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