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libpng/pngrutil.c
John Bowler fcc0263191 [libpng15] Paeth filter speed improvements from work by Siarhei Siamashka. This 
changes the 'Paeth' reconstruction function to improve the GCC code
generation on x86. The changes are only part of the suggested ones;
just the changes that definitely improve speed and remain simple.
The changes also slightly increase the clarity of the code. In a
2011-11-03 18:31:00 -05:00

4108 lines
119 KiB
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/* pngrutil.c - utilities to read a PNG file
*
* Last changed in libpng 1.5.7 [(PENDING RELEASE)]
* Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
*
* This code is released under the libpng license.
* For conditions of distribution and use, see the disclaimer
* and license in png.h
*
* This file contains routines that are only called from within
* libpng itself during the course of reading an image.
*/
#include "pngpriv.h"
#ifdef PNG_READ_SUPPORTED
#define png_strtod(p,a,b) strtod(a,b)
png_uint_32 PNGAPI
png_get_uint_31(png_structp png_ptr, png_const_bytep buf)
{
png_uint_32 uval = png_get_uint_32(buf);
if (uval > PNG_UINT_31_MAX)
png_error(png_ptr, "PNG unsigned integer out of range");
return (uval);
}
#if defined(PNG_READ_gAMA_SUPPORTED) || defined(PNG_READ_cHRM_SUPPORTED)
/* The following is a variation on the above for use with the fixed
* point values used for gAMA and cHRM. Instead of png_error it
* issues a warning and returns (-1) - an invalid value because both
* gAMA and cHRM use *unsigned* integers for fixed point values.
*/
#define PNG_FIXED_ERROR (-1)
static png_fixed_point /* PRIVATE */
png_get_fixed_point(png_structp png_ptr, png_const_bytep buf)
{
png_uint_32 uval = png_get_uint_32(buf);
if (uval <= PNG_UINT_31_MAX)
return (png_fixed_point)uval; /* known to be in range */
/* The caller can turn off the warning by passing NULL. */
if (png_ptr != NULL)
png_warning(png_ptr, "PNG fixed point integer out of range");
return PNG_FIXED_ERROR;
}
#endif
#ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
/* NOTE: the read macros will obscure these definitions, so that if
* PNG_USE_READ_MACROS is set the library will not use them internally,
* but the APIs will still be available externally.
*
* The parentheses around "PNGAPI function_name" in the following three
* functions are necessary because they allow the macros to co-exist with
* these (unused but exported) functions.
*/
/* Grab an unsigned 32-bit integer from a buffer in big-endian format. */
png_uint_32 (PNGAPI
png_get_uint_32)(png_const_bytep buf)
{
png_uint_32 uval =
((png_uint_32)(*(buf )) << 24) +
((png_uint_32)(*(buf + 1)) << 16) +
((png_uint_32)(*(buf + 2)) << 8) +
((png_uint_32)(*(buf + 3)) ) ;
return uval;
}
/* Grab a signed 32-bit integer from a buffer in big-endian format. The
* data is stored in the PNG file in two's complement format and there
* is no guarantee that a 'png_int_32' is exactly 32 bits, therefore
* the following code does a two's complement to native conversion.
*/
png_int_32 (PNGAPI
png_get_int_32)(png_const_bytep buf)
{
png_uint_32 uval = png_get_uint_32(buf);
if ((uval & 0x80000000) == 0) /* non-negative */
return uval;
uval = (uval ^ 0xffffffff) + 1; /* 2's complement: -x = ~x+1 */
return -(png_int_32)uval;
}
/* Grab an unsigned 16-bit integer from a buffer in big-endian format. */
png_uint_16 (PNGAPI
png_get_uint_16)(png_const_bytep buf)
{
/* ANSI-C requires an int value to accomodate at least 16 bits so this
* works and allows the compiler not to worry about possible narrowing
* on 32 bit systems. (Pre-ANSI systems did not make integers smaller
* than 16 bits either.)
*/
unsigned int val =
((unsigned int)(*buf) << 8) +
((unsigned int)(*(buf + 1)));
return (png_uint_16)val;
}
#endif /* PNG_READ_INT_FUNCTIONS_SUPPORTED */
/* Read and check the PNG file signature */
void /* PRIVATE */
png_read_sig(png_structp png_ptr, png_infop info_ptr)
{
png_size_t num_checked, num_to_check;
/* Exit if the user application does not expect a signature. */
if (png_ptr->sig_bytes >= 8)
return;
num_checked = png_ptr->sig_bytes;
num_to_check = 8 - num_checked;
#ifdef PNG_IO_STATE_SUPPORTED
png_ptr->io_state = PNG_IO_READING | PNG_IO_SIGNATURE;
#endif
/* The signature must be serialized in a single I/O call. */
png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check);
png_ptr->sig_bytes = 8;
if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
{
if (num_checked < 4 &&
png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
png_error(png_ptr, "Not a PNG file");
else
png_error(png_ptr, "PNG file corrupted by ASCII conversion");
}
if (num_checked < 3)
png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
}
/* Read the chunk header (length + type name).
* Put the type name into png_ptr->chunk_name, and return the length.
*/
png_uint_32 /* PRIVATE */
png_read_chunk_header(png_structp png_ptr)
{
png_byte buf[8];
png_uint_32 length;
#ifdef PNG_IO_STATE_SUPPORTED
png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_HDR;
#endif
/* Read the length and the chunk name.
* This must be performed in a single I/O call.
*/
png_read_data(png_ptr, buf, 8);
length = png_get_uint_31(png_ptr, buf);
/* Put the chunk name into png_ptr->chunk_name. */
png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(buf+4);
png_debug2(0, "Reading %lx chunk, length = %lu",
(unsigned long)png_ptr->chunk_name, (unsigned long)length);
/* Reset the crc and run it over the chunk name. */
png_reset_crc(png_ptr);
png_calculate_crc(png_ptr, buf + 4, 4);
/* Check to see if chunk name is valid. */
png_check_chunk_name(png_ptr, png_ptr->chunk_name);
#ifdef PNG_IO_STATE_SUPPORTED
png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_DATA;
#endif
return length;
}
/* Read data, and (optionally) run it through the CRC. */
void /* PRIVATE */
png_crc_read(png_structp png_ptr, png_bytep buf, png_size_t length)
{
if (png_ptr == NULL)
return;
png_read_data(png_ptr, buf, length);
png_calculate_crc(png_ptr, buf, length);
}
/* Optionally skip data and then check the CRC. Depending on whether we
* are reading a ancillary or critical chunk, and how the program has set
* things up, we may calculate the CRC on the data and print a message.
* Returns '1' if there was a CRC error, '0' otherwise.
*/
int /* PRIVATE */
png_crc_finish(png_structp png_ptr, png_uint_32 skip)
{
png_size_t i;
png_size_t istop = png_ptr->zbuf_size;
for (i = (png_size_t)skip; i > istop; i -= istop)
{
png_crc_read(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
}
if (i)
{
png_crc_read(png_ptr, png_ptr->zbuf, i);
}
if (png_crc_error(png_ptr))
{
if (PNG_CHUNK_ANCILLIARY(png_ptr->chunk_name) ?
!(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) :
(png_ptr->flags & PNG_FLAG_CRC_CRITICAL_USE))
{
png_chunk_warning(png_ptr, "CRC error");
}
else
{
png_chunk_benign_error(png_ptr, "CRC error");
return (0);
}
return (1);
}
return (0);
}
/* Compare the CRC stored in the PNG file with that calculated by libpng from
* the data it has read thus far.
*/
int /* PRIVATE */
png_crc_error(png_structp png_ptr)
{
png_byte crc_bytes[4];
png_uint_32 crc;
int need_crc = 1;
if (PNG_CHUNK_ANCILLIARY(png_ptr->chunk_name))
{
if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
(PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
need_crc = 0;
}
else /* critical */
{
if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE)
need_crc = 0;
}
#ifdef PNG_IO_STATE_SUPPORTED
png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_CRC;
#endif
/* The chunk CRC must be serialized in a single I/O call. */
png_read_data(png_ptr, crc_bytes, 4);
if (need_crc)
{
crc = png_get_uint_32(crc_bytes);
return ((int)(crc != png_ptr->crc));
}
else
return (0);
}
#ifdef PNG_READ_COMPRESSED_TEXT_SUPPORTED
static png_size_t
png_inflate(png_structp png_ptr, png_bytep data, png_size_t size,
png_bytep output, png_size_t output_size)
{
png_size_t count = 0;
/* zlib can't necessarily handle more than 65535 bytes at once (i.e. it can't
* even necessarily handle 65536 bytes) because the type uInt is "16 bits or
* more". Consequently it is necessary to chunk the input to zlib. This
* code uses ZLIB_IO_MAX, from pngpriv.h, as the maximum (the maximum value
* that can be stored in a uInt.) It is possible to set ZLIB_IO_MAX to a
* lower value in pngpriv.h and this may sometimes have a performance
* advantage, because it forces access of the input data to be separated from
* at least some of the use by some period of time.
*/
png_ptr->zstream.next_in = data;
/* avail_in is set below from 'size' */
png_ptr->zstream.avail_in = 0;
while (1)
{
int ret, avail;
/* The setting of 'avail_in' used to be outside the loop; by setting it
* inside it is possible to chunk the input to zlib and simply rely on
* zlib to advance the 'next_in' pointer. This allows arbitrary amounts o
* data to be passed through zlib at the unavoidable cost of requiring a
* window save (memcpy of up to 32768 output bytes) every ZLIB_IO_MAX
* input bytes.
*/
if (png_ptr->zstream.avail_in == 0 && size > 0)
{
if (size <= ZLIB_IO_MAX)
{
/* The value is less than ZLIB_IO_MAX so the cast is safe: */
png_ptr->zstream.avail_in = (uInt)size;
size = 0;
}
else
{
png_ptr->zstream.avail_in = ZLIB_IO_MAX;
size -= ZLIB_IO_MAX;
}
}
/* Reset the output buffer each time round - we empty it
* after every inflate call.
*/
png_ptr->zstream.next_out = png_ptr->zbuf;
png_ptr->zstream.avail_out = png_ptr->zbuf_size;
ret = inflate(&png_ptr->zstream, Z_NO_FLUSH);
avail = png_ptr->zbuf_size - png_ptr->zstream.avail_out;
/* First copy/count any new output - but only if we didn't
* get an error code.
*/
if ((ret == Z_OK || ret == Z_STREAM_END) && avail > 0)
{
png_size_t space = avail; /* > 0, see above */
if (output != 0 && output_size > count)
{
png_size_t copy = output_size - count;
if (space < copy)
copy = space;
png_memcpy(output + count, png_ptr->zbuf, copy);
}
count += space;
}
if (ret == Z_OK)
continue;
/* Termination conditions - always reset the zstream, it
* must be left in inflateInit state.
*/
png_ptr->zstream.avail_in = 0;
inflateReset(&png_ptr->zstream);
if (ret == Z_STREAM_END)
return count; /* NOTE: may be zero. */
/* Now handle the error codes - the API always returns 0
* and the error message is dumped into the uncompressed
* buffer if available.
*/
# ifdef PNG_WARNINGS_SUPPORTED
{
png_const_charp msg;
if (png_ptr->zstream.msg != 0)
msg = png_ptr->zstream.msg;
else switch (ret)
{
case Z_BUF_ERROR:
msg = "Buffer error in compressed datastream";
break;
case Z_DATA_ERROR:
msg = "Data error in compressed datastream";
break;
default:
msg = "Incomplete compressed datastream";
break;
}
png_chunk_warning(png_ptr, msg);
}
# endif
/* 0 means an error - notice that this code simply ignores
* zero length compressed chunks as a result.
*/
return 0;
}
}
/*
* Decompress trailing data in a chunk. The assumption is that chunkdata
* points at an allocated area holding the contents of a chunk with a
* trailing compressed part. What we get back is an allocated area
* holding the original prefix part and an uncompressed version of the
* trailing part (the malloc area passed in is freed).
*/
void /* PRIVATE */
png_decompress_chunk(png_structp png_ptr, int comp_type,
png_size_t chunklength,
png_size_t prefix_size, png_size_t *newlength)
{
/* The caller should guarantee this */
if (prefix_size > chunklength)
{
/* The recovery is to delete the chunk. */
png_warning(png_ptr, "invalid chunklength");
prefix_size = 0; /* To delete everything */
}
else if (comp_type == PNG_COMPRESSION_TYPE_BASE)
{
png_size_t expanded_size = png_inflate(png_ptr,
(png_bytep)(png_ptr->chunkdata + prefix_size),
chunklength - prefix_size,
0, /* output */
0); /* output size */
/* Now check the limits on this chunk - if the limit fails the
* compressed data will be removed, the prefix will remain.
*/
#ifdef PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED
if (png_ptr->user_chunk_malloc_max &&
(prefix_size + expanded_size >= png_ptr->user_chunk_malloc_max - 1))
#else
# ifdef PNG_USER_CHUNK_MALLOC_MAX
if ((PNG_USER_CHUNK_MALLOC_MAX > 0) &&
prefix_size + expanded_size >= PNG_USER_CHUNK_MALLOC_MAX - 1)
# endif
#endif
png_warning(png_ptr, "Exceeded size limit while expanding chunk");
/* If the size is zero either there was an error and a message
* has already been output (warning) or the size really is zero
* and we have nothing to do - the code will exit through the
* error case below.
*/
#if defined(PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED) || \
defined(PNG_USER_CHUNK_MALLOC_MAX)
else if (expanded_size > 0)
#else
if (expanded_size > 0)
#endif
{
/* Success (maybe) - really uncompress the chunk. */
png_size_t new_size = 0;
png_charp text = (png_charp)png_malloc_warn(png_ptr,
prefix_size + expanded_size + 1);
if (text != NULL)
{
png_memcpy(text, png_ptr->chunkdata, prefix_size);
new_size = png_inflate(png_ptr,
(png_bytep)(png_ptr->chunkdata + prefix_size),
chunklength - prefix_size,
(png_bytep)(text + prefix_size), expanded_size);
text[prefix_size + expanded_size] = 0; /* just in case */
if (new_size == expanded_size)
{
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = text;
*newlength = prefix_size + expanded_size;
return; /* The success return! */
}
png_warning(png_ptr, "png_inflate logic error");
png_free(png_ptr, text);
}
else
png_warning(png_ptr, "Not enough memory to decompress chunk");
}
}
else /* if (comp_type != PNG_COMPRESSION_TYPE_BASE) */
{
PNG_WARNING_PARAMETERS(p)
png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_d, comp_type);
png_formatted_warning(png_ptr, p, "Unknown zTXt compression type @1");
/* The recovery is to simply drop the data. */
}
/* Generic error return - leave the prefix, delete the compressed
* data, reallocate the chunkdata to remove the potentially large
* amount of compressed data.
*/
{
png_charp text = (png_charp)png_malloc_warn(png_ptr, prefix_size + 1);
if (text != NULL)
{
if (prefix_size > 0)
png_memcpy(text, png_ptr->chunkdata, prefix_size);
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = text;
/* This is an extra zero in the 'uncompressed' part. */
*(png_ptr->chunkdata + prefix_size) = 0x00;
}
/* Ignore a malloc error here - it is safe. */
}
*newlength = prefix_size;
}
#endif /* PNG_READ_COMPRESSED_TEXT_SUPPORTED */
/* Read and check the IDHR chunk */
void /* PRIVATE */
png_handle_IHDR(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
{
png_byte buf[13];
png_uint_32 width, height;
int bit_depth, color_type, compression_type, filter_type;
int interlace_type;
png_debug(1, "in png_handle_IHDR");
if (png_ptr->mode & PNG_HAVE_IHDR)
png_error(png_ptr, "Out of place IHDR");
/* Check the length */
if (length != 13)
png_error(png_ptr, "Invalid IHDR chunk");
png_ptr->mode |= PNG_HAVE_IHDR;
png_crc_read(png_ptr, buf, 13);
png_crc_finish(png_ptr, 0);
width = png_get_uint_31(png_ptr, buf);
height = png_get_uint_31(png_ptr, buf + 4);
bit_depth = buf[8];
color_type = buf[9];
compression_type = buf[10];
filter_type = buf[11];
interlace_type = buf[12];
/* Set internal variables */
png_ptr->width = width;
png_ptr->height = height;
png_ptr->bit_depth = (png_byte)bit_depth;
png_ptr->interlaced = (png_byte)interlace_type;
png_ptr->color_type = (png_byte)color_type;
#ifdef PNG_MNG_FEATURES_SUPPORTED
png_ptr->filter_type = (png_byte)filter_type;
#endif
png_ptr->compression_type = (png_byte)compression_type;
/* Find number of channels */
switch (png_ptr->color_type)
{
default: /* invalid, png_set_IHDR calls png_error */
case PNG_COLOR_TYPE_GRAY:
case PNG_COLOR_TYPE_PALETTE:
png_ptr->channels = 1;
break;
case PNG_COLOR_TYPE_RGB:
png_ptr->channels = 3;
break;
case PNG_COLOR_TYPE_GRAY_ALPHA:
png_ptr->channels = 2;
break;
case PNG_COLOR_TYPE_RGB_ALPHA:
png_ptr->channels = 4;
break;
}
/* Set up other useful info */
png_ptr->pixel_depth = (png_byte)(png_ptr->bit_depth *
png_ptr->channels);
png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->width);
png_debug1(3, "bit_depth = %d", png_ptr->bit_depth);
png_debug1(3, "channels = %d", png_ptr->channels);
png_debug1(3, "rowbytes = %lu", (unsigned long)png_ptr->rowbytes);
png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth,
color_type, interlace_type, compression_type, filter_type);
}
/* Read and check the palette */
void /* PRIVATE */
png_handle_PLTE(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
{
png_color palette[PNG_MAX_PALETTE_LENGTH];
int num, i;
#ifdef PNG_POINTER_INDEXING_SUPPORTED
png_colorp pal_ptr;
#endif
png_debug(1, "in png_handle_PLTE");
if (!(png_ptr->mode & PNG_HAVE_IHDR))
png_error(png_ptr, "Missing IHDR before PLTE");
else if (png_ptr->mode & PNG_HAVE_IDAT)
{
png_warning(png_ptr, "Invalid PLTE after IDAT");
png_crc_finish(png_ptr, length);
return;
}
else if (png_ptr->mode & PNG_HAVE_PLTE)
png_error(png_ptr, "Duplicate PLTE chunk");
png_ptr->mode |= PNG_HAVE_PLTE;
if (!(png_ptr->color_type&PNG_COLOR_MASK_COLOR))
{
png_warning(png_ptr,
"Ignoring PLTE chunk in grayscale PNG");
png_crc_finish(png_ptr, length);
return;
}
#ifndef PNG_READ_OPT_PLTE_SUPPORTED
if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
{
png_crc_finish(png_ptr, length);
return;
}
#endif
if (length > 3*PNG_MAX_PALETTE_LENGTH || length % 3)
{
if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
{
png_warning(png_ptr, "Invalid palette chunk");
png_crc_finish(png_ptr, length);
return;
}
else
{
png_error(png_ptr, "Invalid palette chunk");
}
}
num = (int)length / 3;
#ifdef PNG_POINTER_INDEXING_SUPPORTED
for (i = 0, pal_ptr = palette; i < num; i++, pal_ptr++)
{
png_byte buf[3];
png_crc_read(png_ptr, buf, 3);
pal_ptr->red = buf[0];
pal_ptr->green = buf[1];
pal_ptr->blue = buf[2];
}
#else
for (i = 0; i < num; i++)
{
png_byte buf[3];
png_crc_read(png_ptr, buf, 3);
/* Don't depend upon png_color being any order */
palette[i].red = buf[0];
palette[i].green = buf[1];
palette[i].blue = buf[2];
}
#endif
/* If we actually need the PLTE chunk (ie for a paletted image), we do
* whatever the normal CRC configuration tells us. However, if we
* have an RGB image, the PLTE can be considered ancillary, so
* we will act as though it is.
*/
#ifndef PNG_READ_OPT_PLTE_SUPPORTED
if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
#endif
{
png_crc_finish(png_ptr, 0);
}
#ifndef PNG_READ_OPT_PLTE_SUPPORTED
else if (png_crc_error(png_ptr)) /* Only if we have a CRC error */
{
/* If we don't want to use the data from an ancillary chunk,
* we have two options: an error abort, or a warning and we
* ignore the data in this chunk (which should be OK, since
* it's considered ancillary for a RGB or RGBA image).
*/
if (!(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_USE))
{
if (png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN)
{
png_chunk_benign_error(png_ptr, "CRC error");
}
else
{
png_chunk_warning(png_ptr, "CRC error");
return;
}
}
/* Otherwise, we (optionally) emit a warning and use the chunk. */
else if (!(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN))
{
png_chunk_warning(png_ptr, "CRC error");
}
}
#endif
png_set_PLTE(png_ptr, info_ptr, palette, num);
#ifdef PNG_READ_tRNS_SUPPORTED
if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
{
if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS))
{
if (png_ptr->num_trans > (png_uint_16)num)
{
png_warning(png_ptr, "Truncating incorrect tRNS chunk length");
png_ptr->num_trans = (png_uint_16)num;
}
if (info_ptr->num_trans > (png_uint_16)num)
{
png_warning(png_ptr, "Truncating incorrect info tRNS chunk length");
info_ptr->num_trans = (png_uint_16)num;
}
}
}
#endif
}
void /* PRIVATE */
png_handle_IEND(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
{
png_debug(1, "in png_handle_IEND");
if (!(png_ptr->mode & PNG_HAVE_IHDR) || !(png_ptr->mode & PNG_HAVE_IDAT))
{
png_error(png_ptr, "No image in file");
}
png_ptr->mode |= (PNG_AFTER_IDAT | PNG_HAVE_IEND);
if (length != 0)
{
png_warning(png_ptr, "Incorrect IEND chunk length");
}
png_crc_finish(png_ptr, length);
PNG_UNUSED(info_ptr) /* Quiet compiler warnings about unused info_ptr */
}
#ifdef PNG_READ_gAMA_SUPPORTED
void /* PRIVATE */
png_handle_gAMA(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
{
png_fixed_point igamma;
png_byte buf[4];
png_debug(1, "in png_handle_gAMA");
if (!(png_ptr->mode & PNG_HAVE_IHDR))
png_error(png_ptr, "Missing IHDR before gAMA");
else if (png_ptr->mode & PNG_HAVE_IDAT)
{
png_warning(png_ptr, "Invalid gAMA after IDAT");
png_crc_finish(png_ptr, length);
return;
}
else if (png_ptr->mode & PNG_HAVE_PLTE)
/* Should be an error, but we can cope with it */
png_warning(png_ptr, "Out of place gAMA chunk");
if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_gAMA)
#ifdef PNG_READ_sRGB_SUPPORTED
&& !(info_ptr->valid & PNG_INFO_sRGB)
#endif
)
{
png_warning(png_ptr, "Duplicate gAMA chunk");
png_crc_finish(png_ptr, length);
return;
}
if (length != 4)
{
png_warning(png_ptr, "Incorrect gAMA chunk length");
png_crc_finish(png_ptr, length);
return;
}
png_crc_read(png_ptr, buf, 4);
if (png_crc_finish(png_ptr, 0))
return;
igamma = png_get_fixed_point(NULL, buf);
/* Check for zero gamma or an error. */
if (igamma <= 0)
{
png_warning(png_ptr,
"Ignoring gAMA chunk with out of range gamma");
return;
}
# ifdef PNG_READ_sRGB_SUPPORTED
if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sRGB))
{
if (PNG_OUT_OF_RANGE(igamma, 45500, 500))
{
PNG_WARNING_PARAMETERS(p)
png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_fixed, igamma);
png_formatted_warning(png_ptr, p,
"Ignoring incorrect gAMA value @1 when sRGB is also present");
return;
}
}
# endif /* PNG_READ_sRGB_SUPPORTED */
# ifdef PNG_READ_GAMMA_SUPPORTED
/* Gamma correction on read is supported. */
png_ptr->gamma = igamma;
# endif
/* And set the 'info' structure members. */
png_set_gAMA_fixed(png_ptr, info_ptr, igamma);
}
#endif
#ifdef PNG_READ_sBIT_SUPPORTED
void /* PRIVATE */
png_handle_sBIT(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
{
png_size_t truelen;
png_byte buf[4];
png_debug(1, "in png_handle_sBIT");
buf[0] = buf[1] = buf[2] = buf[3] = 0;
if (!(png_ptr->mode & PNG_HAVE_IHDR))
png_error(png_ptr, "Missing IHDR before sBIT");
else if (png_ptr->mode & PNG_HAVE_IDAT)
{
png_warning(png_ptr, "Invalid sBIT after IDAT");
png_crc_finish(png_ptr, length);
return;
}
else if (png_ptr->mode & PNG_HAVE_PLTE)
{
/* Should be an error, but we can cope with it */
png_warning(png_ptr, "Out of place sBIT chunk");
}
if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT))
{
png_warning(png_ptr, "Duplicate sBIT chunk");
png_crc_finish(png_ptr, length);
return;
}
if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
truelen = 3;
else
truelen = (png_size_t)png_ptr->channels;
if (length != truelen || length > 4)
{
png_warning(png_ptr, "Incorrect sBIT chunk length");
png_crc_finish(png_ptr, length);
return;
}
png_crc_read(png_ptr, buf, truelen);
if (png_crc_finish(png_ptr, 0))
return;
if (png_ptr->color_type & PNG_COLOR_MASK_COLOR)
{
png_ptr->sig_bit.red = buf[0];
png_ptr->sig_bit.green = buf[1];
png_ptr->sig_bit.blue = buf[2];
png_ptr->sig_bit.alpha = buf[3];
}
else
{
png_ptr->sig_bit.gray = buf[0];
png_ptr->sig_bit.red = buf[0];
png_ptr->sig_bit.green = buf[0];
png_ptr->sig_bit.blue = buf[0];
png_ptr->sig_bit.alpha = buf[1];
}
png_set_sBIT(png_ptr, info_ptr, &(png_ptr->sig_bit));
}
#endif
#ifdef PNG_READ_cHRM_SUPPORTED
void /* PRIVATE */
png_handle_cHRM(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
{
png_byte buf[32];
png_fixed_point x_white, y_white, x_red, y_red, x_green, y_green, x_blue,
y_blue;
png_debug(1, "in png_handle_cHRM");
if (!(png_ptr->mode & PNG_HAVE_IHDR))
png_error(png_ptr, "Missing IHDR before cHRM");
else if (png_ptr->mode & PNG_HAVE_IDAT)
{
png_warning(png_ptr, "Invalid cHRM after IDAT");
png_crc_finish(png_ptr, length);
return;
}
else if (png_ptr->mode & PNG_HAVE_PLTE)
/* Should be an error, but we can cope with it */
png_warning(png_ptr, "Out of place cHRM chunk");
if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_cHRM)
# ifdef PNG_READ_sRGB_SUPPORTED
&& !(info_ptr->valid & PNG_INFO_sRGB)
# endif
)
{
png_warning(png_ptr, "Duplicate cHRM chunk");
png_crc_finish(png_ptr, length);
return;
}
if (length != 32)
{
png_warning(png_ptr, "Incorrect cHRM chunk length");
png_crc_finish(png_ptr, length);
return;
}
png_crc_read(png_ptr, buf, 32);
if (png_crc_finish(png_ptr, 0))
return;
x_white = png_get_fixed_point(NULL, buf);
y_white = png_get_fixed_point(NULL, buf + 4);
x_red = png_get_fixed_point(NULL, buf + 8);
y_red = png_get_fixed_point(NULL, buf + 12);
x_green = png_get_fixed_point(NULL, buf + 16);
y_green = png_get_fixed_point(NULL, buf + 20);
x_blue = png_get_fixed_point(NULL, buf + 24);
y_blue = png_get_fixed_point(NULL, buf + 28);
if (x_white == PNG_FIXED_ERROR ||
y_white == PNG_FIXED_ERROR ||
x_red == PNG_FIXED_ERROR ||
y_red == PNG_FIXED_ERROR ||
x_green == PNG_FIXED_ERROR ||
y_green == PNG_FIXED_ERROR ||
x_blue == PNG_FIXED_ERROR ||
y_blue == PNG_FIXED_ERROR)
{
png_warning(png_ptr, "Ignoring cHRM chunk with negative chromaticities");
return;
}
#ifdef PNG_READ_sRGB_SUPPORTED
if ((info_ptr != NULL) && (info_ptr->valid & PNG_INFO_sRGB))
{
if (PNG_OUT_OF_RANGE(x_white, 31270, 1000) ||
PNG_OUT_OF_RANGE(y_white, 32900, 1000) ||
PNG_OUT_OF_RANGE(x_red, 64000, 1000) ||
PNG_OUT_OF_RANGE(y_red, 33000, 1000) ||
PNG_OUT_OF_RANGE(x_green, 30000, 1000) ||
PNG_OUT_OF_RANGE(y_green, 60000, 1000) ||
PNG_OUT_OF_RANGE(x_blue, 15000, 1000) ||
PNG_OUT_OF_RANGE(y_blue, 6000, 1000))
{
PNG_WARNING_PARAMETERS(p)
png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_fixed, x_white);
png_warning_parameter_signed(p, 2, PNG_NUMBER_FORMAT_fixed, y_white);
png_warning_parameter_signed(p, 3, PNG_NUMBER_FORMAT_fixed, x_red);
png_warning_parameter_signed(p, 4, PNG_NUMBER_FORMAT_fixed, y_red);
png_warning_parameter_signed(p, 5, PNG_NUMBER_FORMAT_fixed, x_green);
png_warning_parameter_signed(p, 6, PNG_NUMBER_FORMAT_fixed, y_green);
png_warning_parameter_signed(p, 7, PNG_NUMBER_FORMAT_fixed, x_blue);
png_warning_parameter_signed(p, 8, PNG_NUMBER_FORMAT_fixed, y_blue);
png_formatted_warning(png_ptr, p,
"Ignoring incorrect cHRM white(@1,@2) r(@3,@4)g(@5,@6)b(@7,@8) "
"when sRGB is also present");
}
return;
}
#endif /* PNG_READ_sRGB_SUPPORTED */
#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
/* Store the _white values as default coefficients for the rgb to gray
* operation if it is supported. Check if the transform is already set to
* avoid destroying the transform values.
*/
if (!png_ptr->rgb_to_gray_coefficients_set)
{
/* png_set_background has not been called and we haven't seen an sRGB
* chunk yet. Find the XYZ of the three end points.
*/
png_XYZ XYZ;
png_xy xy;
xy.redx = x_red;
xy.redy = y_red;
xy.greenx = x_green;
xy.greeny = y_green;
xy.bluex = x_blue;
xy.bluey = y_blue;
xy.whitex = x_white;
xy.whitey = y_white;
if (png_XYZ_from_xy_checked(png_ptr, &XYZ, xy))
{
/* The success case, because XYZ_from_xy normalises to a reference
* white Y of 1.0 we just need to scale the numbers. This should
* always work just fine. It is an internal error if this overflows.
*/
{
png_fixed_point r, g, b;
if (png_muldiv(&r, XYZ.redY, 32768, PNG_FP_1) &&
r >= 0 && r <= 32768 &&
png_muldiv(&g, XYZ.greenY, 32768, PNG_FP_1) &&
g >= 0 && g <= 32768 &&
png_muldiv(&b, XYZ.blueY, 32768, PNG_FP_1) &&
b >= 0 && b <= 32768 &&
r+g+b <= 32769)
{
/* We allow 0 coefficients here. r+g+b may be 32769 if two or
* all of the coefficients were rounded up. Handle this by
* reducing the *largest* coefficient by 1; this matches the
* approach used for the default coefficients in pngrtran.c
*/
int add = 0;
if (r+g+b > 32768)
add = -1;
else if (r+g+b < 32768)
add = 1;
if (add != 0)
{
if (g >= r && g >= b)
g += add;
else if (r >= g && r >= b)
r += add;
else
b += add;
}
/* Check for an internal error. */
if (r+g+b != 32768)
png_error(png_ptr,
"internal error handling cHRM coefficients");
png_ptr->rgb_to_gray_red_coeff = (png_uint_16)r;
png_ptr->rgb_to_gray_green_coeff = (png_uint_16)g;
}
/* This is a png_error at present even though it could be ignored -
* it should never happen, but it is important that if it does, the
* bug is fixed.
*/
else
png_error(png_ptr, "internal error handling cHRM->XYZ");
}
}
}
#endif
png_set_cHRM_fixed(png_ptr, info_ptr, x_white, y_white, x_red, y_red,
x_green, y_green, x_blue, y_blue);
}
#endif
#ifdef PNG_READ_sRGB_SUPPORTED
void /* PRIVATE */
png_handle_sRGB(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
{
int intent;
png_byte buf[1];
png_debug(1, "in png_handle_sRGB");
if (!(png_ptr->mode & PNG_HAVE_IHDR))
png_error(png_ptr, "Missing IHDR before sRGB");
else if (png_ptr->mode & PNG_HAVE_IDAT)
{
png_warning(png_ptr, "Invalid sRGB after IDAT");
png_crc_finish(png_ptr, length);
return;
}
else if (png_ptr->mode & PNG_HAVE_PLTE)
/* Should be an error, but we can cope with it */
png_warning(png_ptr, "Out of place sRGB chunk");
if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sRGB))
{
png_warning(png_ptr, "Duplicate sRGB chunk");
png_crc_finish(png_ptr, length);
return;
}
if (length != 1)
{
png_warning(png_ptr, "Incorrect sRGB chunk length");
png_crc_finish(png_ptr, length);
return;
}
png_crc_read(png_ptr, buf, 1);
if (png_crc_finish(png_ptr, 0))
return;
intent = buf[0];
/* Check for bad intent */
if (intent >= PNG_sRGB_INTENT_LAST)
{
png_warning(png_ptr, "Unknown sRGB intent");
return;
}
#if defined(PNG_READ_gAMA_SUPPORTED) && defined(PNG_READ_GAMMA_SUPPORTED)
if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_gAMA))
{
if (PNG_OUT_OF_RANGE(info_ptr->gamma, 45500, 500))
{
PNG_WARNING_PARAMETERS(p)
png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_fixed,
info_ptr->gamma);
png_formatted_warning(png_ptr, p,
"Ignoring incorrect gAMA value @1 when sRGB is also present");
}
}
#endif /* PNG_READ_gAMA_SUPPORTED */
#ifdef PNG_READ_cHRM_SUPPORTED
if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_cHRM))
if (PNG_OUT_OF_RANGE(info_ptr->x_white, 31270, 1000) ||
PNG_OUT_OF_RANGE(info_ptr->y_white, 32900, 1000) ||
PNG_OUT_OF_RANGE(info_ptr->x_red, 64000, 1000) ||
PNG_OUT_OF_RANGE(info_ptr->y_red, 33000, 1000) ||
PNG_OUT_OF_RANGE(info_ptr->x_green, 30000, 1000) ||
PNG_OUT_OF_RANGE(info_ptr->y_green, 60000, 1000) ||
PNG_OUT_OF_RANGE(info_ptr->x_blue, 15000, 1000) ||
PNG_OUT_OF_RANGE(info_ptr->y_blue, 6000, 1000))
{
png_warning(png_ptr,
"Ignoring incorrect cHRM value when sRGB is also present");
}
#endif /* PNG_READ_cHRM_SUPPORTED */
/* This is recorded for use when handling the cHRM chunk above. An sRGB
* chunk unconditionally overwrites the coefficients for grayscale conversion
* too.
*/
png_ptr->is_sRGB = 1;
# ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
/* Don't overwrite user supplied values: */
if (!png_ptr->rgb_to_gray_coefficients_set)
{
/* These numbers come from the sRGB specification (or, since one has to
* pay much money to get a copy, the wikipedia sRGB page) the
* chromaticity values quoted have been inverted to get the reverse
* transformation from RGB to XYZ and the 'Y' coefficients scaled by
* 32768 (then rounded).
*
* sRGB and ITU Rec-709 both truncate the values for the D65 white
* point to four digits and, even though it actually stores five
* digits, the PNG spec gives the truncated value.
*
* This means that when the chromaticities are converted back to XYZ
* end points we end up with (6968,23435,2366), which, as described in
* pngrtran.c, would overflow. If the five digit precision and up is
* used we get, instead:
*
* 6968*R + 23435*G + 2365*B
*
* (Notice that this rounds the blue coefficient down, rather than the
* choice used in pngrtran.c which is to round the green one down.)
*/
png_ptr->rgb_to_gray_red_coeff = 6968; /* 0.212639005871510 */
png_ptr->rgb_to_gray_green_coeff = 23434; /* 0.715168678767756 */
/* png_ptr->rgb_to_gray_blue_coeff = 2366; 0.072192315360734 */
/* The following keeps the cHRM chunk from destroying the
* coefficients again in the event that it follows the sRGB chunk.
*/
png_ptr->rgb_to_gray_coefficients_set = 1;
}
# endif
png_set_sRGB_gAMA_and_cHRM(png_ptr, info_ptr, intent);
}
#endif /* PNG_READ_sRGB_SUPPORTED */
#ifdef PNG_READ_iCCP_SUPPORTED
void /* PRIVATE */
png_handle_iCCP(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
/* Note: this does not properly handle chunks that are > 64K under DOS */
{
png_byte compression_type;
png_bytep pC;
png_charp profile;
png_uint_32 skip = 0;
png_uint_32 profile_size;
png_alloc_size_t profile_length;
png_size_t slength, prefix_length, data_length;
png_debug(1, "in png_handle_iCCP");
if (!(png_ptr->mode & PNG_HAVE_IHDR))
png_error(png_ptr, "Missing IHDR before iCCP");
else if (png_ptr->mode & PNG_HAVE_IDAT)
{
png_warning(png_ptr, "Invalid iCCP after IDAT");
png_crc_finish(png_ptr, length);
return;
}
else if (png_ptr->mode & PNG_HAVE_PLTE)
/* Should be an error, but we can cope with it */
png_warning(png_ptr, "Out of place iCCP chunk");
if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_iCCP))
{
png_warning(png_ptr, "Duplicate iCCP chunk");
png_crc_finish(png_ptr, length);
return;
}
#ifdef PNG_MAX_MALLOC_64K
if (length > (png_uint_32)65535L)
{
png_warning(png_ptr, "iCCP chunk too large to fit in memory");
skip = length - (png_uint_32)65535L;
length = (png_uint_32)65535L;
}
#endif
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = (png_charp)png_malloc(png_ptr, length + 1);
slength = (png_size_t)length;
png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength);
if (png_crc_finish(png_ptr, skip))
{
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
return;
}
png_ptr->chunkdata[slength] = 0x00;
for (profile = png_ptr->chunkdata; *profile; profile++)
/* Empty loop to find end of name */ ;
++profile;
/* There should be at least one zero (the compression type byte)
* following the separator, and we should be on it
*/
if (profile >= png_ptr->chunkdata + slength - 1)
{
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
png_warning(png_ptr, "Malformed iCCP chunk");
return;
}
/* Compression_type should always be zero */
compression_type = *profile++;
if (compression_type)
{
png_warning(png_ptr, "Ignoring nonzero compression type in iCCP chunk");
compression_type = 0x00; /* Reset it to zero (libpng-1.0.6 through 1.0.8
wrote nonzero) */
}
prefix_length = profile - png_ptr->chunkdata;
png_decompress_chunk(png_ptr, compression_type,
slength, prefix_length, &data_length);
profile_length = data_length - prefix_length;
if (prefix_length > data_length || profile_length < 4)
{
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
png_warning(png_ptr, "Profile size field missing from iCCP chunk");
return;
}
/* Check the profile_size recorded in the first 32 bits of the ICC profile */
pC = (png_bytep)(png_ptr->chunkdata + prefix_length);
profile_size = ((*(pC )) << 24) |
((*(pC + 1)) << 16) |
((*(pC + 2)) << 8) |
((*(pC + 3)) );
/* NOTE: the following guarantees that 'profile_length' fits into 32 bits,
* because profile_size is a 32 bit value.
*/
if (profile_size < profile_length)
profile_length = profile_size;
/* And the following guarantees that profile_size == profile_length. */
if (profile_size > profile_length)
{
PNG_WARNING_PARAMETERS(p)
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
png_warning_parameter_unsigned(p, 1, PNG_NUMBER_FORMAT_u, profile_size);
png_warning_parameter_unsigned(p, 2, PNG_NUMBER_FORMAT_u, profile_length);
png_formatted_warning(png_ptr, p,
"Ignoring iCCP chunk with declared size = @1 and actual length = @2");
return;
}
png_set_iCCP(png_ptr, info_ptr, png_ptr->chunkdata,
compression_type, (png_bytep)png_ptr->chunkdata + prefix_length,
profile_size);
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
}
#endif /* PNG_READ_iCCP_SUPPORTED */
#ifdef PNG_READ_sPLT_SUPPORTED
void /* PRIVATE */
png_handle_sPLT(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
/* Note: this does not properly handle chunks that are > 64K under DOS */
{
png_bytep entry_start;
png_sPLT_t new_palette;
png_sPLT_entryp pp;
png_uint_32 data_length;
int entry_size, i;
png_uint_32 skip = 0;
png_size_t slength;
png_uint_32 dl;
png_size_t max_dl;
png_debug(1, "in png_handle_sPLT");
#ifdef PNG_USER_LIMITS_SUPPORTED
if (png_ptr->user_chunk_cache_max != 0)
{
if (png_ptr->user_chunk_cache_max == 1)
{
png_crc_finish(png_ptr, length);
return;
}
if (--png_ptr->user_chunk_cache_max == 1)
{
png_warning(png_ptr, "No space in chunk cache for sPLT");
png_crc_finish(png_ptr, length);
return;
}
}
#endif
if (!(png_ptr->mode & PNG_HAVE_IHDR))
png_error(png_ptr, "Missing IHDR before sPLT");
else if (png_ptr->mode & PNG_HAVE_IDAT)
{
png_warning(png_ptr, "Invalid sPLT after IDAT");
png_crc_finish(png_ptr, length);
return;
}
#ifdef PNG_MAX_MALLOC_64K
if (length > (png_uint_32)65535L)
{
png_warning(png_ptr, "sPLT chunk too large to fit in memory");
skip = length - (png_uint_32)65535L;
length = (png_uint_32)65535L;
}
#endif
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = (png_charp)png_malloc(png_ptr, length + 1);
/* WARNING: this may break if size_t is less than 32 bits; it is assumed
* that the PNG_MAX_MALLOC_64K test is enabled in this case, but this is a
* potential breakage point if the types in pngconf.h aren't exactly right.
*/
slength = (png_size_t)length;
png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength);
if (png_crc_finish(png_ptr, skip))
{
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
return;
}
png_ptr->chunkdata[slength] = 0x00;
for (entry_start = (png_bytep)png_ptr->chunkdata; *entry_start;
entry_start++)
/* Empty loop to find end of name */ ;
++entry_start;
/* A sample depth should follow the separator, and we should be on it */
if (entry_start > (png_bytep)png_ptr->chunkdata + slength - 2)
{
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
png_warning(png_ptr, "malformed sPLT chunk");
return;
}
new_palette.depth = *entry_start++;
entry_size = (new_palette.depth == 8 ? 6 : 10);
/* This must fit in a png_uint_32 because it is derived from the original
* chunk data length (and use 'length', not 'slength' here for clarity -
* they are guaranteed to be the same, see the tests above.)
*/
data_length = length - (png_uint_32)(entry_start -
(png_bytep)png_ptr->chunkdata);
/* Integrity-check the data length */
if (data_length % entry_size)
{
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
png_warning(png_ptr, "sPLT chunk has bad length");
return;
}
dl = (png_int_32)(data_length / entry_size);
max_dl = PNG_SIZE_MAX / png_sizeof(png_sPLT_entry);
if (dl > max_dl)
{
png_warning(png_ptr, "sPLT chunk too long");
return;
}
new_palette.nentries = (png_int_32)(data_length / entry_size);
new_palette.entries = (png_sPLT_entryp)png_malloc_warn(
png_ptr, new_palette.nentries * png_sizeof(png_sPLT_entry));
if (new_palette.entries == NULL)
{
png_warning(png_ptr, "sPLT chunk requires too much memory");
return;
}
#ifdef PNG_POINTER_INDEXING_SUPPORTED
for (i = 0; i < new_palette.nentries; i++)
{
pp = new_palette.entries + i;
if (new_palette.depth == 8)
{
pp->red = *entry_start++;
pp->green = *entry_start++;
pp->blue = *entry_start++;
pp->alpha = *entry_start++;
}
else
{
pp->red = png_get_uint_16(entry_start); entry_start += 2;
pp->green = png_get_uint_16(entry_start); entry_start += 2;
pp->blue = png_get_uint_16(entry_start); entry_start += 2;
pp->alpha = png_get_uint_16(entry_start); entry_start += 2;
}
pp->frequency = png_get_uint_16(entry_start); entry_start += 2;
}
#else
pp = new_palette.entries;
for (i = 0; i < new_palette.nentries; i++)
{
if (new_palette.depth == 8)
{
pp[i].red = *entry_start++;
pp[i].green = *entry_start++;
pp[i].blue = *entry_start++;
pp[i].alpha = *entry_start++;
}
else
{
pp[i].red = png_get_uint_16(entry_start); entry_start += 2;
pp[i].green = png_get_uint_16(entry_start); entry_start += 2;
pp[i].blue = png_get_uint_16(entry_start); entry_start += 2;
pp[i].alpha = png_get_uint_16(entry_start); entry_start += 2;
}
pp[i].frequency = png_get_uint_16(entry_start); entry_start += 2;
}
#endif
/* Discard all chunk data except the name and stash that */
new_palette.name = png_ptr->chunkdata;
png_set_sPLT(png_ptr, info_ptr, &new_palette, 1);
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
png_free(png_ptr, new_palette.entries);
}
#endif /* PNG_READ_sPLT_SUPPORTED */
#ifdef PNG_READ_tRNS_SUPPORTED
void /* PRIVATE */
png_handle_tRNS(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
{
png_byte readbuf[PNG_MAX_PALETTE_LENGTH];
png_debug(1, "in png_handle_tRNS");
if (!(png_ptr->mode & PNG_HAVE_IHDR))
png_error(png_ptr, "Missing IHDR before tRNS");
else if (png_ptr->mode & PNG_HAVE_IDAT)
{
png_warning(png_ptr, "Invalid tRNS after IDAT");
png_crc_finish(png_ptr, length);
return;
}
else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS))
{
png_warning(png_ptr, "Duplicate tRNS chunk");
png_crc_finish(png_ptr, length);
return;
}
if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
{
png_byte buf[2];
if (length != 2)
{
png_warning(png_ptr, "Incorrect tRNS chunk length");
png_crc_finish(png_ptr, length);
return;
}
png_crc_read(png_ptr, buf, 2);
png_ptr->num_trans = 1;
png_ptr->trans_color.gray = png_get_uint_16(buf);
}
else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
{
png_byte buf[6];
if (length != 6)
{
png_warning(png_ptr, "Incorrect tRNS chunk length");
png_crc_finish(png_ptr, length);
return;
}
png_crc_read(png_ptr, buf, (png_size_t)length);
png_ptr->num_trans = 1;
png_ptr->trans_color.red = png_get_uint_16(buf);
png_ptr->trans_color.green = png_get_uint_16(buf + 2);
png_ptr->trans_color.blue = png_get_uint_16(buf + 4);
}
else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
{
if (!(png_ptr->mode & PNG_HAVE_PLTE))
{
/* Should be an error, but we can cope with it. */
png_warning(png_ptr, "Missing PLTE before tRNS");
}
if (length > (png_uint_32)png_ptr->num_palette ||
length > PNG_MAX_PALETTE_LENGTH)
{
png_warning(png_ptr, "Incorrect tRNS chunk length");
png_crc_finish(png_ptr, length);
return;
}
if (length == 0)
{
png_warning(png_ptr, "Zero length tRNS chunk");
png_crc_finish(png_ptr, length);
return;
}
png_crc_read(png_ptr, readbuf, (png_size_t)length);
png_ptr->num_trans = (png_uint_16)length;
}
else
{
png_warning(png_ptr, "tRNS chunk not allowed with alpha channel");
png_crc_finish(png_ptr, length);
return;
}
if (png_crc_finish(png_ptr, 0))
{
png_ptr->num_trans = 0;
return;
}
png_set_tRNS(png_ptr, info_ptr, readbuf, png_ptr->num_trans,
&(png_ptr->trans_color));
}
#endif
#ifdef PNG_READ_bKGD_SUPPORTED
void /* PRIVATE */
png_handle_bKGD(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
{
png_size_t truelen;
png_byte buf[6];
png_color_16 background;
png_debug(1, "in png_handle_bKGD");
if (!(png_ptr->mode & PNG_HAVE_IHDR))
png_error(png_ptr, "Missing IHDR before bKGD");
else if (png_ptr->mode & PNG_HAVE_IDAT)
{
png_warning(png_ptr, "Invalid bKGD after IDAT");
png_crc_finish(png_ptr, length);
return;
}
else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
!(png_ptr->mode & PNG_HAVE_PLTE))
{
png_warning(png_ptr, "Missing PLTE before bKGD");
png_crc_finish(png_ptr, length);
return;
}
else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD))
{
png_warning(png_ptr, "Duplicate bKGD chunk");
png_crc_finish(png_ptr, length);
return;
}
if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
truelen = 1;
else if (png_ptr->color_type & PNG_COLOR_MASK_COLOR)
truelen = 6;
else
truelen = 2;
if (length != truelen)
{
png_warning(png_ptr, "Incorrect bKGD chunk length");
png_crc_finish(png_ptr, length);
return;
}
png_crc_read(png_ptr, buf, truelen);
if (png_crc_finish(png_ptr, 0))
return;
/* We convert the index value into RGB components so that we can allow
* arbitrary RGB values for background when we have transparency, and
* so it is easy to determine the RGB values of the background color
* from the info_ptr struct.
*/
if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
{
background.index = buf[0];
if (info_ptr && info_ptr->num_palette)
{
if (buf[0] >= info_ptr->num_palette)
{
png_warning(png_ptr, "Incorrect bKGD chunk index value");
return;
}
background.red = (png_uint_16)png_ptr->palette[buf[0]].red;
background.green = (png_uint_16)png_ptr->palette[buf[0]].green;
background.blue = (png_uint_16)png_ptr->palette[buf[0]].blue;
}
else
background.red = background.green = background.blue = 0;
background.gray = 0;
}
else if (!(png_ptr->color_type & PNG_COLOR_MASK_COLOR)) /* GRAY */
{
background.index = 0;
background.red =
background.green =
background.blue =
background.gray = png_get_uint_16(buf);
}
else
{
background.index = 0;
background.red = png_get_uint_16(buf);
background.green = png_get_uint_16(buf + 2);
background.blue = png_get_uint_16(buf + 4);
background.gray = 0;
}
png_set_bKGD(png_ptr, info_ptr, &background);
}
#endif
#ifdef PNG_READ_hIST_SUPPORTED
void /* PRIVATE */
png_handle_hIST(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
{
unsigned int num, i;
png_uint_16 readbuf[PNG_MAX_PALETTE_LENGTH];
png_debug(1, "in png_handle_hIST");
if (!(png_ptr->mode & PNG_HAVE_IHDR))
png_error(png_ptr, "Missing IHDR before hIST");
else if (png_ptr->mode & PNG_HAVE_IDAT)
{
png_warning(png_ptr, "Invalid hIST after IDAT");
png_crc_finish(png_ptr, length);
return;
}
else if (!(png_ptr->mode & PNG_HAVE_PLTE))
{
png_warning(png_ptr, "Missing PLTE before hIST");
png_crc_finish(png_ptr, length);
return;
}
else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST))
{
png_warning(png_ptr, "Duplicate hIST chunk");
png_crc_finish(png_ptr, length);
return;
}
num = length / 2 ;
if (num != (unsigned int)png_ptr->num_palette || num >
(unsigned int)PNG_MAX_PALETTE_LENGTH)
{
png_warning(png_ptr, "Incorrect hIST chunk length");
png_crc_finish(png_ptr, length);
return;
}
for (i = 0; i < num; i++)
{
png_byte buf[2];
png_crc_read(png_ptr, buf, 2);
readbuf[i] = png_get_uint_16(buf);
}
if (png_crc_finish(png_ptr, 0))
return;
png_set_hIST(png_ptr, info_ptr, readbuf);
}
#endif
#ifdef PNG_READ_pHYs_SUPPORTED
void /* PRIVATE */
png_handle_pHYs(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
{
png_byte buf[9];
png_uint_32 res_x, res_y;
int unit_type;
png_debug(1, "in png_handle_pHYs");
if (!(png_ptr->mode & PNG_HAVE_IHDR))
png_error(png_ptr, "Missing IHDR before pHYs");
else if (png_ptr->mode & PNG_HAVE_IDAT)
{
png_warning(png_ptr, "Invalid pHYs after IDAT");
png_crc_finish(png_ptr, length);
return;
}
else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
{
png_warning(png_ptr, "Duplicate pHYs chunk");
png_crc_finish(png_ptr, length);
return;
}
if (length != 9)
{
png_warning(png_ptr, "Incorrect pHYs chunk length");
png_crc_finish(png_ptr, length);
return;
}
png_crc_read(png_ptr, buf, 9);
if (png_crc_finish(png_ptr, 0))
return;
res_x = png_get_uint_32(buf);
res_y = png_get_uint_32(buf + 4);
unit_type = buf[8];
png_set_pHYs(png_ptr, info_ptr, res_x, res_y, unit_type);
}
#endif
#ifdef PNG_READ_oFFs_SUPPORTED
void /* PRIVATE */
png_handle_oFFs(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
{
png_byte buf[9];
png_int_32 offset_x, offset_y;
int unit_type;
png_debug(1, "in png_handle_oFFs");
if (!(png_ptr->mode & PNG_HAVE_IHDR))
png_error(png_ptr, "Missing IHDR before oFFs");
else if (png_ptr->mode & PNG_HAVE_IDAT)
{
png_warning(png_ptr, "Invalid oFFs after IDAT");
png_crc_finish(png_ptr, length);
return;
}
else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs))
{
png_warning(png_ptr, "Duplicate oFFs chunk");
png_crc_finish(png_ptr, length);
return;
}
if (length != 9)
{
png_warning(png_ptr, "Incorrect oFFs chunk length");
png_crc_finish(png_ptr, length);
return;
}
png_crc_read(png_ptr, buf, 9);
if (png_crc_finish(png_ptr, 0))
return;
offset_x = png_get_int_32(buf);
offset_y = png_get_int_32(buf + 4);
unit_type = buf[8];
png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y, unit_type);
}
#endif
#ifdef PNG_READ_pCAL_SUPPORTED
/* Read the pCAL chunk (described in the PNG Extensions document) */
void /* PRIVATE */
png_handle_pCAL(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
{
png_int_32 X0, X1;
png_byte type, nparams;
png_charp buf, units, endptr;
png_charpp params;
png_size_t slength;
int i;
png_debug(1, "in png_handle_pCAL");
if (!(png_ptr->mode & PNG_HAVE_IHDR))
png_error(png_ptr, "Missing IHDR before pCAL");
else if (png_ptr->mode & PNG_HAVE_IDAT)
{
png_warning(png_ptr, "Invalid pCAL after IDAT");
png_crc_finish(png_ptr, length);
return;
}
else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL))
{
png_warning(png_ptr, "Duplicate pCAL chunk");
png_crc_finish(png_ptr, length);
return;
}
png_debug1(2, "Allocating and reading pCAL chunk data (%u bytes)",
length + 1);
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = (png_charp)png_malloc_warn(png_ptr, length + 1);
if (png_ptr->chunkdata == NULL)
{
png_warning(png_ptr, "No memory for pCAL purpose");
return;
}
slength = (png_size_t)length;
png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength);
if (png_crc_finish(png_ptr, 0))
{
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
return;
}
png_ptr->chunkdata[slength] = 0x00; /* Null terminate the last string */
png_debug(3, "Finding end of pCAL purpose string");
for (buf = png_ptr->chunkdata; *buf; buf++)
/* Empty loop */ ;
endptr = png_ptr->chunkdata + slength;
/* We need to have at least 12 bytes after the purpose string
* in order to get the parameter information.
*/
if (endptr <= buf + 12)
{
png_warning(png_ptr, "Invalid pCAL data");
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
return;
}
png_debug(3, "Reading pCAL X0, X1, type, nparams, and units");
X0 = png_get_int_32((png_bytep)buf+1);
X1 = png_get_int_32((png_bytep)buf+5);
type = buf[9];
nparams = buf[10];
units = buf + 11;
png_debug(3, "Checking pCAL equation type and number of parameters");
/* Check that we have the right number of parameters for known
* equation types.
*/
if ((type == PNG_EQUATION_LINEAR && nparams != 2) ||
(type == PNG_EQUATION_BASE_E && nparams != 3) ||
(type == PNG_EQUATION_ARBITRARY && nparams != 3) ||
(type == PNG_EQUATION_HYPERBOLIC && nparams != 4))
{
png_warning(png_ptr, "Invalid pCAL parameters for equation type");
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
return;
}
else if (type >= PNG_EQUATION_LAST)
{
png_warning(png_ptr, "Unrecognized equation type for pCAL chunk");
}
for (buf = units; *buf; buf++)
/* Empty loop to move past the units string. */ ;
png_debug(3, "Allocating pCAL parameters array");
params = (png_charpp)png_malloc_warn(png_ptr,
(png_size_t)(nparams * png_sizeof(png_charp)));
if (params == NULL)
{
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
png_warning(png_ptr, "No memory for pCAL params");
return;
}
/* Get pointers to the start of each parameter string. */
for (i = 0; i < (int)nparams; i++)
{
buf++; /* Skip the null string terminator from previous parameter. */
png_debug1(3, "Reading pCAL parameter %d", i);
for (params[i] = buf; buf <= endptr && *buf != 0x00; buf++)
/* Empty loop to move past each parameter string */ ;
/* Make sure we haven't run out of data yet */
if (buf > endptr)
{
png_warning(png_ptr, "Invalid pCAL data");
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
png_free(png_ptr, params);
return;
}
}
png_set_pCAL(png_ptr, info_ptr, png_ptr->chunkdata, X0, X1, type, nparams,
units, params);
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
png_free(png_ptr, params);
}
#endif
#ifdef PNG_READ_sCAL_SUPPORTED
/* Read the sCAL chunk */
void /* PRIVATE */
png_handle_sCAL(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
{
png_size_t slength, i;
int state;
png_debug(1, "in png_handle_sCAL");
if (!(png_ptr->mode & PNG_HAVE_IHDR))
png_error(png_ptr, "Missing IHDR before sCAL");
else if (png_ptr->mode & PNG_HAVE_IDAT)
{
png_warning(png_ptr, "Invalid sCAL after IDAT");
png_crc_finish(png_ptr, length);
return;
}
else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sCAL))
{
png_warning(png_ptr, "Duplicate sCAL chunk");
png_crc_finish(png_ptr, length);
return;
}
/* Need unit type, width, \0, height: minimum 4 bytes */
else if (length < 4)
{
png_warning(png_ptr, "sCAL chunk too short");
png_crc_finish(png_ptr, length);
return;
}
png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)",
length + 1);
png_ptr->chunkdata = (png_charp)png_malloc_warn(png_ptr, length + 1);
if (png_ptr->chunkdata == NULL)
{
png_warning(png_ptr, "Out of memory while processing sCAL chunk");
png_crc_finish(png_ptr, length);
return;
}
slength = (png_size_t)length;
png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength);
png_ptr->chunkdata[slength] = 0x00; /* Null terminate the last string */
if (png_crc_finish(png_ptr, 0))
{
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
return;
}
/* Validate the unit. */
if (png_ptr->chunkdata[0] != 1 && png_ptr->chunkdata[0] != 2)
{
png_warning(png_ptr, "Invalid sCAL ignored: invalid unit");
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
return;
}
/* Validate the ASCII numbers, need two ASCII numbers separated by
* a '\0' and they need to fit exactly in the chunk data.
*/
i = 1;
state = 0;
if (!png_check_fp_number(png_ptr->chunkdata, slength, &state, &i) ||
i >= slength || png_ptr->chunkdata[i++] != 0)
png_warning(png_ptr, "Invalid sCAL chunk ignored: bad width format");
else if (!PNG_FP_IS_POSITIVE(state))
png_warning(png_ptr, "Invalid sCAL chunk ignored: non-positive width");
else
{
png_size_t heighti = i;
state = 0;
if (!png_check_fp_number(png_ptr->chunkdata, slength, &state, &i) ||
i != slength)
png_warning(png_ptr, "Invalid sCAL chunk ignored: bad height format");
else if (!PNG_FP_IS_POSITIVE(state))
png_warning(png_ptr,
"Invalid sCAL chunk ignored: non-positive height");
else
/* This is the (only) success case. */
png_set_sCAL_s(png_ptr, info_ptr, png_ptr->chunkdata[0],
png_ptr->chunkdata+1, png_ptr->chunkdata+heighti);
}
/* Clean up - just free the temporarily allocated buffer. */
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
}
#endif
#ifdef PNG_READ_tIME_SUPPORTED
void /* PRIVATE */
png_handle_tIME(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
{
png_byte buf[7];
png_time mod_time;
png_debug(1, "in png_handle_tIME");
if (!(png_ptr->mode & PNG_HAVE_IHDR))
png_error(png_ptr, "Out of place tIME chunk");
else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME))
{
png_warning(png_ptr, "Duplicate tIME chunk");
png_crc_finish(png_ptr, length);
return;
}
if (png_ptr->mode & PNG_HAVE_IDAT)
png_ptr->mode |= PNG_AFTER_IDAT;
if (length != 7)
{
png_warning(png_ptr, "Incorrect tIME chunk length");
png_crc_finish(png_ptr, length);
return;
}
png_crc_read(png_ptr, buf, 7);
if (png_crc_finish(png_ptr, 0))
return;
mod_time.second = buf[6];
mod_time.minute = buf[5];
mod_time.hour = buf[4];
mod_time.day = buf[3];
mod_time.month = buf[2];
mod_time.year = png_get_uint_16(buf);
png_set_tIME(png_ptr, info_ptr, &mod_time);
}
#endif
#ifdef PNG_READ_tEXt_SUPPORTED
/* Note: this does not properly handle chunks that are > 64K under DOS */
void /* PRIVATE */
png_handle_tEXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
{
png_textp text_ptr;
png_charp key;
png_charp text;
png_uint_32 skip = 0;
png_size_t slength;
int ret;
png_debug(1, "in png_handle_tEXt");
#ifdef PNG_USER_LIMITS_SUPPORTED
if (png_ptr->user_chunk_cache_max != 0)
{
if (png_ptr->user_chunk_cache_max == 1)
{
png_crc_finish(png_ptr, length);
return;
}
if (--png_ptr->user_chunk_cache_max == 1)
{
png_warning(png_ptr, "No space in chunk cache for tEXt");
png_crc_finish(png_ptr, length);
return;
}
}
#endif
if (!(png_ptr->mode & PNG_HAVE_IHDR))
png_error(png_ptr, "Missing IHDR before tEXt");
if (png_ptr->mode & PNG_HAVE_IDAT)
png_ptr->mode |= PNG_AFTER_IDAT;
#ifdef PNG_MAX_MALLOC_64K
if (length > (png_uint_32)65535L)
{
png_warning(png_ptr, "tEXt chunk too large to fit in memory");
skip = length - (png_uint_32)65535L;
length = (png_uint_32)65535L;
}
#endif
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = (png_charp)png_malloc_warn(png_ptr, length + 1);
if (png_ptr->chunkdata == NULL)
{
png_warning(png_ptr, "No memory to process text chunk");
return;
}
slength = (png_size_t)length;
png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength);
if (png_crc_finish(png_ptr, skip))
{
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
return;
}
key = png_ptr->chunkdata;
key[slength] = 0x00;
for (text = key; *text; text++)
/* Empty loop to find end of key */ ;
if (text != key + slength)
text++;
text_ptr = (png_textp)png_malloc_warn(png_ptr,
png_sizeof(png_text));
if (text_ptr == NULL)
{
png_warning(png_ptr, "Not enough memory to process text chunk");
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
return;
}
text_ptr->compression = PNG_TEXT_COMPRESSION_NONE;
text_ptr->key = key;
text_ptr->lang = NULL;
text_ptr->lang_key = NULL;
text_ptr->itxt_length = 0;
text_ptr->text = text;
text_ptr->text_length = png_strlen(text);
ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
png_free(png_ptr, text_ptr);
if (ret)
png_warning(png_ptr, "Insufficient memory to process text chunk");
}
#endif
#ifdef PNG_READ_zTXt_SUPPORTED
/* Note: this does not correctly handle chunks that are > 64K under DOS */
void /* PRIVATE */
png_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
{
png_textp text_ptr;
png_charp text;
int comp_type;
int ret;
png_size_t slength, prefix_len, data_len;
png_debug(1, "in png_handle_zTXt");
#ifdef PNG_USER_LIMITS_SUPPORTED
if (png_ptr->user_chunk_cache_max != 0)
{
if (png_ptr->user_chunk_cache_max == 1)
{
png_crc_finish(png_ptr, length);
return;
}
if (--png_ptr->user_chunk_cache_max == 1)
{
png_warning(png_ptr, "No space in chunk cache for zTXt");
png_crc_finish(png_ptr, length);
return;
}
}
#endif
if (!(png_ptr->mode & PNG_HAVE_IHDR))
png_error(png_ptr, "Missing IHDR before zTXt");
if (png_ptr->mode & PNG_HAVE_IDAT)
png_ptr->mode |= PNG_AFTER_IDAT;
#ifdef PNG_MAX_MALLOC_64K
/* We will no doubt have problems with chunks even half this size, but
* there is no hard and fast rule to tell us where to stop.
*/
if (length > (png_uint_32)65535L)
{
png_warning(png_ptr, "zTXt chunk too large to fit in memory");
png_crc_finish(png_ptr, length);
return;
}
#endif
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = (png_charp)png_malloc_warn(png_ptr, length + 1);
if (png_ptr->chunkdata == NULL)
{
png_warning(png_ptr, "Out of memory processing zTXt chunk");
return;
}
slength = (png_size_t)length;
png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength);
if (png_crc_finish(png_ptr, 0))
{
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
return;
}
png_ptr->chunkdata[slength] = 0x00;
for (text = png_ptr->chunkdata; *text; text++)
/* Empty loop */ ;
/* zTXt must have some text after the chunkdataword */
if (text >= png_ptr->chunkdata + slength - 2)
{
png_warning(png_ptr, "Truncated zTXt chunk");
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
return;
}
else
{
comp_type = *(++text);
if (comp_type != PNG_TEXT_COMPRESSION_zTXt)
{
png_warning(png_ptr, "Unknown compression type in zTXt chunk");
comp_type = PNG_TEXT_COMPRESSION_zTXt;
}
text++; /* Skip the compression_method byte */
}
prefix_len = text - png_ptr->chunkdata;
png_decompress_chunk(png_ptr, comp_type,
(png_size_t)length, prefix_len, &data_len);
text_ptr = (png_textp)png_malloc_warn(png_ptr,
png_sizeof(png_text));
if (text_ptr == NULL)
{
png_warning(png_ptr, "Not enough memory to process zTXt chunk");
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
return;
}
text_ptr->compression = comp_type;
text_ptr->key = png_ptr->chunkdata;
text_ptr->lang = NULL;
text_ptr->lang_key = NULL;
text_ptr->itxt_length = 0;
text_ptr->text = png_ptr->chunkdata + prefix_len;
text_ptr->text_length = data_len;
ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
png_free(png_ptr, text_ptr);
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
if (ret)
png_error(png_ptr, "Insufficient memory to store zTXt chunk");
}
#endif
#ifdef PNG_READ_iTXt_SUPPORTED
/* Note: this does not correctly handle chunks that are > 64K under DOS */
void /* PRIVATE */
png_handle_iTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
{
png_textp text_ptr;
png_charp key, lang, text, lang_key;
int comp_flag;
int comp_type = 0;
int ret;
png_size_t slength, prefix_len, data_len;
png_debug(1, "in png_handle_iTXt");
#ifdef PNG_USER_LIMITS_SUPPORTED
if (png_ptr->user_chunk_cache_max != 0)
{
if (png_ptr->user_chunk_cache_max == 1)
{
png_crc_finish(png_ptr, length);
return;
}
if (--png_ptr->user_chunk_cache_max == 1)
{
png_warning(png_ptr, "No space in chunk cache for iTXt");
png_crc_finish(png_ptr, length);
return;
}
}
#endif
if (!(png_ptr->mode & PNG_HAVE_IHDR))
png_error(png_ptr, "Missing IHDR before iTXt");
if (png_ptr->mode & PNG_HAVE_IDAT)
png_ptr->mode |= PNG_AFTER_IDAT;
#ifdef PNG_MAX_MALLOC_64K
/* We will no doubt have problems with chunks even half this size, but
* there is no hard and fast rule to tell us where to stop.
*/
if (length > (png_uint_32)65535L)
{
png_warning(png_ptr, "iTXt chunk too large to fit in memory");
png_crc_finish(png_ptr, length);
return;
}
#endif
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = (png_charp)png_malloc_warn(png_ptr, length + 1);
if (png_ptr->chunkdata == NULL)
{
png_warning(png_ptr, "No memory to process iTXt chunk");
return;
}
slength = (png_size_t)length;
png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength);
if (png_crc_finish(png_ptr, 0))
{
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
return;
}
png_ptr->chunkdata[slength] = 0x00;
for (lang = png_ptr->chunkdata; *lang; lang++)
/* Empty loop */ ;
lang++; /* Skip NUL separator */
/* iTXt must have a language tag (possibly empty), two compression bytes,
* translated keyword (possibly empty), and possibly some text after the
* keyword
*/
if (lang >= png_ptr->chunkdata + slength - 3)
{
png_warning(png_ptr, "Truncated iTXt chunk");
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
return;
}
else
{
comp_flag = *lang++;
comp_type = *lang++;
}
for (lang_key = lang; *lang_key; lang_key++)
/* Empty loop */ ;
lang_key++; /* Skip NUL separator */
if (lang_key >= png_ptr->chunkdata + slength)
{
png_warning(png_ptr, "Truncated iTXt chunk");
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
return;
}
for (text = lang_key; *text; text++)
/* Empty loop */ ;
text++; /* Skip NUL separator */
if (text >= png_ptr->chunkdata + slength)
{
png_warning(png_ptr, "Malformed iTXt chunk");
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
return;
}
prefix_len = text - png_ptr->chunkdata;
key=png_ptr->chunkdata;
if (comp_flag)
png_decompress_chunk(png_ptr, comp_type,
(size_t)length, prefix_len, &data_len);
else
data_len = png_strlen(png_ptr->chunkdata + prefix_len);
text_ptr = (png_textp)png_malloc_warn(png_ptr,
png_sizeof(png_text));
if (text_ptr == NULL)
{
png_warning(png_ptr, "Not enough memory to process iTXt chunk");
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
return;
}
text_ptr->compression = (int)comp_flag + 1;
text_ptr->lang_key = png_ptr->chunkdata + (lang_key - key);
text_ptr->lang = png_ptr->chunkdata + (lang - key);
text_ptr->itxt_length = data_len;
text_ptr->text_length = 0;
text_ptr->key = png_ptr->chunkdata;
text_ptr->text = png_ptr->chunkdata + prefix_len;
ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
png_free(png_ptr, text_ptr);
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
if (ret)
png_error(png_ptr, "Insufficient memory to store iTXt chunk");
}
#endif
/* This function is called when we haven't found a handler for a
* chunk. If there isn't a problem with the chunk itself (ie bad
* chunk name, CRC, or a critical chunk), the chunk is silently ignored
* -- unless the PNG_FLAG_UNKNOWN_CHUNKS_SUPPORTED flag is on in which
* case it will be saved away to be written out later.
*/
void /* PRIVATE */
png_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
{
png_uint_32 skip = 0;
png_debug(1, "in png_handle_unknown");
#ifdef PNG_USER_LIMITS_SUPPORTED
if (png_ptr->user_chunk_cache_max != 0)
{
if (png_ptr->user_chunk_cache_max == 1)
{
png_crc_finish(png_ptr, length);
return;
}
if (--png_ptr->user_chunk_cache_max == 1)
{
png_warning(png_ptr, "No space in chunk cache for unknown chunk");
png_crc_finish(png_ptr, length);
return;
}
}
#endif
if (png_ptr->mode & PNG_HAVE_IDAT)
{
if (png_ptr->chunk_name != png_IDAT)
png_ptr->mode |= PNG_AFTER_IDAT;
}
if (PNG_CHUNK_CRITICAL(png_ptr->chunk_name))
{
#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
if (png_chunk_unknown_handling(png_ptr, png_ptr->chunk_name) !=
PNG_HANDLE_CHUNK_ALWAYS
#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
&& png_ptr->read_user_chunk_fn == NULL
#endif
)
#endif
png_chunk_error(png_ptr, "unknown critical chunk");
}
#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
if ((png_ptr->flags & PNG_FLAG_KEEP_UNKNOWN_CHUNKS)
#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
|| (png_ptr->read_user_chunk_fn != NULL)
#endif
)
{
#ifdef PNG_MAX_MALLOC_64K
if (length > 65535)
{
png_warning(png_ptr, "unknown chunk too large to fit in memory");
skip = length - 65535;
length = 65535;
}
#endif
/* TODO: this code is very close to the unknown handling in pngpread.c,
* maybe it can be put into a common utility routine?
* png_struct::unknown_chunk is just used as a temporary variable, along
* with the data into which the chunk is read. These can be eliminated.
*/
PNG_CSTRING_FROM_CHUNK(png_ptr->unknown_chunk.name, png_ptr->chunk_name);
png_ptr->unknown_chunk.size = (png_size_t)length;
if (length == 0)
png_ptr->unknown_chunk.data = NULL;
else
{
png_ptr->unknown_chunk.data = (png_bytep)png_malloc(png_ptr, length);
png_crc_read(png_ptr, png_ptr->unknown_chunk.data, length);
}
#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
if (png_ptr->read_user_chunk_fn != NULL)
{
/* Callback to user unknown chunk handler */
int ret;
ret = (*(png_ptr->read_user_chunk_fn))
(png_ptr, &png_ptr->unknown_chunk);
if (ret < 0)
png_chunk_error(png_ptr, "error in user chunk");
if (ret == 0)
{
if (PNG_CHUNK_CRITICAL(png_ptr->chunk_name))
{
#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
if (png_chunk_unknown_handling(png_ptr, png_ptr->chunk_name) !=
PNG_HANDLE_CHUNK_ALWAYS)
#endif
png_chunk_error(png_ptr, "unknown critical chunk");
}
png_set_unknown_chunks(png_ptr, info_ptr,
&png_ptr->unknown_chunk, 1);
}
}
else
#endif
png_set_unknown_chunks(png_ptr, info_ptr, &png_ptr->unknown_chunk, 1);
png_free(png_ptr, png_ptr->unknown_chunk.data);
png_ptr->unknown_chunk.data = NULL;
}
else
#endif
skip = length;
png_crc_finish(png_ptr, skip);
#ifndef PNG_READ_USER_CHUNKS_SUPPORTED
PNG_UNUSED(info_ptr) /* Quiet compiler warnings about unused info_ptr */
#endif
}
/* This function is called to verify that a chunk name is valid.
* This function can't have the "critical chunk check" incorporated
* into it, since in the future we will need to be able to call user
* functions to handle unknown critical chunks after we check that
* the chunk name itself is valid.
*/
/* Bit hacking: the test for an invalid byte in the 4 byte chunk name is:
*
* ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
*/
void /* PRIVATE */
png_check_chunk_name(png_structp png_ptr, png_uint_32 chunk_name)
{
int i;
png_debug(1, "in png_check_chunk_name");
for (i=1; i<=4; ++i)
{
int c = chunk_name & 0xff;
if (c < 65 || c > 122 || (c > 90 && c < 97))
png_chunk_error(png_ptr, "invalid chunk type");
chunk_name >>= 8;
}
}
/* Combines the row recently read in with the existing pixels in the
* row. This routine takes care of alpha and transparency if requested.
* This routine also handles the two methods of progressive display
* of interlaced images, depending on the mask value.
* The mask value describes which pixels are to be combined with
* the row. The pattern always repeats every 8 pixels, so just 8
* bits are needed. A one indicates the pixel is to be combined,
* a zero indicates the pixel is to be skipped. This is in addition
* to any alpha or transparency value associated with the pixel. If
* you want all pixels to be combined, pass 0xff (255) in mask.
*/
void /* PRIVATE */
png_combine_row(png_structp png_ptr, png_bytep dp, int display)
{
unsigned int pixel_depth = png_ptr->transformed_pixel_depth;
png_const_bytep sp = png_ptr->row_buf + 1;
png_uint_32 row_width = png_ptr->width;
unsigned int pass = png_ptr->pass;
png_bytep end_ptr = 0;
png_byte end_byte = 0;
unsigned int end_mask;
png_debug(1, "in png_combine_row");
/* Added in 1.5.6: it should not be possible to enter this routine until at
* least one row has been read from the PNG data and transformed.
*/
if (pixel_depth == 0)
png_error(png_ptr, "internal row logic error");
/* Added in 1.5.4: the pixel depth should match the information returned by
* any call to png_read_update_info at this point. Do not continue if we got
* this wrong.
*/
if (png_ptr->info_rowbytes != 0 && png_ptr->info_rowbytes !=
PNG_ROWBYTES(pixel_depth, row_width))
png_error(png_ptr, "internal row size calculation error");
/* Don't expect this to ever happen: */
if (row_width == 0)
png_error(png_ptr, "internal row width error");
/* Preserve the last byte in cases where only part of it will be overwritten,
* the multiply below may overflow, we don't care because ANSI-C guarantees
* we get the low bits.
*/
end_mask = (pixel_depth * row_width) & 7;
if (end_mask != 0)
{
/* end_ptr == NULL is a flag to say do nothing */
end_ptr = dp + PNG_ROWBYTES(pixel_depth, row_width) - 1;
end_byte = *end_ptr;
# ifdef PNG_READ_PACKSWAP_SUPPORTED
if (png_ptr->transformations & PNG_PACKSWAP) /* little-endian byte */
end_mask = 0xff << end_mask;
else /* big-endian byte */
# endif
end_mask = 0xff >> end_mask;
/* end_mask is now the bits to *keep* from the destination row */
}
/* For non-interlaced images this reduces to a png_memcpy(). A png_memcpy()
* will also happen if interlacing isn't supported or if the application
* does not call png_set_interlace_handling(). In the latter cases the
* caller just gets a sequence of the unexpanded rows from each interlace
* pass.
*/
#ifdef PNG_READ_INTERLACING_SUPPORTED
if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE) &&
pass < 6 && (display == 0 ||
/* The following copies everything for 'display' on passes 0, 2 and 4. */
(display == 1 && (pass & 1) != 0)))
{
/* Narrow images may have no bits in a pass; the caller should handle
* this, but this test is cheap:
*/
if (row_width <= PNG_PASS_START_COL(pass))
return;
if (pixel_depth < 8)
{
/* For pixel depths up to 4-bpp the 8-pixel mask can be expanded to fit
* into 32 bits, then a single loop over the bytes using the four byte
* values in the 32-bit mask can be used. For the 'display' option the
* expanded mask may also not require any masking within a byte. To
* make this work the PACKSWAP option must be taken into account - it
* simply requires the pixels to be reversed in each byte.
*
* The 'regular' case requires a mask for each of the first 6 passes,
* the 'display' case does a copy for the even passes in the range
* 0..6. This has already been handled in the tst above.
*
* The masks are arranged as four bytes with the first byte to use in
* the lowest bits (little-endian) regardless of the order (PACKSWAP or
* not) of the pixels in each byte.
*
* NOTE: the whole of this logic depends on the caller of this function
* only calling it on rows appropriate to the pass. This function only
* understands the 'x' logic, the 'y' logic is handled by the caller.
*
* The following defines allow generation of compile time constant bit
* masks for each pixel depth and each possibility of swapped or not
* swapped bytes. Pass 'p' is in the range 0..6; 'x', a pixel index,
* is in the range 0..7; and the result is 1 if the pixel is to be
* copied in the pass, 0 if not. 'S' is for the sparkle method, 'B'
* for the block method.
*
* With some compilers a compile time expression of the general form:
*
* (shift >= 32) ? (a >> (shift-32)) : (b >> shift)
*
* Produces warnings with values of 'shift' in the range 33 to 63
* because the right hand side of the ?: expression is evaluated by
* the compiler even though it isn't used. Microsoft Visual C (various
* versions) and the Intel C compiler are known to do this. To avoid
* this the following macros are used in 1.5.6. This is a temporary
* solution to avoid destablizing the code during the release process.
*/
# if PNG_USE_COMPILE_TIME_MASKS
# define PNG_LSR(x,s) ((x)>>((s) & 0x1f))
# define PNG_LSL(x,s) ((x)<<((s) & 0x1f))
# else
# define PNG_LSR(x,s) ((x)>>(s))
# define PNG_LSL(x,s) ((x)<<(s))
# endif
# define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\
PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1)
# define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\
PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1)
/* Return a mask for pass 'p' pixel 'x' at depth 'd'. The mask is
* little endian - the first pixel is at bit 0 - however the extra
* parameter 's' can be set to cause the mask position to be swapped
* within each byte, to match the PNG format. This is done by XOR of
* the shift with 7, 6 or 4 for bit depths 1, 2 and 4.
*/
# define PIXEL_MASK(p,x,d,s) \
(PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0))))
/* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask.
*/
# define S_MASKx(p,x,d,s) (S_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
# define B_MASKx(p,x,d,s) (B_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
/* Combine 8 of these to get the full mask. For the 1-bpp and 2-bpp
* cases the result needs replicating, for the 4-bpp case the above
* generates a full 32 bits.
*/
# define MASK_EXPAND(m,d) ((m)*((d)==1?0x01010101:((d)==2?0x00010001:1)))
# define S_MASK(p,d,s) MASK_EXPAND(S_MASKx(p,0,d,s) + S_MASKx(p,1,d,s) +\
S_MASKx(p,2,d,s) + S_MASKx(p,3,d,s) + S_MASKx(p,4,d,s) +\
S_MASKx(p,5,d,s) + S_MASKx(p,6,d,s) + S_MASKx(p,7,d,s), d)
# define B_MASK(p,d,s) MASK_EXPAND(B_MASKx(p,0,d,s) + B_MASKx(p,1,d,s) +\
B_MASKx(p,2,d,s) + B_MASKx(p,3,d,s) + B_MASKx(p,4,d,s) +\
B_MASKx(p,5,d,s) + B_MASKx(p,6,d,s) + B_MASKx(p,7,d,s), d)
#if PNG_USE_COMPILE_TIME_MASKS
/* Utility macros to construct all the masks for a depth/swap
* combination. The 's' parameter says whether the format is PNG
* (big endian bytes) or not. Only the three odd numbered passes are
* required for the display/block algorithm.
*/
# define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\
S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) }
# define B_MASKS(d,s) { B_MASK(1,d,s), S_MASK(3,d,s), S_MASK(5,d,s) }
# define DEPTH_INDEX(d) ((d)==1?0:((d)==2?1:2))
/* Hence the pre-compiled masks indexed by PACKSWAP (or not), depth and
* then pass:
*/
static PNG_CONST png_uint_32 row_mask[2/*PACKSWAP*/][3/*depth*/][6] = {
/* Little-endian byte masks for PACKSWAP */
{ S_MASKS(1,0), S_MASKS(2,0), S_MASKS(4,0) },
/* Normal (big-endian byte) masks - PNG format */
{ S_MASKS(1,1), S_MASKS(2,1), S_MASKS(4,1) }
};
/* display_mask has only three entries for the odd passes, so index by
* pass>>1.
*/
static PNG_CONST png_uint_32 display_mask[2][3][3] = {
/* Little-endian byte masks for PACKSWAP */
{ B_MASKS(1,0), B_MASKS(2,0), B_MASKS(4,0) },
/* Normal (big-endian byte) masks - PNG format */
{ B_MASKS(1,1), B_MASKS(2,1), B_MASKS(4,1) }
};
# define MASK(pass,depth,display,png)\
((display)?display_mask[png][DEPTH_INDEX(depth)][pass>>1]:\
row_mask[png][DEPTH_INDEX(depth)][pass])
#else /* !PNG_USE_COMPILE_TIME_MASKS */
/* This is the runtime alternative: it seems unlikely that this will
* ever be either smaller or faster than the compile time approach.
*/
# define MASK(pass,depth,display,png)\
((display)?B_MASK(pass,depth,png):S_MASK(pass,depth,png))
#endif /* !PNG_USE_COMPILE_TIME_MASKS */
/* Use the appropriate mask to copy the required bits. In some cases
* the byte mask will be 0 or 0xff, optimize these cases. row_width is
* the number of pixels, but the code copies bytes, so it is necessary
* to special case the end.
*/
png_uint_32 pixels_per_byte = 8 / pixel_depth;
png_uint_32 mask;
# ifdef PNG_READ_PACKSWAP_SUPPORTED
if (png_ptr->transformations & PNG_PACKSWAP)
mask = MASK(pass, pixel_depth, display, 0);
else
# endif
mask = MASK(pass, pixel_depth, display, 1);
for (;;)
{
png_uint_32 m;
/* It doesn't matter in the following if png_uint_32 has more than
* 32 bits because the high bits always match those in m<<24; it is,
* however, essential to use OR here, not +, because of this.
*/
m = mask;
mask = (m >> 8) | (m << 24); /* rotate right to good compilers */
m &= 0xff;
if (m != 0) /* something to copy */
{
if (m != 0xff)
*dp = (png_byte)((*dp & ~m) | (*sp & m));
else
*dp = *sp;
}
/* NOTE: this may overwrite the last byte with garbage if the image
* is not an exact number of bytes wide; libpng has always done
* this.
*/
if (row_width <= pixels_per_byte)
break; /* May need to restore part of the last byte */
row_width -= pixels_per_byte;
++dp;
++sp;
}
}
else /* pixel_depth >= 8 */
{
unsigned int bytes_to_copy, bytes_to_jump;
/* Validate the depth - it must be a multiple of 8 */
if (pixel_depth & 7)
png_error(png_ptr, "invalid user transform pixel depth");
pixel_depth >>= 3; /* now in bytes */
row_width *= pixel_depth;
/* Regardless of pass number the Adam 7 interlace always results in a
* fixed number of pixels to copy then to skip. There may be a
* different number of pixels to skip at the start though.
*/
{
unsigned int offset = PNG_PASS_START_COL(pass) * pixel_depth;
row_width -= offset;
dp += offset;
sp += offset;
}
/* Work out the bytes to copy. */
if (display)
{
/* When doing the 'block' algorithm the pixel in the pass gets
* replicated to adjacent pixels. This is why the even (0,2,4,6)
* passes are skipped above - the entire expanded row is copied.
*/
bytes_to_copy = (1<<((6-pass)>>1)) * pixel_depth;
/* But don't allow this number to exceed the actual row width. */
if (bytes_to_copy > row_width)
bytes_to_copy = row_width;
}
else /* normal row; Adam7 only ever gives us one pixel to copy. */
bytes_to_copy = pixel_depth;
/* In Adam7 there is a constant offset between where the pixels go. */
bytes_to_jump = PNG_PASS_COL_OFFSET(pass) * pixel_depth;
/* And simply copy these bytes. Some optimization is possible here,
* depending on the value of 'bytes_to_copy'. Special case the low
* byte counts, which we know to be frequent.
*
* Notice that these cases all 'return' rather than 'break' - this
* avoids an unnecessary test on whether to restore the last byte
* below.
*/
switch (bytes_to_copy)
{
case 1:
for (;;)
{
*dp = *sp;
if (row_width <= bytes_to_jump)
return;
dp += bytes_to_jump;
sp += bytes_to_jump;
row_width -= bytes_to_jump;
}
case 2:
/* There is a possibility of a partial copy at the end here; this
* slows the code down somewhat.
*/
do
{
dp[0] = sp[0], dp[1] = sp[1];
if (row_width <= bytes_to_jump)
return;
sp += bytes_to_jump;
dp += bytes_to_jump;
row_width -= bytes_to_jump;
}
while (row_width > 1);
/* And there can only be one byte left at this point: */
*dp = *sp;
return;
case 3:
/* This can only be the RGB case, so each copy is exactly one
* pixel and it is not necessary to check for a partial copy.
*/
for(;;)
{
dp[0] = sp[0], dp[1] = sp[1], dp[2] = sp[2];
if (row_width <= bytes_to_jump)
return;
sp += bytes_to_jump;
dp += bytes_to_jump;
row_width -= bytes_to_jump;
}
default:
#if PNG_ALIGN_TYPE != PNG_ALIGN_NONE
/* Check for double byte alignment and, if possible, use a
* 16-bit copy. Don't attempt this for narrow images - ones that
* are less than an interlace panel wide. Don't attempt it for
* wide bytes-to-copy either - use the png_memcpy there.
*/
if (bytes_to_copy < 16 /*else use png_memcpy*/ &&
png_isaligned(dp, png_uint_16) &&
png_isaligned(sp, png_uint_16) &&
bytes_to_copy % sizeof (png_uint_16) == 0 &&
bytes_to_jump % sizeof (png_uint_16) == 0)
{
/* Everything is aligned for png_uint_16 copies, but try for
* png_uint_32 first.
*/
if (png_isaligned(dp, png_uint_32) &&
png_isaligned(sp, png_uint_32) &&
bytes_to_copy % sizeof (png_uint_32) == 0 &&
bytes_to_jump % sizeof (png_uint_32) == 0)
{
png_uint_32p dp32 = (png_uint_32p)dp;
png_const_uint_32p sp32 = (png_const_uint_32p)sp;
unsigned int skip = (bytes_to_jump-bytes_to_copy) /
sizeof (png_uint_32);
do
{
size_t c = bytes_to_copy;
do
{
*dp32++ = *sp32++;
c -= sizeof (png_uint_32);
}
while (c > 0);
if (row_width <= bytes_to_jump)
return;
dp32 += skip;
sp32 += skip;
row_width -= bytes_to_jump;
}
while (bytes_to_copy <= row_width);
/* Get to here when the row_width truncates the final copy.
* There will be 1-3 bytes left to copy, so don't try the
* 16-bit loop below.
*/
dp = (png_bytep)dp32;
sp = (png_const_bytep)sp32;
do
*dp++ = *sp++;
while (--row_width > 0);
return;
}
/* Else do it in 16-bit quantities, but only if the size is
* not too large.
*/
else
{
png_uint_16p dp16 = (png_uint_16p)dp;
png_const_uint_16p sp16 = (png_const_uint_16p)sp;
unsigned int skip = (bytes_to_jump-bytes_to_copy) /
sizeof (png_uint_16);
do
{
size_t c = bytes_to_copy;
do
{
*dp16++ = *sp16++;
c -= sizeof (png_uint_16);
}
while (c > 0);
if (row_width <= bytes_to_jump)
return;
dp16 += skip;
sp16 += skip;
row_width -= bytes_to_jump;
}
while (bytes_to_copy <= row_width);
/* End of row - 1 byte left, bytes_to_copy > row_width: */
dp = (png_bytep)dp16;
sp = (png_const_bytep)sp16;
do
*dp++ = *sp++;
while (--row_width > 0);
return;
}
}
#endif /* PNG_ALIGN_ code */
/* The true default - use a png_memcpy: */
for (;;)
{
png_memcpy(dp, sp, bytes_to_copy);
if (row_width <= bytes_to_jump)
return;
sp += bytes_to_jump;
dp += bytes_to_jump;
row_width -= bytes_to_jump;
if (bytes_to_copy > row_width)
bytes_to_copy = row_width;
}
}
/* NOT REACHED*/
} /* pixel_depth >= 8 */
/* Here if pixel_depth < 8 to check 'end_ptr' below. */
}
else
#endif
/* If here then the switch above wasn't used so just png_memcpy the whole row
* from the temporary row buffer (notice that this overwrites the end of the
* destination row if it is a partial byte.)
*/
png_memcpy(dp, sp, PNG_ROWBYTES(pixel_depth, row_width));
/* Restore the overwritten bits from the last byte if necessary. */
if (end_ptr != NULL)
*end_ptr = (png_byte)((end_byte & end_mask) | (*end_ptr & ~end_mask));
}
#ifdef PNG_READ_INTERLACING_SUPPORTED
void /* PRIVATE */
png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
png_uint_32 transformations /* Because these may affect the byte layout */)
{
/* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
/* Offset to next interlace block */
static PNG_CONST int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
png_debug(1, "in png_do_read_interlace");
if (row != NULL && row_info != NULL)
{
png_uint_32 final_width;
final_width = row_info->width * png_pass_inc[pass];
switch (row_info->pixel_depth)
{
case 1:
{
png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 3);
png_bytep dp = row + (png_size_t)((final_width - 1) >> 3);
int sshift, dshift;
int s_start, s_end, s_inc;
int jstop = png_pass_inc[pass];
png_byte v;
png_uint_32 i;
int j;
#ifdef PNG_READ_PACKSWAP_SUPPORTED
if (transformations & PNG_PACKSWAP)
{
sshift = (int)((row_info->width + 7) & 0x07);
dshift = (int)((final_width + 7) & 0x07);
s_start = 7;
s_end = 0;
s_inc = -1;
}
else
#endif
{
sshift = 7 - (int)((row_info->width + 7) & 0x07);
dshift = 7 - (int)((final_width + 7) & 0x07);
s_start = 0;
s_end = 7;
s_inc = 1;
}
for (i = 0; i < row_info->width; i++)
{
v = (png_byte)((*sp >> sshift) & 0x01);
for (j = 0; j < jstop; j++)
{
*dp &= (png_byte)((0x7f7f >> (7 - dshift)) & 0xff);
*dp |= (png_byte)(v << dshift);
if (dshift == s_end)
{
dshift = s_start;
dp--;
}
else
dshift += s_inc;
}
if (sshift == s_end)
{
sshift = s_start;
sp--;
}
else
sshift += s_inc;
}
break;
}
case 2:
{
png_bytep sp = row + (png_uint_32)((row_info->width - 1) >> 2);
png_bytep dp = row + (png_uint_32)((final_width - 1) >> 2);
int sshift, dshift;
int s_start, s_end, s_inc;
int jstop = png_pass_inc[pass];
png_uint_32 i;
#ifdef PNG_READ_PACKSWAP_SUPPORTED
if (transformations & PNG_PACKSWAP)
{
sshift = (int)(((row_info->width + 3) & 0x03) << 1);
dshift = (int)(((final_width + 3) & 0x03) << 1);
s_start = 6;
s_end = 0;
s_inc = -2;
}
else
#endif
{
sshift = (int)((3 - ((row_info->width + 3) & 0x03)) << 1);
dshift = (int)((3 - ((final_width + 3) & 0x03)) << 1);
s_start = 0;
s_end = 6;
s_inc = 2;
}
for (i = 0; i < row_info->width; i++)
{
png_byte v;
int j;
v = (png_byte)((*sp >> sshift) & 0x03);
for (j = 0; j < jstop; j++)
{
*dp &= (png_byte)((0x3f3f >> (6 - dshift)) & 0xff);
*dp |= (png_byte)(v << dshift);
if (dshift == s_end)
{
dshift = s_start;
dp--;
}
else
dshift += s_inc;
}
if (sshift == s_end)
{
sshift = s_start;
sp--;
}
else
sshift += s_inc;
}
break;
}
case 4:
{
png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 1);
png_bytep dp = row + (png_size_t)((final_width - 1) >> 1);
int sshift, dshift;
int s_start, s_end, s_inc;
png_uint_32 i;
int jstop = png_pass_inc[pass];
#ifdef PNG_READ_PACKSWAP_SUPPORTED
if (transformations & PNG_PACKSWAP)
{
sshift = (int)(((row_info->width + 1) & 0x01) << 2);
dshift = (int)(((final_width + 1) & 0x01) << 2);
s_start = 4;
s_end = 0;
s_inc = -4;
}
else
#endif
{
sshift = (int)((1 - ((row_info->width + 1) & 0x01)) << 2);
dshift = (int)((1 - ((final_width + 1) & 0x01)) << 2);
s_start = 0;
s_end = 4;
s_inc = 4;
}
for (i = 0; i < row_info->width; i++)
{
png_byte v = (png_byte)((*sp >> sshift) & 0x0f);
int j;
for (j = 0; j < jstop; j++)
{
*dp &= (png_byte)((0xf0f >> (4 - dshift)) & 0xff);
*dp |= (png_byte)(v << dshift);
if (dshift == s_end)
{
dshift = s_start;
dp--;
}
else
dshift += s_inc;
}
if (sshift == s_end)
{
sshift = s_start;
sp--;
}
else
sshift += s_inc;
}
break;
}
default:
{
png_size_t pixel_bytes = (row_info->pixel_depth >> 3);
png_bytep sp = row + (png_size_t)(row_info->width - 1)
* pixel_bytes;
png_bytep dp = row + (png_size_t)(final_width - 1) * pixel_bytes;
int jstop = png_pass_inc[pass];
png_uint_32 i;
for (i = 0; i < row_info->width; i++)
{
png_byte v[8];
int j;
png_memcpy(v, sp, pixel_bytes);
for (j = 0; j < jstop; j++)
{
png_memcpy(dp, v, pixel_bytes);
dp -= pixel_bytes;
}
sp -= pixel_bytes;
}
break;
}
}
row_info->width = final_width;
row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, final_width);
}
#ifndef PNG_READ_PACKSWAP_SUPPORTED
PNG_UNUSED(transformations) /* Silence compiler warning */
#endif
}
#endif /* PNG_READ_INTERLACING_SUPPORTED */
static void
png_read_filter_row_sub(png_row_infop row_info, png_bytep row,
png_const_bytep prev_row)
{
png_size_t i;
png_size_t istop = row_info->rowbytes;
unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
png_bytep rp = row + bpp;
png_bytep lp = row;
PNG_UNUSED(prev_row)
for (i = bpp; i < istop; i++)
{
*rp = (png_byte)(((int)(*rp) + (int)(*lp++)) & 0xff);
rp++;
}
}
static void
png_read_filter_row_up(png_row_infop row_info, png_bytep row,
png_const_bytep prev_row)
{
png_size_t i;
png_size_t istop = row_info->rowbytes;
png_bytep rp = row;
png_const_bytep pp = prev_row;
for (i = 0; i < istop; i++)
{
*rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
rp++;
}
}
static void
png_read_filter_row_avg(png_row_infop row_info, png_bytep row,
png_const_bytep prev_row)
{
png_size_t i;
png_bytep rp = row;
png_const_bytep pp = prev_row;
png_bytep lp = row;
unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
png_size_t istop = row_info->rowbytes - bpp;
for (i = 0; i < bpp; i++)
{
*rp = (png_byte)(((int)(*rp) +
((int)(*pp++) / 2 )) & 0xff);
rp++;
}
for (i = 0; i < istop; i++)
{
*rp = (png_byte)(((int)(*rp) +
(int)(*pp++ + *lp++) / 2 ) & 0xff);
rp++;
}
}
static void
png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info, png_bytep row,
png_const_bytep prev_row)
{
png_bytep rp_end = row + row_info->rowbytes;
int a, c;
/* First pixel/byte */
c = *prev_row++;
a = *row + c;
*row++ = (png_byte)a;
/* Remainder */
while (row < rp_end)
{
int b, pa, pb, pc, p;
a &= 0xff; /* From previous iteration or start */
b = *prev_row++;
p = b - c;
pc = a - c;
# ifdef PNG_USE_ABS
pa = abs(p);
pb = abs(pc);
pc = abs(p + pc);
# else
pa = p < 0 ? -p : p;
pb = pc < 0 ? -pc : pc;
pc = (p + pc) < 0 ? -(p + pc) : p + pc;
# endif
/* Find the best predictor, the least of pa, pb, pc favoring the earlier
* ones in the case of a tie.
*/
if (pb < pa) pa = pb, a = b;
if (pc < pa) a = c;
/* Calculate the current pixel in a, and move the previous row pixel to c
* for the next time round the loop
*/
c = b;
a += *row;
*row++ = (png_byte)a;
}
}
static void
png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row,
png_const_bytep prev_row)
{
int bpp = (row_info->pixel_depth + 7) >> 3;
png_bytep rp_end = row + bpp;
/* Process the first pixel in the row completely (this is the same as 'up'
* because there is only one candidate predictor for the first row).
*/
while (row < rp_end)
{
int a = *row + *prev_row++;
*row++ = (png_byte)a;
}
/* Remainder */
rp_end += row_info->rowbytes - bpp;
while (row < rp_end)
{
int a, b, c, pa, pb, pc, p;
c = *(prev_row - bpp);
a = *(row - bpp);
b = *prev_row++;
p = b - c;
pc = a - c;
# ifdef PNG_USE_ABS
pa = abs(p);
pb = abs(pc);
pc = abs(p + pc);
# else
pa = p < 0 ? -p : p;
pb = pc < 0 ? -pc : pc;
pc = (p + pc) < 0 ? -(p + pc) : p + pc;
# endif
if (pb < pa) pa = pb, a = b;
if (pc < pa) a = c;
c = b;
a += *row;
*row++ = (png_byte)a;
}
}
#ifdef PNG_ARM_NEON
static void
png_init_filter_functions_neon(png_structp pp, unsigned int bpp)
{
pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_neon;
if (bpp == 3) {
pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_neon;
pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_neon;
pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth3_neon;
} else if (bpp == 4) {
pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_neon;
pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_neon;
pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth4_neon;
}
}
#endif
static void
png_init_filter_functions(png_structp pp)
{
unsigned int bpp = (pp->pixel_depth + 7) >> 3;
pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub;
pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up;
pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg;
if (bpp == 1)
pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
png_read_filter_row_paeth_1byte_pixel;
else
pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
png_read_filter_row_paeth_multibyte_pixel;
#ifdef PNG_ARM_NEON
png_init_filter_functions_neon(pp, bpp);
#endif
}
void /* PRIVATE */
png_read_filter_row(png_structp pp, png_row_infop row_info, png_bytep row,
png_const_bytep prev_row, int filter)
{
if (pp->read_filter[0] == NULL)
png_init_filter_functions(pp);
if (filter > PNG_FILTER_VALUE_NONE && filter < PNG_FILTER_VALUE_LAST)
pp->read_filter[filter-1](row_info, row, prev_row);
}
#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
void /* PRIVATE */
png_read_finish_row(png_structp png_ptr)
{
#ifdef PNG_READ_INTERLACING_SUPPORTED
/* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
/* Start of interlace block */
static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
/* Offset to next interlace block */
static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
/* Start of interlace block in the y direction */
static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
/* Offset to next interlace block in the y direction */
static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
#endif /* PNG_READ_INTERLACING_SUPPORTED */
png_debug(1, "in png_read_finish_row");
png_ptr->row_number++;
if (png_ptr->row_number < png_ptr->num_rows)
return;
#ifdef PNG_READ_INTERLACING_SUPPORTED
if (png_ptr->interlaced)
{
png_ptr->row_number = 0;
/* TO DO: don't do this if prev_row isn't needed (requires
* read-ahead of the next row's filter byte.
*/
png_memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
do
{
png_ptr->pass++;
if (png_ptr->pass >= 7)
break;
png_ptr->iwidth = (png_ptr->width +
png_pass_inc[png_ptr->pass] - 1 -
png_pass_start[png_ptr->pass]) /
png_pass_inc[png_ptr->pass];
if (!(png_ptr->transformations & PNG_INTERLACE))
{
png_ptr->num_rows = (png_ptr->height +
png_pass_yinc[png_ptr->pass] - 1 -
png_pass_ystart[png_ptr->pass]) /
png_pass_yinc[png_ptr->pass];
}
else /* if (png_ptr->transformations & PNG_INTERLACE) */
break; /* libpng deinterlacing sees every row */
} while (png_ptr->num_rows == 0 || png_ptr->iwidth == 0);
if (png_ptr->pass < 7)
return;
}
#endif /* PNG_READ_INTERLACING_SUPPORTED */
if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
{
char extra;
int ret;
png_ptr->zstream.next_out = (Byte *)&extra;
png_ptr->zstream.avail_out = (uInt)1;
for (;;)
{
if (!(png_ptr->zstream.avail_in))
{
while (!png_ptr->idat_size)
{
png_crc_finish(png_ptr, 0);
png_ptr->idat_size = png_read_chunk_header(png_ptr);
if (png_ptr->chunk_name != png_IDAT)
png_error(png_ptr, "Not enough image data");
}
png_ptr->zstream.avail_in = (uInt)png_ptr->zbuf_size;
png_ptr->zstream.next_in = png_ptr->zbuf;
if (png_ptr->zbuf_size > png_ptr->idat_size)
png_ptr->zstream.avail_in = (uInt)png_ptr->idat_size;
png_crc_read(png_ptr, png_ptr->zbuf, png_ptr->zstream.avail_in);
png_ptr->idat_size -= png_ptr->zstream.avail_in;
}
ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
if (ret == Z_STREAM_END)
{
if (!(png_ptr->zstream.avail_out) || png_ptr->zstream.avail_in ||
png_ptr->idat_size)
png_warning(png_ptr, "Extra compressed data");
png_ptr->mode |= PNG_AFTER_IDAT;
png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
break;
}
if (ret != Z_OK)
png_error(png_ptr, png_ptr->zstream.msg ? png_ptr->zstream.msg :
"Decompression Error");
if (!(png_ptr->zstream.avail_out))
{
png_warning(png_ptr, "Extra compressed data");
png_ptr->mode |= PNG_AFTER_IDAT;
png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
break;
}
}
png_ptr->zstream.avail_out = 0;
}
if (png_ptr->idat_size || png_ptr->zstream.avail_in)
png_warning(png_ptr, "Extra compression data");
inflateReset(&png_ptr->zstream);
png_ptr->mode |= PNG_AFTER_IDAT;
}
#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
void /* PRIVATE */
png_read_start_row(png_structp png_ptr)
{
#ifdef PNG_READ_INTERLACING_SUPPORTED
/* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
/* Start of interlace block */
static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
/* Offset to next interlace block */
static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
/* Start of interlace block in the y direction */
static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
/* Offset to next interlace block in the y direction */
static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
#endif
int max_pixel_depth;
png_size_t row_bytes;
png_debug(1, "in png_read_start_row");
png_ptr->zstream.avail_in = 0;
#ifdef PNG_READ_TRANSFORMS_SUPPORTED
png_init_read_transformations(png_ptr);
#endif
#ifdef PNG_READ_INTERLACING_SUPPORTED
if (png_ptr->interlaced)
{
if (!(png_ptr->transformations & PNG_INTERLACE))
png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
png_pass_ystart[0]) / png_pass_yinc[0];
else
png_ptr->num_rows = png_ptr->height;
png_ptr->iwidth = (png_ptr->width +
png_pass_inc[png_ptr->pass] - 1 -
png_pass_start[png_ptr->pass]) /
png_pass_inc[png_ptr->pass];
}
else
#endif /* PNG_READ_INTERLACING_SUPPORTED */
{
png_ptr->num_rows = png_ptr->height;
png_ptr->iwidth = png_ptr->width;
}
max_pixel_depth = png_ptr->pixel_depth;
#ifdef PNG_READ_PACK_SUPPORTED
if ((png_ptr->transformations & PNG_PACK) && png_ptr->bit_depth < 8)
max_pixel_depth = 8;
#endif
#ifdef PNG_READ_EXPAND_SUPPORTED
if (png_ptr->transformations & PNG_EXPAND)
{
if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
{
if (png_ptr->num_trans)
max_pixel_depth = 32;
else
max_pixel_depth = 24;
}
else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
{
if (max_pixel_depth < 8)
max_pixel_depth = 8;
if (png_ptr->num_trans)
max_pixel_depth *= 2;
}
else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
{
if (png_ptr->num_trans)
{
max_pixel_depth *= 4;
max_pixel_depth /= 3;
}
}
}
#endif
#ifdef PNG_READ_EXPAND_16_SUPPORTED
if (png_ptr->transformations & PNG_EXPAND_16)
{
# ifdef PNG_READ_EXPAND_SUPPORTED
/* In fact it is an error if it isn't supported, but checking is
* the safe way.
*/
if (png_ptr->transformations & PNG_EXPAND)
{
if (png_ptr->bit_depth < 16)
max_pixel_depth *= 2;
}
else
# endif
png_ptr->transformations &= ~PNG_EXPAND_16;
}
#endif
#ifdef PNG_READ_FILLER_SUPPORTED
if (png_ptr->transformations & (PNG_FILLER))
{
if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
max_pixel_depth = 32;
else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
{
if (max_pixel_depth <= 8)
max_pixel_depth = 16;
else
max_pixel_depth = 32;
}
else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
{
if (max_pixel_depth <= 32)
max_pixel_depth = 32;
else
max_pixel_depth = 64;
}
}
#endif
#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
if (png_ptr->transformations & PNG_GRAY_TO_RGB)
{
if (
#ifdef PNG_READ_EXPAND_SUPPORTED
(png_ptr->num_trans && (png_ptr->transformations & PNG_EXPAND)) ||
#endif
#ifdef PNG_READ_FILLER_SUPPORTED
(png_ptr->transformations & (PNG_FILLER)) ||
#endif
png_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
{
if (max_pixel_depth <= 16)
max_pixel_depth = 32;
else
max_pixel_depth = 64;
}
else
{
if (max_pixel_depth <= 8)
{
if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
max_pixel_depth = 32;
else
max_pixel_depth = 24;
}
else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
max_pixel_depth = 64;
else
max_pixel_depth = 48;
}
}
#endif
#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) && \
defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
if (png_ptr->transformations & PNG_USER_TRANSFORM)
{
int user_pixel_depth = png_ptr->user_transform_depth *
png_ptr->user_transform_channels;
if (user_pixel_depth > max_pixel_depth)
max_pixel_depth = user_pixel_depth;
}
#endif
/* This value is stored in png_struct and double checked in the row read
* code.
*/
png_ptr->maximum_pixel_depth = (png_byte)max_pixel_depth;
png_ptr->transformed_pixel_depth = 0; /* calculated on demand */
/* Align the width on the next larger 8 pixels. Mainly used
* for interlacing
*/
row_bytes = ((png_ptr->width + 7) & ~((png_uint_32)7));
/* Calculate the maximum bytes needed, adding a byte and a pixel
* for safety's sake
*/
row_bytes = PNG_ROWBYTES(max_pixel_depth, row_bytes) +
1 + ((max_pixel_depth + 7) >> 3);
#ifdef PNG_MAX_MALLOC_64K
if (row_bytes > (png_uint_32)65536L)
png_error(png_ptr, "This image requires a row greater than 64KB");
#endif
if (row_bytes + 48 > png_ptr->old_big_row_buf_size)
{
png_free(png_ptr, png_ptr->big_row_buf);
png_free(png_ptr, png_ptr->big_prev_row);
if (png_ptr->interlaced)
png_ptr->big_row_buf = (png_bytep)png_calloc(png_ptr,
row_bytes + 48);
else
png_ptr->big_row_buf = (png_bytep)png_malloc(png_ptr, row_bytes + 48);
png_ptr->big_prev_row = (png_bytep)png_malloc(png_ptr, row_bytes + 48);
#ifdef PNG_ALIGNED_MEMORY_SUPPORTED
/* Use 16-byte aligned memory for row_buf with at least 16 bytes
* of padding before and after row_buf; treat prev_row similarly.
* NOTE: the alignment is to the start of the pixels, one beyond the start
* of the buffer, because of the filter byte. Prior to libpng 1.5.6 this
* was incorrect; the filter byte was aligned, which had the exact
* opposite effect of that intended.
*/
{
png_bytep temp = png_ptr->big_row_buf + 32;
int extra = (int)((temp - (png_bytep)0) & 0x0f);
png_ptr->row_buf = temp - extra - 1/*filter byte*/;
temp = png_ptr->big_prev_row + 32;
extra = (int)((temp - (png_bytep)0) & 0x0f);
png_ptr->prev_row = temp - extra - 1/*filter byte*/;
}
#else
/* Use 31 bytes of padding before and 17 bytes after row_buf. */
png_ptr->row_buf = png_ptr->big_row_buf + 31;
png_ptr->prev_row = png_ptr->big_prev_row + 31;
#endif
png_ptr->old_big_row_buf_size = row_bytes + 48;
}
#ifdef PNG_MAX_MALLOC_64K
if (png_ptr->rowbytes > 65535)
png_error(png_ptr, "This image requires a row greater than 64KB");
#endif
if (png_ptr->rowbytes > (PNG_SIZE_MAX - 1))
png_error(png_ptr, "Row has too many bytes to allocate in memory");
png_memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
png_debug1(3, "width = %u,", png_ptr->width);
png_debug1(3, "height = %u,", png_ptr->height);
png_debug1(3, "iwidth = %u,", png_ptr->iwidth);
png_debug1(3, "num_rows = %u,", png_ptr->num_rows);
png_debug1(3, "rowbytes = %lu,", (unsigned long)png_ptr->rowbytes);
png_debug1(3, "irowbytes = %lu",
(unsigned long)PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->iwidth) + 1);
png_ptr->flags |= PNG_FLAG_ROW_INIT;
}
#endif /* PNG_READ_SUPPORTED */
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