2 /* pngrutil.c - utilities to read a PNG file
4 * Copyright (c) 2018 Cosmin Truta
5 * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
6 * Copyright (c) 1996-1997 Andreas Dilger
7 * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
9 * This code is released under the libpng license.
10 * For conditions of distribution and use, see the disclaimer
11 * and license in png.h
13 * This file contains routines that are only called from within
14 * libpng itself during the course of reading an image.
22 #ifdef PNG_READ_SUPPORTED
25 png_get_uint_31(png_const_structrp png_ptr, png_const_bytep buf)
27 png_uint_32 uval = png_get_uint_32(buf);
29 if (uval > PNG_UINT_31_MAX)
30 png_error(png_ptr, "PNG unsigned integer out of range");
35 #if defined(PNG_READ_gAMA_SUPPORTED) || defined(PNG_READ_cHRM_SUPPORTED)
36 /* The following is a variation on the above for use with the fixed
37 * point values used for gAMA and cHRM. Instead of png_error it
38 * issues a warning and returns (-1) - an invalid value because both
39 * gAMA and cHRM use *unsigned* integers for fixed point values.
41 #define PNG_FIXED_ERROR (-1)
43 static png_fixed_point /* PRIVATE */
44 png_get_fixed_point(png_structrp png_ptr, png_const_bytep buf)
46 png_uint_32 uval = png_get_uint_32(buf);
48 if (uval <= PNG_UINT_31_MAX)
49 return (png_fixed_point)uval; /* known to be in range */
51 /* The caller can turn off the warning by passing NULL. */
53 png_warning(png_ptr, "PNG fixed point integer out of range");
55 return PNG_FIXED_ERROR;
59 #ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
60 /* NOTE: the read macros will obscure these definitions, so that if
61 * PNG_USE_READ_MACROS is set the library will not use them internally,
62 * but the APIs will still be available externally.
64 * The parentheses around "PNGAPI function_name" in the following three
65 * functions are necessary because they allow the macros to co-exist with
66 * these (unused but exported) functions.
69 /* Grab an unsigned 32-bit integer from a buffer in big-endian format. */
71 png_get_uint_32)(png_const_bytep buf)
74 ((png_uint_32)(*(buf )) << 24) +
75 ((png_uint_32)(*(buf + 1)) << 16) +
76 ((png_uint_32)(*(buf + 2)) << 8) +
77 ((png_uint_32)(*(buf + 3)) ) ;
82 /* Grab a signed 32-bit integer from a buffer in big-endian format. The
83 * data is stored in the PNG file in two's complement format and there
84 * is no guarantee that a 'png_int_32' is exactly 32 bits, therefore
85 * the following code does a two's complement to native conversion.
88 png_get_int_32)(png_const_bytep buf)
90 png_uint_32 uval = png_get_uint_32(buf);
91 if ((uval & 0x80000000) == 0) /* non-negative */
92 return (png_int_32)uval;
94 uval = (uval ^ 0xffffffff) + 1; /* 2's complement: -x = ~x+1 */
95 if ((uval & 0x80000000) == 0) /* no overflow */
96 return -(png_int_32)uval;
97 /* The following has to be safe; this function only gets called on PNG data
98 * and if we get here that data is invalid. 0 is the most safe value and
99 * if not then an attacker would surely just generate a PNG with 0 instead.
104 /* Grab an unsigned 16-bit integer from a buffer in big-endian format. */
106 png_get_uint_16)(png_const_bytep buf)
108 /* ANSI-C requires an int value to accommodate at least 16 bits so this
109 * works and allows the compiler not to worry about possible narrowing
110 * on 32-bit systems. (Pre-ANSI systems did not make integers smaller
111 * than 16 bits either.)
114 ((unsigned int)(*buf) << 8) +
115 ((unsigned int)(*(buf + 1)));
117 return (png_uint_16)val;
120 #endif /* READ_INT_FUNCTIONS */
122 /* Read and check the PNG file signature */
124 png_read_sig(png_structrp png_ptr, png_inforp info_ptr)
126 size_t num_checked, num_to_check;
128 /* Exit if the user application does not expect a signature. */
129 if (png_ptr->sig_bytes >= 8)
132 num_checked = png_ptr->sig_bytes;
133 num_to_check = 8 - num_checked;
135 #ifdef PNG_IO_STATE_SUPPORTED
136 png_ptr->io_state = PNG_IO_READING | PNG_IO_SIGNATURE;
139 /* The signature must be serialized in a single I/O call. */
140 png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check);
141 png_ptr->sig_bytes = 8;
143 if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check) != 0)
145 if (num_checked < 4 &&
146 png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
147 png_error(png_ptr, "Not a PNG file");
149 png_error(png_ptr, "PNG file corrupted by ASCII conversion");
152 png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
155 /* Read the chunk header (length + type name).
156 * Put the type name into png_ptr->chunk_name, and return the length.
158 png_uint_32 /* PRIVATE */
159 png_read_chunk_header(png_structrp png_ptr)
164 #ifdef PNG_IO_STATE_SUPPORTED
165 png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_HDR;
168 /* Read the length and the chunk name.
169 * This must be performed in a single I/O call.
171 png_read_data(png_ptr, buf, 8);
172 length = png_get_uint_31(png_ptr, buf);
174 /* Put the chunk name into png_ptr->chunk_name. */
175 png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(buf+4);
177 png_debug2(0, "Reading %lx chunk, length = %lu",
178 (unsigned long)png_ptr->chunk_name, (unsigned long)length);
180 /* Reset the crc and run it over the chunk name. */
181 png_reset_crc(png_ptr);
182 png_calculate_crc(png_ptr, buf + 4, 4);
184 /* Check to see if chunk name is valid. */
185 png_check_chunk_name(png_ptr, png_ptr->chunk_name);
187 /* Check for too-large chunk length */
188 png_check_chunk_length(png_ptr, length);
190 #ifdef PNG_IO_STATE_SUPPORTED
191 png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_DATA;
197 /* Read data, and (optionally) run it through the CRC. */
199 png_crc_read(png_structrp png_ptr, png_bytep buf, png_uint_32 length)
204 png_read_data(png_ptr, buf, length);
205 png_calculate_crc(png_ptr, buf, length);
208 /* Optionally skip data and then check the CRC. Depending on whether we
209 * are reading an ancillary or critical chunk, and how the program has set
210 * things up, we may calculate the CRC on the data and print a message.
211 * Returns '1' if there was a CRC error, '0' otherwise.
214 png_crc_finish(png_structrp png_ptr, png_uint_32 skip)
216 /* The size of the local buffer for inflate is a good guess as to a
217 * reasonable size to use for buffering reads from the application.
222 png_byte tmpbuf[PNG_INFLATE_BUF_SIZE];
224 len = (sizeof tmpbuf);
229 png_crc_read(png_ptr, tmpbuf, len);
232 if (png_crc_error(png_ptr) != 0)
234 if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0 ?
235 (png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) == 0 :
236 (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_USE) != 0)
238 png_chunk_warning(png_ptr, "CRC error");
242 png_chunk_error(png_ptr, "CRC error");
250 /* Compare the CRC stored in the PNG file with that calculated by libpng from
251 * the data it has read thus far.
254 png_crc_error(png_structrp png_ptr)
256 png_byte crc_bytes[4];
260 if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0)
262 if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
263 (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
269 if ((png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) != 0)
273 #ifdef PNG_IO_STATE_SUPPORTED
274 png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_CRC;
277 /* The chunk CRC must be serialized in a single I/O call. */
278 png_read_data(png_ptr, crc_bytes, 4);
282 crc = png_get_uint_32(crc_bytes);
283 return ((int)(crc != png_ptr->crc));
290 #if defined(PNG_READ_iCCP_SUPPORTED) || defined(PNG_READ_iTXt_SUPPORTED) ||\
291 defined(PNG_READ_pCAL_SUPPORTED) || defined(PNG_READ_sCAL_SUPPORTED) ||\
292 defined(PNG_READ_sPLT_SUPPORTED) || defined(PNG_READ_tEXt_SUPPORTED) ||\
293 defined(PNG_READ_zTXt_SUPPORTED) || defined(PNG_SEQUENTIAL_READ_SUPPORTED)
294 /* Manage the read buffer; this simply reallocates the buffer if it is not small
295 * enough (or if it is not allocated). The routine returns a pointer to the
296 * buffer; if an error occurs and 'warn' is set the routine returns NULL, else
297 * it will call png_error (via png_malloc) on failure. (warn == 2 means
301 png_read_buffer(png_structrp png_ptr, png_alloc_size_t new_size, int warn)
303 png_bytep buffer = png_ptr->read_buffer;
305 if (buffer != NULL && new_size > png_ptr->read_buffer_size)
307 png_ptr->read_buffer = NULL;
308 png_ptr->read_buffer = NULL;
309 png_ptr->read_buffer_size = 0;
310 png_free(png_ptr, buffer);
316 buffer = png_voidcast(png_bytep, png_malloc_base(png_ptr, new_size));
320 memset(buffer, 0, new_size); /* just in case */
321 png_ptr->read_buffer = buffer;
322 png_ptr->read_buffer_size = new_size;
325 else if (warn < 2) /* else silent */
328 png_chunk_warning(png_ptr, "insufficient memory to read chunk");
331 png_chunk_error(png_ptr, "insufficient memory to read chunk");
337 #endif /* READ_iCCP|iTXt|pCAL|sCAL|sPLT|tEXt|zTXt|SEQUENTIAL_READ */
339 /* png_inflate_claim: claim the zstream for some nefarious purpose that involves
340 * decompression. Returns Z_OK on success, else a zlib error code. It checks
341 * the owner but, in final release builds, just issues a warning if some other
342 * chunk apparently owns the stream. Prior to release it does a png_error.
345 png_inflate_claim(png_structrp png_ptr, png_uint_32 owner)
347 if (png_ptr->zowner != 0)
351 PNG_STRING_FROM_CHUNK(msg, png_ptr->zowner);
352 /* So the message that results is "<chunk> using zstream"; this is an
353 * internal error, but is very useful for debugging. i18n requirements
356 (void)png_safecat(msg, (sizeof msg), 4, " using zstream");
357 #if PNG_RELEASE_BUILD
358 png_chunk_warning(png_ptr, msg);
361 png_chunk_error(png_ptr, msg);
365 /* Implementation note: unlike 'png_deflate_claim' this internal function
366 * does not take the size of the data as an argument. Some efficiency could
367 * be gained by using this when it is known *if* the zlib stream itself does
368 * not record the number; however, this is an illusion: the original writer
369 * of the PNG may have selected a lower window size, and we really must
370 * follow that because, for systems with with limited capabilities, we
371 * would otherwise reject the application's attempts to use a smaller window
372 * size (zlib doesn't have an interface to say "this or lower"!).
374 * inflateReset2 was added to zlib 1.2.4; before this the window could not be
375 * reset, therefore it is necessary to always allocate the maximum window
376 * size with earlier zlibs just in case later compressed chunks need it.
379 int ret; /* zlib return code */
380 #if ZLIB_VERNUM >= 0x1240
383 # if defined(PNG_SET_OPTION_SUPPORTED) && defined(PNG_MAXIMUM_INFLATE_WINDOW)
384 if (((png_ptr->options >> PNG_MAXIMUM_INFLATE_WINDOW) & 3) ==
388 png_ptr->zstream_start = 0; /* fixed window size */
393 png_ptr->zstream_start = 1;
397 #endif /* ZLIB_VERNUM >= 0x1240 */
399 /* Set this for safety, just in case the previous owner left pointers to
400 * memory allocations.
402 png_ptr->zstream.next_in = NULL;
403 png_ptr->zstream.avail_in = 0;
404 png_ptr->zstream.next_out = NULL;
405 png_ptr->zstream.avail_out = 0;
407 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
409 #if ZLIB_VERNUM >= 0x1240
410 ret = inflateReset2(&png_ptr->zstream, window_bits);
412 ret = inflateReset(&png_ptr->zstream);
418 #if ZLIB_VERNUM >= 0x1240
419 ret = inflateInit2(&png_ptr->zstream, window_bits);
421 ret = inflateInit(&png_ptr->zstream);
425 png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED;
428 #if ZLIB_VERNUM >= 0x1290 && \
429 defined(PNG_SET_OPTION_SUPPORTED) && defined(PNG_IGNORE_ADLER32)
430 if (((png_ptr->options >> PNG_IGNORE_ADLER32) & 3) == PNG_OPTION_ON)
431 /* Turn off validation of the ADLER32 checksum in IDAT chunks */
432 ret = inflateValidate(&png_ptr->zstream, 0);
436 png_ptr->zowner = owner;
439 png_zstream_error(png_ptr, ret);
449 #if ZLIB_VERNUM >= 0x1240
450 /* Handle the start of the inflate stream if we called inflateInit2(strm,0);
451 * in this case some zlib versions skip validation of the CINFO field and, in
452 * certain circumstances, libpng may end up displaying an invalid image, in
453 * contrast to implementations that call zlib in the normal way (e.g. libpng
457 png_zlib_inflate(png_structrp png_ptr, int flush)
459 if (png_ptr->zstream_start && png_ptr->zstream.avail_in > 0)
461 if ((*png_ptr->zstream.next_in >> 4) > 7)
463 png_ptr->zstream.msg = "invalid window size (libpng)";
467 png_ptr->zstream_start = 0;
470 return inflate(&png_ptr->zstream, flush);
472 #endif /* Zlib >= 1.2.4 */
474 #ifdef PNG_READ_COMPRESSED_TEXT_SUPPORTED
475 #if defined(PNG_READ_zTXt_SUPPORTED) || defined (PNG_READ_iTXt_SUPPORTED)
476 /* png_inflate now returns zlib error codes including Z_OK and Z_STREAM_END to
477 * allow the caller to do multiple calls if required. If the 'finish' flag is
478 * set Z_FINISH will be passed to the final inflate() call and Z_STREAM_END must
479 * be returned or there has been a problem, otherwise Z_SYNC_FLUSH is used and
480 * Z_OK or Z_STREAM_END will be returned on success.
482 * The input and output sizes are updated to the actual amounts of data consumed
483 * or written, not the amount available (as in a z_stream). The data pointers
484 * are not changed, so the next input is (data+input_size) and the next
485 * available output is (output+output_size).
488 png_inflate(png_structrp png_ptr, png_uint_32 owner, int finish,
489 /* INPUT: */ png_const_bytep input, png_uint_32p input_size_ptr,
490 /* OUTPUT: */ png_bytep output, png_alloc_size_t *output_size_ptr)
492 if (png_ptr->zowner == owner) /* Else not claimed */
495 png_alloc_size_t avail_out = *output_size_ptr;
496 png_uint_32 avail_in = *input_size_ptr;
498 /* zlib can't necessarily handle more than 65535 bytes at once (i.e. it
499 * can't even necessarily handle 65536 bytes) because the type uInt is
500 * "16 bits or more". Consequently it is necessary to chunk the input to
501 * zlib. This code uses ZLIB_IO_MAX, from pngpriv.h, as the maximum (the
502 * maximum value that can be stored in a uInt.) It is possible to set
503 * ZLIB_IO_MAX to a lower value in pngpriv.h and this may sometimes have
504 * a performance advantage, because it reduces the amount of data accessed
505 * at each step and that may give the OS more time to page it in.
507 png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input);
508 /* avail_in and avail_out are set below from 'size' */
509 png_ptr->zstream.avail_in = 0;
510 png_ptr->zstream.avail_out = 0;
512 /* Read directly into the output if it is available (this is set to
513 * a local buffer below if output is NULL).
516 png_ptr->zstream.next_out = output;
521 Byte local_buffer[PNG_INFLATE_BUF_SIZE];
523 /* zlib INPUT BUFFER */
524 /* The setting of 'avail_in' used to be outside the loop; by setting it
525 * inside it is possible to chunk the input to zlib and simply rely on
526 * zlib to advance the 'next_in' pointer. This allows arbitrary
527 * amounts of data to be passed through zlib at the unavoidable cost of
528 * requiring a window save (memcpy of up to 32768 output bytes)
529 * every ZLIB_IO_MAX input bytes.
531 avail_in += png_ptr->zstream.avail_in; /* not consumed last time */
535 if (avail_in < avail)
536 avail = (uInt)avail_in; /* safe: < than ZLIB_IO_MAX */
539 png_ptr->zstream.avail_in = avail;
541 /* zlib OUTPUT BUFFER */
542 avail_out += png_ptr->zstream.avail_out; /* not written last time */
544 avail = ZLIB_IO_MAX; /* maximum zlib can process */
548 /* Reset the output buffer each time round if output is NULL and
549 * make available the full buffer, up to 'remaining_space'
551 png_ptr->zstream.next_out = local_buffer;
552 if ((sizeof local_buffer) < avail)
553 avail = (sizeof local_buffer);
556 if (avail_out < avail)
557 avail = (uInt)avail_out; /* safe: < ZLIB_IO_MAX */
559 png_ptr->zstream.avail_out = avail;
562 /* zlib inflate call */
563 /* In fact 'avail_out' may be 0 at this point, that happens at the end
564 * of the read when the final LZ end code was not passed at the end of
565 * the previous chunk of input data. Tell zlib if we have reached the
566 * end of the output buffer.
568 ret = PNG_INFLATE(png_ptr, avail_out > 0 ? Z_NO_FLUSH :
569 (finish ? Z_FINISH : Z_SYNC_FLUSH));
570 } while (ret == Z_OK);
572 /* For safety kill the local buffer pointer now */
574 png_ptr->zstream.next_out = NULL;
576 /* Claw back the 'size' and 'remaining_space' byte counts. */
577 avail_in += png_ptr->zstream.avail_in;
578 avail_out += png_ptr->zstream.avail_out;
580 /* Update the input and output sizes; the updated values are the amount
581 * consumed or written, effectively the inverse of what zlib uses.
584 *output_size_ptr -= avail_out;
587 *input_size_ptr -= avail_in;
589 /* Ensure png_ptr->zstream.msg is set (even in the success case!) */
590 png_zstream_error(png_ptr, ret);
596 /* This is a bad internal error. The recovery assigns to the zstream msg
597 * pointer, which is not owned by the caller, but this is safe; it's only
600 png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed");
601 return Z_STREAM_ERROR;
606 * Decompress trailing data in a chunk. The assumption is that read_buffer
607 * points at an allocated area holding the contents of a chunk with a
608 * trailing compressed part. What we get back is an allocated area
609 * holding the original prefix part and an uncompressed version of the
610 * trailing part (the malloc area passed in is freed).
613 png_decompress_chunk(png_structrp png_ptr,
614 png_uint_32 chunklength, png_uint_32 prefix_size,
615 png_alloc_size_t *newlength /* must be initialized to the maximum! */,
616 int terminate /*add a '\0' to the end of the uncompressed data*/)
618 /* TODO: implement different limits for different types of chunk.
620 * The caller supplies *newlength set to the maximum length of the
621 * uncompressed data, but this routine allocates space for the prefix and
622 * maybe a '\0' terminator too. We have to assume that 'prefix_size' is
623 * limited only by the maximum chunk size.
625 png_alloc_size_t limit = PNG_SIZE_MAX;
627 # ifdef PNG_SET_USER_LIMITS_SUPPORTED
628 if (png_ptr->user_chunk_malloc_max > 0 &&
629 png_ptr->user_chunk_malloc_max < limit)
630 limit = png_ptr->user_chunk_malloc_max;
631 # elif PNG_USER_CHUNK_MALLOC_MAX > 0
632 if (PNG_USER_CHUNK_MALLOC_MAX < limit)
633 limit = PNG_USER_CHUNK_MALLOC_MAX;
636 if (limit >= prefix_size + (terminate != 0))
640 limit -= prefix_size + (terminate != 0);
642 if (limit < *newlength)
645 /* Now try to claim the stream. */
646 ret = png_inflate_claim(png_ptr, png_ptr->chunk_name);
650 png_uint_32 lzsize = chunklength - prefix_size;
652 ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/,
653 /* input: */ png_ptr->read_buffer + prefix_size, &lzsize,
654 /* output: */ NULL, newlength);
656 if (ret == Z_STREAM_END)
658 /* Use 'inflateReset' here, not 'inflateReset2' because this
659 * preserves the previously decided window size (otherwise it would
660 * be necessary to store the previous window size.) In practice
661 * this doesn't matter anyway, because png_inflate will call inflate
662 * with Z_FINISH in almost all cases, so the window will not be
665 if (inflateReset(&png_ptr->zstream) == Z_OK)
667 /* Because of the limit checks above we know that the new,
668 * expanded, size will fit in a size_t (let alone an
669 * png_alloc_size_t). Use png_malloc_base here to avoid an
672 png_alloc_size_t new_size = *newlength;
673 png_alloc_size_t buffer_size = prefix_size + new_size +
675 png_bytep text = png_voidcast(png_bytep, png_malloc_base(png_ptr,
680 memset(text, 0, buffer_size);
682 ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/,
683 png_ptr->read_buffer + prefix_size, &lzsize,
684 text + prefix_size, newlength);
686 if (ret == Z_STREAM_END)
688 if (new_size == *newlength)
691 text[prefix_size + *newlength] = 0;
694 memcpy(text, png_ptr->read_buffer, prefix_size);
697 png_bytep old_ptr = png_ptr->read_buffer;
699 png_ptr->read_buffer = text;
700 png_ptr->read_buffer_size = buffer_size;
701 text = old_ptr; /* freed below */
707 /* The size changed on the second read, there can be no
708 * guarantee that anything is correct at this point.
709 * The 'msg' pointer has been set to "unexpected end of
710 * LZ stream", which is fine, but return an error code
711 * that the caller won't accept.
713 ret = PNG_UNEXPECTED_ZLIB_RETURN;
717 else if (ret == Z_OK)
718 ret = PNG_UNEXPECTED_ZLIB_RETURN; /* for safety */
720 /* Free the text pointer (this is the old read_buffer on
723 png_free(png_ptr, text);
725 /* This really is very benign, but it's still an error because
726 * the extra space may otherwise be used as a Trojan Horse.
728 if (ret == Z_STREAM_END &&
729 chunklength - prefix_size != lzsize)
730 png_chunk_benign_error(png_ptr, "extra compressed data");
735 /* Out of memory allocating the buffer */
737 png_zstream_error(png_ptr, Z_MEM_ERROR);
743 /* inflateReset failed, store the error message */
744 png_zstream_error(png_ptr, ret);
745 ret = PNG_UNEXPECTED_ZLIB_RETURN;
749 else if (ret == Z_OK)
750 ret = PNG_UNEXPECTED_ZLIB_RETURN;
752 /* Release the claimed stream */
756 else /* the claim failed */ if (ret == Z_STREAM_END) /* impossible! */
757 ret = PNG_UNEXPECTED_ZLIB_RETURN;
764 /* Application/configuration limits exceeded */
765 png_zstream_error(png_ptr, Z_MEM_ERROR);
769 #endif /* READ_zTXt || READ_iTXt */
770 #endif /* READ_COMPRESSED_TEXT */
772 #ifdef PNG_READ_iCCP_SUPPORTED
773 /* Perform a partial read and decompress, producing 'avail_out' bytes and
774 * reading from the current chunk as required.
777 png_inflate_read(png_structrp png_ptr, png_bytep read_buffer, uInt read_size,
778 png_uint_32p chunk_bytes, png_bytep next_out, png_alloc_size_t *out_size,
781 if (png_ptr->zowner == png_ptr->chunk_name)
785 /* next_in and avail_in must have been initialized by the caller. */
786 png_ptr->zstream.next_out = next_out;
787 png_ptr->zstream.avail_out = 0; /* set in the loop */
791 if (png_ptr->zstream.avail_in == 0)
793 if (read_size > *chunk_bytes)
794 read_size = (uInt)*chunk_bytes;
795 *chunk_bytes -= read_size;
798 png_crc_read(png_ptr, read_buffer, read_size);
800 png_ptr->zstream.next_in = read_buffer;
801 png_ptr->zstream.avail_in = read_size;
804 if (png_ptr->zstream.avail_out == 0)
806 uInt avail = ZLIB_IO_MAX;
807 if (avail > *out_size)
808 avail = (uInt)*out_size;
811 png_ptr->zstream.avail_out = avail;
814 /* Use Z_SYNC_FLUSH when there is no more chunk data to ensure that all
815 * the available output is produced; this allows reading of truncated
818 ret = PNG_INFLATE(png_ptr, *chunk_bytes > 0 ?
819 Z_NO_FLUSH : (finish ? Z_FINISH : Z_SYNC_FLUSH));
821 while (ret == Z_OK && (*out_size > 0 || png_ptr->zstream.avail_out > 0));
823 *out_size += png_ptr->zstream.avail_out;
824 png_ptr->zstream.avail_out = 0; /* Should not be required, but is safe */
826 /* Ensure the error message pointer is always set: */
827 png_zstream_error(png_ptr, ret);
833 png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed");
834 return Z_STREAM_ERROR;
837 #endif /* READ_iCCP */
839 /* Read and check the IDHR chunk */
842 png_handle_IHDR(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
845 png_uint_32 width, height;
846 int bit_depth, color_type, compression_type, filter_type;
849 png_debug(1, "in png_handle_IHDR");
851 if ((png_ptr->mode & PNG_HAVE_IHDR) != 0)
852 png_chunk_error(png_ptr, "out of place");
854 /* Check the length */
856 png_chunk_error(png_ptr, "invalid");
858 png_ptr->mode |= PNG_HAVE_IHDR;
860 png_crc_read(png_ptr, buf, 13);
861 png_crc_finish(png_ptr, 0);
863 width = png_get_uint_31(png_ptr, buf);
864 height = png_get_uint_31(png_ptr, buf + 4);
867 compression_type = buf[10];
868 filter_type = buf[11];
869 interlace_type = buf[12];
871 #ifdef PNG_READ_APNG_SUPPORTED
872 png_ptr->first_frame_width = width;
873 png_ptr->first_frame_height = height;
876 /* Set internal variables */
877 png_ptr->width = width;
878 png_ptr->height = height;
879 png_ptr->bit_depth = (png_byte)bit_depth;
880 png_ptr->interlaced = (png_byte)interlace_type;
881 png_ptr->color_type = (png_byte)color_type;
882 #ifdef PNG_MNG_FEATURES_SUPPORTED
883 png_ptr->filter_type = (png_byte)filter_type;
885 png_ptr->compression_type = (png_byte)compression_type;
887 /* Find number of channels */
888 switch (png_ptr->color_type)
890 default: /* invalid, png_set_IHDR calls png_error */
891 case PNG_COLOR_TYPE_GRAY:
892 case PNG_COLOR_TYPE_PALETTE:
893 png_ptr->channels = 1;
896 case PNG_COLOR_TYPE_RGB:
897 png_ptr->channels = 3;
900 case PNG_COLOR_TYPE_GRAY_ALPHA:
901 png_ptr->channels = 2;
904 case PNG_COLOR_TYPE_RGB_ALPHA:
905 png_ptr->channels = 4;
909 /* Set up other useful info */
910 png_ptr->pixel_depth = (png_byte)(png_ptr->bit_depth * png_ptr->channels);
911 png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->width);
912 png_debug1(3, "bit_depth = %d", png_ptr->bit_depth);
913 png_debug1(3, "channels = %d", png_ptr->channels);
914 png_debug1(3, "rowbytes = %lu", (unsigned long)png_ptr->rowbytes);
915 png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth,
916 color_type, interlace_type, compression_type, filter_type);
919 /* Read and check the palette */
921 png_handle_PLTE(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
923 png_color palette[PNG_MAX_PALETTE_LENGTH];
924 int max_palette_length, num, i;
925 #ifdef PNG_POINTER_INDEXING_SUPPORTED
929 png_debug(1, "in png_handle_PLTE");
931 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
932 png_chunk_error(png_ptr, "missing IHDR");
934 /* Moved to before the 'after IDAT' check below because otherwise duplicate
935 * PLTE chunks are potentially ignored (the spec says there shall not be more
936 * than one PLTE, the error is not treated as benign, so this check trumps
937 * the requirement that PLTE appears before IDAT.)
939 else if ((png_ptr->mode & PNG_HAVE_PLTE) != 0)
940 png_chunk_error(png_ptr, "duplicate");
942 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
944 /* This is benign because the non-benign error happened before, when an
945 * IDAT was encountered in a color-mapped image with no PLTE.
947 png_crc_finish(png_ptr, length);
948 png_chunk_benign_error(png_ptr, "out of place");
952 png_ptr->mode |= PNG_HAVE_PLTE;
954 if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
956 png_crc_finish(png_ptr, length);
957 png_chunk_benign_error(png_ptr, "ignored in grayscale PNG");
961 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
962 if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
964 png_crc_finish(png_ptr, length);
969 if (length > 3*PNG_MAX_PALETTE_LENGTH || length % 3)
971 png_crc_finish(png_ptr, length);
973 if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
974 png_chunk_benign_error(png_ptr, "invalid");
977 png_chunk_error(png_ptr, "invalid");
982 /* The cast is safe because 'length' is less than 3*PNG_MAX_PALETTE_LENGTH */
983 num = (int)length / 3;
985 /* If the palette has 256 or fewer entries but is too large for the bit
986 * depth, we don't issue an error, to preserve the behavior of previous
987 * libpng versions. We silently truncate the unused extra palette entries
990 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
991 max_palette_length = (1 << png_ptr->bit_depth);
993 max_palette_length = PNG_MAX_PALETTE_LENGTH;
995 if (num > max_palette_length)
996 num = max_palette_length;
998 #ifdef PNG_POINTER_INDEXING_SUPPORTED
999 for (i = 0, pal_ptr = palette; i < num; i++, pal_ptr++)
1003 png_crc_read(png_ptr, buf, 3);
1004 pal_ptr->red = buf[0];
1005 pal_ptr->green = buf[1];
1006 pal_ptr->blue = buf[2];
1009 for (i = 0; i < num; i++)
1013 png_crc_read(png_ptr, buf, 3);
1014 /* Don't depend upon png_color being any order */
1015 palette[i].red = buf[0];
1016 palette[i].green = buf[1];
1017 palette[i].blue = buf[2];
1021 /* If we actually need the PLTE chunk (ie for a paletted image), we do
1022 * whatever the normal CRC configuration tells us. However, if we
1023 * have an RGB image, the PLTE can be considered ancillary, so
1024 * we will act as though it is.
1026 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
1027 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1030 png_crc_finish(png_ptr, (png_uint_32) (length - (unsigned int)num * 3));
1033 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
1034 else if (png_crc_error(png_ptr) != 0) /* Only if we have a CRC error */
1036 /* If we don't want to use the data from an ancillary chunk,
1037 * we have two options: an error abort, or a warning and we
1038 * ignore the data in this chunk (which should be OK, since
1039 * it's considered ancillary for a RGB or RGBA image).
1041 * IMPLEMENTATION NOTE: this is only here because png_crc_finish uses the
1042 * chunk type to determine whether to check the ancillary or the critical
1045 if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_USE) == 0)
1047 if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) != 0)
1051 png_chunk_error(png_ptr, "CRC error");
1054 /* Otherwise, we (optionally) emit a warning and use the chunk. */
1055 else if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) == 0)
1056 png_chunk_warning(png_ptr, "CRC error");
1060 /* TODO: png_set_PLTE has the side effect of setting png_ptr->palette to its
1061 * own copy of the palette. This has the side effect that when png_start_row
1062 * is called (this happens after any call to png_read_update_info) the
1063 * info_ptr palette gets changed. This is extremely unexpected and
1066 * Fix this by not sharing the palette in this way.
1068 png_set_PLTE(png_ptr, info_ptr, palette, num);
1070 /* The three chunks, bKGD, hIST and tRNS *must* appear after PLTE and before
1071 * IDAT. Prior to 1.6.0 this was not checked; instead the code merely
1072 * checked the apparent validity of a tRNS chunk inserted before PLTE on a
1073 * palette PNG. 1.6.0 attempts to rigorously follow the standard and
1074 * therefore does a benign error if the erroneous condition is detected *and*
1075 * cancels the tRNS if the benign error returns. The alternative is to
1076 * amend the standard since it would be rather hypocritical of the standards
1077 * maintainers to ignore it.
1079 #ifdef PNG_READ_tRNS_SUPPORTED
1080 if (png_ptr->num_trans > 0 ||
1081 (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0))
1083 /* Cancel this because otherwise it would be used if the transforms
1084 * require it. Don't cancel the 'valid' flag because this would prevent
1085 * detection of duplicate chunks.
1087 png_ptr->num_trans = 0;
1089 if (info_ptr != NULL)
1090 info_ptr->num_trans = 0;
1092 png_chunk_benign_error(png_ptr, "tRNS must be after");
1096 #ifdef PNG_READ_hIST_SUPPORTED
1097 if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0)
1098 png_chunk_benign_error(png_ptr, "hIST must be after");
1101 #ifdef PNG_READ_bKGD_SUPPORTED
1102 if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0)
1103 png_chunk_benign_error(png_ptr, "bKGD must be after");
1108 png_handle_IEND(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1110 png_debug(1, "in png_handle_IEND");
1112 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0 ||
1113 (png_ptr->mode & PNG_HAVE_IDAT) == 0)
1114 png_chunk_error(png_ptr, "out of place");
1116 png_ptr->mode |= (PNG_AFTER_IDAT | PNG_HAVE_IEND);
1118 png_crc_finish(png_ptr, length);
1121 png_chunk_benign_error(png_ptr, "invalid");
1123 PNG_UNUSED(info_ptr)
1126 #ifdef PNG_READ_gAMA_SUPPORTED
1128 png_handle_gAMA(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1130 png_fixed_point igamma;
1133 png_debug(1, "in png_handle_gAMA");
1135 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1136 png_chunk_error(png_ptr, "missing IHDR");
1138 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
1140 png_crc_finish(png_ptr, length);
1141 png_chunk_benign_error(png_ptr, "out of place");
1147 png_crc_finish(png_ptr, length);
1148 png_chunk_benign_error(png_ptr, "invalid");
1152 png_crc_read(png_ptr, buf, 4);
1154 if (png_crc_finish(png_ptr, 0) != 0)
1157 igamma = png_get_fixed_point(NULL, buf);
1159 png_colorspace_set_gamma(png_ptr, &png_ptr->colorspace, igamma);
1160 png_colorspace_sync(png_ptr, info_ptr);
1164 #ifdef PNG_READ_sBIT_SUPPORTED
1166 png_handle_sBIT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1168 unsigned int truelen, i;
1169 png_byte sample_depth;
1172 png_debug(1, "in png_handle_sBIT");
1174 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1175 png_chunk_error(png_ptr, "missing IHDR");
1177 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
1179 png_crc_finish(png_ptr, length);
1180 png_chunk_benign_error(png_ptr, "out of place");
1184 if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT) != 0)
1186 png_crc_finish(png_ptr, length);
1187 png_chunk_benign_error(png_ptr, "duplicate");
1191 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1199 truelen = png_ptr->channels;
1200 sample_depth = png_ptr->bit_depth;
1203 if (length != truelen || length > 4)
1205 png_chunk_benign_error(png_ptr, "invalid");
1206 png_crc_finish(png_ptr, length);
1210 buf[0] = buf[1] = buf[2] = buf[3] = sample_depth;
1211 png_crc_read(png_ptr, buf, truelen);
1213 if (png_crc_finish(png_ptr, 0) != 0)
1216 for (i=0; i<truelen; ++i)
1218 if (buf[i] == 0 || buf[i] > sample_depth)
1220 png_chunk_benign_error(png_ptr, "invalid");
1225 if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
1227 png_ptr->sig_bit.red = buf[0];
1228 png_ptr->sig_bit.green = buf[1];
1229 png_ptr->sig_bit.blue = buf[2];
1230 png_ptr->sig_bit.alpha = buf[3];
1235 png_ptr->sig_bit.gray = buf[0];
1236 png_ptr->sig_bit.red = buf[0];
1237 png_ptr->sig_bit.green = buf[0];
1238 png_ptr->sig_bit.blue = buf[0];
1239 png_ptr->sig_bit.alpha = buf[1];
1242 png_set_sBIT(png_ptr, info_ptr, &(png_ptr->sig_bit));
1246 #ifdef PNG_READ_cHRM_SUPPORTED
1248 png_handle_cHRM(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1253 png_debug(1, "in png_handle_cHRM");
1255 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1256 png_chunk_error(png_ptr, "missing IHDR");
1258 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
1260 png_crc_finish(png_ptr, length);
1261 png_chunk_benign_error(png_ptr, "out of place");
1267 png_crc_finish(png_ptr, length);
1268 png_chunk_benign_error(png_ptr, "invalid");
1272 png_crc_read(png_ptr, buf, 32);
1274 if (png_crc_finish(png_ptr, 0) != 0)
1277 xy.whitex = png_get_fixed_point(NULL, buf);
1278 xy.whitey = png_get_fixed_point(NULL, buf + 4);
1279 xy.redx = png_get_fixed_point(NULL, buf + 8);
1280 xy.redy = png_get_fixed_point(NULL, buf + 12);
1281 xy.greenx = png_get_fixed_point(NULL, buf + 16);
1282 xy.greeny = png_get_fixed_point(NULL, buf + 20);
1283 xy.bluex = png_get_fixed_point(NULL, buf + 24);
1284 xy.bluey = png_get_fixed_point(NULL, buf + 28);
1286 if (xy.whitex == PNG_FIXED_ERROR ||
1287 xy.whitey == PNG_FIXED_ERROR ||
1288 xy.redx == PNG_FIXED_ERROR ||
1289 xy.redy == PNG_FIXED_ERROR ||
1290 xy.greenx == PNG_FIXED_ERROR ||
1291 xy.greeny == PNG_FIXED_ERROR ||
1292 xy.bluex == PNG_FIXED_ERROR ||
1293 xy.bluey == PNG_FIXED_ERROR)
1295 png_chunk_benign_error(png_ptr, "invalid values");
1299 /* If a colorspace error has already been output skip this chunk */
1300 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
1303 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) != 0)
1305 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
1306 png_colorspace_sync(png_ptr, info_ptr);
1307 png_chunk_benign_error(png_ptr, "duplicate");
1311 png_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;
1312 (void)png_colorspace_set_chromaticities(png_ptr, &png_ptr->colorspace, &xy,
1313 1/*prefer cHRM values*/);
1314 png_colorspace_sync(png_ptr, info_ptr);
1318 #ifdef PNG_READ_sRGB_SUPPORTED
1320 png_handle_sRGB(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1324 png_debug(1, "in png_handle_sRGB");
1326 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1327 png_chunk_error(png_ptr, "missing IHDR");
1329 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
1331 png_crc_finish(png_ptr, length);
1332 png_chunk_benign_error(png_ptr, "out of place");
1338 png_crc_finish(png_ptr, length);
1339 png_chunk_benign_error(png_ptr, "invalid");
1343 png_crc_read(png_ptr, &intent, 1);
1345 if (png_crc_finish(png_ptr, 0) != 0)
1348 /* If a colorspace error has already been output skip this chunk */
1349 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
1352 /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
1355 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) != 0)
1357 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
1358 png_colorspace_sync(png_ptr, info_ptr);
1359 png_chunk_benign_error(png_ptr, "too many profiles");
1363 (void)png_colorspace_set_sRGB(png_ptr, &png_ptr->colorspace, intent);
1364 png_colorspace_sync(png_ptr, info_ptr);
1366 #endif /* READ_sRGB */
1368 #ifdef PNG_READ_iCCP_SUPPORTED
1370 png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1371 /* Note: this does not properly handle profiles that are > 64K under DOS */
1373 png_const_charp errmsg = NULL; /* error message output, or no error */
1374 int finished = 0; /* crc checked */
1376 png_debug(1, "in png_handle_iCCP");
1378 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1379 png_chunk_error(png_ptr, "missing IHDR");
1381 else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
1383 png_crc_finish(png_ptr, length);
1384 png_chunk_benign_error(png_ptr, "out of place");
1388 /* Consistent with all the above colorspace handling an obviously *invalid*
1389 * chunk is just ignored, so does not invalidate the color space. An
1390 * alternative is to set the 'invalid' flags at the start of this routine
1391 * and only clear them in they were not set before and all the tests pass.
1394 /* The keyword must be at least one character and there is a
1395 * terminator (0) byte and the compression method byte, and the
1396 * 'zlib' datastream is at least 11 bytes.
1400 png_crc_finish(png_ptr, length);
1401 png_chunk_benign_error(png_ptr, "too short");
1405 /* If a colorspace error has already been output skip this chunk */
1406 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
1408 png_crc_finish(png_ptr, length);
1412 /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
1415 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) == 0)
1417 uInt read_length, keyword_length;
1420 /* Find the keyword; the keyword plus separator and compression method
1421 * bytes can be at most 81 characters long.
1423 read_length = 81; /* maximum */
1424 if (read_length > length)
1425 read_length = (uInt)length;
1427 png_crc_read(png_ptr, (png_bytep)keyword, read_length);
1428 length -= read_length;
1430 /* The minimum 'zlib' stream is assumed to be just the 2 byte header,
1431 * 5 bytes minimum 'deflate' stream, and the 4 byte checksum.
1435 png_crc_finish(png_ptr, length);
1436 png_chunk_benign_error(png_ptr, "too short");
1441 while (keyword_length < 80 && keyword_length < read_length &&
1442 keyword[keyword_length] != 0)
1445 /* TODO: make the keyword checking common */
1446 if (keyword_length >= 1 && keyword_length <= 79)
1448 /* We only understand '0' compression - deflate - so if we get a
1449 * different value we can't safely decode the chunk.
1451 if (keyword_length+1 < read_length &&
1452 keyword[keyword_length+1] == PNG_COMPRESSION_TYPE_BASE)
1454 read_length -= keyword_length+2;
1456 if (png_inflate_claim(png_ptr, png_iCCP) == Z_OK)
1458 Byte profile_header[132]={0};
1459 Byte local_buffer[PNG_INFLATE_BUF_SIZE];
1460 png_alloc_size_t size = (sizeof profile_header);
1462 png_ptr->zstream.next_in = (Bytef*)keyword + (keyword_length+2);
1463 png_ptr->zstream.avail_in = read_length;
1464 (void)png_inflate_read(png_ptr, local_buffer,
1465 (sizeof local_buffer), &length, profile_header, &size,
1466 0/*finish: don't, because the output is too small*/);
1470 /* We have the ICC profile header; do the basic header checks.
1472 png_uint_32 profile_length = png_get_uint_32(profile_header);
1474 if (png_icc_check_length(png_ptr, &png_ptr->colorspace,
1475 keyword, profile_length) != 0)
1477 /* The length is apparently ok, so we can check the 132
1480 if (png_icc_check_header(png_ptr, &png_ptr->colorspace,
1481 keyword, profile_length, profile_header,
1482 png_ptr->color_type) != 0)
1484 /* Now read the tag table; a variable size buffer is
1485 * needed at this point, allocate one for the whole
1486 * profile. The header check has already validated
1487 * that none of this stuff will overflow.
1489 png_uint_32 tag_count =
1490 png_get_uint_32(profile_header + 128);
1491 png_bytep profile = png_read_buffer(png_ptr,
1492 profile_length, 2/*silent*/);
1494 if (profile != NULL)
1496 memcpy(profile, profile_header,
1497 (sizeof profile_header));
1499 size = 12 * tag_count;
1501 (void)png_inflate_read(png_ptr, local_buffer,
1502 (sizeof local_buffer), &length,
1503 profile + (sizeof profile_header), &size, 0);
1505 /* Still expect a buffer error because we expect
1506 * there to be some tag data!
1510 if (png_icc_check_tag_table(png_ptr,
1511 &png_ptr->colorspace, keyword, profile_length,
1514 /* The profile has been validated for basic
1515 * security issues, so read the whole thing in.
1517 size = profile_length - (sizeof profile_header)
1520 (void)png_inflate_read(png_ptr, local_buffer,
1521 (sizeof local_buffer), &length,
1522 profile + (sizeof profile_header) +
1523 12 * tag_count, &size, 1/*finish*/);
1525 if (length > 0 && !(png_ptr->flags &
1526 PNG_FLAG_BENIGN_ERRORS_WARN))
1527 errmsg = "extra compressed data";
1529 /* But otherwise allow extra data: */
1534 /* This can be handled completely, so
1537 png_chunk_warning(png_ptr,
1538 "extra compressed data");
1541 png_crc_finish(png_ptr, length);
1544 # if defined(PNG_sRGB_SUPPORTED) && PNG_sRGB_PROFILE_CHECKS >= 0
1545 /* Check for a match against sRGB */
1546 png_icc_set_sRGB(png_ptr,
1547 &png_ptr->colorspace, profile,
1548 png_ptr->zstream.adler);
1551 /* Steal the profile for info_ptr. */
1552 if (info_ptr != NULL)
1554 png_free_data(png_ptr, info_ptr,
1557 info_ptr->iccp_name = png_voidcast(char*,
1558 png_malloc_base(png_ptr,
1560 if (info_ptr->iccp_name != NULL)
1562 memcpy(info_ptr->iccp_name, keyword,
1564 info_ptr->iccp_proflen =
1566 info_ptr->iccp_profile = profile;
1567 png_ptr->read_buffer = NULL; /*steal*/
1568 info_ptr->free_me |= PNG_FREE_ICCP;
1569 info_ptr->valid |= PNG_INFO_iCCP;
1574 png_ptr->colorspace.flags |=
1575 PNG_COLORSPACE_INVALID;
1576 errmsg = "out of memory";
1580 /* else the profile remains in the read
1581 * buffer which gets reused for subsequent
1585 if (info_ptr != NULL)
1586 png_colorspace_sync(png_ptr, info_ptr);
1590 png_ptr->zowner = 0;
1595 errmsg = png_ptr->zstream.msg;
1597 /* else png_icc_check_tag_table output an error */
1599 else /* profile truncated */
1600 errmsg = png_ptr->zstream.msg;
1604 errmsg = "out of memory";
1607 /* else png_icc_check_header output an error */
1610 /* else png_icc_check_length output an error */
1613 else /* profile truncated */
1614 errmsg = png_ptr->zstream.msg;
1616 /* Release the stream */
1617 png_ptr->zowner = 0;
1620 else /* png_inflate_claim failed */
1621 errmsg = png_ptr->zstream.msg;
1625 errmsg = "bad compression method"; /* or missing */
1629 errmsg = "bad keyword";
1633 errmsg = "too many profiles";
1635 /* Failure: the reason is in 'errmsg' */
1637 png_crc_finish(png_ptr, length);
1639 png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
1640 png_colorspace_sync(png_ptr, info_ptr);
1641 if (errmsg != NULL) /* else already output */
1642 png_chunk_benign_error(png_ptr, errmsg);
1644 #endif /* READ_iCCP */
1646 #ifdef PNG_READ_sPLT_SUPPORTED
1648 png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1649 /* Note: this does not properly handle chunks that are > 64K under DOS */
1651 png_bytep entry_start, buffer;
1652 png_sPLT_t new_palette;
1654 png_uint_32 data_length;
1656 png_uint_32 skip = 0;
1660 png_debug(1, "in png_handle_sPLT");
1662 #ifdef PNG_USER_LIMITS_SUPPORTED
1663 if (png_ptr->user_chunk_cache_max != 0)
1665 if (png_ptr->user_chunk_cache_max == 1)
1667 png_crc_finish(png_ptr, length);
1671 if (--png_ptr->user_chunk_cache_max == 1)
1673 png_warning(png_ptr, "No space in chunk cache for sPLT");
1674 png_crc_finish(png_ptr, length);
1680 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1681 png_chunk_error(png_ptr, "missing IHDR");
1683 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
1685 png_crc_finish(png_ptr, length);
1686 png_chunk_benign_error(png_ptr, "out of place");
1690 #ifdef PNG_MAX_MALLOC_64K
1691 if (length > 65535U)
1693 png_crc_finish(png_ptr, length);
1694 png_chunk_benign_error(png_ptr, "too large to fit in memory");
1699 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
1702 png_crc_finish(png_ptr, length);
1703 png_chunk_benign_error(png_ptr, "out of memory");
1708 /* WARNING: this may break if size_t is less than 32 bits; it is assumed
1709 * that the PNG_MAX_MALLOC_64K test is enabled in this case, but this is a
1710 * potential breakage point if the types in pngconf.h aren't exactly right.
1712 png_crc_read(png_ptr, buffer, length);
1714 if (png_crc_finish(png_ptr, skip) != 0)
1719 for (entry_start = buffer; *entry_start; entry_start++)
1720 /* Empty loop to find end of name */ ;
1724 /* A sample depth should follow the separator, and we should be on it */
1725 if (length < 2U || entry_start > buffer + (length - 2U))
1727 png_warning(png_ptr, "malformed sPLT chunk");
1731 new_palette.depth = *entry_start++;
1732 entry_size = (new_palette.depth == 8 ? 6 : 10);
1733 /* This must fit in a png_uint_32 because it is derived from the original
1734 * chunk data length.
1736 data_length = length - (png_uint_32)(entry_start - buffer);
1738 /* Integrity-check the data length */
1739 if ((data_length % (unsigned int)entry_size) != 0)
1741 png_warning(png_ptr, "sPLT chunk has bad length");
1745 dl = (png_uint_32)(data_length / (unsigned int)entry_size);
1746 max_dl = PNG_SIZE_MAX / (sizeof (png_sPLT_entry));
1750 png_warning(png_ptr, "sPLT chunk too long");
1754 new_palette.nentries = (png_int_32)(data_length / (unsigned int)entry_size);
1756 new_palette.entries = (png_sPLT_entryp)png_malloc_warn(png_ptr,
1757 (png_alloc_size_t) new_palette.nentries * (sizeof (png_sPLT_entry)));
1759 if (new_palette.entries == NULL)
1761 png_warning(png_ptr, "sPLT chunk requires too much memory");
1765 #ifdef PNG_POINTER_INDEXING_SUPPORTED
1766 for (i = 0; i < new_palette.nentries; i++)
1768 pp = new_palette.entries + i;
1770 if (new_palette.depth == 8)
1772 pp->red = *entry_start++;
1773 pp->green = *entry_start++;
1774 pp->blue = *entry_start++;
1775 pp->alpha = *entry_start++;
1780 pp->red = png_get_uint_16(entry_start); entry_start += 2;
1781 pp->green = png_get_uint_16(entry_start); entry_start += 2;
1782 pp->blue = png_get_uint_16(entry_start); entry_start += 2;
1783 pp->alpha = png_get_uint_16(entry_start); entry_start += 2;
1786 pp->frequency = png_get_uint_16(entry_start); entry_start += 2;
1789 pp = new_palette.entries;
1791 for (i = 0; i < new_palette.nentries; i++)
1794 if (new_palette.depth == 8)
1796 pp[i].red = *entry_start++;
1797 pp[i].green = *entry_start++;
1798 pp[i].blue = *entry_start++;
1799 pp[i].alpha = *entry_start++;
1804 pp[i].red = png_get_uint_16(entry_start); entry_start += 2;
1805 pp[i].green = png_get_uint_16(entry_start); entry_start += 2;
1806 pp[i].blue = png_get_uint_16(entry_start); entry_start += 2;
1807 pp[i].alpha = png_get_uint_16(entry_start); entry_start += 2;
1810 pp[i].frequency = png_get_uint_16(entry_start); entry_start += 2;
1814 /* Discard all chunk data except the name and stash that */
1815 new_palette.name = (png_charp)buffer;
1817 png_set_sPLT(png_ptr, info_ptr, &new_palette, 1);
1819 png_free(png_ptr, new_palette.entries);
1821 #endif /* READ_sPLT */
1823 #ifdef PNG_READ_tRNS_SUPPORTED
1825 png_handle_tRNS(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1827 png_byte readbuf[PNG_MAX_PALETTE_LENGTH];
1829 png_debug(1, "in png_handle_tRNS");
1831 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1832 png_chunk_error(png_ptr, "missing IHDR");
1834 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
1836 png_crc_finish(png_ptr, length);
1837 png_chunk_benign_error(png_ptr, "out of place");
1841 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0)
1843 png_crc_finish(png_ptr, length);
1844 png_chunk_benign_error(png_ptr, "duplicate");
1848 if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
1854 png_crc_finish(png_ptr, length);
1855 png_chunk_benign_error(png_ptr, "invalid");
1859 png_crc_read(png_ptr, buf, 2);
1860 png_ptr->num_trans = 1;
1861 png_ptr->trans_color.gray = png_get_uint_16(buf);
1864 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
1870 png_crc_finish(png_ptr, length);
1871 png_chunk_benign_error(png_ptr, "invalid");
1875 png_crc_read(png_ptr, buf, length);
1876 png_ptr->num_trans = 1;
1877 png_ptr->trans_color.red = png_get_uint_16(buf);
1878 png_ptr->trans_color.green = png_get_uint_16(buf + 2);
1879 png_ptr->trans_color.blue = png_get_uint_16(buf + 4);
1882 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1884 if ((png_ptr->mode & PNG_HAVE_PLTE) == 0)
1886 /* TODO: is this actually an error in the ISO spec? */
1887 png_crc_finish(png_ptr, length);
1888 png_chunk_benign_error(png_ptr, "out of place");
1892 if (length > (unsigned int) png_ptr->num_palette ||
1893 length > (unsigned int) PNG_MAX_PALETTE_LENGTH ||
1896 png_crc_finish(png_ptr, length);
1897 png_chunk_benign_error(png_ptr, "invalid");
1901 png_crc_read(png_ptr, readbuf, length);
1902 png_ptr->num_trans = (png_uint_16)length;
1907 png_crc_finish(png_ptr, length);
1908 png_chunk_benign_error(png_ptr, "invalid with alpha channel");
1912 if (png_crc_finish(png_ptr, 0) != 0)
1914 png_ptr->num_trans = 0;
1918 /* TODO: this is a horrible side effect in the palette case because the
1919 * png_struct ends up with a pointer to the tRNS buffer owned by the
1920 * png_info. Fix this.
1922 png_set_tRNS(png_ptr, info_ptr, readbuf, png_ptr->num_trans,
1923 &(png_ptr->trans_color));
1927 #ifdef PNG_READ_bKGD_SUPPORTED
1929 png_handle_bKGD(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
1931 unsigned int truelen;
1933 png_color_16 background;
1935 png_debug(1, "in png_handle_bKGD");
1937 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
1938 png_chunk_error(png_ptr, "missing IHDR");
1940 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 ||
1941 (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
1942 (png_ptr->mode & PNG_HAVE_PLTE) == 0))
1944 png_crc_finish(png_ptr, length);
1945 png_chunk_benign_error(png_ptr, "out of place");
1949 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0)
1951 png_crc_finish(png_ptr, length);
1952 png_chunk_benign_error(png_ptr, "duplicate");
1956 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1959 else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
1965 if (length != truelen)
1967 png_crc_finish(png_ptr, length);
1968 png_chunk_benign_error(png_ptr, "invalid");
1972 png_crc_read(png_ptr, buf, truelen);
1974 if (png_crc_finish(png_ptr, 0) != 0)
1977 /* We convert the index value into RGB components so that we can allow
1978 * arbitrary RGB values for background when we have transparency, and
1979 * so it is easy to determine the RGB values of the background color
1980 * from the info_ptr struct.
1982 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1984 background.index = buf[0];
1986 if (info_ptr != NULL && info_ptr->num_palette != 0)
1988 if (buf[0] >= info_ptr->num_palette)
1990 png_chunk_benign_error(png_ptr, "invalid index");
1994 background.red = (png_uint_16)png_ptr->palette[buf[0]].red;
1995 background.green = (png_uint_16)png_ptr->palette[buf[0]].green;
1996 background.blue = (png_uint_16)png_ptr->palette[buf[0]].blue;
2000 background.red = background.green = background.blue = 0;
2002 background.gray = 0;
2005 else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0) /* GRAY */
2007 if (png_ptr->bit_depth <= 8)
2009 if (buf[0] != 0 || buf[1] >= (unsigned int)(1 << png_ptr->bit_depth))
2011 png_chunk_benign_error(png_ptr, "invalid gray level");
2016 background.index = 0;
2020 background.gray = png_get_uint_16(buf);
2025 if (png_ptr->bit_depth <= 8)
2027 if (buf[0] != 0 || buf[2] != 0 || buf[4] != 0)
2029 png_chunk_benign_error(png_ptr, "invalid color");
2034 background.index = 0;
2035 background.red = png_get_uint_16(buf);
2036 background.green = png_get_uint_16(buf + 2);
2037 background.blue = png_get_uint_16(buf + 4);
2038 background.gray = 0;
2041 png_set_bKGD(png_ptr, info_ptr, &background);
2045 #ifdef PNG_READ_eXIf_SUPPORTED
2047 png_handle_eXIf(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2051 png_debug(1, "in png_handle_eXIf");
2053 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2054 png_chunk_error(png_ptr, "missing IHDR");
2058 png_crc_finish(png_ptr, length);
2059 png_chunk_benign_error(png_ptr, "too short");
2063 else if (info_ptr == NULL || (info_ptr->valid & PNG_INFO_eXIf) != 0)
2065 png_crc_finish(png_ptr, length);
2066 png_chunk_benign_error(png_ptr, "duplicate");
2070 info_ptr->free_me |= PNG_FREE_EXIF;
2072 info_ptr->eXIf_buf = png_voidcast(png_bytep,
2073 png_malloc_warn(png_ptr, length));
2075 if (info_ptr->eXIf_buf == NULL)
2077 png_crc_finish(png_ptr, length);
2078 png_chunk_benign_error(png_ptr, "out of memory");
2082 for (i = 0; i < length; i++)
2085 png_crc_read(png_ptr, buf, 1);
2086 info_ptr->eXIf_buf[i] = buf[0];
2087 if (i == 1 && buf[0] != 'M' && buf[0] != 'I'
2088 && info_ptr->eXIf_buf[0] != buf[0])
2090 png_crc_finish(png_ptr, length);
2091 png_chunk_benign_error(png_ptr, "incorrect byte-order specifier");
2092 png_free(png_ptr, info_ptr->eXIf_buf);
2093 info_ptr->eXIf_buf = NULL;
2098 if (png_crc_finish(png_ptr, 0) != 0)
2101 png_set_eXIf_1(png_ptr, info_ptr, length, info_ptr->eXIf_buf);
2103 png_free(png_ptr, info_ptr->eXIf_buf);
2104 info_ptr->eXIf_buf = NULL;
2108 #ifdef PNG_READ_hIST_SUPPORTED
2110 png_handle_hIST(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2112 unsigned int num, i;
2113 png_uint_16 readbuf[PNG_MAX_PALETTE_LENGTH];
2115 png_debug(1, "in png_handle_hIST");
2117 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2118 png_chunk_error(png_ptr, "missing IHDR");
2120 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 ||
2121 (png_ptr->mode & PNG_HAVE_PLTE) == 0)
2123 png_crc_finish(png_ptr, length);
2124 png_chunk_benign_error(png_ptr, "out of place");
2128 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0)
2130 png_crc_finish(png_ptr, length);
2131 png_chunk_benign_error(png_ptr, "duplicate");
2137 if (num != (unsigned int) png_ptr->num_palette ||
2138 num > (unsigned int) PNG_MAX_PALETTE_LENGTH)
2140 png_crc_finish(png_ptr, length);
2141 png_chunk_benign_error(png_ptr, "invalid");
2145 for (i = 0; i < num; i++)
2149 png_crc_read(png_ptr, buf, 2);
2150 readbuf[i] = png_get_uint_16(buf);
2153 if (png_crc_finish(png_ptr, 0) != 0)
2156 png_set_hIST(png_ptr, info_ptr, readbuf);
2160 #ifdef PNG_READ_pHYs_SUPPORTED
2162 png_handle_pHYs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2165 png_uint_32 res_x, res_y;
2168 png_debug(1, "in png_handle_pHYs");
2170 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2171 png_chunk_error(png_ptr, "missing IHDR");
2173 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2175 png_crc_finish(png_ptr, length);
2176 png_chunk_benign_error(png_ptr, "out of place");
2180 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs) != 0)
2182 png_crc_finish(png_ptr, length);
2183 png_chunk_benign_error(png_ptr, "duplicate");
2189 png_crc_finish(png_ptr, length);
2190 png_chunk_benign_error(png_ptr, "invalid");
2194 png_crc_read(png_ptr, buf, 9);
2196 if (png_crc_finish(png_ptr, 0) != 0)
2199 res_x = png_get_uint_32(buf);
2200 res_y = png_get_uint_32(buf + 4);
2202 png_set_pHYs(png_ptr, info_ptr, res_x, res_y, unit_type);
2206 #ifdef PNG_READ_oFFs_SUPPORTED
2208 png_handle_oFFs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2211 png_int_32 offset_x, offset_y;
2214 png_debug(1, "in png_handle_oFFs");
2216 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2217 png_chunk_error(png_ptr, "missing IHDR");
2219 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2221 png_crc_finish(png_ptr, length);
2222 png_chunk_benign_error(png_ptr, "out of place");
2226 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs) != 0)
2228 png_crc_finish(png_ptr, length);
2229 png_chunk_benign_error(png_ptr, "duplicate");
2235 png_crc_finish(png_ptr, length);
2236 png_chunk_benign_error(png_ptr, "invalid");
2240 png_crc_read(png_ptr, buf, 9);
2242 if (png_crc_finish(png_ptr, 0) != 0)
2245 offset_x = png_get_int_32(buf);
2246 offset_y = png_get_int_32(buf + 4);
2248 png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y, unit_type);
2252 #ifdef PNG_READ_pCAL_SUPPORTED
2253 /* Read the pCAL chunk (described in the PNG Extensions document) */
2255 png_handle_pCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2258 png_byte type, nparams;
2259 png_bytep buffer, buf, units, endptr;
2263 png_debug(1, "in png_handle_pCAL");
2265 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2266 png_chunk_error(png_ptr, "missing IHDR");
2268 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2270 png_crc_finish(png_ptr, length);
2271 png_chunk_benign_error(png_ptr, "out of place");
2275 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL) != 0)
2277 png_crc_finish(png_ptr, length);
2278 png_chunk_benign_error(png_ptr, "duplicate");
2282 png_debug1(2, "Allocating and reading pCAL chunk data (%u bytes)",
2285 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
2289 png_crc_finish(png_ptr, length);
2290 png_chunk_benign_error(png_ptr, "out of memory");
2294 png_crc_read(png_ptr, buffer, length);
2296 if (png_crc_finish(png_ptr, 0) != 0)
2299 buffer[length] = 0; /* Null terminate the last string */
2301 png_debug(3, "Finding end of pCAL purpose string");
2302 for (buf = buffer; *buf; buf++)
2305 endptr = buffer + length;
2307 /* We need to have at least 12 bytes after the purpose string
2308 * in order to get the parameter information.
2310 if (endptr - buf <= 12)
2312 png_chunk_benign_error(png_ptr, "invalid");
2316 png_debug(3, "Reading pCAL X0, X1, type, nparams, and units");
2317 X0 = png_get_int_32((png_bytep)buf+1);
2318 X1 = png_get_int_32((png_bytep)buf+5);
2323 png_debug(3, "Checking pCAL equation type and number of parameters");
2324 /* Check that we have the right number of parameters for known
2327 if ((type == PNG_EQUATION_LINEAR && nparams != 2) ||
2328 (type == PNG_EQUATION_BASE_E && nparams != 3) ||
2329 (type == PNG_EQUATION_ARBITRARY && nparams != 3) ||
2330 (type == PNG_EQUATION_HYPERBOLIC && nparams != 4))
2332 png_chunk_benign_error(png_ptr, "invalid parameter count");
2336 else if (type >= PNG_EQUATION_LAST)
2338 png_chunk_benign_error(png_ptr, "unrecognized equation type");
2341 for (buf = units; *buf; buf++)
2342 /* Empty loop to move past the units string. */ ;
2344 png_debug(3, "Allocating pCAL parameters array");
2346 params = png_voidcast(png_charpp, png_malloc_warn(png_ptr,
2347 nparams * (sizeof (png_charp))));
2351 png_chunk_benign_error(png_ptr, "out of memory");
2355 /* Get pointers to the start of each parameter string. */
2356 for (i = 0; i < nparams; i++)
2358 buf++; /* Skip the null string terminator from previous parameter. */
2360 png_debug1(3, "Reading pCAL parameter %d", i);
2362 for (params[i] = (png_charp)buf; buf <= endptr && *buf != 0; buf++)
2363 /* Empty loop to move past each parameter string */ ;
2365 /* Make sure we haven't run out of data yet */
2368 png_free(png_ptr, params);
2369 png_chunk_benign_error(png_ptr, "invalid data");
2374 png_set_pCAL(png_ptr, info_ptr, (png_charp)buffer, X0, X1, type, nparams,
2375 (png_charp)units, params);
2377 png_free(png_ptr, params);
2381 #ifdef PNG_READ_sCAL_SUPPORTED
2382 /* Read the sCAL chunk */
2384 png_handle_sCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2390 png_debug(1, "in png_handle_sCAL");
2392 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2393 png_chunk_error(png_ptr, "missing IHDR");
2395 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2397 png_crc_finish(png_ptr, length);
2398 png_chunk_benign_error(png_ptr, "out of place");
2402 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sCAL) != 0)
2404 png_crc_finish(png_ptr, length);
2405 png_chunk_benign_error(png_ptr, "duplicate");
2409 /* Need unit type, width, \0, height: minimum 4 bytes */
2410 else if (length < 4)
2412 png_crc_finish(png_ptr, length);
2413 png_chunk_benign_error(png_ptr, "invalid");
2417 png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)",
2420 buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
2424 png_chunk_benign_error(png_ptr, "out of memory");
2425 png_crc_finish(png_ptr, length);
2429 png_crc_read(png_ptr, buffer, length);
2430 buffer[length] = 0; /* Null terminate the last string */
2432 if (png_crc_finish(png_ptr, 0) != 0)
2435 /* Validate the unit. */
2436 if (buffer[0] != 1 && buffer[0] != 2)
2438 png_chunk_benign_error(png_ptr, "invalid unit");
2442 /* Validate the ASCII numbers, need two ASCII numbers separated by
2443 * a '\0' and they need to fit exactly in the chunk data.
2448 if (png_check_fp_number((png_const_charp)buffer, length, &state, &i) == 0 ||
2449 i >= length || buffer[i++] != 0)
2450 png_chunk_benign_error(png_ptr, "bad width format");
2452 else if (PNG_FP_IS_POSITIVE(state) == 0)
2453 png_chunk_benign_error(png_ptr, "non-positive width");
2460 if (png_check_fp_number((png_const_charp)buffer, length,
2461 &state, &i) == 0 || i != length)
2462 png_chunk_benign_error(png_ptr, "bad height format");
2464 else if (PNG_FP_IS_POSITIVE(state) == 0)
2465 png_chunk_benign_error(png_ptr, "non-positive height");
2468 /* This is the (only) success case. */
2469 png_set_sCAL_s(png_ptr, info_ptr, buffer[0],
2470 (png_charp)buffer+1, (png_charp)buffer+heighti);
2475 #ifdef PNG_READ_tIME_SUPPORTED
2477 png_handle_tIME(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2482 png_debug(1, "in png_handle_tIME");
2484 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2485 png_chunk_error(png_ptr, "missing IHDR");
2487 else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME) != 0)
2489 png_crc_finish(png_ptr, length);
2490 png_chunk_benign_error(png_ptr, "duplicate");
2494 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2495 png_ptr->mode |= PNG_AFTER_IDAT;
2499 png_crc_finish(png_ptr, length);
2500 png_chunk_benign_error(png_ptr, "invalid");
2504 png_crc_read(png_ptr, buf, 7);
2506 if (png_crc_finish(png_ptr, 0) != 0)
2509 mod_time.second = buf[6];
2510 mod_time.minute = buf[5];
2511 mod_time.hour = buf[4];
2512 mod_time.day = buf[3];
2513 mod_time.month = buf[2];
2514 mod_time.year = png_get_uint_16(buf);
2516 png_set_tIME(png_ptr, info_ptr, &mod_time);
2520 #ifdef PNG_READ_tEXt_SUPPORTED
2521 /* Note: this does not properly handle chunks that are > 64K under DOS */
2523 png_handle_tEXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2529 png_uint_32 skip = 0;
2531 png_debug(1, "in png_handle_tEXt");
2533 #ifdef PNG_USER_LIMITS_SUPPORTED
2534 if (png_ptr->user_chunk_cache_max != 0)
2536 if (png_ptr->user_chunk_cache_max == 1)
2538 png_crc_finish(png_ptr, length);
2542 if (--png_ptr->user_chunk_cache_max == 1)
2544 png_crc_finish(png_ptr, length);
2545 png_chunk_benign_error(png_ptr, "no space in chunk cache");
2551 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2552 png_chunk_error(png_ptr, "missing IHDR");
2554 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2555 png_ptr->mode |= PNG_AFTER_IDAT;
2557 #ifdef PNG_MAX_MALLOC_64K
2558 if (length > 65535U)
2560 png_crc_finish(png_ptr, length);
2561 png_chunk_benign_error(png_ptr, "too large to fit in memory");
2566 buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/);
2570 png_chunk_benign_error(png_ptr, "out of memory");
2574 png_crc_read(png_ptr, buffer, length);
2576 if (png_crc_finish(png_ptr, skip) != 0)
2579 key = (png_charp)buffer;
2582 for (text = key; *text; text++)
2583 /* Empty loop to find end of key */ ;
2585 if (text != key + length)
2588 text_info.compression = PNG_TEXT_COMPRESSION_NONE;
2589 text_info.key = key;
2590 text_info.lang = NULL;
2591 text_info.lang_key = NULL;
2592 text_info.itxt_length = 0;
2593 text_info.text = text;
2594 text_info.text_length = strlen(text);
2596 if (png_set_text_2(png_ptr, info_ptr, &text_info, 1) != 0)
2597 png_warning(png_ptr, "Insufficient memory to process text chunk");
2601 #ifdef PNG_READ_zTXt_SUPPORTED
2602 /* Note: this does not correctly handle chunks that are > 64K under DOS */
2604 png_handle_zTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2606 png_const_charp errmsg = NULL;
2608 png_uint_32 keyword_length;
2610 png_debug(1, "in png_handle_zTXt");
2612 #ifdef PNG_USER_LIMITS_SUPPORTED
2613 if (png_ptr->user_chunk_cache_max != 0)
2615 if (png_ptr->user_chunk_cache_max == 1)
2617 png_crc_finish(png_ptr, length);
2621 if (--png_ptr->user_chunk_cache_max == 1)
2623 png_crc_finish(png_ptr, length);
2624 png_chunk_benign_error(png_ptr, "no space in chunk cache");
2630 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2631 png_chunk_error(png_ptr, "missing IHDR");
2633 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2634 png_ptr->mode |= PNG_AFTER_IDAT;
2636 /* Note, "length" is sufficient here; we won't be adding
2637 * a null terminator later.
2639 buffer = png_read_buffer(png_ptr, length, 2/*silent*/);
2643 png_crc_finish(png_ptr, length);
2644 png_chunk_benign_error(png_ptr, "out of memory");
2648 png_crc_read(png_ptr, buffer, length);
2650 if (png_crc_finish(png_ptr, 0) != 0)
2653 /* TODO: also check that the keyword contents match the spec! */
2654 for (keyword_length = 0;
2655 keyword_length < length && buffer[keyword_length] != 0;
2657 /* Empty loop to find end of name */ ;
2659 if (keyword_length > 79 || keyword_length < 1)
2660 errmsg = "bad keyword";
2662 /* zTXt must have some LZ data after the keyword, although it may expand to
2663 * zero bytes; we need a '\0' at the end of the keyword, the compression type
2666 else if (keyword_length + 3 > length)
2667 errmsg = "truncated";
2669 else if (buffer[keyword_length+1] != PNG_COMPRESSION_TYPE_BASE)
2670 errmsg = "unknown compression type";
2674 png_alloc_size_t uncompressed_length = PNG_SIZE_MAX;
2676 /* TODO: at present png_decompress_chunk imposes a single application
2677 * level memory limit, this should be split to different values for iCCP
2680 if (png_decompress_chunk(png_ptr, length, keyword_length+2,
2681 &uncompressed_length, 1/*terminate*/) == Z_STREAM_END)
2685 if (png_ptr->read_buffer == NULL)
2686 errmsg="Read failure in png_handle_zTXt";
2689 /* It worked; png_ptr->read_buffer now looks like a tEXt chunk
2690 * except for the extra compression type byte and the fact that
2691 * it isn't necessarily '\0' terminated.
2693 buffer = png_ptr->read_buffer;
2694 buffer[uncompressed_length+(keyword_length+2)] = 0;
2696 text.compression = PNG_TEXT_COMPRESSION_zTXt;
2697 text.key = (png_charp)buffer;
2698 text.text = (png_charp)(buffer + keyword_length+2);
2699 text.text_length = uncompressed_length;
2700 text.itxt_length = 0;
2702 text.lang_key = NULL;
2704 if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0)
2705 errmsg = "insufficient memory";
2710 errmsg = png_ptr->zstream.msg;
2714 png_chunk_benign_error(png_ptr, errmsg);
2718 #ifdef PNG_READ_iTXt_SUPPORTED
2719 /* Note: this does not correctly handle chunks that are > 64K under DOS */
2721 png_handle_iTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
2723 png_const_charp errmsg = NULL;
2725 png_uint_32 prefix_length;
2727 png_debug(1, "in png_handle_iTXt");
2729 #ifdef PNG_USER_LIMITS_SUPPORTED
2730 if (png_ptr->user_chunk_cache_max != 0)
2732 if (png_ptr->user_chunk_cache_max == 1)
2734 png_crc_finish(png_ptr, length);
2738 if (--png_ptr->user_chunk_cache_max == 1)
2740 png_crc_finish(png_ptr, length);
2741 png_chunk_benign_error(png_ptr, "no space in chunk cache");
2747 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
2748 png_chunk_error(png_ptr, "missing IHDR");
2750 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
2751 png_ptr->mode |= PNG_AFTER_IDAT;
2753 buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/);
2757 png_crc_finish(png_ptr, length);
2758 png_chunk_benign_error(png_ptr, "out of memory");
2762 png_crc_read(png_ptr, buffer, length);
2764 if (png_crc_finish(png_ptr, 0) != 0)
2767 /* First the keyword. */
2768 for (prefix_length=0;
2769 prefix_length < length && buffer[prefix_length] != 0;
2773 /* Perform a basic check on the keyword length here. */
2774 if (prefix_length > 79 || prefix_length < 1)
2775 errmsg = "bad keyword";
2777 /* Expect keyword, compression flag, compression type, language, translated
2778 * keyword (both may be empty but are 0 terminated) then the text, which may
2781 else if (prefix_length + 5 > length)
2782 errmsg = "truncated";
2784 else if (buffer[prefix_length+1] == 0 ||
2785 (buffer[prefix_length+1] == 1 &&
2786 buffer[prefix_length+2] == PNG_COMPRESSION_TYPE_BASE))
2788 int compressed = buffer[prefix_length+1] != 0;
2789 png_uint_32 language_offset, translated_keyword_offset;
2790 png_alloc_size_t uncompressed_length = 0;
2792 /* Now the language tag */
2794 language_offset = prefix_length;
2796 for (; prefix_length < length && buffer[prefix_length] != 0;
2800 /* WARNING: the length may be invalid here, this is checked below. */
2801 translated_keyword_offset = ++prefix_length;
2803 for (; prefix_length < length && buffer[prefix_length] != 0;
2807 /* prefix_length should now be at the trailing '\0' of the translated
2808 * keyword, but it may already be over the end. None of this arithmetic
2809 * can overflow because chunks are at most 2^31 bytes long, but on 16-bit
2810 * systems the available allocation may overflow.
2814 if (compressed == 0 && prefix_length <= length)
2815 uncompressed_length = length - prefix_length;
2817 else if (compressed != 0 && prefix_length < length)
2819 uncompressed_length = PNG_SIZE_MAX;
2821 /* TODO: at present png_decompress_chunk imposes a single application
2822 * level memory limit, this should be split to different values for
2823 * iCCP and text chunks.
2825 if (png_decompress_chunk(png_ptr, length, prefix_length,
2826 &uncompressed_length, 1/*terminate*/) == Z_STREAM_END)
2827 buffer = png_ptr->read_buffer;
2830 errmsg = png_ptr->zstream.msg;
2834 errmsg = "truncated";
2840 buffer[uncompressed_length+prefix_length] = 0;
2842 if (compressed == 0)
2843 text.compression = PNG_ITXT_COMPRESSION_NONE;
2846 text.compression = PNG_ITXT_COMPRESSION_zTXt;
2848 text.key = (png_charp)buffer;
2849 text.lang = (png_charp)buffer + language_offset;
2850 text.lang_key = (png_charp)buffer + translated_keyword_offset;
2851 text.text = (png_charp)buffer + prefix_length;
2852 text.text_length = 0;
2853 text.itxt_length = uncompressed_length;
2855 if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0)
2856 errmsg = "insufficient memory";
2861 errmsg = "bad compression info";
2864 png_chunk_benign_error(png_ptr, errmsg);
2868 #ifdef PNG_READ_APNG_SUPPORTED
2870 png_handle_acTL(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
2873 png_uint_32 num_frames;
2874 png_uint_32 num_plays;
2877 png_debug(1, "in png_handle_acTL");
2879 if (!(png_ptr->mode & PNG_HAVE_IHDR))
2881 png_error(png_ptr, "Missing IHDR before acTL");
2883 else if (png_ptr->mode & PNG_HAVE_IDAT)
2885 png_warning(png_ptr, "Invalid acTL after IDAT skipped");
2886 png_crc_finish(png_ptr, length);
2889 else if (png_ptr->mode & PNG_HAVE_acTL)
2891 png_warning(png_ptr, "Duplicate acTL skipped");
2892 png_crc_finish(png_ptr, length);
2895 else if (length != 8)
2897 png_warning(png_ptr, "acTL with invalid length skipped");
2898 png_crc_finish(png_ptr, length);
2902 png_crc_read(png_ptr, data, 8);
2903 png_crc_finish(png_ptr, 0);
2905 num_frames = png_get_uint_31(png_ptr, data);
2906 num_plays = png_get_uint_31(png_ptr, data + 4);
2908 /* the set function will do error checking on num_frames */
2909 didSet = png_set_acTL(png_ptr, info_ptr, num_frames, num_plays);
2911 png_ptr->mode |= PNG_HAVE_acTL;
2915 png_handle_fcTL(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
2920 png_uint_32 x_offset;
2921 png_uint_32 y_offset;
2922 png_uint_16 delay_num;
2923 png_uint_16 delay_den;
2924 png_byte dispose_op;
2927 png_debug(1, "in png_handle_fcTL");
2929 png_ensure_sequence_number(png_ptr, length);
2931 if (!(png_ptr->mode & PNG_HAVE_IHDR))
2933 png_error(png_ptr, "Missing IHDR before fcTL");
2935 else if (png_ptr->mode & PNG_HAVE_IDAT)
2937 /* for any frames other then the first this message may be misleading,
2938 * but correct. PNG_HAVE_IDAT is unset before the frame head is read
2939 * i can't think of a better message */
2940 png_warning(png_ptr, "Invalid fcTL after IDAT skipped");
2941 png_crc_finish(png_ptr, length-4);
2944 else if (png_ptr->mode & PNG_HAVE_fcTL)
2946 png_warning(png_ptr, "Duplicate fcTL within one frame skipped");
2947 png_crc_finish(png_ptr, length-4);
2950 else if (length != 26)
2952 png_warning(png_ptr, "fcTL with invalid length skipped");
2953 png_crc_finish(png_ptr, length-4);
2957 png_crc_read(png_ptr, data, 22);
2958 png_crc_finish(png_ptr, 0);
2960 width = png_get_uint_31(png_ptr, data);
2961 height = png_get_uint_31(png_ptr, data + 4);
2962 x_offset = png_get_uint_31(png_ptr, data + 8);
2963 y_offset = png_get_uint_31(png_ptr, data + 12);
2964 delay_num = png_get_uint_16(data + 16);
2965 delay_den = png_get_uint_16(data + 18);
2966 dispose_op = data[20];
2967 blend_op = data[21];
2969 if (png_ptr->num_frames_read == 0 && (x_offset != 0 || y_offset != 0))
2971 png_warning(png_ptr, "fcTL for the first frame must have zero offset");
2975 if (info_ptr != NULL)
2977 if (png_ptr->num_frames_read == 0 &&
2978 (width != info_ptr->width || height != info_ptr->height))
2980 png_warning(png_ptr, "size in first frame's fcTL must match "
2981 "the size in IHDR");
2985 /* The set function will do more error checking */
2986 png_set_next_frame_fcTL(png_ptr, info_ptr, width, height,
2987 x_offset, y_offset, delay_num, delay_den,
2988 dispose_op, blend_op);
2990 png_read_reinit(png_ptr, info_ptr);
2992 png_ptr->mode |= PNG_HAVE_fcTL;
2997 png_have_info(png_structp png_ptr, png_infop info_ptr)
2999 if((info_ptr->valid & PNG_INFO_acTL) && !(info_ptr->valid & PNG_INFO_fcTL))
3001 png_ptr->apng_flags |= PNG_FIRST_FRAME_HIDDEN;
3002 info_ptr->num_frames++;
3007 png_handle_fdAT(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
3009 png_ensure_sequence_number(png_ptr, length);
3011 /* This function is only called from png_read_end(), png_read_info(),
3012 * and png_push_read_chunk() which means that:
3013 * - the user doesn't want to read this frame
3014 * - or this is an out-of-place fdAT
3015 * in either case it is safe to ignore the chunk with a warning */
3016 png_warning(png_ptr, "ignoring fdAT chunk");
3017 png_crc_finish(png_ptr, length - 4);
3018 PNG_UNUSED(info_ptr)
3022 png_ensure_sequence_number(png_structp png_ptr, png_uint_32 length)
3025 png_uint_32 sequence_number;
3028 png_error(png_ptr, "invalid fcTL or fdAT chunk found");
3030 png_crc_read(png_ptr, data, 4);
3031 sequence_number = png_get_uint_31(png_ptr, data);
3033 if (sequence_number != png_ptr->next_seq_num)
3034 png_error(png_ptr, "fcTL or fdAT chunk with out-of-order sequence "
3037 png_ptr->next_seq_num++;
3039 #endif /* PNG_READ_APNG_SUPPORTED */
3041 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
3042 /* Utility function for png_handle_unknown; set up png_ptr::unknown_chunk */
3044 png_cache_unknown_chunk(png_structrp png_ptr, png_uint_32 length)
3046 png_alloc_size_t limit = PNG_SIZE_MAX;
3048 if (png_ptr->unknown_chunk.data != NULL)
3050 png_free(png_ptr, png_ptr->unknown_chunk.data);
3051 png_ptr->unknown_chunk.data = NULL;
3054 # ifdef PNG_SET_USER_LIMITS_SUPPORTED
3055 if (png_ptr->user_chunk_malloc_max > 0 &&
3056 png_ptr->user_chunk_malloc_max < limit)
3057 limit = png_ptr->user_chunk_malloc_max;
3059 # elif PNG_USER_CHUNK_MALLOC_MAX > 0
3060 if (PNG_USER_CHUNK_MALLOC_MAX < limit)
3061 limit = PNG_USER_CHUNK_MALLOC_MAX;
3064 if (length <= limit)
3066 PNG_CSTRING_FROM_CHUNK(png_ptr->unknown_chunk.name, png_ptr->chunk_name);
3067 /* The following is safe because of the PNG_SIZE_MAX init above */
3068 png_ptr->unknown_chunk.size = (size_t)length/*SAFE*/;
3069 /* 'mode' is a flag array, only the bottom four bits matter here */
3070 png_ptr->unknown_chunk.location = (png_byte)png_ptr->mode/*SAFE*/;
3073 png_ptr->unknown_chunk.data = NULL;
3077 /* Do a 'warn' here - it is handled below. */
3078 png_ptr->unknown_chunk.data = png_voidcast(png_bytep,
3079 png_malloc_warn(png_ptr, length));
3083 if (png_ptr->unknown_chunk.data == NULL && length > 0)
3085 /* This is benign because we clean up correctly */
3086 png_crc_finish(png_ptr, length);
3087 png_chunk_benign_error(png_ptr, "unknown chunk exceeds memory limits");
3094 png_crc_read(png_ptr, png_ptr->unknown_chunk.data, length);
3095 png_crc_finish(png_ptr, 0);
3099 #endif /* READ_UNKNOWN_CHUNKS */
3101 /* Handle an unknown, or known but disabled, chunk */
3103 png_handle_unknown(png_structrp png_ptr, png_inforp info_ptr,
3104 png_uint_32 length, int keep)
3106 int handled = 0; /* the chunk was handled */
3108 png_debug(1, "in png_handle_unknown");
3110 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
3111 /* NOTE: this code is based on the code in libpng-1.4.12 except for fixing
3112 * the bug which meant that setting a non-default behavior for a specific
3113 * chunk would be ignored (the default was always used unless a user
3114 * callback was installed).
3116 * 'keep' is the value from the png_chunk_unknown_handling, the setting for
3117 * this specific chunk_name, if PNG_HANDLE_AS_UNKNOWN_SUPPORTED, if not it
3118 * will always be PNG_HANDLE_CHUNK_AS_DEFAULT and it needs to be set here.
3119 * This is just an optimization to avoid multiple calls to the lookup
3122 # ifndef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
3123 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
3124 keep = png_chunk_unknown_handling(png_ptr, png_ptr->chunk_name);
3128 /* One of the following methods will read the chunk or skip it (at least one
3129 * of these is always defined because this is the only way to switch on
3130 * PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
3132 # ifdef PNG_READ_USER_CHUNKS_SUPPORTED
3133 /* The user callback takes precedence over the chunk keep value, but the
3134 * keep value is still required to validate a save of a critical chunk.
3136 if (png_ptr->read_user_chunk_fn != NULL)
3138 if (png_cache_unknown_chunk(png_ptr, length) != 0)
3140 /* Callback to user unknown chunk handler */
3141 int ret = (*(png_ptr->read_user_chunk_fn))(png_ptr,
3142 &png_ptr->unknown_chunk);
3145 * negative: An error occurred; png_chunk_error will be called.
3146 * zero: The chunk was not handled, the chunk will be discarded
3147 * unless png_set_keep_unknown_chunks has been used to set
3148 * a 'keep' behavior for this particular chunk, in which
3149 * case that will be used. A critical chunk will cause an
3150 * error at this point unless it is to be saved.
3151 * positive: The chunk was handled, libpng will ignore/discard it.
3154 png_chunk_error(png_ptr, "error in user chunk");
3158 /* If the keep value is 'default' or 'never' override it, but
3159 * still error out on critical chunks unless the keep value is
3160 * 'always' While this is weird it is the behavior in 1.4.12.
3161 * A possible improvement would be to obey the value set for the
3162 * chunk, but this would be an API change that would probably
3163 * damage some applications.
3165 * The png_app_warning below catches the case that matters, where
3166 * the application has not set specific save or ignore for this
3167 * chunk or global save or ignore.
3169 if (keep < PNG_HANDLE_CHUNK_IF_SAFE)
3171 # ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
3172 if (png_ptr->unknown_default < PNG_HANDLE_CHUNK_IF_SAFE)
3174 png_chunk_warning(png_ptr, "Saving unknown chunk:");
3175 png_app_warning(png_ptr,
3176 "forcing save of an unhandled chunk;"
3177 " please call png_set_keep_unknown_chunks");
3178 /* with keep = PNG_HANDLE_CHUNK_IF_SAFE */
3181 keep = PNG_HANDLE_CHUNK_IF_SAFE;
3185 else /* chunk was handled */
3188 /* Critical chunks can be safely discarded at this point. */
3189 keep = PNG_HANDLE_CHUNK_NEVER;
3194 keep = PNG_HANDLE_CHUNK_NEVER; /* insufficient memory */
3198 /* Use the SAVE_UNKNOWN_CHUNKS code or skip the chunk */
3199 # endif /* READ_USER_CHUNKS */
3201 # ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
3203 /* keep is currently just the per-chunk setting, if there was no
3204 * setting change it to the global default now (not that this may
3205 * still be AS_DEFAULT) then obtain the cache of the chunk if required,
3206 * if not simply skip the chunk.
3208 if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT)
3209 keep = png_ptr->unknown_default;
3211 if (keep == PNG_HANDLE_CHUNK_ALWAYS ||
3212 (keep == PNG_HANDLE_CHUNK_IF_SAFE &&
3213 PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)))
3215 if (png_cache_unknown_chunk(png_ptr, length) == 0)
3216 keep = PNG_HANDLE_CHUNK_NEVER;
3220 png_crc_finish(png_ptr, length);
3223 # ifndef PNG_READ_USER_CHUNKS_SUPPORTED
3224 # error no method to support READ_UNKNOWN_CHUNKS
3228 /* If here there is no read callback pointer set and no support is
3229 * compiled in to just save the unknown chunks, so simply skip this
3230 * chunk. If 'keep' is something other than AS_DEFAULT or NEVER then
3231 * the app has erroneously asked for unknown chunk saving when there
3234 if (keep > PNG_HANDLE_CHUNK_NEVER)
3235 png_app_error(png_ptr, "no unknown chunk support available");
3237 png_crc_finish(png_ptr, length);
3241 # ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
3242 /* Now store the chunk in the chunk list if appropriate, and if the limits
3245 if (keep == PNG_HANDLE_CHUNK_ALWAYS ||
3246 (keep == PNG_HANDLE_CHUNK_IF_SAFE &&
3247 PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)))
3249 # ifdef PNG_USER_LIMITS_SUPPORTED
3250 switch (png_ptr->user_chunk_cache_max)
3253 png_ptr->user_chunk_cache_max = 1;
3254 png_chunk_benign_error(png_ptr, "no space in chunk cache");
3257 /* NOTE: prior to 1.6.0 this case resulted in an unknown critical
3258 * chunk being skipped, now there will be a hard error below.
3262 default: /* not at limit */
3263 --(png_ptr->user_chunk_cache_max);
3265 case 0: /* no limit */
3266 # endif /* USER_LIMITS */
3267 /* Here when the limit isn't reached or when limits are compiled
3268 * out; store the chunk.
3270 png_set_unknown_chunks(png_ptr, info_ptr,
3271 &png_ptr->unknown_chunk, 1);
3273 # ifdef PNG_USER_LIMITS_SUPPORTED
3278 # else /* no store support: the chunk must be handled by the user callback */
3279 PNG_UNUSED(info_ptr)
3282 /* Regardless of the error handling below the cached data (if any) can be
3283 * freed now. Notice that the data is not freed if there is a png_error, but
3284 * it will be freed by destroy_read_struct.
3286 if (png_ptr->unknown_chunk.data != NULL)
3287 png_free(png_ptr, png_ptr->unknown_chunk.data);
3288 png_ptr->unknown_chunk.data = NULL;
3290 #else /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */
3291 /* There is no support to read an unknown chunk, so just skip it. */
3292 png_crc_finish(png_ptr, length);
3293 PNG_UNUSED(info_ptr)
3295 #endif /* !READ_UNKNOWN_CHUNKS */
3297 /* Check for unhandled critical chunks */
3298 if (handled == 0 && PNG_CHUNK_CRITICAL(png_ptr->chunk_name))
3299 png_chunk_error(png_ptr, "unhandled critical chunk");
3302 /* This function is called to verify that a chunk name is valid.
3303 * This function can't have the "critical chunk check" incorporated
3304 * into it, since in the future we will need to be able to call user
3305 * functions to handle unknown critical chunks after we check that
3306 * the chunk name itself is valid.
3309 /* Bit hacking: the test for an invalid byte in the 4 byte chunk name is:
3311 * ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
3315 png_check_chunk_name(png_const_structrp png_ptr, png_uint_32 chunk_name)
3318 png_uint_32 cn=chunk_name;
3320 png_debug(1, "in png_check_chunk_name");
3322 for (i=1; i<=4; ++i)
3326 if (c < 65 || c > 122 || (c > 90 && c < 97))
3327 png_chunk_error(png_ptr, "invalid chunk type");
3334 png_check_chunk_length(png_const_structrp png_ptr, png_uint_32 length)
3336 png_alloc_size_t limit = PNG_UINT_31_MAX;
3338 # ifdef PNG_SET_USER_LIMITS_SUPPORTED
3339 if (png_ptr->user_chunk_malloc_max > 0 &&
3340 png_ptr->user_chunk_malloc_max < limit)
3341 limit = png_ptr->user_chunk_malloc_max;
3342 # elif PNG_USER_CHUNK_MALLOC_MAX > 0
3343 if (PNG_USER_CHUNK_MALLOC_MAX < limit)
3344 limit = PNG_USER_CHUNK_MALLOC_MAX;
3346 if (png_ptr->chunk_name == png_IDAT)
3348 png_alloc_size_t idat_limit = PNG_UINT_31_MAX;
3350 (size_t)png_ptr->width
3351 * (size_t)png_ptr->channels
3352 * (png_ptr->bit_depth > 8? 2: 1)
3354 + (png_ptr->interlaced? 6: 0);
3355 if (png_ptr->height > PNG_UINT_32_MAX/row_factor)
3356 idat_limit = PNG_UINT_31_MAX;
3358 idat_limit = png_ptr->height * row_factor;
3359 row_factor = row_factor > 32566? 32566 : row_factor;
3360 idat_limit += 6 + 5*(idat_limit/row_factor+1); /* zlib+deflate overhead */
3361 idat_limit=idat_limit < PNG_UINT_31_MAX? idat_limit : PNG_UINT_31_MAX;
3362 limit = limit < idat_limit? idat_limit : limit;
3367 png_debug2(0," length = %lu, limit = %lu",
3368 (unsigned long)length,(unsigned long)limit);
3369 png_chunk_error(png_ptr, "chunk data is too large");
3376 copy_src_to_dst(png_bytep dp, png_bytep sp, int width,
3377 int row_stride, int nplanes, PngPickColor *png_pickcolor)
3380 unsigned char *src = (unsigned char *)sp;
3381 unsigned char *dst = (unsigned char *)dp;
3383 unsigned long long sumRGBA[4] = {0, 0, 0, 0};
3384 const int const0 = 0;
3387 uint32x4_t sumR_32x4 = vmovq_n_u32 ( 0 );
3388 uint32x4_t sumG_32x4 = vmovq_n_u32 ( 0 );
3389 uint32x4_t sumB_32x4 = vmovq_n_u32 ( 0 );
3395 uint64x1x3_t sumRGB_64x1;
3397 for(j = 0; j < width-(width&0xf); j += 16)
3401 uint8x16x3_t rgb = vld3q_u8 ( src );
3403 R_8x16 = rgb.val[0];
3404 G_8x16 = rgb.val[1];
3405 B_8x16 = rgb.val[2];
3409 uint8x16x4_t rgb = vld4q_u8 ( src );
3411 R_8x16 = rgb.val[0];
3412 G_8x16 = rgb.val[1];
3413 B_8x16 = rgb.val[2];
3416 if(png_pickcolor && png_pickcolor->enable)
3418 if(png_pickcolor->perc > 0)
3420 uint16x8_t sumR_16x8 = vpaddlq_u8 ( R_8x16 );
3421 uint16x8_t sumG_16x8 = vpaddlq_u8 ( G_8x16 );
3422 uint16x8_t sumB_16x8 = vpaddlq_u8 ( B_8x16 );
3424 sumR_32x4 = vpadalq_u16 ( sumR_32x4, sumR_16x8 );
3425 sumG_32x4 = vpadalq_u16 ( sumG_32x4, sumG_16x8 );
3426 sumB_32x4 = vpadalq_u16 ( sumB_32x4, sumB_16x8 );
3428 else if( (png_pickcolor->x1 > j) && (png_pickcolor->x1 < j + 16) )
3430 int x = png_pickcolor->x1;
3431 unsigned char *from = sp + (png_pickcolor->x1 * nplanes);
3434 png_pickcolor->sumR += from[0];
3435 png_pickcolor->sumG += from[1];
3436 png_pickcolor->sumB += from[2];
3441 else if( (png_pickcolor->x2 >= j) && (png_pickcolor->x2 < j + 16) )
3444 unsigned char *from = sp + (j * nplanes);
3445 while(x <= png_pickcolor->x2)
3447 png_pickcolor->sumR += from[0];
3448 png_pickcolor->sumG += from[1];
3449 png_pickcolor->sumB += from[2];
3454 else if ( (j >= png_pickcolor->x1) && (j+15 <= png_pickcolor->x2) )
3456 uint16x8_t sumR_16x8 = vpaddlq_u8 ( R_8x16 );
3457 uint16x8_t sumG_16x8 = vpaddlq_u8 ( G_8x16 );
3458 uint16x8_t sumB_16x8 = vpaddlq_u8 ( B_8x16 );
3460 sumR_32x4 = vpadalq_u16 ( sumR_32x4, sumR_16x8 );
3461 sumG_32x4 = vpadalq_u16 ( sumG_32x4, sumG_16x8 );
3462 sumB_32x4 = vpadalq_u16 ( sumB_32x4, sumB_16x8 );
3465 dst += (nplanes*16);
3466 src += (nplanes*16);
3469 if(png_pickcolor && png_pickcolor->enable)
3472 uint64x2_t sumR_64x2 = vpaddlq_u32 ( sumR_32x4 );
3473 uint64x2_t sumG_64x2 = vpaddlq_u32 ( sumG_32x4 );
3474 uint64x2_t sumB_64x2 = vpaddlq_u32 ( sumB_32x4 );
3476 uint64x1_t sumR_Lo_64x1 = vget_low_u64 ( sumR_64x2 );
3477 uint64x1_t sumR_Hi_64x1 = vget_high_u64 ( sumR_64x2 );
3479 uint64x1_t sumG_Lo_64x1 = vget_low_u64 ( sumG_64x2 );
3480 uint64x1_t sumG_Hi_64x1 = vget_high_u64 ( sumG_64x2 );
3482 uint64x1_t sumB_Lo_64x1 = vget_low_u64 ( sumB_64x2 );
3483 uint64x1_t sumB_Hi_64x1 = vget_high_u64 ( sumB_64x2 );
3485 sumRGB_64x1.val[0] = vadd_u64 ( sumR_Lo_64x1, sumR_Hi_64x1 );
3486 sumRGB_64x1.val[1] = vadd_u64 ( sumG_Lo_64x1, sumG_Hi_64x1 );
3487 sumRGB_64x1.val[2] = vadd_u64 ( sumB_Lo_64x1, sumB_Hi_64x1 );
3489 vst3_u64( sumRGBA, sumRGB_64x1);
3491 png_pickcolor->sumR += sumRGBA[0];
3492 png_pickcolor->sumG += sumRGBA[1];
3493 png_pickcolor->sumB += sumRGBA[2];
3496 memcpy(dst, src, (width-j)*nplanes);
3497 if(png_pickcolor && png_pickcolor->enable)
3499 if(png_pickcolor->perc <= 0)
3501 if(j < png_pickcolor->x1)
3503 j = png_pickcolor->x1;
3504 dst = dp + (j*nplanes);
3506 width = png_pickcolor->x2;
3508 for(; j < width ; j ++)
3510 png_pickcolor->sumR += dst[0];
3511 png_pickcolor->sumG += dst[1];
3512 png_pickcolor->sumB += dst[2];
3518 void copy_row(png_bytep dp, png_bytep sp, int width, int pixel_bits, PngPickColor *png_pickcolor)
3520 int row_stride = PNG_ROWBYTES(pixel_bits, width);
3521 if(pixel_bits == 24 || pixel_bits == 32)
3523 copy_src_to_dst(dp, sp, width, row_stride, pixel_bits >> 3, png_pickcolor);
3527 memcpy(dp, sp, row_stride);
3532 #endif /* __TIZEN__ */
3534 /* Combines the row recently read in with the existing pixels in the row. This
3535 * routine takes care of alpha and transparency if requested. This routine also
3536 * handles the two methods of progressive display of interlaced images,
3537 * depending on the 'display' value; if 'display' is true then the whole row
3538 * (dp) is filled from the start by replicating the available pixels. If
3539 * 'display' is false only those pixels present in the pass are filled in.
3542 png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display)
3544 unsigned int pixel_depth = png_ptr->transformed_pixel_depth;
3545 png_const_bytep sp = png_ptr->row_buf + 1;
3546 png_alloc_size_t row_width = png_ptr->width;
3547 unsigned int pass = png_ptr->pass;
3548 png_bytep end_ptr = 0;
3549 png_byte end_byte = 0;
3550 unsigned int end_mask;
3552 png_debug(1, "in png_combine_row");
3554 /* Added in 1.5.6: it should not be possible to enter this routine until at
3555 * least one row has been read from the PNG data and transformed.
3557 if (pixel_depth == 0)
3558 png_error(png_ptr, "internal row logic error");
3560 /* Added in 1.5.4: the pixel depth should match the information returned by
3561 * any call to png_read_update_info at this point. Do not continue if we got
3564 if (png_ptr->info_rowbytes != 0 && png_ptr->info_rowbytes !=
3565 PNG_ROWBYTES(pixel_depth, row_width))
3566 png_error(png_ptr, "internal row size calculation error");
3568 /* Don't expect this to ever happen: */
3570 png_error(png_ptr, "internal row width error");
3572 /* Preserve the last byte in cases where only part of it will be overwritten,
3573 * the multiply below may overflow, we don't care because ANSI-C guarantees
3574 * we get the low bits.
3576 end_mask = (pixel_depth * row_width) & 7;
3579 /* end_ptr == NULL is a flag to say do nothing */
3580 end_ptr = dp + PNG_ROWBYTES(pixel_depth, row_width) - 1;
3581 end_byte = *end_ptr;
3582 # ifdef PNG_READ_PACKSWAP_SUPPORTED
3583 if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
3584 /* little-endian byte */
3585 end_mask = (unsigned int)(0xff << end_mask);
3587 else /* big-endian byte */
3589 end_mask = 0xff >> end_mask;
3590 /* end_mask is now the bits to *keep* from the destination row */
3593 /* For non-interlaced images this reduces to a memcpy(). A memcpy()
3594 * will also happen if interlacing isn't supported or if the application
3595 * does not call png_set_interlace_handling(). In the latter cases the
3596 * caller just gets a sequence of the unexpanded rows from each interlace
3599 #ifdef PNG_READ_INTERLACING_SUPPORTED
3600 if (png_ptr->interlaced != 0 &&
3601 (png_ptr->transformations & PNG_INTERLACE) != 0 &&
3602 pass < 6 && (display == 0 ||
3603 /* The following copies everything for 'display' on passes 0, 2 and 4. */
3604 (display == 1 && (pass & 1) != 0)))
3606 /* Narrow images may have no bits in a pass; the caller should handle
3607 * this, but this test is cheap:
3609 if (row_width <= PNG_PASS_START_COL(pass))
3612 if (pixel_depth < 8)
3614 /* For pixel depths up to 4 bpp the 8-pixel mask can be expanded to fit
3615 * into 32 bits, then a single loop over the bytes using the four byte
3616 * values in the 32-bit mask can be used. For the 'display' option the
3617 * expanded mask may also not require any masking within a byte. To
3618 * make this work the PACKSWAP option must be taken into account - it
3619 * simply requires the pixels to be reversed in each byte.
3621 * The 'regular' case requires a mask for each of the first 6 passes,
3622 * the 'display' case does a copy for the even passes in the range
3623 * 0..6. This has already been handled in the test above.
3625 * The masks are arranged as four bytes with the first byte to use in
3626 * the lowest bits (little-endian) regardless of the order (PACKSWAP or
3627 * not) of the pixels in each byte.
3629 * NOTE: the whole of this logic depends on the caller of this function
3630 * only calling it on rows appropriate to the pass. This function only
3631 * understands the 'x' logic; the 'y' logic is handled by the caller.
3633 * The following defines allow generation of compile time constant bit
3634 * masks for each pixel depth and each possibility of swapped or not
3635 * swapped bytes. Pass 'p' is in the range 0..6; 'x', a pixel index,
3636 * is in the range 0..7; and the result is 1 if the pixel is to be
3637 * copied in the pass, 0 if not. 'S' is for the sparkle method, 'B'
3638 * for the block method.
3640 * With some compilers a compile time expression of the general form:
3642 * (shift >= 32) ? (a >> (shift-32)) : (b >> shift)
3644 * Produces warnings with values of 'shift' in the range 33 to 63
3645 * because the right hand side of the ?: expression is evaluated by
3646 * the compiler even though it isn't used. Microsoft Visual C (various
3647 * versions) and the Intel C compiler are known to do this. To avoid
3648 * this the following macros are used in 1.5.6. This is a temporary
3649 * solution to avoid destabilizing the code during the release process.
3651 # if PNG_USE_COMPILE_TIME_MASKS
3652 # define PNG_LSR(x,s) ((x)>>((s) & 0x1f))
3653 # define PNG_LSL(x,s) ((x)<<((s) & 0x1f))
3655 # define PNG_LSR(x,s) ((x)>>(s))
3656 # define PNG_LSL(x,s) ((x)<<(s))
3658 # define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\
3659 PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1)
3660 # define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\
3661 PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1)
3663 /* Return a mask for pass 'p' pixel 'x' at depth 'd'. The mask is
3664 * little endian - the first pixel is at bit 0 - however the extra
3665 * parameter 's' can be set to cause the mask position to be swapped
3666 * within each byte, to match the PNG format. This is done by XOR of
3667 * the shift with 7, 6 or 4 for bit depths 1, 2 and 4.
3669 # define PIXEL_MASK(p,x,d,s) \
3670 (PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0))))
3672 /* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask.
3674 # define S_MASKx(p,x,d,s) (S_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
3675 # define B_MASKx(p,x,d,s) (B_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
3677 /* Combine 8 of these to get the full mask. For the 1-bpp and 2-bpp
3678 * cases the result needs replicating, for the 4-bpp case the above
3679 * generates a full 32 bits.
3681 # define MASK_EXPAND(m,d) ((m)*((d)==1?0x01010101:((d)==2?0x00010001:1)))
3683 # define S_MASK(p,d,s) MASK_EXPAND(S_MASKx(p,0,d,s) + S_MASKx(p,1,d,s) +\
3684 S_MASKx(p,2,d,s) + S_MASKx(p,3,d,s) + S_MASKx(p,4,d,s) +\
3685 S_MASKx(p,5,d,s) + S_MASKx(p,6,d,s) + S_MASKx(p,7,d,s), d)
3687 # define B_MASK(p,d,s) MASK_EXPAND(B_MASKx(p,0,d,s) + B_MASKx(p,1,d,s) +\
3688 B_MASKx(p,2,d,s) + B_MASKx(p,3,d,s) + B_MASKx(p,4,d,s) +\
3689 B_MASKx(p,5,d,s) + B_MASKx(p,6,d,s) + B_MASKx(p,7,d,s), d)
3691 #if PNG_USE_COMPILE_TIME_MASKS
3692 /* Utility macros to construct all the masks for a depth/swap
3693 * combination. The 's' parameter says whether the format is PNG
3694 * (big endian bytes) or not. Only the three odd-numbered passes are
3695 * required for the display/block algorithm.
3697 # define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\
3698 S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) }
3700 # define B_MASKS(d,s) { B_MASK(1,d,s), B_MASK(3,d,s), B_MASK(5,d,s) }
3702 # define DEPTH_INDEX(d) ((d)==1?0:((d)==2?1:2))
3704 /* Hence the pre-compiled masks indexed by PACKSWAP (or not), depth and
3707 static const png_uint_32 row_mask[2/*PACKSWAP*/][3/*depth*/][6] =
3709 /* Little-endian byte masks for PACKSWAP */
3710 { S_MASKS(1,0), S_MASKS(2,0), S_MASKS(4,0) },
3711 /* Normal (big-endian byte) masks - PNG format */
3712 { S_MASKS(1,1), S_MASKS(2,1), S_MASKS(4,1) }
3715 /* display_mask has only three entries for the odd passes, so index by
3718 static const png_uint_32 display_mask[2][3][3] =
3720 /* Little-endian byte masks for PACKSWAP */
3721 { B_MASKS(1,0), B_MASKS(2,0), B_MASKS(4,0) },
3722 /* Normal (big-endian byte) masks - PNG format */
3723 { B_MASKS(1,1), B_MASKS(2,1), B_MASKS(4,1) }
3726 # define MASK(pass,depth,display,png)\
3727 ((display)?display_mask[png][DEPTH_INDEX(depth)][pass>>1]:\
3728 row_mask[png][DEPTH_INDEX(depth)][pass])
3730 #else /* !PNG_USE_COMPILE_TIME_MASKS */
3731 /* This is the runtime alternative: it seems unlikely that this will
3732 * ever be either smaller or faster than the compile time approach.
3734 # define MASK(pass,depth,display,png)\
3735 ((display)?B_MASK(pass,depth,png):S_MASK(pass,depth,png))
3736 #endif /* !USE_COMPILE_TIME_MASKS */
3738 /* Use the appropriate mask to copy the required bits. In some cases
3739 * the byte mask will be 0 or 0xff; optimize these cases. row_width is
3740 * the number of pixels, but the code copies bytes, so it is necessary
3741 * to special case the end.
3743 png_uint_32 pixels_per_byte = 8 / pixel_depth;
3746 # ifdef PNG_READ_PACKSWAP_SUPPORTED
3747 if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
3748 mask = MASK(pass, pixel_depth, display, 0);
3752 mask = MASK(pass, pixel_depth, display, 1);
3758 /* It doesn't matter in the following if png_uint_32 has more than
3759 * 32 bits because the high bits always match those in m<<24; it is,
3760 * however, essential to use OR here, not +, because of this.
3763 mask = (m >> 8) | (m << 24); /* rotate right to good compilers */
3766 if (m != 0) /* something to copy */
3769 *dp = (png_byte)((*dp & ~m) | (*sp & m));
3774 /* NOTE: this may overwrite the last byte with garbage if the image
3775 * is not an exact number of bytes wide; libpng has always done
3778 if (row_width <= pixels_per_byte)
3779 break; /* May need to restore part of the last byte */
3781 row_width -= pixels_per_byte;
3787 else /* pixel_depth >= 8 */
3789 unsigned int bytes_to_copy, bytes_to_jump;
3791 /* Validate the depth - it must be a multiple of 8 */
3792 if (pixel_depth & 7)
3793 png_error(png_ptr, "invalid user transform pixel depth");
3795 pixel_depth >>= 3; /* now in bytes */
3796 row_width *= pixel_depth;
3798 /* Regardless of pass number the Adam 7 interlace always results in a
3799 * fixed number of pixels to copy then to skip. There may be a
3800 * different number of pixels to skip at the start though.
3803 unsigned int offset = PNG_PASS_START_COL(pass) * pixel_depth;
3805 row_width -= offset;
3810 /* Work out the bytes to copy. */
3813 /* When doing the 'block' algorithm the pixel in the pass gets
3814 * replicated to adjacent pixels. This is why the even (0,2,4,6)
3815 * passes are skipped above - the entire expanded row is copied.
3817 bytes_to_copy = (1<<((6-pass)>>1)) * pixel_depth;
3819 /* But don't allow this number to exceed the actual row width. */
3820 if (bytes_to_copy > row_width)
3821 bytes_to_copy = (unsigned int)/*SAFE*/row_width;
3824 else /* normal row; Adam7 only ever gives us one pixel to copy. */
3825 bytes_to_copy = pixel_depth;
3827 /* In Adam7 there is a constant offset between where the pixels go. */
3828 bytes_to_jump = PNG_PASS_COL_OFFSET(pass) * pixel_depth;
3830 /* And simply copy these bytes. Some optimization is possible here,
3831 * depending on the value of 'bytes_to_copy'. Special case the low
3832 * byte counts, which we know to be frequent.
3834 * Notice that these cases all 'return' rather than 'break' - this
3835 * avoids an unnecessary test on whether to restore the last byte
3838 switch (bytes_to_copy)
3845 if (row_width <= bytes_to_jump)
3848 dp += bytes_to_jump;
3849 sp += bytes_to_jump;
3850 row_width -= bytes_to_jump;
3854 /* There is a possibility of a partial copy at the end here; this
3855 * slows the code down somewhat.
3859 dp[0] = sp[0]; dp[1] = sp[1];
3861 if (row_width <= bytes_to_jump)
3864 sp += bytes_to_jump;
3865 dp += bytes_to_jump;
3866 row_width -= bytes_to_jump;
3868 while (row_width > 1);
3870 /* And there can only be one byte left at this point: */
3875 /* This can only be the RGB case, so each copy is exactly one
3876 * pixel and it is not necessary to check for a partial copy.
3880 dp[0] = sp[0]; dp[1] = sp[1]; dp[2] = sp[2];
3882 if (row_width <= bytes_to_jump)
3885 sp += bytes_to_jump;
3886 dp += bytes_to_jump;
3887 row_width -= bytes_to_jump;
3891 #if PNG_ALIGN_TYPE != PNG_ALIGN_NONE
3892 /* Check for double byte alignment and, if possible, use a
3893 * 16-bit copy. Don't attempt this for narrow images - ones that
3894 * are less than an interlace panel wide. Don't attempt it for
3895 * wide bytes_to_copy either - use the memcpy there.
3897 if (bytes_to_copy < 16 /*else use memcpy*/ &&
3898 png_isaligned(dp, png_uint_16) &&
3899 png_isaligned(sp, png_uint_16) &&
3900 bytes_to_copy % (sizeof (png_uint_16)) == 0 &&
3901 bytes_to_jump % (sizeof (png_uint_16)) == 0)
3903 /* Everything is aligned for png_uint_16 copies, but try for
3904 * png_uint_32 first.
3906 if (png_isaligned(dp, png_uint_32) &&
3907 png_isaligned(sp, png_uint_32) &&
3908 bytes_to_copy % (sizeof (png_uint_32)) == 0 &&
3909 bytes_to_jump % (sizeof (png_uint_32)) == 0)
3911 png_uint_32p dp32 = png_aligncast(png_uint_32p,dp);
3912 png_const_uint_32p sp32 = png_aligncastconst(
3913 png_const_uint_32p, sp);
3914 size_t skip = (bytes_to_jump-bytes_to_copy) /
3915 (sizeof (png_uint_32));
3919 size_t c = bytes_to_copy;
3923 c -= (sizeof (png_uint_32));
3927 if (row_width <= bytes_to_jump)
3932 row_width -= bytes_to_jump;
3934 while (bytes_to_copy <= row_width);
3936 /* Get to here when the row_width truncates the final copy.
3937 * There will be 1-3 bytes left to copy, so don't try the
3938 * 16-bit loop below.
3940 dp = (png_bytep)dp32;
3941 sp = (png_const_bytep)sp32;
3944 while (--row_width > 0);
3948 /* Else do it in 16-bit quantities, but only if the size is
3953 png_uint_16p dp16 = png_aligncast(png_uint_16p, dp);
3954 png_const_uint_16p sp16 = png_aligncastconst(
3955 png_const_uint_16p, sp);
3956 size_t skip = (bytes_to_jump-bytes_to_copy) /
3957 (sizeof (png_uint_16));
3961 size_t c = bytes_to_copy;
3965 c -= (sizeof (png_uint_16));
3969 if (row_width <= bytes_to_jump)
3974 row_width -= bytes_to_jump;
3976 while (bytes_to_copy <= row_width);
3978 /* End of row - 1 byte left, bytes_to_copy > row_width: */
3979 dp = (png_bytep)dp16;
3980 sp = (png_const_bytep)sp16;
3983 while (--row_width > 0);
3987 #endif /* ALIGN_TYPE code */
3989 /* The true default - use a memcpy: */
3992 memcpy(dp, sp, bytes_to_copy);
3994 if (row_width <= bytes_to_jump)
3997 sp += bytes_to_jump;
3998 dp += bytes_to_jump;
3999 row_width -= bytes_to_jump;
4000 if (bytes_to_copy > row_width)
4001 bytes_to_copy = (unsigned int)/*SAFE*/row_width;
4006 } /* pixel_depth >= 8 */
4008 /* Here if pixel_depth < 8 to check 'end_ptr' below. */
4011 #endif /* READ_INTERLACING */
4013 /* If here then the switch above wasn't used so just memcpy the whole row
4014 * from the temporary row buffer (notice that this overwrites the end of the
4015 * destination row if it is a partial byte.)
4017 memcpy(dp, sp, PNG_ROWBYTES(pixel_depth, row_width));
4019 /* Restore the overwritten bits from the last byte if necessary. */
4020 if (end_ptr != NULL)
4021 *end_ptr = (png_byte)((end_byte & end_mask) | (*end_ptr & ~end_mask));
4024 #ifdef PNG_READ_INTERLACING_SUPPORTED
4026 png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
4027 png_uint_32 transformations /* Because these may affect the byte layout */)
4029 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
4030 /* Offset to next interlace block */
4031 static const unsigned int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
4033 png_debug(1, "in png_do_read_interlace");
4034 if (row != NULL && row_info != NULL)
4036 png_uint_32 final_width;
4038 final_width = row_info->width * png_pass_inc[pass];
4040 switch (row_info->pixel_depth)
4044 png_bytep sp = row + (size_t)((row_info->width - 1) >> 3);
4045 png_bytep dp = row + (size_t)((final_width - 1) >> 3);
4046 unsigned int sshift, dshift;
4047 unsigned int s_start, s_end;
4049 int jstop = (int)png_pass_inc[pass];
4054 #ifdef PNG_READ_PACKSWAP_SUPPORTED
4055 if ((transformations & PNG_PACKSWAP) != 0)
4057 sshift = ((row_info->width + 7) & 0x07);
4058 dshift = ((final_width + 7) & 0x07);
4067 sshift = 7 - ((row_info->width + 7) & 0x07);
4068 dshift = 7 - ((final_width + 7) & 0x07);
4074 for (i = 0; i < row_info->width; i++)
4076 v = (png_byte)((*sp >> sshift) & 0x01);
4077 for (j = 0; j < jstop; j++)
4079 unsigned int tmp = *dp & (0x7f7f >> (7 - dshift));
4080 tmp |= (unsigned int)(v << dshift);
4081 *dp = (png_byte)(tmp & 0xff);
4083 if (dshift == s_end)
4090 dshift = (unsigned int)((int)dshift + s_inc);
4093 if (sshift == s_end)
4100 sshift = (unsigned int)((int)sshift + s_inc);
4107 png_bytep sp = row + (png_uint_32)((row_info->width - 1) >> 2);
4108 png_bytep dp = row + (png_uint_32)((final_width - 1) >> 2);
4109 unsigned int sshift, dshift;
4110 unsigned int s_start, s_end;
4112 int jstop = (int)png_pass_inc[pass];
4115 #ifdef PNG_READ_PACKSWAP_SUPPORTED
4116 if ((transformations & PNG_PACKSWAP) != 0)
4118 sshift = (((row_info->width + 3) & 0x03) << 1);
4119 dshift = (((final_width + 3) & 0x03) << 1);
4128 sshift = ((3 - ((row_info->width + 3) & 0x03)) << 1);
4129 dshift = ((3 - ((final_width + 3) & 0x03)) << 1);
4135 for (i = 0; i < row_info->width; i++)
4140 v = (png_byte)((*sp >> sshift) & 0x03);
4141 for (j = 0; j < jstop; j++)
4143 unsigned int tmp = *dp & (0x3f3f >> (6 - dshift));
4144 tmp |= (unsigned int)(v << dshift);
4145 *dp = (png_byte)(tmp & 0xff);
4147 if (dshift == s_end)
4154 dshift = (unsigned int)((int)dshift + s_inc);
4157 if (sshift == s_end)
4164 sshift = (unsigned int)((int)sshift + s_inc);
4171 png_bytep sp = row + (size_t)((row_info->width - 1) >> 1);
4172 png_bytep dp = row + (size_t)((final_width - 1) >> 1);
4173 unsigned int sshift, dshift;
4174 unsigned int s_start, s_end;
4177 int jstop = (int)png_pass_inc[pass];
4179 #ifdef PNG_READ_PACKSWAP_SUPPORTED
4180 if ((transformations & PNG_PACKSWAP) != 0)
4182 sshift = (((row_info->width + 1) & 0x01) << 2);
4183 dshift = (((final_width + 1) & 0x01) << 2);
4192 sshift = ((1 - ((row_info->width + 1) & 0x01)) << 2);
4193 dshift = ((1 - ((final_width + 1) & 0x01)) << 2);
4199 for (i = 0; i < row_info->width; i++)
4201 png_byte v = (png_byte)((*sp >> sshift) & 0x0f);
4204 for (j = 0; j < jstop; j++)
4206 unsigned int tmp = *dp & (0xf0f >> (4 - dshift));
4207 tmp |= (unsigned int)(v << dshift);
4208 *dp = (png_byte)(tmp & 0xff);
4210 if (dshift == s_end)
4217 dshift = (unsigned int)((int)dshift + s_inc);
4220 if (sshift == s_end)
4227 sshift = (unsigned int)((int)sshift + s_inc);
4234 size_t pixel_bytes = (row_info->pixel_depth >> 3);
4236 png_bytep sp = row + (size_t)(row_info->width - 1)
4239 png_bytep dp = row + (size_t)(final_width - 1) * pixel_bytes;
4241 int jstop = (int)png_pass_inc[pass];
4244 for (i = 0; i < row_info->width; i++)
4246 png_byte v[8]; /* SAFE; pixel_depth does not exceed 64 */
4249 memcpy(v, sp, pixel_bytes);
4251 for (j = 0; j < jstop; j++)
4253 memcpy(dp, v, pixel_bytes);
4263 row_info->width = final_width;
4264 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, final_width);
4266 #ifndef PNG_READ_PACKSWAP_SUPPORTED
4267 PNG_UNUSED(transformations) /* Silence compiler warning */
4270 #endif /* READ_INTERLACING */
4273 png_read_filter_row_sub(png_row_infop row_info, png_bytep row,
4274 png_const_bytep prev_row)
4277 size_t istop = row_info->rowbytes;
4278 unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
4279 png_bytep rp = row + bpp;
4281 PNG_UNUSED(prev_row)
4283 for (i = bpp; i < istop; i++)
4285 *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
4291 png_read_filter_row_up(png_row_infop row_info, png_bytep row,
4292 png_const_bytep prev_row)
4295 size_t istop = row_info->rowbytes;
4297 png_const_bytep pp = prev_row;
4299 for (i = 0; i < istop; i++)
4301 *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
4307 png_read_filter_row_avg(png_row_infop row_info, png_bytep row,
4308 png_const_bytep prev_row)
4312 png_const_bytep pp = prev_row;
4313 unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
4314 size_t istop = row_info->rowbytes - bpp;
4316 for (i = 0; i < bpp; i++)
4318 *rp = (png_byte)(((int)(*rp) +
4319 ((int)(*pp++) / 2 )) & 0xff);
4324 for (i = 0; i < istop; i++)
4326 *rp = (png_byte)(((int)(*rp) +
4327 (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
4334 png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info, png_bytep row,
4335 png_const_bytep prev_row)
4337 png_bytep rp_end = row + row_info->rowbytes;
4340 /* First pixel/byte */
4343 *row++ = (png_byte)a;
4346 while (row < rp_end)
4348 int b, pa, pb, pc, p;
4350 a &= 0xff; /* From previous iteration or start */
4361 pa = p < 0 ? -p : p;
4362 pb = pc < 0 ? -pc : pc;
4363 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
4366 /* Find the best predictor, the least of pa, pb, pc favoring the earlier
4367 * ones in the case of a tie.
4375 /* Calculate the current pixel in a, and move the previous row pixel to c
4376 * for the next time round the loop
4380 *row++ = (png_byte)a;
4385 png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row,
4386 png_const_bytep prev_row)
4388 unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
4389 png_bytep rp_end = row + bpp;
4391 /* Process the first pixel in the row completely (this is the same as 'up'
4392 * because there is only one candidate predictor for the first row).
4394 while (row < rp_end)
4396 int a = *row + *prev_row++;
4397 *row++ = (png_byte)a;
4401 rp_end = rp_end + (row_info->rowbytes - bpp);
4403 while (row < rp_end)
4405 int a, b, c, pa, pb, pc, p;
4407 c = *(prev_row - bpp);
4419 pa = p < 0 ? -p : p;
4420 pb = pc < 0 ? -pc : pc;
4421 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
4431 *row++ = (png_byte)a;
4436 png_init_filter_functions(png_structrp pp)
4437 /* This function is called once for every PNG image (except for PNG images
4438 * that only use PNG_FILTER_VALUE_NONE for all rows) to set the
4439 * implementations required to reverse the filtering of PNG rows. Reversing
4440 * the filter is the first transformation performed on the row data. It is
4441 * performed in place, therefore an implementation can be selected based on
4442 * the image pixel format. If the implementation depends on image width then
4443 * take care to ensure that it works correctly if the image is interlaced -
4444 * interlacing causes the actual row width to vary.
4447 unsigned int bpp = (pp->pixel_depth + 7) >> 3;
4449 pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub;
4450 pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up;
4451 pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg;
4453 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
4454 png_read_filter_row_paeth_1byte_pixel;
4456 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
4457 png_read_filter_row_paeth_multibyte_pixel;
4459 #ifdef PNG_FILTER_OPTIMIZATIONS
4460 /* To use this define PNG_FILTER_OPTIMIZATIONS as the name of a function to
4461 * call to install hardware optimizations for the above functions; simply
4462 * replace whatever elements of the pp->read_filter[] array with a hardware
4463 * specific (or, for that matter, generic) optimization.
4465 * To see an example of this examine what configure.ac does when
4466 * --enable-arm-neon is specified on the command line.
4468 PNG_FILTER_OPTIMIZATIONS(pp, bpp);
4473 png_read_filter_row(png_structrp pp, png_row_infop row_info, png_bytep row,
4474 png_const_bytep prev_row, int filter)
4476 /* OPTIMIZATION: DO NOT MODIFY THIS FUNCTION, instead #define
4477 * PNG_FILTER_OPTIMIZATIONS to a function that overrides the generic
4478 * implementations. See png_init_filter_functions above.
4480 if (filter > PNG_FILTER_VALUE_NONE && filter < PNG_FILTER_VALUE_LAST)
4482 if (pp->read_filter[0] == NULL)
4483 png_init_filter_functions(pp);
4485 pp->read_filter[filter-1](row_info, row, prev_row);
4489 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
4491 png_read_IDAT_data(png_structrp png_ptr, png_bytep output,
4492 png_alloc_size_t avail_out)
4494 /* Loop reading IDATs and decompressing the result into output[avail_out] */
4495 png_ptr->zstream.next_out = output;
4496 png_ptr->zstream.avail_out = 0; /* safety: set below */
4504 png_byte tmpbuf[PNG_INFLATE_BUF_SIZE];
4506 if (png_ptr->zstream.avail_in == 0)
4510 #ifdef PNG_READ_APNG_SUPPORTED
4511 png_uint_32 bytes_to_skip = 0;
4513 while (png_ptr->idat_size == 0 || bytes_to_skip != 0)
4515 png_crc_finish(png_ptr, bytes_to_skip);
4518 png_ptr->idat_size = png_read_chunk_header(png_ptr);
4519 if (png_ptr->num_frames_read == 0)
4521 if (png_ptr->chunk_name != png_IDAT)
4522 png_error(png_ptr, "Not enough image data");
4526 if (png_ptr->chunk_name == png_IEND)
4527 png_error(png_ptr, "Not enough image data");
4528 if (png_ptr->chunk_name != png_fdAT)
4530 png_warning(png_ptr, "Skipped (ignored) a chunk "
4531 "between APNG chunks");
4532 bytes_to_skip = png_ptr->idat_size;
4536 png_ensure_sequence_number(png_ptr, png_ptr->idat_size);
4538 png_ptr->idat_size -= 4;
4542 while (png_ptr->idat_size == 0)
4544 png_crc_finish(png_ptr, 0);
4546 png_ptr->idat_size = png_read_chunk_header(png_ptr);
4547 /* This is an error even in the 'check' case because the code just
4548 * consumed a non-IDAT header.
4550 if (png_ptr->chunk_name != png_IDAT)
4551 png_error(png_ptr, "Not enough image data");
4553 #endif /* PNG_READ_APNG_SUPPORTED */
4554 avail_in = png_ptr->IDAT_read_size;
4556 if (avail_in > png_ptr->idat_size)
4557 avail_in = (uInt)png_ptr->idat_size;
4559 /* A PNG with a gradually increasing IDAT size will defeat this attempt
4560 * to minimize memory usage by causing lots of re-allocs, but
4561 * realistically doing IDAT_read_size re-allocs is not likely to be a
4564 buffer = png_read_buffer(png_ptr, avail_in, 0/*error*/);
4566 png_crc_read(png_ptr, buffer, avail_in);
4567 png_ptr->idat_size -= avail_in;
4569 png_ptr->zstream.next_in = buffer;
4570 png_ptr->zstream.avail_in = avail_in;
4573 /* And set up the output side. */
4574 if (output != NULL) /* standard read */
4576 uInt out = ZLIB_IO_MAX;
4578 if (out > avail_out)
4579 out = (uInt)avail_out;
4582 png_ptr->zstream.avail_out = out;
4585 else /* after last row, checking for end */
4587 png_ptr->zstream.next_out = tmpbuf;
4588 png_ptr->zstream.avail_out = (sizeof tmpbuf);
4591 /* Use NO_FLUSH; this gives zlib the maximum opportunity to optimize the
4592 * process. If the LZ stream is truncated the sequential reader will
4593 * terminally damage the stream, above, by reading the chunk header of the
4594 * following chunk (it then exits with png_error).
4596 * TODO: deal more elegantly with truncated IDAT lists.
4598 ret = PNG_INFLATE(png_ptr, Z_NO_FLUSH);
4600 /* Take the unconsumed output back. */
4602 avail_out += png_ptr->zstream.avail_out;
4604 else /* avail_out counts the extra bytes */
4605 avail_out += (sizeof tmpbuf) - png_ptr->zstream.avail_out;
4607 png_ptr->zstream.avail_out = 0;
4609 if (ret == Z_STREAM_END)
4611 /* Do this for safety; we won't read any more into this row. */
4612 png_ptr->zstream.next_out = NULL;
4614 png_ptr->mode |= PNG_AFTER_IDAT;
4615 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
4616 #ifdef PNG_READ_APNG_SUPPORTED
4617 png_ptr->num_frames_read++;
4620 if (png_ptr->zstream.avail_in > 0 || png_ptr->idat_size > 0)
4621 png_chunk_benign_error(png_ptr, "Extra compressed data");
4627 png_zstream_error(png_ptr, ret);
4630 png_chunk_error(png_ptr, png_ptr->zstream.msg);
4634 png_chunk_benign_error(png_ptr, png_ptr->zstream.msg);
4638 } while (avail_out > 0);
4642 /* The stream ended before the image; this is the same as too few IDATs so
4643 * should be handled the same way.
4646 png_error(png_ptr, "Not enough image data");
4648 else /* the deflate stream contained extra data */
4649 png_chunk_benign_error(png_ptr, "Too much image data");
4654 png_read_finish_IDAT(png_structrp png_ptr)
4656 /* We don't need any more data and the stream should have ended, however the
4657 * LZ end code may actually not have been processed. In this case we must
4658 * read it otherwise stray unread IDAT data or, more likely, an IDAT chunk
4659 * may still remain to be consumed.
4661 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
4663 /* The NULL causes png_read_IDAT_data to swallow any remaining bytes in
4664 * the compressed stream, but the stream may be damaged too, so even after
4665 * this call we may need to terminate the zstream ownership.
4667 png_read_IDAT_data(png_ptr, NULL, 0);
4668 png_ptr->zstream.next_out = NULL; /* safety */
4670 /* Now clear everything out for safety; the following may not have been
4673 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
4675 png_ptr->mode |= PNG_AFTER_IDAT;
4676 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
4680 /* If the zstream has not been released do it now *and* terminate the reading
4681 * of the final IDAT chunk.
4683 if (png_ptr->zowner == png_IDAT)
4685 /* Always do this; the pointers otherwise point into the read buffer. */
4686 png_ptr->zstream.next_in = NULL;
4687 png_ptr->zstream.avail_in = 0;
4689 /* Now we no longer own the zstream. */
4690 png_ptr->zowner = 0;
4692 /* The slightly weird semantics of the sequential IDAT reading is that we
4693 * are always in or at the end of an IDAT chunk, so we always need to do a
4694 * crc_finish here. If idat_size is non-zero we also need to read the
4695 * spurious bytes at the end of the chunk now.
4697 (void)png_crc_finish(png_ptr, png_ptr->idat_size);
4702 png_read_finish_row(png_structrp png_ptr)
4704 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
4706 /* Start of interlace block */
4707 static const png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
4709 /* Offset to next interlace block */
4710 static const png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
4712 /* Start of interlace block in the y direction */
4713 static const png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
4715 /* Offset to next interlace block in the y direction */
4716 static const png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
4718 png_debug(1, "in png_read_finish_row");
4719 png_ptr->row_number++;
4720 if (png_ptr->row_number < png_ptr->num_rows)
4723 if (png_ptr->interlaced != 0)
4725 png_ptr->row_number = 0;
4727 /* TO DO: don't do this if prev_row isn't needed (requires
4728 * read-ahead of the next row's filter byte.
4730 memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
4736 if (png_ptr->pass >= 7)
4739 png_ptr->iwidth = (png_ptr->width +
4740 png_pass_inc[png_ptr->pass] - 1 -
4741 png_pass_start[png_ptr->pass]) /
4742 png_pass_inc[png_ptr->pass];
4744 if ((png_ptr->transformations & PNG_INTERLACE) == 0)
4746 png_ptr->num_rows = (png_ptr->height +
4747 png_pass_yinc[png_ptr->pass] - 1 -
4748 png_pass_ystart[png_ptr->pass]) /
4749 png_pass_yinc[png_ptr->pass];
4752 else /* if (png_ptr->transformations & PNG_INTERLACE) */
4753 break; /* libpng deinterlacing sees every row */
4755 } while (png_ptr->num_rows == 0 || png_ptr->iwidth == 0);
4757 if (png_ptr->pass < 7)
4761 /* Here after at the end of the last row of the last pass. */
4762 png_read_finish_IDAT(png_ptr);
4764 #endif /* SEQUENTIAL_READ */
4767 png_read_start_row(png_structrp png_ptr)
4769 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
4771 /* Start of interlace block */
4772 static const png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
4774 /* Offset to next interlace block */
4775 static const png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
4777 /* Start of interlace block in the y direction */
4778 static const png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
4780 /* Offset to next interlace block in the y direction */
4781 static const png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
4783 unsigned int max_pixel_depth;
4786 png_debug(1, "in png_read_start_row");
4788 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
4789 png_init_read_transformations(png_ptr);
4791 if (png_ptr->interlaced != 0)
4793 if ((png_ptr->transformations & PNG_INTERLACE) == 0)
4794 png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
4795 png_pass_ystart[0]) / png_pass_yinc[0];
4798 png_ptr->num_rows = png_ptr->height;
4800 png_ptr->iwidth = (png_ptr->width +
4801 png_pass_inc[png_ptr->pass] - 1 -
4802 png_pass_start[png_ptr->pass]) /
4803 png_pass_inc[png_ptr->pass];
4808 png_ptr->num_rows = png_ptr->height;
4809 png_ptr->iwidth = png_ptr->width;
4812 max_pixel_depth = (unsigned int)png_ptr->pixel_depth;
4814 /* WARNING: * png_read_transform_info (pngrtran.c) performs a simpler set of
4815 * calculations to calculate the final pixel depth, then
4816 * png_do_read_transforms actually does the transforms. This means that the
4817 * code which effectively calculates this value is actually repeated in three
4818 * separate places. They must all match. Innocent changes to the order of
4819 * transformations can and will break libpng in a way that causes memory
4824 #ifdef PNG_READ_PACK_SUPPORTED
4825 if ((png_ptr->transformations & PNG_PACK) != 0 && png_ptr->bit_depth < 8)
4826 max_pixel_depth = 8;
4829 #ifdef PNG_READ_EXPAND_SUPPORTED
4830 if ((png_ptr->transformations & PNG_EXPAND) != 0)
4832 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
4834 if (png_ptr->num_trans != 0)
4835 max_pixel_depth = 32;
4838 max_pixel_depth = 24;
4841 else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
4843 if (max_pixel_depth < 8)
4844 max_pixel_depth = 8;
4846 if (png_ptr->num_trans != 0)
4847 max_pixel_depth *= 2;
4850 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
4852 if (png_ptr->num_trans != 0)
4854 max_pixel_depth *= 4;
4855 max_pixel_depth /= 3;
4861 #ifdef PNG_READ_EXPAND_16_SUPPORTED
4862 if ((png_ptr->transformations & PNG_EXPAND_16) != 0)
4864 # ifdef PNG_READ_EXPAND_SUPPORTED
4865 /* In fact it is an error if it isn't supported, but checking is
4868 if ((png_ptr->transformations & PNG_EXPAND) != 0)
4870 if (png_ptr->bit_depth < 16)
4871 max_pixel_depth *= 2;
4875 png_ptr->transformations &= ~PNG_EXPAND_16;
4879 #ifdef PNG_READ_FILLER_SUPPORTED
4880 if ((png_ptr->transformations & (PNG_FILLER)) != 0)
4882 if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
4884 if (max_pixel_depth <= 8)
4885 max_pixel_depth = 16;
4888 max_pixel_depth = 32;
4891 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB ||
4892 png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
4894 if (max_pixel_depth <= 32)
4895 max_pixel_depth = 32;
4898 max_pixel_depth = 64;
4903 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
4904 if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0)
4907 #ifdef PNG_READ_EXPAND_SUPPORTED
4908 (png_ptr->num_trans != 0 &&
4909 (png_ptr->transformations & PNG_EXPAND) != 0) ||
4911 #ifdef PNG_READ_FILLER_SUPPORTED
4912 (png_ptr->transformations & (PNG_FILLER)) != 0 ||
4914 png_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
4916 if (max_pixel_depth <= 16)
4917 max_pixel_depth = 32;
4920 max_pixel_depth = 64;
4925 if (max_pixel_depth <= 8)
4927 if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
4928 max_pixel_depth = 32;
4931 max_pixel_depth = 24;
4934 else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
4935 max_pixel_depth = 64;
4938 max_pixel_depth = 48;
4943 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) && \
4944 defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
4945 if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
4947 unsigned int user_pixel_depth = png_ptr->user_transform_depth *
4948 png_ptr->user_transform_channels;
4950 if (user_pixel_depth > max_pixel_depth)
4951 max_pixel_depth = user_pixel_depth;
4955 /* This value is stored in png_struct and double checked in the row read
4958 png_ptr->maximum_pixel_depth = (png_byte)max_pixel_depth;
4959 png_ptr->transformed_pixel_depth = 0; /* calculated on demand */
4961 /* Align the width on the next larger 8 pixels. Mainly used
4964 row_bytes = ((png_ptr->width + 7) & ~((png_uint_32)7));
4965 /* Calculate the maximum bytes needed, adding a byte and a pixel
4968 row_bytes = PNG_ROWBYTES(max_pixel_depth, row_bytes) +
4969 1 + ((max_pixel_depth + 7) >> 3U);
4971 #ifdef PNG_MAX_MALLOC_64K
4972 if (row_bytes > (png_uint_32)65536L)
4973 png_error(png_ptr, "This image requires a row greater than 64KB");
4976 if (row_bytes + 48 > png_ptr->old_big_row_buf_size)
4978 png_free(png_ptr, png_ptr->big_row_buf);
4979 png_free(png_ptr, png_ptr->big_prev_row);
4981 if (png_ptr->interlaced != 0)
4982 png_ptr->big_row_buf = (png_bytep)png_calloc(png_ptr,
4986 png_ptr->big_row_buf = (png_bytep)png_malloc(png_ptr, row_bytes + 48);
4988 png_ptr->big_prev_row = (png_bytep)png_malloc(png_ptr, row_bytes + 48);
4990 #ifdef PNG_ALIGNED_MEMORY_SUPPORTED
4991 /* Use 16-byte aligned memory for row_buf with at least 16 bytes
4992 * of padding before and after row_buf; treat prev_row similarly.
4993 * NOTE: the alignment is to the start of the pixels, one beyond the start
4994 * of the buffer, because of the filter byte. Prior to libpng 1.5.6 this
4995 * was incorrect; the filter byte was aligned, which had the exact
4996 * opposite effect of that intended.
4999 png_bytep temp = png_ptr->big_row_buf + 32;
5000 int extra = (int)((temp - (png_bytep)0) & 0x0f);
5001 png_ptr->row_buf = temp - extra - 1/*filter byte*/;
5003 temp = png_ptr->big_prev_row + 32;
5004 extra = (int)((temp - (png_bytep)0) & 0x0f);
5005 png_ptr->prev_row = temp - extra - 1/*filter byte*/;
5009 /* Use 31 bytes of padding before and 17 bytes after row_buf. */
5010 png_ptr->row_buf = png_ptr->big_row_buf + 31;
5011 png_ptr->prev_row = png_ptr->big_prev_row + 31;
5013 png_ptr->old_big_row_buf_size = row_bytes + 48;
5016 #ifdef PNG_MAX_MALLOC_64K
5017 if (png_ptr->rowbytes > 65535)
5018 png_error(png_ptr, "This image requires a row greater than 64KB");
5021 if (png_ptr->rowbytes > (PNG_SIZE_MAX - 1))
5022 png_error(png_ptr, "Row has too many bytes to allocate in memory");
5024 memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
5026 png_debug1(3, "width = %u,", png_ptr->width);
5027 png_debug1(3, "height = %u,", png_ptr->height);
5028 png_debug1(3, "iwidth = %u,", png_ptr->iwidth);
5029 png_debug1(3, "num_rows = %u,", png_ptr->num_rows);
5030 png_debug1(3, "rowbytes = %lu,", (unsigned long)png_ptr->rowbytes);
5031 png_debug1(3, "irowbytes = %lu",
5032 (unsigned long)PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->iwidth) + 1);
5034 /* The sequential reader needs a buffer for IDAT, but the progressive reader
5035 * does not, so free the read buffer now regardless; the sequential reader
5036 * reallocates it on demand.
5038 if (png_ptr->read_buffer != NULL)
5040 png_bytep buffer = png_ptr->read_buffer;
5042 png_ptr->read_buffer_size = 0;
5043 png_ptr->read_buffer = NULL;
5044 png_free(png_ptr, buffer);
5047 /* Finally claim the zstream for the inflate of the IDAT data, use the bits
5048 * value from the stream (note that this will result in a fatal error if the
5049 * IDAT stream has a bogus deflate header window_bits value, but this should
5050 * not be happening any longer!)
5052 if (png_inflate_claim(png_ptr, png_IDAT) != Z_OK)
5053 png_error(png_ptr, png_ptr->zstream.msg);
5055 png_ptr->flags |= PNG_FLAG_ROW_INIT;
5058 #ifdef PNG_READ_APNG_SUPPORTED
5059 /* This function is to be called after the main IDAT set has been read and
5060 * before a new IDAT is read. It resets some parts of png_ptr
5061 * to make them usable by the read functions again */
5063 png_read_reset(png_structp png_ptr)
5065 png_ptr->mode &= ~PNG_HAVE_IDAT;
5066 png_ptr->mode &= ~PNG_AFTER_IDAT;
5067 png_ptr->row_number = 0;
5072 png_read_reinit(png_structp png_ptr, png_infop info_ptr)
5074 png_ptr->width = info_ptr->next_frame_width;
5075 png_ptr->height = info_ptr->next_frame_height;
5076 png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth,png_ptr->width);
5077 png_ptr->info_rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth,
5079 if (png_ptr->prev_row)
5080 memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
5083 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
5084 /* same as png_read_reset() but for the progressive reader */
5086 png_progressive_read_reset(png_structp png_ptr)
5088 #ifdef PNG_READ_INTERLACING_SUPPORTED
5089 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
5091 /* Start of interlace block */
5092 const int png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
5094 /* Offset to next interlace block */
5095 const int png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
5097 /* Start of interlace block in the y direction */
5098 const int png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
5100 /* Offset to next interlace block in the y direction */
5101 const int png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
5103 if (png_ptr->interlaced)
5105 if (!(png_ptr->transformations & PNG_INTERLACE))
5106 png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
5107 png_pass_ystart[0]) / png_pass_yinc[0];
5109 png_ptr->num_rows = png_ptr->height;
5111 png_ptr->iwidth = (png_ptr->width +
5112 png_pass_inc[png_ptr->pass] - 1 -
5113 png_pass_start[png_ptr->pass]) /
5114 png_pass_inc[png_ptr->pass];
5117 #endif /* PNG_READ_INTERLACING_SUPPORTED */
5119 png_ptr->num_rows = png_ptr->height;
5120 png_ptr->iwidth = png_ptr->width;
5122 png_ptr->flags &= ~PNG_FLAG_ZSTREAM_ENDED;
5123 if (inflateReset(&(png_ptr->zstream)) != Z_OK)
5124 png_error(png_ptr, "inflateReset failed");
5125 png_ptr->zstream.avail_in = 0;
5126 png_ptr->zstream.next_in = 0;
5127 png_ptr->zstream.next_out = png_ptr->row_buf;
5128 png_ptr->zstream.avail_out = (uInt)PNG_ROWBYTES(png_ptr->pixel_depth,
5129 png_ptr->iwidth) + 1;
5131 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
5132 #endif /* PNG_READ_APNG_SUPPORTED */