Google Git
Sign in
skia / third_party / libpng / 77cc76ed61a3531630d7c319d81157b978a33759 / . / pngrutil.c
blob: dbcfd05ac7078742d1905b1371acd1cce95ae2b6 [file] [log] [blame]
/* pngrutil.c - utilities to read a PNG file
*
* Last changed in libpng 1.5.30 [(PENDING RELEASE)]
* Copyright (c) 1998-2002,2004,2006-2015,2017 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
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 */
if ((uval & 0x80000000) == 0) /* no overflow */
return -(png_int_32)uval;
/* The following has to be safe; this function only gets called on PNG data
* and if we get here that data is invalid. 0 is the most safe value and
* if not then an attacker would surely just generate a PNG with 0 instead.
*/
return 0;
}
/* 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);
/* Check to see if chunk name is valid. */
png_check_chunk_name(png_ptr, png_ptr->chunk_name);
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 for too-large chunk length */
png_check_chunk_length(png_ptr, length);
#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 != 0)
{
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 != 0)
{
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;
/* HACK: added in libpng 1.5.18: the progressive reader always leaves
* png_ptr->zstream in a non-reset state. This causes a reset if it needs to
* be used again. This only copes with that one specific error; see libpng
* 1.6 for a better solution.
*/
if ((png_ptr->flags & PNG_FLAG_ZSTREAM_PROGRESSIVE) != 0)
{
(void)inflateReset(&png_ptr->zstream);
png_ptr->flags &= ~PNG_FLAG_ZSTREAM_PROGRESSIVE;
}
/* 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.
*/
if (prefix_size >= (~(png_size_t)0) - 1 ||
expanded_size >= (~(png_size_t)0) - 1 - prefix_size
#ifdef PNG_USER_LIMITS_SUPPORTED
|| (png_ptr->user_chunk_malloc_max &&
(prefix_size + expanded_size >= png_ptr->user_chunk_malloc_max - 1))
#else
|| ((PNG_USER_CHUNK_MALLOC_MAX > 0) &&
prefix_size + expanded_size >= PNG_USER_CHUNK_MALLOC_MAX - 1)
#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.
*/
else if (expanded_size > 0)
{
/* 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);
memset(text, 0, prefix_size + expanded_size + 1); /* just in case */
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 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 max_palette_length, 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");
}
}
/* The cast is safe because 'length' is less than 3*PNG_MAX_PALETTE_LENGTH */
num = (int)length / 3;
/* If the palette has 256 or fewer entries but is too large for the bit
* depth, we don't issue an error, to preserve the behavior of previous
* libpng versions. We silently truncate the unused extra palette entries
* here.
*/
if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
max_palette_length = (1 << png_ptr->bit_depth);
else
max_palette_length = PNG_MAX_PALETTE_LENGTH;
if (num > max_palette_length)
num = max_palette_length;
#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, (int) length - num * 3);
}
#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 ((png_ptr->mode & PNG_HAVE_iCCP) || (info_ptr != NULL &&
(info_ptr->valid & (PNG_INFO_iCCP|PNG_INFO_sRGB))))
{
png_warning(png_ptr, "Duplicate iCCP chunk");
png_crc_finish(png_ptr, length);
return;
}
png_ptr->mode |= PNG_HAVE_iCCP;
#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 = 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 (slength < 1U || profile >= png_ptr->chunkdata + slength - 1U)
{
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 != 0)
{
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 = 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 (slength < 2U ||
entry_start > (png_bytep)png_ptr->chunkdata + slength - 2U)
{
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;
}
if (length > 2*PNG_MAX_PALETTE_LENGTH ||
length != (unsigned int) (2*png_ptr->num_palette))
{
png_warning(png_ptr, "Incorrect hIST chunk length");
png_crc_finish(png_ptr, length);
return;
}
num = length / 2 ;
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 = 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 = 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 = 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 != 0)
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 = 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 (slength < 2U || text >= png_ptr->chunkdata + slength - 2U)
{
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 != 0)
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;
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 = 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 (slength < 3U || lang >= png_ptr->chunkdata + slength - 3U)
{
png_warning(png_ptr, "Truncated iTXt chunk");
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
return;
}
comp_flag = *lang++;
comp_type = *lang++;
/* 1.5.14: The spec says "for uncompressed text decoders shall ignore [the
* compression type]". The compression flag shall be 0 (no compression) or
* 1 (compressed with method 0 - deflate.)
*/
if (comp_flag/*compressed*/ != 0)
{
if (comp_flag != 1)
{
png_warning(png_ptr, "invalid iTXt compression flag");
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
return;
}
if (comp_type != 0)
{
png_warning(png_ptr, "unknown iTXt compression type");
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
return;
}
}
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/*compressed*/)
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 =
(comp_flag ? PNG_ITXT_COMPRESSION_zTXt : PNG_ITXT_COMPRESSION_NONE);
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 != 0)
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_uint_32 cn=chunk_name;
png_debug(1, "in png_check_chunk_name");
for (i=1; i<=4; ++i)
{
int c = cn & 0xff;
if (c < 65 || c > 122 || (c > 90 && c < 97))
png_chunk_error(png_ptr, "invalid chunk type");
cn >>= 8;
}
}
void /* PRIVATE */
png_check_chunk_length(png_structp png_ptr, png_uint_32 length)
{
png_uint_32 limit = PNG_UINT_31_MAX;
# ifdef PNG_SET_USER_LIMITS_SUPPORTED
if (png_ptr->user_chunk_malloc_max > 0 &&
png_ptr->user_chunk_malloc_max < limit)
limit = png_ptr->user_chunk_malloc_max;
# elif PNG_USER_CHUNK_MALLOC_MAX > 0
if (PNG_USER_CHUNK_MALLOC_MAX < limit)
limit = PNG_USER_CHUNK_MALLOC_MAX;
# endif
if (png_ptr->chunk_name == png_IDAT)
{
png_alloc_size_t idat_limit = PNG_UINT_31_MAX;
size_t row_factor =
(png_ptr->width * png_ptr->channels * (png_ptr->bit_depth > 8? 2: 1)
+ 1 + (png_ptr->interlaced? 6: 0));
if (png_ptr->height > PNG_UINT_32_MAX/row_factor)
idat_limit=PNG_UINT_31_MAX;
else
idat_limit = png_ptr->height * row_factor;
row_factor = row_factor > 32566? 32566 : row_factor;
idat_limit += 6 + 5*(idat_limit/row_factor+1); /* zlib+deflate overhead */
idat_limit=idat_limit < PNG_UINT_31_MAX? idat_limit : PNG_UINT_31_MAX;
limit = limit < idat_limit? idat_limit : limit;
}
if (length > limit)
{
png_debug2(0," length = %lu, limit = %lu",
(unsigned long)length,(unsigned long)limit);
png_chunk_error(png_ptr, "chunk data is too large");
}
}
/* 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 'display' value; if 'display' is true then the whole row
* (dp) is filled from the start by replicating the available pixels. If
* 'display' is false only those pixels present in the pass are filled in.
*/
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_alloc_size_t 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 test 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 destabilizing 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), B_MASK(3,d,s), B_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 != 0)
{
/* 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 = (unsigned int)/*SAFE*/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;
size_t 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;
size_t 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 = (unsigned int)/*SAFE*/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]; /* SAFE; pixel_depth does not exceed 64 */
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_UNUSED(prev_row)
for (i = bpp; i < istop; i++)
{
*rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 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;
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++ + *(rp-bpp)) / 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;
}
}
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_FILTER_OPTIMIZATIONS
/* To use this define PNG_FILTER_OPTIMIZATIONS as the name of a function to
* call to install hardware optimizations for the above functions; simply
* replace whatever elements of the pp->read_filter[] array with a hardware
* specific (or, for that matter, generic) optimization.
*
* To see an example of this examine what configure.ac does when
* --enable-arm-neon is specified on the command line.
*/
PNG_FILTER_OPTIMIZATIONS(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 (filter > PNG_FILTER_VALUE_NONE && filter < PNG_FILTER_VALUE_LAST)
{
if (pp->read_filter[0] == NULL)
png_init_filter_functions(pp);
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;
/* WARNING: * png_read_transform_info (pngrtran.c) performs a simpliar set of
* calculations to calculate the final pixel depth, then
* png_do_read_transforms actually does the transforms. This means that the
* code which effectively calculates this value is actually repeated in three
* separate places. They must all match. Innocent changes to the order of
* transformations can and will break libpng in a way that causes memory
* overwrites.
*
* TODO: fix this.
*/
#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_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 ||
png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
{
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 */