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Diffstat (limited to 'plugingui/png/pngrutil.c')
| -rw-r--r-- | plugingui/png/pngrutil.c | 4159 |
1 files changed, 4159 insertions, 0 deletions
diff --git a/plugingui/png/pngrutil.c b/plugingui/png/pngrutil.c new file mode 100644 index 0000000..4ef05fe --- /dev/null +++ b/plugingui/png/pngrutil.c @@ -0,0 +1,4159 @@ + +/* pngrutil.c - utilities to read a PNG file + * + * Last changed in libpng 1.5.10 [March 8, 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_USER_LIMITS_SUPPORTED + || (png_ptr->user_chunk_malloc_max && + (prefix_size + expanded_size >= png_ptr->user_chunk_malloc_max - 1)) +#else + || ((PNG_USER_CHUNK_MALLOC_MAX > 0) && + prefix_size + expanded_size >= PNG_USER_CHUNK_MALLOC_MAX - 1) +#endif + ) + png_warning(png_ptr, "Exceeded size limit while expanding chunk"); + + /* If the size is zero either there was an error and a message + * has already been output (warning) or the size really is zero + * and we have nothing to do - the code will exit through the + * error case below. + */ + else if (expanded_size > 0) + { + /* Success (maybe) - really uncompress the chunk. */ + png_size_t new_size = 0; + png_charp text = (png_charp)png_malloc_warn(png_ptr, + prefix_size + expanded_size + 1); + + 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 ((png_ptr->mode & PNG_HAVE_iCCP) || (info_ptr != NULL && + (info_ptr->valid & (PNG_INFO_iCCP|PNG_INFO_sRGB)))) + { + png_warning(png_ptr, "Duplicate iCCP chunk"); + png_crc_finish(png_ptr, length); + return; + } + + png_ptr->mode |= PNG_HAVE_iCCP; + +#ifdef PNG_MAX_MALLOC_64K + if (length > (png_uint_32)65535L) + { + png_warning(png_ptr, "iCCP chunk too large to fit in memory"); + skip = length - (png_uint_32)65535L; + length = (png_uint_32)65535L; + } +#endif + + png_free(png_ptr, png_ptr->chunkdata); + png_ptr->chunkdata = (png_charp)png_malloc(png_ptr, length + 1); + slength = length; + png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength); + + if (png_crc_finish(png_ptr, skip)) + { + png_free(png_ptr, png_ptr->chunkdata); + png_ptr->chunkdata = NULL; + return; + } + + png_ptr->chunkdata[slength] = 0x00; + + for (profile = png_ptr->chunkdata; *profile; profile++) + /* Empty loop to find end of name */ ; + + ++profile; + + /* There should be at least one zero (the compression type byte) + * following the separator, and we should be on it + */ + if (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); + return; + } + + if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) + truelen = 1; + + else if (png_ptr->color_type & PNG_COLOR_MASK_COLOR) + truelen = 6; + + else + truelen = 2; + + if (length != truelen) + { + png_warning(png_ptr, "Incorrect bKGD chunk length"); + png_crc_finish(png_ptr, length); + return; + } + + png_crc_read(png_ptr, buf, truelen); + + if (png_crc_finish(png_ptr, 0)) + return; + + /* We convert the index value into RGB components so that we can allow + * arbitrary RGB values for background when we have transparency, and + * so it is easy to determine the RGB values of the background color + * from the info_ptr struct. + */ + if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) + { + background.index = buf[0]; + + if (info_ptr && info_ptr->num_palette) + { + if (buf[0] >= info_ptr->num_palette) + { + png_warning(png_ptr, "Incorrect bKGD chunk index value"); + return; + } + + background.red = (png_uint_16)png_ptr->palette[buf[0]].red; + background.green = (png_uint_16)png_ptr->palette[buf[0]].green; + background.blue = (png_uint_16)png_ptr->palette[buf[0]].blue; + } + + else + background.red = background.green = background.blue = 0; + + background.gray = 0; + } + + else if (!(png_ptr->color_type & PNG_COLOR_MASK_COLOR)) /* GRAY */ + { + background.index = 0; + background.red = + background.green = + background.blue = + background.gray = png_get_uint_16(buf); + } + + else + { + background.index = 0; + background.red = png_get_uint_16(buf); + background.green = png_get_uint_16(buf + 2); + background.blue = png_get_uint_16(buf + 4); + background.gray = 0; + } + + png_set_bKGD(png_ptr, info_ptr, &background); +} +#endif + +#ifdef PNG_READ_hIST_SUPPORTED +void /* PRIVATE */ +png_handle_hIST(png_structp png_ptr, png_infop info_ptr, png_uint_32 length) +{ + unsigned int num, i; + png_uint_16 readbuf[PNG_MAX_PALETTE_LENGTH]; + + png_debug(1, "in png_handle_hIST"); + + if (!(png_ptr->mode & PNG_HAVE_IHDR)) + png_error(png_ptr, "Missing IHDR before hIST"); + + else if (png_ptr->mode & PNG_HAVE_IDAT) + { + png_warning(png_ptr, "Invalid hIST after IDAT"); + png_crc_finish(png_ptr, length); + return; + } + + else if (!(png_ptr->mode & PNG_HAVE_PLTE)) + { + png_warning(png_ptr, "Missing PLTE before hIST"); + png_crc_finish(png_ptr, length); + return; + } + + else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST)) + { + png_warning(png_ptr, "Duplicate hIST chunk"); + png_crc_finish(png_ptr, length); + return; + } + + if (length > 2*PNG_MAX_PALETTE_LENGTH || + length != (unsigned int) (2*png_ptr->num_palette)) + { + png_warning(png_ptr, "Incorrect hIST chunk length"); + png_crc_finish(png_ptr, length); + return; + } + + num = length / 2 ; + + for (i = 0; i < num; i++) + { + png_byte buf[2]; + + png_crc_read(png_ptr, buf, 2); + readbuf[i] = png_get_uint_16(buf); + } + + if (png_crc_finish(png_ptr, 0)) + return; + + png_set_hIST(png_ptr, info_ptr, readbuf); +} +#endif + +#ifdef PNG_READ_pHYs_SUPPORTED +void /* PRIVATE */ +png_handle_pHYs(png_structp png_ptr, png_infop info_ptr, png_uint_32 length) +{ + png_byte buf[9]; + png_uint_32 res_x, res_y; + int unit_type; + + png_debug(1, "in png_handle_pHYs"); + + if (!(png_ptr->mode & PNG_HAVE_IHDR)) + png_error(png_ptr, "Missing IHDR before pHYs"); + + else if (png_ptr->mode & PNG_HAVE_IDAT) + { + png_warning(png_ptr, "Invalid pHYs after IDAT"); + png_crc_finish(png_ptr, length); + return; + } + + else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs)) + { + png_warning(png_ptr, "Duplicate pHYs chunk"); + png_crc_finish(png_ptr, length); + return; + } + + if (length != 9) + { + png_warning(png_ptr, "Incorrect pHYs chunk length"); + png_crc_finish(png_ptr, length); + return; + } + + png_crc_read(png_ptr, buf, 9); + + if (png_crc_finish(png_ptr, 0)) + return; + + res_x = png_get_uint_32(buf); + res_y = png_get_uint_32(buf + 4); + unit_type = buf[8]; + png_set_pHYs(png_ptr, info_ptr, res_x, res_y, unit_type); +} +#endif + +#ifdef PNG_READ_oFFs_SUPPORTED +void /* PRIVATE */ +png_handle_oFFs(png_structp png_ptr, png_infop info_ptr, png_uint_32 length) +{ + png_byte buf[9]; + png_int_32 offset_x, offset_y; + int unit_type; + + png_debug(1, "in png_handle_oFFs"); + + if (!(png_ptr->mode & PNG_HAVE_IHDR)) + png_error(png_ptr, "Missing IHDR before oFFs"); + + else if (png_ptr->mode & PNG_HAVE_IDAT) + { + png_warning(png_ptr, "Invalid oFFs after IDAT"); + png_crc_finish(png_ptr, length); + return; + } + + else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs)) + { + png_warning(png_ptr, "Duplicate oFFs chunk"); + png_crc_finish(png_ptr, length); + return; + } + + if (length != 9) + { + png_warning(png_ptr, "Incorrect oFFs chunk length"); + png_crc_finish(png_ptr, length); + return; + } + + png_crc_read(png_ptr, buf, 9); + + if (png_crc_finish(png_ptr, 0)) + return; + + offset_x = png_get_int_32(buf); + offset_y = png_get_int_32(buf + 4); + unit_type = buf[8]; + png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y, unit_type); +} +#endif + +#ifdef PNG_READ_pCAL_SUPPORTED +/* Read the pCAL chunk (described in the PNG Extensions document) */ +void /* PRIVATE */ +png_handle_pCAL(png_structp png_ptr, png_infop info_ptr, png_uint_32 length) +{ + png_int_32 X0, X1; + png_byte type, nparams; + png_charp buf, units, endptr; + png_charpp params; + png_size_t slength; + int i; + + png_debug(1, "in png_handle_pCAL"); + + if (!(png_ptr->mode & PNG_HAVE_IHDR)) + png_error(png_ptr, "Missing IHDR before pCAL"); + + else if (png_ptr->mode & PNG_HAVE_IDAT) + { + png_warning(png_ptr, "Invalid pCAL after IDAT"); + png_crc_finish(png_ptr, length); + return; + } + + else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL)) + { + png_warning(png_ptr, "Duplicate pCAL chunk"); + png_crc_finish(png_ptr, length); + return; + } + + png_debug1(2, "Allocating and reading pCAL chunk data (%u bytes)", + length + 1); + png_free(png_ptr, png_ptr->chunkdata); + png_ptr->chunkdata = (png_charp)png_malloc_warn(png_ptr, length + 1); + + if (png_ptr->chunkdata == NULL) + { + png_warning(png_ptr, "No memory for pCAL purpose"); + return; + } + + slength = length; + png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength); + + if (png_crc_finish(png_ptr, 0)) + { + png_free(png_ptr, png_ptr->chunkdata); + png_ptr->chunkdata = NULL; + return; + } + + png_ptr->chunkdata[slength] = 0x00; /* Null terminate the last string */ + + png_debug(3, "Finding end of pCAL purpose string"); + for (buf = png_ptr->chunkdata; *buf; buf++) + /* Empty loop */ ; + + endptr = png_ptr->chunkdata + slength; + + /* We need to have at least 12 bytes after the purpose string + * in order to get the parameter information. + */ + if (endptr <= buf + 12) + { + png_warning(png_ptr, "Invalid pCAL data"); + png_free(png_ptr, png_ptr->chunkdata); + png_ptr->chunkdata = NULL; + return; + } + + png_debug(3, "Reading pCAL X0, X1, type, nparams, and units"); + X0 = png_get_int_32((png_bytep)buf+1); + X1 = png_get_int_32((png_bytep)buf+5); + type = buf[9]; + nparams = buf[10]; + units = buf + 11; + + png_debug(3, "Checking pCAL equation type and number of parameters"); + /* Check that we have the right number of parameters for known + * equation types. + */ + if ((type == PNG_EQUATION_LINEAR && nparams != 2) || + (type == PNG_EQUATION_BASE_E && nparams != 3) || + (type == PNG_EQUATION_ARBITRARY && nparams != 3) || + (type == PNG_EQUATION_HYPERBOLIC && nparams != 4)) + { + png_warning(png_ptr, "Invalid pCAL parameters for equation type"); + png_free(png_ptr, png_ptr->chunkdata); + png_ptr->chunkdata = NULL; + return; + } + + else if (type >= PNG_EQUATION_LAST) + { + png_warning(png_ptr, "Unrecognized equation type for pCAL chunk"); + } + + for (buf = units; *buf; buf++) + /* Empty loop to move past the units string. */ ; + + png_debug(3, "Allocating pCAL parameters array"); + + params = (png_charpp)png_malloc_warn(png_ptr, + (png_size_t)(nparams * png_sizeof(png_charp))); + + if (params == NULL) + { + png_free(png_ptr, png_ptr->chunkdata); + png_ptr->chunkdata = NULL; + png_warning(png_ptr, "No memory for pCAL params"); + return; + } + + /* Get pointers to the start of each parameter string. */ + for (i = 0; i < (int)nparams; i++) + { + buf++; /* Skip the null string terminator from previous parameter. */ + + png_debug1(3, "Reading pCAL parameter %d", i); + + for (params[i] = buf; buf <= endptr && *buf != 0x00; buf++) + /* Empty loop to move past each parameter string */ ; + + /* Make sure we haven't run out of data yet */ + if (buf > endptr) + { + png_warning(png_ptr, "Invalid pCAL data"); + png_free(png_ptr, png_ptr->chunkdata); + png_ptr->chunkdata = NULL; + png_free(png_ptr, params); + return; + } + } + + png_set_pCAL(png_ptr, info_ptr, png_ptr->chunkdata, X0, X1, type, nparams, + units, params); + + png_free(png_ptr, png_ptr->chunkdata); + png_ptr->chunkdata = NULL; + png_free(png_ptr, params); +} +#endif + +#ifdef PNG_READ_sCAL_SUPPORTED +/* Read the sCAL chunk */ +void /* PRIVATE */ +png_handle_sCAL(png_structp png_ptr, png_infop info_ptr, png_uint_32 length) +{ + png_size_t slength, i; + int state; + + png_debug(1, "in png_handle_sCAL"); + + if (!(png_ptr->mode & PNG_HAVE_IHDR)) + png_error(png_ptr, "Missing IHDR before sCAL"); + + else if (png_ptr->mode & PNG_HAVE_IDAT) + { + png_warning(png_ptr, "Invalid sCAL after IDAT"); + png_crc_finish(png_ptr, length); + return; + } + + else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sCAL)) + { + png_warning(png_ptr, "Duplicate sCAL chunk"); + png_crc_finish(png_ptr, length); + return; + } + + /* Need unit type, width, \0, height: minimum 4 bytes */ + else if (length < 4) + { + png_warning(png_ptr, "sCAL chunk too short"); + png_crc_finish(png_ptr, length); + return; + } + + png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)", + length + 1); + + png_ptr->chunkdata = (png_charp)png_malloc_warn(png_ptr, length + 1); + + if (png_ptr->chunkdata == NULL) + { + png_warning(png_ptr, "Out of memory while processing sCAL chunk"); + png_crc_finish(png_ptr, length); + return; + } + + slength = length; + png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength); + png_ptr->chunkdata[slength] = 0x00; /* Null terminate the last string */ + + if (png_crc_finish(png_ptr, 0)) + { + png_free(png_ptr, png_ptr->chunkdata); + png_ptr->chunkdata = NULL; + return; + } + + /* Validate the unit. */ + if (png_ptr->chunkdata[0] != 1 && png_ptr->chunkdata[0] != 2) + { + png_warning(png_ptr, "Invalid sCAL ignored: invalid unit"); + png_free(png_ptr, png_ptr->chunkdata); + png_ptr->chunkdata = NULL; + return; + } + + /* Validate the ASCII numbers, need two ASCII numbers separated by + * a '\0' and they need to fit exactly in the chunk data. + */ + i = 1; + state = 0; + + if (!png_check_fp_number(png_ptr->chunkdata, slength, &state, &i) || + i >= slength || png_ptr->chunkdata[i++] != 0) + png_warning(png_ptr, "Invalid sCAL chunk ignored: bad width format"); + + else if (!PNG_FP_IS_POSITIVE(state)) + png_warning(png_ptr, "Invalid sCAL chunk ignored: non-positive width"); + + else + { + png_size_t heighti = i; + + state = 0; + if (!png_check_fp_number(png_ptr->chunkdata, slength, &state, &i) || + i != slength) + png_warning(png_ptr, "Invalid sCAL chunk ignored: bad height format"); + + else if (!PNG_FP_IS_POSITIVE(state)) + png_warning(png_ptr, + "Invalid sCAL chunk ignored: non-positive height"); + + else + /* This is the (only) success case. */ + png_set_sCAL_s(png_ptr, info_ptr, png_ptr->chunkdata[0], + png_ptr->chunkdata+1, png_ptr->chunkdata+heighti); + } + + /* Clean up - just free the temporarily allocated buffer. */ + png_free(png_ptr, png_ptr->chunkdata); + png_ptr->chunkdata = NULL; +} +#endif + +#ifdef PNG_READ_tIME_SUPPORTED +void /* PRIVATE */ +png_handle_tIME(png_structp png_ptr, png_infop info_ptr, png_uint_32 length) +{ + png_byte buf[7]; + png_time mod_time; + + png_debug(1, "in png_handle_tIME"); + + if (!(png_ptr->mode & PNG_HAVE_IHDR)) + png_error(png_ptr, "Out of place tIME chunk"); + + else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME)) + { + png_warning(png_ptr, "Duplicate tIME chunk"); + png_crc_finish(png_ptr, length); + return; + } + + if (png_ptr->mode & PNG_HAVE_IDAT) + png_ptr->mode |= PNG_AFTER_IDAT; + + if (length != 7) + { + png_warning(png_ptr, "Incorrect tIME chunk length"); + png_crc_finish(png_ptr, length); + return; + } + + png_crc_read(png_ptr, buf, 7); + + if (png_crc_finish(png_ptr, 0)) + return; + + mod_time.second = buf[6]; + mod_time.minute = buf[5]; + mod_time.hour = buf[4]; + mod_time.day = buf[3]; + mod_time.month = buf[2]; + mod_time.year = png_get_uint_16(buf); + + png_set_tIME(png_ptr, info_ptr, &mod_time); +} +#endif + +#ifdef PNG_READ_tEXt_SUPPORTED +/* Note: this does not properly handle chunks that are > 64K under DOS */ +void /* PRIVATE */ +png_handle_tEXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length) +{ + png_textp text_ptr; + png_charp key; + png_charp text; + png_uint_32 skip = 0; + png_size_t slength; + int ret; + + png_debug(1, "in png_handle_tEXt"); + +#ifdef PNG_USER_LIMITS_SUPPORTED + if (png_ptr->user_chunk_cache_max != 0) + { + if (png_ptr->user_chunk_cache_max == 1) + { + png_crc_finish(png_ptr, length); + return; + } + + if (--png_ptr->user_chunk_cache_max == 1) + { + png_warning(png_ptr, "No space in chunk cache for tEXt"); + png_crc_finish(png_ptr, length); + return; + } + } +#endif + + if (!(png_ptr->mode & PNG_HAVE_IHDR)) + png_error(png_ptr, "Missing IHDR before tEXt"); + + if (png_ptr->mode & PNG_HAVE_IDAT) + png_ptr->mode |= PNG_AFTER_IDAT; + +#ifdef PNG_MAX_MALLOC_64K + if (length > (png_uint_32)65535L) + { + png_warning(png_ptr, "tEXt chunk too large to fit in memory"); + skip = length - (png_uint_32)65535L; + length = (png_uint_32)65535L; + } +#endif + + png_free(png_ptr, png_ptr->chunkdata); + + png_ptr->chunkdata = (png_charp)png_malloc_warn(png_ptr, length + 1); + + if (png_ptr->chunkdata == NULL) + { + png_warning(png_ptr, "No memory to process text chunk"); + return; + } + + slength = length; + png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength); + + if (png_crc_finish(png_ptr, skip)) + { + png_free(png_ptr, png_ptr->chunkdata); + png_ptr->chunkdata = NULL; + return; + } + + key = png_ptr->chunkdata; + + key[slength] = 0x00; + + for (text = key; *text; text++) + /* Empty loop to find end of key */ ; + + if (text != key + slength) + text++; + + text_ptr = (png_textp)png_malloc_warn(png_ptr, + png_sizeof(png_text)); + + if (text_ptr == NULL) + { + png_warning(png_ptr, "Not enough memory to process text chunk"); + png_free(png_ptr, png_ptr->chunkdata); + png_ptr->chunkdata = NULL; + return; + } + + text_ptr->compression = PNG_TEXT_COMPRESSION_NONE; + text_ptr->key = key; + text_ptr->lang = NULL; + text_ptr->lang_key = NULL; + text_ptr->itxt_length = 0; + text_ptr->text = text; + text_ptr->text_length = png_strlen(text); + + ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1); + + png_free(png_ptr, png_ptr->chunkdata); + png_ptr->chunkdata = NULL; + png_free(png_ptr, text_ptr); + + if (ret) + png_warning(png_ptr, "Insufficient memory to process text chunk"); +} +#endif + +#ifdef PNG_READ_zTXt_SUPPORTED +/* Note: this does not correctly handle chunks that are > 64K under DOS */ +void /* PRIVATE */ +png_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length) +{ + png_textp text_ptr; + png_charp text; + int comp_type; + int ret; + png_size_t slength, prefix_len, data_len; + + png_debug(1, "in png_handle_zTXt"); + +#ifdef PNG_USER_LIMITS_SUPPORTED + if (png_ptr->user_chunk_cache_max != 0) + { + if (png_ptr->user_chunk_cache_max == 1) + { + png_crc_finish(png_ptr, length); + return; + } + + if (--png_ptr->user_chunk_cache_max == 1) + { + png_warning(png_ptr, "No space in chunk cache for zTXt"); + png_crc_finish(png_ptr, length); + return; + } + } +#endif + + if (!(png_ptr->mode & PNG_HAVE_IHDR)) + png_error(png_ptr, "Missing IHDR before zTXt"); + + if (png_ptr->mode & PNG_HAVE_IDAT) + png_ptr->mode |= PNG_AFTER_IDAT; + +#ifdef PNG_MAX_MALLOC_64K + /* We will no doubt have problems with chunks even half this size, but + * there is no hard and fast rule to tell us where to stop. + */ + if (length > (png_uint_32)65535L) + { + png_warning(png_ptr, "zTXt chunk too large to fit in memory"); + png_crc_finish(png_ptr, length); + return; + } +#endif + + png_free(png_ptr, png_ptr->chunkdata); + png_ptr->chunkdata = (png_charp)png_malloc_warn(png_ptr, length + 1); + + if (png_ptr->chunkdata == NULL) + { + png_warning(png_ptr, "Out of memory processing zTXt chunk"); + return; + } + + slength = length; + png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength); + + if (png_crc_finish(png_ptr, 0)) + { + png_free(png_ptr, png_ptr->chunkdata); + png_ptr->chunkdata = NULL; + return; + } + + png_ptr->chunkdata[slength] = 0x00; + + for (text = png_ptr->chunkdata; *text; text++) + /* Empty loop */ ; + + /* zTXt must have some text after the chunkdataword */ + if (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 = 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++; + } + + if (comp_type || (comp_flag && comp_flag != PNG_TEXT_COMPRESSION_zTXt)) + { + png_warning(png_ptr, "Unknown iTXt compression type or method"); + png_free(png_ptr, png_ptr->chunkdata); + png_ptr->chunkdata = NULL; + return; + } + + for (lang_key = lang; *lang_key; lang_key++) + /* Empty loop */ ; + + lang_key++; /* Skip NUL separator */ + + if (lang_key >= png_ptr->chunkdata + slength) + { + png_warning(png_ptr, "Truncated iTXt chunk"); + png_free(png_ptr, png_ptr->chunkdata); + png_ptr->chunkdata = NULL; + return; + } + + for (text = lang_key; *text; text++) + /* Empty loop */ ; + + text++; /* Skip NUL separator */ + + if (text >= png_ptr->chunkdata + slength) + { + png_warning(png_ptr, "Malformed iTXt chunk"); + png_free(png_ptr, png_ptr->chunkdata); + png_ptr->chunkdata = NULL; + return; + } + + prefix_len = text - png_ptr->chunkdata; + + key=png_ptr->chunkdata; + + if (comp_flag) + 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 'display' value; if 'display' is true then the whole row + * (dp) is filled from the start by replicating the available pixels. If + * 'display' is false only those pixels present in the pass are filled in. + */ +void /* PRIVATE */ +png_combine_row(png_structp png_ptr, png_bytep dp, int display) +{ + unsigned int pixel_depth = png_ptr->transformed_pixel_depth; + png_const_bytep sp = png_ptr->row_buf + 1; + png_uint_32 row_width = png_ptr->width; + unsigned int pass = png_ptr->pass; + png_bytep end_ptr = 0; + png_byte end_byte = 0; + unsigned int end_mask; + + png_debug(1, "in png_combine_row"); + + /* Added in 1.5.6: it should not be possible to enter this routine until at + * least one row has been read from the PNG data and transformed. + */ + if (pixel_depth == 0) + png_error(png_ptr, "internal row logic error"); + + /* Added in 1.5.4: the pixel depth should match the information returned by + * any call to png_read_update_info at this point. Do not continue if we got + * this wrong. + */ + if (png_ptr->info_rowbytes != 0 && png_ptr->info_rowbytes != + PNG_ROWBYTES(pixel_depth, row_width)) + png_error(png_ptr, "internal row size calculation error"); + + /* Don't expect this to ever happen: */ + if (row_width == 0) + png_error(png_ptr, "internal row width error"); + + /* Preserve the last byte in cases where only part of it will be overwritten, + * the multiply below may overflow, we don't care because ANSI-C guarantees + * we get the low bits. + */ + end_mask = (pixel_depth * row_width) & 7; + if (end_mask != 0) + { + /* end_ptr == NULL is a flag to say do nothing */ + end_ptr = dp + PNG_ROWBYTES(pixel_depth, row_width) - 1; + end_byte = *end_ptr; +# ifdef PNG_READ_PACKSWAP_SUPPORTED + if (png_ptr->transformations & PNG_PACKSWAP) /* little-endian byte */ + end_mask = 0xff << end_mask; + + else /* big-endian byte */ +# endif + end_mask = 0xff >> end_mask; + /* end_mask is now the bits to *keep* from the destination row */ + } + + /* For non-interlaced images this reduces to a png_memcpy(). A png_memcpy() + * will also happen if interlacing isn't supported or if the application + * does not call png_set_interlace_handling(). In the latter cases the + * caller just gets a sequence of the unexpanded rows from each interlace + * pass. + */ +#ifdef PNG_READ_INTERLACING_SUPPORTED + if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE) && + pass < 6 && (display == 0 || + /* The following copies everything for 'display' on passes 0, 2 and 4. */ + (display == 1 && (pass & 1) != 0))) + { + /* Narrow images may have no bits in a pass; the caller should handle + * this, but this test is cheap: + */ + if (row_width <= PNG_PASS_START_COL(pass)) + return; + + if (pixel_depth < 8) + { + /* For pixel depths up to 4 bpp the 8-pixel mask can be expanded to fit + * into 32 bits, then a single loop over the bytes using the four byte + * values in the 32-bit mask can be used. For the 'display' option the + * expanded mask may also not require any masking within a byte. To + * make this work the PACKSWAP option must be taken into account - it + * simply requires the pixels to be reversed in each byte. + * + * The 'regular' case requires a mask for each of the first 6 passes, + * the 'display' case does a copy for the even passes in the range + * 0..6. This has already been handled in the test above. + * + * The masks are arranged as four bytes with the first byte to use in + * the lowest bits (little-endian) regardless of the order (PACKSWAP or + * not) of the pixels in each byte. + * + * NOTE: the whole of this logic depends on the caller of this function + * only calling it on rows appropriate to the pass. This function only + * understands the 'x' logic; the 'y' logic is handled by the caller. + * + * The following defines allow generation of compile time constant bit + * masks for each pixel depth and each possibility of swapped or not + * swapped bytes. Pass 'p' is in the range 0..6; 'x', a pixel index, + * is in the range 0..7; and the result is 1 if the pixel is to be + * copied in the pass, 0 if not. 'S' is for the sparkle method, 'B' + * for the block method. + * + * With some compilers a compile time expression of the general form: + * + * (shift >= 32) ? (a >> (shift-32)) : (b >> shift) + * + * Produces warnings with values of 'shift' in the range 33 to 63 + * because the right hand side of the ?: expression is evaluated by + * the compiler even though it isn't used. Microsoft Visual C (various + * versions) and the Intel C compiler are known to do this. To avoid + * this the following macros are used in 1.5.6. This is a temporary + * solution to avoid destabilizing the code during the release process. + */ +# if PNG_USE_COMPILE_TIME_MASKS +# define PNG_LSR(x,s) ((x)>>((s) & 0x1f)) +# define PNG_LSL(x,s) ((x)<<((s) & 0x1f)) +# else +# define PNG_LSR(x,s) ((x)>>(s)) +# define PNG_LSL(x,s) ((x)<<(s)) +# endif +# define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\ + PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1) +# define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\ + PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1) + + /* Return a mask for pass 'p' pixel 'x' at depth 'd'. The mask is + * little endian - the first pixel is at bit 0 - however the extra + * parameter 's' can be set to cause the mask position to be swapped + * within each byte, to match the PNG format. This is done by XOR of + * the shift with 7, 6 or 4 for bit depths 1, 2 and 4. + */ +# define PIXEL_MASK(p,x,d,s) \ + (PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0)))) + + /* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask. + */ +# define S_MASKx(p,x,d,s) (S_COPY(p,x)?PIXEL_MASK(p,x,d,s):0) +# define B_MASKx(p,x,d,s) (B_COPY(p,x)?PIXEL_MASK(p,x,d,s):0) + + /* Combine 8 of these to get the full mask. For the 1-bpp and 2-bpp + * cases the result needs replicating, for the 4-bpp case the above + * generates a full 32 bits. + */ +# define MASK_EXPAND(m,d) ((m)*((d)==1?0x01010101:((d)==2?0x00010001:1))) + +# define S_MASK(p,d,s) MASK_EXPAND(S_MASKx(p,0,d,s) + S_MASKx(p,1,d,s) +\ + S_MASKx(p,2,d,s) + S_MASKx(p,3,d,s) + S_MASKx(p,4,d,s) +\ + S_MASKx(p,5,d,s) + S_MASKx(p,6,d,s) + S_MASKx(p,7,d,s), d) + +# define B_MASK(p,d,s) MASK_EXPAND(B_MASKx(p,0,d,s) + B_MASKx(p,1,d,s) +\ + B_MASKx(p,2,d,s) + B_MASKx(p,3,d,s) + B_MASKx(p,4,d,s) +\ + B_MASKx(p,5,d,s) + B_MASKx(p,6,d,s) + B_MASKx(p,7,d,s), d) + +#if PNG_USE_COMPILE_TIME_MASKS + /* Utility macros to construct all the masks for a depth/swap + * combination. The 's' parameter says whether the format is PNG + * (big endian bytes) or not. Only the three odd-numbered passes are + * required for the display/block algorithm. + */ +# define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\ + S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) } + +# define B_MASKS(d,s) { B_MASK(1,d,s), S_MASK(3,d,s), S_MASK(5,d,s) } + +# define DEPTH_INDEX(d) ((d)==1?0:((d)==2?1:2)) + + /* Hence the pre-compiled masks indexed by PACKSWAP (or not), depth and + * then pass: + */ + static PNG_CONST png_uint_32 row_mask[2/*PACKSWAP*/][3/*depth*/][6] = + { + /* Little-endian byte masks for PACKSWAP */ + { S_MASKS(1,0), S_MASKS(2,0), S_MASKS(4,0) }, + /* Normal (big-endian byte) masks - PNG format */ + { S_MASKS(1,1), S_MASKS(2,1), S_MASKS(4,1) } + }; + + /* display_mask has only three entries for the odd passes, so index by + * pass>>1. + */ + static PNG_CONST png_uint_32 display_mask[2][3][3] = + { + /* Little-endian byte masks for PACKSWAP */ + { B_MASKS(1,0), B_MASKS(2,0), B_MASKS(4,0) }, + /* Normal (big-endian byte) masks - PNG format */ + { B_MASKS(1,1), B_MASKS(2,1), B_MASKS(4,1) } + }; + +# define MASK(pass,depth,display,png)\ + ((display)?display_mask[png][DEPTH_INDEX(depth)][pass>>1]:\ + row_mask[png][DEPTH_INDEX(depth)][pass]) + +#else /* !PNG_USE_COMPILE_TIME_MASKS */ + /* This is the runtime alternative: it seems unlikely that this will + * ever be either smaller or faster than the compile time approach. + */ +# define MASK(pass,depth,display,png)\ + ((display)?B_MASK(pass,depth,png):S_MASK(pass,depth,png)) +#endif /* !PNG_USE_COMPILE_TIME_MASKS */ + + /* Use the appropriate mask to copy the required bits. In some cases + * the byte mask will be 0 or 0xff, optimize these cases. row_width is + * the number of pixels, but the code copies bytes, so it is necessary + * to special case the end. + */ + png_uint_32 pixels_per_byte = 8 / pixel_depth; + png_uint_32 mask; + +# ifdef PNG_READ_PACKSWAP_SUPPORTED + if (png_ptr->transformations & PNG_PACKSWAP) + mask = MASK(pass, pixel_depth, display, 0); + + else +# endif + mask = MASK(pass, pixel_depth, display, 1); + + for (;;) + { + png_uint_32 m; + + /* It doesn't matter in the following if png_uint_32 has more than + * 32 bits because the high bits always match those in m<<24; it is, + * however, essential to use OR here, not +, because of this. + */ + m = mask; + mask = (m >> 8) | (m << 24); /* rotate right to good compilers */ + m &= 0xff; + + if (m != 0) /* something to copy */ + { + if (m != 0xff) + *dp = (png_byte)((*dp & ~m) | (*sp & m)); + else + *dp = *sp; + } + + /* NOTE: this may overwrite the last byte with garbage if the image + * is not an exact number of bytes wide; libpng has always done + * this. + */ + if (row_width <= pixels_per_byte) + break; /* May need to restore part of the last byte */ + + row_width -= pixels_per_byte; + ++dp; + ++sp; + } + } + + else /* pixel_depth >= 8 */ + { + unsigned int bytes_to_copy, bytes_to_jump; + + /* Validate the depth - it must be a multiple of 8 */ + if (pixel_depth & 7) + png_error(png_ptr, "invalid user transform pixel depth"); + + pixel_depth >>= 3; /* now in bytes */ + row_width *= pixel_depth; + + /* Regardless of pass number the Adam 7 interlace always results in a + * fixed number of pixels to copy then to skip. There may be a + * different number of pixels to skip at the start though. + */ + { + unsigned int offset = PNG_PASS_START_COL(pass) * pixel_depth; + + row_width -= offset; + dp += offset; + sp += offset; + } + + /* Work out the bytes to copy. */ + if (display) + { + /* When doing the 'block' algorithm the pixel in the pass gets + * replicated to adjacent pixels. This is why the even (0,2,4,6) + * passes are skipped above - the entire expanded row is copied. + */ + bytes_to_copy = (1<<((6-pass)>>1)) * pixel_depth; + + /* But don't allow this number to exceed the actual row width. */ + if (bytes_to_copy > row_width) + bytes_to_copy = row_width; + } + + else /* normal row; Adam7 only ever gives us one pixel to copy. */ + bytes_to_copy = pixel_depth; + + /* In Adam7 there is a constant offset between where the pixels go. */ + bytes_to_jump = PNG_PASS_COL_OFFSET(pass) * pixel_depth; + + /* And simply copy these bytes. Some optimization is possible here, + * depending on the value of 'bytes_to_copy'. Special case the low + * byte counts, which we know to be frequent. + * + * Notice that these cases all 'return' rather than 'break' - this + * avoids an unnecessary test on whether to restore the last byte + * below. + */ + switch (bytes_to_copy) + { + case 1: + for (;;) + { + *dp = *sp; + + if (row_width <= bytes_to_jump) + return; + + dp += bytes_to_jump; + sp += bytes_to_jump; + row_width -= bytes_to_jump; + } + + case 2: + /* There is a possibility of a partial copy at the end here; this + * slows the code down somewhat. + */ + do + { + dp[0] = sp[0], dp[1] = sp[1]; + + if (row_width <= bytes_to_jump) + return; + + sp += bytes_to_jump; + dp += bytes_to_jump; + row_width -= bytes_to_jump; + } + while (row_width > 1); + + /* And there can only be one byte left at this point: */ + *dp = *sp; + return; + + case 3: + /* This can only be the RGB case, so each copy is exactly one + * pixel and it is not necessary to check for a partial copy. + */ + for(;;) + { + dp[0] = sp[0], dp[1] = sp[1], dp[2] = sp[2]; + + if (row_width <= bytes_to_jump) + return; + + sp += bytes_to_jump; + dp += bytes_to_jump; + row_width -= bytes_to_jump; + } + + default: +#if PNG_ALIGN_TYPE != PNG_ALIGN_NONE + /* Check for double byte alignment and, if possible, use a + * 16-bit copy. Don't attempt this for narrow images - ones that + * are less than an interlace panel wide. Don't attempt it for + * wide bytes_to_copy either - use the png_memcpy there. + */ + if (bytes_to_copy < 16 /*else use png_memcpy*/ && + png_isaligned(dp, png_uint_16) && + png_isaligned(sp, png_uint_16) && + bytes_to_copy % sizeof (png_uint_16) == 0 && + bytes_to_jump % sizeof (png_uint_16) == 0) + { + /* Everything is aligned for png_uint_16 copies, but try for + * png_uint_32 first. + */ + if (png_isaligned(dp, png_uint_32) && + png_isaligned(sp, png_uint_32) && + bytes_to_copy % sizeof (png_uint_32) == 0 && + bytes_to_jump % sizeof (png_uint_32) == 0) + { + png_uint_32p dp32 = (png_uint_32p)dp; + png_const_uint_32p sp32 = (png_const_uint_32p)sp; + unsigned int skip = (bytes_to_jump-bytes_to_copy) / + sizeof (png_uint_32); + + do + { + size_t c = bytes_to_copy; + do + { + *dp32++ = *sp32++; + c -= sizeof (png_uint_32); + } + while (c > 0); + + if (row_width <= bytes_to_jump) + return; + + dp32 += skip; + sp32 += skip; + row_width -= bytes_to_jump; + } + while (bytes_to_copy <= row_width); + + /* Get to here when the row_width truncates the final copy. + * There will be 1-3 bytes left to copy, so don't try the + * 16-bit loop below. + */ + dp = (png_bytep)dp32; + sp = (png_const_bytep)sp32; + do + *dp++ = *sp++; + while (--row_width > 0); + return; + } + + /* Else do it in 16-bit quantities, but only if the size is + * not too large. + */ + else + { + png_uint_16p dp16 = (png_uint_16p)dp; + png_const_uint_16p sp16 = (png_const_uint_16p)sp; + unsigned int skip = (bytes_to_jump-bytes_to_copy) / + sizeof (png_uint_16); + + do + { + size_t c = bytes_to_copy; + do + { + *dp16++ = *sp16++; + c -= sizeof (png_uint_16); + } + while (c > 0); + + if (row_width <= bytes_to_jump) + return; + + dp16 += skip; + sp16 += skip; + row_width -= bytes_to_jump; + } + while (bytes_to_copy <= row_width); + + /* End of row - 1 byte left, bytes_to_copy > row_width: */ + dp = (png_bytep)dp16; + sp = (png_const_bytep)sp16; + do + *dp++ = *sp++; + while (--row_width > 0); + return; + } + } +#endif /* PNG_ALIGN_ code */ + + /* The true default - use a png_memcpy: */ + for (;;) + { + png_memcpy(dp, sp, bytes_to_copy); + + if (row_width <= bytes_to_jump) + return; + + sp += bytes_to_jump; + dp += bytes_to_jump; + row_width -= bytes_to_jump; + if (bytes_to_copy > row_width) + bytes_to_copy = row_width; + } + } + + /* NOT REACHED*/ + } /* pixel_depth >= 8 */ + + /* Here if pixel_depth < 8 to check 'end_ptr' below. */ + } + else +#endif + + /* If here then the switch above wasn't used so just png_memcpy the whole row + * from the temporary row buffer (notice that this overwrites the end of the + * destination row if it is a partial byte.) + */ + png_memcpy(dp, sp, PNG_ROWBYTES(pixel_depth, row_width)); + + /* Restore the overwritten bits from the last byte if necessary. */ + if (end_ptr != NULL) + *end_ptr = (png_byte)((end_byte & end_mask) | (*end_ptr & ~end_mask)); +} + +#ifdef PNG_READ_INTERLACING_SUPPORTED +void /* PRIVATE */ +png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass, + png_uint_32 transformations /* Because these may affect the byte layout */) +{ + /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ + /* Offset to next interlace block */ + static PNG_CONST int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; + + png_debug(1, "in png_do_read_interlace"); + if (row != NULL && row_info != NULL) + { + png_uint_32 final_width; + + final_width = row_info->width * png_pass_inc[pass]; + + switch (row_info->pixel_depth) + { + case 1: + { + png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 3); + png_bytep dp = row + (png_size_t)((final_width - 1) >> 3); + int sshift, dshift; + int s_start, s_end, s_inc; + int jstop = png_pass_inc[pass]; + png_byte v; + png_uint_32 i; + int j; + +#ifdef PNG_READ_PACKSWAP_SUPPORTED + if (transformations & PNG_PACKSWAP) + { + sshift = (int)((row_info->width + 7) & 0x07); + dshift = (int)((final_width + 7) & 0x07); + s_start = 7; + s_end = 0; + s_inc = -1; + } + + else +#endif + { + sshift = 7 - (int)((row_info->width + 7) & 0x07); + dshift = 7 - (int)((final_width + 7) & 0x07); + s_start = 0; + s_end = 7; + s_inc = 1; + } + + for (i = 0; i < row_info->width; i++) + { + v = (png_byte)((*sp >> sshift) & 0x01); + for (j = 0; j < jstop; j++) + { + *dp &= (png_byte)((0x7f7f >> (7 - dshift)) & 0xff); + *dp |= (png_byte)(v << dshift); + + if (dshift == s_end) + { + dshift = s_start; + dp--; + } + + else + dshift += s_inc; + } + + if (sshift == s_end) + { + sshift = s_start; + sp--; + } + + else + sshift += s_inc; + } + break; + } + + case 2: + { + png_bytep sp = row + (png_uint_32)((row_info->width - 1) >> 2); + png_bytep dp = row + (png_uint_32)((final_width - 1) >> 2); + int sshift, dshift; + int s_start, s_end, s_inc; + int jstop = png_pass_inc[pass]; + png_uint_32 i; + +#ifdef PNG_READ_PACKSWAP_SUPPORTED + if (transformations & PNG_PACKSWAP) + { + sshift = (int)(((row_info->width + 3) & 0x03) << 1); + dshift = (int)(((final_width + 3) & 0x03) << 1); + s_start = 6; + s_end = 0; + s_inc = -2; + } + + else +#endif + { + sshift = (int)((3 - ((row_info->width + 3) & 0x03)) << 1); + dshift = (int)((3 - ((final_width + 3) & 0x03)) << 1); + s_start = 0; + s_end = 6; + s_inc = 2; + } + + for (i = 0; i < row_info->width; i++) + { + png_byte v; + int j; + + v = (png_byte)((*sp >> sshift) & 0x03); + for (j = 0; j < jstop; j++) + { + *dp &= (png_byte)((0x3f3f >> (6 - dshift)) & 0xff); + *dp |= (png_byte)(v << dshift); + + if (dshift == s_end) + { + dshift = s_start; + dp--; + } + + else + dshift += s_inc; + } + + if (sshift == s_end) + { + sshift = s_start; + sp--; + } + + else + sshift += s_inc; + } + break; + } + + case 4: + { + png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 1); + png_bytep dp = row + (png_size_t)((final_width - 1) >> 1); + int sshift, dshift; + int s_start, s_end, s_inc; + png_uint_32 i; + int jstop = png_pass_inc[pass]; + +#ifdef PNG_READ_PACKSWAP_SUPPORTED + if (transformations & PNG_PACKSWAP) + { + sshift = (int)(((row_info->width + 1) & 0x01) << 2); + dshift = (int)(((final_width + 1) & 0x01) << 2); + s_start = 4; + s_end = 0; + s_inc = -4; + } + + else +#endif + { + sshift = (int)((1 - ((row_info->width + 1) & 0x01)) << 2); + dshift = (int)((1 - ((final_width + 1) & 0x01)) << 2); + s_start = 0; + s_end = 4; + s_inc = 4; + } + + for (i = 0; i < row_info->width; i++) + { + png_byte v = (png_byte)((*sp >> sshift) & 0x0f); + int j; + + for (j = 0; j < jstop; j++) + { + *dp &= (png_byte)((0xf0f >> (4 - dshift)) & 0xff); + *dp |= (png_byte)(v << dshift); + + if (dshift == s_end) + { + dshift = s_start; + dp--; + } + + else + dshift += s_inc; + } + + if (sshift == s_end) + { + sshift = s_start; + sp--; + } + + else + sshift += s_inc; + } + break; + } + + default: + { + png_size_t pixel_bytes = (row_info->pixel_depth >> 3); + + png_bytep sp = row + (png_size_t)(row_info->width - 1) + * pixel_bytes; + + png_bytep dp = row + (png_size_t)(final_width - 1) * pixel_bytes; + + int jstop = png_pass_inc[pass]; + png_uint_32 i; + + for (i = 0; i < row_info->width; i++) + { + png_byte v[8]; + int j; + + png_memcpy(v, sp, pixel_bytes); + + for (j = 0; j < jstop; j++) + { + png_memcpy(dp, v, pixel_bytes); + dp -= pixel_bytes; + } + + sp -= pixel_bytes; + } + break; + } + } + + row_info->width = final_width; + row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, final_width); + } +#ifndef PNG_READ_PACKSWAP_SUPPORTED + PNG_UNUSED(transformations) /* Silence compiler warning */ +#endif +} +#endif /* PNG_READ_INTERLACING_SUPPORTED */ + +static void +png_read_filter_row_sub(png_row_infop row_info, png_bytep row, + png_const_bytep prev_row) +{ + png_size_t i; + png_size_t istop = row_info->rowbytes; + unsigned int bpp = (row_info->pixel_depth + 7) >> 3; + png_bytep rp = row + bpp; + + PNG_UNUSED(prev_row) + + for (i = bpp; i < istop; i++) + { + *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff); + rp++; + } +} + +static void +png_read_filter_row_up(png_row_infop row_info, png_bytep row, + png_const_bytep prev_row) +{ + png_size_t i; + png_size_t istop = row_info->rowbytes; + png_bytep rp = row; + png_const_bytep pp = prev_row; + + for (i = 0; i < istop; i++) + { + *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff); + rp++; + } +} + +static void +png_read_filter_row_avg(png_row_infop row_info, png_bytep row, + png_const_bytep prev_row) +{ + png_size_t i; + png_bytep rp = row; + png_const_bytep pp = prev_row; + unsigned int bpp = (row_info->pixel_depth + 7) >> 3; + png_size_t istop = row_info->rowbytes - bpp; + + for (i = 0; i < bpp; i++) + { + *rp = (png_byte)(((int)(*rp) + + ((int)(*pp++) / 2 )) & 0xff); + + rp++; + } + + for (i = 0; i < istop; i++) + { + *rp = (png_byte)(((int)(*rp) + + (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff); + + rp++; + } +} + +static void +png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info, png_bytep row, + png_const_bytep prev_row) +{ + png_bytep rp_end = row + row_info->rowbytes; + int a, c; + + /* First pixel/byte */ + c = *prev_row++; + a = *row + c; + *row++ = (png_byte)a; + + /* Remainder */ + while (row < rp_end) + { + int b, pa, pb, pc, p; + + a &= 0xff; /* From previous iteration or start */ + b = *prev_row++; + + p = b - c; + pc = a - c; + +# ifdef PNG_USE_ABS + pa = abs(p); + pb = abs(pc); + pc = abs(p + pc); +# else + pa = p < 0 ? -p : p; + pb = pc < 0 ? -pc : pc; + pc = (p + pc) < 0 ? -(p + pc) : p + pc; +# endif + + /* Find the best predictor, the least of pa, pb, pc favoring the earlier + * ones in the case of a tie. + */ + if (pb < pa) pa = pb, a = b; + if (pc < pa) a = c; + + /* Calculate the current pixel in a, and move the previous row pixel to c + * for the next time round the loop + */ + c = b; + a += *row; + *row++ = (png_byte)a; + } +} + +static void +png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row, + png_const_bytep prev_row) +{ + int bpp = (row_info->pixel_depth + 7) >> 3; + png_bytep rp_end = row + bpp; + + /* Process the first pixel in the row completely (this is the same as 'up' + * because there is only one candidate predictor for the first row). + */ + while (row < rp_end) + { + int a = *row + *prev_row++; + *row++ = (png_byte)a; + } + + /* Remainder */ + rp_end += row_info->rowbytes - bpp; + + while (row < rp_end) + { + int a, b, c, pa, pb, pc, p; + + c = *(prev_row - bpp); + a = *(row - bpp); + b = *prev_row++; + + p = b - c; + pc = a - c; + +# ifdef PNG_USE_ABS + pa = abs(p); + pb = abs(pc); + pc = abs(p + pc); +# else + pa = p < 0 ? -p : p; + pb = pc < 0 ? -pc : pc; + pc = (p + pc) < 0 ? -(p + pc) : p + pc; +# endif + + if (pb < pa) pa = pb, a = b; + if (pc < pa) a = c; + + c = b; + a += *row; + *row++ = (png_byte)a; + } +} + +#ifdef PNG_ARM_NEON + +#ifdef __linux__ +#include <stdio.h> +#include <elf.h> +#include <asm/hwcap.h> + +static int png_have_hwcap(unsigned cap) +{ + FILE *f = fopen("/proc/self/auxv", "r"); + Elf32_auxv_t aux; + int have_cap = 0; + + if (!f) + return 0; + + while (fread(&aux, sizeof(aux), 1, f) > 0) + { + if (aux.a_type == AT_HWCAP && + aux.a_un.a_val & cap) + { + have_cap = 1; + break; + } + } + + fclose(f); + + return have_cap; +} +#endif /* __linux__ */ + +static void +png_init_filter_functions_neon(png_structp pp, unsigned int bpp) +{ +#ifdef __linux__ + if (!png_have_hwcap(HWCAP_NEON)) + return; +#endif + + pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_neon; + + if (bpp == 3) + { + pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_neon; + pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_neon; + pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = + png_read_filter_row_paeth3_neon; + } + + else if (bpp == 4) + { + pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_neon; + pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_neon; + pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = + png_read_filter_row_paeth4_neon; + } +} +#endif /* PNG_ARM_NEON */ + +static void +png_init_filter_functions(png_structp pp) +{ + unsigned int bpp = (pp->pixel_depth + 7) >> 3; + + pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub; + pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up; + pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg; + if (bpp == 1) + pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = + png_read_filter_row_paeth_1byte_pixel; + else + pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = + png_read_filter_row_paeth_multibyte_pixel; + +#ifdef PNG_ARM_NEON + png_init_filter_functions_neon(pp, bpp); +#endif +} + +void /* PRIVATE */ +png_read_filter_row(png_structp pp, png_row_infop row_info, png_bytep row, + png_const_bytep prev_row, int filter) +{ + if (pp->read_filter[0] == NULL) + png_init_filter_functions(pp); + if (filter > PNG_FILTER_VALUE_NONE && filter < PNG_FILTER_VALUE_LAST) + pp->read_filter[filter-1](row_info, row, prev_row); +} + +#ifdef PNG_SEQUENTIAL_READ_SUPPORTED +void /* PRIVATE */ +png_read_finish_row(png_structp png_ptr) +{ +#ifdef PNG_READ_INTERLACING_SUPPORTED + /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ + + /* Start of interlace block */ + static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; + + /* Offset to next interlace block */ + static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; + + /* Start of interlace block in the y direction */ + static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1}; + + /* Offset to next interlace block in the y direction */ + static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2}; +#endif /* PNG_READ_INTERLACING_SUPPORTED */ + + png_debug(1, "in png_read_finish_row"); + png_ptr->row_number++; + if (png_ptr->row_number < png_ptr->num_rows) + return; + +#ifdef PNG_READ_INTERLACING_SUPPORTED + if (png_ptr->interlaced) + { + png_ptr->row_number = 0; + + /* TO DO: don't do this if prev_row isn't needed (requires + * read-ahead of the next row's filter byte. + */ + png_memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1); + + do + { + png_ptr->pass++; + + if (png_ptr->pass >= 7) + break; + + png_ptr->iwidth = (png_ptr->width + + png_pass_inc[png_ptr->pass] - 1 - + png_pass_start[png_ptr->pass]) / + png_pass_inc[png_ptr->pass]; + + if (!(png_ptr->transformations & PNG_INTERLACE)) + { + png_ptr->num_rows = (png_ptr->height + + png_pass_yinc[png_ptr->pass] - 1 - + png_pass_ystart[png_ptr->pass]) / + png_pass_yinc[png_ptr->pass]; + } + + else /* if (png_ptr->transformations & PNG_INTERLACE) */ + break; /* libpng deinterlacing sees every row */ + + } while (png_ptr->num_rows == 0 || png_ptr->iwidth == 0); + + if (png_ptr->pass < 7) + return; + } +#endif /* PNG_READ_INTERLACING_SUPPORTED */ + + if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED)) + { + char extra; + int ret; + + png_ptr->zstream.next_out = (Byte *)&extra; + png_ptr->zstream.avail_out = (uInt)1; + + for (;;) + { + if (!(png_ptr->zstream.avail_in)) + { + while (!png_ptr->idat_size) + { + png_crc_finish(png_ptr, 0); + png_ptr->idat_size = png_read_chunk_header(png_ptr); + if (png_ptr->chunk_name != png_IDAT) + png_error(png_ptr, "Not enough image data"); + } + + png_ptr->zstream.avail_in = (uInt)png_ptr->zbuf_size; + png_ptr->zstream.next_in = png_ptr->zbuf; + + if (png_ptr->zbuf_size > png_ptr->idat_size) + png_ptr->zstream.avail_in = (uInt)png_ptr->idat_size; + + png_crc_read(png_ptr, png_ptr->zbuf, png_ptr->zstream.avail_in); + png_ptr->idat_size -= png_ptr->zstream.avail_in; + } + + ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH); + + if (ret == Z_STREAM_END) + { + if (!(png_ptr->zstream.avail_out) || png_ptr->zstream.avail_in || + png_ptr->idat_size) + png_warning(png_ptr, "Extra compressed data"); + + png_ptr->mode |= PNG_AFTER_IDAT; + png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED; + break; + } + + if (ret != Z_OK) + png_error(png_ptr, png_ptr->zstream.msg ? png_ptr->zstream.msg : + "Decompression Error"); + + if (!(png_ptr->zstream.avail_out)) + { + png_warning(png_ptr, "Extra compressed data"); + png_ptr->mode |= PNG_AFTER_IDAT; + png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED; + break; + } + + } + png_ptr->zstream.avail_out = 0; + } + + if (png_ptr->idat_size || png_ptr->zstream.avail_in) + png_warning(png_ptr, "Extra compression data"); + + inflateReset(&png_ptr->zstream); + + png_ptr->mode |= PNG_AFTER_IDAT; +} +#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */ + +void /* PRIVATE */ +png_read_start_row(png_structp png_ptr) +{ +#ifdef PNG_READ_INTERLACING_SUPPORTED + /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ + + /* Start of interlace block */ + static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; + + /* Offset to next interlace block */ + static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; + + /* Start of interlace block in the y direction */ + static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1}; + + /* Offset to next interlace block in the y direction */ + static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2}; +#endif + + int max_pixel_depth; + png_size_t row_bytes; + + png_debug(1, "in png_read_start_row"); + png_ptr->zstream.avail_in = 0; +#ifdef PNG_READ_TRANSFORMS_SUPPORTED + png_init_read_transformations(png_ptr); +#endif +#ifdef PNG_READ_INTERLACING_SUPPORTED + if (png_ptr->interlaced) + { + if (!(png_ptr->transformations & PNG_INTERLACE)) + png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 - + png_pass_ystart[0]) / png_pass_yinc[0]; + + else + png_ptr->num_rows = png_ptr->height; + + png_ptr->iwidth = (png_ptr->width + + png_pass_inc[png_ptr->pass] - 1 - + png_pass_start[png_ptr->pass]) / + png_pass_inc[png_ptr->pass]; + } + + else +#endif /* PNG_READ_INTERLACING_SUPPORTED */ + { + png_ptr->num_rows = png_ptr->height; + png_ptr->iwidth = png_ptr->width; + } + + max_pixel_depth = png_ptr->pixel_depth; + + /* WARNING: * png_read_transform_info (pngrtran.c) performs a simpliar set of + * calculations to calculate the final pixel depth, then + * png_do_read_transforms actually does the transforms. This means that the + * code which effectively calculates this value is actually repeated in three + * separate places. They must all match. Innocent changes to the order of + * transformations can and will break libpng in a way that causes memory + * overwrites. + * + * TODO: fix this. + */ +#ifdef PNG_READ_PACK_SUPPORTED + if ((png_ptr->transformations & PNG_PACK) && png_ptr->bit_depth < 8) + max_pixel_depth = 8; +#endif + +#ifdef PNG_READ_EXPAND_SUPPORTED + if (png_ptr->transformations & PNG_EXPAND) + { + if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) + { + if (png_ptr->num_trans) + max_pixel_depth = 32; + + else + max_pixel_depth = 24; + } + + else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY) + { + if (max_pixel_depth < 8) + max_pixel_depth = 8; + + if (png_ptr->num_trans) + max_pixel_depth *= 2; + } + + else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB) + { + if (png_ptr->num_trans) + { + max_pixel_depth *= 4; + max_pixel_depth /= 3; + } + } + } +#endif + +#ifdef PNG_READ_EXPAND_16_SUPPORTED + if (png_ptr->transformations & PNG_EXPAND_16) + { +# ifdef PNG_READ_EXPAND_SUPPORTED + /* In fact it is an error if it isn't supported, but checking is + * the safe way. + */ + if (png_ptr->transformations & PNG_EXPAND) + { + if (png_ptr->bit_depth < 16) + max_pixel_depth *= 2; + } + else +# endif + png_ptr->transformations &= ~PNG_EXPAND_16; + } +#endif + +#ifdef PNG_READ_FILLER_SUPPORTED + if (png_ptr->transformations & (PNG_FILLER)) + { + if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY) + { + if (max_pixel_depth <= 8) + max_pixel_depth = 16; + + else + max_pixel_depth = 32; + } + + else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB || + png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) + { + if (max_pixel_depth <= 32) + max_pixel_depth = 32; + + else + max_pixel_depth = 64; + } + } +#endif + +#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED + if (png_ptr->transformations & PNG_GRAY_TO_RGB) + { + if ( +#ifdef PNG_READ_EXPAND_SUPPORTED + (png_ptr->num_trans && (png_ptr->transformations & PNG_EXPAND)) || +#endif +#ifdef PNG_READ_FILLER_SUPPORTED + (png_ptr->transformations & (PNG_FILLER)) || +#endif + png_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) + { + if (max_pixel_depth <= 16) + max_pixel_depth = 32; + + else + max_pixel_depth = 64; + } + + else + { + if (max_pixel_depth <= 8) + { + if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA) + max_pixel_depth = 32; + + else + max_pixel_depth = 24; + } + + else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA) + max_pixel_depth = 64; + + else + max_pixel_depth = 48; + } + } +#endif + +#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) && \ +defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) + if (png_ptr->transformations & PNG_USER_TRANSFORM) + { + int user_pixel_depth = png_ptr->user_transform_depth * + png_ptr->user_transform_channels; + + if (user_pixel_depth > max_pixel_depth) + max_pixel_depth = user_pixel_depth; + } +#endif + + /* This value is stored in png_struct and double checked in the row read + * code. + */ + png_ptr->maximum_pixel_depth = (png_byte)max_pixel_depth; + png_ptr->transformed_pixel_depth = 0; /* calculated on demand */ + + /* Align the width on the next larger 8 pixels. Mainly used + * for interlacing + */ + row_bytes = ((png_ptr->width + 7) & ~((png_uint_32)7)); + /* Calculate the maximum bytes needed, adding a byte and a pixel + * for safety's sake + */ + row_bytes = PNG_ROWBYTES(max_pixel_depth, row_bytes) + + 1 + ((max_pixel_depth + 7) >> 3); + +#ifdef PNG_MAX_MALLOC_64K + if (row_bytes > (png_uint_32)65536L) + png_error(png_ptr, "This image requires a row greater than 64KB"); +#endif + + if (row_bytes + 48 > png_ptr->old_big_row_buf_size) + { + png_free(png_ptr, png_ptr->big_row_buf); + png_free(png_ptr, png_ptr->big_prev_row); + + if (png_ptr->interlaced) + png_ptr->big_row_buf = (png_bytep)png_calloc(png_ptr, + row_bytes + 48); + + else + png_ptr->big_row_buf = (png_bytep)png_malloc(png_ptr, row_bytes + 48); + + png_ptr->big_prev_row = (png_bytep)png_malloc(png_ptr, row_bytes + 48); + +#ifdef PNG_ALIGNED_MEMORY_SUPPORTED + /* Use 16-byte aligned memory for row_buf with at least 16 bytes + * of padding before and after row_buf; treat prev_row similarly. + * NOTE: the alignment is to the start of the pixels, one beyond the start + * of the buffer, because of the filter byte. Prior to libpng 1.5.6 this + * was incorrect; the filter byte was aligned, which had the exact + * opposite effect of that intended. + */ + { + png_bytep temp = png_ptr->big_row_buf + 32; + int extra = (int)((temp - (png_bytep)0) & 0x0f); + png_ptr->row_buf = temp - extra - 1/*filter byte*/; + + temp = png_ptr->big_prev_row + 32; + extra = (int)((temp - (png_bytep)0) & 0x0f); + png_ptr->prev_row = temp - extra - 1/*filter byte*/; + } + +#else + /* Use 31 bytes of padding before and 17 bytes after row_buf. */ + png_ptr->row_buf = png_ptr->big_row_buf + 31; + png_ptr->prev_row = png_ptr->big_prev_row + 31; +#endif + png_ptr->old_big_row_buf_size = row_bytes + 48; + } + +#ifdef PNG_MAX_MALLOC_64K + if (png_ptr->rowbytes > 65535) + png_error(png_ptr, "This image requires a row greater than 64KB"); + +#endif + if (png_ptr->rowbytes > (PNG_SIZE_MAX - 1)) + png_error(png_ptr, "Row has too many bytes to allocate in memory"); + + png_memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1); + + png_debug1(3, "width = %u,", png_ptr->width); + png_debug1(3, "height = %u,", png_ptr->height); + png_debug1(3, "iwidth = %u,", png_ptr->iwidth); + png_debug1(3, "num_rows = %u,", png_ptr->num_rows); + png_debug1(3, "rowbytes = %lu,", (unsigned long)png_ptr->rowbytes); + png_debug1(3, "irowbytes = %lu", + (unsigned long)PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->iwidth) + 1); + + png_ptr->flags |= PNG_FLAG_ROW_INIT; +} +#endif /* PNG_READ_SUPPORTED */ |