2 /* pngrutil.c - utilities to read a PNG file
4 * Last changed in libpng 1.6.7 [November 14, 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 /* Manage the read buffer; this simply reallocates the buffer if it is not small
282 * enough (or if it is not allocated). The routine returns a pointer to the
283 * buffer; if an error occurs and 'warn' is set the routine returns NULL, else
284 * it will call png_error (via png_malloc) on failure. (warn == 2 means
288 png_read_buffer(png_structrp png_ptr, png_alloc_size_t new_size, int warn)
290 png_bytep buffer = png_ptr->read_buffer;
292 if (buffer != NULL && new_size > png_ptr->read_buffer_size)
294 png_ptr->read_buffer = NULL;
295 png_ptr->read_buffer = NULL;
296 png_ptr->read_buffer_size = 0;
297 png_free(png_ptr, buffer);
303 buffer = png_voidcast(png_bytep, png_malloc_base(png_ptr, new_size));
307 png_ptr->read_buffer = buffer;
308 png_ptr->read_buffer_size = new_size;
311 else if (warn < 2) /* else silent */
313 #ifdef PNG_WARNINGS_SUPPORTED
315 png_chunk_warning(png_ptr, "insufficient memory to read chunk");
319 #ifdef PNG_ERROR_TEXT_SUPPORTED
320 png_chunk_error(png_ptr, "insufficient memory to read chunk");
329 /* png_inflate_claim: claim the zstream for some nefarious purpose that involves
330 * decompression. Returns Z_OK on success, else a zlib error code. It checks
331 * the owner but, in final release builds, just issues a warning if some other
332 * chunk apparently owns the stream. Prior to release it does a png_error.
335 png_inflate_claim(png_structrp png_ptr, png_uint_32 owner)
337 if (png_ptr->zowner != 0)
341 PNG_STRING_FROM_CHUNK(msg, png_ptr->zowner);
342 /* So the message that results is "<chunk> using zstream"; this is an
343 * internal error, but is very useful for debugging. i18n requirements
346 (void)png_safecat(msg, (sizeof msg), 4, " using zstream");
347 # if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
348 png_chunk_warning(png_ptr, msg);
351 png_chunk_error(png_ptr, msg);
355 /* Implementation note: unlike 'png_deflate_claim' this internal function
356 * does not take the size of the data as an argument. Some efficiency could
357 * be gained by using this when it is known *if* the zlib stream itself does
358 * not record the number; however, this is an illusion: the original writer
359 * of the PNG may have selected a lower window size, and we really must
360 * follow that because, for systems with with limited capabilities, we
361 * would otherwise reject the application's attempts to use a smaller window
362 * size (zlib doesn't have an interface to say "this or lower"!).
364 * inflateReset2 was added to zlib 1.2.4; before this the window could not be
365 * reset, therefore it is necessary to always allocate the maximum window
366 * size with earlier zlibs just in case later compressed chunks need it.
369 int ret; /* zlib return code */
370 # if PNG_ZLIB_VERNUM >= 0x1240
372 # if defined(PNG_SET_OPTION_SUPPORTED) && \
373 defined(PNG_MAXIMUM_INFLATE_WINDOW)
376 if (((png_ptr->options >> PNG_MAXIMUM_INFLATE_WINDOW) & 3) ==
383 # define window_bits 0
387 /* Set this for safety, just in case the previous owner left pointers to
388 * memory allocations.
390 png_ptr->zstream.next_in = NULL;
391 png_ptr->zstream.avail_in = 0;
392 png_ptr->zstream.next_out = NULL;
393 png_ptr->zstream.avail_out = 0;
395 if (png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED)
397 # if PNG_ZLIB_VERNUM < 0x1240
398 ret = inflateReset(&png_ptr->zstream);
400 ret = inflateReset2(&png_ptr->zstream, window_bits);
406 # if PNG_ZLIB_VERNUM < 0x1240
407 ret = inflateInit(&png_ptr->zstream);
409 ret = inflateInit2(&png_ptr->zstream, window_bits);
413 png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED;
417 png_ptr->zowner = owner;
420 png_zstream_error(png_ptr, ret);
430 #ifdef PNG_READ_COMPRESSED_TEXT_SUPPORTED
431 /* png_inflate now returns zlib error codes including Z_OK and Z_STREAM_END to
432 * allow the caller to do multiple calls if required. If the 'finish' flag is
433 * set Z_FINISH will be passed to the final inflate() call and Z_STREAM_END must
434 * be returned or there has been a problem, otherwise Z_SYNC_FLUSH is used and
435 * Z_OK or Z_STREAM_END will be returned on success.
437 * The input and output sizes are updated to the actual amounts of data consumed
438 * or written, not the amount available (as in a z_stream). The data pointers
439 * are not changed, so the next input is (data+input_size) and the next
440 * available output is (output+output_size).
443 png_inflate(png_structrp png_ptr, png_uint_32 owner, int finish,
444 /* INPUT: */ png_const_bytep input, png_uint_32p input_size_ptr,
445 /* OUTPUT: */ png_bytep output, png_alloc_size_t *output_size_ptr)
447 if (png_ptr->zowner == owner) /* Else not claimed */
450 png_alloc_size_t avail_out = *output_size_ptr;
451 png_uint_32 avail_in = *input_size_ptr;
453 /* zlib can't necessarily handle more than 65535 bytes at once (i.e. it
454 * can't even necessarily handle 65536 bytes) because the type uInt is
455 * "16 bits or more". Consequently it is necessary to chunk the input to
456 * zlib. This code uses ZLIB_IO_MAX, from pngpriv.h, as the maximum (the
457 * maximum value that can be stored in a uInt.) It is possible to set
458 * ZLIB_IO_MAX to a lower value in pngpriv.h and this may sometimes have
459 * a performance advantage, because it reduces the amount of data accessed
460 * at each step and that may give the OS more time to page it in.
462 png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input);
463 /* avail_in and avail_out are set below from 'size' */
464 png_ptr->zstream.avail_in = 0;
465 png_ptr->zstream.avail_out = 0;
467 /* Read directly into the output if it is available (this is set to
468 * a local buffer below if output is NULL).
471 png_ptr->zstream.next_out = output;
476 Byte local_buffer[PNG_INFLATE_BUF_SIZE];
478 /* zlib INPUT BUFFER */
479 /* The setting of 'avail_in' used to be outside the loop; by setting it
480 * inside it is possible to chunk the input to zlib and simply rely on
481 * zlib to advance the 'next_in' pointer. This allows arbitrary
482 * amounts of data to be passed through zlib at the unavoidable cost of
483 * requiring a window save (memcpy of up to 32768 output bytes)
484 * every ZLIB_IO_MAX input bytes.
486 avail_in += png_ptr->zstream.avail_in; /* not consumed last time */
490 if (avail_in < avail)
491 avail = (uInt)avail_in; /* safe: < than ZLIB_IO_MAX */
494 png_ptr->zstream.avail_in = avail;
496 /* zlib OUTPUT BUFFER */
497 avail_out += png_ptr->zstream.avail_out; /* not written last time */
499 avail = ZLIB_IO_MAX; /* maximum zlib can process */
503 /* Reset the output buffer each time round if output is NULL and
504 * make available the full buffer, up to 'remaining_space'
506 png_ptr->zstream.next_out = local_buffer;
507 if ((sizeof local_buffer) < avail)
508 avail = (sizeof local_buffer);
511 if (avail_out < avail)
512 avail = (uInt)avail_out; /* safe: < ZLIB_IO_MAX */
514 png_ptr->zstream.avail_out = avail;
517 /* zlib inflate call */
518 /* In fact 'avail_out' may be 0 at this point, that happens at the end
519 * of the read when the final LZ end code was not passed at the end of
520 * the previous chunk of input data. Tell zlib if we have reached the
521 * end of the output buffer.
523 ret = inflate(&png_ptr->zstream, avail_out > 0 ? Z_NO_FLUSH :
524 (finish ? Z_FINISH : Z_SYNC_FLUSH));
525 } while (ret == Z_OK);
527 /* For safety kill the local buffer pointer now */
529 png_ptr->zstream.next_out = NULL;
531 /* Claw back the 'size' and 'remaining_space' byte counts. */
532 avail_in += png_ptr->zstream.avail_in;
533 avail_out += png_ptr->zstream.avail_out;
535 /* Update the input and output sizes; the updated values are the amount
536 * consumed or written, effectively the inverse of what zlib uses.
539 *output_size_ptr -= avail_out;
542 *input_size_ptr -= avail_in;
544 /* Ensure png_ptr->zstream.msg is set (even in the success case!) */
545 png_zstream_error(png_ptr, ret);
551 /* This is a bad internal error. The recovery assigns to the zstream msg
552 * pointer, which is not owned by the caller, but this is safe; it's only
555 png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed");
556 return Z_STREAM_ERROR;
561 * Decompress trailing data in a chunk. The assumption is that read_buffer
562 * points at an allocated area holding the contents of a chunk with a
563 * trailing compressed part. What we get back is an allocated area
564 * holding the original prefix part and an uncompressed version of the
565 * trailing part (the malloc area passed in is freed).
568 png_decompress_chunk(png_structrp png_ptr,
569 png_uint_32 chunklength, png_uint_32 prefix_size,
570 png_alloc_size_t *newlength /* must be initialized to the maximum! */,
571 int terminate /*add a '\0' to the end of the uncompressed data*/)
573 /* TODO: implement different limits for different types of chunk.
575 * The caller supplies *newlength set to the maximum length of the
576 * uncompressed data, but this routine allocates space for the prefix and
577 * maybe a '\0' terminator too. We have to assume that 'prefix_size' is
578 * limited only by the maximum chunk size.
580 png_alloc_size_t limit = PNG_SIZE_MAX;
582 # ifdef PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED
583 if (png_ptr->user_chunk_malloc_max > 0 &&
584 png_ptr->user_chunk_malloc_max < limit)
585 limit = png_ptr->user_chunk_malloc_max;
586 # elif PNG_USER_CHUNK_MALLOC_MAX > 0
587 if (PNG_USER_CHUNK_MALLOC_MAX < limit)
588 limit = PNG_USER_CHUNK_MALLOC_MAX;
591 if (limit >= prefix_size + (terminate != 0))
595 limit -= prefix_size + (terminate != 0);
597 if (limit < *newlength)
600 /* Now try to claim the stream. */
601 ret = png_inflate_claim(png_ptr, png_ptr->chunk_name);
605 png_uint_32 lzsize = chunklength - prefix_size;
607 ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/,
608 /* input: */ png_ptr->read_buffer + prefix_size, &lzsize,
609 /* output: */ NULL, newlength);
611 if (ret == Z_STREAM_END)
613 /* Use 'inflateReset' here, not 'inflateReset2' because this
614 * preserves the previously decided window size (otherwise it would
615 * be necessary to store the previous window size.) In practice
616 * this doesn't matter anyway, because png_inflate will call inflate
617 * with Z_FINISH in almost all cases, so the window will not be
620 if (inflateReset(&png_ptr->zstream) == Z_OK)
622 /* Because of the limit checks above we know that the new,
623 * expanded, size will fit in a size_t (let alone an
624 * png_alloc_size_t). Use png_malloc_base here to avoid an
627 png_alloc_size_t new_size = *newlength;
628 png_alloc_size_t buffer_size = prefix_size + new_size +
630 png_bytep text = png_voidcast(png_bytep, png_malloc_base(png_ptr,
635 ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/,
636 png_ptr->read_buffer + prefix_size, &lzsize,
637 text + prefix_size, newlength);
639 if (ret == Z_STREAM_END)
641 if (new_size == *newlength)
644 text[prefix_size + *newlength] = 0;
647 memcpy(text, png_ptr->read_buffer, prefix_size);
650 png_bytep old_ptr = png_ptr->read_buffer;
652 png_ptr->read_buffer = text;
653 png_ptr->read_buffer_size = buffer_size;
654 text = old_ptr; /* freed below */
660 /* The size changed on the second read, there can be no
661 * guarantee that anything is correct at this point.
662 * The 'msg' pointer has been set to "unexpected end of
663 * LZ stream", which is fine, but return an error code
664 * that the caller won't accept.
666 ret = PNG_UNEXPECTED_ZLIB_RETURN;
670 else if (ret == Z_OK)
671 ret = PNG_UNEXPECTED_ZLIB_RETURN; /* for safety */
673 /* Free the text pointer (this is the old read_buffer on
676 png_free(png_ptr, text);
678 /* This really is very benign, but it's still an error because
679 * the extra space may otherwise be used as a Trojan Horse.
681 if (ret == Z_STREAM_END &&
682 chunklength - prefix_size != lzsize)
683 png_chunk_benign_error(png_ptr, "extra compressed data");
688 /* Out of memory allocating the buffer */
690 png_zstream_error(png_ptr, Z_MEM_ERROR);
696 /* inflateReset failed, store the error message */
697 png_zstream_error(png_ptr, ret);
699 if (ret == Z_STREAM_END)
700 ret = PNG_UNEXPECTED_ZLIB_RETURN;
704 else if (ret == Z_OK)
705 ret = PNG_UNEXPECTED_ZLIB_RETURN;
707 /* Release the claimed stream */
711 else /* the claim failed */ if (ret == Z_STREAM_END) /* impossible! */
712 ret = PNG_UNEXPECTED_ZLIB_RETURN;
719 /* Application/configuration limits exceeded */
720 png_zstream_error(png_ptr, Z_MEM_ERROR);
724 #endif /* PNG_READ_COMPRESSED_TEXT_SUPPORTED */
726 #ifdef PNG_READ_iCCP_SUPPORTED
727 /* Perform a partial read and decompress, producing 'avail_out' bytes and
728 * reading from the current chunk as required.
731 png_inflate_read(png_structrp png_ptr, png_bytep read_buffer, uInt read_size,
732 png_uint_32p chunk_bytes, png_bytep next_out, png_alloc_size_t *out_size,
735 if (png_ptr->zowner == png_ptr->chunk_name)
739 /* next_in and avail_in must have been initialized by the caller. */
740 png_ptr->zstream.next_out = next_out;
741 png_ptr->zstream.avail_out = 0; /* set in the loop */
745 if (png_ptr->zstream.avail_in == 0)
747 if (read_size > *chunk_bytes)
748 read_size = (uInt)*chunk_bytes;
749 *chunk_bytes -= read_size;
752 png_crc_read(png_ptr, read_buffer, read_size);
754 png_ptr->zstream.next_in = read_buffer;
755 png_ptr->zstream.avail_in = read_size;
758 if (png_ptr->zstream.avail_out == 0)
760 uInt avail = ZLIB_IO_MAX;
761 if (avail > *out_size)
762 avail = (uInt)*out_size;
765 png_ptr->zstream.avail_out = avail;
768 /* Use Z_SYNC_FLUSH when there is no more chunk data to ensure that all
769 * the available output is produced; this allows reading of truncated
772 ret = inflate(&png_ptr->zstream,
773 *chunk_bytes > 0 ? Z_NO_FLUSH : (finish ? Z_FINISH : Z_SYNC_FLUSH));
775 while (ret == Z_OK && (*out_size > 0 || png_ptr->zstream.avail_out > 0));
777 *out_size += png_ptr->zstream.avail_out;
778 png_ptr->zstream.avail_out = 0; /* Should not be required, but is safe */
780 /* Ensure the error message pointer is always set: */
781 png_zstream_error(png_ptr, ret);
787 png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed");
788 return Z_STREAM_ERROR;
793 /* Read and check the IDHR chunk */
795 png_handle_IHDR(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
798 png_uint_32 width, height;
799 int bit_depth, color_type, compression_type, filter_type;
802 png_debug(1, "in png_handle_IHDR");
804 if (png_ptr->mode & PNG_HAVE_IHDR)
805 png_chunk_error(png_ptr, "out of place");
807 /* Check the length */
809 png_chunk_error(png_ptr, "invalid");
811 png_ptr->mode |= PNG_HAVE_IHDR;
813 png_crc_read(png_ptr, buf, 13);
814 png_crc_finish(png_ptr, 0);
816 width = png_get_uint_31(png_ptr, buf);
817 height = png_get_uint_31(png_ptr, buf + 4);
820 compression_type = buf[10];
821 filter_type = buf[11];
822 interlace_type = buf[12];
824 /* Set internal variables */
825 png_ptr->width = width;
826 png_ptr->height = height;
827 png_ptr->bit_depth = (png_byte)bit_depth;
828 png_ptr->interlaced = (png_byte)interlace_type;
829 png_ptr->color_type = (png_byte)color_type;
830 #ifdef PNG_MNG_FEATURES_SUPPORTED
831 png_ptr->filter_type = (png_byte)filter_type;
833 png_ptr->compression_type = (png_byte)compression_type;
835 /* Find number of channels */
836 switch (png_ptr->color_type)
838 default: /* invalid, png_set_IHDR calls png_error */
839 case PNG_COLOR_TYPE_GRAY:
840 case PNG_COLOR_TYPE_PALETTE:
841 png_ptr->channels = 1;
844 case PNG_COLOR_TYPE_RGB:
845 png_ptr->channels = 3;
848 case PNG_COLOR_TYPE_GRAY_ALPHA:
849 png_ptr->channels = 2;
852 case PNG_COLOR_TYPE_RGB_ALPHA:
853 png_ptr->channels = 4;
857 /* Set up other useful info */
858 png_ptr->pixel_depth = (png_byte)(png_ptr->bit_depth *
860 png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->width);
861 png_debug1(3, "bit_depth = %d", png_ptr->bit_depth);
862 png_debug1(3, "channels = %d", png_ptr->channels);
863 png_debug1(3, "rowbytes = %lu", (unsigned long)png_ptr->rowbytes);
864 png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth,
865 color_type, interlace_type, compression_type, filter_type);
868 /* Read and check the palette */
870 png_handle_PLTE(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
872 png_color palette[PNG_MAX_PALETTE_LENGTH];
874 #ifdef PNG_POINTER_INDEXING_SUPPORTED
878 png_debug(1, "in png_handle_PLTE");
880 if (!(png_ptr->mode & PNG_HAVE_IHDR))
881 png_chunk_error(png_ptr, "missing IHDR");
883 /* Moved to before the 'after IDAT' check below because otherwise duplicate
884 * PLTE chunks are potentially ignored (the spec says there shall not be more
885 * than one PLTE, the error is not treated as benign, so this check trumps
886 * the requirement that PLTE appears before IDAT.)
888 else if (png_ptr->mode & PNG_HAVE_PLTE)
889 png_chunk_error(png_ptr, "duplicate");
891 else if (png_ptr->mode & PNG_HAVE_IDAT)
893 /* This is benign because the non-benign error happened before, when an
894 * IDAT was encountered in a color-mapped image with no PLTE.
896 png_crc_finish(png_ptr, length);
897 png_chunk_benign_error(png_ptr, "out of place");
901 png_ptr->mode |= PNG_HAVE_PLTE;
903 if (!(png_ptr->color_type & PNG_COLOR_MASK_COLOR))
905 png_crc_finish(png_ptr, length);
906 png_chunk_benign_error(png_ptr, "ignored in grayscale PNG");
910 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
911 if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
913 png_crc_finish(png_ptr, length);
918 if (length > 3*PNG_MAX_PALETTE_LENGTH || length % 3)
920 png_crc_finish(png_ptr, length);
922 if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
923 png_chunk_benign_error(png_ptr, "invalid");
926 png_chunk_error(png_ptr, "invalid");
931 /* The cast is safe because 'length' is less than 3*PNG_MAX_PALETTE_LENGTH */
932 num = (int)length / 3;
934 #ifdef PNG_POINTER_INDEXING_SUPPORTED
935 for (i = 0, pal_ptr = palette; i < num; i++, pal_ptr++)
939 png_crc_read(png_ptr, buf, 3);
940 pal_ptr->red = buf[0];
941 pal_ptr->green = buf[1];
942 pal_ptr->blue = buf[2];
945 for (i = 0; i < num; i++)
949 png_crc_read(png_ptr, buf, 3);
950 /* Don't depend upon png_color being any order */
951 palette[i].red = buf[0];
952 palette[i].green = buf[1];
953 palette[i].blue = buf[2];
957 /* If we actually need the PLTE chunk (ie for a paletted image), we do
958 * whatever the normal CRC configuration tells us. However, if we
959 * have an RGB image, the PLTE can be considered ancillary, so
960 * we will act as though it is.
962 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
963 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
966 png_crc_finish(png_ptr, 0);
969 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
970 else if (png_crc_error(png_ptr)) /* Only if we have a CRC error */
972 /* If we don't want to use the data from an ancillary chunk,
973 * we have two options: an error abort, or a warning and we
974 * ignore the data in this chunk (which should be OK, since
975 * it's considered ancillary for a RGB or RGBA image).
977 * IMPLEMENTATION NOTE: this is only here because png_crc_finish uses the
978 * chunk type to determine whether to check the ancillary or the critical
981 if (!(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_USE))
983 if (png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN)
985 png_chunk_benign_error(png_ptr, "CRC error");
990 png_chunk_warning(png_ptr, "CRC error");
995 /* Otherwise, we (optionally) emit a warning and use the chunk. */
996 else if (!(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN))
998 png_chunk_warning(png_ptr, "CRC error");
1003 /* TODO: png_set_PLTE has the side effect of setting png_ptr->palette to its
1004 * own copy of the palette. This has the side effect that when png_start_row
1005 * is called (this happens after any call to png_read_update_info) the
1006 * info_ptr palette gets changed. This is extremely unexpected and
1009 * Fix this by not sharing the palette in this way.
1011 png_set_PLTE(png_ptr, info_ptr, palette, num);
1013 /* The three chunks, bKGD, hIST and tRNS *must* appear after PLTE and before
1014 * IDAT. Prior to 1.6.0 this was not checked; instead the code merely
1015 * checked the apparent validity of a tRNS chunk inserted before PLTE on a
1016 * palette PNG. 1.6.0 attempts to rigorously follow the standard and
1017 * therefore does a benign error if the erroneous condition is detected *and*
1018 * cancels the tRNS if the benign error returns. The alternative is to
1019 * amend the standard since it would be rather hypocritical of the standards
1020 * maintainers to ignore it.
1022 #ifdef PNG_READ_tRNS_SUPPORTED
1023 if (png_ptr->num_trans > 0 ||
1024 (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0))
1026 /* Cancel this because otherwise it would be used if the transforms
1027 * require it. Don't cancel the 'valid' flag because this would prevent
1028 * detection of duplicate chunks.
1030 png_ptr->num_trans = 0;
1032 if (info_ptr != NULL)
1033 info_ptr->num_trans = 0;
1035 png_chunk_benign_error(png_ptr, "tRNS must be after");
1039 #ifdef PNG_READ_hIST_SUPPORTED
1040 if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0)
1041 png_chunk_benign_error(png_ptr, "hIST must be after");
1044 #ifdef PNG_READ_bKGD_SUPPORTED
1045 if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0)
1046 png_chunk_benign_error(png_ptr, "bKGD must be after");
1051 png_handle_IEND(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1053 png_debug(1, "in png_handle_IEND");
1055 if (!(png_ptr->mode & PNG_HAVE_IHDR) || !(png_ptr->mode & PNG_HAVE_IDAT))
1056 png_chunk_error(png_ptr, "out of place");
1058 png_ptr->mode |= (PNG_AFTER_IDAT | PNG_HAVE_IEND);
1060 png_crc_finish(png_ptr, length);
1063 png_chunk_benign_error(png_ptr, "invalid");
1065 PNG_UNUSED(info_ptr)
1068 #ifdef PNG_READ_gAMA_SUPPORTED
1070 png_handle_gAMA(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1072 png_fixed_point igamma;
1075 png_debug(1, "in png_handle_gAMA");
1077 if (!(png_ptr->mode & PNG_HAVE_IHDR))
1078 png_chunk_error(png_ptr, "missing IHDR");
1080 else if (png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE))
1082 png_crc_finish(png_ptr, length);
1083 png_chunk_benign_error(png_ptr, "out of place");
1089 png_crc_finish(png_ptr, length);
1090 png_chunk_benign_error(png_ptr, "invalid");
1094 png_crc_read(png_ptr, buf, 4);
1096 if (png_crc_finish(png_ptr, 0))
1099 igamma = png_get_fixed_point(NULL, buf);
1101 png_colorspace_set_gamma(png_ptr, &png_ptr->colorspace, igamma);
1102 png_colorspace_sync(png_ptr, info_ptr);
1106 #ifdef PNG_READ_sBIT_SUPPORTED
1108 png_handle_sBIT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1110 unsigned int truelen;
1113 png_debug(1, "in png_handle_sBIT");
1115 buf[0] = buf[1] = buf[2] = buf[3] = 0;
1117 if (!(png_ptr->mode & PNG_HAVE_IHDR))
1118 png_chunk_error(png_ptr, "missing IHDR");
1120 else if (png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE))
1122 png_crc_finish(png_ptr, length);
1123 png_chunk_benign_error(png_ptr, "out of place");
1127 if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT))
1129 png_crc_finish(png_ptr, length);
1130 png_chunk_benign_error(png_ptr, "duplicate");
1134 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1138 truelen = png_ptr->channels;
1140 if (length != truelen || length > 4)
1142 png_chunk_benign_error(png_ptr, "invalid");
1143 png_crc_finish(png_ptr, length);
1147 png_crc_read(png_ptr, buf, truelen);
1149 if (png_crc_finish(png_ptr, 0))
1152 if (png_ptr->color_type & PNG_COLOR_MASK_COLOR)
1154 png_ptr->sig_bit.red = buf[0];
1155 png_ptr->sig_bit.green = buf[1];
1156 png_ptr->sig_bit.blue = buf[2];
1157 png_ptr->sig_bit.alpha = buf[3];
1162 png_ptr->sig_bit.gray = buf[0];
1163 png_ptr->sig_bit.red = buf[0];
1164 png_ptr->sig_bit.green = buf[0];
1165 png_ptr->sig_bit.blue = buf[0];
1166 png_ptr->sig_bit.alpha = buf[1];
1169 png_set_sBIT(png_ptr, info_ptr, &(png_ptr->sig_bit));
1173 #ifdef PNG_READ_cHRM_SUPPORTED
1175 png_handle_cHRM(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1180 png_debug(1, "in png_handle_cHRM");
1182 if (!(png_ptr->mode & PNG_HAVE_IHDR))
1183 png_chunk_error(png_ptr, "missing IHDR");
1185 else if (png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE))
1187 png_crc_finish(png_ptr, length);
1188 png_chunk_benign_error(png_ptr, "out of place");
1194 png_crc_finish(png_ptr, length);
1195 png_chunk_benign_error(png_ptr, "invalid");
1199 png_crc_read(png_ptr, buf, 32);
1201 if (png_crc_finish(png_ptr, 0))
1204 xy.whitex = png_get_fixed_point(NULL, buf);
1205 xy.whitey = png_get_fixed_point(NULL, buf + 4);
1206 xy.redx = png_get_fixed_point(NULL, buf + 8);
1207 xy.redy = png_get_fixed_point(NULL, buf + 12);
1208 xy.greenx = png_get_fixed_point(NULL, buf + 16);
1209 xy.greeny = png_get_fixed_point(NULL, buf + 20);
1210 xy.bluex = png_get_fixed_point(NULL, buf + 24);
1211 xy.bluey = png_get_fixed_point(NULL, buf + 28);
1213 if (xy.whitex == PNG_FIXED_ERROR ||
1214 xy.whitey == PNG_FIXED_ERROR ||
1215 xy.redx == PNG_FIXED_ERROR ||
1216 xy.redy == PNG_FIXED_ERROR ||
1217 xy.greenx == PNG_FIXED_ERROR ||
1218 xy.greeny == PNG_FIXED_ERROR ||
1219 xy.bluex == PNG_FIXED_ERROR ||
1220 xy.bluey == PNG_FIXED_ERROR)
1222 png_chunk_benign_error(png_ptr, "invalid values");
1226 /* If a colorspace error has already been output skip this chunk */
1227 if (png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID)
1230 if (png_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM)
1232 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
1233 png_colorspace_sync(png_ptr, info_ptr);
1234 png_chunk_benign_error(png_ptr, "duplicate");
1238 png_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;
1239 (void)png_colorspace_set_chromaticities(png_ptr, &png_ptr->colorspace, &xy,
1240 1/*prefer cHRM values*/);
1241 png_colorspace_sync(png_ptr, info_ptr);
1245 #ifdef PNG_READ_sRGB_SUPPORTED
1247 png_handle_sRGB(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1251 png_debug(1, "in png_handle_sRGB");
1253 if (!(png_ptr->mode & PNG_HAVE_IHDR))
1254 png_chunk_error(png_ptr, "missing IHDR");
1256 else if (png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE))
1258 png_crc_finish(png_ptr, length);
1259 png_chunk_benign_error(png_ptr, "out of place");
1265 png_crc_finish(png_ptr, length);
1266 png_chunk_benign_error(png_ptr, "invalid");
1270 png_crc_read(png_ptr, &intent, 1);
1272 if (png_crc_finish(png_ptr, 0))
1275 /* If a colorspace error has already been output skip this chunk */
1276 if (png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID)
1279 /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
1282 if (png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT)
1284 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
1285 png_colorspace_sync(png_ptr, info_ptr);
1286 png_chunk_benign_error(png_ptr, "too many profiles");
1290 (void)png_colorspace_set_sRGB(png_ptr, &png_ptr->colorspace, intent);
1291 png_colorspace_sync(png_ptr, info_ptr);
1293 #endif /* PNG_READ_sRGB_SUPPORTED */
1295 #ifdef PNG_READ_iCCP_SUPPORTED
1297 png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1298 /* Note: this does not properly handle profiles that are > 64K under DOS */
1300 png_const_charp errmsg = NULL; /* error message output, or no error */
1301 int finished = 0; /* crc checked */
1303 png_debug(1, "in png_handle_iCCP");
1305 if (!(png_ptr->mode & PNG_HAVE_IHDR))
1306 png_chunk_error(png_ptr, "missing IHDR");
1308 else if (png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE))
1310 png_crc_finish(png_ptr, length);
1311 png_chunk_benign_error(png_ptr, "out of place");
1315 /* Consistent with all the above colorspace handling an obviously *invalid*
1316 * chunk is just ignored, so does not invalidate the color space. An
1317 * alternative is to set the 'invalid' flags at the start of this routine
1318 * and only clear them in they were not set before and all the tests pass.
1319 * The minimum 'deflate' stream is assumed to be just the 2 byte header and 4
1320 * byte checksum. The keyword must be one character and there is a
1321 * terminator (0) byte and the compression method.
1325 png_crc_finish(png_ptr, length);
1326 png_chunk_benign_error(png_ptr, "too short");
1330 /* If a colorspace error has already been output skip this chunk */
1331 if (png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID)
1333 png_crc_finish(png_ptr, length);
1337 /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
1340 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) == 0)
1342 uInt read_length, keyword_length;
1345 /* Find the keyword; the keyword plus separator and compression method
1346 * bytes can be at most 81 characters long.
1348 read_length = 81; /* maximum */
1349 if (read_length > length)
1350 read_length = (uInt)length;
1352 png_crc_read(png_ptr, (png_bytep)keyword, read_length);
1353 length -= read_length;
1356 while (keyword_length < 80 && keyword_length < read_length &&
1357 keyword[keyword_length] != 0)
1360 /* TODO: make the keyword checking common */
1361 if (keyword_length >= 1 && keyword_length <= 79)
1363 /* We only understand '0' compression - deflate - so if we get a
1364 * different value we can't safely decode the chunk.
1366 if (keyword_length+1 < read_length &&
1367 keyword[keyword_length+1] == PNG_COMPRESSION_TYPE_BASE)
1369 read_length -= keyword_length+2;
1371 if (png_inflate_claim(png_ptr, png_iCCP) == Z_OK)
1373 Byte profile_header[132];
1374 Byte local_buffer[PNG_INFLATE_BUF_SIZE];
1375 png_alloc_size_t size = (sizeof profile_header);
1377 png_ptr->zstream.next_in = (Bytef*)keyword + (keyword_length+2);
1378 png_ptr->zstream.avail_in = read_length;
1379 (void)png_inflate_read(png_ptr, local_buffer,
1380 (sizeof local_buffer), &length, profile_header, &size,
1381 0/*finish: don't, because the output is too small*/);
1385 /* We have the ICC profile header; do the basic header checks.
1387 const png_uint_32 profile_length =
1388 png_get_uint_32(profile_header);
1390 if (png_icc_check_length(png_ptr, &png_ptr->colorspace,
1391 keyword, profile_length))
1393 /* The length is apparently ok, so we can check the 132
1396 if (png_icc_check_header(png_ptr, &png_ptr->colorspace,
1397 keyword, profile_length, profile_header,
1398 png_ptr->color_type))
1400 /* Now read the tag table; a variable size buffer is
1401 * needed at this point, allocate one for the whole
1402 * profile. The header check has already validated
1403 * that none of these stuff will overflow.
1405 const png_uint_32 tag_count = png_get_uint_32(
1406 profile_header+128);
1407 png_bytep profile = png_read_buffer(png_ptr,
1408 profile_length, 2/*silent*/);
1410 if (profile != NULL)
1412 memcpy(profile, profile_header,
1413 (sizeof profile_header));
1415 size = 12 * tag_count;
1417 (void)png_inflate_read(png_ptr, local_buffer,
1418 (sizeof local_buffer), &length,
1419 profile + (sizeof profile_header), &size, 0);
1421 /* Still expect a a buffer error because we expect
1422 * there to be some tag data!
1426 if (png_icc_check_tag_table(png_ptr,
1427 &png_ptr->colorspace, keyword, profile_length,
1430 /* The profile has been validated for basic
1431 * security issues, so read the whole thing in.
1433 size = profile_length - (sizeof profile_header)
1436 (void)png_inflate_read(png_ptr, local_buffer,
1437 (sizeof local_buffer), &length,
1438 profile + (sizeof profile_header) +
1439 12 * tag_count, &size, 1/*finish*/);
1441 if (length > 0 && !(png_ptr->flags &
1442 PNG_FLAG_BENIGN_ERRORS_WARN))
1443 errmsg = "extra compressed data";
1445 /* But otherwise allow extra data: */
1450 /* This can be handled completely, so
1453 png_chunk_warning(png_ptr,
1454 "extra compressed data");
1457 png_crc_finish(png_ptr, length);
1460 # ifdef PNG_sRGB_SUPPORTED
1461 /* Check for a match against sRGB */
1462 png_icc_set_sRGB(png_ptr,
1463 &png_ptr->colorspace, profile,
1464 png_ptr->zstream.adler);
1467 /* Steal the profile for info_ptr. */
1468 if (info_ptr != NULL)
1470 png_free_data(png_ptr, info_ptr,
1473 info_ptr->iccp_name = png_voidcast(char*,
1474 png_malloc_base(png_ptr,
1476 if (info_ptr->iccp_name != NULL)
1478 memcpy(info_ptr->iccp_name, keyword,
1480 info_ptr->iccp_proflen =
1482 info_ptr->iccp_profile = profile;
1483 png_ptr->read_buffer = NULL; /*steal*/
1484 info_ptr->free_me |= PNG_FREE_ICCP;
1485 info_ptr->valid |= PNG_INFO_iCCP;
1490 png_ptr->colorspace.flags |=
1491 PNG_COLORSPACE_INVALID;
1492 errmsg = "out of memory";
1496 /* else the profile remains in the read
1497 * buffer which gets reused for subsequent
1501 if (info_ptr != NULL)
1502 png_colorspace_sync(png_ptr, info_ptr);
1506 png_ptr->zowner = 0;
1512 errmsg = "truncated";
1515 errmsg = png_ptr->zstream.msg;
1518 /* else png_icc_check_tag_table output an error */
1521 else /* profile truncated */
1522 errmsg = png_ptr->zstream.msg;
1526 errmsg = "out of memory";
1529 /* else png_icc_check_header output an error */
1532 /* else png_icc_check_length output an error */
1535 else /* profile truncated */
1536 errmsg = png_ptr->zstream.msg;
1538 /* Release the stream */
1539 png_ptr->zowner = 0;
1542 else /* png_inflate_claim failed */
1543 errmsg = png_ptr->zstream.msg;
1547 errmsg = "bad compression method"; /* or missing */
1551 errmsg = "bad keyword";
1555 errmsg = "too many profiles";
1557 /* Failure: the reason is in 'errmsg' */
1559 png_crc_finish(png_ptr, length);
1561 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
1562 png_colorspace_sync(png_ptr, info_ptr);
1563 if (errmsg != NULL) /* else already output */
1564 png_chunk_benign_error(png_ptr, errmsg);
1566 #endif /* PNG_READ_iCCP_SUPPORTED */
1568 #ifdef PNG_READ_sPLT_SUPPORTED
1570 png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1571 /* Note: this does not properly handle chunks that are > 64K under DOS */
1573 png_bytep entry_start, buffer;
1574 png_sPLT_t new_palette;
1576 png_uint_32 data_length;
1578 png_uint_32 skip = 0;
1582 png_debug(1, "in png_handle_sPLT");
1584 #ifdef PNG_USER_LIMITS_SUPPORTED
1585 if (png_ptr->user_chunk_cache_max != 0)
1587 if (png_ptr->user_chunk_cache_max == 1)
1589 png_crc_finish(png_ptr, length);
1593 if (--png_ptr->user_chunk_cache_max == 1)
1595 png_warning(png_ptr, "No space in chunk cache for sPLT");
1596 png_crc_finish(png_ptr, length);
1602 if (!(png_ptr->mode & PNG_HAVE_IHDR))
1603 png_chunk_error(png_ptr, "missing IHDR");
1605 else if (png_ptr->mode & PNG_HAVE_IDAT)
1607 png_crc_finish(png_ptr, length);
1608 png_chunk_benign_error(png_ptr, "out of place");
1612 #ifdef PNG_MAX_MALLOC_64K
1613 if (length > 65535U)
1615 png_crc_finish(png_ptr, length);
1616 png_chunk_benign_error(png_ptr, "too large to fit in memory");
1621 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
1624 png_crc_finish(png_ptr, length);
1625 png_chunk_benign_error(png_ptr, "out of memory");
1630 /* WARNING: this may break if size_t is less than 32 bits; it is assumed
1631 * that the PNG_MAX_MALLOC_64K test is enabled in this case, but this is a
1632 * potential breakage point if the types in pngconf.h aren't exactly right.
1634 png_crc_read(png_ptr, buffer, length);
1636 if (png_crc_finish(png_ptr, skip))
1641 for (entry_start = buffer; *entry_start; entry_start++)
1642 /* Empty loop to find end of name */ ;
1646 /* A sample depth should follow the separator, and we should be on it */
1647 if (entry_start > buffer + length - 2)
1649 png_warning(png_ptr, "malformed sPLT chunk");
1653 new_palette.depth = *entry_start++;
1654 entry_size = (new_palette.depth == 8 ? 6 : 10);
1655 /* This must fit in a png_uint_32 because it is derived from the original
1656 * chunk data length.
1658 data_length = length - (png_uint_32)(entry_start - buffer);
1660 /* Integrity-check the data length */
1661 if (data_length % entry_size)
1663 png_warning(png_ptr, "sPLT chunk has bad length");
1667 dl = (png_int_32)(data_length / entry_size);
1668 max_dl = PNG_SIZE_MAX / (sizeof (png_sPLT_entry));
1672 png_warning(png_ptr, "sPLT chunk too long");
1676 new_palette.nentries = (png_int_32)(data_length / entry_size);
1678 new_palette.entries = (png_sPLT_entryp)png_malloc_warn(
1679 png_ptr, new_palette.nentries * (sizeof (png_sPLT_entry)));
1681 if (new_palette.entries == NULL)
1683 png_warning(png_ptr, "sPLT chunk requires too much memory");
1687 #ifdef PNG_POINTER_INDEXING_SUPPORTED
1688 for (i = 0; i < new_palette.nentries; i++)
1690 pp = new_palette.entries + i;
1692 if (new_palette.depth == 8)
1694 pp->red = *entry_start++;
1695 pp->green = *entry_start++;
1696 pp->blue = *entry_start++;
1697 pp->alpha = *entry_start++;
1702 pp->red = png_get_uint_16(entry_start); entry_start += 2;
1703 pp->green = png_get_uint_16(entry_start); entry_start += 2;
1704 pp->blue = png_get_uint_16(entry_start); entry_start += 2;
1705 pp->alpha = png_get_uint_16(entry_start); entry_start += 2;
1708 pp->frequency = png_get_uint_16(entry_start); entry_start += 2;
1711 pp = new_palette.entries;
1713 for (i = 0; i < new_palette.nentries; i++)
1716 if (new_palette.depth == 8)
1718 pp[i].red = *entry_start++;
1719 pp[i].green = *entry_start++;
1720 pp[i].blue = *entry_start++;
1721 pp[i].alpha = *entry_start++;
1726 pp[i].red = png_get_uint_16(entry_start); entry_start += 2;
1727 pp[i].green = png_get_uint_16(entry_start); entry_start += 2;
1728 pp[i].blue = png_get_uint_16(entry_start); entry_start += 2;
1729 pp[i].alpha = png_get_uint_16(entry_start); entry_start += 2;
1732 pp[i].frequency = png_get_uint_16(entry_start); entry_start += 2;
1736 /* Discard all chunk data except the name and stash that */
1737 new_palette.name = (png_charp)buffer;
1739 png_set_sPLT(png_ptr, info_ptr, &new_palette, 1);
1741 png_free(png_ptr, new_palette.entries);
1743 #endif /* PNG_READ_sPLT_SUPPORTED */
1745 #ifdef PNG_READ_tRNS_SUPPORTED
1747 png_handle_tRNS(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1749 png_byte readbuf[PNG_MAX_PALETTE_LENGTH];
1751 png_debug(1, "in png_handle_tRNS");
1753 if (!(png_ptr->mode & PNG_HAVE_IHDR))
1754 png_chunk_error(png_ptr, "missing IHDR");
1756 else if (png_ptr->mode & PNG_HAVE_IDAT)
1758 png_crc_finish(png_ptr, length);
1759 png_chunk_benign_error(png_ptr, "out of place");
1763 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS))
1765 png_crc_finish(png_ptr, length);
1766 png_chunk_benign_error(png_ptr, "duplicate");
1770 if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
1776 png_crc_finish(png_ptr, length);
1777 png_chunk_benign_error(png_ptr, "invalid");
1781 png_crc_read(png_ptr, buf, 2);
1782 png_ptr->num_trans = 1;
1783 png_ptr->trans_color.gray = png_get_uint_16(buf);
1786 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
1792 png_crc_finish(png_ptr, length);
1793 png_chunk_benign_error(png_ptr, "invalid");
1797 png_crc_read(png_ptr, buf, length);
1798 png_ptr->num_trans = 1;
1799 png_ptr->trans_color.red = png_get_uint_16(buf);
1800 png_ptr->trans_color.green = png_get_uint_16(buf + 2);
1801 png_ptr->trans_color.blue = png_get_uint_16(buf + 4);
1804 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1806 if (!(png_ptr->mode & PNG_HAVE_PLTE))
1808 /* TODO: is this actually an error in the ISO spec? */
1809 png_crc_finish(png_ptr, length);
1810 png_chunk_benign_error(png_ptr, "out of place");
1814 if (length > png_ptr->num_palette || length > PNG_MAX_PALETTE_LENGTH ||
1817 png_crc_finish(png_ptr, length);
1818 png_chunk_benign_error(png_ptr, "invalid");
1822 png_crc_read(png_ptr, readbuf, length);
1823 png_ptr->num_trans = (png_uint_16)length;
1828 png_crc_finish(png_ptr, length);
1829 png_chunk_benign_error(png_ptr, "invalid with alpha channel");
1833 if (png_crc_finish(png_ptr, 0))
1835 png_ptr->num_trans = 0;
1839 /* TODO: this is a horrible side effect in the palette case because the
1840 * png_struct ends up with a pointer to the tRNS buffer owned by the
1841 * png_info. Fix this.
1843 png_set_tRNS(png_ptr, info_ptr, readbuf, png_ptr->num_trans,
1844 &(png_ptr->trans_color));
1848 #ifdef PNG_READ_bKGD_SUPPORTED
1850 png_handle_bKGD(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1852 unsigned int truelen;
1854 png_color_16 background;
1856 png_debug(1, "in png_handle_bKGD");
1858 if (!(png_ptr->mode & PNG_HAVE_IHDR))
1859 png_chunk_error(png_ptr, "missing IHDR");
1861 else if ((png_ptr->mode & PNG_HAVE_IDAT) ||
1862 (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
1863 !(png_ptr->mode & PNG_HAVE_PLTE)))
1865 png_crc_finish(png_ptr, length);
1866 png_chunk_benign_error(png_ptr, "out of place");
1870 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD))
1872 png_crc_finish(png_ptr, length);
1873 png_chunk_benign_error(png_ptr, "duplicate");
1877 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1880 else if (png_ptr->color_type & PNG_COLOR_MASK_COLOR)
1886 if (length != truelen)
1888 png_crc_finish(png_ptr, length);
1889 png_chunk_benign_error(png_ptr, "invalid");
1893 png_crc_read(png_ptr, buf, truelen);
1895 if (png_crc_finish(png_ptr, 0))
1898 /* We convert the index value into RGB components so that we can allow
1899 * arbitrary RGB values for background when we have transparency, and
1900 * so it is easy to determine the RGB values of the background color
1901 * from the info_ptr struct.
1903 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1905 background.index = buf[0];
1907 if (info_ptr && info_ptr->num_palette)
1909 if (buf[0] >= info_ptr->num_palette)
1911 png_chunk_benign_error(png_ptr, "invalid index");
1915 background.red = (png_uint_16)png_ptr->palette[buf[0]].red;
1916 background.green = (png_uint_16)png_ptr->palette[buf[0]].green;
1917 background.blue = (png_uint_16)png_ptr->palette[buf[0]].blue;
1921 background.red = background.green = background.blue = 0;
1923 background.gray = 0;
1926 else if (!(png_ptr->color_type & PNG_COLOR_MASK_COLOR)) /* GRAY */
1928 background.index = 0;
1932 background.gray = png_get_uint_16(buf);
1937 background.index = 0;
1938 background.red = png_get_uint_16(buf);
1939 background.green = png_get_uint_16(buf + 2);
1940 background.blue = png_get_uint_16(buf + 4);
1941 background.gray = 0;
1944 png_set_bKGD(png_ptr, info_ptr, &background);
1948 #ifdef PNG_READ_hIST_SUPPORTED
1950 png_handle_hIST(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1952 unsigned int num, i;
1953 png_uint_16 readbuf[PNG_MAX_PALETTE_LENGTH];
1955 png_debug(1, "in png_handle_hIST");
1957 if (!(png_ptr->mode & PNG_HAVE_IHDR))
1958 png_chunk_error(png_ptr, "missing IHDR");
1960 else if ((png_ptr->mode & PNG_HAVE_IDAT) || !(png_ptr->mode & PNG_HAVE_PLTE))
1962 png_crc_finish(png_ptr, length);
1963 png_chunk_benign_error(png_ptr, "out of place");
1967 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST))
1969 png_crc_finish(png_ptr, length);
1970 png_chunk_benign_error(png_ptr, "duplicate");
1976 if (num != png_ptr->num_palette || num > PNG_MAX_PALETTE_LENGTH)
1978 png_crc_finish(png_ptr, length);
1979 png_chunk_benign_error(png_ptr, "invalid");
1983 for (i = 0; i < num; i++)
1987 png_crc_read(png_ptr, buf, 2);
1988 readbuf[i] = png_get_uint_16(buf);
1991 if (png_crc_finish(png_ptr, 0))
1994 png_set_hIST(png_ptr, info_ptr, readbuf);
1998 #ifdef PNG_READ_pHYs_SUPPORTED
2000 png_handle_pHYs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2003 png_uint_32 res_x, res_y;
2006 png_debug(1, "in png_handle_pHYs");
2008 if (!(png_ptr->mode & PNG_HAVE_IHDR))
2009 png_chunk_error(png_ptr, "missing IHDR");
2011 else if (png_ptr->mode & PNG_HAVE_IDAT)
2013 png_crc_finish(png_ptr, length);
2014 png_chunk_benign_error(png_ptr, "out of place");
2018 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
2020 png_crc_finish(png_ptr, length);
2021 png_chunk_benign_error(png_ptr, "duplicate");
2027 png_crc_finish(png_ptr, length);
2028 png_chunk_benign_error(png_ptr, "invalid");
2032 png_crc_read(png_ptr, buf, 9);
2034 if (png_crc_finish(png_ptr, 0))
2037 res_x = png_get_uint_32(buf);
2038 res_y = png_get_uint_32(buf + 4);
2040 png_set_pHYs(png_ptr, info_ptr, res_x, res_y, unit_type);
2044 #ifdef PNG_READ_oFFs_SUPPORTED
2046 png_handle_oFFs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2049 png_int_32 offset_x, offset_y;
2052 png_debug(1, "in png_handle_oFFs");
2054 if (!(png_ptr->mode & PNG_HAVE_IHDR))
2055 png_chunk_error(png_ptr, "missing IHDR");
2057 else if (png_ptr->mode & PNG_HAVE_IDAT)
2059 png_crc_finish(png_ptr, length);
2060 png_chunk_benign_error(png_ptr, "out of place");
2064 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs))
2066 png_crc_finish(png_ptr, length);
2067 png_chunk_benign_error(png_ptr, "duplicate");
2073 png_crc_finish(png_ptr, length);
2074 png_chunk_benign_error(png_ptr, "invalid");
2078 png_crc_read(png_ptr, buf, 9);
2080 if (png_crc_finish(png_ptr, 0))
2083 offset_x = png_get_int_32(buf);
2084 offset_y = png_get_int_32(buf + 4);
2086 png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y, unit_type);
2090 #ifdef PNG_READ_pCAL_SUPPORTED
2091 /* Read the pCAL chunk (described in the PNG Extensions document) */
2093 png_handle_pCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2096 png_byte type, nparams;
2097 png_bytep buffer, buf, units, endptr;
2101 png_debug(1, "in png_handle_pCAL");
2103 if (!(png_ptr->mode & PNG_HAVE_IHDR))
2104 png_chunk_error(png_ptr, "missing IHDR");
2106 else if (png_ptr->mode & PNG_HAVE_IDAT)
2108 png_crc_finish(png_ptr, length);
2109 png_chunk_benign_error(png_ptr, "out of place");
2113 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL))
2115 png_crc_finish(png_ptr, length);
2116 png_chunk_benign_error(png_ptr, "duplicate");
2120 png_debug1(2, "Allocating and reading pCAL chunk data (%u bytes)",
2123 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
2127 png_crc_finish(png_ptr, length);
2128 png_chunk_benign_error(png_ptr, "out of memory");
2132 png_crc_read(png_ptr, buffer, length);
2134 if (png_crc_finish(png_ptr, 0))
2137 buffer[length] = 0; /* Null terminate the last string */
2139 png_debug(3, "Finding end of pCAL purpose string");
2140 for (buf = buffer; *buf; buf++)
2143 endptr = buffer + length;
2145 /* We need to have at least 12 bytes after the purpose string
2146 * in order to get the parameter information.
2148 if (endptr <= buf + 12)
2150 png_chunk_benign_error(png_ptr, "invalid");
2154 png_debug(3, "Reading pCAL X0, X1, type, nparams, and units");
2155 X0 = png_get_int_32((png_bytep)buf+1);
2156 X1 = png_get_int_32((png_bytep)buf+5);
2161 png_debug(3, "Checking pCAL equation type and number of parameters");
2162 /* Check that we have the right number of parameters for known
2165 if ((type == PNG_EQUATION_LINEAR && nparams != 2) ||
2166 (type == PNG_EQUATION_BASE_E && nparams != 3) ||
2167 (type == PNG_EQUATION_ARBITRARY && nparams != 3) ||
2168 (type == PNG_EQUATION_HYPERBOLIC && nparams != 4))
2170 png_chunk_benign_error(png_ptr, "invalid parameter count");
2174 else if (type >= PNG_EQUATION_LAST)
2176 png_chunk_benign_error(png_ptr, "unrecognized equation type");
2179 for (buf = units; *buf; buf++)
2180 /* Empty loop to move past the units string. */ ;
2182 png_debug(3, "Allocating pCAL parameters array");
2184 params = png_voidcast(png_charpp, png_malloc_warn(png_ptr,
2185 nparams * (sizeof (png_charp))));
2189 png_chunk_benign_error(png_ptr, "out of memory");
2193 /* Get pointers to the start of each parameter string. */
2194 for (i = 0; i < nparams; i++)
2196 buf++; /* Skip the null string terminator from previous parameter. */
2198 png_debug1(3, "Reading pCAL parameter %d", i);
2200 for (params[i] = (png_charp)buf; buf <= endptr && *buf != 0; buf++)
2201 /* Empty loop to move past each parameter string */ ;
2203 /* Make sure we haven't run out of data yet */
2206 png_free(png_ptr, params);
2207 png_chunk_benign_error(png_ptr, "invalid data");
2212 png_set_pCAL(png_ptr, info_ptr, (png_charp)buffer, X0, X1, type, nparams,
2213 (png_charp)units, params);
2215 png_free(png_ptr, params);
2219 #ifdef PNG_READ_sCAL_SUPPORTED
2220 /* Read the sCAL chunk */
2222 png_handle_sCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2228 png_debug(1, "in png_handle_sCAL");
2230 if (!(png_ptr->mode & PNG_HAVE_IHDR))
2231 png_chunk_error(png_ptr, "missing IHDR");
2233 else if (png_ptr->mode & PNG_HAVE_IDAT)
2235 png_crc_finish(png_ptr, length);
2236 png_chunk_benign_error(png_ptr, "out of place");
2240 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sCAL))
2242 png_crc_finish(png_ptr, length);
2243 png_chunk_benign_error(png_ptr, "duplicate");
2247 /* Need unit type, width, \0, height: minimum 4 bytes */
2248 else if (length < 4)
2250 png_crc_finish(png_ptr, length);
2251 png_chunk_benign_error(png_ptr, "invalid");
2255 png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)",
2258 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
2262 png_chunk_benign_error(png_ptr, "out of memory");
2263 png_crc_finish(png_ptr, length);
2267 png_crc_read(png_ptr, buffer, length);
2268 buffer[length] = 0; /* Null terminate the last string */
2270 if (png_crc_finish(png_ptr, 0))
2273 /* Validate the unit. */
2274 if (buffer[0] != 1 && buffer[0] != 2)
2276 png_chunk_benign_error(png_ptr, "invalid unit");
2280 /* Validate the ASCII numbers, need two ASCII numbers separated by
2281 * a '\0' and they need to fit exactly in the chunk data.
2286 if (!png_check_fp_number((png_const_charp)buffer, length, &state, &i) ||
2287 i >= length || buffer[i++] != 0)
2288 png_chunk_benign_error(png_ptr, "bad width format");
2290 else if (!PNG_FP_IS_POSITIVE(state))
2291 png_chunk_benign_error(png_ptr, "non-positive width");
2295 png_size_t heighti = i;
2298 if (!png_check_fp_number((png_const_charp)buffer, length, &state, &i) ||
2300 png_chunk_benign_error(png_ptr, "bad height format");
2302 else if (!PNG_FP_IS_POSITIVE(state))
2303 png_chunk_benign_error(png_ptr, "non-positive height");
2306 /* This is the (only) success case. */
2307 png_set_sCAL_s(png_ptr, info_ptr, buffer[0],
2308 (png_charp)buffer+1, (png_charp)buffer+heighti);
2313 #ifdef PNG_READ_tIME_SUPPORTED
2315 png_handle_tIME(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2320 png_debug(1, "in png_handle_tIME");
2322 if (!(png_ptr->mode & PNG_HAVE_IHDR))
2323 png_chunk_error(png_ptr, "missing IHDR");
2325 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME))
2327 png_crc_finish(png_ptr, length);
2328 png_chunk_benign_error(png_ptr, "duplicate");
2332 if (png_ptr->mode & PNG_HAVE_IDAT)
2333 png_ptr->mode |= PNG_AFTER_IDAT;
2337 png_crc_finish(png_ptr, length);
2338 png_chunk_benign_error(png_ptr, "invalid");
2342 png_crc_read(png_ptr, buf, 7);
2344 if (png_crc_finish(png_ptr, 0))
2347 mod_time.second = buf[6];
2348 mod_time.minute = buf[5];
2349 mod_time.hour = buf[4];
2350 mod_time.day = buf[3];
2351 mod_time.month = buf[2];
2352 mod_time.year = png_get_uint_16(buf);
2354 png_set_tIME(png_ptr, info_ptr, &mod_time);
2358 #ifdef PNG_READ_tEXt_SUPPORTED
2359 /* Note: this does not properly handle chunks that are > 64K under DOS */
2361 png_handle_tEXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2367 png_uint_32 skip = 0;
2369 png_debug(1, "in png_handle_tEXt");
2371 #ifdef PNG_USER_LIMITS_SUPPORTED
2372 if (png_ptr->user_chunk_cache_max != 0)
2374 if (png_ptr->user_chunk_cache_max == 1)
2376 png_crc_finish(png_ptr, length);
2380 if (--png_ptr->user_chunk_cache_max == 1)
2382 png_crc_finish(png_ptr, length);
2383 png_chunk_benign_error(png_ptr, "no space in chunk cache");
2389 if (!(png_ptr->mode & PNG_HAVE_IHDR))
2390 png_chunk_error(png_ptr, "missing IHDR");
2392 if (png_ptr->mode & PNG_HAVE_IDAT)
2393 png_ptr->mode |= PNG_AFTER_IDAT;
2395 #ifdef PNG_MAX_MALLOC_64K
2396 if (length > 65535U)
2398 png_crc_finish(png_ptr, length);
2399 png_chunk_benign_error(png_ptr, "too large to fit in memory");
2404 buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/);
2408 png_chunk_benign_error(png_ptr, "out of memory");
2412 png_crc_read(png_ptr, buffer, length);
2414 if (png_crc_finish(png_ptr, skip))
2417 key = (png_charp)buffer;
2420 for (text = key; *text; text++)
2421 /* Empty loop to find end of key */ ;
2423 if (text != key + length)
2426 text_info.compression = PNG_TEXT_COMPRESSION_NONE;
2427 text_info.key = key;
2428 text_info.lang = NULL;
2429 text_info.lang_key = NULL;
2430 text_info.itxt_length = 0;
2431 text_info.text = text;
2432 text_info.text_length = strlen(text);
2434 if (png_set_text_2(png_ptr, info_ptr, &text_info, 1))
2435 png_warning(png_ptr, "Insufficient memory to process text chunk");
2439 #ifdef PNG_READ_zTXt_SUPPORTED
2440 /* Note: this does not correctly handle chunks that are > 64K under DOS */
2442 png_handle_zTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2444 png_const_charp errmsg = NULL;
2446 png_uint_32 keyword_length;
2448 png_debug(1, "in png_handle_zTXt");
2450 #ifdef PNG_USER_LIMITS_SUPPORTED
2451 if (png_ptr->user_chunk_cache_max != 0)
2453 if (png_ptr->user_chunk_cache_max == 1)
2455 png_crc_finish(png_ptr, length);
2459 if (--png_ptr->user_chunk_cache_max == 1)
2461 png_crc_finish(png_ptr, length);
2462 png_chunk_benign_error(png_ptr, "no space in chunk cache");
2468 if (!(png_ptr->mode & PNG_HAVE_IHDR))
2469 png_chunk_error(png_ptr, "missing IHDR");
2471 if (png_ptr->mode & PNG_HAVE_IDAT)
2472 png_ptr->mode |= PNG_AFTER_IDAT;
2474 buffer = png_read_buffer(png_ptr, length, 2/*silent*/);
2478 png_crc_finish(png_ptr, length);
2479 png_chunk_benign_error(png_ptr, "out of memory");
2483 png_crc_read(png_ptr, buffer, length);
2485 if (png_crc_finish(png_ptr, 0))
2488 /* TODO: also check that the keyword contents match the spec! */
2489 for (keyword_length = 0;
2490 keyword_length < length && buffer[keyword_length] != 0;
2492 /* Empty loop to find end of name */ ;
2494 if (keyword_length > 79 || keyword_length < 1)
2495 errmsg = "bad keyword";
2497 /* zTXt must have some LZ data after the keyword, although it may expand to
2498 * zero bytes; we need a '\0' at the end of the keyword, the compression type
2501 else if (keyword_length + 3 > length)
2502 errmsg = "truncated";
2504 else if (buffer[keyword_length+1] != PNG_COMPRESSION_TYPE_BASE)
2505 errmsg = "unknown compression type";
2509 png_alloc_size_t uncompressed_length = PNG_SIZE_MAX;
2511 /* TODO: at present png_decompress_chunk imposes a single application
2512 * level memory limit, this should be split to different values for iCCP
2515 if (png_decompress_chunk(png_ptr, length, keyword_length+2,
2516 &uncompressed_length, 1/*terminate*/) == Z_STREAM_END)
2520 /* It worked; png_ptr->read_buffer now looks like a tEXt chunk except
2521 * for the extra compression type byte and the fact that it isn't
2522 * necessarily '\0' terminated.
2524 buffer = png_ptr->read_buffer;
2525 buffer[uncompressed_length+(keyword_length+2)] = 0;
2527 text.compression = PNG_TEXT_COMPRESSION_zTXt;
2528 text.key = (png_charp)buffer;
2529 text.text = (png_charp)(buffer + keyword_length+2);
2530 text.text_length = uncompressed_length;
2531 text.itxt_length = 0;
2533 text.lang_key = NULL;
2535 if (png_set_text_2(png_ptr, info_ptr, &text, 1))
2536 errmsg = "insufficient memory";
2540 errmsg = png_ptr->zstream.msg;
2544 png_chunk_benign_error(png_ptr, errmsg);
2548 #ifdef PNG_READ_iTXt_SUPPORTED
2549 /* Note: this does not correctly handle chunks that are > 64K under DOS */
2551 png_handle_iTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2553 png_const_charp errmsg = NULL;
2555 png_uint_32 prefix_length;
2557 png_debug(1, "in png_handle_iTXt");
2559 #ifdef PNG_USER_LIMITS_SUPPORTED
2560 if (png_ptr->user_chunk_cache_max != 0)
2562 if (png_ptr->user_chunk_cache_max == 1)
2564 png_crc_finish(png_ptr, length);
2568 if (--png_ptr->user_chunk_cache_max == 1)
2570 png_crc_finish(png_ptr, length);
2571 png_chunk_benign_error(png_ptr, "no space in chunk cache");
2577 if (!(png_ptr->mode & PNG_HAVE_IHDR))
2578 png_chunk_error(png_ptr, "missing IHDR");
2580 if (png_ptr->mode & PNG_HAVE_IDAT)
2581 png_ptr->mode |= PNG_AFTER_IDAT;
2583 buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/);
2587 png_crc_finish(png_ptr, length);
2588 png_chunk_benign_error(png_ptr, "out of memory");
2592 png_crc_read(png_ptr, buffer, length);
2594 if (png_crc_finish(png_ptr, 0))
2597 /* First the keyword. */
2598 for (prefix_length=0;
2599 prefix_length < length && buffer[prefix_length] != 0;
2603 /* Perform a basic check on the keyword length here. */
2604 if (prefix_length > 79 || prefix_length < 1)
2605 errmsg = "bad keyword";
2607 /* Expect keyword, compression flag, compression type, language, translated
2608 * keyword (both may be empty but are 0 terminated) then the text, which may
2611 else if (prefix_length + 5 > length)
2612 errmsg = "truncated";
2614 else if (buffer[prefix_length+1] == 0 ||
2615 (buffer[prefix_length+1] == 1 &&
2616 buffer[prefix_length+2] == PNG_COMPRESSION_TYPE_BASE))
2618 int compressed = buffer[prefix_length+1] != 0;
2619 png_uint_32 language_offset, translated_keyword_offset;
2620 png_alloc_size_t uncompressed_length = 0;
2622 /* Now the language tag */
2624 language_offset = prefix_length;
2626 for (; prefix_length < length && buffer[prefix_length] != 0;
2630 /* WARNING: the length may be invalid here, this is checked below. */
2631 translated_keyword_offset = ++prefix_length;
2633 for (; prefix_length < length && buffer[prefix_length] != 0;
2637 /* prefix_length should now be at the trailing '\0' of the translated
2638 * keyword, but it may already be over the end. None of this arithmetic
2639 * can overflow because chunks are at most 2^31 bytes long, but on 16-bit
2640 * systems the available allocaton may overflow.
2644 if (!compressed && prefix_length <= length)
2645 uncompressed_length = length - prefix_length;
2647 else if (compressed && prefix_length < length)
2649 uncompressed_length = PNG_SIZE_MAX;
2651 /* TODO: at present png_decompress_chunk imposes a single application
2652 * level memory limit, this should be split to different values for
2653 * iCCP and text chunks.
2655 if (png_decompress_chunk(png_ptr, length, prefix_length,
2656 &uncompressed_length, 1/*terminate*/) == Z_STREAM_END)
2657 buffer = png_ptr->read_buffer;
2660 errmsg = png_ptr->zstream.msg;
2664 errmsg = "truncated";
2670 buffer[uncompressed_length+prefix_length] = 0;
2673 text.compression = PNG_ITXT_COMPRESSION_NONE;
2676 text.compression = PNG_ITXT_COMPRESSION_zTXt;
2678 text.key = (png_charp)buffer;
2679 text.lang = (png_charp)buffer + language_offset;
2680 text.lang_key = (png_charp)buffer + translated_keyword_offset;
2681 text.text = (png_charp)buffer + prefix_length;
2682 text.text_length = 0;
2683 text.itxt_length = uncompressed_length;
2685 if (png_set_text_2(png_ptr, info_ptr, &text, 1))
2686 errmsg = "insufficient memory";
2691 errmsg = "bad compression info";
2694 png_chunk_benign_error(png_ptr, errmsg);
2698 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
2699 /* Utility function for png_handle_unknown; set up png_ptr::unknown_chunk */
2701 png_cache_unknown_chunk(png_structrp png_ptr, png_uint_32 length)
2703 png_alloc_size_t limit = PNG_SIZE_MAX;
2705 if (png_ptr->unknown_chunk.data != NULL)
2707 png_free(png_ptr, png_ptr->unknown_chunk.data);
2708 png_ptr->unknown_chunk.data = NULL;
2711 # ifdef PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED
2712 if (png_ptr->user_chunk_malloc_max > 0 &&
2713 png_ptr->user_chunk_malloc_max < limit)
2714 limit = png_ptr->user_chunk_malloc_max;
2716 # elif PNG_USER_CHUNK_MALLOC_MAX > 0
2717 if (PNG_USER_CHUNK_MALLOC_MAX < limit)
2718 limit = PNG_USER_CHUNK_MALLOC_MAX;
2721 if (length <= limit)
2723 PNG_CSTRING_FROM_CHUNK(png_ptr->unknown_chunk.name, png_ptr->chunk_name);
2724 /* The following is safe because of the PNG_SIZE_MAX init above */
2725 png_ptr->unknown_chunk.size = (png_size_t)length/*SAFE*/;
2726 /* 'mode' is a flag array, only the bottom four bits matter here */
2727 png_ptr->unknown_chunk.location = (png_byte)png_ptr->mode/*SAFE*/;
2730 png_ptr->unknown_chunk.data = NULL;
2734 /* Do a 'warn' here - it is handled below. */
2735 png_ptr->unknown_chunk.data = png_voidcast(png_bytep,
2736 png_malloc_warn(png_ptr, length));
2740 if (png_ptr->unknown_chunk.data == NULL && length > 0)
2742 /* This is benign because we clean up correctly */
2743 png_crc_finish(png_ptr, length);
2744 png_chunk_benign_error(png_ptr, "unknown chunk exceeds memory limits");
2751 png_crc_read(png_ptr, png_ptr->unknown_chunk.data, length);
2752 png_crc_finish(png_ptr, 0);
2756 #endif /* PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */
2758 /* Handle an unknown, or known but disabled, chunk */
2760 png_handle_unknown(png_structrp png_ptr, png_inforp info_ptr,
2761 png_uint_32 length, int keep)
2763 int handled = 0; /* the chunk was handled */
2765 png_debug(1, "in png_handle_unknown");
2767 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
2768 /* NOTE: this code is based on the code in libpng-1.4.12 except for fixing
2769 * the bug which meant that setting a non-default behavior for a specific
2770 * chunk would be ignored (the default was always used unless a user
2771 * callback was installed).
2773 * 'keep' is the value from the png_chunk_unknown_handling, the setting for
2774 * this specific chunk_name, if PNG_HANDLE_AS_UNKNOWN_SUPPORTED, if not it
2775 * will always be PNG_HANDLE_CHUNK_AS_DEFAULT and it needs to be set here.
2776 * This is just an optimization to avoid multiple calls to the lookup
2779 # ifndef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
2780 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
2781 keep = png_chunk_unknown_handling(png_ptr, png_ptr->chunk_name);
2785 /* One of the following methods will read the chunk or skip it (at least one
2786 * of these is always defined because this is the only way to switch on
2787 * PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
2789 # ifdef PNG_READ_USER_CHUNKS_SUPPORTED
2790 /* The user callback takes precedence over the chunk keep value, but the
2791 * keep value is still required to validate a save of a critical chunk.
2793 if (png_ptr->read_user_chunk_fn != NULL)
2795 if (png_cache_unknown_chunk(png_ptr, length))
2797 /* Callback to user unknown chunk handler */
2798 int ret = (*(png_ptr->read_user_chunk_fn))(png_ptr,
2799 &png_ptr->unknown_chunk);
2802 * negative: An error occured, png_chunk_error will be called.
2803 * zero: The chunk was not handled, the chunk will be discarded
2804 * unless png_set_keep_unknown_chunks has been used to set
2805 * a 'keep' behavior for this particular chunk, in which
2806 * case that will be used. A critical chunk will cause an
2807 * error at this point unless it is to be saved.
2808 * positive: The chunk was handled, libpng will ignore/discard it.
2811 png_chunk_error(png_ptr, "error in user chunk");
2815 /* If the keep value is 'default' or 'never' override it, but
2816 * still error out on critical chunks unless the keep value is
2817 * 'always' While this is weird it is the behavior in 1.4.12.
2818 * A possible improvement would be to obey the value set for the
2819 * chunk, but this would be an API change that would probably
2820 * damage some applications.
2822 * The png_app_warning below catches the case that matters, where
2823 * the application has not set specific save or ignore for this
2824 * chunk or global save or ignore.
2826 if (keep < PNG_HANDLE_CHUNK_IF_SAFE)
2828 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
2829 if (png_ptr->unknown_default < PNG_HANDLE_CHUNK_IF_SAFE)
2831 png_chunk_warning(png_ptr, "Saving unknown chunk:");
2832 png_app_warning(png_ptr,
2833 "forcing save of an unhandled chunk;"
2834 " please call png_set_keep_unknown_chunks");
2835 /* with keep = PNG_HANDLE_CHUNK_IF_SAFE */
2838 keep = PNG_HANDLE_CHUNK_IF_SAFE;
2842 else /* chunk was handled */
2845 /* Critical chunks can be safely discarded at this point. */
2846 keep = PNG_HANDLE_CHUNK_NEVER;
2851 keep = PNG_HANDLE_CHUNK_NEVER; /* insufficient memory */
2855 /* Use the SAVE_UNKNOWN_CHUNKS code or skip the chunk */
2856 # endif /* PNG_READ_USER_CHUNKS_SUPPORTED */
2858 # ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
2860 /* keep is currently just the per-chunk setting, if there was no
2861 * setting change it to the global default now (not that this may
2862 * still be AS_DEFAULT) then obtain the cache of the chunk if required,
2863 * if not simply skip the chunk.
2865 if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT)
2866 keep = png_ptr->unknown_default;
2868 if (keep == PNG_HANDLE_CHUNK_ALWAYS ||
2869 (keep == PNG_HANDLE_CHUNK_IF_SAFE &&
2870 PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)))
2872 if (!png_cache_unknown_chunk(png_ptr, length))
2873 keep = PNG_HANDLE_CHUNK_NEVER;
2877 png_crc_finish(png_ptr, length);
2880 # ifndef PNG_READ_USER_CHUNKS_SUPPORTED
2881 # error no method to support READ_UNKNOWN_CHUNKS
2885 /* If here there is no read callback pointer set and no support is
2886 * compiled in to just save the unknown chunks, so simply skip this
2887 * chunk. If 'keep' is something other than AS_DEFAULT or NEVER then
2888 * the app has erroneously asked for unknown chunk saving when there
2891 if (keep > PNG_HANDLE_CHUNK_NEVER)
2892 png_app_error(png_ptr, "no unknown chunk support available");
2894 png_crc_finish(png_ptr, length);
2898 # ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
2899 /* Now store the chunk in the chunk list if appropriate, and if the limits
2902 if (keep == PNG_HANDLE_CHUNK_ALWAYS ||
2903 (keep == PNG_HANDLE_CHUNK_IF_SAFE &&
2904 PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)))
2906 # ifdef PNG_USER_LIMITS_SUPPORTED
2907 switch (png_ptr->user_chunk_cache_max)
2910 png_ptr->user_chunk_cache_max = 1;
2911 png_chunk_benign_error(png_ptr, "no space in chunk cache");
2914 /* NOTE: prior to 1.6.0 this case resulted in an unknown critical
2915 * chunk being skipped, now there will be a hard error below.
2919 default: /* not at limit */
2920 --(png_ptr->user_chunk_cache_max);
2922 case 0: /* no limit */
2923 # endif /* PNG_USER_LIMITS_SUPPORTED */
2924 /* Here when the limit isn't reached or when limits are compiled
2925 * out; store the chunk.
2927 png_set_unknown_chunks(png_ptr, info_ptr,
2928 &png_ptr->unknown_chunk, 1);
2930 # ifdef PNG_USER_LIMITS_SUPPORTED
2935 # else /* no store support: the chunk must be handled by the user callback */
2936 PNG_UNUSED(info_ptr)
2939 /* Regardless of the error handling below the cached data (if any) can be
2940 * freed now. Notice that the data is not freed if there is a png_error, but
2941 * it will be freed by destroy_read_struct.
2943 if (png_ptr->unknown_chunk.data != NULL)
2944 png_free(png_ptr, png_ptr->unknown_chunk.data);
2945 png_ptr->unknown_chunk.data = NULL;
2947 #else /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */
2948 /* There is no support to read an unknown chunk, so just skip it. */
2949 png_crc_finish(png_ptr, length);
2950 PNG_UNUSED(info_ptr)
2952 #endif /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */
2954 /* Check for unhandled critical chunks */
2955 if (!handled && PNG_CHUNK_CRITICAL(png_ptr->chunk_name))
2956 png_chunk_error(png_ptr, "unhandled critical chunk");
2959 /* This function is called to verify that a chunk name is valid.
2960 * This function can't have the "critical chunk check" incorporated
2961 * into it, since in the future we will need to be able to call user
2962 * functions to handle unknown critical chunks after we check that
2963 * the chunk name itself is valid.
2966 /* Bit hacking: the test for an invalid byte in the 4 byte chunk name is:
2968 * ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
2972 png_check_chunk_name(png_structrp png_ptr, png_uint_32 chunk_name)
2976 png_debug(1, "in png_check_chunk_name");
2978 for (i=1; i<=4; ++i)
2980 int c = chunk_name & 0xff;
2982 if (c < 65 || c > 122 || (c > 90 && c < 97))
2983 png_chunk_error(png_ptr, "invalid chunk type");
2989 /* Combines the row recently read in with the existing pixels in the row. This
2990 * routine takes care of alpha and transparency if requested. This routine also
2991 * handles the two methods of progressive display of interlaced images,
2992 * depending on the 'display' value; if 'display' is true then the whole row
2993 * (dp) is filled from the start by replicating the available pixels. If
2994 * 'display' is false only those pixels present in the pass are filled in.
2997 png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display)
2999 unsigned int pixel_depth = png_ptr->transformed_pixel_depth;
3000 png_const_bytep sp = png_ptr->row_buf + 1;
3001 png_uint_32 row_width = png_ptr->width;
3002 unsigned int pass = png_ptr->pass;
3003 png_bytep end_ptr = 0;
3004 png_byte end_byte = 0;
3005 unsigned int end_mask;
3007 png_debug(1, "in png_combine_row");
3009 /* Added in 1.5.6: it should not be possible to enter this routine until at
3010 * least one row has been read from the PNG data and transformed.
3012 if (pixel_depth == 0)
3013 png_error(png_ptr, "internal row logic error");
3015 /* Added in 1.5.4: the pixel depth should match the information returned by
3016 * any call to png_read_update_info at this point. Do not continue if we got
3019 if (png_ptr->info_rowbytes != 0 && png_ptr->info_rowbytes !=
3020 PNG_ROWBYTES(pixel_depth, row_width))
3021 png_error(png_ptr, "internal row size calculation error");
3023 /* Don't expect this to ever happen: */
3025 png_error(png_ptr, "internal row width error");
3027 /* Preserve the last byte in cases where only part of it will be overwritten,
3028 * the multiply below may overflow, we don't care because ANSI-C guarantees
3029 * we get the low bits.
3031 end_mask = (pixel_depth * row_width) & 7;
3034 /* end_ptr == NULL is a flag to say do nothing */
3035 end_ptr = dp + PNG_ROWBYTES(pixel_depth, row_width) - 1;
3036 end_byte = *end_ptr;
3037 # ifdef PNG_READ_PACKSWAP_SUPPORTED
3038 if (png_ptr->transformations & PNG_PACKSWAP) /* little-endian byte */
3039 end_mask = 0xff << end_mask;
3041 else /* big-endian byte */
3043 end_mask = 0xff >> end_mask;
3044 /* end_mask is now the bits to *keep* from the destination row */
3047 /* For non-interlaced images this reduces to a memcpy(). A memcpy()
3048 * will also happen if interlacing isn't supported or if the application
3049 * does not call png_set_interlace_handling(). In the latter cases the
3050 * caller just gets a sequence of the unexpanded rows from each interlace
3053 #ifdef PNG_READ_INTERLACING_SUPPORTED
3054 if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE) &&
3055 pass < 6 && (display == 0 ||
3056 /* The following copies everything for 'display' on passes 0, 2 and 4. */
3057 (display == 1 && (pass & 1) != 0)))
3059 /* Narrow images may have no bits in a pass; the caller should handle
3060 * this, but this test is cheap:
3062 if (row_width <= PNG_PASS_START_COL(pass))
3065 if (pixel_depth < 8)
3067 /* For pixel depths up to 4 bpp the 8-pixel mask can be expanded to fit
3068 * into 32 bits, then a single loop over the bytes using the four byte
3069 * values in the 32-bit mask can be used. For the 'display' option the
3070 * expanded mask may also not require any masking within a byte. To
3071 * make this work the PACKSWAP option must be taken into account - it
3072 * simply requires the pixels to be reversed in each byte.
3074 * The 'regular' case requires a mask for each of the first 6 passes,
3075 * the 'display' case does a copy for the even passes in the range
3076 * 0..6. This has already been handled in the test above.
3078 * The masks are arranged as four bytes with the first byte to use in
3079 * the lowest bits (little-endian) regardless of the order (PACKSWAP or
3080 * not) of the pixels in each byte.
3082 * NOTE: the whole of this logic depends on the caller of this function
3083 * only calling it on rows appropriate to the pass. This function only
3084 * understands the 'x' logic; the 'y' logic is handled by the caller.
3086 * The following defines allow generation of compile time constant bit
3087 * masks for each pixel depth and each possibility of swapped or not
3088 * swapped bytes. Pass 'p' is in the range 0..6; 'x', a pixel index,
3089 * is in the range 0..7; and the result is 1 if the pixel is to be
3090 * copied in the pass, 0 if not. 'S' is for the sparkle method, 'B'
3091 * for the block method.
3093 * With some compilers a compile time expression of the general form:
3095 * (shift >= 32) ? (a >> (shift-32)) : (b >> shift)
3097 * Produces warnings with values of 'shift' in the range 33 to 63
3098 * because the right hand side of the ?: expression is evaluated by
3099 * the compiler even though it isn't used. Microsoft Visual C (various
3100 * versions) and the Intel C compiler are known to do this. To avoid
3101 * this the following macros are used in 1.5.6. This is a temporary
3102 * solution to avoid destabilizing the code during the release process.
3104 # if PNG_USE_COMPILE_TIME_MASKS
3105 # define PNG_LSR(x,s) ((x)>>((s) & 0x1f))
3106 # define PNG_LSL(x,s) ((x)<<((s) & 0x1f))
3108 # define PNG_LSR(x,s) ((x)>>(s))
3109 # define PNG_LSL(x,s) ((x)<<(s))
3111 # define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\
3112 PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1)
3113 # define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\
3114 PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1)
3116 /* Return a mask for pass 'p' pixel 'x' at depth 'd'. The mask is
3117 * little endian - the first pixel is at bit 0 - however the extra
3118 * parameter 's' can be set to cause the mask position to be swapped
3119 * within each byte, to match the PNG format. This is done by XOR of
3120 * the shift with 7, 6 or 4 for bit depths 1, 2 and 4.
3122 # define PIXEL_MASK(p,x,d,s) \
3123 (PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0))))
3125 /* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask.
3127 # define S_MASKx(p,x,d,s) (S_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
3128 # define B_MASKx(p,x,d,s) (B_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
3130 /* Combine 8 of these to get the full mask. For the 1-bpp and 2-bpp
3131 * cases the result needs replicating, for the 4-bpp case the above
3132 * generates a full 32 bits.
3134 # define MASK_EXPAND(m,d) ((m)*((d)==1?0x01010101:((d)==2?0x00010001:1)))
3136 # define S_MASK(p,d,s) MASK_EXPAND(S_MASKx(p,0,d,s) + S_MASKx(p,1,d,s) +\
3137 S_MASKx(p,2,d,s) + S_MASKx(p,3,d,s) + S_MASKx(p,4,d,s) +\
3138 S_MASKx(p,5,d,s) + S_MASKx(p,6,d,s) + S_MASKx(p,7,d,s), d)
3140 # define B_MASK(p,d,s) MASK_EXPAND(B_MASKx(p,0,d,s) + B_MASKx(p,1,d,s) +\
3141 B_MASKx(p,2,d,s) + B_MASKx(p,3,d,s) + B_MASKx(p,4,d,s) +\
3142 B_MASKx(p,5,d,s) + B_MASKx(p,6,d,s) + B_MASKx(p,7,d,s), d)
3144 #if PNG_USE_COMPILE_TIME_MASKS
3145 /* Utility macros to construct all the masks for a depth/swap
3146 * combination. The 's' parameter says whether the format is PNG
3147 * (big endian bytes) or not. Only the three odd-numbered passes are
3148 * required for the display/block algorithm.
3150 # define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\
3151 S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) }
3153 # define B_MASKS(d,s) { B_MASK(1,d,s), S_MASK(3,d,s), S_MASK(5,d,s) }
3155 # define DEPTH_INDEX(d) ((d)==1?0:((d)==2?1:2))
3157 /* Hence the pre-compiled masks indexed by PACKSWAP (or not), depth and
3160 static PNG_CONST png_uint_32 row_mask[2/*PACKSWAP*/][3/*depth*/][6] =
3162 /* Little-endian byte masks for PACKSWAP */
3163 { S_MASKS(1,0), S_MASKS(2,0), S_MASKS(4,0) },
3164 /* Normal (big-endian byte) masks - PNG format */
3165 { S_MASKS(1,1), S_MASKS(2,1), S_MASKS(4,1) }
3168 /* display_mask has only three entries for the odd passes, so index by
3171 static PNG_CONST png_uint_32 display_mask[2][3][3] =
3173 /* Little-endian byte masks for PACKSWAP */
3174 { B_MASKS(1,0), B_MASKS(2,0), B_MASKS(4,0) },
3175 /* Normal (big-endian byte) masks - PNG format */
3176 { B_MASKS(1,1), B_MASKS(2,1), B_MASKS(4,1) }
3179 # define MASK(pass,depth,display,png)\
3180 ((display)?display_mask[png][DEPTH_INDEX(depth)][pass>>1]:\
3181 row_mask[png][DEPTH_INDEX(depth)][pass])
3183 #else /* !PNG_USE_COMPILE_TIME_MASKS */
3184 /* This is the runtime alternative: it seems unlikely that this will
3185 * ever be either smaller or faster than the compile time approach.
3187 # define MASK(pass,depth,display,png)\
3188 ((display)?B_MASK(pass,depth,png):S_MASK(pass,depth,png))
3189 #endif /* !PNG_USE_COMPILE_TIME_MASKS */
3191 /* Use the appropriate mask to copy the required bits. In some cases
3192 * the byte mask will be 0 or 0xff, optimize these cases. row_width is
3193 * the number of pixels, but the code copies bytes, so it is necessary
3194 * to special case the end.
3196 png_uint_32 pixels_per_byte = 8 / pixel_depth;
3199 # ifdef PNG_READ_PACKSWAP_SUPPORTED
3200 if (png_ptr->transformations & PNG_PACKSWAP)
3201 mask = MASK(pass, pixel_depth, display, 0);
3205 mask = MASK(pass, pixel_depth, display, 1);
3211 /* It doesn't matter in the following if png_uint_32 has more than
3212 * 32 bits because the high bits always match those in m<<24; it is,
3213 * however, essential to use OR here, not +, because of this.
3216 mask = (m >> 8) | (m << 24); /* rotate right to good compilers */
3219 if (m != 0) /* something to copy */
3222 *dp = (png_byte)((*dp & ~m) | (*sp & m));
3227 /* NOTE: this may overwrite the last byte with garbage if the image
3228 * is not an exact number of bytes wide; libpng has always done
3231 if (row_width <= pixels_per_byte)
3232 break; /* May need to restore part of the last byte */
3234 row_width -= pixels_per_byte;
3240 else /* pixel_depth >= 8 */
3242 unsigned int bytes_to_copy, bytes_to_jump;
3244 /* Validate the depth - it must be a multiple of 8 */
3245 if (pixel_depth & 7)
3246 png_error(png_ptr, "invalid user transform pixel depth");
3248 pixel_depth >>= 3; /* now in bytes */
3249 row_width *= pixel_depth;
3251 /* Regardless of pass number the Adam 7 interlace always results in a
3252 * fixed number of pixels to copy then to skip. There may be a
3253 * different number of pixels to skip at the start though.
3256 unsigned int offset = PNG_PASS_START_COL(pass) * pixel_depth;
3258 row_width -= offset;
3263 /* Work out the bytes to copy. */
3266 /* When doing the 'block' algorithm the pixel in the pass gets
3267 * replicated to adjacent pixels. This is why the even (0,2,4,6)
3268 * passes are skipped above - the entire expanded row is copied.
3270 bytes_to_copy = (1<<((6-pass)>>1)) * pixel_depth;
3272 /* But don't allow this number to exceed the actual row width. */
3273 if (bytes_to_copy > row_width)
3274 bytes_to_copy = row_width;
3277 else /* normal row; Adam7 only ever gives us one pixel to copy. */
3278 bytes_to_copy = pixel_depth;
3280 /* In Adam7 there is a constant offset between where the pixels go. */
3281 bytes_to_jump = PNG_PASS_COL_OFFSET(pass) * pixel_depth;
3283 /* And simply copy these bytes. Some optimization is possible here,
3284 * depending on the value of 'bytes_to_copy'. Special case the low
3285 * byte counts, which we know to be frequent.
3287 * Notice that these cases all 'return' rather than 'break' - this
3288 * avoids an unnecessary test on whether to restore the last byte
3291 switch (bytes_to_copy)
3298 if (row_width <= bytes_to_jump)
3301 dp += bytes_to_jump;
3302 sp += bytes_to_jump;
3303 row_width -= bytes_to_jump;
3307 /* There is a possibility of a partial copy at the end here; this
3308 * slows the code down somewhat.
3312 dp[0] = sp[0], dp[1] = sp[1];
3314 if (row_width <= bytes_to_jump)
3317 sp += bytes_to_jump;
3318 dp += bytes_to_jump;
3319 row_width -= bytes_to_jump;
3321 while (row_width > 1);
3323 /* And there can only be one byte left at this point: */
3328 /* This can only be the RGB case, so each copy is exactly one
3329 * pixel and it is not necessary to check for a partial copy.
3333 dp[0] = sp[0], dp[1] = sp[1], dp[2] = sp[2];
3335 if (row_width <= bytes_to_jump)
3338 sp += bytes_to_jump;
3339 dp += bytes_to_jump;
3340 row_width -= bytes_to_jump;
3344 #if PNG_ALIGN_TYPE != PNG_ALIGN_NONE
3345 /* Check for double byte alignment and, if possible, use a
3346 * 16-bit copy. Don't attempt this for narrow images - ones that
3347 * are less than an interlace panel wide. Don't attempt it for
3348 * wide bytes_to_copy either - use the memcpy there.
3350 if (bytes_to_copy < 16 /*else use memcpy*/ &&
3351 png_isaligned(dp, png_uint_16) &&
3352 png_isaligned(sp, png_uint_16) &&
3353 bytes_to_copy % (sizeof (png_uint_16)) == 0 &&
3354 bytes_to_jump % (sizeof (png_uint_16)) == 0)
3356 /* Everything is aligned for png_uint_16 copies, but try for
3357 * png_uint_32 first.
3359 if (png_isaligned(dp, png_uint_32) &&
3360 png_isaligned(sp, png_uint_32) &&
3361 bytes_to_copy % (sizeof (png_uint_32)) == 0 &&
3362 bytes_to_jump % (sizeof (png_uint_32)) == 0)
3364 png_uint_32p dp32 = png_aligncast(png_uint_32p,dp);
3365 png_const_uint_32p sp32 = png_aligncastconst(
3366 png_const_uint_32p, sp);
3367 size_t skip = (bytes_to_jump-bytes_to_copy) /
3368 (sizeof (png_uint_32));
3372 size_t c = bytes_to_copy;
3376 c -= (sizeof (png_uint_32));
3380 if (row_width <= bytes_to_jump)
3385 row_width -= bytes_to_jump;
3387 while (bytes_to_copy <= row_width);
3389 /* Get to here when the row_width truncates the final copy.
3390 * There will be 1-3 bytes left to copy, so don't try the
3391 * 16-bit loop below.
3393 dp = (png_bytep)dp32;
3394 sp = (png_const_bytep)sp32;
3397 while (--row_width > 0);
3401 /* Else do it in 16-bit quantities, but only if the size is
3406 png_uint_16p dp16 = png_aligncast(png_uint_16p, dp);
3407 png_const_uint_16p sp16 = png_aligncastconst(
3408 png_const_uint_16p, sp);
3409 size_t skip = (bytes_to_jump-bytes_to_copy) /
3410 (sizeof (png_uint_16));
3414 size_t c = bytes_to_copy;
3418 c -= (sizeof (png_uint_16));
3422 if (row_width <= bytes_to_jump)
3427 row_width -= bytes_to_jump;
3429 while (bytes_to_copy <= row_width);
3431 /* End of row - 1 byte left, bytes_to_copy > row_width: */
3432 dp = (png_bytep)dp16;
3433 sp = (png_const_bytep)sp16;
3436 while (--row_width > 0);
3440 #endif /* PNG_ALIGN_ code */
3442 /* The true default - use a memcpy: */
3445 memcpy(dp, sp, bytes_to_copy);
3447 if (row_width <= bytes_to_jump)
3450 sp += bytes_to_jump;
3451 dp += bytes_to_jump;
3452 row_width -= bytes_to_jump;
3453 if (bytes_to_copy > row_width)
3454 bytes_to_copy = row_width;
3459 } /* pixel_depth >= 8 */
3461 /* Here if pixel_depth < 8 to check 'end_ptr' below. */
3466 /* If here then the switch above wasn't used so just memcpy the whole row
3467 * from the temporary row buffer (notice that this overwrites the end of the
3468 * destination row if it is a partial byte.)
3470 memcpy(dp, sp, PNG_ROWBYTES(pixel_depth, row_width));
3472 /* Restore the overwritten bits from the last byte if necessary. */
3473 if (end_ptr != NULL)
3474 *end_ptr = (png_byte)((end_byte & end_mask) | (*end_ptr & ~end_mask));
3477 #ifdef PNG_READ_INTERLACING_SUPPORTED
3479 png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
3480 png_uint_32 transformations /* Because these may affect the byte layout */)
3482 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
3483 /* Offset to next interlace block */
3484 static PNG_CONST int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
3486 png_debug(1, "in png_do_read_interlace");
3487 if (row != NULL && row_info != NULL)
3489 png_uint_32 final_width;
3491 final_width = row_info->width * png_pass_inc[pass];
3493 switch (row_info->pixel_depth)
3497 png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 3);
3498 png_bytep dp = row + (png_size_t)((final_width - 1) >> 3);
3500 int s_start, s_end, s_inc;
3501 int jstop = png_pass_inc[pass];
3506 #ifdef PNG_READ_PACKSWAP_SUPPORTED
3507 if (transformations & PNG_PACKSWAP)
3509 sshift = (int)((row_info->width + 7) & 0x07);
3510 dshift = (int)((final_width + 7) & 0x07);
3519 sshift = 7 - (int)((row_info->width + 7) & 0x07);
3520 dshift = 7 - (int)((final_width + 7) & 0x07);
3526 for (i = 0; i < row_info->width; i++)
3528 v = (png_byte)((*sp >> sshift) & 0x01);
3529 for (j = 0; j < jstop; j++)
3531 unsigned int tmp = *dp & (0x7f7f >> (7 - dshift));
3533 *dp = (png_byte)(tmp & 0xff);
3535 if (dshift == s_end)
3545 if (sshift == s_end)
3559 png_bytep sp = row + (png_uint_32)((row_info->width - 1) >> 2);
3560 png_bytep dp = row + (png_uint_32)((final_width - 1) >> 2);
3562 int s_start, s_end, s_inc;
3563 int jstop = png_pass_inc[pass];
3566 #ifdef PNG_READ_PACKSWAP_SUPPORTED
3567 if (transformations & PNG_PACKSWAP)
3569 sshift = (int)(((row_info->width + 3) & 0x03) << 1);
3570 dshift = (int)(((final_width + 3) & 0x03) << 1);
3579 sshift = (int)((3 - ((row_info->width + 3) & 0x03)) << 1);
3580 dshift = (int)((3 - ((final_width + 3) & 0x03)) << 1);
3586 for (i = 0; i < row_info->width; i++)
3591 v = (png_byte)((*sp >> sshift) & 0x03);
3592 for (j = 0; j < jstop; j++)
3594 unsigned int tmp = *dp & (0x3f3f >> (6 - dshift));
3596 *dp = (png_byte)(tmp & 0xff);
3598 if (dshift == s_end)
3608 if (sshift == s_end)
3622 png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 1);
3623 png_bytep dp = row + (png_size_t)((final_width - 1) >> 1);
3625 int s_start, s_end, s_inc;
3627 int jstop = png_pass_inc[pass];
3629 #ifdef PNG_READ_PACKSWAP_SUPPORTED
3630 if (transformations & PNG_PACKSWAP)
3632 sshift = (int)(((row_info->width + 1) & 0x01) << 2);
3633 dshift = (int)(((final_width + 1) & 0x01) << 2);
3642 sshift = (int)((1 - ((row_info->width + 1) & 0x01)) << 2);
3643 dshift = (int)((1 - ((final_width + 1) & 0x01)) << 2);
3649 for (i = 0; i < row_info->width; i++)
3651 png_byte v = (png_byte)((*sp >> sshift) & 0x0f);
3654 for (j = 0; j < jstop; j++)
3656 unsigned int tmp = *dp & (0xf0f >> (4 - dshift));
3658 *dp = (png_byte)(tmp & 0xff);
3660 if (dshift == s_end)
3670 if (sshift == s_end)
3684 png_size_t pixel_bytes = (row_info->pixel_depth >> 3);
3686 png_bytep sp = row + (png_size_t)(row_info->width - 1)
3689 png_bytep dp = row + (png_size_t)(final_width - 1) * pixel_bytes;
3691 int jstop = png_pass_inc[pass];
3694 for (i = 0; i < row_info->width; i++)
3696 png_byte v[8]; /* SAFE; pixel_depth does not exceed 64 */
3699 memcpy(v, sp, pixel_bytes);
3701 for (j = 0; j < jstop; j++)
3703 memcpy(dp, v, pixel_bytes);
3713 row_info->width = final_width;
3714 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, final_width);
3716 #ifndef PNG_READ_PACKSWAP_SUPPORTED
3717 PNG_UNUSED(transformations) /* Silence compiler warning */
3720 #endif /* PNG_READ_INTERLACING_SUPPORTED */
3723 png_read_filter_row_sub(png_row_infop row_info, png_bytep row,
3724 png_const_bytep prev_row)
3727 png_size_t istop = row_info->rowbytes;
3728 unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
3729 png_bytep rp = row + bpp;
3731 PNG_UNUSED(prev_row)
3733 for (i = bpp; i < istop; i++)
3735 *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
3741 png_read_filter_row_up(png_row_infop row_info, png_bytep row,
3742 png_const_bytep prev_row)
3745 png_size_t istop = row_info->rowbytes;
3747 png_const_bytep pp = prev_row;
3749 for (i = 0; i < istop; i++)
3751 *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
3757 png_read_filter_row_avg(png_row_infop row_info, png_bytep row,
3758 png_const_bytep prev_row)
3762 png_const_bytep pp = prev_row;
3763 unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
3764 png_size_t istop = row_info->rowbytes - bpp;
3766 for (i = 0; i < bpp; i++)
3768 *rp = (png_byte)(((int)(*rp) +
3769 ((int)(*pp++) / 2 )) & 0xff);
3774 for (i = 0; i < istop; i++)
3776 *rp = (png_byte)(((int)(*rp) +
3777 (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
3784 png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info, png_bytep row,
3785 png_const_bytep prev_row)
3787 png_bytep rp_end = row + row_info->rowbytes;
3790 /* First pixel/byte */
3793 *row++ = (png_byte)a;
3796 while (row < rp_end)
3798 int b, pa, pb, pc, p;
3800 a &= 0xff; /* From previous iteration or start */
3811 pa = p < 0 ? -p : p;
3812 pb = pc < 0 ? -pc : pc;
3813 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
3816 /* Find the best predictor, the least of pa, pb, pc favoring the earlier
3817 * ones in the case of a tie.
3819 if (pb < pa) pa = pb, a = b;
3822 /* Calculate the current pixel in a, and move the previous row pixel to c
3823 * for the next time round the loop
3827 *row++ = (png_byte)a;
3832 png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row,
3833 png_const_bytep prev_row)
3835 int bpp = (row_info->pixel_depth + 7) >> 3;
3836 png_bytep rp_end = row + bpp;
3838 /* Process the first pixel in the row completely (this is the same as 'up'
3839 * because there is only one candidate predictor for the first row).
3841 while (row < rp_end)
3843 int a = *row + *prev_row++;
3844 *row++ = (png_byte)a;
3848 rp_end += row_info->rowbytes - bpp;
3850 while (row < rp_end)
3852 int a, b, c, pa, pb, pc, p;
3854 c = *(prev_row - bpp);
3866 pa = p < 0 ? -p : p;
3867 pb = pc < 0 ? -pc : pc;
3868 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
3871 if (pb < pa) pa = pb, a = b;
3876 *row++ = (png_byte)a;
3881 png_init_filter_functions(png_structrp pp)
3882 /* This function is called once for every PNG image (except for PNG images
3883 * that only use PNG_FILTER_VALUE_NONE for all rows) to set the
3884 * implementations required to reverse the filtering of PNG rows. Reversing
3885 * the filter is the first transformation performed on the row data. It is
3886 * performed in place, therefore an implementation can be selected based on
3887 * the image pixel format. If the implementation depends on image width then
3888 * take care to ensure that it works correctly if the image is interlaced -
3889 * interlacing causes the actual row width to vary.
3892 unsigned int bpp = (pp->pixel_depth + 7) >> 3;
3894 pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub;
3895 pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up;
3896 pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg;
3898 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
3899 png_read_filter_row_paeth_1byte_pixel;
3901 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
3902 png_read_filter_row_paeth_multibyte_pixel;
3904 #ifdef PNG_FILTER_OPTIMIZATIONS
3905 /* To use this define PNG_FILTER_OPTIMIZATIONS as the name of a function to
3906 * call to install hardware optimizations for the above functions; simply
3907 * replace whatever elements of the pp->read_filter[] array with a hardware
3908 * specific (or, for that matter, generic) optimization.
3910 * To see an example of this examine what configure.ac does when
3911 * --enable-arm-neon is specified on the command line.
3913 PNG_FILTER_OPTIMIZATIONS(pp, bpp);
3918 png_read_filter_row(png_structrp pp, png_row_infop row_info, png_bytep row,
3919 png_const_bytep prev_row, int filter)
3921 /* OPTIMIZATION: DO NOT MODIFY THIS FUNCTION, instead #define
3922 * PNG_FILTER_OPTIMIZATIONS to a function that overrides the generic
3923 * implementations. See png_init_filter_functions above.
3925 if (filter > PNG_FILTER_VALUE_NONE && filter < PNG_FILTER_VALUE_LAST)
3927 if (pp->read_filter[0] == NULL)
3928 png_init_filter_functions(pp);
3930 pp->read_filter[filter-1](row_info, row, prev_row);
3934 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
3936 png_read_IDAT_data(png_structrp png_ptr, png_bytep output,
3937 png_alloc_size_t avail_out)
3939 /* Loop reading IDATs and decompressing the result into output[avail_out] */
3940 png_ptr->zstream.next_out = output;
3941 png_ptr->zstream.avail_out = 0; /* safety: set below */
3949 png_byte tmpbuf[PNG_INFLATE_BUF_SIZE];
3951 if (png_ptr->zstream.avail_in == 0)
3956 while (png_ptr->idat_size == 0)
3958 png_crc_finish(png_ptr, 0);
3960 png_ptr->idat_size = png_read_chunk_header(png_ptr);
3961 /* This is an error even in the 'check' case because the code just
3962 * consumed a non-IDAT header.
3964 if (png_ptr->chunk_name != png_IDAT)
3965 png_error(png_ptr, "Not enough image data");
3968 avail_in = png_ptr->IDAT_read_size;
3970 if (avail_in > png_ptr->idat_size)
3971 avail_in = (uInt)png_ptr->idat_size;
3973 /* A PNG with a gradually increasing IDAT size will defeat this attempt
3974 * to minimize memory usage by causing lots of re-allocs, but
3975 * realistically doing IDAT_read_size re-allocs is not likely to be a
3978 buffer = png_read_buffer(png_ptr, avail_in, 0/*error*/);
3980 png_crc_read(png_ptr, buffer, avail_in);
3981 png_ptr->idat_size -= avail_in;
3983 png_ptr->zstream.next_in = buffer;
3984 png_ptr->zstream.avail_in = avail_in;
3987 /* And set up the output side. */
3988 if (output != NULL) /* standard read */
3990 uInt out = ZLIB_IO_MAX;
3992 if (out > avail_out)
3993 out = (uInt)avail_out;
3996 png_ptr->zstream.avail_out = out;
3999 else /* after last row, checking for end */
4001 png_ptr->zstream.next_out = tmpbuf;
4002 png_ptr->zstream.avail_out = (sizeof tmpbuf);
4005 /* Use NO_FLUSH; this gives zlib the maximum opportunity to optimize the
4006 * process. If the LZ stream is truncated the sequential reader will
4007 * terminally damage the stream, above, by reading the chunk header of the
4008 * following chunk (it then exits with png_error).
4010 * TODO: deal more elegantly with truncated IDAT lists.
4012 ret = inflate(&png_ptr->zstream, Z_NO_FLUSH);
4014 /* Take the unconsumed output back. */
4016 avail_out += png_ptr->zstream.avail_out;
4018 else /* avail_out counts the extra bytes */
4019 avail_out += (sizeof tmpbuf) - png_ptr->zstream.avail_out;
4021 png_ptr->zstream.avail_out = 0;
4023 if (ret == Z_STREAM_END)
4025 /* Do this for safety; we won't read any more into this row. */
4026 png_ptr->zstream.next_out = NULL;
4028 png_ptr->mode |= PNG_AFTER_IDAT;
4029 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
4031 if (png_ptr->zstream.avail_in > 0 || png_ptr->idat_size > 0)
4032 png_chunk_benign_error(png_ptr, "Extra compressed data");
4038 png_zstream_error(png_ptr, ret);
4041 png_chunk_error(png_ptr, png_ptr->zstream.msg);
4045 png_chunk_benign_error(png_ptr, png_ptr->zstream.msg);
4049 } while (avail_out > 0);
4053 /* The stream ended before the image; this is the same as too few IDATs so
4054 * should be handled the same way.
4057 png_error(png_ptr, "Not enough image data");
4059 else /* the deflate stream contained extra data */
4060 png_chunk_benign_error(png_ptr, "Too much image data");
4065 png_read_finish_IDAT(png_structrp png_ptr)
4067 /* We don't need any more data and the stream should have ended, however the
4068 * LZ end code may actually not have been processed. In this case we must
4069 * read it otherwise stray unread IDAT data or, more likely, an IDAT chunk
4070 * may still remain to be consumed.
4072 if (!(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED))
4074 /* The NULL causes png_read_IDAT_data to swallow any remaining bytes in
4075 * the compressed stream, but the stream may be damaged too, so even after
4076 * this call we may need to terminate the zstream ownership.
4078 png_read_IDAT_data(png_ptr, NULL, 0);
4079 png_ptr->zstream.next_out = NULL; /* safety */
4081 /* Now clear everything out for safety; the following may not have been
4084 if (!(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED))
4086 png_ptr->mode |= PNG_AFTER_IDAT;
4087 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
4091 /* If the zstream has not been released do it now *and* terminate the reading
4092 * of the final IDAT chunk.
4094 if (png_ptr->zowner == png_IDAT)
4096 /* Always do this; the pointers otherwise point into the read buffer. */
4097 png_ptr->zstream.next_in = NULL;
4098 png_ptr->zstream.avail_in = 0;
4100 /* Now we no longer own the zstream. */
4101 png_ptr->zowner = 0;
4103 /* The slightly weird semantics of the sequential IDAT reading is that we
4104 * are always in or at the end of an IDAT chunk, so we always need to do a
4105 * crc_finish here. If idat_size is non-zero we also need to read the
4106 * spurious bytes at the end of the chunk now.
4108 (void)png_crc_finish(png_ptr, png_ptr->idat_size);
4113 png_read_finish_row(png_structrp png_ptr)
4115 #ifdef PNG_READ_INTERLACING_SUPPORTED
4116 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
4118 /* Start of interlace block */
4119 static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
4121 /* Offset to next interlace block */
4122 static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
4124 /* Start of interlace block in the y direction */
4125 static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
4127 /* Offset to next interlace block in the y direction */
4128 static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
4129 #endif /* PNG_READ_INTERLACING_SUPPORTED */
4131 png_debug(1, "in png_read_finish_row");
4132 png_ptr->row_number++;
4133 if (png_ptr->row_number < png_ptr->num_rows)
4136 #ifdef PNG_READ_INTERLACING_SUPPORTED
4137 if (png_ptr->interlaced)
4139 png_ptr->row_number = 0;
4141 /* TO DO: don't do this if prev_row isn't needed (requires
4142 * read-ahead of the next row's filter byte.
4144 memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
4150 if (png_ptr->pass >= 7)
4153 png_ptr->iwidth = (png_ptr->width +
4154 png_pass_inc[png_ptr->pass] - 1 -
4155 png_pass_start[png_ptr->pass]) /
4156 png_pass_inc[png_ptr->pass];
4158 if (!(png_ptr->transformations & PNG_INTERLACE))
4160 png_ptr->num_rows = (png_ptr->height +
4161 png_pass_yinc[png_ptr->pass] - 1 -
4162 png_pass_ystart[png_ptr->pass]) /
4163 png_pass_yinc[png_ptr->pass];
4166 else /* if (png_ptr->transformations & PNG_INTERLACE) */
4167 break; /* libpng deinterlacing sees every row */
4169 } while (png_ptr->num_rows == 0 || png_ptr->iwidth == 0);
4171 if (png_ptr->pass < 7)
4174 #endif /* PNG_READ_INTERLACING_SUPPORTED */
4176 /* Here after at the end of the last row of the last pass. */
4177 png_read_finish_IDAT(png_ptr);
4179 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
4182 png_read_start_row(png_structrp png_ptr)
4184 #ifdef PNG_READ_INTERLACING_SUPPORTED
4185 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
4187 /* Start of interlace block */
4188 static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
4190 /* Offset to next interlace block */
4191 static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
4193 /* Start of interlace block in the y direction */
4194 static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
4196 /* Offset to next interlace block in the y direction */
4197 static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
4200 int max_pixel_depth;
4201 png_size_t row_bytes;
4203 png_debug(1, "in png_read_start_row");
4205 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
4206 png_init_read_transformations(png_ptr);
4208 #ifdef PNG_READ_INTERLACING_SUPPORTED
4209 if (png_ptr->interlaced)
4211 if (!(png_ptr->transformations & PNG_INTERLACE))
4212 png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
4213 png_pass_ystart[0]) / png_pass_yinc[0];
4216 png_ptr->num_rows = png_ptr->height;
4218 png_ptr->iwidth = (png_ptr->width +
4219 png_pass_inc[png_ptr->pass] - 1 -
4220 png_pass_start[png_ptr->pass]) /
4221 png_pass_inc[png_ptr->pass];
4225 #endif /* PNG_READ_INTERLACING_SUPPORTED */
4227 png_ptr->num_rows = png_ptr->height;
4228 png_ptr->iwidth = png_ptr->width;
4231 max_pixel_depth = png_ptr->pixel_depth;
4233 /* WARNING: * png_read_transform_info (pngrtran.c) performs a simpliar set of
4234 * calculations to calculate the final pixel depth, then
4235 * png_do_read_transforms actually does the transforms. This means that the
4236 * code which effectively calculates this value is actually repeated in three
4237 * separate places. They must all match. Innocent changes to the order of
4238 * transformations can and will break libpng in a way that causes memory
4243 #ifdef PNG_READ_PACK_SUPPORTED
4244 if ((png_ptr->transformations & PNG_PACK) && png_ptr->bit_depth < 8)
4245 max_pixel_depth = 8;
4248 #ifdef PNG_READ_EXPAND_SUPPORTED
4249 if (png_ptr->transformations & PNG_EXPAND)
4251 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
4253 if (png_ptr->num_trans)
4254 max_pixel_depth = 32;
4257 max_pixel_depth = 24;
4260 else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
4262 if (max_pixel_depth < 8)
4263 max_pixel_depth = 8;
4265 if (png_ptr->num_trans)
4266 max_pixel_depth *= 2;
4269 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
4271 if (png_ptr->num_trans)
4273 max_pixel_depth *= 4;
4274 max_pixel_depth /= 3;
4280 #ifdef PNG_READ_EXPAND_16_SUPPORTED
4281 if (png_ptr->transformations & PNG_EXPAND_16)
4283 # ifdef PNG_READ_EXPAND_SUPPORTED
4284 /* In fact it is an error if it isn't supported, but checking is
4287 if (png_ptr->transformations & PNG_EXPAND)
4289 if (png_ptr->bit_depth < 16)
4290 max_pixel_depth *= 2;
4294 png_ptr->transformations &= ~PNG_EXPAND_16;
4298 #ifdef PNG_READ_FILLER_SUPPORTED
4299 if (png_ptr->transformations & (PNG_FILLER))
4301 if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
4303 if (max_pixel_depth <= 8)
4304 max_pixel_depth = 16;
4307 max_pixel_depth = 32;
4310 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB ||
4311 png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
4313 if (max_pixel_depth <= 32)
4314 max_pixel_depth = 32;
4317 max_pixel_depth = 64;
4322 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
4323 if (png_ptr->transformations & PNG_GRAY_TO_RGB)
4326 #ifdef PNG_READ_EXPAND_SUPPORTED
4327 (png_ptr->num_trans && (png_ptr->transformations & PNG_EXPAND)) ||
4329 #ifdef PNG_READ_FILLER_SUPPORTED
4330 (png_ptr->transformations & (PNG_FILLER)) ||
4332 png_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
4334 if (max_pixel_depth <= 16)
4335 max_pixel_depth = 32;
4338 max_pixel_depth = 64;
4343 if (max_pixel_depth <= 8)
4345 if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
4346 max_pixel_depth = 32;
4349 max_pixel_depth = 24;
4352 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
4353 max_pixel_depth = 64;
4356 max_pixel_depth = 48;
4361 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) && \
4362 defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
4363 if (png_ptr->transformations & PNG_USER_TRANSFORM)
4365 int user_pixel_depth = png_ptr->user_transform_depth *
4366 png_ptr->user_transform_channels;
4368 if (user_pixel_depth > max_pixel_depth)
4369 max_pixel_depth = user_pixel_depth;
4373 /* This value is stored in png_struct and double checked in the row read
4376 png_ptr->maximum_pixel_depth = (png_byte)max_pixel_depth;
4377 png_ptr->transformed_pixel_depth = 0; /* calculated on demand */
4379 /* Align the width on the next larger 8 pixels. Mainly used
4382 row_bytes = ((png_ptr->width + 7) & ~((png_uint_32)7));
4383 /* Calculate the maximum bytes needed, adding a byte and a pixel
4386 row_bytes = PNG_ROWBYTES(max_pixel_depth, row_bytes) +
4387 1 + ((max_pixel_depth + 7) >> 3);
4389 #ifdef PNG_MAX_MALLOC_64K
4390 if (row_bytes > (png_uint_32)65536L)
4391 png_error(png_ptr, "This image requires a row greater than 64KB");
4394 if (row_bytes + 48 > png_ptr->old_big_row_buf_size)
4396 png_free(png_ptr, png_ptr->big_row_buf);
4397 png_free(png_ptr, png_ptr->big_prev_row);
4399 if (png_ptr->interlaced)
4400 png_ptr->big_row_buf = (png_bytep)png_calloc(png_ptr,
4404 png_ptr->big_row_buf = (png_bytep)png_malloc(png_ptr, row_bytes + 48);
4406 png_ptr->big_prev_row = (png_bytep)png_malloc(png_ptr, row_bytes + 48);
4408 #ifdef PNG_ALIGNED_MEMORY_SUPPORTED
4409 /* Use 16-byte aligned memory for row_buf with at least 16 bytes
4410 * of padding before and after row_buf; treat prev_row similarly.
4411 * NOTE: the alignment is to the start of the pixels, one beyond the start
4412 * of the buffer, because of the filter byte. Prior to libpng 1.5.6 this
4413 * was incorrect; the filter byte was aligned, which had the exact
4414 * opposite effect of that intended.
4417 png_bytep temp = png_ptr->big_row_buf + 32;
4418 int extra = (int)((temp - (png_bytep)0) & 0x0f);
4419 png_ptr->row_buf = temp - extra - 1/*filter byte*/;
4421 temp = png_ptr->big_prev_row + 32;
4422 extra = (int)((temp - (png_bytep)0) & 0x0f);
4423 png_ptr->prev_row = temp - extra - 1/*filter byte*/;
4427 /* Use 31 bytes of padding before and 17 bytes after row_buf. */
4428 png_ptr->row_buf = png_ptr->big_row_buf + 31;
4429 png_ptr->prev_row = png_ptr->big_prev_row + 31;
4431 png_ptr->old_big_row_buf_size = row_bytes + 48;
4434 #ifdef PNG_MAX_MALLOC_64K
4435 if (png_ptr->rowbytes > 65535)
4436 png_error(png_ptr, "This image requires a row greater than 64KB");
4439 if (png_ptr->rowbytes > (PNG_SIZE_MAX - 1))
4440 png_error(png_ptr, "Row has too many bytes to allocate in memory");
4442 memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
4444 png_debug1(3, "width = %u,", png_ptr->width);
4445 png_debug1(3, "height = %u,", png_ptr->height);
4446 png_debug1(3, "iwidth = %u,", png_ptr->iwidth);
4447 png_debug1(3, "num_rows = %u,", png_ptr->num_rows);
4448 png_debug1(3, "rowbytes = %lu,", (unsigned long)png_ptr->rowbytes);
4449 png_debug1(3, "irowbytes = %lu",
4450 (unsigned long)PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->iwidth) + 1);
4452 /* The sequential reader needs a buffer for IDAT, but the progressive reader
4453 * does not, so free the read buffer now regardless; the sequential reader
4454 * reallocates it on demand.
4456 if (png_ptr->read_buffer)
4458 png_bytep buffer = png_ptr->read_buffer;
4460 png_ptr->read_buffer_size = 0;
4461 png_ptr->read_buffer = NULL;
4462 png_free(png_ptr, buffer);
4465 /* Finally claim the zstream for the inflate of the IDAT data, use the bits
4466 * value from the stream (note that this will result in a fatal error if the
4467 * IDAT stream has a bogus deflate header window_bits value, but this should
4468 * not be happening any longer!)
4470 if (png_inflate_claim(png_ptr, png_IDAT) != Z_OK)
4471 png_error(png_ptr, png_ptr->zstream.msg);
4473 png_ptr->flags |= PNG_FLAG_ROW_INIT;
4475 #endif /* PNG_READ_SUPPORTED */