2 /* pngrutil.c - utilities to read a PNG file
4 * Last changed in libpng 1.6.11 [June 5, 2014]
5 * Copyright (c) 1998-2014 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");
230 png_chunk_error(png_ptr, "CRC error");
238 /* Compare the CRC stored in the PNG file with that calculated by libpng from
239 * the data it has read thus far.
242 png_crc_error(png_structrp png_ptr)
244 png_byte crc_bytes[4];
248 if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name))
250 if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
251 (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
257 if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE)
261 #ifdef PNG_IO_STATE_SUPPORTED
262 png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_CRC;
265 /* The chunk CRC must be serialized in a single I/O call. */
266 png_read_data(png_ptr, crc_bytes, 4);
270 crc = png_get_uint_32(crc_bytes);
271 return ((int)(crc != png_ptr->crc));
278 #if defined(PNG_READ_iCCP_SUPPORTED) || defined(PNG_READ_iTXt_SUPPORTED) ||\
279 defined(PNG_READ_pCAL_SUPPORTED) || defined(PNG_READ_sCAL_SUPPORTED) ||\
280 defined(PNG_READ_sPLT_SUPPORTED) || defined(PNG_READ_tEXt_SUPPORTED) ||\
281 defined(PNG_READ_zTXt_SUPPORTED) || defined(PNG_SEQUENTIAL_READ_SUPPORTED)
282 /* Manage the read buffer; this simply reallocates the buffer if it is not small
283 * enough (or if it is not allocated). The routine returns a pointer to the
284 * buffer; if an error occurs and 'warn' is set the routine returns NULL, else
285 * it will call png_error (via png_malloc) on failure. (warn == 2 means
289 png_read_buffer(png_structrp png_ptr, png_alloc_size_t new_size, int warn)
291 png_bytep buffer = png_ptr->read_buffer;
293 if (buffer != NULL && new_size > png_ptr->read_buffer_size)
295 png_ptr->read_buffer = NULL;
296 png_ptr->read_buffer = NULL;
297 png_ptr->read_buffer_size = 0;
298 png_free(png_ptr, buffer);
304 buffer = png_voidcast(png_bytep, png_malloc_base(png_ptr, new_size));
308 png_ptr->read_buffer = buffer;
309 png_ptr->read_buffer_size = new_size;
312 else if (warn < 2) /* else silent */
315 png_chunk_warning(png_ptr, "insufficient memory to read chunk");
318 png_chunk_error(png_ptr, "insufficient memory to read chunk");
324 #endif /* PNG_READ_iCCP|iTXt|pCAL|sCAL|sPLT|tEXt|zTXt|SEQUENTIAL_READ */
326 /* png_inflate_claim: claim the zstream for some nefarious purpose that involves
327 * decompression. Returns Z_OK on success, else a zlib error code. It checks
328 * the owner but, in final release builds, just issues a warning if some other
329 * chunk apparently owns the stream. Prior to release it does a png_error.
332 png_inflate_claim(png_structrp png_ptr, png_uint_32 owner)
334 if (png_ptr->zowner != 0)
338 PNG_STRING_FROM_CHUNK(msg, png_ptr->zowner);
339 /* So the message that results is "<chunk> using zstream"; this is an
340 * internal error, but is very useful for debugging. i18n requirements
343 (void)png_safecat(msg, (sizeof msg), 4, " using zstream");
344 # if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
345 png_chunk_warning(png_ptr, msg);
348 png_chunk_error(png_ptr, msg);
352 /* Implementation note: unlike 'png_deflate_claim' this internal function
353 * does not take the size of the data as an argument. Some efficiency could
354 * be gained by using this when it is known *if* the zlib stream itself does
355 * not record the number; however, this is an illusion: the original writer
356 * of the PNG may have selected a lower window size, and we really must
357 * follow that because, for systems with with limited capabilities, we
358 * would otherwise reject the application's attempts to use a smaller window
359 * size (zlib doesn't have an interface to say "this or lower"!).
361 * inflateReset2 was added to zlib 1.2.4; before this the window could not be
362 * reset, therefore it is necessary to always allocate the maximum window
363 * size with earlier zlibs just in case later compressed chunks need it.
366 int ret; /* zlib return code */
367 # if PNG_ZLIB_VERNUM >= 0x1240
369 # if defined(PNG_SET_OPTION_SUPPORTED) && \
370 defined(PNG_MAXIMUM_INFLATE_WINDOW)
373 if (((png_ptr->options >> PNG_MAXIMUM_INFLATE_WINDOW) & 3) ==
380 # define window_bits 0
384 /* Set this for safety, just in case the previous owner left pointers to
385 * memory allocations.
387 png_ptr->zstream.next_in = NULL;
388 png_ptr->zstream.avail_in = 0;
389 png_ptr->zstream.next_out = NULL;
390 png_ptr->zstream.avail_out = 0;
392 if (png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED)
394 # if PNG_ZLIB_VERNUM < 0x1240
395 ret = inflateReset(&png_ptr->zstream);
397 ret = inflateReset2(&png_ptr->zstream, window_bits);
403 # if PNG_ZLIB_VERNUM < 0x1240
404 ret = inflateInit(&png_ptr->zstream);
406 ret = inflateInit2(&png_ptr->zstream, window_bits);
410 png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED;
414 png_ptr->zowner = owner;
417 png_zstream_error(png_ptr, ret);
427 #ifdef PNG_READ_COMPRESSED_TEXT_SUPPORTED
428 /* png_inflate now returns zlib error codes including Z_OK and Z_STREAM_END to
429 * allow the caller to do multiple calls if required. If the 'finish' flag is
430 * set Z_FINISH will be passed to the final inflate() call and Z_STREAM_END must
431 * be returned or there has been a problem, otherwise Z_SYNC_FLUSH is used and
432 * Z_OK or Z_STREAM_END will be returned on success.
434 * The input and output sizes are updated to the actual amounts of data consumed
435 * or written, not the amount available (as in a z_stream). The data pointers
436 * are not changed, so the next input is (data+input_size) and the next
437 * available output is (output+output_size).
440 png_inflate(png_structrp png_ptr, png_uint_32 owner, int finish,
441 /* INPUT: */ png_const_bytep input, png_uint_32p input_size_ptr,
442 /* OUTPUT: */ png_bytep output, png_alloc_size_t *output_size_ptr)
444 if (png_ptr->zowner == owner) /* Else not claimed */
447 png_alloc_size_t avail_out = *output_size_ptr;
448 png_uint_32 avail_in = *input_size_ptr;
450 /* zlib can't necessarily handle more than 65535 bytes at once (i.e. it
451 * can't even necessarily handle 65536 bytes) because the type uInt is
452 * "16 bits or more". Consequently it is necessary to chunk the input to
453 * zlib. This code uses ZLIB_IO_MAX, from pngpriv.h, as the maximum (the
454 * maximum value that can be stored in a uInt.) It is possible to set
455 * ZLIB_IO_MAX to a lower value in pngpriv.h and this may sometimes have
456 * a performance advantage, because it reduces the amount of data accessed
457 * at each step and that may give the OS more time to page it in.
459 png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input);
460 /* avail_in and avail_out are set below from 'size' */
461 png_ptr->zstream.avail_in = 0;
462 png_ptr->zstream.avail_out = 0;
464 /* Read directly into the output if it is available (this is set to
465 * a local buffer below if output is NULL).
468 png_ptr->zstream.next_out = output;
473 Byte local_buffer[PNG_INFLATE_BUF_SIZE];
475 /* zlib INPUT BUFFER */
476 /* The setting of 'avail_in' used to be outside the loop; by setting it
477 * inside it is possible to chunk the input to zlib and simply rely on
478 * zlib to advance the 'next_in' pointer. This allows arbitrary
479 * amounts of data to be passed through zlib at the unavoidable cost of
480 * requiring a window save (memcpy of up to 32768 output bytes)
481 * every ZLIB_IO_MAX input bytes.
483 avail_in += png_ptr->zstream.avail_in; /* not consumed last time */
487 if (avail_in < avail)
488 avail = (uInt)avail_in; /* safe: < than ZLIB_IO_MAX */
491 png_ptr->zstream.avail_in = avail;
493 /* zlib OUTPUT BUFFER */
494 avail_out += png_ptr->zstream.avail_out; /* not written last time */
496 avail = ZLIB_IO_MAX; /* maximum zlib can process */
500 /* Reset the output buffer each time round if output is NULL and
501 * make available the full buffer, up to 'remaining_space'
503 png_ptr->zstream.next_out = local_buffer;
504 if ((sizeof local_buffer) < avail)
505 avail = (sizeof local_buffer);
508 if (avail_out < avail)
509 avail = (uInt)avail_out; /* safe: < ZLIB_IO_MAX */
511 png_ptr->zstream.avail_out = avail;
514 /* zlib inflate call */
515 /* In fact 'avail_out' may be 0 at this point, that happens at the end
516 * of the read when the final LZ end code was not passed at the end of
517 * the previous chunk of input data. Tell zlib if we have reached the
518 * end of the output buffer.
520 ret = inflate(&png_ptr->zstream, avail_out > 0 ? Z_NO_FLUSH :
521 (finish ? Z_FINISH : Z_SYNC_FLUSH));
522 } while (ret == Z_OK);
524 /* For safety kill the local buffer pointer now */
526 png_ptr->zstream.next_out = NULL;
528 /* Claw back the 'size' and 'remaining_space' byte counts. */
529 avail_in += png_ptr->zstream.avail_in;
530 avail_out += png_ptr->zstream.avail_out;
532 /* Update the input and output sizes; the updated values are the amount
533 * consumed or written, effectively the inverse of what zlib uses.
536 *output_size_ptr -= avail_out;
539 *input_size_ptr -= avail_in;
541 /* Ensure png_ptr->zstream.msg is set (even in the success case!) */
542 png_zstream_error(png_ptr, ret);
548 /* This is a bad internal error. The recovery assigns to the zstream msg
549 * pointer, which is not owned by the caller, but this is safe; it's only
552 png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed");
553 return Z_STREAM_ERROR;
558 * Decompress trailing data in a chunk. The assumption is that read_buffer
559 * points at an allocated area holding the contents of a chunk with a
560 * trailing compressed part. What we get back is an allocated area
561 * holding the original prefix part and an uncompressed version of the
562 * trailing part (the malloc area passed in is freed).
565 png_decompress_chunk(png_structrp png_ptr,
566 png_uint_32 chunklength, png_uint_32 prefix_size,
567 png_alloc_size_t *newlength /* must be initialized to the maximum! */,
568 int terminate /*add a '\0' to the end of the uncompressed data*/)
570 /* TODO: implement different limits for different types of chunk.
572 * The caller supplies *newlength set to the maximum length of the
573 * uncompressed data, but this routine allocates space for the prefix and
574 * maybe a '\0' terminator too. We have to assume that 'prefix_size' is
575 * limited only by the maximum chunk size.
577 png_alloc_size_t limit = PNG_SIZE_MAX;
579 # ifdef PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED
580 if (png_ptr->user_chunk_malloc_max > 0 &&
581 png_ptr->user_chunk_malloc_max < limit)
582 limit = png_ptr->user_chunk_malloc_max;
583 # elif PNG_USER_CHUNK_MALLOC_MAX > 0
584 if (PNG_USER_CHUNK_MALLOC_MAX < limit)
585 limit = PNG_USER_CHUNK_MALLOC_MAX;
588 if (limit >= prefix_size + (terminate != 0))
592 limit -= prefix_size + (terminate != 0);
594 if (limit < *newlength)
597 /* Now try to claim the stream. */
598 ret = png_inflate_claim(png_ptr, png_ptr->chunk_name);
602 png_uint_32 lzsize = chunklength - prefix_size;
604 ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/,
605 /* input: */ png_ptr->read_buffer + prefix_size, &lzsize,
606 /* output: */ NULL, newlength);
608 if (ret == Z_STREAM_END)
610 /* Use 'inflateReset' here, not 'inflateReset2' because this
611 * preserves the previously decided window size (otherwise it would
612 * be necessary to store the previous window size.) In practice
613 * this doesn't matter anyway, because png_inflate will call inflate
614 * with Z_FINISH in almost all cases, so the window will not be
617 if (inflateReset(&png_ptr->zstream) == Z_OK)
619 /* Because of the limit checks above we know that the new,
620 * expanded, size will fit in a size_t (let alone an
621 * png_alloc_size_t). Use png_malloc_base here to avoid an
624 png_alloc_size_t new_size = *newlength;
625 png_alloc_size_t buffer_size = prefix_size + new_size +
627 png_bytep text = png_voidcast(png_bytep, png_malloc_base(png_ptr,
632 ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/,
633 png_ptr->read_buffer + prefix_size, &lzsize,
634 text + prefix_size, newlength);
636 if (ret == Z_STREAM_END)
638 if (new_size == *newlength)
641 text[prefix_size + *newlength] = 0;
644 memcpy(text, png_ptr->read_buffer, prefix_size);
647 png_bytep old_ptr = png_ptr->read_buffer;
649 png_ptr->read_buffer = text;
650 png_ptr->read_buffer_size = buffer_size;
651 text = old_ptr; /* freed below */
657 /* The size changed on the second read, there can be no
658 * guarantee that anything is correct at this point.
659 * The 'msg' pointer has been set to "unexpected end of
660 * LZ stream", which is fine, but return an error code
661 * that the caller won't accept.
663 ret = PNG_UNEXPECTED_ZLIB_RETURN;
667 else if (ret == Z_OK)
668 ret = PNG_UNEXPECTED_ZLIB_RETURN; /* for safety */
670 /* Free the text pointer (this is the old read_buffer on
673 png_free(png_ptr, text);
675 /* This really is very benign, but it's still an error because
676 * the extra space may otherwise be used as a Trojan Horse.
678 if (ret == Z_STREAM_END &&
679 chunklength - prefix_size != lzsize)
680 png_chunk_benign_error(png_ptr, "extra compressed data");
685 /* Out of memory allocating the buffer */
687 png_zstream_error(png_ptr, Z_MEM_ERROR);
693 /* inflateReset failed, store the error message */
694 png_zstream_error(png_ptr, ret);
696 if (ret == Z_STREAM_END)
697 ret = PNG_UNEXPECTED_ZLIB_RETURN;
701 else if (ret == Z_OK)
702 ret = PNG_UNEXPECTED_ZLIB_RETURN;
704 /* Release the claimed stream */
708 else /* the claim failed */ if (ret == Z_STREAM_END) /* impossible! */
709 ret = PNG_UNEXPECTED_ZLIB_RETURN;
716 /* Application/configuration limits exceeded */
717 png_zstream_error(png_ptr, Z_MEM_ERROR);
721 #endif /* PNG_READ_COMPRESSED_TEXT_SUPPORTED */
723 #ifdef PNG_READ_iCCP_SUPPORTED
724 /* Perform a partial read and decompress, producing 'avail_out' bytes and
725 * reading from the current chunk as required.
728 png_inflate_read(png_structrp png_ptr, png_bytep read_buffer, uInt read_size,
729 png_uint_32p chunk_bytes, png_bytep next_out, png_alloc_size_t *out_size,
732 if (png_ptr->zowner == png_ptr->chunk_name)
736 /* next_in and avail_in must have been initialized by the caller. */
737 png_ptr->zstream.next_out = next_out;
738 png_ptr->zstream.avail_out = 0; /* set in the loop */
742 if (png_ptr->zstream.avail_in == 0)
744 if (read_size > *chunk_bytes)
745 read_size = (uInt)*chunk_bytes;
746 *chunk_bytes -= read_size;
749 png_crc_read(png_ptr, read_buffer, read_size);
751 png_ptr->zstream.next_in = read_buffer;
752 png_ptr->zstream.avail_in = read_size;
755 if (png_ptr->zstream.avail_out == 0)
757 uInt avail = ZLIB_IO_MAX;
758 if (avail > *out_size)
759 avail = (uInt)*out_size;
762 png_ptr->zstream.avail_out = avail;
765 /* Use Z_SYNC_FLUSH when there is no more chunk data to ensure that all
766 * the available output is produced; this allows reading of truncated
769 ret = inflate(&png_ptr->zstream,
770 *chunk_bytes > 0 ? Z_NO_FLUSH : (finish ? Z_FINISH : Z_SYNC_FLUSH));
772 while (ret == Z_OK && (*out_size > 0 || png_ptr->zstream.avail_out > 0));
774 *out_size += png_ptr->zstream.avail_out;
775 png_ptr->zstream.avail_out = 0; /* Should not be required, but is safe */
777 /* Ensure the error message pointer is always set: */
778 png_zstream_error(png_ptr, ret);
784 png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed");
785 return Z_STREAM_ERROR;
790 /* Read and check the IDHR chunk */
792 png_handle_IHDR(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
795 png_uint_32 width, height;
796 int bit_depth, color_type, compression_type, filter_type;
799 png_debug(1, "in png_handle_IHDR");
801 if (png_ptr->mode & PNG_HAVE_IHDR)
802 png_chunk_error(png_ptr, "out of place");
804 /* Check the length */
806 png_chunk_error(png_ptr, "invalid");
808 png_ptr->mode |= PNG_HAVE_IHDR;
810 png_crc_read(png_ptr, buf, 13);
811 png_crc_finish(png_ptr, 0);
813 width = png_get_uint_31(png_ptr, buf);
814 height = png_get_uint_31(png_ptr, buf + 4);
817 compression_type = buf[10];
818 filter_type = buf[11];
819 interlace_type = buf[12];
821 /* Set internal variables */
822 png_ptr->width = width;
823 png_ptr->height = height;
824 png_ptr->bit_depth = (png_byte)bit_depth;
825 png_ptr->interlaced = (png_byte)interlace_type;
826 png_ptr->color_type = (png_byte)color_type;
827 #ifdef PNG_MNG_FEATURES_SUPPORTED
828 png_ptr->filter_type = (png_byte)filter_type;
830 png_ptr->compression_type = (png_byte)compression_type;
832 /* Find number of channels */
833 switch (png_ptr->color_type)
835 default: /* invalid, png_set_IHDR calls png_error */
836 case PNG_COLOR_TYPE_GRAY:
837 case PNG_COLOR_TYPE_PALETTE:
838 png_ptr->channels = 1;
841 case PNG_COLOR_TYPE_RGB:
842 png_ptr->channels = 3;
845 case PNG_COLOR_TYPE_GRAY_ALPHA:
846 png_ptr->channels = 2;
849 case PNG_COLOR_TYPE_RGB_ALPHA:
850 png_ptr->channels = 4;
854 /* Set up other useful info */
855 png_ptr->pixel_depth = (png_byte)(png_ptr->bit_depth *
857 png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->width);
858 png_debug1(3, "bit_depth = %d", png_ptr->bit_depth);
859 png_debug1(3, "channels = %d", png_ptr->channels);
860 png_debug1(3, "rowbytes = %lu", (unsigned long)png_ptr->rowbytes);
861 png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth,
862 color_type, interlace_type, compression_type, filter_type);
865 /* Read and check the palette */
867 png_handle_PLTE(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
869 png_color palette[PNG_MAX_PALETTE_LENGTH];
871 #ifdef PNG_POINTER_INDEXING_SUPPORTED
875 png_debug(1, "in png_handle_PLTE");
877 if (!(png_ptr->mode & PNG_HAVE_IHDR))
878 png_chunk_error(png_ptr, "missing IHDR");
880 /* Moved to before the 'after IDAT' check below because otherwise duplicate
881 * PLTE chunks are potentially ignored (the spec says there shall not be more
882 * than one PLTE, the error is not treated as benign, so this check trumps
883 * the requirement that PLTE appears before IDAT.)
885 else if (png_ptr->mode & PNG_HAVE_PLTE)
886 png_chunk_error(png_ptr, "duplicate");
888 else if (png_ptr->mode & PNG_HAVE_IDAT)
890 /* This is benign because the non-benign error happened before, when an
891 * IDAT was encountered in a color-mapped image with no PLTE.
893 png_crc_finish(png_ptr, length);
894 png_chunk_benign_error(png_ptr, "out of place");
898 png_ptr->mode |= PNG_HAVE_PLTE;
900 if (!(png_ptr->color_type & PNG_COLOR_MASK_COLOR))
902 png_crc_finish(png_ptr, length);
903 png_chunk_benign_error(png_ptr, "ignored in grayscale PNG");
907 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
908 if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
910 png_crc_finish(png_ptr, length);
915 if (length > 3*PNG_MAX_PALETTE_LENGTH || length % 3)
917 png_crc_finish(png_ptr, length);
919 if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
920 png_chunk_benign_error(png_ptr, "invalid");
923 png_chunk_error(png_ptr, "invalid");
928 /* The cast is safe because 'length' is less than 3*PNG_MAX_PALETTE_LENGTH */
929 num = (int)length / 3;
931 #ifdef PNG_POINTER_INDEXING_SUPPORTED
932 for (i = 0, pal_ptr = palette; i < num; i++, pal_ptr++)
936 png_crc_read(png_ptr, buf, 3);
937 pal_ptr->red = buf[0];
938 pal_ptr->green = buf[1];
939 pal_ptr->blue = buf[2];
942 for (i = 0; i < num; i++)
946 png_crc_read(png_ptr, buf, 3);
947 /* Don't depend upon png_color being any order */
948 palette[i].red = buf[0];
949 palette[i].green = buf[1];
950 palette[i].blue = buf[2];
954 /* If we actually need the PLTE chunk (ie for a paletted image), we do
955 * whatever the normal CRC configuration tells us. However, if we
956 * have an RGB image, the PLTE can be considered ancillary, so
957 * we will act as though it is.
959 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
960 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
963 png_crc_finish(png_ptr, 0);
966 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
967 else if (png_crc_error(png_ptr)) /* Only if we have a CRC error */
969 /* If we don't want to use the data from an ancillary chunk,
970 * we have two options: an error abort, or a warning and we
971 * ignore the data in this chunk (which should be OK, since
972 * it's considered ancillary for a RGB or RGBA image).
974 * IMPLEMENTATION NOTE: this is only here because png_crc_finish uses the
975 * chunk type to determine whether to check the ancillary or the critical
978 if (!(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_USE))
980 if (png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN)
984 png_chunk_error(png_ptr, "CRC error");
987 /* Otherwise, we (optionally) emit a warning and use the chunk. */
988 else if (!(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN))
989 png_chunk_warning(png_ptr, "CRC error");
993 /* TODO: png_set_PLTE has the side effect of setting png_ptr->palette to its
994 * own copy of the palette. This has the side effect that when png_start_row
995 * is called (this happens after any call to png_read_update_info) the
996 * info_ptr palette gets changed. This is extremely unexpected and
999 * Fix this by not sharing the palette in this way.
1001 png_set_PLTE(png_ptr, info_ptr, palette, num);
1003 /* The three chunks, bKGD, hIST and tRNS *must* appear after PLTE and before
1004 * IDAT. Prior to 1.6.0 this was not checked; instead the code merely
1005 * checked the apparent validity of a tRNS chunk inserted before PLTE on a
1006 * palette PNG. 1.6.0 attempts to rigorously follow the standard and
1007 * therefore does a benign error if the erroneous condition is detected *and*
1008 * cancels the tRNS if the benign error returns. The alternative is to
1009 * amend the standard since it would be rather hypocritical of the standards
1010 * maintainers to ignore it.
1012 #ifdef PNG_READ_tRNS_SUPPORTED
1013 if (png_ptr->num_trans > 0 ||
1014 (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0))
1016 /* Cancel this because otherwise it would be used if the transforms
1017 * require it. Don't cancel the 'valid' flag because this would prevent
1018 * detection of duplicate chunks.
1020 png_ptr->num_trans = 0;
1022 if (info_ptr != NULL)
1023 info_ptr->num_trans = 0;
1025 png_chunk_benign_error(png_ptr, "tRNS must be after");
1029 #ifdef PNG_READ_hIST_SUPPORTED
1030 if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0)
1031 png_chunk_benign_error(png_ptr, "hIST must be after");
1034 #ifdef PNG_READ_bKGD_SUPPORTED
1035 if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0)
1036 png_chunk_benign_error(png_ptr, "bKGD must be after");
1041 png_handle_IEND(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1043 png_debug(1, "in png_handle_IEND");
1045 if (!(png_ptr->mode & PNG_HAVE_IHDR) || !(png_ptr->mode & PNG_HAVE_IDAT))
1046 png_chunk_error(png_ptr, "out of place");
1048 png_ptr->mode |= (PNG_AFTER_IDAT | PNG_HAVE_IEND);
1050 png_crc_finish(png_ptr, length);
1053 png_chunk_benign_error(png_ptr, "invalid");
1055 PNG_UNUSED(info_ptr)
1058 #ifdef PNG_READ_gAMA_SUPPORTED
1060 png_handle_gAMA(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1062 png_fixed_point igamma;
1065 png_debug(1, "in png_handle_gAMA");
1067 if (!(png_ptr->mode & PNG_HAVE_IHDR))
1068 png_chunk_error(png_ptr, "missing IHDR");
1070 else if (png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE))
1072 png_crc_finish(png_ptr, length);
1073 png_chunk_benign_error(png_ptr, "out of place");
1079 png_crc_finish(png_ptr, length);
1080 png_chunk_benign_error(png_ptr, "invalid");
1084 png_crc_read(png_ptr, buf, 4);
1086 if (png_crc_finish(png_ptr, 0))
1089 igamma = png_get_fixed_point(NULL, buf);
1091 png_colorspace_set_gamma(png_ptr, &png_ptr->colorspace, igamma);
1092 png_colorspace_sync(png_ptr, info_ptr);
1096 #ifdef PNG_READ_sBIT_SUPPORTED
1098 png_handle_sBIT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1100 unsigned int truelen, i;
1101 png_byte sample_depth;
1104 png_debug(1, "in png_handle_sBIT");
1106 if (!(png_ptr->mode & PNG_HAVE_IHDR))
1107 png_chunk_error(png_ptr, "missing IHDR");
1109 else if (png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE))
1111 png_crc_finish(png_ptr, length);
1112 png_chunk_benign_error(png_ptr, "out of place");
1116 if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT))
1118 png_crc_finish(png_ptr, length);
1119 png_chunk_benign_error(png_ptr, "duplicate");
1123 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1131 truelen = png_ptr->channels;
1132 sample_depth = png_ptr->bit_depth;
1135 if (length != truelen || length > 4)
1137 png_chunk_benign_error(png_ptr, "invalid");
1138 png_crc_finish(png_ptr, length);
1142 buf[0] = buf[1] = buf[2] = buf[3] = sample_depth;
1143 png_crc_read(png_ptr, buf, truelen);
1145 if (png_crc_finish(png_ptr, 0))
1148 for (i=0; i<truelen; ++i)
1149 if (buf[i] == 0 || buf[i] > sample_depth)
1151 png_chunk_benign_error(png_ptr, "invalid");
1155 if (png_ptr->color_type & PNG_COLOR_MASK_COLOR)
1157 png_ptr->sig_bit.red = buf[0];
1158 png_ptr->sig_bit.green = buf[1];
1159 png_ptr->sig_bit.blue = buf[2];
1160 png_ptr->sig_bit.alpha = buf[3];
1165 png_ptr->sig_bit.gray = buf[0];
1166 png_ptr->sig_bit.red = buf[0];
1167 png_ptr->sig_bit.green = buf[0];
1168 png_ptr->sig_bit.blue = buf[0];
1169 png_ptr->sig_bit.alpha = buf[1];
1172 png_set_sBIT(png_ptr, info_ptr, &(png_ptr->sig_bit));
1176 #ifdef PNG_READ_cHRM_SUPPORTED
1178 png_handle_cHRM(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1183 png_debug(1, "in png_handle_cHRM");
1185 if (!(png_ptr->mode & PNG_HAVE_IHDR))
1186 png_chunk_error(png_ptr, "missing IHDR");
1188 else if (png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE))
1190 png_crc_finish(png_ptr, length);
1191 png_chunk_benign_error(png_ptr, "out of place");
1197 png_crc_finish(png_ptr, length);
1198 png_chunk_benign_error(png_ptr, "invalid");
1202 png_crc_read(png_ptr, buf, 32);
1204 if (png_crc_finish(png_ptr, 0))
1207 xy.whitex = png_get_fixed_point(NULL, buf);
1208 xy.whitey = png_get_fixed_point(NULL, buf + 4);
1209 xy.redx = png_get_fixed_point(NULL, buf + 8);
1210 xy.redy = png_get_fixed_point(NULL, buf + 12);
1211 xy.greenx = png_get_fixed_point(NULL, buf + 16);
1212 xy.greeny = png_get_fixed_point(NULL, buf + 20);
1213 xy.bluex = png_get_fixed_point(NULL, buf + 24);
1214 xy.bluey = png_get_fixed_point(NULL, buf + 28);
1216 if (xy.whitex == PNG_FIXED_ERROR ||
1217 xy.whitey == PNG_FIXED_ERROR ||
1218 xy.redx == PNG_FIXED_ERROR ||
1219 xy.redy == PNG_FIXED_ERROR ||
1220 xy.greenx == PNG_FIXED_ERROR ||
1221 xy.greeny == PNG_FIXED_ERROR ||
1222 xy.bluex == PNG_FIXED_ERROR ||
1223 xy.bluey == PNG_FIXED_ERROR)
1225 png_chunk_benign_error(png_ptr, "invalid values");
1229 /* If a colorspace error has already been output skip this chunk */
1230 if (png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID)
1233 if (png_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM)
1235 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
1236 png_colorspace_sync(png_ptr, info_ptr);
1237 png_chunk_benign_error(png_ptr, "duplicate");
1241 png_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;
1242 (void)png_colorspace_set_chromaticities(png_ptr, &png_ptr->colorspace, &xy,
1243 1/*prefer cHRM values*/);
1244 png_colorspace_sync(png_ptr, info_ptr);
1248 #ifdef PNG_READ_sRGB_SUPPORTED
1250 png_handle_sRGB(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1254 png_debug(1, "in png_handle_sRGB");
1256 if (!(png_ptr->mode & PNG_HAVE_IHDR))
1257 png_chunk_error(png_ptr, "missing IHDR");
1259 else if (png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE))
1261 png_crc_finish(png_ptr, length);
1262 png_chunk_benign_error(png_ptr, "out of place");
1268 png_crc_finish(png_ptr, length);
1269 png_chunk_benign_error(png_ptr, "invalid");
1273 png_crc_read(png_ptr, &intent, 1);
1275 if (png_crc_finish(png_ptr, 0))
1278 /* If a colorspace error has already been output skip this chunk */
1279 if (png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID)
1282 /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
1285 if (png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT)
1287 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
1288 png_colorspace_sync(png_ptr, info_ptr);
1289 png_chunk_benign_error(png_ptr, "too many profiles");
1293 (void)png_colorspace_set_sRGB(png_ptr, &png_ptr->colorspace, intent);
1294 png_colorspace_sync(png_ptr, info_ptr);
1296 #endif /* PNG_READ_sRGB_SUPPORTED */
1298 #ifdef PNG_READ_iCCP_SUPPORTED
1300 png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1301 /* Note: this does not properly handle profiles that are > 64K under DOS */
1303 png_const_charp errmsg = NULL; /* error message output, or no error */
1304 int finished = 0; /* crc checked */
1306 png_debug(1, "in png_handle_iCCP");
1308 if (!(png_ptr->mode & PNG_HAVE_IHDR))
1309 png_chunk_error(png_ptr, "missing IHDR");
1311 else if (png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE))
1313 png_crc_finish(png_ptr, length);
1314 png_chunk_benign_error(png_ptr, "out of place");
1318 /* Consistent with all the above colorspace handling an obviously *invalid*
1319 * chunk is just ignored, so does not invalidate the color space. An
1320 * alternative is to set the 'invalid' flags at the start of this routine
1321 * and only clear them in they were not set before and all the tests pass.
1322 * The minimum 'deflate' stream is assumed to be just the 2 byte header and
1323 * 4 byte checksum. The keyword must be at least one character and there is
1324 * a terminator (0) byte and the compression method.
1328 png_crc_finish(png_ptr, length);
1329 png_chunk_benign_error(png_ptr, "too short");
1333 /* If a colorspace error has already been output skip this chunk */
1334 if (png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID)
1336 png_crc_finish(png_ptr, length);
1340 /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
1343 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) == 0)
1345 uInt read_length, keyword_length;
1348 /* Find the keyword; the keyword plus separator and compression method
1349 * bytes can be at most 81 characters long.
1351 read_length = 81; /* maximum */
1352 if (read_length > length)
1353 read_length = (uInt)length;
1355 png_crc_read(png_ptr, (png_bytep)keyword, read_length);
1356 length -= read_length;
1359 while (keyword_length < 80 && keyword_length < read_length &&
1360 keyword[keyword_length] != 0)
1363 /* TODO: make the keyword checking common */
1364 if (keyword_length >= 1 && keyword_length <= 79)
1366 /* We only understand '0' compression - deflate - so if we get a
1367 * different value we can't safely decode the chunk.
1369 if (keyword_length+1 < read_length &&
1370 keyword[keyword_length+1] == PNG_COMPRESSION_TYPE_BASE)
1372 read_length -= keyword_length+2;
1374 if (png_inflate_claim(png_ptr, png_iCCP) == Z_OK)
1376 Byte profile_header[132];
1377 Byte local_buffer[PNG_INFLATE_BUF_SIZE];
1378 png_alloc_size_t size = (sizeof profile_header);
1380 png_ptr->zstream.next_in = (Bytef*)keyword + (keyword_length+2);
1381 png_ptr->zstream.avail_in = read_length;
1382 (void)png_inflate_read(png_ptr, local_buffer,
1383 (sizeof local_buffer), &length, profile_header, &size,
1384 0/*finish: don't, because the output is too small*/);
1388 /* We have the ICC profile header; do the basic header checks.
1390 const png_uint_32 profile_length =
1391 png_get_uint_32(profile_header);
1393 if (png_icc_check_length(png_ptr, &png_ptr->colorspace,
1394 keyword, profile_length))
1396 /* The length is apparently ok, so we can check the 132
1399 if (png_icc_check_header(png_ptr, &png_ptr->colorspace,
1400 keyword, profile_length, profile_header,
1401 png_ptr->color_type))
1403 /* Now read the tag table; a variable size buffer is
1404 * needed at this point, allocate one for the whole
1405 * profile. The header check has already validated
1406 * that none of these stuff will overflow.
1408 const png_uint_32 tag_count = png_get_uint_32(
1409 profile_header+128);
1410 png_bytep profile = png_read_buffer(png_ptr,
1411 profile_length, 2/*silent*/);
1413 if (profile != NULL)
1415 memcpy(profile, profile_header,
1416 (sizeof profile_header));
1418 size = 12 * tag_count;
1420 (void)png_inflate_read(png_ptr, local_buffer,
1421 (sizeof local_buffer), &length,
1422 profile + (sizeof profile_header), &size, 0);
1424 /* Still expect a buffer error because we expect
1425 * there to be some tag data!
1429 if (png_icc_check_tag_table(png_ptr,
1430 &png_ptr->colorspace, keyword, profile_length,
1433 /* The profile has been validated for basic
1434 * security issues, so read the whole thing in.
1436 size = profile_length - (sizeof profile_header)
1439 (void)png_inflate_read(png_ptr, local_buffer,
1440 (sizeof local_buffer), &length,
1441 profile + (sizeof profile_header) +
1442 12 * tag_count, &size, 1/*finish*/);
1444 if (length > 0 && !(png_ptr->flags &
1445 PNG_FLAG_BENIGN_ERRORS_WARN))
1446 errmsg = "extra compressed data";
1448 /* But otherwise allow extra data: */
1453 /* This can be handled completely, so
1456 png_chunk_warning(png_ptr,
1457 "extra compressed data");
1460 png_crc_finish(png_ptr, length);
1463 # ifdef PNG_sRGB_SUPPORTED
1464 /* Check for a match against sRGB */
1465 png_icc_set_sRGB(png_ptr,
1466 &png_ptr->colorspace, profile,
1467 png_ptr->zstream.adler);
1470 /* Steal the profile for info_ptr. */
1471 if (info_ptr != NULL)
1473 png_free_data(png_ptr, info_ptr,
1476 info_ptr->iccp_name = png_voidcast(char*,
1477 png_malloc_base(png_ptr,
1479 if (info_ptr->iccp_name != NULL)
1481 memcpy(info_ptr->iccp_name, keyword,
1483 info_ptr->iccp_proflen =
1485 info_ptr->iccp_profile = profile;
1486 png_ptr->read_buffer = NULL; /*steal*/
1487 info_ptr->free_me |= PNG_FREE_ICCP;
1488 info_ptr->valid |= PNG_INFO_iCCP;
1493 png_ptr->colorspace.flags |=
1494 PNG_COLORSPACE_INVALID;
1495 errmsg = "out of memory";
1499 /* else the profile remains in the read
1500 * buffer which gets reused for subsequent
1504 if (info_ptr != NULL)
1505 png_colorspace_sync(png_ptr, info_ptr);
1509 png_ptr->zowner = 0;
1515 errmsg = "truncated";
1518 errmsg = png_ptr->zstream.msg;
1521 /* else png_icc_check_tag_table output an error */
1524 else /* profile truncated */
1525 errmsg = png_ptr->zstream.msg;
1529 errmsg = "out of memory";
1532 /* else png_icc_check_header output an error */
1535 /* else png_icc_check_length output an error */
1538 else /* profile truncated */
1539 errmsg = png_ptr->zstream.msg;
1541 /* Release the stream */
1542 png_ptr->zowner = 0;
1545 else /* png_inflate_claim failed */
1546 errmsg = png_ptr->zstream.msg;
1550 errmsg = "bad compression method"; /* or missing */
1554 errmsg = "bad keyword";
1558 errmsg = "too many profiles";
1560 /* Failure: the reason is in 'errmsg' */
1562 png_crc_finish(png_ptr, length);
1564 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
1565 png_colorspace_sync(png_ptr, info_ptr);
1566 if (errmsg != NULL) /* else already output */
1567 png_chunk_benign_error(png_ptr, errmsg);
1569 #endif /* PNG_READ_iCCP_SUPPORTED */
1571 #ifdef PNG_READ_sPLT_SUPPORTED
1573 png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1574 /* Note: this does not properly handle chunks that are > 64K under DOS */
1576 png_bytep entry_start, buffer;
1577 png_sPLT_t new_palette;
1579 png_uint_32 data_length;
1581 png_uint_32 skip = 0;
1585 png_debug(1, "in png_handle_sPLT");
1587 #ifdef PNG_USER_LIMITS_SUPPORTED
1588 if (png_ptr->user_chunk_cache_max != 0)
1590 if (png_ptr->user_chunk_cache_max == 1)
1592 png_crc_finish(png_ptr, length);
1596 if (--png_ptr->user_chunk_cache_max == 1)
1598 png_warning(png_ptr, "No space in chunk cache for sPLT");
1599 png_crc_finish(png_ptr, length);
1605 if (!(png_ptr->mode & PNG_HAVE_IHDR))
1606 png_chunk_error(png_ptr, "missing IHDR");
1608 else if (png_ptr->mode & PNG_HAVE_IDAT)
1610 png_crc_finish(png_ptr, length);
1611 png_chunk_benign_error(png_ptr, "out of place");
1615 #ifdef PNG_MAX_MALLOC_64K
1616 if (length > 65535U)
1618 png_crc_finish(png_ptr, length);
1619 png_chunk_benign_error(png_ptr, "too large to fit in memory");
1624 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
1627 png_crc_finish(png_ptr, length);
1628 png_chunk_benign_error(png_ptr, "out of memory");
1633 /* WARNING: this may break if size_t is less than 32 bits; it is assumed
1634 * that the PNG_MAX_MALLOC_64K test is enabled in this case, but this is a
1635 * potential breakage point if the types in pngconf.h aren't exactly right.
1637 png_crc_read(png_ptr, buffer, length);
1639 if (png_crc_finish(png_ptr, skip))
1644 for (entry_start = buffer; *entry_start; entry_start++)
1645 /* Empty loop to find end of name */ ;
1649 /* A sample depth should follow the separator, and we should be on it */
1650 if (entry_start > buffer + length - 2)
1652 png_warning(png_ptr, "malformed sPLT chunk");
1656 new_palette.depth = *entry_start++;
1657 entry_size = (new_palette.depth == 8 ? 6 : 10);
1658 /* This must fit in a png_uint_32 because it is derived from the original
1659 * chunk data length.
1661 data_length = length - (png_uint_32)(entry_start - buffer);
1663 /* Integrity-check the data length */
1664 if (data_length % entry_size)
1666 png_warning(png_ptr, "sPLT chunk has bad length");
1670 dl = (png_int_32)(data_length / entry_size);
1671 max_dl = PNG_SIZE_MAX / (sizeof (png_sPLT_entry));
1675 png_warning(png_ptr, "sPLT chunk too long");
1679 new_palette.nentries = (png_int_32)(data_length / entry_size);
1681 new_palette.entries = (png_sPLT_entryp)png_malloc_warn(
1682 png_ptr, new_palette.nentries * (sizeof (png_sPLT_entry)));
1684 if (new_palette.entries == NULL)
1686 png_warning(png_ptr, "sPLT chunk requires too much memory");
1690 #ifdef PNG_POINTER_INDEXING_SUPPORTED
1691 for (i = 0; i < new_palette.nentries; i++)
1693 pp = new_palette.entries + i;
1695 if (new_palette.depth == 8)
1697 pp->red = *entry_start++;
1698 pp->green = *entry_start++;
1699 pp->blue = *entry_start++;
1700 pp->alpha = *entry_start++;
1705 pp->red = png_get_uint_16(entry_start); entry_start += 2;
1706 pp->green = png_get_uint_16(entry_start); entry_start += 2;
1707 pp->blue = png_get_uint_16(entry_start); entry_start += 2;
1708 pp->alpha = png_get_uint_16(entry_start); entry_start += 2;
1711 pp->frequency = png_get_uint_16(entry_start); entry_start += 2;
1714 pp = new_palette.entries;
1716 for (i = 0; i < new_palette.nentries; i++)
1719 if (new_palette.depth == 8)
1721 pp[i].red = *entry_start++;
1722 pp[i].green = *entry_start++;
1723 pp[i].blue = *entry_start++;
1724 pp[i].alpha = *entry_start++;
1729 pp[i].red = png_get_uint_16(entry_start); entry_start += 2;
1730 pp[i].green = png_get_uint_16(entry_start); entry_start += 2;
1731 pp[i].blue = png_get_uint_16(entry_start); entry_start += 2;
1732 pp[i].alpha = png_get_uint_16(entry_start); entry_start += 2;
1735 pp[i].frequency = png_get_uint_16(entry_start); entry_start += 2;
1739 /* Discard all chunk data except the name and stash that */
1740 new_palette.name = (png_charp)buffer;
1742 png_set_sPLT(png_ptr, info_ptr, &new_palette, 1);
1744 png_free(png_ptr, new_palette.entries);
1746 #endif /* PNG_READ_sPLT_SUPPORTED */
1748 #ifdef PNG_READ_tRNS_SUPPORTED
1750 png_handle_tRNS(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1752 png_byte readbuf[PNG_MAX_PALETTE_LENGTH];
1754 png_debug(1, "in png_handle_tRNS");
1756 if (!(png_ptr->mode & PNG_HAVE_IHDR))
1757 png_chunk_error(png_ptr, "missing IHDR");
1759 else if (png_ptr->mode & PNG_HAVE_IDAT)
1761 png_crc_finish(png_ptr, length);
1762 png_chunk_benign_error(png_ptr, "out of place");
1766 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS))
1768 png_crc_finish(png_ptr, length);
1769 png_chunk_benign_error(png_ptr, "duplicate");
1773 if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
1779 png_crc_finish(png_ptr, length);
1780 png_chunk_benign_error(png_ptr, "invalid");
1784 png_crc_read(png_ptr, buf, 2);
1785 png_ptr->num_trans = 1;
1786 png_ptr->trans_color.gray = png_get_uint_16(buf);
1789 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
1795 png_crc_finish(png_ptr, length);
1796 png_chunk_benign_error(png_ptr, "invalid");
1800 png_crc_read(png_ptr, buf, length);
1801 png_ptr->num_trans = 1;
1802 png_ptr->trans_color.red = png_get_uint_16(buf);
1803 png_ptr->trans_color.green = png_get_uint_16(buf + 2);
1804 png_ptr->trans_color.blue = png_get_uint_16(buf + 4);
1807 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1809 if (!(png_ptr->mode & PNG_HAVE_PLTE))
1811 /* TODO: is this actually an error in the ISO spec? */
1812 png_crc_finish(png_ptr, length);
1813 png_chunk_benign_error(png_ptr, "out of place");
1817 if (length > png_ptr->num_palette || length > PNG_MAX_PALETTE_LENGTH ||
1820 png_crc_finish(png_ptr, length);
1821 png_chunk_benign_error(png_ptr, "invalid");
1825 png_crc_read(png_ptr, readbuf, length);
1826 png_ptr->num_trans = (png_uint_16)length;
1831 png_crc_finish(png_ptr, length);
1832 png_chunk_benign_error(png_ptr, "invalid with alpha channel");
1836 if (png_crc_finish(png_ptr, 0))
1838 png_ptr->num_trans = 0;
1842 /* TODO: this is a horrible side effect in the palette case because the
1843 * png_struct ends up with a pointer to the tRNS buffer owned by the
1844 * png_info. Fix this.
1846 png_set_tRNS(png_ptr, info_ptr, readbuf, png_ptr->num_trans,
1847 &(png_ptr->trans_color));
1851 #ifdef PNG_READ_bKGD_SUPPORTED
1853 png_handle_bKGD(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1855 unsigned int truelen;
1857 png_color_16 background;
1859 png_debug(1, "in png_handle_bKGD");
1861 if (!(png_ptr->mode & PNG_HAVE_IHDR))
1862 png_chunk_error(png_ptr, "missing IHDR");
1864 else if ((png_ptr->mode & PNG_HAVE_IDAT) ||
1865 (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
1866 !(png_ptr->mode & PNG_HAVE_PLTE)))
1868 png_crc_finish(png_ptr, length);
1869 png_chunk_benign_error(png_ptr, "out of place");
1873 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD))
1875 png_crc_finish(png_ptr, length);
1876 png_chunk_benign_error(png_ptr, "duplicate");
1880 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1883 else if (png_ptr->color_type & PNG_COLOR_MASK_COLOR)
1889 if (length != truelen)
1891 png_crc_finish(png_ptr, length);
1892 png_chunk_benign_error(png_ptr, "invalid");
1896 png_crc_read(png_ptr, buf, truelen);
1898 if (png_crc_finish(png_ptr, 0))
1901 /* We convert the index value into RGB components so that we can allow
1902 * arbitrary RGB values for background when we have transparency, and
1903 * so it is easy to determine the RGB values of the background color
1904 * from the info_ptr struct.
1906 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1908 background.index = buf[0];
1910 if (info_ptr && info_ptr->num_palette)
1912 if (buf[0] >= info_ptr->num_palette)
1914 png_chunk_benign_error(png_ptr, "invalid index");
1918 background.red = (png_uint_16)png_ptr->palette[buf[0]].red;
1919 background.green = (png_uint_16)png_ptr->palette[buf[0]].green;
1920 background.blue = (png_uint_16)png_ptr->palette[buf[0]].blue;
1924 background.red = background.green = background.blue = 0;
1926 background.gray = 0;
1929 else if (!(png_ptr->color_type & PNG_COLOR_MASK_COLOR)) /* GRAY */
1931 background.index = 0;
1935 background.gray = png_get_uint_16(buf);
1940 background.index = 0;
1941 background.red = png_get_uint_16(buf);
1942 background.green = png_get_uint_16(buf + 2);
1943 background.blue = png_get_uint_16(buf + 4);
1944 background.gray = 0;
1947 png_set_bKGD(png_ptr, info_ptr, &background);
1951 #ifdef PNG_READ_hIST_SUPPORTED
1953 png_handle_hIST(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1955 unsigned int num, i;
1956 png_uint_16 readbuf[PNG_MAX_PALETTE_LENGTH];
1958 png_debug(1, "in png_handle_hIST");
1960 if (!(png_ptr->mode & PNG_HAVE_IHDR))
1961 png_chunk_error(png_ptr, "missing IHDR");
1963 else if ((png_ptr->mode & PNG_HAVE_IDAT) || !(png_ptr->mode & PNG_HAVE_PLTE))
1965 png_crc_finish(png_ptr, length);
1966 png_chunk_benign_error(png_ptr, "out of place");
1970 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST))
1972 png_crc_finish(png_ptr, length);
1973 png_chunk_benign_error(png_ptr, "duplicate");
1979 if (num != png_ptr->num_palette || num > PNG_MAX_PALETTE_LENGTH)
1981 png_crc_finish(png_ptr, length);
1982 png_chunk_benign_error(png_ptr, "invalid");
1986 for (i = 0; i < num; i++)
1990 png_crc_read(png_ptr, buf, 2);
1991 readbuf[i] = png_get_uint_16(buf);
1994 if (png_crc_finish(png_ptr, 0))
1997 png_set_hIST(png_ptr, info_ptr, readbuf);
2001 #ifdef PNG_READ_pHYs_SUPPORTED
2003 png_handle_pHYs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2006 png_uint_32 res_x, res_y;
2009 png_debug(1, "in png_handle_pHYs");
2011 if (!(png_ptr->mode & PNG_HAVE_IHDR))
2012 png_chunk_error(png_ptr, "missing IHDR");
2014 else if (png_ptr->mode & PNG_HAVE_IDAT)
2016 png_crc_finish(png_ptr, length);
2017 png_chunk_benign_error(png_ptr, "out of place");
2021 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
2023 png_crc_finish(png_ptr, length);
2024 png_chunk_benign_error(png_ptr, "duplicate");
2030 png_crc_finish(png_ptr, length);
2031 png_chunk_benign_error(png_ptr, "invalid");
2035 png_crc_read(png_ptr, buf, 9);
2037 if (png_crc_finish(png_ptr, 0))
2040 res_x = png_get_uint_32(buf);
2041 res_y = png_get_uint_32(buf + 4);
2043 png_set_pHYs(png_ptr, info_ptr, res_x, res_y, unit_type);
2047 #ifdef PNG_READ_oFFs_SUPPORTED
2049 png_handle_oFFs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2052 png_int_32 offset_x, offset_y;
2055 png_debug(1, "in png_handle_oFFs");
2057 if (!(png_ptr->mode & PNG_HAVE_IHDR))
2058 png_chunk_error(png_ptr, "missing IHDR");
2060 else if (png_ptr->mode & PNG_HAVE_IDAT)
2062 png_crc_finish(png_ptr, length);
2063 png_chunk_benign_error(png_ptr, "out of place");
2067 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs))
2069 png_crc_finish(png_ptr, length);
2070 png_chunk_benign_error(png_ptr, "duplicate");
2076 png_crc_finish(png_ptr, length);
2077 png_chunk_benign_error(png_ptr, "invalid");
2081 png_crc_read(png_ptr, buf, 9);
2083 if (png_crc_finish(png_ptr, 0))
2086 offset_x = png_get_int_32(buf);
2087 offset_y = png_get_int_32(buf + 4);
2089 png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y, unit_type);
2093 #ifdef PNG_READ_pCAL_SUPPORTED
2094 /* Read the pCAL chunk (described in the PNG Extensions document) */
2096 png_handle_pCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2099 png_byte type, nparams;
2100 png_bytep buffer, buf, units, endptr;
2104 png_debug(1, "in png_handle_pCAL");
2106 if (!(png_ptr->mode & PNG_HAVE_IHDR))
2107 png_chunk_error(png_ptr, "missing IHDR");
2109 else if (png_ptr->mode & PNG_HAVE_IDAT)
2111 png_crc_finish(png_ptr, length);
2112 png_chunk_benign_error(png_ptr, "out of place");
2116 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL))
2118 png_crc_finish(png_ptr, length);
2119 png_chunk_benign_error(png_ptr, "duplicate");
2123 png_debug1(2, "Allocating and reading pCAL chunk data (%u bytes)",
2126 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
2130 png_crc_finish(png_ptr, length);
2131 png_chunk_benign_error(png_ptr, "out of memory");
2135 png_crc_read(png_ptr, buffer, length);
2137 if (png_crc_finish(png_ptr, 0))
2140 buffer[length] = 0; /* Null terminate the last string */
2142 png_debug(3, "Finding end of pCAL purpose string");
2143 for (buf = buffer; *buf; buf++)
2146 endptr = buffer + length;
2148 /* We need to have at least 12 bytes after the purpose string
2149 * in order to get the parameter information.
2151 if (endptr <= buf + 12)
2153 png_chunk_benign_error(png_ptr, "invalid");
2157 png_debug(3, "Reading pCAL X0, X1, type, nparams, and units");
2158 X0 = png_get_int_32((png_bytep)buf+1);
2159 X1 = png_get_int_32((png_bytep)buf+5);
2164 png_debug(3, "Checking pCAL equation type and number of parameters");
2165 /* Check that we have the right number of parameters for known
2168 if ((type == PNG_EQUATION_LINEAR && nparams != 2) ||
2169 (type == PNG_EQUATION_BASE_E && nparams != 3) ||
2170 (type == PNG_EQUATION_ARBITRARY && nparams != 3) ||
2171 (type == PNG_EQUATION_HYPERBOLIC && nparams != 4))
2173 png_chunk_benign_error(png_ptr, "invalid parameter count");
2177 else if (type >= PNG_EQUATION_LAST)
2179 png_chunk_benign_error(png_ptr, "unrecognized equation type");
2182 for (buf = units; *buf; buf++)
2183 /* Empty loop to move past the units string. */ ;
2185 png_debug(3, "Allocating pCAL parameters array");
2187 params = png_voidcast(png_charpp, png_malloc_warn(png_ptr,
2188 nparams * (sizeof (png_charp))));
2192 png_chunk_benign_error(png_ptr, "out of memory");
2196 /* Get pointers to the start of each parameter string. */
2197 for (i = 0; i < nparams; i++)
2199 buf++; /* Skip the null string terminator from previous parameter. */
2201 png_debug1(3, "Reading pCAL parameter %d", i);
2203 for (params[i] = (png_charp)buf; buf <= endptr && *buf != 0; buf++)
2204 /* Empty loop to move past each parameter string */ ;
2206 /* Make sure we haven't run out of data yet */
2209 png_free(png_ptr, params);
2210 png_chunk_benign_error(png_ptr, "invalid data");
2215 png_set_pCAL(png_ptr, info_ptr, (png_charp)buffer, X0, X1, type, nparams,
2216 (png_charp)units, params);
2218 png_free(png_ptr, params);
2222 #ifdef PNG_READ_sCAL_SUPPORTED
2223 /* Read the sCAL chunk */
2225 png_handle_sCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2231 png_debug(1, "in png_handle_sCAL");
2233 if (!(png_ptr->mode & PNG_HAVE_IHDR))
2234 png_chunk_error(png_ptr, "missing IHDR");
2236 else if (png_ptr->mode & PNG_HAVE_IDAT)
2238 png_crc_finish(png_ptr, length);
2239 png_chunk_benign_error(png_ptr, "out of place");
2243 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sCAL))
2245 png_crc_finish(png_ptr, length);
2246 png_chunk_benign_error(png_ptr, "duplicate");
2250 /* Need unit type, width, \0, height: minimum 4 bytes */
2251 else if (length < 4)
2253 png_crc_finish(png_ptr, length);
2254 png_chunk_benign_error(png_ptr, "invalid");
2258 png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)",
2261 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
2265 png_chunk_benign_error(png_ptr, "out of memory");
2266 png_crc_finish(png_ptr, length);
2270 png_crc_read(png_ptr, buffer, length);
2271 buffer[length] = 0; /* Null terminate the last string */
2273 if (png_crc_finish(png_ptr, 0))
2276 /* Validate the unit. */
2277 if (buffer[0] != 1 && buffer[0] != 2)
2279 png_chunk_benign_error(png_ptr, "invalid unit");
2283 /* Validate the ASCII numbers, need two ASCII numbers separated by
2284 * a '\0' and they need to fit exactly in the chunk data.
2289 if (!png_check_fp_number((png_const_charp)buffer, length, &state, &i) ||
2290 i >= length || buffer[i++] != 0)
2291 png_chunk_benign_error(png_ptr, "bad width format");
2293 else if (!PNG_FP_IS_POSITIVE(state))
2294 png_chunk_benign_error(png_ptr, "non-positive width");
2298 png_size_t heighti = i;
2301 if (!png_check_fp_number((png_const_charp)buffer, length, &state, &i) ||
2303 png_chunk_benign_error(png_ptr, "bad height format");
2305 else if (!PNG_FP_IS_POSITIVE(state))
2306 png_chunk_benign_error(png_ptr, "non-positive height");
2309 /* This is the (only) success case. */
2310 png_set_sCAL_s(png_ptr, info_ptr, buffer[0],
2311 (png_charp)buffer+1, (png_charp)buffer+heighti);
2316 #ifdef PNG_READ_tIME_SUPPORTED
2318 png_handle_tIME(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2323 png_debug(1, "in png_handle_tIME");
2325 if (!(png_ptr->mode & PNG_HAVE_IHDR))
2326 png_chunk_error(png_ptr, "missing IHDR");
2328 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME))
2330 png_crc_finish(png_ptr, length);
2331 png_chunk_benign_error(png_ptr, "duplicate");
2335 if (png_ptr->mode & PNG_HAVE_IDAT)
2336 png_ptr->mode |= PNG_AFTER_IDAT;
2340 png_crc_finish(png_ptr, length);
2341 png_chunk_benign_error(png_ptr, "invalid");
2345 png_crc_read(png_ptr, buf, 7);
2347 if (png_crc_finish(png_ptr, 0))
2350 mod_time.second = buf[6];
2351 mod_time.minute = buf[5];
2352 mod_time.hour = buf[4];
2353 mod_time.day = buf[3];
2354 mod_time.month = buf[2];
2355 mod_time.year = png_get_uint_16(buf);
2357 png_set_tIME(png_ptr, info_ptr, &mod_time);
2361 #ifdef PNG_READ_tEXt_SUPPORTED
2362 /* Note: this does not properly handle chunks that are > 64K under DOS */
2364 png_handle_tEXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2370 png_uint_32 skip = 0;
2372 png_debug(1, "in png_handle_tEXt");
2374 #ifdef PNG_USER_LIMITS_SUPPORTED
2375 if (png_ptr->user_chunk_cache_max != 0)
2377 if (png_ptr->user_chunk_cache_max == 1)
2379 png_crc_finish(png_ptr, length);
2383 if (--png_ptr->user_chunk_cache_max == 1)
2385 png_crc_finish(png_ptr, length);
2386 png_chunk_benign_error(png_ptr, "no space in chunk cache");
2392 if (!(png_ptr->mode & PNG_HAVE_IHDR))
2393 png_chunk_error(png_ptr, "missing IHDR");
2395 if (png_ptr->mode & PNG_HAVE_IDAT)
2396 png_ptr->mode |= PNG_AFTER_IDAT;
2398 #ifdef PNG_MAX_MALLOC_64K
2399 if (length > 65535U)
2401 png_crc_finish(png_ptr, length);
2402 png_chunk_benign_error(png_ptr, "too large to fit in memory");
2407 buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/);
2411 png_chunk_benign_error(png_ptr, "out of memory");
2415 png_crc_read(png_ptr, buffer, length);
2417 if (png_crc_finish(png_ptr, skip))
2420 key = (png_charp)buffer;
2423 for (text = key; *text; text++)
2424 /* Empty loop to find end of key */ ;
2426 if (text != key + length)
2429 text_info.compression = PNG_TEXT_COMPRESSION_NONE;
2430 text_info.key = key;
2431 text_info.lang = NULL;
2432 text_info.lang_key = NULL;
2433 text_info.itxt_length = 0;
2434 text_info.text = text;
2435 text_info.text_length = strlen(text);
2437 if (png_set_text_2(png_ptr, info_ptr, &text_info, 1))
2438 png_warning(png_ptr, "Insufficient memory to process text chunk");
2442 #ifdef PNG_READ_zTXt_SUPPORTED
2443 /* Note: this does not correctly handle chunks that are > 64K under DOS */
2445 png_handle_zTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2447 png_const_charp errmsg = NULL;
2449 png_uint_32 keyword_length;
2451 png_debug(1, "in png_handle_zTXt");
2453 #ifdef PNG_USER_LIMITS_SUPPORTED
2454 if (png_ptr->user_chunk_cache_max != 0)
2456 if (png_ptr->user_chunk_cache_max == 1)
2458 png_crc_finish(png_ptr, length);
2462 if (--png_ptr->user_chunk_cache_max == 1)
2464 png_crc_finish(png_ptr, length);
2465 png_chunk_benign_error(png_ptr, "no space in chunk cache");
2471 if (!(png_ptr->mode & PNG_HAVE_IHDR))
2472 png_chunk_error(png_ptr, "missing IHDR");
2474 if (png_ptr->mode & PNG_HAVE_IDAT)
2475 png_ptr->mode |= PNG_AFTER_IDAT;
2477 buffer = png_read_buffer(png_ptr, length, 2/*silent*/);
2481 png_crc_finish(png_ptr, length);
2482 png_chunk_benign_error(png_ptr, "out of memory");
2486 png_crc_read(png_ptr, buffer, length);
2488 if (png_crc_finish(png_ptr, 0))
2491 /* TODO: also check that the keyword contents match the spec! */
2492 for (keyword_length = 0;
2493 keyword_length < length && buffer[keyword_length] != 0;
2495 /* Empty loop to find end of name */ ;
2497 if (keyword_length > 79 || keyword_length < 1)
2498 errmsg = "bad keyword";
2500 /* zTXt must have some LZ data after the keyword, although it may expand to
2501 * zero bytes; we need a '\0' at the end of the keyword, the compression type
2504 else if (keyword_length + 3 > length)
2505 errmsg = "truncated";
2507 else if (buffer[keyword_length+1] != PNG_COMPRESSION_TYPE_BASE)
2508 errmsg = "unknown compression type";
2512 png_alloc_size_t uncompressed_length = PNG_SIZE_MAX;
2514 /* TODO: at present png_decompress_chunk imposes a single application
2515 * level memory limit, this should be split to different values for iCCP
2518 if (png_decompress_chunk(png_ptr, length, keyword_length+2,
2519 &uncompressed_length, 1/*terminate*/) == Z_STREAM_END)
2523 /* It worked; png_ptr->read_buffer now looks like a tEXt chunk except
2524 * for the extra compression type byte and the fact that it isn't
2525 * necessarily '\0' terminated.
2527 buffer = png_ptr->read_buffer;
2528 buffer[uncompressed_length+(keyword_length+2)] = 0;
2530 text.compression = PNG_TEXT_COMPRESSION_zTXt;
2531 text.key = (png_charp)buffer;
2532 text.text = (png_charp)(buffer + keyword_length+2);
2533 text.text_length = uncompressed_length;
2534 text.itxt_length = 0;
2536 text.lang_key = NULL;
2538 if (png_set_text_2(png_ptr, info_ptr, &text, 1))
2539 errmsg = "insufficient memory";
2543 errmsg = png_ptr->zstream.msg;
2547 png_chunk_benign_error(png_ptr, errmsg);
2551 #ifdef PNG_READ_iTXt_SUPPORTED
2552 /* Note: this does not correctly handle chunks that are > 64K under DOS */
2554 png_handle_iTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2556 png_const_charp errmsg = NULL;
2558 png_uint_32 prefix_length;
2560 png_debug(1, "in png_handle_iTXt");
2562 #ifdef PNG_USER_LIMITS_SUPPORTED
2563 if (png_ptr->user_chunk_cache_max != 0)
2565 if (png_ptr->user_chunk_cache_max == 1)
2567 png_crc_finish(png_ptr, length);
2571 if (--png_ptr->user_chunk_cache_max == 1)
2573 png_crc_finish(png_ptr, length);
2574 png_chunk_benign_error(png_ptr, "no space in chunk cache");
2580 if (!(png_ptr->mode & PNG_HAVE_IHDR))
2581 png_chunk_error(png_ptr, "missing IHDR");
2583 if (png_ptr->mode & PNG_HAVE_IDAT)
2584 png_ptr->mode |= PNG_AFTER_IDAT;
2586 buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/);
2590 png_crc_finish(png_ptr, length);
2591 png_chunk_benign_error(png_ptr, "out of memory");
2595 png_crc_read(png_ptr, buffer, length);
2597 if (png_crc_finish(png_ptr, 0))
2600 /* First the keyword. */
2601 for (prefix_length=0;
2602 prefix_length < length && buffer[prefix_length] != 0;
2606 /* Perform a basic check on the keyword length here. */
2607 if (prefix_length > 79 || prefix_length < 1)
2608 errmsg = "bad keyword";
2610 /* Expect keyword, compression flag, compression type, language, translated
2611 * keyword (both may be empty but are 0 terminated) then the text, which may
2614 else if (prefix_length + 5 > length)
2615 errmsg = "truncated";
2617 else if (buffer[prefix_length+1] == 0 ||
2618 (buffer[prefix_length+1] == 1 &&
2619 buffer[prefix_length+2] == PNG_COMPRESSION_TYPE_BASE))
2621 int compressed = buffer[prefix_length+1] != 0;
2622 png_uint_32 language_offset, translated_keyword_offset;
2623 png_alloc_size_t uncompressed_length = 0;
2625 /* Now the language tag */
2627 language_offset = prefix_length;
2629 for (; prefix_length < length && buffer[prefix_length] != 0;
2633 /* WARNING: the length may be invalid here, this is checked below. */
2634 translated_keyword_offset = ++prefix_length;
2636 for (; prefix_length < length && buffer[prefix_length] != 0;
2640 /* prefix_length should now be at the trailing '\0' of the translated
2641 * keyword, but it may already be over the end. None of this arithmetic
2642 * can overflow because chunks are at most 2^31 bytes long, but on 16-bit
2643 * systems the available allocation may overflow.
2647 if (!compressed && prefix_length <= length)
2648 uncompressed_length = length - prefix_length;
2650 else if (compressed && prefix_length < length)
2652 uncompressed_length = PNG_SIZE_MAX;
2654 /* TODO: at present png_decompress_chunk imposes a single application
2655 * level memory limit, this should be split to different values for
2656 * iCCP and text chunks.
2658 if (png_decompress_chunk(png_ptr, length, prefix_length,
2659 &uncompressed_length, 1/*terminate*/) == Z_STREAM_END)
2660 buffer = png_ptr->read_buffer;
2663 errmsg = png_ptr->zstream.msg;
2667 errmsg = "truncated";
2673 buffer[uncompressed_length+prefix_length] = 0;
2675 if (compressed != 0)
2676 text.compression = PNG_ITXT_COMPRESSION_NONE;
2679 text.compression = PNG_ITXT_COMPRESSION_zTXt;
2681 text.key = (png_charp)buffer;
2682 text.lang = (png_charp)buffer + language_offset;
2683 text.lang_key = (png_charp)buffer + translated_keyword_offset;
2684 text.text = (png_charp)buffer + prefix_length;
2685 text.text_length = 0;
2686 text.itxt_length = uncompressed_length;
2688 if (png_set_text_2(png_ptr, info_ptr, &text, 1))
2689 errmsg = "insufficient memory";
2694 errmsg = "bad compression info";
2697 png_chunk_benign_error(png_ptr, errmsg);
2701 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
2702 /* Utility function for png_handle_unknown; set up png_ptr::unknown_chunk */
2704 png_cache_unknown_chunk(png_structrp png_ptr, png_uint_32 length)
2706 png_alloc_size_t limit = PNG_SIZE_MAX;
2708 if (png_ptr->unknown_chunk.data != NULL)
2710 png_free(png_ptr, png_ptr->unknown_chunk.data);
2711 png_ptr->unknown_chunk.data = NULL;
2714 # ifdef PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED
2715 if (png_ptr->user_chunk_malloc_max > 0 &&
2716 png_ptr->user_chunk_malloc_max < limit)
2717 limit = png_ptr->user_chunk_malloc_max;
2719 # elif PNG_USER_CHUNK_MALLOC_MAX > 0
2720 if (PNG_USER_CHUNK_MALLOC_MAX < limit)
2721 limit = PNG_USER_CHUNK_MALLOC_MAX;
2724 if (length <= limit)
2726 PNG_CSTRING_FROM_CHUNK(png_ptr->unknown_chunk.name, png_ptr->chunk_name);
2727 /* The following is safe because of the PNG_SIZE_MAX init above */
2728 png_ptr->unknown_chunk.size = (png_size_t)length/*SAFE*/;
2729 /* 'mode' is a flag array, only the bottom four bits matter here */
2730 png_ptr->unknown_chunk.location = (png_byte)png_ptr->mode/*SAFE*/;
2733 png_ptr->unknown_chunk.data = NULL;
2737 /* Do a 'warn' here - it is handled below. */
2738 png_ptr->unknown_chunk.data = png_voidcast(png_bytep,
2739 png_malloc_warn(png_ptr, length));
2743 if (png_ptr->unknown_chunk.data == NULL && length > 0)
2745 /* This is benign because we clean up correctly */
2746 png_crc_finish(png_ptr, length);
2747 png_chunk_benign_error(png_ptr, "unknown chunk exceeds memory limits");
2754 png_crc_read(png_ptr, png_ptr->unknown_chunk.data, length);
2755 png_crc_finish(png_ptr, 0);
2759 #endif /* PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */
2761 /* Handle an unknown, or known but disabled, chunk */
2763 png_handle_unknown(png_structrp png_ptr, png_inforp info_ptr,
2764 png_uint_32 length, int keep)
2766 int handled = 0; /* the chunk was handled */
2768 png_debug(1, "in png_handle_unknown");
2770 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
2771 /* NOTE: this code is based on the code in libpng-1.4.12 except for fixing
2772 * the bug which meant that setting a non-default behavior for a specific
2773 * chunk would be ignored (the default was always used unless a user
2774 * callback was installed).
2776 * 'keep' is the value from the png_chunk_unknown_handling, the setting for
2777 * this specific chunk_name, if PNG_HANDLE_AS_UNKNOWN_SUPPORTED, if not it
2778 * will always be PNG_HANDLE_CHUNK_AS_DEFAULT and it needs to be set here.
2779 * This is just an optimization to avoid multiple calls to the lookup
2782 # ifndef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
2783 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
2784 keep = png_chunk_unknown_handling(png_ptr, png_ptr->chunk_name);
2788 /* One of the following methods will read the chunk or skip it (at least one
2789 * of these is always defined because this is the only way to switch on
2790 * PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
2792 # ifdef PNG_READ_USER_CHUNKS_SUPPORTED
2793 /* The user callback takes precedence over the chunk keep value, but the
2794 * keep value is still required to validate a save of a critical chunk.
2796 if (png_ptr->read_user_chunk_fn != NULL)
2798 if (png_cache_unknown_chunk(png_ptr, length))
2800 /* Callback to user unknown chunk handler */
2801 int ret = (*(png_ptr->read_user_chunk_fn))(png_ptr,
2802 &png_ptr->unknown_chunk);
2805 * negative: An error occured, png_chunk_error will be called.
2806 * zero: The chunk was not handled, the chunk will be discarded
2807 * unless png_set_keep_unknown_chunks has been used to set
2808 * a 'keep' behavior for this particular chunk, in which
2809 * case that will be used. A critical chunk will cause an
2810 * error at this point unless it is to be saved.
2811 * positive: The chunk was handled, libpng will ignore/discard it.
2814 png_chunk_error(png_ptr, "error in user chunk");
2818 /* If the keep value is 'default' or 'never' override it, but
2819 * still error out on critical chunks unless the keep value is
2820 * 'always' While this is weird it is the behavior in 1.4.12.
2821 * A possible improvement would be to obey the value set for the
2822 * chunk, but this would be an API change that would probably
2823 * damage some applications.
2825 * The png_app_warning below catches the case that matters, where
2826 * the application has not set specific save or ignore for this
2827 * chunk or global save or ignore.
2829 if (keep < PNG_HANDLE_CHUNK_IF_SAFE)
2831 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
2832 if (png_ptr->unknown_default < PNG_HANDLE_CHUNK_IF_SAFE)
2834 png_chunk_warning(png_ptr, "Saving unknown chunk:");
2835 png_app_warning(png_ptr,
2836 "forcing save of an unhandled chunk;"
2837 " please call png_set_keep_unknown_chunks");
2838 /* with keep = PNG_HANDLE_CHUNK_IF_SAFE */
2841 keep = PNG_HANDLE_CHUNK_IF_SAFE;
2845 else /* chunk was handled */
2848 /* Critical chunks can be safely discarded at this point. */
2849 keep = PNG_HANDLE_CHUNK_NEVER;
2854 keep = PNG_HANDLE_CHUNK_NEVER; /* insufficient memory */
2858 /* Use the SAVE_UNKNOWN_CHUNKS code or skip the chunk */
2859 # endif /* PNG_READ_USER_CHUNKS_SUPPORTED */
2861 # ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
2863 /* keep is currently just the per-chunk setting, if there was no
2864 * setting change it to the global default now (not that this may
2865 * still be AS_DEFAULT) then obtain the cache of the chunk if required,
2866 * if not simply skip the chunk.
2868 if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT)
2869 keep = png_ptr->unknown_default;
2871 if (keep == PNG_HANDLE_CHUNK_ALWAYS ||
2872 (keep == PNG_HANDLE_CHUNK_IF_SAFE &&
2873 PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)))
2875 if (!png_cache_unknown_chunk(png_ptr, length))
2876 keep = PNG_HANDLE_CHUNK_NEVER;
2880 png_crc_finish(png_ptr, length);
2883 # ifndef PNG_READ_USER_CHUNKS_SUPPORTED
2884 # error no method to support READ_UNKNOWN_CHUNKS
2888 /* If here there is no read callback pointer set and no support is
2889 * compiled in to just save the unknown chunks, so simply skip this
2890 * chunk. If 'keep' is something other than AS_DEFAULT or NEVER then
2891 * the app has erroneously asked for unknown chunk saving when there
2894 if (keep > PNG_HANDLE_CHUNK_NEVER)
2895 png_app_error(png_ptr, "no unknown chunk support available");
2897 png_crc_finish(png_ptr, length);
2901 # ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
2902 /* Now store the chunk in the chunk list if appropriate, and if the limits
2905 if (keep == PNG_HANDLE_CHUNK_ALWAYS ||
2906 (keep == PNG_HANDLE_CHUNK_IF_SAFE &&
2907 PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)))
2909 # ifdef PNG_USER_LIMITS_SUPPORTED
2910 switch (png_ptr->user_chunk_cache_max)
2913 png_ptr->user_chunk_cache_max = 1;
2914 png_chunk_benign_error(png_ptr, "no space in chunk cache");
2917 /* NOTE: prior to 1.6.0 this case resulted in an unknown critical
2918 * chunk being skipped, now there will be a hard error below.
2922 default: /* not at limit */
2923 --(png_ptr->user_chunk_cache_max);
2925 case 0: /* no limit */
2926 # endif /* PNG_USER_LIMITS_SUPPORTED */
2927 /* Here when the limit isn't reached or when limits are compiled
2928 * out; store the chunk.
2930 png_set_unknown_chunks(png_ptr, info_ptr,
2931 &png_ptr->unknown_chunk, 1);
2933 # ifdef PNG_USER_LIMITS_SUPPORTED
2938 # else /* no store support: the chunk must be handled by the user callback */
2939 PNG_UNUSED(info_ptr)
2942 /* Regardless of the error handling below the cached data (if any) can be
2943 * freed now. Notice that the data is not freed if there is a png_error, but
2944 * it will be freed by destroy_read_struct.
2946 if (png_ptr->unknown_chunk.data != NULL)
2947 png_free(png_ptr, png_ptr->unknown_chunk.data);
2948 png_ptr->unknown_chunk.data = NULL;
2950 #else /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */
2951 /* There is no support to read an unknown chunk, so just skip it. */
2952 png_crc_finish(png_ptr, length);
2953 PNG_UNUSED(info_ptr)
2955 #endif /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */
2957 /* Check for unhandled critical chunks */
2958 if (!handled && PNG_CHUNK_CRITICAL(png_ptr->chunk_name))
2959 png_chunk_error(png_ptr, "unhandled critical chunk");
2962 /* This function is called to verify that a chunk name is valid.
2963 * This function can't have the "critical chunk check" incorporated
2964 * into it, since in the future we will need to be able to call user
2965 * functions to handle unknown critical chunks after we check that
2966 * the chunk name itself is valid.
2969 /* Bit hacking: the test for an invalid byte in the 4 byte chunk name is:
2971 * ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
2975 png_check_chunk_name(png_structrp png_ptr, png_uint_32 chunk_name)
2979 png_debug(1, "in png_check_chunk_name");
2981 for (i=1; i<=4; ++i)
2983 int c = chunk_name & 0xff;
2985 if (c < 65 || c > 122 || (c > 90 && c < 97))
2986 png_chunk_error(png_ptr, "invalid chunk type");
2992 /* Combines the row recently read in with the existing pixels in the row. This
2993 * routine takes care of alpha and transparency if requested. This routine also
2994 * handles the two methods of progressive display of interlaced images,
2995 * depending on the 'display' value; if 'display' is true then the whole row
2996 * (dp) is filled from the start by replicating the available pixels. If
2997 * 'display' is false only those pixels present in the pass are filled in.
3000 png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display)
3002 unsigned int pixel_depth = png_ptr->transformed_pixel_depth;
3003 png_const_bytep sp = png_ptr->row_buf + 1;
3004 png_uint_32 row_width = png_ptr->width;
3005 unsigned int pass = png_ptr->pass;
3006 png_bytep end_ptr = 0;
3007 png_byte end_byte = 0;
3008 unsigned int end_mask;
3010 png_debug(1, "in png_combine_row");
3012 /* Added in 1.5.6: it should not be possible to enter this routine until at
3013 * least one row has been read from the PNG data and transformed.
3015 if (pixel_depth == 0)
3016 png_error(png_ptr, "internal row logic error");
3018 /* Added in 1.5.4: the pixel depth should match the information returned by
3019 * any call to png_read_update_info at this point. Do not continue if we got
3022 if (png_ptr->info_rowbytes != 0 && png_ptr->info_rowbytes !=
3023 PNG_ROWBYTES(pixel_depth, row_width))
3024 png_error(png_ptr, "internal row size calculation error");
3026 /* Don't expect this to ever happen: */
3028 png_error(png_ptr, "internal row width error");
3030 /* Preserve the last byte in cases where only part of it will be overwritten,
3031 * the multiply below may overflow, we don't care because ANSI-C guarantees
3032 * we get the low bits.
3034 end_mask = (pixel_depth * row_width) & 7;
3037 /* end_ptr == NULL is a flag to say do nothing */
3038 end_ptr = dp + PNG_ROWBYTES(pixel_depth, row_width) - 1;
3039 end_byte = *end_ptr;
3040 # ifdef PNG_READ_PACKSWAP_SUPPORTED
3041 if (png_ptr->transformations & PNG_PACKSWAP) /* little-endian byte */
3042 end_mask = 0xff << end_mask;
3044 else /* big-endian byte */
3046 end_mask = 0xff >> end_mask;
3047 /* end_mask is now the bits to *keep* from the destination row */
3050 /* For non-interlaced images this reduces to a memcpy(). A memcpy()
3051 * will also happen if interlacing isn't supported or if the application
3052 * does not call png_set_interlace_handling(). In the latter cases the
3053 * caller just gets a sequence of the unexpanded rows from each interlace
3056 #ifdef PNG_READ_INTERLACING_SUPPORTED
3057 if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE) &&
3058 pass < 6 && (display == 0 ||
3059 /* The following copies everything for 'display' on passes 0, 2 and 4. */
3060 (display == 1 && (pass & 1) != 0)))
3062 /* Narrow images may have no bits in a pass; the caller should handle
3063 * this, but this test is cheap:
3065 if (row_width <= PNG_PASS_START_COL(pass))
3068 if (pixel_depth < 8)
3070 /* For pixel depths up to 4 bpp the 8-pixel mask can be expanded to fit
3071 * into 32 bits, then a single loop over the bytes using the four byte
3072 * values in the 32-bit mask can be used. For the 'display' option the
3073 * expanded mask may also not require any masking within a byte. To
3074 * make this work the PACKSWAP option must be taken into account - it
3075 * simply requires the pixels to be reversed in each byte.
3077 * The 'regular' case requires a mask for each of the first 6 passes,
3078 * the 'display' case does a copy for the even passes in the range
3079 * 0..6. This has already been handled in the test above.
3081 * The masks are arranged as four bytes with the first byte to use in
3082 * the lowest bits (little-endian) regardless of the order (PACKSWAP or
3083 * not) of the pixels in each byte.
3085 * NOTE: the whole of this logic depends on the caller of this function
3086 * only calling it on rows appropriate to the pass. This function only
3087 * understands the 'x' logic; the 'y' logic is handled by the caller.
3089 * The following defines allow generation of compile time constant bit
3090 * masks for each pixel depth and each possibility of swapped or not
3091 * swapped bytes. Pass 'p' is in the range 0..6; 'x', a pixel index,
3092 * is in the range 0..7; and the result is 1 if the pixel is to be
3093 * copied in the pass, 0 if not. 'S' is for the sparkle method, 'B'
3094 * for the block method.
3096 * With some compilers a compile time expression of the general form:
3098 * (shift >= 32) ? (a >> (shift-32)) : (b >> shift)
3100 * Produces warnings with values of 'shift' in the range 33 to 63
3101 * because the right hand side of the ?: expression is evaluated by
3102 * the compiler even though it isn't used. Microsoft Visual C (various
3103 * versions) and the Intel C compiler are known to do this. To avoid
3104 * this the following macros are used in 1.5.6. This is a temporary
3105 * solution to avoid destabilizing the code during the release process.
3107 # if PNG_USE_COMPILE_TIME_MASKS
3108 # define PNG_LSR(x,s) ((x)>>((s) & 0x1f))
3109 # define PNG_LSL(x,s) ((x)<<((s) & 0x1f))
3111 # define PNG_LSR(x,s) ((x)>>(s))
3112 # define PNG_LSL(x,s) ((x)<<(s))
3114 # define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\
3115 PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1)
3116 # define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\
3117 PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1)
3119 /* Return a mask for pass 'p' pixel 'x' at depth 'd'. The mask is
3120 * little endian - the first pixel is at bit 0 - however the extra
3121 * parameter 's' can be set to cause the mask position to be swapped
3122 * within each byte, to match the PNG format. This is done by XOR of
3123 * the shift with 7, 6 or 4 for bit depths 1, 2 and 4.
3125 # define PIXEL_MASK(p,x,d,s) \
3126 (PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0))))
3128 /* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask.
3130 # define S_MASKx(p,x,d,s) (S_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
3131 # define B_MASKx(p,x,d,s) (B_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
3133 /* Combine 8 of these to get the full mask. For the 1-bpp and 2-bpp
3134 * cases the result needs replicating, for the 4-bpp case the above
3135 * generates a full 32 bits.
3137 # define MASK_EXPAND(m,d) ((m)*((d)==1?0x01010101:((d)==2?0x00010001:1)))
3139 # define S_MASK(p,d,s) MASK_EXPAND(S_MASKx(p,0,d,s) + S_MASKx(p,1,d,s) +\
3140 S_MASKx(p,2,d,s) + S_MASKx(p,3,d,s) + S_MASKx(p,4,d,s) +\
3141 S_MASKx(p,5,d,s) + S_MASKx(p,6,d,s) + S_MASKx(p,7,d,s), d)
3143 # define B_MASK(p,d,s) MASK_EXPAND(B_MASKx(p,0,d,s) + B_MASKx(p,1,d,s) +\
3144 B_MASKx(p,2,d,s) + B_MASKx(p,3,d,s) + B_MASKx(p,4,d,s) +\
3145 B_MASKx(p,5,d,s) + B_MASKx(p,6,d,s) + B_MASKx(p,7,d,s), d)
3147 #if PNG_USE_COMPILE_TIME_MASKS
3148 /* Utility macros to construct all the masks for a depth/swap
3149 * combination. The 's' parameter says whether the format is PNG
3150 * (big endian bytes) or not. Only the three odd-numbered passes are
3151 * required for the display/block algorithm.
3153 # define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\
3154 S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) }
3156 # define B_MASKS(d,s) { B_MASK(1,d,s), B_MASK(3,d,s), B_MASK(5,d,s) }
3158 # define DEPTH_INDEX(d) ((d)==1?0:((d)==2?1:2))
3160 /* Hence the pre-compiled masks indexed by PACKSWAP (or not), depth and
3163 static PNG_CONST png_uint_32 row_mask[2/*PACKSWAP*/][3/*depth*/][6] =
3165 /* Little-endian byte masks for PACKSWAP */
3166 { S_MASKS(1,0), S_MASKS(2,0), S_MASKS(4,0) },
3167 /* Normal (big-endian byte) masks - PNG format */
3168 { S_MASKS(1,1), S_MASKS(2,1), S_MASKS(4,1) }
3171 /* display_mask has only three entries for the odd passes, so index by
3174 static PNG_CONST png_uint_32 display_mask[2][3][3] =
3176 /* Little-endian byte masks for PACKSWAP */
3177 { B_MASKS(1,0), B_MASKS(2,0), B_MASKS(4,0) },
3178 /* Normal (big-endian byte) masks - PNG format */
3179 { B_MASKS(1,1), B_MASKS(2,1), B_MASKS(4,1) }
3182 # define MASK(pass,depth,display,png)\
3183 ((display)?display_mask[png][DEPTH_INDEX(depth)][pass>>1]:\
3184 row_mask[png][DEPTH_INDEX(depth)][pass])
3186 #else /* !PNG_USE_COMPILE_TIME_MASKS */
3187 /* This is the runtime alternative: it seems unlikely that this will
3188 * ever be either smaller or faster than the compile time approach.
3190 # define MASK(pass,depth,display,png)\
3191 ((display)?B_MASK(pass,depth,png):S_MASK(pass,depth,png))
3192 #endif /* !PNG_USE_COMPILE_TIME_MASKS */
3194 /* Use the appropriate mask to copy the required bits. In some cases
3195 * the byte mask will be 0 or 0xff; optimize these cases. row_width is
3196 * the number of pixels, but the code copies bytes, so it is necessary
3197 * to special case the end.
3199 png_uint_32 pixels_per_byte = 8 / pixel_depth;
3202 # ifdef PNG_READ_PACKSWAP_SUPPORTED
3203 if (png_ptr->transformations & PNG_PACKSWAP)
3204 mask = MASK(pass, pixel_depth, display, 0);
3208 mask = MASK(pass, pixel_depth, display, 1);
3214 /* It doesn't matter in the following if png_uint_32 has more than
3215 * 32 bits because the high bits always match those in m<<24; it is,
3216 * however, essential to use OR here, not +, because of this.
3219 mask = (m >> 8) | (m << 24); /* rotate right to good compilers */
3222 if (m != 0) /* something to copy */
3225 *dp = (png_byte)((*dp & ~m) | (*sp & m));
3230 /* NOTE: this may overwrite the last byte with garbage if the image
3231 * is not an exact number of bytes wide; libpng has always done
3234 if (row_width <= pixels_per_byte)
3235 break; /* May need to restore part of the last byte */
3237 row_width -= pixels_per_byte;
3243 else /* pixel_depth >= 8 */
3245 unsigned int bytes_to_copy, bytes_to_jump;
3247 /* Validate the depth - it must be a multiple of 8 */
3248 if (pixel_depth & 7)
3249 png_error(png_ptr, "invalid user transform pixel depth");
3251 pixel_depth >>= 3; /* now in bytes */
3252 row_width *= pixel_depth;
3254 /* Regardless of pass number the Adam 7 interlace always results in a
3255 * fixed number of pixels to copy then to skip. There may be a
3256 * different number of pixels to skip at the start though.
3259 unsigned int offset = PNG_PASS_START_COL(pass) * pixel_depth;
3261 row_width -= offset;
3266 /* Work out the bytes to copy. */
3269 /* When doing the 'block' algorithm the pixel in the pass gets
3270 * replicated to adjacent pixels. This is why the even (0,2,4,6)
3271 * passes are skipped above - the entire expanded row is copied.
3273 bytes_to_copy = (1<<((6-pass)>>1)) * pixel_depth;
3275 /* But don't allow this number to exceed the actual row width. */
3276 if (bytes_to_copy > row_width)
3277 bytes_to_copy = row_width;
3280 else /* normal row; Adam7 only ever gives us one pixel to copy. */
3281 bytes_to_copy = pixel_depth;
3283 /* In Adam7 there is a constant offset between where the pixels go. */
3284 bytes_to_jump = PNG_PASS_COL_OFFSET(pass) * pixel_depth;
3286 /* And simply copy these bytes. Some optimization is possible here,
3287 * depending on the value of 'bytes_to_copy'. Special case the low
3288 * byte counts, which we know to be frequent.
3290 * Notice that these cases all 'return' rather than 'break' - this
3291 * avoids an unnecessary test on whether to restore the last byte
3294 switch (bytes_to_copy)
3301 if (row_width <= bytes_to_jump)
3304 dp += bytes_to_jump;
3305 sp += bytes_to_jump;
3306 row_width -= bytes_to_jump;
3310 /* There is a possibility of a partial copy at the end here; this
3311 * slows the code down somewhat.
3315 dp[0] = sp[0], dp[1] = sp[1];
3317 if (row_width <= bytes_to_jump)
3320 sp += bytes_to_jump;
3321 dp += bytes_to_jump;
3322 row_width -= bytes_to_jump;
3324 while (row_width > 1);
3326 /* And there can only be one byte left at this point: */
3331 /* This can only be the RGB case, so each copy is exactly one
3332 * pixel and it is not necessary to check for a partial copy.
3336 dp[0] = sp[0], dp[1] = sp[1], dp[2] = sp[2];
3338 if (row_width <= bytes_to_jump)
3341 sp += bytes_to_jump;
3342 dp += bytes_to_jump;
3343 row_width -= bytes_to_jump;
3347 #if PNG_ALIGN_TYPE != PNG_ALIGN_NONE
3348 /* Check for double byte alignment and, if possible, use a
3349 * 16-bit copy. Don't attempt this for narrow images - ones that
3350 * are less than an interlace panel wide. Don't attempt it for
3351 * wide bytes_to_copy either - use the memcpy there.
3353 if (bytes_to_copy < 16 /*else use memcpy*/ &&
3354 png_isaligned(dp, png_uint_16) &&
3355 png_isaligned(sp, png_uint_16) &&
3356 bytes_to_copy % (sizeof (png_uint_16)) == 0 &&
3357 bytes_to_jump % (sizeof (png_uint_16)) == 0)
3359 /* Everything is aligned for png_uint_16 copies, but try for
3360 * png_uint_32 first.
3362 if (png_isaligned(dp, png_uint_32) &&
3363 png_isaligned(sp, png_uint_32) &&
3364 bytes_to_copy % (sizeof (png_uint_32)) == 0 &&
3365 bytes_to_jump % (sizeof (png_uint_32)) == 0)
3367 png_uint_32p dp32 = png_aligncast(png_uint_32p,dp);
3368 png_const_uint_32p sp32 = png_aligncastconst(
3369 png_const_uint_32p, sp);
3370 size_t skip = (bytes_to_jump-bytes_to_copy) /
3371 (sizeof (png_uint_32));
3375 size_t c = bytes_to_copy;
3379 c -= (sizeof (png_uint_32));
3383 if (row_width <= bytes_to_jump)
3388 row_width -= bytes_to_jump;
3390 while (bytes_to_copy <= row_width);
3392 /* Get to here when the row_width truncates the final copy.
3393 * There will be 1-3 bytes left to copy, so don't try the
3394 * 16-bit loop below.
3396 dp = (png_bytep)dp32;
3397 sp = (png_const_bytep)sp32;
3400 while (--row_width > 0);
3404 /* Else do it in 16-bit quantities, but only if the size is
3409 png_uint_16p dp16 = png_aligncast(png_uint_16p, dp);
3410 png_const_uint_16p sp16 = png_aligncastconst(
3411 png_const_uint_16p, sp);
3412 size_t skip = (bytes_to_jump-bytes_to_copy) /
3413 (sizeof (png_uint_16));
3417 size_t c = bytes_to_copy;
3421 c -= (sizeof (png_uint_16));
3425 if (row_width <= bytes_to_jump)
3430 row_width -= bytes_to_jump;
3432 while (bytes_to_copy <= row_width);
3434 /* End of row - 1 byte left, bytes_to_copy > row_width: */
3435 dp = (png_bytep)dp16;
3436 sp = (png_const_bytep)sp16;
3439 while (--row_width > 0);
3443 #endif /* PNG_ALIGN_ code */
3445 /* The true default - use a memcpy: */
3448 memcpy(dp, sp, bytes_to_copy);
3450 if (row_width <= bytes_to_jump)
3453 sp += bytes_to_jump;
3454 dp += bytes_to_jump;
3455 row_width -= bytes_to_jump;
3456 if (bytes_to_copy > row_width)
3457 bytes_to_copy = row_width;
3462 } /* pixel_depth >= 8 */
3464 /* Here if pixel_depth < 8 to check 'end_ptr' below. */
3467 #endif /* PNG_READ_INTERLACING_SUPPORTED */
3469 /* If here then the switch above wasn't used so just memcpy the whole row
3470 * from the temporary row buffer (notice that this overwrites the end of the
3471 * destination row if it is a partial byte.)
3473 memcpy(dp, sp, PNG_ROWBYTES(pixel_depth, row_width));
3475 /* Restore the overwritten bits from the last byte if necessary. */
3476 if (end_ptr != NULL)
3477 *end_ptr = (png_byte)((end_byte & end_mask) | (*end_ptr & ~end_mask));
3480 #ifdef PNG_READ_INTERLACING_SUPPORTED
3482 png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
3483 png_uint_32 transformations /* Because these may affect the byte layout */)
3485 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
3486 /* Offset to next interlace block */
3487 static PNG_CONST int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
3489 png_debug(1, "in png_do_read_interlace");
3490 if (row != NULL && row_info != NULL)
3492 png_uint_32 final_width;
3494 final_width = row_info->width * png_pass_inc[pass];
3496 switch (row_info->pixel_depth)
3500 png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 3);
3501 png_bytep dp = row + (png_size_t)((final_width - 1) >> 3);
3503 int s_start, s_end, s_inc;
3504 int jstop = png_pass_inc[pass];
3509 #ifdef PNG_READ_PACKSWAP_SUPPORTED
3510 if (transformations & PNG_PACKSWAP)
3512 sshift = (int)((row_info->width + 7) & 0x07);
3513 dshift = (int)((final_width + 7) & 0x07);
3522 sshift = 7 - (int)((row_info->width + 7) & 0x07);
3523 dshift = 7 - (int)((final_width + 7) & 0x07);
3529 for (i = 0; i < row_info->width; i++)
3531 v = (png_byte)((*sp >> sshift) & 0x01);
3532 for (j = 0; j < jstop; j++)
3534 unsigned int tmp = *dp & (0x7f7f >> (7 - dshift));
3536 *dp = (png_byte)(tmp & 0xff);
3538 if (dshift == s_end)
3548 if (sshift == s_end)
3562 png_bytep sp = row + (png_uint_32)((row_info->width - 1) >> 2);
3563 png_bytep dp = row + (png_uint_32)((final_width - 1) >> 2);
3565 int s_start, s_end, s_inc;
3566 int jstop = png_pass_inc[pass];
3569 #ifdef PNG_READ_PACKSWAP_SUPPORTED
3570 if (transformations & PNG_PACKSWAP)
3572 sshift = (int)(((row_info->width + 3) & 0x03) << 1);
3573 dshift = (int)(((final_width + 3) & 0x03) << 1);
3582 sshift = (int)((3 - ((row_info->width + 3) & 0x03)) << 1);
3583 dshift = (int)((3 - ((final_width + 3) & 0x03)) << 1);
3589 for (i = 0; i < row_info->width; i++)
3594 v = (png_byte)((*sp >> sshift) & 0x03);
3595 for (j = 0; j < jstop; j++)
3597 unsigned int tmp = *dp & (0x3f3f >> (6 - dshift));
3599 *dp = (png_byte)(tmp & 0xff);
3601 if (dshift == s_end)
3611 if (sshift == s_end)
3625 png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 1);
3626 png_bytep dp = row + (png_size_t)((final_width - 1) >> 1);
3628 int s_start, s_end, s_inc;
3630 int jstop = png_pass_inc[pass];
3632 #ifdef PNG_READ_PACKSWAP_SUPPORTED
3633 if (transformations & PNG_PACKSWAP)
3635 sshift = (int)(((row_info->width + 1) & 0x01) << 2);
3636 dshift = (int)(((final_width + 1) & 0x01) << 2);
3645 sshift = (int)((1 - ((row_info->width + 1) & 0x01)) << 2);
3646 dshift = (int)((1 - ((final_width + 1) & 0x01)) << 2);
3652 for (i = 0; i < row_info->width; i++)
3654 png_byte v = (png_byte)((*sp >> sshift) & 0x0f);
3657 for (j = 0; j < jstop; j++)
3659 unsigned int tmp = *dp & (0xf0f >> (4 - dshift));
3661 *dp = (png_byte)(tmp & 0xff);
3663 if (dshift == s_end)
3673 if (sshift == s_end)
3687 png_size_t pixel_bytes = (row_info->pixel_depth >> 3);
3689 png_bytep sp = row + (png_size_t)(row_info->width - 1)
3692 png_bytep dp = row + (png_size_t)(final_width - 1) * pixel_bytes;
3694 int jstop = png_pass_inc[pass];
3697 for (i = 0; i < row_info->width; i++)
3699 png_byte v[8]; /* SAFE; pixel_depth does not exceed 64 */
3702 memcpy(v, sp, pixel_bytes);
3704 for (j = 0; j < jstop; j++)
3706 memcpy(dp, v, pixel_bytes);
3716 row_info->width = final_width;
3717 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, final_width);
3719 #ifndef PNG_READ_PACKSWAP_SUPPORTED
3720 PNG_UNUSED(transformations) /* Silence compiler warning */
3723 #endif /* PNG_READ_INTERLACING_SUPPORTED */
3726 png_read_filter_row_sub(png_row_infop row_info, png_bytep row,
3727 png_const_bytep prev_row)
3730 png_size_t istop = row_info->rowbytes;
3731 unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
3732 png_bytep rp = row + bpp;
3734 PNG_UNUSED(prev_row)
3736 for (i = bpp; i < istop; i++)
3738 *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
3744 png_read_filter_row_up(png_row_infop row_info, png_bytep row,
3745 png_const_bytep prev_row)
3748 png_size_t istop = row_info->rowbytes;
3750 png_const_bytep pp = prev_row;
3752 for (i = 0; i < istop; i++)
3754 *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
3760 png_read_filter_row_avg(png_row_infop row_info, png_bytep row,
3761 png_const_bytep prev_row)
3765 png_const_bytep pp = prev_row;
3766 unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
3767 png_size_t istop = row_info->rowbytes - bpp;
3769 for (i = 0; i < bpp; i++)
3771 *rp = (png_byte)(((int)(*rp) +
3772 ((int)(*pp++) / 2 )) & 0xff);
3777 for (i = 0; i < istop; i++)
3779 *rp = (png_byte)(((int)(*rp) +
3780 (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
3787 png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info, png_bytep row,
3788 png_const_bytep prev_row)
3790 png_bytep rp_end = row + row_info->rowbytes;
3793 /* First pixel/byte */
3796 *row++ = (png_byte)a;
3799 while (row < rp_end)
3801 int b, pa, pb, pc, p;
3803 a &= 0xff; /* From previous iteration or start */
3814 pa = p < 0 ? -p : p;
3815 pb = pc < 0 ? -pc : pc;
3816 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
3819 /* Find the best predictor, the least of pa, pb, pc favoring the earlier
3820 * ones in the case of a tie.
3822 if (pb < pa) pa = pb, a = b;
3825 /* Calculate the current pixel in a, and move the previous row pixel to c
3826 * for the next time round the loop
3830 *row++ = (png_byte)a;
3835 png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row,
3836 png_const_bytep prev_row)
3838 int bpp = (row_info->pixel_depth + 7) >> 3;
3839 png_bytep rp_end = row + bpp;
3841 /* Process the first pixel in the row completely (this is the same as 'up'
3842 * because there is only one candidate predictor for the first row).
3844 while (row < rp_end)
3846 int a = *row + *prev_row++;
3847 *row++ = (png_byte)a;
3851 rp_end += row_info->rowbytes - bpp;
3853 while (row < rp_end)
3855 int a, b, c, pa, pb, pc, p;
3857 c = *(prev_row - bpp);
3869 pa = p < 0 ? -p : p;
3870 pb = pc < 0 ? -pc : pc;
3871 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
3874 if (pb < pa) pa = pb, a = b;
3878 *row++ = (png_byte)a;
3883 png_init_filter_functions(png_structrp pp)
3884 /* This function is called once for every PNG image (except for PNG images
3885 * that only use PNG_FILTER_VALUE_NONE for all rows) to set the
3886 * implementations required to reverse the filtering of PNG rows. Reversing
3887 * the filter is the first transformation performed on the row data. It is
3888 * performed in place, therefore an implementation can be selected based on
3889 * the image pixel format. If the implementation depends on image width then
3890 * take care to ensure that it works correctly if the image is interlaced -
3891 * interlacing causes the actual row width to vary.
3894 unsigned int bpp = (pp->pixel_depth + 7) >> 3;
3896 pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub;
3897 pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up;
3898 pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg;
3900 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
3901 png_read_filter_row_paeth_1byte_pixel;
3903 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
3904 png_read_filter_row_paeth_multibyte_pixel;
3906 #ifdef PNG_FILTER_OPTIMIZATIONS
3907 /* To use this define PNG_FILTER_OPTIMIZATIONS as the name of a function to
3908 * call to install hardware optimizations for the above functions; simply
3909 * replace whatever elements of the pp->read_filter[] array with a hardware
3910 * specific (or, for that matter, generic) optimization.
3912 * To see an example of this examine what configure.ac does when
3913 * --enable-arm-neon is specified on the command line.
3915 PNG_FILTER_OPTIMIZATIONS(pp, bpp);
3920 png_read_filter_row(png_structrp pp, png_row_infop row_info, png_bytep row,
3921 png_const_bytep prev_row, int filter)
3923 /* OPTIMIZATION: DO NOT MODIFY THIS FUNCTION, instead #define
3924 * PNG_FILTER_OPTIMIZATIONS to a function that overrides the generic
3925 * implementations. See png_init_filter_functions above.
3927 if (filter > PNG_FILTER_VALUE_NONE && filter < PNG_FILTER_VALUE_LAST)
3929 if (pp->read_filter[0] == NULL)
3930 png_init_filter_functions(pp);
3932 pp->read_filter[filter-1](row_info, row, prev_row);
3936 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
3938 png_read_IDAT_data(png_structrp png_ptr, png_bytep output,
3939 png_alloc_size_t avail_out)
3941 /* Loop reading IDATs and decompressing the result into output[avail_out] */
3942 png_ptr->zstream.next_out = output;
3943 png_ptr->zstream.avail_out = 0; /* safety: set below */
3951 png_byte tmpbuf[PNG_INFLATE_BUF_SIZE];
3953 if (png_ptr->zstream.avail_in == 0)
3958 while (png_ptr->idat_size == 0)
3960 png_crc_finish(png_ptr, 0);
3962 png_ptr->idat_size = png_read_chunk_header(png_ptr);
3963 /* This is an error even in the 'check' case because the code just
3964 * consumed a non-IDAT header.
3966 if (png_ptr->chunk_name != png_IDAT)
3967 png_error(png_ptr, "Not enough image data");
3970 avail_in = png_ptr->IDAT_read_size;
3972 if (avail_in > png_ptr->idat_size)
3973 avail_in = (uInt)png_ptr->idat_size;
3975 /* A PNG with a gradually increasing IDAT size will defeat this attempt
3976 * to minimize memory usage by causing lots of re-allocs, but
3977 * realistically doing IDAT_read_size re-allocs is not likely to be a
3980 buffer = png_read_buffer(png_ptr, avail_in, 0/*error*/);
3982 png_crc_read(png_ptr, buffer, avail_in);
3983 png_ptr->idat_size -= avail_in;
3985 png_ptr->zstream.next_in = buffer;
3986 png_ptr->zstream.avail_in = avail_in;
3989 /* And set up the output side. */
3990 if (output != NULL) /* standard read */
3992 uInt out = ZLIB_IO_MAX;
3994 if (out > avail_out)
3995 out = (uInt)avail_out;
3998 png_ptr->zstream.avail_out = out;
4001 else /* after last row, checking for end */
4003 png_ptr->zstream.next_out = tmpbuf;
4004 png_ptr->zstream.avail_out = (sizeof tmpbuf);
4007 /* Use NO_FLUSH; this gives zlib the maximum opportunity to optimize the
4008 * process. If the LZ stream is truncated the sequential reader will
4009 * terminally damage the stream, above, by reading the chunk header of the
4010 * following chunk (it then exits with png_error).
4012 * TODO: deal more elegantly with truncated IDAT lists.
4014 ret = inflate(&png_ptr->zstream, Z_NO_FLUSH);
4016 /* Take the unconsumed output back. */
4018 avail_out += png_ptr->zstream.avail_out;
4020 else /* avail_out counts the extra bytes */
4021 avail_out += (sizeof tmpbuf) - png_ptr->zstream.avail_out;
4023 png_ptr->zstream.avail_out = 0;
4025 if (ret == Z_STREAM_END)
4027 /* Do this for safety; we won't read any more into this row. */
4028 png_ptr->zstream.next_out = NULL;
4030 png_ptr->mode |= PNG_AFTER_IDAT;
4031 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
4033 if (png_ptr->zstream.avail_in > 0 || png_ptr->idat_size > 0)
4034 png_chunk_benign_error(png_ptr, "Extra compressed data");
4040 png_zstream_error(png_ptr, ret);
4043 png_chunk_error(png_ptr, png_ptr->zstream.msg);
4047 png_chunk_benign_error(png_ptr, png_ptr->zstream.msg);
4051 } while (avail_out > 0);
4055 /* The stream ended before the image; this is the same as too few IDATs so
4056 * should be handled the same way.
4059 png_error(png_ptr, "Not enough image data");
4061 else /* the deflate stream contained extra data */
4062 png_chunk_benign_error(png_ptr, "Too much image data");
4067 png_read_finish_IDAT(png_structrp png_ptr)
4069 /* We don't need any more data and the stream should have ended, however the
4070 * LZ end code may actually not have been processed. In this case we must
4071 * read it otherwise stray unread IDAT data or, more likely, an IDAT chunk
4072 * may still remain to be consumed.
4074 if (!(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED))
4076 /* The NULL causes png_read_IDAT_data to swallow any remaining bytes in
4077 * the compressed stream, but the stream may be damaged too, so even after
4078 * this call we may need to terminate the zstream ownership.
4080 png_read_IDAT_data(png_ptr, NULL, 0);
4081 png_ptr->zstream.next_out = NULL; /* safety */
4083 /* Now clear everything out for safety; the following may not have been
4086 if (!(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED))
4088 png_ptr->mode |= PNG_AFTER_IDAT;
4089 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
4093 /* If the zstream has not been released do it now *and* terminate the reading
4094 * of the final IDAT chunk.
4096 if (png_ptr->zowner == png_IDAT)
4098 /* Always do this; the pointers otherwise point into the read buffer. */
4099 png_ptr->zstream.next_in = NULL;
4100 png_ptr->zstream.avail_in = 0;
4102 /* Now we no longer own the zstream. */
4103 png_ptr->zowner = 0;
4105 /* The slightly weird semantics of the sequential IDAT reading is that we
4106 * are always in or at the end of an IDAT chunk, so we always need to do a
4107 * crc_finish here. If idat_size is non-zero we also need to read the
4108 * spurious bytes at the end of the chunk now.
4110 (void)png_crc_finish(png_ptr, png_ptr->idat_size);
4115 png_read_finish_row(png_structrp png_ptr)
4117 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
4119 /* Start of interlace block */
4120 static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
4122 /* Offset to next interlace block */
4123 static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
4125 /* Start of interlace block in the y direction */
4126 static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
4128 /* Offset to next interlace block in the y direction */
4129 static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
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 if (png_ptr->interlaced)
4138 png_ptr->row_number = 0;
4140 /* TO DO: don't do this if prev_row isn't needed (requires
4141 * read-ahead of the next row's filter byte.
4143 memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
4149 if (png_ptr->pass >= 7)
4152 png_ptr->iwidth = (png_ptr->width +
4153 png_pass_inc[png_ptr->pass] - 1 -
4154 png_pass_start[png_ptr->pass]) /
4155 png_pass_inc[png_ptr->pass];
4157 if (!(png_ptr->transformations & PNG_INTERLACE))
4159 png_ptr->num_rows = (png_ptr->height +
4160 png_pass_yinc[png_ptr->pass] - 1 -
4161 png_pass_ystart[png_ptr->pass]) /
4162 png_pass_yinc[png_ptr->pass];
4165 else /* if (png_ptr->transformations & PNG_INTERLACE) */
4166 break; /* libpng deinterlacing sees every row */
4168 } while (png_ptr->num_rows == 0 || png_ptr->iwidth == 0);
4170 if (png_ptr->pass < 7)
4174 /* Here after at the end of the last row of the last pass. */
4175 png_read_finish_IDAT(png_ptr);
4177 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
4180 png_read_start_row(png_structrp png_ptr)
4182 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
4184 /* Start of interlace block */
4185 static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
4187 /* Offset to next interlace block */
4188 static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
4190 /* Start of interlace block in the y direction */
4191 static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
4193 /* Offset to next interlace block in the y direction */
4194 static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
4196 int max_pixel_depth;
4197 png_size_t row_bytes;
4199 png_debug(1, "in png_read_start_row");
4201 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
4202 png_init_read_transformations(png_ptr);
4204 if (png_ptr->interlaced)
4206 if (!(png_ptr->transformations & PNG_INTERLACE))
4207 png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
4208 png_pass_ystart[0]) / png_pass_yinc[0];
4211 png_ptr->num_rows = png_ptr->height;
4213 png_ptr->iwidth = (png_ptr->width +
4214 png_pass_inc[png_ptr->pass] - 1 -
4215 png_pass_start[png_ptr->pass]) /
4216 png_pass_inc[png_ptr->pass];
4221 png_ptr->num_rows = png_ptr->height;
4222 png_ptr->iwidth = png_ptr->width;
4225 max_pixel_depth = png_ptr->pixel_depth;
4227 /* WARNING: * png_read_transform_info (pngrtran.c) performs a simpliar set of
4228 * calculations to calculate the final pixel depth, then
4229 * png_do_read_transforms actually does the transforms. This means that the
4230 * code which effectively calculates this value is actually repeated in three
4231 * separate places. They must all match. Innocent changes to the order of
4232 * transformations can and will break libpng in a way that causes memory
4237 #ifdef PNG_READ_PACK_SUPPORTED
4238 if ((png_ptr->transformations & PNG_PACK) && png_ptr->bit_depth < 8)
4239 max_pixel_depth = 8;
4242 #ifdef PNG_READ_EXPAND_SUPPORTED
4243 if (png_ptr->transformations & PNG_EXPAND)
4245 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
4247 if (png_ptr->num_trans)
4248 max_pixel_depth = 32;
4251 max_pixel_depth = 24;
4254 else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
4256 if (max_pixel_depth < 8)
4257 max_pixel_depth = 8;
4259 if (png_ptr->num_trans)
4260 max_pixel_depth *= 2;
4263 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
4265 if (png_ptr->num_trans)
4267 max_pixel_depth *= 4;
4268 max_pixel_depth /= 3;
4274 #ifdef PNG_READ_EXPAND_16_SUPPORTED
4275 if (png_ptr->transformations & PNG_EXPAND_16)
4277 # ifdef PNG_READ_EXPAND_SUPPORTED
4278 /* In fact it is an error if it isn't supported, but checking is
4281 if (png_ptr->transformations & PNG_EXPAND)
4283 if (png_ptr->bit_depth < 16)
4284 max_pixel_depth *= 2;
4288 png_ptr->transformations &= ~PNG_EXPAND_16;
4292 #ifdef PNG_READ_FILLER_SUPPORTED
4293 if (png_ptr->transformations & (PNG_FILLER))
4295 if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
4297 if (max_pixel_depth <= 8)
4298 max_pixel_depth = 16;
4301 max_pixel_depth = 32;
4304 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB ||
4305 png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
4307 if (max_pixel_depth <= 32)
4308 max_pixel_depth = 32;
4311 max_pixel_depth = 64;
4316 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
4317 if (png_ptr->transformations & PNG_GRAY_TO_RGB)
4320 #ifdef PNG_READ_EXPAND_SUPPORTED
4321 (png_ptr->num_trans && (png_ptr->transformations & PNG_EXPAND)) ||
4323 #ifdef PNG_READ_FILLER_SUPPORTED
4324 (png_ptr->transformations & (PNG_FILLER)) ||
4326 png_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
4328 if (max_pixel_depth <= 16)
4329 max_pixel_depth = 32;
4332 max_pixel_depth = 64;
4337 if (max_pixel_depth <= 8)
4339 if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
4340 max_pixel_depth = 32;
4343 max_pixel_depth = 24;
4346 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
4347 max_pixel_depth = 64;
4350 max_pixel_depth = 48;
4355 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) && \
4356 defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
4357 if (png_ptr->transformations & PNG_USER_TRANSFORM)
4359 int user_pixel_depth = png_ptr->user_transform_depth *
4360 png_ptr->user_transform_channels;
4362 if (user_pixel_depth > max_pixel_depth)
4363 max_pixel_depth = user_pixel_depth;
4367 /* This value is stored in png_struct and double checked in the row read
4370 png_ptr->maximum_pixel_depth = (png_byte)max_pixel_depth;
4371 png_ptr->transformed_pixel_depth = 0; /* calculated on demand */
4373 /* Align the width on the next larger 8 pixels. Mainly used
4376 row_bytes = ((png_ptr->width + 7) & ~((png_uint_32)7));
4377 /* Calculate the maximum bytes needed, adding a byte and a pixel
4380 row_bytes = PNG_ROWBYTES(max_pixel_depth, row_bytes) +
4381 1 + ((max_pixel_depth + 7) >> 3);
4383 #ifdef PNG_MAX_MALLOC_64K
4384 if (row_bytes > (png_uint_32)65536L)
4385 png_error(png_ptr, "This image requires a row greater than 64KB");
4388 if (row_bytes + 48 > png_ptr->old_big_row_buf_size)
4390 png_free(png_ptr, png_ptr->big_row_buf);
4391 png_free(png_ptr, png_ptr->big_prev_row);
4393 if (png_ptr->interlaced)
4394 png_ptr->big_row_buf = (png_bytep)png_calloc(png_ptr,
4398 png_ptr->big_row_buf = (png_bytep)png_malloc(png_ptr, row_bytes + 48);
4400 png_ptr->big_prev_row = (png_bytep)png_malloc(png_ptr, row_bytes + 48);
4402 #ifdef PNG_ALIGNED_MEMORY_SUPPORTED
4403 /* Use 16-byte aligned memory for row_buf with at least 16 bytes
4404 * of padding before and after row_buf; treat prev_row similarly.
4405 * NOTE: the alignment is to the start of the pixels, one beyond the start
4406 * of the buffer, because of the filter byte. Prior to libpng 1.5.6 this
4407 * was incorrect; the filter byte was aligned, which had the exact
4408 * opposite effect of that intended.
4411 png_bytep temp = png_ptr->big_row_buf + 32;
4412 int extra = (int)((temp - (png_bytep)0) & 0x0f);
4413 png_ptr->row_buf = temp - extra - 1/*filter byte*/;
4415 temp = png_ptr->big_prev_row + 32;
4416 extra = (int)((temp - (png_bytep)0) & 0x0f);
4417 png_ptr->prev_row = temp - extra - 1/*filter byte*/;
4421 /* Use 31 bytes of padding before and 17 bytes after row_buf. */
4422 png_ptr->row_buf = png_ptr->big_row_buf + 31;
4423 png_ptr->prev_row = png_ptr->big_prev_row + 31;
4425 png_ptr->old_big_row_buf_size = row_bytes + 48;
4428 #ifdef PNG_MAX_MALLOC_64K
4429 if (png_ptr->rowbytes > 65535)
4430 png_error(png_ptr, "This image requires a row greater than 64KB");
4433 if (png_ptr->rowbytes > (PNG_SIZE_MAX - 1))
4434 png_error(png_ptr, "Row has too many bytes to allocate in memory");
4436 memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
4438 png_debug1(3, "width = %u,", png_ptr->width);
4439 png_debug1(3, "height = %u,", png_ptr->height);
4440 png_debug1(3, "iwidth = %u,", png_ptr->iwidth);
4441 png_debug1(3, "num_rows = %u,", png_ptr->num_rows);
4442 png_debug1(3, "rowbytes = %lu,", (unsigned long)png_ptr->rowbytes);
4443 png_debug1(3, "irowbytes = %lu",
4444 (unsigned long)PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->iwidth) + 1);
4446 /* The sequential reader needs a buffer for IDAT, but the progressive reader
4447 * does not, so free the read buffer now regardless; the sequential reader
4448 * reallocates it on demand.
4450 if (png_ptr->read_buffer)
4452 png_bytep buffer = png_ptr->read_buffer;
4454 png_ptr->read_buffer_size = 0;
4455 png_ptr->read_buffer = NULL;
4456 png_free(png_ptr, buffer);
4459 /* Finally claim the zstream for the inflate of the IDAT data, use the bits
4460 * value from the stream (note that this will result in a fatal error if the
4461 * IDAT stream has a bogus deflate header window_bits value, but this should
4462 * not be happening any longer!)
4464 if (png_inflate_claim(png_ptr, png_IDAT) != Z_OK)
4465 png_error(png_ptr, png_ptr->zstream.msg);
4467 png_ptr->flags |= PNG_FLAG_ROW_INIT;
4469 #endif /* PNG_READ_SUPPORTED */