/src/FreeImage/Source/LibPNG/pngrutil.c
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- /* pngrutil.c - utilities to read a PNG file
- *
- * Last changed in libpng 1.5.9 [February 18, 2012]
- * Copyright (c) 1998-2012 Glenn Randers-Pehrson
- * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
- * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- *
- * This file contains routines that are only called from within
- * libpng itself during the course of reading an image.
- */
- #include "pngpriv.h"
- #ifdef PNG_READ_SUPPORTED
- #define png_strtod(p,a,b) strtod(a,b)
- png_uint_32 PNGAPI
- png_get_uint_31(png_structp png_ptr, png_const_bytep buf)
- {
- png_uint_32 uval = png_get_uint_32(buf);
- if (uval > PNG_UINT_31_MAX)
- png_error(png_ptr, "PNG unsigned integer out of range");
- return (uval);
- }
- #if defined(PNG_READ_gAMA_SUPPORTED) || defined(PNG_READ_cHRM_SUPPORTED)
- /* The following is a variation on the above for use with the fixed
- * point values used for gAMA and cHRM. Instead of png_error it
- * issues a warning and returns (-1) - an invalid value because both
- * gAMA and cHRM use *unsigned* integers for fixed point values.
- */
- #define PNG_FIXED_ERROR (-1)
- static png_fixed_point /* PRIVATE */
- png_get_fixed_point(png_structp png_ptr, png_const_bytep buf)
- {
- png_uint_32 uval = png_get_uint_32(buf);
- if (uval <= PNG_UINT_31_MAX)
- return (png_fixed_point)uval; /* known to be in range */
- /* The caller can turn off the warning by passing NULL. */
- if (png_ptr != NULL)
- png_warning(png_ptr, "PNG fixed point integer out of range");
- return PNG_FIXED_ERROR;
- }
- #endif
- #ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
- /* NOTE: the read macros will obscure these definitions, so that if
- * PNG_USE_READ_MACROS is set the library will not use them internally,
- * but the APIs will still be available externally.
- *
- * The parentheses around "PNGAPI function_name" in the following three
- * functions are necessary because they allow the macros to co-exist with
- * these (unused but exported) functions.
- */
- /* Grab an unsigned 32-bit integer from a buffer in big-endian format. */
- png_uint_32 (PNGAPI
- png_get_uint_32)(png_const_bytep buf)
- {
- png_uint_32 uval =
- ((png_uint_32)(*(buf )) << 24) +
- ((png_uint_32)(*(buf + 1)) << 16) +
- ((png_uint_32)(*(buf + 2)) << 8) +
- ((png_uint_32)(*(buf + 3)) ) ;
- return uval;
- }
- /* Grab a signed 32-bit integer from a buffer in big-endian format. The
- * data is stored in the PNG file in two's complement format and there
- * is no guarantee that a 'png_int_32' is exactly 32 bits, therefore
- * the following code does a two's complement to native conversion.
- */
- png_int_32 (PNGAPI
- png_get_int_32)(png_const_bytep buf)
- {
- png_uint_32 uval = png_get_uint_32(buf);
- if ((uval & 0x80000000) == 0) /* non-negative */
- return uval;
- uval = (uval ^ 0xffffffff) + 1; /* 2's complement: -x = ~x+1 */
- return -(png_int_32)uval;
- }
- /* Grab an unsigned 16-bit integer from a buffer in big-endian format. */
- png_uint_16 (PNGAPI
- png_get_uint_16)(png_const_bytep buf)
- {
- /* ANSI-C requires an int value to accomodate at least 16 bits so this
- * works and allows the compiler not to worry about possible narrowing
- * on 32 bit systems. (Pre-ANSI systems did not make integers smaller
- * than 16 bits either.)
- */
- unsigned int val =
- ((unsigned int)(*buf) << 8) +
- ((unsigned int)(*(buf + 1)));
- return (png_uint_16)val;
- }
- #endif /* PNG_READ_INT_FUNCTIONS_SUPPORTED */
- /* Read and check the PNG file signature */
- void /* PRIVATE */
- png_read_sig(png_structp png_ptr, png_infop info_ptr)
- {
- png_size_t num_checked, num_to_check;
- /* Exit if the user application does not expect a signature. */
- if (png_ptr->sig_bytes >= 8)
- return;
- num_checked = png_ptr->sig_bytes;
- num_to_check = 8 - num_checked;
- #ifdef PNG_IO_STATE_SUPPORTED
- png_ptr->io_state = PNG_IO_READING | PNG_IO_SIGNATURE;
- #endif
- /* The signature must be serialized in a single I/O call. */
- png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check);
- png_ptr->sig_bytes = 8;
- if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
- {
- if (num_checked < 4 &&
- png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
- png_error(png_ptr, "Not a PNG file");
- else
- png_error(png_ptr, "PNG file corrupted by ASCII conversion");
- }
- if (num_checked < 3)
- png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
- }
- /* Read the chunk header (length + type name).
- * Put the type name into png_ptr->chunk_name, and return the length.
- */
- png_uint_32 /* PRIVATE */
- png_read_chunk_header(png_structp png_ptr)
- {
- png_byte buf[8];
- png_uint_32 length;
- #ifdef PNG_IO_STATE_SUPPORTED
- png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_HDR;
- #endif
- /* Read the length and the chunk name.
- * This must be performed in a single I/O call.
- */
- png_read_data(png_ptr, buf, 8);
- length = png_get_uint_31(png_ptr, buf);
- /* Put the chunk name into png_ptr->chunk_name. */
- png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(buf+4);
- png_debug2(0, "Reading %lx chunk, length = %lu",
- (unsigned long)png_ptr->chunk_name, (unsigned long)length);
- /* Reset the crc and run it over the chunk name. */
- png_reset_crc(png_ptr);
- png_calculate_crc(png_ptr, buf + 4, 4);
- /* Check to see if chunk name is valid. */
- png_check_chunk_name(png_ptr, png_ptr->chunk_name);
- #ifdef PNG_IO_STATE_SUPPORTED
- png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_DATA;
- #endif
- return length;
- }
- /* Read data, and (optionally) run it through the CRC. */
- void /* PRIVATE */
- png_crc_read(png_structp png_ptr, png_bytep buf, png_size_t length)
- {
- if (png_ptr == NULL)
- return;
- png_read_data(png_ptr, buf, length);
- png_calculate_crc(png_ptr, buf, length);
- }
- /* Optionally skip data and then check the CRC. Depending on whether we
- * are reading a ancillary or critical chunk, and how the program has set
- * things up, we may calculate the CRC on the data and print a message.
- * Returns '1' if there was a CRC error, '0' otherwise.
- */
- int /* PRIVATE */
- png_crc_finish(png_structp png_ptr, png_uint_32 skip)
- {
- png_size_t i;
- png_size_t istop = png_ptr->zbuf_size;
- for (i = (png_size_t)skip; i > istop; i -= istop)
- {
- png_crc_read(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
- }
- if (i)
- {
- png_crc_read(png_ptr, png_ptr->zbuf, i);
- }
- if (png_crc_error(png_ptr))
- {
- if (PNG_CHUNK_ANCILLIARY(png_ptr->chunk_name) ?
- !(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) :
- (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_USE))
- {
- png_chunk_warning(png_ptr, "CRC error");
- }
- else
- {
- png_chunk_benign_error(png_ptr, "CRC error");
- return (0);
- }
- return (1);
- }
- return (0);
- }
- /* Compare the CRC stored in the PNG file with that calculated by libpng from
- * the data it has read thus far.
- */
- int /* PRIVATE */
- png_crc_error(png_structp png_ptr)
- {
- png_byte crc_bytes[4];
- png_uint_32 crc;
- int need_crc = 1;
- if (PNG_CHUNK_ANCILLIARY(png_ptr->chunk_name))
- {
- if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
- (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
- need_crc = 0;
- }
- else /* critical */
- {
- if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE)
- need_crc = 0;
- }
- #ifdef PNG_IO_STATE_SUPPORTED
- png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_CRC;
- #endif
- /* The chunk CRC must be serialized in a single I/O call. */
- png_read_data(png_ptr, crc_bytes, 4);
- if (need_crc)
- {
- crc = png_get_uint_32(crc_bytes);
- return ((int)(crc != png_ptr->crc));
- }
- else
- return (0);
- }
- #ifdef PNG_READ_COMPRESSED_TEXT_SUPPORTED
- static png_size_t
- png_inflate(png_structp png_ptr, png_bytep data, png_size_t size,
- png_bytep output, png_size_t output_size)
- {
- png_size_t count = 0;
- /* zlib can't necessarily handle more than 65535 bytes at once (i.e. it can't
- * even necessarily handle 65536 bytes) because the type uInt is "16 bits or
- * more". Consequently it is necessary to chunk the input to zlib. This
- * code uses ZLIB_IO_MAX, from pngpriv.h, as the maximum (the maximum value
- * that can be stored in a uInt.) It is possible to set ZLIB_IO_MAX to a
- * lower value in pngpriv.h and this may sometimes have a performance
- * advantage, because it forces access of the input data to be separated from
- * at least some of the use by some period of time.
- */
- png_ptr->zstream.next_in = data;
- /* avail_in is set below from 'size' */
- png_ptr->zstream.avail_in = 0;
- while (1)
- {
- int ret, avail;
- /* The setting of 'avail_in' used to be outside the loop; by setting it
- * inside it is possible to chunk the input to zlib and simply rely on
- * zlib to advance the 'next_in' pointer. This allows arbitrary amounts o
- * data to be passed through zlib at the unavoidable cost of requiring a
- * window save (memcpy of up to 32768 output bytes) every ZLIB_IO_MAX
- * input bytes.
- */
- if (png_ptr->zstream.avail_in == 0 && size > 0)
- {
- if (size <= ZLIB_IO_MAX)
- {
- /* The value is less than ZLIB_IO_MAX so the cast is safe: */
- png_ptr->zstream.avail_in = (uInt)size;
- size = 0;
- }
- else
- {
- png_ptr->zstream.avail_in = ZLIB_IO_MAX;
- size -= ZLIB_IO_MAX;
- }
- }
- /* Reset the output buffer each time round - we empty it
- * after every inflate call.
- */
- png_ptr->zstream.next_out = png_ptr->zbuf;
- png_ptr->zstream.avail_out = png_ptr->zbuf_size;
- ret = inflate(&png_ptr->zstream, Z_NO_FLUSH);
- avail = png_ptr->zbuf_size - png_ptr->zstream.avail_out;
- /* First copy/count any new output - but only if we didn't
- * get an error code.
- */
- if ((ret == Z_OK || ret == Z_STREAM_END) && avail > 0)
- {
- png_size_t space = avail; /* > 0, see above */
- if (output != 0 && output_size > count)
- {
- png_size_t copy = output_size - count;
- if (space < copy)
- copy = space;
- png_memcpy(output + count, png_ptr->zbuf, copy);
- }
- count += space;
- }
- if (ret == Z_OK)
- continue;
- /* Termination conditions - always reset the zstream, it
- * must be left in inflateInit state.
- */
- png_ptr->zstream.avail_in = 0;
- inflateReset(&png_ptr->zstream);
- if (ret == Z_STREAM_END)
- return count; /* NOTE: may be zero. */
- /* Now handle the error codes - the API always returns 0
- * and the error message is dumped into the uncompressed
- * buffer if available.
- */
- # ifdef PNG_WARNINGS_SUPPORTED
- {
- png_const_charp msg;
- if (png_ptr->zstream.msg != 0)
- msg = png_ptr->zstream.msg;
- else switch (ret)
- {
- case Z_BUF_ERROR:
- msg = "Buffer error in compressed datastream";
- break;
- case Z_DATA_ERROR:
- msg = "Data error in compressed datastream";
- break;
- default:
- msg = "Incomplete compressed datastream";
- break;
- }
- png_chunk_warning(png_ptr, msg);
- }
- # endif
- /* 0 means an error - notice that this code simply ignores
- * zero length compressed chunks as a result.
- */
- return 0;
- }
- }
- /*
- * Decompress trailing data in a chunk. The assumption is that chunkdata
- * points at an allocated area holding the contents of a chunk with a
- * trailing compressed part. What we get back is an allocated area
- * holding the original prefix part and an uncompressed version of the
- * trailing part (the malloc area passed in is freed).
- */
- void /* PRIVATE */
- png_decompress_chunk(png_structp png_ptr, int comp_type,
- png_size_t chunklength,
- png_size_t prefix_size, png_size_t *newlength)
- {
- /* The caller should guarantee this */
- if (prefix_size > chunklength)
- {
- /* The recovery is to delete the chunk. */
- png_warning(png_ptr, "invalid chunklength");
- prefix_size = 0; /* To delete everything */
- }
- else if (comp_type == PNG_COMPRESSION_TYPE_BASE)
- {
- png_size_t expanded_size = png_inflate(png_ptr,
- (png_bytep)(png_ptr->chunkdata + prefix_size),
- chunklength - prefix_size,
- 0, /* output */
- 0); /* output size */
- /* Now check the limits on this chunk - if the limit fails the
- * compressed data will be removed, the prefix will remain.
- */
- if (prefix_size >= (~(png_size_t)0) - 1 ||
- expanded_size >= (~(png_size_t)0) - 1 - prefix_size
- #ifdef PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED
- || (png_ptr->user_chunk_malloc_max &&
- (prefix_size + expanded_size >= png_ptr->user_chunk_malloc_max - 1))
- #else
- # ifdef PNG_USER_CHUNK_MALLOC_MAX
- || ((PNG_USER_CHUNK_MALLOC_MAX > 0) &&
- prefix_size + expanded_size >= PNG_USER_CHUNK_MALLOC_MAX - 1)
- # endif
- #endif
- )
- png_warning(png_ptr, "Exceeded size limit while expanding chunk");
- /* If the size is zero either there was an error and a message
- * has already been output (warning) or the size really is zero
- * and we have nothing to do - the code will exit through the
- * error case below.
- */
- 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);
- 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 num, i;
- #ifdef PNG_POINTER_INDEXING_SUPPORTED
- png_colorp pal_ptr;
- #endif
- png_debug(1, "in png_handle_PLTE");
- if (!(png_ptr->mode & PNG_HAVE_IHDR))
- png_error(png_ptr, "Missing IHDR before PLTE");
- else if (png_ptr->mode & PNG_HAVE_IDAT)
- {
- png_warning(png_ptr, "Invalid PLTE after IDAT");
- png_crc_finish(png_ptr, length);
- return;
- }
- else if (png_ptr->mode & PNG_HAVE_PLTE)
- png_error(png_ptr, "Duplicate PLTE chunk");
- png_ptr->mode |= PNG_HAVE_PLTE;
- if (!(png_ptr->color_type&PNG_COLOR_MASK_COLOR))
- {
- png_warning(png_ptr,
- "Ignoring PLTE chunk in grayscale PNG");
- png_crc_finish(png_ptr, length);
- return;
- }
- #ifndef PNG_READ_OPT_PLTE_SUPPORTED
- if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
- {
- png_crc_finish(png_ptr, length);
- return;
- }
- #endif
- if (length > 3*PNG_MAX_PALETTE_LENGTH || length % 3)
- {
- if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
- {
- png_warning(png_ptr, "Invalid palette chunk");
- png_crc_finish(png_ptr, length);
- return;
- }
- else
- {
- png_error(png_ptr, "Invalid palette chunk");
- }
- }
- num = (int)length / 3;
- #ifdef PNG_POINTER_INDEXING_SUPPORTED
- for (i = 0, pal_ptr = palette; i < num; i++, pal_ptr++)
- {
- png_byte buf[3];
- png_crc_read(png_ptr, buf, 3);
- pal_ptr->red = buf[0];
- pal_ptr->green = buf[1];
- pal_ptr->blue = buf[2];
- }
- #else
- for (i = 0; i < num; i++)
- {
- png_byte buf[3];
- png_crc_read(png_ptr, buf, 3);
- /* Don't depend upon png_color being any order */
- palette[i].red = buf[0];
- palette[i].green = buf[1];
- palette[i].blue = buf[2];
- }
- #endif
- /* If we actually need the PLTE chunk (ie for a paletted image), we do
- * whatever the normal CRC configuration tells us. However, if we
- * have an RGB image, the PLTE can be considered ancillary, so
- * we will act as though it is.
- */
- #ifndef PNG_READ_OPT_PLTE_SUPPORTED
- if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
- #endif
- {
- png_crc_finish(png_ptr, 0);
- }
- #ifndef PNG_READ_OPT_PLTE_SUPPORTED
- else if (png_crc_error(png_ptr)) /* Only if we have a CRC error */
- {
- /* If we don't want to use the data from an ancillary chunk,
- * we have two options: an error abort, or a warning and we
- * ignore the data in this chunk (which should be OK, since
- * it's considered ancillary for a RGB or RGBA image).
- */
- if (!(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_USE))
- {
- if (png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN)
- {
- png_chunk_benign_error(png_ptr, "CRC error");
- }
- else
- {
- png_chunk_warning(png_ptr, "CRC error");
- return;
- }
- }
- /* Otherwise, we (optionally) emit a warning and use the chunk. */
- else if (!(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN))
- {
- png_chunk_warning(png_ptr, "CRC error");
- }
- }
- #endif
- png_set_PLTE(png_ptr, info_ptr, palette, num);
- #ifdef PNG_READ_tRNS_SUPPORTED
- if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
- {
- if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS))
- {
- if (png_ptr->num_trans > (png_uint_16)num)
- {
- png_warning(png_ptr, "Truncating incorrect tRNS chunk length");
- png_ptr->num_trans = (png_uint_16)num;
- }
- if (info_ptr->num_trans > (png_uint_16)num)
- {
- png_warning(png_ptr, "Truncating incorrect info tRNS chunk length");
- info_ptr->num_trans = (png_uint_16)num;
- }
- }
- }
- #endif
- }
- void /* PRIVATE */
- png_handle_IEND(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
- {
- png_debug(1, "in png_handle_IEND");
- if (!(png_ptr->mode & PNG_HAVE_IHDR) || !(png_ptr->mode & PNG_HAVE_IDAT))
- {
- png_error(png_ptr, "No image in file");
- }
- png_ptr->mode |= (PNG_AFTER_IDAT | PNG_HAVE_IEND);
- if (length != 0)
- {
- png_warning(png_ptr, "Incorrect IEND chunk length");
- }
- png_crc_finish(png_ptr, length);
- PNG_UNUSED(info_ptr) /* Quiet compiler warnings about unused info_ptr */
- }
- #ifdef PNG_READ_gAMA_SUPPORTED
- void /* PRIVATE */
- png_handle_gAMA(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
- {
- png_fixed_point igamma;
- png_byte buf[4];
- png_debug(1, "in png_handle_gAMA");
- if (!(png_ptr->mode & PNG_HAVE_IHDR))
- png_error(png_ptr, "Missing IHDR before gAMA");
- else if (png_ptr->mode & PNG_HAVE_IDAT)
- {
- png_warning(png_ptr, "Invalid gAMA after IDAT");
- png_crc_finish(png_ptr, length);
- return;
- }
- else if (png_ptr->mode & PNG_HAVE_PLTE)
- /* Should be an error, but we can cope with it */
- png_warning(png_ptr, "Out of place gAMA chunk");
- if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_gAMA)
- #ifdef PNG_READ_sRGB_SUPPORTED
- && !(info_ptr->valid & PNG_INFO_sRGB)
- #endif
- )
- {
- png_warning(png_ptr, "Duplicate gAMA chunk");
- png_crc_finish(png_ptr, length);
- return;
- }
- if (length != 4)
- {
- png_warning(png_ptr, "Incorrect gAMA chunk length");
- png_crc_finish(png_ptr, length);
- return;
- }
- png_crc_read(png_ptr, buf, 4);
- if (png_crc_finish(png_ptr, 0))
- return;
- igamma = png_get_fixed_point(NULL, buf);
- /* Check for zero gamma or an error. */
- if (igamma <= 0)
- {
- png_warning(png_ptr,
- "Ignoring gAMA chunk with out of range gamma");
- return;
- }
- # ifdef PNG_READ_sRGB_SUPPORTED
- if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sRGB))
- {
- if (PNG_OUT_OF_RANGE(igamma, 45500, 500))
- {
- PNG_WARNING_PARAMETERS(p)
- png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_fixed, igamma);
- png_formatted_warning(png_ptr, p,
- "Ignoring incorrect gAMA value @1 when sRGB is also present");
- return;
- }
- }
- # endif /* PNG_READ_sRGB_SUPPORTED */
- # ifdef PNG_READ_GAMMA_SUPPORTED
- /* Gamma correction on read is supported. */
- png_ptr->gamma = igamma;
- # endif
- /* And set the 'info' structure members. */
- png_set_gAMA_fixed(png_ptr, info_ptr, igamma);
- }
- #endif
- #ifdef PNG_READ_sBIT_SUPPORTED
- void /* PRIVATE */
- png_handle_sBIT(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
- {
- png_size_t truelen;
- png_byte buf[4];
- png_debug(1, "in png_handle_sBIT");
- buf[0] = buf[1] = buf[2] = buf[3] = 0;
- if (!(png_ptr->mode & PNG_HAVE_IHDR))
- png_error(png_ptr, "Missing IHDR before sBIT");
- else if (png_ptr->mode & PNG_HAVE_IDAT)
- {
- png_warning(png_ptr, "Invalid sBIT after IDAT");
- png_crc_finish(png_ptr, length);
- return;
- }
- else if (png_ptr->mode & PNG_HAVE_PLTE)
- {
- /* Should be an error, but we can cope with it */
- png_warning(png_ptr, "Out of place sBIT chunk");
- }
- if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT))
- {
- png_warning(png_ptr, "Duplicate sBIT chunk");
- png_crc_finish(png_ptr, length);
- return;
- }
- if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
- truelen = 3;
- else
- truelen = (png_size_t)png_ptr->channels;
- if (length != truelen || length > 4)
- {
- png_warning(png_ptr, "Incorrect sBIT chunk length");
- png_crc_finish(png_ptr, length);
- return;
- }
- png_crc_read(png_ptr, buf, truelen);
- if (png_crc_finish(png_ptr, 0))
- return;
- if (png_ptr->color_type & PNG_COLOR_MASK_COLOR)
- {
- png_ptr->sig_bit.red = buf[0];
- png_ptr->sig_bit.green = buf[1];
- png_ptr->sig_bit.blue = buf[2];
- png_ptr->sig_bit.alpha = buf[3];
- }
- else
- {
- png_ptr->sig_bit.gray = buf[0];
- png_ptr->sig_bit.red = buf[0];
- png_ptr->sig_bit.green = buf[0];
- png_ptr->sig_bit.blue = buf[0];
- png_ptr->sig_bit.alpha = buf[1];
- }
- png_set_sBIT(png_ptr, info_ptr, &(png_ptr->sig_bit));
- }
- #endif
- #ifdef PNG_READ_cHRM_SUPPORTED
- void /* PRIVATE */
- png_handle_cHRM(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
- {
- png_byte buf[32];
- png_fixed_point x_white, y_white, x_red, y_red, x_green, y_green, x_blue,
- y_blue;
- png_debug(1, "in png_handle_cHRM");
- if (!(png_ptr->mode & PNG_HAVE_IHDR))
- png_error(png_ptr, "Missing IHDR before cHRM");
- else if (png_ptr->mode & PNG_HAVE_IDAT)
- {
- png_warning(png_ptr, "Invalid cHRM after IDAT");
- png_crc_finish(png_ptr, length);
- return;
- }
- else if (png_ptr->mode & PNG_HAVE_PLTE)
- /* Should be an error, but we can cope with it */
- png_warning(png_ptr, "Out of place cHRM chunk");
- if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_cHRM)
- # ifdef PNG_READ_sRGB_SUPPORTED
- && !(info_ptr->valid & PNG_INFO_sRGB)
- # endif
- )
- {
- png_warning(png_ptr, "Duplicate cHRM chunk");
- png_crc_finish(png_ptr, length);
- return;
- }
- if (length != 32)
- {
- png_warning(png_ptr, "Incorrect cHRM chunk length");
- png_crc_finish(png_ptr, length);
- return;
- }
- png_crc_read(png_ptr, buf, 32);
- if (png_crc_finish(png_ptr, 0))
- return;
- x_white = png_get_fixed_point(NULL, buf);
- y_white = png_get_fixed_point(NULL, buf + 4);
- x_red = png_get_fixed_point(NULL, buf + 8);
- y_red = png_get_fixed_point(NULL, buf + 12);
- x_green = png_get_fixed_point(NULL, buf + 16);
- y_green = png_get_fixed_point(NULL, buf + 20);
- x_blue = png_get_fixed_point(NULL, buf + 24);
- y_blue = png_get_fixed_point(NULL, buf + 28);
- if (x_white == PNG_FIXED_ERROR ||
- y_white == PNG_FIXED_ERROR ||
- x_red == PNG_FIXED_ERROR ||
- y_red == PNG_FIXED_ERROR ||
- x_green == PNG_FIXED_ERROR ||
- y_green == PNG_FIXED_ERROR ||
- x_blue == PNG_FIXED_ERROR ||
- y_blue == PNG_FIXED_ERROR)
- {
- png_warning(png_ptr, "Ignoring cHRM chunk with negative chromaticities");
- return;
- }
- #ifdef PNG_READ_sRGB_SUPPORTED
- if ((info_ptr != NULL) && (info_ptr->valid & PNG_INFO_sRGB))
- {
- if (PNG_OUT_OF_RANGE(x_white, 31270, 1000) ||
- PNG_OUT_OF_RANGE(y_white, 32900, 1000) ||
- PNG_OUT_OF_RANGE(x_red, 64000, 1000) ||
- PNG_OUT_OF_RANGE(y_red, 33000, 1000) ||
- PNG_OUT_OF_RANGE(x_green, 30000, 1000) ||
- PNG_OUT_OF_RANGE(y_green, 60000, 1000) ||
- PNG_OUT_OF_RANGE(x_blue, 15000, 1000) ||
- PNG_OUT_OF_RANGE(y_blue, 6000, 1000))
- {
- PNG_WARNING_PARAMETERS(p)
- png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_fixed, x_white);
- png_warning_parameter_signed(p, 2, PNG_NUMBER_FORMAT_fixed, y_white);
- png_warning_parameter_signed(p, 3, PNG_NUMBER_FORMAT_fixed, x_red);
- png_warning_parameter_signed(p, 4, PNG_NUMBER_FORMAT_fixed, y_red);
- png_warning_parameter_signed(p, 5, PNG_NUMBER_FORMAT_fixed, x_green);
- png_warning_parameter_signed(p, 6, PNG_NUMBER_FORMAT_fixed, y_green);
- png_warning_parameter_signed(p, 7, PNG_NUMBER_FORMAT_fixed, x_blue);
- png_warning_parameter_signed(p, 8, PNG_NUMBER_FORMAT_fixed, y_blue);
- png_formatted_warning(png_ptr, p,
- "Ignoring incorrect cHRM white(@1,@2) r(@3,@4)g(@5,@6)b(@7,@8) "
- "when sRGB is also present");
- }
- return;
- }
- #endif /* PNG_READ_sRGB_SUPPORTED */
- #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
- /* Store the _white values as default coefficients for the rgb to gray
- * operation if it is supported. Check if the transform is already set to
- * avoid destroying the transform values.
- */
- if (!png_ptr->rgb_to_gray_coefficients_set)
- {
- /* png_set_background has not been called and we haven't seen an sRGB
- * chunk yet. Find the XYZ of the three end points.
- */
- png_XYZ XYZ;
- png_xy xy;
- xy.redx = x_red;
- xy.redy = y_red;
- xy.greenx = x_green;
- xy.greeny = y_green;
- xy.bluex = x_blue;
- xy.bluey = y_blue;
- xy.whitex = x_white;
- xy.whitey = y_white;
- if (png_XYZ_from_xy_checked(png_ptr, &XYZ, xy))
- {
- /* The success case, because XYZ_from_xy normalises to a reference
- * white Y of 1.0 we just need to scale the numbers. This should
- * always work just fine. It is an internal error if this overflows.
- */
- {
- png_fixed_point r, g, b;
- if (png_muldiv(&r, XYZ.redY, 32768, PNG_FP_1) &&
- r >= 0 && r <= 32768 &&
- png_muldiv(&g, XYZ.greenY, 32768, PNG_FP_1) &&
- g >= 0 && g <= 32768 &&
- png_muldiv(&b, XYZ.blueY, 32768, PNG_FP_1) &&
- b >= 0 && b <= 32768 &&
- r+g+b <= 32769)
- {
- /* We allow 0 coefficients here. r+g+b may be 32769 if two or
- * all of the coefficients were rounded up. Handle this by
- * reducing the *largest* coefficient by 1; this matches the
- * approach used for the default coefficients in pngrtran.c
- */
- int add = 0;
- if (r+g+b > 32768)
- add = -1;
- else if (r+g+b < 32768)
- add = 1;
- if (add != 0)
- {
- if (g >= r && g >= b)
- g += add;
- else if (r >= g && r >= b)
- r += add;
- else
- b += add;
- }
- /* Check for an internal error. */
- if (r+g+b != 32768)
- png_error(png_ptr,
- "internal error handling cHRM coefficients");
- png_ptr->rgb_to_gray_red_coeff = (png_uint_16)r;
- png_ptr->rgb_to_gray_green_coeff = (png_uint_16)g;
- }
- /* This is a png_error at present even though it could be ignored -
- * it should never happen, but it is important that if it does, the
- * bug is fixed.
- */
- else
- png_error(png_ptr, "internal error handling cHRM->XYZ");
- }
- }
- }
- #endif
- png_set_cHRM_fixed(png_ptr, info_ptr, x_white, y_white, x_red, y_red,
- x_green, y_green, x_blue, y_blue);
- }
- #endif
- #ifdef PNG_READ_sRGB_SUPPORTED
- void /* PRIVATE */
- png_handle_sRGB(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
- {
- int intent;
- png_byte buf[1];
- png_debug(1, "in png_handle_sRGB");
- if (!(png_ptr->mode & PNG_HAVE_IHDR))
- png_error(png_ptr, "Missing IHDR before sRGB");
- else if (png_ptr->mode & PNG_HAVE_IDAT)
- {
- png_warning(png_ptr, "Invalid sRGB after IDAT");
- png_crc_finish(png_ptr, length);
- return;
- }
- else if (png_ptr->mode & PNG_HAVE_PLTE)
- /* Should be an error, but we can cope with it */
- png_warning(png_ptr, "Out of place sRGB chunk");
- if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sRGB))
- {
- png_warning(png_ptr, "Duplicate sRGB chunk");
- png_crc_finish(png_ptr, length);
- return;
- }
- if (length != 1)
- {
- png_warning(png_ptr, "Incorrect sRGB chunk length");
- png_crc_finish(png_ptr, length);
- return;
- }
- png_crc_read(png_ptr, buf, 1);
- if (png_crc_finish(png_ptr, 0))
- return;
- intent = buf[0];
- /* Check for bad intent */
- if (intent >= PNG_sRGB_INTENT_LAST)
- {
- png_warning(png_ptr, "Unknown sRGB intent");
- return;
- }
- #if defined(PNG_READ_gAMA_SUPPORTED) && defined(PNG_READ_GAMMA_SUPPORTED)
- if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_gAMA))
- {
- if (PNG_OUT_OF_RANGE(info_ptr->gamma, 45500, 500))
- {
- PNG_WARNING_PARAMETERS(p)
- png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_fixed,
- info_ptr->gamma);
- png_formatted_warning(png_ptr, p,
- "Ignoring incorrect gAMA value @1 when sRGB is also present");
- }
- }
- #endif /* PNG_READ_gAMA_SUPPORTED */
- #ifdef PNG_READ_cHRM_SUPPORTED
- if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_cHRM))
- if (PNG_OUT_OF_RANGE(info_ptr->x_white, 31270, 1000) ||
- PNG_OUT_OF_RANGE(info_ptr->y_white, 32900, 1000) ||
- PNG_OUT_OF_RANGE(info_ptr->x_red, 64000, 1000) ||
- PNG_OUT_OF_RANGE(info_ptr->y_red, 33000, 1000) ||
- PNG_OUT_OF_RANGE(info_ptr->x_green, 30000, 1000) ||
- PNG_OUT_OF_RANGE(info_ptr->y_green, 60000, 1000) ||
- PNG_OUT_OF_RANGE(info_ptr->x_blue, 15000, 1000) ||
- PNG_OUT_OF_RANGE(info_ptr->y_blue, 6000, 1000))
- {
- png_warning(png_ptr,
- "Ignoring incorrect cHRM value when sRGB is also present");
- }
- #endif /* PNG_READ_cHRM_SUPPORTED */
- /* This is recorded for use when handling the cHRM chunk above. An sRGB
- * chunk unconditionally overwrites the coefficients for grayscale conversion
- * too.
- */
- png_ptr->is_sRGB = 1;
- # ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
- /* Don't overwrite user supplied values: */
- if (!png_ptr->rgb_to_gray_coefficients_set)
- {
- /* These numbers come from the sRGB specification (or, since one has to
- * pay much money to get a copy, the wikipedia sRGB page) the
- * chromaticity values quoted have been inverted to get the reverse
- * transformation from RGB to XYZ and the 'Y' coefficients scaled by
- * 32768 (then rounded).
- *
- * sRGB and ITU Rec-709 both truncate the values for the D65 white
- * point to four digits and, even though it actually stores five
- * digits, the PNG spec gives the truncated value.
- *
- * This means that when the chromaticities are converted back to XYZ
- * end points we end up with (6968,23435,2366), which, as described in
- * pngrtran.c, would overflow. If the five digit precision and up is
- * used we get, instead:
- *
- * 6968*R + 23435*G + 2365*B
- *
- * (Notice that this rounds the blue coefficient down, rather than the
- * choice used in pngrtran.c which is to round the green one down.)
- */
- png_ptr->rgb_to_gray_red_coeff = 6968; /* 0.212639005871510 */
- png_ptr->rgb_to_gray_green_coeff = 23434; /* 0.715168678767756 */
- /* png_ptr->rgb_to_gray_blue_coeff = 2366; 0.072192315360734 */
- /* The following keeps the cHRM chunk from destroying the
- * coefficients again in the event that it follows the sRGB chunk.
- */
- png_ptr->rgb_to_gray_coefficients_set = 1;
- }
- # endif
- png_set_sRGB_gAMA_and_cHRM(png_ptr, info_ptr, intent);
- }
- #endif /* PNG_READ_sRGB_SUPPORTED */
- #ifdef PNG_READ_iCCP_SUPPORTED
- void /* PRIVATE */
- png_handle_iCCP(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
- /* Note: this does not properly handle chunks that are > 64K under DOS */
- {
- png_byte compression_type;
- png_bytep pC;
- png_charp profile;
- png_uint_32 skip = 0;
- png_uint_32 profile_size;
- png_alloc_size_t profile_length;
- png_size_t slength, prefix_length, data_length;
- png_debug(1, "in png_handle_iCCP");
- if (!(png_ptr->mode & PNG_HAVE_IHDR))
- png_error(png_ptr, "Missing IHDR before iCCP");
- else if (png_ptr->mode & PNG_HAVE_IDAT)
- {
- png_warning(png_ptr, "Invalid iCCP after IDAT");
- png_crc_finish(png_ptr, length);
- return;
- }
- else if (png_ptr->mode & PNG_HAVE_PLTE)
- /* Should be an error, but we can cope with it */
- png_warning(png_ptr, "Out of place iCCP chunk");
- if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_iCCP))
- {
- png_warning(png_ptr, "Duplicate iCCP chunk");
- png_crc_finish(png_ptr, length);
- return;
- }
- #ifdef PNG_MAX_MALLOC_64K
- if (length > (png_uint_32)65535L)
- {
- png_warning(png_ptr, "iCCP chunk too large to fit in memory");
- skip = length - (png_uint_32)65535L;
- length = (png_uint_32)65535L;
- }
- #endif
- png_free(png_ptr, png_ptr->chunkdata);
- png_ptr->chunkdata = (png_charp)png_malloc(png_ptr, length + 1);
- slength = length;
- png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength);
- if (png_crc_finish(png_ptr, skip))
- {
- png_free(png_ptr, png_ptr->chunkdata);
- png_ptr->chunkdata = NULL;
- return;
- }
- png_ptr->chunkdata[slength] = 0x00;
- for (profile = png_ptr->chunkdata; *profile; profile++)
- /* Empty loop to find end of name */ ;
- ++profile;
- /* There should be at least one zero (the compression type byte)
- * following the separator, and we should be on it
- */
- if (profile >= png_ptr->chunkdata + slength - 1)
- {
- png_free(png_ptr, png_ptr->chunkdata);
- png_ptr->chunkdata = NULL;
- png_warning(png_ptr, "Malformed iCCP chunk");
- return;
- }
- /* Compression_type should always be zero */
- compression_type = *profile++;
- if (compression_type)
- {
- png_warning(png_ptr, "Ignoring nonzero compression type in iCCP chunk");
- compression_type = 0x00; /* Reset it to zero (libpng-1.0.6 through 1.0.8
- wrote nonzero) */
- }
- prefix_length = profile - png_ptr->chunkdata;
- png_decompress_chunk(png_ptr, compression_type,
- slength, prefix_length, &data_length);
- profile_length = data_length - prefix_length;
- if (prefix_length > data_length || profile_length < 4)
- {
- png_free(png_ptr, png_ptr->chunkdata);
- png_ptr->chunkdata = NULL;
- png_warning(png_ptr, "Profile size field missing from iCCP chunk");
- return;
- }
- /* Check the profile_size recorded in the first 32 bits of the ICC profile */
- pC = (png_bytep)(png_ptr->chunkdata + prefix_length);
- profile_size = ((*(pC )) << 24) |
- ((*(pC + 1)) << 16) |
- ((*(pC + 2)) << 8) |
- ((*(pC + 3)) );
- /* NOTE: the following guarantees that 'profile_length' fits into 32 bits,
- * because profile_size is a 32 bit value.
- */
- if (profile_size < profile_length)
- profile_length = profile_size;
- /* And the following guarantees that profile_size == profile_length. */
- if (profile_size > profile_length)
- {
- PNG_WARNING_PARAMETERS(p)
- png_free(png_ptr, png_ptr->chunkdata);
- png_ptr->chunkdata = NULL;
- png_warning_parameter_unsigned(p, 1, PNG_NUMBER_FORMAT_u, profile_size);
- png_warning_parameter_unsigned(p, 2, PNG_NUMBER_FORMAT_u, profile_length);
- png_formatted_warning(png_ptr, p,
- "Ignoring iCCP chunk with declared size = @1 and actual length = @2");
- return;
- }
- png_set_iCCP(png_ptr, info_ptr, png_ptr->chunkdata,
- compression_type, (png_bytep)png_ptr->chunkdata + prefix_length,
- profile_size);
- png_free(png_ptr, png_ptr->chunkdata);
- png_ptr->chunkdata = NULL;
- }
- #endif /* PNG_READ_iCCP_SUPPORTED */
- #ifdef PNG_READ_sPLT_SUPPORTED
- void /* PRIVATE */
- png_handle_sPLT(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
- /* Note: this does not properly handle chunks that are > 64K under DOS */
- {
- png_bytep entry_start;
- png_sPLT_t new_palette;
- png_sPLT_entryp pp;
- png_uint_32 data_length;
- int entry_size, i;
- png_uint_32 skip = 0;
- png_size_t slength;
- png_uint_32 dl;
- png_size_t max_dl;
- png_debug(1, "in png_handle_sPLT");
- #ifdef PNG_USER_LIMITS_SUPPORTED
- if (png_ptr->user_chunk_cache_max != 0)
- {
- if (png_ptr->user_chunk_cache_max == 1)
- {
- png_crc_finish(png_ptr, length);
- return;
- }
- if (--png_ptr->user_chunk_cache_max == 1)
- {
- png_warning(png_ptr, "No space in chunk cache for sPLT");
- png_crc_finish(png_ptr, length);
- return;
- }
- }
- #endif
- if (!(png_ptr->mode & PNG_HAVE_IHDR))
- png_error(png_ptr, "Missing IHDR before sPLT");
- else if (png_ptr->mode & PNG_HAVE_IDAT)
- {
- png_warning(png_ptr, "Invalid sPLT after IDAT");
- png_crc_finish(png_ptr, length);
- return;
- }
- #ifdef PNG_MAX_MALLOC_64K
- if (length > (png_uint_32)65535L)
- {
- png_warning(png_ptr, "sPLT chunk too large to fit in memory");
- skip = length - (png_uint_32)65535L;
- length = (png_uint_32)65535L;
- }
- #endif
- png_free(png_ptr, png_ptr->chunkdata);
- png_ptr->chunkdata = (png_charp)png_malloc(png_ptr, length + 1);
- /* WARNING: this may break if size_t is less than 32 bits; it is assumed
- * that the PNG_MAX_MALLOC_64K test is enabled in this case, but this is a
- * potential breakage point if the types in pngconf.h aren't exactly right.
- */
- slength = length;
- png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength);
- if (png_crc_finish(png_ptr, skip))
- {
- png_free(png_ptr, png_ptr->chunkdata);
- png_ptr->chunkdata = NULL;
- return;
- }
- png_ptr->chunkdata[slength] = 0x00;
- for (entry_start = (png_bytep)png_ptr->chunkdata; *entry_start;
- entry_start++)
- /* Empty loop to find end of name */ ;
- ++entry_start;
- /* A sample depth should follow the separator, and we should be on it */
- if (entry_start > (png_bytep)png_ptr->chunkdata + slength - 2)
- {
- png_free(png_ptr, png_ptr->chunkdata);
- png_ptr->chunkdata = NULL;
- png_warning(png_ptr, "malformed sPLT chunk");
- return;
- }
- new_palette.depth = *entry_start++;
- entry_size = (new_palette.depth == 8 ? 6 : 10);
- /* This must fit in a png_uint_32 because it is derived from the original
- * chunk data length (and use 'length', not 'slength' here for clarity -
- * they are guaranteed to be the same, see the tests above.)
- */
- data_length = length - (png_uint_32)(entry_start -
- (png_bytep)png_ptr->chunkdata);
- /* Integrity-check the data length */
- if (data_length % entry_size)
- {
- png_free(png_ptr, png_ptr->chunkdata);
- png_ptr->chunkdata = NULL;
- png_warning(png_ptr, "sPLT chunk has bad length");
- return;
- }
- dl = (png_int_32)(data_length / entry_size);
- max_dl = PNG_SIZE_MAX / png_sizeof(png_sPLT_entry);
- if (dl > max_dl)
- {
- png_warning(png_ptr, "sPLT chunk too long");
- return;
- }
- new_palette.nentries = (png_int_32)(data_length / entry_size);
- new_palette.entries = (png_sPLT_entryp)png_malloc_warn(
- png_ptr, new_palette.nentries * png_sizeof(png_sPLT_entry));
- if (new_palette.entries == NULL)
- {
- png_warning(png_ptr, "sPLT chunk requires too much memory");
- return;
- }
- #ifdef PNG_POINTER_INDEXING_SUPPORTED
- for (i = 0; i < new_palette.nentries; i++)
- {
- pp = new_palette.entries + i;
- if (new_palette.depth == 8)
- {
- pp->red = *entry_start++;
- pp->green = *entry_start++;
- pp->blue = *entry_start++;
- pp->alpha = *entry_start++;
- }
- else
- {
- pp->red = png_get_uint_16(entry_start); entry_start += 2;
- pp->green = png_get_uint_16(entry_start); entry_start += 2;
- pp->blue = png_get_uint_16(entry_start); entry_start += 2;
- pp->alpha = png_get_uint_16(entry_start); entry_start += 2;
- }
- pp->frequency = png_get_uint_16(entry_start); entry_start += 2;
- }
- #else
- pp = new_palette.entries;
- for (i = 0; i < new_palette.nentries; i++)
- {
- if (new_palette.depth == 8)
- {
- pp[i].red = *entry_start++;
- pp[i].green = *entry_start++;
- pp[i].blue = *entry_start++;
- pp[i].alpha = *entry_start++;
- }
- else
- {
- pp[i].red = png_get_uint_16(entry_start); entry_start += 2;
- pp[i].green = png_get_uint_16(entry_start); entry_start += 2;
- pp[i].blue = png_get_uint_16(entry_start); entry_start += 2;
- pp[i].alpha = png_get_uint_16(entry_start); entry_start += 2;
- }
- pp[i].frequency = png_get_uint_16(entry_start); entry_start += 2;
- }
- #endif
- /* Discard all chunk data except the name and stash that */
- new_palette.name = png_ptr->chunkdata;
- png_set_sPLT(png_ptr, info_ptr, &new_palette, 1);
- png_free(png_ptr, png_ptr->chunkdata);
- png_ptr->chunkdata = NULL;
- png_free(png_ptr, new_palette.entries);
- }
- #endif /* PNG_READ_sPLT_SUPPORTED */
- #ifdef PNG_READ_tRNS_SUPPORTED
- void /* PRIVATE */
- png_handle_tRNS(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
- {
- png_byte readbuf[PNG_MAX_PALETTE_LENGTH];
- png_debug(1, "in png_handle_tRNS");
- if (!(png_ptr->mode & PNG_HAVE_IHDR))
- png_error(png_ptr, "Missing IHDR before tRNS");
- else if (png_ptr->mode & PNG_HAVE_IDAT)
- {
- png_warning(png_ptr, "Invalid tRNS after IDAT");
- png_crc_finish(png_ptr, length);
- return;
- }
- else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS))
- {
- png_warning(png_ptr, "Duplicate tRNS chunk");
- png_crc_finish(png_ptr, length);
- return;
- }
- if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
- {
- png_byte buf[2];
- if (length != 2)
- {
- png_warning(png_ptr, "Incorrect tRNS chunk length");
- png_crc_finish(png_ptr, length);
- return;
- }
- png_crc_read(png_ptr, buf, 2);
- png_ptr->num_trans = 1;
- png_ptr->trans_color.gray = png_get_uint_16(buf);
- }
- else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
- {
- png_byte buf[6];
- if (length != 6)
- {
- png_warning(png_ptr, "Incorrect tRNS chunk length");
- png_crc_finish(png_ptr, length);
- return;
- }
- png_crc_read(png_ptr, buf, (png_size_t)length);
- png_ptr->num_trans = 1;
- png_ptr->trans_color.red = png_get_uint_16(buf);
- png_ptr->trans_color.green = png_get_uint_16(buf + 2);
- png_ptr->trans_color.blue = png_get_uint_16(buf + 4);
- }
- else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
- {
- if (!(png_ptr->mode & PNG_HAVE_PLTE))
- {
- /* Should be an error, but we can cope with it. */
- png_warning(png_ptr, "Missing PLTE before tRNS");
- }
- if (length > (png_uint_32)png_ptr->num_palette ||
- length > PNG_MAX_PALETTE_LENGTH)
- {
- png_warning(png_ptr, "Incorrect tRNS chunk length");
- png_crc_finish(png_ptr, length);
- return;
- }
- if (length == 0)
- {
- png_warning(png_ptr, "Zero length tRNS chunk");
- png_crc_finish(png_ptr, length);
- return;
- }
- png_crc_read(png_ptr, readbuf, (png_size_t)length);
- png_ptr->num_trans = (png_uint_16)length;
- }
- else
- {
- png_warning(png_ptr, "tRNS chunk not allowed with alpha channel");
- png_crc_finish(png_ptr, length);
- return;
- }
- if (png_crc_finish(png_ptr, 0))
- {
- png_ptr->num_trans = 0;
- return;
- }
- png_set_tRNS(png_ptr, info_ptr, readbuf, png_ptr->num_trans,
- &(png_ptr->trans_color));
- }
- #endif
- #ifdef PNG_READ_bKGD_SUPPORTED
- void /* PRIVATE */
- png_handle_bKGD(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
- {
- png_size_t truelen;
- png_byte buf[6];
- png_color_16 background;
- png_debug(1, "in png_handle_bKGD");
- if (!(png_ptr->mode & PNG_HAVE_IHDR))
- png_error(png_ptr, "Missing IHDR before bKGD");
- else if (png_ptr->mode & PNG_HAVE_IDAT)
- {
- png_warning(png_ptr, "Invalid bKGD after IDAT");
- png_crc_finish(png_ptr, length);
- return;
- }
- else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
- !(png_ptr->mode & PNG_HAVE_PLTE))
- {
- png_warning(png_ptr, "Missing PLTE before bKGD");
- png_crc_finish(png_ptr, length);
- return;
- }
- else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD))
- {
- png_warning(png_ptr, "Duplicate bKGD chunk");
- png_crc_finish(png_ptr, length);…