/* pngrutil.c - utilities to read a PNG file * * Last changed in libpng 1.5.6 [(PENDING RELEASE)] * Copyright (c) 1998-2011 Glenn Randers-Pehrson * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) * * This code is released under the libpng license. * For conditions of distribution and use, see the disclaimer * and license in png.h * * This file contains routines that are only called from within * libpng itself during the course of reading an image. */ #include "pngpriv.h" #ifdef PNG_READ_SUPPORTED #define png_strtod(p,a,b) strtod(a,b) png_uint_32 PNGAPI png_get_uint_31(png_structp png_ptr, png_const_bytep buf) { png_uint_32 uval = png_get_uint_32(buf); if (uval > PNG_UINT_31_MAX) png_error(png_ptr, "PNG unsigned integer out of range"); return (uval); } #if defined(PNG_READ_gAMA_SUPPORTED) || defined(PNG_READ_cHRM_SUPPORTED) /* The following is a variation on the above for use with the fixed * point values used for gAMA and cHRM. Instead of png_error it * issues a warning and returns (-1) - an invalid value because both * gAMA and cHRM use *unsigned* integers for fixed point values. */ #define PNG_FIXED_ERROR (-1) static png_fixed_point /* PRIVATE */ png_get_fixed_point(png_structp png_ptr, png_const_bytep buf) { png_uint_32 uval = png_get_uint_32(buf); if (uval <= PNG_UINT_31_MAX) return (png_fixed_point)uval; /* known to be in range */ /* The caller can turn off the warning by passing NULL. */ if (png_ptr != NULL) png_warning(png_ptr, "PNG fixed point integer out of range"); return PNG_FIXED_ERROR; } #endif #ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED /* NOTE: the read macros will obscure these definitions, so that if * PNG_USE_READ_MACROS is set the library will not use them internally, * but the APIs will still be available externally. * * The parentheses around "PNGAPI function_name" in the following three * functions are necessary because they allow the macros to co-exist with * these (unused but exported) functions. */ /* Grab an unsigned 32-bit integer from a buffer in big-endian format. */ png_uint_32 (PNGAPI png_get_uint_32)(png_const_bytep buf) { png_uint_32 uval = ((png_uint_32)(*(buf )) << 24) + ((png_uint_32)(*(buf + 1)) << 16) + ((png_uint_32)(*(buf + 2)) << 8) + ((png_uint_32)(*(buf + 3)) ) ; return uval; } /* Grab a signed 32-bit integer from a buffer in big-endian format. The * data is stored in the PNG file in two's complement format and there * is no guarantee that a 'png_int_32' is exactly 32 bits, therefore * the following code does a two's complement to native conversion. */ png_int_32 (PNGAPI png_get_int_32)(png_const_bytep buf) { png_uint_32 uval = png_get_uint_32(buf); if ((uval & 0x80000000) == 0) /* non-negative */ return uval; uval = (uval ^ 0xffffffff) + 1; /* 2's complement: -x = ~x+1 */ return -(png_int_32)uval; } /* Grab an unsigned 16-bit integer from a buffer in big-endian format. */ png_uint_16 (PNGAPI png_get_uint_16)(png_const_bytep buf) { /* ANSI-C requires an int value to accomodate at least 16 bits so this * works and allows the compiler not to worry about possible narrowing * on 32 bit systems. (Pre-ANSI systems did not make integers smaller * than 16 bits either.) */ unsigned int val = ((unsigned int)(*buf) << 8) + ((unsigned int)(*(buf + 1))); return (png_uint_16)val; } #endif /* PNG_READ_INT_FUNCTIONS_SUPPORTED */ /* Read and check the PNG file signature */ void /* PRIVATE */ png_read_sig(png_structp png_ptr, png_infop info_ptr) { png_size_t num_checked, num_to_check; /* Exit if the user application does not expect a signature. */ if (png_ptr->sig_bytes >= 8) return; num_checked = png_ptr->sig_bytes; num_to_check = 8 - num_checked; #ifdef PNG_IO_STATE_SUPPORTED png_ptr->io_state = PNG_IO_READING | PNG_IO_SIGNATURE; #endif /* The signature must be serialized in a single I/O call. */ png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check); png_ptr->sig_bytes = 8; if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check)) { if (num_checked < 4 && png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4)) png_error(png_ptr, "Not a PNG file"); else png_error(png_ptr, "PNG file corrupted by ASCII conversion"); } if (num_checked < 3) png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE; } /* Read the chunk header (length + type name). * Put the type name into png_ptr->chunk_name, and return the length. */ png_uint_32 /* PRIVATE */ png_read_chunk_header(png_structp png_ptr) { png_byte buf[8]; png_uint_32 length; #ifdef PNG_IO_STATE_SUPPORTED png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_HDR; #endif /* Read the length and the chunk name. * This must be performed in a single I/O call. */ png_read_data(png_ptr, buf, 8); length = png_get_uint_31(png_ptr, buf); /* Put the chunk name into png_ptr->chunk_name. */ png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(buf+4); png_debug2(0, "Reading %lx chunk, length = %lu", (unsigned long)png_ptr->chunk_name, (unsigned long)length); /* Reset the crc and run it over the chunk name. */ png_reset_crc(png_ptr); png_calculate_crc(png_ptr, buf + 4, 4); /* Check to see if chunk name is valid. */ png_check_chunk_name(png_ptr, png_ptr->chunk_name); #ifdef PNG_IO_STATE_SUPPORTED png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_DATA; #endif return length; } /* Read data, and (optionally) run it through the CRC. */ void /* PRIVATE */ png_crc_read(png_structp png_ptr, png_bytep buf, png_size_t length) { if (png_ptr == NULL) return; png_read_data(png_ptr, buf, length); png_calculate_crc(png_ptr, buf, length); } /* Optionally skip data and then check the CRC. Depending on whether we * are reading a ancillary or critical chunk, and how the program has set * things up, we may calculate the CRC on the data and print a message. * Returns '1' if there was a CRC error, '0' otherwise. */ int /* PRIVATE */ png_crc_finish(png_structp png_ptr, png_uint_32 skip) { png_size_t i; png_size_t istop = png_ptr->zbuf_size; for (i = (png_size_t)skip; i > istop; i -= istop) { png_crc_read(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size); } if (i) { png_crc_read(png_ptr, png_ptr->zbuf, i); } if (png_crc_error(png_ptr)) { if (PNG_CHUNK_ANCILLIARY(png_ptr->chunk_name) ? !(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) : (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_USE)) { png_chunk_warning(png_ptr, "CRC error"); } else { png_chunk_benign_error(png_ptr, "CRC error"); return (0); } return (1); } return (0); } /* Compare the CRC stored in the PNG file with that calculated by libpng from * the data it has read thus far. */ int /* PRIVATE */ png_crc_error(png_structp png_ptr) { png_byte crc_bytes[4]; png_uint_32 crc; int need_crc = 1; if (PNG_CHUNK_ANCILLIARY(png_ptr->chunk_name)) { if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) == (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN)) need_crc = 0; } else /* critical */ { if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) need_crc = 0; } #ifdef PNG_IO_STATE_SUPPORTED png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_CRC; #endif /* The chunk CRC must be serialized in a single I/O call. */ png_read_data(png_ptr, crc_bytes, 4); if (need_crc) { crc = png_get_uint_32(crc_bytes); return ((int)(crc != png_ptr->crc)); } else return (0); } #ifdef PNG_READ_COMPRESSED_TEXT_SUPPORTED static png_size_t png_inflate(png_structp png_ptr, png_bytep data, png_size_t size, png_bytep output, png_size_t output_size) { png_size_t count = 0; /* zlib can't necessarily handle more than 65535 bytes at once (i.e. it can't * even necessarily handle 65536 bytes) because the type uInt is "16 bits or * more". Consequently it is necessary to chunk the input to zlib. This * code uses ZLIB_IO_MAX, from pngpriv.h, as the maximum (the maximum value * that can be stored in a uInt.) It is possible to set ZLIB_IO_MAX to a * lower value in pngpriv.h and this may sometimes have a performance * advantage, because it forces access of the input data to be separated from * at least some of the use by some period of time. */ png_ptr->zstream.next_in = data; /* avail_in is set below from 'size' */ png_ptr->zstream.avail_in = 0; while (1) { int ret, avail; /* The setting of 'avail_in' used to be outside the loop, by setting it * inside it is possible to chunk the input to zlib and simply rely on * zlib to advance the 'next_in' pointer. This allows arbitrary amounts o * data to be passed through zlib at the unavoidable cost of requiring a * window save (memcpy of up to 32768 output bytes) every ZLIB_IO_MAX * input bytes. */ if (png_ptr->zstream.avail_in == 0 && size > 0) { if (size <= ZLIB_IO_MAX) { /* The value is less than ZLIB_IO_MAX so the cast is safe: */ png_ptr->zstream.avail_in = (uInt)size; size = 0; } else { png_ptr->zstream.avail_in = ZLIB_IO_MAX; size -= ZLIB_IO_MAX; } } /* Reset the output buffer each time round - we empty it * after every inflate call. */ png_ptr->zstream.next_out = png_ptr->zbuf; png_ptr->zstream.avail_out = png_ptr->zbuf_size; ret = inflate(&png_ptr->zstream, Z_NO_FLUSH); avail = png_ptr->zbuf_size - png_ptr->zstream.avail_out; /* First copy/count any new output - but only if we didn't * get an error code. */ if ((ret == Z_OK || ret == Z_STREAM_END) && avail > 0) { png_size_t space = avail; /* > 0, see above */ if (output != 0 && output_size > count) { png_size_t copy = output_size - count; if (space < copy) copy = space; png_memcpy(output + count, png_ptr->zbuf, copy); } count += space; } if (ret == Z_OK) continue; /* Termination conditions - always reset the zstream, it * must be left in inflateInit state. */ png_ptr->zstream.avail_in = 0; inflateReset(&png_ptr->zstream); if (ret == Z_STREAM_END) return count; /* NOTE: may be zero. */ /* Now handle the error codes - the API always returns 0 * and the error message is dumped into the uncompressed * buffer if available. */ # ifdef PNG_WARNINGS_SUPPORTED { png_const_charp msg; if (png_ptr->zstream.msg != 0) msg = png_ptr->zstream.msg; else switch (ret) { case Z_BUF_ERROR: msg = "Buffer error in compressed datastream"; break; case Z_DATA_ERROR: msg = "Data error in compressed datastream"; break; default: msg = "Incomplete compressed datastream"; break; } png_chunk_warning(png_ptr, msg); } # endif /* 0 means an error - notice that this code simply ignores * zero length compressed chunks as a result. */ return 0; } } /* * Decompress trailing data in a chunk. The assumption is that chunkdata * points at an allocated area holding the contents of a chunk with a * trailing compressed part. What we get back is an allocated area * holding the original prefix part and an uncompressed version of the * trailing part (the malloc area passed in is freed). */ void /* PRIVATE */ png_decompress_chunk(png_structp png_ptr, int comp_type, png_size_t chunklength, png_size_t prefix_size, png_size_t *newlength) { /* The caller should guarantee this */ if (prefix_size > chunklength) { /* The recovery is to delete the chunk. */ png_warning(png_ptr, "invalid chunklength"); prefix_size = 0; /* To delete everything */ } else if (comp_type == PNG_COMPRESSION_TYPE_BASE) { png_size_t expanded_size = png_inflate(png_ptr, (png_bytep)(png_ptr->chunkdata + prefix_size), chunklength - prefix_size, 0, /* output */ 0); /* output size */ /* Now check the limits on this chunk - if the limit fails the * compressed data will be removed, the prefix will remain. */ #ifdef PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED if (png_ptr->user_chunk_malloc_max && (prefix_size + expanded_size >= png_ptr->user_chunk_malloc_max - 1)) #else # ifdef PNG_USER_CHUNK_MALLOC_MAX if ((PNG_USER_CHUNK_MALLOC_MAX > 0) && prefix_size + expanded_size >= PNG_USER_CHUNK_MALLOC_MAX - 1) # endif #endif png_warning(png_ptr, "Exceeded size limit while expanding chunk"); /* If the size is zero either there was an error and a message * has already been output (warning) or the size really is zero * and we have nothing to do - the code will exit through the * error case below. */ #if defined(PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED) || \ defined(PNG_USER_CHUNK_MALLOC_MAX) else if (expanded_size > 0) #else if (expanded_size > 0) #endif { /* Success (maybe) - really uncompress the chunk. */ png_size_t new_size = 0; png_charp text = (png_charp)png_malloc_warn(png_ptr, prefix_size + expanded_size + 1); if (text != NULL) { png_memcpy(text, png_ptr->chunkdata, prefix_size); new_size = png_inflate(png_ptr, (png_bytep)(png_ptr->chunkdata + prefix_size), chunklength - prefix_size, (png_bytep)(text + prefix_size), expanded_size); text[prefix_size + expanded_size] = 0; /* just in case */ if (new_size == expanded_size) { png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = text; *newlength = prefix_size + expanded_size; return; /* The success return! */ } png_warning(png_ptr, "png_inflate logic error"); png_free(png_ptr, text); } else png_warning(png_ptr, "Not enough memory to decompress chunk"); } } else /* if (comp_type != PNG_COMPRESSION_TYPE_BASE) */ { PNG_WARNING_PARAMETERS(p) png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_d, comp_type); png_formatted_warning(png_ptr, p, "Unknown zTXt compression type @1"); /* The recovery is to simply drop the data. */ } /* Generic error return - leave the prefix, delete the compressed * data, reallocate the chunkdata to remove the potentially large * amount of compressed data. */ { png_charp text = (png_charp)png_malloc_warn(png_ptr, prefix_size + 1); if (text != NULL) { if (prefix_size > 0) png_memcpy(text, png_ptr->chunkdata, prefix_size); png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = text; /* This is an extra zero in the 'uncompressed' part. */ *(png_ptr->chunkdata + prefix_size) = 0x00; } /* Ignore a malloc error here - it is safe. */ } *newlength = prefix_size; } #endif /* PNG_READ_COMPRESSED_TEXT_SUPPORTED */ /* Read and check the IDHR chunk */ void /* PRIVATE */ png_handle_IHDR(png_structp png_ptr, png_infop info_ptr, png_uint_32 length) { png_byte buf[13]; png_uint_32 width, height; int bit_depth, color_type, compression_type, filter_type; int interlace_type; png_debug(1, "in png_handle_IHDR"); if (png_ptr->mode & PNG_HAVE_IHDR) png_error(png_ptr, "Out of place IHDR"); /* Check the length */ if (length != 13) png_error(png_ptr, "Invalid IHDR chunk"); png_ptr->mode |= PNG_HAVE_IHDR; png_crc_read(png_ptr, buf, 13); png_crc_finish(png_ptr, 0); width = png_get_uint_31(png_ptr, buf); height = png_get_uint_31(png_ptr, buf + 4); bit_depth = buf[8]; color_type = buf[9]; compression_type = buf[10]; filter_type = buf[11]; interlace_type = buf[12]; /* Set internal variables */ png_ptr->width = width; png_ptr->height = height; png_ptr->bit_depth = (png_byte)bit_depth; png_ptr->interlaced = (png_byte)interlace_type; png_ptr->color_type = (png_byte)color_type; #ifdef PNG_MNG_FEATURES_SUPPORTED png_ptr->filter_type = (png_byte)filter_type; #endif png_ptr->compression_type = (png_byte)compression_type; /* Find number of channels */ switch (png_ptr->color_type) { default: /* invalid, png_set_IHDR calls png_error */ case PNG_COLOR_TYPE_GRAY: case PNG_COLOR_TYPE_PALETTE: png_ptr->channels = 1; break; case PNG_COLOR_TYPE_RGB: png_ptr->channels = 3; break; case PNG_COLOR_TYPE_GRAY_ALPHA: png_ptr->channels = 2; break; case PNG_COLOR_TYPE_RGB_ALPHA: png_ptr->channels = 4; break; } /* Set up other useful info */ png_ptr->pixel_depth = (png_byte)(png_ptr->bit_depth * png_ptr->channels); png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->width); png_debug1(3, "bit_depth = %d", png_ptr->bit_depth); png_debug1(3, "channels = %d", png_ptr->channels); png_debug1(3, "rowbytes = %lu", (unsigned long)png_ptr->rowbytes); png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth, color_type, interlace_type, compression_type, filter_type); } /* Read and check the palette */ void /* PRIVATE */ png_handle_PLTE(png_structp png_ptr, png_infop info_ptr, png_uint_32 length) { png_color palette[PNG_MAX_PALETTE_LENGTH]; int num, i; #ifdef PNG_POINTER_INDEXING_SUPPORTED png_colorp pal_ptr; #endif png_debug(1, "in png_handle_PLTE"); if (!(png_ptr->mode & PNG_HAVE_IHDR)) png_error(png_ptr, "Missing IHDR before PLTE"); else if (png_ptr->mode & PNG_HAVE_IDAT) { png_warning(png_ptr, "Invalid PLTE after IDAT"); png_crc_finish(png_ptr, length); return; } else if (png_ptr->mode & PNG_HAVE_PLTE) png_error(png_ptr, "Duplicate PLTE chunk"); png_ptr->mode |= PNG_HAVE_PLTE; if (!(png_ptr->color_type&PNG_COLOR_MASK_COLOR)) { png_warning(png_ptr, "Ignoring PLTE chunk in grayscale PNG"); png_crc_finish(png_ptr, length); return; } #ifndef PNG_READ_OPT_PLTE_SUPPORTED if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE) { png_crc_finish(png_ptr, length); return; } #endif if (length > 3*PNG_MAX_PALETTE_LENGTH || length % 3) { if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE) { png_warning(png_ptr, "Invalid palette chunk"); png_crc_finish(png_ptr, length); return; } else { png_error(png_ptr, "Invalid palette chunk"); } } num = (int)length / 3; #ifdef PNG_POINTER_INDEXING_SUPPORTED for (i = 0, pal_ptr = palette; i < num; i++, pal_ptr++) { png_byte buf[3]; png_crc_read(png_ptr, buf, 3); pal_ptr->red = buf[0]; pal_ptr->green = buf[1]; pal_ptr->blue = buf[2]; } #else for (i = 0; i < num; i++) { png_byte buf[3]; png_crc_read(png_ptr, buf, 3); /* Don't depend upon png_color being any order */ palette[i].red = buf[0]; palette[i].green = buf[1]; palette[i].blue = buf[2]; } #endif /* If we actually need the PLTE chunk (ie for a paletted image), we do * whatever the normal CRC configuration tells us. However, if we * have an RGB image, the PLTE can be considered ancillary, so * we will act as though it is. */ #ifndef PNG_READ_OPT_PLTE_SUPPORTED if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) #endif { png_crc_finish(png_ptr, 0); } #ifndef PNG_READ_OPT_PLTE_SUPPORTED else if (png_crc_error(png_ptr)) /* Only if we have a CRC error */ { /* If we don't want to use the data from an ancillary chunk, * we have two options: an error abort, or a warning and we * ignore the data in this chunk (which should be OK, since * it's considered ancillary for a RGB or RGBA image). */ if (!(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_USE)) { if (png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) { png_chunk_benign_error(png_ptr, "CRC error"); } else { png_chunk_warning(png_ptr, "CRC error"); return; } } /* Otherwise, we (optionally) emit a warning and use the chunk. */ else if (!(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN)) { png_chunk_warning(png_ptr, "CRC error"); } } #endif png_set_PLTE(png_ptr, info_ptr, palette, num); #ifdef PNG_READ_tRNS_SUPPORTED if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) { if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS)) { if (png_ptr->num_trans > (png_uint_16)num) { png_warning(png_ptr, "Truncating incorrect tRNS chunk length"); png_ptr->num_trans = (png_uint_16)num; } if (info_ptr->num_trans > (png_uint_16)num) { png_warning(png_ptr, "Truncating incorrect info tRNS chunk length"); info_ptr->num_trans = (png_uint_16)num; } } } #endif } void /* PRIVATE */ png_handle_IEND(png_structp png_ptr, png_infop info_ptr, png_uint_32 length) { png_debug(1, "in png_handle_IEND"); if (!(png_ptr->mode & PNG_HAVE_IHDR) || !(png_ptr->mode & PNG_HAVE_IDAT)) { png_error(png_ptr, "No image in file"); } png_ptr->mode |= (PNG_AFTER_IDAT | PNG_HAVE_IEND); if (length != 0) { png_warning(png_ptr, "Incorrect IEND chunk length"); } png_crc_finish(png_ptr, length); PNG_UNUSED(info_ptr) /* Quiet compiler warnings about unused info_ptr */ } #ifdef PNG_READ_gAMA_SUPPORTED void /* PRIVATE */ png_handle_gAMA(png_structp png_ptr, png_infop info_ptr, png_uint_32 length) { png_fixed_point igamma; png_byte buf[4]; png_debug(1, "in png_handle_gAMA"); if (!(png_ptr->mode & PNG_HAVE_IHDR)) png_error(png_ptr, "Missing IHDR before gAMA"); else if (png_ptr->mode & PNG_HAVE_IDAT) { png_warning(png_ptr, "Invalid gAMA after IDAT"); png_crc_finish(png_ptr, length); return; } else if (png_ptr->mode & PNG_HAVE_PLTE) /* Should be an error, but we can cope with it */ png_warning(png_ptr, "Out of place gAMA chunk"); if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_gAMA) #ifdef PNG_READ_sRGB_SUPPORTED && !(info_ptr->valid & PNG_INFO_sRGB) #endif ) { png_warning(png_ptr, "Duplicate gAMA chunk"); png_crc_finish(png_ptr, length); return; } if (length != 4) { png_warning(png_ptr, "Incorrect gAMA chunk length"); png_crc_finish(png_ptr, length); return; } png_crc_read(png_ptr, buf, 4); if (png_crc_finish(png_ptr, 0)) return; igamma = png_get_fixed_point(NULL, buf); /* Check for zero gamma or an error. */ if (igamma <= 0) { png_warning(png_ptr, "Ignoring gAMA chunk with out of range gamma"); return; } # ifdef PNG_READ_sRGB_SUPPORTED if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sRGB)) { if (PNG_OUT_OF_RANGE(igamma, 45500, 500)) { PNG_WARNING_PARAMETERS(p) png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_fixed, igamma); png_formatted_warning(png_ptr, p, "Ignoring incorrect gAMA value @1 when sRGB is also present"); return; } } # endif /* PNG_READ_sRGB_SUPPORTED */ # ifdef PNG_READ_GAMMA_SUPPORTED /* Gamma correction on read is supported. */ png_ptr->gamma = igamma; # endif /* And set the 'info' structure members. */ png_set_gAMA_fixed(png_ptr, info_ptr, igamma); } #endif #ifdef PNG_READ_sBIT_SUPPORTED void /* PRIVATE */ png_handle_sBIT(png_structp png_ptr, png_infop info_ptr, png_uint_32 length) { png_size_t truelen; png_byte buf[4]; png_debug(1, "in png_handle_sBIT"); buf[0] = buf[1] = buf[2] = buf[3] = 0; if (!(png_ptr->mode & PNG_HAVE_IHDR)) png_error(png_ptr, "Missing IHDR before sBIT"); else if (png_ptr->mode & PNG_HAVE_IDAT) { png_warning(png_ptr, "Invalid sBIT after IDAT"); png_crc_finish(png_ptr, length); return; } else if (png_ptr->mode & PNG_HAVE_PLTE) { /* Should be an error, but we can cope with it */ png_warning(png_ptr, "Out of place sBIT chunk"); } if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT)) { png_warning(png_ptr, "Duplicate sBIT chunk"); png_crc_finish(png_ptr, length); return; } if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) truelen = 3; else truelen = (png_size_t)png_ptr->channels; if (length != truelen || length > 4) { png_warning(png_ptr, "Incorrect sBIT chunk length"); png_crc_finish(png_ptr, length); return; } png_crc_read(png_ptr, buf, truelen); if (png_crc_finish(png_ptr, 0)) return; if (png_ptr->color_type & PNG_COLOR_MASK_COLOR) { png_ptr->sig_bit.red = buf[0]; png_ptr->sig_bit.green = buf[1]; png_ptr->sig_bit.blue = buf[2]; png_ptr->sig_bit.alpha = buf[3]; } else { png_ptr->sig_bit.gray = buf[0]; png_ptr->sig_bit.red = buf[0]; png_ptr->sig_bit.green = buf[0]; png_ptr->sig_bit.blue = buf[0]; png_ptr->sig_bit.alpha = buf[1]; } png_set_sBIT(png_ptr, info_ptr, &(png_ptr->sig_bit)); } #endif #ifdef PNG_READ_cHRM_SUPPORTED void /* PRIVATE */ png_handle_cHRM(png_structp png_ptr, png_infop info_ptr, png_uint_32 length) { png_byte buf[32]; png_fixed_point x_white, y_white, x_red, y_red, x_green, y_green, x_blue, y_blue; png_debug(1, "in png_handle_cHRM"); if (!(png_ptr->mode & PNG_HAVE_IHDR)) png_error(png_ptr, "Missing IHDR before cHRM"); else if (png_ptr->mode & PNG_HAVE_IDAT) { png_warning(png_ptr, "Invalid cHRM after IDAT"); png_crc_finish(png_ptr, length); return; } else if (png_ptr->mode & PNG_HAVE_PLTE) /* Should be an error, but we can cope with it */ png_warning(png_ptr, "Missing PLTE before cHRM"); if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_cHRM) # ifdef PNG_READ_sRGB_SUPPORTED && !(info_ptr->valid & PNG_INFO_sRGB) # endif ) { png_warning(png_ptr, "Duplicate cHRM chunk"); png_crc_finish(png_ptr, length); return; } if (length != 32) { png_warning(png_ptr, "Incorrect cHRM chunk length"); png_crc_finish(png_ptr, length); return; } png_crc_read(png_ptr, buf, 32); if (png_crc_finish(png_ptr, 0)) return; x_white = png_get_fixed_point(NULL, buf); y_white = png_get_fixed_point(NULL, buf + 4); x_red = png_get_fixed_point(NULL, buf + 8); y_red = png_get_fixed_point(NULL, buf + 12); x_green = png_get_fixed_point(NULL, buf + 16); y_green = png_get_fixed_point(NULL, buf + 20); x_blue = png_get_fixed_point(NULL, buf + 24); y_blue = png_get_fixed_point(NULL, buf + 28); if (x_white == PNG_FIXED_ERROR || y_white == PNG_FIXED_ERROR || x_red == PNG_FIXED_ERROR || y_red == PNG_FIXED_ERROR || x_green == PNG_FIXED_ERROR || y_green == PNG_FIXED_ERROR || x_blue == PNG_FIXED_ERROR || y_blue == PNG_FIXED_ERROR) { png_warning(png_ptr, "Ignoring cHRM chunk with negative chromaticities"); return; } #ifdef PNG_READ_sRGB_SUPPORTED if ((info_ptr != NULL) && (info_ptr->valid & PNG_INFO_sRGB)) { if (PNG_OUT_OF_RANGE(x_white, 31270, 1000) || PNG_OUT_OF_RANGE(y_white, 32900, 1000) || PNG_OUT_OF_RANGE(x_red, 64000, 1000) || PNG_OUT_OF_RANGE(y_red, 33000, 1000) || PNG_OUT_OF_RANGE(x_green, 30000, 1000) || PNG_OUT_OF_RANGE(y_green, 60000, 1000) || PNG_OUT_OF_RANGE(x_blue, 15000, 1000) || PNG_OUT_OF_RANGE(y_blue, 6000, 1000)) { PNG_WARNING_PARAMETERS(p) png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_fixed, x_white); png_warning_parameter_signed(p, 2, PNG_NUMBER_FORMAT_fixed, y_white); png_warning_parameter_signed(p, 3, PNG_NUMBER_FORMAT_fixed, x_red); png_warning_parameter_signed(p, 4, PNG_NUMBER_FORMAT_fixed, y_red); png_warning_parameter_signed(p, 5, PNG_NUMBER_FORMAT_fixed, x_green); png_warning_parameter_signed(p, 6, PNG_NUMBER_FORMAT_fixed, y_green); png_warning_parameter_signed(p, 7, PNG_NUMBER_FORMAT_fixed, x_blue); png_warning_parameter_signed(p, 8, PNG_NUMBER_FORMAT_fixed, y_blue); png_formatted_warning(png_ptr, p, "Ignoring incorrect cHRM white(@1,@2) r(@3,@4)g(@5,@6)b(@7,@8) " "when sRGB is also present"); } return; } #endif /* PNG_READ_sRGB_SUPPORTED */ #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED /* Store the _white values as default coefficients for the rgb to gray * operation if it is supported. Check if the transform is already set to * avoid destroying the transform values. */ if (!png_ptr->rgb_to_gray_coefficients_set) { /* png_set_background has not been called and we haven't seen an sRGB * chunk yet. Find the XYZ of the three end points. */ png_XYZ XYZ; png_xy xy; xy.redx = x_red; xy.redy = y_red; xy.greenx = x_green; xy.greeny = y_green; xy.bluex = x_blue; xy.bluey = y_blue; xy.whitex = x_white; xy.whitey = y_white; if (png_XYZ_from_xy_checked(png_ptr, &XYZ, xy)) { /* The success case, because XYZ_from_xy normalises to a reference * white Y of 1.0 we just need to scale the numbers. This should * always work just fine. It is an internal error if this overflows. */ { png_fixed_point r, g, b; if (png_muldiv(&r, XYZ.redY, 32768, PNG_FP_1) && r >= 0 && r <= 32768 && png_muldiv(&g, XYZ.greenY, 32768, PNG_FP_1) && g >= 0 && g <= 32768 && png_muldiv(&b, XYZ.blueY, 32768, PNG_FP_1) && b >= 0 && b <= 32768 && r+g+b <= 32769) { /* We allow 0 coefficients here. r+g+b may be 32769 if two or * all of the coefficients were rounded up. Handle this by * reducing the *largest* coefficient by 1; this matches the * approach used for the default coefficients in pngrtran.c */ int add = 0; if (r+g+b > 32768) add = -1; else if (r+g+b < 32768) add = 1; if (add != 0) { if (g >= r && g >= b) g += add; else if (r >= g && r >= b) r += add; else b += add; } /* Check for an internal error. */ if (r+g+b != 32768) png_error(png_ptr, "internal error handling cHRM coefficients"); png_ptr->rgb_to_gray_red_coeff = (png_uint_16)r; png_ptr->rgb_to_gray_green_coeff = (png_uint_16)g; } /* This is a png_error at present even though it could be ignored - * it should never happen, but it is important that if it does, the * bug is fixed. */ else png_error(png_ptr, "internal error handling cHRM->XYZ"); } } } #endif png_set_cHRM_fixed(png_ptr, info_ptr, x_white, y_white, x_red, y_red, x_green, y_green, x_blue, y_blue); } #endif #ifdef PNG_READ_sRGB_SUPPORTED void /* PRIVATE */ png_handle_sRGB(png_structp png_ptr, png_infop info_ptr, png_uint_32 length) { int intent; png_byte buf[1]; png_debug(1, "in png_handle_sRGB"); if (!(png_ptr->mode & PNG_HAVE_IHDR)) png_error(png_ptr, "Missing IHDR before sRGB"); else if (png_ptr->mode & PNG_HAVE_IDAT) { png_warning(png_ptr, "Invalid sRGB after IDAT"); png_crc_finish(png_ptr, length); return; } else if (png_ptr->mode & PNG_HAVE_PLTE) /* Should be an error, but we can cope with it */ png_warning(png_ptr, "Out of place sRGB chunk"); if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sRGB)) { png_warning(png_ptr, "Duplicate sRGB chunk"); png_crc_finish(png_ptr, length); return; } if (length != 1) { png_warning(png_ptr, "Incorrect sRGB chunk length"); png_crc_finish(png_ptr, length); return; } png_crc_read(png_ptr, buf, 1); if (png_crc_finish(png_ptr, 0)) return; intent = buf[0]; /* Check for bad intent */ if (intent >= PNG_sRGB_INTENT_LAST) { png_warning(png_ptr, "Unknown sRGB intent"); return; } #if defined(PNG_READ_gAMA_SUPPORTED) && defined(PNG_READ_GAMMA_SUPPORTED) if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_gAMA)) { if (PNG_OUT_OF_RANGE(info_ptr->gamma, 45500, 500)) { PNG_WARNING_PARAMETERS(p) png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_fixed, info_ptr->gamma); png_formatted_warning(png_ptr, p, "Ignoring incorrect gAMA value @1 when sRGB is also present"); } } #endif /* PNG_READ_gAMA_SUPPORTED */ #ifdef PNG_READ_cHRM_SUPPORTED if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_cHRM)) if (PNG_OUT_OF_RANGE(info_ptr->x_white, 31270, 1000) || PNG_OUT_OF_RANGE(info_ptr->y_white, 32900, 1000) || PNG_OUT_OF_RANGE(info_ptr->x_red, 64000, 1000) || PNG_OUT_OF_RANGE(info_ptr->y_red, 33000, 1000) || PNG_OUT_OF_RANGE(info_ptr->x_green, 30000, 1000) || PNG_OUT_OF_RANGE(info_ptr->y_green, 60000, 1000) || PNG_OUT_OF_RANGE(info_ptr->x_blue, 15000, 1000) || PNG_OUT_OF_RANGE(info_ptr->y_blue, 6000, 1000)) { png_warning(png_ptr, "Ignoring incorrect cHRM value when sRGB is also present"); } #endif /* PNG_READ_cHRM_SUPPORTED */ /* This is recorded for use when handling the cHRM chunk above. An sRGB * chunk unconditionally overwrites the coefficients for grayscale conversion * too. */ png_ptr->is_sRGB = 1; # ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED /* Don't overwrite user supplied values: */ if (!png_ptr->rgb_to_gray_coefficients_set) { /* These numbers come from the sRGB specification (or, since one has to * pay much money to get a copy, the wikipedia sRGB page) the * chromaticity values quoted have been inverted to get the reverse * transformation from RGB to XYZ and the 'Y' coefficients scaled by * 32768 (then rounded). * * sRGB and ITU Rec-709 both truncate the values for the D65 white * point to four digits and, even though it actually stores five * digits, the PNG spec gives the truncated value. * * This means that when the chromaticities are converted back to XYZ * end points we end up with (6968,23435,2366), which, as described in * pngrtran.c, would overflow. If the five digit precision and up is * used we get, instead: * * 6968*R + 23435*G + 2365*B * * (Notice that this rounds the blue coefficient down, rather than the * choice used in pngrtran.c which is to round the green one down.) */ png_ptr->rgb_to_gray_red_coeff = 6968; /* 0.212639005871510 */ png_ptr->rgb_to_gray_green_coeff = 23434; /* 0.715168678767756 */ /* png_ptr->rgb_to_gray_blue_coeff = 2366; 0.072192315360734 */ /* The following keeps the cHRM chunk from destroying the * coefficients again in the event that it follows the sRGB chunk. */ png_ptr->rgb_to_gray_coefficients_set = 1; } # endif png_set_sRGB_gAMA_and_cHRM(png_ptr, info_ptr, intent); } #endif /* PNG_READ_sRGB_SUPPORTED */ #ifdef PNG_READ_iCCP_SUPPORTED void /* PRIVATE */ png_handle_iCCP(png_structp png_ptr, png_infop info_ptr, png_uint_32 length) /* Note: this does not properly handle chunks that are > 64K under DOS */ { png_byte compression_type; png_bytep pC; png_charp profile; png_uint_32 skip = 0; png_uint_32 profile_size; png_alloc_size_t profile_length; png_size_t slength, prefix_length, data_length; png_debug(1, "in png_handle_iCCP"); if (!(png_ptr->mode & PNG_HAVE_IHDR)) png_error(png_ptr, "Missing IHDR before iCCP"); else if (png_ptr->mode & PNG_HAVE_IDAT) { png_warning(png_ptr, "Invalid iCCP after IDAT"); png_crc_finish(png_ptr, length); return; } else if (png_ptr->mode & PNG_HAVE_PLTE) /* Should be an error, but we can cope with it */ png_warning(png_ptr, "Out of place iCCP chunk"); if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_iCCP)) { png_warning(png_ptr, "Duplicate iCCP chunk"); png_crc_finish(png_ptr, length); return; } #ifdef PNG_MAX_MALLOC_64K if (length > (png_uint_32)65535L) { png_warning(png_ptr, "iCCP chunk too large to fit in memory"); skip = length - (png_uint_32)65535L; length = (png_uint_32)65535L; } #endif png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = (png_charp)png_malloc(png_ptr, length + 1); slength = (png_size_t)length; png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength); if (png_crc_finish(png_ptr, skip)) { png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; return; } png_ptr->chunkdata[slength] = 0x00; for (profile = png_ptr->chunkdata; *profile; profile++) /* Empty loop to find end of name */ ; ++profile; /* There should be at least one zero (the compression type byte) * following the separator, and we should be on it */ if (profile >= png_ptr->chunkdata + slength - 1) { png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; png_warning(png_ptr, "Malformed iCCP chunk"); return; } /* Compression_type should always be zero */ compression_type = *profile++; if (compression_type) { png_warning(png_ptr, "Ignoring nonzero compression type in iCCP chunk"); compression_type = 0x00; /* Reset it to zero (libpng-1.0.6 through 1.0.8 wrote nonzero) */ } prefix_length = profile - png_ptr->chunkdata; png_decompress_chunk(png_ptr, compression_type, slength, prefix_length, &data_length); profile_length = data_length - prefix_length; if (prefix_length > data_length || profile_length < 4) { png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; png_warning(png_ptr, "Profile size field missing from iCCP chunk"); return; } /* Check the profile_size recorded in the first 32 bits of the ICC profile */ pC = (png_bytep)(png_ptr->chunkdata + prefix_length); profile_size = ((*(pC )) << 24) | ((*(pC + 1)) << 16) | ((*(pC + 2)) << 8) | ((*(pC + 3)) ); /* NOTE: the following guarantees that 'profile_length' fits into 32 bits, * because profile_size is a 32 bit value. */ if (profile_size < profile_length) profile_length = profile_size; /* And the following guarantees that profile_size == profile_length. */ if (profile_size > profile_length) { PNG_WARNING_PARAMETERS(p) png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; png_warning_parameter_unsigned(p, 1, PNG_NUMBER_FORMAT_u, profile_size); png_warning_parameter_unsigned(p, 2, PNG_NUMBER_FORMAT_u, profile_length); png_formatted_warning(png_ptr, p, "Ignoring iCCP chunk with declared size = @1 and actual length = @2"); return; } png_set_iCCP(png_ptr, info_ptr, png_ptr->chunkdata, compression_type, (png_bytep)png_ptr->chunkdata + prefix_length, profile_size); png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; } #endif /* PNG_READ_iCCP_SUPPORTED */ #ifdef PNG_READ_sPLT_SUPPORTED void /* PRIVATE */ png_handle_sPLT(png_structp png_ptr, png_infop info_ptr, png_uint_32 length) /* Note: this does not properly handle chunks that are > 64K under DOS */ { png_bytep entry_start; png_sPLT_t new_palette; png_sPLT_entryp pp; png_uint_32 data_length; int entry_size, i; png_uint_32 skip = 0; png_size_t slength; png_uint_32 dl; png_size_t max_dl; png_debug(1, "in png_handle_sPLT"); #ifdef PNG_USER_LIMITS_SUPPORTED if (png_ptr->user_chunk_cache_max != 0) { if (png_ptr->user_chunk_cache_max == 1) { png_crc_finish(png_ptr, length); return; } if (--png_ptr->user_chunk_cache_max == 1) { png_warning(png_ptr, "No space in chunk cache for sPLT"); png_crc_finish(png_ptr, length); return; } } #endif if (!(png_ptr->mode & PNG_HAVE_IHDR)) png_error(png_ptr, "Missing IHDR before sPLT"); else if (png_ptr->mode & PNG_HAVE_IDAT) { png_warning(png_ptr, "Invalid sPLT after IDAT"); png_crc_finish(png_ptr, length); return; } #ifdef PNG_MAX_MALLOC_64K if (length > (png_uint_32)65535L) { png_warning(png_ptr, "sPLT chunk too large to fit in memory"); skip = length - (png_uint_32)65535L; length = (png_uint_32)65535L; } #endif png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = (png_charp)png_malloc(png_ptr, length + 1); /* WARNING: this may break if size_t is less than 32 bits; it is assumed * that the PNG_MAX_MALLOC_64K test is enabled in this case, but this is a * potential breakage point if the types in pngconf.h aren't exactly right. */ slength = (png_size_t)length; png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength); if (png_crc_finish(png_ptr, skip)) { png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; return; } png_ptr->chunkdata[slength] = 0x00; for (entry_start = (png_bytep)png_ptr->chunkdata; *entry_start; entry_start++) /* Empty loop to find end of name */ ; ++entry_start; /* A sample depth should follow the separator, and we should be on it */ if (entry_start > (png_bytep)png_ptr->chunkdata + slength - 2) { png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; png_warning(png_ptr, "malformed sPLT chunk"); return; } new_palette.depth = *entry_start++; entry_size = (new_palette.depth == 8 ? 6 : 10); /* This must fit in a png_uint_32 because it is derived from the original * chunk data length (and use 'length', not 'slength' here for clarity - * they are guaranteed to be the same, see the tests above.) */ data_length = length - (png_uint_32)(entry_start - (png_bytep)png_ptr->chunkdata); /* Integrity-check the data length */ if (data_length % entry_size) { png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; png_warning(png_ptr, "sPLT chunk has bad length"); return; } dl = (png_int_32)(data_length / entry_size); max_dl = PNG_SIZE_MAX / png_sizeof(png_sPLT_entry); if (dl > max_dl) { png_warning(png_ptr, "sPLT chunk too long"); return; } new_palette.nentries = (png_int_32)(data_length / entry_size); new_palette.entries = (png_sPLT_entryp)png_malloc_warn( png_ptr, new_palette.nentries * png_sizeof(png_sPLT_entry)); if (new_palette.entries == NULL) { png_warning(png_ptr, "sPLT chunk requires too much memory"); return; } #ifdef PNG_POINTER_INDEXING_SUPPORTED for (i = 0; i < new_palette.nentries; i++) { pp = new_palette.entries + i; if (new_palette.depth == 8) { pp->red = *entry_start++; pp->green = *entry_start++; pp->blue = *entry_start++; pp->alpha = *entry_start++; } else { pp->red = png_get_uint_16(entry_start); entry_start += 2; pp->green = png_get_uint_16(entry_start); entry_start += 2; pp->blue = png_get_uint_16(entry_start); entry_start += 2; pp->alpha = png_get_uint_16(entry_start); entry_start += 2; } pp->frequency = png_get_uint_16(entry_start); entry_start += 2; } #else pp = new_palette.entries; for (i = 0; i < new_palette.nentries; i++) { if (new_palette.depth == 8) { pp[i].red = *entry_start++; pp[i].green = *entry_start++; pp[i].blue = *entry_start++; pp[i].alpha = *entry_start++; } else { pp[i].red = png_get_uint_16(entry_start); entry_start += 2; pp[i].green = png_get_uint_16(entry_start); entry_start += 2; pp[i].blue = png_get_uint_16(entry_start); entry_start += 2; pp[i].alpha = png_get_uint_16(entry_start); entry_start += 2; } pp[i].frequency = png_get_uint_16(entry_start); entry_start += 2; } #endif /* Discard all chunk data except the name and stash that */ new_palette.name = png_ptr->chunkdata; png_set_sPLT(png_ptr, info_ptr, &new_palette, 1); png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; png_free(png_ptr, new_palette.entries); } #endif /* PNG_READ_sPLT_SUPPORTED */ #ifdef PNG_READ_tRNS_SUPPORTED void /* PRIVATE */ png_handle_tRNS(png_structp png_ptr, png_infop info_ptr, png_uint_32 length) { png_byte readbuf[PNG_MAX_PALETTE_LENGTH]; png_debug(1, "in png_handle_tRNS"); if (!(png_ptr->mode & PNG_HAVE_IHDR)) png_error(png_ptr, "Missing IHDR before tRNS"); else if (png_ptr->mode & PNG_HAVE_IDAT) { png_warning(png_ptr, "Invalid tRNS after IDAT"); png_crc_finish(png_ptr, length); return; } else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS)) { png_warning(png_ptr, "Duplicate tRNS chunk"); png_crc_finish(png_ptr, length); return; } if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY) { png_byte buf[2]; if (length != 2) { png_warning(png_ptr, "Incorrect tRNS chunk length"); png_crc_finish(png_ptr, length); return; } png_crc_read(png_ptr, buf, 2); png_ptr->num_trans = 1; png_ptr->trans_color.gray = png_get_uint_16(buf); } else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB) { png_byte buf[6]; if (length != 6) { png_warning(png_ptr, "Incorrect tRNS chunk length"); png_crc_finish(png_ptr, length); return; } png_crc_read(png_ptr, buf, (png_size_t)length); png_ptr->num_trans = 1; png_ptr->trans_color.red = png_get_uint_16(buf); png_ptr->trans_color.green = png_get_uint_16(buf + 2); png_ptr->trans_color.blue = png_get_uint_16(buf + 4); } else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) { if (!(png_ptr->mode & PNG_HAVE_PLTE)) { /* Should be an error, but we can cope with it. */ png_warning(png_ptr, "Missing PLTE before tRNS"); } if (length > (png_uint_32)png_ptr->num_palette || length > PNG_MAX_PALETTE_LENGTH) { png_warning(png_ptr, "Incorrect tRNS chunk length"); png_crc_finish(png_ptr, length); return; } if (length == 0) { png_warning(png_ptr, "Zero length tRNS chunk"); png_crc_finish(png_ptr, length); return; } png_crc_read(png_ptr, readbuf, (png_size_t)length); png_ptr->num_trans = (png_uint_16)length; } else { png_warning(png_ptr, "tRNS chunk not allowed with alpha channel"); png_crc_finish(png_ptr, length); return; } if (png_crc_finish(png_ptr, 0)) { png_ptr->num_trans = 0; return; } png_set_tRNS(png_ptr, info_ptr, readbuf, png_ptr->num_trans, &(png_ptr->trans_color)); } #endif #ifdef PNG_READ_bKGD_SUPPORTED void /* PRIVATE */ png_handle_bKGD(png_structp png_ptr, png_infop info_ptr, png_uint_32 length) { png_size_t truelen; png_byte buf[6]; png_color_16 background; png_debug(1, "in png_handle_bKGD"); if (!(png_ptr->mode & PNG_HAVE_IHDR)) png_error(png_ptr, "Missing IHDR before bKGD"); else if (png_ptr->mode & PNG_HAVE_IDAT) { png_warning(png_ptr, "Invalid bKGD after IDAT"); png_crc_finish(png_ptr, length); return; } else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE && !(png_ptr->mode & PNG_HAVE_PLTE)) { png_warning(png_ptr, "Missing PLTE before bKGD"); png_crc_finish(png_ptr, length); return; } else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD)) { png_warning(png_ptr, "Duplicate bKGD chunk"); png_crc_finish(png_ptr, length); return; } if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) truelen = 1; else if (png_ptr->color_type & PNG_COLOR_MASK_COLOR) truelen = 6; else truelen = 2; if (length != truelen) { png_warning(png_ptr, "Incorrect bKGD chunk length"); png_crc_finish(png_ptr, length); return; } png_crc_read(png_ptr, buf, truelen); if (png_crc_finish(png_ptr, 0)) return; /* We convert the index value into RGB components so that we can allow * arbitrary RGB values for background when we have transparency, and * so it is easy to determine the RGB values of the background color * from the info_ptr struct. */ if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) { background.index = buf[0]; if (info_ptr && info_ptr->num_palette) { if (buf[0] >= info_ptr->num_palette) { png_warning(png_ptr, "Incorrect bKGD chunk index value"); return; } background.red = (png_uint_16)png_ptr->palette[buf[0]].red; background.green = (png_uint_16)png_ptr->palette[buf[0]].green; background.blue = (png_uint_16)png_ptr->palette[buf[0]].blue; } else background.red = background.green = background.blue = 0; background.gray = 0; } else if (!(png_ptr->color_type & PNG_COLOR_MASK_COLOR)) /* GRAY */ { background.index = 0; background.red = background.green = background.blue = background.gray = png_get_uint_16(buf); } else { background.index = 0; background.red = png_get_uint_16(buf); background.green = png_get_uint_16(buf + 2); background.blue = png_get_uint_16(buf + 4); background.gray = 0; } png_set_bKGD(png_ptr, info_ptr, &background); } #endif #ifdef PNG_READ_hIST_SUPPORTED void /* PRIVATE */ png_handle_hIST(png_structp png_ptr, png_infop info_ptr, png_uint_32 length) { unsigned int num, i; png_uint_16 readbuf[PNG_MAX_PALETTE_LENGTH]; png_debug(1, "in png_handle_hIST"); if (!(png_ptr->mode & PNG_HAVE_IHDR)) png_error(png_ptr, "Missing IHDR before hIST"); else if (png_ptr->mode & PNG_HAVE_IDAT) { png_warning(png_ptr, "Invalid hIST after IDAT"); png_crc_finish(png_ptr, length); return; } else if (!(png_ptr->mode & PNG_HAVE_PLTE)) { png_warning(png_ptr, "Missing PLTE before hIST"); png_crc_finish(png_ptr, length); return; } else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST)) { png_warning(png_ptr, "Duplicate hIST chunk"); png_crc_finish(png_ptr, length); return; } num = length / 2 ; if (num != (unsigned int)png_ptr->num_palette || num > (unsigned int)PNG_MAX_PALETTE_LENGTH) { png_warning(png_ptr, "Incorrect hIST chunk length"); png_crc_finish(png_ptr, length); return; } for (i = 0; i < num; i++) { png_byte buf[2]; png_crc_read(png_ptr, buf, 2); readbuf[i] = png_get_uint_16(buf); } if (png_crc_finish(png_ptr, 0)) return; png_set_hIST(png_ptr, info_ptr, readbuf); } #endif #ifdef PNG_READ_pHYs_SUPPORTED void /* PRIVATE */ png_handle_pHYs(png_structp png_ptr, png_infop info_ptr, png_uint_32 length) { png_byte buf[9]; png_uint_32 res_x, res_y; int unit_type; png_debug(1, "in png_handle_pHYs"); if (!(png_ptr->mode & PNG_HAVE_IHDR)) png_error(png_ptr, "Missing IHDR before pHYs"); else if (png_ptr->mode & PNG_HAVE_IDAT) { png_warning(png_ptr, "Invalid pHYs after IDAT"); png_crc_finish(png_ptr, length); return; } else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs)) { png_warning(png_ptr, "Duplicate pHYs chunk"); png_crc_finish(png_ptr, length); return; } if (length != 9) { png_warning(png_ptr, "Incorrect pHYs chunk length"); png_crc_finish(png_ptr, length); return; } png_crc_read(png_ptr, buf, 9); if (png_crc_finish(png_ptr, 0)) return; res_x = png_get_uint_32(buf); res_y = png_get_uint_32(buf + 4); unit_type = buf[8]; png_set_pHYs(png_ptr, info_ptr, res_x, res_y, unit_type); } #endif #ifdef PNG_READ_oFFs_SUPPORTED void /* PRIVATE */ png_handle_oFFs(png_structp png_ptr, png_infop info_ptr, png_uint_32 length) { png_byte buf[9]; png_int_32 offset_x, offset_y; int unit_type; png_debug(1, "in png_handle_oFFs"); if (!(png_ptr->mode & PNG_HAVE_IHDR)) png_error(png_ptr, "Missing IHDR before oFFs"); else if (png_ptr->mode & PNG_HAVE_IDAT) { png_warning(png_ptr, "Invalid oFFs after IDAT"); png_crc_finish(png_ptr, length); return; } else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs)) { png_warning(png_ptr, "Duplicate oFFs chunk"); png_crc_finish(png_ptr, length); return; } if (length != 9) { png_warning(png_ptr, "Incorrect oFFs chunk length"); png_crc_finish(png_ptr, length); return; } png_crc_read(png_ptr, buf, 9); if (png_crc_finish(png_ptr, 0)) return; offset_x = png_get_int_32(buf); offset_y = png_get_int_32(buf + 4); unit_type = buf[8]; png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y, unit_type); } #endif #ifdef PNG_READ_pCAL_SUPPORTED /* Read the pCAL chunk (described in the PNG Extensions document) */ void /* PRIVATE */ png_handle_pCAL(png_structp png_ptr, png_infop info_ptr, png_uint_32 length) { png_int_32 X0, X1; png_byte type, nparams; png_charp buf, units, endptr; png_charpp params; png_size_t slength; int i; png_debug(1, "in png_handle_pCAL"); if (!(png_ptr->mode & PNG_HAVE_IHDR)) png_error(png_ptr, "Missing IHDR before pCAL"); else if (png_ptr->mode & PNG_HAVE_IDAT) { png_warning(png_ptr, "Invalid pCAL after IDAT"); png_crc_finish(png_ptr, length); return; } else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL)) { png_warning(png_ptr, "Duplicate pCAL chunk"); png_crc_finish(png_ptr, length); return; } png_debug1(2, "Allocating and reading pCAL chunk data (%u bytes)", length + 1); png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = (png_charp)png_malloc_warn(png_ptr, length + 1); if (png_ptr->chunkdata == NULL) { png_warning(png_ptr, "No memory for pCAL purpose"); return; } slength = (png_size_t)length; png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength); if (png_crc_finish(png_ptr, 0)) { png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; return; } png_ptr->chunkdata[slength] = 0x00; /* Null terminate the last string */ png_debug(3, "Finding end of pCAL purpose string"); for (buf = png_ptr->chunkdata; *buf; buf++) /* Empty loop */ ; endptr = png_ptr->chunkdata + slength; /* We need to have at least 12 bytes after the purpose string * in order to get the parameter information. */ if (endptr <= buf + 12) { png_warning(png_ptr, "Invalid pCAL data"); png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; return; } png_debug(3, "Reading pCAL X0, X1, type, nparams, and units"); X0 = png_get_int_32((png_bytep)buf+1); X1 = png_get_int_32((png_bytep)buf+5); type = buf[9]; nparams = buf[10]; units = buf + 11; png_debug(3, "Checking pCAL equation type and number of parameters"); /* Check that we have the right number of parameters for known * equation types. */ if ((type == PNG_EQUATION_LINEAR && nparams != 2) || (type == PNG_EQUATION_BASE_E && nparams != 3) || (type == PNG_EQUATION_ARBITRARY && nparams != 3) || (type == PNG_EQUATION_HYPERBOLIC && nparams != 4)) { png_warning(png_ptr, "Invalid pCAL parameters for equation type"); png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; return; } else if (type >= PNG_EQUATION_LAST) { png_warning(png_ptr, "Unrecognized equation type for pCAL chunk"); } for (buf = units; *buf; buf++) /* Empty loop to move past the units string. */ ; png_debug(3, "Allocating pCAL parameters array"); params = (png_charpp)png_malloc_warn(png_ptr, (png_size_t)(nparams * png_sizeof(png_charp))); if (params == NULL) { png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; png_warning(png_ptr, "No memory for pCAL params"); return; } /* Get pointers to the start of each parameter string. */ for (i = 0; i < (int)nparams; i++) { buf++; /* Skip the null string terminator from previous parameter. */ png_debug1(3, "Reading pCAL parameter %d", i); for (params[i] = buf; buf <= endptr && *buf != 0x00; buf++) /* Empty loop to move past each parameter string */ ; /* Make sure we haven't run out of data yet */ if (buf > endptr) { png_warning(png_ptr, "Invalid pCAL data"); png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; png_free(png_ptr, params); return; } } png_set_pCAL(png_ptr, info_ptr, png_ptr->chunkdata, X0, X1, type, nparams, units, params); png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; png_free(png_ptr, params); } #endif #ifdef PNG_READ_sCAL_SUPPORTED /* Read the sCAL chunk */ void /* PRIVATE */ png_handle_sCAL(png_structp png_ptr, png_infop info_ptr, png_uint_32 length) { png_size_t slength, i; int state; png_debug(1, "in png_handle_sCAL"); if (!(png_ptr->mode & PNG_HAVE_IHDR)) png_error(png_ptr, "Missing IHDR before sCAL"); else if (png_ptr->mode & PNG_HAVE_IDAT) { png_warning(png_ptr, "Invalid sCAL after IDAT"); png_crc_finish(png_ptr, length); return; } else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sCAL)) { png_warning(png_ptr, "Duplicate sCAL chunk"); png_crc_finish(png_ptr, length); return; } /* Need unit type, width, \0, height: minimum 4 bytes */ else if (length < 4) { png_warning(png_ptr, "sCAL chunk too short"); png_crc_finish(png_ptr, length); return; } png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)", length + 1); png_ptr->chunkdata = (png_charp)png_malloc_warn(png_ptr, length + 1); if (png_ptr->chunkdata == NULL) { png_warning(png_ptr, "Out of memory while processing sCAL chunk"); png_crc_finish(png_ptr, length); return; } slength = (png_size_t)length; png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength); png_ptr->chunkdata[slength] = 0x00; /* Null terminate the last string */ if (png_crc_finish(png_ptr, 0)) { png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; return; } /* Validate the unit. */ if (png_ptr->chunkdata[0] != 1 && png_ptr->chunkdata[0] != 2) { png_warning(png_ptr, "Invalid sCAL ignored: invalid unit"); png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; return; } /* Validate the ASCII numbers, need two ASCII numbers separated by * a '\0' and they need to fit exactly in the chunk data. */ i = 1; state = 0; if (!png_check_fp_number(png_ptr->chunkdata, slength, &state, &i) || i >= slength || png_ptr->chunkdata[i++] != 0) png_warning(png_ptr, "Invalid sCAL chunk ignored: bad width format"); else if (!PNG_FP_IS_POSITIVE(state)) png_warning(png_ptr, "Invalid sCAL chunk ignored: non-positive width"); else { png_size_t heighti = i; state = 0; if (!png_check_fp_number(png_ptr->chunkdata, slength, &state, &i) || i != slength) png_warning(png_ptr, "Invalid sCAL chunk ignored: bad height format"); else if (!PNG_FP_IS_POSITIVE(state)) png_warning(png_ptr, "Invalid sCAL chunk ignored: non-positive height"); else /* This is the (only) success case. */ png_set_sCAL_s(png_ptr, info_ptr, png_ptr->chunkdata[0], png_ptr->chunkdata+1, png_ptr->chunkdata+heighti); } /* Clean up - just free the temporarily allocated buffer. */ png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; } #endif #ifdef PNG_READ_tIME_SUPPORTED void /* PRIVATE */ png_handle_tIME(png_structp png_ptr, png_infop info_ptr, png_uint_32 length) { png_byte buf[7]; png_time mod_time; png_debug(1, "in png_handle_tIME"); if (!(png_ptr->mode & PNG_HAVE_IHDR)) png_error(png_ptr, "Out of place tIME chunk"); else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME)) { png_warning(png_ptr, "Duplicate tIME chunk"); png_crc_finish(png_ptr, length); return; } if (png_ptr->mode & PNG_HAVE_IDAT) png_ptr->mode |= PNG_AFTER_IDAT; if (length != 7) { png_warning(png_ptr, "Incorrect tIME chunk length"); png_crc_finish(png_ptr, length); return; } png_crc_read(png_ptr, buf, 7); if (png_crc_finish(png_ptr, 0)) return; mod_time.second = buf[6]; mod_time.minute = buf[5]; mod_time.hour = buf[4]; mod_time.day = buf[3]; mod_time.month = buf[2]; mod_time.year = png_get_uint_16(buf); png_set_tIME(png_ptr, info_ptr, &mod_time); } #endif #ifdef PNG_READ_tEXt_SUPPORTED /* Note: this does not properly handle chunks that are > 64K under DOS */ void /* PRIVATE */ png_handle_tEXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length) { png_textp text_ptr; png_charp key; png_charp text; png_uint_32 skip = 0; png_size_t slength; int ret; png_debug(1, "in png_handle_tEXt"); #ifdef PNG_USER_LIMITS_SUPPORTED if (png_ptr->user_chunk_cache_max != 0) { if (png_ptr->user_chunk_cache_max == 1) { png_crc_finish(png_ptr, length); return; } if (--png_ptr->user_chunk_cache_max == 1) { png_warning(png_ptr, "No space in chunk cache for tEXt"); png_crc_finish(png_ptr, length); return; } } #endif if (!(png_ptr->mode & PNG_HAVE_IHDR)) png_error(png_ptr, "Missing IHDR before tEXt"); if (png_ptr->mode & PNG_HAVE_IDAT) png_ptr->mode |= PNG_AFTER_IDAT; #ifdef PNG_MAX_MALLOC_64K if (length > (png_uint_32)65535L) { png_warning(png_ptr, "tEXt chunk too large to fit in memory"); skip = length - (png_uint_32)65535L; length = (png_uint_32)65535L; } #endif png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = (png_charp)png_malloc_warn(png_ptr, length + 1); if (png_ptr->chunkdata == NULL) { png_warning(png_ptr, "No memory to process text chunk"); return; } slength = (png_size_t)length; png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength); if (png_crc_finish(png_ptr, skip)) { png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; return; } key = png_ptr->chunkdata; key[slength] = 0x00; for (text = key; *text; text++) /* Empty loop to find end of key */ ; if (text != key + slength) text++; text_ptr = (png_textp)png_malloc_warn(png_ptr, png_sizeof(png_text)); if (text_ptr == NULL) { png_warning(png_ptr, "Not enough memory to process text chunk"); png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; return; } text_ptr->compression = PNG_TEXT_COMPRESSION_NONE; text_ptr->key = key; text_ptr->lang = NULL; text_ptr->lang_key = NULL; text_ptr->itxt_length = 0; text_ptr->text = text; text_ptr->text_length = png_strlen(text); ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1); png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; png_free(png_ptr, text_ptr); if (ret) png_warning(png_ptr, "Insufficient memory to process text chunk"); } #endif #ifdef PNG_READ_zTXt_SUPPORTED /* Note: this does not correctly handle chunks that are > 64K under DOS */ void /* PRIVATE */ png_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length) { png_textp text_ptr; png_charp text; int comp_type; int ret; png_size_t slength, prefix_len, data_len; png_debug(1, "in png_handle_zTXt"); #ifdef PNG_USER_LIMITS_SUPPORTED if (png_ptr->user_chunk_cache_max != 0) { if (png_ptr->user_chunk_cache_max == 1) { png_crc_finish(png_ptr, length); return; } if (--png_ptr->user_chunk_cache_max == 1) { png_warning(png_ptr, "No space in chunk cache for zTXt"); png_crc_finish(png_ptr, length); return; } } #endif if (!(png_ptr->mode & PNG_HAVE_IHDR)) png_error(png_ptr, "Missing IHDR before zTXt"); if (png_ptr->mode & PNG_HAVE_IDAT) png_ptr->mode |= PNG_AFTER_IDAT; #ifdef PNG_MAX_MALLOC_64K /* We will no doubt have problems with chunks even half this size, but * there is no hard and fast rule to tell us where to stop. */ if (length > (png_uint_32)65535L) { png_warning(png_ptr, "zTXt chunk too large to fit in memory"); png_crc_finish(png_ptr, length); return; } #endif png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = (png_charp)png_malloc_warn(png_ptr, length + 1); if (png_ptr->chunkdata == NULL) { png_warning(png_ptr, "Out of memory processing zTXt chunk"); return; } slength = (png_size_t)length; png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength); if (png_crc_finish(png_ptr, 0)) { png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; return; } png_ptr->chunkdata[slength] = 0x00; for (text = png_ptr->chunkdata; *text; text++) /* Empty loop */ ; /* zTXt must have some text after the chunkdataword */ if (text >= png_ptr->chunkdata + slength - 2) { png_warning(png_ptr, "Truncated zTXt chunk"); png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; return; } else { comp_type = *(++text); if (comp_type != PNG_TEXT_COMPRESSION_zTXt) { png_warning(png_ptr, "Unknown compression type in zTXt chunk"); comp_type = PNG_TEXT_COMPRESSION_zTXt; } text++; /* Skip the compression_method byte */ } prefix_len = text - png_ptr->chunkdata; png_decompress_chunk(png_ptr, comp_type, (png_size_t)length, prefix_len, &data_len); text_ptr = (png_textp)png_malloc_warn(png_ptr, png_sizeof(png_text)); if (text_ptr == NULL) { png_warning(png_ptr, "Not enough memory to process zTXt chunk"); png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; return; } text_ptr->compression = comp_type; text_ptr->key = png_ptr->chunkdata; text_ptr->lang = NULL; text_ptr->lang_key = NULL; text_ptr->itxt_length = 0; text_ptr->text = png_ptr->chunkdata + prefix_len; text_ptr->text_length = data_len; ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1); png_free(png_ptr, text_ptr); png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; if (ret) png_error(png_ptr, "Insufficient memory to store zTXt chunk"); } #endif #ifdef PNG_READ_iTXt_SUPPORTED /* Note: this does not correctly handle chunks that are > 64K under DOS */ void /* PRIVATE */ png_handle_iTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length) { png_textp text_ptr; png_charp key, lang, text, lang_key; int comp_flag; int comp_type = 0; int ret; png_size_t slength, prefix_len, data_len; png_debug(1, "in png_handle_iTXt"); #ifdef PNG_USER_LIMITS_SUPPORTED if (png_ptr->user_chunk_cache_max != 0) { if (png_ptr->user_chunk_cache_max == 1) { png_crc_finish(png_ptr, length); return; } if (--png_ptr->user_chunk_cache_max == 1) { png_warning(png_ptr, "No space in chunk cache for iTXt"); png_crc_finish(png_ptr, length); return; } } #endif if (!(png_ptr->mode & PNG_HAVE_IHDR)) png_error(png_ptr, "Missing IHDR before iTXt"); if (png_ptr->mode & PNG_HAVE_IDAT) png_ptr->mode |= PNG_AFTER_IDAT; #ifdef PNG_MAX_MALLOC_64K /* We will no doubt have problems with chunks even half this size, but * there is no hard and fast rule to tell us where to stop. */ if (length > (png_uint_32)65535L) { png_warning(png_ptr, "iTXt chunk too large to fit in memory"); png_crc_finish(png_ptr, length); return; } #endif png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = (png_charp)png_malloc_warn(png_ptr, length + 1); if (png_ptr->chunkdata == NULL) { png_warning(png_ptr, "No memory to process iTXt chunk"); return; } slength = (png_size_t)length; png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength); if (png_crc_finish(png_ptr, 0)) { png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; return; } png_ptr->chunkdata[slength] = 0x00; for (lang = png_ptr->chunkdata; *lang; lang++) /* Empty loop */ ; lang++; /* Skip NUL separator */ /* iTXt must have a language tag (possibly empty), two compression bytes, * translated keyword (possibly empty), and possibly some text after the * keyword */ if (lang >= png_ptr->chunkdata + slength - 3) { png_warning(png_ptr, "Truncated iTXt chunk"); png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; return; } else { comp_flag = *lang++; comp_type = *lang++; } for (lang_key = lang; *lang_key; lang_key++) /* Empty loop */ ; lang_key++; /* Skip NUL separator */ if (lang_key >= png_ptr->chunkdata + slength) { png_warning(png_ptr, "Truncated iTXt chunk"); png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; return; } for (text = lang_key; *text; text++) /* Empty loop */ ; text++; /* Skip NUL separator */ if (text >= png_ptr->chunkdata + slength) { png_warning(png_ptr, "Malformed iTXt chunk"); png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; return; } prefix_len = text - png_ptr->chunkdata; key=png_ptr->chunkdata; if (comp_flag) png_decompress_chunk(png_ptr, comp_type, (size_t)length, prefix_len, &data_len); else data_len = png_strlen(png_ptr->chunkdata + prefix_len); text_ptr = (png_textp)png_malloc_warn(png_ptr, png_sizeof(png_text)); if (text_ptr == NULL) { png_warning(png_ptr, "Not enough memory to process iTXt chunk"); png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; return; } text_ptr->compression = (int)comp_flag + 1; text_ptr->lang_key = png_ptr->chunkdata + (lang_key - key); text_ptr->lang = png_ptr->chunkdata + (lang - key); text_ptr->itxt_length = data_len; text_ptr->text_length = 0; text_ptr->key = png_ptr->chunkdata; text_ptr->text = png_ptr->chunkdata + prefix_len; ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1); png_free(png_ptr, text_ptr); png_free(png_ptr, png_ptr->chunkdata); png_ptr->chunkdata = NULL; if (ret) png_error(png_ptr, "Insufficient memory to store iTXt chunk"); } #endif /* This function is called when we haven't found a handler for a * chunk. If there isn't a problem with the chunk itself (ie bad * chunk name, CRC, or a critical chunk), the chunk is silently ignored * -- unless the PNG_FLAG_UNKNOWN_CHUNKS_SUPPORTED flag is on in which * case it will be saved away to be written out later. */ void /* PRIVATE */ png_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32 length) { png_uint_32 skip = 0; png_debug(1, "in png_handle_unknown"); #ifdef PNG_USER_LIMITS_SUPPORTED if (png_ptr->user_chunk_cache_max != 0) { if (png_ptr->user_chunk_cache_max == 1) { png_crc_finish(png_ptr, length); return; } if (--png_ptr->user_chunk_cache_max == 1) { png_warning(png_ptr, "No space in chunk cache for unknown chunk"); png_crc_finish(png_ptr, length); return; } } #endif if (png_ptr->mode & PNG_HAVE_IDAT) { if (png_ptr->chunk_name != png_IDAT) png_ptr->mode |= PNG_AFTER_IDAT; } if (PNG_CHUNK_CRITICAL(png_ptr->chunk_name)) { #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED if (png_chunk_unknown_handling(png_ptr, png_ptr->chunk_name) != PNG_HANDLE_CHUNK_ALWAYS #ifdef PNG_READ_USER_CHUNKS_SUPPORTED && png_ptr->read_user_chunk_fn == NULL #endif ) #endif png_chunk_error(png_ptr, "unknown critical chunk"); } #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED if ((png_ptr->flags & PNG_FLAG_KEEP_UNKNOWN_CHUNKS) #ifdef PNG_READ_USER_CHUNKS_SUPPORTED || (png_ptr->read_user_chunk_fn != NULL) #endif ) { #ifdef PNG_MAX_MALLOC_64K if (length > 65535) { png_warning(png_ptr, "unknown chunk too large to fit in memory"); skip = length - 65535; length = 65535; } #endif /* TODO: this code is very close to the unknown handling in pngpread.c, * maybe it can be put into a common utility routine? * png_struct::unknown_chunk is just used as a temporary variable, along * with the data into which the chunk is read. These can be eliminated. */ PNG_CSTRING_FROM_CHUNK(png_ptr->unknown_chunk.name, png_ptr->chunk_name); png_ptr->unknown_chunk.size = (png_size_t)length; if (length == 0) png_ptr->unknown_chunk.data = NULL; else { png_ptr->unknown_chunk.data = (png_bytep)png_malloc(png_ptr, length); png_crc_read(png_ptr, png_ptr->unknown_chunk.data, length); } #ifdef PNG_READ_USER_CHUNKS_SUPPORTED if (png_ptr->read_user_chunk_fn != NULL) { /* Callback to user unknown chunk handler */ int ret; ret = (*(png_ptr->read_user_chunk_fn)) (png_ptr, &png_ptr->unknown_chunk); if (ret < 0) png_chunk_error(png_ptr, "error in user chunk"); if (ret == 0) { if (PNG_CHUNK_CRITICAL(png_ptr->chunk_name)) { #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED if (png_chunk_unknown_handling(png_ptr, png_ptr->chunk_name) != PNG_HANDLE_CHUNK_ALWAYS) #endif png_chunk_error(png_ptr, "unknown critical chunk"); } png_set_unknown_chunks(png_ptr, info_ptr, &png_ptr->unknown_chunk, 1); } } else #endif png_set_unknown_chunks(png_ptr, info_ptr, &png_ptr->unknown_chunk, 1); png_free(png_ptr, png_ptr->unknown_chunk.data); png_ptr->unknown_chunk.data = NULL; } else #endif skip = length; png_crc_finish(png_ptr, skip); #ifndef PNG_READ_USER_CHUNKS_SUPPORTED PNG_UNUSED(info_ptr) /* Quiet compiler warnings about unused info_ptr */ #endif } /* This function is called to verify that a chunk name is valid. * This function can't have the "critical chunk check" incorporated * into it, since in the future we will need to be able to call user * functions to handle unknown critical chunks after we check that * the chunk name itself is valid. */ /* Bit hacking: the test for an invalid byte in the 4 byte chunk name is: * * ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97)) */ void /* PRIVATE */ png_check_chunk_name(png_structp png_ptr, png_uint_32 chunk_name) { int i; png_debug(1, "in png_check_chunk_name"); for (i=1; i<=4; ++i) { int c = chunk_name & 0xff; if (c < 65 || c > 122 || (c > 90 && c < 97)) png_chunk_error(png_ptr, "invalid chunk type"); chunk_name >>= 8; } } /* Combines the row recently read in with the existing pixels in the * row. This routine takes care of alpha and transparency if requested. * This routine also handles the two methods of progressive display * of interlaced images, depending on the mask value. * The mask value describes which pixels are to be combined with * the row. The pattern always repeats every 8 pixels, so just 8 * bits are needed. A one indicates the pixel is to be combined, * a zero indicates the pixel is to be skipped. This is in addition * to any alpha or transparency value associated with the pixel. If * you want all pixels to be combined, pass 0xff (255) in mask. */ void /* PRIVATE */ png_combine_row(png_structp png_ptr, png_bytep row, int mask) { int pixel_depth = png_ptr->transformed_pixel_depth; 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, png_ptr->width)) png_error(png_ptr, "internal row size calculation error"); if (mask == 0xff) { png_memcpy(row, png_ptr->row_buf + 1, PNG_ROWBYTES(pixel_depth, png_ptr->width)); } else { switch (pixel_depth) { case 1: { png_bytep sp = png_ptr->row_buf + 1; png_bytep dp = row; int s_inc, s_start, s_end; int m = 0x80; int shift; png_uint_32 i; png_uint_32 row_width = png_ptr->width; #ifdef PNG_READ_PACKSWAP_SUPPORTED if (png_ptr->transformations & PNG_PACKSWAP) { s_start = 0; s_end = 7; s_inc = 1; } else #endif { s_start = 7; s_end = 0; s_inc = -1; } shift = s_start; for (i = 0; i < row_width; i++) { if (m & mask) { int value; value = (*sp >> shift) & 0x01; *dp &= (png_byte)((0x7f7f >> (7 - shift)) & 0xff); *dp |= (png_byte)(value << shift); } if (shift == s_end) { shift = s_start; sp++; dp++; } else shift += s_inc; if (m == 1) m = 0x80; else m >>= 1; } break; } case 2: { png_bytep sp = png_ptr->row_buf + 1; png_bytep dp = row; int s_start, s_end, s_inc; int m = 0x80; int shift; png_uint_32 i; png_uint_32 row_width = png_ptr->width; int value; #ifdef PNG_READ_PACKSWAP_SUPPORTED if (png_ptr->transformations & PNG_PACKSWAP) { s_start = 0; s_end = 6; s_inc = 2; } else #endif { s_start = 6; s_end = 0; s_inc = -2; } shift = s_start; for (i = 0; i < row_width; i++) { if (m & mask) { value = (*sp >> shift) & 0x03; *dp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff); *dp |= (png_byte)(value << shift); } if (shift == s_end) { shift = s_start; sp++; dp++; } else shift += s_inc; if (m == 1) m = 0x80; else m >>= 1; } break; } case 4: { png_bytep sp = png_ptr->row_buf + 1; png_bytep dp = row; int s_start, s_end, s_inc; int m = 0x80; int shift; png_uint_32 i; png_uint_32 row_width = png_ptr->width; int value; #ifdef PNG_READ_PACKSWAP_SUPPORTED if (png_ptr->transformations & PNG_PACKSWAP) { s_start = 0; s_end = 4; s_inc = 4; } else #endif { s_start = 4; s_end = 0; s_inc = -4; } shift = s_start; for (i = 0; i < row_width; i++) { if (m & mask) { value = (*sp >> shift) & 0xf; *dp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff); *dp |= (png_byte)(value << shift); } if (shift == s_end) { shift = s_start; sp++; dp++; } else shift += s_inc; if (m == 1) m = 0x80; else m >>= 1; } break; } default: { png_bytep sp = png_ptr->row_buf + 1; png_bytep dp = row; png_size_t pixel_bytes = pixel_depth >> 3; png_uint_32 i; png_uint_32 row_width = png_ptr->width; png_byte m = 0x80; for (i = 0; i < row_width; i++) { if (m & mask) { /* Prior to libpng-1.5.6 we used memcpy(), but limited * experiments show that this simple loop can be * significantly faster. */ int j; for (j = pixel_bytes; j; --j) *(dp++) = *(sp++); } else { sp += pixel_bytes; dp += pixel_bytes; } if (m == 1) m = 0x80; else m >>= 1; } break; } } } } #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) & 0xf); int j; for (j = 0; j < jstop; j++) { *dp &= (png_byte)((0xf0f >> (4 - dshift)) & 0xff); *dp |= (png_byte)(v << dshift); if (dshift == s_end) { dshift = s_start; dp--; } else dshift += s_inc; } if (sshift == s_end) { sshift = s_start; sp--; } else sshift += s_inc; } break; } default: { png_size_t pixel_bytes = (row_info->pixel_depth >> 3); png_bytep sp = row + (png_size_t)(row_info->width - 1) * pixel_bytes; png_bytep dp = row + (png_size_t)(final_width - 1) * pixel_bytes; int jstop = png_pass_inc[pass]; png_uint_32 i; for (i = 0; i < row_info->width; i++) { png_byte v[8]; int j; png_memcpy(v, sp, pixel_bytes); for (j = 0; j < jstop; j++) { png_memcpy(dp, v, pixel_bytes); dp -= pixel_bytes; } sp -= pixel_bytes; } break; } } row_info->width = final_width; row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, final_width); } #ifndef PNG_READ_PACKSWAP_SUPPORTED PNG_UNUSED(transformations) /* Silence compiler warning */ #endif } #endif /* PNG_READ_INTERLACING_SUPPORTED */ /* 1.5.6: Changed to just take a png_row_info (not png_ptr) and to ignore bad * adaptive filter bytes. */ void /* PRIVATE */ png_read_filter_row(png_row_infop row_info, png_bytep row, png_const_bytep prev_row, int filter) { switch (filter) { case PNG_FILTER_VALUE_NONE: break; case PNG_FILTER_VALUE_SUB: { png_size_t i; png_size_t istop = row_info->rowbytes; unsigned int bpp = (row_info->pixel_depth + 7) >> 3; png_bytep rp = row + bpp; png_bytep lp = row; for (i = bpp; i < istop; i++) { *rp = (png_byte)(((int)(*rp) + (int)(*lp++)) & 0xff); rp++; } break; } case PNG_FILTER_VALUE_UP: { 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++; } break; } case PNG_FILTER_VALUE_AVG: { png_size_t i; png_bytep rp = row; png_const_bytep pp = prev_row; png_bytep lp = row; unsigned int bpp = (row_info->pixel_depth + 7) >> 3; png_size_t istop = row_info->rowbytes - bpp; for (i = 0; i < bpp; i++) { *rp = (png_byte)(((int)(*rp) + ((int)(*pp++) / 2 )) & 0xff); rp++; } for (i = 0; i < istop; i++) { *rp = (png_byte)(((int)(*rp) + (int)(*pp++ + *lp++) / 2 ) & 0xff); rp++; } break; } case PNG_FILTER_VALUE_PAETH: { png_size_t i; png_bytep rp = row; png_const_bytep pp = prev_row; png_bytep lp = row; png_const_bytep cp = 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++)) & 0xff); rp++; } for (i = 0; i < istop; i++) /* Use leftover rp,pp */ { int a, b, c, pa, pb, pc, p; a = *lp++; b = *pp++; c = *cp++; 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 (pa <= pb && pa <= pc) p = a; else if (pb <= pc) p = b; else p = c; */ p = (pa <= pb && pa <= pc) ? a : (pb <= pc) ? b : c; *rp = (png_byte)(((int)(*rp) + p) & 0xff); rp++; } break; } default: /* NOT REACHED */ break; } } #ifdef PNG_SEQUENTIAL_READ_SUPPORTED void /* PRIVATE */ png_read_finish_row(png_structp png_ptr) { #ifdef PNG_READ_INTERLACING_SUPPORTED /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ /* Start of interlace block */ static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; /* Offset to next interlace block */ static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; /* Start of interlace block in the y direction */ static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1}; /* Offset to next interlace block in the y direction */ static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2}; #endif /* PNG_READ_INTERLACING_SUPPORTED */ png_debug(1, "in png_read_finish_row"); png_ptr->row_number++; if (png_ptr->row_number < png_ptr->num_rows) return; #ifdef PNG_READ_INTERLACING_SUPPORTED if (png_ptr->interlaced) { png_ptr->row_number = 0; /* TO DO: don't do this if prev_row isn't needed (requires * read-ahead of the next row's filter byte. */ png_memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1); do { png_ptr->pass++; if (png_ptr->pass >= 7) break; png_ptr->iwidth = (png_ptr->width + png_pass_inc[png_ptr->pass] - 1 - png_pass_start[png_ptr->pass]) / png_pass_inc[png_ptr->pass]; if (!(png_ptr->transformations & PNG_INTERLACE)) { png_ptr->num_rows = (png_ptr->height + png_pass_yinc[png_ptr->pass] - 1 - png_pass_ystart[png_ptr->pass]) / png_pass_yinc[png_ptr->pass]; } else /* if (png_ptr->transformations & PNG_INTERLACE) */ break; /* libpng deinterlacing sees every row */ } while (png_ptr->num_rows == 0 || png_ptr->iwidth == 0); if (png_ptr->pass < 7) return; } #endif /* PNG_READ_INTERLACING_SUPPORTED */ if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED)) { char extra; int ret; png_ptr->zstream.next_out = (Byte *)&extra; png_ptr->zstream.avail_out = (uInt)1; for (;;) { if (!(png_ptr->zstream.avail_in)) { while (!png_ptr->idat_size) { png_crc_finish(png_ptr, 0); png_ptr->idat_size = png_read_chunk_header(png_ptr); if (png_ptr->chunk_name != png_IDAT) png_error(png_ptr, "Not enough image data"); } png_ptr->zstream.avail_in = (uInt)png_ptr->zbuf_size; png_ptr->zstream.next_in = png_ptr->zbuf; if (png_ptr->zbuf_size > png_ptr->idat_size) png_ptr->zstream.avail_in = (uInt)png_ptr->idat_size; png_crc_read(png_ptr, png_ptr->zbuf, png_ptr->zstream.avail_in); png_ptr->idat_size -= png_ptr->zstream.avail_in; } ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH); if (ret == Z_STREAM_END) { if (!(png_ptr->zstream.avail_out) || png_ptr->zstream.avail_in || png_ptr->idat_size) png_warning(png_ptr, "Extra compressed data"); png_ptr->mode |= PNG_AFTER_IDAT; png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED; break; } if (ret != Z_OK) png_error(png_ptr, png_ptr->zstream.msg ? png_ptr->zstream.msg : "Decompression Error"); if (!(png_ptr->zstream.avail_out)) { png_warning(png_ptr, "Extra compressed data"); png_ptr->mode |= PNG_AFTER_IDAT; png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED; break; } } png_ptr->zstream.avail_out = 0; } if (png_ptr->idat_size || png_ptr->zstream.avail_in) png_warning(png_ptr, "Extra compression data"); inflateReset(&png_ptr->zstream); png_ptr->mode |= PNG_AFTER_IDAT; } #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */ void /* PRIVATE */ png_read_start_row(png_structp png_ptr) { #ifdef PNG_READ_INTERLACING_SUPPORTED /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ /* Start of interlace block */ static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; /* Offset to next interlace block */ static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; /* Start of interlace block in the y direction */ static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1}; /* Offset to next interlace block in the y direction */ static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2}; #endif int max_pixel_depth; png_size_t row_bytes; png_debug(1, "in png_read_start_row"); png_ptr->zstream.avail_in = 0; #ifdef PNG_READ_TRANSFORMS_SUPPORTED png_init_read_transformations(png_ptr); #endif #ifdef PNG_READ_INTERLACING_SUPPORTED if (png_ptr->interlaced) { if (!(png_ptr->transformations & PNG_INTERLACE)) png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 - png_pass_ystart[0]) / png_pass_yinc[0]; else png_ptr->num_rows = png_ptr->height; png_ptr->iwidth = (png_ptr->width + png_pass_inc[png_ptr->pass] - 1 - png_pass_start[png_ptr->pass]) / png_pass_inc[png_ptr->pass]; } else #endif /* PNG_READ_INTERLACING_SUPPORTED */ { png_ptr->num_rows = png_ptr->height; png_ptr->iwidth = png_ptr->width; } max_pixel_depth = png_ptr->pixel_depth; #ifdef PNG_READ_PACK_SUPPORTED if ((png_ptr->transformations & PNG_PACK) && png_ptr->bit_depth < 8) max_pixel_depth = 8; #endif #ifdef PNG_READ_EXPAND_SUPPORTED if (png_ptr->transformations & PNG_EXPAND) { if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) { if (png_ptr->num_trans) max_pixel_depth = 32; else max_pixel_depth = 24; } else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY) { if (max_pixel_depth < 8) max_pixel_depth = 8; if (png_ptr->num_trans) max_pixel_depth *= 2; } else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB) { if (png_ptr->num_trans) { max_pixel_depth *= 4; max_pixel_depth /= 3; } } } #endif #ifdef PNG_READ_EXPAND_16_SUPPORTED if (png_ptr->transformations & PNG_EXPAND_16) { # ifdef PNG_READ_EXPAND_SUPPORTED /* In fact it is an error if it isn't supported, but checking is * the safe way. */ if (png_ptr->transformations & PNG_EXPAND) { if (png_ptr->bit_depth < 16) max_pixel_depth *= 2; } else # endif png_ptr->transformations &= ~PNG_EXPAND_16; } #endif #ifdef PNG_READ_FILLER_SUPPORTED if (png_ptr->transformations & (PNG_FILLER)) { if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) max_pixel_depth = 32; else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY) { if (max_pixel_depth <= 8) max_pixel_depth = 16; else max_pixel_depth = 32; } else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB) { if (max_pixel_depth <= 32) max_pixel_depth = 32; else max_pixel_depth = 64; } } #endif #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED if (png_ptr->transformations & PNG_GRAY_TO_RGB) { if ( #ifdef PNG_READ_EXPAND_SUPPORTED (png_ptr->num_trans && (png_ptr->transformations & PNG_EXPAND)) || #endif #ifdef PNG_READ_FILLER_SUPPORTED (png_ptr->transformations & (PNG_FILLER)) || #endif png_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) { if (max_pixel_depth <= 16) max_pixel_depth = 32; else max_pixel_depth = 64; } else { if (max_pixel_depth <= 8) { if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA) max_pixel_depth = 32; else max_pixel_depth = 24; } else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA) max_pixel_depth = 64; else max_pixel_depth = 48; } } #endif #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) && \ defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) if (png_ptr->transformations & PNG_USER_TRANSFORM) { int user_pixel_depth = png_ptr->user_transform_depth * png_ptr->user_transform_channels; if (user_pixel_depth > max_pixel_depth) max_pixel_depth = user_pixel_depth; } #endif /* This value is stored in png_struct and double checked in the row read * code. */ png_ptr->maximum_pixel_depth = (png_byte)max_pixel_depth; png_ptr->transformed_pixel_depth = 0; /* calculated on demand */ /* Align the width on the next larger 8 pixels. Mainly used * for interlacing */ row_bytes = ((png_ptr->width + 7) & ~((png_uint_32)7)); /* Calculate the maximum bytes needed, adding a byte and a pixel * for safety's sake */ row_bytes = PNG_ROWBYTES(max_pixel_depth, row_bytes) + 1 + ((max_pixel_depth + 7) >> 3); #ifdef PNG_MAX_MALLOC_64K if (row_bytes > (png_uint_32)65536L) png_error(png_ptr, "This image requires a row greater than 64KB"); #endif if (row_bytes + 48 > png_ptr->old_big_row_buf_size) { png_free(png_ptr, png_ptr->big_row_buf); 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->old_big_row_buf_size = 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. */ png_ptr->row_buf = png_ptr->big_row_buf + 32 - (((png_alloc_size_t)png_ptr->big_row_buf + 15) & 0x0F); png_ptr->old_big_row_buf_size = row_bytes + 48; #else /* Use 32 bytes of padding before and 16 bytes after row_buf. */ png_ptr->row_buf = png_ptr->big_row_buf + 32; #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"); if (png_ptr->rowbytes + 1 > png_ptr->old_prev_row_size) { png_free(png_ptr, png_ptr->prev_row); png_ptr->prev_row = (png_bytep)png_malloc(png_ptr, png_ptr->rowbytes + 1); png_ptr->old_prev_row_size = png_ptr->rowbytes + 1; } 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 */