_ptr
->bit_depth
< 8)
4249 max_pixel_depth
= 8;
4252 #ifdef PNG_READ_EXPAND_SUPPORTED
4253 if (png_ptr
->transformations
& PNG_EXPAND
)
4255 if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
4257 if (png_ptr
->num_trans
)
4258 max_pixel_depth
= 32;
4261 max_pixel_depth
= 24;
4264 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_GRAY
)
4266 if (max_pixel_depth
< 8)
4267 max_pixel_depth
= 8;
4269 if (png_ptr
->num_trans
)
4270 max_pixel_depth
*= 2;
4273 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_RGB
)
4275 if (png_ptr
->num_trans
)
4277 max_pixel_depth
*= 4;
4278 max_pixel_depth
/= 3;
4284 #ifdef PNG_READ_EXPAND_16_SUPPORTED
4285 if (png_ptr
->transformations
& PNG_EXPAND_16
)
4287 # ifdef PNG_READ_EXPAND_SUPPORTED
4288 /* In fact it is an error if it isn't supported, but checking is
4291 if (png_ptr
->transformations
& PNG_EXPAND
)
4293 if (png_ptr
->bit_depth
< 16)
4294 max_pixel_depth
*= 2;
4298 png_ptr
->transformations
&= ~PNG_EXPAND_16
;
4302 #ifdef PNG_READ_FILLER_SUPPORTED
4303 if (png_ptr
->transformations
& (PNG_FILLER
))
4305 if (png_ptr
->color_type
== PNG_COLOR_TYPE_GRAY
)
4307 if (max_pixel_depth
<= 8)
4308 max_pixel_depth
= 16;
4311 max_pixel_depth
= 32;
4314 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_RGB
||
4315 png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
4317 if (max_pixel_depth
<= 32)
4318 max_pixel_depth
= 32;
4321 max_pixel_depth
= 64;
4326 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
4327 if (png_ptr
->transformations
& PNG_GRAY_TO_RGB
)
4330 #ifdef PNG_READ_EXPAND_SUPPORTED
4331 (png_ptr
->num_trans
&& (png_ptr
->transformations
& PNG_EXPAND
)) ||
4333 #ifdef PNG_READ_FILLER_SUPPORTED
4334 (png_ptr
->transformations
& (PNG_FILLER
)) ||
4336 png_ptr
->color_type
== PNG_COLOR_TYPE_GRAY_ALPHA
)
4338 if (max_pixel_depth
<= 16)
4339 max_pixel_depth
= 32;
4342 max_pixel_depth
= 64;
4347 if (max_pixel_depth
<= 8)
4349 if (png_ptr
->color_type
== PNG_COLOR_TYPE_RGB_ALPHA
)
4350 max_pixel_depth
= 32;
4353 max_pixel_depth
= 24;
4356 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_RGB_ALPHA
)
4357 max_pixel_depth
= 64;
4360 max_pixel_depth
= 48;
4365 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) && \
4366 defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
4367 if (png_ptr
->transformations
& PNG_USER_TRANSFORM
)
4369 int user_pixel_depth
= png_ptr
->user_transform_depth
*
4370 png_ptr
->user_transform_channels
;
4372 if (user_pixel_depth
> max_pixel_depth
)
4373 max_pixel_depth
= user_pixel_depth
;
4377 /* This value is stored in png_struct and double checked in the row read
4380 png_ptr
->maximum_pixel_depth
= (png_byte
)max_pixel_depth
;
4381 png_ptr
->transformed_pixel_depth
= 0; /* calculated on demand */
4383 /* Align the width on the next larger 8 pixels. Mainly used
4386 row_bytes
= ((png_ptr
->width
+ 7) & ~((png_uint_32
)7));
4387 /* Calculate the maximum bytes needed, adding a byte and a pixel
4390 row_bytes
= PNG_ROWBYTES(max_pixel_depth
, row_bytes
) +
4391 1 + ((max_pixel_depth
+ 7) >> 3);
4393 #ifdef PNG_MAX_MALLOC_64K
4394 if (row_bytes
> (png_uint_32
)65536L)
4395 png_error(png_ptr
, "This image requires a row greater than 64KB");
4398 if (row_bytes
+ 48 > png_ptr
->old_big_row_buf_size
)
4400 png_free(png_ptr
, png_ptr
->big_row_buf
);
4401 png_free(png_ptr
, png_ptr
->big_prev_row
);
4403 if (png_ptr
->interlaced
)
4404 png_ptr
->big_row_buf
= (png_bytep
)png_calloc(png_ptr
,
4408 png_ptr
->big_row_buf
= (png_bytep
)png_malloc(png_ptr
, row_bytes
+ 48);
4410 png_ptr
->big_prev_row
= (png_bytep
)png_malloc(png_ptr
, row_bytes
+ 48);
4412 #ifdef PNG_ALIGNED_MEMORY_SUPPORTED
4413 /* Use 16-byte aligned memory for row_buf with at least 16 bytes
4414 * of padding before and after row_buf; treat prev_row similarly.
4415 * NOTE: the alignment is to the start of the pixels, one beyond the start
4416 * of the buffer, because of the filter byte. Prior to libpng 1.5.6 this
4417 * was incorrect; the filter byte was aligned, which had the exact
4418 * opposite effect of that intended.
4421 png_bytep temp
= png_ptr
->big_row_buf
+ 32;
4422 int extra
= (int)((temp
- (png_bytep
)0) & 0x0f);
4423 png_ptr
->row_buf
= temp
- extra
- 1/*filter byte*/;
4425 temp
= png_ptr
->big_prev_row
+ 32;
4426 extra
= (int)((temp
- (png_bytep
)0) & 0x0f);
4427 png_ptr
->prev_row
= temp
- extra
- 1/*filter byte*/;
4431 /* Use 31 bytes of padding before and 17 bytes after row_buf. */
4432 png_ptr
->row_buf
= png_ptr
->big_row_buf
+ 31;
4433 png_ptr
->prev_row
= png_ptr
->big_prev_row
+ 31;
4435 png_ptr
->old_big_row_buf_size
= row_bytes
+ 48;
4438 #ifdef PNG_MAX_MALLOC_64K
4439 if (png_ptr
->rowbytes
> 65535)
4440 png_error(png_ptr
, "This image requires a row greater than 64KB");
4443 if (png_ptr
->rowbytes
> (PNG_SIZE_MAX
- 1))
4444 png_error(png_ptr
, "Row has too many bytes to allocate in memory");
4446 memset(png_ptr
->prev_row
, 0, png_ptr
->rowbytes
+ 1);
4448 png_debug1(3, "width = %u,", png_ptr
->width
);
4449 png_debug1(3, "height = %u,", png_ptr
->height
);
4450 png_debug1(3, "iwidth = %u,", png_ptr
->iwidth
);
4451 png_debug1(3, "num_rows = %u,", png_ptr
->num_rows
);
4452 png_debug1(3, "rowbytes = %lu,", (unsigned long)png_ptr
->rowbytes
);
4453 png_debug1(3, "irowbytes = %lu",
4454 (unsigned long)PNG_ROWBYTES(png_ptr
->pixel_depth
, png_ptr
->iwidth
) + 1);
4456 /* The sequential reader needs a buffer for IDAT, but the progressive reader
4457 * does not, so free the read buffer now regardless; the sequential reader
4458 * reallocates it on demand.
4460 if (png_ptr
->read_buffer
)
4462 png_bytep buffer
= png_ptr
->read_buffer
;
4464 png_ptr
->read_buffer_size
= 0;
4465 png_ptr
->read_buffer
= NULL
;
4466 png_free(png_ptr
, buffer
);
4469 /* Finally claim the zstream for the inflate of the IDAT data, use the bits
4470 * value from the stream (note that this will result in a fatal error if the
4471 * IDAT stream has a bogus deflate header window_bits value, but this should
4472 * not be happening any longer!)
4474 if (png_inflate_claim(png_ptr
, png_IDAT
) != Z_OK
)
4475 png_error(png_ptr
, png_ptr
->zstream
.msg
);
4477 png_ptr
->flags
|= PNG_FLAG_ROW_INIT
;
4479 #endif /* PNG_READ_SUPPORTED */